Today I came to SO and realized that all my hats disappeared! They have been there just yesterday!   What happened? Is Winter Bash over? What a disappointment... I thought it will take place all the winter!
The  page indicates "the hats get put back in their boxes on January 4th". Aside from the pure terror that sentence seems to invoke, I was curious of exactly when this is going to be.  I know that the hats have caused a bit of a time warp at times (for example the starred chat hats). Will this be true of the removal process as well?  Do we get our hats until 23:39 UTC Jan 4th, are they removed at the end of UTC Jan 3rd?
Two identical files; Apache says one is forbidden I am trying to use squared loss to do binary classification on a toy data set. I am using mtcars data set, use mile per gallon and weight to predict transmission type. The plot below shows the two types of transmission type data in different colors, and decision boundary generated by different loss function. The squared loss is $\sum_i (y_i-p_i)^2$ where $y_i$ is the ground truth label (0 or 1) and $p_i$ is the predicted probability $p_i=\text{Logit}^{-1}(\beta^Tx_i)$. In other words, I am replace logistic loss with squared loss in classification setting, other parts are the same. For a toy example with mtcars data, in many cases, I got a model &quot;similar&quot; to logistic regression (see following figure, with random seed 0).  But in somethings (if we do set.seed(1)), squared loss seems not working well.  What is happening here? The optimization does not converge? Logistic loss is easier to optimize comparing to squared loss? Any help would be appreciated.  Code d=mtcars[,c(&quot;am&quot;,&quot;mpg&quot;,&quot;wt&quot;)] plot(d$mpg,d$wt,col=factor(d$am)) lg_fit=glm(am~.,d, family = binomial()) abline(-lg_fit$coefficients[1]/lg_fit$coefficients[3],        -lg_fit$coefficients[2]/lg_fit$coefficients[3]) grid()  # sq loss lossSqOnBinary&lt;-function(x,y,w){   p=plogis(x %*% w)   return(sum((y-p)^2)) }  # this random seed is important for reproducing the problem set.seed(0)  x0=runif(3) x=as.matrix(cbind(1,d[,2:3])) y=d$am opt=optim(x0, lossSqOnBinary, method=&quot;BFGS&quot;, x=x,y=y)  abline(-opt$par[1]/opt$par[3],        -opt$par[2]/opt$par[3], lty=2) legend(25,5,c(&quot;logisitc loss&quot;,&quot;squared loss&quot;), lty=c(1,2)) Vote for Tag Synonyms Directly on the Page Before:  After:   The pros:  Speeds up the tag synonym voting process. Easier to locate (as opposed to navigating to each individual tag wiki page). Encourages users to vote on more than one at a time.  The cons:  Serial up/downvoting. But this really isn't even an issue because, (1) only experienced users can vote on tag synonyms, and (2) more than one vote is required to approve a tag synonym, so the occasional serial up/downvoter won't significantly impact the overall process. "Literally" and "Decimate" misuse Recently I've heard American TV commentators say "[a person] was literally decimated" and "[a Senator] was literally thrown under the bus". In the first case I think the person was not actually 10% killed, but in the second, I believe they meant that 57 members of the US Senate carried #58 onto Constitution Avenue and threw him under a (hopefully moving) bus.  Are usages like these normal or acceptable now? I find them grating, myself. File changed listener in Java What is wrong in this proof: That $\mathbb{R}$ has measure zero Consider $\mathbb{Q}$ which is countable, we may enumerate $\mathbb{Q}=\{q_1, q_2, \dots\}$. For each rational number $q_k$, cover it by an open interval $I_k$ centered at $q_k$ with radius $\epsilon/2^k$.  The total length of the intervals is a geometric progression that sums up to $\epsilon$.  Each real number is arbitrarily close to a rational number since $\mathbb{Q}$ is dense in $\mathbb{R}$. Thus, each real number is in one of the open intervals.  Thus the entire real line is covered by the union of the $I_k$, thus $\mathbb{R}$ is a null set with measure zero.  Clearly there is something wrong in the above proof, however I am not sure where is it?  