This paper describes a language that is intended to support software engineers in the development of information systems throughout the software lifecycle. This language is not a programming language. Following the example of a number of other software engineering projects, our work is based on the premise that information system development is knowledge-intensive and that the primary responsibility of any language intended to support this task is to be able to formally represent the relevant knowledge.

Research issues related to requirements modeling are introduced and discussed through a review of the requirements modeling language RML, its peers and its successors from the time it was first proposed at the Sixth International Conference on Software Engineering (ICSE-6) to the present---ten ICSEs later. We note that the central theme of "Capturing More World Knowledge" in the original RML proposal is becoming increasingly important in Requirements Engineering. The paper highlights key ideas and research issues that have driven RML and its peers, evaluates them retrospectively in the context of experience and more recent developments, and points out significant remaining problems and directions for requirements modeling research. 1. Introduction "...Requirements definition is a careful assessment of the needs that a system is to fulfill. It must say why a system is needed, based on current and foreseen conditions, which may be internal operations or an external market. It must say wh...

We review basic premises underlying the application of conceptual modelling to the development of information systems and point out a fundamental problem arising from the broad range of concepts that need to be modelled. We then argue that conventional conceptual models are weak for such broad domains of discourse because they come with built-in collections of primitive notions in terms of which conceptual modelling is to be done. Telos is then introduced as a conceptual modelling language designed for capturing knowledge about information systems and it is argued that, unlike its peers, it offers facilities not only for modelling an application but also the notions used to model an application. The presentation of features of the language is eclectic and generally non-technical. Details about Telos can be found in [Mylopoulos90] and [Koubarakis89].

1 Relational integrity checking technology can be transfered to deductive object bases by utilizing a simple logical framework for objects. The principles of object identity, aggregation and classification allow a more efficient constraint control by finer granularity of updates, composite updates and semantic constraint simplification. In many cases, meta-level constraints and deductive rules can be handled efficiently by a stepwise compilation approach. An extended integrity subsystem with these features has been implemented in the deductive object base ConceptBase. 1 This work was supported in part by the Commission of the European Community under ESPRIT Basic Research Action 3012 (CompuLog). A version of this paper will also appear in the Proc. Second Int. Conf. on Deductive and Object-Oriented Databases, Munich, Dec. 1991 1. Introduction Comprehensive and efficient integrity maintenance has been quoted as one of the major problems in next-generation databases. Systems l...

.<F3.733e+05> Advanced applications in fields such as CAD, software engineering, real-time process control, corporate repositories and digital libraries require the construction, efficient access and management of large, shared knowledge bases. Such knowledge bases cannot be built using existing tools such as expert system shells, because these do not scale up, nor can they be built in terms of existing database technology, because such technology does not support the rich representational structure and inference mechanisms required for knowledge-based systems. This paper proposes a generic architecture for a knowledge base management system intended for such applications. The architecture assumes an object-oriented knowledge representation language with an assertional sublanguage used to express constraints and rules. It also provides for general-purpose deductive inference and special-purpose temporal reasoning. Results reported in the paper address several knowledge base management ...

Deductive object bases attempt to combine the advantages of deductive relational databases with those of object-oriented models. We review modeling and optimization issues encountered during the development of ConceptBase, a prototype deductive object base supporting the Telos data model. We also report on a number of application experiences in the field of meta data management.

. The paper presents a novel compilation scheme for temporal integrity constraints and deductive rules expressed in an interval-based first-order temporal logic. Compilation builds a dependence graph with simplified forms of the constraints and rules. This permits the compiletime simplification of the formulae that have to be verified at run-time, as well as the precomputation of potential implicit updates. We show how simplified forms can be obtained with respect to transactions made up of arbitrary sequences of basic updates. Additional optimization steps exploit the organization of simplified forms in dependence graphs. 1 Introduction The maintenance of semantic integrity is recognized as a cornerstone issue for the development of data bases and knowledge bases alike [11], [27], [18]. Integrity constraints express application dependent semantics that are not built into the data structures used to represent knowledge. Additionally, they constitute a means for controlling the quality...

2009-09-23 Abstract. ConceptBase is a multi-user deductive object manager intended for conceptual modeling, meta modeling, and coordination in design environments. The system implements O-Telos, a dialect of Telos integrating properties of deductive and object-oriented languages. It uniformly represents all information regardless of its abstraction level (data, class, meta class, meta meta class etc.) in a single data structure called P-facts. The powerful deductive query language is seamlessly integrated into the meta class hierarchy. Modeling is supported by meta classing, deduction and integry checking, active rule specification, functional definition of computation, a module concept, and a historical database allowing to query past states of the database. These principles are combined orthogonally, e.g. deductive rules can be contained to modules, formulated for meta classes, employed in active rules using functional definitions to compute properties, and be revised without overwriting the earlier definitions. The Java-based usage environment offers an extensible palette of graphical, tabular, and textual user interfaces. The communication between the user clients and the object base is organized in a client-server architecture using TCP/IP.

This paper presents an introduction for the ESPRIT community of the recently started ESPRIT 11 project, PLUS (P5254). The goal of the project is the production of a robust natural language dialogue system integrating linguistic and non-linguistic knowledge in a principled way, based on the pragmatics theories of Grice and Searle, and using results in knowledge-base management systems and logic programming for the maintenance of dynamic contextual knowledge bases. We present the background assumptions, an overview of the system conceptual design, of the empirical research that has already been undertaken on real corpora and of re-usable system components. 1