I have just installed Lubuntu on a laptop.  I was trying to install it alongside Windows and therefore chose the option for Local Volume control (I think that is correct) and expected that when I booted up I would be presented with a choice between Lubuntu and Windows. But I am not getting a choice.  It goes straight into Lubuntu.  So have I lost my windows files forever or is there a way to get back in Windows and recover my files? Thank you. SJF
I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?
Euclidean distance vs Squared How to approach the modeling of duct work, piping, wiring? Finite subgroups of the multiplicative group of a field are cyclic In Grove's book Algebra, Proposition 3.7 at page 94 is the following     If $G$ is a finite subgroup of the multiplicative group $F^*$ of a field $F$,   then $G$ is cyclic.   He starts the proof by saying "Since $G$ is the direct product of its Sylow subgroups ...". But this is only true if the Sylow subgroups of $G$ are all normal. How do we know this? How to avoid interference in wireless communication? I am working on wireless communication system. We are using around 10 pairs of transmitter and receivers. We are using atmega16 microcontroller for encoding and decoding by USART ports.  Now we are able to transmit the data and receive the same in the receiver end, but there is a major problem, when we are finding the 2 transmitter data coming at the same time. The receiver is unable to get it due to interference.  Suppose one transmitter sends "SENDA" at the meanwhile another transmitter sends "GETTS", at that time the receiver can not receive proper data. As all the transmitters and receivers are working in same frequency, so this interference is occurring. How can I resolve this issue? Specifying latest revision of a particular branch with bower Where can I find other RPG players? I'd really like to learn how to play pen-and-paper RPGs.  I know that it takes a few players to actually sit down and play, but I'm not at all sure where to find more gamers.  How do I find existing groups to join? Or, are there any resources online that may help me find existing RPG groups or players? Number of connected components of the complement of a compact Let $X$ be a connected, locally compact space and let $K$ be a compact subset of $X$. Is the number of connected components of the complement $X\setminus K$ finite? If it is not, are there some hypotheses over $X$ for finiteness of connected components? Move incoming Outlook emails to folder containing previous conversation I file email conversations in various folders. But every new email in that conversation goes to inbox, so I have to manually move it to the folder that contains the rest of the conversation. Is there a way for Outlook to do this automatically with all new emails?  What I want: Outlook will do the following automatically as long as it's running:   For all unread emails in inbox... ...if email is not the first in the conversation, search for folders where that conversation is stored. If found, move the new unread email to the first* folder it finds (except for Inbox, Trash, or Sent). Optionally: If there is more than one folder containing messages in the same conversation, then do nothing.   **If there is more than one folder containing messages in the same conversation, then do nothing*. (This extra rule is not necessary if it complicates the solution too much)  Thanks! Why do we use ./filename to execute a file in linux?  Why not just enter it like other commands gcc, ls etc... Why use apparently meaningless do-while and if-else statements in macros? In many C/C++ macros I'm seeing the code of the macro wrapped in what seems like a meaningless do while loop.  Here are examples.  #define FOO(X) do { f(X); g(X); } while (0) #define FOO(X) if (1) { f(X); g(X); } else   I can't see what the do while is doing.  Why not just write this without it?  #define FOO(X) f(X); g(X) JSON and escaped double quote I'm currently making a callout to a 3rd party vendor and I'm getting a huge response. What is currently messing me up is this section:   "MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false   As you can see here, the portion at the end of the Description value is ended with backslash double quote. If I attempt to parse this via the JSONParser I get an exception. Does anyone have an recommendations on how to resolve this?  Exception Message:  System.JSONException: Unexpected character ('"' (code 34)): was expecting comma to separate OBJECT entries at [line:1, column:3699]  Updated with sample Code   public class ResponseWrapper{     // fields from JSON to auto map     public Integer messageSeq;     public String Description;     public String messageTS;     public Integer messageLevel;     public Boolean isSystemMessage;     // parsing fields     private ResponseWrapper theResponse;     private JSONParser parser;      public void parse(String jsonString){         parser = JSON.createParser(jsonString);         parseJSON();     }      private void parseJSON(){            while (parser.nextToken() != null) {             if (parser.getCurrentToken() == JSONToken.START_OBJECT) {                 theResponse = (ResponseWrapper)parser.readValueAs(ResponseWrapper.class);                            }         }     } }  String responseString = '{"MessageSeq":13,"Description":"config file: config-qa1.txt\"","MessageTS":"2014-02-17T14:46:58","MessageLevel":4,"IsSystemMessage":false}'; system.debug('\n\nBEFORE\n' + responseString); ****Place code in here to test such as ReplaceALL*** ResponseWrapper parser = new ResponseWrapper(); parser.parse(responseString); Is it possible to accept the alternative hypothesis? I'm aware of several related questions here (e.g., , ) but I don't know the definitive answer for my question below.  