job shop 111
TRANSCRIPT
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