Simple models of network access, with applications to the design of joint rate and admission control

At the access to networks, in contrast to the core, distances and feedback delays, as well as link capacities are small, which has network engineering implications that are investigated in this paper. We consider a single point in the access network which multiplexes several bursty users. The users adapt their sending rates based on feedback from the access multiplexer. Important parameters are the user's peak transmission rate p, which is the access line speed, the user's guaranteed minimum rate r, and the bound ε on the fraction of lost data. Two feedback schemes are proposed. In both schemes the users are allowed to send at rate p if the system is relatively lightly loaded, at rate r during periods of congestion, and at a rate between r and p, in an intermediate region. For both feedback schemes we present an exact analysis, under the assumption that the users' job sizes and think times have exponential distributions. We use our techniques to design the schemes jointly with admission control, i.e., the selection of the number of admissible users, to maximize throughput for given p, r, and ε. Next we consider the case in which the number of users is large. Under a specific scaling, we derive explicit large deviations asymptotics for both models. We discuss the extension to general distributions of user data and think times

All feasible plans using temporal reasoning

An interval-based temporal reasoning algorithm is applied to planning problems. The generation of all feasible temporal plans and its importance are discussed

Multi-dimensional knowledge representation with a fuzzy extension

Abstract This paper presents some prefiminary results of our current attempts to develop a hybrid multi-dimensional knowledge representation scheme which can handle both the incompleteness and uncertainty. We have started from the quantitative temporal constraint information, and extended it with possibilistic quantifiers. We have also extended the former towards a multidimensional constraint-based formalism. Finally we have combined these two extensions under a multi-dimensional possibilistic scheme. The context of spatio-temporal reasoning is one of the motivations for developing such a hybrid scheme. However, the major motivation for our work is coming from the muti-dimensional data modeling research[SHJM96] within the database area