Showing papers by "Munindar P. Singh published in 1993"

Specifying and Enforcing Intertask Dependencies

Abstract: Extensions of the traditional atomic transaction model are needed to support the development of multi system applications or work ows that ac cess heterogeneous databases and legacy applica tion systems Most extended transaction model s use conditions involving events or dependencies between transactions Intertask dependencies can serve as a uniform framework for de ning extend ed transaction models In this paper we introduce event attributes needed to determine whether a dependency is enforceable and to properly sched ule events in extended transaction models Using these attributes and a formalizationof a dependen cy into the temporal logic CTL we can automat ically synthesize an automaton that captures the computations that satisfy the given dependency We show how a set of such automata can be com bined into a scheduler that produces global com putations satisfying all relevant dependencies We show how dependencies required to implement re laxed transactions such as Sagas can be enforced and discuss brie y the issues of concurrency con trol safety and recoverability

Integrating enterprise information models in Carnot

Abstract: The authors describe a method for integrating separately developed information models. The models may be the schemas of databases, frame systems of knowledge bases, domain models of business environments, or process models of business operations. The method achieves integration at a semantic level by using an existing global ontology to develop semantic mappings among resources and resolve inconsistencies. The method is incorporated in a graphical integration tool. The integrated models provide a coherent picture of an enterprise and enable its resources to be accessed and modified coherently. >

A logic of intentions and beliefs

Abstract: Intentions are an important concept in Artificial Intelligence and Cognitive Science. We present a formal theory of intentions and beliefs based on Discourse Representation Theory that captures many of their important logical properties. Unlike possible worlds approaches, this theory does not assume that agents are perfect reasoners, and gives a realistic view of their internal architecture; unlike most representational approaches, it has anobjective semantics, and does not rely on anad hoc labeling of the internal states of agents. We describe a minimal logic for intentions and beliefs that is sound and complete relative to our semantics. We discuss several additional axioms, and the constraints on the models that validate them.

Declarative representations of multiagent systems

Abstract: This paper explores the specification and semantics of multiagent problem-solving systems, focusing on the representations that agents have of each other. It provides a declarative representation for such systems. Several procedural solutions to a well-known test-bed problem are considered, and the requirements they impose on different agents are identified. A study of these requirements yields a representational scheme based on temporal logic for specifying the acting, perceiving, communicating, and reasoning abilities of computational agents. A formal semantics is provided for this scheme. The resulting representation is highly declarative, and useful for describing systems of agents solving problems reactively. >

Task scheduling using intertask dependencies in Carnot

Abstract: The Carnot Project at MCC is addressing the problem of logically unifying physically-distributed, enterprise-wide, heterogeneous information. Carnot will provide a user with the means to navigate information efficiently and transparently, to update that information consistently, and to write applications easily for large, heterogeneous, distributed information systems. A prototype has been implemented which provides services for (a) enterprise modeling and model integration to create an enterprise-wide view, (b) semantic expansion of queries on the view to queries on individual resources, and (c) inter-resource consistency management. This paper describes the Carnot approach to transaction processing in environments where heterogeneous, distributed, and autonomous systems are required to coordinate the update of the local information under their control. In this approach, subtransactions are represented as a set of tasks and a set of intertask dependencies that capture the semantics of a particular relaxed transaction model. A scheduler has been implemented which schedules the execution of these tasks in the Carnot environment so that all intertask dependencies are satisfied.