Techniques for organizational memory information systems

The KnowMore project aims at providing active support to humans working on knowledge-intensive tasks. To this end the knowledge available in the modeled business processes or their incarnations in specific workflows shall be used to improve information handling. We present a representation formalism for knowledge-intensive tasks and the specification of its object-oriented realization. An operational semantics is sketched by specifying the basic functionality of the Knowledge Agent which works on the knowledge intensive task representation. The Knowledge Agent uses a meta-level description of all information sources available in the Organizational Memory. We discuss the main dimensions that such a description scheme must be designed along, namely information content, structure, and context. On top of relational database management systems, we basically realize deductive object- oriented modeling with a comfortable annotation facility. The concrete knowledge descriptions are obtained by configuring the generic formalism with ontologies which describe the required modeling dimensions. To support the access to documents, data, and formal knowledge in an Organizational Memory an integrated domain ontology and thesaurus is proposed which can be constructed semi-automatically by combining document-analysis and knowledge engineering methods. Thereby the costs for up-front knowledge engineering and the need to consult domain experts can be considerably reduced. We present an automatic thesaurus generation tool and show how it can be applied to build and enhance an integrated ontology /thesaurus. A first evaluation shows that the proposed method does indeed facilitate knowledge acquisition and maintenance of an organizational memory

Abstraction over non-local object information in aspect-oriented programming using path expression pointcuts

Aspect-oriented software development (AOSD) consists of a number of technologies that promise a better level of modularization of concerns that cannot be separated in individual modules by using conventional techniques. Aspect-oriented programming (AOP) is one of these technologies. It allows the modularization at the level of software application code. It provides programmers with means to quantify over specific points in the base application code, called join points, at which the crosscutting concern code must be triggered. The quantification is achieved by special selection constructs called pointcuts, while the triggered code that is responsible for adapting the selected join point is provided by special construct called advice. The selection and adaptation mechanisms in aspect-oriented programming depend heavily on the distinguishing properties of the join points. These properties can either be derived from the local execution context at the join point or they are considered to be non-local to the join point. Aspect-oriented systems provide a plenty of pointcut constructs that support accessing the local join point properties, while they rarely support the non-local properties. A large research effort has been achieved to extend current aspectoriented systems in order to solve the problem of non-locality. However, none of these proposals support the non-local object relationships. There are many situations where a good abstraction over nonlocal object information is needed, otherwise, the developers will be obliged to provide complex and error-prone workarounds inside advice body that conceptually do not reflect the semantics of join point selection and mix it with the semantics of join point daptation. Such recurrent situations occur when trying to modularize the object persistence concern. Object persistence, the process of storing and retrieving objects to and from the datastore, is a classical example of crosscutting concern. Orthogonal object persistence meets the obliviousness property of AOP: The base code should not be prepared upfront for persistence. This thesis addresses the shortcomings in current aspect-oriented persistence systems. It shows that the reason for such shortcomings is due to the lack of supporting non-local object information by the used aspect-oriented languages. To overcome this problem, this thesis proposes a new extension to the current pointcut languages called path expression pointcuts that operate on object graphs and make relevant object information available to the aspects. As an explicit and complete construct, a formal semantics and type system have provided. Moreover, an implementation of path expression pointcuts is discussed in the thesis along with its usage to show how the aforementioned problems are resolved

Fifth Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools Aarhus, Denmark, October 8-11, 2004

This booklet contains the proceedings of the Fifth Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, October 8-11, 2004. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop0

Anfragebearbeitung in einem Datenbank-Kernsystem für Geo-Anwendungen unter Verwendung einer generischen Komponente zur Anfrageoptimierung

In erweiterbaren Datenbanksystemen müssen zur Berücksichtigung einer neuen Anwendungsdomäne neben neuen Datensätzen und benutzerdefinierten Datentypen auch neue Indexstrukturen zur Beschleunigung der Anfragebearbeitung, anwendungsbezogene Algorithmen und Operationen zur Erzeugung von Anfrageergebnissen sowie neue Schlüsselwörter für die Anfragesprache ergänzt werden können. Diese Arbeit beschreibt die in einem objektorientierten Datenbank-Kernsystems eingesetzten Konzepte zur Anfragebearbeitung und betont seine Erweiterbarkeit. Außerdem wird eine neue erweiterbare generische Komponente zur Anfrageoptimierung vorgestellt, die erstmals eine einfache Beschreibung sowohl der algebraischen Transformationen als auch der Optimierungsstrategie durch textuelle Optimierungsregeln ermöglicht. Dadurch werden zum einen eine leichte Änderbarkeit der Optimierungsstrategie und zum anderen eine einfache Berücksichtigung von Erweiterungen des Systems im Rahmen des Optimierungsprozesses sichergestellt