I cannot seem to find a question I asked earlier

Question: I am new Ubuntu and Ask Ubuntu.
I asked a question today concerning how to make a desktop icon in GNOME, but do not know how I get back to the question, to see if anybody has offered a suggestion.
Comment: Your question is here: [https://askubuntu.com/questions/1143516/not-able-to-create-a-shortcut-on-the-desktop-for-url-from-chrome](https://askubuntu.com/questions/1143516/not-able-to-create-a-shortcut-on-the-desktop-for-url-from-chrome)
Comment: Since you're new to Ask Ubuntu, you'd really benefit by reading the help section: https://askubuntu.com/help/. There's guidance there on searching, asking, answers, etc.
Answer: You will most certainly know a few of the keywords from your question.
To find all questions I ever asked, containing the word python, I type in the search bar (showing "Search on Ask Ubuntu):
python user:me is:q

The result shows as a list:

To find all answers:
python user:me is:a

(q -> a)
Answer: Jacob's answer explains how to search among your posts, which is especially useful if you have many posts and a great tip for us all. However, I think in your particular case, you just don't know your way around the place yet and don't know where to find any of your posts in general. If you only have a few posts, or you want to look at the most recent post, the easiest way is to look in your profile.
Make sure you are on the main site, not meta. Click your username or picture or reputation score in the top bar:

And you will land on the Activity page of your profile:

Look or scroll down and you will see mini lists of your answers and questions with titles. You can organise these lists by newest, most recently active, or highest scoring. In my case, I have written more answers than questions, so answers appear above questions. In your case it will likely be the other way around.

You can click the Questions title to be taken to a more detailed list of your questions.
If the question you are looking for is not there, it may have been deleted. It is hard to find deleted questions, and you may need to ask a mod for help if you need to see your deleted question.
Note that you will receive a notification if anyone comments on or answers your question. The notification will appear as a red square with a number in it (corresponding to the number of messages) on the inbox icon to the right of your reputation and badges counts in the top bar. Unless you have turned off email notifications, you will sooner or later receive an email about such comments and answers too.
Answer: In the absence of any supplied information, the following assumes a
default Ubuntu Gnome 18.04 desktop. In the title bar at the top right
of the screen, left mouse click the section with your picture,
reputation, and awards. This brings up your profile.  At the top left,
select "Activity", and from the list in the middle of the "Activity"
screen, Select "Questions", third from the left.  Your Questions on
the starting (askubuntu) site will be listed.
Note that this answer, along with any other helpful answer or comment, is
totally useless in helping the user find their (first) question, since
some "helpful" administrator moved everything to another site (Meta,
since the question was arguably not about Ubuntu, but how to use the
site). Now the user's second question has disappeared!
Oh Meta-Meta where are you when we need you ;^O
Comment: Which icon(s) exactly? Where in the profile do you find the list of questions? How do you find e.g. the most recent or the most upvoted questions?


hybrid bike ... too small? risks?

Question: I bought a Schwinn from a big box.  I'm regretting it for technical reasons (shifters, brakes), but I'm starting to wonder if the frame is too small.  I have the seat way up and going down steep (paved) hills is a bit scary.  It feels a bit unstable.  It's a hybrid because my wife and I like to go on the C&O canal every now and then, but I am starting to put the miles on the road when riding alone (see the aforementioned hill... we have LOTS).  At 6'1", with a 33" inseam, should I have concerns about this 17.5" frame?
Comment: You might find a taller stem helps quite a bit. They're not expensive but check the sizing carefully. I assume the seat post isn't beyond its limits but you should check.
Comment: Frame sizes aren't standardized (even across same riding style and wheel size) -- one company's 17.5" might be another company's 19" in terms of fit. That being said, if it doesn't fit well, get something else. You can get longer seatposts and stems, but it might still not fit well versus something decent for you.
Comment: Sounds like a small frame, going by averages.  If you have short legs compared to your height it might be okay, but I have the opposite problem and need tall frames with less overall reach.   Try some other bikes - even just sitting on them in a (real) bike shop might show you more.
Answer: There is danger and there is discomfort...you should accommodate both.
There is a max insertion line on the seat post - do not ride the bike with the seat post extended beyond that line, buy a longer seatpost. Though I would imagine that a standard 17.5 frame would accommodate a 33 in inseam (is that your real inseam...or the length of trousers you prefer? There is a difference).
If the reach to the bars is too short, bringing your hands too close to the hips for your center of gravity, then you will feel that you don't have a lot of steering control.
It sounds like the bike is too small for your comfort - some people like small, whippy bikes and others like to ride much larger, more stable, bicycles. People are usually more comfortable on a larger bike, where they can change position during a longer ride and as the terrain changes.
Good luck, and have fun riding!
Comment: 33 is the trouser length.  Whippy is a good description for how this feels on a downhill.
Answer: First of all there are TONS of different types of hybrid bikes. You go from cross bikes all way down to coasters. Can you describe more what you have ?
It is that easy as look what size of frame you should use. All brands have chard of measures. If it is the right size well then you are fine. It should not be a problem having SLIGHTLY smaller or bigger that recommended size bike some brands have may be 8 different frame sizes for the same model some other cheap ones may have only 3 or even 2. This is where frames have huge differences between them and some BSO users may get the shiniest bike in the store with out knowing if it is of their size. So make sure that it isnt the case.
In hybrid bike (like mountain bike but with thinner wheels kind) geometry as far as I know the seat usually it is at same height or slightly over the stem so yes it is weird to have it far higher. Frames usually are quite big to the point where they looks bigger that same size mtb frames (they both looks quite similar). They idea is have a more comfortable ride that in a mountain bike and less rolling resistance or roads or gravel. So in theory you should not lay way forward.
I dont know/unsure if there any security risk of having a smaller frame maybe if you get your seat post to high it can break the frame because of leverage of your body and you will feel uncomfortable and may develop some joint problems over long period of time if you use it a lot.
Comment: It's a Schwinn GTX3.  I do feel a lot of pressure on my hands, so there probably is a seat/handle bar height imbalance.
Comment: it is possible that it is because of lack of practice ? did you tried to use gloves and/or ergonomic handle ?
Comment: I ended up selling my Schwinn and got myself a Trek DS3 with a 21" frame.  Fits perfectly and I no longer fear for my life.
Answer: Everyone's body proportions are different, and every brand's geometry is different too, but even with those taken into account, I'd say your frame is way too small.
Back when I was growing up, age 12 and 150 cm, I got a new mountain bike. It had a 20-inch frame. You're over 30 cm taller than age 12 version of me, yet your frame is smaller.
Today, I'm 180 cm (5 cm shorter than you) and ride a hybrid bicycle with a 58-cm frame. If your build is anything similar to mine, you should be looking at a 58 or 60 cm frame (22-23,5 inches; L or XL frame).
I can still ride the old mountain bike but it is a bit uncomfortable.

hybrid bike ... too small? risks?


How can I retrieve a deleted conversation in my text messages on Nokia Lumia 635?

Question: I had a whole important conversation in my text messages and I accidentally deleted it. I haven't backed-up my phone in two weeks, so I'm wondering if there's a chance to get back that conversation with the messages from that person? It's important. Thank you.
Comment: Drop a note to NSA.GOV and see if they'd send you a copy... ;-)
Comment: Did you have Messaging backup on? (Somewhat separate from "backing up your phone".) If not, then your carrier would be the one to check with.
Answer: Annoyingly, the only reliable way that anybody seems to know of to access phone backups is to activate your Microsoft Account on a phone for the first time. You can use a second phone for this, or just hard-reset your current phone. If you were backing up text messages - and haven't made a new backup since you deleted the important conversation - you should be able to restore the conversation that way.
Answer: Partial answer that I just discovered: it is possible, via Outlook.com, to view SMS messages you've backed up. Taken from this answer, which should have a lot more upvotes:

Go to https://outlook.com/. Log in with the Microsoft Account used on your phone.
Click the Gear icon in the upper right, next to your photo. Select Manage Categories (or Options, then Manage Categories on the next screen).
Check the boxes under "Show in folder pane" for Contacts and Photos. You can check the others too, if you want.
Go back to your inbox, and you'll see a list of "Categories" on the left-side panel.

Under Contacts, you will see your backed-up SMS, but so far as I can tell only the ones that you've received appear there (and only if you use "Arrange by Conversation").
Under Photos, you will see your backed up MMS (at least, the ones containing images), both sent and received.
Hope that's enough to help you out!


Can I swap BMX wheels for a larger size?

Question: I am a 5 foot 10 inches 14 year old boy who would like to get into riding a BMX. So if I was to buy a BMX with a certain size wheels, can you swap them for bigger wheels
Comment: 14 years old  ?  Remember you're still growing, so your bike will get relatively "smaller" over the next couple years.   Common thought is your height levels-off around 18 years of age, but stature tends to solidify for a few years after that.
Answer: If you are 5 foot 10 then you will be fine on a full size 20" wheel BMX. Each model size will be built for the specific wheel size, things like tire clearance and brake positioning will normally mean you can't increase the wheel size.
You might like to research how top tube length and bar rise affect the handling of a BMX for jumps and tricks. There is a question on BMX sizing here BMX Bike Sizing and Changing Parts? and probably lots more on the site to read through
Comment: What about if the frame is medium
Answer: One of the hardest things to change on a bike is the wheel diameter.  You can't go larger because the wheel will hit the frame, and you usually can't go smaller because the brakes won't work, or the pedals will hit the ground.
Tire width can be changed to a degree.  Going smaller is not too difficult (though a narrower rim might be needed at some point), but going larger is limited by frame clearance, and most BMX-class bikes are shipped with tires that are close to the widest the frame will handle.


