Analysis of Stability Degree for Combustion of Waste-to-Energy Plants with Fuzzy Relational Map of Sensors — Improvement of Important Degrees of Fuzzy Sets of Sensors

Abstract

In Waste-to-Energy plants, combustion is dependent on many complex factors and a sign of unstable states appears in other locations. We have proposed a fuzzy relational map of sensors (FuRMS) for expressing relationships between many sensors as relations between fuzzy sets of sensor values. We calculate importance degrees between fuzzy sets of sensors of the same combustion states. For data of unknown states, we calculate an evaluation value as weighted average of importance degrees of all pairs by the products of matching degrees of fuzzy sets of sensors to get a degree how close the data is to the combustion state of the map. The number of pairs of sensors with strong relations get small when the number of weak relations get large. We have proposed a method to subtract a fixed value from fuzzy counts of data in a calculation of importance degrees. It decreases the importance degrees of pairs with strong relations, but the change of evaluation values becomes like those without subtractions. In this paper, we propose a method to subtract the average entropy of relations of fuzzy sets from the importance degrees. However, a change of evaluation values with this method are not significantly difference from the method without subtractions. We also propose a method to ignore weak relations whose importance degree below a threshold value. It can slightly identify combustion states compared to the previous method.