We describe the use of the mobile agent paradigm to design an improved infrastructure for data integration in distributed sensor network (DSN). We use the acronym MADSN to denote the proposed mobileagent -based DSN. Instead of moving data to processing elements for data integration, as is typical of a client/server paradigm, MADSN moves the processing code to the data locations. This saves network bandwidth and provides an effective means for overcoming network latency, since large data transfers are avoided. Our major contributions are the use of mobile agent in DSN for distributed data integration and the evaluation of performance between DSN and MADSN approaches. We develop an enhanced multiresolution integration (MRI) algorithm where multiresolution analysis is applied at local node before accumulating the overlap function by mobile agent. Compared to the MRI implementation in DSN, the enhanced integration algorithm saves up to 90% of the data transfer time. We develop objective functions to evaluation the performance between DSN and MADSN approaches. For a given set of network parameters, we analyze the conditions under which MADSN performs better than DSN and determine the condition under which MADSN reaches its optimum performance level.

The global usage and continuing exponential growth of the World-Wide-Web poses a host of challenges to the research community. In particular, thereis an urgent need to understand and manage the dynamics of the Web, in order to develop new techniques which will make the Web tractable. We provide an overview of recent statistics relating to the size of the Web graph and its growth. We then briefly review some of the key areas relating to Webdynamics with reference to the recent literature. Finally, we summarise the talks given in a recent workshop devoted to Webdynamics which was held in the beginning of January 2001 at the University of London. Keywords. Web dynamics, Web graph, information retrieval, collaborative filtering, Web navigation,Website design, data-intensive Web applications, workflow management, e-commerce,mobile computation.

Abstract — In sensor networks, collaborative processing between multiple sensor nodes is essential in order to complement for each other’s sensing capability, tolerate faults, and provide reliable information. The client/server-based paradigm is typical for distributed processing. However, it is not the most efficient in the context of sensor networks. In this paper, we present a mobileagent-based paradigm to carry out collaborative processing, where instead of each sensor node sending local information to a processing center, as is typical in the client/server-based computing, the processing code is moved to the sensor nodes through mobile agents. This approach has great potential in providing energy-efficient and scalable collaborative processing with low latency. We design two metrics (execution time and energy consumption) and use simulation tools to quantitatively measure the performance of different computing models in collaborative processing. 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 result, we develop a cluster-based hybrid computing paradigm to combine the advantages of both paradigms. We analyze two different scenarios in hybrid computing and simulation results show that there is always one scenario that performs better than either the client/server- or mobile-agent-based paradigm.

Abstract. Web Services integration using languages such as BPEL is to be applied not only on the Internet but also in pervasive networks using wireless mobile devices. However, in such a network it is necessary to deal with constraints in resources, typically the relative narrowness and instability of network connections. Our study adopts the mobile agent technology in response to this problem and presents a mobile agent system for Web Services integration. In our system, the physical behaviors of mobile agents, including migration and cloning, are separated from the integration logic and are described as simple rules added to the BPEL integration process description. This makes it possible to add or change physical behaviors according to the environmental conditions without modification of the BPEL description. 1

Abstract. Adapting a graphical user interface (GUI) to a variety of resources with different capabilities is one of the most interesting questions of today’s mobile computation. The GUI constructed for one application should be usable on different interactive devices, e.g. WebTV terminals, WAP phones or Java-enabled devices. In this paper, we discuss existing solutions and present a solution based on mobile agents. Mobile agents construct their GUI using third-party eXtensible User interface Language (XUL), jXUL middleware and XSL transformations. Mobile agents move to host computers and then build their GUI, or act as a proxy to devices without sufficient processing capabilities (e.g., WAP devices). The result is an adaptable GUI platform that can be run on multiple devices without modifications, supporting different resources and architectures. We show the application of this approach by implementing a mobile currency converter and survey. 1

The recent change of emphasis from high performance parallel computing to high performance parallel/distributed computing has called for new techniques in distributed problem solving. Mobile agent, as a new computing paradigm, breaks the barrier of traditional client/server model and provides a more efficient solution to distributed computing. In the mobile-agent-based paradigm, data stay at the local site, while the execution code is moved to the data sites. In this paper, we describe the deployment of mobile agent in Distributed Sensor Networks (DSNs). Mobile agent is used to integrate pre-processed data located at local sensor nodes. We take target classification as an example to illustrate how mobile-agent-based DSN (MADSN) supports high performance distributed integration.

