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

2. 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.

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

4. 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

5. 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

6. Process

7. Results 50 40 30 20 10 50 40 30 2020 1010 5 Percent 10 20 30 40 50 40 30 20 10 Percent