Bücher veröffentlicht von Springer Netherlands

John Lythgoe was one of the pioneers of the 'Ecology of Vision', a subject that he ably delineated in his classic and inspirational book published some 20 years ago [1]. At heart, the original book aimed generally to identify inter-relationships between vision, animal behaviour and the environment. John Lythgoe excelled at identifying the interesting 'questions' in the ecology of an animal that fitted the 'answers' presented by an analysis of the visual system. Over the last twenty years, however, since Lythgoe's landmark publication, much progress has been made and the field has broadened considerably. In particular, our understanding of the 'adaptive mechanisms' underlying the ecology of vision has reached considerable depths, extending to the molecular dimension, partly as a result of development and application of new techniques. This complements the advances made in parallel in clinically oriented vision research [2]. The current book endeavours to review the progress made in the ecology of vision field by bringing together many of the major researchers presently active in the expanded subject area. The contents deal with theoretical and physical considerations of light and photoreception, present examples of visual system structure and function, and delve into aspects of visual behaviour and communi- cation. Throughout the book, we have tried to emphasise one of the major themes to emerge within the ecology of vision: the high degree of adaptability that visual mechanisms are capable of undergoing in response to diverse, and dynamic, environments and behaviours.

The contributions in this book were presented at the sixth international symposium on Advances in Robot Kinematics organised in June/July 1998 in Strobl/Salzburg in Austria. The preceding symposia of the series took place in Ljubljana (1988), Linz (1990), Ferrara (1992), Ljubljana (1994), and Piran (1996). Ever since its first event, ARK has attracted the most outstanding authors in the area and managed to create a perfect combination of professionalism and friendly athmosphere. We are glad to observe that, in spite of a strong competition of many international conferences and meetings, ARK is continuing to grow in terms of the number of participants and in terms of its scientific impact. In its ten years, ARK has contributed to develop a remarkable scientific community in the area of robot kinematics. The last four symposia were organised under the patronage of the International Federation for the Theory of Machines and Mechanisms -IFToMM. interest to researchers, doctoral students and teachers, The book is of engineers and mathematicians specialising in kinematics of robots and mechanisms, mathematical modelling, simulation, design, and control of robots. It is divided into sections that were found as the prevalent areas of the contemporary kinematics research. As it can easily be noticed, an important part of the book is dedicated to various aspects of the kinematics of parallel mechanisms that persist to be one of the most attractive areas of research in robot kinematics.

1. BASIC CONCEPTS OF INTERACTIVE THEOREM PROVING Interactive Theorem Proving ultimately aims at the construction of powerful reasoning tools that let us (computer scientists) prove things we cannot prove without the tools, and the tools cannot prove without us. Interaction typi- cally is needed, for example, to direct and control the reasoning, to speculate or generalize strategic lemmas, and sometimes simply because the conjec- ture to be proved does not hold. In software verification, for example, correct versions of specifications and programs typically are obtained only after a number of failed proof attempts and subsequent error corrections. Different interactive theorem provers may actually look quite different: They may support different logics (first-or higher-order, logics of programs, type theory etc.), may be generic or special-purpose tools, or may be tar- geted to different applications. Nevertheless, they share common concepts and paradigms (e.g. architectural design, tactics, tactical reasoning etc.). The aim of this chapter is to describe the common concepts, design principles, and basic requirements of interactive theorem provers, and to explore the band- width of variations. Having a 'person in the loop', strongly influences the design of the proof tool: proofs must remain comprehensible, - proof rules must be high-level and human-oriented, - persistent proof presentation and visualization becomes very important.

This book is based mainly on invited and offered papers presented at the Second International Symposium on Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures held at University College, Cork, Ireland in September 1996, with additional invited papers. The First International Symposium on Bacterial and Bacteria-like Contaminants of Plant Tissue Cultures was held at the same venue in 1987 and was published as Acta Horticulturae volume 225, 1988. In the intervening years there have been considerable advances in both plant disease diagnostics and in the development of structured approaches to the management of disease and microbial contamination in micropropagation. These approaches have centred on attempts to separate, spatially, the problems of disease transmission and laboratory contamination. Disease-control is best achieved by establishing pathogen-free cultures while laboratory contamination is based on subsequent good working practice. Control of losses due to pathogens and microbial contamination in vitro addresses, arguably, the most importance causes of losses in the industry; nevertheless, losses at and post establishment can also be considerable due to poor quality microplants or micro-shoots. In this symposium, a holistic approach to pathogen and microbial contamination control is evident with the recognition that micropropagators must address pathogen and microbial contamination in vitro, and diseases and microplant failure at establishment. There is increasing interest in establishing beneficial bacterial and mycorrhizal association with microplants in vitro and in vivo.

This book contains the courses given at the Fourth School on Statistical Physics and Cooperative Systems held at Santiago, Chile, from 12th to 16th December 1994. This School brings together scientists working on subjects related to recent trends in complex systems. Some of these subjects deal with dynamical systems, ergodic theory, cellular automata, symbolic and arithmetic dynamics, spatial systems, large deviation theory and neural networks. Scientists working in these subjects come from several aeras: pure and applied mathematics, non linear physics, biology, computer science, electrical engineering and artificial intelligence. Each contribution is devoted to one or more of the previous subjects. In most cases they are structured as surveys, presenting at the same time an original point of view about the topic and showing mostly new results. The expository text of Roberto Livi concerns the study of coupled map lattices (CML) as models of spatially extended dynamical systems. CML is one of the most used tools for the investigation of spatially extended systems. The paper emphasizes rigorous results about the dynamical behavior of one dimensional CML; i.e. a uniform real local function defined in the interval [0,1], interacting with its nearest neighbors in a one dimensional lattice.

Molecular magnetism is a new field of research dealing with the synthesis and study of the physical properties of molecular assemblies involving open-shell units. It is essentially interdisciplinary, joining together organic, organometallic and inorganic chemists, as well as theoreticians, physicists and materials scientists.At the core of research into molecular magnetism lie design and synthesis of new molecular assemblies exhibiting bulk properties such as long-range magnetic ordering or bistability with an hysteresis effect, which confers a memory effect on the system. In such terms, magnetism may be considered a supramolecular function.The first eight contributions to this volume present the state of the art in organic supramolecular chemistry, emphasising interlocked systems and molecular trees. The following six articles are devoted to molecular materials constructed from organic radicals and transition metal units. Molecular bistability is then focused on, followed by metal-organic and coordination magnetic materials. A new approach to nano-sized particles closes the work.

One of the first priority areas among joint East/West research programs is the rational use of natural resources and sustainable development of regions. In the boreal zone of North America and Eurasia forests are economically very important and, at the same time highly vulnerable to disturbances. Because of its size and ecological functions the boreal forest zone and its most dynamic disturbance factor - fire - play an important role in ecosystem processes on global scale. Interest within the global change research community in Northern Eurasia (Fennoscandia, European Russia, Siberia, and the Far East of Russia) has grown dramatically in the last few years. It is a vast area about which very little is known. It is a region where temperature rise due to anthropogenic climate forcing is predicted to be the greatest, and where the consequent feedbacks to the atmosphere are potentially large. In addition, it is poised to undergo rapid economic development, which may lead to large and significant changes to its land cover. Much of this interest in Northern Eurasia, as in the high latitude regions in general, is centerd on its role in the global carbon cycle, which is likely to be significantly affected under global change. New research initiatives between Western and Eastern countries have been designed to address a series of phenomena, problems and management solutions.