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Principles of Data Security (Foundations of Computer Science)
by Ernst L. LeissWith the greatly increased use of electronic media for processing and storing data, data security became an important practical issue. This is especially true for the extensively shared and distributed systems which are more and more being accepted in commercial operations. Essen tially, the problem is that of protecting data, including all the impli cations which this has to the end user as well as the systems or database designer. However, usually the term data security refers to protection by technical, i.e., computer science specific, means; if one wants to in clude issues such as physical security, how to select the group of people who should have authority to perform certain operations, etc., the term computer security is more appropriate. The object of this book is to provide technical solutions to (facets of) the problem of achieving data security. The reader who hopes to find clever recipes which allow circumventing protection mechanisms will, however, be sadly disappointed. In fact, we deliberately kept the presentation of the material at a fairly general level. While the short term benefit of such an approach may be somewhat smaller, we feel that without a thorough understanding of the fundamental issues and problems in data security there will never be secure systems. True, peo ple probably always considered certain security aspects when designing a system. However, an integrated approach is absolutely imperative.
Programmiersprachen und Programmentwicklung: 7. Fachtagung veranstaltet vom Fachausschuß 2 der GI München, 9./10. März 1982 (Informatik-Fachberichte #53)
by H. Wössner
A Programming Approach to Computability (Monographs in Computer Science)
by A.J. Kfoury Robert N. Moll Michael A. ArbibComputability theory is at the heart of theoretical computer science. Yet, ironically, many of its basic results were discovered by mathematical logicians prior to the development of the first stored-program computer. As a result, many texts on computability theory strike today's computer science students as far removed from their concerns. To remedy this, we base our approach to computability on the language of while-programs, a lean subset of PASCAL, and postpone consideration of such classic models as Turing machines, string-rewriting systems, and p. -recursive functions till the final chapter. Moreover, we balance the presentation of un solvability results such as the unsolvability of the Halting Problem with a presentation of the positive results of modern programming methodology, including the use of proof rules, and the denotational semantics of programs. Computer science seeks to provide a scientific basis for the study of information processing, the solution of problems by algorithms, and the design and programming of computers. The last 40 years have seen increasing sophistication in the science, in the microelectronics which has made machines of staggering complexity economically feasible, in the advances in programming methodology which allow immense programs to be designed with increasing speed and reduced error, and in the develop ment of mathematical techniques to allow the rigorous specification of program, process, and machine.
Programming in Modula-2
by N. WirthThis text is an introduction to programming in general, and a manual for programming with the language Modula-2 in particular. It is oriented primarily towards people who have already acquired some basic knowledge of programming and would like to deepen their understanding in a more structured way. Nevertheless, an introductory chapter is included for the benefit of the beginner, displaying in a concise form some of the fundamental concepts of computers and their programming. The text is therefore also suitable as a self-contained tutorial. The notation used is Modula-2, which lends itself well for a structured approach and leads the student to a working style that has generally become known under the title of structured programming. As a manual for programming in Modula-2, the text covers practically all facilities of that language. Part 1 covers the basic notions of the variable, expression, assignment, conditional and repetitive statement, and array data structure. Together with Part 2 which introduces the important concept of the procedure or subroutine, it contains essentially the material commonly discussed in introductory programming courses. Part 3 concerns data types and structures and constitutes the essence of an advanced course on programming. Part 4 introduces the notion of the module, a concept that is fundamental to the design of larger programmed systems and to programming as team work. The most commonly used utility programs for input and output are presented as examples of modules. And fmally, Part 5 covers facilities for system programming, device handling, and multiprogramming.
Programmorganisation und indirektes Programmieren für AOS-Rechner (Anwendung programmierbarer Taschenrechner #11)
by Arnim Tölke
Real Time Programming 1981: Proceedings of the IFAC/IFIP Workshop, Kyoto, Japan, 31 August - 2 September 1981
by T. HasegawaAnnual Review in Automatic Programming, Volume 11: Real Time Programming 1981 contains the proceedings of the IFAC/IFIP Workshop held in Kyoto, Japan on August 31 - September 2, 1981. Organized into 18 chapters, this book begins with a discussion on advances and trends in distributed control systems. Subsequent chapters explore the application and technology of industrial computers in Japan; on-line system changeover using a virtual machine system; a debugging tool for real time software; and program fall-back method in real time systems. Some other chapters address file design of small real time computer system; development of a distributed operating system kernel for real time applications; and evaluation of pipelined common processor in distributed processing system.
