Can you find any pattern in the two signals, green and blue? The blue signal is the brain wave (measured by NIRS) of a person when he is pressing some buttons (the timing of button pressing is shown i

Wavelet transform coherence (WTC) is a method for analyzing the coherence and phase lag between two time series as a function of both time and frequency (Chang and Glover 2010). Here I played with it

SVM is mostly commonly used for binary classifications. But one branch of SVM, SVM regression or SVR, is able to fit a continuous function to data. This is particularly useful when the predicted varia

Update 2021/2/27: If you find griddata3 not working, try to change griddata3 to griddata. I was asked where to get nirs2img script. Here it is. The download link is at the bottom of this article. nirs2img is to create an image file from the input data. Then theimage file can be viewed by a

Avoid using explicit loop if possible %calculating the sum of the product of corresponding element in two row vectors A and B %bad example s = 0; for i=1:100 s = s + A(i)*B(i); end %good example s = A*B'; Avoid increment memory allocation, inste

Standard phpBB captcha is broken. I modify it such that the user need to add the numbers in captcha images and enter the result (e.g. 1+2+3=6), instead of enter the original characters (e.g. ‘123’). Enter folder /includes/ucp edit file uc

AdaBoost is an algorithm to linearly combine many classifiers and form a much better classifier. It has been widely used in computer vision (e.g. identify faces in a picture or movie). Look at the following example: How it works? First, you have a tr

Assume you got correlation r=0.6 between two variables (N=10), is 0.6 significantly bigger than 0? Or if you observed r=0.98, is it significantly different from r=0.9? For these questions, we need to know the distribution of r of our sample, given th