Thanks for any help. What TV show has kids entering a video game of some sort? I've been searching the entire Internet for this show about 4 teenagers that enter a video game world where they have to fight monsters that looked like insects. Every time they had to enter the world, they'd go down in the sewers and one of the guys had a skateboard, a girl had a scooter and that's what I can remember. There was also one guy that always stayed behind to check their "health" in the game and pull them out in case they took too much damage to avoid them dying inside the game. I don't know if it was animated or not so there's not much to go on at all but hopefully someone might know what show it is? Get text from pressed button Pointwise convergent and total variation Is it possible to connect two monitors on a laptop, one through HDMI and the other through DisplayPort? For example the Alienware m17x offers 3 connections, HDMI, DisplayPort, and VGA. Is it possible to connect two independent external monitors, one through the DisplayPort and one through the HDMI port? I'd like to highlight paragraphs such that the highlight color appears as one whole rectangle underlying the entire paragraph. I have looked around but nothing gives me the desired effect so far.  For example \fcolorbox{} from xcolor cannot highlight an entire paragraph; \hl{} from soul leaves out spacings between lines uncolored.  I am wondering how I can do this? Consider repeated measures ANOVA (RM-ANOVA) with one within-subject factor A and several measurements per subject for each level of A.  It is closely related to two-way ANOVA with two factors: A and subject. They use identical decomposition of the sum of squares into four parts: A, subject, A⋅subject, and residual. However, two-way ANOVA tests the effect of A by comparing SS of A with the residual SS, while RM-ANOVA tests the effect of A by comparing SS of A with the A$\cdot$subject interaction SS.   Why the difference?    Does this difference automatically follow from the repeated-measures structure of the data, or is it some convention?  Does this difference between two-way ANOVA and RM-ANOVA correspond to testing two different nulls? If so, what exactly are they and why would we use different nulls in these two cases? Two-way ANOVA's test can be understood as an F-test between two nested models: the full model, and the model without A. Can RM-ANOVA be understood in a similar way?   (If there is only one measurement per subject for each level of A, then the distinction sort of disappears because A$\cdot$subject and residual variation cannot be disentangled: )    Demonstration  I will use toy data d2 generated in . The same webpage shows correct syntax for RM-ANOVA.  # Discarding between-subject factors and leaving only one within-subject factor d = d2[d2$Xb1=='CG' &amp; d2$Xb2 == 'f', c(1,4,6)]   (See reproducible version .) Data look like that:       id Xw1     Y 1    s1   A  28.6 2    s1   A  96.6 3    s1   A  64.8 4    s1   B 107.5 5    s1   B  77.3 6    s1   B 120.9 7    s1   C 141.2 8    s1   C 124.1 9    s1   C  88.0 10   s2   A  86.7 ...   Here is two-way ANOVA: summary(aov(Y ~ Xw1*id, d))               Df Sum Sq Mean Sq F value   Pr(&gt;F)     Xw1           2  95274   47637  16.789 3.73e-07 *** id           19  31359    1650   0.582    0.913     Xw1:id       38  71151    1872   0.660    0.929     Residuals   120 340490    2837                    Here is RM-ANOVA: summary(aov(Y ~ Xw1 + Error(id/Xw1), d))  Error: id           Df Sum Sq Mean Sq F value Pr(&gt;F) Residuals 19  31359    1650                 Error: id:Xw1           Df Sum Sq Mean Sq F value   Pr(&gt;F)     Xw1        2  95274   47637   25.44 9.73e-08 *** Residuals 38  71151    1872                       Error: Within            Df Sum Sq Mean Sq F value Pr(&gt;F) Residuals 120 340490    2837               Note the identical SS decomposition, but two-way ANOVA tests Xw1 against the residual, while RM-ANOVA tests Xw1 against the Xw1:id interaction.  Why?  This question is related to . If we try using Error(id) instead of Error(id/Xw1) in the example above, then Xw1 will get tested against Xw1:id interaction lumped together with the residual variation.  (The same issue arises in factorial RM-ANOVA with multiple within-subject factors, where each factor or interaction is tested against its own "error term" aka "error stratum". These error strata are always given by the corresponding interaction with the block/plot/subject variable id.) Proof of the formula $1+x+x^2+x^3+ \cdots +x^n =\frac{x^{n+1}-1}{x-1}$ Possible Duplicate:          Proof to the formula  $$1+x+x^2+x^3+\cdots+x^n = \frac{x^{n+1}-1}{x-1}.