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在汽车冲压生产排产优化国内外相关研究的基础上,将已有研究问题分为三类:汽车冲压生产批量计划问题、汽车冲压生产调度问题和汽车冲压生产排产集成优化问题。对这三类问题分别进行了研究,并结合实际问题,提出了汽车冲压生产排产优化的未来发展方向。 相似文献
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石油化工属于流程工业的范畴,其生产过程与离散制造业的生产过程有本质上的不同,需要不同的建模和优化方法,以及生产计划和调度的技术。经研究后,发现基于仿真的优化适合解决此问题。鉴于炼油生产问题的不确定性和复杂性,本文采用面向对象分析的方法,对炼油生产的一次加工过程进行建模分析,在此基础上采用eM—plant建立起该问题的仿真模型。通过仿真实验可以辅助手工的排产,也可以判断排产算法得到的计划是否可行,如计划不可行时提示出错的相关信息,为排产算法的修正提供帮助。 相似文献
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针对出口型轴承企业面临的产品种类多、批量小、交付时间短、成本压力大等问题,结合ERP管理系统,给出了ERP高级排产系统对问题的详细解决方案。该系统可帮助企业降低库存量,缩短生产提前期,合理利用生产资源,降低生产成本,提高生产效率。 相似文献
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V. Kayvanfar M. Zandieh 《The International Journal of Advanced Manufacturing Technology》2012,62(5-8):759-773
This paper addresses an economic lot scheduling problem (ELSP) for manufacturing environments regarding slack costs and deteriorating items using the extended basic period approach under Power-of-Two (PoT) policy. The purpose of this research is to determine an optimal batch size for a product and minimizing total related costs to such a problem. The cost function consists of three components, namely, setup cost, holding cost includes deteriorating factor, and slack cost. The ELSP is concerned with the scheduling decision of n items and lot sizing. Avoiding schedule interference is the main problem in ELSP. The used PoT policy ensures that the replenishment cycle of each item to be integer and this task reduces potential schedule interferences. Since the ELSP is shown as an NP-hard problem, an imperialist competitive algorithm is employed to provide good solutions within reasonable computational times. Computational results show that the proposed approach can efficiently solve such complicated problems. 相似文献
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Recently, an expression has been developed to take into account the complex dependence of the fine structure in core-level electron energy-loss spectroscopy (EELS) in anisotropic materials on specimen orientation and spectral collection conditions [Y. Sun, J. Yuan, Phys. Rev. B 71 (2005) 125109]. One application of this expression is the development of a phenomenological theory of magic-angle electron energy-loss spectroscopy (MAEELS), which can be used to extract the isotropically averaged spectral information for materials with arbitrary anisotropy. Here we use this expression to extract not only the isotropically averaged spectral information, but also the anisotropic spectral components, without the restriction of MAEELS. The application is based on a multivariate statistical analysis of core-level EELS for anisotropic materials. To demonstrate the applicability of this approach, we have conducted a study on a set of carbon K-edge spectra of multi-wall carbon nanotube (MWCNT) acquired with energy-loss spectroscopic profiling (ELSP) technique and successfully extracted both the averaged and dichroic spectral components of the wrapped graphite-like sheets. Our result shows that this can be a practical alternative to MAEELS for the study of electronic structure of anisotropic materials, in particular for those nanostructures made of layered materials. 相似文献
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具有项目投标价格和完工时间因素的带工期约束的伙伴选择问题是企业动态联盟的基本问题,证明了该问题是NP完全问题。为设计求解该问题的分支定界算法,建立了非线性整数规划模型。证明了模型中目标函数和约束函数的单调性,并利用单调性给出了判断问题无解和问题最优解已知的条件,构造了收缩求解区域的二分法。实验表明,基于这些结果所构造的分支定界算法是有效的。 相似文献
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关键工序的作业排序问题是生产车间的一项重要内容,讨论了把n个带工艺约束的任务安排给m台设备加工,使得总加工时间最短的一类排序问题。在建立了该问题的数学模型的基础上,巧妙地把这个排序问题转化为指派问题,并采用匈牙利算法对该问题进行了求解。实例证明,建立的数学模型和提出的问题转换方法便于理解,求解快速有效。 相似文献
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基于模型修正技术及模态柔度曲率差方法提出了一种解决大型复杂结构损伤识别问题的两步法。首先运用基于模型修正的损伤识别方法进行模糊识别,通过建立带约束边界非线性最小二乘目标函数,极小化结构实测模态与解析模态之间的误差,将损伤识别问题转化为优化问题,并采用信赖域方法求解该优化问题,识别出损伤所属单元组。然后运用模态柔度曲率差方法,对损伤进行精确定位。对某导弹发射台骨架的数值仿真及试验研究结果表明,该损伤识别两步法识别效果较为理想,为解决大型复杂结构的损伤识别问题提供了新思路。 相似文献
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基于区间牛顿法的点到参数曲线最小距离的计算方法 总被引:1,自引:0,他引:1
求解点到参数曲线的最小距离常常用一般的搜索算法。针对搜索算法的稳定性和有效性通常不高的问题,基于参数曲线的几何特性,将求最小距离转化为方程求解问题,应用了区间牛顿法来求解方程。研究结果表明,区间牛顿法是一个全局收敛的方程求根算法,具有较高的稳定性。 相似文献
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In this paper a general method for describing multirigid body systems is represented, which uses a special notation of open loop kinematical chains and three types of elementary constraints. The dynamic model is automatically generated in a numerical way. It is proposed to treat the natural (physical) or artificial constraints in a unified sense and include both in the generalized dynamic problem. The generalized dynamic problem is formulated as an initial-value problem of a nonlinear system of algebraic differential equations and is solved by a multistep technique combined with a Newton method.
This method was successfully tested in the software-package CAE-IR. Some applications of the elementary constraints are represented. 相似文献
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