I've worked with observations as vectors with both continuous and categorical variables. In both cases one can use dimensionality reduction techniques such as PCA (in the latter case through Correspondence Analysis).  This has been very useful for me to draw the observations in the plane (by taking the 2 first components).  But I don't know an equivalent method for drawing points from a distance matrix. I know the result won't preserve all distances in general, but just an approximation is fine (as when removing components from PCA). To put a concrete example, words with "edit distance" (there are variations which are true metrics).  Is it reasonable to just do PCA on the distance matrix itself and draw the first 2 components? Or is there a better way?  Bonus: in the best case scenario, I would like to work without evaluating my distance function for all pairs (I've read there are space partitioning data structures, but haven't tried them; this is related to the efficient solution to kNN I believe).
How are PCA and classical MDS different? How about MDS versus nonmetric MDS? Is there a time when you would prefer one over the other? How do the interpretations differ?
How do I disable "Link Preview" in Chrome? Dirac delta function as a limit of sinc function I understand what the Chinese remainder theorem is. However I am not sure how to apply it to my question. Can someone explain please? We have a SBS 2011 server with 16GB memory that runs Exchange, WSUS and File Sharing for approx 20 users. The server also gives 2GB memory to a virtual machine running in Hyper-V so 14GB left for the rest.  When the server first boots Store.exe consumes about 500MB memory, WSUS and IIS consume some as well, but we generally are only at 60% capacity. During the course of the working day Store.exe consumes 8GB memory and the server sits at approx 97% capacity.  This makes using the server very slow, logging on via RDP is slow, general server admin is slowed down.  Is this normal? I have read that Exchange will consume lots of memory that it does not neccessarily need and then releases it back to other applications that need it. I have also checked that all mailboxes are opened in cached mode. We do have some external uses who connect via Outlook Anywhere or OWA.  If it's deemed to be "normal" is there some way I can restrict it using ALL available memory and leave a little bit for SBS to use for server admin? I have seen some articles regarding setting a high and low memory flag but rumours that this does not work with update rollup 5 which we have installed.  Am I expecting a single server to do to much with only 14GB memory?  Thanks How to make a water vortex I'm very new to Blender and I'm trying to make a water vortex like this.(may be not the easyest first project for a newbie)     I watched several tutorial on liquids particle etc but I'm not sure what is the best aproach. What I tried  until now:   I made a particle system with a vortex force field. It looks good, but I'm not able to add the right material.      I played around with the fluid physics, the water looks good but if I add a vortex force field it does nothing.   I would be very grateful if somebody could point me in the right direction because I'm definitely stocked. Does one wing of fly contain harmful microbes and the other contain only antibodies? There was  study but the conclusion and it's source's relability seemed a bit off. How come a house flies one wing contain all microbe and the other don't. Maximizing expected value of coin reveal game I was asked this question today in an interview and am still not sure of the answer. The question is as follows.   Part one:  Say I have flipped 100 coins already and they are hidden to you. Now I reveal these coins one by one and you are to guess if it is heads or tails before I reveal the coin. If you get it correct, you get $\$1$. If you get it incorrect, you get $\$0$. I will allow you to ask me one yes or no question about the sequence for free. What will it be to maximize your profit?  My approach for this part of the problem was to ask if there were more heads than tails. If they say yes, I will just guess all heads otherwise I just guess all tails. I know the expected value for this should be greater than 50 but is it possible to calculate the exact value for this? If so, how would you do it?   Part two: Same scenario as before but now I will charge for a question. I will allow you to ask me any amount of yes or no questions as I go through this process for $\$1$. What is your strategy to maximize your profit?  I was not sure about the answer to this part of the question. Would the best option be to guess randomly? I think the expected value of this should be 50. I am not sure about the expected value of part one but if it is greater than 51, I think I could also use that approach. Anyone have a good idea for this part? Bonferroni adjustment in SPSS - what does it do? I'm probably being a bit simplistic here, but from what I understand the Bonferroni post hoc test is simply when we adjust the alpha to account for inflated error when several post hoc tests are conducted. You divide the alpha by number of tests. So what exactly does SPSS do when we click the button for Bonferroni?   Shouldn't the dividing of alpha be done by us in interpreting the result, e.g. if we do 10 post hoc tests our alpha criterion should be .005 so if the p value is .012 then it is not significant, but SPSS hasn't done anything there, we have just changed our interpretation. So what exactly is it adjusting? How do I suspend a whole process (like the Process Explorer does when I click Suspend) in C#.  I'm starting the Process with Process.Start, and on a certain event, I want to suspend the process to be able to do some investigation on a "snapshot" of it. Are there names for consonant-shifts when suffixes are added? "The ticket is printing" vs "...is being printed" You're standing in front of a ticket vending machine and it says "The ticket is printing". Is that correct or should it be "The ticket is being printed"?  EDIT:  If both are correct, which one should be preferred or is more common? ASP.NET MVC Default Project Structure and the Scripts Folder From what I understood, cardinal numbers are defined as:  $\aleph_0$ = the cardinality of $\mathbb{N}$ $\aleph_{n+1}$ = is the least cardinal number greater than $\aleph_n$  The continuum hypothesis states that the cardinality of $\mathbb{R}$ is  $\aleph_1$. I more or less understand this cannot be proven (does not follow from ZFC).  However, can it be proven dat there in fact is a 'least cardinal number' greater than $\aleph_0$?  Is it possible that there are sets with cardinality $\aleph_{1/2}$, $\aleph_{1/3}$, et cetera, so to speak?  Or expressed differently: is it possible that for every set A with cardinality CA > $\aleph_0$, there exists another set B with cardinality CB where CA > CB > $\aleph_0$? With arrays, why is it the case that a[5] == 5[a]? What's the difference between  and ,  and ? What's the difference between &lt;b&gt; and &lt;strong&gt;, &lt;i&gt; and &lt;em&gt; in HTML/XHTML? When should you use each? Most of you if not everybody will agree that the stronger the gravitational pull, the faster an object will fall. For example, on a planet with 50 times the gravity of Earth, any object will hit the ground on that planet much quicker than it would on Earth. So taking all of these into the equation, does it mean that at a blackhole, an object will fall at an infinite speed because of the infinitely strong gravitational pull of the blackhole? Creating vimrc breaks vim I'm currently logged into a server via ssh with ssh -Y and running a tmux session. If I start vim and run :colorscheme elflord the color scheme is changed. (Although the colors are not exactly what I would expect although they are I think 256 color. If I create a ~/.vimrc file and put a single line colorscheme elflord  in it then when I run vim it shows no color (just white text) and I cannot change the color with the :colorscheme command. How to list of all the tables defined for the database when using active record? How do I get a list of all the tables defined for the database when using active record? Fiction novel or movie about sentient dinosaurs Block specific URL on web browsers I want to block certain URLs on browsers. I don't want to block whole site. For example, I want to block , but not whole  domain. Is there any way I can do it?