Systemics and Informatics World Network

Organization, Self-Organization, Autonomy and Emergence: Status and Challenges

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 1-9

Abstract: Development of IT-systems in application domains is facing an ever-growing complexity resulting from a continuous increase in dynamics of processes, applications- and run-time environments and scaling. The impact of this trend is amplified by the lack of central control structures. As a consequence, controlling this complexity and dynamics is one of the most challenging requirements of today’s system engineers.

The lack of a central control instance immediately raises the need for software systems which can react autonomously to changing environmental requirements and conditions. Therefore, a new paradigm is necessary how to build software systems changing radically the way one is used to think about systems and its development: self-organization, autonomy and emergence are the concepts that have to be build into future systems.

This paper shows first steps in order to arrive at a theory of self-organization, autonomy and emergence and provides some of the fundamental principles that should be followed for the design of truly adaptive software systems.

Keywords: systems theory, organization, self-organization, emergence, autonomy.

Harnessing Complexity: A Logical Approach to Engineering and Controlling Self-Organizing Systems

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 11-20

Abstract: In a complex dynamic system the centralized control and local monitoring of system behavior is not achievable by scaling up simple feedback adaptation and control models. This paper proposes using a variety of concepts from distributed artificial intelligence, random graph theory and statistical mechanics to logically model control in an abstract, complex system. An observer model is proposed to influence and monitor a system using organizational models that are known to engender certain large scale behavior from small scale interactions. The emergence of power law distributions in the connections between components is used to assess and control the system backbone comprising of hierarchically structured hubs. It is shown that such a system conforms to the generic prerequisites that tend a system to an optimal assembly, which is tolerant to failure. Additionally the deliberation to monitor the emergent control and the specification of the low-level interactions is handled through a common formalism, namely situation calculus. The approach is analyzed through a case study from a future NASA project.

Keywords: scaleable, autonomic, scale-free, propositional, decision theory, situation calculus.

Raphael M. Bahati, Michael A. Bauer, Chang-Won Ahn, O. K. Baek and Elvis M.Vieira

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 21-30

Abstract: Web-based applications are becoming key elements in the way many organizations deliver their services and provide support. Ensuring that expected performance and behavioral objectives are met is therefore critical. While there has been a lot of interest in applying classical feedback control theory to manage Web servers, the stochastic behavior of such systems compounded by complex interactions between the different tuning parameters, operational environment and load characteristics makes this task extremely daunting. On the other hand, policy-based management techniques offer flexible and adaptable means of dynamically changing systems’ and applications’ behavior without necessarily having to model the effects of the different possible configurations of the parameters. This paper looks at how such techniques can be applied to manage an Apache Web Server through the dynamic adjustment of tuning parameters. Several scenarios for evaluating the server’s performance are presented which show that meeting the different objectives, such as improving response time, throughput, and the efficient utilization of CPU and memory, could be achieved with few and relatively simple policies.

Keywords: autonomic management, policy-based management, web server management, self-configuration, self-tuning, Apache management.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 31-40

Abstract: Modern information systems are becoming more and more socio-technical systems, namely systems composed of human (social) agents and software (technical) systems operating together in a common environment. The structure of such systems has to evolve dynamically in response to the changes of the environment. When new requirements are introduced, when an actor leaves the system or when a new actor comes, the socio-technical structure needs to be redesigned and revised. In this paper, an approach to dynamic reconfiguration of a socio-technical system structure in response to internal or external changes is proposed. The approach is based on planning techniques for generating possible alternative configurations, and local strategies for their evaluation. The reconfiguration mechanism is presented, which makes the socio-technical system self-configuring, and the approach is discussed and analyzed on a simple case study.

Keywords: self-configuration, socio-technical systems, planning, local strategies

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 41-50

Abstract: The software industry is faced with the fast growing complexity of IT infrastructures. This makes manual administration increasingly difficult and appears to be the limiting factor in the general development of such infrastructures. This complexity crisis has stimulated many researchers to propose software systems that are allegedly self-organizing. However, often, this claim is only based on vague intuitions about self-organization, and a proper classification is missing. From a scientific standpoint, this is questionable and undesirable since it adds confusion rather than clarity. In this article, a framework is proposed that enables researchers to classify their systems and to state clearly, verifiably, and reproducibly why and in which way they are self-organizing. This framework provides a definition of the properties of a self-organizing system, it defines a respective class of systems denoted as SO, and it offers a methodology for proving that a given system is belonging to SO or to its complement SO. Some case studies of well-known existing software systems are presented to show that the methodology is useful and practically applicable.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 51-60

Abstract: An autonomic network must work unsupervised, therefore must be able to respond to unpredictable situations. The BIONETS project is working towards resilient network services that are able not only to perform short-term adaptations to the environment but also long-term evolution of new functionalities. To this end, a bio-inspired approach is proposed, based on an extension of evolutionary computing to a pervasive environment where disconnected operation is common, and where the fitness of a service is evaluated at runtime. Crossover or recombination of existing services occurs as opportunistic exchange of parameters or code, producing new generations of services which proliferate in the network or are discarded by a mechanism similar to natural selection.