Guitar hardware

Question: I could not find a possible solution to my problem. I recently upgraded my guitar with sperzel machineheads. The technician of the shop from where i bought my guitar did it for me. But he happened to put the tuners in an opposite way such that they are tightening the string anticlockwise. Should there be any problem for tunining? I feel some unbalance though listening to the guitar.
Comment: It shouldn't matter which direction you have to turn the tuners, except for getting used to it if it's the other direction than that you are accustomed to.  What does matter is that the strings are wound on in the way that they run as straight as possible over the nut.
Comment: 3 a side? 6 in a line? What guitar? Have the strings been wound on the opposite way? Have you taken it back to the guy? So many questions!
Comment: This does not sound like the machine heads are on backward, but rather that the strings are wound backwards. Did the tech at the guitar shop put the strings on? If so, take it back and make them fix it.
Comment: Machine heads on my Rikki 4001 turn the opposite way to every other guitar I own [inc. Strat straight 6 &  Yamaha, Fender & Line6 'double 3s'. Some just do;)
Comment: The strings are going straight over the nut and over wind over the tuners just like they do on any other guitar. It just that the tuners move the opposite way now.
Comment: Then no, there won't be any difference to the tuning: the string is still in the exact same place it would be, with the exact same tension
Comment: I'm going to drop some of this into a brief answer, just so there is one.
Answer: The only real answer, assuming your strings are wound correctly to give the straightest path through the nut is "Some are just made the other way round"
I own 5 guitars... two acoustics, two electrics & a bass.
One has 6-a-side machines heads [Strat], three are 3-a-side [Line6 & both acoustics] & one is 2-a-side [Rickenbacker 4001 bass]
All except the Rikki have the machine heads configured to turn in the same direction as each other for sharp/flat.
The Rikki goes the opposite way.
I can only assume it's a design difference.

Someone decided that "tighter" should be 'moving the top of the machine head away from the bridge' - also that's how the old peg system works, with no gearing mechanism. Most guitars would appear to be set this way.
Someone else decided that "tighter" should be clockwise, as it's a screw mechanism. This may be Rickenbacker-only, but I have no further evidence.

I can only assume that your machine head configuration is 6-a-side, Strat type, as that's the only one where 'anticlockwise = tighter' is consistent for all 6.
That would mean your new machine heads are 'standard' configuration rather than 'Rikki'.
Anticlockwise on the top side is 'tighter = top of machine head moves away from the bridge'
Answer: A machine is omnidirectional, tightening is a function of the direction that you wrap the strings with respect to the axis of the peg or post.
If you wrap the string clockwise, you turn the gear (or peg) one way to tighten. If you wrap the string anti-clockwise, then you need to turn the gear the other way to tighten.
The placement of the machines will dictate which way you want to wind them. On Strat, this means wrapping the string anti-clockwise. On a Les Paul, the top three wrap anti-clockwise, the bottom 3 wrap clockwise.
For Strat style heads, all 6 machines are identical, for heads laid out with 3 on each side of the head, they use two sets of 3 machines that are mirrored so that the shaft is "north" of the peg & gear for each side.
If you feel that they are backwards, reverse the winding direction. The "normal" way is to have the strings straight (as you can) from the nut to the peg, but aside from some minor mental adjustment it ought not be an issue.

Guitar hardware


Do I have to discard leftover sushi?

Question: We had a party Monday night and ordered Sushi for 20 people - about 25 percent of the Sushi went uneaten, mostly plain rolls like tuna and yellow tail.  I would hate to throw out 10+ rolls - any suggestions?
Comment: I was unaware that it was possible to have leftover sushi. Reminds me of a question I saw elsewhere once, on what to do with leftover champagne.
Comment: A friend of mine lived in rural Japan for some time.  He said that whenever a Japanese family would host a dinner party, they would often order a 200+ piece sushi platter and there would always be leftovers.  He said that the common practice was to leave the leftover sushi on the kitchen counter overnight---unrefrigerated---and eat it the next morning for breakfast.  I'm not recommending you do that, but at least that's what a portion of the Japanese do!
Comment: I realize this is quite an old post, but I think this needs to be stated based on the  posters suggesting to "use your nose": While it is true that fresh fish should have no "fishy" or "off" odors, your nose is NOT a food safety indicator.  Plenty of food, sushi included, can smell fine and be simultaneously incubating bacteria that can make you sick.  Smell is NOT a reliable indicator of food safety!  That is why we have to recommend the consideration of time and temperature.
Comment: I had the same problem last month... I was so sad while throwing away all that yummyness...
Answer: I'm assuming these rolls contain raw fish. If that's the case I'd urge you not to eat them raw the following day. It might be safest to just throw it out, but you could try deep frying them in a light tempura batter. Just a few minutes should be enough to cook the fish.
Comment: mmm this sounds delicious.
Answer: As hobodave points out, you'll need to cook the fish, because the leftovers won't be safe to eat raw.  While deep frying sounds tasty, I'd be concerned that the cooking time would be too short to kill much bacteria.  Perhaps you could layer them in a casserole dish, maybe throw some more rice, sesame seeds, sauce(s) on top, and bake until browned as an asian casserole of sorts.
Be smart, though, and if they've been out of the fridge for a long time, or if they smell strongly, just toss 'em.
Answer: First a red flag on the raw fish here. That said, some shops keep the sushi refrigerated for a couple of days before selling it. It's not what I prefer, but it is still edible. If you kept it out on a buffet for a couple of hours then I'd say you're going to have to say goodbye to the rolls.
If you're willing to take them apart you could go for a stir fry solution. Let's say a fishy variation on this recipe.
Before proceeding, consider carefully where the rolls have been and use your nose.
Answer: chop up your left over raw fish into tiny pieces and mix well with finely sliced green spring onion, tiny bit of soy sauce and sesame oil. Top your rice with it and enjoy!
Comment: This is dangerously bad advice. Are you familiar with basic safe food handling practices?
Comment: Using refrigerated leftover raw fish for the next day has never been an issue for me. You have to be sure of the quality of your fish when you buy it though.
Comment: So... no, then?

Do I have to discard leftover sushi?


Should I keep all my class definitions in the same class library?

Question: I am starting to work with class libraries in my C# class. We were told to write code that can be used more than one time. Should I keep all my class definitions in one class library for the length of the term, or separate them by project?
Comment: Class_Library != Single_File. Some people use it like that. You may have a Class_Library with several files, and each files, may have one or more related classes, interfaces, enumerations, etc.
Answer: Separate them by purpose. A class library is supposed to be cohesive. You shouldn't throw arbitrary things together.
For example, I just wrote an updater library. It has classes that deal with updating an application. But it doesn't have classes for some neat string operations because it doesn't make sense to add them. Any time I want to reuse some code, I want to reuse just one thing (for example this updater). If you throw everything together, it will be a mess and you will also force yourself to reference the whole thing when you really want to use just one. Give yourself the freedom to reuse the parts you want.
Writing truly reusable code is hard, but I definitely encourage you to try and do this. You will learn important things about writing actually reusable code.
I also suggest reading about YAGNI and KISS principles. Not to blindly follow, but to be aware of them.
Answer: Most enterprise code-bases I've seen organise their classes into different projects based on their purpose.
For example, within one solution, you might have the following projects:
SampleSolution.Presentation (User-interface things)
SampleSolution.BusinessLogic (Business rules/logic things)
SampleSolution.Persistance (Data-related things)
There are many variations on the particular name given to the library... For example, I've seen the BusinessLogic project named Domain, BusinessRules, Business... Just depends on your preference really. But the main thing is separating these items out makes things more maintainable and logical - it's a lot easier to quickly find the class you're looking for. Depending on the way the app is being developed, there might also be additional libraries such as Models, Views, Controllers, DTOs (Data transfer objects), and so on.
Depending on the nature of your assignment(s), it may or may not make sense to separate them up like this. For example, if you're going to be writing some classes which do things like manipulate strings, or perform calculations - those that fall under a "utility" kind of categorisation - it would make a lot of sense to put these all in the one class library. This way, in future assignments, you can just reference the compiled DLL, which is how you would typically use third-party libraries.
Answer: I use actual Class Libraries (i.e. DLLs) by purpose/architecture, and then further separate those using folders and namespaces.  For example in a typical app I might have:
Wayne.MyApplication.Domain (Business objects)
Wayne.MyApplication.Core (Common things required by everything else)
Wayne.MyApplication.UI (Interface)
and then further split them up (e.g. my Domain project contains folders for Models, Repositories, and Services).  One thing to be wary of is the "DDD Anti-pattern" whereby you have a separate project for your Domain objects, DTOs, Repositories, Services, Specifications, etc. etc. etc. when those are logical separations, not physical ones.


