Wireless Algorithms, Systems, and Applications: 4th International Conference, WASA 2009, Boston, MA, USA, August 16-18 (Repost)

Advances in wireless communication and computing technologies have prolif- ated ubiquitous infrastructure and ad hoc wireless networks,enabling a wide - riety of applications ranging from environment monitoring to health care, from critical infrastructure protection to wireless security, to name just a few. The complexity and rami?cations of the ever-growing number of mobile users and thevarietyofservicesintensifytheinterestindevelopingfundamentalprinciples, novel algorithms, rigorous and repeatable design methodologies, and systematic evaluation frameworks for the next generation of wireless networks. The annual International Conference on Wireless Algorithms, Systems, and Applications (WASA) provides a forum for researchers and practitioners wor- wide to exchange ideas, share new ?ndings, and discuss challenging issues for the currentandnext-generationwirelessnetworks.PastWASA conferenceswere held in Xian (2006), Chicago (2007), and Dallas (2008). WASA 2009,the 4th WASA conference, took place at the Hyatt Regency- tel indowntownBoston,MA, USA, during August 16-18,2009.Eachsubmission wasreviewed by at least three ProgramCommittee members, who in some cases wereassistedbyexternalreferees.Following a rigorousreviewprocess,35 papers were selected for presentations at the conference. The best paper awards were given to Donghua Deng and Qun Li for “Communication in Naturally Mobile Sensor Networks”and to Yanxiao Zhao,Min Song, Jun Wang,and Eun Parkfor “ThroughputMeasurement-BasedAccessPointSelectionforMulti-rateWireless LANs.” Fifteen invited presentations are also included in this volume. Recognizing the rapid development and practical importance of online social networks, WASA 2009 o?ered a special workshop on online “Social Networks, Applications, and Systems.” The workshop consisted of seven papers selected by the Program Committee of the workshop, chaired by Guanling Chen and Wei Ding.