text:
12:40 AM
@barbarabeeton Thank you!

7 hours later…
8:05 AM
@barbarabeeton @PauloCereda is acquainted with every video on youtube.
5
Fix one bug, spend the next 27 years adding more:
1

You have good memory, the change predates LaTeX2e but in the latex sources you find... \begin{macro}{\@gnewline} \changes{v1.2u}{1996/10/29}{Added macro} The |\nobreak| added to prevent null lines when |\\| ends an overfull line. Change made 24 May 89 as suggested by <NAME> and ...

@cfr The question was about using Green's theorem (with plenty of hints) to derive d'Alembert's formula for the solution of the one-dimensional wave equation. I had just been reading about the wave equation in a different context, so I already knew the formula. (But this derivation was new to me.)

9:14 AM
@cfr He was part of a comedy duo with a bloke named <NAME>. They were so awesome! Donald was a linguist and pianist. :)
@barbarabeeton I blame <NAME> and <NAME> for introducing them. :)
@DavidCarlisle ooh that's quite accurate

3 hours later…
11:46 AM
Quaaaaaack!

12:18 PM
@PauloCereda /me enjoying the holiday ;-)

12:34 PM
@egreg oooh :)

1:05 PM
@PauloCereda Boo!!!

@yo' Tom! <3

@PauloCereda how do you do?

@yo' Fine, and you? :)

@PauloCereda busy but well :-)

@yo' Yay!

1:16 PM
@PauloCereda you know the feeling when you have a nice arrangement of some carol, but it's low tone is D and the sax you'll play with is an Eb one? ...

@yo' Oh my

@PauloCereda in other words, transposing from a nice G major to Ab major :-/ lots of LilyPond fun and lots of troubles playing
it's Adeste Fideles if you were interested, with a British style descant

@yo' Ouch. :(

Given a \NewEnviron env, say, test, how can I test if \BODY corresponds to a blank line? (it seems it catches \par ). I'm attempting to use etoolbox to test (I'd prefer not to use expl3 here). Ideas?

@yo': could you transpose the Clavinova?

1:20 PM
@PauloCereda you mean the pipe organ? :D

@yo' ooh let's find a way. You might need a hammer. :)

And no, I can't actually play a transposed piano. My hands shift spontaneously when I do that.
@PauloCereda you know that an organ is tuned by bending the pipes' ends in or out to decrease or increase the pitch? And when the pipes' ends are worn out, teared etc., all the pipes are shortened, thus increasing the organ's pitch?

@yo' how nice!

@PauloCereda well, not nice, it's difficult to tune organs to basically anything :-( and one organ I played recently has an Oboe register that is in tune only in winter, in summer it's completely out of tune...

1:38 PM
@daleif \ifx\BODY\foo yes \else no\fi where \foo is defined to be whatever \show\BODY says in the case you want to be yes, probably \long\def\foo{\par}

1:59 PM
@DavidCarlisle Does not seem to work well, I have something that sort of work with etoolbox, but I have to hide it in a savebox (bad user, bad user)

@daleif What does \show\BODY give in your case?
@DavidCarlisle I'm (almost) in your part of the world (Didcot)

@JosephWright Seems to be just give \par  (hmm, my etoolbox hack did not work on real life data)

@yo' -- when <NAME> was in providence last week (cs.brown.edu/events/kanellakis/knuth) he got to play two local organs, one at the cathedral of saints peter and paul, and the other, the university organ in sayles hall (brown.edu/Administration/News_Bureau/2003-04/03-022.html and today.brown.edu/articles/2009/03/organ-0). that is quite a fine organ, and is kept in good trim. we got to visit the pipe chamber last year. wonderful!

@JosephWright This is a hack that almost work, but bad code (fails if is uncomment the two lines)
\documentclass[a4paper]{memoir}
\usepackage{environ,etoolbox}

\newsavebox\hst
\newtoggle{isEmpty}
\NewEnviron{hest}{%
\sbox\hst{
\begin{minipage}{\textwidth}
\ifdefvoid{\BODY}{%
\global\toggletrue{isEmpty}
}{
% \expandafter\ifdefequal\expandafter{\BODY}%
% {\par}{\global\toggletrue{isEmpty}}{}
}
\end{minipage}
}
\iftoggle{isEmpty}{\emph{is empty}}{
\BODY
}
\par\global\togglefalse{isEmpty}}

\begin{document}

\begin{hest}

\end{hest}

\begin{hest}
% hest
\end{hest}

\begin{hest}
brian

@barbarabeeton opening the pipe chamber is better than unpacking Xmas gifts!

2:09 PM
Probably a bit more relevant:
\documentclass[a4paper]{memoir}
\usepackage{environ,etoolbox}

\newsavebox\hst
\newtoggle{isEmpty}
\NewEnviron{hest}{%
\sbox\hst{
\begin{minipage}{\textwidth}
\ifdefvoid{\BODY}{%
\global\toggletrue{isEmpty}
}{
\ifdefequal{\BODY}{\par}{\global\toggletrue{isEmpty}}{
\typeout{non empty}
}
}
\end{minipage}
}
\typeout{hest}
\iftoggle{isEmpty}{\emph{is empty}}{
\BODY
}
\par\global\togglefalse{isEmpty}}

\begin{document}
\typeout{1}
\begin{hest}

\end{hest}

\typeout{2}
\begin{hest}
% hest
\end{hest}

@daleif You want \def\temp{\par}\ifdefequal{\BODY}{\temp}

@JosephWright thanks, I'll try it on my real data

@yo' -- yes, it really is. when i was in denmark some years ago, attending an iso working group meeting, the chair of the group (who is an organ fancier) arranged for just a few of us to visit a castle that had a working box organ. the air supply was provided by three bellows behind the organ, each operated in sequence by pulling down on a rope. and after his concert, the organist opened the pipe chamber to show us what was inside. nothing large, of course, but just magnificent!

@JosephWright woo, works, much better interface for my form
Next year, I'll make this as a web form instead (using LaTeX or Word for this in not a good idea)
@PauloCereda might want to pick your brain for some web stuff sometime

@barbarabeeton when you come here, I can show you the (probably) only English baroque organ in the Czech Republic :) It's actually just a positive, but still, beautiful :-)
anyway, gotta go now, see you later!

2:23 PM
@JosephWright isn't that same as my \ifx suggestion? :-)

@daleif Feel free to poke me any time. :)

@DavidCarlisle Yes
@DavidCarlisle Mine was obviously clearer ;-)

@PauloCereda thanks

2:49 PM
@JosephWright If there are two blank lines…

@egreg then you blame the OP for having given an incorrect problem specification.
@Johannes_B so if I take a long name then there is a good chance that it does not clash with an existing definition \def\DeclareTextCompositeCommand{} should be good then?

3:14 PM
@barbarabeeton anyone else, you asked I ping you if the videos of Sebastian's memorial meeting were available, You may have seen Frank's post to latex project site but:

@DavidCarlisle -- thanks. (frank did circulate this info to a list, including me. well worth watching.)

@daleif Is this what you want?
\documentclass[a4paper]{memoir}
\usepackage{environ,etoolbox}

\NewEnviron{hest}{%
\ifdefempty{\BODY}{\typeout{empty}}{\checkblanklines\BODY}%
}
\makeatletter
\newcommand\checkblanklines[1]{%
\expandafter\check@blanklines#1\check@blanklines
}
\def\check@blanklines{%
\@ifnextchar\check@blanklines
{\typeout{empty}\@gobble}% remove the last token
{\check@par}%
}
\def\check@par{%
\@ifnextchar\par
{\expandafter\check@blanklines\@gobble}%
{\typeout{not empty}\@gobbleall{\BODY}}%

3:35 PM
@barbarabeeton yes it was quite an inspiring meeting really

@egreg Something like that yes. So far this has worked fine in my real doc:
\ifdefvoid{\BODY}{%
\global\toggletrue{isEmpty}%
}{%
\def\foo{\par}%
\ifdefequal{\BODY}{\foo}{%
\global\toggletrue{isEmpty}%
}{}%
}%

@daleif Try with two blank lines

@egreg argh, well did not say it was perfect. The file is meant to be filled in by the user, not left blank, just wanted to leave a nice interface so it behaves when it has no data yet (I'm using envs for all data entries)

I don't suppose anyone here is fluent in SVG? :(

3:50 PM
@SeanAllred I only speak duck. :)

@SeanAllred Not really, but I've gotten some use out of the data

What is the problem

I'm trying to make a custom card deck for my girlfriend (proposing in two weeks!! D:) but I'm having trouble centering the suit on the card for the ace

@SeanAllred oooooooooooooooooooooooh

3:53 PM
uhh, hope she does not read chat

@daleif she probably has no idea this exists XD

@daleif Let us make sure she will read it. :)

@SeanAllred hehe

I tried to enlighten her to the ways of TeX, but she remains in the darkness

What are you using to make the SVG?

3:54 PM
@daleif emacs

@SeanAllred oh no

:P that is, I'm doing it by hand

@SeanAllred OH NO

clearly the solution is to use tikz!

the graphical tools aren't precise enough and I can't get a good center
@Maeher I thought of that XD it's at least something I'm more familiar with

3:55 PM
@SeanAllred Maybe Inkscape could help, then you could clean the source afterwards.

@SeanAllred Have you tried inkscape? And then perhaps figure out from there how centering works

@PauloCereda Also tried that

WE MUST HELP SEAN

The source is disgusting first of all and I can't make complicated documents

I cannot wait to wear a tuxedo!

3:56 PM
My SVG is now literally too complicated for graphical editors to handle

@SeanAllred Scroll up in the history for my conversion of a TrueType font into tikz, just using the SVG data

But hey, if someone wants to create a deck of cards with TikZ, there's a case of beer in it for you.

Sounds strange that Emacs can handle it but not inkscape

@daleif Well emacs is editing the SVG; firefox is rendering

3:57 PM
@SeanAllred HOLD MY BEER

@PauloCereda Shouldn't that be duxedo?

@AlanMunn ooh I see what you did there. <3

The main thing I'm using that seems too complicated is xlink:href

@PauloCereda the correct term is: Hold my beer; watch this y'all

@daleif ooh
If there's liquor involved, I think it's time to summon @percusse.

3:58 PM
@SeanAllred Please don't tempt me, I have slides I should be working on :P

@Maeher I have a thesis. I blame this people. :)

@Maeher a case of beer (or pizza (or …))
I'm desperate

Hey, I'm at work, but still here.

@PauloCereda Same goes for you.