How to make top level menu think it has a current item

Question: This question has always tripped me up, but it seems like there should be an easy solution.
I have created a couple pages in a hierarchy as follows.
About Us
    - History
    - Mission

Events
    - Field Day
    - Labor Day Picnic

I have also created three menus in Wordpress.  A "Main" Menu that holds:
About Us
Events

This menu is displayed horizontally across the top of the website.  I also have two secondary menus, "AboutUsMenu" which just holds the following two pages:
History
Mission

The third menu, "EventsMenu" which holds the other two sub pages:
Field Day
Labor Day Picnic

I added a meta box on the page editor which let's me associate one of the two sub menus with every page.  This allows me to show my "Main" menu across the top of the website, and then on each page, I can dynamically figure out which sub menu to show on any page.
The problem occurs when the user visits a sub page, say /about-us/mission.  Since I'm on the mission page, "Main" menu does not give the About Us page a css class of current_page_item.  Technically, it's not the current page, but I would like to be able to style it as the current page since it is the active section as far the user is concerned.  Main menu doesn't know anything about the sub page so Wordpress can't add the current_page_item or current_page_ancestor CSS class.
I'm using wp_nav_menu to write all menus.
Can anyone tell me an easy way to link all of this together so the menus will understand they are the current menu items.
Answer: Would jQuery .parent() be an option for you?
jQuery('.current_page_item').parent().addClass("classname");

If not you could write your own iteration code for the nav menus and check the various conditions as you assemble the list, but I'm guessing this would be a lot easier.


Creating Iphone API for Aweber?

Question: I have to create a iphone app using Aweber. But Aweber has no iphone API link. Now I just want to know that I have knowledge of PHP and aweber has PHP API, is it possible to create a iphone API for a newbie like me  (I mean for Iphone) to accomplish this task.
Answer: You don't need a special iPhone API, you would use Objective-C to consume the Aweber API the same as you would use PHP, Ruby, Java, Python or any other language to consume the API for a web app.
The Aweber API is REST based so you can look at http://restkit.org/. From their website "RestKit is an Objective-C framework for iOS that aims to make interacting with RESTful web services simple".
If Objective-C isn't your thing, their is Titanium from Appcelerator, you use JavaScript to build your app and it gets compiled into Objective-C. Mobile Tuts has a nice tutorial on how to consume the Twitter API, which is also REST based. It should give you a good foundation to get you started.
(http://mobile.tutsplus.com/tutorials/appcelerator/appcelerator-using-json-to-build-a-twitter-client/)
Comment: require_once('aweber_api/aweber_api.php'); how can i do this  in c# or c objective
Answer: I am not signing up for an account so I don't know exactly how the API works, but if I were setting up an iPhone App to work with this, I would use the rails plugin.  Rails gives you JSON communication for free (IE no extra work required) http://guides.rubyonrails.org/layouts_and_rendering.html see section 2.2.9. Then use on IOS app use something like: http://code.google.com/p/json-framework/  to interact with that.
Answer: the iPhone does not have a fixed API reader, you can write your own,
http://www.aweber.com/faq/questions/200/Does+AWeber+Have+an+API%3F
The system has an API so there is no work that needs to be done for the system, just your app an API is an Application Programming(or some times known as plugin) Interface,
by reading that page it tells me they have an XML for which iOS libs have a parser built all ready so you can use that,
if your building the app, i would recommend looking at phone gap then your using JavaScript to control the API so alot simpler to work with,
And just a correction on your question they will not have a php API what they will have is a php library for talking to there API server,
https://labs.aweber.com/docs/reference/1.0 this link will provide you with the all the API calls you need to work with it's using JSON so php uses json_decode function to get the data from there servers,
Javascript within PhoneGap can call it without a problem from the phone.

Creating Iphone API for Aweber?


How do I write a "take action" scene for a play?

Question: Here is what I mean.
My character- Violet- started the play with a lofty attitude, but now her pride has been broken by her mother's death and betrayal of a friend. The scene begins with her reuniting with her brother- and she needs to tell him what has happened. I want the brother to become angry at their mother's killer. And I want Violet to come across more polite and empathetic. But how do I do that? At the end of the scene, both characters should be determined to fight the one who killed their mother.
Comment: Welcome to Writing.SE Ariel.  We're glad you found us and we hope you'll ask and answer many questions about playwriting and other writing topics.  Please check out our [tour] and [help] to learn more about how we work.
Comment: Your question here is pretty broad, as it's about several elements of the scene.  SE culture is to ask just one question at a time.  Your core question is about the siblings moving from inaction to action in regards to their mother's killer, but it's still not very clear exactly what you're asking for help with.  And there are a lot of side issues that may be questions too.  Can you try to get to the center of this?  Why wouldn't someone want their family member's murderer to pay for what they did?  (how, is another matter)  What is it you're having trouble achieving?
Comment: To my mind, the best "It's time to take action" moment from any scripted media has got to be the sequence to the Malcom in the Middle episode where the family go to Hal's Father's Birthday and Hal's sisters break Lois' to the point that she is in tears (No easy feat, I assure you).  I don't recall the name, but from the point that Hal and the boys realize what's happened to the very end of the episode is awesome and well done.  Without giving too much away, it can be easily found by googling "Malcolm in the Middle Family Reunion."
Answer: Embrace the conflict. Just like a screenplay, a scene can have an ACT I, ACT II, ACT III.
And people get absorbed in conflict, there should be some conflict in every scene, and your scene is built for conflict.
The Acts within a scene are obviously much shortened, perhaps to a single scene, but they still exist. For yours (call the brother Bob):
Scene ACT I, first half (12.5% of scene) Bob's "normal world". A scene of her brother doing something normal when she arrives; mowing the lawn, practicing fly fishing, whatever. Something that tells us WHAT KIND OF GUY BOB IS. Since he gets angry, you might want to foreshadow this in the scene: He's teaching his kid to fight, and they seem to be having fun at it. Or he is watching a martial arts contest, or shooting competition.
Scene Act I, midpoint: The inciting incident: Violet arrives.
Scene Act I, second half: Inciting incident escalates; Violet is crying; Bob sees it, asks what is wrong. "Mom was murdered. She's dead." This escalates, Bob can't believe it. Asks questions. Scene Act I ends with "Bob leaving his normal world," he cannot continue his routine, he is focused on his mother's murder.
We are 25% of the way through the scene. On to:
Scene Act II, first half: Bob's reactive phase. Bob expresses grief through livid anger. He wants to bring the killer to justice, punishment, death, what have you. He's a fighter, he wants vengeance. Torture even. Violet provides the resistance; reasons why Bob's impulsive reactions won't work, or will get him killed.
We have reached the halfway point in the scene (50%):
Scene Act II, second half: Bob's proactive phase. He still wants to bring the killer to justice; but having been thwarted (sensibly) by Violet, his brain starts working again. More planning on how to bring the killer to justice. Still a few objections by Violet (setbacks for Bob), but he is adapting to the problem. At the end of this Act, they discover the idea or clue to what they need to do.
We have reached the 75% point in the scene, and ACT III (climax and resolution):
Scene Act III, first half, climax (15% of total scene): Bob and Alice use the clue from Act II to develop their plan of what to do next, one they agree upon.
Scene Act III, second half, emotional resolution (10% of total scene): They know what to do, Bob's initial anger reaction has subsided with the climax; I'd reassert his grief at the loss of his mother, as the pair set off on their new mission.
Even if your whole scene is just two pages long, stick to the three act structure within that limit. Bob has a character arc to go through here. Basically all of this scene is part of an ACT I: We watch Bob go from his normal world to leaving it on a mission. If the scene is pretty short, you have to convey this stuff visually and with just a few lines of dialogue.
For example, in a two page scene, 1/8 of it is a quarter of a page. Not a lot of wiggle room!
But anger and grief are easy to show visually (music will aid it); Bob can throw or slam something, his expression can convey grief and rage. Violet's reaction to this can likewise convey her restraint and determination to get him over this phase.
You have to trust your actors; you give them the clues to what the character is feeling; don't be too specific in describing expressions; instead pick your words describing the emotion precisely and don't be too vague ("angry" is fairly vague; there are many types of anger; from cold to hot, quiet to loud, calm to violent). Actors will find the expressions to convey the precise words.


Why not use a cotton base layer?

Question: I am a little confused by this answer about whether or not cotton "kills".  Cotton is clearly a poor choice for an insulating layer in wet environments since its insulating properties are heavily dependent on its moisture content. The point of a base layer, however, is not to provide insulation but rather to wick the moisture away from your body. What people seem to leave out is that the moisture potentially ends up in your insulating layer (depending on the dew point and other factors) and I think takes energy to evaporate this moisture. This then leads to the argument of replacing the base layer with a vapor barrier. As I generally have no desire to hike in a plastic bag, would a cotton "base layer" serve as a reasonable middle ground between a wicking base layer and a vapor barrier?
Comment: Cotton doesn't really wick. It absorbs and retains. Once a cotton base layer gets damp from perspiration, it will hold the moisture and remain damp instead of wicking and allowing the moisture to evaporate. That's why it's such a bad choice.
Comment: It's a moisture barrier only in the sense that it holds moisture against your skin. I can't think of any environments, hot or cold, where that's desirable.
Comment: @CareyGregory but holding the moisture and not allowing it to evaporate makes it something like a vapor barrier, which some people consider a good thing.
Comment: Is not one solution fits all people and activities, I have a buddy that loves the vapor barrier system, I tried his setup and hate it, to me it feels like Im  wearing one of those plastic suits in 1990s weightloss ads and Im soaked and uncomfortable in no time. With my system he says he is freezing. All the theories aside I think that at first some trial and error is necessary to get to something that works for you and for the activity you are doing and noone says it has to be what others find comfortable, it has to fit your needs not theirs.
Comment: I'm voting this down for the moment because, based on the discussion in the answers and comments, the question is (IMO) not really "why not use cotton as a base layer" and instead some sort of more nuanced discussion on how to structure layers in general.
Comment: Related: [Does cotton really kill?](http://outdoors.stackexchange.com/questions/7571/does-cotton-really-kill)
Answer: There is a difference between just soaking up water and "wicking".  Cotton is hydrophilic, which means it likes to attract and hang on to water molecules.  Unlike a good wicking fabric (which relies on capillary action), cotton will not transfer that water up through your layers to the air as quickly.
Here are some reasons why a wet base layer is bad:

Cold - If you are wearing layers at all, you're probably not in "benign" conditions.  I typically don't wear more than one layer if it's not cold.  If it is cold, then you don't want water directly on your skin.  It transfers heat very rapidly.
Chaffing - Wet cotton chaffes.  I don't typically want my base layer chaffing me.
Microbes - Bacteria, fungi... microbes tend to like wet conditions.  Spending long periods of time wet in the wilderness is a good way to get a skin infection/condition.

