Divine T. Ndumu

Zeus: A toolkit for building distributed multiagent systems

The multiagent systems approach of knowledge- level cooperation between autonomous agents promises significant benefits to distributed systems engineering, such as enhanced interoperability, scalability, and reconfigurability. However, thus far, because of the innate difficulty of constructing multiagent systems, this promise has been largely unrealized. Hence there is an emerging desire among agent developers to move away from developing point solutions to point problems in favor of developing methodologies and toolkits for building distributed multiagent systems. This philosophy led to the development of the ZEUS Agent Building Toolkit, which facilitates the rapid development of collaborative agent applications through the provision of a library of agent- level components and an environment to support the agent-building process. The ZEUS toolkit is a synthesis of established agent technologies with some novel solutions to provide an integrated collaborative agent-building environment.

A perspective on software agents research

This paper sets out, ambitiously, to present a brief reappraisal of software agents research. Evidently, software agent technology has promised much. However, some five years after the word ‘agent’ came into vogue in the popular computing press, it is perhaps time the efforts in this fledgling area are thoroughly evaluated with a view to refocusing future efforts. We do not pretend to have done this in this paper—but we hope we have sown the first seeds towards a thorough first five-year report on the software agents area. The paper contains some strong views not necessarily widely accepted by the agent community.

An Introduction to Agent Technology

Intelligent agent technology is a rapidly developing area of research. However, in reality, there is a truly heterogeneous body of work being carried out under the ‘agent’ banner. In this paper, software agent technology is introduced by briefly overviewing the various agent types currently under investigation by researchers.

The Stability, Scalability and Performance of Multi-agent Systems

Much has been published on the functional properties of multi-agent systems (MASs) including their co-ordination rationality and knowledge modelling. However, an important research area which has so far received only scant attention covers the non-functional properties of MASs which include performance, scalability and stability issues — clearly thes become increasingly important as the MAS field matures, and as more practical MASs become operational. An understanding of how to evaluate and assess such non-functional properties, and hence how to improve on them by altering the underlying MAS design, is gradually emerging as a pressing concern. This paper presents preliminary work to address such concerns; particularly, it investigates the performance and scalability of a multi-agent model we have developed.Firstly, this paper defines performance, scalability and stability within the context of multi-agent applications. Following, we describe a multi-agent model that we later use to illustrate our first attempts at evolving a procedure for analysing such non-functional properties of MASs. Next, we report on our initial attempts to investigate the performance and scalability of the multi-agent model. Finally, the significance of these results in particular and of such investigations in general is discussed.

ZEUS: a toolkit and approach for building distributed multi-agent systems

The innate difficulty of constructing multi-agent systems has motivated agent developers to move away from developing point solutions to point problems in favour of developing methodologies and toolkits for building distributed multi-agent systems. This philosophy led to the development of the ZEUS Agent Building Toolkit, which facilitates the rapid development of collaborative agent applications through the provision of a library of agent-level components and an environment to support the agent building process. The ZEUS toolkit is a synthesis of established agent technologies with some novel solutions to provide an integrated collaborative agent building environment.

The ZEUS Agent Building Tool-kit

There is an emerging desire among agent researchers to move away from developing point solutions to point problems in favour of developing methodologies and tool-kits for building distributed multi-agent systems. This philosophy has led to the development of the ZEUS agent building tool-kit, which facilitates the engineering of collaborative agent applications through the provision of a library of agent-level components and an environment to support the agent building process. The ZEUS tool-kit is a synthesis of established agent technologies with some novel solutions that provide an integrated environment for rapid software engineering of collaborative agent applications.

Visualising and debugging distributed multi-agent systems

Visualising the behaviour of systems with distributed data, control and process is a notoriously difficult task. Each component in the distributed system has only a local view of the whole set-up, and the onus is on the user to integrate, into a coherent whole, the large amounts of limited information they provide. In this paper, we describe an architecture and an implemented system for visualising and controlling distributed multi-agent applications. The system comprises a suite of tools, with each tool providing a different perspective of the application being visualised. Each tool interrogates the components of the distributed application, collates the returned information and presents this information to users in an appropriate manner. This in essence shifts the burden of inference from the user to the visualiser. Our visualiser has been evaluated on four distributed multi-agent systems: a travel management application, a telecommunications network management application, a business process management demonstrator, and an electronic commerce application. Lastly, we briefly show how the suite of tools can be used together for debugging multi-agent applications an approach we refer to as debugging via corroboration.

Towards Desktop Personal Travel Agents

The growth of the World Wide Web has invested personal computer users with direct access to a wealth of information sources and services — for example, one can now check stock market share prices, book flight tickets or even do grocery shopping over the Internet. However, while the Internet enables direct access to various information sources and services, effectively integrating these services to provide a total solution to a complex task, such as arranging a transatlantic trip itinerary, remains a challenging task that requires significant human intervention. This paper discusses some of the challenges involved in providing computer-based integrated personalised travel services through a medium such as the Internet. Further, a software agent solution to this problem is presented, and an agent-based travel assistant demonstrator described, which was developed using the ZEUS collaborative agent building tool-kit.

Co-operating mobile agents for distributed parallel processing

1.1 The Team Agent Approach This paper describes a novel approach to dynamic distributed parallel processing using a mobile agent-based infrastructure. Our goal is to extend the concept of the Parallel Virtual Machine architecture [8] by using a combination of collaborative and mobile software agents to enable automatic and dynamic configuration of distributed processes. The remainder of this paper describes a mobile agent based DVM that involves several agent roles, with different functions and skills. Our approach to distributed processing is regulated by a twotier management system. At the strategic level, an anchored centralised agent is responsible for managing user interaction and determining how tasks are to be distributed. Whilst the mobile agents who deliver code to remote machines, manage local processing at an operational level. We therefore developed specialised mobile agents, each performing particular roles, which co-operate as a team to achieve user defined goals. The resulting system provides users with a much simpler means of utilising the power of distributed parallel computing. As these agents behave co-operatively as a team our system is called MATS: the Mobile Agent Team system. One of the design objectives of MATS was to minimise the code that would need to be moved about the network. This was achieved by localising the most complex functionality in an anchored (non-mobile) agent, which can then communicate with the simpler specialised mobile agents through a message passing mechanism. In effect, this is a marriage of the autonomous and social features of ‘collaborative’ agents with the facilities offered by mobile agent technology.

Visualization and debugging of distributed multiagent systems

Visualizing the behavior of systems with distributed data, control, and process is a notoriously difficult task. Each component in the distributed system has only a local view of the whole setup, and the onus is on the user to integrate, into a coherent whole, the large amounts of limited information they provide. In this article, we describe an architecture and an implemented system for visualizing and controlling distributed multiagent applications. The system comprises a suite of tools, with each tool providing a different perspective of the application being visualized . Each tool interrogates the components of the distributed application, collates the returned information, and presents this information to users in an appropriate manner. This in essence, shifts the burden ofinference from the user to the visualizer. Our visualizer has been evaluated on four distributed multiagent systems: a travel management application, a telecommunications network management application, a business process managemen...