Christian Müller-Schloer

Organic computing: on the feasibility of controlled emergence

This paper gives an introduction to the new research area of Organic Computing and shows chances, opportunities and problems currently tackled by researchers. First the visions that lead to this new research area are discussed briefly. It is shown that the notion of emergence, a central phenomenon in Organic Compting, is a typical bottom-up effect with the interesting property of generating order from randomness. The classical design, however, is a top-down process. This apparent contradiction can be overcome by introducing so-called Observer/Controller architectures leading to the possibility to controlled emergence. The paper concludes with a description of current research problems in Organic Computing.

Adaptivity and self-organization in organic computing systems

Organic Computing (OC) and other research initiatives like Autonomic Computing or Proactive Computing have developed the vision of systems possessing life-like properties: they self-organize, adapt to their dynamically changing environments, and establish other so-called self-x properties, like self-healing, self-configuration, self-optimization, etc. What we are searching for in OC are methodologies and concepts for systems that allow to cope with increasingly complex networked application systems by introduction of self-x properties and at the same time guarantee a trustworthy and adaptive response to externally provided system objectives and control actions. Therefore, in OC, we talk about controlled self-organization. Although the terms self-organization and adaptivity have been discussed for years, we miss a clear definition of self-organization in most publications, which have a technically motivated background. In this article, we briefly summarize the state of the art and suggest a characterization of (controlled) self-organization and adaptivity that is motivated by the main objectives of the OC initiative. We present a system classification of robust, adaptable, and adaptive systems and define a degree of autonomy to be able to quantify how autonomously a system is working. The degree of autonomy distinguishes and measures external control that is exerted directly by the user (no autonomy) from internal control of a system which might be fully controlled by an observer/controller architecture that is part of the system (full autonomy). The quantitative degree of autonomy provides the basis for characterizing the notion of controlled self-organization. Furthermore, we discuss several alternatives for the design of organic systems.

Observation and Control of Organic Systems

Organic Computing (OC) assumes that current trends and recent developments in computing, like growing interconnectedness and increasing computational power, pose new challenges to designers and users. In order to tackle the upcoming demands, OC has the vision to make systems more life-like (organic) by endowing them with abilities such as self-organisation, self-configuration, self-repair, or adaptation. Distributing computational intelligence by introducing concepts like self-organisation relieves the designer from exactly specifying the low-level system behaviour in all possible situations. In addition, the user has the possibility to define a few high-level goals, rather than having to manipulate many low-level parameters.

Organic traffic light control for urban road networks

In recent years, autonomic and organic computing have become areas of active research in the informatics community. Both initiatives aim at handling the growing complexity in technical systems by focusing on adaptation and self-optimisation capabilities. A promising application for organic concepts is the control of road traffic signals in urban areas. This article presents an organic approach to traffic light control in urban areas that exhibits adaptation and learning capabilities, allowing traffic lights to autonomously react on changing traffic conditions. A coordination mechanism for neighbouring traffic lights is presented that relies solely on locally available traffic data and communication among neighbouring intersections, resulting in a distributed and self-organising traffic system for urban areas. The organic systems efficiency is demonstrated in a simulation-based evaluation.

Quantitative Emergence -- A Refined Approach Based on Divergence Measures

The article addresses the phenomenon of emergence from a technical viewpoint. A technical system exhibits emergence when it has certain kinds of properties or qualities that are irreducible in the sense that they are not traceable to the constituent parts of the system. In particular, we show how emergence in technical systems can be detected and measured gradually using techniques from the field of probability theory and information theory. To detect or measure emergence we observe the system and extract characteristic attributes from those observations. As an extension of earlier work in the field, we propose emergence measures that are well-suited for continuous attributes (or hybrid attribute sets) using either non-parametric or model-based probability density estimation techniques. We also replace the known entropy-based emergence measures by divergence measures for probability densities (e.g., the Kullback-Leibler divergence or the Hellinger distance). We discuss advantages and drawbacks of these measures by means of some simulation experiments using artificial data sets and a real-world data set from the field of intrusion detection.

