To utilize the intrinsic group information from these sub-STV descriptors within one video for action classification, we adopt the locality-Constrained Group Sparse Representation (LGSR) to classify actions.
In order to guarantee that the class-special dictionaries in LGSR are over complete, PCA is adopted to reduce the dimension of the sub-STV descriptor to 400.
Similar to LGSR, the maxWIRE criterion is also used in SRC.
KTH UCF sports Weizmann KNN + SPM 91.7 82.8 93.5 KNN + MLSC 94.4 85.6 96.5 TABLE 3: Comparison results between LGSR and SRC (UNIT: %).
Recently interest in large-scale ecological patterns such as the LGSR has resurged.
Stevens's (1989, 1992) hypothesis suggests a link between the LGSR and another global-scale pattern: the tendency for species geographical ranges to decrease in size toward the equator.
Despite widespread interest in explaining the LGSR and the fact that much recent empirical research on the subject has been influenced by the Stevens (1989, 1992) hypothesis, one central question remains untested: Could the Stevens hypothesis suffice to explain the observed latitudinal gradient in species richness?
Stevens's (1989, 1992) hypothesized mechanism for generation of the LGSR includes a role for the rescue effect.
In sum, Stevens's verbal model (Stevens 1989, 1992), modeled mathematically here, falls short of generating a LGSR qualitatively consistent with that of the real world.
If the combination of Rapoport's rule and the rescue effect generates a reverse gradient in species richness, we are left with the question of how to generate a "correct" LGSR. To counteract the effects of range size, something must generate a nonrandom distribution of species range centerpoints on the surface of the globe.
Regional sampling shows that a peak in species richness appears at the equator, mimicking the real world LGSR (Fig.
With these parameter values, the interaction between Rapoport's rule, the rescue effect, and competition produced results that were qualitatively different from those seen in the previous versions of the model and consistent with the empirically observed LGSR (Fig.