In this paper we review the research lines related to autonomic service evolution currently in progress within BIONETS. A catalytic graph model describes the flow of opportunistic evolutionary interactions, shaped by cascade fitness evaluations. We present a research agenda and possible avenues leading to self-evolving services, and discuss their potential impact on future service engineering.

Keywords: service evolution, bio-inspired models, autonomic communications, evolutionary computing, catalysis, autonomic computing.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 61-69

Abstract: Organization is a central concept in systems. In this paper an ant algorithm for detecting organizations is presented. In a discrete-time context, at each time-step, an organization corresponds to a set of closely interacting entities in a system. This system is mapped to a graph where nodes represent entities and edges represent interrelations. Several colonies of ants compete, and inside each colony, ants collaborate in order to colonize the graph. Detected organizations emerge from the global behavior of the ants. The proposed approach is compared to other methods on a graph where the organizations are already known. It is then tested on two real world graphs studied in the related literature.

Keywords: Organization, community, dynamic graph, dynamic network, ant algorithm.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 71-79

Abstract: Nearly 20 years ago Denker, Schwartz et al. start one of their famous papers with the sentence: “Since antiquity, man has dreamed of building a device that would “learn from examples”, “form generalizations”, and “discover the rules” behind patterns in the data”. This paper will show a further step in turning this dream into reality.

Based on systems theory, especially on the framework of self-organization, a systematic approach how to build self-organizing networks based on a given set of trainings-data is shown. At first hand, the system is described in very general terms allowing application to a broad range of different networks. For a better understanding and in order to show the details, the approach is verified for the case of a 3-layer perceptron resulting in an algorithm that shows how to construct perceptrons having the ability to classify a given set of patterns correctly. Performance at the standard test example “two–or–more–clumps” is demonstrated.

Keywords: systems theory, self-organization, self-learning, artificial neural networks, multi-layer perceptron, feature detection, rule extraction.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 81-89

Abstract: Agent Oriented Software Engineering (AOSE) proposes the design of software systems as collections of autonomous agents, so-called Multi-Agent Systems (MAS). The autonomy of the interacting agents enables the rise of self-organized properties and emergent phenomena but challenges engineering efforts to predict, ensure and optimize these system wide, macroscopic properties. Since the construction of self-organized and emergent behaviors appears to contradict reductionist development strategies, current development approaches rely mainly on simulation and experiment of prototypes which use well understood coordination mechanisms. In this paper we argue that structured development processes for self-organizing MAS have to address the redesign and adjustment of agents using these established mechanisms. In order to facilitate agent redesign, we present a framework to describe MAS behaviors at different levels of granularity, focusing on the identification of how the exhibited agent behaviors contribute to the global arising structures. A proper understanding of the underlying coordination and collaboration mechanisms can guide enhancement and re-implementation for application development. A case study in collaborative sorting via simplified ants exemplifies our approach and leads to two improved redesigns.

Keywords: multi-agent system, self-organization, complex systems engineering paradox, redesign.

Alan Bivens, CheKim Chhuor, Donna Dillenberger, Pavitra Ghanta, Yuksel Gunal and Peter Yocom

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 91-97

Abstract: Systems and workload management frameworks have proven to be valuable utilities used to monitor and manage enterprise applications and the systems they run on. While these systems may have a great deal of knowledge about applications, they generally have little ability to control the rate at which applications receive work. In contrast, load balancers can control this rate, but typically have little information about the application’s ability to successfully handle the request. This paper describes recent efforts to unite these components in an autonomic manner for efficient, performance-oriented load balancing in enterprise environments. This paper will cover the interactions between these two components, an algorithm for autonomic, performance-based load balancing, and a brief case study involving this interaction with an enterprise application.

Reliability Self-Assessment in Reactive Autonomic Systems: Autonomic System-Time Reactive Model Approach

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 99-104

Abstract: This paper targets the reactive autonomic system’s self-monitoring of one of the most important non-functional properties, reliability. There are currently no adequate frameworks for tackling reliability in reactive and autonomic systems with self-monitoring functionality. The proposed in the paper reliability self-assessment of the Autonomic System Timed Reactive Model (AS-TRM) is based on the theory of Markov chains and is concerned with the uncertainty analysis of the AS-TRM as it evolves. An appropriate architecture for supporting reliability self-assessment is presented, along with a communication mechanism to implement the reactive and autonomic behavior. The reliability assessment is illustrated on a case study.

International Transactions on Systems Science and Applications, Vol. 2, No. 1, September 2006, pp. 105-110

Abstract: One of the key motivations for the provisioning of autonomic communication features in next generation services is to reduce the need of human interference for management tasks. This however means essentially that system control is delegated to the system itself, i.e., the system operator gives up control to a certain extent. The consequence is that autonomic systems might deviate from intended states and behaviors, may show inconsistent or unwanted ones. Based on Stafford Beer’s Viable System Model, in this paper a methodology is developed to define supervision structures as self-similar system enhancements to alleviate from those behaviors. The Viable System Model provides an intellectual and methodological framework for self-management in autonomic systems and allows for an understanding of the relationship of those control structures to the hierarchical organization of the supervised system.

Keywords: Viable System Model, autonomic system, self-management, pervasive supervision, self-similarity, system competence.