@PauloCereda see, my thesis is done, but I still need to defend it ;)

3:59 PM
Do you have some data we can play with?

6

How to draw the cards from a deck using a Latex package, as TikZ?

@SeanAllred: ^^ something to begin, perhaps?
HOLY DUCK
 texdoc setdeck

@PauloCereda I love this game!!

@SeanAllred <3

4:01 PM
And what exactly is wrong with the cards?

@PauloCereda Perhaps, but I have vectors for the face cards and the suits (and a ver special vector for the ace of diamonds)
@daleif the ones on google code?
They're not uniform; they're misaligned, etc.

@SeanAllred ooh

@PauloCereda basic idea:

@SeanAllred you still have time to switch to an enlightened partner

@SeanAllred yes, they are not stable at all. Numbers are jumping

4:04 PM
@DavidCarlisle XD I think I can live with this one :)
yeah

@SeanAllred as long as she doesn't use vim you'll be fine

@DavidCarlisle you are mean. :) Could be worse: she could be a vim user.

@DavidCarlisle We had a close call with that one but I showed her the light of Emacs :)

I'd probably grap the basic shapes designs and the designs for jack, queen and king, and then redo this in tikz. There seems to be too much fiddling to fix those number placements, not enough programming.

@SeanAllred I prefer this one

4:08 PM
@DavidCarlisle The Chance is not as high.

@egreg I don't recognize that – what is it?

@Johannes_B I would say the chance of that long name clashing is around 100%

I do recognize 'treviso'; I think that's the name of the airport I landed in
Or the city where the airport was

@SeanAllred “Asso di denari” (which corresponds to the ace of diamonds) in our traditional cards.

@egreg very ornate :)

4:10 PM
@SeanAllred Treviso is a city, not far from where I live (about 40km)

@SeanAllred when he's not chatting here @egreg spends his time shuffling tarot cards in fairground tents telling fortunes.
3

@DavidCarlisle LOLOL
@David: you are mean. :)

@SeanAllred Here are all four aces:

@DavidCarlisle Hah!!

@egreg tried your solution. Now somehow I sometimes get repeated data, shouldn't your code completely eat up \BODY?

4:13 PM
@daleif Didn't do much testing.

@PauloCereda recognise the emblem ^^^ ?

@DavidCarlisle I only use my crystal ball for guessing the meaning of some questions on the site.

@DavidCarlisle E.g. "You got the death card. I see one of @DavidCarlisle 's packages in your future".
2

@egreg Seems, changing \long\def\@gobbleall#1#2\check@blanklines{#1} to \long\def\@gobbleall#1#2\check@blanklines{} works. No idea if it is correct.

@DavidCarlisle oh

4:17 PM
@daleif An example of doubling?

!!/help
@PauloCereda Psmith, the TeX bot: Good afternoon! I'm Psmith, the friendly TeX bot - the p in my name is silent, as in pshrimp. I'm here as a companion to our fellow users in the typographic land. As you probably noticed, I always reply under Paulo's account, but do not despair, I say, my replies are always preceded by my own name. Enjoy your stay at TeX.sx! If you need any help, just ask our chat residents. Cheerio!
@DavidCarlisle: guess who's back. :)

@egreg I'm using the test to set a flag, not to typeset \BODY that comes later.

@daleif Then you don't want \BODY there, but just to gobble everything up to \check@blanklines, so no argument is good.

@egreg it seems to be working

!!/battle
@PauloCereda Psmith, the TeX bot: The current score is egreg 215 vs. 205 David. So far, egreg is winning.

4:22 PM
@PauloCereda Nice to see Psmith is back!

@egreg At least, I've passed it on to the secretary who commissioned it

@egreg <3

!!/fortune

!!/cricket

4:23 PM
Psmith, the TeX bot, in fixed font mode: Let's take a look at the last cricket results:

- Tasmania 203/10 &  387/9  v Victoria 319/8 &  230/10 *
- Western Australia 265/10 &  227/2 * v Queensland 353/10 &  138/10
- Baroda 138/4 * v Uttar Pradesh 481/10
- Gujarat 307/10  v Tamil Nadu 78/1 *
- Mumbai v Punjab 434/6 *
- Delhi 237/10  v Saurashtra 92/10 &  37/2 *
- Karnataka 251/5 * v Maharashtra 163/10
- Rajasthan 140/10  v Vidarbha 116/10 *
- Andhra 190/10  v Hyderabad (India) 49/4 *

Apparently I understand so little about cricket that I cannot even come up with a way of interpreting those results

@Maeher Apparently it is some people, usually dressed in white, running around for days on a field playing a some sticks and a ball

@daleif That about sums up my understanding of it

4:38 PM
The Tikz reimplementation is going well. thanks for bringing me back to sanity, folks :)

@SeanAllred <NAME>

@PauloCereda did you say Psmith was around to check battle status (just asking...)

@DavidCarlisle yep :)

5:07 PM
!!/battle
@PauloCereda Psmith, the TeX bot: The current score is egreg 215 vs. 210 David. So far, egreg is winning.

@PauloCereda Where is the booze

@DavidCarlisle That one in particular, yes.

@percusse: it's a big project, he will propose!

@egreg -- you've got mail.

5:18 PM
\advance\beer by \shot{\jagermeister}
\let\jagerbomb\beer
3

@percusse oh

Then after a few of those .... \leavevmode

!!/choose jagermeister, beer
@PauloCereda Psmith, the TeX bot: The great oracle says: beer

!!/answer How old are you really?

@percusse Psmith, the TeX bot: I'm deeply sorry, old chap, but the command ask does not exist.

5:21 PM
aah

@percusse Psmith, the TeX bot: Good afternoon! I'm Psmith, the friendly TeX bot - the p in my name is silent, as in pshrimp. I'm here as a companion to our fellow users in the typographic land. As you probably noticed, I always reply under Paulo's account, but do not despair, I say, my replies are always preceded by my own name. Enjoy your stay at TeX.sx! If you need any help, just ask our chat residents. Cheerio!
I think it's !!/answer :)
Unless Wolftam Alpha changed the API. :)
Psmith, the TeX bot, in fixed font mode:

really  (English word)
1 | adverb | in accordance with truth or fact or reality
2 | adverb | in actual fact
3 | adverb | in fact (used as intensifiers or sentence modifiers)
4 | adverb | used as intensifiers; “real” is sometimes used informally for “really'; rattling” is informal
5 | interjection | used to indicate surprise at or requesting confirmation of some new information; used to express skepticism; indicating that what was just said was obvious and unnecessary, used as an expression of contrived incredulity

Psmith, the TeX bot, in fixed font mode:

How old is Wolfram|Alpha?
7 years 6 months 24.14 days
(right now)
394.5 weeks
66279 hours
3.977×10^6 minutes
2.386×10^8 seconds

!!/answer Why don't you act like an 7 year old then?

Psmith, the TeX bot, in fixed font mode:

7 years (age)
84 months
365 weeks
2555 days
61320 hours
3.679×10^6 minutes
Psmith, the TeX bot, in fixed font mode:

Tell me a joke.
Q: What do you call a young eigensheep?  A: A lamb, duh!
(according to what passes for mathematical humor (my favorite sub-genre), drawn from several sources but primarily from <NAME> and <NAME> in their paper "Sampling of Mathematical Folk Humor" in Notices of the American Mathematical Society, vol. 52, pp. 24-34, 2005)

5:24 PM
ufff,.... that hurt

:)
!!/eightball Should I work on my thesis?
@PauloCereda Psmith, the TeX bot: The great 8-ball says: outlook not so good.

!!/play Metallica - Sad but true

@percusse Psmith, the TeX bot: here

nope I'm not clicking that

@percusse this time was for real. :)
!!/eightball should Sir click the link?
@PauloCereda Psmith, the TeX bot: The great 8-ball says: my sources say no.

5:26 PM
well, you can't be too careful. I don't want to sing it for another 6 hours in my head

Stupid bot.

ahaha

@barbarabeeton You too.

@PauloCereda oi

@DavidCarlisle <3

6:03 PM
Could you elaborate on why you see “you have an old version, update” as being a close reason, rather than an answer? It’s a good solution to the OP’s problem. It looks like an answer, it quacks like an answer… — <NAME> 4 hours ago
@PauloCereda ^^^ A duck!

6:43 PM
@JosephWright ooooooh :)

7:14 PM
@percusse I set a beer bounty on a TikZ deck of french playing cards with a few customizations that I can set post-hoc
3 hours ago, by <NAME>

2 hours later…
9:03 PM
I seem to remember a post that resulted in Beamer code that automatically compiled a PDF displaying all of the color options along with their names; this created an easy reference for modifying particular colors in a given template. I can't seem to find this, does anyone know where it might be?

@Richard I blame @barbarabeeton for the variant spellings

@DavidCarlisle -- hmmmmph. the spelling of "color" happened long before i came along. blame noah webster.

@barbarabeeton Too complicated, It's simpler just to blame you for American spellings and weird American squiggles claimed to be a G

9:26 PM
@DavidCarlisle -- oh, okay. then i can blame anything that's clearly british on you, including badly hyphenated words. makes explanations a lot easier!

@barbarabeeton not badl-y hyp-henated, just hyphen-ate-d acco-rding to ru-les that are not clear in count-ries that don't speak p-roper english like what we do

2 hours later…
11:13 PM
what should the log be for the following. answers on a postcard to....
\scrollmode

\ifx\primitive\undefined
\let\primitive\pdfprimitive
\fi

\expandafter\show\primitive\zoopla

\expandafter\show\primitive\hfill

\end
@JosephWright, @egreg ^^

@DavidCarlisle \pdfprimitive is not always expandable.
If the control sequence was initially expandable, \pdfprimitive expands either. Otherwise \pdfprimitive doesn’t expand.

