TY - JOUR
A1 - Zien, Alexander
A1 - Rätsch, Gunnar
A1 - Mika, Sebastian
A1 - Schölkopf, Bernhard
A1 - Lengauer, Thomas
A1 - Müller, Klaus-Robert
T1 - Engineering support vector machine kernels that recognize translation initiation sites
Y1 - 2000
SN - 1367-4803
ER -
TY - JOUR
A1 - Ziehe, Andreas
A1 - Müller, Klaus-Robert
A1 - Nolte, G.
A1 - Mackert, B.-M.
A1 - Curio, Gabriel
T1 - Artifact reduction in magnetoneurography based on time-delayed second-order correlations
Y1 - 2000
ER -
TY - JOUR
A1 - Ziehe, Andreas
A1 - Kawanabe, Motoaki
A1 - Harmeling, Stefan
T1 - Blind separation of post-nonlinear mixtures using linearizing transformations and temporal decorrelation
N2 - We propose two methods that reduce the post-nonlinear blind source separation problem (PNL-BSS) to a linear BSS problem. The first method is based on the concept of maximal correlation: we apply the alternating conditional expectation (ACE) algorithm-a powerful technique from nonparametric statistics-to approximately invert the componentwise nonlinear functions. The second method is a Gaussianizing transformation, which is motivated by the fact that linearly mixed signals before nonlinear transformation are approximately Gaussian distributed. This heuristic, but simple and efficient procedure works as good as the ACE method. Using the framework provided by ACE, convergence can be proven. The optimal transformations obtained by ACE coincide with the sought-after inverse functions of the nonlinearitics. After equalizing the nonlinearities, temporal decorrelation separation (TDSEP) allows us to recover the source signals. Numerical simulations testing "ACE-TD" and "Gauss-TD" on realistic examples are performed with excellent results
Y1 - 2004
SN - 1532-4435
ER -
TY - THES
A1 - Ziehe, Andreas
T1 - Blind source separation based on joint diagonalization of matrices with applications in biomedical signal processing
T1 - Blinde Signalquellentrennung beruhend auf simultaner Diagonalisierung von Matrizen mit Anwendungen in der biomedizinischen Signalverarbeitung
T1 - Blinde Signalquellentrennung beruhend auf simultaner Diagonalisierung von Matrizen mit Anwendungen in der biomedizinischen Signalverarbeitung
N2 - This thesis is concerned with the solution of the blind source separation problem (BSS). The BSS problem occurs frequently in various scientific and technical applications. In essence, it consists in separating meaningful underlying components out of a mixture of a multitude of superimposed signals. In the recent research literature there are two related approaches to the BSS problem: The first is known as Independent Component Analysis (ICA), where the goal is to transform the data such that the components become as independent as possible. The second is based on the notion of diagonality of certain characteristic matrices derived from the data. Here the goal is to transform the matrices such that they become as diagonal as possible. In this thesis we study the latter method of approximate joint diagonalization (AJD) to achieve a solution of the BSS problem. After an introduction to the general setting, the thesis provides an overview on particular choices for the set of target matrices that can be used for BSS by joint diagonalization. As the main contribution of the thesis, new algorithms for approximate joint diagonalization of several matrices with non-orthogonal transformations are developed. These newly developed algorithms will be tested on synthetic benchmark datasets and compared to other previous diagonalization algorithms. Applications of the BSS methods to biomedical signal processing are discussed and exemplified with real-life data sets of multi-channel biomagnetic recordings.
N2 - Diese Arbeit befasst sich mit der Lösung des Problems der blinden Signalquellentrennung (BSS). Das BSS Problem tritt häufig in vielen wissenschaftlichen und technischen Anwendungen auf. Im Kern besteht das Problem darin, aus einem Gemisch von überlagerten Signalen die zugrundeliegenden Quellsignale zu extrahieren. In wissenschaftlichen Publikationen zu diesem Thema werden hauptsächlich zwei Lösungsansätze verfolgt: Ein Ansatz ist die sogenannte "Analyse der unabhängigen Komponenten", die zum Ziel hat, eine lineare Transformation V der Daten X zu finden, sodass die Komponenten Un der transformierten Daten U = V X (die sogenannten "independent components") so unabhängig wie möglich sind. Ein anderer Ansatz beruht auf einer simultanen Diagonalisierung mehrerer spezieller Matrizen, die aus den Daten gebildet werden. Diese Möglichkeit der Lösung des Problems der blinden Signalquellentrennung bildet den Schwerpunkt dieser Arbeit. Als Hauptbeitrag der vorliegenden Arbeit präsentieren wir neue Algorithmen zur simultanen Diagonalisierung mehrerer Matrizen mit Hilfe einer nicht-orthogonalen Transformation. Die neu entwickelten Algorithmen werden anhand von numerischen Simulationen getestet und mit bereits bestehenden Diagonalisierungsalgorithmen verglichen. Es zeigt sich, dass unser neues Verfahren sehr effizient und leistungsfähig ist. Schließlich werden Anwendungen der BSS Methoden auf Probleme der biomedizinischen Signalverarbeitung erläutert und anhand von realistischen biomagnetischen Messdaten wird die Nützlichkeit in der explorativen Datenanalyse unter Beweis gestellt.
