TY - JOUR
A1 - Zieris, Holger
A1 - Gerstberger, Herbert
A1 - Müller, Wolfgang
T1 - Using Arduino-Based Experiments to Integrate Computer Science Education and Natural Science
JF - KEYCIT 2014 - Key Competencies in Informatics and ICT
N2 - Current curricular trends require teachers in Baden-
Wuerttemberg (Germany) to integrate Computer Science (CS) into
traditional subjects, such as Physical Science. However, concrete guidelines
are missing. To fill this gap, we outline an approach where a
microcontroller is used to perform and evaluate measurements in the
Physical Science classroom.
Using the open-source Arduino platform, we expect students to acquire
and develop both CS and Physical Science competencies by using a
self-programmed microcontroller. In addition to this combined development
of competencies in Physical Science and CS, the subject matter
will be embedded in suitable contexts and learning environments,
such as weather and climate.
KW - Computer Science Education
KW - Natural Science Education
KW - Inquiry-based Learning
KW - Physical Science
KW - Measurement
KW - Arduino
KW - Sensors
Y1 - 2015
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-82938
SN - 1868-0844
SN - 2191-1940
IS - 7
SP - 381
EP - 389
PB - Universitätsverlag Potsdam
CY - Potsdam
ER -
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 -
TY - THES
A1 - Wust, Johannes
T1 - Mixed workload managment for in-memory databases
BT - executing mixed workloads of enterprise applications with TAMEX
Y1 - 2015
ER -
TY - BOOK
A1 - Wu, K.
A1 - Karri, R.
A1 - Kuznetsov, Grigory
A1 - Gössel, Michael
T1 - Low Cost Concurrent Error Detection for the Advanced Encryption Standart
T3 - Preprint / Universität Potsdam, Institut für Informatik
Y1 - 2003
SN - 0946-7580
VL - 2003, 8
PB - Univ.
CY - Potsdam
ER -
TY - JOUR
A1 - Wong, P.
A1 - Besnard, Philippe
T1 - Paraconsistent reasoning as an analytical tool
Y1 - 2000
SN - 1367-0751
ER -
TY - THES
A1 - Wolter, Christian
T1 - A methodology for model-driven process security
Y1 - 2010
CY - Potsdam
ER -
TY - THES
A1 - Wist, Dominic
T1 - Attacking complexity in logic synthesis of asynchronous circuits
T1 - Komplexitätsbewältigung in der Logiksynthese asynchroner Schaltungen
N2 - Most of the microelectronic circuits fabricated today are synchronous, i.e. they are driven by one or several clock signals. Synchronous circuit design faces several fundamental challenges such as high-speed clock distribution, integration of multiple cores operating at different clock rates, reduction of power consumption and dealing with voltage, temperature, manufacturing and runtime variations. Asynchronous or clockless design plays a key role in alleviating these challenges, however the design and test of asynchronous circuits is much more difficult in comparison to their synchronous counterparts. A driving force for a widespread use of asynchronous technology is the availability of mature EDA (Electronic Design Automation) tools which provide an entire automated design flow starting from an HDL (Hardware Description Language) specification yielding the final circuit layout. Even though there was much progress in developing such EDA tools for asynchronous circuit design during the last two decades, the maturity level as well as the acceptance of them is still not comparable with tools for synchronous circuit design. In particular, logic synthesis (which implies the application of Boolean minimisation techniques) for the entire system's control path can significantly improve the efficiency of the resulting asynchronous implementation, e.g. in terms of chip area and performance. However, logic synthesis, in particular for asynchronous circuits, suffers from complexity problems. Signal Transitions Graphs (STGs) are labelled Petri nets which are a widely used to specify the interface behaviour of speed independent (SI) circuits - a robust subclass of asynchronous circuits. STG decomposition is a promising approach to tackle complexity problems like state space explosion in logic synthesis of SI circuits. The (structural) decomposition of STGs is guided by a partition of the output signals and generates a usually much smaller component STG for each partition member, i.e. a component STG with a much smaller state space than the initial specification. However, decomposition can result in component STGs that in isolation have so-called irreducible CSC conflicts (i.e. these components are not SI synthesisable anymore) even if the specification has none of them. A new approach is presented to avoid such conflicts by introducing internal communication between the components. So far, STG decompositions are guided by the finest output partitions, i.e. one output per component. However, this might not yield optimal circuit implementations. Efficient heuristics are presented to determine coarser partitions leading to improved circuits in terms of chip area. For the new algorithms correctness proofs are given and their implementations are incorporated into the decomposition tool DESIJ. The presented techniques are successfully applied to some benchmarks - including 'real-life' specifications arising in the context of control resynthesis - which delivered promising results.