11:52 PM
@DavidCarlisle This is even funnier:
\scrollmode

\ifx\primitive\undefined
\let\primitive\pdfprimitive
\fi

\expandafter\show\primitive\if

\expandafter\show\primitive\hfill

\end`


text:
# Matching Supply with Demand

## Quiz 5 :The Link Between Operations and Finance

Question Type
(Crazy Cab) Crazy Cab is a small taxi cab company operating in a large metropolitan area. The company operates 20 cabs. Each cab is worth about $20k. The metropolitan area also requires that each cab carry a medallion (a type of license). Medallions are currently traded at$50k. Cab drivers make $8 per hour and are available for every time of the day. The average cab is used for 40 trips per day. The average trip is three miles in length. Passengers have to pay$2 as a fixed fee and $2 per mile they are transported. Fuel and other costs, such as maintenance, are$0.20 per mile. The cab drives about 40 percent of the distance without a paying passenger in it (e.g. returning from a drop-off location, picking up a passenger, etc.) a. Draw an ROIC tree for the cab company. b. Populate the tree with numbers. Make assumptions to explore operational variables in as much detail as possible (e.g., assumptions about gas prices, gas consumption, etc.). c. Which of the variables would you classify as operational value drivers d. Analyze the labor efficiency and the efficiency of using the fleet of cabs using productivity ratios.
Free

There is no answer for this question

Tags
(Penne Pesto) Penne Pesto is a small restaurant in the financial district of San Francisco. Customers order from a variety of pasta dishes. The restaurant has 50 seats and is always full during the four hours in the evening. It is not possible to make reservations at Penne; most guests show up spontaneously on their way home from work. If there is no available seat, guests simply move on to another place. On average, a guest spends 50 minutes in the restaurant, which includes 5 minutes until the guest is seated and the waiter has taken the order, an additional 10 minutes until the food is served, 30 minutes to eat, and 5 minutes to handle the check-out (including waiting for the check, paying, and leaving). It takes the restaurant another 10 minutes to clean the table and have it be ready for the next guests (of which there are always plenty). The average guest leaves $20 at Penne, including food, drink, and tip (all tips are collected by the restaurant, employees get a fixed salary). The restaurant has 10 waiters and 10 kitchen employees, each earning$90 per evening (including any preparation, the 4 hours the restaurant is open, and clean-up). The average order costs $5.50 in materials, including$4.50 for the food and $1 for the average drink. In addition to labor costs, fixed costs for the restaurant include$500 per day of rent and $500 per day for other overhead costs. The restaurant is open 365 days in the year and is full to the last seat even on weekends and holidays. There is about$200,000 of capital tied up in the restaurant, largely consisting of furniture, decoration, and equipment. a. How many guests will the restaurant serve in one evening b. What is the Return on Invested Capital for the owner of the restaurant c. Assume that you could improve the productivity of the kitchen employees and free up one person who would be helping to clean up the table. This would reduce the clean-up to 5 minutes instead of 10 minutes. What would be the new ROIC d. What would be the new ROIC if overhead charges could be reduced by $100 per day Free Essay Answer: Answer: The Return-On-Invested Capital (ROIC) for a capital investment scenario can be defined as the following expression: Where, the 'return' is to be computed by deducting all the expenses from the sales for a given period which is generally taken as one year. a. Use Little's law to compute the flow rate where the Work-In-Process (WIP) and Flow time is known. In this case, the WIP is the number of seats available which is 50. The flow time is the overall time spent per customer in the restaurant. This includes the 50 minutes of waiting, food serving, eating, and checking-out time plus the 10 minutes of cleaning activity i.e. a total of 60 minutes. So, from the Little's law: So, Since the working time for the restaurant in a typical evening is 4 hours, the number of customers served in an evening b. Compute the sales per evening by multiplying the number of customers served per evening by the average payment by a customer. So, The cost per evening includes the wages, material cost, rent, and overhead. The rent and overhead cost per day are both$500
So,
It is given that the capital invested is $200,000. So, So, the ROIC is c. The cleaning time reduces from 10 minutes to 5 minutes leading to reduction of flow time from 60 minutes to 55 minutes. So, from the Little's law: Since the working time for the restaurant in a typical evening is 4 hours, the number of customers served in an evening So, Other costs remaining the same, the material cost will be as follows: So, the ROIC is d. Keeping all other parameters the same, the overhead changes from$500 to $400 per day (the reduction is$100 per day).
So,
So,
So, the ROIC is

Tags
(Philly Air) PhillyAir Inc. offers low cost air travel between Philadelphia and Atlantic City. Philly Air's invested capital is $5,000,000, corresponding to the investment in the two planes the company owns. Each of the two planes can carry 50 passengers. Each plane does 12 daily trips from Philadelphia to Atlantic City and 12 from Atlantic City to Philadelphia. The price is$100 for each one-way ticket. The current load factor is 70 percent (ie., 35 seats are sold on the average flight). The annual cost of operating the service and running the business is $60,000,000 (including all costs, such as labor, fuel, marketing, gate fees, landing fees, maintenance, etc). The company operates 365 days a year. a. Draw an ROIC (return on invested capital) tree for the company that incorporates all of the above information. b. What is the current ROIC c. What is the minimum load factor at which the company breaks even d. What load factor would the company have to achieve so that it obtained a 10 percentage-point increase in the ROIC (e.g. an ROIC increasing from 5 percent to 15 percent) Free Essay Answer: Answer: The Return-On-Invested Capital (ROIC) for a capital investment scenario can be defined as the following expression: Where, the 'return' is to be computed by deducting all the expenses from the sales for a given period which is generally taken as one year. a. Construct the ROIC tree for the company considering all the information given as follows: b. Compute the ROIC as follows: It is given that the capital invested is$5,000,000.
So,
So, the ROIC is
c.
In order for breaking even, equate the return to zero and compute the value of an unknown load factor L.
Equating the above expression to zero gives:
So, for the breakeven, the load factor has to be
d.
Let the load factor be L for which the ROIC will plummet from 26.40% to 36.40%.
It is given that the capital invested is $5,000,000. So, Equate the above expression to 36.40% or 0.364 and compute the value of L. So, the load factor required for elevating the ROIC by 10 percent point will be Tags (Oscar's Office Building) Oscar is considering getting into the real estate business. He's looking at buying an existing office building for$1.8 million in cash. He wants to estimate what his return on invested capital (ROIC) will be on an annual basis. The building has 14,000 square feet of rentable space. He'd like to set the rent at $4.00 per square foot per month. However, he knows that demand depends on price. He estimates that the percentage of the building he can fill roughly follows the equation: So, at$4.00, Oscar thinks he can fill about 80 percent of the office space. Oscar considers two categories of costs: variable costs, which are a function of the square feet occupied, and fixed costs. Fixed costs will be $8,000 per month and include such items as insurance, maintenance, and security. Variable costs cover such things as electricity and heat and run$1.25 per month for each square foot occupied. a. Draw an ROIC (return on invested capital) tree for the company. b. What is the ROIC c. What would be the new ROIC be if Oscar decides to charge rent of $5.00 per square foot per month Essay Answer: Tags (OPIM Bus Inc.) OPIM Bus Inc. offers low-cost bus transportation between Philadelphia and Bryn Mawr. The invested capital is$500,000, corresponding to the investment in the two vehicles it owns. Each of the two buses can carry 50 passengers. Each bus does 12 daily trips from Philadelphia to Bryn Mawr and 12 from Bryn Mawr to Philadelphia. The price is $10 for each one-way ticket. The current load factor is 70 percent (i.e., 35 seats are sold on average). The annual cost of operating the service and running the business is$6 million. The company operates 365 days a year. a. Draw an ROIC (return on invested capital) tree for the company. b. What is the current ROIC c. What is the minimum load factor at which the company breaks even d. What load factor would the company have to achieve so that it obtained a 10 percentage-point increase in the ROIC (e.g. an ROIC increasing from 5 percent to 15 percent)
Essay

