DOCSLIB.ORG

A Lightweight Formal Method for the Prediction of Non-Functional System Properties

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Lightweight Formal Method for the Prediction of Non-Functional System Properties A Lightweight Formal Method for the Prediction of Non-Functional System Properties Der Technischen Fakultät der Universität Erlangen-Nürnberg zur Erlangung des Grades Doktor-Ingenieur vorgelegt von Jörg Barner Erlangen — 2005 Als Dissertation genehmigt von der Technischen Fakultät der Universität Erlangen-Nürnberg Tag der Einreichung: 20.06.2005 Tag der Promotion: 14.10.2005 Dekan: Prof. Dr.-Ing. Alfred Leipertz Berichterstatter: Prof. Dr. Fridolin Hofmann, Prof. Dr. Khalid Al-Begain Acknowledgments First of all, I would like to thank Prof. Dr. Fridolin Hofmann for supervising this dissertation and for the open environment he created together with Prof. Dr.-Ing. Wolfgang Schröder- Preikschat in our department which allowed me to finish this project. Furthermore, I am particularly grateful to Prof. Dr. Khalid Al-Begain, my co-promoter, whose interest in appli- cations and the encouraging feedback he gave were always a great pleasure. I owe a lot of thanks to Dr.-Ing. Gunter Bolch, my “Ana” research group leader for many inspiring discussions which helped me a lot to sharpen my thoughts on important issues and prevented me from losing my direction. Without the commitment that Björn Beutel and Patrick Wüchner exhibited during the preparation of their master theses some of the concepts presented in this dissertation would have remained purely theoretical. My former office mate Dr.-Ing. Michael Schröder proof-read various intermediate ver- sions of this dissertation. Together with him, Stephan Kösters supported me in the nerve- wracking final phase before submitting the thesis by doing some valuable last-minute proof- reading. It has been a lot of fun to work at the department for distributed systems and operat- ing systems with all the colleagues and students. The pleasant working atmosphere was extraordinary, and I will always remember my time there with happiness! Special acknow- ledgments go to Dr.-Ing. Uwe Linster who gave me the opportunity to participate in the interesting UnivIS project and to Dr.-Ing. Jürgen Kleinöder for his support concerning vari- ous funding and working contract issues. Finally, I would like to express my gratitude to my parents Ilsetraut and Klaus Barner for their continuous and loving support over all these years. Far away in “down under” Leonie, Christopher and Ellen Barner always kept their fingers crossed for me and my project — Thank you all! Abstract The goal of performance and reliability evaluation during the development of computer- based systems is to predict the compliance of the projected system with a set of non-func- tional requirements. As an example, consider the expected mean end-to-end delay of data packets in a communication network, which can be predicted on the basis of a stochas- tic model during the early conceptual design phase. A glance at the software engineering practice reveals that despite their high financial savings potential academic methods of per- formance evaluation are not applied on a large scale. Frequently quoted reasons for these findings are the cumbersome notation of some stochastic description techniques and the impractical presentation of the theoretical foundations. The successful application of per- formance evaluation methods thus remains reserved to a handful of well-educated experts. This phenomenon, termed insularity problem by some members of the academic perfor- mance evaluation community, can be regarded as a special case of the general problem of low formal method acceptance in industrial software development. The first formal meth- ods were developed by several computer scientists about 40 years ago with the ambitious goal to create programs which are proven to be correct by construction. Because of the quite revolutionary approach to programming and the inability of their developers to show that formal methods are appropriate to solve larger real-world problems they did not become widely accepted and used by the software engineering industry. A promising attempt to bridge this “industry-academia gap” was initiated in the early-mid 1990s with the advent of “lightweight” formal methods for the verification of functional system requirements, some of which could be applied successfully in industrial software development projects. The initial point of view which is adopted in this dissertation is to regard performance evaluation as a branch of requirements verification techniques which are applied during the development of software-based systems. Because of the similarities in the structure and the objectives of the methods in both areas, we assume that the transfer of the lightweight for- mal method concept to the area of performance evaluation will have a positive effect on the solution of the insularity problem. In order to corroborate this assumption, a new lightweight formal method for the prediction of