The application of fuzzy logic for profit optimization to contractor project cash flow

Abstract

Profit has become the main goal for a contractor without neglecting other aspects in the content of contract. According to previous empirical studies, profit has been optimized. However, it was optimized not as an output variable. Therefore, in this study we were going to try to position profit as an output variable using Fuzzy logic. The research aimed to: 1) describe cash in and cash out to prepare empirical Project Cash Flow (PCF) statement, 2) develop Fuzzy Mamdani set model on PCF 3) formulate manual method and Fuzzy Mamdani computational programming on PCF, 4) validate the results of manual simulation using computation, and 5) make profit which can be simulated. The results of the study were: 1). Fuzzy Mamdani set model with 4 input variables (%), those were: Direct Cost (7-75), Indirect Cost (2-25), Informal cost (1-15) and Progress (0-100) and single output which was profit (0 - 10); 2). The manual method consisted of 4 stages: (1) creating a fuzzy set of 4 input variables and 1 output variable, (2) making the Application Function Implications based on 2 rules, (3) Composing all output variables with the MAX operation, and (4) Defuzzification using the method of centroid of area, 3). computational way with indicators: Trapezoid membership function, two-type linguistic set (minimum - maximum) and (slow - fast), MISO (Multiple Input Single Output) implication functions, “MAX - DOT” operation system, fuzzy rules (if … and … then) = 16 rules, 4). The output of the manual method and computational method resulted the same profit of 4.46, so it was declared valid, and 5). The simulation revealed that minimum profit can be made if the cash out allocation and progress on input variables are not balanced and in contrast, we will obtain maximum profit if the allocation of cash out and progress are balanced with input variable.