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为了减少板式家具企业封边工序过长的准备时间以及提高原材料的开料利用率,满足企业快速组批的需求,本文研究板式家具的订单组批问题,并提出一个组批优化的方法。在对组批问题进行定义和数学描述的基础上,建立了一个双目标问题的数学模型,通过序贯优化分析如何求解双目标问题,设计出一种组合调度规则的启发式算法。为了验证算法和评估调度规则的性能,设计了该类问题的算例生成方法,并将本文的方法与另外构造的10种规则算法应用到生成的算例上,进行仿真调度,最后与精确解法作比较。仿真调度的结果显示基于板块颜色与板块厚度的调度规则可以有效地降低封边工序的准备时间,提高原料利用率。 相似文献
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目的 采用直发包装SKU归并优化方法,通过减少最小存货单位(Stock Keeping Unit,SKU)的种类,来达到节省物料成本的目的。方法 综合运用k-means聚类分析和组合优化理论,建立直发包装SKU归并模型,并设计基于非均匀变异算子的遗传算法求解方法。以随机生成SKU尺寸信息及其对应的直发包装订购数量的测试数据集为例,通过对比归并前后的SKU种类数和物料成本来验证优化方法的有效性和可行性。结果 优化后,直发包装SKU归并方案中SKU种类的平均降低率为33.13%,归并可使物料成本平均下降2.84%。结论 研究成果可丰富直发包装领域的相关研究,对优化供应链结构,促进包装系列化、智能化发展具有指导意义。 相似文献
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物流活动的空载率居高不下源于路径规划不合理及企业间缺少合作,共同配送是降低空载损失的有效模式,但非集中式共同配送下物流企业可能基于被分派的订单选择自身成本最小的配送路径,从而导致共同配送联盟的空载损失变大。本文研究考虑空载损失的非集中式共同配送订单分派及路径优化,首先提出空载损失定义,权衡整个配送过程的成本最小和空载损失最小两个目标,基于非集中式共同配送的特征设计订单分派策略,进而建立订单分派及路径优化模型。设计了基于ε约束法的精确算法、改进的MOPSO (multiple objective particle swarm optimization)算法、多项式时间快速算法进行求解,并结合算例验证算法的有效性。数值分析结果表明,即使物流企业均追求自身成本最小化,提出的订单分派策略也可得到与全局优化相近的结果。 相似文献
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目的 针对面向仓储物流环境下多型号多批量产品的订单包装问题,提出一种预制物流箱规格优化模型及算法。方法 对产品订单建立订单分包规则,确定分包方案,以订单包装材料总成本最小为优化目标建立物流箱规格优化模型。针对该模型提出一种改进模拟退火算法,通过贪婪策略求解最优分包方案,降低模型计算复杂度,设计一种新型解更新算子,以提高算法寻优能力,设计一种自适应步长策略,以平衡算法前期全局搜索与后期局部搜索的能力。结果 通过实例证明,文中提出的算法相较于其他算法,具有更强的求解能力,与实例企业仓储包装现状相比,同批订单降低了17%的包装材料成本。结论 该方法可用于解决产品种类多、尺寸差异大、动态更新等应用场景下的系列运输包装纸箱规格优化问题,为企业物流运输管理提供了一种有效的包装优化思路和解决方法。 相似文献
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针对多订单情况下多产品生产计划安排研究存在不足,提出了一种新的基于订单的计划排期多目标优化模型,目标包括利润最大化与均衡生产,通过各计划期之间产量安排对各资源消耗的偏差最小化来实现均衡生产.模型存在非线性多目标,实现时采用了遗传算法,通过Sheffield GATBX利用MATLAB编程实现. 相似文献
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针对柔性化钣金产线加工订单呈现离散化特征所导致的人工排程不能满足需求的问题,在订单按时交货的基础上以最小化综合成本及最低综合设备损耗为目标,基于Drools规则约束引擎,研究适用于柔性化钣金产线的快速寻优排程方法.以钣金生产为例,分析排程规划问题的求解过程,通过分析多目标求解的问题提出结合Drools规则引擎的求解方法... 相似文献
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通过对“以德治国”提出的重要意义 ,“以德治国”是“依法治国”的重要补充 ,以及“德治”和“法治”的关系等几方面进行的讨论 ,提出为进一步巩固党的领导 ,实施“以德治国”中官德修养的主要途径和工作方法 相似文献
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In this paper, the control problem of multiple-load automated guided vehicles (AGVs) is studied. A control process that identifies four problems faced by multiple-load AGVs is proposed. The first problem is the task-determination problem, in which a multiple-load AGV determines whether its next task is a pickup task or a delivery task. The second problem is the delivery-dispatching problem, in which a multiple-load AGV determines which delivery point it should visit next if its next task is a delivery task. The third problem is the pickup-dispatching problem, in which a multiple-load AGV determines which pickup point it should visit next if its next task is a pickup task. Finally, the fourth problem is the load-selection problem, which requires a multiple-load AGV to determine which load it should pick up from the output queue of a pickup point. This paper focuses on the first and second problems. Different task-determination rules and delivery-dispatching rules are proposed for these two problems. For the problems that are not the main focus of this study, rules found in the literature or real systems are adopted in this study. The objective of this study is twofold. First, we need to understand how well the proposed rules will perform in different performance measures, e.g. the system's throughput and the mean lateness of parts. Second, we need to understand the mutual effects that different types of rules have on each other, so that the best combination of rules can be identified. Computer simulations were conducted to test the performance of the proposed rules. It is hoped the knowledge learned from this study can be beneficial to real multiple-load AGV systems similar to the one studied here. 相似文献
