TY - CONF AU - Groenewegen, Luuk AU - Engels, Gregor ID - 8266 T2 - Proceedings of the 4th European Workshop on Software Process Technology (EWSPT 1995), Noordwijkerhout (The Netherlands) TI - Coordination by Behavioural Views and Communication Patterns VL - 913 ER - TY - CONF AB - Based on a categorical semantics that has been developed for typed graph grammars we uses colimits (pushouts) to model composition and (reverse) graph grammar morphisms to describe refinements of typed graph grammars. Composition of graph grammars w.r.t. common subgrammars is shown to be compatible with the semantics, i.e. the semantics of the composed grammar is obtained as the composition of the semantics of the component grammars. Moreover, the structure of a composed grammar is preserved during a refinement step in the sense that compatible refinements of the components induce a refinement of the composition. The concepts and results are illustrated by an example. AU - Corradini, Andrea AU - Heckel, Reiko ID - 8267 T2 - Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy) TI - A Compositional Approach to Structuring and Refinement of Typed Graph Grammars VL - 2 ER - TY - CONF AB - The overall aim of this paper is a proposal how to bridge the gap between formal specification techniques developed in research projects and semi--formal or informal specifications used in industrial practice. The main idea to overcome these problems is to develop graphical support for formal methods in order to increase acceptance by practitioners and to provide means for integration of formal and semi--formal methods. More specifically suitable concepts will be developed to combine algebraic specifications, Petri Nets, and Graph Grammars with each other and with distinguished graphical components to be used by industrial partners. AU - Bardohl, Bernhard AU - Bardohl, Roswitha AU - Castro, Paulo AU - Ehrig, Hartmut AU - Heckel, Reiko AU - Ribeiro, Leila AU - Nunes, Daltro AU - Martini, Alfio ID - 8268 T2 - Proceedings of the 3rd German-Brazilian Workshop on Information Technology (1995), Berlin (Germany) TI - GRAPHIT: Graphical Support and Integration of Formal and Semiformal Methods for Software Specification and Development VL - 26 ER - TY - CONF AB - Currently existing graph grammar-based specification languages have serious problems with supporting any kind of “specification-in-the-large” activities. More precisely, they have deficiencies with respect to modeling hierarchical data structures or specifying meta activities like manipulation of graph schemata. Furthermore, already proposed graph grammar module concepts are still too abstract to be useful in practice. Our contribution addresses these problems by introducing a new hierarchical graph data model with an infinite number of schema, meta-schema, etc. layers. It forms the base for a forthcoming concrete modular graph grammar specification language where in addition information hiding aspects like explicit export and import interfaces are expressible. AU - Engels, Gregor AU - Schürr, Andy ID - 8269 T2 - Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy) TI - Encapsulated Hierarchical Graphs, Graph Types, and Meta Types ER - TY - CONF AU - Heckel, Reiko AU - Wagner, Annika ID - 8270 T2 - Proceedings of the Joint COMPUGRAPH/SEMAGRAPH Workshop on Graph Rewriting and Computation (SEGRAGRA 1995), Volterra (Italy) TI - Ensuring Consistency of Conditional Graph Grammars - A constructive Approach VL - 2 ER - TY - CHAP AU - Kremer, H.-Hugo ED - Braukmann, U. ED - Diettrich, A. ED - Kremer, H.-H. ED - Sloane, P.F.E. ED - Stickling, E. ID - 8354 T2 - Meisterprüfung - Lernen für die Praxis - Unternehmensführung 1 TI - Existenzgründung ER - TY - JOUR AB - In an array of coupled oscillators, synchronous chaos may occur in the sense that all the oscillators behave identically although the corresponding motion is chaotic. When a parameter is varied this fully symmetric dynamical state can lose its stability, and the main purpose of this paper is to investigate which type of dynamical behavior is expected to be observed once the loss of stability has occurred. The essential tool is a classification of Lyapunov exponents based on the symmetry of the underlying problem. This classification is crucial in the derivation of the analytical results but it also allows an efficient computation