nonfunctional system requirements is de- veloped within the scope of this thesis. The method consists of a formal description tech- nique which is based on a well-defined syntax and semantics. It enables the user to specify the system structure and behaviour, the interaction of the system with its enviroment as well as the interesting nonfunctional system requirements as a stochastic model on a high abstraction level. The syntax of our description language combines the advantages of the pragmatic network-oriented modelling paradigm with the succinctness of a pure textual notation. The evaluation of the system properties is carried out in a user-friendly man- ner by the automatic analysis of the model in the evaluation environment prototype which was implemented in the context of this thesis. In order to demonstrate the applicability of the method we present some detailed case studies from the area of communication systems (WLAN, GSM). The keynote of this dissertation is to promote the transfer of technology from academia to industry by the integration of formal methods for performance and reliability evaluation in the early phases of the software development process. i Parts of the material presented in this thesis has previously been published as: 1. Al-Begain, Khalid; Barner, Jörg; Bolch, Gunter; Zreikat, Aymen: The Performance and Reliability Modelling Language MOSEL-2 and its Applications. International Journal on Simulation: Systems, Science and Technology, 3(3 – 4)(66-80), 2002. 2. Barner, Jörg: Performance and reliability modelling with MOSEL-2. Tutorial. ASMTA- Track of the 17th European Simulation Multiconference: Foundations for Successful Modelling & Simulation (ESM’03), Nottingham Trent University, Nottingham, England, Juni 2003 3. Barner, Jörg; Bolch, Gunter: MOSEL-2: Modeling, Specification and Evaluation Lan- guage, Revision 2 . In: Sanders, William (Hrsg.): Proc. 13th International Conference on Modeling Techniques and Tools for Computer Performance Evaluation (Performance TOOLS 2003 Urbana-Champaign, Illinois, 2 - 5.9 2003). 2003, S. 222 – 230. ii Table of Contents 1. Introduction 1 1.1. Motivation . 1 1.2. Objectives . 4 1.3. Thesis Outline . 5 2. Software Engineering meets Performance Evaluation 9 2.1. SWE – Standardised Development Processes and Description Techniques . 9 2.1.1. Origins and Concepts of Software Engineering . 9 2.1.2. The Unified Modelling Language UML ...................... 11 2.1.3. Early System Verification — An Economic Motivation . 13 2.1.4. Requirements Verification using Formal Methods . 15 2.2. Performance Evaluation — Stochastic Modelling and Analysis Techniques . 19 2.2.1. Non-Functional System Properties . 20 2.2.2. Stochastic High-Level Modelling Formalisms . 24 2.3. The Roots of Stochastic Modelling . 32 3. The MOSEL-2 Lightweight Formal Method 41 3.1. “Explain by example” vs. “Explain by methodology” . 42 3.2. Methods and Formal Systems . 44 3.2.1. Syntax, Semantics and Formal Systems . 46 3.2.2. Properties of Formal Description Techniques . 49 3.2.3. Problems in Formal Method Application . 50 3.2.4. Practical Formal Methods: The Lightweight Approach . 52 3.3. The LWFM approach for Performance Evaluation . 54 3.3.1. MOSEL-2 methodology . 54 3.3.2. The MOSEL-2 formal framework . 57 3.4. Architecture of the MOSEL-2 LWFM . 58 3.4.1. Informality: The Real World . 60 3.4.2. Formalization: From Reality to Formal Specification . 60 3.4.3. What does it mean? Semantic Mapping . 61 3.4.4. The Mathematical Foundation: Stochastic Processes . 62 4. The MOSEL-2 Formal Description Technique 77 4.1. Fixing the Expressiveness: Core Language . 78 4.1.1. The node construct . 78 4.1.2. The rule construct . 78 iii Table of Contents 4.1.3. Constant and Parameter Declarations . 82 4.2. Advanced language constructs . 83 4.2.1. The loop construct . 83 4.2.2. COND and FUNC constructs . 86 4.2.3. Reward measure definition . 87 4.2.4. The rule preprocessor . 87 5. The MOSEL-2 Evaluation Environment 91 5.1. Structure and Application Flow . 91 5.2. A Simple Analysis Example . 95 6. Related Work 99 6.1. Related Tools and Languages . 99 6.2. A Comparative Assessment with MOSEL-2 ....................... 101 7. Case Studies 105 7.1. Modelling a single GSM/GPRS Cell with Delay Voice Calls . 105 7.1.1. Informal real-world system description . 105 7.1.2. Conceptual Model . 106 7.1.3. MOSEL-2 description . 107 7.1.4. System evaluation . 108 7.2. Performance Model of a WLAN-System . 110 7.2.1. System Architecture and Working Modes . 110 7.2.2. Conceptual Model . 113 7.2.3. MOSEL-2 description . 114 7.2.4. System evaluation . 117 7.2.5. Discussion . 117 8. Conclusion 119 8.1. A Retrospect . 119 8.2. Has the Goal been reached? . 121 8.3. Future Work . 122 Einleitung 129 Zusammenfassung 136 A. MOSEL-2 syntax reference 143 B. Using the MOSEL-2 environment 147 Bibliography 148 iv List of Figures 1.1. The “Industry-Academia” Gap . 4 2.1. UML 2.0 diagram types . 12 2.2. Requirements vs. cost of error correction . 14 2.3. Potential application areas of formal methods for requirements verification and example tools .
