Knowledge Representation and Reasoning with an Extended Dynamic Uncertain Causality Graph under the Pythagorean Uncertain Linguistic Environment

• Published in: Applied sciences Vol. 12; no. 9; p. 4670
• Main Authors: Zhu, Yu-Jie, Guo, Wei, Liu, Hu-Chen
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.05.2022
• Subjects: Algorithms; Causality; dynamic uncertain causality graph (DUCG); evaluation based on distance from average solution (EDAS); expert system; Fault diagnosis; Fuzzy sets; Knowledge acquisition; Knowledge representation; knowledge representation and reasoning; Linguistics; Literature reviews; Methods; Nuclear power plants; Pythagorean uncertain linguistic set; Subject specialists; Variables
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app12094670

A dynamic uncertain causality graph (DUCG) is a probabilistic graphical model for knowledge representation and reasoning, which has been widely used in many areas, such as probabilistic safety assessment, medical diagnosis, and fault diagnosis. However, the convention DUCG model fails to model experts’ knowledge precisely because knowledge parameters were crisp numbers or fuzzy numbers. In reality, domain experts tend to use linguistic terms to express their judgements due to professional limitations and information deficiency. To overcome the shortcomings of DUCGs, this article proposes a new type of DUCG model by integrating Pythagorean uncertain linguistic sets (PULSs) and the evaluation based on the distance from average solution (EDAS) method. In particular, experts express knowledge parameters in the form of the PULSs, which can depict the uncertainty and vagueness of expert knowledge. Furthermore, this model gathers the evaluations of experts on knowledge parameters and handles conflicting opinions among them. Moreover, a reasoning algorithm based on the EDAS method is proposed to improve the reliability and intelligence of expert systems. Lastly, an industrial example concerning the root cause analysis of abnormal aluminum electrolysis cell condition is provided to demonstrate the proposed DUCG model.