ATOMAS A Transaction-oriented Open Multi Agent-System. Final(6)

ATOMAS:

1Introduction6

ATOMAS:

2Workplan and Project State72Workplan and Project State

In the second year, the agent system architecure developed in the rst year had to be extendedto support migration and to provide reliable agent execution. Furthermore, requirements con-cerning security issues had to be investigated and the concepts developed during the project hadto be evaluated. Therefore, four work packages had been identi ed (Section 2.1 - Section 2.4 ).In addition orphan detection for agents has been identi ed as a very important functionality tobe supported by mobile agent systems and thus an additional work package (Section 2.5) hasbeen added that concentrates on this aspect.

The following sections contain a short introduction into the work packages and the completionstate of these work packages.

2.1WP 2.1: Design and Implementation of Agent Migration

In work package 1.2, a special form of migration, called weak migration, had already been de-veloped during the rst year. This form of migration has the advantage that it can be implement-ed without changing the Java virtual machine and therefore allows to run the developed agentsystem on each architecture for which a Java virtual machine is available. Our experience in us-ing this form of migration in several student thesises proved the validity of this concept. There-fore, no further work has been invested in this topic in the second year.

2.2WP 2.2: Requirement Analysis Concerning Security

In the rst year, driven by the importance of the security aspect of mobile agent systems, wealready started this work package. Section 7 of the last years report investigates the security as-pects of Mobile Agent Systems and identi es the problem areas which has to be handled.

In Section 3 of this report, a approach to partially solve one of the most dif cult aspects of se-curity of mobile agents systems,the problem of malicious hosts, is presented. This problem con-sists in the possibility of attacks against a mobile agent by the party that maintains an agent sys-tem node, a host.

2.3WP 2.3 Recoverable Agents

An important prerequisite for the use of mobile agents in industrial environments is to providereliable and fault tolerant execution of the agents. Section 4 describes two different approachesto provide the required reliability. In the rst approach, fault-tolerant execution of agents on un-reliable systems is provided. Section 4.1 summarizes two published papers on this topic. In thesecond approach, the reliability of agents is provided by using the TUXEDO platform on Tan-dem Himalaya to build the agent system.

2.4WP 2.4 Developed Concepts and Implementation

In this work package, the developed concepts are summarized and implemented within the mo-bile agent system Mole 3.0. Next to the concepts for agent communication and agent migration