Study On The Scheduling Problems With Limited Availability Of Machines

Machine scheduling problem is an important research topic in the field of production scheduling area.In recent years,it has been widely concerned by many fields such as management science and operations research.In classical scheduling models,it is usually assumed that the machine can work all the time throughout the whole scheduling period.However,in actual production,the machine may not be able to be used immediately because of sudden breakdown or special maintenance.This phenomenon is common in manufacturing enterprises.As the cold chain enterprises have higher requirements for operating environment,such as the operation of refrigeration equipment and specific processing temperature,it is particularly obvious and more important in cold chain enterprises.Therefore,it is of great theoretical and practical significance to consider such available constraints in resource scheduling problems.On the basis of summarizing the relevant literature in this field,this paper researches the scheduling problem with machine available constraints,and two cases of general scheduling environment and cold chain scheduling environment are analyzed respectively.In the general scheduling environment,it is assumed that the raw materials will not be deteriorated.The aim is to minimize the makespan,subject to the available constraint of machine.Uniform parallel machine scheduling problem is considered,they have different speeds and available time.We analyze the problem first of all,and an upper bound for FFD algorithm of this problem is presented and proved,then four properties of inserting jobs are proposed.Based on these,we put forward a heuristic algorithm.Finally,the validity of the algorithm is verified through a large number of random data experiments.In the cold chain scheduling environment,not only the constraint of the machine can be considered,but also the restriction of the material deterioration.For cold chain business,reducing the cost of deterioration is very important.Therefore,the objective is set to minimize the total deteriorating cost.When the machine is unavailable at the beginning of the scheduling period,a dynamic programming algorithm is constructed.For the case that machine unavailable occurs during the period,the corresponding heuristic algorithms and simulated annealing algorithms are designed.The experimental results show that the simulated annealing algorithm can obtain satisfactory solutions of higher quality.