Lot sizing and sequencing of dependent jobs in a steel mill | |
| Author | Suriyaarachchi, Rasika Harischandra |
| Call Number | AIT Thesis no.IE-89-22 |
| Subject(s) | Steel industry and trade Economic lot size |
| Note | A thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The real-life case of multiple product single facility production system studied here has a special feature known as the sequence dependency which makes the lot sizing problem more complex and computationally intractable. In the aggregation and disaggregation approach developed to handle the situation two groups of products are formed based on the sequence dependent setup times of the selected set of products. The aggregate 0-1 mixed integer programming formulation based on the Simple Plant Location Problem is solved and then by disaggregation product wise lot sizes and sequences are determined. The solution is further improved using a heuristic lot elimination procedure by trading off between the minor setup costs and the inventory carrying costs. The improved solution is then compared with a lower bound to the exact solution derived assuming independent setup estimators. Since there are no formal setup costs accountable, an opportunity cost for the loss of profits during the setup down time is used instead. Another formulation with the profit loss as a separate cost is also tested. The latter provides a greater flexibility in dealing with the practical situation but lacks the possibility of improving the solution obtained. |
| Year | 1989 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Engineering (IE) |
| Chairperson(s) | Van Oudheusden, D.L.; |
| Examination Committee(s) | Tabucanon, Mario T.;Nagarur, Nagendra N.; |
| Scholarship Donor(s) | DAAD, Fedaral Republic of Germany; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1989 |