One of the most important problems studied in any sensor network is data fusion. Client/server paradigm has been a commonly used computing model in traditional distributed sensor networks (DSNs). However, the deployment of wireless sensor networks (WSNs) and its ad hoc nature have brought new challenges to the fusion task. For example, the advances in sensor technology allow better, cheaper, and smaller sensors to be used, which results in a much larger number of sensors deployed. On the other hand, sensors communicate through wireless networks where the network bandwidth is much lower than for wired communication. In this paper, we describe the usage of mobile agent for data fusion in WSNs. In this computing model, data stay at the local site, while the fusion process (code) is moved to the data sites. By transmitting the computation engine instead of data, network bandwidth requirement is largely reduced and the performance of the fusion process is more stable. One of the key problems discussed in this mobile-agentbased WSN (MAWSN) is how to plan the itinerary (or route) for a mobile agent in order to achieve progressive fusion accuracy. This paper presents a method to develop an optimal itinerary for mobile agent to fulfill the integration task while consuming minimum amount of resources, including time and power.

The possibility of accessing and/or receiving local or remote data anywhere and at anytime constitutes an important advantage in many business environments. However, when working with mobile devices, users face many problems, such as: (1) devise exposure problems – mobile devices are more vulnerable and fragile than stationary devices, because they can be easily stolen, lost or damaged, (2) media problems – wireless communications are often unstable, asymmetric and expensive, and (3) availability problems – mobile devices stay disconnected for long periods of time. To alleviate these problems, we present a service, Data Lockers, which offers to its users first, the possibility of keeping their data in a secure and safe space in a proxy, thus alleviating the device exposure problem. Next, data stored in a data locker are available even when the mobile device is disconnected, thus providing a solution to the availability problem. Finally, specific tasks are carried out at the fixed network on behalf of the mobile user, in this way relieving the media problem. The architecture of the Locker Rental Service is based on mobile agents. These agents, and the locker, stay always close to the location of the user, traveling to meet the user wherever the user moves, therefore, allowing users to use anywhere-anytime, ubiquitous persistent storage space located at the fixed network.

The integration of data mining techniques with multi agent systems to assist in dealing with information overload has received some attention during the last years. Agent Academy, a platform for training agents, introduces a whole new perspective on the improvement of agent intelligence. Data mining techniques are used in order to extract useful patterns on real high-risk and time-efficient applications, and to provide the platform with rules, decisions and classes on test case data. These metadata are embedded into agents in order to improve their existing intelligence. This paper describes the Agent Academy platform, and focuses on the issues and challenges its development has revealed through the prism of data mining. 1.

Mobile agents provide a new abstraction for deploying functionality over the existing internet infrastructure. During the last two years, we have been working on a project that tries to overcome some of the limitations found in terms of programmability and usability of the mobile agent paradigm in real applications. In the M&M framework there are no agent platforms. Instead applications become agent-enabled by using simple JavaBeans components. In this paper we present an architecture that allows currently available web servers to become capable of sending and receiving agents in an easy way. By using this approach, existing web infrastructure can be maintained, while gaining a whole new potential by being able to make use of agent technology. Our approach involves wrapping the components inside a Java servlet that can be included in any web server supporting the Servlet Specification. This servlet enables the servers to receive and send agents that can query local information, and also enables the agents to behave as servlets themselves.