Cognitive Radio(CR) is a promising technology to solve the challenging spectrum scarcity problem.However, to implement CR, spectrum sensing is the groundwork and the precondition.In this paper, a collaborative spectru...Cognitive Radio(CR) is a promising technology to solve the challenging spectrum scarcity problem.However, to implement CR, spectrum sensing is the groundwork and the precondition.In this paper, a collaborative spectrum sensing scheme using fuzzy comprehensive evaluation is proposed.The final sensing decision of the proposed scheme is based on the combination of distributed sensing results of different Secondary Users(SUs).To improve the reliability of the sensing decision, the combination procedure takes into account the credibility of each SU, which is evaluated using fuzzy comprehensive evaluation.The effect of the presence of malicious SUs and malfunctioning SUs on the performance of the proposed scheme is also investigated.The efficiency of the scheme is validated through analysis and simulation.展开更多
油气集输系统中的风险因素数量庞杂,各风险因素相互关联,且对系统整体的安全功能作用不同。因此,对风险因素进行层次筛选是提高风险评价效率和准确性的有效途径。首先采用事故树分析(Fault Tree Analysis,FTA)系统辨识风险因素,根据Del...油气集输系统中的风险因素数量庞杂,各风险因素相互关联,且对系统整体的安全功能作用不同。因此,对风险因素进行层次筛选是提高风险评价效率和准确性的有效途径。首先采用事故树分析(Fault Tree Analysis,FTA)系统辨识风险因素,根据Delphi方法进行风险因素初次筛选,并对筛选出的风险因素进行聚簇。然后,利用模糊认知图(Fuzzy Cognition Maps,FCM)对风险因素进行二次筛选,基于权重排序得到风险评价因素集。最后,利用模糊综合评价方法(Fuzzy Comprehensive Evaluation,FCE)进行风险等级的定量计算,并对风险评价方法过程进行了分析设计。结果表明,该研究提高了油气集输系统风险评估工作的科学性,对制定较强针对性的风险控制策略具有重要意义。展开更多
基金Supported by the National Natural Science Foundation of China (No.60672079)the Natural Science Foundation of Jiangsu Province (No.BK2006701 and No. BK2007002)
文摘Cognitive Radio(CR) is a promising technology to solve the challenging spectrum scarcity problem.However, to implement CR, spectrum sensing is the groundwork and the precondition.In this paper, a collaborative spectrum sensing scheme using fuzzy comprehensive evaluation is proposed.The final sensing decision of the proposed scheme is based on the combination of distributed sensing results of different Secondary Users(SUs).To improve the reliability of the sensing decision, the combination procedure takes into account the credibility of each SU, which is evaluated using fuzzy comprehensive evaluation.The effect of the presence of malicious SUs and malfunctioning SUs on the performance of the proposed scheme is also investigated.The efficiency of the scheme is validated through analysis and simulation.
基金The financial support from National NatureScience Foundation (30400137)National Natural FoundationCommission,the Civil Aviation Science Foundation(60672181)China Postdoctoral Science Research Foundation(2004035033)