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busrz5 | How does long-exposure photography work? | Technology | explainlikeimfive | {
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"When the cameras shutter is open for a long time, two things happen. More light hits the sensor and motion is blurred since the sensor records all tho movement it seen in that time."
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butitn | What is the difference between a "secure line" and a normal telephone line? | Technology | explainlikeimfive | {
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"A \"secure\" line has its audio scrambled so that a normal listener can't decipher what is being said. This used to take the form of analog modulation but now-a-days it could be as simple as encoding it into a digital form and then doing some light encryption on that digital data. & #x200B; EDIT: I said it *could* be as simple as light encryption. I never said it had to be light encryption and I have no interest in getting into a debate over what constitutes \"light\" encryption.",
"A regular phone line that isn't digital is just 2 wires that sends analog voice signals down them. They are extremely easy to listen in on, as, aside from when they are multiplexed with other phone lines by the communications provider, they are raw voice the entire run and you only need to clip onto the wires to hear everything being said on that line and no one will know they are being listened in on. To counter this, places that regularly talk about sensitive information have their phones set up with encryption devices or secure terminals in line with each phone. These devices are regularly updated with essentially software that allows them to scramble or encrypt the voice being sent and can be decrypted by the receiving phone. If one of the devices isn't up to date, the line might not be able to be secured successfully. So the caller has a secure device and calls a number to another phone with a secure device and the link is made un-secure. When they need to go secure, they announce they are going secure to the other person and press a button that scrambles/encrypts their line and then the other end presses a button to de-scramble and now they can talk. If anyone tried to tap into their line they would hear garbage or nothing at all, just power on the line. These secure devices usually have a pin or password or some kind of credentials associated with them so not just anyone can operate them.",
"In this case, you are referring to COMSEC- Communication Security, more specifically Cryptographic Security & #x200B; Whether between analog (Copper lines) or VOIP lines, both system will require the use of Cryptographic modules to secure the communication with complementing asymmetrical crypto keys. While cryptographic security has evolved in the past years, the basis is still the same. When a phone A calls Phone B, by default the line is unsecured. When both receivers are picked up, the units negotiate with each other to find a matching crypto key and then the line is scrambled (unless you have that same key to decrypt the signal when intercepted). & #x200B; Think of the old 24 TV show and them referring to STE or STU-III units. However, what you didn't see was the 5-10 sec delay for the \"secure\" part to happen after dialing. & #x200B; Here are some additionaly links for you [ URL_5 ]( URL_2 ) [ URL_3 ]( URL_7 ) [ URL_0 ]( URL_1 ) [ URL_6 ]( URL_4 )",
"to make it super ELI5. look at it as a math problem. If line is unsecured you are just sending the correct answer over it, so who ever chimes in can hear that answer. But if you and who ever you are talking to make up a new equation . One only you and person you talk to know to to solvee Now then u send the answer, first it is put into the equation and send that. Now who ever tries to listen onto you, will only hear that equation, with out prior knowledge on how that eqution is made or solved, they have no way to know what you are really saying",
"ELI5 version: the physical lines are the same, it's just the data sent over the lines that are different. Encrypted/scrambled data is sent over the line/airwaves rather than plain signals"
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"https://en.wikipedia.org/wiki/Secure_communication",
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butttl | How did older films edit in the credits, specifically in actual footage? | Clarification: Actual footage meaning something that was filmed and not just black backgrounds. | Technology | explainlikeimfive | {
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"Many techniques have been used over the years, but one of the oldest is to paint the credits on a clear sheet of plastic, then just put that on top of the existing footage.",
"To add on to what /u/FullMetalDove said, there's also the process of [optical printing]( URL_0 ), which is setup that takes footage of film. You matte out where the credits will go, which leaves the credits area unexposed, rewind the film and shoot the credits again, with the negative space matted out this time.",
"Didn't they sometimes use glass panes with the credits painted on?"
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buvmsp | When a game gets remastered do they completely rebuild it in a new engine or do they use the old game files and simply update the graphics? | Technology | explainlikeimfive | {
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"Former game developer here, & #x200B; There is the dream that they will repurpose as much material as possible. But consider an older game on an older, different platform was likely written specifically for that platform. Portability would approach zero. The studio would likely start with an engine that already runs on their new target platform, that they're already familiar with in house as a base. Parts of the old engine will be ported, mostly physics, controls, and gameplay elements, IF it isn't riddled with platform specific code. & #x200B; Lots of visual assets are not usable. That's the whole point of remastering. An artist might LOOK at it, but they're going to recreate from scratch. It's just easier and aligns with their workflow. & #x200B; Even content like dialog will likely be converted into a new file format. & #x200B; Typically, a remaster is as costly as developing a new game from scratch, it's why studios almost never do it, it's not worth the money.",
"Well there’s a difference between “remake” and “remaster” Remakes like Shadow Of The Colossus, Crash Bandicoot, and Resident Evil 2, rebuild the game in a new engine from the ground up. Remasters like Last Of Us, God Of War 3, and Call Of Duty: 4 use existing games but enhance them to look and play smoother on new hardware. There’s a good bit more that goes into it all of course, but that’s the ELI5 difference.",
"Usually the latter. The existing code gets ported to a new platform and updated to support whatever new features they want to add. Although there are a few cases where a game has been rebuilt from scratch but as an almost like for like match with the original. Shadow of the Collosus on PS4 comes to mind. But you might consider that a remake rather than a remaster."
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buvxjo | Why are 144hz monitors more popular than 120hz? | Technology | explainlikeimfive | {
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"It's a mix of display connection limitations and marketing. Before displayport and higher versions of HDMI, the display cable that could transfer the most data was Dual Link DVI. The initial 120 Hz refresh monitors were at 1080p resolution. 120 Hz made sense because it was double 60 Hz, the standard monitor refresh rate and divisible by 24, the movie frame rate. Monitor manufacturers wanted to distinguish their monitors so they pushed the limits of Dual Link DVI. It turns out 144 Hz at 1080p was close to the maximum supported data rate for the cable. So monitors came out with 144 Hz refresh rate and 144 > 120. The number kinda got stuck as the new threshold so most high refresh monitors set that as the standard.",
"Good marketing. 144hz monitors introduce a hiccup when playing 30 and 60 FPS locked video or games if you don't modify the monitor settings every time. 120 is divisible by both, making it a smoother and more versatile experience with fewer adjustments. If all you do is play CSGO at minimum graphics settings in hopes you'll one day be pro, maybe 144hz is worth it, but for 99.999% of people, 120hz will provide a better experience",
"Films are shot at 24 frames per second. You want to upscale in multiples of that. 120hz = 5x 144hz=6x. As to why is 144 more popular, higher frame rate = more good and the cost is usually comparable."
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buwnwc | How are some animation movies so realistic? | Im talking about movies like "The adventures of Tintin" and "A christmas carol" by Disney. How are those movies so realistic? how are they made? | Technology | explainlikeimfive | {
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"I think it mostly comes down to the style of animation. Even as technology has improved over the years (look at the difference in animation quality between toy story 1 and 2 for example), certain styles \"look\" more realistic than others. This is on purpose. If you look at a recent film like Incredibles 2, the quality of animation is great but do the characters look \"realistic\"? Nope, they're meant to look like cartoons. It's an animated film and it knows it. Going off your example of the adventures of Tintin or A christmas carol, the characters and style were designed to look more photorealistic. It's just the way the animators decided to make it. You can do it with any film; but you might noticed that photorealism isn't always super prominent in the film industry. Most high budget animated films aren't meant to necessarily look \"realistic\", because the beauty of animation is that you can make it look like whatever you want. Certain styles are more desirable than others. If you remember the film The Polar Express, it was heavily criticized for using a photorealistic style with characters that simply weren't lifelike enough. When your goal is to look as realistic and as close to real life as possible, anything lacking in your quality of animation is going to be much more noticeable."
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buxdg5 | - how do hearing aids work? | Technology | explainlikeimfive | {
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"I am not an expert so would be happy to see an expert chime in, but I can speak as a user of hearing aids. I think cheaper hearing aid models do increase the volume of everything. This isn’t helpful as sounds can “blend” together for hearing-impaired individuals. More expensive models take the results of your specific hearing test and identify only the pitch ranges that need to be boosted, and increase the volume there. So if you can normally hear bass tones but can’t hear higher-pitches, they would only boost the high-pitches. No solution yet is perfect though and the extent of hearing loss is highly individual, so they very well might be experiencing an overwhelming garbling of sounds even with decent hearing aids. I definitely shy away from any place with background noise if I want to be able to hold a conversation.",
"Hearing and hearing loss is quite complex. Hearings aids are not capable of restoring all the properties of the healthy cochlea, but the basic volume compensation goes approximately like this: Our hearing is seperated into frequency bands. You can imagine this with a xylophone, for true eli5. When you lose hearing, your thresholds generally decline in the higher frequency ranges. So you cannot hear the short xylophone parts that well. In the frequency bands where you have hearing loss you need higher volumes to be able to hear it. For example you have to smack harder on the short parts of the xylophone to produce the same volume as a light smack on the long one. Hearing aids follow this frequency band approach and amplify incoming sounds per frequency band, based on your individual auditory thresholds. So, again assuming high frequency hearing loss, it leaves the long xylophone sticks unaltered, but strongly amplifies the short xylophone stick. In short: Without hearing aid and gently tapping a xylophone Ding ding ding ding....... With hearing aid and gently tapping a xylophone Ding ding ding ding ding ding However. As I mentioned hearing loss is complex and covers far more than just increased thresholds. For example the frequency specificity goes way down in the hearing impaired system. Going back to the xylophone, in the normal hearing system each part activates a single frequency band, but in the impaired system multiple parts of the xylophone might activate the same frequency band in the cochlea. Because of the way loudness perception works, this means that when you have multiple xylophone sticks activating the same band, it appears louder."
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bv0ali | How do touch lamps work? | Technology | explainlikeimfive | {
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"They use something called capacitance. It has a wire attach to the outside of the lamp that has a small voltage applied to it which is basically trying to shove electrons into the metal. The metal can only hold so many electrons, but if you touch it, some of them leak into your body, and the wire can now push more electrons into the lamp body. When this happens, a small circuit detects this small flow of electricity and turns on the lamp."
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bv1ghd | How do police scanners work? | The police scanners that the public can use in their car to detect police nearby | Technology | explainlikeimfive | {
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"The term has a number of meanings. One meaning of 'police scanner' is just a radio that is tuned to the radio channels that the police use. You can hear their conversations. Another is a 'radar scanner', that listens for the signals given out by radar speed measurement devices. A similar device could be made that detects laser pulses from lidar speed detectors. (Less useful, because you'd only detect them as they detect your speed.)"
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bv1yhn | How are scientists able to discover so much about space/blcak holes when we have such limited access to it? | Technology | explainlikeimfive | {
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"text": [
"Observation and experimentation. We can't do anything with black holes, but we can do lots of stuff with light and solid matter of all sorts of different types. We do tons of experiments with what we have to learn all of its properties, and then we observe how it acts differently around a black hole. Similarly, while we can't bring a star into a laboratory to experiment with it, we've observed *lots* of them, very closely, at every stage of development, and come to a pretty solid understanding of how they work, so, similarly when we observe what happens to them near black holes we learn all sorts of stuff. Then we take all that data and use, as u/suwampert said, math. The data gives us points to base the math off of, and then we use the math to predict and hypothesize(in fact, when we were learning about stars and gravity the math actually told us black holes were there before we ever actually observed them, and then they proved to be real, and over and over again since they do what we expect them to\\[usually\\]), and then parts of our predictions and hypotheses either prove true or don't as we make further observations and do further experiments with things like vacuum chambers and particle accelerators."
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bv2q7w | Why do arcade video games and flight simulators use mirrors to reflect the monitors instead of just letting you look at the monitor? | Technology | explainlikeimfive | {
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"text": [
"Talking about the old school arcade cabinets? CRT monitors are big, and deep. If they put the CRT upright at eye level the cabinet would be twice as deep. Laying it down facing up at a mirror is much more compact."
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bv3evd | How are electronics made water resistant or waterproof, even when they have perforated or moveable parts (i.e. like a phone )? | Technology | explainlikeimfive | {
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"For total submersion you use parts that are sealed. The conductors of the connectors (charger, headphone jack) don't let water through. They use non corrosive metals like gold, which don't rust away when exposed to standing water. The phone itself is sealed using rubber o-rings that prevent water from entering through the gaps where the enclosure needs to be sealed. The speakers are connected to thin films that iirc are glued or otherwise sealed against the top of the enclosure so water doesn't enter the electrical area. There is some controversy over design decisions like the purported reason for Apple removing the headphone jack to make the iPhone water tight, which is kinda true because it removes a point of failure and kinda false because there were other reasons, like allowing more space on the PCB for them to increase the battery size, or making money from air pods. At the end of the day any feature as big as waterproofing requires so many changes to the enclosure and assembly that it drastically impacts every other aspect of the design."
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bv3t62 | Nowadays we even have cellphones that record in 4k. Why do the TV stations still use that big cameras? (Professional video camera, aka television camera) | Technology | explainlikeimfive | {
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"text": [
"Depth of field, focusing ability, and visual detail. There is versatility in the larger versions. Have you noticed your cell phone camera takes _awful_ pictures of the moon, compared to what you see through your eyeball? Same type of thing. (Also — what phone records in 4k?)",
"Its arguable that phone optics will never be as good as the real thing. Yes you can record in 4k with a phone, but I doubt we will have a practical 35mm+ sensor in a cell phone along with very good optics(lenses) any time soon because then your phone would easily weigh 2 pounds at least. Resolution is not the end-all-be-all of quality/clarity. The size of the imaging sensor and quality of the lens matter just as much, if not more."
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bv6cyz | How do relational databases work? | Technology | explainlikeimfive | {
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"Let's say we're trying to maintain a family tree. We know about people. Every person has a name, a father, a mother, a date of birth, maybe a date of death, and maybe a list of addresses (birth place, places where they lived, burial site, etc.). Imagine writing all this down on a sheet of paper in a table format. Each person has a row, and each thing we know about that person has a column. How do we deal with those addresses? Each address has a number, a street, a city, a state or province, a country, and maybe a postal code. So maybe five or six columns for each address. If you just record birth place and burial site, that's ten or twelve columns right there. The table starts getting a little cramped. If we want to track every place the person lived, it gets even worse, and what happens if you lay out the table to keep track of four total addresses, but someone has lived in ten different places? We might solve the problem by writing things down in two different tables. We have one that lists the people, and we have another where we list all the addresses we know. Then in the table listing the people, we have one column for each address where we use some sort of number or tag to indicate which address we are referring to. That makes the table easier to read. If you don't need the addresses when you're reading the list of people, you can just ignore those columns, and they don't really get in the way. If you need the address, you can look it up in the address table. It doesn't solve the problem of how you deal with some people having a lot of addresses, though. So, there's another approach. You can make a third table. In this one you have three columns. For each person, you have a row for each address we know about them. One column indicates who the person is. One indicates which address we want. And a third column says what the address means \"birth place,\" \"burial site,\" \"residence\", etc. This approach is more complicated. To find a person's birth place, you look for the row with their tag on it and the meaning \"birth place\". That gives you the indicator for the address. Then you can look up that address in the addresses table. This is more complicated, but it's more flexible. It lets you track as many addresses per person as you like. This new table, by the way, is called an \"association table\" because it associates or connects two other table: people, and addresses. Also, it means that you don't have to have columns for addresses in the table of people, making it a little easier to read. For all of this to work, these different tables need to have some way of pointing to a specific row in another table. For the association table, it's no good to write \"John Smith\" for the person, because there are so many \"John Smiths\". There are several ways to deal with this, but the easiest is to add another column to the people table where we write a unique number for each person. Then we can refer to that person by their number. That column is what we call an ID or a \"key\". This is the core of relational databases but on paper. You have more than one table written down, and you have IDs or keys for each row in the tables that you can use to relate two or more tables together. There's a lot more going on in relational database than this, but this is kind of the heart of it.",
"Lets give it a try: A relational DB is a way for storing and accessing data. It is based on \"relational algebra\". Most commonly, a data model is designed first, then data is deconstructed by the process of \"normalization\". This aims to turn your data in a basic form like into separate tables. E.g. one table for customers and one for orders. The so called \"keys\" are important so you can \"join\" the data again and make a report that answers questions like \"what did each customer order?\". One benefit comes from you not needing to store all those \"answers\" and reports permanently, but rather modify your \"query\". So why not put it in a single table then you ask? Because the normalized data is more flexible and eliminates waste like storing same data multiple times. It's one of the key features of RDBMS, which was invented around the 70's where hardware was very limited. The language to query the data is called SQL; there are variations to this like T-SQL or PL/SQL. An RDBMS is the system/software you choose e.g. SQL Server or Oracle. So taking the example, when an RDBMS contains the pure facts about customers and orders, it can say \"ask me anything about the customers and orders and i can answer them for you\". This can include something basic like \"how many customers do we have?\" to more complex ones like \"what is the most ordered item and by which customer?\" Source: I'm a DBA and developer."
