Research On The Combination Of Conflict Evidence In D-S Evidence Theory

D-S evidence theory is method of dealing with uncertainty caused by unknown factors.It has been widely applied to the fields of information fusion,decision analysis,pattern recognition,fault diagnosis,and some good results had been obtained.However,there are still some problems which are needed to be solved in the practical application of D-S evidence theory,especially the conflict evidence combination problem which has attracted lots of attention from scholars.Based on the idea of modifying the original evidence,the dissertation studies the conflict evidence combination problem.The main innovation are as follows:(1)In response to the phenomenon that the Dempster combination rules has “one ticket veto” and weak decision-making evidence in low-conflict situations,a synthesis method based on similarity function of Vague set is proposed.This method uses the similarity of universe of discourse between Vague sets at first,then the similarity between evidence can be obtained by combining the trust function and likelihood function of evidence.And the support between the evidence can also be obtained.Furthermore,the discount factor is determined.It uses D-S combination rules to synthesize and use the discount factor to correct the evidence source at last.Numerical examples show that the proposed method can effectively weaken the effect of “one ticket veto” on combination results,effectively improve the conflict evidence combination problem containing weak decision evidence,and raise the rationality and reliability of decision-making results.(2)Aiming at poor robustness of Dempster combination rule,Zadeh paradox and failure of Dempster combination rule in high conflict of evidence,the paper proposes conflict evidence combination method based on compatibility coefficient.First,the support and discount factors of evidence sources are obtained based on the consistency coefficient between the evidence and the similarity of Vague sets.And then Taking the average of two discount factors as the final discount factor,and finally the source of evidence is synthesized and revised by using the D-S synthesis rule.The numerical examples indicate that the improved method can effectively solve the one-vote veto,robustness problem,Zadeh paradox and Dempster combination rule in synthesizing the failure of high-conflict evidence,and it has good convergence.