$$ 401k withdrawal abroad and state taxation? From what I know about 401k's, when it's time to retire, we take our 401k money and pay federal and state tax. Some states don't have taxes on 401k's — Florida is a good example. So many people move to Florida for a retirement, not to pay taxes (that's why people call it heaven's waiting room). The question is - how does it work if a US citizen permanently moves to another country for a retirement (retaining citizenship, but not living in any of the US states)? Are there any state taxes? If yes, then why? What features of Mavericks are beneficial to you? This question serves to share and collect the enhancements that make a large difference to how you use your Mac.   Please post one feature per answer. Please also check to see if your answer has already been posted - duplicate answers will be deleted. To search answers for this question use  (directly from the question page) in addition to your search terms in the search box in the upper right hand corner of this page.  The best answers will not only list a feature, but provide details on how to configure that feature, and provide an image of how to use the feature to be more efficient or effective with Mavericks. Double dual mappings String representation of an Enum I have the following enumeration:  public enum AuthenticationMethod {     FORMS = 1,     WINDOWSAUTHENTICATION = 2,     SINGLESIGNON = 3 }   The problem however is that I need the word "FORMS" when I ask for AuthenticationMethod.FORMS and not the id 1.  I have found the following solution for this problem ():  First I need to create a custom attribute called "StringValue":  public class StringValue : System.Attribute {     private readonly string _value;      public StringValue(string value)     {         _value = value;     }      public string Value     {         get { return _value; }     }  }   Then I can add this attribute to my enumerator:  public enum AuthenticationMethod {     [StringValue("FORMS")]     FORMS = 1,     [StringValue("WINDOWS")]     WINDOWSAUTHENTICATION = 2,     [StringValue("SSO")]     SINGLESIGNON = 3 }   And of course I need something to retrieve that StringValue:  public static class StringEnum {     public static string GetStringValue(Enum value)     {         string output = null;         Type type = value.GetType();          //Check first in our cached results...          //Look for our 'StringValueAttribute'           //in the field's custom attributes          FieldInfo fi = type.GetField(value.ToString());         StringValue[] attrs =            fi.GetCustomAttributes(typeof(StringValue),                                    false) as StringValue[];         if (attrs.Length &gt; 0)         {             output = attrs[0].Value;         }          return output;     } }   Good now I've got the tools to get a string value for an enumerator. I can then use it like this:  string valueOfAuthenticationMethod = StringEnum.GetStringValue(AuthenticationMethod.FORMS);   Okay now all of these work like a charm but I find it a whole lot of work. I was wondering if there is a better solution for this.  I also tried something with a dictionary and static properties but that wasn't better either. I own a Nikon D40X and just the kit lens and I'm considering buying either a macro lens or some extension tubes.  I don't necessarily want to do true 1:1 macro, just some close ups of bugs, fungi and flowers. I was wondering, why there are passport checks at the check-in counter, Immigration and even at the gate?    For example, I was at Istanbul flying to either UK or US. There's a security check at the check-in counter asking a bunch of questions about my immigration status - even more than the Immigration officer at the border. Also, at the gate, there's also Security officer checking my immigration status and passport asking the same questions.    I thought that would be the responsibility of an Immigration officer rather than some third party company?   The thing I'm curious the most is they don't even know which countries this passport can go to with or without visa. They have to go back to the counter and check with the system which takes a long time. I was wondering why they hire these kind of companies to slow down the process? Laplace transform of $1/t$