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121.
T. G. Deepak A. Krishnamoorthy Viswanath C. Narayanan K. Vineetha 《Annals of Operations Research》2008,160(1):191-213
An inventory system with two parallel service facilities is considered. A certain number of customers are transferred from
longer to shorter queue whenever their difference reaches a prescribed quantity. Along with this customer transfer, a certain
quantity of inventory is also transferred, depending on availability. Further, if one of the queues has customers, but has
no inventoried items whereas the other has at least one inventoried item to spare, then exactly one item is taken to the former
and service begins thereby enhancing the efficiency of the system. Stability of the system is analysed. Several performance
measures that helps in efficient design of such systems, are computed. Some numerical results are provided. 相似文献
122.
李金铠 《数学的实践与认识》2008,38(13)
运用最优控制理论和数理经济学方法研究了供应链管理时代下广泛存在的双向替代产品的最优库存问题,建立了利润最大化前提下的双向替代品的库存模型,证明了该问题解的存在性,并给出了求解最优订货量的方法步骤,可为实施有效的库存管理、降低企业的物流成本提供借鉴. 相似文献
123.
A continuous revies (s, S) inventory system with renewal demand in which one item is put into operation as an exhibiting piece is analyzed. The lifetime of any operating unit has Erlangian distribution, and on failure is replaced by another one from the stock and the failed item is disposed of. Replenishment of stock is instantaneous. The transient and stationary values of inventory level distribution and the mean reorder rate are obtained using the techniques of semi-regenerative processes. Decision rules for optimums andS that minimize the long-run expected cost rate are derived. The solution for a dual model with the distribution of lifetimes and inter-demand times interchanged is also given. 相似文献
124.
Leonard Fortuin 《European Journal of Operational Research》1984,17(2):266-270
The expected demand for service parts is easy to calculate, as long as their failure rate is constant. Certain service parts, however, have a failure rate that is time-dependent. If their failure times have a Weibull distribution, the simple calculation methods brake down and much computational effort is required to determine the expected demand exactly. This paper presents a simple approximation of the expected demand that compares well with exact answers. 相似文献
125.
F. Kabbaj J. L. Menaldi E. Rofman 《Journal of Optimization Theory and Applications》1990,65(3):447-483
We discuss stochastic, continuous-time models of serial multilevel production/inventory systems using quasi-variational inequalities. The value functions are characterized as maximum solutions of suitable equivalent problems. Then, we show how to construct optimal centralized policies and, if possible, decentralized policies. Finally, we present some numerical examples for the deterministic case.The work of the second author was supported by the National Science Foundation under Grant No. DMS-87-02236. 相似文献
126.
F. Marcotorchino 《商业与工业应用随机模型》1987,3(2):73-91
In their article, entitled ‘Group technology in production management, the short horizon planning level’, H. Garcia and J. M. Proth have stated the following problem: starting from a (0, 1) binary matrix of size (N x M), how to divide into independent subsets the rows of this matrix simultaneously with a one-to-one corresponding partition of the columns, maximizing the presence of 1s in the intersecting blocks with a joint minimization of the presence of 0s outside of these blocks. The authors have proposed an efficient and very fast heuristic algorithm in comparison with the existing methods of a fast-growing literature on the subject. The only drawback of this algorithm is its dependence on the initial partition. In this paper, we try to improve this algorithm slightly, first in rewriting the objective function in a linear form and secondly in giving computational improvements related to this linear formulation. 相似文献
127.
库存信息在整个企业信息系统中起着纽带作用 ,为了对企业的整体运作进行有效的监控和管理 ,采用规范化的方法建立库存系统模型是核心 .本文针对工业企业库存控制问题 ,结合遗传算法的特点 ,提出了一种新型的探索策略 .仿真结果表明 ,该方法求解的最优控制策略同弱化条件后用其他方法求解所得的最优策略非常逼近 .该方法不仅提高了求解全局最优解的可靠性 ,而且减少了迭代次数 ,提高了计算效率 相似文献
128.
在考虑预防性维修周期和提前期不确定的条件下,分别研究备件存储与其相关的维修费用、缺货费用、库存费用以及订购费用等四种费用之间的关系,明确了备件存储量对各项费用的影响.以各项费用总和最小化为目标,构建了提前期不确定条件下的预防性维修备件存储模型.通过备件存储模型的构建,对备件存储过程中的各项成本进行分析,以期对备件库存策略的确定给出一种解决方案. 相似文献
129.
Optimal inventory and insurance decisions for a supply chain financing system with downside risk control 下载免费PDF全文
This research considers a supply chain financing system consisting of a capital‐constrained retailer, a supplier and a risk‐averse bank. The retailer may be subject to credit limit because of the bank's downside risk control, and hence, credit insurance should be needed to enhance his financing ability. This paper develops a mathematical optimization model by incorporating insurance policy into the well‐known newsvendor financing model. The optimal inventory and insurance decisions under different scenarios, that is, no insurance, insurance with symmetric information and insurance with asymmetric information, are derived. This work also discusses how the retailer's capital level, the bank's risk aversion, and the insurer's loading factor affect the optimal inventory and insurance decisions. The results show that the retailer will use credit insurance if he is sufficiently capital‐constrained or the insurer's risk loading factor is low enough. Moreover, credit insurance can bring Pareto improvement to the supply chain financing system, which verifies the prevalence of credit insurance in practice. Several numerical experiments are presented to examine the sensitivities of key parameters. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
130.
Julio F. Mata-Segreda 《Isotopes in environmental and health studies》2013,49(1):17-21
Ethyl formate undergoes spontaneous hydrolysis through two parallel mechanistic pathways: water catalysis and specific hydrogen-ion catalysis. The proton inventory of the water reaction at 37.0 °C was determined from the overall conversion curves, in H2O/D2O mixtures of deuterium atom fraction n, resulting in k 1(n)=(2.1±0.1)×10?5 s?1 (1?n+0.42 n) (1?n+0.83 n)2, in agreement with the results of six other cases of carboxylic acid derivatives. This result contributes to the validation of the accuracy of the proton inventory technique. 相似文献