Load more

Recommended publications
  • Thomas Ströhlein's Endgame Tables: a 50Th Anniversary
    Thomas Ströhlein's Endgame Tables: a 50th Anniversary Article Supplemental Material The Festschrift on the 40th Anniversary of the Munich Faculty of Informatics Haworth, G. (2020) Thomas Ströhlein's Endgame Tables: a 50th Anniversary. ICGA Journal, 42 (2-3). pp. 165-170. ISSN 1389-6911 doi: https://doi.org/10.3233/ICG-200151 Available at http://centaur.reading.ac.uk/90000/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . Published version at: https://content.iospress.com/articles/icga-journal/icg200151 To link to this article DOI: http://dx.doi.org/10.3233/ICG-200151 Publisher: The International Computer Games Association All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online 40 Jahre Informatik in Munchen:¨ 1967 – 2007 Festschrift Herausgegeben von Friedrich L. Bauer unter Mitwirkung von Helmut Angstl, Uwe Baumgarten, Rudolf Bayer, Hedwig Berghofer, Arndt Bode, Wilfried Brauer, Stephan Braun, Manfred Broy, Roland Bulirsch, Hans-Joachim Bungartz, Herbert Ehler, Jurgen¨ Eickel, Ursula Eschbach, Anton Gerold, Rupert Gnatz, Ulrich Guntzer,¨ Hellmuth Haag, Winfried Hahn (†), Heinz-Gerd Hegering, Ursula Hill-Samelson, Peter Hubwieser, Eike Jessen, Fred Kroger,¨ Hans Kuß, Klaus Lagally, Hans Langmaack, Heinrich Mayer, Ernst Mayr, Gerhard Muller,¨ Heinrich Noth,¨ Manfred Paul, Ulrich Peters, Hartmut Petzold, Walter Proebster, Bernd Radig, Angelika Reiser, Werner Rub,¨ Gerd Sapper, Gunther Schmidt, Fred B.
    [Show full text]
  • The Advent of Recursion & Logic in Computer Science
    The Advent of Recursion & Logic in Computer Science MSc Thesis (Afstudeerscriptie) written by Karel Van Oudheusden –alias Edgar G. Daylight (born October 21st, 1977 in Antwerpen, Belgium) under the supervision of Dr Gerard Alberts, and submitted to the Board of Examiners in partial fulfillment of the requirements for the degree of MSc in Logic at the Universiteit van Amsterdam. Date of the public defense: Members of the Thesis Committee: November 17, 2009 Dr Gerard Alberts Prof Dr Krzysztof Apt Prof Dr Dick de Jongh Prof Dr Benedikt Löwe Dr Elizabeth de Mol Dr Leen Torenvliet 1 “We are reaching the stage of development where each new gener- ation of participants is unaware both of their overall technological ancestry and the history of the development of their speciality, and have no past to build upon.” J.A.N. Lee in 1996 [73, p.54] “To many of our colleagues, history is only the study of an irrele- vant past, with no redeeming modern value –a subject without useful scholarship.” J.A.N. Lee [73, p.55] “[E]ven when we can't know the answers, it is important to see the questions. They too form part of our understanding. If you cannot answer them now, you can alert future historians to them.” M.S. Mahoney [76, p.832] “Only do what only you can do.” E.W. Dijkstra [103, p.9] 2 Abstract The history of computer science can be viewed from a number of disciplinary perspectives, ranging from electrical engineering to linguistics. As stressed by the historian Michael Mahoney, different `communities of computing' had their own views towards what could be accomplished with a programmable comput- ing machine.
