The IEEE Transactions on Mobile Computing ( TMC) has completed four years since its inception in January 2002. Since the beginning, the quality and quantity of papers submitted to TMC have both improved significantly. While these increases are desirable, the increased load has also led to an increase in the submission-to-publication time. To address this issue, I am pleased to report that TMC will begin monthly publication with this issue. With this change, it is hoped that we can continue to publish papers in a timely manner, despite the increasing number of paper submissions.

We also continue to add new members to the editorial board, in part to replace the editors who are retiring, but also to expand the editorial board to provide better coverage of topics that are of interest to TMC. I would like to express my gratitude to the following associate editors who have either completed or will complete their terms in the near future: Ramon Caceres, Erdal Cayirci, Per Gunningberg, Rajesh Gupta, Michael Huhns, Antonio Orlandi, Ram Ramjee, Asim Smailagic, and Michele Zorzi. I would also like to welcome several new associate editors who have joined the editorial board in recent months: Tarek Abdelzaher, Elizabeth M. Belding-Royer, Hesham El Gamal, Abdelsalam (Sumi) Helal, Chandra Narayanaswami, Ravi Prakash, and Krithi Ramamritham. The biographies of the new associate editors are provided below.

I conclude by expressing my sincere thanks for the efforts of the referees on whom we rely on for in depth reviews, and the editorial board members who manage the review process. My thanks also to the staff at the IEEE Computer Society, particularly Jennifer Carruth, Pilar Hawthorne, and Suzanne Werner, who help maintain the tight schedule by processing the papers expeditiously.

I invite the readers to send their input and suggestions on how to improve TMC to me or to any of the editorial staff. I hope you will continue to enjoy the articles in TMC, and support the Transactions by submitting your best research.

Nitin H. Vaidya

Editor-in-Chief

Tarek Abdelzaher received the BSc and MSc degrees in electrical and computer engineering from Ain Shams University, Cairo, Egypt, in 1990 and 1994, respectively. He received the PhD degree from the University of Michigan in 1999 in quality of service adaptation in real-time systems. He has been an assistant professor at the University of Virginia from 1999 to 2005, where he founded the Software Predictability Group. He is currently an associate professor in the Department of Computer Science, the University of Illinois at Urbana Champaign. He has authored/coauthored three book chapters and more than 60 refereed publications in leading conferences and journals in several fields including real-time computing, distributed systems, sensor networks, and control. He is an associate editor of the Journal of Real-Time Systems, the International Journal of Embedded Systems, the Ad Hoc Networks Journal, as well as editor of the ACM SIGBED Review. He was guest editor for the Journal of Computer Communications and the Journal of Real-Time Systems, and is coeditor of the IEEE Distributed Systems Online. He served on numerous technical program committees in real-time computing, networking, quality of service, distributed systems, sensor networks, multimedia, and mobile computing, among others. He also held several conference organization positions including program chair of RTAS 2004, demo chair of Mobisys 2005, poster chair of ICDCS 2003, sensor networks vice chair of RTSS 2005, and general chair of RTAS 2005. His research interests lie broadly in understanding and controlling the temporal properties of software systems in the face of increasing complexity, distribution, and degree of embedding in an external physical environment. He is a member of the IEEE and the ACM.

Elizabeth M. Belding-Royer is an associate professor in the Department of Computer Science at the University of California, Santa Barbara. Her research focuses on mobile networking, specifically ad hoc and mesh networks, multimedia, monitoring, and advanced service support. She is the founder of the Mobility Management and Networking (MOMENT) Laboratory (moment.cs.ucsb.edu) at UCSB. She is the author of numerous papers related to ad hoc networking and has served on many program committees for networking conferences. She served as the TPC Co-Chair of ACM MobiCom 2005 and IEEE SECON 2005, and is currently on the editorial board for the IEEE Transactions on Mobile Computing. She is the recipient of an NSF CAREER award, and a 2002 Technology Review 100 award, awarded to the world's top young investigators. See http://www.cs.ucsb.edu/~ebelding for further details.

Hesham El Gamal received the BS and MS degrees in electrical engineering from Cairo University, Cairo, Egypt, in 1993 and 1996, respectively, and the PhD degree in electrical and computer engineering from the University of Maryland at College Park, Maryland, in 1999. From 1993 to 1996, he served as a project manager in the Middle East Regional Office of Alcatel Telecom. From 1996 to 1999, he was a research assistant in the Department of Electrical and Computer Engineering, the University of Maryland at College Park, Maryland. From February 1999 to December 2000, he was with the Advanced Development Group, Hughes Network Systems (HNS), Germantown, Maryland, as a senior member of the technical staff. In the Fall of 1999, he served as a lecturer at the University of Maryland at College Park. In January 2001, he joined the Electrical and Computer Engineering Department at The Ohio State University where he is now an associate professor. He held visiting appointments at the University of California at Los Angeles (Fall 2002, Winter 2003) and Institut Eurecom (Summer 2003). He is a recipient of the HNS Annual Achievement Award (2000), the OSU College of Engineering Lumley Research Award (2003), the OSU Electrical Engineering Department FARMER Young Faculty Development Fund (2003-2008), and the National Science Foundation CAREER Award (2004). He holds six US patents and has eight more patent applications pending. He was an associate editor for the IEEE Transactions on Communications (2001-2005). He is a senior member of the IEEE, currently serves as an associate editor for the IEEE Transactions on Mobile Computing, and is a member for the SP4COM Technical Committee.

