Cram\'er-Rao Bounds for Complex-Valued Independent Component Extraction: Determined and Piecewise Determined Mixing Models

This paper presents Cram\'er-Rao Lower Bound (CRLB) for the complex-valued Blind Source Extraction (BSE) problem based on the assumption that the target signal is independent of the other signals. Two instantaneous mixing models are considered. First, we consider the standard determined mixing model used in Independent Component Analysis (ICA) where the mixing matrix is square and non-singular and the number of the latent sources is the same as that of the observed signals. The CRLB for Independent Component Extraction (ICE) where the mixing matrix is re-parameterized in order to extract only one independent target source is computed. The target source is assumed to be non-Gaussian or non-circular Gaussian while the other signals (background) are circular Gaussian or non-Gaussian. The results confirm some previous observations known for the real domain and bring new results for the complex domain. Also, the CRLB for ICE is shown to coincide with that for ICA when the non-Gaussianity of background is taken into account. %unless the assumed sources' distributions are misspecified. Second, we extend the CRLB analysis to piecewise determined mixing models. Here, the observed signals are assumed to obey the determined mixing model within short blocks where the mixing matrices can be varying from block to block. However, either the mixing vector or the separating vector corresponding to the target source is assumed to be constant across the blocks. The CRLBs for the parameters of these models bring new performance bounds for the BSE problem.Comment: 25 pages, 8 figure

Role generálních tajemníků OSN v mezinárodních vztazích

Diplomová práce pojednává o významu generálních tajemníků v mezinárodních vztazích. Zaměřuje se na zkoumání dosavadních tajemníků a hodnotí jejich výkon. Cílem práce je identifikovat kritické faktory úspěšného výkonu funkce generálního tajemníka, přičemž hlavní důraz je kladen na individuální předpoklady jednotlivých tajemníků

Reflections of the 1989 Revolution in Chosen Dailies

Studium humanitní vzdělanosti - Společenskovědní modulLiberal Arts and Humanities - Social Sciences ModuleFaculty of HumanitiesFakulta humanitních studi

Web audit

Information audit is a quickly developing field, which today has a wide scope of use. This thesis is mainly focused on an explanation of information audit concept in general and also on one of its parts - web audit. This thesis brings offers an overview of several specific information audit methods, which are today often used and quated as a source by many authors and also used by companies in this area. The core of the thesis is focused on web auditing, the most common techniques, the most prevalent approaches and the situation in this field in the Czech market. Lastly, the author provides an analysis of IDC CEMA's company website, including further recommendation for its optimization

Family House

katedra architektur

Heuristics in blind source separation

This paper deals with application of heuristic algorithms (DEBR, MCRS) in blind source separation (BSS). BSS methods focus on a separation of the (source) signal from a linear mixture. The idea of using heuristic algorithms is introduced on the independent component extraction (ICE) model. The motivation for considering heuristics is to obtain an initial guess needed by many ICE algorithms. Moreover, the comparison of this initialization, and other algorithms accuracy is performed.\