CERN 94-06 14 October 1994 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 1993 CERN SCHOOL OF COMPUTING Scuola Superiore G. Reiss Romoli, L'Aquila, Italy 12-25 September 1993 PROCEEDINGS Eds. C.E. Vandoni, C. Verkerk GENEVA 1994 opyright eneve, 1 Propriété littéraire et scientifique réservée Literary and scientific copyrights reserved in pour tous les pays du monde. Ce document ne all countries of the world. This report, or peut être reproduit ou traduit en tout ou en any part of it, may not be reprinted or trans­ partie sans l'autorisation écrite du Directeur lated without written permission of the copy­ général du CERN, titulaire du droit d'auteur. right holder, the Director-General of CERN. Dans les cas appropriés, et s'il s'agit d'utiliser However, permission will be freely granted for le document à des fins non commerciales, cette appropriate non-commercial use. autorisation sera volontiers accordée. 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ISSN 0304-2898 ISBN 92-9083-065-4 CERN 94-06 14 October 1994 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 1993 CERN SCHOOL OF COMPUTING Scuola Superiore G. Reiss Romoli, L'Aquila, Italy 12-25 September 1993 PROCEEDINGS Eds. C.E. Vandoni, C. Verkerk GENEVA 1994 CERN-Service d'information scicntifique-RD/932-2000-octobre 1994 ABSTRACT These Proceedings contain the majority of the lectures given at the 1993 CERN School of Computing. Artificial neural networks were treated with particular emphasis on applications in particle physics. A discussion of triggering for experiments at the proposed LHC machine provided a direct connection to data acquisition in this field, whereas another aspect of signal processing was seen in the description of a gravitational wave interferometer. Some of the more general aspects of data handling covered included parallel processing, the IEEE mass storage system, and the use of object stores of events. Lectures on broadband telecommunications networks and asynchronous transfer mode described some recent developments in communications. The analysis and visualization of the data were discussed in the talks on general- purpose portable software tools (PAW++, KUIP and PIAF) and on the uses of computer animation and virtual reality to this end. Lectures on open software discussed operating systems and distributed computing, and the evolution of products like Unix, NT and DCE. m IV PREFACE The 1993 CERN School of Computing was the sixteenth in the series. For technical reasons it took place for the second time in succession in the "Scuola Superiore Guglielmo Reiss Romoli" in L/Aquila, Italy. Forty-nine students from fourteen countries took part. The participants enjoyed again the excellent facilities offered by the "Scuola Superiore G. Reiss Romoli". We express our sincere thanks to its Director, Professor S. Rotella and his deputies Dr. G. Ciccareila and Dr. B. Santariga, for having made the facilities of their School available to us. We are very grateful to Messrs.Collabianchi and Dundee for their extensive technical assistance in setting up the 3-D video projection. Mrs. Ingiacomo and Messrs. De Meo and Aglioti also provided invaluable help. The lecture programme was again much appreciated by the participants. All lecturers are sincerely thanked for their efforts in preparing and delivering their lectures, for providing - in most cases - written accounts of their presentation, and for their availability to discuss with the students. Very special thanks are due to Mr. Michael Bauer, who, in addition to his lectures, made a very impressive three-dimensional video presentation on applications of virtual reality at the NASA Ames Research Center. He spent a large amount of time, together with Messrs. Collabianchi and Dundee, to perfect the set-up. Their efforts were greatly appreciated by the students, who asked for a "bis". Silvano de Gennaro led the practical exercises on "Techniques for making presentations". The equipment for the exercises was made available at very short notice by Mr. A. Santariga from Computime, Rome. We thank him warmly. We are very grateful to Silvano, not only for his tutorial and exercises, but also for the musical entertainment he offered in the evenings. An excursion to the nearby underground laboratory of the Gran Sasso was appreciated by the participants. Everybody has doubtlessly good souvenirs of the excellent room and restaurant facilities of the Reiss Romoli Centre. The manager, Mr. Bardelli, and all his staff are sincerely thanked for having taken such good care. We express our sincere gratitude