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In this paper, we survey recent advances in mobility modeling for mobile ad hoc network research. The advances include some new mobility models and analysis of older mobility models. First we classify mobility models into three categories according to the degree of randomness. We introduce newly proposed mobility models in each of these categories. Next we discuss analysis for existing mobility models. We describe the analysis work in three parts. The first part is the statistical properties of the most widely used Random Waypoint Model. The second part describes the mobility metrics that aim to capture the characteristics of different mobility patterns. The last part is the impact of mobility models on the performance of protocols. We also describe some possible future work.

This paper describes an application of genetic algorithm to the traveling salesman problem. New knowledge based multiple inversion operator and a neighborhood swapping operator are proposed. Experimental results on different benchmark data sets have been found to provide superior results as compared to some other existing methods. Keywords: knowledge based multiple inversion, order crossover, knowledge based neighborhood swapping.

Coordinated checkpointing has low stable storage requirements and simplifies the recovery process by reserving a set of consistent global checkpoints. Unfortunately, most algorithms that were proposed either incurred a high communication overhead or blocked all processes. Then, a coordinated algorithm was presented which was nonblocking and which forced only a subset of all processes to participate in a checkpointing event. This algorithm was shown to create inconsistencies in some situations and new algorithms to take consistent checkpoints were proposed. However, we found that these algorithms can still result in inconsistencies when typical behavior in a distributed environment is considered, such as multiple forced checkpoints and multiple concurrent checkpoint initiations. In this paper we identify the inconsistencies that can occur and present an efficient nonblocking algorithm that collects consistent global checkpoints and avoids some of the pitfalls in distributed nonblocking checkpointing.

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