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bv8fej | Why do some airplanes leave a white trail after them while others do not? | Technology | explainlikeimfive | {
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"The same reason some mornings you can see your breath and other mornings you cannot. Just like you, airplanes exhaust hot, humid air as a result of burning fuel. When conditions are right in the surrounding air, that water condenses into tiny droplets which are seen as white trails, and other times it remains the same invisible exhaust.",
"All jet planes have potential to have trails behind them. The trails are condensed water vapor. When the jet engines fire they produce co2 and water vapor, if the plane is in cold enough environment it causes the water vapor to condense leaving a visible trail.",
"When humidity in the air reaches 100%, water can start to condense. \"Can\" is important: Water vapor needs a point where it can start to form a drop, else it's going to have a tough time becoming a liquid. High up in the sky, it's quite normal that the air reaches a humidity where it's \"supersaturated\", meaning humidity is higher than 100%. In comes the airplane: The airplane exhaust contains a lot of water, and it also emits pollutants that allow the water vapor to form droplets. These droplets then allow the humidity from the surrounding, supersaturated air to condense and form droplets on their own. The result is a chain reaction that goes on for a long time, forming the visible contrail, and only stopping once there's no longer any water vapor left to condense. So what you see is not actually condensed aircraft exhaust - it's a cloud that was seeded by the aircraft exhaust. You might have heard about the Chinese using cloud seeding to prevent rain during the olympics in Beijing - that was the same effect: They wanted to create clouds so it would start raining somewhere else. So if a plane does not leave a contrail, it's because there isn't any supersaturated air."
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bv9d67 | How do game designers program the characters to behave in different levels of difficulty? | e.g. A soldier shooting you faster on Veteran level but taking a bit to shoot you in Amateur. | Technology | explainlikeimfive | {
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"As an example, in Bioshock the splicers, when they spot you for the first time, always miss their first shot by design. That way the player gets a moment to recognize and react to the threat before they actually take damage. Scaling up the difficulty for the game might involve removing that feature or other intentional AI behavioral handicaps. If the developer is lazy (Bioware and Anthem or Bethesda and Skyrim) they'll just tack a modifier onto the health and damage calculations for an enemy. A Giant in Skyrim on Normal mode might have 150 x [1 x player level] x 1 health and do 30 x [.5 x player level] x 1 damage, but in hard mode he has 150 x [1 x player level] x 1.75 health and does 30 x [.5 x player level] x 3 damage. EDIT:: Markup, please ;_;",
"In simple terms, they manipulate variables within the code to produce desired outcomes. It's all just numbers, so everything from physics, to reaction times, to anything else you can think of can be changed. The difficulty levels are essentially just presets with those variables preconfigured to specific numbers."
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bvaczk | When you delete stuff from your phone (pictures, videos etc.) where does all that data go? | Technology | explainlikeimfive | {
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"text": [
"Actually nowhere. Imagine storage as a bunch of words in a notebook. When you \"delete\" something you actually are just telling your computer (phone) that you don't care about the contents of the notebook anymore. You throw that notebook in a pile that you designate as \"good to write in\". The notebook isn't actually cleared, you just no longer care that it has anything written in it. Now when you have something else to write, you take out that notebook and simply write directly over the last thing that was there. The last thing isn't \"deleted\" per se but is overwritten. Actually with many programs you can look at your own storage and see if there is enough of your previous files to restore them from storage. If you never want this to happen (or you're doing some shady stuff) there are programs that essentially are data \"shredders\". They continuously overwrite a certain memory location until the data is completely unrestorable. From the analogy earlier it's like if you took a permanent marker and just kept drawing over all the pages until you couldn't make out what was underneath anymore.",
"It doesn't go anywhere. Just like deleting stuff on your computer, the operating system simply changes the memory addresses the data is in as available to be overwritten. The data is still there at first, just not accessible without some unique tools. And future data writing is now allowed to write over it.",
"Imagine computer memory as a bunch of switches, either up or down, on or off. The switches themselves go nowhere, they just get flipped on and off in different combinations to mean different things. For example, if you have just two switches, two positions of binary, if they're both off (00), this can represent the number 0. If the left is off but the right is on (01) then this can represent the number 1. If the left one is on but the right one is off (10), this can represent the number 2. And finally if they're both on (11) then this can represent the number 3. Of course, we need to represent numbers a lot higher than 3, so you basically have -a lot- of these nano switches to be able to represent very large numbers, and then those numbers can be used to represent other things, like letters, colors, etc."
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bvay7a | why is Australian internet so bad compared to the rest of the 1st world? | Technology | explainlikeimfive | {
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"Depends on which internet you're talking about. Connecting from your Australian PC to an Austrailian Server should be first-world speeds. If you're connecting to a server outside the country, odds it's thousands of miles away, so it takes awhile for every message to literally travel those miles. Unfortunately, that's a problem that can't be solved until we develop faster than light technology. As for why that's a hard limit I'll let [Admiral Grace Hopper]( URL_0 ) explain that to you.",
"Is it? It's a bit higher than the world average, and not so low as to really notice on the overall rankings. Of course it underperforms compared to the top 10. & #x200B; Ultimately the poor performance of Australian internet is down to two things; your politicians don't want to fund it (an attempt was made, but was later repealed), and the vast empty space between the major city centers means building and maintaining infrastructure is less cost-effective and reliable compared to satellite."
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bvd2nq | What does "bottlenecking" means in computer stuff? | Technology | explainlikeimfive | {
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"Think about running a relay race. One runner hands the baton off to another, and so on. Your slowest runner is the \"bottleneck\". No matter how fast the other runners run, the slowest runner will be the one that determines when you're finished. Even if the others run super super fast, maybe the slow guy takes a stroll because he's old and doesn't want to run. A \"bottleneck\" is a process term for saying what process (i.e. the slow runner above) is causing the system to slowdown. In computing terms, it means the same, just because you have a fast component X and component Y, if component (or program) Z is slow, and they all need to work, then the speed will be determined by component Z.",
"Your computer can only operate as fast as its slowest part. The various parts of your computer must interact in order to accomplish tasks, but if one part is slower than the rest than all the other parts have to slow down whenever they are working with that one part. If you can identify what that part is an upgrade it, your computer as a whole will run faster. To give you a real world example: If your CPU and RAM were having a conversation in real time, if a hard drive were to walk into the room it would be speaking at a rate of 1 word per **year**. That's how slow hard drives are compared to everything else in your computer, and why upgrading to SSDs make such a difference over spinning disk.",
"Say you have a computer that you've had for 10 years. You've upgraded everything. The video card (what you see) the RAM (short term memory) but not the CPU or hard drive (brain / long term memory respectively) & #x200B; and you go to load up the latest and greatest game. Put it onto it's highest settings. & #x200B; You're likely to encounter a slow choppy game at this point. As the graphics card can render it, but some of the game is handled by your CPU which will be at 100% usage. It will be maxed out so now you can only run the game as fast as your slowest piece... thus bottlenecking performance."
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bvd844 | How does cloud computing work? | Technology | explainlikeimfive | {
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"\"There is no such thing as the Cloud, it's just someone elses server.\" Basically instead of having servers and equipment onsite for your business you can rent servers from a 3rd party. The term cloud refers to a concept in networking akin to 'black box', in that you know it works but you have no idea what's going go inside. The big upside to Cloud computing is that someone else takes care of the hardware and infrastructure for you (power, cooling, etc) so you don't need onsite facilities and staff to maintain it. The downside is you often have very little control of the hardware, what's used, who you share it with, where it's located, and how often it's maintained. Many businesses that operate on the Cloud model operate with an 'out of site, out of mind' mentality and assume it's the cheaper route, which is not necessarily the case."
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bveaaj | When media outlets say x amount of people watched a certain game, how do they calculate that number? | Technology | explainlikeimfive | {
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"They don't calculate it. Generally these estimates are from Nielsen, a company that specializes, among other things, in gathering TV viewership data. Nielsen has select households, called \"Nielsen Households\" which they gather viewership data from (and they get data in lots of other methods), from this small sample of people, they extrapolate to get an estimate of the total amount of people that watched."
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bvfux3 | How does a capacitor work? | Technology | explainlikeimfive | {
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"A capacitor is two conductors seperated by a thin insulator. The conductors are close enough to interact but not enough to transfer electricity. This allows charge to build up on one of the conductors. The charge can then be dissipated all at once by completing the circuit. The capacity depends on the size/ammount of electrolyte used as an insulator and the size of the conductors."
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bvi55r | How do people do extensive research? | Technology | explainlikeimfive | {
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"It really depends what you’re trying to research. Finding out dinosaur facts vs inventing a new machine learning algorithm both require research, but they’d be approached in a massively different way. Wikipedia is great for the former, while I’d be reading papers on arxiv or skimming the websites of academics to influence the latter. Research is a very broad term",
"Google scholar is a fantastic resource. It's useful to grasp the concept of key words vs key phrases. Rather than \"Correlation of pollution and country development\" first try \"pollution developed countries\". Another good idea is to widen/narrow your question depending on the specific info you need for each section.",
"Research for personal interest? Set aside time every day to read anything you can find on the topic. As often as possible, make the things you read be primary sources (direct accounts, research papers, etc), rather than people summarizing other things they have read (which you should have been reading for yourself). For a project with a timeline? Start with the google search, find some sites which have what you consider to be good information which also list their sources. Then go read those sources. Then read the sources of the sources. Then google search all over again, because now you know more terminology about the subject and will get better results."
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bvig0h | Why can my laptop pick up my WiFi very well, but my phone, on the same desk, hardly connect at all? | Technology | explainlikeimfive | {
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"I would only assume better hardware in the laptop given its increased form factor. Same reason you won't get a core i9 and 32gb ram in a smartphone. Edit - forgot to add phones are more power conscious so reduce performance of areas to prolong life.",
"Laptops are larger so they can fit a bigger and better wifi antenna, usually the wifi antenna is built into the edge of the laptop's monitor."
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bviuti | Why do some countries have differently shaped electrical outlets/adapters? | Technology | explainlikeimfive | {
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"text": [
"Most countries developed their own standards when electricity started being used. Some were better than others, and some decided to take the better ideas and combine them. There would be a bit of protectionism involved as well. You don't want someone buying an American product when they could buy manufactured right here in France, or vice versa. Travel was also a lot more difficult back then as well. Finally those that were travelling were not carrying a lot of electrical devices with them. After these systems were developed, it's much harder to go back and change them."
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bvk75u | LNG gas process? | Watched this video a couple times just need the process dumbed down please? URL_0 | Technology | explainlikeimfive | {
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"Natural gas is formed under the earth from the remnants of plants. These gases are pumped from the earth but contain a lot of impurities. It goes to a complex process that removes the impurities and is then cooled to liquid form where it is transported for use."
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bvkmz6 | Lane Detection System: What kind of sorcery is this?! | Reposted because I forgot to tag the title. Ok, I'm going to jump right into this. My husband and I rented a car to make our family vacation trip from Texas to Florida. We were given a newer Toyota Camry, as we requested a car of similar size to our car, which happens to be a 2001 Toyota Camry. My mind was just blown by this car. My husband veered off the road just slightly, and an alarm started going off in the car. I am in my 30s with 2 teenagers, so I thought nothing could surprise me. I was wrong. As soon as the alarm went off, I jumped in my seat in excitement and asked if it was what I thought it was. We have now been playing with this system to see how it works. I had to pick my jaw up off of my lap because HOW DOES IT KNOW??!!?? When there is a slight bend in he road, we don't use a blinker, but we turn the wheel ever so slightly, and it doesn't go off. However, if we're in a straight lane and we turn the wheel so the car moves into the next lane a little or into the shoulder, we get the alarm. It doesn't come on when we use the blinker, and I understand how that would work, but I can't figure this out, and I don't understand any materials I've found on it, so someone please, ELI5! | Technology | explainlikeimfive | {
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"The car has a camera and a computer. The camera takes a picture and the computer combs through it and rates each part the image looking for lines. If it's pretty sure that something is a line, it gives it a high score. If it isn't sure, it gives it a lower score. When the computer is done, it has a pretty good idea where the lane markings are, because compared to the rest of the road, other cars on the road, trees and sky, the lane markings will truly stand out as the only pure lines in the image. And once you know where those lines are, it's easy to tell whether the car is crossing them.",
"There's a camera in the top center behind the windshield. A software analyzes the videostream to detect lane markings and depending on the car also other things, such as pedestrians or traffic signs. Some systems are better and some are worse. I've seen cars that can detect lane markings even in the worst conditions, while others already fail when the markings are worn out. In the end though, the system is usually as good as the software is. Some cars use the lane system to also automatically steer and keep the car in the center of the lane. Also, a lot of cars combine the system with an adaptive cruise control that can follow the car in front of you and adjusts the speed automatically to follow the traffic. That system can either also use a camera, or radars that are mounted somewhere in the front of the car. In very advanced systems, cars can also do automatic lane changes and fancy stuff like that.",
"I think this site explains it really well, especially since there are a few different types of warnings/indications and systems: URL_0 But basically, there is a camera that is facing the road in front of the car. It is usually installed high up in the windshield. The camera detects any lane markings ahead and then can tell if the car is staying within those markings or if it is veering off course. The technology relies on clearly marked roads so if you're on a dirt road or on a highway where the lane markings have been faded or stripped down it might not work that well. And there are different versions of the system - some of them resist you changing lanes without putting the turn signal on first, for instance, and others just give you a warning that you're going out of the lane."