Agostino Forestiero, Raffaele Giordanelli, Carlo Mastroianni and Giandomenico Spezzano

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 111-122

Abstract: This paper proposes a self-organizing approach, based on ant-like agents, for the logical reorganization and the discovery of resources in Grids. Metadata documents describing Grid resources are replicated and disseminated on the Grid by ant-like agents, in such a way that documents related to the same class are accumulated in restricted regions of the Grid. A semi-informed discovery protocol drives query messages towards a region in which a large number of resources belonging to the requested class are maintained. Both agents and query messages travel the network according to a self-organizing mechanism, without having any information about the global system state, so guaranteeing scalability and robustness. Simulation analysis proves that the proposed approach allows for increasing the effectiveness of resource discovery, in terms of the mean number of discovered resources and time to collect them. This paper analyzes the impact that the granularity of resource categorization, i.e., the number of defined resource classes, has on performance results, and discusses benefits and drawbacks of having a more or less fine-grained resource categorization.

Keywords: agents, autonomous systems, grid, peer-to-peer, resource discovery, resource replication, swarm intelligence.

M. Baumgarten, N. Bicocchi, K. Curran, M. Mamei, M. Mulvenna, C. Nugent and F. Zambonelli

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 123-133

Abstract: The increasing ubiquity of sensing, computing and communication devices is forming the basis of a “smart world infrastructure”, with the potential to offer a panoply of innovative pervasive services. However, it also calls for such services to operate in a situation-aware and fully autonomic way. To achieve this, services would require a high degree of supporting knowledge about the social, computational, and physical environments in which they are situated, as well as self-knowledge about their own functionality. While the technology to acquire these types of knowledge is increasingly available, environments and services can actually get ‘smarter’ only via the availability of properly represented and widely accessible “networks of knowledge”, which can provide – via self-organization – for pruning, aggregating, correlating, the available knowledge, so as to facilitate their exploitation by components and services. In this paper, after having introduced the general vision of smart world infrastructures, we detail our idea of knowledge networks by outlining the characteristics that they should exhibit and by sketching a possible architectural approach for knowledge networks.

Keywords: knowledge networks, smart environments, self-organization, sensor networks.

Felipe Martins, Márcio Maia, Rossana M. de Castro Andrade, Aldri L. dos Santos and José Neuman de Souza

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 135-145

Abstract: The performance and dependability of grid computing can be affected due to manipulation of jobs results by malicious nodes. To assure correctness of applications, the grid environment needs to detect and isolate these kinds of nodes, self-organizing the set of available idoneous resources. This work presents a system-level diagnosis model based on comparison and reputation, which can be applied in several grid environments, as a strategy to avoid and minimize jobs results manipulation. This model settles the roles of the nodes according to their index of confidence, grouping them in autonomic logical clusters, where a hierarchy among the nodes is created to reach the diagnosis. Results achieved through simulation evaluate the model effectiveness in scenarios with different rates of malicious nodes.

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 147-156

Abstract: From the biology's point of view, pollination is an important step in the reproduction of seed plants. From the software engineer's view, pollination may evolve to a promising, biologically inspired paradigm for future, self-managing computing systems. This estimation is based on the self-* properties implied inherently by the pollination process between plants and insects. To exploit these characteristics for artificial, self-managing systems, this paper analyzes the components and sub-processes involved in the natural pollination process and identifies the emerging self-* properties. Based on that, the paper adapts this process by a formal specification for artificial pollination systems as well as a meta-model of their system architecture. The paper illustrates the adaptation's benefits by a case study and evaluates its capabilities and limitations. Finally, it presents open issues and an outlook on future work.

Keywords: self-management, self-organization, natural paradigm, autonomic computing, formal specification, system architecture.

Evolutionary Adaptation in Complex Systems Using the Example of a Logistics Problem

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 157-166

Abstract: There is a trend towards networked and distributed systems, complicating the design, construction and maintenance of complex software systems without any central control instance. This paper provides a solution to the problem of modeling and adaptation of complex adaptive systems (CAS). Here an agent based model is introduced to describe complex adaptive systems in order to study self-organization and adaptivity. An evolutionary computation (EC) enabled multi-agent system (MAS) is used that exploits the flow of money or energy in order to realize distributed fitness calculation. Our approach uses fully decentralized operators for reproduction like mutation, recombination and selection, regulated by market mechanisms. This paper presents two general outcomes of our model: how adaptation occurs in the number and strategies of agents leading to an improvement at the system level. The novelty of this approach lies in the biology-inspired bottom-up adaptation method for decentralized systems that is intended to be general for a wide variety of artificial systems. As an example of complex adaptive systems, a logistics network is introduced and used to study the expected results.

Keywords: multi-agent systems, adaptation/self-adaptation, local search, artificial life, complex adaptive systems, evolutionary computation.