The moisture ending up in your insulating layer is not necessarily a bad thing.  That layer is not touching your skin, and you have an air buffer between it and your skin.  That is definitely better than keeping that water against your body and since perspiration is not optional.
Regarding the risk of moisture ruining down insulation:  If you're in a region where the humidity is such that your sweat will not readily evaporate through your down layer... then you  probably shouldn't be using down.  Down is a less ideal choice for humid/wet environments.  But that's not a base layer problem and has nothing to do with why using cotton as a baselayer is generally a bad idea.
Another point about the insulation layer getting wet.  If you are sweating so much that you're soaking your insulation layer faster than it can evaporate then you're not managing the layers properly.  One of the key points of layering is to manage temperature and avoid sweating.
Answer: Cotton doesn't wick away any moisture, it will soak and capture it.  Furthermore cotton is heavy (compared to other materials), doesn't insulate, becomes wet very quickly, and stays wet for a long time.
Comment: @StrongBad -- Water on your skin is MUCH worse than water in your insulative layer.  Water conducts heat very readily.
Comment: Down is nice when you are sure it will stay dry.  It becomes waterlogged and useless easily.  Use Down only when it will stay dry.
Comment: @StrongBad -- There's something besides a cotton base layer that is going on here.  I've never soaked my down layer from perspiration... it evaporates out fast enough not to be a problem.  Grab me in chat and maybe we could talk over your system as a whole.  I suspect you have a problem somewhere other than your baselayer.
Comment: The fact that it holds the moisture is why I am considering it. I think cotton will cut down on evaporative cooling and keep my insulation layers drier. As for weight, I do not know what you mean. Cotton has a suboptimal weight to warmth ratio, but I dont use my base layer for warmth.
Comment: @RussellSteen If water gets into my down insulation , I am screwed. If heat gets into my down insulation, well that is less of an issue.
Answer: If you carry the right layers and adjust them well, you can often get away with cotton with no discomfort let alone danger in benign conditions.
But we shouldn't plan for only benign conditions and nothing going wrong. An example: If you're delayed and the weather changes for the worse, you could end up with cotton under waterproof layers just as the temperature drops. You're likely to get cold. If the delay means you're static outside you could get very cold. So what should have been an uncomfortable few hours caused by a fairly minor injury or a trail blockage gets dangerous.
You generally have to draw a line between a hike and a casual stroll where you would be very rare to have any difficulty in jeans, trainers and a cotton t-shirt + fleece/waterproof.  This line isn't always obvious.
I understand your desire not to wear a plastic bag - I used to share some of your scepticism about synthetic base layers. But only the very worst feel like plastic against your skin - and arguably those aren't fit for use as they feel like that because they don't wick. There's always merino, but my base layers need too much washing for it to be a good option so I haven't tried it.
Comment: Don't underestimate the insulation value of your base layer. But there are some dreadful synthetic base layers out there.
Comment: @StrongBad The point of the layer system is to spread the insulation through several garments. If your "insulating layer" is monolithic then you're not really layering, you're just wearing a jacket. If you really want to layer then the base layer should be providing some insulation in addition to other functions like wicking away the moisture from your skin.
Comment: I am not saying a wicking synthetic base layer feels like a plastic bag, I said a c appreciate barrier is a plastic bag. As for keeping warm, that is the job of an insulating layer.
Answer: Another disadvantage of cotton is that, because it holds on to moisture and gets saturated quickly it can get very uncomfortable where it is between your skin and your pack, especially around the straps and back. Over a long day this can get quite unpleasant and over a few days you can get serious skin problems from salty sweat being rubbed against your skin.
Answer: You must consider here why you would be sweating in the first place. So, you must take into account that the body may produce a bit more heat from time to time and it will want to dump that excess heat into the environment using evaporative cooling. E.g.in Northern Norway I had to travel a bit to get to a place where I could take pictures, when I arrived I was a little sweaty. I opened by jacked pulled my sweater up a bit for a few seconds and closed everything, the ice cold air was then trapped inside my clothing, as this heats up it becomes bone dry. The evaporation plus the ice cold air provided me with the cooling I could still use at that moment.
Had I worn cotton clothing instead of the wool + polyamide stuff, then what would have happened is that during the time I was feeling a bit too warm, I would have produced more sweat because the cotton fabric will hold on to fair fraction of the sweat. So, the evaporative cooling would have been less with the same amount of sweat produced per until time, therefore I would have produced more sweat. All that extra sweat would have ended up in the cotton fabric.
But when I reached my destination, I needed less cooling. I would still be a little warm, but all that saved water in the cotton fabric would keep on evaporating for quite a long time. If during the walk 50% of the sweat was captured, then this means that the same amount of sweat that I lost via evaporation during the walk, would still have to be lost. This means that the energy dumped in the environment during my walk will be radiated away again, but now I'm standing still and I'm producing far less heat.
Answer: The point of a vapor barrier is that it doesn't allow any moisture to escape.  A middle ground role would mean that it's not good at doing either job: cotton would soak through, and the moisture would spread to the rest of your layers.

Why not use a cotton base layer?


Spectral properties of CFT

Question: What are the general spectral properties of CFT? I mean what is the "spectrum"/eigenvalues of CFT in 2d and d>2 spacetime dimensions? I understand the "spectrum" and "Fock space" realization of Dirac equations, Klein-Gordon equations or even the Maxwell equations...But, how do we work with conformal invariance, either in 2d, where the conformal group is infinite-dimensional or in d>2 where the conformal group is "finite-dimensional"? Note: I think It is related to correlators of conformal fields but I need a more precise and intuitive(if possible) physical/mathematical idea of how we face CFT.
Answer: If you add the hypothesis of unitarity you have that the conformal weights of your field $\Delta_i$ must obey the following inequality:
$$\Delta_i \geq \frac{d-2}{2} + l$$
where $l$ is the spin of the operator.
The conformal bootstrap equation give you also constraints on the coefficients $C_{ijk}$ appearing in the 3-point correlation function.
As far as I know, a CFT is defined by a set $\{\Delta_i,C_{ijk}\}$ and these are the constraints on them.

Spectral properties of CFT


What should be the "depth of design"?

Question: We all know that the process of creating a design and the whole architecture of the software is very important before writing the code. But how deep should be dive into the design stuff - should we start from the general architecture and go down til the names of the classes or should be just designate common parts and start coding?
Comment: nice question. I've experienced that too much time spent thinking about design can slow you down. My advice is: Sketch out your general architecture and dive in. Then refactor to improve the code. However that's highly personal.
Answer: First, the following assertion you made isn't true.

We all know the process of creating a design and the whole
  architecture of the software is very important before writing the
  code.

Many, and arguably most development shops have come to the realization that doing a lot of design work up front is not beneficial. The problem is that at the start of the project, everyone (stakeholders, developers, etc.) know the LEAST they are ever going to know about what needs to be built (See Cone of Uncertainty). That is not the time to be making major decisions that are written in stone.
My advice is to do the least amount of design you can get away with before you start coding. After you have done a few rounds of prototypes, flesh out the designs with more detail.
Disclaimer: This advice mostly applies to development efforts where the problem is not that well defined up front and still feels very fuzzy. If you know exactly what you need to build and there isn't a lot of uncertainty, bu all means go deeper on your designs. That said, remember above all that your deliverable is working code, not a design document. Do only as much as you need to get the job done.
Comment: The Cone of Uncertainty applies to estimates. Even if you know exactly what you are going to build, it still holds (although is narrower) because you don't necessarily know how you are going to build it (a single problem has a near infinite number of designs with varying complexity) and what resources you have to build it (staffing, computational resources, and available funds all affect project duration/cost). Using the Cone of Uncertainty to decide how much to design is flawed, since the act of building architectural and design models and prototypes is what narrows the cone.
Comment: Good point Thomas. Even if you know exactly what you are building, it isn't uncommon for business requirements to change during a long development process. Don't invest too much up front on something that is likely to be outdated quickly.
Answer: This is driven by the development life cycle as well as the various project-level and product-level attributes. There's no single right answer that applies to all projects. Some projects tend to create a system architecture up front, and then enter into detailed design for portions of the system, either iteratively or concurrently. Other projects simply progress from architecture and continually refine the design, which is completed and baselined prior to starting implementation. Other projects might not need a formal design or architecture, and decisions and the current state of the project are captured informally.
There are a number of factors that can help you choose a development methodology, ranging from the amount of risk faced by the project, the amount of visibility desired by both management and the customer, the team's familiarity with the domain and technology, the volatility of the requirements, and so on. Steve McConnell's Rapid Development: Taming Wild Software Schedules has an entire chapter on choosing the appropriate methodology.
Answer:
We all know that the process of creating a design and the whole architecture of the software is very important before writing the code.

