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All analytical and simulation research on ad~hoc wireless networks must necessarily model radio propagation using simplifying assumptions. We provide a comprehensive review of six assumptions that are still part of many ad hoc network simulation studies, despite increasing awareness of the need to represent more realistic features, including hills,(More)
Mobile-agent systems must address three security issues: protecting an individual machine, protecting a group of machines, and protecting an agent. In this chapter, we discuss these three issues in the context of D'Agents, a mobile-agent system whose agents can be written in Tcl, Java and Scheme. (D'Agents was formerly known as Agent Tcl.) First we discuss(More)
Most comparisons of wireless ad hoc routing algorithms involve simulated or <i>indoor</i> trial runs, or outdoor runs with only a small number of nodes, potentially leading to an incorrect picture of algorithm performance. In this paper, we report on an outdoor comparison of four different routing algorithms, APRL, AODV, ODMRP, and STARA, running on top of(More)
A mobile agent is an executing program that can migrate during execution from machine to machine in a heterogeneous network. On each machine, the agent i n teracts with stationary service agents and other resources to accomplish its task. Mobile agents are particularly attractive in distributed information-retrieval applications. By moving to the location(More)
D'Agents is a general-purpose mobile-agent system that has been used in several information-retrieval applications. In this paper, we first examine one such application, operational support for military field personnel, where D'Agents greatly simplifies the task of providing efficient, application-specific access to remote information resources. After(More)
Reproducing the effects of large-scale worm attacks in a laboratory setup in a realistic and reproducible manner is an important issue for the development of worm detection and defense systems. In this paper, we describe a worm simulation model we are developing to accurately model the large-scale spread dynamics of a worm and many aspects of its detailed(More)
Computer simulation is the most common approach to studying wireless ad-hoc routing algorithms. The results, however, are only as good as the models the simulation uses. One should not underestimate the importance of <i>validation</i>, as inaccurate models can lead to wrong conclusions. In this paper, we use direct-execution simulation to validate radio(More)