    [Show full text]
  • Edsger W. Dijkstra: a Commemoration
    Edsger W. Dijkstra: a Commemoration Krzysztof R. Apt1 and Tony Hoare2 (editors) 1 CWI, Amsterdam, The Netherlands and MIMUW, University of Warsaw, Poland 2 Department of Computer Science and Technology, University of Cambridge and Microsoft Research Ltd, Cambridge, UK Abstract This article is a multiauthored portrait of Edsger Wybe Dijkstra that consists of testimo- nials written by several friends, colleagues, and students of his. It provides unique insights into his personality, working style and habits, and his influence on other computer scientists, as a researcher, teacher, and mentor. Contents Preface 3 Tony Hoare 4 Donald Knuth 9 Christian Lengauer 11 K. Mani Chandy 13 Eric C.R. Hehner 15 Mark Scheevel 17 Krzysztof R. Apt 18 arXiv:2104.03392v1 [cs.GL] 7 Apr 2021 Niklaus Wirth 20 Lex Bijlsma 23 Manfred Broy 24 David Gries 26 Ted Herman 28 Alain J. Martin 29 J Strother Moore 31 Vladimir Lifschitz 33 Wim H. Hesselink 34 1 Hamilton Richards 36 Ken Calvert 38 David Naumann 40 David Turner 42 J.R. Rao 44 Jayadev Misra 47 Rajeev Joshi 50 Maarten van Emden 52 Two Tuesday Afternoon Clubs 54 2 Preface Edsger Dijkstra was perhaps the best known, and certainly the most discussed, computer scientist of the seventies and eighties. We both knew Dijkstra |though each of us in different ways| and we both were aware that his influence on computer science was not limited to his pioneering software projects and research articles. He interacted with his colleagues by way of numerous discussions, extensive letter correspondence, and hundreds of so-called EWD reports that he used to send to a select group of researchers.
    [Show full text]
  • Early Life: 1924–1945
    An interview with FRITZ BAUER Conducted by Ulf Hashagen on 21 and 26 July, 2004, at the Technische Universität München. Interview conducted by the Society for Industrial and Applied Mathematics, as part of grant # DE-FG02-01ER25547 awarded by the US Department of Energy. Transcript and original tapes donated to the Computer History Museum by the Society for Industrial and Applied Mathematics © Computer History Museum Mountain View, California ABSTRACT: Professor Friedrich L. Bauer describes his career in physics, computing, and numerical analysis. Professor Bauer was born in Thaldorf, Germany near Kelheim. After his schooling in Thaldorf and Pfarrkirchen, he received his baccalaureate at the Albertinium, a boarding school in Munich. He then faced the draft into the German Army, serving first in the German labor service. After training in France and a deployment to the Eastern Front in Kursk, he was sent to officer's school. His reserve unit was captured in the Ruhr Valley in 1945 during the American advance. He returned to Pfarrkirchen in September 1945 and in spring of 1946 enrolled in mathematics and physics at the Ludwig-Maximilians-Universitäat, München. He studied mathematics with Oscar Perron and Heinrich Tietze and physics with Arnold Sommerfeld and Paul August Mann. He was offered a full assistantship with Fritz Bopp and finished his Ph.D. in 1951 writing on group representations in particle physics. He then joined a group in Munich led by a professor of mathematics Robert Sauer and the electrical engineer Hans Piloty, working with a colleague Klaus Samelson on the design of the PERM, a computer based in part on the Whirlwind concept.