This is a false dichotomy.
Code is just detailed design.  Nothing more.
The hoped-for distinction between "design design" and "code design" is the presence of executable code.
However, this distinction becomes murky when we have UML-to-code generators.  If we create detailed UML, it becomes the code.
If we have a high-level, formal design language -- some kind of DSL that translates high level design or architecture into code -- then that DSL becomes the real code.
For example.  C++ used to be translated to C which was translated to an architecture-neutral intermediate form from which "code" was finally generated.  That means the C++ could be called a high-level design language.  It sure isn't very close to code.
If we use a high-level GUI generator and IDE to drag and drop icons which create code, what is that?  Is it design?  But it creates code, doesn't it?
I think the distinction between "design" and "code" isn't terribly helpful.
Which leads to the answer to your question.

should we start from the general architecture and go down til the names of the classes or should be just designate common parts and start coding?

It depends on what your audience needs.  You write design at one level so that they can take the design to the next level of detail.
Do they need classes?
Or do they only need design patterns into which the fill in the classes?
Or do they need method names?
It depends on your audience.
Answer: I'll point you to the Chapter 9 of the book Python Programming: An Introduction to Computer Science
by John M. Zelle, Ph.D. were he introduce the top-down design bottom-up implementation strategy and says that the analysis process eventually bring problems small enough to be trivial to solve.
I would say you should apply the same strategy and go deep were is trivial to solve the problem. But, when is trivial? it depends on your capabilities.
Answer: In my experience there are two parts to this question.

How detailed should the architecture be?
When should a certain level of detail be specified?

Answer to the first part, how detailed should the architecture be...
The architecture should have the least amount of detail that still ensures desired properties are appropriately promoted or inhibited by the system design.  Lower level details can be deferred to downstream designers (might be folks writing code, or perhaps another architect user of the system).  Remember that as an architect, your main focus is on system properties, the key quality attributes.  Depending on the property, you may need to design parts of the system to different levels of detail.
As an example, depending on the size of the system and the properties that you care about, for an architect overseeing a project with many teams, worrying about class names is too low level.  On the other hand, class names might be considered high-level design for a team lead responsible for implementing only a piece of the system.  (Aside: for small teams that do it all, you'll trade these hats daily.)
Answer to the second part, when should a level of detail be specified is a little more tricky...
One man's architecture is another man's detailed design - it all depends on your perspective of the system and the properties you are responsible for overseeing.  The only aspect of design that really needs to happen first is defining the boundaries between elements and layers of abstraction.  Once these are clearly defined, different elements can be designed at different levels of detail, generally (there are exceptions) concurrently.
When a level of detail must be specified could depend on a myriad of factors including...

Cost
Priority or value to the customer
availability (as are the people available to create it)
risk and uncertainty
technical dependencies
schedule
experience
and a lot more...
Answer: I think most companies these days are adopting Agile software development: http://en.wikipedia.org/wiki/Agile_software_development
The basic idea is that you:

only plan as much as you can accomplish in a short time period, such
as two weeks
do the bare minimum development necessary to meet the requirements of a specific feature (vertical slice) of the system.

Then at then end of your two week iteration, you consider your accomplishments and plan your next iteration. Some of the benefits of this methodology are:

you dont waste time planning for things you wont need
you avoid developing features that needlessly constrain future requirements
you get quicker feedback about how well your system is meeting the (often changing) requirements of the user
Answer: I would like to echo S.Lott's sentiment of "code is design" and JohnFx's advice of "design as little as possible before you start coding", but expound on why. The reason is simple - writing code is a process of discovery.
You can build castles in the air all you want, but there are things you'll only discover once you actually write the code. You'll bump into code duplication that you were simply never going to see when you were making a bunch of UML diagrams because the implementation just isn't there. You might realize a component needs to be broken up into two or more parts when you try to write unit tests for it. Moreover, you're chasing a moving target - even if you had the clairvoyance to think up the perfect design up front, it'll no longer be perfect once the requirements change.
The best advice I can give you is to follow the core idea behind agile methodologies: take a small step towards your goal, take a good look at the result, and use your newly-found insight to fix mistakes and correct your course. Keep doing that until you're done. And don't forget to Keep It Simple, Stupid!

What should be the "depth of design"?


Best way to estimate velocity of motor with encoder

Question: I'm designing a PMSM controller with the motor has an optical encoder, so I can get position information from the motor. But how to measure the velocity of the motor. Now, my design is to calculate the difference, then add a low pass filter to estimate velocity. The approach is not a good way when the motor runs at a low speed. I have read some research to improve velocity estimation, like Luenberger Observer, Extended State Observer, or Kalman filter. But I don't know what should I choose since I have almost no theoretical basis.
Answer: You could employ all the techniques you mentioned that are model-based though, meaning you need to provide a good model of your system and then tune the parameters.
Alternatively, there are other methodologies needing less tuning. Among all these, one of the best technique to use in this situation is definitely the Savitzky-Golay filtering, which performs least-squares fitting over a given time window.
In a nutshell, you have to fit in the least-squares sense the position samples contained within a temporal moving window using a line. The coefficient of this line represents the velocity.
Also, to improve robustness, you may want to make the window adaptive, as done for example in this work, one possible code implementation of which is available here.
Comment: I see Savitzky-Golay filter. But the filter requires the information of y(n+1), y(n+2)... These are future information of the system. And the example, 5 points window with 3 order polynomial, get Y3 = (-3 * y1 + 12 * y2 + 17 * y3 + 12 * y4 - 3 * y5). It seems no difference to FIR filter but looks ahead 2 points.
Comment: Nope, the filter makes use of past samples: it is a causal filter.
Further, it turns to be very different from a FIR since it performs least-squares fitting rather than a linear combination of the past samples.
Answer: In slow velocity error will be more since you are PWM mode. Try to use one Schmidt trigger circuit followed by a counter t measure speed. No need to use even filter.


Android Tablets: Use USB to Ethernet connector?

Question: Do Android tablets generally support USB to Ethernet adapters? And if so, which models?
Comment: [How to make Ethernet work on Android over OTG?](https://android.stackexchange.com/a/225741/218526)
Answer: Looks like 'no', with some xda-developers work.  If you want to connect to a LAN, why not go with an access point the size of a deck of cards?  If you want extra security, you might turn off your wifi router's beacon, use WPA2 without WPS, and turn on its MAC address filtering.  Your device will connect without the beacon if you 'Add Network'.
Comment: Is this still the case?
Comment: @Alex, if it's changed, the feature you're looking for from the new devices is "USB host".
Answer: To my knowledge, the Motorola Xoom does support the USB to Ethernet adapter solution, but I don't know of any others. Even the Xoom however requires some serious work, and you will need one of two custom kernels for the Xoom as well as an adapter based on a particular chipset. For more information, check out this XDA article and the threads it links to.
Answer: I'm using a Toshiba Thrive (OS 4.0.3), a Curtis KLU MID704 (OS 4.1.1, and one of the Rockchip clones) a Polaroid branded PMID704 and a ZTE phone. Of all these, the Polaroid and Curtis have Ethernet support in the settings. I'm using a Radio Shack Belkin USB-to-Ethernet adapter, which is supported off-the-shelf by Android. (Only the Toshiba Thrive has a full size type-A USB jack.) The Polaroid is "broken" in that the Ethernet doesn't work. You click on it in settings and it clicks but does nothing. The Curtis works, it shows me my IP and MAC address in settings and I can set static IP parameters including IP Address, Gateway, NetMask, and 2 DNS servers.
However, the Android frameworks (in the Java(tm)-like language) are broken. The connection managers only support WiFi and Mobile Data. You can inquire about the Eth0 device but can't open a connection or do anything with it.
I know...I've got a $70,000USD contract hinging on solving the ethernet connection problem and it's getting frustrating. I've got google people telling me it's in there, but I can't find API's or examples. Supposedly Google's working on it.
Answer: The most easy way to use LAN to your Android device is to connect your LAN cable to a portable wireless router ( about US$20 in ebay ) then you can use WiFi service from your LAN cable.
Comment: Not really answering the question here, you could do with expanding it a bit if you think you are.


JIRA query to find all issues where acceptance criteria is less than 20 characters

Question: can anyone help me with a JQL to filter all jira issues in my project that have acceptance criteria less than 20 characters
Comment: I think your agile is really broken if you need to do something like this.
Comment: This isn't really the right sub for this, it seems more of a technical issues with JIRA and contacting their support or other technology avenues would be more beneficial.

Specifically as it related to this community, talk to why you are interested in doing this, what are you trying to do?
Answer: Jira does not offer any native character count function. A few alternatives:

Export to CSV and filter the data in Excel
Use Jira API
Use ScriptRunner, as you can see here: issueFunction in issueFieldMatch("project = FOO", "description", "^.{0,10}$")

Now, more on the PM context: People using such small acceptance criteria are either very seasoned or very junior. Understand what's your case. Short acceptance criteria is a sympton, not a sickness. I'd avoid monitoring such criteria. Understand why such cases exist and deal with them. Do not consider any of the above approaches as something sustainable in the long run.


Does velocity of the exit gasses of a rocket affect visibility of the plume?