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bvl0cj | How does an internet search work? Do they get slower for each new internet page created or are there mecanisms to avoid that? | Technology | explainlikeimfive | {
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"The search engine couldn't search all websites each time someone puts in a search word. Instead, it creates a list of all words or phrases it finds on every webpage, and next to each word it writes down the links to every webpage containing that word. Now if someone puts in a search term, the search engine can simply check its list and immediately give you your search results. Such a list is called an index. The search engine will visit all websites on a regular basis in order to see if something's changed. This is called crawling. Does internet search get slower for each new internet page? Well, updating the index will take longer each time a new website is created. Looking up something in the index will also take longer if the index gets bigger. However, servers get faster and faster, and database systems probably keep getting more efficient. So I doubt this would be noticeable.",
"To put very simply, Google has a robot that is constantly reading the entire internet and organizing it so that only pages relevant to what you type appear.",
"Others have mentioned how, in general, a search engine crawls the internet and indexes the pages in advance, but there's probably value in talking specifically about PageRank, which is how Google became the winner of the early search engine competition. Put simply, since you're five, the indexer may tell you what subjects a web site covers, but it doesn't really tell you which websites are *the best* or *the most important* for your search terms. PageRank uses links from other websites as a way to determine how important a site is. Lots of other people link to the Wikipedia entry for a subject, so therefore, that Wikipedia entry must be one of the most important websites about that subject and it should come up really early in the search results. Now, of course, Google does more than that to rank search results these days, but PageRank was pretty innovative, and was one of the big things that put Google out in front."
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bvl1xj | How does an atomic clock work? | Technology | explainlikeimfive | {
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"TL:DR Atoms vibrate regularly and this vibration is measured and converted into vibrations per second and thus seconds. First, think of what a clock actually is. A measure of a time period. On original pendulum clocks this time period was kept relatively constant by something called \"Simple Harmonic Motion\" (something swinging backwards and forwards) which basically states that for a string (or pendulum) in this case with a fixed mass at the end of it the time period of its oscillation (how long it takes to go swing then return to its original position) will be constant. The actual equation is T = 2 **π \\* root**(l/g) Where l = length of pendulum and g = gravitational field strength (earth = 9.81) But as you can see if we know the time period we want which is 2 seconds (remember that each \"half swing\" is one full second on a clock) we can work out exactly the length of the pendulum we need to produce it hence why lots of grandfather clocks are all similar in size. This is obviously helped along by electricity but that's the premise of a clock modern clocks just use stuff like the frequency of electrical signals etc to keep that steady period. & #x200B; So now we should have a fair outlook on what an atomic clock has to do. Find something that is regular in frequency. Frequency is actually just 1/T so if a grandfather clock had a time period (there and back) of 2 seconds its frequency is just 0.5Hz or 1/2Hz. & #x200B; Now comes the \"atomic\" stuff: Atoms are constantly absorbing energy from lots of sources but mainly from EM waves. When an atom absorbs these waves lots of things can happen including excitation of electrons which can then release that energy at lower states. But for an ELI5 it really doesn't matter what does matter is that atoms of everything are in a constant state of movement, vibration and \"resonance\" which in itself has a set Time period and frequency of oscillation. What makes this amazing for timekeeping is that any single atom of one isotope of an element or ion will resonate at the exact same frequency as the next making it super convenient for timekeeping as these oscillations could happen here or on venus and it would never change. Therefore by using a method to find how quickly they resonate you can then find how many oscillations are in 1 second and match your clocks accordingly. & #x200B; In the real world, the isotope used is Caesium-133 which has 9,192,631,770 oscillations in a second. You see the level of precision now? This means that atomic clocks are accurate down to 1x10^(-9) seconds. & #x200B; Real definition of a second: “The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 Kelvin.” ##"
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bvmfbr | How/Why is the animation in the Spongebob movies different from the TV show? | Technology | explainlikeimfive | {
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"text": [
"This happens with all cartoons that are made into movies if you watch The Simpsons Movie you'll also notice this it's mostly because they have a better budget, a bigger one.. to work with for a movie, because unlike television, the movie makes more money."
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bvmg12 | How did commanders effectively coordinate and move large armies before electricity? | Technology | explainlikeimfive | {
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"They used drums or horns or just yelled shit and the rest of the army would pass orders by also yelling shit. Or for armies that are spread out they would send messengers.",
"Well for starters, there's the chain of command. Much like armed forces still use today. The commander doesn't speak to each part of his army. The commander relays his orders to generals. The generals relay their orders to the officers. The officers to leadership down the chain of command and so on. Secondly, before mechanisation, armies were relatively slow to move around. They had to march everywhere they went and were followed by a long train of supplies, craftsmen and other followers. Armies are pretty vulnerable while on the march, to avoid being ambushed they usually send out scouts in every direction. Those scouts would gather information on the lay of the land and potential enemy movement for miles or even tens of miles around a marching army and report back to an army's general. Based on the information he receives, the general can inform his officers and those officers will inform their troops. At the same time, runners or messengers on horseback are sent back and forth between allied commanders, forts, command posts, basically, any place that needs to be informed, they also run orders back and forth. This is how an overall commander stays up to date on his campaign. Obviously, travel time and changing conditions mean that not everyone is informed at all times. That's why the overall commander designs strategies that allow army generals leeway in how they do things. The commander defines the goals but the generals have freedom in how to achieve those goals. When battles start, it works very similarly at a smaller scale. The general or overall commander resides at a command post or a field post overlooking the battlefield. If things go according to plan, the regiment or unit commanders have been briefed on the overall strategy and their role in the battle. Smoke signals, flag signals, runners etc. are used to send out commanders or relay information between the commander and his army components. Individual units often had musicians that could sound out orders for the troops. Different musical signals for things like march the formation, wheel left, wheel right, charge, retreat etc. Obviously, it's not as fast modern communication methods but your opponent was dealing with the same limitations."
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bvmz69 | How did people start measuring distance at sea where it's water all around? | Today I know we have the technology to position anything accurately within a few feet. But how would sailors in old times measure distance and have maps of the sea? Why is there a nautical mile and different from the land mile? | Technology | explainlikeimfive | {
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"Speed of ship and stars. Drop a buoy in the water from the front and count the time it takes to get to aft. That gives you the knots or speed. Do that every so often and navigate by stars. Wasn't accurate like gps but it worked well enough at the time. Also ocean currents weren't really known of back then.",
"Dead Reckoning: speed, heading, and distance from a known starting point. We know what direction we're going because we have a compass. We know how long we were pointed in that direction because we keep accurate time. We know how fast we're going because we can drop a float and count the knots over a minute. A nautical mile is a mathematical construction from a spherical Earth. A circle is divided into 360 \"degrees\", and each degree is divided into 60 \"minutes\". A nautical mile is equal to 1 minute of latitude, so there are exactly 5400 nautical miles between any point on the equator and the north pole. This allows a navigator to chart a course without doing any dumb conversions.",
"That's a truly hard problem. On short distance where you can see landmarks you could use triangulation. But on long distance where you don't see the land you estimate your relative position by measuring how fast you go and in which direction of current are not too strong. But you will need to regularly correct it using absolute positioning strategies: using stars and time. With the position of the sun or of the stars, you can relatively measure the latitude, usually using a sextant. It does not depends on time because the Earth \"vertical axis\" stays mostly parallel to itself in time (a little bit of precession but it's negligible). With the time you can know how much Earth rotated on itself, and therefore deduce where the sun or stars should be depending on your longitude. Now, the trick is to keep track of time reliably on a moving ship. That's actually the main driving factor for the invention of pocket watches and pendulum-less clocks."
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bvn8kr | Why is it so difficult for games to support a large amount of users on the screen? | Technology | explainlikeimfive | {
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"text": [
"Because raw speed isn't everything. The latency between you and the server, the servers upload rate and the other players ping is important as is packet loss and the games engine may have limitations in displaying too many people causing it to chug and send information more slowly.",
"Each person is another computer that has to submit their location and time data. Every time someone moves an inch in-game, their computer had to tell the server that the move happened, the server needs to update that position, receive a request from **your** computer for the data/locations of any players in < place > at < time > . The actual result might be pretty small. Person A is standing at X; person B is standing at Y, etc, but the problem arises when you've got a few dozen people all moving and interacting in one space, and they all want *constant* updates on the positions of the other players. Oh, and any player can stop and reverse direction at any moment, and the players in question might be hundreds of miles from the server. Light and computer processing only goes but so fast. No surprise then when you get a few players who shift or \"rubber band\" a bit."
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bvnzyy | Why do some large, multimillion dollar companies have so much trouble making a website that works well on mobile ? | Technology | explainlikeimfive | {
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"There are a lot of potential aspects to this, but I'm a software developer who used to work for a giant digital agency making those multi-million dollar sites, and it is insane how much overhead and waste there is with companies that throw that kind of money around. One of my last projects before I left, a company literally paid for me and a team of developers full time as contractors through my agency, which means they were paying at least a few hundred an hour each, for almost 3 weeks, for us to sit around watching YouTube videos while they figured out what they wanted us to work on. Then once you do get to work, there are so many stakeholders and managers with conflicting priorities that it can become nearly impossible to make meaningful progress towards a streamlined product. TLDR: Paying multiple millions of dollars for a website can sometimes net you a pretty mediocre, bloated website with a lot of consultant travel and expensed business lunches.",
"Many of them want to steer you towards the app, which they have more control over and can collect different kinds of data.",
"Those are usually riddled with ads, adware, tracking stuff for future ads and adware etc. Most news sites are now because that’s the only way they can monetize it without subscription fees",
"The management doesn't know shit about websites, they just tell the designer, I want this and that and this and that and these things too, and I want to make money from ads, lots of money.",
"It is difficult and expensive. New web site designs take years, and little of it is affected by skilled programmers. & #x200B; It is very hard to design a web site for multiple stakeholders with differing priorities. And most large companies have a range of priorities. That is because they have multiple products. For example, Apple needs to balance the needs of the iPhone and the Mac products. Chevy has to balance between trucks and sedans. So a \"new\" web design is the start of a lot of internal discussion and that takes time. There is no magic technology that makes all content visible at the same time. & #x200B; Next, the big company designs a site but doesn't have the budget to transfer the content. Or they have the budget, but not the required people, which often must be subject matter experts."
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bvp3s7 | What’s inside those black boxes on circuit boards, and what’s happening inside when the machine is running? | Technology | explainlikeimfive | {
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"Here is a photo of the inside of one integrated circuit. URL_1 This is a very early integrated circuit from the 1950s, the ua741 operational amplifier. It is a purely analog circuit, which essentially is an amalgamation of about 25 transistors and a couple of diodes, resistors and capacitors in a package which is much smaller than could have been done using conventional circuit board construction of the time. So this is about as simple as it gets. A modern integrated circuit will usually have anywhere from 10 times to 1 million times that many transistors. This is a modern ARM micro controller: URL_0 Its manufacturer does not specify the exact number of transistors, but given that it has 96 kB of SRAM and 1MB of Flash memory, it is certainly in the millions. Most likely all of the business of the ARM Cortex-M3 core is in the bottom left corner where you have pink and green colors, and the other 85% of the chip is either RAM or Flash. Around the edge of that Cortex-M3 die you can see square pads (purple on a yellow border). These are the bond pads, which are welded to a frame, which in turn is soldered to the circuit board.",
"They contain different sensitive microcomponents, like processors, capacitors e.t.c. and inside happens the same thing that would happen in bigger electrical components. The black box is just a protective shell.",
"The black boxes are called integrated circuits. An integrated circuit holds a tiny piece of silicon that contains many transistors wired together. A transistor can be considered a switch that can be turned on and off electrically. So transistors can turn other transistors on and off. A modern computer is essentially a billion of these tiny switches, turning on and off a billion times a second. By combining a few transistors, you can make something called a logic gate, that takes some inputs (which are 0 or 1) and produces an output (also 0 or 1). For instance, an AND gate outputs a 1 if all the inputs are 1, and a 0 otherwise. Logic gates may seem trivial, but by combining enough logic gates, you can build a computer. Connecting a couple of logic gates together produces a latch, a circuit that can remember a 0 or 1. A few logic gates can add a number. Circuits can also control other circuits, which is how a computer performs different steps. We had an exhibit at Maker Faire showing exactly what's inside an integrated circuit and how it works (see our [video]( URL_0 )). I also took the photo in /u/PAJW's answer."
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"https://upload.wikimedia.org/wikipedia/commons/thumb/8/89/STM32F103VGT6-HD.jpg/1200px-STM32F103VGT6-HD.jpg",
"http://static.righto.com/images/741/clean_scaled_small.png"
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"https://www.evilmadscientist.com/2019/uncovering-the-silicon-video/"
]
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bvqehp | Before electrics, how did pipe organs work? | I'm aware of the manual bellows to provide air. But how was the keyboard "the manual" connected to the pipes? Modern organs use small electronic air valves at the base of each pipe. The electricity is diverted to the correct pipes by relays depending on which stops are pulled. Before electricity, wires or relays, how did they do this? | Technology | explainlikeimfive | {
"a_id": [
"eprntvp",
"eprojk0"
],
"text": [
"A *lot* of adjoined levers and pulley systems. Before the advent of electronic and digital systems everything was based on mechanical principles. Edit: [here is a YouTube video giving a rough explanation of a mechanical organs innards]( URL_0 )",
"It's called a tracker. The key would physically pull a cable that opened a valve. There are two problems with this. First, this meant that the console really needed to be built into one place, centered in front of the pipes. A modern electro-mechanical system can have the console moved around. Second, you actually pulled more weight the more stops you have on, so having a full registration required strength and could actually cause injury. If the keys on the unplayed manuals move at the same time, that indicates you are looking at a tracker."
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bvqncj | Why are people complaining that the production of electric cars creates more pollution when driving them creates less in the long term? | Technology | explainlikeimfive | {
"a_id": [
"eprqmp0",
"eprt23k",
"eprstv4"
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"text": [
"Because everything can be twisted to suit your own agenda if you only present half the story.",
"Because large amounts of disinformation have been spread by people who stand to benefit from the status quo - a good example of this is [the anti-EV misinformation funded by the Koch Brothers]( URL_1 ). This problem is compounded by the fact that there are a lot of people who oppose EVs because of the stereotypical political leanings of their owners, who were at one point labeled as being excessively concerned with environmental conservation. As a result, those people uncritically accept negative claims against EVs without regard to the veracity of those claims. The same thing [happened to the Prius more than a decade ago]( URL_0 ).",
"Just remind them that the us military complex is the largest carbon polluter in the entire vehicle polluting debate"
],
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"https://np.reddit.com/r/teslamotors/comments/2kou6r/does_anyone_know_what_happens_to_the_batteries/clnlkue/",
"https://electrek.co/2017/06/27/koch-brothers-electric-cars-fossil-fuels/"
],
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bvr2bi | the C computer language compiler was written in C. How did it get compiled if there was no C compiler until it was written? | Technology | explainlikeimfive | {
"a_id": [
"eprydgr"
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"text": [
"The first C compiler was written in B. That sounds like a joke, I know, but it's true. C was originally called \"NB\" for \"New B.\" Dennis Ritchie wrote up the history of C for his website at Bell Labs, which you can read here: URL_0"
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"https://www.bell-labs.com/usr/dmr/www/chist.html"
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|
bvrz27 | Why, after so many years, printers are still poorly designed and constantly run into problems? | Technology | explainlikeimfive | {
"a_id": [
"eps52h3",
"eps5sph"
],
"text": [
"I suspect it's because the profit margins on printers are razor thin. It's the Gillette razor model - give away the printer and make money on ink/toner. But then these days the aftermarket ink/toner does a great job and yet the printer manufacturers have conditioned people to expect cheap printers. & #x200B; Take a look at toner for instance. Especially for a color laser printer. You can get a decent color laser for $150-200 on sale, but when those toners run out you're paying $300-400 for a set! It's literally cheaper to throw away the entire printer and buy a new one.",
"Printer tech here. The reason for most printers jamming is due to crappy paper and/or dirty rollers and improper humidity. The pickup and feed rollers become dirty due to paper dust and more commonly regular dust. This causes the rollers/tires to slip on the paper causing paper to not feed straight anymore. Too dry of paper causes static which causes paper to stick to each other and too humid causes paper to stick to each other as well. There's also engineering involved to have fewer motors, in turn having more clutches and solenoids. Printers are always being built to be faster and faster and smaller and smaller allowing for less discrepancies in paper feed. I hope that answers it enough for you."
