1,721,121 research outputs found
A preemption-based scheduling algorithm for WiMAX networks
No full textSeveral scheduling techniques were designed for the base station (BS) of IEEE 802.16e wireless interoperability of microwave access networks. However, depending on the BS scheduler alone to determine the servicing order of each connection might affect the accuracy of the scheduling process because the BS does not necessarily have enough up-to-date information about the current state of the connections at the subscriber station. In this paper, we propose a preemption-based scheduling algorithm that focuses on improving the quality of service requirements of real-time service flow classes. The proposed algorithm incorporates two schedulers, one at the BS and another one at the subscriber station. We have implemented and integrated the proposed algorithm with the network simulator NS2 using the Network and Distributed Systems Laboratory wireless interoperability of microwave access module. Simulation results have shown that the proposed approach outperforms other scheduling algorithms in terms of enhancing the throughput and the average delay of real-time quality of service classes. © 2013 John Wiley and Sons, Ltd.Abu Ali N, 2009, COMPUT COMMUN, V32, P511, DOI 10.1016-j.comcom.2008.09.015; Andel TR, 2006, COMPUTER, V39, P48, DOI 10.1109-MC.2006.242; [Anonymous], 2009, 802162009 IEEE; [Anonymous], 2006, 80216E2006 IEEE; Chen J, 2006, WNS2 06, P5; Chen JF, 2005, IEEE ICC, P3422; Chu G, 2002, P INT C COMM CIRC SY, P435; Cicconetti C, 2007, IEEE T MOBILE COMPUT, V6, P26, DOI 10.1109-TMC.2007.250669; DEMERS A, 1989, COMP COMM R, V19, P1; Georgiadis L, 1997, IEEE T INFORM THEORY, V43, P1518, DOI 10.1109-18.623149; Hahne EL, 1986, P IEEE INT C COMM TO; Hawa M, 2002, P 10 IEEE INT WORKSH, P247; Madhavapeddi Shreedhar and George Varghese, 1995, ACM COMPUTER COMMUNI, V25, P231, DOI DOI 10.1145-217391.217; Moraes L, 1984, IEEE T COMMUN, V32, P583, DOI 10.1109-TCOM.1984.1096106; Pitic R, 2010, WIREL COMMUN MOB COM, V10, P912, DOI 10.1002-wcm.802; Safa H, 2007, I C COMP SYST APPLIC, P203, DOI 10.1109-AICCSA.2007.370884; Safa H, 2011, P IEEE INT C SEL TOP, P94; Sayenko A, 2008, COMPUT NETW, V52, P96, DOI 10.1016-j.comnet.2007.09.021; So-In C, 2009, P IFIP WIR DAYS C DE, P1; Tokel TB, 2010, EURASIP J WIREL COMM, DOI 10.1155-2010-5275910
An interoperability model for supporting reliability and power-efficient routing in MANETs
No full textHandheld devices in Mobile Ad hoc Networks (MANETs) use different communication technologies and are equipped with different software- hardware processing capabilities. This multi-level heterogeneity poses a serious challenge on the performance of such networks. This paper proposes an interoperability model for supporting coexistence between heterogeneous devices and power-efficient routing in a mobile environment. The model is represented through a three-layered paradigm: a communication service layer that deals with available communication capabilities; a communication capability layer that is responsible for controlling and managing the lower communication service layer; and a communication interface layer that provides the applications with a unified public interface. The paper focuses on the architecture and design of the system, and also presents simulation results to show the impact of the proposed model on the network performance. Copyright © 2009, Inderscience Publishers.