1 Introduction -- 1.1 Research in Interactive Television Systems -- 1.2 Applications -- 1.3 The Problem of an Information Glut -- 1.4 Need for Agent-based Systems -- 1.5 Overview -- 2 Towards Personal Television Systems -- 2.1 Software Agent Definition -- 2.2 Related Work -- 2.3 Practical Issues and Examples -- 2.4 Intelligent Agent Research Applied to Television -- 3 Requirements -- 3.1 Requirements to Multimedia Environments -- 3.2 Requirements to Program Provision -- 3.3 Requirements to User-Specific Functions -- 3.4 Conclusion -- 4 Agent Run-Time Environment -- 4.1 System Standards -- 4.2 Multimedia Standards -- 4.3 Dynamic Generation of Multimedia Applications -- 5 Architecture of the Intelligent Media Agent -- 5.1 Multilayered Agent Approach -- 5.2 Module Description -- 5.3 Discussion of Privacy and Security Aspects -- 6 Program Descriptors and User Profiles -- 6.1 Classification Units -- 6.2 Program Descriptors -- 6.3 User Profile -- 6.4 Attribute Types -- 7 Matching and Clustering -- 7.1 Matching Methods -- 7.2 Application to Attribute Types -- 7.3 Matching Example -- 7.4 Clustering -- 8 Profile Initialization and Update -- 8.1 User Profiles Initialization -- 8.2 User Profile Reference Table -- 8.3 User Profile Updates -- 8.4 User Groups -- 9 Decision Support System -- 9.1 Characteristic Properties -- 9.2 User Behavior Variables -- 9.3 Reaction to Zapping -- 10 Implementation and Testing -- 10.1 Implementation based on the MHEG Standard -- 10.2 Implementation of the Electronic Program Guide Application -- 10.3 Evaluation with Respect to Requirements -- 10.4 Summary -- 11 Conclusions -- 11.1 Classification -- 11.2 Suggested Extensions -- Appendix A: Genre Trees -- Appendix B: Personal EPG Application based on JAVA -- Appendix C: The Administration Tool -- Appendix D: Sample Hit List.