How Does a Fuzzy Logic System Work

Within a fuzzy system, an inference engine works with fuzzy rules it takes input, part of which may be fuzzy, and generates output, some or all of which may be fuzzy. Although the role of a fuzzy system is to deal with uncertain data, the input is itself not necessarily fuzzy. For example, the data fed into the system might consist of the pH of a solution or the molecular weight of a compound, both of which can be specified with minimal uncertainty. In addition, the output that the system is required to produce is of more value if it is provided in a form that is crisp Set the thermostat to 78°C is more helpful to a scientist than raise the temperature of the oven. Consequently, the fuzzy core of the inference engine is bracketed by one step that can turn crisp data into fuzzy data, and another that does the reverse. 

We will outline the way that a fuzzy system makes deductions using an example from enzyme kinetics. 

The rate of a reaction catalyzed by an enzyme depends on several factors, in particular, the concentrations of enzyme and substrate, [E] and [S]. As the concentration of enzyme increases, the rate rises, though as 

We could express the activity of fumerase as a function of pH in the fuzzy rules  

Rl IP the pH is medium AND the enzyme concentration is high THEN the reaction rate is high. 

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