Wolfgang Klas – författare

This book presents the state-of-the-art in visual interfaces and database systems and covers the following topics in detail: next generation interfaces, visual representations, three-dimensional interfaces, modeling of visual information, image understanding and processing and video databases.

This study integrates computer-supported co-operative work (CSCW), workflow management systems (WFMS), and transaction processing (TP) technologies by first presenting a rigorous analysis of requirements presented by diverse classes of co-operative applications, ranging from co-operative authoring, through design for manufacturing, to interorganizational workflows. It then introduces a language that is suitable for the specification of co-operative activities. This language is based on a formal model and provides a collection of tools which allow the users to reason about the correctness of specifications, rather than relying on mechanisms that detect possible violations at run-time. The transaction model introduced in this monograph combines the use of private work spaces that allow individual participants to work independently, with synchronization mechanisms that allow them to combine their work to form a coherent whole. Finally, this monograph shows how the new transactional concepts developed in the project can be mapped into the transaction manager of an object-oriented database management system to provide a clean and efficient implementation.The book summarizes the state of the art of key technologies in co-operative activities and transactions. It should be useful to students, researchers, and technology developers in the areas of computer-supported co-operative work (CSCW), workflow management systems (WFMS), and transaction processing (TP) technologies, and is suitable as a text or reference for a graduate-level course on database systems or computer supported co-operative work.

Transaction Management Support for Cooperative Application is a comprehensive report on a successful international project, called TRANSCOOP, carried out from 1994 to 1997 by a group of European scientists. But the book is also much more than that, namely, an ambitious attempt to integrate Computer-Supported Cooperative Work (CSCW), Workflow Management Systems (WFMS), and Transaction Processing (TP) technologies. The very term {\em cooperative transactions} is in itself contradictory. Cooperation technologies, such as CSCW, aim at providing a framework for information exchange between cooperating (human) participants. In contrast, traditional transaction technologies allow concurrent users to operate on shared data, while providing them with the illusion of complete isolation from each other. To overcome this contradiction, the TRANSCOOP researchers had to come up with a new and original notion of correctness of concurrent executions, based on controlled exchange of information between concurrent users. Merging histories in accordance with prespecified commutativity rules among concurrent operations provides transactional guarantees to activities such as cooperative designing, which until now had to be carried out sequentially. As an interesting consequence, it also provides a basis for management of consistency between disconnected or mobile users who operate independently and yet, must occasionally reconcile their work with each other.

In many of nowadays web-based environments for electronic marketing and commerce, that present large multimedia product and service catalogues, it becomes more and more difficult to provide naive end users, such as private consumers or commercial business partners, with intuitive user interfaces to access the large multimedia collections describing the presented products and services. The same holds for marketing managers and other employees responsible for managing and maintaining the large and constantly changing set of multimedia information chunks and fragments contained in these collections. As a consequence, many efforts are devoted to improve the quality of the interaction between users and databases. Virtual Reality (VR) techniques are a promising interaction paradigm particularly suited to novice and/or occasional users. The users are facilitated in the database navigation since the system proposes them an environment that reproduces a real situation and gives the possibilityof interacting by manipulating objects that have a direct correspondence with known objects.