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Production planning for a multi-product multi-stage system | |
Author | Das, Atash Kumar |
Call Number | AIT Thesis no. IE-88-07 |
Subject(s) | Production planning |
Note | A Thesis Submitted in Partial Fulfilment of the Requirements for t he Award of the Degree of Master of Engineering, School of Engineering and Technology |
Publisher | Asian Institute of Technology |
Series Statement | Thesis ; no. IE-88-07 |
Abstract | This study was concerned with the production planning problem of a multi- product multi- stage system (an edible oil refinery). A two phase planning scheme has been considered for the problem. In the first phase of this study similar products have been aggregated into some major product categories and the demands for each of these categories were forecasted for an entire seasonal cycle (a year). Three exponentially weighted time series smoothing models were employed for the purpose and the smoothing constants were optimized. The best forecasts corresponding to the least sum of square error were chosen and used subsequently. In the second phase a modified LP model was employed to determine the optimal production plan for each product of each facility and in each period that would meet all the demands and satisfy the capacity and storage restrictions throughout the entire planning horizon . To permit a detailed consideration of all products (which is essential for the system), a hierarchical approach has been adopted. In the aggregate analysis the planning horizon has been partitioned into four equal periods and for each period the cost- optimal production and inventory decisions subject to the aggregate restrictions for capacity and storage were determined. In the succeeding step these decisions for the first period were disaggregated to obtain biweekly production plans for each facility. Since the forecasts are likely to vary from the actual realizations of demand (because of the random component in the time series), safety measures have been incorporated in the models to ensure that all demands can be met. This measure assumes that in no periods the actual demand of a product will exceed the corresponding forecast by an amount more than its next month's demand and in each period thus carries an inventory equal to the product's next month's forecasted demand. Finally a rolling horizon model- implementation scheme has been suggested that would allow periodic application of the aggregate and the disaggregate models. |
Year | 1988 |
Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. IE-88-07 |
Type | Thesis |
School | School of Engineering and Technology |
Department | Other Field of Studies (No Department) |
Academic Program/FoS | Industrial Engineering (IE) |
Chairperson(s) | Fujiwara, Okitsugu ; |
Examination Committee(s) | Tabucanon, Mario T. ;Awate, Prakash G. ; |
Scholarship Donor(s) | DAAD, West Germany; |
Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1988 |