We introduce a model of self-organizing systems inspired by biological and Physics metaphors. The motivation for the development of this model is twofold, it enables us to identify critical properties of a system and to understand the important metrics characterizing its qualitative and the quantitative behavior. It also enables us to develop a methodology to investigate these systems and to carry out comparative studies of alternative policies that govern system behavior. We illustrate the application of the model with a preliminary study of a system designed to encourage green computing and we present some preliminary simulation results of the model.
I. MOTIVATIONEngineering modern computer and communication systems is increasingly more challenging because the systems are more complex and more difficult to manage and to use. The complexity of computer and communication systems is caused by several interrelated factors summarized in Figure 1. New applications are developed to satisfy the more diverse needs of an increasingly larger population of users. New devices such as sensors find a wide range of applications, and, in turn, trigger the development of new applications and attract new users. At the same time, the individual components of a system are more complex, for example, 2-4 core processors are ubiquitous now and will be replaced by multi-core systems with tens to hundreds of cores in the next few years. Connectivity and mobility, required by virtually all users of the systems, increase the complexity of the applications and of the computer and communication infrastructure. At the same time, physical limitations, such as heat removal, bandwidth availability, the capacity to store energy, and other factors place additional constrains upon system design. Last, but not least, we have finite resources and the optimization of resource consumption increases system complexity. . Larger segment of population using the systems New and more complex components Optimization of resource consumption New and more complex applications Complexity of computing and communication systems Interconnectivity + mobility Physical constraints Fig. 1. Some of the factors contributing to the complexity of modern computer and communication systems.While we have an intuitive notion of the system complexity, a rigorous definition that allows us to quantify and measure the complexity of a system is not universally accepted. The thermodynamic, von Neumann, and Shannon entropy are related to the number of states of a system, thus they reflect to some extent the system complexity. Kolmogorov complexity [1], [2] of an object is a measure of computational resources needed to specify the object. Using a Markovian assumption and a Kologorov complexity model, we argued that scheduling and resource management are more complex on a computational grid than on a service grid due to the finer granularity of resource allocation [3].We propose to uses the complexity of a program that simulates the system as a measure of complexity of the system; this...