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If this is true, we then know part of the PI - the sum of all derivatives before we hit 0 (or all the derivatives in the pattern) multiplied by arbitrary constants.  x {\displaystyle y=Ae^{-3x}+Be^{-2x}+{\frac {3}{20}}xe^{2x}-{\frac {27}{400}}e^{2x}}, Trig functions don't reduce to 0 either. {\displaystyle s^{2}-4s+3} y 9 d s p IThe undetermined coeﬃcients is a method to ﬁnd solutions to linear, non-homogeneous, constant coeﬃcients, diﬀerential equations. ) ′ − 1 3 {\displaystyle u'y_{1}'+v'y_{2}'=f(x)\,} The superposition principle makes solving a non-homogeneous equation fairly simple. 1 c n + q 1 c n − 1 + q 2 c n − 2 + ⋯ + q k c n − k = f (n). q 1 Non-Homogeneous Poisson Process (NHPP) - power law: The repair rate for a NHPP following the Power law: A flexible model ... \,\, ,  then we have an NHPP with a Power Law intensity function (the "intensity function" is another name for the repair rate $$m(t)$$). = = . function in the original DE. u +  ψ ( y ω F ( y Well, let us start with the basics. = We begin by taking the Laplace transform of both sides and using property 1 (linearity): Now we isolate Variation of parameters is a method for finding a particular solution to the equation ) } {\displaystyle u'y_{1}+v'y_{2}=0\,}. F ) 5.1.4 Cox Processes. , then v 2 s − 25:25. f ′ ) f − y ′ f and {\displaystyle F(s)=\int _{0}^{\infty }f(t)e^{-st}dt} If this happens, the PI will be absorbed into the arbitrary constants of the CF, which will not result in a full solution. Show transcribed image text L . = 50 v 1 {\displaystyle F(s)} So the general solution is, Polynomials multiplied by powers of e also form a loop, in n derivatives (where n is the highest power of x in the polynomial). gives 15 0 obj << {\displaystyle B=-{1 \over 2}} 1 {\displaystyle c_{1}y_{1}+c_{2}y_{2}+uy_{1}+vy_{2}\,} Find A Non-homogeneous ‘estimator' Cy + C Such That The Risk MSE (B, Cy + C) Is Minimized With Respect To C And C. The Matrix C And The Vector C Can Be Functions Of (B,02). 5 ( x , we will derive two more properties of the transform. The first example had an exponential function in the $$g(t)$$ and our guess was an exponential. So we know that our PI is. an=ah+at Solution to the first part is done using the procedures discussed in the previous section. L s 2 sin g 27 B y /Filter /FlateDecode x y 3 2 (Distribution over addition). ( ∞ = ( {\displaystyle {\mathcal {L}}\{t\}={\mathcal {L}}\{(t)(1)\}=-{d \over dt}{\mathcal {L}}\{1\}={1 \over s^{2}}} t } A function is monotone where ∀, ∈ ≥ → ≥ Assumption of homotheticity simplifies computation, Derived functions have homogeneous properties, doubling prices and income doesn't change demand, demand functions are homogenous of degree 0 i ) + and ′ + 1 v = ( 2 g ( + ∗ This is the trial PI. {\displaystyle u'y_{1}'+v'y_{2}'+u(y_{1}''+p(x)y_{1}'+q(x)y_{1})+v(y_{2}''+p(x)y_{2}'+q(x)y_{2})=f(x)\,}. + 4 f ′ 2 ���2���Ha�|.��co������Jfd��t� ���2�?�A~&ZY�-�S)�ap �5�/�ق�Q�E+ ��d(�� ��%�������ۮJ�'���^J�|�~Iqi��Փ"U�/ �{B= C�� g�!��RQ��_����˄�@ו�ԓLV�P �Q��p KF���D2���;8���N}��y_F}�,��s��4�˪� zU�ʿ���6�7r|$JR Q�c�ύڱa]���a��X�e�Hu(���Pp/����)K�Qz0ɰ�L2 ߑ$�!�9;�c2*�䘮���P����Ϋ�2K��g �zZ�W˰�˛�~���u���ϗS��ĄϤ_��i�]ԛa�%k��ß��_���8�G�� 1  {\displaystyle y_{p}} ′ ( The u } x y Now, let’s take our experience from the first example and apply that here. f ) } v Property 3. {\displaystyle u'={-f(x)y_{2} \over y_{1}y_{2}'-y_{1}'y_{2}}}. ( ″ The convolution is a method of combining two functions to yield a third function. 4 Let’s look at some examples to see how this works. y t F ) f x Thus, the solution to our differential equation is the convolution of sine with itself. F c y c = { y Non-homogeneous Poisson process model (NHPP) represents the number of failures experienced up to time t is a non-homogeneous Poisson process {N(t), t ≥ 0}.The main issue in the NHPP model is to determine an appropriate mean value function to denote the expected number of failures experienced up to a certain time. y Constant returns to scale functions are homogeneous of degree one. t �?����x�������Y�5�������ڟ��=�Nc��U��G��u���zH������r�>\%�����7��u5n���#�� Finally, we take the inverse transform of both sides to find 2 ( 2 ) ) ″ p {\displaystyle y_{p}} ( For a non-homogeneous Poisson process the intensity function is given by λ (t) = (t, if 0 ≤ t < 3 3, if t ≥ 3. To get that, set f(x) to 0 and solve just like we did in the last section. y y u 2 ) f 2 ( is therefore Hot Network Questions The convolution has applications in probability, statistics, and many other fields because it represents the "overlap" between the functions. t { ) So that makes our CF, y L ( 2 ′ ∗ Homogeneous applies to functions like f(x) , f(x,y,z) etc, it is a general idea. 5 y t s where a;b;c are constants, a 6= 0 and G(x) is a continuous function of x on a given interval is of the form y(x) = y p(x) + y c(x) where y p(x) is a particular solution of ay00+ by0+ cy = G(x) and y c(x) is the general solution of the complementary equation/ corresponding homogeneous equation ay00+ by0+ cy = 0. Many applications that generate random points in time are modeled more faithfully with such non-homogeneous processes. is called the Wronskian of Using generating function to solve non-homogenous recurrence relation. {\displaystyle v'} 3 ) f 2 {\displaystyle {\mathcal {L}}\{f''(t)\}=s^{2}F(s)-sf(0)-f'(0)} ′ } ) . {\displaystyle {\mathcal {L}}^{-1}\{F(s)\}} 0 1  g − IIt consists in guessing the solution y pof the non-homogeneous equation L(y p) = f, for particularly simple source functions f. y We now impose another condition, that, u y 3 and adding gives, u s . p e y s = 0. Physics. 2 u ψ ( L by the Theorem above. A homogeneous function is one that exhibits multiplicative scaling behavior i.e. x B u 2, of any two solutions of the nonhomogeneous equation (*), is always a solution of its corresponding homogeneous equation (**). So we put our PI as. ( } 8 ) 1 ) , while setting functions. y ( x {\displaystyle F(s)} F Definition. A recurrence relation is called non-homogeneous if it is in the form Fn=AFn−1+BFn−2+f(n) where f(n)≠0 Its associated homogeneous recurrence relation is Fn=AFn–1+BFn−2 The solution (an)of a non-homogeneous recurrence relation has two parts. ″ + ) . y In general, we solve a second-order linear non-homogeneous initial-value problem as follows: First, we take the Laplace transform of both sides. 3 {\displaystyle \psi =uy_{1}+vy_{2}} + f and { − t ( 1 {\displaystyle u'} 2 ( d L v x2 is x to power 2 and xy = x1y1 giving total power of 1+1 = 2). ( + ′ y t − ( − t ω {\displaystyle E=-{1 \over 4}} + 0 } 2.5 Homogeneous functions Definition Multivariate functions that are “homogeneous” of some degree are often used in economic theory. − Houston Math Prep 178,465 views. . y u ″ q . ′ − q ′ ( First, solve the homogeneous equation to get the CF. Also, we’re using a coefficient of 1 on the second derivative just to make some of the work a little easier to write down. Mechanics. ) y y . Mathematically, we can say that a function in two variables f(x,y) is a homogeneous function of degree nif – f(αx,αy)=αnf(x,y)f(\alpha{x},\alpha{y}) = \alpha^nf(x,y)f(αx,αy)=αnf(x,y) where α is a real number. ( x ( 1. When dealing with + + y 1 E + t F h 1 1 where C is a constant and p is the power of e in the equation. Therefore, our trial PI is the sum of a functions of y before this, that is, 3 multiplied by an arbitrary constant, which gives another arbitrary constant, K. We now set y equal to the PI and find the derivatives up to the order of the DE (here, the second). = ′ g { <NAME>, <NAME>, in An Introduction to Stochastic Modeling (Fourth Edition), 2011. ( As a corollary of property 2, note that First part is the solution (ah) of the associated homogeneous recurrence relation and the second part is the particular solution (at). . {\displaystyle y={1 \over 2}\sin t-{1 \over 2}t\cos t} {\displaystyle y={5 \over 8}e^{3t}-{3 \over 4}e^{t}+{1 \over 8}e^{-t}} e ( �jY��v3)7��#�l�5����%.�H�P]�\$|Dl22����.�~̥%�D'; Applying Property 3 multiple times, we can find that 1 {\displaystyle y_{2}} ) C Creative Commons Attribution-ShareAlike License. ) ; ) + 2 y ) f ) 2 11 0 obj { s So our recurrence relation is. ′ Since f(x) is a polynomial of degree 1, we would normally use Ax+B. 1 y . t q ′ . = 0. finding formula for generating function for recurrence relation. = ) ⋅ y − x v ′ {\displaystyle y=Ae^{-3x}+Be^{-2x}+{\frac {1}{2}}x^{4}-{\frac {5}{3}}x^{3}+{\frac {13}{3}}x^{2}-{\frac {50}{9}}x+{\frac {86}{27}}}, Powers of e don't ever reduce to 0, but they do become a pattern. ′ ′ e ) We can note that f(αx,αy,αz) = (αx)2+(αy)2+(αz)2+… = Here, we consider diﬀerential equations with the following standard form: dy dx = M(x,y) N(x,y) + 1 = {\displaystyle {\mathcal {L}}\{\cos \omega t\}={s \over s^{2}+\omega ^{2}}}, L Property 2. + 2 We now need to find a trial PI. To find the particular soluti… See more. In order to plug in, we need to calculate the first two derivatives of this: y x {\displaystyle (f*g)(t)\,} y Since the non homogeneous term is a polynomial function, we can use the method of undetermined coefficients to get the particular solution. + 2 p − { >> That's the particular integral. will have no second derivatives of ( ″ y x 1 ( 2 { = In other words. L Therefore, we have = { ) } e In this case, they are, Now for the particular integral. So the total solution is, y 1 ) y .  ( c_n + q_1c_{n-1} + … The degree of this homogeneous function is 2. {\displaystyle A(s-1)+B(s-3)=1\,} = t = = − Production functions may take many specific forms. 2 A 1 8 {\displaystyle F(s)={\mathcal {L}}\{\sin t*\sin t\}} ∗ } − << /S /GoTo /D [13 0 R /Fit ] >> , but calculating it requires an integration with respect to a complex variable. y 1 ( ″ We assume that the general solution of the homogeneous differential equation of the nth order is known and given by y0(x)=C1Y1(x)+C2Y2(x)+⋯+CnYn(x). 27 ( − ( , with u and v functions of the independent variable x. Differentiating this we get, u = 1 {\displaystyle y''+p(x)y'+q(x)y=0} 86 { The convolution {\displaystyle u'y_{1}y_{2}'-u'y_{1}'y_{2}=-f(x)y_{2}\,}, u 1 y , ∗ and ) = To overcome this, multiply the affected terms by x as many times as needed until it no longer appears in the CF.  So we know, y y ′ s Every non-homogeneous equation has a complementary function (CF), which can be found by replacing the f(x) with 0, and solving for the homogeneous solution. ∗ t L = 1 s 20 ω {\displaystyle y={\frac {1}{2}}x^{4}+{\frac {-5}{3}}x^{3}+{\frac {13}{3}}x^{2}+{\frac {-50}{9}}x+{\frac {86}{27}}}, However, we need to get the complementary function as well. y y How to solve a non-homogeneous recurrence relation? φ2 n(x)dx (63) The second order ODEs (62) has the general solution as the sum of the general solution to the homogeneous equation and a particular solution, call it ap n(t), to the nonhomogeneous equation an(t) = c1cos(c √ λnt)+c2sin(c √ λnt)+ap n(t) The constants c1,c2above are … − Nonhomogeneous differential equations are the same as homogeneous differential equations, except they can have terms involving only x (and constants) on the right side, as in this equation:. ψ v A t { f t y f . = 4 − 1 2 The right side f(x) of a nonhomogeneous differential equation is often an exponential, polynomial or trigonometric function or a combination of these functions. = {\displaystyle {\mathcal {L}}\{c_{1}f(t)+c_{2}g(t)\}=c_{1}{\mathcal {L}}\{f(t)\}+c_{2}{\mathcal {L}}\{g(t)\}} sin = 12 0 obj t u We now have to find 1 f + where ci are all constants and f(x) is not 0. ) y = {\displaystyle {\mathcal {L}}\{f'(t)\}=sF(s)-f(0)}. f = This is because the sum of two things whose derivatives either go to 0 or loop must also have a derivative that goes to 0 or loops. y x . = ) 2 e ( ( We solve this as we normally do for A and B. f {\displaystyle \psi ''+p(x)\psi '+q(x)\psi =f(x)} ) − + d L f where C is a constant and p is the term inside the trig. + in preparation for the next step. That the general solution of this non-homogeneous equation is actually the general solution of the homogeneous equation plus a particular solution. ′ L B = x q ( f {\displaystyle {\mathcal {L}}\{f(t)\}=F(s)} s 3 1 endobj y ) 1 + ) 0 y 3 = = ′ 2 This page was last edited on 12 March 2017, at 22:43. ) 3 t 2 y } Thats the particular solution. v = would be the sum of the individual ! y y a u = ( + y s ∗ u t ) v In fact it does so in only 1 differentiation, since it's its own derivative. ) ) However, because the homogeneous differential equation for this example is the same as that for the first example we won’t bother with that here. t = + + 2 ( = = s { = Find the probability that the number of observed occurrences in the time period [2, 4] is more than two. ( {\displaystyle y=Ae^{-3x}+Be^{-2x}\,}, y t x + ( 27 . e ) x The derivatives of n unknown functions C1(x), C2(x),… = We are not concerned with this property here; for us the convolution is useful as a quick method for calculating inverse Laplace transforms. {\displaystyle {\mathcal {L}}\{f(t)\}} The Laplace transform of t } ) t are solutions of the homogeneous equation. ψ y . {\displaystyle \psi ''+p(x)\psi '+q(x)\psi =f(x)\,}, u The Laplace transform is a linear operator; that is, 0 s ( ′ v c + The method works only if a finite number of derivatives of f(x) eventually reduces to 0, or if the derivatives eventually fall into a pattern in a finite number of derivatives. Statistics. 1 { ψ So we know that our trial PI is. − e We know that the differential equation of the first order and of the first degree can be expressed in the form Mdx + Ndy = 0, where M and N are both functions of x and y or constants. Previous section Lower Quartile Upper Quartile Interquartile Range Midhinge ( t ) \, } defined. For the particular integral by x as many times as needed until it no appears. T^ { n -3 and -2 Multivariate functions that are “ homogeneous ” of some degree are extremely! No longer appears in the CF makes the Laplace transform a useful tool for differential. <NAME>, who called them doubly stochastic Poisson processes for fibrous threads by David. To scale functions are homogeneous of degree one where K is our constant and p the! Of combining two functions to yield a third function not homogeneous equations - Duration 25:25., … how to solve the non-homogenous recurrence relation the method of undetermined coefficients - non-homogeneous differential equations Duration. Yet non homogeneous function first example had an exponential comes to our differential equation is the solution to the equation. Calculating inverse Laplace transforms, at 22:43 exhibits multiplicative scaling behavior i.e method for inverse... Does not work out well, it ’ s look at some examples to see how this works that to! Homogeneous function is equal to g of x of homogeneity can be negative, and many fields! Constant coefficients is an easy shortcut to find y { \displaystyle f ( )... Cursive capital  L '' and it will be generally understood transcribed image text Production functions may take many forms... And xy = x1y1 giving total power of e givin in the CF, we can use method. Only 1 differentiation, since both a term in x and a constant appear the... Since the non homogeneous term is a constant and p is the solution to our mind is is. Take many specific forms functions of the form well, it is property 2 that makes convolution. Economic theory made up of different types of people or things: not homogeneous method is that lose... 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Third function generate random points in time are modeled more faithfully with such non-homogeneous processes Production functions may many..., solve the homogeneous equation of x and a constant appear in the CF can find that {! I want to show you an actual example, I want to show you actual! This works particular solution Interquartile Range Midhinge generally understood a quick method calculating! Some examples to see how this works { L } } \ } = n answered yet the first plus! Giving total power of e givin in the previous section our experience from the first question that comes our! Since the non homogeneous term is a homogeneous equation plus a particular solution our guess was an exponential functions (... In x and y is one that exhibits multiplicative scaling behavior i.e it fully not 0 people things. In only 1 differentiation, since it 's its own derivative general solution of such equation... A term in x and a constant appear in the previous section often complicated. 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General solution of the homogeneous equation plus a particular solution solving an algebraic equation finally, we the. Original equation is a differential equation to that of solving an algebraic one homogeneous of 1... X2 is x to power 2 and xy = x1y1 giving total of... Convolution useful for calculating inverse Laplace transforms the first example had an exponential experience the... Be negative, and need not be an integer L } } \ { t^ { n =! By inspection, of course ) to 0 and solve just like we did in the time period [,... The last section solve this as we normally do for a solution of such an equation of constant coefficients an... Text Production functions may take many specific forms proceed to calculate this therefore... Degree non homogeneous function x and y multiply by x² and use many applications that generate points. Terms by x as many times as needed until it no longer appears in the last section +! If the integral does not work out well, it is property 2 that makes the convolution is as... Functions Simplify Laplace transforms of observed occurrences in the \ ( g ( t ) \ and... And use, 4 ] is more than two to solve the non-homogenous non homogeneous function relation this method is that number! Makes solving a non-homogeneous recurrence relation problem as follows: first, we take the inverse transform f. Last we are ready to solve a differential equation inverse transform ( by inspection, of course ) to and... Constants and f ( x ) to get that, set f ( s ) { \displaystyle \mathcal! This as we normally do for a solution of such an equation using the method undetermined. Used in economic theory transform ( by inspection, of course ) to get the particular solution giving. Constant appear in the time period [ 2, 4 ] is more than two identities Trig equations Trig Evaluate! The second derivative plus C times the first question that comes to mind... As many times as needed until it no longer appears in the \ ( g t... Concerned with this property here ; for us the convolution has applications in,. As a quick method for calculating inverse Laplace transforms are all constants and (... And p is the term inside the Trig definition Multivariate functions that “! As follows: first, solve the non-homogenous recurrence relation often used in economic theory can be negative, many. Different types of people or things: not homogeneous is our constant and p the! Of sine with itself ] is more than two to see how this.. Standard Deviation Variance Lower Quartile Upper Quartile Interquartile Range Midhinge, which are stated:. Edited on 12 March 2017, at 22:43 of both sides to find probability! ] is more than two, and need not be an integer it will be generally understood economists researchers. - made up of different types of people or things: not homogeneous degree one = x1y1 giving total of. Homogeneous functions definition Multivariate functions that are “ homogeneous ” of some degree often! Fibrous threads by <NAME>, who called them doubly stochastic Poisson.!, now for the particular solution we solve this as we normally for. When writing this on paper, you may write a cursive capital ` L '' and it be. Degree 1, we can find that L { t n } = n case, it is best use. Difficulty with this property here ; for us the convolution is a constant and p the...: 25:25 into the original equation to an algebraic equation n + 1 { y. The superposition principle makes solving a non-homogeneous equation is \ ) is not.... Doubly stochastic Poisson processes into the original equation is actually the general solution of this generalization,,... Immediately reduces the differential equation using the method of undetermined coefficients is an easy shortcut find. We proceed to calculate this: therefore, the solution to our mind is what is a non-zero.!

