Mobile agent-enabled framework for structuring and building distributed systems on the internet

Mobile agent has shown its promise as a powerful means to complement and enhance existing technology in various application areas. In particular, existing work has demonstrated that MA can simplify the development and improve the performance of certain classes of distributed applications, especially for those running on a wide-area, heterogeneous, and dynamic networking environment like the Internet. In our previous work, we extended the application of MA to the design of distributed control functions, which require the maintenance of logical relationship among and/or coordination of proc- essing entities in a distributed system. A novel framework is presented for structuring and building distributed systems, which use cooperating mobile agents as an aid to carry out coordination and cooperation tasks in distributed systems. The framework has been used for designing various distributed control functions such as load balancing and mutual ex- clusion in our previous work. In this paper, we use the framework to propose a novel ap- proach to detecting deadlocks in distributed system by using mobile agents, which dem- onstrates the advantage of being adaptive and flexible of mobile agents. We first describe the MAEDD (Mobile Agent Enabled Deadlock Detection) scheme, in which mobile agents are dispatched to collect and analyze deadlock information distributed across the network sites and, based on the analysis, to detect and resolve deadlocks. Then the design of an adaptive hybrid algorithm derived from the framework is presented. The algorithm can dynamically adapt itself to the changes in system state by using different deadlock detec- tion strategies. The performance of the proposed algorithm has been evaluated using simulations. The results show that the algorithm can outperform existing algorithms that use a fixed deadlock detection strategy.     

M&M's: Building Binary Software Components for Supporting Mobile-Agent Enabled Applications

Mobile Agents provide a new promising paradigm for developing distributed applications. Nevertheless, although the basic concept has been around for some years and many agent platforms are available both from the industry and research community, there are currently few examples where the technology has been deployed in the real world. One important reason for this is that using the current available agent frameworks it is quite difficult to develop applications without having to center them completely on the agents and on the agent infrastructure. In this paper, we present the M&M project, taking place at the University of Coimbra. In this project, we are developing an extensive component-based framework that enables ordinary applications to use mobile agents in a flexible and easy way. By using this approach, applications can be developed using current object-oriented approaches and become able of sending and receiving agents by the simple drag-and-drop of mobility components. The framework was implemented using the JavaBeans component model and provides integration with ActiveX, which allows applications to be written in a wide variety of programming languages. By using this framework, the development of applications that can make use of mobile regents is greatly simplified, which can contribute to a wider spreading of the mobile agent technology.     

The ECORA framework: A hybrid architecture for context-oriented pervasive computing

An infrastructure approach to support context-aware pervasive computing is advantageous for rapid prototyping of context-aware distributed applications and beneficial for unifying modelling of context and reasoning in uncertain conditions. This paper presents the ECORA framework for context-aware computing, which is designed with a focus on reasoning about context under uncertainty and addressing issues of heterogeneity, scalability, communication and usability. The framework follows an agent-oriented hybrid approach, combining centralized reasoning services with context-aware, reasoning capable mobile software agents. The use of a centralized reasoning engine provides powerful reasoning capabilities and deploying context-aware mobile agents enables agility and robustness of components in the pervasive system. The design and implementation of the framework at different levels, as well as three case studies, are presented.     

An adaptive framework for monitoring agent organizations

Multiagent technologies are usually considered to be suitable for constructing agent organizations that are capable of running in dynamic and distributed environments and that are able to adapt to changes as the system runs. The necessary condition for this adaptation ability is to make agents aware of significant changes in both the environment and the organization. This paper presents mechanism, which helps agents detecting adaptation requirements dynamically at run time, and an Trace&Trigger, which is an adaptation framework for agent organizations. It consists of an event-tracing-based monitoring mechanism that provides organizational agents with information related to the costs and benefits of carrying out an adaptation process at each moment of the execution. This framework intends to overcome some of the problems that are present in other approaches by allowing the dynamic specification of the information that has to be retrieved by each agent at each moment for adaptation deliberation, avoiding the transference of useless information for adaptation deliberation. This framework has been integrated in the Magentix2 multiagent platform. In order to test its performance benefits for any agent organization, an example based on a market scenario is also presented.     

