Capturing design dynamics : the CONCORD approach

'Computer-Supported Cooperative Work' is a young research area considering applications with strong demands on database technology. Especially design applications need support for cooperation and some means for controlling their inherent dynamics. However, today's CAD systems mostly consisting of a collection of diverse design tools typically do not support these requirements. Therefore, an encompassing processing model is needed that covers the overall design process in general as well as CAD-tool application in particular. As a consequence, this model has to be rich enough to reflect the major characteristics of design processes, e.g., goal-orientation, hierarchical refinement, stepwise improvement as well as team-orientation and cooperation. The CONCORD model that will be described in this paper, reflects the distinct properties of design process dynamics by distinguishing three levels of abstraction. The highest level supports application-specific cooperation control and design process administration, the second considers goal-oriented tool invocation and work-flow management while the third level provides tool processing of design data. To achieve level-spanning control, we rely on transactional facilities provided at the various system layers

On structuring primitives and communication primitives for design environments

The evolution of CAD systems can be described in several stages which reflect an increasing effort for system Integration. It starts from a file-and-translator approach evolving to a data-integrated tool environment, and finally reaching the stage of a data-integrated design environment for CAD (sometimes also called CAD Framework). In the following we will detail some aspects of these stages

Performance Evaluation of the Remote Cooperation System in PRIMA Abstract

In order to achieve acceptable performance when executing queries in enhanced database systems, e.g. for engineering and knowledge-based applications, intra-query as well as interquery parallelism are required. Therefore, systems exploiting different kinds of parallelism need an environment offering suitable implementation capabilities. This paper describes different mechanisms for supporting parallel query execution in enhanced database systems. In order to provide efficient intra- as well as inter-query parallelism in our enhanced database management system, we introduce the basic communication system, called Remote Cooperation System. Thereafter, we present alternative implementations and finally present an analysis of their performance behavior. We implemented two different system architectures which will be compared in more detail. In order to get a better assessment of theses implementations, we compare our measurements to those obtained with conventional remote procedure call facilities offered by operating systems. The results demonstrate that the Remote Cooperation System is a suitable basic communication system in order to efficiently realize parallel query execution, especially in our enhanced database system called PRIMA