An integrated approach for lot-sizing and storage assignment
Bibliographic record
Abstract
In this paper, we study the interaction between the lot-sizing problem and the storage assignment problem. Traditional lot-sizing problems have been studied for decades. However, only recent studies have further considered decisions related to the assignment of items to inventory locations, aiming to better model the complex reality. In our problem, the storage space is divided into several separate locations, and the inventory is assigned to the storage locations taking into account specific compatibility conditions. Relocation of inventory is also possible if needed. In addition to the traditional cost elements from the lot-sizing problem, we consider others related to holding inventory, such as fixed storage costs, handling costs, and relocation costs. We model the problem using a general mathematical model, as well as a transportation reformulation, which provides better lower bounds. We propose several heuristics to solve the problem by splitting it into smaller subproblems, which are then solved sequentially. A series of computational experiments is carried out in order to evaluate the impact of the integration between the lot-sizing and the storage assignment decisions, as well as the behavior of the different solution approaches. The results show that the proposed heuristics are highly effective in finding feasible solutions that are very close to the best solutions, while spending 97% less computational time compared to solving the full mathematical model. When compared to the relax-and-fix heuristic (benchmark), certain versions of the heuristics can find better solutions using less computational effort, underscoring the benefit of employing more specialized heuristics. Additionally, we conduct a sensitivity analysis with the aim of understanding the impact of key input parameters on the problem. The results indicate a significant influence of compatibility levels on the problem complexity. Limited item–item compatibility notably increases complexity, whereas restricted item–location compatibility reduces computational time. • Integrated lot-sizing and storage assignment problem with new cost elements. • Storage locations taking into account specific compatibility conditions. • Traditional and transportation reformulations for the problem. • Efficient heuristics to finding feasible solutions and solve the problem. • Provide insights for optimizing production planning and storage assignment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".