[Anonymous], 1999, 80211 IEEE; Bisdikian C, 2001, IEEE COMMUN MAG, V39, P86, DOI 10.1109-35.968817; BLUETOOTH SIG, 2001, SPECIFICATION BLUETO; Broch J., 1999, INT S PAR ARCH ALG N, P370; CHAKERES I, 2003, 200318 U CAL SANT BA; Chlamtac I, 2003, AD HOC NETW, V1, P13, DOI DOI 10.1016-S1570-8705(03)00013-1; Clausen T., 2003, 3626 RFC; Crow BP, 1997, IEEE COMMUN MAG, V35, P116, DOI 10.1109-35.620533; FEENEY L, 1999, T9911 SICS; Feeney LM, 2001, MOBILE NETW APPL, V6, P239, DOI 10.1023-A:1011474616255; Gast M. S., 2002, 802 11 WIRELESS NETW; GAUTHIER P, 1996, P MOMUC 96 SEPT PRIN; Lansford J, 2001, IEEE NETWORK, V15, P20, DOI 10.1109-65.953230; Lundberg M, 2004, P 21 IEEE INSTR MEAS, V1, P91; Mahmoud Q. H., 2003, WIRELESS APPL PROGRA; MUCHOW J, 2001, J2ME 3, V101; Perkins C., 2004, AD HOC NETWORKING; Perkins C. E., 1999, Proceedings WMCSA'99. Second IEEE Workshop on Mobile Computing Systems and Applications, DOI 10.1109-MCSA.1999.749281; Safa H, 2006, P 2 IEEE INT C WIR M, P45; SAFA H, 2007, P 5 ACS IEEE INT C C, P893; SWEET C, 1999, IEEE 802 11 PERFORMA; Villasenor-Gonzalez L, 2005, IEEE COMMUN MAG, V43, P118, DOI 10.1109-MCOM.2005.1470838; Weniger K, 2004, IEEE NETWORK, V18, P6, DOI 10.1109-MNET.2004.131675444
An energy efficient Genetic Algorithm based approach for sensor-to-sink binding in multi-sink wireless sensor networks
No full textWireless sensor networks (WSNs) are ad-hoc networks in which sensors, that are designed to relay data back to sink nodes and-or Base Stations, are deployed in an area and may be configured in real time. Sensors, however, have limited energy supplies and are often left untouched after deployment, thus making battery replacement very difficult or even impossible. Therefore, energy should be efficiently conserved to extend the WSNs lifetime. One of the existing solutions is to deploy multiple sinks, more capable nodes in comparison to sensors, in the network to increase the coverage area and shorten the communication distance between sensors and sinks. However, this raises the issue concerning which sensors should bind to which sinks in order to avoid overloading particular sinks. In this paper, we devise a Genetic Algorithm based approach to solve the problem of balancing the load of sensors amongst sinks in a multi-sink WSN, while ensuring that the best routes to sinks are found for the sensors that cannot directly reach a sink. We evaluate the performance of our approach and compare it to an existing one using the network simulator NS-2 through measuring several metrics such as the variance of remaining energy among sinks, and energy consumption in sinks. The obtained results show that the proposed approach promising. © Springer Science+Business Media New York 2013.Akyildiz I. F., 2010, WIRELESS SENSOR NETW; Andel TR, 2006, COMPUTER, V39, P48, DOI 10.1109-MC.2006.242; English J, 2006, 2006 23rd Biennial Symposium on Communications, P320, DOI 10.1109-BSC.2006.1644632; Gupta G., 2003, P IEEE INT C COMM IC, V3, P1848; Hasancebi O, 2000, COMPUT STRUCT, V78, P435, DOI 10.1016-S0045-7949(00)00089-4; Kulik J, 2002, WIREL NETW, V8, P169, DOI 10.1023-A:1013715909417; Kim H, 2005, LECT NOTES COMPUT SC, V3391, P264; KIRKPATRICK S, 1983, SCIENCE, V220, P671, DOI 10.1126-science.220.4598.671; Min R., 2000, IEEE WORKSH SIGN PRO, P581; Perkins C. E., 1999, P 2 IEEE WORKSH MOB, V6, P90; Safa H., 2012, P IEEE INT IN PRESS; Safa H., 2011, 2011 Proceedings of IEEE Symposium on Wireless Technology and Applications (ISWTA 2011), DOI 10.1109-ISWTA.2011.6089389; Sinha A., 2000, P 13 INT C VLSI DES, P50; SRINIVAS M, 1994, COMPUTER, V27, P17, DOI 10.1109-2.294849; Tas N. C., 2008, P 17 IEEE INT C COMP, P1; Wang RL, 2004, NEUROCOMPUTING, V57, P463, DOI 10.1016-j.neucom.2003.12.003; Weng C.-E., 2012, COMMUNICATION, DOI [10.1007-s11277-012-0571-0, DOI 10.1007-S11277-012-0571-0]; Yi Poe W, 2008, P 14 GI ITG C MEAS M, P253; Zhu YH, 2011, MOBILE NETW APPL, V16, P58, DOI 10.1007-s11036-009-0211-41
