Just trying out Linux for the first time. I am able to install Ubuntu 18.04 without any problem except for the fact that my screen keeps on spontaneously flickering. It starts to flicker as soon as the system boots up to the login screen (even before entering my password).  Things tried:   Changing between different drivers in the Software & Updates -> Additional Drivers option (nvidia-driver-396, nvidia-driver-390, nouveau) Boot with "nomodeset" Blacklist nouveau Updating kernel to 4.17.4   If there anything else I should try please let me know.

I have been trying to install Ubuntu on my new laptop:     Dell XPS 15 (9570)   Windows 10 Home 64bit English   8th Generation Intel(R) Core(TM) i7-8750H Processor (9M Cache, up to 4.1 GHz, 6 cores)   16GB, 2x8GB, DDR4, 2666MHz   256GB M.2 2280 PCIe Solid State Drive   NVIDIA(R) GeForce(R) GTX 1050Ti with 4GB GDDR5     I began by trying to install Ubuntu 18.04 LTS using an 8GB USB drive. The first issue I ran into was getting frozen on the bootup screen on the fourth dot. After a couple tries, I plugged in my monitor (through HDMI) and it stopped getting stuck all of a sudden.    Next, I tried to go through the installation and when I clicked on restart now, my computer froze and I had to shut it down manually and start it back up again. At this point I got to the login screen and logged in but after entering my password it got stuck on a purple screen with my mouse pointer (which was frozen). I was able to get into a shell at this point (with ctrl+alt+f4) and attempted to run sudo apt-get install nvidia-390 but this froze when it reached building initial module for 4.15.0-22-generic and upon reboot I had to run sudo dpkg --remove -a.    I was unable to work around this so I attempted to install Ubuntu 16.04 which I could only do by adding acpi=off to the boot configuration (which by the way, I had a lot of trouble getting to since GRUB usually flashed in and then immediately disappeared and only occasionally would it stick around long enough for me to use). But when I try to boot up now, I never reach the screen with the five dots and instead immediately get stuck on a purple screen (with no mouse pointer).  I reinstalled Ubuntu 18.04 and am back to being stuck on the log-in screen.  What should I do?


Consider the following sentence as an example. I used some hair spray. What part of speech is hair? Intuitively, I want to say it's an adjective modifying spray since hair spray is two separate words and not a compound noun. Hair spray however, as paired nouns, is something that we've decided to call a thing suggesting it might be a noun or maybe some other part of speech as part of a noun cluster (if such a thing exists). A dictionary entry for hair does not describe hair as an adjective. I can think of several more examples like this:  money order,  pocket comb, tip money.  Are money, pocket and tip adjectives or something else?

I read this recently in :     At the end of the summit, the French and European officials had   claimed a points victory over the Germans by getting them to agree   more firmly to a target date of January 1st next year to entrust the   European Central Bank (ECB) with the ultimate authority to supervise   the euro zone’s 6,000-odd banks.   "Points" is a plural, and I suppose it doesn't function as a noun in this sentence since it's following the article "a", so is it an adjective adorning "victory"?


I am not too much of a chat user, I must say. However, whenever I do use one, the aesthetic appeal is simply not there. There is barely any user interface, and it just generally does not look great. Also, Latex does not seem to be supported, which makes typing math equations extremely difficult to read. I think that with the new toolbar update going live, Stack Exchange is trying to make all of their sites look more appealing, but the chat rooms have never seemed to be updated for appeal. Are we going to see a change soon? Or is it because the chat rooms are not very popular?    Here is a picture of a chat room in Math Stack Exchange:

It would be really nice to be able to use MathJaX (math formulas) in chat.  Not specially for formulae, but for things like $V_{CC}$ in electronics chat would be very useful.


Suppose I live in the US and want to buy an ETF share traded in the US. I would already know how Chinese stock market performed by the time the US market is open because of the 12-hour difference.  Let's say it's 1/21/2020 Tuesday in the morning Eastern Time, which is 1/21/2020 Tuesday evening time in China. If Chinese market gained (and suppose the top 50 stocks by market-cap gained) on 1/21/2020, would I gain if I buy an ETF (traded in the US) that tracks an index composed of top 50 Chinese stocks?   If that's case, is this a 100% win situation? If not, why?  Also, because Chinese market is already closed, why does the ETF price sticll change, if the underline index is not supposed to be changing?  Thanks!!

For example:  Because the NASDAQ: DAX is tracking the index INDEXDB: DAX should its trading value be completely flat when the market the markets are open in the US, but closed in Germany? I'm not seeing that artifact in any of the charts I can find.


After fixing the "System runs in low graphic mode"-error, the resolution of my screen changed to 640x480. Obviously, this is not my native resolution.  I cannot set it to the native resolution (1366 x 768) for some reason, since there is no other resolution shown in the Monitor Settings. Arandr also does not show 1366x768 as a possible resolution.  My laptop is a Samsung R519 with standard resolution 1366x768, with an Intel graphic card.  Does anyone have an idea how to solve my problem? I hope I explained it clear enough (if there is some missing info, please let me know)

I have installed Ubuntu on my desktop, but my monitor don't pass more than 800x600 resolution.  My monitor is good at 1360x768. How can I set resolution at 1380x768 ?


When I run: render_args = bpy.context.scene.render render_args.engine = 'BLENDER_RENDER'  I get the following error: TypeError: bpy_struct: item.attr = val: enum "BLENDER_RENDER" not found in ('BLENDER_EEVEE', 'BLENDER_WORKBENCH', 'CYCLES')  I am using Blender 2.91.0 Alpha.  Why is 'BLENDER_RENDER' missing and how do I fix it?

Blender has just purged the entire game engine from 2.8. There is no "Game Engine" mode anymore and there isn't even a logic editor. I tried installing a GitHub Blender release with the game engine mode working but it failed to install because all the game code was gutted. Does this mean that Blender 2.8 is going to lose the game engine, or is the game engine just being redone for better compatibility and whatnot?


$(a)$ Let's say A person is pushing an object. Then the object will put a force on the person equal to the force the person is putting on the object (because of Newton's third law). Then the person should move backward because of the opposing force. But clearly, the person moves in the same direction as the object while the person pushes it. Is there something wrong with my reasoning? $(b)$ Let's say I am pushing against a wall with force $F$, then the wall will push me with force $F$ (because of newtons 3rd law). Because The wall is pushing me with force F, then I will (because of newtons 3rd law), push the wall with force $F$, this will add up with my previous force to $2F$. If I keep doing this indefinitely, then I can say that I am pushing this wall with a force of $\infty$ $N$ and the wall is pushing me with a force of $\infty$ $N$. That would mean I will get crushed and the wall will get destroyed. But clearly, that does not happen. Again, where am I using Newton's 3rd law in the wrong way?

My father explained to me how rockets work and he told me that Newton's Third Law of motion worked here. I asked him why it works and he didn't answer. I have wasted over a week thinking about this problem and now I am giving up. Can anyone explain why Newton's Third Law works? For reference, Newton's third law:  To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts.


What is it called when single letters are used as words in a sentence?     I C A B.   I C D B P!         I see a Bee.   I see the bee pee!        F U N-E X?   S I F X.   F U N-E M?   S I F M.   OK I L F M N X!      Have you any eggs?   Yes I have eggs.   Have you any Ham?   Yes I have ham.   OK. I will have ham and eggs.   I have been looking for this, at a low level, for years.

IOU stands for I owe you and we pronounce each letter separately. But how do we classify that construction"?   abbreviation: a shortened form of a word or phrase acronym: an abbreviation formed from the initial letters of other words and pronounced as a word Initialism: an abbreviation consisting of initial letters pronounced separately back-formation: a word that is formed from an existing word which looks as though it is a derivative, typically by removal of a suffix      All definitions provided by Oxford Dictionaries Online  It can't be an abbreviation because there is no shortening, clipping or back-formation. Take for example phone which is an abbreviation of telephone, or edit which is a back-formation of editorship and editor. I would argue that abbreviations are words that have been shortened, a faster way of writing or saying something. Another example would be Prof for professor.  It can't be an acronym because we don't pronounce IOU as one word, whereas we do with NATO and RAM.  It can't be an initialism because if it was, it should be written as IOY (I Owe You)  Other examples that spring to mind is CU for see you and YRU for why are you, where initialism would dictate that the proper forms be SY and WAY.   How do linguists define this structure? Is there a more specific term than abbreviation?


If someone has roads all the way around a hex in catan (six roads), and one road on each opposite end of that hex, is that a total of seven towards the longest road or eight.  In other words do both roads on either end count or only one since it goes around in a circle?

If I have 6 roads that go all around a single hex tile, they are a continuous uninterrupted road (assuming none of my opponents interrupts it with their settlements/cities). But, can I continue this 6-piece road and create a 7-piece continuous road by building a road that goes out of this hex tile? Here's an image of what I'm talking about:    Is this a valid 7-piece continuous road?


A snippet of regression code of a stock price data-  forecast_col='Adj. Close' forecast_out=int(math.ceil(0.01*len(df))) df['label']=df[forecast_col].shift(-forecast_out)  X=X[:-forecast_out+1]   What is the meaning of X=X[:-forecast_out+1] ?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I have to show that for every analytic function $f$ on $G \subseteq \mathbb{C}$ (Simply connected open set) such that $f(z) \neq 0, \forall z \in G$, then $\exists$ a function g analytic in $G$ such that $g^2 = f$.   Also, I need to give an example of an open set $G$ which is not simply connected and an analytic function $f$ on $G$ with $f(z) \neq 0, \forall z \in G$ such that $f \neq g^2$ for every analytic function $g \in G$.  I do not see how to approach this problem. If I get the first part, maybe the example will be easier.

$\psi(z) \neq 0$ is a holomorphic function on $D \subseteq \mathbb{C}$. Does there exist a holomorphic function $\varphi(z)$ on $D$ such that $\varphi^2(z) = \psi(z)$? Here $D$ can be a single-connected region or a multi-connected region.   I think for single-connected region, it is true, but I can not prove.