N2 - Moderner Schaltungsentwurf fokussiert hauptsächlich synchrone Schaltungstechnik mit allen inhärenten Problemen. Asynchone (d.h. ungetaktete) Schaltungen zeichnen sich jedoch nicht nur durch das Fehlen der Taktversatzproblematik gegenüber ihren synchronen Pendents aus, sondern auch insbesondere durch geringeren Energieverbrauch, günstigere EMV-Eigenschaften, hohe Performance, Modularität und Robustheit gegenüber Schwankungen in der Spannungsversorgung, im Herstellungsprozess sowie Temperaturunterschieden. Diese Vorteile werden mit höherer Integration sowie höheren Taktraten signifikanter. Jedoch ist der Entwurf und auch der Test asynchroner Schaltungen erheblich schwieriger verglichen mit synchronen Schaltungen. Entwurfswerkzeuge zur Synthese asynchroner Schaltungen aus Hochsprachen-Spezifikationen sind zwar inzwischen verfügbar, sie sind jedoch noch nicht so ausgereift und bei weitem noch nicht so akzeptiert in der Industrie, wie ihre Äquivalente für den synchronen Schaltungsentwurf. Insbesondere fehlt es an Werkzeugunterstützung im Bereich der Logiksynthese komplexer Steuerungen („Controller“), welche kritisch für die Effizienz – z.B. in Bezug auf Chipfläche und Geschwindigkeit – der resultierenden Schaltungen oder Systeme ist. Zur Spezifikation von Steuerungen haben sich Signalflankengraphen („signal transition graphs“, STGs) bewährt, die auch als Entwurfseinstieg für eine Logiksynthese von SI-Schaltungen („speed independent“) verwendet werden. (SI-Schaltungen gelten als sehr robuste asynchrone Schaltungen.) Aus den STGs werden zwecks Logiksynthese Automaten abgeleitet werden, deren Zustandszahl aber oft prohibitiv groß werden kann. Durch sogenannte STG-Dekomposition wird die Logiksynthese einer komplexen Schaltung ermöglicht, was bislang aufgrund von Zustandsexplosion oft nicht möglich war. Dabei wird der Spezifikations-STG laut einer gegebenen Partition von Ausgangssignalen in viele kleinere Teilnetze dekomponiert, wobei zu jedem Partitionsblock ein Teilnetz – mit normalerweise signifikant kleinerem Zustandsraum im Vergleich zur Spezifikation – erzeugt wird. Zu jedem Teilnetz wird dann eine Teilschaltung (Komponente) mittels Logiksynthese generiert. Durch die Anwendung von STG-Dekomposition können jedoch Teilnetze erzeugt werden, die sogenannte irreduzible CSC-Konflikte aufweisen (d.h. zu diesen Teilnetzen kann keine SI-Schaltung erzeugt werden), obwohl die Spezifikation keine solchen Konflikte hatte. Diese Arbeit präsentiert einen neuen Ansatz, welcher die Entstehung solcher irreduziblen Konflikte vermeidet, und zwar durch die Einführung interner Kommunikation zwischen den (zu den Teilnetzen gehörenden) Schaltungskomponenten. Bisher werden STG-Dekompositionen total durchgeführt, d.h. pro resultierender Komponente wird ein Ausgangssignal erzeugt. Das führt gewöhnlich nicht zu optimalen Schaltungsimplementierungen. In dieser Arbeit werden Heuristiken zur Bestimmung gröberer Ausgabepartitionen (d.h. Partitionsblöcke mit mehreren Ausgangssignalen) vorgestellt, die zu kleineren Schaltungen führen. Die vorgestellten Algorithmen werden formal abgesichert und wurden in das bereits vorhandene Dekompositionswerkzeug DESIJ integriert. An praxisrelevanten Beispielen konnten die vorgestellten Verfahren erfolgreich erprobt werden.
KW - Asynchrone Schaltung
KW - Logiksynthese
KW - Komplexitätsbewältigung
KW - STG-Dekomposition
KW - CSC
KW - asynchronous circuit
KW - logic synthesis
KW - speed independence
KW - STG decomposition
KW - CSC
Y1 - 2011
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59706
ER -
TY - JOUR
A1 - Willig, Andreas
A1 - Mitschke, Robert
T1 - Results of bit error measurements with sensor nodes and casuistic consequences for design of energy-efficient error control schemes
N2 - For the proper design of energy-efficient error control schemes some insight into channel error patterns is needed. This paper presents bit error and packet loss measurements taken with sensor nodes running the popular RFM
Y1 - 2006
SN - 978-3-540-32158-3
ER -
TY - JOUR
A1 - Willig, Andreas
A1 - Matheus, K.
A1 - Wolisz, A.
T1 - Wireless technology in industrial networks
N2 - With the success of wireless technologies in consumer electronics, standard wireless technologies are envisioned for the deployment in industrial environments as well. Industrial applications involving mobile subsystems or just the desire to save cabling make wireless technologies attractive. Nevertheless, these applications often have stringent requirements on reliability and timing. In wired environments, timing and reliability are well catered for by fieldbus systems (which are a mature technology designed to enable communication between digital controllers and the sensors and actuators interfacing to a physical process). When wireless links are included, reliability and timing requirements are significantly more difficult to meet, due to the adverse properties of the radio channels. In this paper we thus discuss some key issues coming up in wireless fieldbus and wireless industrial communication systems:1)fundamental problems like achieving timely and reliable transmission despite channel errors; 2) the usage of existing wireless technologies for this specific field of applications; and 3) the creation of hybrid systems in which wireless stations are included into existing wired systems
Y1 - 2005
SN - 0018-9219
ER -
TY - THES
A1 - Wildner, Uwe
T1 - CASC : compiler assisted self-checking of structural integrity
Y1 - 1997
ER -
TY - JOUR
A1 - Wildner, Uwe
T1 - Experimental evaluation of assigned signature checking with return address hashing on different platforms
Y1 - 1997
ER -