Rechnerunterstützte Gestaltung ortsgebundener Montagearbeitsplätze, dargestellt am Beispiel kleinvolumiger Produkte (IPA-IAO - Forschung und Praxis #65)
by E. Haller
Scattering Theory of Waves and Particles (Theoretical and Mathematical Physics)
by R.G. NewtonMuch progress has been made in scattering theory since the publication of the first edition of this book fifteen years ago, and it is time to update it. Needless to say, it was impossible to incorporate all areas of new develop ment. Since among the newer books on scattering theory there are three excellent volumes that treat the subject from a much more abstract mathe matical point of view (Lax and Phillips on electromagnetic scattering, Amrein, Jauch and Sinha, and Reed and Simon on quantum scattering), I have refrained from adding material concerning the abundant new mathe matical results on time-dependent formulations of scattering theory. The only exception is Dollard's beautiful "scattering into cones" method that connects the physically intuitive and mathematically clean wave-packet description to experimentally accessible scattering rates in a much more satisfactory manner than the older procedure. Areas that have been substantially augmented are the analysis of the three-dimensional Schrodinger equation for non central potentials (in Chapter 10), the general approach to multiparticle reaction theory (in Chapter 16), the specific treatment of three-particle scattering (in Chapter 17), and inverse scattering (in Chapter 20). The additions to Chapter 16 include an introduction to the two-Hilbert space approach, as well as a derivation of general scattering-rate formulas. Chapter 17 now contains a survey of various approaches to the solution of three-particle problems, as well as a discussion of the Efimov effect.
Selected Papers
by Calvin C. ElgotCal Elgot was a very serious and thoughtful researcher, who with great determi nation attempted to find basic explanations for certain mathematical phenomena as the selection of papers in this volume well illustrate. His approach was, for the most part, rather finitist and constructivist, and he was inevitably drawn to studies of the process of computation. It seems to me that his early work on decision problems relating automata and logic, starting with his thesis under Roger Lyndon and continuing with joint work with Biichi, Wright, Copi, Rutledge, Mezei, and then later with Rabin, set the stage for his attack on the theory of computation through the abstract treatment of the notion of a machine. This is also apparent in his joint work with A. Robinson reproduced here and in his joint papers with John Shepherdson. Of course in the light of subsequent work on decision problems by Biichi, Rabin, Shelah, and many, many others, the subject has been placed on a completely different plane from what it was when Elgot left the area. But I feel that his papers, results-and style-were very definitely influential at the time and may well have altered the course of the investigation of these problems. As Sammy Eilenberg explains, the next big influence on Elgot's thinking was category theory, which gave him a way of expressing his ideas in a sharply algebraic manner. The joint book with Eilenberg is one illustration of this influence.
Selected Writings on Computing: A personal Perspective (Monographs in Computer Science)
by Edsger W. DijkstraSince the summer of 1973, when I became a Burroughs Research Fellow, my life has been very different from what it had been before. The daily routine changed: instead of going to the University each day, where I used to spend most of my time in the company of others, I now went there only one day a week and was most of the time -that is, when not travelling!- alone in my study. In my solitude, mail and the written word in general became more and more important. The circumstance that my employer and I had the Atlantic Ocean between us was a further incentive to keep a fairly complete record of what I was doing. The public part of that output found its place in what became known as "the EWD series", which can be viewed as a form of scientific correspondence, possible since the advent of the copier. (That same copier makes it hard to estimate its actual distribution: I myself made about two dozen copies of my texts, but their recipients were welcome to act as further nodes of the distribution tree. ) The decision to publish a se1ection from the EWD series in book form was at first highly embarrassing, but as the months went by I got used to the idea. As soon as some guiding principles had been adopted -preferably not published elsewhere, as varied and as representative as possible, etc.
