The dissimilarity measure of reasonable evidences is the basic issue of both static and dynamic reliability assessment. For example, dissimilarity measures among evidences are unreasonable in Guo’s  and Elouedi’s method . Moreover, some methods use information inadequately, such as Elouedi’s Tf  and Yang’s method . In addition, the research on methods of combining static and dynamic discounting factors is not deep enough, which is just mentioned in . This combination method has no ability to adapt to the performance changes of sensors.In order to resolve the above problems, this paper puts forward a scheme of sensor reliability evaluation and evidence discounting, which mainly includes two parts.
First, we have designed an improved dissimilarity measure based on a dualistic exponential function so as to assess the static reliability from a training set by local decision of each sensor and distance measure between evidences. The dynamic reliability factors are gained from every test target by dissimilarity measures between the output information of each sensor and the consensus of total evidences simultaneously. Second, we have introduced an adaptive combination method of static and dynamic discounting based on fuzzy theory and Parzen-window density estimation, which can be suitable for different kinds of uncertain target environments.The rest of the paper is divided into six parts. Section 2 reviews the belief function theory. An improved dissimilarity measure based on a dualistic exponential function is presented in Section 3.
Evaluation methods of static and dynamic discounting Anacetrapib factor are respectively introduced in Section 4. In Section 5, we propose an adaptive combination mechanism of static and dynamic reliability discounting. The experiments and analysis are arranged in Section 6, where we compare the proposed method with other methods on real datasets. Then, a conclusion is presented in Section 7.2.?Basic Concepts of the Belief Function TheoryBelief function theory is regarded as a useful tool of representing and processing uncertain knowledge. In this section, a brief review of the belief function theory is introduced.2.1. Main FunctionLet �� = ��1, ��2, ��, ��p be a finite set of all possible results to a given problem, which is named as the frame of discernment. All the elements of �� are exclusive and exhaustive, and belong to the power set of ��, denoted as 2��. The subsets of �� containing only one element are called singletons.Definition 1: Given a set of evidence provided by the sensor, intelligent agent defines the corresponding basic belief assignment on �� as a function m��:2�� �� [0,1], which satisfies:��A?��m��(A)=1(1)If there is no ambiguity, m�� may be abbreviated to m.