I am new to programming and would appreciate some help. The slightest bit of insight would be highly appreciated.  I have an issue with the following code. The program emulates a calculator but currently my main focus is on if and else if statements. The issue is that no matter what the user selects, the program will always add the two numbers i.e. 'number1' and 'number2' in the code  import java.util.*; public class Input {     private Scanner input;      public Input()     {          input = new Scanner(System.in);      }      public void calculation()     {         double number1, number2, answer;         String A, B, C, D, E;         String option;         A = "A"; B = "B"; C = "C"; D = "D"; E = "E"; //initialising the strings           System.out.println("add - option A \t (if your option is A, insert 'A')");         System.out.println("multiply - option B");         System.out.println("subtract - option C");         System.out.println("divide - option D");         System.out.println("power - option E (1st number - 'X' & 2nd number - 'n' following X^n)");         System.out.println("Remember Java is case sensitive, therefore, inserting 'a' as 'A' won't work");         System.out.println();         System.out.println("Insert your first number: ");         number1 = input.nextDouble();         System.out.println("Insert your second number: ");         number2 = input.nextDouble();         System.out.println("Choosing option: ");         option = input.next();          if(A == A)         {             answer = number1 + number2;             System.out.println("Your answer is: " + answer);         }          else if(B == B)         {             answer = number1 * number2;             System.out.println("Your answer is: " + answer);          }else if(C == C)         {             answer = number1 - number2;             System.out.println("Your answer is: " + answer);          }else if(D == D)         {             answer = number1 / number2;             System.out.println("Your answer is: " + answer);          }else if(E == E)         {             answer = Math.pow(number1, number2);             System.out.println("Your answer is: " + answer);          }else         {             System.out.println("Choose a suitable option");          }         } }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I’m trying to remember the name of a book I can only just remember. It was for older children, and was something about "the Wall", and north of it are ancient and scary otherworldly forces (but not A Song of Ice and Fire). I think a group of children, from a school on the border by the wall, end up being the heroes and the novel ends with a battle in the school.

I'm trying to remember a book set in an alternate England with a walled-off section that contains undead and other magical phenomenons, which can be controlled and dispelled by playing special musical bells. The owner of these bells is the main character's father, and is responsible for maintaining peace between the walled-off area and the rest of England. When he is captured by a powerful undead, the main character goes into the walled-off land to rescue him using her own set of bells.


Does anyone have information /can point out reliable source on Iceland Covid restrictions for tourist travelling to Iceland in July 2020 ?

Due to the outbreak of nCoV-19 (Novel Coronavirus) many Countries have imposed several entry restrictions. But these are quite confusing for a lot of people. Some countries allow transit through parts of China (like Shanghai) but some restrict transit even through Hong Kong/Macau. Philippines restricted passengers coming from Taiwan too, but I think that that was later changed.  Where can one find a list of such restrictions for all the countries, ideally a source that is updated frequently


I had initial plans to travel to Spain and got my visa, but due to my partner's work schedule had to cancel the plan to Spain and am now planning to go to France. Will it be an issue if I do not go to Spain and straightaway go to France with the visa issued by Spain?  Not sure of the practice. Thanks for your inputs.

In case, if I get a multiple-entry Schengen visa in one of the embassies in Ukraine, Kyiv - should my first trip be to the country which issued the visa?  Any there any requirements of this sort? Does this condition vary depending on embassy which issued the visa?  What are the possible consequences on not visiting that country first? Does it somehow depend on country where the embassy is (i.e. non-Schengen and not EU members)?


I'm confused by why there are so many separate sites for specific languages on here. Wouldn't it be better to just have one "Languages" Stack Exchange where you can indicate which language you're asking about with the tags? As it is, if I want to ask about ancient Greek dialects I have to post on the "Latin" Stack Exchange, and if I have a question about Ghandaran or Pali I have to go to the "Buddhism" one, and if I have a question about Klingon grammar I have to post on the Sci-fi and fantasy site (where it will most likely be closed as off-topic). As far as I know there's nowhere for me to ask about Toki or Ithkuil (although perhaps the Esperanto site might accept a question about these languages). Just wondering about the rationale for having so many separate sites. Is it possible to merge them all into one "Languages" site where any and every language would be on-topic?

There are a quite a few language learning related sites on the Stack Exchange network. I may have missed a few, but here they are:                      It would be nice to have a single language related site and use tags when asking questions about a specific language. Stack Overflow already does something similar for programming languages.  Benefits   Automatic support for minority or endangered languages. There are thousands of languages that will never have enough support to create their own SE site. Yet many have a core group of learners and researchers that would benefit from being able to ask and answer questions just by adding a new tag.  Cross-language questions. Many languages are related to each other. A common site would make it easy to ask a question about something that covers two languages. Just add both language tags. Cut down on the proliferation of new SE sites. I don't know that having lots of sites is necessarily bad, but sometimes less is more. Better search engine results. I can't guarantee this one, but it seems likely. Stack Overflow is always near the top for programming language questions, but I rarely find SE language sites when I search for English or Chinese related questions.   I suppose that everyone is too entrenched in their own communities now to change, but I thought I would suggest it anyway.


Is there a way to block a specific folder's files from showing up in the Unity search?

I sometimes browse erotic media files but I would like to avoid having them appear in files & folders / recent. How can I do that?  The old "making .recently-used.xbel a folder" trick from 10.10 and older doesn't work any more.   Plus I'd prefer to turn off tracking only temporarily.  I also prefer not to use a separate user for this, as switching users sometimes isn't fast enough.


The truth potion (Veritaserum) is one of the most powerful potions that forces the drinker to speak truth. Then why didn't Ministry used it in any criminal cases instead of long discussions and proceedings? I know there are antidotes to the potion (Dumbledore tells Harry in the 6th book , "Slughorn might have been carrying antidote to veritaserum ever since I asked him about the memory"), but why don't keep criminals in custody until the effect of the antidote wears out and then make them drink veritaserum. Won't that result in perfect judgement?

Reading through the books once again, I came to ask myself:  What "truth" is told whilst being affected by veritaserum? Is it the objective truth or what one believes to be true?  Regardless of how the answer is I see many problems arising from this, but also some great ideas.


Is there any specific name for this type of question or statement?   If I ask someone a yes/no type question  "Have you lost your mind?"   then either answer(yes or no) is degrading to the person replying.  No - ok you never had it.  Yes - could mean he has gone crazy.  There could also be a statement made to a person, which if that person refutes he is shown in bad light or even if he agrees, it is bad for him. Is there any name for such device?   Any examples of such devices(questions or statements) where I could read more of this type.

For example, if I ask someone "What does it feel like to be a gay Christian?" I'm suggesting that the person to whom I'm asking is gay and Christian, neither of which may be true.


I have been given an assignment where I need to check if a Booking Reference is valid. The Booking Reference has to be in the style of "ABC-1234". I need to use PHP to check the first three letters are either "ACT ABQ BDE". This is then followed by the "-". Then I need to check the numbers are in the following sequence, the first digit is either "1" or "2", and the following three digits are in the 0-9 range. This is the code I currently have to check this:   if (isset($webdata['bookingreference']  ))  {   if (!preg_match("/^ [ACT] [ABQ] [BDE] - [(1),(2)]{5}[0-9]{6,}$/", $webdata['bookingreference']))  {     $formerror['bookingreference'] = 'Not valid on server: Invalid booking reference';     $valid = FALSE;   }   However, when I test this, I always get the message it is valid no matter what the sequence is. Any help is much appreciated!!

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


I just wanted to know if there's anything built into the .net framework where I can easily return the delta between two numbers?  I wrote code that does this but it sounds like something that should be in the framework already.

I need the perfect algorithm or C# function to calculate the difference (distance) between 2 decimal numbers.  For example the difference between: 100 and 25 is 75 100 and -25 is 125 -100 and -115 is 15 -500 and 100 is 600  Is there a C# function or a very elegant algorithm to calculate this or I have to go and handle every case separately with ifs.  If there is such a function or algorithm, which one is it?


Suppose $X_1,X_2,\cdots,X_n$ are iid uniform random variables on $[a,b]$, what is the distribution of $$Y_n=\frac{\max_{1\le i\le n}X_i+\min_{1\le i\le n}X_i}{2}?$$

Let $X_1,X_2, \ldots , X_n$ be independent and identically distributed Uniform random variables on the interval (0, a) for a > 0, each having a density function $f(x) = \frac{1}{a}$, $0<x<a$. Let $X_{(1)},X_{(2)}, \ldots , X_{(n)}$ denote the order statistics. The range of the data is defined as $R = X_{(n)}−X_{(1)}$ and the midrange is defined as $V = \frac{1}{2}(X_{(1)}+X_{(n)})$ Derive the joint distribution of $(R, V )$ and deduce the marginal distributions of $R$ and $V.$  Attempt:   First I am attempting to generate the joint distribution of $(V,X_{(1)})$ and then integrate out the $X_{(1)}$.   For the joint distribution of $(V,X_{(1)})$ I have:   $$ f_{v,x_{(1)}}(v,x_{(1)})=2n(n-1)\int_{-\infty}^v [F(2v-x_{(1)})-F(x_{(1)})]^{n-2} f(2v-x_{(1)})f(x_{(1)}) \, dx_{(1)}$$  At this point I have no idea how to integrate out the $x_{(1)}$.  Edit: I have located the joint distribution of the range and mid-range:  $$ f_{r,v}(r,v) = n(n-1) \left[F\left(v+\frac{r}{2}\right) - \left(F\left(v-\frac{r}{2}\right)\right)\right]^{n-2} f\left(v-\frac r 2 \right) f(v+\frac{r}{2})$$  For each marginal distribution, I have to integrate out:  $$ f_r(r) = \int_{-\infty}^\infty n(n-1)[F(v+\frac{r}{2})-(F(v-\frac{r}{2})]^{n-2}f(v-\frac{r}{2})f(v+\frac{r}{2}) \, dv$$  $$ f_v(v) = \int_0^{\infty}n(n-1)[F(v+\frac{r}{2})-(F(v-\frac{r}{2})]^{n-2}f(v-\frac{r}{2})f(v+\frac{r}{2}) \, dr$$


I'm currently unit testing .NET application with NUnit framework. Some of the methods we use involve getting X509Certificate2 object as input and checking if one or more properties match certain crateria. For example, method that check whether the thumbprint exists in a very specific list. Thus, I need a way to mock or fake the X509Certificate2 object so that I can control what the thumbprint field will return or what are the extentions list will contain. One way I can approach this is to create the special certificates and use them as resources in the tests project (hard coded or embedded resource). I'm searching for a different solution, if it's even possible. And suggestions will be greatly appreciated! Thanks in advance :)

can be quite a pain.  I currently favor an  to handle this, but something about just keeps feels weird.    So, What is the best way you mock sealed classes?  Java answers are more than welcome.  In fact, I would anticipate that the Java community has been dealing with this longer and has a great deal to offer.  But here are some of the .NET opinions:


A post that doesn't exist is shown on the "Top network posts" section on this . The title is called "6", and the URL of the post leads to this .