],
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3,
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|
bvwto6 | Why aren't iPhone viruses more common? What does Apple do that makes iPhones so secure virus-wise? | Technology | explainlikeimfive | {
"a_id": [
"ept1teu"
],
"text": [
"They don't allow iPhone owners to modify and screw around with their products as much as Google does with Android. The devices are locked down more. Also, they have much stricter quality control requirements for their App Store. The Google Play store deletes harmful apps if they are detected but that doesn't mean someone can't upload something that does something bad in the first place. And you can download programs from multiple places, so you're not even restricted to the Google app store."
],
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bvy0p6 | Why don’t we see devices use B, C, and D batteries anymore? Or the square 9v ones? | Technology | explainlikeimfive | {
"a_id": [
"eptbjfj",
"epte9i1",
"eptg5p6"
],
"text": [
"The energy density and maximum power output of lithium ion batteries, combined with their decreasing cost, makes the idea of using large sets of C/D batteries unattractive. Why have a massive pack of replaceable cells when for a little extra cost, you can have a built in rechargeable battery pack less than half the size?",
"A and B batteries were used in old fashioned tube radios, and had no other purpose once household electric was common. They don't produce much power by weight, an old boombox would have seven or eight pounds of batteries that could only run for a day or two. 9 volts was good for crude electronics, but almost nothing uses voltages that high except things you would normally plug in. Lithium Ion batteries run at 3.7 volts, so that's the voltage most battery electronics are made to run on now.",
"Devices like what? Battery choice/size is dictated by the design and function of the device. Everything today is small and very efficient so instead of 4d cell Maglites we have 2AAA cell LED flashlights that are smaller, lighter, brighter, cheaper and last longer utilizing much less power. Also, phones and other rechargeable electronics will have internal commercial sized Li-ion batteries or can even run off of watch batteries because things are so much more efficient now. We don't see them because of supply and demand. Devices became less power hungry AND small batteries became stronger (Li-ion)."
],
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22,
5
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bw4hfo | Why aren’t commercial aircraft using electric engines? Aviation is a huge carbon emission source after all. | Technology | explainlikeimfive | {
"a_id": [
"epv2k9h",
"epv2hs3",
"epv308b"
],
"text": [
"Batteries are heavy. An electric airliner isn't really an option. They also need to fly frequently, landing to deliver passengers then turning around to take off with more, and recharging an aircraft for ages also won't work.",
"The weight of batteries required to develop the required thrust makes it unviable at the moment",
"Some companies are working on it. For example Heart Aerospace ([ URL_1 ]( URL_0 )) recently raised money to do exactly that."
],
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|
bw55fs | How is a food recipe scaled up for mass production on an assembly line? Is it possible to maintain or come close to the original recipe when it's changed to be manufactured at a factory? | Technology | explainlikeimfive | {
"a_id": [
"epv8mh8",
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],
"text": [
"Absolutely. Cooking is a series of mechanical and chemical processes to turn raw material into a finished product. It can be made and packaged in an assembly-line style factory. Honestly, I'm wondering if there's something deeper about your question that I'm missing. How do you imagine we have things like computers and cars? Why *wouldn't* these processes work just as well for food?",
"If by original recipe you mean the exact ingredients and cooking method, then it is impossible for a factory to simply scale up a recipe used in a kitchen. There are many other factors to consider when making food on a large scale production process. The food itself has to have longer shelf life, be more stable, have consistent texture, color and odor, be compatible with packaging/transport and have a lot less bacteria than what a typical home kitchen environment would produce. A production food recipe will probably have flavorings, colorings, use things like powdered spices, herbs and essences rather than the raw ingredients used in a kitchen recipe. In many cases preservatives, stabilizers and emulsifiers need to be added to improve shelf life. In terms of taste though, a food factory is likelier to be more consistent than a home cook. With advances in food chemistry, the overall taste is likely better or on par with an average home cook but might lose out to what a good cook could produce at home."
],
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|
bw68aw | How do restaurants charge your card for tips after having already run them? | Technology | explainlikeimfive | {
"a_id": [
"epvguah"
],
"text": [
"When they run your card, they are preauthorizing a charge to your card for the minimum amount of your bill with zero tip. They get approval from the card issuer for the minimum amount, but the transaction is left open until they know what tip you left. When they see the tip, they add that to the preauthorized charge and then the transaction is officially closed."
],
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8
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|
bw8qnv | How you can isolate the vocals on a song using the instrumental | Technology | explainlikeimfive | {
"a_id": [
"epvx031"
],
"text": [
"It depends on how the song is mixed, and it generally works better with tracks that are in mono rather than stereo. It’s to do with a thing called phase cancellation - exactly the same way noise cancelling headphones work. You play a sound, and at the same time you play the same sound but with the waveform flipped upside down. The peaks and troughs in the waveform cancel each other out and you’re left with silence. So - if you use this technique with an identical instrumental track, the sound of the instruments will cancel each other out, and you’ll be left with nothing but the vocals. Some recording studios use this technique for playback, so a musician or singer can record without requiring headphones and still end up with a clean, isolated track. Here’s an example of guitarist Tommy Emmanuel doing just that: URL_0 And here’s some further reading if you’re interested in learning how to do it yourself: URL_1"
],
"score": [
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"https://youtu.be/69GXkBOPv_U",
"https://iconcollective.com/remove-vocals-from-songs/"
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|
bw9cuc | How does a store know I'm stealing something? | Edit: to clarify. I'm talking about these vertical things near the entrance, which set an alarm off if you bring something unpaid for close | Technology | explainlikeimfive | {
"a_id": [
"epw0nny",
"epw07xv"
],
"text": [
"I’m not sure if I can write enough words for ELI5: Sensors by the door don’t work for everything, it’s only certain high value items, such an item will have a little strip on them that the cashier passes over something several times to deactivate when you buy it. I guess the strip is probably an RF chip, but I’m not sure. If you try to pilfer something that doesn’t have this tag, the alarm will not go off, but the store may or may not have other loss prevention measures such as people monitoring cameras that would watch you try to steal the other thing.",
"I would rephrase this question to ask how the sensor monitors in stores detect the theft sensors on items."
],
"score": [
4,
3
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bw9gwf | How do speakers work? | Technology | explainlikeimfive | {
"a_id": [
"epw0ic1",
"epw0jw4"
],
"text": [
"I can totally see how this is confusing, it might help to think about a speaker as a reverse ear - they both have surfaces that move with the changing air pressure. Your ear has no problem hearing two different tones at once. The reason this works is the idea of superposition - when you have two tones playing together they add up to make a complicated shape. These tones can be split up by clever maths (fourier transform) or by your clever brain. I guess it's a bit like a pixel on the screen you're looking at right now. There are three 'tones' red, blue and green. When you have multiple of these 'tones' on in the same pixel they mix together to make another colour, but still contain all the information from the base colours, which can be separated from each other. When you see a waveform in a program like Audacity you're seeing the result of adding all these tones together. The speaker follows the waveform shown, but it is built from lots of different tones which can still be extracted. If you do an image search for superposition you'll get a better understanding of how all these different frequency components add together.",
"It sounds like you understand the mechanics of how a speaker works. It simply vibrates in a way that creates a complex wave of energy in the air. If you zoom in on a sound wave in an audio editing program you’ll see a complex shape made up of the additive and subtractive peaks and valleys of multiple frequencies. The speaker creates a wave of energy in the air that looks like that. The magic happens in our ear. That complex wave of air compression and rarefaction is decoded by our brain into the constituent frequencies of that complex wave. Since nothing that I know of in nature produces a perfect sine wave this phenomenon occurs with every sound producing thing... not just speakers."
],
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30,
5
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|
bwbynb | Why are there many gpu manufacturers (zotac, Asus, msi...) but onlz 2 pc CPU manufacturers? | Technology | explainlikeimfive | {
"a_id": [
"epwi7uy",
"epwhv2k"
],
"text": [
"They're graphics card manufacturers, not GPU manufacturers. For the GPU the two largest manufacturers are nVidia and AMD, it's pretty much like with CPU's. They develop and create the GPU. Third party graphics card manufacturers can then make a deal with Nvidia to use their GPU. The GPU design can't be changed, but everything else that's on a graphics card, such as ram or voltage controllers. Besides that, they can increase the MHz of the GPU. If you buy a CPU you already buy the chip itself. There's pretty much nothing, besides overclocking, that a 3rd party manufacturer could change. And Intel and AMD rather sell their own products. I must say though that this only applies for the Desktop/Laptop market. When it comes to other things, such as smartphones, the list of actual GPU and CPU manufacturers significantly increases.",
"It comes down to the stunning cost of being a major CPU manufacturer. The industry is so competitive, you need to build a major new factory every two years or so, and such a factory can easily cost over a billion dollars, and must be supported by an army of extremely advanced design engineers. There isn't room for many companies to keep up with this spending race and still make a profit."
],
"score": [
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|
bwebpl | How do apps like Apple Maps and Google Maps know how much traffic is present on a road? and how do they calculate the destination times accordingly? | Technology | explainlikeimfive | {
"a_id": [
"epwylfk",
"epx3tq6",
"epwz6gc",
"epwz3pe"
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"text": [
"There are many ways. One such way is to buy anonymous data from cell phone companies who track how many of their users move from tower to tower and how quickly. Given the geometry of cell sites, they can tell which users are likely on a nearby highway at a given time and track them as the move down the road and connect to another cell site. & #x200B; They can also use data provided from app users. & #x200B; As for the rest of the question, I can't say.",
"Simplest way doesn't even require cross referencing lots of data. Just look at the app users that are *currently* using the app (who are broadcasting their location) and note their speed given where they are. If they're on a freeway and they're going 15mph (or < 50% of speed limit, or whatever metric you prefer)? Traffic is really bad. As for destination times, since most road systems follow a similar pattern to hub-and-spoke (travelers go from an end node, up to a central hub, then back to the end node), destination time can be approximated by maintaining a node graph and on-the-fly adjusting edge cost based on empirical data. If you know that a 1 mile section of freeway has a speed limit of 60mph and it *should* take exactly one minute to travel down the road at limit, but people are taking two due to traffic, you can feed that data back into the expected destination time.",
"Varying sources. Traditional source is the dept of transportation. They embed sensors in highway pavement to tell how much traffic there is. They publish that data. Second as mentioned is using cell phones to track movement.",
"Destination time calculations are done via algorithms, and the traffic density mapping is done via interface between user base actively using the GPS app, as well as the GPS systems' use of Google's location services on Androids to extrapolate the traffic in a given area."
],
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|
bwhvc3 | How come your car's aircon needs topped up and recharged, but your fridge in your kitchen does not? | Technology | explainlikeimfive | {
"a_id": [
"epxorlh"
],
"text": [
"Your fridge is a pretty well closed off system where all the joints can be firmly sealed, and then it never moves for 10-20 years. Your car has a lot more flexible hoses and seals because it has to move the refrigerant from a compressor somewhere in the engine bay to your AC unit and back, and it does this while the whole thing is bumping and vibrating all the time. Those flexible bits tend to wear out over time and stop doing a great job of keeping the system sealed, so some refrigerant leaks out."
],
"score": [
13
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|
bwitm6 | How do polarized lenses work? | I noticed while driving with my polarized sunglasses that if I rotated my head on a vertical axis, it would get lighter, then go darker as I orient my head normally. How does that happen? And why does everything seem 'crisper' in them? | Technology | explainlikeimfive | {
"a_id": [
"epxwfao"
],
"text": [
"Waves have a direction to them. Tldr:. Waves have a direction that they vibrate like up and down, or side to side. Polarized lenses essentially filter away one \"direction\" of the wave. It's easiest to imagine ocean waves, as they go up and down as they cruise along. If you put a barrier in the way you'll stop the waves, this is normal tinting on sunglasses. If you put a gap in the barrier you might let the waves through. If the gap was up and down waves could get through easily (they also go up and down) If instead you left a horizontal gap, or a slit, in the barrier you'd still stop the waves, as they can't fit through. They will also up against the roof and floor of the gap and be stopped. Polarized glasses use this to help reduce glare. Light can have it's wave go any direction at all. But when it strikes a flat surface, like a car hood, windshield or even the road it polarizes the light. Any light that was vibrating the wrong way gets squashed as it stands against the surface. If it was vibrating the right way (along the surface, instead of into it) it'll survive and bounce off. You polarized lenses have super tiny slits in them that will block light that is vibrating \"horizontally\" as that is the light that bounced off objects that tends to produce glare. So they squish that light out, helping by not just dining all light, but eliminating light from sources that give strong glariing reflections. As for making things crisper, this is because it removed some light based off of an objects surfaces and edges. This helps creat contrast with the surfaces that weren't filtered, helping you see it better. Some animals can naturally detect polarization! A couple other fun things to try:. Look at a phone or computer screen and turn your head sideways. LCD screen are highly polarized, and sometimes the colors are different directions. Looking at a clear blue sky with polarized glasses should show you a darker band crossing the sky, where light reflected from the air itself is polarized. Hold two pairs of polarized glasses so you can see through them both. Rotate one so it's 90' to the other."
],
"score": [
8
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bwj9qw | What is the purpose of different processors on the same phone? | I looked into the Galaxy S10 series recently and I saw that the US version uses the Snapdragon 855 while the International version uses the Exynos chip and there is a difference between those two chips in terms of performance. What is the reason behind that? | Technology | explainlikeimfive | {
"a_id": [
"epy0b79"
],
"text": [
"Samsung has a contract with Qualcomm to use their chips in the United States. Do some research on it as it's kinda interesting! They've been locked in with Qualcomm for a long time. Everywhere else samsung produces their own Exynos chip."
],
"score": [
8
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"text_urls": [
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} | [
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bwltei | How does telephones actually work? How can someone in other part of the world hear my voice or sounds through the telephone with almost no delay? | Technology | explainlikeimfive | {
"a_id": [
"epygc6e",
"epyh6iq"
],
"text": [
"Old school telephones are little more than a couple of microphones and a couple of speakers connected by wire. The mouth piece of each telephone is a microphone. The microphone converts sound into an electrical signal, which can travel very quickly along wires. That signal gets fed into a speaker in the ear piece of the other telephone. The speaker converts the electrical signal back into sound, and the person on the other end hears the whatever was said into the other telephone. You know those old school switch boards? The ones where operators seem to be randomly plugging cables into a bunch of holes? They're literally plugging in the microphone/speaker pair of one phone into the corresponding microphone/speaker pair of another phone so two people can talk.",
"The telephone networks are a lot like the internet in most ways. When you dial a phone number the phone tries to connect to the phone at that number, your phone company works out if you are allowed to make that call or not, and then your phone breaks your voice down into little digital packets and sends them to the destination. To get to the destination, the packet has the source number (your phone) and the destination number (who you are calling) and gets sent to the first hop (the phone exchange). Based on the destination the exchange then works out which is the next exchange that it knows about that is closest to the destination number and sends it on. That exchange then either sends it on to a closer exchange, or if it is the closest one sends it to the destination phone. The other phone then takes those packets and turns them back into sound and does the same with the voice of the other person."
