Complementarity methods in the analysis of piecewise linear dynamical systems

The main object of this thesis is a class of piecewise linear dynamical systems that are related both to system theory and to mathematical programming. The dynamical systems in this class are known as complementarity systems. With regard to these nonlinear and nonsmooth dynamical systems, the research in the thesis concentrates on two themes: well-posedness and approximations. The well-posedness issue, in the sense of existence and uniqueness of solutions, is of considerable importance from a model validation point of view. In the thesis, sufficient conditions are established for the well-posedness of complementarity systems. Furthermore, an investigation is made of the convergence of approximations of these systems with an eye towards simulation

Two explorations in Dynamical Systems and Mechanics: avoiding cones conditions and higher dimensional twist. Directional friction in bio-inspired locomotion

This thesis contains the work done by Paolo Gidoni during the doctorate programme in Matematical Analysis at SISSA, under the supervision of A. Fonda and A. DeSimone. The thesis is composed of two parts: "Avoiding cones conditions and higher dimensional twist" and "Directional friction in bio-inspired locomotion"

Parameter identification for biological models

This thesis concerns the identification of dynamic models in systems biology. and is structured into two parts. Both parts concern building dynamic models from observed data, but are quite different in perspective, rationale and mathematics. The first part considers the development of novel identification techniques that are particularly tailored to (molecular) biology and considers two approaches. The first approach reformulates the parameter estimation problem as a feasibility problem. This reformulation allows the invalidation of models by analysing entire parameter regions. The second approach utilises nonlinear observers and a transformation of the model equations into parameter free coordinates. The parameter free coordinates allow the design of a globally convergent observer, which in turn estimates the parameter values, and further, allows to identify modelling errors or unknown inputs/influences. Both approaches are bottom up approaches that require a mechanistic understanding of the underlying processes (in terms of a biochemical reaction network) leading to complex nonlinear models. The second part is an example of what can be done with classical, well developed tools from systems identification when applied to hitherto unattended problems.In particular, part two of my thesis develops a modelling framework for rat movements in an experimental setup that it widely used to study learning and memory.The approach is a top down approach that is data driven resulting in simple linear models

Self-organization in heterogeneous biological systems

Self-organization is an ubiquitous and fundamental process that underlies all living systems. In cellular organisms, many vital processes, such as cell division and growth, are spatially and temporally regulated by proteins -- the building blocks of life. To achieve this, proteins self-organize and form spatiotemporal patterns. In general, protein patterns respond to a variety of internal and external stimuli, such as cell shape or inhomogeneities in protein activity. As a result, the dynamics of intracellular pattern formation generally span multiple spatial and temporal scales. This thesis addresses the underlying mechanisms that lead to the formation of heterogeneous patterns. The main themes of this work are organized into three parts, which are summarized below. The first part deals with the general problem of mass-conserving reaction-diffusion dynamics in spatially non-uniform systems. In section 1 of chapter II, we study the dynamics of the E. coli Min protein system -- a paradigmatic model for pattern formation. More specifically, we consider a setup with a fixed spatial heterogeneity in a control parameter, and show that this leads to complex multiscale pattern formation. We develop a coarse-graining approach that enables us to explain and reduce the dynamics to the "hydrodynamic variables'' at large length and time scales. In another project, we consider a system where spatial heterogeneities are not imposed externally, but self-generated by the dynamics via a mechanochemical feedback loop between geometry and reaction-diffusion system (section 2 of chapter II). We show that the resulting dynamics can be explained from the phase-space geometry of the reaction-diffusion system. The second part focuses on how patterns in realistic cell geometries are controlled by shape and biochemical cues. We examine axis selection of PAR polarity patterns in C. elegans, where we show that spatial variations in the bulk-surface ratio and a tendency of the system to minimize the pattern interface yield robust long-axis polarization of PAR protein patterns (section 1 of chapter III). In a second project, we develop a theoretical model that explains the localization of the B. subtilis Min protein system (section 2 of chapter 3). We show that a biochemical cue -- which acts as a template for pattern formation -- guides and stabilizes Min patterns. In the third part, we study the coupling between lipid membranes and curvature-generating proteins. We demonstrate that myosin-VI motor proteins cooperatively bind to saddle-shaped regions of lipid membranes, and thereby induce large-scale membrane remodeling (section 1 of chapter IV). To understand the dynamics, we develop a coarse-grained geometric model and show that the emergence of regular spatial structures can be explained by a "push-pull'' mechanism: protein binding destabilizes the membrane shape at all length scales, and this is counteracted by line tension. Inspired by this system, we then investigate a general model for the dynamics of growing protein-lipid interfaces (section 2 of chapter IV). A key feature of the model is that the protein binding kinetics is explicitly coupled to the morphology of the interface. We show that such a coupling leads to turbulent dynamics and a roughening transition of the interface that is characterized by universal scaling behaviour