Simulationstechnik: 1. Symposium Simulationstechnik Erlangen, 26. – 28. April 1982 Proceedings (Informatik-Fachberichte #56)
by M. GollerDas erste Symposium Simulationstechnik wurde vom 26.- 28.April 1982 in Erlangen veranstaltet vom Lehrstuhl IV des Instituts für Math- matische Maschinen und Datenverarbeitung (IMMD) der Universität Erlangen - Nürnberg. Die 56 Beiträge des vorliegenden Bandes enthalten die Hauptvorträge, die Beschreibung der beim Symposium verfügbaren Simulationsmodelle, und die Vorträge der Fachgruppen Methodologie, Modellbau, Medizin, Regelungstechnik, Technische Anwendungen, Simulationsrechner und Simulationssprachen. Ein breites Einsatzgebiet der Simulation wird damit erfasst, wenn gleich es auf der ersten Veranstaltung dieser Art in Deutschland noch nicht zu erwarten war, alle Anwendungsgebiete des relativ neuen Verfahrens aufzeigen zu können. Ich möchte allen danken, die dieses Symposium besucht und erfolgreich gestaltet haben. Den Vortragenden danke ich für die Beiträge und ihre Zusammenarbeit im Hinblick auf diesen Bericht über das Symposium. Den Mitarbeitern des Lehrstuhls IV, besonders Frau E. Roth und Herrn R. Rimane danke ich für die große Hilfe bei der Organisation der Veranstaltung. Dem Springer-Verlag danke ich für die freundliche Unterstützug bei der Erstellung des Tagungsbandes. Erlangen, im Juli 1982 Manuel Goller INHALTSVERZEICHNIS EINLEITUNG Das 1. Symposium Simulationstechnik B. Schmidt ................................. .
SMS — A Program Package for Simulation and Gaming of Stochastic Market Processes and Learning Behavior (Lecture Notes in Economics and Mathematical Systems #202)
by U. Witt J. Perske
Software-Qualitätssicherung: Testen im Software-Lebenszyklus (Programm Angewandte Informatik)
by Paul SchmitzWenn Fehler in Software-Produkten während des Betriebs auftreten, ist dies nicht aus schließlich darauf zurückzuführen, daß in der Entwicklung zu wenig getestet worden ist. Durch verschiedene Umfragen konnten Anteile des Testaufwands (einschlißlich Pilottest) am Gesamtaufwand der Software-Entwicklung von bis zu 70 % ermittelt werden (siehe Abb. 0-1). Durchschnittlich kann man davon ausgehen daß zwischen 30 % und 50 % des Gesamtaufwands der Software-Entwicklung für Testen aufgewendet werden. Umfrage Testaufwand (U1) 20-30 % bzw. 20-40 % (U2) 60-70% inklusive Pilottest (U3) o 30-50 % für Anwendungssoftware o 30-40 % für Systemsoftware Abb. 0-1: Aufwand des Testens als Anteil des gesamten Entwicklungsaufwands /BONS82c/ Ul: /SCHM78/; U2: /SCHM80a/; U3: /SCHM8l/ Sofern der Aufwand für Testen nicht zu gering ist, sondern vielfach als zu hoch bezeichnet wird, ergibt sich zwangsläufig die Frage nach den Ursachen für die dennoch häufig be mängelte Qualität von Software-Produkten. Ursachen sind vielfach, daß zwar eine Viel zahl von Tests durchgeführt werden, jedoch überwiegend zum falschen Zeitpunkt und mit der falschen Vorgehensweise. Vorhandene Fehler werden zu spät gefunden, d. h. später als eigentlich möglich, wodurch zwangsläufig Folgefehler in den Entwicklungsschritten entstehen. Darüber hinaus werden teilweise Methoden verwendet, die nicht effizient sind. So werden z. B. für den Abnahmetest über einen bestimmten Zeitraum ausschließlich Parallelläufe durchgeführt, wobei von vornherein sicher ist, daß eine Vielzahl von Normal fällen verarbeitet werden, aber die - immer wieder zu Fehlverhalten führenden - Grenz werte oder Falschwerte nicht systematisch einbezogen werden.
