Comprehensive Risk Evaluation Analysis of Sea Waterway Nautical Navigational Environment Based on Fuzzy Theory
The nautical navigational environment (NNEt) is a subsystem of the waterway transportation system (WTS) composing of ‘human-machine-environment’. NNEt of sea waterway is closely related to navigation safety. It is necessary to identify, assess and prevent risks in NNEt to ensure safe operation of WTS. It is also of great significance to identify and evaluate risk of NNEt scientifically and reasonably for shipping development. Tiaozhoumen Waterway is one of the important passages for ships’ entering and leaving Ningbo-Zhoushan Port. It is of great significance to identify and evaluate NNEt risk of the water way for taking safety guard measuares. In this paper, a method flow for risk evaluation analysis of NNEt based on fuzzy theory is proposed, and applied to comprehensive risk evaluation of Tiaozhoumen Waterway, Zhoushan Port. Risk factors in NNEt of Tiaozhoumen Waterway are identified using a systematic and hierarchical way. The membership degree to any of the five fuzzy concepts (the linguistic terms for indicating risk level) is obtained based on fuzzy statistical method. The weighted average method is used to defuzzy, in order to obtain quantitative evaluation results of concerned risk factors. Then, relative importance of risk factors are compared from perspective of the significance of risk. The research results of risk identification and evaluation can provide basis or reference for taking different and targeted risk prevention measures.