Question: A rocket moves under the conservation of linear momentum, where the gases formed inside it, exit through the nozzle, and in turn, the rocket moves forward. What I want to ask about is that: is it true that increasing the velocity of the issued gases would help in letting the gases be unseen by our eyes(or seen much unclearer) when looking at them flying in the atmosphere, as they are being issued in a diverging mode and not in a linear mode ?
Comment: I agree the question is hard to understand. I'd like you to restate it.
Comment: Can you [edit] to clarify what you mean by "appearing unclearer"? Are you talking about the visual distortion from the heat of the rocket plume, or something else entirely?
Comment: Sorry , I have edited it ,hope that its clear now
Comment: *as they are being issued in a diverging mode and not in a linear mode*: Are you implying that a greater exhaust speed results in a more divergent exhaust plume? I don't know anything about this, but I would like to see this assumption confirmed by someone, otherwise this sentence make no sense.
Comment: No, the nozzle of the rocket itself has a diverging shape at the end, so whether the exhaust gas is slow or fast , it will be issued in all directions
Answer: In the atmosphere, the answer is mostly no, because the exhaust gases slow rapidly when they hit the surrounding air. Increasing the exhaust velocity by a modest factor will diffuse the plume only a very small amount, and increasing it by a large factor will probably put enough energy into the surrounding air to make it incandesce.
Outside of the atmosphere, the exhaust velocity is high enough to diffuse the plume quite rapidly; you can see the difference in any SpaceX launch video between the first-stage exhaust and second-stage. The chemistry is the same for both stages and the exhaust velocity only modestly higher for the second stage, but the plume from the second stage burn is much fainter. You can also see over the course of the first stage burn that the exhaust goes from a tightly confined bright yellow plume at low altitudes to a fainter, more diffuse and orangey pattern at high altitude.


Filling in gaps in illustrator (by not using gap detection)

Question: I am trying to colour an image on adobe illustrator.
I initially "image traced" the image, so many of the strokes disappeared. I used live paint and direct selection to fill in the colours. However, now I am at the point of finishing my colouring, but there are gaps outside of my image that I can't fill.
I tried gap detection, it does not fill the gaps. I tried joining the strokes with the paths but then I can't colour within the region. How do I join the gaps and colour within it? I hope what I am asking makes sense.
(https://i.stack.imgur.com/kzGeM.jpg)
Answer: At some point one often needs to expand the artwork and manually correct or alter paths to gain the attain the desired appearance.
Object > Expand or Object > Expand Appearance
For a Live Paint Group, click the Expand button on the control bar across the top of the screen.


Prove $\cos((3\pi/4)+x)-\cos((3\pi/4)-x)=(-\sqrt{2})\sin(x)$

Question: Please help me to solve the below trigonometric function as i am trying it from the last hour.
$$\cos((3\pi/4)+x)-\cos((3\pi/4)-x)=(-\sqrt{2})\sin(x)$$
Answer: Apply, $\cos(A+B)-\cos(A-B)=-2\sin A \sin B$
So, $\cos(3\frac{\pi}{4}+x)-\cos(3\frac{\pi}{4}-x)=-2\sin x\sin(3\frac{\pi}{4}) $
$=-2\sin x\sin(\pi-\frac{\pi}{4})=-2\sin x\sin(\frac{\pi}{4})$
 as $\sin(\pi-y)=\sin y$
So, $\cos(3\frac{\pi}{4}+x)-\cos(3\frac{\pi}{4}-x)=-\sqrt2\sin x$
or apply $\cos 2C- \cos 2D=-2sin(C+D)sin(C-D)$
Put $2C=3\frac{\pi}{4}+x, 2D=3\frac{\pi}{4}-x=>C+D=3\frac{\pi}{4}$ and $C-D=x$
Answer: Probably you are meant to use the formulas $\cos(a+b)=\cos a\cos b-\sin a\sin b$ and $\cos(a-b)=\cos a\cos b+\sin a\sin b$. We could let $a=3\pi/4$ and $b=x$, and compute, then subtract, using the fact that $\cos(3\pi/4)=-1/\sqrt{2}$ and $\sin(3\pi/4)=1/\sqrt{2}$.
But it is much better to subtract first, as lab bhattacharjee did, because there is very nice cancellation, and we get
$$(\cos a\cos b-\sin a\sin b)-(\cos a\cos b+\sin a\sin b)=-2\sin a\sin b.$$
Now put $a=3\pi/4$ and $b=x$. Since $\sin(3\pi/4)=1/\sqrt{2}$, we get
$$-\frac{2}{\sqrt{2}}\sin x.$$
Finally, note that $\frac{2}{\sqrt{2}}=\sqrt{2}$.


Improper shutdown, now 3 flashes on boot

Question: I had to do a hard power off on my Pi, as it had crashed. Now, when I turn it on, I get 3 flashes of the OK LED, which means either loader.bin or start.elf is not found. I have plugged the SD card into my Windows PC to browse the boot partition and neither of those files is present. Is there any way to repair the boot partition and allow the Pi to boot without losing any data on the card? I have important data that hasn't been backed up yet on the card.
Answer: I'm afraid you're going to have to fix the installation manually.
You can download the relevant bin and elf files from the Raspberry Pi GitHub repository.
Then mount the boot partition of the SD card and copy the files onto it.
If this doesn't work then something more serious has gone wrong and you're going to have to re-flash the entire image.
However, you should be able to save your data if you can mount the SD card as you can simply copy off the files you want. They will be in the directory <code>/home/[username]</code>.
I hope this helps, let me know if you have any more trouble.
Comment: This is pretty much what I did, except instead of getting the files from github, I flashed a spare SD card with the latest Raspbian and copied the entire contents of the boot partition to the non-working card.
Comment: Good job. Hope I helped :)
Answer: You could:
Backup the card.
Reflash the card with your OS, which would also fix the boot partition.
Copy the files you want back to your card.


Method of reconstructing a band-limited signal from discrete samples

Question: I understand current cell phones use digital communications. Given that this industry brings in billions of dollars each year, there is much incentive to get the best performance possible. So what method of reconstructing an audio signal from discrete samples is normally used in a good cell phone these days? It seems there must be methods that work better than the ones I read about in text/reference books.
Comment: Strictly speaking this question requires an answer from someone who indeed has an access to **standards** (definitions and implementations) But, nowadays an observer can make the following deduction that as today's mobile communications market (4G,5G etc) is providing **video streaming** to its users, it seems they don't have a bandwidth restriction as **severe** as previous generations. Eventhough a minimum for speech is always the best choice, they seem to be concentrated on other features...
Comment: @Fat32, let me put it this way. I think at one time, there was an incentive to squeeze every bit of performance from a realitively small number of samples. Wouldn't that Have been the case in the early days of digital music and/or digital cell phones? All that aside, I want to know what is/are the best algorithms for signal reconstruction.
Comment: you are right... It was so, and I hope it is still so...
Comment: @TedErsek I would like to point out that the purpose of a DAC in a cell phone is arguably not to get out the "best performance possible". The components such as the loudspeaker and the microphone distort the signal far more than any DAC would (arguably). It would be wasteful to use a state of an art DAC on a cellphone.
Comment: @Dole, I think the industry strives to make cell phones and monthly bills as affordable as possible while also having good audio quality. They also want to make they cell phones small. Hence, the microphones and speakers are no better than necessary. Also, if it were not for cleaver compression, and DAC algorithms monthly
Comment: **** wasn't finish with my comment ***** If it were not for cleaver compression, DAC algorithms and possibly other tricks cellular phone service would be more expensive. I suspect the sample rates are low enough that non-trivial DAC algorithm(s) are needed to get good signal reconstruction.
Answer: Some recent cell phone models use something like a Cirrus Logic CS42xx series audio IO chip, which seems to use a digital polyphase interpolation filter, a sigma delta modulator, followed by a switched capacitor DAC and low-pass filter.
Sinc interpolation (or, given finite hardware, a polyphase FIR kernel similar to a windowed Sinc) is one high quality method of reconstruction from bandlimited samples.
But reconstruction isn't the main issue with respect to audio quality.  Quality or fidelity is more likely constrained by the audio data compression algorithm used (or required by standardization), and how much spectrum bandwidth is allocated by the comunications standard and regulations.
Comment: so, Ted, as hotpaw says here, the interpolation state-of-the-art is going to be something that looks like a windowed-sinc $$ x(t) = \sum_{n} x[n] \cdot h\left(t - \frac{n}{f_\text{s}} \right) $$ where $$h(t) =  w(t) \cdot \text{sinc}\left(f_\text{s} t \right)$$.  $w(t)$ might be a Kaiser window with $\beta \approx 5$ and with, say, 32 samples in the summation.  that's real clean and well defined.  and the real issue about audio quality in digital communications is the compression and expansion.
Answer: The general mathematical framework for interpolation is approximation theory. I guess the most important result is that for signals with bandwidth limitation, you can have perfect reconstruction via $sinc(\cdot)$ convolution; the famous sampling theorem, that has been mentioned here several times. I guess it is equally well-known that it is not really possible to implement this in practice, since it requires the entire signal before interpolation. The goal of any practical interpolation is to approximate the $sinc(\cdot)$ convolution, and to do so in an efficient manner. Good practical interpolation that I know about:

FIR filters: Computationally effective, especially when using the polyphase implementation, which reduces the computational complexity.
Splines: Any number of types of splines can interpolate a signal to an arbitrary precision by increasing the order. I seem to remember that the basis-function for B-splines actually converges to $sinc(\cdot)$ if the order goes to infinity. However, even a cubic spline provides a pretty good approximation to the $sinc(\cdot)$ function. A problem using splines on a stream is the choice of boundary conditions.
Convolution interpolation: This is similar to splines, but the kernel, or basis function, used in the convolution is chosen differently. I known cubic convolution has been applied in medical imaging.