KW - Signaltrennung
KW - Mischung
KW - Diagonalisierung
KW - Bioelektrisches Signal
KW - Magnetoencephalographie
KW - Elektroencephalographie
KW - Signalquellentrennung
KW - Matrizen-Eigenwertaufgabe
KW - Simultane Diagonalisierung
KW - Optimierungsproblem
KW - blind source separation
KW - BSS
KW - ICA
KW - independent component analysis
KW - approximate joint diagonalization
KW - EEG
KW - MEG
Y1 - 2005
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-5694
ER -
TY - THES
A1 - Zhou, Wei
T1 - Access control model and policies for collaborative environments
Y1 - 2008
CY - Potsdam
ER -
TY - JOUR
A1 - Zender, Raphael
A1 - Metzler, Richard
A1 - Lucke, Ulrike
T1 - FreshUP-A pervasive educational game for freshmen
JF - Pervasive and mobile computing
N2 - Students beginning their studies at university face manifold problems such as orientation in a new environment and organizing their courses. This article presents the implementation and successful empirical evaluation of the pervasive browser-based educational game "FreshUP", which aims at helping to overcome the initial difficulties of freshmen. In contrast to a conventional scavenger hunt, mobile pervasive games like FreshUP, bridging in-game and real world activities, have the potential to provide help in a motivating manner using new technology which is currently becoming more and more common. (C) 2013 Elsevier B.V. All rights reserved.
KW - Pervasive game
KW - Campus
KW - Freshmen
KW - e-learning
KW - Mobile devices
KW - SOA
KW - Evaluation
Y1 - 2014
U6 - https://doi.org/10.1016/j.pmcj.2013.09.003
SN - 1574-1192
SN - 1873-1589
VL - 14
SP - 47
EP - 56
PB - Elsevier
CY - Amsterdam
ER -
TY - THES
A1 - Zarezadeh, Aliakbar
T1 - Distributed smart cameras : architecture and communication protocols
Y1 - 2012
CY - Potsdam
ER -
TY - THES
A1 - Yang, Haojin
T1 - Automatic video indexing and retrieval using video ocr technology
Y1 - 2013
CY - Potsdam
ER -
TY - GEN
A1 - Xenikoudakis, Georgios
A1 - Ahmed, Mayeesha
A1 - Harris, Jacob Colt
A1 - Wadleigh, Rachel
A1 - Paijmans, Johanna L. A.
A1 - Hartmann, Stefanie
A1 - Barlow, Axel
A1 - Lerner, Heather
A1 - Hofreiter, Michael
T1 - Ancient DNA reveals twenty million years of aquatic life in beavers
T2 - Current biology : CB
N2 - Xenikoudakis et al. report a partial mitochondrial genome of the extinct giant beaver Castoroides and estimate the origin of aquatic behavior in beavers to approximately 20 million years. This time estimate coincides with the extinction of terrestrial beavers and raises the question whether the two events had a common cause.
Y1 - 2020
U6 - https://doi.org/10.1016/j.cub.2019.12.041
SN - 0960-9822
SN - 1879-0445
VL - 30
IS - 3
SP - R110
EP - R111
PB - Current Biology Ltd.
CY - London
ER -
TY - JOUR
A1 - Wübbeler, G.
A1 - Ziehe, Andreas
A1 - Mackert, B.-M.
A1 - Müller, Klaus-Robert
A1 - Trahms, L.
A1 - Curio, Gabriel
T1 - Independent component analysis of noninvasively recorded cortical magnetic DC-fields in humans
Y1 - 2000
ER -