Portrait Dr. Stefan Dieker
Praktische Informatik IV
FernUniversität Hagen
D-58084 Hagen

Phone: +49-2331-987-4284
  Fax: +49-2331-987-4278
Email: Stefan.Dieker@fernuni-hagen.de

Short Biography

4/1996 Diploma degree (Dipl.-Inform.) in Applied Computer Science from the University of Dortmund
5/1996 - 11/1996 Software engineer at Quantum GmbH, Dortmund
Since 11/1996 Research staff member (wissenschaftlicher Mitarbeiter) at Lehrgebiet Praktische Informatik IV, FernUniversität Hagen
6/2001 Doctorate (Dr. rer. nat.) from the FernUniversität Hagen


My teaching activities include the following tasks:


My research interests include the following topics:
Architectures of modular extensible systems
Examples are the commercially available Informix Universal Server, research prototypes like Predator, or our group's SECONDO project.
Interfaces for extension modules
An extensible database system typically consists of a pre-implemented system frame providing well-known database functionality like transaction management, concurrency control, and recovery. These are common features of all database systems, independent of their underlying data model. An extension module is a set of new data types and operators on that types, provided by a database implementor (DBI). It can be registered with the system frame via the implementation of a number of support functions which during query processing will be called by the frame to create, delete, load, and save objects of types defined by the DBI, perform operations on those types, estimate operator execution costs, etc.

Here my focus of research is on the following aspects of extension module implementation:

  • Tools for the implementation of extension modules
  • Design of an interface between extension modules and the system frame
  • Properties of interfaces between cooperating modules
Query optimization in modular extensible systems
While a lot of research effort has been put on the investigation of query optimization methods for relational DBMSs, optimizing queries whose operators as well as their argument data types are not predefined is still an open issue.


Last change 07/23/01, Stefan Dieker