],
"score": [
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5
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|
bwmv6x | How does Tesla Autopilot work? | I know it has something to do with sensors and software but not much else. | Technology | explainlikeimfive | {
"a_id": [
"epylzm9",
"eq1pxc0"
],
"text": [
"It is as combination of a lane-keeping assitant, and radar guided cruise control (except it doesn't use radar, it uses cameras, I THINK). That's pretty much all it is. I know it doesn't like working when there are no white lines to define the lane. It has cameras in the pillars between the front and rear doors for the lane-keeping aspect. And we all know it has had troubles *seeing* things in front of it (trucks, concrete barriers). If it had the actual radar guided part, it wouldn't hit anything. For what it's worth, [plenty of other companies have the same sort of technology]( URL_0 ), but they just don't like to call it *autopilot* for the obvious reasons of it being dangerous and so on.",
"You can look at Tesla’s autopilot in two ways: highway autopilot and full autopilot. Currently, Tesla’s use sensors and cameras to read the lines on the road, knowing how to stay in lane without the driver touching the wheel. The next step, and the largest breakthrough in driving, will be full autopilot. Using cameras and computers to see a stop sign up ahead and the computer knows to stop there. Or seeing green in the stop light and knowing it’s safe to keep driving. This is done by thousands of Tesla’s on the road today gathering data and the machine computer constantly learning “oh okay so that’s a stop sign. That’s a yield sign. That’s a yellow light.” Then applying what to do when your car sees it."
],
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} | [
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bwn1s6 | How is blurring added to photos and videos and how can be removed? | Technology | explainlikeimfive | {
"a_id": [
"epymudm"
],
"text": [
"Natural blurring in photos and videos is from the focal point and depth of field. This cannot be removed. Blurring by software can be altered but will be different in case by case scenarios."
],
"score": [
5
],
"text_urls": [
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} | [
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|
bwnikc | In what situation would someone need 1.5TB RAM | Technology | explainlikeimfive | {
"a_id": [
"epypk2n",
"epyps2d"
],
"text": [
"High calculation applications. 3d design, animation, computational dynamics, physics simulations",
"Database servers love RAM. So all you need is a database with more then 1.5TB of data and you make your database faster by putting so much ram in the system."
],
"score": [
20,
7
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"text_urls": [
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|
bwoi65 | Why do movements in video games look so overly "smooth"? | I noticed this again recently when I was watching [this cyberpunk 2077]( URL_0 ) trailer. What is the reason for this unrealistic "smoothness" in the characters' movements? Surely it should be possible to add more realistic jerky, abrupt elements? Are there techological limits or are the reasons for not doing that artistic? | Technology | explainlikeimfive | {
"a_id": [
"epzdtvi"
],
"text": [
"Former game dev here, & #x200B; There is actually a really big problem: the uncanny valley. In aesthetics, this refers to the degree of an object's resemblance to human appearance and your emotional response to it. In short, the closer we get to making something human, the more your mind and emotional response is aware that it's not real, and you have an adverse reaction. & #x200B; It's creepy as shit. Like touched by your uncle, who's made of spiders creepy. & #x200B; You have to actually get it flawlessly perfect, or it's wrong. So it's easier to stop at 80-90% there rather then go up to 98-99%. Your mind knows that these images aren't real, and so it stops the uncanny valley. & #x200B; And in in video games, they're not aiming for realism anyway."
],
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7
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bwpr30 | how do Android phones get slower over the years? | Technology | explainlikeimfive | {
"a_id": [
"epzbed5"
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"text": [
"The phone do not get slower but is is the software that is updated and newer version in general have more feature and require higher performance/memory on the phone. New software and OS is designed to use You often add more and more software where som it it run in the background so the phone have more to do more. So use a some app to see what program is active in the background and uninstall them if you no longer use them or just disable them in the apps settings. This can have a hug effect as you free up both memory and cpu usage. Other reason is that your baseline of speed is different and you might compare to other faster phones. If the storage on the phone is full it might preformae slower so remove apps you do not use and put photos, videos etc on a computer and in the cloud. If you did a factory restore to the original software it would be as fast as when it was new but slow down when the software was updated. & #x200B; The thing that age in a phone is the battery and the capacity and max current drop over time. So it might be the case that the the phone cant run the CPU at as high frequency with a old battery especially if it is not fully charged. Apple have done it because som old phones they could shut down when the battery was at 40% but with the change the could use all power in the battery but at lower speed. It might be the case that some android phones does that do So old bad batteries might reduce the performance on a phone but I am not sure that any Android phone does that. It is the only change that would not fixed by a software."
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bwt1sn | How do thermometers work and how do they calculate what "it feels like." | Checking my phone for the temperature, I see that its currently 91 degrees but it feels like 99. Got me wondering how thermometers work/how they came to be and how they calculate "what it feels like." | Technology | explainlikeimfive | {
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"Thermometers often exploit the fact that materials expand/contract depending on temperature, and different materials do it at different rate. The \"feels like\" temperature is a mix of the real temperature and the humidity. Humidity decreases the ability for sweat to remove heat from the body, so it makes the body heat up more than the same temp with low humidity.",
"for digital thermometers: some materials change their conductivity based on temperature, so forcing electricity to flow through this material and seeing how that electricity changes tells you the temperature the material is experiencing.",
"Humans cool ourselves through evaporative cooling. We sweat, the sweat evaporates and takes substantial heat with it. The ability for water to evaporate depends on the temperature, the relative humidity, and the air pressure. A \"dry\" 90 F means water evaporates quickly, while a wet 90 F means water does not evaporate well. The wet 90 F feels much hotter to humans. The classic way to measure this phenomenon was with a thermometer with a wet cloth wrapped around it. This gives you the wet bulb temperature, which will be below the ambient air temperature. Even in places that reach 110+ F, nowhere on earth ever reaches a wet bulb temperature above 100 F. In fact, sustained exposure to wet bulb temperatures in the 90 F range is highly fatal. The most comfortable weather has a wet bulb temperature around 60 F or lower. The most miserable/hot places on earth tend to be in the mid 80 F range. 90+ is very rare. The heat index is the \"feels like\" temperature and is based on this concept."
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bwwcsn | why are some of the Waybackmachine snapshots links broken/missing? | Technology | explainlikeimfive | {
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"text": [
"There are many possible reasons. Maybe it was missed in the copy, or lost along the way to archiving. Some things have been removed through court orders or other legal actions. Maybe it was hosted on a different site, and that site had different robots instructions which led to it not being archived. There is no way to know which."
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bwwd2v | What are apertures, f-stops, How does depth of field work, and how does lens measurement factor into the equation? | Technology | explainlikeimfive | {
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"An ideal lens focuses light from a single plane (called the focal plane) onto its sensor. However, that's not super useful, as we often want to take pictures of things that are thick. As it turns out, there is a region around the focal plane where the image is still well focused. This is called the \"field\" of the photo, and the \"depth of field\" (DOF) measures the thickness of this region from the point nearest the camera that is well focused to the farthest point that is well focused. As it turns out, actual lenses are not ideal lenses. This matters when it comes to DOF. At small apertures, much less light enters the lens, and it all enters through the middle part of the lens. The result is a larger DOF. In fact, you can make pictures with no lens at all using a pinhole camera. The aperture is so small that the DOF is essentially infinite. Since the amount of light that comes through is similarly small, you need a very bright scene. Since aperture effects both amount of light and DOF, it's not exactly a DOF control. As less light comes through, more integration time (or exposure time if you're still thinking of a film camera) is required to get an image. f-number (or f-stop) is a ratio of aperture to focal length. This is a camera-specific idea, but the exposure time for similar f-stops is similar. This was a more interesting parameter when light meters were separate from cameras. Almost all modern cameras use through-the-lens metering and automatic (or at least semi-automatic programs) to select appropriate f-stops and exposure times."
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bwwsf1 | Can a phone call last forever (or at least until the phone itself deteriorates beyond function) if the phone stays plugged in to it's charger? | Technology | explainlikeimfive | {
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"text": [
"I'm not sure if this applies to mobile phone networks, but way back when in the dark ages of technology (mid-90s), we had a single local phone company competing with BT, the national supplier. As a way to try to grow quickly, they offered innovative special offers, amongst them free local phone calls, something unknown in the UK until then. Sadly for them, no one in their marketing team had apparently heard of modems and BBSes. After 4 monthly phone bills with individual call lengths in the hundreds of hours, they quietly slipped a rule in to limit calls to 24 continuous hours each :)"
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bwwwwk | How does a Minecraft computer work? | Like how does it have memory, and be able to run applications and and what sort of functions can they do and how? | Technology | explainlikeimfive | {
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"text": [
"Minecraft has something called redstone, which is able to simulate most logic circuits and electrical circuits. So you could theoretically build anything electronic that doesn't include audio or video circuitry. (Although there are sound blocks, so there is a limited midi type music capability.)",
"Computers work by performing mathematical operations (addition, subtraction, and so on). However, computers don’t understand numbers as us, they translate our numbers (decimal numbers) into binary numbers (1s and 0s). For example, the number 4 is 0100 in binary. So, the computer needs an input from the user to make these calculations. What they do in Minecraft is utilize switches to represent those 1s and 0s. Then, the player creates the logic gates (the physical parts of the computer that carry the inputs) and then the Minecraft computer is able to come up with an answer"
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bwy7sk | Why is it hard for phone companies to supply unlimited high speed data? | Technology | explainlikeimfive | {
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"text": [
"It’s not. They just like money. It’s the same reason the cable and internet companies are fighting to prevent cities from installing their own fiber optic lines, they want more money.",
"It’s not hard for them to do. They could give you great speed all the time. By imposing limitations on the speed and data usage, they can charge more money and increase profits.",
"Hundreds to thousands of phones share a single base station (a \"cell\") which sends data to and from them using a limited range of radio frequencies. Its capacity is limited. If everyone decides to watch Netflix on their phones all day, the carrier needs to install many more cells, at great expense."
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bwzofa | How do ones and zeros make up complex computer programs???? | Technology | explainlikeimfive | {
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"Like you're 5? I'm not sure I can pull that off, but I'll cover what I know and maybe that will help you. tl;dr: You build something basic to accomplish something basic. Then you put some basic things together to get something advanced, then you put some advanced things together, etc. After a dozen layers of this, you get something very complicated, built upon something very simple. **Physical Circuits, or how to get to basic logic.** At the bottom of the stack, we have the physical circuits of the computer. This is where the 1's and 0's are actually located. The 1's and 0's are actually just if a particular wire has more (1's) or less (0's) current on it. These wires connect to little switches, called transistors, that do something depending on if a wire has enough current in it. These transistors are grouped together into integrated circuits, which is where we can begin to do basic logic with the computer. Next are gates, which are integrated circuits of transistors that accomplish a specific task. For example, an \"OR gate\" is an integrated circuit that will put out a 1 on the output wire if either of the wires that are connected to the input side of the circuit are carrying current signifying a 1. There are a lot of gates that get more complicated to accomplish different things. Several that come to mind are AND, NOT, NAND (NOT and AND), NOR (NOT and OR), EOR (Exclusive-OR), and ENOR (Exclusive-NOR). After that, groups of these integrated circuits are put together into more complex circuits like an \"adder\", which just adds numbers together. This is accomplished by putting several to hundreds of gates together, and do something helpful really, really fast. Multiple kinds of these complex circuits are usually put together into a single processor, and someone like Intel or AMD writes a software language to control all of these circuits. **Machine Code, or the stuff no person writes in directly anymore** AMD, Intel, or any other processor manufacturer has to write a way for software to talk to their processor. This is can be called an \"instruction set\", but no one will check if you remember that. Several currently popular examples are x86, x86_64, and ARM. This kind of code is extremely picky, so most programmers rely on another program to write this code for them. **Low-level software languages** Next up the ladder is the low-level languages, like Assembly. These are languages that were originally designed to be much easier for humans to read and edit than machine code, even though they really aren't thought of as easy anymore. Programs written in these languages are still tied to a specific processor, or at least a particular instruction set. These languages need to be re-written into machine code before they can actually be run, so programmers wrote other programs to read these programs and translate them into the commands that will actually be sent to the processor. **High-level software languages** High-level languages are languages that run on almost any processor. Examples include C, Java, and BASIC. The real power of these languages is that humans can easily read them and understand what is going on at any given step. These languages still need to be run through other programs (sometimes several!) before they can actually be used by the processor, but that is a small price to pay for the time saved for the programmer.",
"I think this is too general to explain simply without a massive wall of text. [This]( URL_0 ) was what made it all click for me. Basically, any instruction is represented as a series of ones and zeroes, that say \"go do these operations\". You have a lot of choices, and can do a lot of instructions in order. Basically, as long as you could write it down, even things like \"if this, do that, otherwise, go here and continue\", are represented with these 1's and 0's in the instruction that a CPU executes. Specific implementations of that are covered in the link above, but the short explanation is the CPU always computes every outcome simultaneously, and some of the 1's and 0's are selectors for which outcome to choose. You could think of it like if you gave me two numbers, and if I had circuits that did binary addition and subtraction, I could select which one of them I wanted to use with a 1 or a 0. Complex computer programs are really just a bunch of layers of simple programs, built from the building blocks above, that make them seem complex as a whole, but individual pieces generally don't do very much.",
"Computers perform tasks based off of electrical signals sent to each part to do a certain thing. The ones and zeros simply mean electricity is on for one and off for zero.",
"Although it only has 1s and 0s a specific combinations of 1s and 0s represents a letter, or a command, for instance \"a\" is 01100001. so it works a tiny bit like Morse code.",
"The same way only 26 English letters and a few punctuation marks can make up a complex work of literature like War and Peace: we use combinations of 1s and 0s to form simple commands, the join those commands together into small, reusable routines, then use those routines to build more and more complex programs.",
"You can think about it like an essay, or a book. You're focusing on the letters, the 1s and 0s. In English, the letters make up words, like how 1s and 0s make up specific machine instructions. When you're writing an essay, you don't think about the individual words, though. You think in terms of sentences and how they connect together to convey the overall message. This is what a programming language basically is, a large collection of \"sentences\" which are each composed of who knows how many machine instructions. As programmers we string those sentences together to write programs. Other programmers think about the machine instruction set and programming tools, and try to make them better at doing their job of giving us useful and coherent sentences to work with. But most people don't write \"big complex programs\" with machine language and no one understands exactly how it all works. Some people use machine language to construct words that other people then put together into sentences, and the rest of us use those sentences to make programs."
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bx55y0 | Why does the quality of GIFs, pics deteriorate with each repost? | Technology | explainlikeimfive | {
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"If you simply copied the link to the original gif it would be fine. If you downloaded the original file and uploaded it to a service that doesn't apply any postprocessing it will be fine. But what typically happens is, when you upload the image to a hosting service, that service decides to process the image to make it smaller or faster or a different file type. Then someone downloads that processed image, reuploads it again to a new host that also applies processing to the image, reducing the quality of the file **again**. Image hosts don't want huge lossless super high res gifs because it costs bandwidth and that costs money. So they mostly try to cut corners by resizing or shrinking the file."
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bx6t6w | How a laser can improve/correct someone's eyesight. | How does laser eye surgery actually work? Which part of the eye are they working on and how is a laser the tool of choice? | Technology | explainlikeimfive | {
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"text": [
"I've had lasik. Basically removes the top (bad) layer of your eye so you can see clearly again.",
"Your eye works kind of like a camera. It's got a lens system that focuses light onto the retina, the part of the eye that senses light. If the lens system is out of whack, the light doesn't focus right, and your eyesight is blurry. One way to correct this is to put another lens in front of the whole thing. That's glasses or contacts. Another way to fix it is to change the lens system of the eye itself. The shape of a lens is very important in determining how it will focus light. Change the shape, change how it focuses light. With laser eye surgery, they don't change the lens itself. They change a layer of tissue in front of the lens, called the cornea. To the best of my knowledge, the laser very precisely burns away parts of the cornea to change its shape. Here's a link with lots of information: URL_0 You may be most interested in the section called \"During the procedure\"."
