1. CS Dept, City Univ.1 Research Issues in Wireless Sensor Networks Prof. Xiaohua Jia Dept. of Computer Science City University of Hong Kong

2. CS Dept, City Univ.2 Characteristics of Sensor Networks Low power and limited energy supply Simple CPU (low speed, small memory) Low network speed, unreliable data link, small transmission range Large deployment and dynamic replacement No infrastructure and self & dynamic organization

3. CS Dept, City Univ.3 Layered Structure of Sensor Networks Hardware / MAC layer OS / Network Localization Database Queries Applications Time SynchTopology Cont’l Security Data AggregationRouting

4. CS Dept, City Univ.4 Localization / Time Synchronization Localization of tagged and untagged objects Finding locations of sensors without GPS One-hop or multi-hop time synchronization (important for scheduling of sensor nodes)

5. CS Dept, City Univ.5 Topology Control Adjust transmission power of nodes or determine logical neighbors of nodes. Achieving desirable connectivity / reducing interferences / increasing throughput QoS topology control Dynamic, distributed (localized), and efficient.

6. CS Dept, City Univ.6 Placement and Coverage Issues Placement of sensor nodes for good coverage or network connectivity. Placement of data-sinks for efficient data collection or network throughput. Network connectivity (or area coverage) and node density. Scheduling of nodes sleep / active for energy saving under desirable area coverage.

7. CS Dept, City Univ.7 Security of Sensor Networks Light-weight cryptographic primitives Light-weight security protocols for key distribution / key management / authentication Intrusion detection / intrusion tolerance Secured routing (lack of security infrastructure)

8. CS Dept, City Univ.8 Routing & Data Aggregation Data centric routing (data push / pull / hybrid) Backbone computation / clustering Geographic routing (GPSR, etc) QoS routing Energy efficiency & real-time issues Broadcasting / multicasting / anycasting Data aggregation & query optimizations

9. CS Dept, City Univ.9 Data Query & Data Processing Database systems for sensor networks Application data processing / signal processing / pattern recognition Location sensitive database / spatial database

10. CS Dept, City Univ.10 Applications of Sensor Networks Environment monitoring Agriculture Manufacturing industries Medicine Disaster warning / prevention / relief operations Military applications

11. CS Dept, City Univ.11 Concluding Remarks Strategic Research Directions of Sensor Networks: Special-purposed hardware design (application tailored, low cost). Security issues in sensor networks. Sensor network applications.