Novel route maintenance protocols for the Bluetooth ad hoc network with mobility

Bluetooth technology is specially designed for the wireless personal area networks to replace cable. Several challenges exist in Bluetooth scatternet formation and routing, since nodes can arrive and depart at arbitrary times. In this paper, novel route maintenance algorithms are proposed for the Bluetooth ad hoc networks, where nodes can enter or exit from the piconets time to time. Our protocols guarantee the connectivity among nodes and reconstruct the routes dynamically by considering location information of the nodes. Besides, it is proposed how to reduce the number of hops and to form the shortest route between the source and the destination due to addition of new nodes to a piconet. Performance analysis of our protocols show that they outperform in terms of end to end transmission delay, bandwidth consumption and average hop counts as compared to similar Bluetooth routing protocols that we have considered.     

Pipelining in multi-query optimization

Database systems frequently have to execute a set of related queries, which share several common subexpressions. Multi-query optimization exploits this, by finding evaluation plans that share common results. Current approaches to multi-query optimization assume that common subexpressions are materialized. Significant performance benefits can be had if common subexpressions are pipelined to their uses, without being materialized. However, plans with pipelining may not always be realizable with limited buffer space, as we show. We present a general model for schedules with pipelining, and present a necessary and sufficient condition for determining validity of a schedule under our model. We show that finding a valid schedule with minimum cost is NP-hard. We present a greedy heuristic for finding good schedules. Finally, we present a performance study that shows the benefit of our algorithms on batches of queries from the TPCD benchmark.     

A Location-Aware Routing Protocol for the Bluetooth Scatternet

Bluetooth is a most promising technology for the wireless personal area networks and its specification describes how to build a piconet. Though the construction of scatternet from the piconets is left out in the specification, some of the existing solutions discuss the scatternet formation issues and routing schemes. Routing in a scatternet, that has more number of hops and relay nodes increases the difficulties of scheduling and consumes the bandwidth and power resources and thereby impacts on the performance of the entire network. In this paper, a novel routing protocol (LARP) for the Bluetooth scatternet is proposed, which reduces the hop counts between the source and the destination and reconstructs the routes dynamically using the location information of the Bluetooth devices. Besides, a hybrid location-aware routing protocol (HLARP) is proposed to construct the shortest routes among the devices with or without having the location information and degenerate the routing schemes without having any location information. Experimental results show that our protocols are efficient enough to construct the shortest routing paths and to minimize the transmission delay, bandwidth and power consumption as compared to the other protocols that we have considered. Chih-Yung Chang received the Ph.D. degree in Computer Science and Information Engineering from National Central University, Taiwan, in 1995. He joined the faculty of the Department of Computer and Information Science at Aletheia University, Taiwan, as an Assistant Professor in 1997. He was the Chair of the Department of Computer and Information Science, Aletheia University, from August 2000 to July 2002. He is currently an Associate Professor of Department of Computer Science and Information Engineering at Tamkang University, Taiwan. Dr. Chang served as an Associate Guest Editor of Journal of Internet Technology (JIT, 2004), Journal of Mobile Multimedia (JMM, 2005), and a member of Editorial Board of Tamsui Oxford Journal of Mathematical Sciences (2001--2005). He was an Area Chair of IEEE AINA'2005, Vice Chair of IEEE WisCom 2005 and EUC 2005, Track Chair (Learning Technology in Education Track) of IEEE ITRE'2005, Program Co-Chair of MNSA'2005, Workshop Co-Chair of INA'2005, MSEAT'2003, MSEAT'2004, Publication Chair of MSEAT'2005, and the Program Committee Member of USW'2005, WASN'2005, and the 11th Mobile Computing Workshop. Dr. Chang is a member of the IEEE Computer Society, Communication Society and IEICE society. His current research interests include wireless sensor networks, mobile learning, Bluetooth radio systems, Ad Hoc wireless networks, and mobile computing. Prasan Kumar Sahoo got his Master degree in Mathematics from Utkal University, India. He did his M.Tech. degree in Computer Science from Indian Institute of Technology (IIT), Kharagpur, India and received his Ph.D in Mathematics from Utkal University, India in April, 2002. He joined in the Software Research Center, National Central University, Taiwan and currently working as an Assistant Professor, in the department of Information Management, Vanung University, Taiwan, since 2003. He was the Program Committee Member of MSEAT'2004, MSEAT'2005, WASA'2006, and IEEE AHUC'2006. His research interests include the coverage problems, modeling and performance analysis of wireless sensor network and Bluetooth technology. Shih-Chieh Lee received the B.S. degree in Computer Science and Information Engineering from Tamkang University, Taiwan, in 1997. Since 2003 he has been a Ph.D. Students in Department of Computer Science and Information Engineering, Tamkang University. His research interests are wireless sensor networks, Ad Hoc wireless networks, and mobile/wireless computing.     

Influence of SCN− moiety on CH3NH3PbI3 perovskite film properties and the performance of carbon-based hole-transport-layer-free perovskite solar cells

Journal of Materials Science: Materials in Electronics - CH3NH3PbI3 perovskite films were prepared via a hot-casting method using six different CH3NH3I, PbI2 and Pb(SCN)2 solutions. Surface...     

A Location Aware Mobility based Routing Protocol for the Bluetooth Scatternet

Bluetooth is a most promising technology designed for the wireless personal area networks for the cable replacement. In this paper, a location aware mobility based routing scheme for the Bluetooth scatternet is proposed that constructs the links dynamically. Our proposed routing protocol requires location information of the nodes and constructs the route between any source and destination and reduces the number of hops. Besides, the network routing problems are analyzed and role switch operations are proposed to mitigate the problems. Moreover, the roles switch and route optimization operations are also proposed to improve route performance. Rigorous simulation works are done to evaluate the performance of our protocol in terms of mobility speed and number of mobile nodes and to compare our results with similar Bluetooth routing protocols. It is observed that our protocol outperforms in terms of energy consumption and transmission packet overheads as compared to similar Bluetooth routing protocols.

An Efficient Channel Allocation Technique for Multiple Videos-on-Demand

There are several broadcasting protocols for video-on-demand (VOD). Most of these protocols are tailored to handle the distribution of single video for a specific range of request arrival rates. In order to distribute multiple videos, broadcasting protocols like fast broadcasting (FB), new pagoda broadcasting (NPB) and universal distribution (UD) require more channels that are proportional to the number of hot videos to be broadcast. We present here an efficient broadcasting protocol in which, channel numbers can be reduced when multiple videos are broadcast either simultaneously or asynchronously. During the low to moderate request rates, our protocol performs best as similar to other reactive protocols and saves bandwidth and requires lesser number of channels as compared to other proactive or reactive protocols.