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bx8p1w | what’s a reference monitor and what’s it for? | Technology | explainlikeimfive | {
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"text": [
"Suppose the animator decides to make a character red. A specific red. Ferrari red. If some other monitor shows this color wrong as a cardinal red, it's very hard for a group to know who has the right color."
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bxc5wf | why do computers connect better to shoddy internet connections when phones and tablets don’t do well? | Technology | explainlikeimfive | {
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"text": [
"If you're talking about LAN connections then it will always be faster than a wireless connection as it is wired and transmits data without much interference. Even if you put wireless cards in your desktop or use laptops it will still be faster than phone using the same wireless connection because they have bigger cards with better reception."
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bxe4n2 | The purpose/use of the speculations of computers/laptops. | I've always just seen the most mainstream processors or the most popular graphics card to use but little do you know, I have no idea what their functions are and their purpose. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"If you're talking about [speculative execution]( URL_1 ), its purpose is to speed up processors. Processors are actually doing many things at a time in a process called pipelining. A common analogy is [laundry]( URL_0 ) - if you're trying to do many loads of laundry in one set of machines, you could wash, dry, and fold an entire load before moving on to the next one, but then you'd be wasting time. To speed up the process, you can wash one load, and then once it's drying start washing the second load. Because you have multiple resources available to you, you can cut the total time to do your four loads of laundry by having multiple things going on in parallel. Processors do this because, most of the time, it lets you speed up the processor by a lot. Instructions are broken into pieces (e.g. get the instruction, do all memory operations, do all arithmetic operations, do all write operations). By allowing multiple instructions to be happening at the same time, you can have each sub-step be faster, allowing you to increase your clock speed. However, there comes an issue when instructions depend on past instructions. For example, if you do one thing when some value is positive, and something else once it's negative, you have to first wait for that value to be calculated before deciding which action to do. One solution is just to leave a gap in the pipeline, and waste a few cycles. Naturally, CPU designers didn't want to do this, and this is where speculative execution comes in. The CPU makes an informed guess of what the result will probably be, and then starts doing those actions. For example, it'll just guess that the value turned out less than 0, and goes on to do that. If the prediction was correct, great! The speculative work turns out to have been useful. However, if the prediction was wrong, the CPU has to switch tracks, and throw away the work. We lose those cycles, but on average we'll be doing faster than if we had left the pipeline empty, so it's a net win. The better the prediction, the better the win. What researchers have recently discovered is that this work was not fully discarded. It turns out that the CPU, while doing the speculation, left behind small traces that could then be used by the program to extract information it shouldn't be allowed to know. It takes advantage that a lot of protections are built into software, while the speculation happens on the CPU, bypassing protections in the software until the program 'catches up' to the speculation."
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bxh56r | subnet mask in networking | Trying to understand what a subnet mask is in a networking crash course for work training. Please help 🙏🏼 | Technology | explainlikeimfive | {
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"An IP address describes 2 things: a network, and a specific host on that network. You can think of it like a first and last name, which describes a family and a specific person in that family. The subnet mask is like the space between the first and last name. It specifies which part belongs to the family, and which part belongs to the individual. John Doe is a specific individual John in the family Doe. If we move the space all the way to the left so that the name is \"J Ohndoe\" you'll notice that now there are only 26 unique names available for members of the Ohndoe family. If we move the space all the way to the right so the name is \"Johndo E\", we can come up with a lot of individual names but only 26 possible families. The subnet mask is used like the space so that we can adapt to situations where we either need a lot of unique individuals and only a few families, or else a lot of families and each family only has a few individuals.",
"Networking is similar to the telephone system. In the US/CAN telephone system, you have an area code and a phone number. The area code indicates the general area of the country you are in, the phone number is the actual phone you are calling*. IP addressing has the same concept, the \"network\" is like the \"area code\", and the \"host\" is like the \"phone number\". In the phone system, the number of digits in the area code is fixed at three, and the phone number is fixed at seven**. In networking, the concept is the same, but the number of \"digits\" you can use to specify the \"area code\" can be different. The system we use today is called CIDR, which stands for Classless Inter-Domain Routing. In CIDR, you can create a network that has any number of bits as the network (except 1). The subnet mask is used to indicate how bits in the 32bit address are used for network, and how many for the host. The subnet mask is usually described in one of two ways: * Dotted decimal notation (255.255.255.0) * slash notation (/24) These both represent a 32bit binary number where the first 24 bits are one and the last 8 are zero. All subnet masks must be all ones on the left and all zeros on the right (except /32, which is just all ones). So, 255.255.255.0 or /24 looks like this: 11111111111111111111111100000000 By the way, 255.255.255.1 would be wrong, because the mask would look like this: 11111111111111111111111100000001 and it violates the rule. Left side is all network and right side is all host (except /32 where the whole thing is host, even though the mask is all network... don't ask) Example: On my router, I say interface Ethernet0 has an IP address of 10.0.0.1 255.255.255.0 (or 10.0.0.1/24) This means, 10.0.0 is the network, and .1 is the address. That network can support 10.0.0.2-10.0.0.254 as other hosts, and 10.0.0.255 would be the broadcast address. If I were to choose 10.0.0.1 255.255.255.128 (or 10.0.0.1/25 or 11111111111111111111111110000000) the router is 10.0.0.1, the hosts can be 10.0.0.2-10.0.0.127, and 10.0.0.128 is the broadcast address. You can look up CIDR on Google to find charts of all of the different combinations of networks you can use. *I know that the first two number of the phone number are the exchange, but I am simplifying to make the analogy better. **The \"+1\" is also not relevant to this discussion. EDIT: Appendix 1: Why \"classless\"? Was there ever a \"classful\"? Yes. When IPv4 was first created, they had a set of fixed ranges of IP addresses that were assigned for different purposes. Some of the ranges had fixed network lengths: * Class A: 255.0.0.0 or /8 (0.0.0.0 through 127.255.255.255) * Class B: 255.255.0.0 or /16 (128.0.0.0 through 191.255.255.255) * Class C: 255.255.255.0 or /24 (192.0.0.0 through 223.255.255.255) * Class D: Reserved for Multicast (224.0.0.0 through 239.255.255.255) * Class E: Experimental (240.0.0.0 though 255.255.255.255) This is why you might hear someone call a /24 network as a \"full class C\"."
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bxiwgq | What are hypersonic missiles ? | Technology | explainlikeimfive | {
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"text": [
"Missiles that travel faster than Mach 5. Supersonic is faster than the speed of sound up to Mach 5, then Hypersonic is above that."
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bxj882 | How does the Turing test work, and why is it still debatable whether it has been passed or not? | Technology | explainlikeimfive | {
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"text": [
"Simple. You are put in a room with a 2 keyboards and 2 screens. On one end there is a person, on the other, a programm. You ask both whatever questions you want, for how long you want. The person is not trying to trick you. If you can't figure out reliably which is the computer and which is the person, the programm has passed the turing test",
"There is no one \"Turing test\". To understand why people talk about it, quick history lesson. At the time computers were being envisioned by early pioneers, we had this idea that machines should be able to do computations. But what is computation? Multiple people, among them Turing, had their own idea of how to rigorously define what is computation, to have this theoretical background that makes sure computers can do any computation. Turing machine was Turing's answer to this, and they formulated cool Turing-Churchill conjecture saying that yeah, this Turing machine idea probably encapsulates what we mean by computation. Anyway, in this world where people are trying to define what computation even means, people wanted to know if these computation machines could think. And lots of philosophical debates started. What does thinking even mean, how do you detect presence of thought, is human brain uniquely capable of thought... And Turing came up with this simple test to direct people towards something practical instead: if you cannot tell the difference between words produced by a computer that may or may not think, and words produced by a human, does it matter if computer thinks or not? From your point of view, it shouldn't matter. So Turing simply proposed, lets test that then to see if computer thinks, if you can tell the difference. For the most part, Turing test obviously has not been passed. You cannot have free-form discussion with a computer without illusion of thought shattering quickly. But if you restrict the test or scope of questions or length of interaction, you can get fairly good results for computer. And the thing is, there is no One True Turing Test. Turing test is an idea about testing humans and their ability to differentiate computers from humans rather than trying to assess computer thought directly. It doesn't have one set of rules, you can do tests in that spirit in multitude of ways, and people have done so. All that matters is that ultimately a human is tasked to tell the difference between a human(that presumably is capable of thought) and a computer(the supposed 'unknown') from their output alone."
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bxjgx0 | How did people construct wells before modern drilling and how dangerous was it? | Technology | explainlikeimfive | {
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"Dig with a shovel. I've got an open well on my property that my great grandfather dug. He dug it with a shovel and shored up there walls with sandstone creek rocks as he went down. Some of the best water I've ever tasted. It's about 4 feet in diameter and 30 or so feet deep.",
"[Here is a video of a hand dug well using bricks to reinforce]( URL_0 )",
"My Great Great (etc) Uncle helped dig the [Big Well]( URL_0 ) and its, well, a big well. Shovels, and a lot of time. I’ve been to the bottom of it a handful of times when I was a kid.",
"In some places, with [lots and lots of stairs]( URL_1 ) and to keep the water safe from people with poor balance or a fear of heights or drowning, [no guardrails]( URL_0 ). I wonder how many slinkies are at the bottoms of those.",
"For a very early oil well I was told about a manual technique, like a heavy weight on the end of a cable. You build a tripod over the top of the well, hauled the weight up by winch and dropped it to impact the rock you are drilling through. Slow, laborious and no directional control. If the impact head came off the cable you had to fish for it with hooks and more cable."
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bxjkxe | why do digital numbers bounce? | ELI5: When I’m chewing something crunchy, like Captain Crunch why do the numbers on my microwave bounce? | Technology | explainlikeimfive | {
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"The numbers on the microwave aren't solidly lit, they blink really fast. They have a high enough refresh rate that you can't tell under normal circumstances. When you chew something crunchy, the crunching is shaking your head and making that refresh rate more visible, so it leaves a sort of \"trail\" imprint on your vision.",
"Many LED numbers and LCD displays do not glow constantly, but blink rather quickly, refreshing the image. When your eyes vibrate, you perceive these series of images as bouncing around because the position of your eyes changes slightly between images.",
"They're right. Led displays blink very fast, but not enough to not being unnoticed. This is because those numbers just can't be displayed contemporaneously. Imagine a display of 4 digital numbers: in the first instant the first number is turned on, while all the others are turned off; in the second instant the second number is turned on, while the others are turned off; In the third instant the third number is turned on, while the others are turned off; ecc. This happens because those displays can only bring in output one value, so if you set a number, display it, then change it and change the digit that should be turned on, at high speed they all look turned on."
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bxknyq | What is the CoC controvery in the Linux community? | Technology | explainlikeimfive | {
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"A touch of relevant history: A contributor on the Opal project made inflammatory remarks about trans people. A trans activist named Coraline Ada Ehmke caught wind and originally tried to get the contributor removed from the project; project leadership compromised to instate a code of conduct. Coraline herself wrote it, I believe, which implies she agreed with the compromise and settled. & #x200B; Thus, the Contributors Covenant was born. & #x200B; Not satisfied, with what she agreed to, Coraline then tried to modify the CC to attack the contributor she originally targeted, and Opal and Coraline seemed to part ways about the issue. & #x200B; Linus recently signed the CC into the Linux kernel, apologized for past behavior, and took a break. The rumor mill took off speculating the cause. & #x200B; Coraline then fanned the flames by engaging in activity she would otherwise detest if it were specific to trans people. She gloated that the Linux kernel project was infiltrated by SJWs and celebrated its demise. She has admitted the CC is a political document, which the Linux kernel contributors almost universally agree has no place in the project. & #x200B; So none of that helps. & #x200B; This lead to one big half of the discussion in that who has a right to be heard in the Linux kernel community if they're not themselves contributors? Coraline makes misconduct personal and seeks to subvert and destroy not the bigotry itself, not even just the person, but everything the person ever touched. She's seeking to destroy the Linux kernel out of pure spite and satisfaction, and is thus toxic in her own way. & #x200B; Coraline is also against meritocracy, where one is rewarded for their contributions. She believes people should be merited for their humanity, because, you know, it doesn't matter how good your code is so long as you're writing it. Or some shit... & #x200B; Some people just want to watch the world burn. & #x200B; But the other half of the discussion is whether the community needs to police itself at all, and that's a subject I don't feel like commenting on.",
"CoC = Code of Conduct. So, Linus has been known to have a temper, which he occasionally would unleash on various people. Usually for good reason, but still, he went further than was really necessary, and has no doubt driven away people who could have made useful contributions. There was some sort of issue surrounding Linus' attendance to a summit with a select group of developers. Linus either misunderstood something, or pretended to misunderstand where it would be to skip the meeting, or tried to intentionally miss the meeting in order to let people discuss his possible replacement. This part is a bit confusing, so I'm not really clear on it. So at the time he traveled to the wrong country, and said \"Well, do the meeting without me, then\". The meeting then got moved to where he was instead. And after that apparently somebody had a big talk with Linus, leading to him having a realization of \"I'm a bit of a jerk\", and deciding to do some self-improvement. Following that, a Code of Conduct got posted. Pretty much instantly conspiracy theories started flying around because some people didn't like the author of the document, and thought it'd institute witch hunts, unpleasant rules, and have the effect of decreasing code quality. IMO it's mostly of a tempest in a teapot as so far nothing horrible has happened as far as I know. But Linus went on a vacation, the document got dropped into the kernel, and nobody hung around to clarify anything, so conspiracy theories started breeding. I think a move like that needed somebody hanging around, talking to people, and shooting down crazy theories."
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bxlk9l | The Internet isn't a physical web of information, so what is it? | My Papaw asked me how the internet worked once, and I really couldn't give him a straight answer. This man believes the internet is a physical tangible web of information up in space that astronauts can just go to anytime they want. Please help me enlighten him! | Technology | explainlikeimfive | {
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"It's a network, connecting other networks, hence the name. Through these networks email and web page requests can be relayed from your personal computer to a server computer providing services you desire.",
"The internet is computers talking to each other with all the conversations routed physically through cable or wirelessly using radio waves. Internet traffic has a 'to' and 'from' address. DNS is like a phone book.",
"Hmm, & #x200B; So, since he's an older person, I'd explain it like calling someone back in the day. & #x200B; You pick up your phone (your computer) and call the switchboard operator (accessing your browser). You tell the operator who you want to talk to (URL), and the operator will transfer you in to proper organization/person (server with the files you want). & #x200B; This is a very dwindled down version of what's happening, one that I think an older individual would be more open to understanding."