These are to my knowledge the best practical interpolation methods. When you get to the physical layer of your phone, the DAC, there additional restrictions. Almost all DACs these days use can be modeled using zero-order-hold (ZOH), which is a special case of spline interpolation. It has the Laplace transform
$$
\text{ZOH}(s) = \frac{1 - \text{e}^{-\tau_{s} s}}{\tau_{s} s}
$$
which has a low-pass characteristic. Additionally, you would add an analog low-pass filter to the output as well. Here you a stuck with the standard topologies  (Sallen-Key, twin-T, state variable, ...) and pole-placement patterns (Bessel, Butterworth, Chebychev, ...). However, there does exists some exotic DACs that are not based on on/off of switching elements, but implements higher-order spline interpolation directly using analog integrators.
Now, do you really need a reconstruction filter? For audio, some people argue that you do not; the reason being that the repeated spectra that you are trying to remove are inaudible to the human ear -- the only reason would be to reduce the additional power consumption needed when trying to reproduce inaudible high-frequency content, and to limit any non-linear behavior such a slewing and saturations that might occur...


How do I get rid of shiny skin with Lightroom?

Question: For photos taken with my Point & Shoot camera, the flash often leave people in the photo with a 'shiny skin' effect. Other than not using the flash (or at least moving the flash off the lens-axis), what's the best way to reduce the shiny skin effect with Lightroom?
Answer: For this photo of my brother and his girlfriend, I used the brush with brightness set to about -10 or -20 (very subtle) with a large feather and the clarity at about -35%. This smoothed out any little specular bumps on their skin and brought down the shininess of the highlight themselves. I'm sure there might be better ways but I ended up with something that I think looks much better.
This was taken on a Canon 50D with the 18-55mm kit lens using the in-built flash.

Here's the original.
Answer: The old way of solving this problem, I mean before digital post-processing, was to apply foundation cosmetics on the model face. This is still used for TV shows.
Comment: Standard cosmetics don't necessarily reduce shine. You can buy anti-shine specifically for this task. It's a kind of clear gel that dries in seconds (though you can get it in colours too, but that tends to restrict its use). I always carry some in my bag.  Look for 'movie quality', 'camera ready' or similar in the advertising. It's not expensive & is invisible in use, so anyone can wear it.
Answer: Although you could fix this problem in lightroom with reasonable results, you can fix it when taking the picture.
The flash is too hard and overexposes certain parts of the face (and reflects in the eyes), a easy fix is to diffuse the intensity of the light, sometimes this is possible by tweaking the flash intensity but what always works is just put a piece of thin paper in front of your flash. I've advised this to some friends with a P&S and the results are very noticeable and some of them now have a white paper taped in front of the flash.
You should check that the warmth produced does not burn your paper, and if you have a popup flash, you could try the DIY diffuser using a old film canister idea.
Answer: Intriguing question. Only way I know how to solve this "well" is with a circular polarizer filter attached to the lens, however I am not sure if this is possible with a P&S.
If you wish to try fixing the problem somewhat with Lightroom, I would try using the selective editing brush (the last tool on the right under the histogram). With this tool, you can essentially "paint on" a variety of color and tone settings. You could try painting on "Highlight Recovery" just in the areas where you need it, leaving the rest of the image unaffected. I am not sure if this will solve the problem, and you might need to tweak some other settings such as color temperature and/or saturation, as recovery has the tendency to shift colors when a single primary (such as reds/yellows in skin tones) dominate.
Comment: Yeah I have found I can't really use the global Recovery setting when dealing with portraits or skin tones in general. It makes them a little pink and not too flattering...
Comment: You can usually compensate for that with adjustments to temperature and tint. The selective editing brush can brush on multiple adjustments simultaneously, so you might need to experiment a bit. The key is to recognize that recovery will try to recover only what is "blown", so if reds and yellows are considerably more blown our than blues and greens, you get a color shift. Simultaneous adjustments to temperature and/or tint along with recovery can usually correct that.


Should central bank raise interest rates during a condition of liquidity trap?

Question: I was studying about liquidity traps and understood it fairly well that according to widespread beliefs the monetary policy turns out to be ineffective as nominal interest rates are close to zero and the public has deflationary expectations. Since nominal rates are close to zero nobody wants to hold financial assets and prefer cash instead.
My question here is that in such a condition when nobody is investing in bonds, should not the central bank raise interest rates to give higher incentive to bond holders. I know I am missing some point but can someone please explain this relationship between interest rates, inflation and bonds in the context of liquidity trap.
Answer: In rough terms the central bank wants the nominal interest rates low so as a) to incentivize people to consume their income rather than save it and b) to make loans more attractive as they are linked with lower interest, thus bolstering consumption (again). During a crisis however, consumption remains low as expectations of economic growth deteriorate. Moreover, as interest rates are low, there is no point in saving money into the banks. Thus, people choose to hoard money, essentially removing it from the economy. With less money in the banking system and a generally pessimistic economic environment, banks become more skeptical towards providing loans as they doubt that they will get their investment back. All these processes empower the endurance of the vicious circle of the liquidity trap.
In theory, such prolonged periods of near zero interest rates would mean higher inflation. However, the recent crisis has proven that zero interest rates and stable inflation can co-exist. Therefore, the central bank has, up until now, been reluctant towards increasing the interest rates and in the past years it has made sure to inform the public that it is going to keep them quite low for some time (forward guidance). There is a whole debate of whether low interest rates are or should be linked with high inflation during financial crises and recently we see a drift, especially in the US, towards an interest rate increase even though it has not yet materialized.
Bonds are not considered a "go to" solution under a liquidity trap as their demand is really low. This stems from the fact that when a government faces a recession, its bonds are not considered a safe investment as they are paired with a high interest rate. Thus, the public awaits that they are unlikely to be honoured in the future. And if the recent financial crisis has taught us anything is that even bond holders are not safe.
Answer: A very good question, but first some clarifications.
The banking sector is unique from all other industries in that it creates its own liquidity.  Banks borrow short term low yield debt and invest in high yield long term assets.  The maturity mismatch that occurs in the aggregate is tremendous and not sustainable.  Banks are always reliant on individuals perpetually rolling over such short term debt as in the aggregate it can never be redeemed.
Many argue that such maturity mismatching is reckless and not responsible.  That banks should suffer the consequences when they gamble by with such outrageous maturity differences.  Instead the Fed makes the problem worse, by constantly guaranteeing a source of short term debt to constantly proper up long term assets banks have no business owning.
So you can't equate interest/investment with the economy at large with what banks do.  Banks are unique!  They're problems should not necessarily be our problems.
As for a liquidity trap...it is constantly happening and CB's like the Fed are constantly bailing them out by injecting short term debt into the fed funds market through the "open market".
Banks mostly rely on other banks for their sources of reserves.  When banks stop trusting each other, the money multipliers collapses and the means by which short term debt can be redeemed starts to vanish.  I like to think of this as a liquidity fire instead of a liquidity trap as the banks have promised more reserves than they have in the aggregate...and when they scramble to claim their chairs when the music stops, it will just make the problem worse.
When a central bank talks about interest rates approaching zero, they're not talking about real investments (like securities and mortgages).  They're just talking about the rate they are trying to manipulate banks to lend each other. Bank to bank debt. Given that such a rate is determined by bank trust, such a rate does not necessarily have to correlate to the greater market rate at all.
Raising the fed funds rate will great increase a liquidity trap (not necessarily a bad thing).  More bonds won't make a difference...the banking system's ponzi scheme is being exposed and they need more reliable short term assets...not long term like bonds.
Kind of a long answer...but I hope you found this somewhat helpful.  The question is important.
Comment: If I followed you correctly what you are saying is that the interest rate that governs bonds might not be the interest rate that approaches to zero in a liquidity trap. Thus, in a liquidity trap situation the central bank short term rate is almost zero which fails to stimulate the inter bank rates which are governed by trust. Bond rate might not be zero. What I didn't get is then why don't people hold bonds as it might still be giving some return and how is this distrust among banks and the inability of central bank to improve it gets translated to such a huge glut and recession in economy ?
Comment: The start of what you said is absolutely correct.  If the Fed Fund Rate (the rate at which bank charge other for short term debt) falls then this doesn't mean that bond rates will fall.
Comment: It really is more of a banking problem and bankers like to make it seem more like a non-banking problem to get more welfare.  Why don't banks hold bonds in a liquidity trap?  Because that isn't the problem...the solvency of their short term debt is. The public won't hold bonds because they aren't money.  You can spend checking deposits but not bonds.
Comment: Could you please have a look at another answer below by Arthur. He says that people hoard bonds (government bonds) in such times. Is there some difference between your answer and his answer.
Comment: The relationship between a liquidity trap and public bonds is complex.  On one hand money is being literally destroyed.  Less money to buy bonds = lower priced bonds.  On the other hand banks are desperate for short term assets during a liquidity fire and will sell long term assets on the open market.  Lower priced long term assets will hurt a banks credit rating and force it sell even more.  So it is IMO a liquidity crisis will result in very cheap bonds.
Answer: Cash and bonds are almost identical from financial and economic perspective. Most institutional investors and banks keep much of their cash in bonds. Physical cash is becoming a bit obsolete so the notion of "hoarding cash" no longer means taking out bags with dollar bills and stuffing them under the mattress or into the safe box. Hoarding cash nowadays is pretty much moving money from equity to bonds or cash accounts, but not taking out physical bills, like it may have been before digitalization of financial markets. So in a liquidity trap you will have everyone practically "hoarding bonds". Increasing interest rates in such situation will cause even more money to move out of the equities into bonds and exacerbate deflation. That is what has been happening to Japan and arguably happened in the US in 2009 when Fed responded with setting rates to ~0 and buying back about a trillion dollars worth of bonds (QE). However, liquidity traps are hard to define empirically. Any situation where you have rates near zero and inflation near zero or deflation, can be argued to be a liquidity trap.
Comment: I actually found your answer contradictory to what I read in standard textbooks say, " during liquidity traps the interest rates are close to zero hence people don't prefer to hold bonds as bond prices are too high and they are expected to certainly fall thereby giving a loss in capital. Any attempt by central bank to infuse more liquidity is futile as any amount of additional liquidity will be absorbed at the prevailing interest rate." I am really puzzled. If everyone is holding bonds then the firms issuing those bonds must be having money to invest. Then how is the liquidity trapped. Puzzled
Comment: @AbhinavArya The central bank's key interest rate does not (directly) affect corporate bond yields. Corporate bonds are a whole another story. Corporate bonds market is rather tiny compare to government bonds one. They usually refer to US treasuries as "bonds". Can you link the title and author of that book? My guess is it is either pre-2008, by an unknown author, or both.
Comment: I think I got your point when I relate it to the different interest rates prevailing and higher interest rates on corporate bonds owing to higher term and risk premium due to declining investor confidence. Maybe the author was referring to something else.
FYI: Book Title : Principles of Macroeconomics by Soumyen Sikdar, Oxford University Press India. The author says what I quoted in my previous comment.
Comment: The book is published in 2006 so the author had no knowledge of a string of successful anti—deflation policies by Fed, ECB, Bank of England, and Bank of Japan post 2008. Just think of that sttement as somewhat correct at the time but outdated now.


