PCA

Making sense of principal component analysis, eigenvectors & eigenvalues

http://stats.stackexchange.com/questions/2691/making-sense-of-principal-component-analysis-eigenvectors-eigenvalues

In-Network PCA and Anomaly Detection
http://papers.nips.cc/paper/3156-in-network-pca-and-anomaly-detection.pdf

Mining Console Logs for Large-Scale System Problem Detection
https://www.usenix.org/legacy/event/sysml08/tech/full_papers/xu/xu.pdf