Intuitive understanding of Extreme Learning Machine I have read the description of the ELM in , but a lot of it goes over my head.   What is a less mathematical, more intuitive understanding of ELM?
Extreme learning machine: what's it all about? I've been thinking about, implementing and using the Extreme Learning Machine (ELM) paradigm for more than a year now, and the longer I do, the more I doubt that it is really a good thing. My opinion, however, seems to be in contrast with scientific community where -- when using citations and new publications as a measure -- it seems to be a hot topic.  The ELM has been introduced by  around 2003. The underlying idea is rather simple: start with a 2-layer artificial neural network and randomly assign the coefficients in the first layer. This, one transforms the non-linear optimization problem which is usually handled via backpropagation into a simple linear regression problem. More detailed, for $\mathbf x \in \mathbb R^D$, the model is  $$ f(\mathbf x) = \sum_{i=1}^{N_\text{hidden}} w_i  \, \sigma\left(v_{i0} + \sum_{k=1}^{D} v_{ik} x_k \right)\,.$$  Now, only the $w_i$ are adjusted (in order to minimize squared-error-loss), whereas the $v_{ik}$'s are all chosen randomly. As a compensation for the loss in degrees-of-freedom, the usual suggestion is to use a rather large number of hidden nodes (i.e. free parameters $w_i$).  From another perspective (not the one usually promoted in the literature, which comes from the neural network side), the whole procedure is simply linear regression, but one where you choose your basis functions $\phi$ randomly, for example  $$ \phi_i(\mathbf x) = \sigma\left(v_{i0} + \sum_{k=1}^{D} v_{ik} x_k \right)\,.$$  (Many other choices beside the sigmoid are possible for the random functions. For instance, the same principle has also been applied using radial basis functions.)  From this viewpoint, the whole method becomes almost too simplistic, and this is also the point where I start to doubt that the method is really a good one (... whereas its scientific marketing certainly is). So, here are my questions:   The idea to raster the input space using random basis functions is, in my opinion, good for low dimensions. In high dimensions, I think it is just not possible to find a good choice using random selection with a reasonable number of basisfunctions. Therefore, does the ELM degrade in high-dimensions (due to the curse of dimensionality)? Do you know of experimental results supporting/contradicting this opinion? In the linked paper there is only one 27-dimensional regression data set (PYRIM) where the method performs similar to SVMs (whereas I would rather like to see a comparison to a backpropagation ANN) More generally, I would like to here your comments about the ELM method.
How to change LCD brightness from command line (or via script)? To work around  (changing LCD brightness via hotkeys impossible), I'd like to have one command line query for increasing and one for reducing the brightness of my LCD. I could then map a hotkey to each one of this queries.  The problem is: I don't know how to increase and reduce the LCD brightness on the command line. Do you? This comes up every time I login, how do I remove this or fix it.  Thanks. show that every continuous real-valued function defined on $S_{\mathbb{\Omega}}$ is eventually constant File changed listener in Java I'd like to be notified when a file has been changed in the file system. I have found nothing but a thread that polls the lastModified File property and clearly this solution is not optimal. How to make text file created in Ubuntu compatible with Windows Notepad? Sometime I have to use the text files created in Ubuntu, using editors, in Windows editors. So basically when ever I create a text file in Ubuntu I append the extension .txt, and it does make the file open in Windows very easily.  But the actual problem is the text files created in Ubuntu are so difficult to understand (read) when opened in Windows' Notepad. No matter how many lines have been used, all the lines appear in the same one line.  Is there a easy way to save the text files in Ubuntu's basic editors so that it can be seen exactly the same in Windows' notepad? Isomorphism between $\mathfrak o(4,\mathbb R)$ and $\mathfrak o (3,\mathbb R) \oplus\mathfrak o (3,\mathbb R) $ I'm trying to find the derivative of $\sin^{-1}(x)$. I know the steps that lead to $\frac{1}{\sqrt{1-x^2}}$, however I don't understand why the following reasoning leads to a wrong answer.  Because  $$\frac{d}{dx}f^{-1}(x) = \frac{1}{f'(f^{-1}(x))} $$  If we plug in for $f(x) = \sin(x)$, and because $\frac{d}{dx}\sin(x) = \cos(x)$ we get  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\sin^{-1}(x))} $$  Since $\sin(x) = \cos(x-\frac{\pi}{2})$, we can state that $\sin^{-1}(x) = \cos^{-1}(x-\frac{\pi}{2})$. (I suspect this is what is wrong)  Thus,  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\cos^{-1}(x-\frac{\pi}{2}))}$$  Then, by the definition of inverse function, we have  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{x - \frac{\pi}{2}}$$ Subtracting even and odd binomial coefficients? Suppose you want to ask someone to do something, say to tell you the way to a station. Which is more polite, "Would you tell me the way to the station?" or "Could you tell me the way to the station?"