As group applications have become more prevalent, efficient network utilization becomes a growing concern. Multicast transmission may use network bandwidth more efficiently than multiple point-to-point messages, however, creating optimal multicast trees is prohibitively expensive. For this reason, heuristic methods are generally employed. These heuristics are often based on a Steiner tree approach, which is known to produce multicast trees that achieve an efficient use of network resources. Many such algorithms, both centralized and distributed, have been proposed to generate ‘good’ multicast trees. Even these heuristics typically have significant execution times, however, so changes to the initial group of multicast participants during generation of the tree is likely. Furthermore, periodic rebuilding of multicast trees or sub-trees has been proposed to improve the efficiency of these trees as the group membership evolves. Changes in group membership are also possible during this rebuilding process. Existing algorithms, however, either do not support changes to the multicast group during building of the tree or they impose unrealistic restrictions, such as no overlapping modifications or regeneration of the tree after every change. These restrictions prevent the use of such algorithms in many situations, e.g.; networks with mobile hosts. To remedy this, we propose an efficient distributed algorithm that supports dynamic changes to the multicast group during tree building and allows concurrent join/leave operations. In this paper, we present the algorithm, a proof of correctness, and detailed simulation results.

We present a set of library routines that allow easily parallelized graphics rendering routines that require no communication between each parallel task, such as ray‐tracing, to be run efficiently in an environment of distributed workstations. The presentation of the paper focuses on the problems encountered in implementing a distributed system under Unix and proposes solutions to each problem. Specifically, we discuss the challenges involved in overcoming the limits of communicating with a large number of processes in Unix and in providing fault tolerance when using sockets. Technical aspects of the implementation and some additional problems that were encountered are discussed. Finally, we compare the rendering times for a complex image with a renderer using the library and show that the library routines are able to exploit much of the existing parallelism. The library is presented using a graphics application, though the concepts are generic enough to be of use in designing any distributed system under Unix.

Research Articles| March 25 2010 Zur Frage der Fluothane-Narkose für chirurgische Eingriffe am Auge Subject Area: Ophthalmology D. Langrehr; D. Langrehr Aus der Chirurgischen Universitätsklinik Gieβen (Direktor: Prof. Dr. K. Vossschulte) und der Universitäts-Augenklinik, Pleoptik, Orthoptik und Motilitätsstörungen des Auges, Gieβen (Direktor: Prof. Dr. C. Cuppers) Search for other works by this author on: This Site PubMed Google Scholar F. Adelstein; F. Adelstein Aus der Chirurgischen Universitätsklinik Gieβen (Direktor: Prof. Dr. K. Vossschulte) und der Universitäts-Augenklinik, Pleoptik, Orthoptik und Motilitätsstörungen des Auges, Gieβen (Direktor: Prof. Dr. C. Cuppers) Search for other works by this author on: This Site PubMed Google Scholar H. L';Allemand H. L';Allemand Aus der Chirurgischen Universitätsklinik Gieβen (Direktor: Prof. Dr. K. Vossschulte) und der Universitäts-Augenklinik, Pleoptik, Orthoptik und Motilitätsstörungen des Auges, Gieβen (Direktor: Prof. Dr. C. Cuppers) Search for other works by this author on: This Site PubMed Google Scholar Ophthalmologica (1967) 153 (3): 200–214. https://doi.org/10.1159/000305061 Article history Published Online: March 25 2010 Content Tools Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation D. Langrehr, F. Adelstein, H. L';Allemand; Zur Frage der Fluothane-Narkose für chirurgische Eingriffe am Auge. Ophthalmologica 1 March 1967; 153 (3): 200–214. https://doi.org/10.1159/000305061 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsOphthalmologica Search Advanced Search Article PDF first page preview Close Modal This content is only available via PDF. 1967Copyright / Drug Dosage / DisclaimerCopyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements. You do not currently have access to this content.