Contributions published at Department of Informatics (Burkhard Stiller)

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Virtual Reality (VR) systems are today being successfully employed for real-time visualization in such diverse fields as chemistry, medicine, simulation, construction, design, and architecture. Comparatively few, however, are being used for the interactive spatial display of large geographical datasets; such systems are neither generic nor portable, and are often only implementable on expensive high-end graphics workstations. Database-backed Geographical Information Systems (GISs) provide a multitude of possibilities for the manipulation of geographical data, without providing the real-time access to multi-dimensional data required by VR systems. The interactive visualization of large geographical data volumes does not rely, as do most GISs, on a two-dimensional presentation, but rather on three-dimensional visualization technology. Interactive display of spatial data requires an optimized computer graphics architecture. Common workplace computers have dramatically increased in power, offering today what would have been considered super-computer calculation power ten years ago. Optimized graphics subsystems are available for all common business Personal Computers (PCs), and offer a much better price-performance ratio than graphics super-workstations. Through hardware implementation of graphics routines, the display of three-dimensional datasets can be significantly accelerated. Computer Science has also made enormous progress. Through the use of object-oriented programming paradigms, problems can be specified on a very high, abstract level. This simplifies the implementation of portable, hardware-independent applications. Through the use of sophisticated object-oriented programming frameworks, ""Rapid Application Prototyping"" has become a key concept in modern software development. Complex applications can be easily assembled using special ""visual"" editors, with the underlying framework then filling in the necessary code. Highly sophisticated object-oriented frameworks, geared to the demands of VR visualization, provide the user with the possibility of creating virtual worlds with very little programming effort. This dissertation will show, through the implementation of physical models and advanced algorithms, that it is feasible to deploy an economically viable Virtual Reality system for the interactive visualization of large geographical datasets. The coupling of a VR system with an object-oriented database for the administration of large geographical data volumes offers both efficient memory and data retrieval management as well as interactive visualization. The implementation of two concrete applications and the concept of code reuse will show that the effort required for the development of VR systems is not significantly increased. The use of a VR framework allows the software engineer to provide a skeleton program possessing all the required components of a VR-based geographical information system. The terms Virtual Reality and Geographical Information Systems, and their integration into a Virtual Reality based Geographical Information System, are discussed in chapter 1. In chapter 2, the architecture of an existing VR system for visualizing large geographical datasets is taken as the foundation for further development with WordView. The foundations of software engineering for Virtual Reality applications are discussed in chapter 3. Chapter 4 is concerned with the necessary hardware requirements for such systems. Chapter 5 covers the use of standard software packages for implementing Virtual Reality systems. Aspects of system architecture, development, and implementation with the WorldView Virtual Reality framework are discussed in chapter 6. Chapter 7 covers applications based on WorldView used for antenna placement optimization and building visualization. Price/performance measurements are a central element of real-time applications and are covered in chapter 8 with reference to a WorldView prototype application. Final comments and ideas for future research activities are discussed in chapter 9.

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Recently, there have been various attempts to set up a test suite covering the syntactic phenomena of a natural language (cp. Flickinger et al. 1989, Nerbonne et al. 1993). The latest effort is the TSNLP project (Test Suite for Natural Language Processing) within the Linguistic Research and Engineering (LRE) framework sponsored by the European Union (cp. Balkan et al. 1994). These test suites are meant for the testing of NLP software regarding their coverage of syntactic phenomena. Volk 1995 showed that a well-organised test suite can also be used to support incremental grammar development and grammar documentation. The key issues in the organisation of a test suite are the ease of extensibility and interchangeability as well as the avoidance of redundancy. We have implemented a test suite, which is optimized for the avoidance of redundancy and we report on the trade-off for extensibility and interchangeability.

Translating idioms is one of the most difficult tasks for human translators and translation machines alike. The main problems consist in recognizing an idiom and in distinguishing idiomatic from non-idiomatic usage. Recognition is difficult since many idioms can be modified and others can be discontinuously spread over a clause. But with the help of systematic idiom collections and special rules the recognition of an idiom candidate is always possible. The distinction between idiomatic and non-idiomatic usage is more problematic. Sometimes this can be done by means of special words that are only used in an idiom. But in general this distinction is a question of semantics and pragmatics and therefore beyond the abilities of current translation systems. In this paper we investigate the requirements for automatically recognizing idioms and we check whether idiom recognition is possible within current translation systems, i.e. machine translation and translation memory systems. This is of current interest since the developers of translation systems have started to include huge idiom collections in their products.

Based on our experiences in the corporate banking department of the Union Bank of Switzerland we are convinced that business, IT and organizational aspects have to be considered in an integrated way while developing IT-strategies. IT-strategies are crucial for an effective (business) development because they identify the constant and the changing parts of an IT infrastructure during product life cycle. In order to achieve this, we state three design invariants: the deep structure of the process, the dependencies within the process, and the information handled. We believe that identifying these invariants will lead to a deeper understanding of product-life-cycles.

This article investigates how to support process enactment in highly flexible organizations. First it develops the requirements for such a support system. Then it proposes a prototype implementation, which offers its users the equivalent of a CAD/CAM-like tool for designing and supporting business processes. The tool enables end.users to take flexible building blocks of a production process, reassemble them to fit the specific needs of a particulr case and finally exports its description to process support systems like workflow management systems.

Der Artikel faßt die Erfahrungen bei der Einführung von Telekooperationstechnologie für Entscheidungsträger zusammen: Im Projekt Cuparla (Computerunterstützte Parlamentsarbeit), das Gemeinderäte inden Städten Stuttgart und Kornwestheim verband, spielte der Wettbewerb untereinander eine große Rolle bei der Nutzung der Technologie. - Wettbewerb mit den Kollegen ist gerade für Entscheidungsträger ein auch sozialer Anreiz zur persönlichen Nutzung von Telekooperationstechnologie. - Telekooperation kann für den Wettbewerb auf der Ebene des Individuums, der Gruppe, der Organisation und zwischen Organisationen Wirkung entfalten, d.h., es gibt meist mehrere Ansatzpunkte, um Wettbewerb als Anreiz für die Systemnutzung zu verwenden. - Eine Einführungsstrategie sollte daher so angelegt sein, daß Entscheidungsträger durch die Nutzung von Telekooperationstechnologie zumindest zeitweise ein Wettbewerbsvorteil erreichen oder ein Wettbewerbsnachteil vermeiden können. Geschickt eingesetzt, kann Wettbewerb untereinander auch Anfänger direkt zur Nutzung führen.

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