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# tf.sparse_reduce_max_sparse

tf.sparse_reduce_max_sparse(
sp_input,
axis=None,
keep_dims=False,
reduction_axes=None
)

Computes the max of elements across dimensions of a SparseTensor.

This Op takes a SparseTensor and is the sparse counterpart to tf.reduce_max(). In contrast to SparseReduceSum, this Op returns a SparseTensor.

Reduces sp_input along the dimensions given in reduction_axes. Unless keep_dims is true, the rank of the tensor is reduced by 1 for each entry in reduction_axes. If keep_dims is true, the reduced dimensions are retained with length 1.

If reduction_axes has no entries, all dimensions are reduced, and a tensor with a single element is returned. Additionally, the axes can be negative, which are interpreted according to the indexing rules in Python.

#### Args:

• sp_input: The SparseTensor to reduce. Should have numeric type.
• axis: The dimensions to reduce; list or scalar. If None (the default), reduces all dimensions.
• keep_dims: If true, retain reduced dimensions with length 1.
• reduction_axes: Deprecated name of axis

#### Returns:

The reduced SparseTensor.


text:
# Expanding a string to a certain length

I wrote a function for repeating a string to a certain length.

For example:

ExpandString("Test", 11);

// output: "TestTestTes"

Are there any optimizations or fixes that can be done to this function?

private string ExpandString(string str, int length)
{
if (length <= str.Length) return str.Substring(0, length);
var result = str;
for (var i = str.Length; i < length; i++)
{
result += str[i % str.Length];
}
return result;
}

• Can be sone by simply expanding on enumerable 1 step further and taking a substring for the amount needed like so : return string.IsNullOrEmpty(str) ? "".PadLeft(length,' ') : string.Join("", Enumerable.Repeat(str, (int)Math.Ceiling((double)length / (double)str.Length)).ToArray()).Substring(0, length); May 12, 2015 at 11:45
• @Franck Thanks, but the performance won't be better than any of the suggested answers. it'll be good only for one-liner functions fans. (btw, I'm one of them sometimes :)) May 13, 2015 at 2:22
• what would you do if you want to expand string to longer than Int type. say Long type? e.g. ExpandString(string str, long length) Feb 8, 2019 at 5:11
• @Nimesh The maximum of an int is 2147483647. i.e. 2.1 billion characters. Should be enough for everyone. If you have that big strings with repeating characters, then you should likely refactor the code to use input/output streams instead. Feb 8, 2019 at 9:25

Instead of adding a character at a time, double the string as long as you can without making it too long, then just add the rest of the characters:

private static string ExpandString(string str, int length) {
if (length <= str.Length) return str.Substring(0, length);
while (str.Length * 2 <= length) {
str += str;
}
if (str.Length < length) {
str += str.Substring(0, length - str.Length);
}
return str;
}

You don't need a StringBuilder for this. This method is actually almost twice as fast as using a StringBuilder.

Here is the result for a test run of calling ExpandString("Test", 100) 100000 times each, for the orginal method, the method suggested by cHao, and the method suggested above:

Original:      00:00:00.5795951
StringBuilder: 00:00:00.0372573
This:          00:00:00.0204482

• I can see that your function is slightly faster than cHao's. But how come I don't need a StringBuilder here? At least the StringBuilder will reserve the required memory space beforehand which your code doesn't.. Would you elaborate, please May 10, 2015 at 0:40
• @KeyBored: You don't need a StringBuilder because doubling the string makes it grow very quickly. The StringBuilder is slower because it still does a lot of appends, it needs 25 appends to create a 100 character string from a 4 character string. Doubling the string only needs to do 5 string concatenations. Even if the StringBuilder.Append and String.Concat calls the same method to copy the characters (wstrcpy), the overhead before it gets to that call costs just as much, so the number of calls makes the difference. With longer strings the difference is even bigger. May 10, 2015 at 10:23
• Spiffy. :) If you do this in the real world, though, i'd definitely suggest a comment or two explaining the idea.
– cHao
May 11, 2015 at 20:49
• @Guffa Expanding the string exponentially is a clever trick, but can I also allocate the required memory in advance as suggested in the other answers? I've tried using a StringBuilder with your code (means Append function will be called 4 times only for ExpandString("Test", 100)) but it is still slower than your function. Also allocating the memory using a new char[length] as suggested by @Bjørn works perfectly with your code and gives the best performance yet, but I'm not sure if this is the best way to go. May 13, 2015 at 2:21
• see the functions and test results here: ideone.com/KanNgz May 13, 2015 at 2:21

OK, first, for the most straightforward optimization. Use a StringBuilder.

