تشخيص رخداد با تحمل پذيري خرابي در شبكه هاي حسگر بي سيم

چكيده انگليسي :

113 Fault Tolerant Event Detection in Wireless Sensor Networks Hosein Feizresan h feizresan@ec iut ac ir Jul 12 2011 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Dr Hossein Saidi hsaidi@cc iut ac irAbstractWireless sensor networks WSNs have provided a very attractive and fast growing research fields that havebeen receiving significant attention in recent years These networks are applied extensively in military medicine industry and home applications One application involves event detection in differentenvironments where we want to know whether an event has occurred or not Generally event can be achange in environment parameters such as temperature pressure humidity etc These networks are prone tofailure and defects as a result of having limited source of energy using cheap and low quality software orhardware equipments exposing to harsh and hazardous environments being compromised by maliciousattacks and faulty nodes Therefore fault tolerance has been a challenge for event detection researches inwireless sensor networks Faults may occur due to several reasons Fault can be referred to a simpletemporarily failure of a node due to distributing process or to a node compromised by enemy and it smaliciously behavior Since the failure probabilities of the network elements which are in interaction withenvironment are more than other elements of the network the sensing unit of sensor nodes andcommunication links are investigated more often Two types of faults are considered in this thesis symmetric faults and asymmetric or byzantine faults Insymmetric faults sensor nodes only sense the phenomena incorrectly while the other parts of the node suchas processor memory radio transceiver and etc work properly and behave quite similar to the other nonfaultynodes in terms of the rest of features and functions In byzantine faults a nonfaulty node could becompromised by an adversary which tend to disturb network functionality Byzantine node transmitsconflicting results or data to other nodes intentionally The main focus of this thesis is those symmetric faults Based on coverage range events are divided into pervasive and non pervasive categories At the eventoccurrence instance all nodes are inside of event region under pervasive event assumption in contrast somenodes are out of event region under non pervasive event assumption In detection algorithms which assumenon pervasive events boundary nodes have serious problems in making correct decision In this thesis onlypervasive events are considered Symmetric fault tolerant event detection algorithms need to consider theminimum data transmission usage due to restricted sources of energy and having the low error rate in eventdetection This thesis will propose a symmetric fault tolerant event detection algorithm which takes two importantcriteria into account the minimum energy usage and the maximum correct detection To be able to comparethis algorithm with the other ones five intermediate event detection algorithms are presented Theseintermediate algorithms are derived from current proposed researches in this area The performance of thefinal proposed algorithm will be evaluated both by mathematical analysis and by using simulation tools Thesimulations are carried out in OPNET software tool The simulation results show that the proposed algorithmhas superior performance in comparison to the other algorithms in reducing the error in correct detection Key Words Wireless sensor network Event detection Pervasive and nonpervasive event Symmetric andByzantine fault Fault tolerant

فيض رسان، حسين

تشخيص رخداد با تحمل پذيري خرابي در شبكه هاي حسگر بي سيم

رخداد فراگير و غير فراگير , خرابي متقارن و بيزانتين