Multistage Wiener filter (MSWF) is a very efficient algorithm for adaptive array processing because of low-complexity and prominent rank-reduction advantage. However, if training sample data was contaminated by outliers, especially when outliers having the same DOA with target emerge, the MSWF results will be decreased severely. In this paper, MSWFs backward iteration was improved, and median cascaded canceller (MCC) strategy was adopted so that optimal weighting calculation can be obtained via sorting and median processing, meaning impact of outliers were removed effectively. Blocking matrix solving of MSWF forward iteration was completed by Householder transform to enhance fix-point format performance. The new-designed algorithm attained excellent compromise between robustness and complexity. To verify presented algorithm's performance, array with 50 elements was established in simulation platform, and the simulated results also proved it can cope with outlier-contaminated applications effectively.
LLE is a very effective non-linear dimension reduction algorithm and widely explored in machine learning, pattern recognition, data mining and etc. Locally linear, Globally non-linear has always been regarded as the features and advantages of LLE. However, the theoretical derivation presented in this paper shows that when the size of neighborhood is larger than the dimension of the space in which the data are presented, LLE is no longer global nonlinear and almost has the same effect as PCA in dimensionality reduction. At present, a lot of literatures on LLE verify their results on Swiss Roll, Punctured Sphere, Twin Peaks, etc. These manifolds are presented in the three-dimensional Euclidean space and the size of neighborhood is always larger than three to prevent too small to be effective. But in these cases, LLE cannot play its advantage of nonlinearity.
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