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bxqio8 | When switching from one WiFi to another, how come it shuts off the internet while switching, and can’t pass it over without an interruption? | Technology | explainlikeimfive | {
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"That's because your device has to \"prep\" a lot of configurations such as encryption keys, protocols etc. Think of it as switching the battery in your car, you first gotta unplug it, check which wire goes well, reassure you did it correctly and then proceed to turn your car on. It took you time to do all that, you really can't just instantly switch the power supply of your car.",
"its possible to have multiple wifi routers/access points setup on the same network and have no disruption. & #x200B; if you are changing to a new external IP, you need to successfully authenticate on the new network, get a new ip on the new network, the router needs to add your mac to its address book, and then you can start resending packets that havent been responded to. & #x200B; To have no interruptions, internet DNS servers would have to know where you are going BEFORE you switch, so they could anticipate and send packets to the new router, which of course is a new route. afaik that doesnt exist yet. this COULD work similar to when you move, you need to tell the usps where youre going BEFORE you move if you dont want an interruption in mail service. & #x200B; with the internet, it would simply take too many resources to manage and what happens if you decide to connect to starbucks wifi instead of pete's? just a bunch of wasted traffic. much more efficient to have a small delay and know exactly where you are, than where you think youll be."
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bxsl8p | What is white noise? | Technology | explainlikeimfive | {
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"Radios have an \"automatic gain control\" (AGC). When the reception is weak, the circuit that deals with the radio frequencies turns up it's amplification to try and get the best signal it can so it can then extract what actual audio it can. When the gain goes up to maximum, all it ends up amplifying is noise, radio interference from outside and random electrical noise generated inside the circuit components. There might be a weak signal hidden in the noise so you may hear a noisy radio signal as well, so it wouldn't just cut out.",
"White noise is a random signal with equal intensity at every frequency... It’s basically every sound at once. So, for a human being who’s hearing range is 20Hz to 20kHz, when you hear white noise, you’re hearing all those frequencies at once at the same “volume”. Because of the way human hearing works, some frequencies are more intense than others at the same volume, 2kHz to 4kHz especially. So you hear a pretty annoying hiss sound that also seems to rumble. A related type of noise is pink noise, which is similar to white noise but drops off at 3dB per octave, which more accurately models the “curve” of human hearing, and we actually find quite pleasant. Music is often mixed to a pink noise slope, and other things like rain also have a frequency response similar to pink noise."
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bxz9xx | Why do some recent films from the 2000s need to go through a remaster process into higher resolutions like 4K? Aren't the original source files already at their native resolution, especially if they were filmed digitally? | Technology | explainlikeimfive | {
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"No, there was still a lot of film used in the 2000s. Even so, digitization for HD (1080) is very different from digitization for 4K (2160) because different bitrate limits are needed for the different formats. There might have been a 4K \"digital\" version for theaters with digital projectors in the 2000s, but that's not the right bitrate for an Ultra HD Bluray.",
"Even now, films are shot in 4K or 8K but cgi is done in 2k due to rendering time. A remaster may be just re-rendering the cgi in higher resolution/native for the film.",
"Most feature films were still shooting on film in the 2000s, and digital didn't make up the majority of productions until the 2010s. For anything originally shot on film, it makes sense now to go back and re-scan those elements at 4K (or higher) as most Home Video versions done in the 2000s and into the 2010s were only 1080p. Even if a 4K Digital Cinema version exists, there's still a color conversion process that needs to happen and requires creative oversight before that could be viewed at home in 4K. & #x200B; Even for films that were shot digitally in the last 15 years, there are some that are worth re-mastering in 4K. 10 years ago, it was a big deal to try to work with 4K files even if your camera was capable of recording them. Many projects had the cameras recording at 4K, but only went through finishing at 2K to save time and money. For those projects, it would be worth it to re-master them from the original camera files now that it's easier to work with those materials and we can actually watch material in 4K at home. & #x200B; In addition to those two cases, the advent of HDR and Atmos for Color and Sound are other new technologies that can be added into the finishing process for anything being re-mastered in 2019. Anything shot on film and a majority of material shot on digital cinema cameras has the necessary information to create an HDR version but it would take a remastering process that goes back to those original camera files or scans rather than just being able to do some kind of conversion.",
"A film like your describing will need to be “transferred” to 4k from master and then encoded into whatever format for distribution. The source files or “masters” are indeed at their native recorded and maximum resolution/quality. That is why the process is called remastering. They’re going back working off the master.",
"Nope! many were filmed in 1080 native. The Clones Wars was the first big digital movie and it was 1080. So they basically can never have a 4K version of those films. Because you can never make a resolution higher then source filmed.",
"I wonder what the new scanners can scan 35mm film to. What about imax film? Is 16k possible? imax scanned URL_0",
"Our first feature was shot in 2004 and a snakeoil salesman convinced us that we should use this all-digital Panasonic. It was used on Episode 1, he claimed (we later found out it was just a vfx shot b cam). We were fresh out of school and it was pretty cheap! Until we found out the deck was 20K to rent and we had to carry $1M in insurance because there were only two decks in the world. The footage was 520i at 60 fps giving us an effective 720p, but with tons of combing. The high def version we finally released used a Photoshop batch to decomb the source frame by frame and then we had to manually conform to 23.98. It was GRUELLING.",
"For most mainstream theatres outside of New York and Los Angeles, the first major digitally shot and exhibited film was Hannah Montana in 2005. And the last of the first run 35mm houses were gone by 2011. So that gives you a good frame of reference for the transition on the front end.",
"They're all shot at a higher resolution (especially anything that is film stock, since film can be projected to massive sizes before it becomes blurry, but need to be exported for the higher format. Rather than exporting at a higher resolution which means a lot more rendering with original assets, an easier way is to simply interpolate the pre-existing 1080 version."
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bxzv8a | Noise canceling headphones works by picking up sound and playing the reversing the sound wave. But how does this happen in real-time? | Technology | explainlikeimfive | {
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"Well in electrical terms all you have to do is flip the signal so positive values are negative and vice-versa. This can literally be done by wiring a mic the 'wrong' way round. Of course headsets do use a little chip for this to also apply some processing and improve the results. It's worth remembering that the speaker is typically a few CM closer to the ear than the mic, and since electricity moves much faster than sound (sound typically being around 343m/s in air, and electricity being nearly 1'000'000x faster) it's not really a problem to run the input from the mic through a chip and then to the speaker in time to cancel the originating sound.",
"Imagine you're on a boat in a body of water and large rolling waves are lifting and dropping the boat (something that might make some folks sea sick). To smooth out the water so you don't notice the waves, we generate more waves that exactly match the waves rolling under your boat BUT, we shift them forward 180 degrees to \"fill in\" all the valleys between the peaks. This way you feel a \"smoother\" ride. Best I can do without bringing in the science behind sound waves and the electrical theory behind microphones, speakers, and noise cancelling circuitry. Just remember, sound is slower than light by a long shot. We can take in that noise, cancel it, and replay it with very little lag time."
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by1n4o | How are rain chances calculated? | Technology | explainlikeimfive | {
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"text": [
"Its a historical comparison. The weather man says \"50% chance of rain\" he means \"half the time the conditions (temp, humidity, etc) are like this, it rains\"."
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by2xtv | Did old films really looked that bad back when filmed or it's just because it's deterioration over time? | Technology | explainlikeimfive | {
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"Depending on which version of an old film you saw, it could have even looked worse back then. A lot of the versions you see now have been remastered.",
"TL;DR - The quality of a film negative itself has gotten better over time in addition to our ability to view and reproduce the image on it. Full Explanation: A well preserved film print or negative will actually hold up really well over a number of decades. If an old film looks bad, it’s for a variety of reasons: If you’re watching a film print in a theater that had been screened hundreds of times, it’s going to collect a ton of dirt and scratches. Also the commercial prints that were made for theatrical distribution are a couple of generations removed from the original negative, so there’s a loss in quality compared to a modern hi-resolution scan directly from the negative. If you watched an old movie at home that was originally shot on film, the film-to-video process that was used way back when is terrible compared to today. It got better when things went digital, again when we went to HD, and has finally caught up to the resolution of film now that we’re dealing with 4K and beyond. For old TV shows that were broadcast live before the invention of video tape, the method of recording them was to point a film camera at a television and ‘film’ them off of a TV screen. (Kinda like using you 4K smartphone camera to record a video that’s being broadcast on your HDTV). Lastly, the detail in film stocks greatly improved over time and so did the resolving power of lenses. A modern film+lens combination in 2019 is capable of capturing a much more detailed image than what was possible in the 1940s, 50s, 60s, etc."
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by9da4 | when a 2.40:1 movie was cropped to 4:3 for old TV screens, you could see more in the top and bottom of a shot then when it was in 2.40:1. Why? | Technology | explainlikeimfive | {
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"You're describing films that were shot in \"matted\" style. The original standard aspect ratio of most films was about 4:3 (technically 1.37:1) until TV came along. TVs adopted Hollywood's 4:3 ratio, but to combat the competition Hollywood began producing films in widescreen. The trick is, the actual film itself, as in the hardware of the camera and film stock, was often *still* a 4:3 ratio. The director and cinematographer would have the widescreen ratio in mind -- perhaps with a superimposed rectangle on the camera viewer -- and just framed their shots with the top and bottom being ultimately useless. They would then distribute the film with mattes covering the unused top and bottom parts. When cutting the film for 4:3 television, editors had a choice (or perhaps they didn't and just went with whatever option they were given). They could use the finished, matted widescreen version and just pan from side to side depending on the focus of the scene (called \"pan and scan\"). Or they could get their hands on the original, un-matted print that was in a nice convenient 4:3 format (called \"full screen\" or \"full frame\"). The consequence of the \"full screen\" presentation is that a big chunk of that top and bottom part of the frame is not intended to be seen, so there are lots of occasions where boom mikes and other revealing mistakes are visible in full screen movies but hidden in the widescreen release. So for several decades, movies seen on TV usually had either a jarring pan-and-scan effect or had crew equipment occasionally popping in. VHS widescreen releases began to gain in popularity in the 90s and for a number of years DVDs were sold in either widescreen or fullscreen/pan-and-scan versions (or sometimes both on one disc) as 16:9 televisions began to take over. I worked at a video store throughout this transition period in the 2000s and can attest to the outcry from 4:3 TV owners who didn't want to see the \"black bars\" on widescreen movies (\"I paid full price for my TV!\")."
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by9yz6 | ACPI and UEFI. What are they and why do computers needs them? | Technology | explainlikeimfive | {
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"So, ACPI and UEFI are two separate things, so we'll handle them separately. * ACPI (*Advanced Configuration and Power Interface*) provides an open standard whereby the operating system and hardware components can talk to each other; ACPI advertises the hardware and its functions to the operating system, which can them provide power management to those devices * UEFI (*Unified Extensible Firmware Interface*) is a replacement for legacy BIOS (*Basic Input/Output System*) functionality that was ubiquitous in personal computers. Anything you could do in BIOS, you now do in UEFI. You might still hear people talking about the BIOS, simply because of tradition."
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bydwlk | Why is 5G exceptionally faster than 4G/3G ? | Technology | explainlikeimfive | {
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"It isn't. If you go to 5G and have much better speeds, then that's only because you were getting slower 4G than you could have been. 4G networks can, in ideal situations, deliver speeds up to about half a gigabit. You probably don't get anywhere near that! I know I don't. The main reason that 5G looks so much faster than 4G is that if you're somewhere with 5G availability, you're getting the very best technology that's on offer right now. Also, there's less saturation of 5G-specific frequencies right now. Also also, 5G does a better job of keeping signal from spilling over to places it's not supposed to be. That in turn means that most users of 5G will get more bandwidth - and more bandwidth almost always means more throughput (though they're not the same! Lots of people use the terms interchangeably, but bandwidth is measured in Hz and throughput is measured in bits/sec. Moving data around is complicated, so there's more to your speed than just how wide your channel is or how quickly the data gets to you)."
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byg17y | How does computer memory work? | When you physically save a file, like a photo or a word document, how is it physically saved? Where is that document physically? I believe there are two modern memory devices, HDD and SDD, but how do they work? How can a Hard Disk Drive be ‘scratched’ the right way to save my essays? And when I save a file to a flash drive, where on the flash drive are my documents? How can another computer read that flash drive? Is it a series of electrons or switches moved to remember each part of the document, like the 38th word on the 4th page? | Technology | explainlikeimfive | {
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"What you're talking about is called disk or storage. Memory is a different part of the computer, also called RAM. With a traditional disk drive (HDD \\ Hard Disk Drive) there is a spinning metal disk that is given magnetic charges that represent ones and zeros. Those ones and zeroes can then be read back as data. The charges are wrapped around the disk in a spiral, as if you took a credit card magstripe and layed it along a vinyl record. HDD's can increase storage space by having multiple spinning disks (platters). Modern SSD (Solid State Drive) storage use the same technology as a USB flash drive, Non-Volatile NAND flash memory. Simply explained, there are large numbers of tiny no-moving-part electronic switches made from transistors, each switch representing a one or a zero, and the switches being organized such that they can be represented as a linear series of ones and zeroes, just like an HDD. When you save a file onto a drive, the computer saves the ones and zeroes into a spot with enough room to fit the ones and zeroes, then adds that spot to a table of contents at the start of the drive. Another computer can read the files off of the drive by looking at the table of contents to find where different files begin and end."
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bygz7v | Why are RGB LEDs bad at producing purple (and nearby variants)? | Technology | explainlikeimfive | {
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"text": [
"Are they? RGB can represent millions of colours, purple too"
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byhvqq | How does Google Stadia or other gaming streaming services work? | Technology | explainlikeimfive | {
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"text": [
"The game, is run normally on a machine in one of Google's (or whoever's) data-center. Your computer sends it your inputs (so controller/mouse movements and button presses) which are fed into the game. The server then sends you the video stream of the game, just like youtube or netflix does. The big challenge is getting the response time (so the time between you pressing a button and the video of the game reacting to your input) low enough for the game to be playable."
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byi0mg | Helicopter Spinning Blades | Technology | explainlikeimfive | {
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"text": [
"They match the frames per second the camera captures at. So every 'photo' the camera takes is close to matching the speed of the rotor."
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byich5 | Why do Live-streams usually have such a high quality when Video Calls are often low resolution and stutter-y? | Aren’t they essentially the same technology? A video and audio feed being streamed to another location? | Technology | explainlikeimfive | {
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"At the most basic level, live streamers tend to have higher quality cameras, as well as higher bandwidth upload speeds. This means more, higher quality data can be sent.",
"Couple reasons.. 1. Live streams have a programmed delay. It's not really live, and on some streaming programs you can define this value so it adapts to your bandwidth. 2. This brings us to hardware. With a large bandwidth, stable and fast Internet connection you can send video and audio almost instantly without problems. This is usually achieved with a wired connection and optic fiber connection to the provider. 3. How do we understand real time? For us to think something is live, we need to see almost real time feedback to what we say, coordination video-audio, and no stutter/freezing. With all this together: live streams are made to feel live, while videocalls are actually what a live call would feel on average hardware, either with 0.3 sec between your question and the other person listening it, uncoordinated video feedback, or crappy video quality.",
"Software and expectations play a big role. People who make livestreams, expect them to be treated like a show, they want it to have very good quality, so the software works on making quality a top priority this can cause delays. Also, streamers will have high quality cameras, microphones, and video encoders. On the other hand, video calls are treated like a phone call, the most important thing is to have as little delay as possible, so the quality is set intentionally lower in order to make sure there are no problems receiving on the other end. And on the hardware side, unless you've got professional video conferencing equipment, you're probably talking about video calls on your phone, which don't really have the most amazing hardware compared to what pro streamers would have.",
"A very simple answer is that for a video call the computer needs to process that video information and compress it to a smaller format to send over the internet VERY QUICKLY since the call is in essentially real time. To allow for a wide range of devices to be able to do this, it compromised on quality because good quality compression takes either time or a lot of computer power. Streamers don't have this problem because live streams are delayed by a few seconds (and don't have to receive information, just send) and streamers usually have powerful hardware especially for streaming so they can output good quality video.",
"Hey there. Twitch streamer here. When I stream, I'm usually spending 20 mins before perfectly tweaking my lighting for the evening. That's a big key part of my camera quality. Even a $20 camera can look decent with the right lighting system. Most people on face time aren't sitting in the \"sweet spot\" with a 3 point lighting system. The other factor that covers the game window and all other aspects of the stream is the bitrate. Highest you can UPLOAD your stream on twitch before partner is 6Mbps ish. So the software compresses the raw image into one that can fit onto 6megabits (per second), which actually reduces the quality from the raw (my stream raw is closer to 40megabits than 6). Web calls are often around 1 megabit to account for the fact they may be on a cellular network, want a lower delay etc, so the compression (which reduces the quality) is way more aggressive."
