关键词: 任务指派, 多工作日历, 大型工程项目, 多目标优化, 带精英策略的快速非支配排序遗传算法, 时间推算

Abstract: To solve a kind of task assignment problem of large-scale engineering project under multiple work calendars,a multi-objective optimization method was proposed.A multi-objective task assignment optimization model under multiple work calendars was established with the objective to minimize project cost and project duration.A time reckoning method based on multiple work calendars was proposed as a critical technology to solve the researched problem.A fast elitist Non-dominated Sorting Genetic Algorithm (NSGA-Ⅱ) was designed to solve the optimization model,in which an integer coding method based on contractor number was used to encode the chromosome,a two-point crossover method was used in crossover operation,and a single-point mutation method was used in mutation operation.The refusal strategy was used in the population initialization to ensure feasibility of the chromosomes,and a repair strategy was used in mutation operation to ensure feasibility of the offspring chromosomes.Project cost was obtained by summing up task cost got according to task cost array and contractor number array.Task time was obtained according to task time array and contractor number array.The earliest start time and finish time of each task were obtained based on critical path method by forward reckoning function FC.Project duration was got according to earliest start time and finish time of each task.At the end of evolution,a Pareto solution set was output to worksheet “Pareto solution set”.When the decision maker double-clicks on a Pareto solution,a scheduling matrix could be obtained by forward reckoning function FC and inverse reckoning function IC based on critical path method.The application result showed that the proposed method could effectively solve the multi-objective task assignment problem of large-scale engineering project under multiple work calendars.

Key words: task assignment, multiple work calendars, largescale engineering projects, multi-objective optimization, fast elitist non-dominated sorting genetic algorithm, time reckoning