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Whenever humans refer to time, they do so with respect to a specific underlying calendar. So do most software applications. However, most theoretical models of time refer to time with respect to the integers (or reals). Thus, ...

Integrating knowledge from multiple sources is an important aspect of automated reasoning systems.In previous work, we presented a uniform declarative and operational framework, based on annotated logics, for amalgamating multiple knowledge bases and data structures (e.g. relational, object-oriented, spatial, and temporal structures) when these knowledge bases (possibly) contain inconsistencies, uncertainties, and non-monotonic modes of negation. We showed that annotated logics may be used, with some modifications, to mediate between different knowledge bases. The multiple knowledge bases are amalgamated by embedding the individual knowledge bases into a lattice. In this paper, we describe how, given a network of sites where the different databases reside, it is possible to define a distributed semantics for amalgamated knowledge bases. More importantly, we study how the mediator may be distributed across multiple sites so that when certain conditions are satisfied, network failures do not affect the end results of queries that a user may pose. We specify different ways of distributing the mediator to protect against different types of network link failures and develop alternative soundness and completeness results. (Also cross-referenced as UMIACS-TR-93-81)...

This paper proposes the use of repetitive broadcast as a way of augmenting the memory hierarchy of clients in an asymmetric communication environment. We describe a new technique called "Broadcast Disks" for structuring ...

This paper describes a framework for providing the ability to use multiple specialized data parallel libraries and/or languages within a single application. The ability to use multiple libraries is required in many ...

Since their advent, computer networks have used event-based mechanisms for managing resources. While technological advances have resulted in computer networking becoming ubiquitous, the performance of the networks suffers ...

Recently, Brass and Dix showed (\emph{Journal of Automated Reasoning} \textbf{20(1)}, 1998) that the wellfounded semantics WFS can be defined as a confluent calculus of transformation rules. This lead not only to a simple ...

Automatic parallelization of real FORTRAN programs does not live up to users expectations yet, and dependence analysis algorithms which either produce too many false dependences or are too slow contribute ...

(Also cross-referenced as UMIACS-TR-95-61)

Irregular computation problems underlie many important scientific applications. Although these problems are computationally expensive, and so would seem appropriate for parallel machines, their irregular and unpredictable ...

In this paper, we propose the concept of using query execution feedback for improving database buffer management. A query feedback model which adaptively quantifies the page fault characteristics of all query access ...