? To be short, I want to copy a folder to a location /usr/share/screenlets/.... in Ubuntu 10.04 system. I tried by logging in as root from terminal giving su.   I even changed my user account type to ADMINISTRATOR; Yet, no use. PASTE option in the context menu's list in the folder /usr/share/... is INACTIVE.  How can I copy those files? Polynomial ring $R[X] $ has zero Jacobson radical, for $R$ a domain I have a problem regarding alignment for my equations.  This dummy program shows the problem:  \documentclass{article} \usepackage{amsmath} \begin{document}  \begin{enumerate}     \item First do this     \begin{align}     c^2 &amp;= a^2 + b^2     \end{align}      \item Then do this      \begin{align}     variable &amp;= c^2     \end{align} \end{enumerate}  \end{document}     I would like the = to be aligned under each other, but still be able to list them inside the enumerate.  Any suggestions? Problem with a sequence with multiple integrals how to get the selected date in jquery I have Ubuntu on my MacBook 2007 with a Spanish keyboard, on MacOS the @-sign was typed using Alt (Option) + 2, but on Ubuntu I have no idea. I have to copy and paste it every time. How do I type an at sign? How to change Function (Fn) Key behavior on wireless Logitech keyboard I do have a wireless Logitech K750 keyboard (silver Mac version) connected to a Lenovo ThinkPad (via the unifying USB receiver, together with a wireless Logitech mouse M705) and currently running Ubuntu 12.04.  By default the F-keys are mapped as multimedia/function keys, e.g. Play  /Pause. As I don't use them very often, I want the F-keys to behave like the "real" F-keys (F1-F12). How can I do that?  I know there is an option in the BIOS settings, but this only toggles the built-in keyboard of the notebook, not on my wireless keyboard.  I know there is a way to change this for the Apple wireless keyboard (), but there is no "parameters" directory in /sys/module/hid_logitech_dj/.  Any ideas? Or is there maybe a way to do this in a later Ubuntu version (13.04)?  UPDATE:  lsusb -d 046d: shows Bus 002 Device 005: ID 046d:c52b Logitech, Inc. Unifying Receiver  UPDATE 2: Thanks a lot for your help Lekensteyn. Finally  works just fine. In the "Known Issues" of Solaar it says that it does not work with the Nano Receiver. But I have one and it works just fine. Just don't forget to read the installation instructions and run the rules.d/install.sh script. It also recognized my M705 Mouse. Integrate $e^{ax}\sin(bx)?$ Is there a general formula for finding the primitive of $$e^{ax}\sin(bx)?$$  I've done this manually with $a=9$ and $b=4$ using Euler's formulas. But it takes a bit of time. Is there a pattern here? Knowing which java.exe process to kill on a windows machine When a java based application starts to misbehave on a windows machine, you want to be able to kill the process in the task manager if you can't quit the application normally. Most of the time, there's more than one java based application running on my machine. Is there a better way than just randomly killing java.exe processes in hope that you'll hit the correct application eventually?  EDIT: Thank you to all the people who pointed me to Sysinternal's Process Explorer - Exactly what I'm looking for! about://(null) popup? I encountered a popup similar to this one this morning while checking the weather report at  in Safari, though I have not been able to reproduce it.  The title is "about://(null)" and the text "Why you no play Candy Crush!!"  The popup occurred twice.  I tapped Cancel both times.  I suspect the source of this is rogue JavaScript in an ad network, judging from the fact that the screenshot below shows it in an ad-supported application, and when I saw it, I was on an ad-supported website.  My phone is not jailbroken.  I'm wondering if anyone is able to identify the source of the popup definitively.  Speculation is running rampant on Apple's support communities and elsewhere, from push notifications (delete Facebook and all your games!) to carrier notifications (which don't work on iPod Touches…), and my gut tells me little of it is helpful.  But I could also be very wrong.  (This is not my screenshot; it comes from .)    UPDATE 1: The Candy Crush people have this to say, but I'm not (yet) convinced there's actually something installed that is to blame:   UPDATE 2: Just reproduced it in the iOS Simulator while clicking around woodtv.com, but I'm not sure how to track it down further from here. How to encrypt folders (not in Home)? Is there a way to encrypt a folder, which is not in Home (/home/user/) but even in a different partition, so only my user can access/read contained files?  Alternatively, I would like to understand if it is possible to turn a complete ext4 partition into an encrypted volume, which would be mounted at user login.  If possible, I would like to make the change without reinstalling Ubuntu.  My PC has (mount output):  /dev/sda1 on / type ext4 (rw,errors=remount-ro) /dev/sda3 on /home type ext4 (rw) /dev/sda4 on /home/igor/Personale type ext4 (rw)   sda4 is the partition containing folders I would like to protect.