Sliding window

Fig. 7.1. The British infrared telescope at Mauna Kea, Hawaii. The picture shows the housing for the 3.8 m diameter mirror, the supporting frame, and the interior of the aluminium dome with its sliding window ( 1979 by Photolabs, Royal Observatory, Edinburgh.)...

In a first simple model for target detection it is assumed that the background clutter can be described by a statistical model in which the different range cells inside the sliding window contain statistically independent identically exponentially distributed (iid) random variables X i,..., X/v. The probability density function (pdf) of exponentially distributed clutter variables is fully described by the equation ... 

The general idea of an ordered statistic is technically simple. To estimate the average noise and clutter power a single rank X(fc) of the ordered statistic is used instead of the arithmetic mean. In this case a very few large amplitudes in the sliding window have a very small effect on the estimation result. OS-CFAR is robust in multiple target situations. The threshold is hardly influenced by a second or third target inside the window. 

All amplitudes inside the sliding window are sorted according to increasing magnitude. 

Censored CFAR. Richard and Dillard [19] have proposed a CFAR procedure which is based on CA-CFAR but is already close to the general OS-CFAR idea when they are calculating the largest m values inside the sliding window and excluding these values from the arithmetic mean calculation. This step makes modified CA-CFAR less sensitive in mul-... 

Figure 2 shows the results of the IF analysis, revealing strong modulation at 50 on1 and other low frequency modes, similar to observations by Champion et al. [10][11] For comparison, the IF was also calculated using a sliding window FFT method, yielding similar results as shown in Figure 2. The observation of these low frequency modes is perhaps the most important result of the study. The 50 cm 1 mode in particular has been identified with the doming motion of the heme [12] and the lower frequencies can be correlated to the globin...

Figure 2 - Left IF analysis, using a 100 cm 1 Gaussian filter (solid) (other filter widths gave similar results). The sliding window FFT results are shown for comparison (squares). The inset illustrates the exponential decay of the v7 mode. Right FFT of the IF showing a large peak near 50 cm 1. The resolution of this plot is fundamentally limited by the decay of the v7 mode.

X length of sliding window along copolymer sequence... 

Ladies GS, Bannon GA, Silvanovich A, Cressman RF. Comparison of conventional FASTA identity searches with the 80 amino acid sliding window FASTA search for the elucidation of potential identities to known allergens. Mol Nutr Food Res. 2007 51(8) 985-998. 

It has been noted several years ago that promoters and most likely also other regulatory regions like enhancers contain more transcription factor binding sites that non-regulatory sequences. An analysis of the relative frequencies of such sites within a sliding window therefore can yield some information about the potential regulatory character of a stretch of DNA, which is the prototype of simple statistical models. Several programs exist that rely to some extent on this type of statistics. 

To visualize the level of conservation across the alignment, similarity plots are created that graph the level of conservation in sliding windows across the alignment (see Note 7). 

At this point we also want to add that we are painfully aware of the fact that the process of first slicing the alignments and the reclustering of them is not optimal. Ideally, one would like to predict conserved RNA structures locally without sliding windows. Although this should be possible (14) and we are working on a local version of RNAz, the sliding window approach is currently the only reasonable protocol. 

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