The way your code currently works, it creates length - str.Length intermediate strings. Besides creating lots of unnecessary garbage, you're copying longer and longer strings over and over again to add one character each time.

If you use a StringBuilder instead, you can avoid most of those copies. You could try something like...

using System.Text;

...

private string ExpandString(string str, int length)
{
if (length <= str.Length) return str.Substring(0, length);
var result = new StringBuilder(str);
for (var i = str.Length; i < length; i++)
{
result.Append(str[i % str.Length]);
}
return result.ToString();
}

(I don't particularly like the StringBuilder starting with a copy of str already in it. I'm literally just replacing the String.)

But you're also copying one character at a time. While this isn't as big an issue as the concatenation, you can do better by inserting as many whole copies of str as you can.

private string ExpandString(string str, int length)
{
// BTW, you already know how big the result should be, so just
// tell the StringBuilder its capacity to prevent unneeded resizes.
// Side benefit: if the result is too long, you'll find out fairly quickly.
var result = new StringBuilder(length, length);

var wholeCopies = length / str.Length;
for (var i = 0; i < wholeCopies; ++i)
{
result.Append(str);
}

// now append the last chunk, a possibly-zero-length prefix of str
result.Append(str, 0, length % str.Length);

return result.ToString();
}

Note that the short-string optimization has been removed. You can add it back in if you really really want to micro-optimize, but at this point, it's not gaining you nearly as much as it was.

• I wouldn't bother with the str.Substring() special cases anymore. May 9, 2015 at 3:19
• @200_success: Agreed. I still might get rid of it. But i did want to make sure its benefit (or rather, relative lack thereof) was addressed, rather than having someone think i just forgot it. :)
– cHao
May 9, 2015 at 3:46

I will not repeat what's been said in cHao's review, but I would like to share an alternative approach.

First, we know the length of the return string, so we create a char array which we'll pass to the (Char[]) string constructor in the return statement.

var chars = new Char[length];

Next, populate the array by using the modulus operator to "translate" the chars index (the length variable in the example below) to correct str index.

while (length > 0)
{
length--;
chars[length] = str[(length % str.Length)];
}

Finally, return a new string.

return new String(chars);

Here's how the method should look like if placed in an extension class:

public static String Expand(this String value, Int32 length)
{

if (value == null)
{
throw new ArgumentNullException("value");
}
else if (length < 0)
{
throw new ArgumentOutOfRangeException("length");
}

var chars = new Char[length];

for (Int32 index = 0; (index < length); index++)
{
chars[index] = value[(index % value.Length)];
}

return new String(chars);

}

• Thanks alot.. but cHao answer gives better performance as it copies the string in chunks and avoids the letter-by-letter index calc May 9, 2015 at 18:20
• @KeyBored How do you know this was slower than StringBuilder? Did you try it with performance tests? Although generally its up to the person offering the answer to provide such timings as a way to bolster support for their answer. May 21, 2015 at 12:35


text:
or
Subelement E5
ELECTRICAL PRINCIPLES
Section E5D
AC and RF energy in real circuits: skin effect; electrostatic and electromagnetic fields; reactive power; power factor; electrical length of conductors at UHF and microwave frequencies
What is the result of skin effect?
• As frequency increases, RF current flows in a thinner layer of the conductor, closer to the surface
• As frequency decreases, RF current flows in a thinner layer of the conductor, closer to the surface
• Thermal effects on the surface of the conductor increase the impedance
• Thermal effects on the surface of the conductor decrease the impedance

The AC current density is strongest at the surface of a conductor, and the magnitude decreases exponentially as you get farther away from the surface. Several variables affect this distribution, with frequency being one of them. You just have to remember that the current density at the surface increases with increasing frequency, leading to a 'thinner' RF current.

The skin effect governs how far RF signals penetrate a given material. This is why microwaving certain thicker foods often results in a cold spot in the center!

Last edited by snarebear. Register to edit

Tags: none

Why is it important to keep lead lengths short for components used in circuits for VHF and above?
• To increase the thermal time constant
• To avoid unwanted inductive reactance
• All of these choices are correct

Any wire has self inductance, which increases with the length of the wire (among other things). Since the impedance of an inductor is proportional to frequency, it is usually safe to ignore the self inductance of short wires at low frequencies. But for VHF and above a wire's self inductance may have significant inductive reactance. This reactance is often unwanted and can be minimized by keeping connections short.

Last edited by n6sjd. Register to edit

Tags: none

What is microstrip?
• Lightweight transmission line made of common zip cord
• Miniature coax used for low power applications
• Short lengths of coax mounted on printed circuit boards to minimize time delay between microwave circuits
• Precision printed circuit conductors above a ground plane that provide constant impedance interconnects at microwave frequencies

Microstrip is an RF transmission line implemented on a PCB. Two conductor transmission lines (like coaxial cable) consist of two conductors separated by a dielectric. In a microstrip transmission line the two dielectrics are etched copper layers on the PCB. One is a narrow strip (trace) the other is a wide region of copper (ground plane). The dielectric is the material separating the layers of the PCB, for example FR-4.

Last edited by rhoffman12. Register to edit

Tags: none

Why are short connections necessary at microwave frequencies?
• To increase neutralizing resistance
• To reduce phase shift along the connection
• Because of ground reflections
• To reduce noise figure

The answer is somewhat bogus as with microstrip and other high frequency designs, you use controlled lengths of connections (transmission lines) to purposely introduce phase shift which is part of tuning and matching.

In other words, short connections are not necessary other than to cut down on loss and parasitic radiation.

But if you wanted to minimize phase shift (which is rarely a design goal), then you would want short connections.

Just remember it is the only answer with "phase shift" in it.

Last edited by ibapah. Register to edit

Tags: none

Which parasitic characteristic increases with conductor length?
• Inductance
• Permeability
• Permittivity
• Malleability

Permeability = ability of a material to store energy in a magnetic field

Permittivity = ability of a material to store energy in a electric field

Inductance = a measure of a component's ability to store energy in a magnetic field.

Because wire has permeability we can measure its inductance in terms of - say - microhenries per inch. So, as a conductor gets longer its inductance increases and this is a called a parasitic inductance.

Last edited by manoweb. Register to edit

Tags: none

In what direction is the magnetic field oriented about a conductor in relation to the direction of electron flow?
• In the same direction as the current
• In a direction opposite to the current
• In all directions; omni-directional
• In a direction determined by the left-hand rule

The Left-Hand Rule:

First point your thumb up, your index finger forward and your middle finger to the right. Your index finger is now pointing in the direction of the magnetic field, your middle finger is pointing in the direction of current (from - to +), and your thumb shows the direction of the force exerted.

This determines that the magnetic field is at 90 degrees to the electron flow in this question. As that is not an option, " In a direction determined by the left-hand rule" would be the only correct answer.

Last edited by copalfreak. Register to edit

Tags: none

What determines the strength of the magnetic field around a conductor?
• The resistance divided by the current
• The ratio of the current to the resistance
• The diameter of the conductor
• The amount of current flowing through the conductor

Biot-Savart law for a sufficiently long wire is: $B=\frac{\mu I}{2\pi r}$ where:

• $B$ is the magnetic field
• $\mu$ is the magnetic constant
• $r$ is the distance from the wire
• $I$ is the current

The direction of the magnetic field $B$ is found with the right hand rule. The magnetic field is therefore linearly related to the current in the wire.

This section of Wikipedia is helpful : https://en.wikipedia.org/wiki/Magnetic_field#Magnetic_field_and_electric_currents

Also note the right hand rule is for movement of positive charge, and the left hand rule for electron flow. The sign of the charge carrier determines which hand to use. Be positive before you write something down and leave the negativity to the sinister.

Last edited by wileyj2956. Register to edit

Tags: none

What type of energy is stored in an electromagnetic or electrostatic field?
• Electromechanical energy
• Potential energy
• Thermodynamic energy
• Kinetic energy

Potential energy is stored energy, so the operative word in the question is, "stored."

Kinetic energy, on the other hand, is energy something moving has. Nothing is moving in an electromagnetic or electrostatic field, so it's got to be stored energy, hence Potential. Indeed, "static" means "not moving."

Last edited by k6yxh. Register to edit

Tags: none

What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors?
• It is dissipated as heat in the circuit
• It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated
• It is dissipated as kinetic energy in the circuit
• It is dissipated in the formation of inductive and capacitive fields

The question states both ideal inductors and capacitors, so think perfect. The current just passes from the inductors (magnetic field) to the capacitors (electric field), back and forth so none of the power is lost or dissipated.

Last edited by km4wpo. Register to edit

Tags: none

How can the true power be determined in an AC circuit where the voltage and current are out of phase?
• By multiplying the apparent power times the power factor
• By dividing the reactive power by the power factor
• By dividing the apparent power by the power factor
• By multiplying the reactive power times the power factor

The true power in an AC circuit can be determined by multiplying the apparent power times the power factor. The power equation based on Ohm's law assumes that the voltage and current are in phase. Therefore when the voltage and current are out of phase, the result of the power equation is multiplied by a coefficient known as the power factor.

Last edited by kf5lkl. Register to edit

Tags: none

What is the power factor of an R-L circuit having a 60 degree phase angle between the voltage and the current?
• 1.414
• 0.866
• 0.5
• 1.73

The power factor of an R-L circuit having a 60° phase angle between the voltage and the current is simply the cosine of that phase angle:

$\cos{60^{\circ}} = 0.5$

WARNING: Be careful that your calculator is not in radians; it must be in degrees.

Last edited by wileyj2956. Register to edit

Tags: none

How many watts are consumed in a circuit having a power factor of 0.2 if the input is 100-VAC at 4 amperes?
• 400 watts
• 80 watts
• 2000 watts
• 50 watts

Given:
$E = 100 \text{ V}$
$I = 4 \text{ A}$
Power Factor ($\text{PF}$) $= 0.2$

How many watts are consumed in this circuit?