Standardprogramme der Netzwerkanalyse für BASIC-Taschencomputer (Anwendung programmierbarer Taschenrechner #18)
by Dieter Lange
Successful Business Computing
by M. TampoeSuccessful Business Computing offers a practical guide to the selection and use of a computer system. It helps identify those factors that need to be assessed in buying computer equipment and the associated computing instructions, called computer programs or software. It is a management manual and not a technical treatise on computing theory, or advanced computing. The book is organized into three main parts. Part 1 helps the reader to recognize the symptoms and assess needs. It identifies some of the reasons which prompt the purchase of computer systems and the areas of the organization which can benefit. It explains a method of pinpointing the specific application areas. It emphasizes the need for a computing policy within the organization; specifies some significant policy issues; and identifies sources of external help. Part 2 guides the reader through the buying cycle, identifying the major activities and providing guidelines for the evaluation of the systems proposed. Part 3 explains the constituents of a computer system and provides a glossary of terms. This book is intended for the businessman or executive looking for guidelines on how best to handle the task of acquiring a computer system. It can also provide students with an introduction to the application of computers and computer systems in business and commerce.
System zur inversen Bildtransformation mit elektrooptischen Mitteln (Forschungsberichte des Landes Nordrhein-Westfalen #3091)
by Hans Jörg Tafel
ADA An Introduction: Ada Reference Manual (July 1980)
by H. LedgardIf Charles Babbage is to be regarded as the father of modern day computer technology, then surely the Countess Augusta Ada Lovelace, after whom this new language is named, must be remembered as its midwife. It was she, the daughter of England's poet Lord Byron, who translated the work of the Italian mathematician L.F. Menabrea, attaching her own scientific commentaries on the dissimilarities between the difference engine and .the analytical engine. It was Lady Lovelace, the great lady of computers, who delivered the notes and loosely organized writings of Babbage, with her own invaluable amendments, to a world not quite ready to receive them. The Ada language effort has employed hundreds, if not thousands, of minds and a healthy sum of money since its conception. Ada was fostered by the High Order Language Working Group (HOLWG), chartered by the U.S. Department of Defense in January of 1975 with the overall objective of developing a systematic approach to improved use of software by the military. One would think the Pentagon an unlikely foster parent for a new computer language. Regardless of its lineage, the question that begs asking is, of course-Why? The answer is by no means a simple one, but some brief background may help to clarify the matter. At present, the Department of Defense is the largest software consumer on earth, employing roughly 400 different computer languages and dialects. The situation, some have commented, is at best untidy.
Algebra für Informatiker
by Hans Kaiser Rainer Mlitz Gisela ZeilingerDas Kernstück des vorliegenden Buches entstand aus einer einsemestrigen Vor lesung gleichen Namens, die die Autoren seit mehreren Studienjahren an der Technischen Universität Wien betreuen und die von R.Mlitz ausgearbeitet wurde. Es erschien den Autoren notwendig bzw. zweckmäßig dieses Kernstück zu ergänzen durch lineare Algebra - die an der TU Wien getrennt vorgetragen wird - und graphentheoretische Grundbegriffe. Die von den Autoren gewonnenen Erfahrungen haben die vom üblichen Schema abweichenden didaktischen Aspekte der Darstellung geprägt, deren Grundprinzip in der nachfolgenden Einleitung erläutert wird. Das Buch richtet sich zunächst an Studierende der Informatik zum Gebrauch neben entsprechenden Vorlesungen, zum Nachschlagen und Wiederholen. Darüber hinaus soll der Anwender angesprochen werden, der in dem Werk die wichtigsten algebraischen Methoden des Informatikers dargeboten findet. Die Darstellung beschränkt sich auf den mathematischen Hintergrund und dessen direkte Anwendung. Bezüglich eventueller technischer Realis;erungen sei auf die entsprechende Literatur verwiesen. Unser besonderer Dank gilt Frau E.Wiesenbauer und Frau H.Reinauer für die sorgfältig durchgeführten Schreibarbeiten, Herrn Mag.W.Nowak für die genaue Ausführung der Graphiken, sowie dem Springer-Verlag Wien für sein Entgegenkommen und die gute Zusammenarbeit.