# An Operations Chain Model for Automatic Assessment of Operation Procedure for Equipment Operators
###### Abstract  
Automatic assessment of the operation ability of operators based on computers is an essential approach for improving the effectiveness of equipment operation training and enhancing equipment safety. Present methods primarily focus on the operation results but pay less attention to the operation procedure. One reason is that there is a lack of a model that has the ability to describe all probable paths to accomplish the same task. Therefore, an operations chain model is put forward for the first time to describe the standard operation procedure and relationships among operations based on the decomposition of operational tasks and the relationships among the various operations required to fulfill the task. A specific operation task corresponds to an operations chain, which will form one or multiple standard operation sequences that will allow trainees to complete the same task through different paths. The Needleman-Wunsch sequence alignment algorithm is introduced to match the trainees' operation sequence with all standard sequences. The maximum alignment result is the score of the trainees' operations. An example shows that the operations chain model can accurately describe the complex structure of the standard operating procedures. The Needleman-Wunsch sequence alignment algorithm can objectively evaluate the trainee's operation capabilities. The combination of the operations chain model and sequence alignment algorithm can form a complete operation procedure assessment method that is friendlier to trainees and has more objective evaluation results. The method will help to improve the effectiveness of the competency assessment of equipment operators. automatic assessment; operations chain model; operation procedure; Needleman-Wunsch alignment algorithms +
Footnote †: journal: Applied  
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and synthesis method, and the operation errors were divided into five categories: missed operations, extra operations, sequential errors, repeated operations, and timing errors. The expert system was applied to find operation errors by comparing it with the operation sequence specified in the operation manual. The final score was obtained by subtracting error scores from the total score. There was only one standard operation sequence. However, in many cases, the trainee could complete the operation task through different correct ways. The method was not applicable to this situation. Furthermore, the weighting of errors was obtained by expert knowledge. [PERSON] et al. [4] established a combined weighting model in which the subjective weights were determined by the C-OWA (Combination-Ordered weighted averaging) operator weighting method, and the objective weights were determined by the coefficient variation method. A vague set was incorporated to address the ambiguity issues in the assessment process. The method had a good evaluation result on equipment process data but paid no attention to the operations procedure. Therefore, the result of this method could not fully reflect the trainee's operational ability. [PERSON] et al. [5] developed an intelligent assessment system based on a hierarchical structure of criteria that could make effective judgments on operation results. The article paid no attention to the operation procedure. The abovementioned literature mainly employed an expert system, analytic hierarchy process, and fuzzy comprehensive evaluation method to assess the operation results and changes in equipment status and achieved satisfactory results. However, less attention was paid to the operation procedure. For complex equipment, there may be many operation steps and paths to complete a certain task. The sequence of operations can also be different. There are some options that operators can choose from. Different operation paths will bring different intermediate results and may result in different assessment results, although they accomplish the same work successfully. Therefore, methods that can assess the operation procedure are needed.