Query Optimization in Sensor Networks Mark Rossman Iris Bass Supervised by: Dr. Fatma Milli

Wireless Sensors Networks Definition: A sensor network consists of many spatially distributed sensors, which are used to monitor or detect phenomena at different locations, such as temperature changes or pollutant levels. How Sensor Networks are used: –Time Critical Projects Situations where timeliness and accuracy is more important. Collect lots of the data immediately because sensors are not needed later. –Monitoring Long Term Projects (our focus) Get an accurate global model of the environment. Collecting data throughout a lengthy period of time.

Issues Sensors –Power –Multiple sensors coordinating communication –Changes in the environment Phenomena / Environmental Monitoring –Accuracy –Redundancy Space-wise Time-wise

Lengthening The Life of a Network Rotating which nodes are active Knowledge about space redundancy –Local information –Local Strategies Knowledge about time redundancy –Get accurate data –Maximize the life of the network

Utility Based Optimization Terms –Usefulness: Potential Contribution of the node to the query. –Utility: Cost effectiveness of interrogating the node, Usefulness/cost. –Usability: Ability of the node to contribute, Utility * Processing time remaining

Process

Results Percent Percent