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 167-175

Abstract: Service-oriented Grid is quickly shaping towards a utility market with players such as end-users, brokers and service providers co-operatively working together. End-users wish to use functionality of Grid services by paying the minimum possible price or price confined within a specified budget, brokers aim to maximize profit whilst satisfying end-user needs and resisting the uncertainty that prevails within a Grid and service providers aim to develop price models based on end-user demands that will maximize their profit. We develop a novel method for Grid brokers that aims at maximizing profit whilst satisfying end-user needs with a sufficient guarantee in a volatile utility Grid. We propose in this paper an approach for generating constraint equations describing the workflow, the Quality of Service (QoS) requirements and the state of the Grid. This set of equations may be solved using Mixed-Integer Linear Programming (MILP), which is the traditional method. We further develop a 2-stage stochastic MILP which is capable of dealing with the volatile nature of the Grid and obtaining cost bounds that ensure that end-user cost is minimized or satisfied and broker's profit is maximized with sufficient guarantee. These bounds help brokers know beforehand whether the budget limits of end-users can be satisfied and if not then obtain appropriate future leases from service providers. Experimental results confirm the efficacy of our approach.

A Video Pre-Classification Method with Multi-Layer Self-Organizing Maps and Principal Component Analysis

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 177-183

Abstract: Motion information is important to describe video. In order to pre-classify video well, a good classifier is needed to distinguish P frames of global and local motions. In this paper, according to coding characteristics of MPEG, a novel algorithm called MPCA-MSOM is used as the classifier, which is a combination of multi-layer self-organizing map (SOM) and principal component analysis (PCA). In the MPCA-MSOM algorithm, the imprecise clustering in the traditional SOM algorithm is subdivided layer by layer. In addition, PCA is used to select features. Experimental results show that the MPCA-MSOM algorithm increases recognition ratio, and works better than the other methods.

Keywords: multi-layer self-organizing map, principal component analysis, global motion, local motion, video retrieval.

Real-Time Analysis to Ensure Deterministic Behavior in a Modular Robot Based on an OSEK System

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 185-190

Abstract: In this paper, a real-time analysis is proposed to design an autonomous and modular robot having self-reconfiguration and self-assembly capabilities and deterministic behavior. The ability of a modular robot to meet its mission strongly depends on the artificial intelligence software. The artificial intelligence software of a robot is mapped into several elementary tasks with different real-time constraints. The real-time analysis, proposed in this paper, takes into account kernel overheads for the validation of the real-time behavior of an artificial intelligence software. This real-time analysis is based on the OSEK operating system that requires few hardware resources and is cost effective. The kernel overheads are identified, characterized, and taken into account in the feasibility conditions. The theoretical worst case response times obtained with kernel overheads are compared to the response times obtained on a task set on a real robot, based on the event driven OSEK implementation. This comparison shows that the kernel overheads cannot be neglected and that the theoretical results are valid and can be used to ensure a deterministic behavior of the robot.

Keywords: modular robotic, artificial intelligence, OSEK, real-time, feasibility conditions, kernel overheads.

System-on-Chip Design of a Fuzzy Logic Controller Based on Dynamically Reconfigurable Hardware

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 191-196

Abstract: Fuzzy Logic is, nowadays, a control technique widely extended in nonlinear system applications. This work adds a new point-of-view to the continuous efforts in search of an optimized hardware-software co-design of a dual-input single-output fuzzy logic controller (FLC). Our approach breaks up with the classical three-stage implementation process - fuzzification, rule inference and defuzzification cores - to focus it on directly synthesizing the resultant control surface. An innovative design methodology is defined by firstly splitting the total area in rectangular sectors to, afterwards, model each of them by second-order polynomial functions. The algorithm is finally embedded in a MCU-FPGA platform to achieve a balanced cost-performance solution inspired by such efficient concepts in terms of run-time and silicon-area as parallel processing and dynamic partial reconfiguration, respectively. The result is a universal FLC where the control surface is parameterized and handled through a simple data file appended to the design bitstream in the way of initialized SRAM memory. This HW/SW architecture therefore provides a general-purpose solution able to customize whichever fuzzy application by only updating the data that model the particular control surface segmented in rectangular sectors.

Keywords: fuzzy logic, hardware-software co-design, dynamically reconfigurable FPGA, system-on-chip.

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 197-202

Abstract: This paper proposes an agent-oriented formal modeling framework for grid application, Formal AOMG (Agent-Oriented Modeling based on Grid). Based on Object-Z language, Formal AOMG integrates meta-models from i* framework and UML, and introduces a new intention attribute, service attribute, into agent. Formal AOMG models the agent in grid environment as a service depender or dependee. Three core models of Formal AOMG, Organization Model, Agent Class Model and Agent Service Model are presented. This paper illustrates the usability and efficiency of Formal AOMG through modeling an example of grid application, a distributed internet order system.

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 203-207

Abstract: Since its creation in 1990, World Wide Web has increased the popularity of Internet which becomes an important source of information or services for all people over the world. The dynamic nature of the Web draws attention to the need for continuous support and updating of Web information retrieval systems. Web crawling is the process of discovery and maintenance of large-scale web data. Crawlers achieve this process by following the Web pages hyperlinks to automatically download a partial snapshot of the Web. In this paper, an agent-based approach, through three scenarios, for parallel and distributed Web crawling is presented. Simulations with ns2 show that the cloning based mobile agents scenario outperforms the single and multiple mobile agents scenarios.

Keywords: web crawling, mobile agent, agent cloning, self-regulation, parallel random walk.

