On Using Multiagent Systems for Spectrum Sharing in Cognitive Radios Networks

In modern day wireless networks, spectrum utilization and allocation are static. Generally, static spectrum allocation is not a feasible solution considering the distributed nature of wireless devices, thus some alternatives must be ensured in order to allocate spectrum dynamically and to mitigate the current spectrum scarcity. An effective solution to this problem is cognitive radio (CR), which seeks the empty spectrum portions and shares them with the neighboring devices. The CR devices can utilize the available spectrum more efficiently if they try to work together. Therefore, in this work, we review a number of dynamic spectrum allocation techniques, especially those using multiagent systems and game-theoretical approaches, and investigate their applicability to CR networks. The distributed nature of these two domains makes them suitable for CR networks. In fact, the idea of dynamic spectrum sharing using these techniques is not entirely new and several interesting approaches already exist in literature. Thus, in our study we try to focus on existing spectrum sharing literature and cooperative multiagent system for CR networks. We are particularly interested in showing how the distributed nature of multiagent system can be combined with cognitive radios in order to alleviate the current static spectrum usage as well as maintaining cooperation amongst the CR nodes. Moreover, our work includes the description of various scenarios in which spectrum sharing is an essential factor and hence must be performed in a dynamic and opportunistic manner. We also explain the working of our proposed spectrum allocation approach using multiagent system cooperation in one of these scenarios and verify its formal behavior using Petri net modeling.

Formal Specification and Verification of Self-Configuring P2P Networking

In mobile environments (MEs) such as vehicular ad hoc networks (VANETs), mobile ad hoc networks (MANETs), wireless sensor networks (WSNs), and so on, formal specification of self-configuring P2P networking (SPN) emerges as a need for programming, and verifying such mobile networks. Moreover, well-specified SPN in MEs becomes a requirement of developing middleware for the mobile networks. The chapter is a reference material for readers who already have a basic understanding of the MEs for their applications and are now ready to know how to specify and verify formally aspect-oriented self-configuring P2P networking (ASPN) in MEs using categorical language, assured that their computing needs are handled correctly and efficiently. ASPN in MEs is presented in a straightforward fashion by discussing in detail the necessary components and briefly touching on the more advanced components. Several explanatory notes and examples are represented throughout the chapter as a moderation of the formal descriptions. Significant properties of ASPN in MEs, which emerge from the specification, create the firm criteria for verification.

Bio-Inspired Techniques for Topology Control of Mobile Nodes

In this chapter, we introduce a topology control mechanism based on genetic algorithms (GAs) within a mobile ad hoc network (MANET). We provide formal and practical aspects of convergence properties of our force-based genetic algorithm, called FGA. Within this framework, FGA is used as a decentralized topology control mechanism among active running software agents to achieve a uniform spread of autonomous mobile nodes over an unknown geographical terrain. FGA can be treated as a dynamical system in order to provide formalism to study its convergence trajectory in the space of possible populations. Discrete time dynamical system model is used for calculating the cumulative effects of our FGA operators such as selection, mutation, and crossover as a population of possible solutions evolves through generations. To demonstrate applicability of FGA to real-life problems and evaluate its effectiveness, we implemented a simulation software system and several different testbed platforms. The simulation and testbed experiment results indicate that, for important performance metrics such as normalized area coverage (NAC) and convergence rate, FGA can be an effective mechanism to deploy nodes under restrained communication conditions in MANETs operating in unknown areas. Since FGA adapts to the local environment rapidly and does not require global network knowledge, it can be used as a real-time topology controller for realistic military and civilian applications.

Logical Methods for Self-Configuration of Network Devices

The goal of self-configuration consists of providing appropriate values for parameters that modulate the behaviour of a device. In this chapter, self-configuration is studied from a mathematical logic point of view. In contrast with imperative means of generating configurations, characterized by scripts and templates, the use of declarative languages such as propositional or first-order logic is argued. In that setting, device configurations become models of particular logical formulæ, which can be generated using constraint solvers without any rigid scripting or user intervention.