of the dominant Lyapunov exponent associated with each symmetry type. We show how these dominant exponents determine the stability of invariant sets possessing various instantaneous symmetries, and this leads to the idea of symmetry breaking bifurcations of chaotic attractors. Finally, the results and ideas are illustrated for several systems of coupled oscillators. AU - Aston, Philip J. AU - Dellnitz, Michael ID - 16510 JF - International Journal of Bifurcation and Chaos SN - 0218-1274 TI - Symmetry Breaking Bifurcations of Chaotic Attractors ER - TY - JOUR AU - Dellnitz, M AU - Heinrich, C ID - 16532 JF - Nonlinearity SN - 0951-7715 TI - Admissible symmetry increasing bifurcations ER - TY - JOUR AU - Dellnitz, M AU - Melbourne, I ID - 16542 JF - Nonlinearity SN - 0951-7715 TI - A note on the shadowing lemma and symmetric periodic points ER - TY - JOUR AU - Dellnitz, Michael AU - Field, Michael AU - Golubitsky, Martin AU - Ma, Jun AU - Hohmann, Andreas ID - 16550 JF - International Journal of Bifurcation and Chaos SN - 0218-1274 TI - Cycling Chaos ER - TY - JOUR AB - Spiral patterns have been observed experimentally, numerically, and theoretically in a variety of systems. It is often believed that these spiral wave patterns can occur only in systems of reaction–diffusion equations. We show, both theoretically (using Hopf bifurcation techniques) and numerically (using both direct simulation and continuation of rotating waves) that spiral wave patterns can appear in a single reaction–diffusion equation [ in u(x, t)] on a disk, if one assumes "spiral" boundary conditions (ur = muθ). Spiral boundary conditions are motivated by assuming that a solution is infinitesimally an Archimedian spiral near the boundary. It follows from a bifurcation analysis that for this form of spirals there are no singularities in the spiral pattern (technically there is no spiral tip) and that at bifurcation there is a steep gradient between the "red" and "blue" arms of the spiral. AU - Dellnitz, Michael AU - Golubitsky, Martin AU - Hohmann, Andreas AU - Stewart, Ian ID - 16551 JF - International Journal of Bifurcation and Chaos SN - 0218-1274 TI - Spirals in Scalar Reaction–Diffusion Equations ER - TY - JOUR AU - Breslauer, Dany AU - Czumaj, Artur AU - Dubhashi, Devdatt P. AU - Meyer auf der Heide, Friedhelm ID - 16566 JF - Information Processing Letters SN - 0020-0190 TI - Transforming comparison model lower bounds to the parallel-random-access-machine ER - TY - CHAP AU - Golubitsky, Martin AU - Marsden, Jerrold AU - Stewart, Ian AU - Dellnitz, Michael ID - 16611 SN - 9780821803264 T2 - Normal Forms and Homoclinic Chaos TI - The constrained Liapunov-Schmidt procedure and periodic orbits ER - TY - CHAP AU - Meyer auf der Heide, Friedhelm AU - Vöcking, Berthold ID - 16704 SN - 0302-9743 T2 - STACS 95 TI - A packet routing protocol for arbitrary networks ER - TY - CHAP AU - Czumaj, Artur AU - Meyer auf der Heide, Friedhelm AU - Stemann, Volker ID - 16705 SN - 0302-9743 T2 - Lecture Notes in Computer Science TI - Shared memory simulations with triple-logarithmic delay ER - TY - CONF AU - Meyer auf der Heide, Friedhelm AU - Storch, Martin AU - Wanka, Rolf ID - 16706 SN - 0897917170 T2 - Proceedings of the seventh annual ACM symposium on Parallel algorithms and architectures - SPAA '95 TI - Optimal trade-offs between size and slowdown for universal parallel networks ER - TY - CONF AU - Czumaj, Artur AU - Meyer auf der Heide, Friedhelm AU - Stemann, Volker ID - 16707 SN - 0818669152 T2 - Proceedings Third Israel Symposium on the Theory of Computing and Systems TI - Improved optimal shared memory simulations, and the power of reconfiguration ER - TY - CHAP AU - Meyer auf der Heide, Friedhelm AU - Westermann, Matthias ID - 16717 SN - 0302-9743 T2 - Graph-Theoretic Concepts in Computer Science TI - Hot-potato routing on multi-dimensional tori ER - TY - CHAP AU - Bäumker, Armin AU - Dittrich, Wolfgang AU - Meyer auf der Heide, Friedhelm ID - 16874 SN - 0302-9743 T2 - Lecture Notes in Computer Science TI - Truly efficient parallel algorithms: c-optimal multisearch for an extension of the BSP model ER - TY - JOUR AU - Platzner, Marco AU - Rinner, Bernhard AU - Weiss, Reinhold ID - 10610 JF - J.UCS Journal of Universal Computer Science TI - Exploiting Parallelism in Constraint Satisfaction for Qualitative Simulation VL - 12 ER -