Jonathan Dale and David C. DeRoure
Multimedia Research Group
Department of Electronics and Computer Science
University of Southampton
With more users taking advantage of publicly accessible networks, such as corporate intranets and
the Internet, larger amounts of information is becoming electronically distributed and disseminated.
Distributed information management is an emerging technology for dealing with the problems of
managing information that is spread across networks, users and applications. We present four
categories that we consider being necessary to developing tools to undertake distributed information
To help model the dynamic and heterogeneous nature of a user's distributed information, we
advocate the use of agents and agent technologies when building distributed information
management applications. We present an agent-oriented architecture which is based around a
concept of mobile agents, since they provide a convenient abstraction for modelling distributed
Through the increasing use of large-scale networked environments, such as the Internet, users are becoming more aware of the advantages presented through the distribution of information. More electronic information is available now than ever before and this is set to grow as information networks achieve greater penetration into corporations and consumer households. However, any form of distribution brings with it a management overhead and in systems such as the World Wide Web (WWW), the burden of dealing with this lies firmly with the user.
Mobile agents are particularly suited to developing tools to deal with DIM tasks , since they offer a level of abstraction that can be modular and tailored to a particular aspect of the system; they can represent tasks, users, information, information resources, services, security management and so on. Their dynamic and extensible nature can help them deal with heterogeneous networks, data formats and communication protocols, and their mobility can help them address distribution and scalability issues.
In this paper, we present an agent-oriented architecture that supports both static and mobile agents which can support or carry out DIM tasks. Section 2 provides a description of DIM and the types of DIM agents that we are developing and in section 3 we detail the mobile agent architecture that we are using to build our exemplar DIM applications.
2. Distributed Information Management
DIM is an initiative that is being promoted by the UK Technology Foresight panel on IT and Electronics to help promote research into the management of change and evolution in distributed systems, particularly in multimedia applications . In summary, this programme of work deals with the management of multimedia information across distributed and federated systems and applications.
2.1. DIM Activities
We have identified four activities that we believe comprises DIM :
Therefore, our agents conform to the weak agent classification identified by Wooldridge and Jennings . That is, our agents posses the ability to operate independently from their user (autonomy), to communicate with the outside world (social ability), to perceive and react to changes in their environment (reactivity) and to be adaptive to new situations and to take the initiative when necessary (proactivity).
Jennings  uses the term ubiquitous computing to describe the shift from the computer and its software being just a user-directed processor to more of a delegating partnership with the user. In this way, we see DIM agents expressing and performing DIM tasks on behalf of the user to help them manage their distributed information resources; both as directed by the user, but also in the background and automatically as changes occur in the environment that either impinge upon the user's information or are of relevance to the user.
3. An Architecture for Mobile DIM Agents
The architecture that we have developed [2,3] is written in the Agent Process Interaction Language (APRIL)  and is serving as an environment in which we can test our DIM agents. Every object within the architecture is either an agent or is abstracted through an agent; this provides for a flexible and dynamic model, since new components can be added to the system by adding a new agent type.
Figure 1 shows the interaction of the core agents within the architecture:
The three mobile agents are performing DIM-related tasks; the Resource Discovery mobile agent is querying the FTP and WWW resource agent for a particular search term, the Link Assertion mobile agent is traversing the user's document set from a given root hypermedia link and determining which links are valid or invalid, and the Link Update mobile agent is updating links with a user's FTP and WWW documents that have changed recently.
In this paper we have highlighted the need for and the characteristics of Distributed Information Management. We have developed and are currently experimenting with an architecture that supports both static and mobile agents to support user-related DIM tasks. The abstraction that this architecture affords allows agents to be dynamic, modular and flexible in nature, which allows then to react and be proactive in how they interact with their environment.