Selenium IDE - Actual use- seeking a practical example

Question: What is the actual use of Selenium IDE?
Apart from playback and record How can we use this tool to check the validations of a simple login form in website?
Answer: Yes, you can do validations using either verify or assert.
Check this documentation which will give you a clear idea -
http://docs.seleniumhq.org/docs/02_selenium_ide.jsp
For complex automation, you need to use Selenium WebDriver which gives you flexibility to code.
Answer: I used the Selenium IDE extensively on my last project. I had a suite of tests in a test domain specific language and a translator that created Selenium IDE test suites. When I left the project, there were more than 700 tests in the suite.
a) The test DSL was originally written in XML, based on a number of other test DSLs I had created for other projects. The test DSL was originally built to generate test scripts for humans to follow. When Selenium IDE came to my attention, it was quite simple to repurpose the translator to create Selenium IDE files. Several hundred test scripts were re-used.
The translator was an XSLT script, and bundled the individual test cases into test suites. Near the end, I rewrote the DSL and the translator into Perl, for much improved performance and readability. I looked seriously into rebuilding the process in Java but the incremental improvement in test coverage and browser coverage weren't justified.
b) The test DSL was actually generated from a bunch of spreadsheets, using a template language, translated by an XSLT script (then Perl).
c) Multiple data sets resulted in multiple files. A change to the UUT user interface required changing one master file for a form, and then regenerating the test suite.
Months after leaving the project, I still consider the Selenium IDE a godsend for UI test automation.
Answer: From the answer of @Bob Dalgleish you can see that output of Selenium IDE is quite hard to use. get XML, transform it with XSLT and Perl? No thanks!
IDE is useful to show locators, but test it generates are too linear and will repeat big chunks of code, as if they were copy-pasted. So if any change is made, chances are exactly the same change will need to be made in very many places. To avoid this, competent automated testers design test using PageObject pattern in their favorite programming language (which for me is Python).
As a result, I have very little use of Selenium IDE. If your fronted designer is competent, UI elements have ids, and "inspect element" will reveal it - that's all you need to know about it. Rest is code.
I prefer this approach possibly because I came to test automation with development background, so writing code was "normal" for me, and Se IDE was not helping much in accomplishing that goal. I don't want to maintain hundreds of lines of boilerplate generated code. If I did, I would be using Java :-)
Comment: Toward the end of my time on that project, we seriously considered re-coding the tests in Java. I even had built a translator that would directly generate Java/WebDriver test code but didn't finish it. There were other benefits to the DSL, including the ability to generate human readable tests for parts that were not easily automatable (checking alignment of fields, graphics rendering, etc.)
Comment: Even Java/WebDriver generated code will not help you because it is **still** plain old linear step-by-step interactions. To improve coder's productivity, your tests need PageObject, and such redesign and refactoring cannot be generated yet.
Comment: That still wasn't my point. Each of my test cases started at the beginning, filled out fields, checked status displays, submitted the form and tested the result. I already had the DSL, the data and the approach.
Comment: While the big push is definitely towards PageObjects and more flexible, code driven tests, there's still a lot of value to the IDE.  I can't find the video now, but I remember there was one a few years back about some web retailer that got a lot of bang for the buck having lower skilled testers using the IDE to record tests.  Maybe a bit of a brute force approach, but it worked for them.
Comment: Test recorded in IDE cannot be changed or parametrized. So i.e. you cannot just add one more order, locate it's number, and work with that. You have to start with known database, and run canned test in the same order, to have the same IDs of orders or whatever. And you cannot fill current date in IDE unless you have a widget to enter current date. So yes, you can do **some** testing in IDE end rerun recorded test but you can test only very limited functionality. I agree that usability of IDE is not zero but it is a small number.
Answer: A practical use of the seleniumIDE is testing your web site works correctly in firefox.
You use commands such as
assertElementPresent
assertBodyText
assertConfirmation
assertNotChecked

to verify page contents
Generally you should avoid record and play (generates brittle tests that break easily as soon as the page is changed) and learn how to write good use of selectors yourself.
As you advance you should look to use a PageObject model approach which IS supported by the IDE - just use the load javascript file from the 'options' tab.

and put your page object descriptors in that file.
Example format of that file:
storedVars["css_violation_submit_form_input"] = "css=form.new-violation input[type=submit]";
storedVars["css_claim_submit_form_input"] = "css=form.new-claim input[type=submit]";
storedVars["css_driver_submit_form"] = "css=form.new-driver *[type=submit]";
storedVars["css_vehicle_submit_form"] = "css=form.new-auto *[type=submit]";

Part of a practical example is shown here from a site for car insurance quotes with forms being filled out and asserts being done.
Answer: What we do is use the Selenium IDE to record scenarios, then save as Webdriver python scripts. The code in webdriver flavour is pretty readable and you can then modify the scripts as needed. You can use the IDE to add assert/verify or just add it in the scripts yourself. Then we use Robot Framework to drive these test cases, linked to Jenkins then you get yourself a low-cost automated testing. This won't cover 100% of your test plan but it has a very low technical requirement, so even the newest guy in QA can start to be productive within a day or less.


Software download from windows os

Question: Could i search and download ubuntu's packages using windows OS.
If can then please tell me, whats the website.
many thanks.
Answer: I suppose you want to download packages that will be later installed on a Ubuntu machine. The official Ubuntu repository can be accessed over the net at http://packages.ubuntu.com/. You can download .deb packages in that website and install it with dpkg -i on the Ubuntu system.
Answer: All of the ubuntu packages?  Sure, just download the disk image and extract it.
www.ubuntu.com
Answer: You can search the packages here.
Once you're on the package page, you can navigate between versions (lucid, precise, quantal, raring) on the top right and you'll find the .deb download links on the bottom. (click on your architecture and choose a mirror to download from)

Software download from windows os


Has there been a headless state?

Question: Has there been a state without an office satisfying the definition of a head of state? This question is mostly about the modern times because I'm not sure if we can give a satisfactory definition for outdated political systems. Please feel free to comment on this, but still the main focus of this question is on the modern world.
Comment: Would Andorra count? It has two heads of state, together (the co-princes).
Comment: @myself forget that, in [December 1967](https://en.wikipedia.org/wiki/Harold_Holt#Disappearance), Australia not only lacked the head, but the entire body!
Comment: I'm sure I could google some headless heads of state. Would that count?
Comment: @Andrew That was the Head of Government, though, not the Head of State!
Comment: If I recall correctly, most members of the state lost their heads during the French Revolution!
Answer: Switzerland lacks a single head of state, though the members of the 7-head government take it in turns to represent the country as such abroad during the 7-year government term. See also Wikipedia on Politics of Switzerland.
Answer: While the U.S. was under the Articles of Confederation, the President of The United States in Congress Assembled was not a head of state. Instead, the role was to ensure impartiality of the congress and enforcement of rules. Articles of Confederation, Presidents of the Congress
Answer: In the USSR the head of state was collective: the Presidium of Supreme Council. The state was usually represented and laws signed by the Chairman of the Presidium, but he actually did not have any powers: if he would refuse to sign a law for instance, it would be signed by his deputy.
Answer: Since 1974, The Socialist Federal Republic of Yugoslavia (SFRY) had a collective head of state, the Presidency.
It was usually represented by a chairman, a rotating position between the republics and SAPs.
Answer: I think, Bosnia doesn't have a single head of state. There is a 3 member committee consisting of ethnic serb, ethnic croat, and ethnic Bosniac member each.
The committee has a chairman, and he becomes a chairman by rotation.

Has there been a headless state?