    [Show full text]
  • Oral History Interview with Friedrich L. Bauer
    An Interview with FRIEDRICH L. BAUER OH 128 Conducted by William Aspray on 17 February 1987 Munich, West Germany Charles Babbage Institute The Center for the History of Information Processing University of Minnesota, Minneapolis Copyright, Charles Babbage Institute 1 Friedrich L. Bauer Interview 17 February 1987 Abstract Bauer briefly reviews his early life and education in Bavaria through his years in the German army during World War II. He discusses his education in mathematics and theoretical physics at the University of Munich through the completion of his Ph.D. in 1952. He explains how he first came in contact with work on modern computers through a seminar in graduate school and how he and Klaus Samelson were led to join the PERM group in 1952. Work on the hardware design and on compilers is mentioned. Bauer then discusses the origins and design of the logic computer STANISLAUS, and his role in its development. The next section of the interview describes the European side of the development of ALGOL, including his work and that of Rutishauser, Samelson, and Bottenbrach. The interview concludes with a brief discussion of Bauer's work in numerical analysis in the 1950s and 1960s and his subsequent investigations of programming methodology. 2 FRIEDRICH L. BAUER INTERVIEW DATE: 17 February 1987 INTERVIEWER: William Aspray LOCATION: Deutsches Museum, Munich, West Germany ASPRAY: This is an interview on the 17th of February, 1987 at the Deutsches Museum in Munich. The interviewer is William Aspray of the Charles Babbage Institute. The interview subject is Dr. F. L. Bauer. Let's begin by having you discuss very briefly your early career in education, say up until World War II.
    [Show full text]
  • A Static Analysis Framework for Security Properties in Mobile and Cryptographic Systems
    A Static Analysis Framework for Security Properties in Mobile and Cryptographic Systems Benyamin Y. Y. Aziz, M.Sc. School of Computing, Dublin City University A thesis presented in fulfillment of the requirements for the degree of Doctor of Philosophy Supervisor: Dr Geoff Hamilton September 2003 “Start by doing what’s necessary; then do what’s possible; and suddenly you are doing the impossible” St. Francis of Assisi To Yowell, Olivia and Clotilde Declaration I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of the degree of Doctor of Philosophy (Ph.D.) is entirely my own work and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. Signed: I.D. No.: Date: Acknowledgements I would like to thank all those people who were true sources of inspiration, knowledge, guidance and help to myself throughout the period of my doctoral research. In particular, I would like to thank my supervisor, Dr. Geoff Hamilton, without whom this work would not have seen the light. I would also like to thank Dr. David Gray, with whom I had many informative conversations, and my colleagues, Thomas Hack and Fr´ed´ericOehl, for their advice and guidance. Finally, I would like to mention that the work of this thesis was partially funded by project IMPROVE (Enterprise Ireland Strategic Grant ST/2000/94). Benyamin Aziz Abstract We introduce a static analysis framework for detecting instances of security breaches in infinite mobile and cryptographic systems specified using the languages of the π-calculus and its cryptographic extension, the spi calculus.
    [Show full text]
  • Dines Bjørner Research, Bibliography, Biography and Publication List
    CV: Dines Bjørner Research, Bibliography, Biography and Publication List Professor of Computing Science (Emeritus). Fredsvej 11, DK-2840 Holte, Denmark Dr.h.c., MAE, MRANS (AB), ACM Fellow, IEEE Fellow May 16, 2010 Dines Bjørner, Sept. 2007 For more photos see Sect. 5 Contents 2.3 Book Covers ............... 5 1 My Research 2 3 Biography 7 2 Publication Notes 3 4 References 9 2.1 Year-by-Year Listing ........... 3 2.2 Statistics ................. 4 5 Photos 24 1 My Research My research, since my IBM Vienna days, has focused on computing science,1 in particular program- ming methodology: on how to construct software. I was never much for the more foundational 1By computing science I understand the study of and knowledge about how to construct the “things” that can exist “inside” computers: data and processes. 1 side of computing, or as I call it, computer science.2 3 I am in particular “smitten” by the question what is a method ?. I see a method as a set of principles to be used in the analysis of problems and in the synthesis of solutions to these problems. I see the analysis and synthesis to be based on techniques and tools. The principles are then about the selection and practical use of the analysis and synthesis techniques and tools — research must uncover these principles, techniques and tools. Software engineering textbooks must cover them.4 I see a good software development method to be one that provides for efficient development approaches resulting in efficient software that meets customers expectations (and only and exactly those) and software that is correct (that is satisfies its requirements).
