Towards a unified view of design data and knowledge representation

Adequate information modeling in non-standard application areas (e.g. engineering applications such as CAD/CAM, VLSI design or knowledgebased applications) requires the abstraction concepts of classification, aggregation, generalization, and association. The Molecule-Atom Data model (MAD) designed for the effective support of such an information model is justified and described with its essential properties and features. MAD offers dynamic object definition and object handling, based on direct and symmetric management of network structures and recursiveness. These generic mechanisms can be used to map the above mentioned abstraction concepts in a straight-forward manner. Thus, the mapping of a wide variety of semantic and object-oriented modeling constructs, including complex objects with shared subobjects, becomes feasible. All these concepts are illustrated by means of some vivid examples taken from the areas of CAD/CAM and knowledge-based applications

Ein Molekül-Atom-Datenmodell für Non-Standard-Anwendungen : Anwendungsanalyse, Datenmodellentwurf und Implementierungskonzepte

Ziel der vorliegenden Arbeit ist die Erarbeitung und Nutzbarmachung von Datenbankkonzepten für sog. Non-Standard-Anwendungen. Darunter versteht man im OB-Bereich Anwendungen aus den Gebieten CAD/CAM, VLSI-Entwurf, Software-Entwicklung, Büroautomatisierung, Expertensysteme etc. Die zentralen Fragestellungen, zu denen es Antworten zu finden gilt, sind: - Welche Anforderungen werden von den Non-Standard-Anwendungen an die Datenhaltung gestellt? - Wie sehen dazu passende Architekturen und Datenmodelle für NDBS (das sind DBS für Non-Standard-Anwendungen) aus? - Nach welchen Konzepten sind solche NDBS zu entwerten und zu implementieren? Dazu werden verschiedene OB-basierte Prototypen analysiert und vergleichend einander gegenübergestellt. Im einzelnen wurden basierend auf konventionellen Datenbanksystemen verschiedenen Typs (Netzwerk- und Relationenmodell) Anwendungssysteme aus unterschiedlichen ingenieurwissenschaftlichen Bereichen (3D-Modellierung, Verwaltung geographischer Daten und VLSI-Entwurfswerkzeug) sowie aus dem Expertensystembereich (Diagnosesystem) entwickelt; ihr Leistungsverhalten wurde unter einer praxisnahen Last aufgezeichnet und detailliert untersucht. Ausgehend von diesen Analyse- und Vergleichsergebnissen wird ein Anforderungskatalog erstellt, der konkrete Aussagen über die Datenstrukturen der Anwendungsobjekte und die zugehörigen Verarbeitungscharakteristika zusammenfaßt

Beanspruchungsgerechtes Konstruieren : Kopplung von CAD und FEM

Die Kopplung der Bereiche CAD und FEM ist ein wesentlicher Schritt hin zu dem übergeordneten Ziel des fertigungsgerechten und beanspruchungsgerechten Konstruierens. Neue Bauteile werden mit CAD-Systemen entworfen und deren mechanische Eigenschaften anschließend mittels FEM-Systemen analysiert. Da diese Systeme auf ähnlichen Bauteilgeometrien aufbauen, ist es naheliegend, die im CAD-System vorliegende Geometriebeschreibung für die FEM-Analyse zu übernehmen. Ein direkter Austausch der Geometriedaten scheitert jedoch, da sich die jeweiligen Geometriemodelle stark unterscheiden. Aus diesem Grunde findet herkömmlicherweise kein rechnergestützter Datenaustausch statt. In dieser Arbeit berichten wir über die Konzepte, die Realisierung sowie über erste praktische Einsatzerfahrungen und Systembewertung zu einem Geometrie-Transformator (entwickelt für die Systeme EUCLID und ANSYS), der eine (weitestgehend) automatische Umsetzung der Geometriedarstellungen durchführt und somit einen durchgängigen rechnerunterstützten Prozeß für die Konversion vom CAD- zum FEM-Modell ermöglicht.The coupling of the two areas of computeraided design (CAD) and finite-element analyses (FEM) marks an important step towards the overall goal of manufacturing and stress-optimized design. New parts are developed with the help of CAD systems and their mechanical and stress characteristics are analysed by means of FEM systems. Since both system types rely on similar geometry it is straightforward to use the CAD geometry also for FEM purposes. A direct exchange of the geometry data will fail because the two geometries are quite different. In this article we report on the concepts, the realization as well as on first practical experiences and system assessment to a so-called geometry-transformer (designed for the EUCLID system and the ANSYS system), which employs an automatic geometry transformation, thus realizing a computer-supported conversion from CAD to FEM geometry