Spatial Partitioning in Self-Organizing Smart Camera Systems

We propose a decentralized, self-organizing system architecture for wireless networked smart cameras (SCs) with pan, tilt, and zoom abilities. Each SC communicates with its neighbors and independently calculates the optimal position for its field of view. Thereby, SCs autonomously organize themselves and spatially partition the area they observe. This is achieved by a decentralized algorithm that makes way for self-organization in SC systems. The system quickly adapts to new situations caused by joining and failing nodes. Simulations with hundreds of cameras show that scalability and reliability are achieved. We analyze the performance of different camera densities and show that optimal surveillance coverage is achieved in a short time (20 s) while maintaining low communication traffic using a simulated 350-node outdoor SC system.

Emergence in organic computing systems: discussion of a controversial concept

Philosophy of mind has investigated the emergent behavior of complex systems for more than a century. However, terms such as “weak” or “strong” emergence are hardly applicable to intelligent technical systems. Organic Computing has the goal to utilize concepts such as emergence and self-organization to build complex technical systems. At first glance this seems to be a contradiction, but: These systems must be reliable and trustworthy! In order to measure, to control, and even to design emergence, a new notion or definition of emergence is needed. This article first describes the definition of emergence as used in philosophy of mind because this definition is often misunderstood or misinterpreted. Then, some very recent approaches for definitions of emergence in more or less technical contexts are discussed from the viewpoint of Organic Computing. The article concludes with some new thoughts that may help to come to a unifying notion of emergence in intelligent technical systems.

Towards Trust in Desktop Grid Systems

The Organic Computing (OC) Initiative deals with technical systems, that consist of a large number of distributed and highly interconnected subsystems. In such systems, it is impossible for a designer to foresee all possible system configurations and to plan an appropriate system behaviour completely at design time. The aim is to endow such technical systems with the so-called self-X properties, such as self-organisation, self-configuration or self-healing. In such dynamic systems, trust is an important prerequisite to enable the usage of Organic Computing systems and algorithms in market-ready products in the future. The OC-Trust project aims at introducing trust mechanisms to improve and assure the interoperability of subsystems. In this paper, we deal with aspects of organic systems regarding trustworthiness on the subsystem level (agents) in a desktop grid system. We develop an agent-based simulation of a desktop grid to show, that the introduction of trust concepts improves the systems performance, in such that they speed up the processes on the agent level. Specifically, we investigate a bottom-up self-organised development of trust structures that create coalition groups of agents that work more efficiently than standard algorithms. Here, an agent can determine individually to what extent it belongs to a Trusted Community.

An observer/controller architecture for adaptive reconfigurable stacks

In this paper, we discuss the necessity of new observation and control structures for organic computing systems starting from the basic contradiction between bottom-up behaviour and top-down design. An Observer/Controller architecture serves the purpose to keep emergent behaviour within predefined limits. As an illustration, a framework for reconfigurable protocol stacks is introduced, which contains an agent-based monitoring framework as well as a reconfiguration manager. After describing a TCP/IP protocol stack implementation, based on the framework, similarities between the introduced framework and the Observer/Controller architectural pattern will be pointed out.

Organic and Pervasive Computing – ARCS 2004

Autonomic computing systems have the ability to manage themselves and dynamically adapt to change in accordance with business policies and objectives. Self-managing environments can perform such activities based on situations they observe or sense in the IT environment, rather than requiring IT professionals to initiate the tasks. Autonomic computing is important today because the cost of technology continues to decrease yet overall IT costs do not. With the expense challenges that many companies face, IT managers are looking for ways to improve the return on investment of IT by reducing total cost of ownership, improving quality of service, accelerating time to value and managing IT complexity. The presentation will outline where IBM comes from with its autonomic computing initiative and what has been achieved to date. C. Müller-Schloer et al. (Eds.): ARCS 2004, LNCS 2981, p. 3, 2004. c