Abdelsalam (Sumi) Helal received the BSc and MSc degrees in computer science and automatic control from Alexandria University, Alexandria, Egypt, in 1982 and 1985, respectively, and the PhD degree in computer sciences from Purdue University, West Lafayette, Indiana, in 1991. Before joining the University of Florida, he held academic and industrial research positions at MCC at Austin, Purdue, and the University of Texas at Arlington. He is a professor at the Computer and Information Science and Engineering Department (CISE) at the University of Florida. His research interests span the areas of pervasive computing, mobile computing and networking, and internet computing. He is director of the Mobile and Pervasive Computing Laboratory at the CISE Department (www.icta.ufl.edu), and director of technology development at the NIDRR-funded Rehabilitation Engineering Research Center on Successful Aging (www.rerc.ufl.edu). He is cofounder and director of the Gator Tech Smart House (www.icta.ufl.edu/gt.htm), and is director of the Sensor Platform initiative (www.sensorplatform.org). Dr. Helal is also founder, President, and CEO of Phoneomena, Inc. (www.phoneomena.com) a company that specializes in mobile middleware products. Dr. Helal is cofounder and an editorial board member of the IEEE Pervasive Computing magazine. He is editor of the magazine's column on Standards, Tools, and Emerging Technologies. He has published more than 160 books, book chapters, and refereed journal and conference papers. He is sole or coinventor on 16 US patents and copyrights. He is a senior member of the IEEE, and a member of the ACM and the USENIX Association. More information about Dr. Helal's research and professional activities can be found at: http://www.icta.ufl.edu.

Chandra Narayanaswami received the BTech degree in electrical engineering from the Indian Institute of Technology, Bombay, and the MS and PhD degrees in computer and systems engineering from Rennselaer. He currently manages a group on technologies for client computing at IBM Research that is investigating infrastructure support and middleware, device symbiosis, new usage modes, applications and tools, efficient data access and dissemination, and novel user interfaces-mostly in the context of mobile computing. He led the multisite, multidisciplinary IBM Research effort on developing the WatchPad, a high function wrist watch computer. He has also helped develop novel concepts in mobile computing such as the Personal Mobile Hub and SoulPad. His work has benefited several IBM products. He has received 20 Invention Achievement Awards and an Outstanding Technical Achievement from IBM. He has authored several journal publications, conference papers, and book chapters. He holds approximately 40 US patents in the areas of computer graphics and pervasive computing. He was the general chair for the Seventh IEEE Symposium on Wearable Computers in 2003. He has also served on program committees for several ACM/IEEE conferences over the years. See http://www.research.ibm.com/people/c/chandras for more details.

Ravi Prakash received the BTech degree in computer science and engineering from the Indian Institute of Technology, Delhi, in 1990 and the MS and PhD degrees in computer and information science from The Ohio State University, Columbus, in 1991 and 1996, respectively. He joined the Department of Computer Science, University of Texas at Dallas in July 1997, where he is an associate professor. During 1996-1997, he was a visiting assistant professor in the Computer Science Department, University of Rochester. His areas of research are mobile computing, distributed computing, and sensor networks. He has published his results in various journals and conferences and has been involved in the organization of various IEEE and ACM conferences and workshops as technical program chair, technical program committee member, etc., including the technical vice chair for mobile computing at the IEEE International Conference on Distributed Computing Systems (ICDCS) 2002 and the technical program cochair for the ACM Workshop on Principles of Mobile Computing (POMC) 2002 and the IEEE Symposium on Reliable Distributed Systems (SRDS) 2004. He is a recipient of the US National Science Foundation CAREER grant.

Krithi Ramamritham received the PhD degree in computer science from the University of Utah and then joined the University of Massachusetts. He is currently at the Indian Institute of Technology Bombay as the Vijay and Sita Vashee Chair Professor in the Department of Computer Science and Engineering. Ramamritham's interests span the areas of real-time systems, database systems, and real-time databases systems. He is applying concepts from these areas to solve problems in embedded systems, mobile computing, e-commerce, intelligent internet, and the Web. Professor Ramamritham is a fellow of the IEEE , a fellow of the ACM, and a fellow of the Indian National Academy of Engineering.