Abstract:
The purpose of this research is to construct fuzzy expert system to estimate an integral degree of market
concentration by fuzzy-logical approach. The methodological basis of the study consists of scientific works of
domestic and foreign scientists and leading specialists, statistical and analytical materials of state authorities. Fuzzy
Inference is introduced for the integrated indicator construction. Two indicators are chosen as input variables.
The first indicator, CR, is a level of concentration ratio. The second indicator, HHI, is the Herfindahl-Hirschman
index. Output variable, MC indicator, means a degree of market concentration. Both input and output variables
are transformed to fuzziness through the construction of membership function. The function type and parameters
are substantiated and “bell”-shaped membership function to describe uncertainty of the values falling under
normal distribution is chosen. The quantity of fuzzy sets at every input is considered z=3 and the quantity of input
variables is considered ω=2. To achieve completeness of the model, the quantity of logic rules is considered r=3²=9.
To calculate a degree of market concentration, Mamdani fuzzy conclusion is applied. Defuzzification is engaged to
calculate value of the output variable which is MC indicator to mean a degree of market concentration and therefore
readiness to implement the innovation strategy for enterprises active in innovation. To estimate a degree of market
concentration, the fuzzy expert system given allows for engagement of different indicators due to fuzzy logic
methodology which considers fuzziness of the input and output variables. The construction of an integral indicator
for assessing the state of economic competition in order to establish the feasibility of identifying operators and
providers with a significant market advantage will improve the assessment of the state of economic competition in
the market in the telecommunications services market in Ukraine.
