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Grunewald, Germany

Nikulin V.V.,Franklin University | Nikulin V.V.,Bernstein Center for Computational Neuroscience | Nolte G.,Fraunhofer FIRST | Curio G.,Franklin University | Curio G.,Bernstein Center for Computational Neuroscience
Clinical Neurophysiology | Year: 2012

Objective: We present a novel method for the extraction of neuronal components showing cross-frequency phase synchronization. Methods: In general the method can be applied for the detection of phase interactions between components with frequencies f1 and f2, where f2≈ rf1 and r is some integer. We refer to the method as cross-frequency decomposition (CFD), which consists of the following steps: (a) extraction of f1-oscillations with the spatio-spectral decomposition algorithm (SSD); (b) frequency modification of the f1-oscillations obtained with SSD; and (c) finding f2-oscillations synchronous with f1-oscillations using least-squares estimation. Results: Our simulations showed that CFD was capable of recovering interacting components even when the signal-to-noise ratio was as low as 0.01. An application of CFD to the real EEG data demonstrated that cross-frequency phase synchronization between alpha and beta oscillations can originate from the same or remote neuronal populations. Conclusions: CFD allows a compact representation of the sets of interacting components. The application of CFD to EEG data allows differentiating cross-frequency synchronization arising due to genuine neurophysiological interactions from interactions occurring due to quasi-sinusoidal waveform of neuronal oscillations. Significance: CFD is a method capable of extracting cross-frequency coupled neuronal oscillations even in the presence of strong noise. © 2011 International Federation of Clinical Neurophysiology. Source


Schutt A.,University of Melbourne | Wolf A.,Fraunhofer FIRST
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

The recent success of the lazy clause generator (a hybrid of a FD and a SAT solver) on resource-constrained project scheduling problems (RCPSP) shows the importance of the global cumulative constraint to tackle these problems. A key for an efficient cumulative propagator is a fast and correct pruning of time-bounds. The not-first/not-last rule (which is not subsumed by other rules) detects activities that cannot be run at first/last regarding to an activity set and prunes their time bounds. This paper presents a new sound not-first/not-last pruning algorithm which runs in O(n2 log n), where n is the number of activities. It may not find the best adjustments in the first run, but after at most n iterations. This approach of iteration fits the setup of constraint propagation quite naturally offering the opportunity that a fixed point is reached more efficiently. Moreover, it uses a novel approach of generation of some "artificial" activities in the context of triggering pruning rules correctly. In experiments on RCPSP amongst others from the well-established PSPLib we show that the algorithm runs negligible more often than a complete algorithm while taking its advantage from the lower - to the best of our knowledge the lowest known - runtime complexity. © 2010 Springer-Verlag. Source


Asselmeyer-Maluga T.,German Aerospace Center | Rose H.,Fraunhofer FIRST
General Relativity and Gravitation | Year: 2012

In this paper we discuss the question how matter may emerge from space. For that purpose we consider the smoothness structure of spacetime as underlying structure for a geometrical model of matter. For a large class of compact 4-manifolds, the elliptic surfaces, one is able to apply the knot surgery of Fintushel and Stern to change the smoothness structure. The influence of this surgery to the Einstein-Hilbert action is discussed. Using the Weierstrass representation, we are able to show that the knotted torus used in knot surgery is represented by a spinor fulfilling the Dirac equation and leading to a Dirac term in the Einstein-Hilbert action. For sufficient complicated links and knots, there are "connecting tubes" (graph manifolds, torus bundles) which introduce an action term of a gauge field. Both terms are genuinely geometrical and characterized by the mean curvature of the components. We also discuss the gauge group of the theory to be U(1) × SU(2) × SU(3). © 2012 Springer Science+Business Media, LLC. Source


Serbedzija N.,Fraunhofer FIRST
Proceedings - International Conference on Software Engineering | Year: 2010

Reflective assistance is concerned with the construction of flexible 'smart' systems that control the eldercare environment, adapting the functioning to the needs of the individual in real-time. In order to achieve this goal, systems must be capable of monitoring the behaviour of the elderly people and responding to dynamic changes in their performance, physical and psychological situation. This paper describes how reflective approach can be used to design and develop a home environment that offers medicare, rehabilitation exercises and improved comfort of elderly inhabitants. Copyright 2010 ACM. Source


Serbedzija N.,Fraunhofer FIRST
Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST | Year: 2012

User-centric systems call for novel methods and tools for a tight and implicit man machine interaction. Often highly personalized system are sensitive and reactive to user psychological, social and physical situation. However providing such a support may cross the barriers of our privacy or may have impacts on us that we do not necessarily agree upon. © 2012 Springer-Verlag Berlin Heidelberg. Source

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