A Self-Governance Approach to Supporting Privacy Preference-Based Content Sharing

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 209-213

Abstract: The increase in the creation and sharing of distributed multimedia content has led to the creation of new tools and methods to automatically and manually annotate content to assist in multimedia management. The content is often shared within communities and the owner has very little means to protect their content from misuse. This can become a problem when the annotations (metadata) are attached to the content as they provide more personal meaning to the content and thus can lead to privacy concerns. However, there are no tools available to manage content in the way it was intended to be used e.g. carrying privacy preference intention with the content and assisting the user in creating appropriate content access preferences with their community. This paper provides an overview of the issues faced in distributed personal content management from a user view, the current state of the art to deal with the increasing risk in privacy issues for the digital user, and the design of contextual information and self-governance method applied. An overview of the distributed framework used for large scale content management and the deployment of the self-governance implementation is provided. Finally, some preliminary conclusions are given.

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 215-219

Abstract: Methods from formal specification and verification have been successfully applied to the description of complex and reactive systems. It can be observed however that these methods lead to monolithic models which describe important aspects of behavior but do not provide the flexibility and adaptivity which is necessary to cope with reactive behavior and environmental conditions. These adaptive properties are naturally provided by meta-heuristics which simulate the capabilities of natural processes (e.g. ant colony algorithms). This article proposes a hybrid framework which combines the power of automatic reasoning with ant colony algorithms in order to combine the positive aspects from both research areas. It is demonstrated how to combine robust and inexpensive verification algorithms with the adaptivity of virtual ant colonies. This synthesis can be considered as a contribution to context-awareness of complex systems and to autonomic computing.

Keywords: ant colony optimization, tuple tree automata, fuzzy description logics, high-level specification, context-awareness.

Selfish Motivated Cooperative Planning in Cross Networked Mechatronic System

International Transactions on Systems Science and Applications, Vol. 2, No. 2, September 2006, pp. 221-225

Abstract: Coordination of mechatronic systems will raise the level of utility of such products. To realize the maximum gain of utility, it is not enough to coordinate just the current actions of the mechatronic systems. Only a forward looking coordination can alter future actions of mechatronic systems in order to realize synergy effects. It is assumed that mechatronic systems act autonomous and maybe act selfish, for instance due to their owner. For this reason the application of centralized systems is not suitable. This idea leads directly to multiagent planning. This paper introduces the first steps on a way to a cooperative planning system for mechatronic systems.

Keywords: self-optimization, cooperative multiagent planning, selfish systems.

A Distributed Structure for Service Description Forwarding in Mobile Ad-Hoc Networks

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 227-244

Abstract: In this paper we describe a distributed data structure that is used to propagate service descriptions in multi-agent systems where agents connect to each other using a volatile (e.g., wireless) multi-hop network. We describe a simple structure, akin to a spanning tree, called the Core Based Tree (CBT), that can be constructed and maintained easily even in face of the network volatility, which provides a pathway for propagating the service descriptions. For service description to work we require that agents describe the services that they provide and the services that they need, and give a basic algorithm that uses the CBT to propagate descriptions so as to guarantee that matches are found if they exist. We give an estimate of the stretch of the constructed CBT and the message complexity of the CBT construction algorithm.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 245-254

Abstract: The advent and proliferation of Service-oriented Architectures (SOA) drives computing infrastructures into a highly interconnected, heterogeneous, and dynamic world. Conventional management tools fail in the attempt to deal with the heterogeneity and the dynamics associated with this type of information infrastructures. More and more researchers try to cope with the complexity, heterogeneity, and uncertainty by using technologies inspired by biological systems. A promising approach for managing such large-scale IT infrastructure is to provide capabilities for self-organization, which – to some extent – is analogous to the human autonomic system (as postulated in IBM’s Autonomic Computing Initiative and as extended in the German Organic Computing Initiative). This paper outlines a common view on Autonomic Service-oriented Architectures and proposes a way to get such an autonomic infrastructure. An outline of the differences between autonomic service-oriented architectures and other systems with autonomic properties is followed by a discussion of the existing enabling technologies and of missing pieces on the roadmap to a self-organizing infrastructure.

Towards Autonomous Management of QoS through Model-Driven Adaptability in Communication-Centric Systems

Christophe Chassot, K. Guennoun, Khalil Drira, François Armando, Ernesto Exposito and André Lozes

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 255-264

Abstract: Automated management of QoS provisioning enables mastering the complexity of mechanisms that implement run-time adaptation actions. Providing efficient solutions requires handling of adaptability not only at the behavioral level, but also at the architectural level. Most of existing standard solutions focus on the behavioral level using reconfiguration mechanisms. This paper proposes models providing adaptability actions at the architectural level. Different abstraction levels are distinguished. Their architectural styles and mapping rules using graph grammars and graph transformations are formally defined. The proposed approach is illustrated through a case study dealing with military emergency operations.

Keywords: self-adaptability, QoS, model-based automated management, service-oriented dynamic architecture, group communication application, graph grammar.

