Research On Railway Emergency Management Evaluation And Decision-making Based On Fuzzy Theory

In recent years,China's railway system has rapidly developed toward the directions of high-speed passenger transport,heavy-duty freight,management informatization and marketizing operation,which make the complicated railway system more complicated.In the new environment,more and more elements are contained in the new system,the linkages between the elements are getting more closely,and the standard requirements of the elements get to be higher.These lead the system to the situation that the system has to be confronted with more uncertain and unstable disturbing factors,and these disturbing factors have greater disturbance to the railway system.In order to avoid or reduce the harm caused by all kinds of the railway emergencies,the railway system has built up the railway emergency management system which is made up of the organization system,the mechanisms system,legal system,the emergency plans,the guarantee system and the railway emergency information system.Remarkably,the scientific management is inseparable from the evaluation and decision-making activities:the evaluation activities of the objects of emergency management can make the subjects deeply understand the object and clear the feasible response or improvement measures;the decision-making activities can help the subjects determine the most feasible action plan to guide the future work.However,the evaluation and decision-making activities have not got the enough attention in the railway emergency management,which not only lies in less consciousness of scientific management,also lies in that the perfect,effective system and mechanisms of evaluation and decision-making system have not yet constructed and the evaluation and decision-making model with high operability and effectiveness have not been proposed.With respect to the problems,this paper aims to construct the system and mechanism of railway emergency management evaluation and decision-making activities,and propose the corresponding evaluation and decision-making model based on the fuzzy theory.The main research work of this paper includes the following aspects:1.The mechanism construction of railway emergency management evaluation and decision-making.Within the framework of railway emergency management system,the related issues of railway emergency management evaluation and decision-making activities are discussed in depth from the aspects of the specific content,concept definition and the relationship between the activities and emergency management.And then,the mechanisms of railway risk evaluation,railway emergency plan evaluation,railway emergency capability evaluation and railway emergency decision-making are proposed form the following four aspects:subjects,objects,methods and procedures.2.The construction of railway risk evaluation model.Combining the PD-HFLTS and the traditional risk assessment methods,the railway risk evaluation model is constructed,in which possibility distribution-hesitant fuzzy linguistic term set(PD-HFLTS)is utilized to characterize the fuzzy and uncertain assessment information and the group consensus checking and adjusting algorithm is put to deal with the clash of opinions in the group evaluation process.The specific process is divided into the following three steps:firstly,the risk possibility is determined utilizing the fault tree analysis method based on PD-HFLTS;secondly,the consequence severity is obtained from the following three aspects:casualties,direct economic losses and service disruption time;and then,the risk matrix is used to determine the risk level and preventive and control measures is proposed pertinently.3.The construction of railway emergency plan evaluation model.Referring to the ideas of QFD in analyzing the relationship between demand and supply,the model is constructed from the demand and supply aspect to determine the key content and the deficiencies of the plan.Firstly,the operators and programmers of the plan are determined,afterwards the requirement items,the content items and the relationship between requirements and contents of the plan are determined.Secondly,the basic importance ratings of content items are obtained with the help of the basic importance ratings of requirement items,the modified importance ratings of requirement items and the relationship matrix between requirements and contents.After that,the modified importance ratings of the content items are got by the information of improvement space and improvement feasibility,and then the comprehensive importance ratings of the content items are obtained.Finally,the key content and the deficiencies of the plan can be confirmed based on the above analysis results.Furthermore,the evaluators are asked to utilize the PD-HFLTS to characterize the evaluation information and a group consensus checking and adjusting algorithm is put forward to deal with the clash of opinions.4.The construction of railway emergency capability evaluation model.Firstly,the evaluation criterion system is proposed from the two dimensions of emergency management process and emergency management system.Secondly,taking into account the risk preference of the evaluators in the face of the evaluation problem based on the reference point,the evaluation information given by the evaluators is revised by using the value function of the prospect theory.And then,with respect to correlation ship among the various management measures,a new correlation weight determined model is proposed based on DEMATEL and AHP.In the evaluation process,the evaluators utilize the PD-HFLTS to characterize the evaluation information,and a group consensus checking and adjusting algorithm is put forward to deal with the clash of opinions.5.The construction of railway emergency decision-making model.The model asks the decision-makers to utilize the PD-HFLTS to characterize the decision information,and a group consensus checking and adj-usting algorithm is put forward to deal with the clash of opinions in the group decision-making process.Considering the correlation between the evaluation indexes,a new method based on ANP and DEMATEL is put forward to determine the indexes' correlation weight which can effectively characterize the relative influence degree and the relation importance of indexes.With respect to the risk preference problems,the value function in the prospect theory is used to update the profit and loss value with the reference value of expectations and minimum requirements.In the light of TOPSIS,the weighted subjective perceived Euclidean distances between the alternatives and expectations or minimum requirements are constructed and the best plan is determined based on the closeness degree to the expectation level.