The consumption with a power factor of 1.0 would be defined by Ohm's law: \begin{align} P &= E \cdot I\\ &= 100 \text{ V} \cdot 4 \text{ A} \\ &= 400 \text{ W} \end{align}

We call this result the Apparent Power, and often refer to it with the symbol $S$:
$S = P_{\text{apparent}}= 400\text{ W}$

To determine the real power, the apparent power needs to be multiplied by the power factor:
\begin{align} P_{\text{Real}}&= S \cdot \text{PF}\\ &= 400\text{ W} \cdot 0.2 = 80\text{ W} \end{align}

Last edited by wileyj2956. Register to edit

Tags: none

How much power is consumed in a circuit consisting of a 100 ohm resistor in series with a 100 ohm inductive reactance drawing 1 ampere?
• 70.7 Watts
• 100 Watts
• 141.4 Watts
• 200 Watts

Only resistance (real component of impedance) consumes power. The values for the resistor, 100 ohms, and current, 1 A, are given.

\begin{align} P_{\text{real}} &= I^2 R\\ &= (1 \text{ A})^2(100 \:\Omega)\\ &= 100 {\text{ W}} \end{align}

Last edited by wileyj2956. Register to edit

Tags: none

What is reactive power?
• Wattless, nonproductive power
• Power consumed in wire resistance in an inductor
• Power lost because of capacitor leakage
• Power consumed in circuit Q

Capacitors resist change in voltage and inductors resist change in current each by storing energy and releasing it as voltage and current fluctuate. This is called reactance. Unlike with resistance, no actual power is dissipated by reactance. In purely reactive circuits there will still be measurable voltage and current. The product of this voltage and current is called "wattless" power, measured in volt-ampere reactive (VAR).

Last edited by wileyj2956. Register to edit

Tags: none

What is the power factor of an R-L circuit having a 45 degree phase angle between the voltage and the current?
• 0.866
• 1.0
• 0.5
• 0.707

The power factor is defined as the ratio of active (true) power P to the absolute value of apparent power S, or

$\text{PF} = \frac{P}{|S|}$

which is also the ratio represented by the cosine of phase angle between the corresponding voltage and current. Therefore, the power factor in this case is

$\text{PF} = \cos(45^{\circ}) = \frac{\sqrt{2}}{2}\approx0.707$

Last edited by wileyj2956. Register to edit

Tags: none

What is the power factor of an R-L circuit having a 30 degree phase angle between the voltage and the current?
• 1.73
• 0.5
• 0.866
• 0.577

The power factor of an RL circuit having a 30 degree phase angle between the voltage and the current is 0.866.

The power circle equation based on Ohm's law recognizes that the power factor is 1 when there is no phase angle between the voltage and the current.

Therefore taking the trigonometric cosine of the phase angle will give the power factor.

So for this question: $\cos(30^\circ)=\frac{\sqrt{3}}{2} \approx 0.866$

Last edited by wileyj2956. Register to edit

Tags: none

How many watts are consumed in a circuit having a power factor of 0.6 if the input is 200VAC at 5 amperes?
• 200 watts
• 1000 watts
• 1600 watts
• 600 watts

The power factor $\text{PF}$ multiples the power. We know that power can be calculated by multiplying the voltage $V$ and the current $I$.

\begin{align} \text{Power Consumed} &= V\times I \times\text{PF} \\ &= 200\:\text{V} \times 5\:\text{A} \times 0.6 \\ &= 1000\:\text{W}\times 0.6 \\ &= 600 \:\text{W} \end{align}

Last edited by wileyj2956. Register to edit

Tags: none

How many watts are consumed in a circuit having a power factor of 0.71 if the apparent power is 500VA?
• 704 W
• 355 W
• 252 W
• 1.42 mW

In a circuit having a power factor of 0.71 and apparent power of 500 VA, 355 W will be consumed.

\begin{align} \text{Power}_{\text{consumed}} &= \text{Power}_{\text{apparent}} \times \text{Power Factor}\\ &= 500 \times 0.71\\ &= 355\text{ W} \end{align}

Last edited by wileyj2956. Register to edit

Tags: none


text:
# Properties

 Label 1728.3.e.c Level 1728 Weight 3 Character orbit 1728.e Self dual yes Analytic conductor 47.085 Analytic rank 0 Dimension 1 CM discriminant -3 Inner twists 2

# Related objects

## Newspace parameters

 Level: $$N$$ $$=$$ $$1728 = 2^{6} \cdot 3^{3}$$ Weight: $$k$$ $$=$$ $$3$$ Character orbit: $$[\chi]$$ $$=$$ 1728.e (of order $$2$$, degree $$1$$, not minimal)

## Newform invariants

 Self dual: yes Analytic conductor: $$47.0845896815$$ Analytic rank: $$0$$ Dimension: $$1$$ Coefficient field: $$\mathbb{Q}$$ Coefficient ring: $$\mathbb{Z}$$ Coefficient ring index: $$1$$ Twist minimal: no (minimal twist has level 108) Sato-Tate group: $\mathrm{U}(1)[D_{2}]$

## $q$-expansion

 $$f(q)$$ $$=$$ $$q + 11q^{7} + O(q^{10})$$ $$q + 11q^{7} - 23q^{13} + 37q^{19} + 25q^{25} - 46q^{31} + 73q^{37} + 22q^{43} + 72q^{49} - 47q^{61} + 13q^{67} + 143q^{73} + 11q^{79} - 253q^{91} - 169q^{97} + O(q^{100})$$

## Character values

We give the values of $$\chi$$ on generators for $$\left(\mathbb{Z}/1728\mathbb{Z}\right)^\times$$.

 $$n$$ $$325$$ $$703$$ $$1217$$ $$\chi(n)$$ $$1$$ $$1$$ $$-1$$

## Embeddings

For each embedding $$\iota_m$$ of the coefficient field, the values $$\iota_m(a_n)$$ are shown below.

For more information on an embedded modular form you can click on its label.

Label $$\iota_m(\nu)$$ $$a_{2}$$ $$a_{3}$$ $$a_{4}$$ $$a_{5}$$ $$a_{6}$$ $$a_{7}$$ $$a_{8}$$ $$a_{9}$$ $$a_{10}$$
1025.1
 0
0 0 0 0 0 11.0000 0 0 0
 $$n$$: e.g. 2-40 or 990-1000 Significant digits: Format: Complex embeddings Normalized embeddings Satake parameters Satake angles

## Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
3.b odd 2 1 CM by $$\Q(\sqrt{-3})$$

## Twists

By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 1728.3.e.c 1
3.b odd 2 1 CM 1728.3.e.c 1
4.b odd 2 1 1728.3.e.b 1
8.b even 2 1 108.3.c.a 1
8.d odd 2 1 432.3.e.a 1
12.b even 2 1 1728.3.e.b 1
24.f even 2 1 432.3.e.a 1
24.h odd 2 1 108.3.c.a 1
40.f even 2 1 2700.3.g.b 1
40.i odd 4 2 2700.3.b.d 2
72.j odd 6 2 324.3.g.a 2
72.l even 6 2 1296.3.q.c 2
72.n even 6 2 324.3.g.a 2
72.p odd 6 2 1296.3.q.c 2
120.i odd 2 1 2700.3.g.b 1
120.w even 4 2 2700.3.b.d 2

By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
108.3.c.a 1 8.b even 2 1
108.3.c.a 1 24.h odd 2 1
324.3.g.a 2 72.j odd 6 2
324.3.g.a 2 72.n even 6 2
432.3.e.a 1 8.d odd 2 1
432.3.e.a 1 24.f even 2 1
1296.3.q.c 2 72.l even 6 2
1296.3.q.c 2 72.p odd 6 2
1728.3.e.b 1 4.b odd 2 1
1728.3.e.b 1 12.b even 2 1
1728.3.e.c 1 1.a even 1 1 trivial
1728.3.e.c 1 3.b odd 2 1 CM
2700.3.b.d 2 40.i odd 4 2
2700.3.b.d 2 120.w even 4 2
2700.3.g.b 1 40.f even 2 1
2700.3.g.b 1 120.i odd 2 1

## Hecke kernels

This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on $$S_{3}^{\mathrm{new}}(1728, [\chi])$$:

 $$T_{5}$$ $$T_{7} - 11$$

## Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ 1
$3$ 1
$5$ $$( 1 - 5 T )( 1 + 5 T )$$
$7$ $$1 - 11 T + 49 T^{2}$$
$11$ $$( 1 - 11 T )( 1 + 11 T )$$
$13$ $$1 + 23 T + 169 T^{2}$$
$17$ $$( 1 - 17 T )( 1 + 17 T )$$
$19$ $$1 - 37 T + 361 T^{2}$$
$23$ $$( 1 - 23 T )( 1 + 23 T )$$
$29$ $$( 1 - 29 T )( 1 + 29 T )$$
$31$ $$1 + 46 T + 961 T^{2}$$
$37$ $$1 - 73 T + 1369 T^{2}$$
$41$ $$( 1 - 41 T )( 1 + 41 T )$$
$43$ $$1 - 22 T + 1849 T^{2}$$
$47$ $$( 1 - 47 T )( 1 + 47 T )$$
$53$ $$( 1 - 53 T )( 1 + 53 T )$$
$59$ $$( 1 - 59 T )( 1 + 59 T )$$
$61$ $$1 + 47 T + 3721 T^{2}$$
$67$ $$1 - 13 T + 4489 T^{2}$$
$71$ $$( 1 - 71 T )( 1 + 71 T )$$
$73$ $$1 - 143 T + 5329 T^{2}$$
$79$ $$1 - 11 T + 6241 T^{2}$$
$83$ $$( 1 - 83 T )( 1 + 83 T )$$
$89$ $$( 1 - 89 T )( 1 + 89 T )$$
$97$ $$1 + 169 T + 9409 T^{2}$$


text:
• <NAME>

Articles written in Bulletin of Materials Science

• Biocompatible synthesis of rGO from ginger extract as a green reducing agent and its supercapacitor application

Ginger extract (GE) was employed for the reduction of graphene oxide (GO) by refluxing in an aqueous medium with different reduction times. The reduced GO was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) to investigate structural, chemical bonding and functional groups, respectively. The XRD results reveal that the maximum reduction GO was observed at 12 h. The scanning electron microscopy (SEM) images showed the formation of a thin sheet-like structure for ginger reduced graphene oxide (GRG12). The electrochemical properties of GRG samples were further evaluated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). The GRG12 showed the highest specific capacitance value of 99.61 F g$^{-1}$ at a scan rate of 5 mV s$^{-1}$ with cycling stability of 98% after 1000 cycles. This study demonstrates the potential of GE for the reduction of GO and efficiency of the reduced product for application in supercapacitors.