Self-Optimization Quality of Service by Adaptive Routing in Dynamic Communication Networks

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 265-272

Abstract: In the last decade, due to emerging real-time and multimedia applications, efficient routing of information packets in dynamically changing communication network requires that as the load levels, traffic patterns and topology of the network change, the routing policy also adapts. We focused in this paper on QoS self-optimization by developing a neuro-dynamic programming to construct dynamic state-dependent routing policies. In this paper, we propose an approach based on adaptive algorithm for packet routing using reinforcement learning called N best optimal path Q Routing Algorithm (NORA). To improve the mechanism of multipath routing used in NORA, we add also a module in order to compute dynamically a probabilistic traffic path distribution. The performance of our algorithm is evaluated experimentally with OPNET simulator for different levels of traffic’s load and compared to standard shortest path and Q-routing algorithms. Our approach prove superior to a classical algorithms and is able to route efficiently in large networks even when critical aspects, such as the link broken network, are allowed to vary dynamically.

Keywords: Self-Optimization Routing Decision, Quality of Service based Routing, Multi Path Routing, Dynamic Network, and High Irregular Traffic.

Exploring Transport Layer Solutions for Parallelism and Load Balancing within Internet Service Clusters

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 273-280

Abstract: Within the Internet clustered service paradigm the dispatcher cluster approach is widely used because of its good overall performance. The operational design of a cluster dispatcher is meaningfully analyzed in terms of the Open Systems Interconnection (OSI) layer at which the dispatcher’s load balancing and scheduling operational logic is implemented. Whilst existing dispatcher operational designs occupy layer 2 (Data Link Layer), layer 3 (Network Layer), and layer 7 (Applications Layer) – there has been no theorizing and prototyping of a layer 4 (Transport layer) solution. This paper describes an experiment in designing, implementing and testing a Transport layer cluster scheduling and dispatching architecture that specifically aims to improve cluster dispatcher efficiency. The Transport layer architecture centers upon two new Transport Control Protocol (TCP) options and an expanded Application Programming Interface (API). The prototype from this research has been implemented within the Linux (2.4) kernel confirms the operational efficiency of the solution.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 281-288

Abstract: Nowadays, several multimedia formats are available, thus users need to use the proper player for a given content. Moreover, when a multimedia stream coming through the network is played, the timing characteristics of the network can affect the quality of the reproduction. To fit both player and network capabilities, it is sometimes appropriate to transform the content before sending it through the network. In this paper, we analyze the issues concerning multimedia content transformation with a view to ensuring a smooth reproduction of the intended content at the client side. For this purpose, we propose an architecture that can take advantage of a Grid system in order to support content adaptation. In our proposal, content adaptation is performed through appropriate agents that are allocated as jobs and executed on Grid hosts. A location service is therefore devised and made available within the Grid system, which helps finding the hosts whose geographic position and network connections minimize the delays required to move the desired multimedia content from the storage to the processing site, and (after suitable transcoding) from this to the requesting client.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 289-295

Abstract: In this paper, we present how we extended the management system in JOnAS, an open source J2EE application server to introduce autonomic functions. This work required minimal modifications in the application server and is based on a standard component model, JMX. Therefore, our solution can be easily generalized to other application servers or JMX-based systems. To illustrate our approach, we describe a self-recovery experience we held in a J2EE cluster and we discuss the benefits and the drawbacks of our solution.

Keywords: distributed systems management, architecture-based management, J2EE application server, autonomic computing.

Graphically Designing and Formally Checking Self-Organizations for Wireless Network Systems

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 297-302

Abstract: This article presents a methodology suitable for analyzing self-organizing systems. The advocated methodology consists to model graphically the problem and verify it formally with B method. The methodology is constituted of three stages. The first one deals with using new model adapted at a self-organizing structure. That stage allows for a more intuitive description of the system’s behavior. The second one deals with translation rules that enable to go from the graphic model to a formal system specification. The third stage deals with the formal verification of the self-organizing process. The proposed methodology is presented via the example of a self-organizing algorithm, where roles played by agents are at the heart of the self-organization itself.

Keywords: self-organization, formal specifications, graphical methods, multi-agent systems, wireless network.

The CASCADAS Project: A Vision of Autonomic Self-organizing Component-ware for ICT Services

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 303-308

Abstract: Autonomic computing and communications provides a basis for situated and self-aware service provision beyond that currently available, but also raises need demands in understanding how to organize, supervise and manage such service provision. This paper reports on the CASCADAS project, which brings together researchers in diverse areas to develop component-ware for such autonomic and adaptable services, and describes how the project relates to the wider theme of autonomic and situated solutions for Information and Communications Technology (ICT) services.

Keywords: Autonomic, self-organizing, self-aggregating, self-similar, situated, components.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 309-313

Abstract: A self-organizing method to solve complex optimization problems as a graph vertex coloring is proposed in this paper. The self-organizing approach is needed in the environment of ad hoc networks because there is no central management and the network nodes can use only local information. The solution can be found only by local interaction between the system components without any help from outside. The proposed method is inspired by the chemical casting model but it is extended and more generalized. The method's accuracy is tested with instance graphs.

