15 Fakultätsübergreifend / Sonstige Einrichtung
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/16
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Item Open Access Information structures and database support for solid modeling(1989) Härder, Theo; Hübel, Christoph; Mitschang, BernhardThe question we are going to investigate is how to map solid representations to DB structures and how to process this information efficiently. Starting from analytical representations based on analytical methods we discuss the use of constructive solid geometry and boundary representation models with various refinements. Furthermore, additional submodels (organizational, technological, physical) are considered in order to obtain an overall product model. This model representing all important aspects of a complex design object may serve to derive special object representations needed by existing engineering tools or by mathematical methods (e.g. finite elements). Today's DBMS are unable to meet the increasing requirements of engineering applications that would prefer to use a DBMS. To alter this situation, a new generation of DBMS architectures tailored to the demands of such enhanced applications have to be developed. As a consequence, the flexibility and expressiveness of data models as well as the handling of application objects must be greatly improved before interactive design work can be supported. We outline our data model concepts and architectural decisions to provide effective data management support. Our DBMS architecture consists of a neutral kernel part running on a server machine and an application layer tailored to solid modeling tasks which together with the application, i.e. the solid modeler is allocated to the workstation.Item Open Access Using PRIMA-DBMS as a testbed for parallel complex-object processing(1992) Hübel, Christoph; Mitschang, Bernhard; Gesmann, Michael; Grasnickel, Andreas; Käfer, Wolfgang; Schöning, Harald; Härder, TheoThe PRIMA-DBMS approach is explained by introducing PRIMA's architecture and query processing framework. The PRIMA-DBMS constitutes a testbed that is flexible enough to support evaluation and validation of quite a variation of different strategies for complex-object processing taking into account different parallelization levels and different hardware environments. Thus, PRIMA marks an important step towards our main research goal concerning measures for efficient complex-object processing: the measures that are in competition with each other are query optimization, query evaluation strategies, and massive storage, that all benefit from parallelism. The programming environment that supports the parallel DBMS processing is introduced with special emphasis on its ability for parametrization and configuration. A case study of the PRIMA testbed illustrates our first investigations and demonstrates a methodology for evaluation and tuning of PRIMA configurations.Item Open Access Abbildung von Frames auf neuere Datenmodelle(1987) Härder, Theo; Mattos, Nelson Mendonca; Mitschang, BernhardEs wird die Abbildung von Frames mit ihren Modellierungskonzepten und charakteristischen Operationen auf objektorientierte Datenmodelle untersucht, um Wissensrepräsentation in sogenannten Non-Standard-Datenbanksystemen - beispielsweise für Expertensystem-Anwendungen - unterstützen zu können. Nach einem Vergleich der Eigenschaften von Relationenmodell, NF 2-Modell und MAD-Modell für diese Aufgabe wird eine Bewertung der verschiedenen Ansätze vorgenommen, um ihre Tauglichkeit für die Frame-Modellierung deutlicher herauszukristallisieren.Item Open Access Use of inherent parallelism in database operations(1986) Härder, Theo; Hübel, Christoph; Mitschang, BernhardNon-standard applications of database systems (e.g. CAD) are characterized by complex objects and powerful user operations. Units of work decomposed from a single user operation are said to allow for inherent semantic parallelism when they do not conflict with each other at the level of decomposition. Hence, they can be scheduled concurrently. In order to support this processing scheme it is necessary to organize parallel execution by adequate control units. Therefore, client-server processes and nested transactions are applied to hierarchically structure the DBS-operations. On the other hand, the DBS-code itself has to be mapped onto a multiprocessor system to take advantage of multiple processing units.Item Open Access PRIMA - a database system supporting dynamically defined composite