Organic Computing – Addressing Complexity by Controlled Self-organization J¨ urgen Branke 2 , Moez Mnif 1 , Christian M¨ uller-Schloer 1 , Holger Prothmann 2 , Urban Richter 2 , Fabian Rochner 1 , and Hartmut Schmeck 2 1 Universit¨at Hannover – Institute of Systems Engineering Appelstr. 4, 30167 Hannover, Germany {mnif|cms|rochner}@sra.uni-hannover.de 2 Universit¨at Karlsruhe (TH) – Institute AIFB 76128 Karlsruhe, Germany {jbr|hpr|uri|hsch}@aifb.uni-karlsruhe.de Abstract. In the past, the focus of the computer industry has been to improve hardware performance and add more and more features to the software. As a result, more and more appliances surrounding us are equipped with embedded computational power and wireless communica- tion. As such, they become ever more flexible and multifunctional, and almost indispensable in daily life. On the other hand, the resulting sys- tems become increasingly complex and unreliable, posing new challenges to designer and user. Organic Computing (OC) has the vision to address the challenges of complex distributed systems by making them more life-like (organic), i.e. endowing them with abilities such as self-organization, self-configuration, self-repair, or adaptation. The designer’s task is simplified, because it is no longer necessary to exactly specify the low-level system behavior in all possible situations that might occur, but instead leaving the system with a certain degree of freedom which allows it to react in an intelligent way to new situations. Also, use of such systems is simplified, as they can be controlled by setting few high-level goals, rather than having to manipulate many low-level parameters with unclear influence. In this paper, we give a general introduction to OC, and propose a generic observer-controller architecture as a framework for designing OC sys- tems. Then, it is shown how to use this architecture at the example of a traffic light controller. The paper concludes with a summary and a discussion of future challenges. Key words: Organic Computing, observer/controller, traffic control 1 Introduction The impressive progress in computing technology over the past decades has not only led to an exponential increase in available computing power, but at the same time shrunk the chips to a miniature format. While only 20 years ago, the pre- dominant computing platform was a company mainframe shared by many users,