I discovered a strange, blank link in 's Top Network Posts:        The above link and screenshot are of the user's Unix & Linux site profile, but this issue can be reproduced on any of the user's site profiles other than Meta Stack Exchange (as the blank post appears to be on this site, and posts from the same site are excluded).  The link seems to go to , which features a really negative question ID (close to the lowest value that can be represented by a 32-bit signed integer, specifically -(2^31) + 1005), and lacks the title in the URL that is present in all of the other links. It leads to a 404 error.  Going to the  seems to go to an actual answer on a question migrated to this site, which happens to have a score of 13 (as of the time this was asked).  Why is the question ID incorrect here? Based on the duplicates, it seems that this affects posts (both questions and answers) that were migrated from other sites: somehow, the question ID seems to be getting messed up.  Update: It looks like the above linked user has deleted their account on this site, so the issue cannot be reproduced on the profile I originally reported. It can, however, be reproduced on . The errant link in that profile is , and the errant question ID seems to also be close to the lowest possible 32-bit signed integer, -(2^31) + 3412.


I was reading an article about the existence of exotic spheres in 7 dimensions, my initial instinct was that that was pure mathematics and most likely inapplicable to any natural sciences. Then I remembered string theory used 10 spatial dimensions, so, are there structures in string theory that are equivalent to exotic spheres? Does it imply that the metric of space-time becomes non-smoothable, despite being continuous?

Basically an exotic sphere is topologically a sphere, but doesn't look like a one. Or more accurately:     homeomorphic but not diffeomorphic to the standard Euclidean n-sphere   The first exotic spheres were constructed by John Milnor (1956) in dimension n = 7 as S3-bundles over S4.  It looks like an SU(2) gauge field on S4? But I don't know more about this? I guess there is lots of expertise here. Could you give a physical interpretation of this 7 sphere? Just to make it more intuitive.    Thank you!


I'm using the ieeeaccess.cls for IEEE Access journal but I get the following error,  Missing number, treated as zero. \xdef   My code is as follows,  \documentclass{ieeeaccess}  \usepackage{amsmath, amsfonts, amssymb, color, enumerate, amsthm, graphicx} \usepackage{tikz, subcaption, cite} \usepackage{color, xcolor, soul, bm, textcomp} \usepackage{marginnote} \PassOptionsToPackage{hyphens}{url}\usepackage{hyperref} \hypersetup{   colorlinks   = true, %Colours links instead of ugly boxes   urlcolor     = blue, %Colour for external hyperlinks   linkcolor    = blue, %Colour of internal links   citecolor    = green %Colour of citations }  \renewcommand{\qedsymbol}{$\blacksquare$} \usepackage[normalem]{ulem} \newtheorem{problem}{Problem} \newtheorem{theorem}{Theorem} \newtheorem{corollary}{Corollary} \newtheorem{assumption}{Assumption} \newtheorem{proposition}{Proposition} \newtheorem{lemma}{Lemma} \newtheorem{remark}{Remark} \newtheorem{definition}{Definition} \newtheorem{example}{Example} \usepackage{epsfig}  \usepackage{psfrag} \DeclareMathOperator{\diag}{diag} \usepackage{tcolorbox}  \usepackage{algorithm} \usepackage{algpseudocode} \allowdisplaybreaks  \def\BibTeX{{\rm B\kern-.05em{\sc i\kern-.025em b}\kern-.08em         T\kern-.1667em\lower.7ex\hbox{E}\kern-.125emX}}   \def\endtheorem{\hspace*{\fill}~$\square$\par\endtrivlist\unskip} \def\endlemma{\hspace*{\fill}~$\square$\par\endtrivlist\unskip} \def\endproposition{\hspace*{\fill}~$\square$\par\endtrivlist\unskip} \def\endexample{\hspace*{\fill}~$\square$\par\endtrivlist\unskip} \def\endremark{\hspace*{\fill}~$\square$\par\endtrivlist\unskip} \def\enddefinition{\hspace*{\fill}~$\square$\par\endtrivlist\unskip}  \begin{document} \history{Date of publication xxxx 00, 0000, date of current version xxxx 00, 0000.} \doi{10.1109/ACCESS.2017.DOI}  \title{My title}  \author{\uppercase{Mohammad}\authorrefmark{1}} \address[1]{Department of Electrical and Computer Engineering (e-mail: myemail@mydomain.edu)}  \markboth {Author \headeretal: Preparation of Papers for IEEE TRANSACTIONS and JOURNALS} {Author \headeretal: Preparation of Papers for IEEE TRANSACTIONS and JOURNALS}  \corresp{Corresponding author: Mohammad}  \newcommand{\ty}{\color{yellow}} \newcommand{\tb}{\color{blue}} \newcommand{\tr}{\color{red}} \newcommand{\tg}{\color{green}}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{abstract} My abstract ... \end{abstract}  \begin{keywords}     My keywords ... \end{keywords}  \titlepgskip=-15pt  \maketitle  \section{Introduction} \label{sec:introduction} \PARstart{T}{his} is my document.  %\appendices %\input{Appendix}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \bibliographystyle{IEEEtran} \bibliography{IEEEabrv, refs}  \EOD  \end{document}

When I include a  \usepackage{forest} all colored text title, section headings disappears with IEEE Access journal template How can I tackle this problem?


I am working in a project with both QGis and ArcGIS. I do mostly cosmetic work and digitalize with QGIS then transfer the shapefiles on ArcGIS. At work I am the only one to work on QGIS, the other members have ArcGIS, (not our choice, question of tight budget). This also mean I have no support, no one is familiar with the program.  This worked fine as long as I was only transfering ready files to ArcGIS, but lately I worked for a short time on the files in ArcGIS (I projected the files and edited) and eventually I had to take back the files from ArcGIS and edit further with QGIS.  When I send back those files in ArcGIS they are messed up.  The edited shapefiles are right on QGIS (topology fine, TOC fine), but on ArcGIS I have "fantoms" polygons or objects (without any geometry) AND overlapping polygons: the old version of the edited polygon/object plus the new polygon/object.  Though I have a column with unique IDs to help sort that out, some of the fantoms/old polygons get a "0" for ID some other the same ID as the original polygon.   So I delete the mistakes in ArcGIS, the file is fine according to ArcGIS. I double check on QGIS, and surprise, I am now missing polygons there!  This is becoming a big mess, and I am unable to understand where are my mistakes coming from so I can avoid them in the future.  I also have problems with special signs (Swedish signs, ö, ä, å) translating in other signs or letters from on program to the other. I have made some reference excel table to join to the gibberish TOC, but when constantly editing, it is complicated to keep track of the newest version. Any other solution is welcome!

This tiny little script deletes all small features in all layers. This works fine but the size of .shp files are not reduced. Please tell me why...  canvas = iface.mapCanvas() expr = QgsExpression("$length<100") for l in canvas.layers():     l.startEditing()     it = l.getFeatures(QgsFeatureRequest(expr))     for ft in it:         l.deleteFeature(ft.id())     l.commitChanges()


Is it a way to create a document in such a way that the numbering of the sections is independent of that of the chapters?  e.g.:    Chapter 1    section 1    section 2 Chapter 2    section 3    section 4    section 5 Chapter 3    section 6    section 7

Some document elements (e.g., figures in the book class) are numbered per chapter (figure 1.1, 1.2, 2.1, ...). How can I achieve continuous numbering (figure 1, 2, 3, ...)?  And vice versa: Some document elements (e.g., figures in the article class) are numbered continuously. How can I achieve per-section numbering?  \documentclass{book}% for "vice versa" variant, replace `book` with `article`  \begin{document}  \chapter{foo}% for "vice versa" variant, replace `\chapter` with `\section`  \begin{figure} \centering \rule{1cm}{1cm}% placeholder for graphic \caption{A figure} \end{figure}  \end{document}   Bonus question: Is it possible to adjust the numbering of the sectioning headings themselves? Can I, e.g., switch from per-chapter to continuous numbering of sections in the book class?


I tried the following  int number = ThreadLocalRandom.current().nextInt(1000, 9999 + 1);   But it won't generate 4 digit numbers like 0004,0035 and so on...  I searched for similar questions but none solved, they were different from what I need, if there's already an existing question please let me know.  I need no genarate numbers like 1485 and 0180, not only numbers starting with 0.

How do you left pad an int with zeros when converting to a String in java?  I'm basically looking to pad out integers up to 9999 with leading zeros (e.g. 1 = 0001).


As requested, I am asking the  here.   Is there a way to find a load on my web application server without a load / stress testing?  I have deployed my application in the Apache Tomcat server. As per as I know, each web server have some limitations on serving a request, beyond which, performance degrades. e.g. If a server can handle 800 requests happily, concurrently, the more requests landing on the server will get delayed response, or may be dropped.  I am looking for some alerting mechanism by which I will get to know that the load on my web server has crossed the threshold limit, and accordingly I will able to take the required actions like e.g. adding one more node behind load balancer to distribute the load.

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


I wish to ping three local devices, every 5 min, without stopping, from a Raspberry Pi running Raspbian OS. When my Pi powers on, I want that to automatically start.     I saw an  about it, but not sure where to start.

I'd like to run a command at startup which pings a certain address every 10 minutes and writes the result to a file. I've figured out now how to do the pinging and file writing and the 10 min intervals:  while true; do my-command-here; sleep 600; done   My question is, can I put this in /etc/init.d/rc.local or should I be putting it in /etc/rc.local or somewhere else entirely? I'm specifically concerned because it's an infinite loop so I'm not sure if I could put it in one of these startup scripts.  Some help would be appreciated. I'm using Ubuntu 12.04.5


This is actually a Lipschitz function, so thought I should show that it's a Cauchy sequence. I assumed that $f(x_n)=x_{n+1}$. Putting $x=x_{n-1}$ and $y=x_{n-2}$, we get $$|f(x_{n-1})-f(x_{n-2})| \le \frac 12 |x_{n-1} - x_{n-2}|$$ This gives us, $$|x_n - x_{n-1}| \le \frac 12 |x_{n-1} - x_{n-2}|$$ Which ultimately gives that $$|x_n - x_{n-1}| \le \frac{1}{2^{n-2}} |x_2-x_1|$$ Now, I don't know how to proceed from this.....