Steering and Evaluating Autonomic Deployment of Service Components in a P2P Network

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 315-318

Abstract: In this paper, local decision rules for autonomic service deployment, based on nonlinear dynamics and regulatory feedback loops leading to task allocation or differentiation, are presented. A description of a methodology to study global system dynamics and make quantitative predictions about service availability in a peer-to-peer community governed by these rules is described. A population of identical peers, connected through an overlay of variable topology is hypothesized. Every peer is assumed to need access to the same service components and to be able to change allocation of its local resources so as to specialize into performing only certain tasks, corresponding to a subset of all components. Coordination of this differentiation process is enabled by the ability to delegate execution of a task to the most capable first neighbor (with respect to performing that particular type of task) and by the use of lateral inhibitory signaling to prevent simultaneous specialization of first neighbors into the same task.

Keywords: self-organization, task allocation, differentiation, overlay network, service provision, peer to peer community.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 319-322

Abstract: This paper proposes a new optimal control algorithm appropriately to multimedia traffic in IEEE 802.11e WLAN (Wireless LAN) and describes control procedure of the algorithm based on Markov process analysis. The algorithm applies optimization policy to assign idle channel for the different priority traffics with heterogeneous characteristics. Compared with DCF (Distributed Coordination Function) method, the result of simulation indicates that the new method decreases the overhead of frame collision detection and retransmission caused by CSMA/CA mechanism meanwhile increases access efficiency. The algorithm utilizes wireless resource effectively and enhances the service performance of the system.

Keywords: wireless LAN, medium access channel, markov process, optimization policy.

A Threshold-Based Energy Efficient Routing Protocol for Wireless Sensor Networks

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 323-327

Abstract: The Threshold - Based Energy Efficient Routing Protocol (TBEERP) for Wireless Sensor Networks is presented in this paper. In the scheme, hard and soft threshold are set, and the data collected by sensor nodes are forwarded only if they are higher than the threshold value. The energy level of each node is broadcasted to all neighbors periodically and each individual node makes routing decisions according to a routing algorithm, which is sensitive to the residual energy level of the node. To prevent the node from receiving duplicate data, a route set which is composed of the nodes on the route is deployed and then the node only chose the neighbor node that is not in route set. To insure that the network delay is not too long, a parameter Ts is set. If the delay is longer than Ts, the data are dropped. To prolong the life time of the network, the activity of an exhausting node is reduced. Simulation results show that such routing mechanism has high robustness in terms of packet delivery ratio even in harsh link conditions. This scheme allows network planners to influence the routing decisions for adapting to a variety of network scenarios by adjusting parameters.

International Transactions on Systems Science and Applications, Vol. 2, No. 3, September 2006, pp. 329-332

Abstract: A region-based multi-path routing algorithm for mobile Ad Hoc networks (MANET) is developed in this article. The algorithm limits route discovery activities within a predefined region between source node and destination node. Compared with conventional routing algorithm, not only is route overhead reduced, but also the optimal route is ensured. Performance analysis and simulations show that TCP throughput, route overhead and delay is greatly improved in high-speed mobile and dynamical network environment by the selection of appropriate multi-path routing policies.

VODCA: View-Oriented, Distributed, Cluster-Based Approach to Parallel Computing

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 333-345

Abstract: This paper presents a high-performance Distributed Shared Memory system called VODCA, which supports a novel View-Oriented Parallel Programming on cluster computers. One advantage of View-Oriented Parallel Programming is that it allows the programmer to participate in performance optimization through wise partitioning of the shared data into views. Another advantage of this programming style is that it enables the underlying Distributed Shared Memory system to optimize consistency maintenance. VODCA implements a View-based Consistency model and uses an efficient View-Oriented Update Protocol with Integrated Diff to maintain consistency of a view. Important implementation details of VODCA are described in this paper. Experimental results demonstrate that VODCA performs very well and its performance is comparable with MPI (Message Passing Interface) systems.

Keywords: cluster computing, distributed shared memory, message passing interface, parallel computing, view-based consistency, view-oriented parallel programming, VODCA.

Heterogeneous Swarm Formation Control with Potential Fields Formed by Bivariate Normal Functions

Laura Barnes, Wendy Alvis, MaryAnne Fields, Kimon Valavanis and Wilifredo Moreno

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 346-359

Abstract: A novel method is presented for dynamic heterogeneous swarm formation control with potential fields generated from bivariate normal probability density functions (pdfs). These functions are used to construct the surface swarm members move upon, controlling swarm geometry, individual member spacing, and managing obstacle avoidance. Limiting functions are defined to provide tighter swarm control by modifying and adjusting a set of control variables forcing the swarm to behave according to set constraints. Bivariate normal functions and limiting functions are combined to guarantee obstacle avoidance and control swarm member orientation and swarm movement as a whole. This approach compared to others, is simple, computationally efficient, scales well to different swarm sizes, to heterogeneous systems, and to both centralized and decentralized swarm models. The method is applied to a simple vehicle model and simulation results are presented for homogeneous and heterogeneous swarms of four and ten robot vehicles following line and ellipse formations.

Software Engineering Approach to Developing Agents for Electricity E-commerce

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 360-370

Abstract: Just recently, agent software has been gaining grounds through deployment in several application areas. Agents have many advantageous features including adaptability, intelligence, self-initiation, collaborative nature, and mobility. Consequently, the area of agent software engineering has very recently emerged to define process models and guidelines to facilitate the development of agent software. This paper presents an ICAPS (Incremental Component-Assembly with Prototyping over the Spiral)-based software engineering process to developing agents that specifically perform electricity e-commerce. Such an application has come under high demand lately due to the global trend in electricity restructuring. Electricity trade will eventually evolve into some type of an electronic commerce structure, possibly managed by a group of collaborative agents that work according to standard regulations and severe operational and security constraints. The results of the test case show that agents facilitate electronic trade and drive the market price closer to the marginal cost of generation supply.

