Desynchronization is useful for scheduling nodes to perform tasks at different time. This property is desirable for resource sharing, TDMA scheduling, and collision avoiding. Inspired by robotic circular formation, we propose DWARF (Desynchronization With an ARtificial Force field), a novel technique for desynchronization in wireless networks. Each neighboring node has artificial forces to repel other nodes to perform tasks at different time phases. Nodes with closer time phases have stronger forces to repel each other in the time domain. Each node adjusts its time phase proportionally to its received forces. Once the received forces are balanced, nodes are desynchronized. We evaluate our implementation of DWARF on TOSSIM, a simulator for wireless sensor networks. The simulation results indicate that DWARF incurs significantly lower desynchronization error and scales much better than existing approaches.

Several prospective applications on vehicular networks have been defined. Most applications rely on beaconing mechanisms to broadcast the presence and updated information of a vehicle to surrounding neighbors. However, due to the broadcasting nature, no acknowledgement mechanism is provided. Therefore, vehicles do not perceive beacon collision if two or more vehicles simultaneously broadcast the beacons. Consequently, vehicles miss updated information from their neighbors. In this paper, we propose V-DESYNC, an algorithm that distributively desynchronizes vehicles to broadcast beacons at different times based on only timing information. V-DESYNC is designed to avoid the beacon collision and tolerate the highly dynamic behavior of vehicular networks. Our evaluation results indicate that V-DESYNC can significantly reduce the number of beacon collisions without decreasing the beaconing rate on vehicular networks.

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It is notoriously difficult and tedious to program wireless sensor networks (WSNs). To simplify WSN programming, we propose Sense2P, a logic macroprogramming system for abstracting, programming, and using WSNs as globally deductive databases. Unlike macroprograms in previous works, our logic macroprograms can be described declaratively and imperatively. In Sense2P, logic macroprogrammers can easily express a recursive program or query that is unsupported in existing database abstractions for WSNs. We have evaluated Sense2P analytically and experimentally. Our evaluation result indicates that Sense2P successfully realizes the logic macroprogramming concept while consuming minimal energy as well as maintaining completeness and soundness of the answers.