A robust topology control solution for the sink placement problem in WSNs
No full textPlacing a certain number of sinks at appropriate locations in WSNs reduces the number of hops between a sensor and its sink resulting in less exchanged messages between nodes and consequently less energy consumption. Since finding the optimal number of the sinks to be added and their locations is an NP Hard problem, we propose in this paper, a topological level solution that uses a meta-heuristic based on Particle Swarm Optimization (PSO) to decide on the number of sinks and their locations; more specifically we use Discrete PSO (DPSO) with local search. Traffic Flow Analysis (TFA) is used to calculate the fitness function of the network defined as the maximum worst case delay. Since TFA is usually used to analyze networks with one sink, we present the extension that allows it to be used with multiple sinks. Furthermore, we formulated the problem, discretized it, and applied PSO while introducing local search to the inner workings of the algorithm. Extensive experiments were conducted to evaluate the efficiency of DPSO. DPSO was compared with Genetic Algorithm-based Sink Placement (GASP), which is considered the state-of-the-art in solving the multiple sink placement problem. In all scenarios, DPSO was 2 to 3 times faster than GASP. When compared with respect to delay, DPSO achieved less delay in most scenarios, except for few scenarios where it performed similar to GASP or a bit worst. Topologies with random as well as heavy tailed distribution were used in the experiments. Moreover, we present via simulation the substantial benefit of adding more sinks to a wireless network. © 2013 Elsevier Ltd.Anastasi G, 2009, AD HOC NETW, V7, P537, DOI 10.1016-j.adhoc.2008.06.003; [Anonymous], 2008, BOSTON U REPRESENTAT; [Anonymous], 2009, DISCO NETWORK CALCUL; Ben-Othman J, 2010, J PARALLEL DISTR COM, V70, P849, DOI 10.1016-j.jpdc.2010.02.010; Gallan N, 2008, P 14 GI ITG C MEAS M, P291; Gollan N, 2007, I S MOD ANAL SIM COM, P80; Guner A, 2008, J ARTIFICIAL EVOLUTI, V8; Kennedy J., 2001, SWARM INTELLIGENCE; Kim H, 2005, LECT NOTES COMPUT SC, V3391, P264; Le J.-Y. Boudec, 2001, LNCS; Oyman E.I., 2004, P IEEE INT C COMM JU, V6, P3663; Papadopoulos A, 2012, J NETW COMPUT APPL, V35, P1177, DOI 10.1016-j.jnca.2011.05.004; Roedig U, 2007, P 2 PERF CONTR WIR S; Safa H, 2012, P IEEE INT C COMM IE; Safa H, 2010, INT J COMMUN SYST, V23, P463, DOI 10.1002-dac.1084; Schmitt J., 2006, P 1 INT C PERF EV ME; SCHMITT JB, 2006, P PERF CONTR WIR SEN, P6; Schmitt JB, 2005, LECT NOTES COMPUT SC, V3560, P141; Turkogullari YB, 2010, AD HOC NETW, V8, P654, DOI 10.1016-j.adhoc.2010.01.005; Tyagi S, 2013, J NETW COMPUT APPL, V36, P623, DOI 10.1016-j.jnca.2012.12.001; Ye W, 2002, IEEE INFOCOM SER, P1567; Yi Poe W, 2008, P 14 GI ITG C MEAS M, P253; Yi Poe W, 2007, 36207 U KAIS, P1; Younis M, 2008, AD HOC NETW, V6, P621, DOI 10.1016-j.adhoc.2007.05.003; Zungeru AM, 2012, J NETW COMPUT APPL, V35, P1508, DOI 10.1016-j.jnca.2012.03.0040
A cache invalidation strategy for mobile networks
No full textThe diversity of services delivered over wireless channels has increased people's desire in ubiquitously accessing these services from their mobile devices. However, a ubiquitous mobile computing environment faces several challenges such as scarce bandwidth, limited energy resources, and frequent disconnection of the server and mobile devices. Caching frequently accessed data is an effective technique to improve the network performance because it reduces the network congestion, the query delay, and the power consumption. When caching is used, maintaining cache consistency becomes