A Genetic Algorithm for Solving Single Level Lot–Sizing Problems

2012 ◽  
Author(s):  
Nasaruddin Zenon ◽  
Ab. Rahman Ahmad ◽  
Rosmah Ali

Masalah pensaizan lot satu aras timbul apabila suatu syarikat pengeluar ingin menjanakan perancangan pengeluaran terperinci bagi produk berpandukan suatu perancangan agregat. Walaupun masalah ini telah dikaji dengan meluas, hanya pendekatan pengaturcaraan dinamik dapat menjamin penyelesaian yang minimum secara global. Maka heuristik-heuristik stokastik yang mampu melepasi minimum tempatan adalah diperlukan. Kajian ini mencadangkan kaedah algoritma genetik untuk menyelesaikan masalah-masalah pensaizan lot satu aras, serta membincangkan beberapa contoh aplikasi kaedah tersebut. Dalam pelaksanaan kaedah ini, heuristik penjanaan populasi pensaizan lot yang dapat menjanakan populasi awal digunakan untuk menyediakan kromosom. Kromosom ini digunakan sebagai input untuk algoritma genetik dengan operator-operator yang khusus bagi masalah pensaizan lot. Gabungan heuristik penjanaan populasi dengan algoritma genetik menghasilkan penumpuan yang lebih pantas dalam proses mendapatkan skim pensaizan lot yang optimum disebabkan oleh ketersauran populasi awal yang digunakan. Kata kunci: ALgorithm Genetik; Pensaizan lot The single level lot-sizing problem arises whenever a manufacturing company wishes to translate an aggregate plan for production of an end item into a detailed planning of its production. Although the cost driven problem is widely studied in the literature, only laborious dynamic programming approaches are known to guarantee global minimum. Thus, stochastically-based heuristics that have the mechanism to escape from local minimum are needed. In this paper a genetic algorithm for solving single level lot-sizing problems is proposed and the results of applying the algorithm to example problems are discussed. In our implementation, a lot-sizing population-generating heuristic is used to feed chromosomes to a genetic algorithm with operators specially designed for lot-sizing problems. The combination of the population-generating heuristic with genetic algorithm results in a faster convergence in finding the optimal lot-sizing scheme due to the guaranteed feasibility of the initial population. Key words: Genetic Algorithm; Lot-sizing

2005 ◽  
Vol 25 (3) ◽  
pp. 479-492 ◽  
Author(s):  
Franklina Maria Bragion de Toledo ◽  
André Luís Shiguemoto

In this paper, a case study is carried out concerning the lot-sizing problem involving a single item production planning in several production centers that do not present capacity constraints. Demand can be met with backlogging or not. This problem results from simplifying practical problems, such as the material requirement planning (MRP) system and also lot-sizing problems with multiple items and limited production capacity. First we propose an efficient implementation of a forward dynamic programming algorithm for problems with one single production center. Although this does not reduce its complexity, it has shown to be rather effective, according to computational tests. Next, we studied the problem with a production environment composed of several production centers. For this problem two algorithms are implemented, the first one is an extension of the dynamic programming algorithm for one production center and the second one is an efficient implementation of the first algorithm. Their efficiency are shown by computational testing of the algorithms and proposals for future research are presented.


2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Prasanna Kumar ◽  
Mervin Herbert ◽  
Srikanth Rao

This research study focuses on the optimization of multi-item multi-period procurement lot sizing problem for inventory management. Mathematical model is developed which considers different practical constraints like storage space and budget. The aim is to find optimum order quantities of the product so that total cost of inventory is minimized. The NP-hard mathematical model is solved by adopting a novel ant colony optimization approach. Due to lack of benchmark method specified in the literature to assess the performance of the above approach, another metaheuristic based program of genetic algorithm is also employed to solve the problem. The parameters of genetic algorithm model are calibrated using Taguchi method of experiments. The performance of both algorithms is compared using ANOVA analysis with the real time data collected from a valve manufacturing company. It is verified that two methods have not shown any significant difference as far as objective function value is considered. But genetic algorithm is far better than the ACO method when compared on the basis of CPU execution time.


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