to Mrs. Ingrid Barnett, for her secretarial assistance. During many years she executed her secretarial duties with great competence and dedication. We wish her success in her new job! Finally, we thank the students for their active participation and we wish them success in their professional life. C.E. Vandoni, C. Verkerk, Editors. v 1993 ADVISORY COMMITTEE R. BRUN CERN, Geneva, Switzerland B.C. CARPENTER CERN, Geneva, Switzerland S. CENTRO Université di Padova, Italy R.F. CHURCHHOUSE University of Wales, Cardiff, U.K., (Chairman) R.W. DOBINSON CERN, Geneva, Switzerland C. VERKERK CERN, Geneva, Switzerland (Scientific Secretary) D.O. WILLIAMS CERN, Geneva, Switzerland P. ZANELLA Services Informatiques, Geneva, Switzerland and Centro di Ricerca, Sviluppo e Studi Superiore in Sardegna, Cagliari, Italy I. BARNETT CERN, Geneva, Switzerland (School Secretary) EDITORS' NOTE The material presented by Mr. Michael Bauer in his lectures on "Computer animation for scientific visualization" and on "Virtual reality; case studies at NASA Ames" are reproduced here in three papers: two (co-)authored by Mr. Bauer and one by Dr. S. Bryson. To their great regret, the editors did not succeed in obtaining written contributions from a number of lecturers, in spite of repeated efforts. VI CONTENTS Abstract iii Preface v Advisory Committee and Editors' note vi Table of contents vii Lecturers viii Neural networks, S. R. Amendolia 1 Databases and parallel processing, N. Winterbottom 36 The IEEE mass storage reference model, J. Shiers 44 Working with object stores of events using ptool, R. Grossman 66 Level-1 triggers for LHC experiments , E.F. Eisenhandler 98 Visualization of scientific data for high energy physics, R. Brun et al 121 Computer animation for scientific visualization, M. E. Bauer and K. C.Hu 179 Virtual reality - A general overview, M. E. Bauer 207 Virtual reality in scientific visualization, S. Bryson 217 Open software: UNIX, DCE, and Competitors, T. W. Doeppner 228 Broadband telecommunications networks and ATM, G. Ciccarella and T. Tofoni 249 Searching for gravitational waves, B. F. Schutz 274 List of participants (students) 295 vu 1993 LECTURERS S.R. AMENDOLIA University of Sassari and INFN of Pisa, Italy G. BATE Institute for Information Technology, Santa Clara University, U.S.A. M.E. BAUER Sterling Software, Palo Alto, CA, U.S.A. T.BERNERS-LEE CERN, Geneva, Switzerland R. BRUN CERN, Geneva, Switzerland G. CICCARELLA Scuola Superiore G. Reiss Romoli, L'Aquila, Italy M.S. DE GENNARO CERN, Geneva, Switzerland T.W. DOEPPNER Brown University, Providence, U.S.A. CECK CERN, Geneva, Switzerland E.F. EISENHANDLER Queen Mary and Westfield College, University of London, U.K. M. ERNST DESY, Hamburg, Germany R. GROSSMAN Laboratory for Advanced Computing, University of Illinois at Chicago, U.S.A. AJ.G. HEY University of Southampton, U.K. C.H. LLEWELLYN SMITH CERN, Geneva, Switzerland J.F. MORRISON Los Alamos National Laboratory, U.S.A. B.F. SCHUTZ Department of Physics and Astronomy, University of Wales, U.K. J. SHIERS CERN, Geneva, Switzerland N.M. STEPHENS Department of Computing Mathematics, University of Wales, U.K. N. WINTERBOTTOM University of Southampton, Parallel Applications Centre, U.K. V11I Neural Networks S.R.Amendolia University of Sassari and INFN of Pisa, Italy Abstract An introductory treatment of the subject of Neural Networks will be given. Topics covered will mostly be relevant for the use of Neural Networks in High Energy Physics, especially for triggering, and examples will be given of this application. 1. Basics of Neural Networks 1.1 Introduction There exist many papers and books on the subject of Neural Networks in the literature, and this cannot be an attempt at making a better or more comprehensive treatment. We send to the relevant references [1,2,3,4,5] jhe difficulty in this work, compared to previous treatments, is that the title does not quote a specific application of the Neural Networks, but deals with the entire matter instead. Since however the lectures were given to an audience of Physicists and Computer Scientists mostly involved in High Energy Physics related jobs, we shall narrow the scope and concentrate on aspects which can be useful in this domain of Science. Examples too will come from this field. 1.2 Complexity of tasks and structure of the human brain It is customary to start treatments on Artificial Neural Networks (ANN) making a comparison with the complexity of the human brain. The name ANN itself is used as a reminder of the fact that we are dealing with an emulation of the brain.