Invited Contributions -- Computational Game Theory and AI -- Optimal Agent Section -- Selected Papers -- Towards First-Order Temporal Resolution -- Approximating Most Specific Concepts in Description Logics with Existential Restrictions -- Bayesian Learning and Evolutionary Parameter Optimization -- Papers on Foundations -- Abductive Partial Order Planning with Dependent Fluents -- Constraint-Based Optimization of Priority Schemes for Decoupled Path Planning Techniques -- Possible Worlds Semantics for Credulous and Contraction Inference -- The Point Algebra for Branching Time Revisited -- Exploiting Conditional Equivalences in Connection Calculi -- Propositional Satisfiability in Answer-Set Programming -- Prediction of Regular Search Tree Growth by Spectral Analysis -- Theory and Practice of Time-Space Trade-Offs in Memory Limited Search -- Hierarchical Diagnosis of Large Configurator Knowledge Bases -- Towards Distributed Configuration -- Belief Update in the pGOLOG Framework -- Finding Optimal Solutions to Atomix -- History-Based Diagnosis Templates in the Framework of the Situation Calculus -- A Defense Model for Games with Incomplete Information -- Towards Inferring Labelling Heuristics for CSP Application Domains -- Addressing the Qualification Problem in FLUX -- Extracting Situation Facts from Activation Value Histories in Behavior-Based Robots -- Learning Search Control Knowledge for Equational Theorem Proving -- Intelligent Structuring and Reducing of Association Rules with Formal Concept Analysis -- Comparing Two Models for Software Debugging -- Inferring Implicit State Knowledge and Plans with Sensing Actions -- Papers on Applications -- Multi-agent Systems as Intelligent Virtual Environments -- OilEd: A Reason-able Ontology Editor for the Semantic Web -- Experiments with an Agent-Oriented Reasoning System -- Learning to Execute Navigation Plans -- DiKe - A Model-Based Diagnosis Kernel and Its Application -- Industrial Papers -- Constraints Applied to Configurations -- From Theory to Practice: AI Planning for High Performance Elevator Control -- Semantic Networks in a Knowledge Management Portal -- Collaborative Supply Net Management.

This volume contains the contributions to the Joint German/Austrian Con- rence on Arti?cial Intelligence, KI 2001, which comprises the 24th German and the 9th Austrian Conference on Arti?cial Intelligence. They are divided into the following categories: – 2 contributions by invited speakers of the conference; – 29 accepted technical papers, of which 5 where submitted as application papers and 24 as papers on foundations of AI; – 4 contributions by participants of the industrial day, during which companies working in the ?eld presented their AI applications. After a long period of separate meetings, the German and Austrian Societies ¨ for Arti?cial Intelligence, KI and OGAI, decided to hold a joint conference in Vienna in 2001. The two societies had previously held one joint conference. This took place in Ottstein, a small town in Lower Austria, in 1986. At that time, the rise of expert system technology had also renewed interest in AI in general, with quite some expectations for future advances regarding the use of AI techniques in applications pervading many areas of our daily life. Since then ?fteen years have passed, and we may want to comment, at the beginning of a newcentury, on the progress that has been made in this direction.