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Abstract: We consider a fixed, undirected, known network and a number of “mobile agents” which can traverse the network in synchronised steps. Some nodes in the network may be faulty and the agents are to find the faults and repair them. The agents could be software agents, if the underlying network represents a computer network, or robots, if the underlying network represents some potentially hazardous physical terrain. Assuming that the first agent encountering a faulty node can immediately repair it, it is easy to see that the number of steps necessary and sufficient to complete this task is , where is the number of nodes in the network, is the diameter of the network, and is the number of agents. We consider the case where one agent can repair only one faulty node. After repairing the fault, the agent dies. We show that a simple deterministic algorithm for this problem terminates within steps, where , assuming that the number of faulty nodes is at most . We also demonstrate the worst-case asymptotic optimality of this algorithm by showing a network such that for any deterministic algorithm, there is a placement of faults forcing the algorithm to work for steps. [Copyright &y& Elsevier]

In some applications, as part of a mobile agent mission, there may be the necessity of meeting a firm end-to-end deadline, although with some itinerary flexibility due to optional resources. This paper proposes an execution model based on the concept of imprecise mobile agents with timing constraints. In this paper it is considered an execution model where agents do not previously know their itineraries. The imprecise mobile agent may choose among alternative and/or optional resources. The objective is to propose and to evaluate heuristics to be used individually or in pairs by imprecise mobile agents that must accomplish a mission within a firm deadline. [ABSTRACT FROM AUTHOR]

A mobile agent is an important platform for applications for the coming ubiquitous society. Many different kinds of mobile agent platforms have been developed. However, agents from one agent platform are generally not able to migrate into another agent platform. As a solution to this problem, we propose an interoperability concept using an incarnation agent. The concept realizes logical mobility within different kinds of agent platforms. The incarnation agent extracts an agent's procedures and status, compiling them into agent platform independent format and then re-compiling them to target agent platform format, thus enabling the process to continue. The incarnation agent also has autonomy for interoperability. It manages complex migration for interoperability, so agent's procedure can be described in simple mobile model. Moreover, the incarnation agent modifies agent's procedures as applicable to facilities of target agent platform. This paper also reports an interoperability middle-ware and its examination. The middle-ware is a foundation of realizing the Incarnation Agent, and the response time and network traffic overheads by the interoperability middle-ware has been measured. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 161(4): 49–59, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20388 [ABSTRACT FROM AUTHOR]

Reliability estimation of mobile agent-based systems remains a difficult task due to the characteristics of mobile agents that include distributed and asynchronous execution, autonomy, and mobility. In this paper we present an analytical approach to estimate the reliability of mobile agent-based systems. We define the reliability of a mobile agent in terms of the processor execution time required to perform agent's tasks at each processing node and the transmission or communication time needed to transfer the agent from one processing node to another via a network to complete its mission. The failure of entire components causes failure of the agent. Simulation experiments have been conducted using stochastic Petri Nets modeling. We investigate the effect of different component reliability and availability models (processors and links) on the system throughput. The results we have obtained demonstrate the impact of different reliability and availability models on the system throughput. [ABSTRACT FROM AUTHOR]

The article reports on the development of a foundation for autonomic workflow management in a grid environment. A model for dynamic fault tolerance technique selection was developed. This can be embedded into the workflow management system for a mobile agent. Current architecture for flexible fault tolerance in the grid was then augmented in order to allow the system to optimally configure its fault tolerant systems through an awareness of the computing environment.

The Internet is a wide area distributed network emphasizing the importance of interoperability and scalability and takes a bottom-up approach by stacking local schemata. It is considered a dynamic network environment including nondeterministic and nonformatted characteristics. In this paper we propose a platform involving user adaptive agent with a mechanism to realize deliberative responses in order to carry out predictive learning of the environmental variations, not just reactive responses. Further, the present platform is applied to a network QoS control system. It is now possible to provide for graceful degradation while the trade-off point between the user and the network is found autonomously. © 2000 Scripta Technica, Electron Comm Jpn Pt 2, 83(4): 1–12, 2000 [ABSTRACT FROM AUTHOR]