I'm interested in convergence of $f(x_n)=x_{n+1}$ and often hear this term referenced.  What does it mean to be a contraction mapping in the context of the sequence of real numbers given by $f(x_n)=x_{n+1}$? And what does it tell us about such sequence?  A search online gives the answer given by Wikipedia, that it is a function $f$ defined on a metric space $(M,d)$ from $M$ to itself with the property that for some real number $k \in [0,1)$,  $$d(f(x),f(y)) \leq k d(x,y)$$  This definition is quite unhelpful because I barely know what a metric space is. I feel like this definition is to generalized, and I'm interested in in the specific case of recursively defined real sequences $f(x_n)=x_{n+1}$ that there should be a more specific answer to my question.


This is probably a very simple question but I am new to C# and can't figure out how to get the value of my enum?    public enum Status     {         OK,         Bad,     }   I want to display it as follows (hard coded at the moment):   public Task<ResultData[]> GetResults()         {             var dummyData = new ResultData();             dummyData.Title = "title";             dummyData.Status = Status.OK;             dummyData.Value = 5;              var results = new ResultData[] { dummyData };             return Task.FromResult(results);         }    However this shows the status as 0 not OK. I want it to show OK in the array when I use this GetResults() method. I have tried Status.OK.ToString() as many other posts have suggested but I get the error that it cannot convert the string to the type Status. I have looked at other articles but cannot seem to figure out a simple way of doing this - can anyone assist?   Thanks

Which is the preferred way to convert an Enum to a String in .NET 3.5?   Enum.GetName Enum.Format ToString   Why should I prefer one of these over the others? Does one perform better?


My original objective was to find the arc length of $\sin x$ on the interval $[0, 2\pi ]$. Of course the traditional way to calculate arc length is to use the formula: $$L = \int_a^b \sqrt{1 + (f'(x))^2} dx$$. And so obviously the formula becomes in this case: $$\int_{0}^{2\pi} \sqrt{1 + \cos^2 x} \ dx$$ But I am stuck here. Does anyone know of any analytical methods to anti-differentiate $\sqrt{1 + \cos^2 x}$, if any exist at all?

What is the length of a sine wave from $0$ to $2\pi$? Physically I would plot $$y=\sin(x),\quad 0\le x\le {2\pi}$$ and measure line length.  I think part of the answer is to integrate this: $$ \int_0^{2\pi} \sqrt{ 1 + (\sin(x))^2} \ \rm{dx} $$  Any ideas?


My knowledge in vector space and quantum mechanics is weak and I am trying to understand and make sense of the question that I asked. It will be very helpful if someone could explain it to me in a conceptual and deeper sense.

In , why is it that a self-adjoint operator is linked to an observable? What makes it measureable? And why isn't a non-Hermitian operator linked to an observable?  Also, what type of observables are we talking about here? Particles?


I've come to like starting all my sessions with a   prompt $D$H$H$H$H$H$H$H$H$H $T$H$H$H $P $_   Is there a way to just save it so it does it itself?

How can I permanently change the contents of the command prompt under Windows 7? I know about the prompt command, and the , but I'm not sure where to save the custom prompt so that it's used every time. Old web pages say autoexec.bat, but that seems to be an uneditable dummy file under 7.


"Do you know why they act like that?"  Do native speakers pronounce the "t" after the "c" and before the "l" in the sentence above? I'm under the impression that they don't do it and just say "ac like that." Is this just my impression?

when the phrase "Can't complain" is pronounced [ˈkænt kəmˈpleɪn] I think that the T is dropped in fast speech because of the alveolar plosives. Right? I read that when T comes before these letters: / s, f, n, l, p, k / it's silent.  I know that in American English the T is held in "I can't do it" but above I'm talking about dropping it completely. I recorded myself:  Does it sound okay?


I decided to dual boot Ubuntu 14.04 with Windows 8. Everything went right during the process (partitioning, installing, etc) but upon rebooting my laptop (my laptop is an HP Pavilion G6) it booted straight into Windows 8 with no GRUB menu to be seen. I attempted to use boot repair on Ubuntu and that failed; I also tried to change the boot order in the BIOS although I'm not really sure what I'm doing there so I don't know if I did it right or not.   Some help would be brilliant as I'm not sure how to go about getting the GRUB menu back!

I have installed Ubuntu 15.10 alongside Windows 10 with UEFI. To install Ubuntu, I chose the option install alongside Windows 10 or something similar to this. Then I created a new partition for Ubuntu and installed it. After installation, the boot menu did not show up. Initially I thought Ubuntu has not been installed, but when I plugged in the USB drive and wanted to install Ubuntu I saw an option of reinstalling Ubuntu on my machine. So, I found out that Ubuntu is installed. Pressing F8 and F12 also does not help. Can anyone help me bring up the GRUB boot menu? In Windows, I also entered the command bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi in cmd, but still the boot menu does not show up.  Reply (Himanshu) : Just boot in bios and, if you can, add boot option with name say ubuntu and path EFI/ubuntu/shimx64.efi. No need for live PCB or anything. Move the boot option to top. This is for dell GUI bios but I assume it works for all. Or you may want to see  or , where you can enable Windows Boot Loader for one boot or forever as you wish, and boot Ubuntu from it. If you want now, you can use the installed Ubuntu terminal to use the commands update-grub to use GRUB instead. (Not enough reputation to answer properly btw.)


I coded my own website and uploaded to a host. Some days ago I realized that in front page suddenly redirects to an unknown websites, until 3-4 redirects.  The redirects ends up at: http://59016823.g05.info/?p=NGNmN2JjNTYyNmIwMGE3YTU5MjgzNmNiOWNjOWMzNGF8MXxEaXJlY3RMaW5rfFRYbFBZbVoxWTJGMFpTQkNiMlI1VEdGNVpYST18MTAwMHw1OTAxNjgyMw==

This is a  about Server Security - Responding to Breach Events (Hacking)   See Also:                  Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism:   What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning?   Original Version       2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a    attack on our provider. The servers access to the Internet   has been shut down which means over 5-600 of our clients sites are now   down. Now this could be an FTP hack, or some weakness in code   somewhere. I'm not sure till I get there.      How can I track this down quickly? We're in for a whole lot of   litigation if I don't get the server back up ASAP. Any help is   appreciated. We are running Open SUSE 11.0.            2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed   to resolve this problem, although it may not apply to many others in a   different situation. I'll detail what we did.      We unplugged the server from the net. It was performing (attempting to   perform) a Denial Of Service attack on another server in Indonesia,   and the guilty party was also based there.      We firstly tried to identify where on the server this was coming from,   considering we have over 500 sites on the server, we expected to be   moonlighting for some time. However, with SSH access still, we ran a   command to find all files edited or created in the time the attacks   started. Luckily, the offending file was created over the winter   holidays which meant that not many other files were created on the   server at that time.      We were then able to identify the offending file which was inside the   uploaded images folder within a  website.      After a short cigarette break we concluded that, due to the files   location, it must have been uploaded via a file upload facility that   was inadequetly secured. After some googling, we found that there was   a security vulnerability that allowed files to be uploaded, within the   ZenCart admin panel, for a picture for a record company. (The section   that it never really even used), posting this form just uploaded any   file, it did not check the extension of the file, and didn't even   check to see if the user was logged in.      This meant that any files could be uploaded, including a PHP file for   the attack. We secured the vulnerability with ZenCart on the infected   site, and removed the offending files.      The job was done, and I was home for 2 a.m.            The Moral   - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole   world is made aware of the vulnerability.   - Always do backups, and backup your backups.   - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server   Fault.


I have several "ArrayList"  Like this:   ArrayList<Integer> list1; ArrayList<Integer> list2; ArrayList<Integer> list3;       list1: [0,1,2]   list2: [22,12,23,24,53]   list3: [21,43,21,7]   I want to put all elements of all lists into one ArrayList like  sumList [0,1,2,22,12,23,24,53,21,43,21,7]   How is that to be done?  thx u

Conditions: do not modify the original lists; JDK only, no external libraries. Bonus points for a one-liner or a JDK 1.3 version. Is there a simpler way than: List<String> newList = new ArrayList<String>(); newList.addAll(listOne); newList.addAll(listTwo);


Is it supposed to look differently in a list?  Some examples:  keyword    keyword   keyword ← this looks weird      keyword   keyword ← and this       keyword keyword      keyword ← this too

Looking at the following screenshot of , you'll notice a slight difference in padding of inline code inside normal paragraphs and that of code inside of lists:    The same is true for inline code within comments appearing in my recent activity tab, e.g.    whereas in the original comment the padding looks correct:    Firebug said to me that there is a CSS rule for this:  .comment-text code {     padding: 1px 5px; }   (as well as p code for normal paragraphs), but this isn't applied to inline code in lists, nor in the activity tab.  I can imagine that this is done to save space within lists and the recent activity tab, but at least it doesn't look consistent.


Pi is infinite, but not random. 1/3rd for example is certain not to contain a 4, but i found my full birthday in Pi. Is there proof that every conceivable combination of numbers, such as all Natural numbers in order? I'm having a hard time imagining how all natural numbers could have something before and after them though so can it be proven that every finite numbercombination is found in Pi, such as every birthday of every person in chronological order and everyones creditcard pin and then some. Or is it likely/unlikely/impossible(or impossible to tell)? I'm asking out of my own curiosity.

I came across the :    Which states:     $\pi$ Pi      Pi is an infinite, nonrepeating $($sic$)$ decimal - meaning that   every possible number combination exists somewhere in pi.  Converted   into ASCII text, somewhere in that infinite string of digits is the   name of every person you will ever love, the date, time and manner    of your death, and the answers to all the great questions of    the universe.   Is this true? Does it make any sense ?


I have re-installed Ubuntu from 16.04LTS 64 bit to 14.04LTS 64 bit. I have lost the previous partitions (NTFS) and now, Ubuntu recognises everything as single partition.   Can some one advice the recovery steps to get the old partition table?