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Temperature and frequency dependence of a.c. conductivity have been studied in glassy Se70Te30−xSbx (4 ≤ x ≤ 10) alloys. The observation of Further Meyer-Neldel rule in case of a.c. conductivity is reported. The observation of the correlation between Meyer-Neldel pre-factor σ00 and Meyer-Neldel energy is explained by multiple excitations stimulated by optical phonon energy as described by Yelon and Movaghar. 相似文献
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P. Karvan A. Varvani‐Farahani 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(1):295-306
The present study intends to characterize ratcheting response of several steel alloys subject to asymmetric loading cycles through coupling the Ahmadzadeh‐Varvani kinematic hardening rule with isotropic hardening rules of Lee and Zavrel, Chaboche, and Kang. The Ahmadzadeh‐Varvani kinematic hardening rule was developed to address ratcheting progress over asymmetric stress cycles with relatively a simple framework and less number of coefficients. Inclusion of isotropic hardening rules to the framework improved ratcheting response of materials mainly over the first stage of ratcheting. Lee and Zavrel model (ISO‐I) developed an exponential function to account for accumulated plastic strain as yield surface is expanded over stage I and early stage II of ratcheting. Isotropic models by Chaboche (ISO‐II) and Kang (ISO‐III) encountered yield surface evolution in the framework by introducing an internal variable that takes into account the prior maximum plastic strain range. The choice of isotropic hardening model coupled to the kinematic hardening model is highly influenced by material softening/hardening response. 相似文献
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Numerical computations are presented confirming the possible breakdown of the Cauchy-Born rule for an infinite planar square lattice whose vertices are occupied by interacting particles, in agreement with the theoretical predictions of Friesecke and Theil (2002). Energy minimization yields solution branches exhibiting a non-zero deviatoric inner displacement for shearing and extensional deformation. A statically square lattice can become unstable when subjected to sufficiently large deformation. Numerical solutions of a boundary-value problem illustrate the development of irregular lattice configurations under supercritical conditions. 相似文献
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为了建立材料和价值创造的良性循环,在未来必须考虑到全部产品及其各部件。这里的目标是使产品在循环过程中得到再生利用。当然,在这设计制造产品时就要求具备多方面的前提条件。适应产品再生利用设计的主要问题在于对未来要求的可预见性,这要求考虑到今后创新的实施。在此,以机床开发为例,提出一些相应的规则和说明,这些规则互相制约,并且对各类产品类型产生效应。 相似文献
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本文阐述了不同储存形态玉米水分的变化幅度。既包装玉米大于囤积玉米:囤积大于散装玉米:穗藏大于粒藏玉米:露天储存玉米大于仓内储藏玉米。无论哪种储存形态的玉米,其水分的变化幅度都遵循一个规律:上层玉米(接触空气多)水分的变化,一般大于下层,了解这一规律对安全储存玉米具有实际指导意义。 相似文献
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森林火灾发生规律、引发因素与预防措施 总被引:1,自引:0,他引:1
林顺根 《中国新技术新产品》2011,(3):354-355
森林火灾突发性强,危害性大,烧毁林木及林下植物资源,引起水土流失,危害整个森林生态系统,破坏森林生态系统的平衡和人类生存环境。破坏森林生态生态系统平衡,危害野生动物栖息环境,给人类的经济建设造成巨大损失,甚至还威胁到人民生命财产的安全,其危害程度居森林三大自然灾害之首。本文作者在对贵州省黔东南自治州近十年来森林火灾发生规律、特点,起因分析统计的基础上,提出综合预防措施。 相似文献