An accident analysis model oriented to complex tasks process

Accident model,i.e. accident-causing theory, that is a main component of Principium of Safety, is an important part of accident theory. It avoids concrete characteristic of hazard source and content and mode of accident temporarily. Instead, abstractly thinking of person, machine, goods and environment in system, revealed accident causes, processes and results in nature.After many researches, it appears Heinrich Chain Model, Adams Chain Model, Epidemic Pathology Model and System Attribution Model successively. The last stage of accident model development is System Attribution Model, including typically Surry Model, Orbit Intersecting Theory and STAMP Model, all deemed there is no constant event sequences in accident evolution. Once multi-factors, such as person, machine and environment, are interacted on each other in time and space, it maybe leads to accident. System Attribution Model has shown the importance of multiple factors interaction in accident evolution in theory, however, no interpretation for multiple factors interaction (coupling) model. Also, on the technical level, it has not proposed systematic method to analyze multi-factors problems in complex tasks process. According to above problems, this paper proposes an accident analysis model oriented to complex tasks process. Including 1) Establish the accident analysis model oriented to complex tasks process; 2) Present a new method, process breakdown structure(PBS), involving process-dimensional breakdown and object-dimensional breakdown. Though PBS we can resolve complex tasks process into interrelated or interactive activities by transforming from input to output. 3) As the multi-factor coupling relationship is complex, this paper proposes single coupling -, correlative coupling (including Series coupling, Parallel coupling, Series-parallel coupling-, Ring coupling), Control coupling, and so on, meanwhile gives the specific multi-factor coupling analysis method. This model expounds the cause of the acci- - dent by analyzing the complex process and multi-factor coupling. Though studying different evolution paths of system status in complex tasks processes, we could exposit accident causes, developments and results, that to lay the foundation for launching accident prevention.