Abstract: An efficient person search method utilizing human communications characteristics such as close social network, user-dependent hot list, and high skewness in access popularity. This method makes use of hot lists in the routing process and clusters people of the same community together in the search graph, thereof creating a “small-world” effect to minimize the hop counts routing would have to go through in a Peer-to-Peer environment.

Abstract: An effective method of allowing a sensor node to estimate its own position, based only on coarse distances to its neighbors, together with an embedding mathematical tool. This method involves four major steps for each of the nodes: estimating distances to and exchange distance information with nearby nodes; performing position estimation locally; broadcasting the result; and refining its estimation. It also supports nodes joining/leaving the network and nodes with lower power. Further, because useful information for position-based routing is already embedded during the position estimation process, no extra transmission is required for efficient route determination in reporting data to a collecting node.