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 Metadata only Processing and transaction concepts for cooperation of engineering workstations and a database server(1988) 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 of 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. Emperical 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 KUNICAD : ein datenbankgestütztes geometrisches Modellierungssystem für Werkstücke(1987) Härder, Theo; Hübel, Christoph; Langenfeld, Stefan; Mitschang, BernhardEs wird ein datenbankgestütztes, volumenorientiertes Modellierungssystem für Werkstücke beschrieben, das als Kernalgorithmus für die geometrische Modellierung ein volumenorientiertes Verfahren einsetzt. Zur Unterstützung der graphischen Repräsentation der Werkstücke werden intern zusätzlich Strukturen nach dem Begrenzungsflächenmodell gehalten, die automatisch aus den CSG-Strukturen abgeleitet und nachgeführt werden. Das KUNICAD-System wird durch seine Gesamtarchitektur, seine Benutzerschnittstelle und sein zugrundeliegendes Anwendermodell skizziert. Die Modellierungskomponente wird durch ihre wesentlichsten Aufgaben - die Darstellung der Objekte und ihre Handhabung - beschrieben. Eine objektunterstützende Datenbankschnittstelle wurde nach dem Zusatzebenen-Architekturkonzept auf der Basis eines CODASYL-Datenbanksystems (UDS) entwickelt. Das implementierte System gestattet das Studium von praxistauglichen CAD-Schnittstellen und erlaubt eine detaillierte Analyse des durch die Datenbankverwaltung bedingten Mehraufwands bei CAD-Operationen.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.