Distribution System Infrastructure Research Articles

Intelligent Adaptive Information Agents

Adaptation in open, multi-agent information gathering systems is important for several reasons. These reasons include the inability to accurately predict future problem-solving workloads, future changes in existing information requests, future failures and additions of agents and data supply resources, and other future task environment characteristic changes that require system reorganization. We have developed a multi-agent distributed system infrastructure, RETSINA (REusable Task Structure-based Intelligent Network Agents) that handles adaptation in an open Internet environment. Adaptation occurs both at the individual agent level as well as at the overall agent organization level. The RETSINA system has three types of agents. Interface agents interact with the user receiving user specifications and delivering results. They acquire, model, and utilize user preferences to guide system coordination in support of the user‘s tasks. Task agents help users perform tasks by formulating problem solving plans and carrying out these plans through querying and exchanging information with other software agents. Information agents provide intelligent access to a heterogeneous collection of information sources. In this paper, we concentrate on the adaptive architecture of the information agents. We use as the domain of application WARREN, a multi-agent financial portfolio management system that we have implemented within the RETSINA framework.

A communication infrastructure for a fault tolerant distributed real-time system

Distributed real-time systems should be composeable out of a set of autonomous components such that important system properties can be derived from the properties of the components. This paper proposes a communication infrastructure for distributed real-time systems that supports this goal. After a discussion of some fundamental conflicts between desirable protocol objectives the characteristics of different real-time communication protocols are investigated and compared. Finally a new combination of intra-node and inter-node protocols is presented.

Group presentation of multimedia applications in IXION

The IXION multimedia, distributed system infrastructure is introduced, and its model of synchronous group work support is described. The model of group work is composed of a small number of simple abstractions within the IXION computational model. These are fully integrated into the infrastructure layers, and the degree of integration extends to full multimedia capability for distributed group work. The model allows existing single user applications to be used by groups of users, as well as providing assistance with the implementation of new, purpose built group applications.