In this study, the authors have experimentally established an assessment rule of debris flow torrents applicable to degree of disaster risk. For the first trial, the representing hazard data were selected by eliminating surrounding noises as much as possible by means of SVM method. Second, the disaster risks were classified respectively by using separating hyperplane constructed by the selected representing hazard data. Then, each hazard rank was studied and analyzed by application of rough set theory, so that the assessment rule has been established. The rule through this process has high versatility, and has a good consistency with actual events of disaster occurrence or non-occurrence. From the method above mentioned, the results of this study, show that the most appropriate rule can be selected from survey data of any debris flow torrents and the system can be applicable to utilize for the judgment of hazard rank, as well.

View full abstract

 When information of motor vehicle collision to a steel bridge girder of railway overbridge was received, the accident situation and degree of damage of the girder should be confirmed. However, there is a problem that a train service might be delayed due to time-consuming safety confirmation. Therefore, only to detect impact force inducing deformation, damage and movement of bridge girder, resulting into delay of train service, the strength of bridge girder and harmful impact force were calculated. Simultaneously, a system to detect the harmful impact force was developed and a tolerance for the detection was determined. From the above results, the method to detect the harmful impact force was developed and put into practical use.

View full abstract

 BCP (Business Continuity Plan) is important to reduce indirect damage caused by disaster. However, many companies have not yet developed a BCP because the effect of BCP is not clear. Therefore, this paper aims to analyze the damage characteristics and the effect of early restoration of business due to the BCP, using the data of listed companies, whose shares are quoted on stock exchange, damaged by the Great East Japan Earthquake. As a result, it turned out that the companies that had developed their own BCP had recovered earlier on average. It was also observed that the worksites, which had been damaged by tsunami or liquefaction, took more than twice recovery period as compared with worksites that had been damaged by ground motion.

View full abstract