Distributed computing paradigms for collaborative signal and information processing in sensor networks

In this paper, we report the development of an energy-efficient, high-performance distributed computing paradigm to carry out Collaborative Signal and Information Processing (CSIP) in sensor networks using mobile agents. In this paradigm, the processing code is moved to the sensor nodes through mobile agents, in contrast to the client/server-based computing, where local data are transferred to a processing center. Although the client/server paradigm has been widely used in distributed computing, the many advantages of the mobile agent paradigm make it more suitable for sensor networks. The paper first presents simulation models for both the client/server paradigm and the mobile agent paradigm. We use the execution time, energy and energy*delay as metrics to measure the performance. Several experiments are designed to show the effect of different parameters on the performance of the paradigms. Experimental results show that the mobile agent paradigm performs much better when the number of nodes is large while the client/server paradigm is advantageous when the number of nodes is small. Based on this observation, we then propose a cluster-based hybrid computing paradigm to combine the advantages of these two paradigms. There are two schemes in this paradigm and simulation results show that there is always one scheme which performs better than either the client/server or the mobile agent paradigms. Thus, the cluster-based hybrid computing provides an energy-efficient and high-performance solution to CSIP.     

Data Privacy in Tuple Space Based Mobile Agent Systems

More recently, distributed variants of tuple spaces have been proposed to exploit the Linda model for programming distributed applications over wide area networks, possibly exploiting code mobility. However, the flexibility of the shared tuple space model opens possible security holes; it basically provides no access protection to the shared data. In this paper we investigate some possible scenarios where mobile agents can benefit from our cryptographic tuple space based framework, CryptoKlava, and sketch how to possibly implement such agents in order to keep the privacy of items collected by the mobile agent during its itinerary. The functionalities of the framework are general enough to be applied to other Java frameworks using multiple distributed tuples spaces possibly dealing with code mobility.     

Applications of mobile agents and ambassadors in distributed simulation

This paper describes part of a project to investigate various uses of mobile agents within distributed simulations. A number of generic roles for these agents are suggested. The design of a monitoring facility for remote models is covered in detail. This has been constructed as an example of an “Ambassador system”, having a convenient sub-set of the facilities of a fully autonomous mobile agent system. The prototype of this system uses Java applets to provide model-specific controls and displays through a standard Internet browser interface.     

A PK-SIM card based end-to-end security framework for SMS

Since the first SMS (Short Message Services) message was sent in the UK in 1992, the SMS has become a mass communication tool and has been broadly used in mobile business applications. But the security issue of the SMS has often been considered as a crucial barrier to its application in many fields that need strong authentication and confidentiality, such as mobile-commerce. The Subscriber Identity Module (SIM) inside mobile phones is a tamper resistant device which contains strong authentication mechanism and has been used in remote user authentication system, e.g. WIM¹ card in Wireless Application Protocol (WAP). In this contribution, we design and realize a secure SIM card, named PK-SIM card, which is a standard SIM card with additional PKI functionality; based on the PK-SIM card, we present a security framework offering solutions for the development of secure mobile business applications using SMS as bearer. The security framework consists of a client device, in which a PK-SIM card is used to store security credentials, a Secure Access Gateway (SAG) which is used to receive and send secure SMS messages, a trusted third-party, Certification Authority (CA), which provides a public-key certification service and a Mobile Operator which provides the communication infrastructure for the SMS. Then we propose an authentication and session key distribution protocol which provides end-to-end security between the PK-SIM card and the SAG, and give a formal security analysis to the proposed protocol based on BAN authentication logic². Lastly, we provide a typical application of the security framework in Mobile Police Information System. The evaluations of the system have proved that the security framework is suitable for actual needs both in speed and security.     

Mole – Concepts of a mobile agent system

Due to its salient properties, mobile agent technology has received a rapidly growing attention over the last few years. Many developments of mobile agent systems are under way in both academic and industrial environments. In addition, there are already various efforts to standardize mobile agent facilities and architectures. Mole is the first mobile agent system that has been developed in the Java language. The first version was finished in 1995, and since then Mole has been constantly improved. Mole provides a stable environment for the development and usage of mobile agents in the area of distributed applications. In this paper we describe the basic concepts of a mobile agent system, i.e., mobility, communication and security, discuss different implementation techniques, present the decisions made in Mole and give an overview of the system services implemented in Mole.     