Suppose a hypothesis test where we want to test whether a coin is fair or not. We have two hypotheses:  $H_0: p(head)=0.5$  $H_1: p(head)\neq0.5$  Suppose we use 5% significance level, there are two possible cases:   When we obtain the data and find that the p-value is less than 0.05, we say "With significance level 5%, we reject $H_0$."  p-value is greater than 0.05, then we say "With 5% significance level, we cannot reject $H_0$."   My question is:      In case 1, is it correct to say "we accept $H_1$"?   Intuitively, and from what I have learned in the past, I feel that "accepting" anything as a result of hypothesis testing is always incorrect. On the other hand, in this case, since the union on $H_0$ of $H_1$ covers the whole "space", "reject $H_0$" and "accepting $H_1$" look exactly the same to me. On another thought, I can also think of the following idea, which says it is incorrect to say "we accept $H_1$":     We have an evidence strong enough to believe that $H_0$ is not true, but we may not have an evidence strong enough to believe that $H_1$ is true. Therefore, "rejecting $H_0$" does not automatically imply "accepting $H_1$"   So, what is the right answer? I have several std::vector, all of the same length. I want to sort one of these vectors, and apply the same transformation to all of the other vectors.  Is there a neat way of doing this? (preferably using the STL or Boost)?  Some of the vectors hold ints and some of them std::strings.  Pseudo code:  std::vector&lt;int&gt; Index = { 3, 1, 2 }; std::vector&lt;std::string&gt; Values = { "Third", "First", "Second" };  Transformation = sort(Index); Index is now { 1, 2, 3};  ... magic happens as Transformation is applied to Values ... Values are now { "First", "Second", "Third" }; How to make a persistent live Ubuntu USB with more than 4GB I want to make a persistent live Ubuntu USB drive with more than 4GB of storage.   I know there is an option of installing directly on the drive but I don't want to do this as it will restrict the drive from working on different computers.   One option is to make an additional partition with extra space but if I do this how can I get newly installed software to be stored on this partition? Repeated error  I have been repeatedly encountering the following error when my laptop freezes. It may occur multiple times during the day, and should take several minutes to recover.  Source Windows  Summary Hardware error  Date ‎11/‎1/‎2018 10:11 AM  Status Not reported  Description A problem with your hardware caused Windows to stop working correctly.  Problem signature Problem Event Name: LiveKernelEvent Code:   144 Parameter 1:    3003 Parameter 2:    ffffad8c0b1a75c8 Parameter 3:    40010002 Parameter 4:    0 OS version: 10_0_17134 Service Pack:   0_0 Product:    256_1 OS Version: 10.0.17134.2.0.0.256.48 Locale ID:  1033   More details  Per my best reflection, the hardware error occurs when I am using the laptop on its docking station. Here is what I observe:   While using the laptop as normal, the "freeze" will occur and I can hardly operate the laptop: mouse cursor won't move continuously and Alt+Tab won't be able to switch across two windows. Shortly after (usually several minutes), things will go back to normal. Upon inspecting through the Performance tab in Task Manager, there had been no spike in anything, be it CPU, Memory or Disk. When I open the View reliability history tool, I will find another entry of Windows Hardware Error   Machine specification:   Thinkpad T480, i7-8650U (newly replaced module thanks to the manufacture)   With the same pair of docking stations, an older unit of T480 has had exactly the same problem.  Docking station: . Same issue has occurred on two identical docks with  slightly different monitors and accessories. OS specification: OS build 17134.376. Most recent collection of "reliability report":    Possible solutions   First, I would like to learn what exactly went wrong, hardware-wise: the manufacturer's support team did not bother too much with the precise error messages, and have ordered me to reinstall the Windows OS up to 5 times in total. [This is what they called "debugging".]   Please advise if you can decipher the recurrent "Hardware error".   Secondly, I will try to push the manufacturer to replace the docking stations, and see if the same "freezing problem' persists. Subgroup of $\mathbb{R}$ either dense or has a least positive element? Can someone explain me this  please I am a bit confused?  It's from a texbook I am reading (block cipher companion)  it says that:      each weak key has  $2^{32}$ fixed points $m$ where $\operatorname{DES}_w(m) = m$ ( $w$ is a DES weak key). In other words encrypting a fixed point gives exactly the same point. To see this consider the $2^{32}$ ciphertexts after 8 rounds of encryption for which the two 32 bit halves are equal. For a weak  DES key, the round keys of the eighth and ninth rounds are equal. Thus the intermediate texts after seven rounds and after nine rounds of encryption will be equal. Since the round keys of the 7th and the 10th rounds are equal, the intermediate texts after 6 rounds and after 10 rounds of encryption will be equal. Continuing like this it follows that the plaintext will be equal to the ciphertext.    Now did not quite get :   Why are there $2^{32}$ fixed points?  And why after the eighth round of encryption the two halves must be equal? What does the author mean by the intermediate texts exactly? And how are they being equal?   P.S.: This question is not asking for what the weak keys are. I am asking for "fixed points" not exactly weak keys. For this reason I think it is not a duplicate of any other question. There is one similar question to what I've asked for which I have checked and saw that no satisfactory answer has been given there either.  Here is the similar question with no proper answers: Multiple logistic regression power analysis What is the meaning of ./ before a given path? Interpretation of mean absolute scaled error (MASE)