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As a recently emerging distributed computing paradigm, mobile-agent technology attracts great interests because of its salient merits. However, it also brings significant security concerns, among which the security problems between a mobile agent and its platforms are of primary importance. While protecting a platform (platform or host security) can benefit from the security measures in a traditional client-server system, protecting a mobile agent (mobile-agent or code security) has not been met in traditional client-server systems and is a new area emerging with mobile-agent technology. Mobile-agent security is also believed to be the most difficult in the security areas of a mobile-agent system. Several methods are proposed to provide protection or detection mechanisms for mobile-agent security. However, many of them either lack an intuitive formal approach to formally model and analyze the system or lack security consideration for mobility-the most distinct characteristic of a mobile agent. In this paper, we extended the original elementary object system (EOS), which applies object-oriented technology to Petri nets, in several aspects because the original EOS cannot fully support the features of mobile-agent system and security modeling. Based on the extended EOS (EEOS), we developed a formal model for a generic secure mobile-agent system. This model supports not only strong mobility but also secure mobility of a mobile agent. Mutual authentication between a mobile agent and its hosting platform is accomplished in this model. Meanwhile, a security mechanism is presented for the detection of malicious platform attacks to mobile-agent code or execution flow during the mobile- agent execution. Using an intuitively graphical formal method to model, simulate, and analyze a secure mobile-agent system distinguishes this paper from other works on mobile-agent security. This paper also introduces how to translate our EEOS model to a colored Petri net (CPN) model and presents the simulation of a sample mobile-agent system model in Design/CPN Different from the mathematical or theorem-proving analysis methods used by other mobile-agent system and mobility models, we used simulation-based analysis to verify several characteristics including boundedness, liveness, concurrence, and security of the system. Compared with other analysis methods, simulation-based analysis is generally more intuitive and more widely used in industry to solve real problems. [ABSTRACT FROM AUTHOR]

The main subject of this study is to inquire whether it is possible to control transient dynamics in a multiagent dynamical system. It is a well known fact that any multiagent dynamical system follows its transient dynamics, whether its transient dynamics are temporal or not, whenever a dynamical system starts operating at any initial condition. Especially in the case of a transient state occurring frequently due to intermittent perturbations, such as from user's requests, most tasks would be processed on the system's transient dynamics. Then undoubtedly you would care to ask "Is it possible to control transient dynamics on performance and life span, or not?" So far however, for transient dynamics being rated as temporal and uncontrollable dynamics, any systematic knowledge on controlling transient dynamics for multiagent dynamical systems has not been clarified. This study has introduced a new type of agent strategy called "info-reliability." It has clarified the diversification of agent strategy as an available procedure to make the system's transient dynamics controllable on its performance and on the life span of the transient dynamics. [ABSTRACT FROM AUTHOR]