24th International Conference on Information Modelling and Knowledge Bases

In the last three decades information modelling and knowledge bases have become essentially important subjects not only in academic communities related to information systems and computer science but also in the business area where information technology is applied. The series of European – Japanese Conference on Information Modelling and Knowledge Bases (EJC) originally started as a co-operation initiative between Japan and Finland in 1982. The practical operations were then organised by professor Ohsuga in Japan and professors Hannu Kangassalo and Hannu Jaakkola in Finland (Nordic countries). Geographical scope has expanded to cover Europe and also other countries. Workshop characteristic - discussion, enough time for presentations and limited number of participants (50) / papers (30) - is typical for the conference. Suggested topics include, but are not limited to: 1. Conceptual modelling: Modelling and specification languages; Domain-specific conceptual modelling; Concepts, concept theories and ontologies; Conceptual modelling of large and heterogeneous systems; Conceptual modelling of spatial, temporal and biological data; Methods for developing, validating and communicating conceptual models. 2. Knowledge and information modelling and discovery: Knowledge discovery, knowledge representation and knowledge management; Advanced data mining and analysis methods; Conceptions of knowledge and information; Modelling information requirements; Intelligent information systems; Information recognition and information modelling. 3. Linguistic modelling: Models of HCI; Information delivery to users; Intelligent informal querying; Linguistic foundation of information and knowledge; Fuzzy linguistic models; Philosophical and linguistic foundations of conceptual models. 4. Cross-cultural communication and social computing: Cross-cultural support systems; Integration, evolution and migration of systems; Collaborative societies; Multicultural web-based software systems; Intercultural collaboration and support systems; Social computing, behavioral modeling and prediction. 5. Environmental modelling and engineering: Environmental information systems (architecture); Spatial, temporal and observational information systems; Large-scale environmental systems; Collaborative knowledge base systems; Agent concepts and conceptualisation; Hazard prediction, prevention and steering systems. 6. Multimedia data modelling and systems: Modelling multimedia information and knowledge; Contentbased multimedia data management; Content-based multimedia retrieval; Privacy and context enhancing technologies; Semantics and pragmatics of multimedia data; Metadata for multimedia information systems. Overall we received 56 submissions. After careful evaluation, 16 papers have been selected as long paper, 17 papers as short papers, 5 papers as position papers, and 3 papers for presentation of perspective challenges. We thank all colleagues for their support of this issue of the EJC conference, especially the program committee, the organising committee, and the programme coordination team. The long and the short papers presented in the conference are revised after the conference and published in the Series of “Frontiers in Artificial Intelligence” by IOS Press (Amsterdam). The books “Information Modelling and Knowledge Bases” are edited by the Editing Committee of the conference. We believe that the conference will be productive and fruitful in the advance of research and application of information modelling and knowledge bases. Bernhard Thalheim Hannu Jaakkola Yasushi Kiyok

Antenna theory in resonating systems derived from fundamental electromagnetism

In der vorliegenden Arbeit werden Konzepte der Antennentheorie mit denen der Mikrowellentheorie verkn¨upft, um eine “Antennentheorie innerhalb resonierender Systeme” zu formulieren. Resonierende Systeme sind in diesem Zusammenhang als r¨aumliche Umgebungen definiert, innerhalb derer sich elektromagnetische Resonanzen (“stehende Wellen”) ausbilden k¨onnen. Eine Antennentheorie innerhalb resonierender Systeme bietet einen geeigneten Rahmen zur Modellierung innerer Probleme der elektromagnetischen Vertr¨aglichkeit. Diese Modellierung beinhaltet haupts¨ achlich die Untersuchung der Wechselwirkung von Antennen, wobei elektromagnetische St¨orquellen durch sendende Antennen und elektromagnetische St¨orsenken durch empfangende Antennen repr¨asentiert werden. Unsere Vorgehensweise orientiert sich an den folgenden drei Fragestellungen:1. Welche Gleichungen bestimmen das Verhalten von Antennen innerhalb resonierender Systeme (physikalische Modellbildung und mathematische Formulierung)?2. Welche mathematischen Methoden sind anzuwenden, um diese Gleichungen hinreichend genau und schnell auswerten zu k¨onnen (analytische und numerische L¨osungsverfahren)?3. Welche Schlussfolgerungen lassen sich aus den gewonnenen L¨osungen ziehen (physikalische Interpretation und technische Anwendung)?Um auf diese Fragestellungen ad¨aquat eingehen zu k¨onnen, ist die Kenntnis der grundlegenden Konzepte der klassischen Elektrodynamik unabdingbar. Diese Konzepte werden in Kapitel 1 vollst¨andig eingef¨uhrt und interpretiert. Die gew¨ahlte Darstellung ist als Kombination von Maxwellscher Axiomatik und eichtheoretischer Beschreibung origin¨ar. Eine wichtige Konsequenz ist die Identifikation der zwei komplement¨aren Arten von Singularit¨aten des elektromagnetischen Feldes, welche durch Coulomb-Singularit¨aten und elektromagnetische Resonanzen gegeben sind. Entsprechend lassen sich elektromagnetische Felder in Coulomb-Felder und Strahlungsfelder unterteilen. F¨ ur die in praktischen Anwendungen auftretenden elektromagnetischen Felder ist eine exakte Aufspaltung in diese beiden Feldanteile in der Regel nicht m¨oglich. Diese untrennbare Verkn¨upfung von Coulomb-Anteilen und Strahlungsanteilen ist der haupts¨ achliche Grund f¨ ur die bei der Formulierung und Anwendung einer Antennentheorie in resonierenden Systemen auftretenden Schwierigkeiten. &nbsp

Energy: A continuing bibliography with indexes, issue 17

This bibliography lists 1292 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1978 through March 31, 1978