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Category Archives: coding
3D Matrix Multiplication Tricks
Recently, I came across times 3D matrix multiplication in Matlab. It is for frequency domain signal processing, specifically, frequencydependent multichannel Wiener filter. Here, 3D matrix multiplication means 2D matrix multiplication at each frequency (or other parameters): Given and which are … Continue reading
Blacklist IPs that attack SSH and FTP services on a Linux machine
I manage a Linux server (Redhat EL4, kernel version 2.6.934). Yesterday, I found the server was attacked relentlessly from 121.101.223.211. It seemed to be a brutal force dictionary attack. What to do then? The obvious way is to manually add that IP … Continue reading