Gerald Weiss

Implementation mechanisms for packet switched voice conferencing

A distributed control mechanism for managing a packet-switched voice conference connection is presented. The principal concept introduced is the idea of viewing a conference connection as a logical ring of participants. Alternative methods for implementing voice conferencing on both broadcast and point-to-point networks are introduced, analyzed, and compared. Tradeoffs between the two methods with respect to station workload and maximum number of conference participants are discussed. Experimental implementations on both a carrier-sense multi-access with collision detection (CSMA/CD) Ethernet and a token-ring ProNet are described. The mechanisms presented can be used as part of a packet-switched voice communications protocol that includes conferencing capabilities. >

Multimedia conferencing on local area networks

Management and implementation procedures for data delivery in multiparty, multimedia conferences on local area networks are considered. Earlier results are extended, and the requirements and mechanisms for delivering multiple information types-voice, video, file, memo, screen, and keyboard data-are outlined. The mechanisms presented are appropriate for both intranetwork and (homogeneous and heterogeneous) internetwork conferences. They are also examined for their applicability to networks with and without multicast transmission capabilities. Conference management issues are discussed, and experiences in designing and experimentally implementing voice-only and multimedia conference data-delivery schema are reviewed.<<ETX>>

A comparative analysis of implementation mechanisms for packet voice conferencing

A quantitative comparative analysis of alternative implementation methods is presented with respect to network transmission capabilities, gateway design, and the presence or absence of silence detection algorithms. Performance measures presented include station, gateway, and network workloads. In presenting the results, the authors account for the effects of different network configurations and capabilities. In particular, they distinguish between multicast-capable and nonmulticast-capable networks. Results are given for conferences on a single network and across interconnected networks.<<ETX>>

Packet switched voice conferencing across interconnected networks

The authors extend the logical ring control mechanism of C. Zielger et al. to the case of a multiparty conference across interconnected networks. In addition, the alternate implementation is expanded to allow for multiple-network connectivity. A comparative network between the alternate implementation methods with respect to station workload, gateway workload, network workload, and maximum number of conference participants is presented and discussed.<<ETX>>

Mechanisms for integrated voice and data conferencing

A distributed control mechanism for managing a multi-party, packet switched voice conference connection has been previously presented [Weis88, Weis90, Zieg89]. The principal concept introduced was to view a conference connection as a logical ring of participants. Alternate methods for implementing voice conferencing on both multicast-capable and non-multicast-capable networks were discussed and analyzed. The mechanisms were shown applicable to both intranet and internet conferences. This paper extends those results to allow for multi-party, integrated voice and data conferences. The paper introduces the technique developed and then presents experimental benchmark performance measures with respect to station and gateway workloads.

Monetary values: double trouble or dollars and sense?

It is curious but there is widespread misuse of floating-point types to represent monetary amounts in introductory programming classes. This is evident from a survey of popular CS1 textbooks. It is instructive to examine how dollars and cents and other currency values are represented in actual practice and how we can utilize those techniques in computer science education, for both the sake of correctness and to illustrate important general principles. Furthermore, it is particularly interesting to review the history of CS education and determine how this situation came to pass. The interplay between technology, academic cultures and institutional development turns out to be quite significant.