Network-Aided Session Management for Adaptive Context-Aware Multiparty Communications

Recent years, from about the early 2000s, have been characterized by global broadband penetration, Fixed-Mobile-Convergence, Triple Play, and content provisioning over All-IP multimedia networks. Increasing demands in group-based multimedia sessions and market forces are fuelling the design of the future Internet, which is expected to fundamentally change the networking landscape in the upcoming years. Context, understood as sensed information that changes over time, has already led, to some extent, to service adaptation in terms of recognizing and using simple context, e.g. location. Context may also include network or personal state, location, or weather. To allow for session adaptation, it is important to use network and user context to enhance the existing service, keeping the user satisfied throughout the session.

Genetic Programming for System Identification

This chapter discusses the features of genetic programming based identification approaches, starting with the connected theoretical background. The presentation reveals both advantages and limitations of the methodology and offers several recommendations useful for making GP techniques a valuable alternative for mathematical models’ construction. For a sound illustration of the discussed design scheme, two GP-based multiobjective algorithms are suggested. They permit a flexible selection of nonlinear models, linear in parameters, by advantageously exploiting their particular structure, thus improving the exploration capabilities of GP and the interpretability of the resulted mathematical description. Both model accuracy and parsimony are addressed, by means of non-elitist and elitist Pareto techniques, aimed at adapting the priority of each involved objective. The algorithms’ performances are illustrated on two applications of different complexity levels, namely the identification of a simulated system, and the identification of an industrial plant.

Swarm Intelligence in Autonomic Computing

Autonomic computing has become increasingly popular during recent years. Many mobile autonomic and context-aware applications exhibit self-organization in dynamic environments adopted from multi-agent, or swarm, research. The basic paradigm behind swarm systems is that tasks can be more efficiently dispatched through the use of multiple, simple autonomous agents instead of a single, sophisticated one. Such systems are much more adaptive, scalable, and robust than those based on a single, highly capable, agent. A swarm system can generally be defined as a decentralized group (swarm) of autonomous agents (particles) that are simple, with limited processing capabilities. Particles must cooperate intelligently to achieve common tasks.

Theoretical and Practical Aspects of Developing Autonomic Systems with ASSL

ASSL (Autonomic System Specification Language) is an initiative for self-management of complex systems whereby the problem of formal specification, validation, and code generation of autonomic systems is approached within a framework. Being a formal method dedicated to autonomic computing, ASSL helps developers with problem formation, system design, system analysis and evaluation, and system implementation. The framework provides a powerful formal notation and suitable mature tool support that allow ASSL specifications to be edited and validated and Java code to be generated from any valid specification. As part of the framework’s proof-of-concept strategy, ASSL has been used to make a variety of existing and prospective systems autonomic. This entry presents the ASSL formal specification model and tools. Moreover, two case studies are presented to reveal practical aspects of using ASSL for the development of prototypes of prospective space exploration systems incorporating autonomic features.

Formal Methods for the Development and Verification of Autonomic IT Systems

This chapter explores ways in which rigorous mathematical techniques, termed formal methods, can be employed to improve the predictability and dependability of autonomic computing. Model checking, formal specification, and quantitative verification are presented in the contexts of conflict detection in autonomic computing policies, and of implementation of goal and utility-function policies in autonomic IT systems, respectively. Each of these techniques is illustrated using a detailed case study, and analysed to establish its merits and limitations. The analysis is then used as a basis for discussing the challenges and opportunities of this endeavour to transition the development of autonomic IT systems from the current practice of using ad-hoc methods and heuristic towards a more principled approach.

Specification, Development, and Verification of CASCADAS Autonomic Computing and Networking Toolkit

Increasing complexity, heterogeneity, and dynamism of current networks (telecommunications, ICT, and Internet) are making current computational and communication infrastructures brittle, inefficient, and almost unmanageable. As a matter of fact, computing and storage are progressively embedded in all sorts of nodes and devices that are interconnected through a variety of (wireless and wired) technologies in Networks of Networks (NoNs). Dynamicity, pervasivity, and interconnectivity of future NoNs will increase the complexity of their management, control, and optimization more and more, and will open new challenges for service delivery in such environments. Autonomic communications principles and technologies can provide effective computing and networking solutions overcome these bottlenecks and to foster such challenging evolution. This chapter presents the main concepts of an autonomic communications toolkit designed and developed in the EU project CASCADAS for creating and supervising service networking ecosystems, structured as ensembles of distributed and cooperating autonomic components. Moreover, it describes several use-cases developed for its validation and demonstration and reports the experimental results to assess the toolkit performances. A brief overview of future research directions concludes the chapter.