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byifft | What determines the "computing power" of CPU cores? Why is an ARM core generally considered less "powerful" than an x86 core? | Technology | explainlikeimfive | {
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"This is a very complex question if I get in depth on the engineering decisions that make them different, but without that, it becomes oversimplified. Heat. Think of phones as ultra small computers. Unless you want a fan in your phone, they depend on passive cooling, and unless you want the phone to be heavy, batteries can't be very big. Now, luckily, if a chip takes less energy to work, battery needed to keep it running is smaller, and that energy which is dissipated as heat is less of a problem. With this in mind, the whole concept of a portable phone requires low power chips, and low power means lower performance, even if performance per watt (power and energy required) is better.",
"Okay, let me try. First of all, for simplicity, remove the idea of \"core\" from the equation. A core is just a processor. An 8 core CPU is 8 processors stacked together. This is done because we've bumped into the limit of how good we can make a single processor, so we've decided \"screw it, if we can't make one 8 times better, let's just use 8 of them\". With that of the way, what is a CPU clock frequency? It's a beat. Think of a guy banging on a drum to set a rhythm. That's all it is. When the drum goes \"bong!\" something happens. But that beat is just there to keep things running smoothly. Nothing dictates how much stuff much happen from one beat to the next, so you can't usefully compare a 2 GHz ARM CPU to a 2 GHz Intel one, or even Intel CPUs of different generations. Now, what makes one CPU better than another? Loads of internal design stuff. Let's say that the first CPU design we had couldn't multiply at all. So if you wanted to calculate \"2 * 500\", what you'd have to do is to \"add 2, 500 times\". This obviously takes at least 500 times as long as a single addition. So that's slow, inefficient. For the next CPU we figure out how to create a multiplication instruction, and it takes say, 4 times as long as adding (because multiplication is a more complex operation). So now \"2 + 2\" takes some amount of time, \"2 * 2\" takes 4 times as long, but \"2 * 500\" also takes 4 times as long. We're improving! And in the generation after that, we designed some really fancy circuitry to make multiplication happen exactly as fast as addition. Repeat this kind of thing, many times, and we've got the hell of an improvement."
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byih0c | What is preventing us from effectively storing energy harnessed by windmills and solar panels? | Here in Denmark, we frequently have to sell excess power gathered by especially windmills at very low prices to neighbouring countries, because we are not really able to store it anywhere. Is this a matter of the sheer amount of energy that has to be stored or are there other variables involved? | Technology | explainlikeimfive | {
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"You have to turn the energy in potential energy and then later release it to get electricity again. This is always a process that involves some losses. You can improve the efficiency a bit, but you will always have some loss. There are many ways you can store energy. A commonly used one is a flywheel. You use the energy to make a weight spin around and later use the spinning weight to generate electricity. This works somewhat in the sort term but the longer the wheel turns the more energy it loses to friction. There are also limits to how big you can make these things and they have to be by their nature stationary. A flywheel on a moving vehicle will encounter all sorts of problems. Batteries that store electricity as chemical energy are good for longer storage of energy, but they have a very limited capacity. They also involve all sorts of nasty chemicals to build. They are good for small mobile needs to store energy but less so for huge ones. You can have something called pumped storage, which is basically storing electricity by pumping water upwards into some storage and later releasing it though some regularly hydroelectric generators to get new energy. With this method you are only limited to how much water you can store. An artificial lake on some hill may hold much, much more energy than any battery of batteries ever could. You don't need to use all sorts of rare or nasty chemicals to build an artificial lake, but you do need to turn some place that is not currently a lake into one, which will affect the local wildlife a bit. So it is not 100% green. You also have some losses due to evaporation if you store the water for too long. The main issue however is that you need a suitable place to build it. Denmark for example is not know for it mountain ranges and hill country. There is no suitable place to build anything like that there. However some people have looked into alternatives that would involve pumping air into caverns to pressurize them and later using that air pressure to make electricity. Denmark apparently has some caves and caverns and old mines that might be airtight enough for that to work in theory. Currently it is cheaper to sell surplus energy and buy when there is a deficit rather than spend money in trying to create a storage that would lose most of the energy anyway.",
"Cost. The cheapest way to store energy is by using water; either heating, cooling, or raising it while excess energy is available and then using it later, but the first two option requires the construction of a *huge* thermally insulated tank while the third is just fairly inefficient in converting back into electricity (the first two don't even attempt this) as well as requiring a large container be constructed somewhere above the level of ground water. If you want to store electricity in less space, your best options include lithium batteries and hydrogen gas. Lithium batteries are expensive and supply has a hard time keeping up with the demands of consumer products, never mind national power grids, while hydrogen tends to leave whatever container you put it in and then catch on fire for any reason whatsoever, often explosively. Besides, selling our wind power cheaply has the fairly massive benefit of cutting down on the pollution created by our neighbouring countries. Not by a large amount, but every little bit helps, and the price we sell it for is still higher than what could be gained by storing and selling later."
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byj3um | Why do some games (e.g. Minecraft) need a launcher instead of directly launching the game ? | Technology | explainlikeimfive | {
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"There are at least a few reasons. The launchers that many games have now allow the game to check for updates when you open the launcher. It also allows for in game stores and advertising. There are probably many technical reasons as well, but this is why a lot of companies have launchers for games you would not think need them."
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bykcy7 | How can cell phones send signals such long distances? | Massive cell towers and powerful broadcasting equipment are required to get the signal to your phone, so why isn't it required to get the signal from your phone to the towers? | Technology | explainlikeimfive | {
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"The big cell towers are there to provide broad geographic coverage and handle thousands of calls at once. The size and power is not related to communicating with one phone but thousands. The receiving antennas in the cell towers are able to pick up your weak signal and hand it off to the rest of the switching system.",
"The tall towers help your phone get its signal through as much as they help the cell site. Cell tower transmitters have around 10 times as much power as a phone which is not considered \"powerful broadcasting equipment \". They also have 10 times better receivers than phones. The reliability of both directions is equally important and cellular systems are designed to have roughly equal performance in both directions."
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bykf3z | How does Alexa read so naturally from a book, with proper inflection, etc.? | I asked Alexa to read from a book in my kindle library, and I was surprised that "she" read so naturally. I was kind of expecting a more monotone, computer-sounding voice-- it's a pleasant female voice, of course, but I wasn't expecting so much natural expression, for example, rising at the end when the sentence was a question. I listen to audiobooks a lot, and those are read and recorded by professional actors, so they sound very natural because they *are*, in fact, being read by human beings. Alexa was almost that good. How is it that Alexa's reading skills sound to human? I don't know anything about AI, so maybe this is a dumb question that everyone knows the answer to. But hey, I'm 5, okay? | Technology | explainlikeimfive | {
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"I'm not an expert on AI either, but I believe that Alexa can train herself to get better. Same goes with Siri, Google, and other assistants. Millions of users talk to them every day, and by listening to the users, they can recognize speech patterns, and even accents. Eventually, they improve and gets better at producing natural speech. One thing to recognize is that this is machine learning, so the AI gets better gradually by processes close to trial and error. If you look at them, say 5-7 years ago, they were horrible and monotonic. As humans interact with the AIs more, they can use more data from the interaction to improve.",
"Basically, they record you and send it to a server, then an AI “studies” it and learns it. Also, this is the reason Siri sounds so terrible compared to Alexa or GA since Siri doesn’t record you so the AI has much less info to work with."
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bykq8m | How do noise canceling headphones... Cancel noise? Could they be "upgraded" to silence concerts? Gun shots? | Technology | explainlikeimfive | {
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"Okay so sound is a wave. Noise cancellation works by listening to the waves on the background and then outputting the opposite wave to cancel it out. Think of sound as waves in a tub, you can stop them if you do a \"counter wave\" movement right? That's literally noise cancellation",
"I used to work on audio for a big company. One of the things I used to do was noise cancellation. There are three types of noise cancellation: -passive: the headphone material will block most of the sound. -active 1 (I'm going to call it that way): relies a lot on passive cancelation, it uses a mic inside of the headphone to pick the sounds that make it through the headphone and there is a circuit that cancels that sound by playing the same sound but on inverse polarity. -active 2 (same situation): it is similar but it has an external mic and an internal mic. The internal mic is optional and it is used to pick the error signal. Once you cancel the noise there is some noise left regardless of how good the headphones are. The error mic if present, is used by a DSP to calculate if the cancelling is done correctly. The error mic is optional and most companies only use the external one in headsets but phone companies often use it on the hanset. most Android phones have a mic next to the speaker for this purpose.",
"Can they cancel concerts or gunshots? No, because sound can reach your cochlea via bone conduction. There are headphones which use that effect."
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bymtet | Why does 5GHZ seem to be the ceiling for conventional desktop overclocking? | I know that overclockers can push CPUs s further than that, but ~5GHZ seems to be the clockspeed today's CPUs max out on since 2011. Why is that? | Technology | explainlikeimfive | {
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"CPU speed is limited by time of transmission and heat. The electrical signal has to be transmitted through microscopic wires in a chip. Though the theoretical limit is the speed of light, the realistic limit is determined by the material that conducts the electrical charge. Additionally the gates -- the circuits -- have to switch from 0 to 1 -- open to closed -- and that can only happen so quickly. So there are physical, engineering limits on how fast those things can take place. It is possible to make those things happen faster -- that's basically what overclocking is -- but when you do that it generates additional heat. Without appropriate cooling, the heat will eventually burn out the microprocessor. Because of the size of microprocessors there's only so much cooling you can bring to the table, so as you try to speed up the chip you reach a point where the additional heat outstrips any attempts at cooling, and you burn the chip up. The combination of transmission speed and heat dissipation create the limits on CPUs.",
"URL_0 Theres a few reasons, cpus can definitely go kver 5 ghz, some have gotten up to 8 ghz, but you need a lot of cooling, much more than a standard PC (issue 1) The second major issue is on CPU design. CPUs are mad eof a bunch of really tiny transistors. For a CPU to operate faster, these transistors need to work faster. Weve reached a point where its difficult to develop faster and smaller transistors, so until we do thay cpu speeds wont increase much.",
"It all comes down to heat The heat created by a transistor goes up linearly with the frequency, and with the square of the voltage. When you switch a transistor in a CPU you're really charging up a capacitor from the gate to all the other points. To get a stable overclock you need to make sure that each gate is in the right state when its expected to be, and to get them to change faster you often need more voltage. The end result is that when you increase the frequency you also end up increasing the voltage and you can end up close to power going up with the cube of the frequency increase once you get high enough. If you can run at 1.05V at 4 GHz and 1.3V at 5 GHz, but need 1.5V to hit 6 GHz then you're going to have to deal with 3x the heat and it becomes really difficult to maintain a safe temperature when you have to remove such a large amount of heat from such a small surface area unless you use exotic cooling(aka liquid nitrogen)",
"We've hit the practical physical limits of the primary material substrates that we're using (silicon). Apparently, if we can ever get graphene working for chips, that's a material substrate that can stand significantly higher heat without deforming, and allow for much higher clock speeds. But we'll hit the material limits on that too, and the easy improvements too will come to a halt.",
"Basically it comes down to materials and heat. The materials we use and the side plays a big part. This is a big reason multicore came into the market, single cores were reaching the limits. Think of it as little switches being flipped. Each time you turn the light on and off it takes time. Eventually you hit the limit of how fast you can flip it with your finger and need to redesign the switch. Then it comes to heat. Each flip of the switch makes a little heat. If you cant get rid of the hear fast enough things begin to brake down. Edit: materials meaning gold, silicon etc...",
"So I've grown up in an age where CPU's went from a couple of MHz as a child, to my first PC being a 200Mhz Cyrix M2 CPU. Then we went to GHz speeds with the P3 (I used to have a dual socket 1.4ghz Tulatin machine for giggles) and into the P4 range with speeds of almost 4Ghz. It was at this point that they discovered that going faster was tricky, so we got Hyper threading, then multiple cores. The latest machines we are buying at work have Xeon Platinum CPU's with a maximum of 56 cores. And even then they now have issues with thermal dissipation! We can't buy FC430 blades with newer CPU's due to the TDP issues.",
"5 GHz = 5,000,000,000 Hz Speed of light = 299,792,458 m/s 299,792,458 m/s / 5,000,000,000 Hz = 0.06 m = 6 cm = 2.36 inches So, light (and electrons) can travel at most 2.36 inches during 1 clock cycle (though electrons go slower than this, depending on the material and factors such as temperature). It literally can’t get from one edge of the cpu to the other (the pathways inside of chips is not a straight line). There have been small increases by reducing the chip size, and you can do trickery where you store values inside the cpu for faster retrieval, or not wait for the last click cycle to fully finish before starting the next, but general consumers prefer reliable computers, so the limits aren’t pushed too hard."
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bynhgp | How does stretch tape stick to itself when pressure is applied to it, but not feel sticky to the touch? | Technology | explainlikeimfive | {
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"It’s kind of like Velcro but instead of hooks and loops that stick together, there are little folds/grooves that fit in together which will hold the sides of tape together.",
"It seems there are several types of tape referred to as stretch tape that are very different from each other. Which kind are you referring to?",
"Is stretch tape another name for self amalgamating tape?"
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byqe9y | What is the point of the machine (clapperboard) that starts a film? | Technology | explainlikeimfive | {
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"It’s used by movie editors/producers to synchronize the audio and video. In the old days, it would have the scene/take numbers on it, too. You could synchronize your video to your audio by listening to and looking at the clap.",
"The clapper is used to synchronize the audio and the video in a movie. Editors can pinpoint the exact frame where the clapper snaps closed and match the audio to it.",
"Before the days of digital, it was used to signify the part of a film they were shooting that day. Films are not usually filmed start to finish like how we watch it, they're filmed as the studio is available, sometimes an actors hair or beard change so they film longer hair/beard first...stuff like that. The numbers indicate where on the story board they are so the editors know where to insert that section into the finished product, and the sharp clap made by the board indicates where the audio should begin, as audio is generally always recording and you don't need the background noise before the call to action, so you can clearly see on a VU meter where the clap is to align/sync the audio with the video. Much of that is easier nowadays being the digital age, but the story board part is still true. They film the movie scenes in any order, and the editors still need to put all the scenes into the final sequence.",
"It's an easy way to synchronize sound and video when you're editing the movie - and the writing on it usually lists the scene number and take numbers, so that people could easily say \"Oh, scene 5 take 4 was great, we can throw out takes 1-3. Make sure to use take 4 in the final cut.\" The clapperboard is usually black and white striped because it makes it very easy to find the exact frame when the **clap** sound happens, because it would be the moment that all of the black and white angles lined up properly. You take the audio recording and synchronize it with the video starting at that moment, and you could be sure that all of the other dialogue and sound effects for the rest of the scene would match. Much easier than trying to read someone's lips and match the sound that way, for example."
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