Search

Von analogen und digitalen Zugängen zur Kunst

Computing Art Reader

The field of declarative AI programming is briefly characterized. Its recent developments in Germany are reflected by a workshop as part of the scientific congress KI-93 at the Berlin Humboldt University. Three tutorials introduce to the state of the art in deductive databases, the programming language Gödel, and the evolution of knowledge bases. Eleven contributed papers treat knowledge revision/program transformation, types, constraints, and type-constraint combinations.

Interaction in Massive Courses

This article proposes an approach to rely on the standard operators of relational algebra (including grouping and ag- gregation) for processing complex event without requiring window specifications. In this way the approach can pro- cess complex event queries of the kind encountered in appli- cations such as emergency management in metro networks. This article presents Temporal Stream Algebra (TSA) which combines the operators of relational algebra with an analy- sis of temporal relations at compile time. This analysis de- termines which relational algebra queries can be evaluated against data streams, i. e. the analysis is able to distinguish valid from invalid stream queries. Furthermore the analysis derives functions similar to the pass, propagation and keep invariants in Tucker's et al. \Exploiting Punctuation Seman- tics in Continuous Data Streams". These functions enable the incremental evaluation of TSA queries, the propagation of punctuations, and garbage collection. The evaluation of TSA queries combines bulk-wise and out-of-order processing which makes it tolerant to workload bursts as they typically occur in emergency management. The approach has been conceived for efficiently processing complex event queries on top of a relational database system. It has been deployed and tested on MonetDB.

Automatic reactions triggered by complex events have been deployed with great success in particular domains, among others, in algorithmic trading, the automatic reaction to realtime analysis of marked data. However, to date, reactions in complex event processing systems are often still limited to mere modifications of internal databases or are realized by means similar to remote procedure calls. In this paper, we argue that expressive complex actions with support for composite work ows and integration of so called external actions are desirable for a wide range of real-world applications among other emergency management. This article investigates the particularities of external actions needed in emergency management, which are initiated inside the event processing system but which are actually executed by external actuators, and discuss the implications of these particularities on composite actions. Based on these observations, we propose versatile complex actions with temporal dependencies and a seamless integration of complex events and external actions. This article also investigates how the proposed integrated approach towards complex events and complex actions can be evaluated based on simple reactive rules. Finally, it is shown how complex actions can be deployed for a complex event processing system devoted to emergency management.