Research On Safety Evaluation Of Departure In Poor Visibility Based On Fuzzy Petri Nets Theory

With the continuous development of world industrialization,air pollution and bad weather of poor visibility caused by fog and haze frequently appears,which poses a great threat to the safety of departure,resulting in the failing of ships' departure according to the vessel schedule,which seriously affecting the utilization of port channel,wharf as well as the operating efficiency of ship management companies,and restricting the healthy development of port economy and shipping economy.The current research takes the issue of safety of departure in poor visibility as the research object.Through evaluating safety of departure in poor visibility,it aims to provide reference for the port to adjust the policies of departure prohibition or restriction in poor visibility,and provide the theoretical support for ship management companies and ships to sail safely in poor visibility.Firstly,this paper makes a review of the current research status of safety of departure in poor visibility at both China and abroad.Additionally,it concludes and analyzes major ports'policies of departure prohibition or restriction in poor visibility.Then,based on the analysis of various elements that affect safety of departure in poor visibility,an evolution index system for safety of departure in poor visibility is set up,including four second-level indicators,that is,staffs,ships,environments and shore based guarantee,and 14 third-level indicators.It also analyzes the indicators' evolution methods,adopting cloud model to change the indicators into qualitative ones,and the evaluation model for safety of departure in poor visibility based on dynamically variable weight fuzzy Petri net is finally constructed.This evolution model is verified at Qianwan harbor area,Qingdao port in this paper,attesting the validity and availability of this evaluation model.This paper gives some further advices to improve the safety of departure in poor visibility.The evaluation model for safety of departure in poor visibility in the current research enriches the relevant studies in the field of maritime safety assessment to a higher level.Evaluating the safety of departure in poor visibility from the perspective of combining qualitative and quantitative method provide an important guidance to the maritime industry.