Extending the relational algebra to capture complex objects

An important direction in database research for non-standard applications (e.g. engineering or design applications) deals with adequate support for complex objects. Without doubt, the provision of network structures and shared subobjects as well as support for dynamic object definition and appropriate manipulation facilities is urgently needed for natural and accurate modeling as well as for efficient processing of the applications' objects. These concepts are the major concern of the molecule-atom data model (MAD model) and its molecule algebra which is introduced in this paper. They make the model stand out compared to the relational model and even to models limited to hierarchical and statically defined complex objects. By means of the molecule algebra a precise and complete specification of one conceivable kind of complex object processing and its inherent semantics is provided. Furthermore, this algebra is used as a sound basis to express the semantics of the high level query language MOL (molecule query language) that is able to deal with complex objects in a descriptive manner

Prevent Low-Quality Analytics by Automatic Selection of the Best-Fitting Training Data

Data analysis pipelines consist of a sequence of various analysis tools. Most of these tools are based on supervised machine learning techniques and thus rely on labeled training data. Selecting appropriate training data has a crucial impact on analytics quality. Yet, most of the times, domain experts who construct analysis pipelines neglect the task of selecting appropriate training data. They rely on default training data sets, e.g., since they do not know which other training data sets exist and what they are used for. Yet, default training data sets may be very different from the domain-specific input data that is to be analyzed, leading to low-quality results. Moreover, these input data sets are usually unlabeled. Thus, information on analytics quality is not measurable with evaluation metrics. Our contribution comprises a method that (1) indicates the expected quality to the domain expert while constructing the analysis pipeline, without need for labels and (2) automatically selects the best-fitting training data. It is based on a measurement of the similarity between input and training data. In our evaluation, we consider the part-of-speech tagger tool and show that Latent Semantic Analysis (LSA) and Cosine Similarity are suited as indicators for the quality of analysis results and as basis for an automatic selection of the best-fitting training data

Integration of composite objects into relational query processing : the SQL/XNF approach

Complex database applications, such as design applications, multi-media and AI applications, and even enhanced business applications can benefit significantly from a database language that supports composite objects. The data used by such applications are often shared with more traditional applications, such as cost accounting, project management, etc. Hence, sharing of the data among traditional applications and complex object applications is important. Our approach, called SQL Extended Normal Form (short SQL/XNF) provides a general framework that supports novel processing models based on composite objects. Especially, it enhances relational technology by a composite object facility, which comprises not only extraction of composite objects from a shared database, but also adequate browsing and manipulation facilities provided by an appropriate application programming interface

DB-Schnittstellen für arbeitsplatzorientierte Ingenieuranwendungen

Die Schnittstellen gegenwärtig verfügbarer Datenbanksysteme erweisen sich als ungeeignet für den Bereich der lngenieuranwendungen. Dies gilt im besonderen, da bei Ingenieuranwendungen eine deutliche Arbeitsplatzorientierung vorherrscht und sie damit häufig auf einer speziellen Mehrrechnerarchitektur aufbauen. Ausgehend von einem Schichtenmodell für sog. Non-Standard-Datenbanksysteme (NDBS) schlagen wir daher eine spezielle Systemarchitektur mit einer entsprechend ausgelegten Datenmodell- und Anwendungsmodellschnittstelle für arbeitsplatzorientierte Ingenieuranwendungen vor

Object orientation within the PRIMA-NDBS

In the following we wish to highlight the design and implementation concepts of a non-standard database system (NDBS) called PRIMA and its provision for object orientation

Towards effective support of engineering information systems

Existing interfaces to nowadays database systems show to be increasingly unsuitable for the evolving wide spectrum of engineering applications (e.g. CAD/CAM, geographic information management, knowledge-based systems for planning and design, etc.). This is further intensified due to the workstation-oriented processing scheme prevailing in the engineering area. Starting with an architectural approach tailored to this distributed processing concept, we propose the PRIMA-NDBS and its most important interfaces, i.e. the data model and the application/user interface offering effective support of engineering information systems