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


I need to find a combinatorial proof of this identity   $$\sum_{k=0}^{n}(-1)^{k}\binom{n}{k}\binom{2n-2k}{n-1}=0.$$  I think inclusion exclusion is the best method here. But I"m having a really hard time coming up with a set to count. Permutations don't work here.   A hint would be really nice. Thanks.

How do I prove the following identity:  $$\sum_{k=0}^{n}(-1)^k\binom{n}{k}\binom{2n - 2k}{n - 1} = 0$$  I am trying to use inclusion-exclusion, and this will boil down to a sum like inclusion-exclusion, and the $\binom{2n-2k}{n-1}$ term wouldn't matter (it will be equivalent to set sizes). Is this a correct way to go?


Surface tension has really made me crazy!  Surface tension occurs at the interface of air & water. It is a force per unit length tangential to the intersurface.  But what actually causes it?  One explanation is that there are very less no. of molecules on the interface, remaining far away from each other. Due to this, greater attractive force does exist which causes surface tension. Now, the question is why the density is low.  Another explanation that my book also vaguely offers is the asymmetric downward force on the water interface. But question evidently arise, if the force is downward, how can it produce a tangential surface tension??  Now, what should be the answer to these mind-chocking questions? And are these explanations linked with each other( which I greatly believe)??

A text says:     The surface tension of a liquid results from an imbalance of intermolecular attractive forces, the cohesive forces between molecules:   A molecule in the bulk liquid experiences cohesive forces with other molecules in all directions.   A molecule at the surface of a liquid experiences only net inward cohesive forces   If this is the case: Why is surface tension considered or experienced as a force parallel to the interface while it is so obvious that it must be perpendicular to it?


How does the unix command line program know what file to read?  For example:   cat someFile | foo   How does the program foo know which file to read, and which process is responsible for opening and reading the file from disk?

When I just used pipe in bash, I didn't think more about this. But when I read some C code example using system call pipe() together with fork(), I wonder how to understand pipes, including both anonymous pipes and named pipes.  It is often heard that "everything in Linux/Unix is a file". I wonder if a pipe is actually a file so that one part it connects writes to the pipe file, and the other part reads from the pipe file? If yes, where is the pipe file  for an anonymous pipe created? In /tmp, /dev, or ...?   However, from examples of named pipes, I also learned that using pipes has space and time performance advantage over explicitly using temporary files, probably because there are no files involved in implementation of pipes. Also pipes seem not store data as files do. So I doubt a pipe is actually a file.


According to the truth table, If $P$ is false,then $P->Q$ is true.  if pigs fly, then $1+1=3$. Why is this implication true? How do you prove it?

In propositional logic, the statement "If pigs can fly, then elephants can lay eggs." validates to true because the antecedent validates to false.  In other words, given $a \rightarrow b$, if a is false, the entire statement is true. Why?  Just because the antecendent is false doesn't mean that another fact depends on it, right?


I became good friend with the man I met yesterday.   I became good friend{s} with the man I met yesterday.  Should "friend" be in plural or singular? Which one is right: "friend" or "friends"?

I was reading BBC culture page ( See  ). In the middle of the text, we see:  He became firm friends with the Shakespeare and Company owner in a relationship that lasted until his death 40 years later.  Q1: Does the writer make a mistake? Q2: Why has the writer used the plural form of "friend"?


I'm trying to add a regex pattern to a HTML5 input which has the type of email. I want to invalidate the input if the proceeding character after the @ symbol doesn't contain at least a single character or number, followed by a dot followed by another character or number, e.g: example@example.com // valid because of "e.c" example@example.    // invalid because "e."  I want to retain the default browser validation for email and thus so far have this pattern that seems to match the first valid example I pasted? But looks untidy? \@([a-zA-Z0-9\/.&\s-].[a-zA-Z0-9\/.&\s-])

Is there a regular expression to validate an email address in JavaScript?


Is it possible to construct confidence intervals for a mean of weighted means using standard errors?  I have 4 different weighted means ($p_t = \sum_{i=1}^{n} w_ip_i $ where $w_i$ is the respective weight) for $t = 1,2,3,4$ time periods, with $n = 16$: \begin{equation} \bar p_1 = 378.0494 \quad \bar p_2 = 349.1045 \quad \bar p_3 = 339.0127 \quad \bar p_4 = 338.8679 \end{equation} with corresponding standard errors: \begin{equation} s_1 = 43.668 \quad s_2 = 42.133 \quad s_3 = 40.465 \quad s_4 = 40.084  \end{equation} Calculating a moving average ($\hat P_m$) of these: \begin{equation} \hat P_m = 351.2586 \end{equation} Corresponding standard error: \begin{equation} s_{\hat p} = 9.246 \end{equation}

Imagine that you repeat an experiment three times. In each experiment, you collect triplicate measurements. The triplicates tend to be fairly close together, compared to the differences among the three experimental means. Computing the grand mean is pretty easy. But how can one compute a confidence interval for the grand mean?  Sample data:  Experiment 1:   34, 41, 39  Experiment 2:   45, 51, 52  Experiment 3:   29, 31, 35  Assume that the replicate values within an experiment follow a Gaussian distribution, as does the mean values of each experiment. The SD of variation within an experiment is smaller than the SD among experimental means. Assume also that there is no ordering of the three values in each experiment. The left-to-right order of the three values in each row is entirely arbitrary.  The simple approach is to first compute the mean of each experiment: 38.0, 49.3, and 31.7, and then compute the mean, and its 95% confidence interval, of those three values. Using this method, the grand mean is 39.7 with the 95% confidence interval ranging from 17.4 to 61.9.   The problem with that approach is that it totally ignores the variation among triplicates. I wonder if there isn't a good way to account for that variation.


I partitioned my hard drive and installed Debian on second partition. In order to do this I had to switch from BIOS to UEFI after basically destorying the MBR. Everything works great.  However when I choose to boot to Windows 10 my various images within Hyper-V are not starting.  The error states that hypervisor is not running.  Any ideas?  I tried this  but no joy.  Any suggestions on why this would have stopped working?  C:\Users\User\Desktop>Coreinfo.exe -v  Coreinfo v3.31 - Dump information on system CPU and memory topology Copyright (C) 2008-2014 Mark Russinovich Sysinternals - www.sysinternals.com  Intel(R) Core(TM) i5-3340 CPU @ 3.10GHz Intel64 Family 6 Model 58 Stepping 9, GenuineIntel Microcode signature: 00000020 HYPERVISOR      -       Hypervisor is present VMX             *       Supports Intel hardware-assisted virtualization EPT             *       Supports Intel extended page tables (SLAT)

I've created and run Hyper-V guests on this machine in the past. VT extensions are enabled in the BIOS; no changes made there. I've changed my boot device order recently. How can I ensure that Hyper-V's host hypervisor is started on Windows startup? When attempting to start a VM, the Hyper-V Manager error shows:  An error occurred while attempting to start the selected virtual machine(s). Failed to restore virtual machine state. Virtual machine 'Windows 10 Tech Preview' could not be started because the hypervisor is not running.   The Hyper-V Virtual Machine Management service is set to Automatic.  I've previously run bcdedit /set hypervisorlaunchtype auto as Administrator. No other VM products like VMWare or Virtualbox is installed.


ALright I have the netbook. I recently did a reset and now I cannot load any apps. It's telling me the internal memory is full and I do not know how to erase things and clear it since it won't let me even download an app to debug/clear cache/clean it.  Who has some helpful suggestions?

Currently, my internal storage is running low on space.    What can I do besides moving applications to the external memory, as to free up more space, but preserve my current applications and avoid uninstalling?  (Some of them won't be moved)


I am relatively new to Ubuntu. I have been trying to run sudo apt-get update only to get a error. This has not happened to me before.  $ sudo apt-get update Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease              Hit:2 http://dl.google.com/linux/chrome/deb stable Release                Hit:3 http://ppa.launchpad.net/jonathonf/python-3.6/ubuntu bionic InRelease Hit:5 http://packages.microsoft.com/repos/vscode stable InRelease              Hit:6 http://ppa.launchpad.net/linuxuprising/java/ubuntu bionic InRelease      Hit:7 http://in.archive.ubuntu.com/ubuntu bionic InRelease                     Hit:8 http://in.archive.ubuntu.com/ubuntu bionic-updates InRelease             Hit:9 http://in.archive.ubuntu.com/ubuntu bionic-backports InRelease           Get:10 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]   Fetched 88.7 kB in 9s (9,888 B/s)                     Traceback (most recent call last):   File "/usr/lib/cnf-update-db", line 8, in <module>     from CommandNotFound.db.creator import DbCreator   File "/usr/lib/python3/dist-packages/CommandNotFound/db/creator.py", line 11, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 24, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'  Original exception was: Traceback (most recent call last):   File "/usr/lib/cnf-update-db", line 8, in <module>     from CommandNotFound.db.creator import DbCreator   File "/usr/lib/python3/dist-packages/CommandNotFound/db/creator.py", line 11, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg' Reading package lists... Done E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi' E: Sub-process returned an error code   What could be causing this problem, and how can I fix it?

I run below command on ubuntu 16.4 :  sudo add-apt-repository ppa:noobslab/apps  of below question:    and get below error:  Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg' Error in sys.excepthook: Traceback (most recent call last):   File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 63, in apport_excepthook     from apport.fileutils import likely_packaged, get_recent_crashes   File "/usr/lib/python3/dist-packages/apport/__init__.py", line 5, in <module>     from apport.report import Report   File "/usr/lib/python3/dist-packages/apport/report.py", line 30, in <module>     import apport.fileutils   File "/usr/lib/python3/dist-packages/apport/fileutils.py", line 23, in <module>     from apport.packaging_impl import impl as packaging   File "/usr/lib/python3/dist-packages/apport/packaging_impl.py", line 23, in <module>     import apt   File "/usr/lib/python3/dist-packages/apt/__init__.py", line 23, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'  Original exception was: Traceback (most recent call last):   File "/usr/bin/add-apt-repository", line 11, in <module>     from softwareproperties.SoftwareProperties import SoftwareProperties, shortcut_handler   File "/usr/lib/python3/dist-packages/softwareproperties/SoftwareProperties.py", line 27, in <module>     import apt_pkg ModuleNotFoundError: No module named 'apt_pkg'   Thanks for help


I am a US permanent resident and I am currently studying abroad in England with a student short-term visa. I went to apply for a Schengen visa to VFS, but I got told that I would need to go back to the States and apply from them (as you can imagine, I cannot do this because it's costly to return). I did some research and found out that I can enter Belgium without a visa if I have a US Refugee Travel Document, which I do have.  I was wondering if there is a way I can travel to other Schengen countries without a visa. Thanks for your assistance--I appreciate it. I am open to any suggestions.