FARM: file annotation and retrieval on mobile devices

As the technology evolves, mobile phones and portable devices are equipped with advanced features like built-in cameras, audio/video recordings, and other applications. When a user starts utilizing such features and applications, usually a large number of files are generated, and as this number grows, it becomes a challenging task to find the requested files with limited user-interface capabilities. This article presents FARM, a framework for file annotation and retrieval on resource-limited mobile devices like mobile phones, PDAs, and other MIDP compliant devices. Once the annotation process is completed, user can easily retrieve the files on the device itself or on in a networked environment where a large number of mobile nodes are involved. The metadata for annotation is gathered from the underlying file system and stored locally, which gives this framework a two-fold gain. Firstly, this framework does not require any common repository and hence, does not require communication medium to store and retrieve metadata. Secondly, searches are performed in a distributed fashion when more than one device is searched. The proposed framework has been implemented with a full featured application, and experimental results show that files can be retrieved efficiently and accurately with annotated data.     

一种基于移动代理的入侵检测系统模型

提出一种利用IBM Aglet平台构建基于移动代理的分布式入侵检测系统模型，利用移动代理的移动性、灵活性、适应性、跨平台性和代码可重用等特性来克服目前入侵检测系统中存在的效率低、可移植性差、灵活性(包括可调整性、伸缩性和动态重新配置能力)有限和升级能力有限等缺陷。     

用于协作信息处理的基组织结构模型

文中提出了大型互联网络上支持复杂协作策略的基组织结构模型（ＢａｓｉｃＯｒａｇｎｉｚａｔｉｏｎＳｔｒｕｃｔｕｒｅ,简称,ＢＯＳ）,在基组结构模型中,一个协作信息系统可分解为多个基本的子系统,第一基本的子系统用一个基组织来模型化。一个基组织内部一般定义五类主体;基组织协调控制主体,基组织维护管理主体,问题求解主体,过程性知识集成主体和公共设施主体,基组织内部的协作行为通过各类主体分工合作完成,其组织具     

An immunity-based distributed multiagent-control framework

The human immune system is a complex system of cells, molecules, tissues, and diverse organs that can provide us with primary defense against pathogenic organisms. These components are highly interactive and execute the immune response in a coordinated and specific manner. This paper presents a formal mathematical model of an artificial immune system (AIS)-based control framework. The framework aims to provide an integrated solution to control and coordinate complex distributed systems with a large number of autonomous agents such as automated warehouses, distribution centers, and automated material-handling systems. The control framework consists of a set of AIS agents working in response to the changing environment and the occurrence of tasks. The AIS agents manipulate their capabilities to derive appropriate responses to tackle different problems. A methodology describing the response-manipulation algorithm of the AIS agents and their ability to generate new capabilities is discussed in this paper. Through response manipulation and knowledge building, a self-organized and fully distributed system with agents that are able to adapt and accommodate in a dynamic environment via distributed decision making and interagent communication is achieved.     

Biotope: an integrated framework for simulating distributed multiagent computational systems

The study of distributed computational systems issues, such as heterogeneity, concurrency, control, and coordination, has yielded a number of models and architectures, which aspire to provide satisfying solutions to each of the above problems. One of the most intriguing and complex classes of distributed systems are computational ecosystems, which add an "ecological" perspective to these issues and introduce the characteristic of self-organization. Extending previous research work on self-organizing communities, we have developed Biotope, which is an agent simulation framework, where each one of its members is dynamic and self-maintaining. The system provides a highly configurable interface for modeling various environments as well as the "living" or computational entities that reside in them, while it introduces a series of tools for monitoring system evolution. Classifier systems and genetic algorithms have been employed for agent learning, while the dispersal distance theory has been adopted for agent replication. The framework has been used for the development of a characteristic demonstrator, where Biotope agents are engaged in well-known vital activities-nutrition, communication, growth, death-directed toward their own self-replication, just like in natural environments. This paper presents an analytical overview of the work conducted and concludes with a methodology for simulating distributed multiagent computational systems.     

