首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
JIT系统下的单机提前/拖期调度问题   总被引:2,自引:1,他引:1  
分别研究了交货期及交货期窗口下的单机调度问题,目标是寻找一个最优调度极小化提前/拖期任务数。假设如何任务在交货期或交货期窗口内完工,则不受处罚;否则,就要受到一个固定的提前/拖期惩罚;提出了在交货期及交货期窗口下的寻找最优调度的多项式算法,并以两个实例说明了算法。  相似文献   

2.
研究了网络化集成制造模式下的JOB-SHOP调度问题,即各任务有具体交货期约束的提前/拖期不同惩罚系数的复杂调度问题;提出了一种新的编码方案和相应的交叉算子,进而提出混合遗传算法;成功解决了上述问题,即找到一个最优调度,使在交货期窗口外完工的任务所受到的提前/拖期惩罚的总和最小.该算法解码复杂度低、通用性强、罗拔性强,最后用算例说明了算法的有效性并指出了工件车间调度问题中尚待解决的问题.  相似文献   

3.
针对退役产品拆解工艺与物流存在的不确定性,提出一种逆向生产和物流集成调度拆解车间优化方法.分析退役产品拆解车间作业过程中生产与物流相互影响因素,以优化逆向生产与物流过程中的最大完工时长和提前/拖期成本为目标构建车间多目标调度模型.基于物流路径决策,设计一种带基因修复的变异算子改进NSGA-Ⅱ算法的变异准确性,提升算法的求解有效性.以某公司的手机拆解线为例,分析多尺寸的生产、物流算例.结果表明,随着自适应引导车数量的增加,大、小尺寸算例的拖期成本分别减少了57.1%和58.3%,验证了模型的有效性.  相似文献   

4.
研究了具有不同交货期窗口的Flowshop提前/拖期调度问题,并考虑处理时间的不确定性以及存储时间的有限性,在模糊规划理论基础上,建立了带有提前/拖期的存储时间有限型Flowshop的调度模型,通过中间值最大隶属度算法,将原有的模糊调度模型转化为清晰的调度模型,并应用了遗传算法进行优化求解。仿真实验验证了算法的有效性。  相似文献   

5.
随着JIT生产管理技术的出现和发展,考虑工件提前拖期费用的生产调度问题已经成为人们研究的热点领域.本文对蚁群算法进行了有效的改进,在状态转移规则中引入了有限时段滚动优化的特点,并应用在解决带交货期窗口的提前/拖期Job Shop问题上,仿真实验验证了改进算法的有效性,给出了相应问题的最优值的演化曲线图与Gantt排序图.  相似文献   

6.
本文考虑了一个包含工件生产和工件送货的单机调度问题。目标是寻找所有工件的公共交货期和每个工件的送货时间使得工件所受到惩罚(提前/拖后惩罚,送货费用等)的值最小。完成的工件按照批次进行送货,所有在公共交货期前完工的工件在最优交货期时间一起交付,对批次送货没有量的约束。本文确定了最优公共交货期,并给出了相应的排序。  相似文献   

7.
用GA算法解不确定条件下Job Shop的提前/拖期调度问题   总被引:1,自引:1,他引:1  
研究了具有公共交货期窗口的 Job Shop的提前 /拖期调度问题 ,并考虑了处理时间的不确定性 ,采用三角模糊数表示不确定性信息 ,提出了基于遗传算法的优化方法并以仿真实验验证了算法的有效性  相似文献   

8.
针对工件加工时间为非对称模糊数,极小化提前完工惩罚和拖期完工惩罚之和的均值的单机工期指派调度优化问题展开研究.证明了当模糊加工时间具有相同宽度比时,该问题是多项式可解的,并 给出了多项式求解算法.同时根据历史数据,构造了工期指派问题的调度模型,并利用所给出的算法求得最优解,从而 表明所提出的模型和算法的有效性.   相似文献   

9.
讨论带有退化效应的多个交货期窗口的单机排序问题。其目标函数有2种:第1种是带有提前、延误、交货期的开始位置、交货期的大小及最大完工时间的总费用;第2种是带有提前、延误、交货期的开始位置、交货期的大小和所有工件完工时间之和的总费用。目标是找到多个交货期窗口的最优位置、交货期的大小、属于每个交货期窗口的工件集合和工件的最优排序,使目标函数值最小。将该问题转化为指派问题,并证明其多项式时间可解。  相似文献   

10.
为降低柔性作业车间调度中的能耗,针对实际制造车间中工序加工时间和交货期的不确定性,将加工时间和交货期采用模糊数表示,建立以完工时间、平均满意度和最小满意度为柔性作业车间调度问题的多目标函数。同时设计了邻域遗传算法(GANS)求解该问题,算法采用机器选择的方法产生初始种群,并采用工序插入式方法对染色体进行解码;采用动态交叉概率及改进精英保留策略来保证种群的多样性和加快算法的收敛速度;并提出一种基于移动模糊关键工序的邻域结构来加强算法的局部搜索能力。最后通过数值实验验证了模型和算法的有效性和可行性,并对4个基准问题进行测试。结果表明:该算法在求解的精度、鲁棒性和解集的分布性方面与传统算法相比具有一定的优势,是一种有效的求解模糊柔性作业车间调度问题的新方法。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号