    [Show full text]
  • A Programmer's Story. the Life of a Computer Pioneer
    A PROGRAMMER’S STORY The Life of a Computer Pioneer PER BRINCH HANSEN FOR CHARLES HAYDEN Copyright c 2004 by Per Brinch Hansen. All rights reserved. Per Brinch Hansen 5070 Pine Valley Drive, Fayetteville, NY 13066, USA CONTENTS Acknowledgments v 1 Learning to Read and Write 1938–57 1 Nobody ever writes two books – My parents – Hitler occupies Denmark – Talking in kindergarten – A visionary teacher – The class newspaper – “The topic” – An elite high school – Variety of teachers – Chemical experiments – Playing tennis with a champion – Listening to jazz – “Ulysses” and other novels. 2 Choosing a Career 1957–63 17 Advice from a professor – Technical University of Denmark – rsted’s inuence – Distant professors – Easter brew – Fired for being late – International exchange student – Masers and lasers – Radio talk — Graduation trip to Yugoslavia – An attractive tourist guide – Master of Science – Professional goals. 3 Learning from the Masters 1963–66 35 Regnecentralen – Algol 60 – Peter Naur and Jrn Jensen – Dask and Gier Algol – The mysterious Cobol 61 report – I join the compiler group – Playing roulette at Marienlyst resort – Jump- starting Siemens Cobol at Mogenstrup Inn – Negotiating salary – Compiler testing in Munich – Naur and Dijkstra smile in Stock- holm – The Cobol compiler is nished – Milena and I are married in Slovenia. 4 Young Man in a Hurr 1966–70 59 Naur’s vision of datalogy – Architect of the RC 4000 computer – Programming a real-time system – Working with Henning Isaks- son, Peter Kraft, and Charles Simonyi – Edsger Dijkstra’s inu- ence – Head of software development – Risking my future at Hotel Marina – The RC 4000 multiprogramming system – I meet Edsger Dijkstra, Niklaus Wirth, and Tony Hoare – The genius of Niels Ivar Bech.
    [Show full text]
  • UTP Semantics for Shared-State, Concurrent, Context-Sensitive Process Models
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Limerick Institutional Repository UTP Semantics for Shared-State, Concurrent, Context-Sensitive Process Models Andrew Butterfield Anila Mjeda John Noll Lero @ TCD Lero @ TCD Lero @ UL School of Computer Science and Statistics School of Computer Science and Statistics Tierney Building Trinity College, Dublin 2, Ireland Trinity College, Dublin 2, Ireland University of Limerick Email: Andrew.Butterfi[email protected] Email: [email protected] Email: [email protected] Abstract—Process Modelling Language (PML) is a notation semantics for shared global state concurrency, as a way to for describing software development and business processes. It get a suitable semantics for strict and flexible PML, inspired takes the form of a shared-state concurrent imperative language by the work of Woodcock and Hughes on unifying parallel describing tasks as activities that require resources to start and provide resources when they complete. Its syntax covers programming (UTPP, [13]). We present both a formal seman- sequential composition, parallelism, iteration and choice, but tics for a “weak” interpretation of PML, as well as a unified without explicit iteration and choice conditions. It is intended theory of concurrent programs (UTCP) that will provide a to support a range of context-sensitive interpretations, from a baseline theory for modelling more “flexible” and “strong” rough guide for intended behaviour, to being very prescriptive interpretations of PML. Part of our contribution is extending about the order in which tasks must occur. We are using Unifying Theories of Programming (UTP) to model this range of semantic the UTP methodology to use non-homogenous relations that interpretations, with formal links between them, typically of the mix dynamic state-change (observations with before- and nature of a refinement.