I just want to double check to make sure I won't run into any issues at the border of entry.  I'm a permanent resident of the USA with a green card and I have a travel document issued by the USA (I-571). Will I have any issues traveling around in the Schegen countries?  Do I need a visa? Do I have to pay any fees?


I just changed my project coordinate reference frame to WGS 84 EPSG:4326. Additionally, I set the coordinate reference frame for each layer to EPSG:4326-WGS 84. However, the two layers don't line up. There appears to be some kind of vertical shift going on. Any ideas on what could be causing this discrepancy in their vertical position? In my second image I added the 'OpenStreetMap' layer and changed it's coordinate reference to WGS84, and as you can tell my layers are not lining up with Oklahoma.   How to I make them line up with where they should be?

How do I change the projection of my shapefile using QGIS? The default projection is set to EPSG:3003, I want to change it to WGS84 EPSG:32632. When I do a reprojection or I change projection in the properties mask I don't have the correct result. On the left, I have the plan coordinates but they are not correct for the EPSG shown on the right:


I know how to separate the real and imaginary parts of $\ln z$ and $\arctan z$: $$\begin{align}\ln(x+iy)&=\frac{1}{2}\ln(x^2+y^2)+i\arctan\frac{y}{x}\\ \arctan(x+iy)&=\frac{1}{2}\arctan\frac{2x}{1-x^2-y^2}+\frac{i}{2}\operatorname{artanh}\frac{2y}{1+x^2+y^2}\end{align}$$ and I know how to prove both of these; in particular for the second one we can make use of the fact that $\arctan z=-i\operatorname{artanh}(iz)$. I would now like to know how to separate the real and imaginary parts of $\arccos(x+iy)$; I've thought of using the identity $\arccos(z)=\operatorname{arcosh}(iz)$, but I don't know how to use this, as the argument of the $\ln$ becomes very complicated. Thank you very much for your help.

Beginning with  $$i \cos \left[ \frac{1}{n} \arccos \left( \frac{i}{\epsilon} \right) + \frac{m \pi}{n} \right]$$  where $m,n \in \mathbf{Z}$, $\epsilon >0$, $\epsilon \in \mathbf{R}$ and $i$ is the imaginary unit, I would like to obtain separately the real and imaginary part of the cosine argument:  (1)  $$\frac{1}{n} \arccos \left( \frac{i}{\epsilon} \right) + \frac{m \pi}{n} = x + iy$$  By simply applying the :  (2)  $$\frac{1}{n} \arccos \left( \frac{i}{\epsilon} \right) = \frac{\pi}{2n} + i \frac{1}{n} \ln \left[ \frac{1}{\epsilon} (\sqrt{1 + \epsilon^2} - 1) \right]$$  Similarly, if we apply the  of complex $\arcsin$, we obtain:  $$\arcsin \left( \frac{i}{\epsilon} \right) = -i \ln \left[ \frac{1}{\epsilon} (\sqrt{1 + \epsilon^2} - 1) \right]$$  Remembering (as stated ) that $$\mathrm{arsinh}(z) = -i\arcsin(iz)$$ we obtain  $$\mathrm{arsinh} \left( \frac{1}{\epsilon} \right) = - \ln \left[ \frac{1}{\epsilon} (\sqrt{1 + \epsilon^2} - 1) \right]$$  So we can write  $$x + iy = \frac{m \pi}{n} + \frac{\pi}{2n} + i\frac{1}{n} \ln \left[ \frac{1}{\epsilon} (\sqrt{1 + \epsilon^2} - 1) \right]$$  $$x + iy = \frac{\pi}{2} \left( \frac{2m + 1}{n} \right) - i\frac{1}{n} \mathrm{arsinh} \left( \frac{1}{\epsilon} \right) = \frac{\pi}{2} \left( \frac{2m - 1}{n} \right) - i\frac{1}{n} \mathrm{arsinh} \left( \frac{1}{\epsilon} \right)$$  But the correct result should be  (3)  $$x + iy = \frac{\pi}{2} \left( \frac{2m - 1}{n} \right) + i\frac{1}{n} \mathrm{arsinh} \left( \frac{1}{\epsilon} \right)$$  So, are there any errors? How to obtain (3) from (1)?


My domain is not new at all, in fact I have waited for quite a long time now for Google to show some love. If I do a search for my domain name, it shows the website is listed, but if I try to search for even a year-old post on Google, using my website name too, it never returns it. Instead it says some results have been omitted and asks if those omitted results should be included in the search results.  The following is the message it returns:     In order to show you the most relevant results, we have omitted some   entries very similar to the 8 already displayed. If you like, you can repeat the search with the omitted results included.   Why are my posts are never returned in search results even though I have original and ample content on my website?

This is a general, community wiki  question and answer pair intended to address any questions   concerning the reasons a site or specific site contents do not appear   in search engine results.      If your question was closed as a duplicate of this question and you   feel that the information provided here does not provide a sufficient   answer, please open a discussion on .   My site (or specific pages on my site) is not appearing in search engine results.  Why isn't my content indexed and what can I do about it?


I'm a high school senior interested in pursuing a major in quantitative economics, which I understand is heavily math-intensive. However, as it stands, my academic strengths are more verbal (780 on SAT) than mathematical (630 on SAT). Therefore, I'd much like to increase my skills at math and plan to devote a great deal of my summer studying from a precalculus textbook or two. That's where you good people at Math Stack Exchange come in. I'm hoping some of you could recommend a precalculus level textbook that has the potential to initiate a neophyte such as myself to the math world. Bonus points if you can recommend a textbook that somehow also has applications to economics.   By the way, I actually have already purchased a precalculus level textbook, the University of Chicago School Mathematics Project's Precalculus and Discrete Mathematics, but am of the understanding that it is more of a primer text and thus would be wisely supplemented by something a little more in-depth. This might be helpful to take into consideration as well. I asked this same question at Math Overflow and was told that the site is more reserved for research-level mathematics, and was referred here instead, so I hope this is the right domain for this sort of question. Many thanks for any and all replies.

I'm working my way through Calculus, 9th ed. by Larson and Edwards in independent study. The problem is that many of the exercises and examples use a lot of algebra tricks that are glossed over and assumed knowledge on the part of the student.  Now, when I took precalc in high school I was a total layabout and didn't really absorb many of the finer points as far as some specific topics go (nested absolute value inequalities, for instance) and I'm having a hard time working through many of the exercises. I have no trouble understanding the calculus aspect of the problems, but fail miserably on some of the harder algebraic aspects.   I know I'm not the only one struggling with this, though -- an overarching criticism I've found of this book is that it assumes too much algebra knowledge of undergrad math students and doesn't fully explain any steps.   What I'm really looking for is a precalc-level algebra reference with good examples that I can turn to for specific topics in algebra when I encounter a question I have trouble with.   Can anyone recommend such a thing?    Edit: I'd also like to point out that I have a kindle, so cheaper suggestions for good kindle books are welcome. That's assuming, of course, that kindle is a satisfactory medium for such a thing. I'm not sure.


Why has the question  been protected by Community?     Is that a bug or really community found it very useful?

I noticed  in particular, which has 5 deleted answers on it.  The most recently deleted answer was deleted by a diamond mod 3 minutes prior to the time it was protected by Community ♦  Is there an automated process that causes a question to be protected by Community ♦ instead of a human?  If so, what are the qualifications that it checks for in order apply the protection?  Related:


I have just downloaded a google-font. I want to use it in a specific section of the page. I think I am using the font in an incorrect manner.  .page-header {     font-family: 'Calligraffitti', cursive;     src : url('../fonts/Calligraffitti/Calligraffitti-Regular.ttf'); }   If this is incorrect, could you tell me the correct way of using a font that is not installed on a system?

Is there a way to add some custom font on a website without using images,  or some other graphics?  For example, I was working on a wedding website, and I found a lot of nice fonts for that subject. But I can't find the right way to add that font on the server. And how do I include that font with CSS into the HTML? Is this possible to do without graphics?


I am using pdflatex to document as my program runs. My program prints out some tikz commands in a file, which is compiled by pdflatex offline. In some cases the order of the commmands is not what I like, because the events in my program triggering printing tikz commands occur in the order which is dictated by the program logic, rather than in the order appropriate for preparing the plot. For example, I put a help grid on the figure, but I can find out the size of the grid only when the program is about to terminate, so the help grid will be on the top of other objects; or I am putting some labels on top of a filled rectangle, before the rectangle is drawn. I can work with the figure, but for publication, only for beauty, I need to rearrange manually the order of the objects in the prepared file. Can I use layers for this goal, i.e. I would need three layers, to prepare the plot in a way that my program, in addition to the commands, also names the target layer, and at the end I arrange the three layers, as I want to plot them?

This is an idle question, but neverthless, I think it's interesting.  Does TikZ have a simple way to implement a "z-level" specification. By this, I don't mean 3D drawing, I mean specifying which parts of the picture are on top of what.  So I'd write something like this:  \draw[fill, blue,zlevel=1] (0,0) circle (2); \draw[fill,red,zlevel=2] (0,0) circle (1);   and have the red circle appear on top of the blue one (since it has a higher z-level). I know I could just reverse the order, but I can imagine that being able to specify things this way round might make incremental changes to a TikZ picture in beamer easier by simplifying the overlay specifications...  I suppose you could do something with remember picture, but it seems a "z-level" key would be the easiest solution (from the end user perspective).  Is there anything like this? Is it possible?


I'm working on an exercise about Big O notations and I was wondering if there are any experts here who could help me determine the notation for the following code. so far, I am assuming that it is O(N^2). because a for loop is called in another loop. What do you guys think?  public static Double average(Integer[] values) {     Integer sum = 0;     for (int i = 0; i < values.length; i++) {         sum += values[i];     }     return sum / values.length; } public static IDeque < Integer > slidingAvg(         Stack < Integer > values, int width ) {     IDeque < Integer > window = new ArrayDeque < > (width);     IDeque < Double > averages = new ArrayDeque < > (values.size());     for (int i = 0; i < width; i++) {         window.pushFirst(0);     }     for (int value: values) {         window.pullLast();         window.pushFirst(value);         Integer[] roll = window.toArray(new Integer[0]);         Double average = average(roll);         averages.push(average);     }     return averages; }

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


find . -type f -print0 | xargs -0 ls -ltr | head -n 10 | awk '{print $NF}' | xargs rm   This command is giving me this:  xargs: 'ls' terminated by signal 13   However, it's executing fine. It's supposed to delete the 10 oldest files on the specific folder. Is there something to worry about? Is there a fix?  Server is running BuildRoot.

