Research on ontology is becoming increasingly widespread in the computer science community, and its importance is being recognized in a multiplicity of research fields and application areas, including knowledge engineering, database design and integration, information retrieval and extraction. We shall use the generic term information systems, in its broadest sense, to collectively refer to these application perspectives. We argue in this paper that so-called ontologies present their own methodological and architectural peculiarities: on the methodological side, their main peculiarity is the adoption of a highly interdisciplinary approach, while on the architectural side the most interesting aspect is the centrality of the role they can play in an information system, leading to the perspective of ontology-driven information systems.

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The simple event-condition-action (ECA) rule paradigm of active databases has proved very useful in many AI and database applications. However, its applicability goes beyond data management. ECA rules can be used in network management and monitoring, electronic commerce, security and access management, and other application areas to express policies-- collections of general principles specifying the desired behavior of a system. In this paper we use a declarative policy description language PDL, in which policies are formulated as sets of ECA rules. The main contribution of the paper is a framework for detecting action conflicts and finding resolutions to these conflicts. Conflicts are captured as violations of action constraints. The semantics of rules, and conflict detection and resolution are defined axiomatically using logic programs. Given a policy and a set of action constraints the framework defines a monitor that filters the output of the policy to satisfy the constraints. We briefly describe the architecture of a PDL-based policy server being used to provide centralized administration of a soft switch in a communication network and show how it can be augmented to handle conflict resolution.

The Semantic Web is based on XML and RDF as its fundamental standards for exchanging and storing information on the World Wide Web. Event-condition-action (ECA) rules are a natural candidate for supporting reactive functionality on XML or RDF repositories. In this paper we describe a language for ECA rules on XML and a prototype implementation of this language. We also discuss some preliminary ideas regarding a language for ECA rules operating on a graph/triple representation of RDF, and we describe the architecture of a distributed deployment of such RDF ECA rules.

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XML is a now a dominant standard for storing and exchanging information. With its increasing use in areas such asdatawarehousing and e-commerce, there is a rapidly growing need for rule-based technology to support reactive functionality on XML repositories. Eventcondition-action (ECA) rules automatically perform actions in response to events and are a natural facility to support such functionality. In this paper, we study ECA rules in the context of XML data. We de ne a simple language for specifying ECA rules on XML repositories. The language is illustrated by means of some examples, and its syntax and semantics are then speci ed more formally. We theninvestigate methods for analysing and optimising these ECA rules, a task which has added complexity in this XML setting compared with conventional active databases.

An active database is a database in which some operations are automatically executed when specified events happen and particular conditions are met. Several systems supporting active rules in an object-oriented data model have been proposed. However, several issues related to the integration of triggers with object-oriented modeling concepts have not been satisfactorily addressed. In this paper, we discuss issues related to trigger inheritance and refinement in the context of the Chimera active object-oriented data model. In particular, we introduce a semantics for an active object language that takes into account trigger inheritance and supports trigger overriding. Moreover, we state conditions on trigger overriding ensuring that trigger semantics is preserved in subclasses.

An active database consists of a traditional database supplemented by a set of Event-Condition-Action (ECA) rules. One of the key questions for active database designers is that of termination of the ECA rules. The behaviour of the ECA rules may be obscure and their semantics is often not specified formally. Consequently, developing termination analysis algorithms and proving their correctness is a challenging task. In this paper we address this problem for functional active databases by adopting an abstract interpretation approach. By "functional active databases" we mean active databases whose transaction execution semantics have been expressed in a purely functional language. Although we demonstrate our tech...

A guide to requirements modeling is presented in this paper, in which use cases and the conceptual model are directly obtained from a business modeling based on UML activity diagrams. After determining the business processes of the organization, and describing their workflows by means of activity diagrams, use cases are elicited and structured starting from the activities of each process, while the concepts of the conceptual model are obtained from the data that flow between activities. Furthermore, business rules are identified and included in a glossary, as part of the data and activities specification. One notable aspect of our proposal is that use case and conceptual modeling are performed at the same time, thus making the identification and specification of suitable use cases easier. Both use case and conceptual modeling belong to the requirements analysis phase, which is part of a complete process model on whose definition we are currently working. This process is being experimented in a mediumsized organism of a Regional Public Administration. 1

ABSTRACT: In this paper, we present our vision on the component based Information Systems (IS) development and propose a definition of an IS component (ISC). For us, an ISC is a particular IS, integrating static, dynamic and integrity rules specifications. The concept of hyperclasses (HCl) is used to implement the static space of an ISC. A HCl is built on a subset of conceptual classes, forming a unit with a defined semantic. The HCls offer a powerful kind of independence between the methods and the schema. They facilitate ISC refinement and integration. All these concepts also introduce kind of modularity in the definition, management and evolution of an IS.