An information agent manages all or a portion of a user's information space. The electronic resources in this space are often distributed across a network and can contain tremendous quantities of data. Mobile agents provide efficient access to such resources and are a powerful tool for implementing information agents. A mobile agent is an autonomous program that can migrate from machine to machine in a heterogeneous network. By migrating to the location of a resource, the agent can access the resource efficiently even if network conditions are poor or the resource has a low-level interface. Telescript is the best-known mobile-agent system. Telescript, however, requires the programmer to learn and work with a complex object-oriented language and a complex security model. Agent Tcl, on the other hand, is a simple, flexible, and secure system that is based on the Tcl scripting language and the Safe Tcl extension. In this paper we describe the architecture of Agent Tcl and its current implementation.

Nowadays, the widespread use of wireless devices that can be connected to Internet allows users to access information from anywhere and at anytime. However, the management of Internet data services makes users of wireless devices face certain problems such as the inestability of the used media, the lack of suitability of existing services to the limited capabilities of some wireless devices (e.g., in the visualization of GUI's) and the high cost that their use implies. In this paper, we present the general features of ANTARCTICA, a system which provides users of wireless devices with a new environment to achieve their data management needs. The ANTARCTICA system is based on the use of proxies and agent technology and presents the following main features: 1) multiplicity, managing multiple data services, 2) scalability, allowing one to incorporate new services, 3) eciency, optimizing wireless communications, 4) exibility, supporting the mobility of users without restrictions, and 5) simplicity, making technical issues transparent to the users. We also report on the implementation of some services supported by ANTARCTICA and present experimental results associated to them.

Mobile agents gained immense attraction as a new programming concept for implementing distributed applications. However, up to now mobile agent programming has been mainly technology driven, with a focus on the implementation of mobile agent platforms and only small programming applications. In this work, we present an extension of the standard UML that provides language concepts for modeling mobility both in analysis and design phases. This extended version of UML is applied to the modeling of an advanced telecommunication system. Extension of the Unified Modeling Language for Mobile Agents

The mobile form of distributed computation, called mobile computation, is investigated from the viewpoints of computational model, programming language and implementation. The emphasis of this thesis compared with the related work is on analyzing existing mobile language systems from a rather implementational point of view. The contribution of this thesis is threefold. (1) We present a computational model in which dynamic transference of code, data and execution state can be represented. Several mobility mechanisms in existing mobile language systems are analyzed in the model. (2) Based on the analysis, a programming language for mobile computation is designed. The distinctive feature of the language is the facility to control the transparency of migration. (3) An implementation of the mobile programming language is presented. The language is implemented as an extension of the Java language. The implementation is so portable that the program runs on any standard Java inte...

. In this paper, we present several approaches to making the process of configuring network devices easier than is currently the case. Configuring a device requires that a number of attributes in the network and on the device be set as well as certain software components be installed. For example, a printer requires that its drivers are present on workstations that will be using it. Currently, the manager of the network has to perform all required tasks manually. We describe four approaches that start with a procedure similar to the way plug-and-play components are handled by operating systems; e.g. Microsoft Windows. We extend the plug-and-play idea to network components. Next, we describe how this basic routine can be extended to a simple distributed model. A natural extension of the distributed model is the use of CORBA to handle a distributed environment. Finally, we propose a model of plug-and-play-ness based upon mobile agents and describe its implementation. We argue that the la...

In this paper, we present DTP (Distributed Task Plan), a model to depict distributed tasks for executions by mobile agents. DTP is composed of autonomous primitives and can generate the autonomous workflow when a mobile agent executes it. DTP provides mobile agents with navigational and computational autonomies when transporting through the underlying computational network. A mobile agent plans a DTP according to current user's objectives and the knowledge about current network environments when the agent is created. If necessary a mobile agent can also replan its DTP when exceptions occur during the execution of current DTP. The replaned DTP provides the mobile agent with an alternative workflow to accomplish its owner's objectives when current DTP fails. Concentrating DTP, we discuss the autonomies of mobile agents, the autonomous methodology and the implementation mechanism of autonomous mobile agents by DTP in this paper. Keywords: distributed task plan, autonomous agents, and mob...

This paper investigates the suitability of the mobile agents approach to the problem of integrating a collection of local DBMS into a single heterogeneous large-scale distributed DBMS. The paper proposes a model of distributed transactions as a set of mobile agents and presents the relevant execution semantics. In addition, the mechanisms which are needed to guarantee the ACID properties in the considered environment are discussed. 1 Introduction The aim of this paper is to study a transactional model based on mobile agents for the development of a heterogeneous, large-scale distributed database. The distributed environment we will refer to is made up of a set of sites connected by a network, each of which has a local DBMS. The well-known advantages of the mobile agent paradigm (autonomy, local interactions, fault-tolerance improvement [1, 2, 8, 5, 6, 15]), as compared with the traditional client/server model used in the actual implementations of distributed DBMSs, led us to consider...

In the last few years, the use of portable computers and wireless networks has been widespread. The combination of both opens the door to a new technology: mobile computing. Although the wireless communication networks were designed for the transport of voice signals, their use for data transport is growing. Mobile computing allows users to access from anywhere and at anytime the data stored in repositories of their organizations (i.e. the DBs of the company in which they work) and also for available data in a global information system through Internet. Many professionals use mobile computers for their work: sales personnel, emergency services etc. in order to obtain and send information in the place where and at the moment when they actually need it. Moreover, there exist applications in this new framework where the location is an important aspect, such as those that provide information about the nearest hotels , restaurants, etc. That is, mobile computing adds a new