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The focus of this paper is on how Active KDL can be used to provide a very powerful simulation support environment. Active KDL (Knowledge/Data Language) is an object-oriented database programming language, which provides access to integrated model, knowledge, and data bases. Simulation inputs and outputs can be stored by Active KDL since it supports complex objects. More importantly, Active KDL also allows users to specify rules to capture heuristic knowledge and methods to specify procedural behavior. Finally, Active KDL provides a simple mechanism for specifying concurrent execution, namely tasks embedded in active objects. These facilities provide a powerful mechanism for building simulation models out of pre-existing model components. These capabilities provide a tight coupling between a SIMODULA-like simulation system and a knowledge/database system, supporting query driven simulation, where model instantiation is used for information generation. 1. INTRODUCTION Query driven simu...

In the popular conception of hypertext as nonlinear writing, primary emphasis typically falls on the construction, character, and quantity of constituent lexias that comprise any given hypertext. This paper, however, will focus on what the text would reveal if an ordered collection were made of the links emerging from the main (first order) text. Such a collection, as a second order text or parallel text, which I propose to call the paratext, comprises the layerworld of links, of intertextual referents that could be subjected to cluster analyses that reveal aspects of cohesion, breadth, and other speculative characteristics of the first order text. KEYWORDS: Hypertext, intertextuality, link semantics, grammatology, paratext, rhetoric. INTRODUCTION This paper discusses the theme of augmenting possible understanding of a hypertext by applying an interpretive analysis of its links. The first part of the paper describes the concept and framework of the approach in critical terms. The se...

This paper discusses work which is a continuation of [Baker90]. Our birth control scheme for objects of LP type bears a strong resemblance to Barnes'es scheme for controlling access to a resource [Barnes89,9.3]. Barnes does not export a nesting generic unit to handle deallocation, however.

Introduction Most current hypertext systems use proprietary data formats for storage. Some researchers have tried using Relational Data Base Management Systems (RDBMS) to implement hypertext applications [Schutt & Streitz, 1990], [Meyrowitz, 1986]. There exists a large class of applications for which relational database management systems and other more conventionally structured database systems are too limited. These applications can be characterized as complex, large-scale, data-intensive programs such as CAD/CAM systems, documentation management systems, hypermedia systems, and geographical information systems. This class of applications needs a database model that is more expressive and flexible than the relational model. Some researchers believe that object-oriented databases can meet the data handling requirements of such applications. Among the many research issues in the area of hypermedia, database requirements of hypermedia systems have received very little attention.

The growing maturity of ODBMS technology is causing many enterprises to consider migrating relational databases to ODBMS’s. While data remapping is relatively straightforward in most cases, greater challenges lie in economically and non-invasively adapting legacy application software. We report on a genetics laboratory database migration experiment, which was facilitated by both organization of the relational data in object-like form and a C++ framework designed to insulate application code from relational artifacts. Although this experiment was largely successful, we discovered to our surprise that the framework failed to encapsulate three subtle aspects of the relational implementation, thereby “contaminating ” application code. We analyze the underlying issues, and offer cautionary guidance to future migrators. 1.