This book constitutes the refereed proceedings of the 4th Annual International Conference on Wireless Algorithms, Systems, and Applications, WASA 2009, held in Boston, MA, USA, in August 2009. The 36 revised full papers presented together with 15 invited papers and 7 workshop papers were carefully reviewed and selected from numerous submissions. Providing a forum for researchers and practitioners worldwide, the papers address current research and development efforts of various issues in the area of algorithms, systems and applications for current and next generation infrastructure and wireless networks. They are divided in topical sections on applications, experimentation, power management; coverage, detection, and topology control; routing, querying, and data collection; localization, security, and services; scheduling and resource management; and online social networks, applications, and systems.

Applications, Experimentation, Power Management.- Long-Term Animal Observation by Wireless Sensor Networks with Sound Recognition.- Experimental Study on Mobile RFID Performance.- Experimental Study on Secure Data Collection in Vehicular Sensor Networks.- Experimental Study of Independent and Dominating Sets in Wireless Sensor Networks Using Graph Coloring Algorithms.- A Comparison of Block-Based and Clip-Based Cooperative Caching Techniques for Streaming Media in Wireless Home Networks.- Dynamic Power Management for Sensor Node in WSN Using Average Reward MDP.- Energy Consumption of Fair-Access in Sensor Networks with Linear and Selected Grid Topologies.- Lookahead Expansion Algorithm for Minimum Power Multicasting in Wireless Ad Hoc Networks.- RE2-CD: Robust and Energy Efficient Cut Detection in Wireless Sensor Networks.- Coverage, Detection, and Topology Control.- Energy-Efficient Composite Event Detection in Wireless Sensor Networks.- ?-Net Approach to Sensor k-Coverage.- Biologically-Inspired Target Recognition in Radar Sensor Networks.- Stochastic k-Coverage in Wireless Sensor Networks.- Herd-Based Target Tracking Protocol in Wireless Sensor Networks.- Minimum Interference Planar Geometric Topology in Wireless Sensor Networks.- Topology Inference in Wireless Mesh Networks.- Maximum Independent Set of Links under Physical Interference Model.- Routing, Querying, and Data Collection.- CSR: Constrained Selfish Routing in Ad-Hoc Networks.- Multicast Extensions to the Location-Prediction Based Routing Protocol for Mobile Ad Hoc Networks.- AGSMR: Adaptive Geo-Source Multicast Routing for Wireless Sensor Networks.- On the Capacity of Hybrid Wireless Networks with Opportunistic Routing.- NQAR: Network Quality Aware Routing in Wireless Sensor Networks.- A Network Coding Approach to Reliable Broadcast in Wireless Mesh Networks.- Workload-Driven Compressed Skycube Queries in Wireless Applications.- Routing-Aware Query Optimization for Conserving Energy in Wireless Sensor Networks.- In-Network Historical Data Storage and Query Processing Based on Distributed Indexing Techniques in Wireless Sensor Networks.- Throughput Potential of Overlay Cognitive Wireless Mesh Networks.- Data Collection with Multiple Sinks in Wireless Sensor Networks.- Communication in Naturally Mobile Sensor Networks.- Void Avoidance in Three-Dimensional Mobile Underwater Sensor Networks.- Localization, Security, and Services.- Distributed Range-Free Localization Algorithm Based on Self-Organizing Maps.- Location Discovery in SpeckNets Using Relative Direction Information.- Providing Source-Location Privacy in Wireless Sensor Networks.- Fully Decentralized, Collaborative Multilateration Primitives for Uniquely Localizing WSNs.- Relative Span Weighted Localization of Uncooperative Nodes in Wireless Networks.- A Consistency-Based Secure Localization Scheme against Wormhole Attacks in WSNs.- Can You See Me? The Use of a Binary Visibility Metric in Distance Bounding.- A Secure Framework for Location Verification in Pervasive Computing.- to Mobile Trajectory Based Services: A New Direction in Mobile Location Based Services.- Spectrally Efficient Frequency Hopping System Design under Hostile Jamming.- A QoS Framework with Traffic Request in Wireless Mesh Network.- Scheduling and Resource Management.- An Approximation Algorithm for Conflict-Aware Many-to-One Data Aggregation Scheduling in Wireless Sensor Networks.- On Approximation Algorithms for Interference-Aware Broadcast Scheduling in 2D and 3D Wireless Sensor Networks.- Dynamic Scheduling of Pigeons for Delay Constrained Applications.- Energy Efficient DNA-Based Scheduling Scheme for Wireless Sensor Networks.- Minimum-Latency Schedulings for Group Communications in Multi-channel Multihop Wireless Networks.- Traffic-Aware Channel Assignment in Wireless Sensor Networks.- Sniffer Channel Selection for Monitoring Wireless LANs.- Uplink Resource Management Design in Multi-access Wireless Networks.- Throughput Measurement-Based Access Point Selection for Multi-rate Wireless LANs.- Online Social Networks, Applications, and Systems.- Latency-Bounded Minimum Influential Node Selection in Social Networks.- Design and Implementation of Davis Social Links OSN Kernel.- Information Extraction as Link Prediction: Using Curated Citation Networks to Improve Gene Detection.- Social Network Privacy via Evolving Access Control.- Utopia Providing Trusted Social Network Relationships within an Un-trusted Environment.- Discovery and Protection of Sensitive Linkage Information for Online Social Networks Services.- Social-Stratification Probabilistic Routing Algorithm in Delay-Tolerant Network.