Analysis of large power systems

Computer-oriented power systems analysis procedures in the electric utilities are surveyed. The growth of electric power systems is discussed along with the solution of sparse network equations, power flow, and stability studies

Networking Foundations for Collaborative Computing at Internet Scope £

Despite significant proliferation of Internet services in recent years, technology for computer-supported cooperative work and groupware have not progressed at the same rate. A wider distribution of the work force motivates the need for networked multimedia and groupware at Internet scope and for larger groups of end-users. In particular, synchronous telecollaboration enables people in different geographic locations to bridge time and space by sharing and jointly manipulating multimedia information in realtime and at various levels of granularity. This aspect stands in contrast to legacy client-server applications such as Internet radio broadcast or video-on-demand, and to asynchronous, document-centric collaboration tools like email, instant messaging, or chat rooms. In this paper, we provide a framework for network-supported synchronous multimedia groupwork at Internet scope and for large user groups. Contributions entail an novel classification for such systems concerning scale and scope of interaction, a formal framework for Internet sessions and mediation of access to concurrently shared resources, a taxonomy of crucial elements in cooperative applications, and a discussion of a generic network coordination protocol to sustain live interaction among concurrently active user groups. The core ideas put forward in this paper are useful for the characterization and rapid prototyping of a new generation of collaborative applications. Keywords: Group coordination, Web-centric collaboration, Internet-wide Computer Supported Cooperative Work

Garcia-Luna-Aceves. Ordered end-to-end multicast for distributed multimedia systems

We address the problem of message ordering for reliable multicast communication. End-to-end multicast ordering is useful for ensuring the collective integrity and consistency of distributed operations. It is applicable for distributed multiparty collaboration or other multipoint applications, where the ordered reception of messages at all hosts is critical. Existing reliable multicast protocols largely lack support for ordering. Our novel mechanism can be added to existing reliable multicast services at low cost by performing cascaded total ordering of messages among on-tree hosts en route from senders to receivers. The protocol operates directly on a given end-to-end multicast tree, contrasting other tree-based approaches requiring a separate propagation graph to be built to compute ordering information. For better load distribution, resilience, and ordered subcasting of messages within multicast groups, sequencer nodes are elected dynamically based on address extensions to hosts in the multicast tree. A taxonomy of broadcast and multicast ordering solutions and comparative cost analysis show that reliable message delivery integrated with staggered ordering in endto-end multicast trees is more efficient, scalable, and less costly to deploy. Keywords: Tree-based ordered reliable multicast, group communication support for networked multimedia system