International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-9 Issue-1, October 2019 Effect of Crossover Probability on Performance of Genetic Algorithm in Scheduling of Parallel Machines for BI- Criteria Objectives Raghavendra B V Abstract: Optimization of multi objective function gain the • Utilization of the systems importance in the scheduling process. Many classical techniques • Rate of production are available to address the multi objective functions but the Minimizing the solutions yield the unsatisfactory results when the problem • Workload imbalance on machines becomes complex and large. Evolutionary algorithm would be the • Manufacturing lead time solution for such problems. Genetic algorithm is adaptive heuristic search algorithms and optimization techniques that • Penalty cost mimic the process of natural evolution. Genetic algorithms are a • Work-in-process jobs very effective way of obtaining a reasonable solution quickly to a • Setup and tool changes times complex problem. The genetic algorithm operators such as Most of the studies have considered single-criteria selection method, crossover method, crossover probability, algorithms. However, a new scheme of the multi-criteria mutation operators and stopping criteria have an effect on algorithms has been proposed in recent years. These obtaining the reasonably good solution and the computational algorithms do not transform a multi-criteria problem into a time. Partially mapped crossover operators are used to solve the single. Simultaneous optimization of all objective functions in problem of the traveling salesman, planning and scheduling of the machines, etc., which are having a wide range of solutions. the real time environment is challenging and conflicting with This paper presents the effect of crossover probability on the each other objective functions. Optimization of any one performance of the genetic algorithm for the bi-criteria objective objective function may not optimize the other objective function to obtain the best solution in a reasonable time. The function. Hence it is necessary to find a better solution that simulation on a designed genetic algorithm was conducted with a would compromise all the objective functions in the multi crossover probability of 0.4 to 0.95 (with a step of 0.05) and 0.97, objective environment. Literature shows that, researchers found that results were converging for the crossover probability of have developed various methodologies broadly based on 0.6 with the computational time of 3.41 seconds. classical mathematical approach, heuristic based and hybrid Keywords: Genetic Algorithm, Crossover probability, method to obtain the best solution in the multi-criteria Bi-criteria objective, Scheduling, Parallel machines. objective environment of the scheduling process. They have studied various traditional, mathematical, heuristic and I. INTRODUCTION metaheuristic tools to obtain a reasonably good solution. The Scheduling process is the crucial task in the ever Many studies have been carried out on the evolutionary changing production process to meet the customer demand at approach such as genetic algorithm (GA), ant-colony the earliest possible time. Scheduling is the process of optimization (ACO), particle swarm optimization (PSO), artificial intelligence etc. Birch [1], H. Nazif [2], Dr. Rakesh allocation of resources over time and workload on the Kumar [3], S.Ramya [4], Moin et.al [5] have used the genetic machines systematically to meet the objective function for algorithm approach to meet the objective function. The optimization in the production process. The systematic genetic algorithm operating parameters such as population allocation of workload and resources helps the decision size, selection method, crossover, mutation method and makers in analyzing the effectiveness of the production stopping criteria have an effect on the performance of the process and deciding the best method. The scheduling is the algorithm in the dynamic situation. The performance of the complex task and helps to meet some of the objectives of the algorithm depends on the convergence of the solution and the production process such as, to reduce manufacturing lead computational time. Simulation has been done in this paper to time, reduction in-process jobs, on-time delivery or to reduce analyse the effect of crossover probability on objective the penalty cost, reduce the workload imbalance and many function such as minimizing the total cost and computational more. The researches have considered some of the most time.In the genetic algorithm, the parent chromosomes are important objectives in the context of a batch production selected from the population to crossover. Darwin's evolution environment, are theory states that the best chromosomes should further survive Maximizing the and create new offspring. In the genetic algorithm the selection of parent chromosomes based on different selection operator methods such as a roulette wheel, Boltzman, tournament, rank, steady state, stochastic universal sampling, Revised Manuscript Received on October 15, 2019. linear, exponential rank, Dr. Raghavendra BV, JSS Academy of Technical Education, truncation, and many more [6]. Bengaluru-560060, India. Email: [email protected] Published By: Retrieval Number: A9801109119/2019©BEIESP 2827 Blue Eyes Intelligence Engineering DOI: 10.35940/ijeat.A9801.109119 & Sciences Publication Effect of Crossover Probability on Performance of Genetic Algorithm in Scheduling of Parallel Machines for BI- Criteria Objectives Crossover is one of the prominent operators used in genetic reversing mutation, inversion mutation, creep mutation, algorithms. The crossover process is vital in generating new scramble mutation, flip mutation, uniform mutation, flip bit, chromosomes by combing two or more parent chromosomes boundary, uniform and many more [16]. with the hope that they create new and efficient chromosomes. Stopping criteria is also a very important parameter in the Parent chromosomes are selected based on a selection genetic algorithm. The algorithm should continue to search operator to create the new offspring of the child‟s for convergence solutions and stop if no better solution exists. chromosomes. During crossover the parent chromosomes are In the real time dynamic scheduling process the taken in pairs and their genes are exchanged in a certain order, computational time of the algorithm plays a major role. Hence based on the type of crossover method and crossover the design of algorithms, GA operating parameters are very probability used to obtain the new offspring. It is performed important to study and to obtain the best solution within by exchanging alleles between two selected parent reasonable computational time. chromosomes to explore new solution space. Various crossover operators found in literature are single point II. PROBLEM FORMULATION AND PROPOSED crossover, N-point crossover, arithmetic crossover, average METHODOLOGY crossover, uniform crossover, order crossover, cycle The problem has been formulated considering the data set for crossover, partially mapped crossover, shuffle crossover, experimentation as mentioned in Table: 1. Experimentation reduced surrogate crossover, flat crossover, discrete has been carried out on identical parallel machines, having crossover, heuristic crossover, statistics-based crossover, equal capability to process operations and the operation time adaptive non-uniform crossover [7] and many more. These on identical parallel machines remain the same. The crossovers have been broadly classified into the classical experiment aims to meet the objective function such as standard crossover, binary crossover, and application minimizing work-in-process material, penalty cost due to dependant crossover operators. Each crossover operator has nondelivery of the jobs within the specified time, and machine its advantages and disadvantages under various circumstances idleness cost due to non availability of processing of the job and has an impact on the performance of the genetic algorithm on the machine in a batch production environment. The [8, 9, 10, 11, 12]. fitness function necessary for the genetic algorithm is Goldberg and Lingle have proposed the partially mapped designed to meet the objective function, and coded in Matlab. crossover for traveling salesman problem [13]. It is a The input parameters considered for the experimentation are commonly used crossover operator in permutation encoded Number of parallel machines =6 chromosomes where the large solution exists. In, Partially Number of setups=3 Matched Crossover, two crossover points are selected Number of jobs/Part type=10 randomly from the parent‟s chromosomes to produce new Batch Quantity for each part type=10 offspring‟s. The crossover process happens through Objective functions: Minimum idleness of the machine and position-by-position exchange operations between the two penalty cost. crossover points in the pair of chromosomes, which gives a In the present work genetic algorithm based methodology matching selection [13, 14]. Partially Mapped Crossover (Fig: 1) is used to determine the objective function. Initially, tends to respect the absolute positions [15] and this has been randomly generated chromosomes of the population size of widely used in the scheduling process also. 20 are generated. Each chromosome is calculated for the Crossover probability is the important operator to create the fitness function. Ranking of all the chromosomes