a major challenge since data items that are updated on the server should be also updated in the cache of the mobile devices. In this paper we propose a new cache invalidation scheme called Selective Adaptive Sorted (SAS) cache invalidation strategy that overcomes the false invalidation problem that exists in most of the invalidation strategies found in the literature. The performance of the proposed strategy is evaluated and compared with the selective cache invalidation strategy and the updated invalidation report startegy found in the literature. Results showed that a significant cost reduction can be obtained with the proposed strategy when measuring performance metrics such as delay, bandwidth, and energy. © 2009 Elsevier Ltd. All rights reserved.ARTAIL H, 2005, P IEEE INT C WIR MOB, P237; Artail H, 2008, IEEE T MOBILE COMPUT, V7, P961, DOI 10.1109-TMC.2008.18; Cai J, 1999, WIREL NETW, V5, P489, DOI 10.1023-A:1019144304789; CAO G, 2002, IEEE T COMPUT, V5, P608; Cao GH, 2003, IEEE T KNOWL DATA EN, V15, P1251; Chand N, 2007, INT J AD HOC UBIQ CO, V2, P83, DOI 10.1504-IJAHUC.2007.011606; Friedman R., 2002, P 2 ACM INT WORKSH P, P90; Huang Y., 1994, SIGMOD 94, P13; LIM S, 2007, COMPUTER COMMUNI JUN, P1854; MADHUKAR A, 2006, P 2006 ACM S APPL CO, P1122, DOI 10.1145-1141277.1141545; Perkins C., 2004, AD HOC NETWORKING; SAFA H, 2008, P ACM INT C MOB TECH, P1, DOI 10.1145-1506270.1506272; SHAO X, 2003, P INT C MACH LEARN C, P2389; Tan KL, 2001, IEEE T PARALL DISTR, V12, P789; Weniger K, 2004, IEEE NETWORK, V18, P6, DOI 10.1109-MNET.2004.1316754; Yeung MKH, 2005, IEEE T MOBILE COMPUT, V4, P68, DOI 10.1109-TMC.2005.14; Yin LZ, 2006, IEEE T MOBILE COMPUT, V5, P77; 2008, NS 2 SIMULATOR54
HAODV: A new routing protocol to support interoperability in heterogeneous MANET
No full textIn today's MANET, nodes can be equipped with one or more wireless communications interfaces that support different wireless technologies such as WIFIIEEE 802.11 and Bluetooth. Each technology implements distinct hardware and logical specifications. Current AODV routing protocol becomes inefficient when used in a network formed of heterogeneous devices. Indeed AODV in its nature search the paths between homogeneous devices and ignore the ones between heterogeneous devices. In this paper, we propose a heterogeneous AODV protocol that interoperates between WIFI and Bluetooth technologies in a single MANET. The extended algorithm takes into consideration several factors when building the routes such as network stability, traffic, conversion rate; in addition to the shortest path. © 2007 IEEE.[Anonymous], 1999, 80211 IEEE; BAJAJ L, 1997, 990027 CSD; BISDIKIAN C, 2001, IEEE COMMUNICATION M; *BLUET SIG, 2001, SPEC BLURT SYST VERS; Broch J., 1998, DYNAMIC SOURCE ROUTI; Broch J., 1999, INT S PAR ARCH ALG N, P370; CHAKERES I, 2003, 200318 U CAL SANT BA; Chlamtac I, 2003, AD HOC NETW, V1, P13, DOI DOI 10.1016-S1570-8705(03)00013-1; Clausen T., 2003, 3626 RFC; Dijkstra E., 1959, NUMER MATH, P269; Fall K., 2000, NS NOTES DOCUMENTS; Manzoni P, 2003, COMPUT NETW, V42, P23, DOI 10.1016-S1389-1286(02)00367-5; Perkins C., 2004, AD HOC NETWORKING; Perkins C. E., 1999, Proceedings WMCSA'99. Second IEEE Workshop on Mobile Computing Systems and Applications, DOI 10.1109-MCSA.1999.749281; Safa H, 2006, P 2 IEEE INT C WIR M, P45; Villasenor-Gonzalez L, 2005, IEEE COMMUN MAG, V43, P118, DOI 10.1109-MCOM.2005.1470838; XU K, 2002, P MILCOM AN CA OCT, P838; Zhong XF, 2003, PIMRC 2003: 14TH IEEE 2003 INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS PROCEEDINGS, VOLS 1-3 2003, P20175
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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