Spurious principal components

Hockey sticks, principal components, and spurious significance

[1] The ‘‘hockey stick’’ shaped temperature reconstruction of Mann et al. (1998, 1999) has been widely applied. However it has not been previously noted in print that, prior to their principal components (PCs) analysis on tree ring networks, they carried out an unusual data transformation which strongly affects the resulting PCs. Their method, when tested on persistent red noise, nearly always ...

Reply to Ammann and Wahl: “comment on “hockey Sticks, Principal Components and Spurious Significance”

Comment on ‘‘Hockey sticks, principal components, and spurious significance’’ by S. McIntyre and R. McKitrick

[1] McIntyre and McKitrick [2005] (hereinafter referred to as MM05) point out a bias in the Mann et al. [1998] (hereinafter referred to as MBH98) Northern Hemisphere temperature reconstruction, one tending to enhance trends during the last century. Having reproduced the statistical results of MM05, this comment is prompted by further questions regarding appropriate implementation of principal c...

Reply to comment by von Storch and Zorita on ‘‘Hockey sticks, principal components, and spurious significance’’

[1] Von Storch and Zorita [2005] (hereinafter referred to as VZ) concur that the Mann et al. [1998] (hereinafter referred to as MBH98) principal component (PC) method ‘‘very often shows a hockey stick shaped pattern even if the data was by construction free of such structures’’ the Artificial Hockey Stick (AHS) effect. We did not claim that the AHS effect applied to all situations. We did claim...

Minimization of the Spurious Shot Boundaries Using Principal Components Decomposition and Progressive Nonlinear Filter

Shot boundary detection is an important for retrieval of visual media in multimedia system. Video temporal segmentation algorithms use thresholding techniques to identify both abrupt shot changes and gradual shot transitions. Thresholding methods frequently provide false positives due to large variations in gradual transition regions. The principal components decomposition and the progressive n...