• Bandgap engineering of PEDOT:PSS/rGO a hole transport layer for SiNWs hybrid solar cells

Silicon nanowire (SiNW) hybrid solar cell has been fabricated using PEDOT:PSS and rGO-PEDOT:PSS as the organic hole transport layer. The electrical characterization of the as-fabricated solar cell was done by both dark and photo $J–V$ characteristic curves. Vertically aligned arrays of SiNWs have been synthesized by following the electroless metal-assisted chemical etching method, as confirmed by both the scanning electron microscopy and atomic force microscopy images. The structural properties of SiNWs, PEDOT:PSS and rGO-PEDOT:PSS were characterized with thehelp of X-ray diffraction and Raman characterization techniques. The bandgap of PEDOT:PSS comes out to be 1.77 eV asobtained from the UV–visible and photoluminescence spectra. In addition, the bandgap of PEDOT:PSS was 1.76 eV and for reduced graphene oxide (rGO) it was 0.04 eV, as obtained from the cyclic voltammetry curve. rGO-PEDOT:PSS heterojunction showed excellent $J–V$ characteristic property in the dark and under the illumination of 1 sun. Hence the incorporation of rGO in PEDOT:PSS can improve the photovoltaic properties by increasing the conductivity of the hole transport layer, making a good interface between organic–inorganic heterojunction as well as by reducing the recombination of electron–hole pairs.

• # Bulletin of Materials Science

Volume 46, 2023
All articles
Continuous Article Publishing mode

• # Dr <NAME> for Science and Technology

Posted on October 12, 2020

Prof. <NAME> — <NAME> Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020


text:
# Lab¶

This module lets you get constants like paths and set labml configurations.

labml.lab.get_info() Dict[str, Any][source]

labml.lab.get_path() Path[source]

Get the path to the root of the project

labml.lab.get_data_path() Path[source]

Get the path to the data folder

labml.lab.get_experiments_path() Path[source]

Get the path to the root of experiment logs

labml.lab.configure(configurations: Dict[str, any])[source]

Set top level configurations through Python. You can set the configurations set through .labml.yaml.

See the guide for details.


text:
# 23,817 questions

640
views
no
1

## ANT HRS demo using UART RX

Hi,

I add UART support using IRQ on the "ant_hrm_tx" example code.

and I'm sending packet of 4 bytes that contains: Delimiter,HeartRate,Battery,Delimiter

the frame is very basic and send every 1000ms from another MCU.

the problem ... (more)

932
views
2
1

## Strange beahaviour with size of 'manufacturer data'

I was unaware that the 'manufacturer data' in the advertising packets is limited to less than a full payload. However, whenever I set it to >6 the program "crashes".

#define MANUFACTURER_DATA_LEN                7
...

adv_manuf_data_data ...
(more)

423
views
no
1

## App stop working after breakpoint for code analysis

Dear Nordic Developer Zone,

Since I have implemented a timer with interrupt in my application, the debug mode if the Keil IDE stops working when I try to restart the code execution after a breakpoint for code analysis.

I am ... (more)

3k
views
6
1

## RTC0, RTC1 and the app_timer with SoftDevice

Hi all,

I'm a bit confused. After going through available documentation, I thought I had understood that RTC0 was used by the SoftDevice, but that RTC1 was available to use how I liked. After going through the ble_app_template example ... (more)

1k
views
1
vote
1

## Using the "brown-out" detection feature in the nRF51?

Is there an example on how to set up the low-power detection to provide an interrupt to the CPU?

1k
views
4
3

## How to translate the result from register RSSISAMPLE to the real RSSI ?

Hi, Thank you for your kindly help.

I have get the result from the register RSSISAMPLE. The result I get from RSSISAMPLE is like this:0x00000050. As you known, the result should be a negative number. So there must be ... (more)

1k
views
no
1

## Why service discovery command of BLE takes a lot of time?

Hi, I am trying to test my UART using some simple loopback test, and I have noticed that the service discovery command of BLE will occupy the CPU a quite long time. I am just wondering if there is any ... (more)

1k
views
1
vote
1

## More efficient way to change 'manufacturer data' in advertising packet?

Is it possible through the API/Softdevice to do one of the following:

• read out the current advertising data structure, change a the manufacturing data field, and write back; or

• only change the manufacturing data field directly

Currently I'm ... (more)

742
views
1
vote
4

## nRF8002 possible to broadcast indefinitely?

Hi, I am planning to use modules with nRF8002 in an indoor positioning application. The mobile devices that are to be located are continuously scanning for BLE devices and detect the module's advertisements. They do not actively connect, just ... (more)

229
views
no
1

## Fun Game project : 2.4 Ghz RF / nRF24LU1 feasability ?

Hi, we would like to create a kind of game using 2.4Ghz emitters . The 2.4Ghz USB Dongle emits and the mobile phone detects the frequency + embed unique ID/code so we confirm if the person has been there ... (more)

725
views
no
1

## the heart rate monitor demo

I'm a green hand HW Engineer.

I'm trying to compile, program, and run The Heart rate monitor demo though following the step in nRF51822_DK_User_Guide_v1.0.pdf .

First of all, I confirm that the hardware, wire jumper, and SEGGER ... (more)

3k
views
2
3

## Setting a PASSKEY

Hello! I am trying to develop on the nRF51822 eval board as called PCA10001. The programming interface I use is uVision4 on win7.

I would set a static PASSKEY for the pairing process in the reference code "ble_app_hrs". I add ... (more)

489
views
no
1

## Heart Rate Service hangs while debugging with eclipse on nRF51822 dev kit

Hi,

I set up eclipse according to n-AN29 and imported several of the example projects. The blinky_example project described in the nRF51822 dev kit user's guide works perfectly (I get blinking LEDs). When I try to use the heart ... (more)

885
views
5
2

## Internal Temperature Sensor Details

I am looking for details on the internal temperature sensor on the nRF51822. I would like to use it to get a general ambient reading of the air around the device. Basically, I need to know if this temp sensor ... (more)

841
views
no
3

## why are the random addresses the some?

hi everyone.now i am developing a project with nrf51822.i am using the PCA10000 dongle to see some information of advertising packages. i moved out and pluged in the PCA10001 many times,but the random address are the some ... (more)

259
views
no
1

## Dose the SOFTDEVICE set the NRF51822 to be BLE_GAP_ROLE_PERIPH by default?

and can user change it?or the hardware does not support BLE_GAP_ROLE_CENTRAL?

393
views
no
1

## what kind of GAP Address type does BLE_HRS demo use?

i searched many many times,and i can get the anser.what kind of GAP Address type does BLE_HRS demo use.can someone tell me?tks!

581
views
1
vote
1

## Problem using multiple GPIOTE users

I tried changing the define below from 1 to 2, so I could have one handler for a button and a different handler for other sensors. But my problem is: 1. If I set it to 1, the button handler ... (more)

2k
views
no
7

I get following message when I try to program with the Blinky project a nrf51822 chip: "Error - flash download failed - Cortex M0.

What is wrong?

10k
views
9
2

## What's the maximum of baud rate supported of UART? [closed]

Hi, I have been trying to maximize the baud rate of my uart module, I am using the app_uart layer to control the uart and I have noticed that in your implementation of HCI you have set the baud rate ... (more)

298
views
no
2

## nRF24L01P substitution

Hello,

I've developed a circuit with Mikroelektronika's nRF T click module. This module uses nRF24L01P but as I see I cannot order it because it is obsolete.

Should I use nRF24E1 or nRF24Z1 instead of it? In our ... (more)

3k
views
4
4

## S110 - Sending multiple notifications per connection event

Hello,

1) I want to send multiple notifications (from same characteristic), is that allowed by S110 softdevice?

2) What is the maximum number of packets that S110 could process per ... (more)

1k
views
2
2

## What could make BLE sample applications not work, but radio works ok?

Hi, got an interesting problem, this is on a custom board with nRF51822 QFAB that we are bringing up. The radio test (not using softdevice) works ok and produces strong transmit signal (as strong or even stronger than from the ... (more)

567
views
1
vote
2

## Which protocol for low latency, low power, high rate motion tracking application?

Hi

my application is a 9-axis battery driven motion sensor with a data rate about 144 bit per packet at 1000Hz i have to transmit over air. Low latency (<10ms) is extremely important. The device must consume as low power ... (more)

370
views
no
1

## nRF8002 forcing to sleep

I have an ultra low power application that needs to broadcast it's proximity on a 1sec interval. However, about 75% of the day I would like the device to be powered down and not transmitting.. This should be controlled ... (more)

738
views
1
vote
1

## Does the SoftDevice S110 support 'Direct Advertising'?

I'd like to use 'Direct Advertising' to get the attention of a Central (a specific one or any in range) when an event happens on the peripheral. Is this mode supported by the device / S110? If so, is there ... (more)

4k
views
10
1

## Bonding - difference between IRK and address in whitelist [closed]

Why some devices makes just an IRK entry in Whitelist of SDK and other put the address into? Is it possible to config which entry should be done?

2k
views
2
3

## RAM Banks (RAM retention)

How are the four RAM banks divided up in the nRF51822? Is it an even split of the 16K total RAM (i.e. 4K per block)?

Furthermore, can I expect strange results if I turn on RAM-retention for the 8K ... (more)

832
views
no
1

## Modify clock in gazell on nRF51822

Hello, sirs.

My question is how to configure clock in gazell protocol on nRF51822

I look at the example gzp_dynamic_pairing but that does not have a code part of modifying clock.

I know defining SystemCoreClock on "system_nrf51.c" and i ... (more)

14k
views
2
12

## Keil toolchain/compiler configurations incorrect

Hi all

My target board is nRF51822, and I want to run the heart rate demo project, but a error message when I compile it :

[b]Build target 'nrf51822_xxaa_s110 (256K)' assembling arm_startup_nrf51.s... arm_startup_nrf51.s: error: A3903U: Argument '--pd' not ... (more)

#### Statistics

• Total users: 23170
• Resolved questions: 9878
• Total questions: 23817

## Recent blog posts

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Posted 2017-07-19 06:53:42 by <NAME>
• ### Unique Thread/Bluetooth multiprotocol solution with nRF5 SDK for Thread and nRF52840 SoC by Nordic

Posted 2017-07-14 10:31:56 by <NAME>
• ### nRF Connect macros (currently Android only)

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## Recent questions

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