We experiment with variations of a method for constructing low-density paritycheck codes to investigate the effect on decoding performance under the sumproduct algorithm. The method uses circulant permutation matrices or affine permutation matrices as building blocks. We have developed an algorithm to choose these matrices so as to maximize the girth of the parity-check matrix. Substantial perf...

We give conditions under which we can solve precisely the Blind Source Separation problem (BSS) in the underdetermined case (less sensors than sources) uniquely, up to permutation and scaling of sources. Under this conditions, which include information about sparseness of the sources (and hence we call the problem sparse component analysis (SCA)), we can 1) identify the mixing matrix (up to sca...

This paper presents a method for solving the permutation problem of frequency domain blind source separation (BSS) when the number of source signals is large, and the potential source locations are omnidirectional. We propose a combination of small and large spacing sensor pairs with various axis directions in order to obtain proper geometric information for solving the permutation problem. Exp...

A large number of generating functions for permutation statistics can be obtained by applying homomorphisms to simple symmetric function identities. In particular, a large number of generating functions involving the number of descents of a permutation σ, des(σ), arise in this way. For any given finite set S of positive integers, we develop a method to produce similar generating functions for t...

We introduce the concept of regular quantum graphs and construct connected quantum graphs with discrete symmetries. The method is based on a decomposition of the quantum propagator in terms of permutation matrices which control the way incoming and outgoing channels at vertex scattering processes are connected. Symmetry properties of the quantum graph as well as its spectral statistics depend o...

In this paper, we propose a new method for longitudinal shape analysis that fits a linear mixed-effects model, while simultaneously optimizing correspondences on a set of anatomical shapes. Shape changes are modeled in a hierarchical fashion, with the global population trend as a fixed effect and individual trends as random effects. The statistical significance of the estimated trends are evalu...

In this paper a blind source separation algorithm in convolutive environment is presented. In order to avoid the classical permutation ambiguity in the frequency domain solution, a geometrical constraint is considered. Moreover a beamformer algorithm is integrated with the proposed solution: in this way the directivity pattern of the proposed architecture can take into account the residual perm...