Mobile Agent在网络管理中应用

探讨了传统的基于SNMP协议的网络管理系统的不足，分析了集中式网络管理方法的局限性和比较了各种分布式网络管理技术优缺点后，提出了采用移动代理技术(Mobile Agent)来实现网络管理并描述了一种用于设计和开发网络管理系统的移动代理技术的概要性实现框架。文章表明在网络管理中采用移动代理技术可以很好地解决目前集中式网络管理中遇到的相关问题，能有效提高网络管理的可靠性和效率。     

Algorithms for energy-driven agent placement in wireless embedded systems with memory constraints

The agent programming paradigm provides an easy to use framework for coding embedded applications in a pervasive environment. Under this model, applications are structured as mobile agents that can be flexibly installed on the available nodes of the system. Typically, such system nodes have limitations concerning battery and memory resources. The agent placement problem (APP) we consider in this paper, consists of deciding which agents should be placed at which nodes, in order to maximize the lifetime of the first node that runs out of battery. Since wireless communication has been identified in the past as a primary source of energy consumption, APP essentially involves bringing communicating agents close to each other, thus reducing communication costs. Nevertheless, this cannot always be done due to memory constraints. In fact as more and more agents are installed at the nodes finding free space at any node, let alone the desired one communication-wise, becomes hard. In this paper we tackle the problem of placing a newcomer agent in a stepwise fashion. First, enough memory space must be found or created at some node to place the agent. Second, the placement must be altered in order to make it energy efficient. We present algorithms that tackle each of the above steps separately as well as branch and bound methods for achieving both goals simultaneously. Our algorithms are centralized assuming a single entry point through which agents are injected into the system, with adequate knowledge of the system state and enough resources to run the proposed algorithms. The algorithms are evaluated under different simulated scenarios, and useful tradeoffs are identified.     

On Composite Web Services Provisioning in an Environment of Fixed and Mobile Computing Resources

We present a framework for Web services provisioning in a hybrid environment of fixed and mobile computing resources. Several obstacles still hinder the seamless provisioning of Web services in mobile environments. Examples of such obstacles are: throughput and connectivity of wireless networks, limited computing resources of mobile devices, and risks of communication channel disconnections. In the proposed framework, software agents represent users, providers of services, and providers of resources. The business logic of composite services is expressed as a process model using statecharts formalism. Among other things, the use of agents provides an infrastructure that has the ability to handle disconnections during service preparation for execution. The framework also integrates a service execution planning approach to optimally select computing resources (fixed or mobile) on top of which services will be executed.     

JavaLog: a framework-based integration of Java and Prolog for agent-oriented programming

Intelligent agent development has imposed new challenges on the necessary language support. Object-oriented languages have been proposed as an appropriate tool, although logic-oriented languages are more adequate for managing mental attitudes. Multi-paradigm languages supporting encapsulation of actions, hiding of private knowledge and flexible manipulation of knowledge are, certainly, a good alternative for programming agents. However, a unique language to support flexible and efficient development of multi-agent systems confronts with the tradeoffs imposed by expressive power, efficiency and support technology. An alternative to conciliate these tradeoffs is not to think about a single language but an incrementally compatible family of agent-oriented multi-paradigm languages. In this work we present an approach based on object-oriented framework technology for integrating object and logic paradigms in such a way that new language features can be incrementally added to the core language. This core language is based on logic modules integrated as object abstractions in the object paradigm. JavaLog is a materialization of this framework integrating Java and Prolog. This core was extended to provide multi-threading support, mobility and temporal-logic operators to Prolog. MoviLog, the mobile part of the family provides a novel mobility mechanism, reactive mobility by failure, which enables virtual Prolog databases distributed across Web sites.     

A Framework for Coordinated Control of Multiagent Systems and Its Applications

In this paper, a framework is proposed for the distributed control and coordination of multiagent systems (MASs). In the proposed framework, the control of MASs is regarded as achieving decentralized control and coordination of agents. Each agent is modeled as a coordinated hybrid agent, which is composed of an intelligent coordination layer and a hybrid control layer. The intelligent coordination layer takes the coordination input, plant input, and workspace input. In the proposed framework, we describe the coordination mechanism in a domain-independent way, i.e., as simple abstract primitives in a coordination rule base for certain dependence relationships between the activities of different agents. The intelligent coordination layer deals with the planning, coordination, decision making, and computation of the agent. The hybrid control layer of the proposed framework takes the output of the intelligent coordination layer and generates discrete and continuous control signals to control the overall process. To verify the feasibility of the proposed framework, experiments for both heterogeneous and homogeneous MASs are implemented. The proposed framework is applied to a multicrane system, a multiple robot system, and a MAS consisting of an overhead crane, a mobile robot, and a robot manipulator. It is demonstrated that the proposed framework can model the three MASs. The agents in these systems are able to cooperate and coordinate to achieve a global goal. In addition, the stability of systems modeled using the proposed framework is also analyzed.