# An Operations Chain Model for Automatic Assessment of Operation Procedure for Equipment Operators
###### Abstract
Generally, in the aforementioned methods, there is only one standard operation pathway, which cannot comprehensively and objectively reflect the proficiency of all operators. [PERSON] [6] proposed an assessment method based on the maximum matching principle to match and color the trainee's operation sequence. The method introduced a new way of solving the problem. The method can assess the trainee's operation sequence based on the standard operation sequence provided by the instructor. The method also involved the determination of the sequence and steps of the trainee's operations. However, the method required a unique and strictly ordered standard operation sequence and relied on the instructor's observation due to the lack of sequence alignment algorithms. Furthermore, there are certain limitations in practical applications because of the lack of a model to describe all possible operation paths. To address the issue, this study focuses on the behavioral patterns reflected by the operation procedure and conducts an analysis, in detail, of the relationships among equipment operations. A comprehensive operation description model, named the operations chain model, is established that can record the operation sequence and pathway, facilitates automatic assessment, and possesses a carefully designed structure. The model is applied to describe the combination of the standard operations for a certain task. Each operation can be represented by a number or a letter and an operation sequence can be obtained after a trainee finishes an operation task. The standard operations described by the operations chain model can also be transformed into one or more standard operation sequences. By utilizing the double sequence alignment algorithm, the operation sequence can be aligned with the standard sequence and the similarity between the two operation sequences can be calculated. The similarity can serve as the score for the trainee's operations, which is an essential component of the trainee's assessment. However, there is no double sequence alignment algorithm applied for operation sequence alignment. The double sequence alignment algorithm is commonly used for gene sequence alignment problems in bioinformatics to analyze the similarity between two gene sequences. [PERSON] et al. [7] applied the algorithm to metropolitan travel mode recognition based on mobile phone data. The algorithm was also applied to the comparison of user trajectories based on GPS (Global Positioning System) by [PERSON] et al. [8]. [PERSON] et al. [9] used the algorithm to measure navigation disorientation in web-based systems. The algorithm works effectively in those areas. In the double sequence alignment, the matching procedure for sequence S1 and sequence S2 is regarded as a two-dimension matrix. There are three kinds of results when comparing the values of two elements located in the same column in the matrix: a match when they have the same value; a mismatch when the contents are different; and an insertion or deletion when the corresponding locations have a vacancy. It matches well with the concepts of the correct operation, the incorrect operation, and the miss-operation in the operation sequence on equipment, which makes it suitable for operation procedure assessment. The double sequence alignment algorithm can dynamically adjust the two sequences following dynamic programming ideas, and optimal alignment results can be obtained. Therefore, the reliability of the assessment will be improved. The most classic double sequence alignment algorithms include the Needleman-Wunsch algorithm and the Smith-Waterman algorithm [10]. The Smith-Waterman algorithm is based on local alignment and can only obtain the sequence with matched elements. The Needleman-Wunsch algorithm is based on global alignment and can obtain the dynamically adjusted sequence alignment result by backtracking techniques. Since the operation sequences are usually short, the Needleman-Wunsch algorithm is chosen to implement the alignment and scoring of the operation sequences.