Abstract: This paper discusses potential application of fuzzy set theory, more specifically, pattern
matching, in assessing risk in chemical plants. Risk factors have been evaluated using
linguistic representations of the quantity of the hazardous substance involved, its
frequency of interaction with the environment, severity of its impact and the uncertainty
involved in its detection in advance. For each linguistic value there is a corresponding
membership function ranging over a universe of discourse. The risk scenario created by a
hazard/hazardous situation having highest degree of featural value is taken as the known
pattern. Each sample pattern of hazard/hazardous situation with their known featural values
is then matched with the known pattern. The concept of multifeature pattern matching based
on fuzzy logic is used to derive the rank ordering of process hazards. In multifeature
pattern recognition/matching, a sample pattern is compared to a number of known data
patterns or a known pattern is compared to a number of sample data patterns. The process
assesses which known pattern resembles most closely data sample using Wang’s approaching
degree method. A methodology has been developed and the same has been exemplified by
presenting a case example with a limited number of hazards.

Key words: risk, chemical process, fuzzy set, pattern matching

摘要： This paper discusses potential application of fuzzy set theory, more specifically, pattern
matching, in assessing risk in chemical plants. Risk factors have been evaluated using
linguistic representations of the quantity of the hazardous substance involved, its
frequency of interaction with the environment, severity of its impact and the uncertainty
involved in its detection in advance. For each linguistic value there is a corresponding
membership function ranging over a universe of discourse. The risk scenario created by a
hazard/hazardous situation having highest degree of featural value is taken as the known
pattern. Each sample pattern of hazard/hazardous situation with their known featural values
is then matched with the known pattern. The concept of multifeature pattern matching based
on fuzzy logic is used to derive the rank ordering of process hazards. In multifeature
pattern recognition/matching, a sample pattern is compared to a number of known data
patterns or a known pattern is compared to a number of sample data patterns. The process
assesses which known pattern resembles most closely data sample using Wang’s approaching
degree method. A methodology has been developed and the same has been exemplified by
presenting a case example with a limited number of hazards.

关键词: risk;chemical process;fuzzy set;pattern matching