I have a directory with ~1M files and need to search for particular patterns. I know how to do it for all the files:  find /path/ -exec grep -H -m 1 'pattern' \{\} \;   The full output is not desired (too slow). Several first hits are OK, so I tried to limit number of the lines:  find /path/ -exec grep -H -m 1 'pattern' \{\} \; | head -n 5   This results in 5 lines followed by  find: `grep' terminated by signal 13   and find continues to work. This is well explained . I tried quit action:  find /path/ -exec grep -H -m 1 'pattern' \{\} \; -quit   This outputs only the first match.  Is it possible to limit find output with specific number of results (like providing an argument to quit similar to head -n)?


Then can we say that Int(f(A)) a subset of f(Int(A))? Can we prove or provide counterexample for this claim? The space is (R,d), where d is the absolute value metric, and R is the set of real numbers, f is a continuous function from R to R.  A be a subset of R. If yes, can you extend in for any arbitrary metric spaces I am very new to metric space and topology, so any help will be appreciated.

Suppose consider the space (R,d), where d is the absolute value metric, and f is a continuous function from R to R. Let A be a subset of R. Then is  Cl(f(A)) a subset of f(Cl(A))? Prove or provide counterexample. If yes, can you extend in for any arbitrary metric spaces I am very new to metric space and topology, so any help will be appreciated.


I have read the following example online:     The journey there took three hours. (correct)   (A) The trip took three hours (wrong)   All dictionaries defined a trip as a short distance travel while journey it takes a lot time to achieve, i.e. to travel for a distant area by a vehicle. This already is understood and no question to ask more but I had this example:         (B) We went on a three-week trip to Scotland.   Now my question is: Why do they limit the use of the term (trip) to be for a short-time travel as in A sentence, then it is for three-week tip to _______ as in B?  Here apparently confusion will occur not only to a non-native speaker but to the native speaker as well. I wonder how this duality in English language! I fear and wary off! This is a mistake, the very error to deal with      "A trip to Scotland lasts three weeks" is (correct) but to say: "The trip took three hours" (wrong)!     Another question: Does the trip in the sentence        We went in three-week trip to Scotland   mean going and returning home?

As they always were interchangeable in an article, I just want to know the difference.


I am trying to install the OpenSSH client on my Ubuntu system since I still receive the following error message:   Reading package lists ... Done Building the dependency tree Reading status information ... Done Openssh-client package is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: 'openssh-client' package has no installation candidate   I checked several forums and thought it was a problem updating my system. So I tried to update and I get this message that some packages can not be installed. I do not know what to do. Here is the answer:                   Err http://sunsite.rediris.es xenial Release.gpg   Can not resolve "sunsite.rediris.es" Err http://sunsite.rediris.es xenial-updates Release.gpg   Can not resolve "sunsite.rediris.es" Err http://sunsite.rediris.es xenial-backports Release.gpg   Can not resolve "sunsite.rediris.es" Err http://sunsite.rediris.es xenial-security Release.gpg   Can not resolve "sunsite.rediris.es" W: Can not retrieve http://sunsite.rediris.es/mirror/ubuntu-archive/dists/xenial/InRelease W: The download of some index files failed, they were skipped, or the old ones were used instead.

I'm trying to install KDE 5 on my Ubuntu 16.04 system as per the instructions in , but I'm getting the below error message when running sudo apt-get install kubuntu-desktop.  Is there something I can do to resolve this?  Need to get 682 kB/326 MB of archives. After this operation, 1,272 MB of additional disk space will be used. Do you want to continue? [Y/n] y Err:1 http://ir.archive.ubuntu.com/ubuntu xenial/universe amd64              gtk2-engines-oxygen amd64 1.4.6-1ubuntu1   Temporary failure resolving 'ir.archive.ubuntu.com' Get:2 http://ir.archive.ubuntu.com/ubuntu xenial/universe amd64              libkf5sendlater5 amd64 4:15.12.3-0ubuntu1 [45.2 kB] Get:3 http://ir.archive.ubuntu.com/ubuntu xenial/universe amd64              libthreadweaver4 amd64 4:4.14.16-0ubuntu3 [46.6 kB] Get:4 http://ir.archive.ubuntu.com/ubuntu xenial/universe amd64              libfarstream-0.2-5 amd64 0.2.7-0ubuntu1 [192 kB] Fetched 284 kB in 1min 9s (4,093 B/s)         E: Failed to fetch http://ir.archive.ubuntu.com/ubuntu/pool/universe/g/             gtk2-engines-oxygen/gtk2-engines-oxygen_1.4.6-1ubuntu1_amd64.deb               Temporary failure resolving 'ir.archive.ubuntu.com'  E: Unable to fetch some archives, maybe run apt-get update or              try with --fix-missing?


Most of the abstract algebra books are full of theorems and less examples . Can you please suggest me some sources where I can get the concepts with examples ?

I am taking abstract algebra in this semester. I find that my lecturer didn't provide enough examples for understanding. So I would like to ask what are the recommended books which has lots of solved problems and exercises? The lecturer said in this semester, he will cover group theory, ring theory and a bit of field theory. Which book contains extensive information in these three fields?


I was told that current has a direction but does not follow vector-laws, so it is a scalar quantity. That's okay. I thought it through Kirchoff's junction law: assume two currents joining at 90 deg, but they will not add vectorially, but algebraically.  Now, I am told that current density is a vector quantity. Solving for this, two current densities maybe added at 90 deg or 45 deg they will definitely give same result and will definitely not add vectorially.  So, why is current-density considered as vector?  $$i = j A$$ $i$ is current, $j$ is current-density, and $A$ is the area of cross-section

Current is a scalar $I$ with units of $\mathrm{[J/s]}$. It is defined as $I=\frac{\mathrm{d}Q}{\mathrm{d}t}$. Current density is a vector $\vec{J}$ (with magnitude $J$) with units of $\mathrm{[J/s/m^2]}$. It is current per unit cross-sectional area, and is defined as $\vec{J}=nq\vec{v_d}$ (where $n$ is the number of moving $q$-charges with drift velocity $v_d$).   Why is $I$ defined to not have a direction? Current density $\vec{J}$ is defined as a vector, so why is current $I$ not?  There are many questions about current vs. current density  ... like ,  and , but none answers my question about one being vector and the other being scalar. Is it simply just a definition? It just seems so obvious to define current as a vector too.    of current density is $I = \int \vec{J} \cdot d\vec{A}$. Mathematically, the dot product gives a scalar. But, for me this doesn't give much explanation still, as we could just as well have mathematically defined current as a vector and then used the area in scalar form in an equivalent formula like: $\vec I = \int \vec{J} \cdot dA$.  Is it just a definition without further reason, or is there a point in keeping $I$ in scalar form?


When I try sudo apt command I get the following message:  libopencv-highgui2.4v5 : Depends: libpng12-0 (>= 1.2.13-4) but it is not installed E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).  When I try apt --fix-broken install I get:   libpng12-0 0 upgraded, 1 newly installed, 0 to remove and 74 not upgraded. 5 not fully installed or removed. Need to get 0 B/116 kB of archives. After this operation, 285 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 213917 files and directories currently installed.) Preparing to unpack .../libpng12-0_1.2.54-1ubuntu1_amd64.deb ... Unpacking libpng12-0:amd64 (1.2.54-1ubuntu1) ... dpkg: error processing archive /var/cache/apt/archives/libpng12-0_1.2.54-1ubunt u1_amd64.deb (--unpack):  unable to install new version of '/lib/x86_64-linux-gnu/libpng12.so.0': No suc h file or directory No apport report written because the error message indicates an issue on the lo cal system           Errors were encountered while processing:  /var/cache/apt/archives/libpng12-0_1.2.54-1ubuntu1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)```

For  I need to install libpng12-0 package on the Ubuntu 19.10 system.  I know that it is available .  So I have decided to download this package manually and install it by hand.  On previous Ubuntu versions (such as 18.04 LTS) this trick ends with success, but here on 19.10 it fails in very strange way:   wget http://mirrors.kernel.org/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.54-1ubuntu1.1_amd64.deb sudo apt-get install ./libpng12-0_1.2.54-1ubuntu1.1_amd64.deb  0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/116 kB of archives. After this operation, 285 kB of additional disk space will be used. Get:1 /home/user/libpng12-0_1.2.54-1ubuntu1.1_amd64.deb libpng12-0 amd64 1.2.54-1ubuntu1.1 [116 kB] Selecting previously unselected package libpng12-0:amd64. (Reading database ... 212864 files and directories currently installed.) Preparing to unpack .../libpng12-0_1.2.54-1ubuntu1.1_amd64.deb ... Unpacking libpng12-0:amd64 (1.2.54-1ubuntu1.1) ...  dpkg: error processing archive /home/user/libpng12-0_1.2.54-1ubuntu1.1_amd64.deb (--unpack):  unable to install new version of '/lib/x86_64-linux-gnu/libpng12.so.0': No such file or directory No apport report written because the error message indicates an issue on the local system                                                                                Errors were encountered while processing:  /home/user/libpng12-0_1.2.54-1ubuntu1.1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   What is wrong here? How can I get libpng12-0 installed on Ubuntu 19.10 system?    Note: the same happens on 19.04, but it is near EOL.


I mount C:/, and I create a link from my Ubuntu desktop to Windows desktop. However, when I restart the computer, mount C again, and double click on the link, I get the error message This link cannot be used because its target “/media/me/209A9ACE9A9AA038/Users/me/Desktop” doesn't exist.  So I guess the 209A9ACE9A9AA038 part is some kind of hash that changes every time I mount C. So how can I make a link that will work persistently?   P.S. : I don't need auto-mount, but I want a link that will work whenever I mount the drive.   Thanks for any help!

