Application of set pair analysis method on occupational hazard of coal mining

As platforms age, there are increasing challenges to perpetuate their integrity. Currently, process of life extension and repair decision-making model in ageing offshore platforms which was based on DHGF algorithm was established built in order to make reasonable predictions about of life of ageing offshore platforms, and to make accurate repair decisions and to reduce their risks under uncertain and complicated environment. A decision on whether to install new equipment or recondition existing ones could then be taken in terms of optimal life-cycle cost, reliability, project budgets and safe state. There were 18 indicators based on Delphi method for evaluation system. Hierarchical structures were set up by analyzing and adjusting four dimensions - project factors, risk factors, load factors and structure factors which affect the ageing platform service state. Weighted subset was determined by Analytic Hierarchy Process (AHP). Then, we can calculate the gray weights using the gray model theory. The next step is that, it applied fuzzy mathematics to determine the grade evaluation of ageing platform. The evaluation criteria of life extension and repair decision-making model in ageing offshore platforms were established. The comprehensive score was calculated by a sequence of computational steps. Furthermore, life extension and repair decision-making reference table was set up and the period of life extension and repair grade in offshore platform was determined in the light of this table. Life extension and repair decisions for two platforms were made by using this new model and the results were compared with the traditional methods. Research results display that this model can describe the dynamic economic lifetime of ageing offshore platforms more accurately and give a new resolution for the research of life extension and repair decision-making under uncertain and complicated environment.