| 1. |
|
|
| 2. |
|
|
| 3. |
- Ari, E. Aysen, et al.
(författare)
-
Disaggregation under uncertainty in hierarchical production planning
- 1988
-
Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217 .- 1872-6860. ; 35:2, s. 182-186
-
Tidskriftsartikel (refereegranskat)abstract
- This study deals with a hierarchical planning system that is used for planning of a single-stage manufacturing system. We consider two decision levels, aggregate and detailed planning, and formulate a model for evaluation of aggregate plans and optimal disaggregation in case of independent stochastic demand. It is shown how the optimal solution can be obtained with the aid of a dynamic programming algorithm. Furthermore, we give conditions that will guarantee optimality of a simple intuitive disaggregation rule
|
|
| 4. |
- Axsäter, Sven
(författare)
-
A Capacity Constrained Production-Inventory System with Stochastic Demand and Production Times
- 2010
-
Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 48:20, s. 6203-6209
-
Tidskriftsartikel (refereegranskat)abstract
- This paper considers a simple model of a capacity constrained production-inventory system with Poisson demand. The system is controlled by an S policy. The production time for a unit is modelled as a gamma distributed stochastic variable. Using M/G/1 queuing theory it is very easy to evaluate holding and backorder costs and optimise the ordering policy. The suggested model may be useful when evaluating investments in production.
|
|
| 5. |
- Axsäter, Sven, et al.
(författare)
-
A distribution inventory model with transshipments from a support warehouse
- 2013
-
Ingår i: IIE Transactions. - 0740-817X. ; 45:3, s. 309-322
-
Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedThis article considers a distribution inventory system consisting of N retailers and a regional support warehouse, all being replenished from a central warehouse/outside supplier. For the case where stock-outs occur, the retailers receive transshipments from the support warehouse at an extra cost. A model is presented for cost evaluation and optimization of the reorder points in the system under fill rate constraints. The solution method is designed to handle large real-life systems and is fast enough to be directly implemented in practice. A numerical study illustrates that (i) the model renders near-optimal solutions; (ii) the value of using a support warehouse can be significant even for large transshipment costs; and (iii) significant cost savings can be obtained using the proposed model. Using real data for a sample of 50 representative products, the proposed model reduces the expected holding and transshipment costs by 29% while still meeting target fill rates. [Supplemental materials are available for this article. Go to the publisher's online edition of IIE Transactions to view the supplemental file.]
|
|
| 6. |
|
|
| 7. |
- Axsäter, Sven
(författare)
-
A Heuristic for Triggering Emergency Orders in an Inventory System
- 2007
-
Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217. ; 176:2, s. 880-891
-
Tidskriftsartikel (refereegranskat)abstract
- This paper considers a single-echelon inventory system with a warehouse facing compound Poisson customer demand. Normally the warehouse replenishes from an outside supplier according to a continuous review reorder point policy. However, it is also possible to use emergency orders. Such orders incur additional costs but have a much shorter lead time. We consider standard holding and backorder costs as well as ordering costs. A heuristic decision rule for triggering emergency orders is suggested. The decision rule minimizes the expected costs under the assumption that there is only a single possibility for an emergency replenishment, but the rule is used repeatedly as a heuristic. Given a certain reorder point policy for normal replenishments, our decision rule will always reduce the expected costs. A simulation study illustrates that the suggested technique performs well under different conditions.
|
|
| 8. |
|
|
| 9. |
- Axsäter, Sven
(författare)
-
A New Decision Rule for Lateral Transshipments in Inventory Systems
- 2003
-
Ingår i: Management Science. - : Institute for Operations Research and the Management Sciences (INFORMS). - 0025-1909 .- 1526-5501. ; 49:9, s. 1168-1179
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with a single-echelon inventory system consisting of a number of parallel local warehouses facing compound Poisson demand. There are standard holding and backorder costs as well as ordering costs at all warehouses. Normally, the warehouses replenish from an outside supplier. However, lateral transshipments between the warehouses are also possible. Such transshipments take no time but incur additional costs. When a demand occurs at a warehouse, the question is whether the whole demand or part of it should be covered by a lateral transshipment from another warehouse. Given a set of alternative decisions, our decision rule minimizes the expected costs under the assumption that no further transshipments will take place. This rule is then used repeatedly as a heuristic. A simulation study illustrates how the suggested technique performs under different conditions.
|
|
| 10. |
|
|
