共查询到17条相似文献,搜索用时 78 毫秒
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一种多阶段供应商选择的混合整数规划模型 总被引:4,自引:0,他引:4
在建立供应链合作伙伴关系中,供应商的选择是供应链管理的一项重要内容.在现有文献的基础上对供应商的选择模型进行了改进,建立了集成单阶段与多阶段供应商选择的混合整数规划模型:既可以选择单阶段供应商,也可选择多阶段供应商即供应商的供应商的供应商等等.在模型中考虑了每个潜在供应商的能力约束,以供应商在产品价格、质量、配送水平等三个方面引起总的客户不满意度最小化作为选优的依据. 相似文献
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针对太阳能小屋并网光伏阵列安装布局优化问题,构造多目标混合整数规划模型进行求解;引入0-1决策变量对电池组件的选取方案进行描述;通过电池组件的布局规则约束,建立以年光伏发电总量最大、单位发电量的费用最小的多目标混合整数规划模型;选取各目标优先级,将多目标规划模型转化为单目标最优化问题;利用Matlab软件,采用Monte Carlo计算机模拟算法,得到太阳能小屋各外表面光伏阵列优化布局方案;并计算得到在给定数据下,在贴附安装时小屋一年发电量为21381.09kWh,35年总发电量为673500kWh,经济效益为336750元,总投入资金为199610元,得到投资回报年限约为10年。 相似文献
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非线性混合整数规划问题的改进差分进化算法 总被引:2,自引:0,他引:2
针对非线性混合整数规划问题,本文采用非固定多段映射罚函数法处理约束条件、用混合整数编码技术处理连续变量和整数变量,并在基本差分进化算法中加入一种新型的凸组合变异算子和一种指数递增交叉算子,由此构造出了一种求解非线性混合整数规划问题的改进差分进化算法。实验表明,所提出的算法全局收敛速度快,精度高,鲁棒性强。 相似文献
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目的 针对工厂产品的托盘打包及装箱问题,提出一种优化产品在托盘上的布局以及托盘与产品整体在集装箱中的布局方法,以最大化集装箱的空间利用。方法 在满足现实约束的条件下,以最大化产品装载体积为目标建立混合整数规划模型。考虑问题的复杂性,本文将所研究的问题分解为2个子问题,并建立两阶段装载模型进行求解。第1阶段,建立二维集装箱装载模型,确定多种托盘类型在集装箱底面的平面布局;第2阶段,建立三维托盘装载模型,确定产品在托盘上的立体布局。鉴于精确求解该问题耗时较大,本文针对2个子问题设计两阶段启发式算法求解。为验证模型及算法的有效性,采用2组不同规模大小的算例进行测试。结果 算例结果表明,在小、大2种规模算例中,装载率平均差值分别为0和-0.5%,计算时间相差较大,本文提出的模型及算法在合理的时间内获得了最优解或近似最优解。结论 本研究能够为工厂产品的托盘打包及装箱提供快速高效的解决方案。 相似文献
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本文讨论了上层决策变量为整数变量、下层决策变量为连续变量的混合整数双层线性规划问题,利用其可行解均落在约束域边界上的性质,提出了一种求解混合整数双层线性规划全局最优解的算法,并举例说明了算法的执行过程。 相似文献
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通过膜元件参数对系统产水含盐量的相关分析得出了相应的系统灵敏度参数,进而形成了反渗透系统膜元件优化排列的0-1整数规划模型.通过对整数规划的求解与膜元件全排列的系统模拟计算,验证了膜元件优化排列的数值优势与统计优势. 相似文献
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针对有装配线最小批量要求且供应商交货数量随机条件下的多物料订货量分配问题,以订货成本、采购成本、库存持有成本和拖期成本组成的总成本最小为优化目标,构建了混合整数随机规划模型;使用离散粒子群优化算法对模型进行求解,通过两组算例将粒子群优化算法与遗传算法和枚举算法进行了对比分析,算例结果验证了离散粒子群优化算法解决该问题的可行性和有效性。最后,通过一组实例分析了不同单位拖期成本和单位库存成本情形下的订货量分配方案以及单位拖期成本/单位库存成本这一比例对总成本的影响。实例结果表明,物料的订货量分配方案与单位拖期成本/单位库存成本有关,且总成本与该比例呈线性相关关系。 相似文献
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We develop a two-stage stochastic integer programming model for the simultaneous optimization of power production and day-ahead power trading in a hydro-thermal system. The model rests on mixed-integer linear formulations for the unit commitment problem and for the price clearing mechanism at the power exchange. Foreign bids enter as random components into the model. We solve the stochastic integer program by a decomposition method combining Lagrangian relaxation of nonanticipativity with branch-and-bound in the spirit of global optimization. Finally, we report some first computational experiences. 相似文献
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In the present paper a cutting plane approach to solve mixed-integer non-linear programming (MINLP) problems, containing pseudo-convex functions, is given. It is shown how valid cutting planes for pseudo convex functions can be obtained and, furthermore, it is shown how a class of non-convex MINLP problems with a pseudo-convex objective function and pseudo-convex constraints, can be solved to global optimality with the considered cutting plane technique. Finally the numerical efficiency of the procedure, when solving some example problems, is illustrated. 相似文献
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As a result of an increasingly competitive market, companies must find ways to organize their activities regarding their economic outcome. An important feature in this context involves transportation operations, usually considered one of the major bottlenecks in the production chain. While delays imply loss of time and lack of resources, deliveries ahead of the deadlines may cause excess of inventories. Therefore, every company must pursue efficient transportation schedules within their operational planning. This work addresses short-term crude oil scheduling problems in a distribution complex that contains ports, refineries and a pipeline infrastructure capable of transferring oil from the former to the latter. The ports comprise piers, which receive vessels for discharging, storage tanks and a network that connects each other. The refineries have their own storage infrastructure, modeled as a large storage unit, along with crude distillation units, considered as constant level consumers. The problem involves a number of other issues, including intermediate storage, settling tasks and allocation of crude oil by its qualitative characteristics. A decomposition strategy based on large-scale mixed-integer linear programming (MILP) continuous-time models is developed. First, an MILP model that considers an aggregate representation for the pipeline and intermediate storage infrastructure is proposed. Decision variables involve the assignment of oil tankers to piers as well as tanker unloading and pipeline loading operations. The solution of this model provides the initial conditions for MILP models that represent the pipeline and intermediate storage infrastructure at a detailed level. Algorithms based on the LP-based branch-and-bound method are employed. Results from a port scenario of 13 tankers, 4 piers, 14 crude types, 18 storage tanks and 2 pipelines were obtained in approximately 90 minutes from an MILP problem containing 1996 continuous variables, 1039 binary variables and 7203 constraints. 相似文献