The advances in sensor design have decreased the size, weight, and cost of sensorsby orders of magnitude, yet with the increase of higher spatial and temporal reso-lution and accuracy. With the fast progress of sensors design and communicationstechnique, sensor networks have also been quickly evolving in both research andpractical domains in the last decade. More and more sensor networks have been de-ployed in real-world to gather information for our daily life. Applications of sensornetworks can be found in battlefield surveillance, environmental monitoring, bio-logical detection, smart spaces, industrial diagnostics, etc. Although the techniqueof sensor networks has a very promising future, many challenges are still deservinglots of research efforts for its successful applications