A Distributed Agile Electronic Performance Support System with Software Agents and Service Oriented Architecture from Design to Implementation

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 371-390

Abstract: Electronic Performance Support Systems (EPSS) are complex software that are frequently required to adapt to rapid changes in information content. The conventional practice of issuing a new release on discrete intervals to accommodate changes cannot keep up with the current pace of change and is not satisfactory in dealing with modern requirements. In this paper, we discuss how the concept of service oriented architecture (SOA) combined with software agents can result in an agile EPSS that reacts to changes by dynamically extracting current information from information sources distributed over an enterprise. Following a model driven approach, we present a conceptual anthropomorphic model and then, to aid in the development of such a complex software system, an approach to the architectural design is provided which is amenable to standard software engineering practices. In so doing, we develop an algorithm to transform UML state chart model of an agent into an Object Coloured Petri Net in order to construct a Petri Net model of the system for dynamic analysis. Simulation and analysis results are discussed along with some implementation details.

Keywords: agile EPSS, enterprise information systems, service oriented architecture, software agents.

An Ontology-based Adaptive Approach to P2P Resource Discovery in Distributed Scientific Communities

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 391-404

Abstract: Resource discovery is a challenge in a distributed environment. Trade-off is often needed between the speed and the accuracy of findings. There are two parts to resource discovery: the routing and matching of a query. This paper presents an adaptive approach to peer-to-peer (P2P) resource discovery which separates the routing of queries from the query matching mechanism. It focuses on improving the efficiency of routing search queries to increase the quality of the search results and also the scalability of the resource discovery in a highly decentralized P2P environment. This separation enables the adoption of any appropriate query matching/processing methods at a later stage. Three properties of scientific research communities provide the grounding for the approach: the existence of common interest groups, the willingness to share resources of common interests and the transitive relationship in the sharing behavior. The use of ontology enables ‘learning’ from past results and for providing guidance in future searches. By exploiting these features, the quality of search results can be improved and the network traffic reduced. Experimental results have provided some evidence to confirm the efficiency gain of this adaptive approach.

Initialization for Multi-Robot Formations with Virtual-Head Robot Tracking and Three-Point l-l Control

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 405-412

Abstract: Robotic formation is a group of mobile robots coordinated to get into and maintain a certain geometric shape. This paper presents an effective methodology for initialization of mobile robots to establish desired formation shapes. To enter a formation pattern from arbitrary positions, virtual head robot tracking is proposed for two robots and three-point l-l control for three robots. These controllers are incorporated with reactive control schemes to achieve inter-robot collision avoidance. A generic procedure is suggested to deploy multiple robots into a desired shape. Advantages of our approach include the establishment and maintenance of any formation type from arbitrary initial conditions with collision avoidance for a large group of mobile robots. Extensive simulation results are provided to illustrate the capability of handling singularities and avoiding inter-robot collision in a group of N robots.

Keywords: collision avoidance, formation, three-point l-l control, virtual head robot.

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 413-420

Abstract: In the field of data mining, classification problems such as pattern recognition and biometric identification, have been studied extensively. In this paper, a novel classification approach has been presented which utilizes a multi-perspective representation (MPR) method that takes advantage of the synergy of multiple representations of an information object. A detailed description of how to integrate the MPR scheme with Support Vector Machine (MPR-SVM) is provided. Support Vector Machine (SVM) is considered to be a very effective classification tool, which has been applied to a wide range of applications. The reported results of the experiments conducted on four benchmark data sets demonstrate the applicability and effectiveness of using the MPR-SVM scheme for classification purposes.

keywords: classification, data mining, multi-perspective representation method, support vector machine.

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 421-426

Abstract: Software maintenance is an important activity performed in the software life cycle. One of the major concerns in the management of maintenance is to understand and predict the maintenance effort in order to efficiently allocate the resources. This paper presents a software maintenance effort model in which the maintenance effort is divided into the programmer effort and the supporting effort. The programmer effort contains isolation effort, modification effort, and testing effort, while the supporting effort includes management effort and service effort. Through an empirical study, this paper (1) examines the distributions of different programmer efforts; (2) analyzes a linear model to predict the testing effort; and (3) studies the relations between the programmer effort and the supporting effort.

Framework for Mobile Grid Computing by Hybridizing Structural and Un-structural P2P Technologies

International Transactions on Systems Science and Applications, Vol. 2, No. 4, February 2007, pp. 427-432

Abstract: This paper presents a framework for P2P-mobile grid computing based on P2P technologies. The framework contains the core network and surrounding network. The core network hybridizes structural and unstructureal P2P technologies by merging n-tuple replicated virtual tree structured route nodes and randomly cached un-structured route nodes. The surrounding network usually consists of clients such as mobile phone, PDA, etc. The framework uses mobile IP technology to enable clients mobility. This paper also presents software architecture and primary implementation of the framework.

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