objects(1992) Gesmann, Michael; Grasnickel, Andreas; Härder, Theo; Hübel, Christoph; Käfer, Wolfgang; Mitschang, Bernhard; Schöning, HaraldPRIMA is a non-standard database system developed at the University Kaiserslautern. Its major purpose is the support of engineering design applications, such as VLSI design and software engineering. The applications require tailored application-dependent interfaces which, however, all share basic notions like that of a composite object. Hence, the approach of PRIMA is to offer an application-independent complex-object interface (the moleculeatom data model, shortly called MAD model) and to provide means to easily augment this interface by application-dependent functionality. In the following, we will concentrate on the MAD model and its implementation.Item Open Access Knowledge base management systems - the bases of advanced CAD(1989) Deßloch, Stefan; Härder, Theo; Mattos, Nelson Mendonca; Mitschang, BernhardSemantic expressive representation of design objects, active system behavior combined with reasoning facilities, and efficient implementation concepts are necessary requirements for the construction of better CAD systems. Here, we describe our approach to a knowledge base management system and exemplify its usage for advanced CAD systems.Item Open Access PRIMA : a DBMS prototype supporting engineering applications(1987) Härder, Theo; Meyer-Wegener, Klaus; Mitschang, Bernhard; Sikeler, AndreaThe design of the Molecule-Atom Data model, aimed at the effective support of engineering applications, is justified and described with its essential properties and features. MAD offers direct and symmetric management of network structures and recursiveness, dynamic object definition and object handling allowing for both vertical and horizontal access. Its prototype implementation PRIMA is discussed using a multi-level model for the DBMS architecture. Our DBMS kernel provides a variety of access path structures, tuning mechanisms, and performance enhancements transparent at the data model interface. PRIMA is assumed to be used in different run-time environments including workstation coupling and multi-processor systems. In particular, it serves as a research vehicle to investigate the exploitation of "semantic parallelism" in single user operations.Item Open Access Coupling engineering workstations to a database server(1987) Härder, Theo; Hübel, Christoph; Meyer-Wegener, Klaus; Mitschang, BernhardA DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster 01 workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Empirical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail.Item Open Access Unterstützung der Ablaufsteuerung in Entwurfsumgebungen durch Versionierung und Konfigurierung(1994) Ritter, Norbert; Mitschang, Bernhard; Härder, Theo; Nink, UdoEine wesentliche Aufgabe von Entwurfsumgebungen besteht in der Integration von einzelnen, eigenständigen Entwurfswerkzeugen sowohl bzgl. einer gemeinsamen Datenhaltung als auch einer gemeinsamen Ablaufsteuerung. Dies erfordert zum einen die integrierte Verwaltung aller Entwurfsdaten sowie die Bereitstellung der für den werkzeugspezifischen Entwurf relevanten Daten. Versionierung und Konfigurierung stellen hierbei die zentralen Konzepte zur umfassenden Beschreibung der Entwurfsdaten dar. Daneben ist auch die Einbindung der einzelnen Werkzeuganwendungen in den Gesamtablauf zu bewerkstelligen. Hierzu wird eine geeignete Entwurfsablaufteuerung benötigt. Ihre Aufgaben bestehen vor allem in der Unterstützung einer kontrollierten Kooperation zwischen zusammenarbeitenden Entwerfern, in der Koordination ggf. vorgeplanter Folgen von Werkzeuganwendungen sowie in der Sicherung einer korrekten Interaktion der Werkzeuge mit der Entwurfsdatenverwaltung. In diesem Artikel beschreiben wir die zentralen Charakteristika der drei grundlegenden Konzepte: Versionierung, Konfigurierung und Ablaufsteuerung. Weiterhin diskutieren wir das Zusammenwirken dieser Konzepte im Rahmen einer Entwurfsumgebung. Dabei kommt deutlich zum Vorschein, daß die Datenbeschreibungsaspekte auf der einen Seite und die Ablaufaspekte auf der anderen Seite sowie deren Zusammenspiel die Eigenschaften einer konkreten Entwurfsumgebung, wie z.B. die Aspekte des parallelen Entwurfs oder die Fehlerbehandlung, entscheidend mitbestimmen.Item Open Access Capturing design dynamics : the CONCORD approach(1994) Ritter, Norbert; Mitschang, Bernhard; Härder, Theo; Gesmann, Michael; Schöning, Harald'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.