I'm using ubuntu 14.04 LTS. When I start my pc and click on any bookmark from the file manager it shows this error:   Unable to find the requested file. Please check the spelling and try again. Unhandled error message: Error when getting information for file '/media/angel/DOC/edu': No such file or directory   But when I open DOC drive and again clink on the same bookmark it works properly. Can anybody tell me why is this happening and how to solve this issue?   Edit: Output of lsblk is following: (ubuntu is installed in sda5)  NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 119.2G  0 disk  ├─sda1   8:1    0  91.3G  0 part  ├─sda2   8:2    0     1K  0 part  ├─sda5   8:5    0  24.1G  0 part / └─sda6   8:6    0   3.8G  0 part [SWAP] sdb      8:16   0 465.8G  0 disk  ├─sdb1   8:17   0  93.2G  0 part  ├─sdb2   8:18   0     1K  0 part  ├─sdb5   8:21   0  93.2G  0 part  ├─sdb6   8:22   0  89.3G  0 part  ├─sdb7   8:23   0  93.2G  0 part  ├─sdb8   8:24   0  93.2G  0 part  └─sdb9   8:25   0   3.8G  0 part  sr0     11:0    1  1024M  0 rom     After opening the disk drive the output of lsblk is bellow:   NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 119.2G  0 disk  ├─sda1   8:1    0  91.3G  0 part  ├─sda2   8:2    0     1K  0 part  ├─sda5   8:5    0  24.1G  0 part / └─sda6   8:6    0   3.8G  0 part [SWAP] sdb      8:16   0 465.8G  0 disk  ├─sdb1   8:17   0  93.2G  0 part  ├─sdb2   8:18   0     1K  0 part  ├─sdb5   8:21   0  93.2G  0 part  ├─sdb6   8:22   0  89.3G  0 part /media/angel/DOC ├─sdb7   8:23   0  93.2G  0 part  ├─sdb8   8:24   0  93.2G  0 part  └─sdb9   8:25   0   3.8G  0 part  sr0     11:0    1  1024M  0 rom   The output of sudo blkid gives the following information about sdb6:  /dev/sdb6: LABEL="DOC" UUID="04280A22280A12FA" TYPE="ntfs"


I own a domain name that uses the .co extension and I'm located in France. Someone just advise me to get a .fr domain because it would make my local searches in France better.   I personally thought that Google likes brandnames and would'nt care much about extension but do you have any advice on that? Does anyone has back up numbers to back that up?

Because I'm still living like it's 2008, I run a website with a .in TLD. The website has nothing to do we India and does not target Indian users.  Unfortunately, when I go to Google Webmaster Tools I see that Google have locked my geotargeting status to India:    On the , Google state that:     Sites with country-coded top-level domains (such as .ie) are already associated with a geographic region, in this case Ireland. In this case, you won't be able to specify a geographic location.   This seems implausibly inflexible, so I want to know if there are any sneaky ways of removing auto-geotargeting, or changing it to a more appropriate region?


i have 24gb RAM and 4 core LEMP server for run one application with Websocket PHP/Mysql but the problem is cpu going over 10-18% for just one user  I dont know if server can crash with many users (over 100 in the same time) ?  Im on Debian 7  My config (i add random number)  key_buffer              = 800M max_allowed_packet      = 16M thread_stack            = 192K thread_cache_size       = 8 myisam-recover         = BACKUP max_connections        = 1000 query_cache_limit       = 10M query_cache_size        = 124M log_slow_queries        = /var/log/mysql/mysql-slow.log long_query_time = 1 #log-queries-not-using-indexes   #innodb_read_io_threads=4 #innodb_write_io_threads=8  #To stress the double write buffer #innodb_buffer_pool_load_at_startup=ON #innodb_log_file_size = 32M #Small log files, more page flush #innodb_log_files_in_group=2 #innodb_file_per_table=1 #innodb_log_buffer_size=8M #innodb_flush_method=O_DIRECT #innodb_flush_log_at_trx_commit=0  skip-name-resolve innodb_buffer_pool_size=1G innodb_buffer_pool_size = 3G innodb_thread_concurrency = 12  [mysql] #no-auto-rehash # faster start of mysql but no tab completition   fpm/php.ini  memory_limit = 1024M   memcached.conf  -m 1024   Nginx  worker_processes  3;   This configuration is good or i need to decrease ? Thanks you

This is a  about  Related:      I have a question regarding capacity planning. Can the Server Fault community please help with the following:   What kind of server do I need to handle some number of users? How many users can a server with some specifications handle? Will some server configuration be fast enough for my use case? I'm building a social networking site: what kind of hardware do I need? How much bandwidth do I need for some project? How much bandwidth will some number of users use in some application?


I am fololowing  but this did not work for me .   My start up script is:  #!/bin/bash java -jar AppDemo.jar   My stop script is:  #!/bin/bash #Grabs and kill a process from the pidlist that was the word app  pid=ps aux | grep AppDemo | awk '{print $2}' kill -9 $pid   Myscript for init.d is:  !/bin/bash # AppDemo # # description: Start Jar on system boot   case $1 in     start)     /bin/bash /usr/local/bin/AppDemo-start.sh     ;;     stop)         /bin/bash /usr/local/bin/AppDemo-stop.sh        ;;         restart)         /bin/bash /usr/local/bin/App-Demo.sh         /bin/bash /usr/local/bin/App-Demo.sh        ;;     esac     exit 0   this is now working for me. I don't know what I did wrong can anybody please help?

I have no idea where to start looking. I've been reading about daemons and didn't understand the concept.  More details :   I've been writing a crawler which never stops and crawlers over RSS in the internet. The crawler has been written in java - therefore its a jar right now. I'm an administrator on a machine that has Ubuntu 11.04 . There is some chances for the machine to crash , so I'd like the crawler to run every time you startup the machine. Furthermore, I'd like it to keep running even when i logged out. I'm not sure this is possible, but most of the time I'm logged out, and I still want to it crawl.   Any ideas? Can someone point me in the right direction?  Just looking for the simplest solution.


How can I add a custom form menu link to the administrative menu programmatically?  I am trying to add this form as admin menu link like content, structure and module.

I'm working on a module in Drupal 7. I've added a hook_menu implementation:  $items['admin/config/content/mymodule'] = [   'title'            => 'MyModule',   'description'      => 'Configure MyModule settings.',   'page callback'    => 'mymodule_get_form',   'page arguments'   => ['mymodule_admin_settings'],   'file'             => 'mymodule.admin.inc',   'access arguments' => ['administer mymodule'],   'menu_name'        => 'mymodule', ];   ...and a configure line to mymodule.info:  configure = admin/config/content/mymodule   A Configure link for MyModule now appears the admin/modules page, but how can I also have the module listed on the admin/config page? Or is the admin/config page reserved for only core modules?


Suppose that in an observational study with $N$ units, we have that $X_i$ are our covariates. I have read in several places that in order to calculate an unbiased treatment effect, the $X_i$ are assumed to be iid. I am wondering why this is necessarily the case, and specifically why the independence part is needed. What happens if we do not have:  $$ X_i \overset{iid}{\sim} F $$  for some distribution $F$? What if it is the case that there is a dependency structure for $X_i$ and $X_j$?   The unbiased estimation procedure I am referring to is from . Thank you.

In the textbook "Causal Inference for Statistics" by Rubin and Imbens, the following argument is made on pg. 39:     "In part of this text we view our sample of size N as a random sample   from an infinite super-population. In that case we employ slightly   different formulations of the restric- tions on the assignment   mechanism. Sampling from the super-population generates a joint   sampling distribution on the quadruple of unit-level variables (Yi(0),   Yi(1), Wi, Xi), i = 1, . . . , N. More explicitly, we assume the   (Yi(0), Yi(1), Wi, Xi) are independently and identically distributed   draws from a distribution indexed by a global parameter."   I am wondering why the bolded portion is needed to be assumed. In the context of observational studies what happens if 1) we have dependence, and 2) if the tuple is not jointly identically distributed.   Is this a general assumption that can be relaxed? Where do we really need it? Specifically:  1) What happens if we have dependence?  2) What happens if they are NOT identically distributed?


I am new to Quantum Mechanics, and very much eager to know the secret of it but I don't know from which book I could read. I wonder how the equations are predicted and as well as understand all the physical significance and the concept.I am from India, a student of 11th standard.I have learned calculus but do not know anything about vector space or (Analytical Algebra), in Physics I am well equipped with Mechanics, and other topics of electricity and magnetism.  Please suggest a good book.

I'm really interested in quantum theory and would like to learn all that I can about it. I've followed a few tutorials and read a few books but none satisfied me completely. I'm looking for introductions for beginners which do not depend heavily on linear algebra or calculus, or which provide a soft introduction for the requisite mathematics as they go along.  What are good introductory guides to QM along these lines?


I am currently looking to study Algebraic Geometry. As I am totally new to the subject any reference for books to follow will be helpful, thanks in advance....

I tried to learn Algbraic Geometry through some texts, but by Commutative Algebra, I left the subject; many books give definitions and theorems in Commutative algebra, but do not explain why it is needed.  Can one suggest a good reference to learn this subject geometrically, which would also give ways to translate geometric ideas in algebraic manner, possibly through examples?  Particularly, I am interested in differentials on algebraic curves, Riemann-Roch theorem, various definitions of genus and their equivalences, and mainly groups related to complex algebraic curves such as group of automorphisms, monodromy group etc.


I want to invite my grandfather from Pakistan to Europe (he has positive visa history for Schengen). As you may know most of Pakistanis living in the west reside in the UK and I would like to give him the opportunity to visit our family there.  Can he apply for a UK visa whilst being a non-resident of a Schengen country? We would like to use the service of a certified visa agent here in a Germany because the processing times are much better than in Pakistan.

I am a Zimbabwean passport holder travelling to Denmark. I wanted to confirm if it is possible for me to apply for a UK visa while in Denmark?


I broke my iPhone 4s while I was travelling. So, I put it in my locker. I repaired it yesterday and connected it to iTunes. Unfortunately, My iPhone activated Activation Lock. Only one way to enter my Apple ID is to reset my password but, there is email that i don't know. It looks like g*****@m*****.com. g***** should be my email and I don't remember signing up with this kind of email.  What should I do?

I bought a used iPhone 4.  The previous owner re-set the phone, but did not remove the device from their iCloud.  It is asking me for their iCloud information when I try to set-up the phone.  I don't have contact with the previous owner anymore.  Is there a way to remove the device from their iCloud so I can use a new one?