This book contains a selection of tutorials on hot topics in information technology, which were presented at the IFIP World Computer Congress. WCC2004 took place at the Centre de Congres Pierre Baudis, in Toulouse, France, from 22 to 27 August 2004. The 11 chapters included in the book were chosen from tutorials proposals submitted to WCC2004. These papers report on several important and state-of-the-art topics on information technology such as: Quality of Service in Information Networks Risk-Driven Development of Security-Critical Systems Using UMLsec Developing Portable Software Formal Reasoning About Systems, Software and Hardware Using Functionals, Predicates and Relations The Problematic of Distributed Systems Supervision Software Rejuvenation — Modeling and Analysis Test and Design-for-Test of Mixed-Signal Integrated Circuits Web Services Applications of Multi-Agent Systems Discrete Event Simulation Human-Centered Automation We hereby would like to thank IFIP and more specifically WCC2004 Tutorials Committee and the authors for their contribution. We also would like to thank the congress organizers who have done a great job. Ricardo Reis Editor QUALITY OF SERVICE IN INFORMATION NETWORKS Augusto Casaca IST/INESC, R. Alves Redol, 1000-029, Lisboa, Portugal. Abstract: This article introduces the problems concerned with the provision of end— end quality of service in IP networks, which are the basis of information networks, describes the existing solutions for that provision and presents some of the current research items on the subject. Key words: Information networks, IP networks, Integrated Services, Differentiated Services, Multiprotocol Label Switching, UMTS.