The Context Interchange strategy presents a novel approach for mediated data access in which semantic conflicts among heterogeneous systems are not identified a priori, but are detected and reconciled by a context mediator through comparison of contexts. This paper reports on the implementation of a Context Interchange Prototype which provides a concrete demonstration of the features and benefits of this integration strategy.

Expressions are presented for RPS reconnect delays in three basic cases: single path, multiple path with static reconnect, multiple path with dynamic reconnect. The assumption of homogeneous reconnects, which is introduced in the analysis, is shown to be implicit in many prior analyses. This assumption simplifies the resulting equations, but more general equations are also presented for the case where homogeneous reconnects are not assumed. These general results have not appeared previously. This paper also uses the assumption of constrained independence to derive a result for static reconnect which has only been derived previously using the maximum entropy principle. In the case of dynamic reconnect, constrained independence yields an entirely new closed form result. In addition to being a consistent extension of the static reconnect case, this new result is the only closed form expression for dynamic reconnect that yields a correct solution in certain saturated cases. Constrained independence can provide a useful alternative assumption in many other cases where complete independence is known to be only approximately correct.

Response Time Preservation (RTP) is introduced as a general technique for developing approximate analysis procedures for queueing networks. The underlying idea is to replace a subsystem by an equivalent server whose response time in isolation equals that of the entire subsystem in isolation. The RTP based approximations, which belong to the class of decomposition approximations, can be viewed as a dual of the Norton's Theorem approach for solving queueing networks since it matches response times rather than throughputs. The generality of the RTP technique is illustrated by developing solution procedures for several important queueing systems which violate product form assumptions. Examples include FCFS servers with general service times, FCFS servers with different service times for multiple classes, priority scheduling, and distributed systems.