    [Show full text]
  • Short Biography
    Lecture Automation Mailüfterl Homeostat Calendar Science M Logic Algebra Informatics Wien Austria Academy of Sciences Computer Art B I Cybernetics January 1 1920 InformationOCG Theorie Digitalization IFA IP Logic Vienna Definition Language Radarforschung ALGOL ComputerM usic Formale Definition l K History IBM Labor Vienna Pulse-code modulation horezmi Vocoder Robotics Telecommunications URR IBM Fellow Semiotics Transmission Abstracte Architekture Language Theory Turtle HEINZ ZEMANEK Computer Language Vienna University of Technology Human Computer Interaction An Austrian Computer Pioneer Heinz Zemanek - Biographical data Heinz Zemanek was born in Vienna on 1 January 1920. Education and military service (1925 - 1947) 1925 - 1929 primary school Vienna 1929 - 1937 secondary school Vienna (graduation with honours in 1937) 1937 - 1944 studies of radio mechanics at the Technical University of Vienna (TU) 1940 - 1945 Military service in a communication unit of the Wehrmacht Employment: Teleprinter practice in Vienna Switchboard operator in Kronstadt and Sofia Work at the manual transmission centres in Thessaloniki, Athens und Belgrade Teacher at the Wehrmacht intelligence service school Thessaloniki High frequency research at the Ernst Lechner Institut in Reichenau/Semmering Technical academy of the Luftwaffe, institute for communication engineering in Berlin-Gatow Work at the Zentralversuchsstelle der Hochfrequenzforschung in Ulm-Dornstadt (high frequency research) University thesis: 1944, Über die Erzeugung von kurzen Impulsen aus einer Sinusschwingung
    [Show full text]
  • Druckversion Der Ausgabe Nr. 32 (Oktober 2014)
    Druckversion der Ausgabe Nr. 32 (Oktober 2014) TU|frei.haus – Druckversion der Ausgabe Nr. 32 (Oktober 2014) Inhaltsverzeichnis Inhaltsverzeichnis ........................................................................... 2 Editorial ........................................................................................ 4 Campus ........................................................................................ 5 TU Univercity 2015: Allerlei Neues vom Getreidemarkt bis zur Gusshausstraße ............................... 5 Quality Audit an der TU Wien: Die Schweizer Qualitätssicherungsagentur OAQ im Kurzporträt ..... 11 MitarbeiterInnenbefragung 2014: Wir – für uns alle! ......................................................................... 12 Paul Ludwik – ein Name für den Hörsaal 11 ..................................................................................... 13 AutorInnenverträge: Sichern Sie sich Ihre Rechte! ........................................................................... 14 OPEN ACCESS – Die neue Ära des Publizierens ............................................................................ 15 Einführungen in die Benutzung der Hauptbibliothek ......................................................................... 16 Smart Energy – Hinter den Kulissen des größten Plus-Energie-Bürohochhauses Österreichs ....... 17 8th European Conference on Gender Equality in Higher Education: Erfolge & offene Kernfragen .. 18 "Der Ö1 Hörsaal": Open Innovation an österreichischen Universitäten ...........................................
    [Show full text]
  • Domain Theory for Concurrency
    Domain Theory for Concurrency Mikkel Nygaard Glynn Winskel BRICS∗ Computer Laboratory University of Aarhus University of Cambridge Abstract A simple domain theory for concurrency is presented. Based on a categorical model of linear logic and associated comonads, it highlights the role of linear- ity in concurrent computation. Two choices of comonad yield two expressive metalanguages for higher-order processes, both arising from canonical construc- tions in the model. Their denotational semantics are fully abstract with respect to contextual equivalence. One language derives from an exponential of linear logic; it supports a straightforward operational semantics with simple proofs of soundness and adequacy. The other choice of comonad yields a model of affine-linear logic, and a process language with a tensor operation to be under- stood as a parallel composition of independent processes. The domain theory can be generalised to presheaf models, providing a more refined treatment of nondeterministic branching. The article concludes with a discussion of a broader programme of research, towards a fully fledged domain theory for concurrency. 1 Introduction Denotational semantics and domain theory of Scott and Strachey provide a global mathematical setting for sequential computation, and thereby place programming languages in connection with each other; connect with the mathematical worlds of algebra, topology and logic; and inspire programming languages, type disciplines and methods of reasoning. In concurrent/distributed/interactive computation that global mathematical gui- dance is missing, and domain theory has had little direct influence on theories of concurrent computation. One reason is that classical domain theory has not scaled up to the more intricate models used there.
    [Show full text]