Bøger af Grzegorz Rozenberg

L systems are language-theoretic models for developmentalbiology. They wereintroduced in 1968 by Aristid Lindenmayer(1925-1989) and have proved to be among the most beautifulexamples of interdisciplinary science, where work in onearea induces fruitful ideas and results in other areas. Lsystemsare based on relational and set-theoretic concepts,which are more suitable for the discrete and combinatorialstructures of biology than mathematical models based oncalculus or statistics. L systems have stimulated new worknot only in the realistic simulation of developing organismsbut also in the theory of automata and formal languages,formal power series, computer graphics, and combinatorics ofwords. This book contains research papers by almost all leadingauthorities and by many of the most promising youngresearchers in the field. The 28 contributions are organizedin sections on basic L systems, computer graphics, graphgrammars and map L systems, biological aspects and models,and variations and generalizations of L systems. Theintroductory paper by Lindenmayer and J}rgensen was writtenfor a wide audience and is accessible to the non-specialistreader. The volume documents the state of the art in the theory of Lsystems and their applications. It will interest researchersand advanced students in theoretical computer science anddevelopmental biology as well as professionals in computergraphics.

Theareaofgraphtransformationoriginatedinthelate1960sunderthename "e;graph grammars"e; - the main motivation came from practical considerations concerning pattern recognition and compiler construction. Since then, the list of areas which have interacted with the development of graph transformation has grown impressively. The areas include: software speci?cation and development, VLSI layout schemes, database design, modeling of concurrent systems, m- sively parallel computer architectures, logic programming, computer animation, developmentalbiology,musiccomposition,distributedsystems,speci?cationl- guages, software and web engineering, and visual languages. As a matter of fact, graph transformation is now accepted as a fundamental computation paradigm where computation includes speci?cation, programming, and implementation. Over the last three decades the area of graph transfor- tion has developed at a steady pace into a theoretically attractive research ?eld, important for applications. Thisvolume consistsofpapersselectedfromcontributionsto the Sixth Int- national Workshop on Theory and Applications of Graph Transformation that took place in Paderborn, Germany, November 16-20, 1998. The papers und- went an additional refereeing process which yielded 33 papers presented here (out of 55 papers presented at the workshop). This collection of papers provides a very broad snapshot of the state of the art of the whole ?eld today. They are grouped into nine sections representing most active research areas. Theworkshopwasthe sixth in a seriesof internationalworkshopswhich take place every four years. Previous workshops were called "e;Graph Grammars and Their Application to Computer Science"e;. The new name of the Sixth Workshop re?ectsmoreaccuratelythecurrentsituation,whereboththeoryandapplication play an equally central role.

Molecular computing is a rapidly growing subarea of natural computing. On the one hand, molecular computing is concerned with the use of bio-molecules for the purpose of actual computations while, on the other hand, it attempts to understand the computational nature of molecular processes going on in living cells.The book presents a unique and authorative state-of-the-art survey on current research in molecular computing: 30 papers by leading researchers in the area are drawn together on the occasion of the 70th birthday of Tom Head, a pioneer in molecular computing. Among the topics addressed are molecular tiling, DNA self-assembly, splicing systems, DNA-based cryptography, DNA word design, gene assembly, and membrane computing.

As CMOS semiconductor technology strides towards billions of transistors on a single die new problems arise on the way. They are concerned with the - minishing fabrication process features, which a?ect for example the gate-to-wire delay ratio. They manifest themselves in greater variations of size and operating parameters of devices, which put the overall reliability of systems at risk. And, most of all, they have tremendous impact on design productivity, where the costs of utilizing the growing silicon 'real estate' rocket to billions of dollars that have to be spent on design, veri?cation, and testing. All such problems call for new - sign approaches and models for digital systems. Furthermore, new developments in non-CMOS technologies, such as single-electron transistors, rapid single-?- quantum devices, quantum dot cells, molecular devices, etc. , add extra demand for new research in system design methodologies. What kind of models and design methodologies will be required to build systems in all these new technologies? Answering this question, even for each particular type of new technology generation, is not easy, especially because sometimes it is not even clear what kind of elementary devices are feasible there. This problem is of an interdisciplinary nature. It requires an bridges between di?erent scienti?c communities. The bridges must be built very quickly, and be maximally ?exible to accommodate changes taking place in a logarithmic timescale.

Since their introduction nearly 40 years ago, research on Petri nets has diverged in many different directions. Various classes of Petri net, motivated either by theory or applications, with its own specific features and methods of analysis, have been proposed and studies in depth.These successful developments have led to a very heterogeneous landscape of diverse models, and this, in turn, has stimulated research on concepts and approaches that contribute to unifying and structuring the diverse landscape. This state-of-the-art survey presents the most relevant approaches to unifying Petri nets in a systematic and coherent way. The 14 chapters written by leading researchers are organized in topical sections on application-oriented approaches, unifying frameworks, and theoretical approaches.