Production Scheduling with a Job Shop Scheduling Model

Faculty of TechnologyDepartment of MathematicsMSc Course: MSc Logistics and Supply Chain ManagementStudent number:up725080Student name: Mengjiao GuoSupervisor: Banafsheh Khosravi

The project structureProject backgroundProblem definitionMathematical ModelMethodologyComputation resultConclusion and future work

Project background

• With the continuous complex machine scheduling, an efficient machine scheduling cannot only reduce the total cost of the system, but also improve the overall performance of the system.

• Job-shop scheduling is one of the most complex problems in scheduling. In job-shop environment, there are some production stations, and every job has a specific production sequence which is not necessarily the same as the other jobs’ sequences.

• This study addresses dynamic job-shop scheduling problem to minimize completion time.

Problem definition

Job Shop Scheduling• The definition• The solution method-- Genetic Algorithm through Evolver

software Flow shop Scheduling• The definition • The different with Job shop

Mathematical Model

Methodology To solve this problem, Evolver has been selected as a method

which can deal with a huge amount variable (in this case is 100). The reason why Evolver is chosen • Evolver can solve a large problem which including “order”

problem and “variable "problem.• Evolver can use advanced heristics such as GA,Tube search to

solve the problem and get optimized solution. While Evolver also has some disadvantages:• The solution of Evolver is much affected by the initial solution.• Evolver cannot get the best solution due to the huge amount of

possible solution.

Methodology Time machine required will be available

Machine start times(releases time)

Machine completion times

Machine idle times

Methodology Set up the optimization• This problem is considering the work order about 100 tasks. The objective

is to minimize the total time required.

• In this problem, there is one order:

Computation result

I use the different way to get the best result.

model run

best solution run by changing CR

and MR

same result

02,

000

4,00

06,

000

8,00

010

,000

850

900

950

1,000

1,050

1,100

1,150

1,200Progress (All Trials)

Evolver Course VersionUniversity of Portsmouth

Computation result

Secondly, changing the population size, CR, MR directly use the model, and run a lot of times I also can get the best result which is the same with the result of auto. CR result run a lot of times to get the best result. MR resultmodel PS result

Computation result

Computation result

use 30-0.1-0.05 gets the same result with the b-best

Conclusion and Future study

The advice for the decision maker • Minimizing the makespan in a job shop is very hard problem and

solution procedures are either based on enumeration or on heuristics

• The selection of a solution

Continuing work

Thank you