改进遗传算法求解面向订单多目标排产问题

针对面向订单的多目标排产优化问题,综合考虑订单的延期成本、库存成本和生产单元的负载均衡,构建了面向订单的多目标排产优化的数学模型;针对上述模型设计了一种基于矩阵编码的改进遗传算法,并详细介绍了算法初始种群产生策略、行交叉算子、列交叉算子、行变异算子、列变异算子、适应度函数和选择算子的设计。通过实验对比,验证了提出的算法可以有效地解决面向订单生产的多目标排产优化问题,降低企业生产成本,充分利用生产资源。     

自动化制造单元最小完工时间调度问题的混合启发式算法

自动化制造单元最小完工时间调度问题属于NP-hard难题,目前尚缺乏有效的调度方法。为此,提出基于遗传和禁忌搜索的混合启发式算法,用以搜索一组最满意的机器人搬运作业排序。以遗传算法为基本结构,在初始种群产生和交叉、变异操作中引入禁忌搜索技术,以提高优化质量。基于搬运作业规则的初始种群构造算法和两阶段交叉、变异算子克服了传统算子对可行搬运作业排序的破坏,而邻域移动算子则保证了禁忌搜索的多样性和集中性。最后,随机实验结果验证了算法的有效性。     

基于改进粒子群优化算法的多目标铜卷加工生产调度研究

针对多目标铜卷加工生产调度问题,提出一种自适应的改进粒子群优化算法。该算法采用基于个体拥挤距离排序的外部种群保留策略以避免陷入局部极值,基于个体拥挤距离概率更新全局极值以及基于支配关系更新个体极值,同时采用基于非支配解和单点交叉的内部种群规模自适应调整策略以及自适应动态惯性权重来保持种群的多样性。通过应用实例验证了该方法求解多目标铜卷加工生产调度问题的有效性。     

基于可行域遗传算法的装配作业调度

为了对装配环境下的车间作业进行调度,提出了一种基于可行域搜索的遗传算法。为保证算法在进化过程中染色体始终保持合法性和可行性,在种群的初始化、交叉和变异等阶段,分别设计实现了首代修复算子、可行域交叉算子和可行域变异算子。可行域交叉算子和可行域变异算子的设计组合实现了算法的可行域搜索,减小了搜索空间,省去了复杂的解码修复操作,提高了求解效率,为解决复杂的装配车间调度问题提供了有价值的参考。通过与简单规则、禁忌搜索、普通遗传算法实验结果的比较,验证了所提算法的合理性和优越性。     

双阈值控制的遗传算法求解作业车间调度问题

针对作业车间调度问题自身的求解难点和遗传算法的特点,分析了目前遗传调度算子存在的问题,提出了一种双阈值控制的多父辈POX交叉算子,即用父辈相似度阈值调整变异的时间,收敛度阈值调整变异概率,在变异的同时提高交叉性能.利用这种方法求解作业车间调度问题,能防止父个体相似时交叉不能产生新个体,防止交叉产生的优秀个体再变异,并防止早熟现象.仿真实验表明,该算法可以显著提高解的质量和收敛速度.     

基于时窗的双资源约束车间调度研究

针对复杂制造环境下双资源约束作业车间调度问题,提出基于时窗调度策略的继承式遗传算法。该算法基于时窗交集充分利用数控设备加工时工人的时窗空隙;以信息素为载体传承父辈染色体种群的进化经验,并采用基于流量的改进伪随机比例转移规则和自适应云调整参数,生成分支种群;仿照动物的种群组织模式提出多种群King交叉进化模式,并针对双资源约束特点引入资源进化算子;基于被支配域的概念提出扇形分割的轮盘赌选择算子,以较小的计算复杂度选择非劣解集和较优个体。在采用马尔科夫链知识对整个算法的全局收敛性进行理论分析后,通过对随机算例仿真运算结果的统计分析,表明该算法虽然解分布均匀程度不甚理想,但算法搜索性能和收敛性较优。     

多阶段可替换分组并行机调度的串行遗传算法

针对一类多阶段可替换分组并行机混流生产调度问题,以最小化生产线工人总数和最小化订单提前期为目标建立了问题的数学模型,提出一种串行遗传算法;串行算法分步逐步确定最小的工人总数及其最优的工人配置,编码与生产线工人配置方案一一对应,采用包含多种规则的混合调度规则解码获得每阶段的调度方案,解码结果自动满足模型约束;算法采用改进的单点交叉算子和自适应种群规模,计算量小、求解速度快。针对不同规模的算例,仿真验证了算法的有效性。     

变邻域改进遗传算法求解混合流水车间调度问题

针对混合流水车间调度问题的NP难特性,提出一种改进的混合变邻域搜索的遗传算法。建立了数学模型,提出了算法的总体流程,设计了基于操作的编码和解码方法,并采用NEH启发式算法产生初始种群。随机采用基于位置的交叉和线性次序交叉,选用反转逆序的变异算子,交叉变异后合并子代与父代,保留较优个体,对当前最优个体执行变邻域搜索,以增强遗传算法的局部搜索能力。通过初始对比实验,证明了NEH启发式算法能够产生质量更好的初始解,随机采取两种交叉算子能够提高算法的搜索效率,标准算例实验结果表明所提算法能够有效求解混合流水车间调度问题。     

可调加工时间炼钢-连铸的灰狼优化调度算法

炼钢-连铸(SCC)是钢铁生产中的瓶颈,SCC生产过程中最后一个阶段的加工时间可调。可调加工时间SCC调度问题是NP难组合优化问题,高质量的SCC调度算法可以较大地提高生产效率。基于问题特征,研制了求解该问题的高效灰狼优化(GWO)算法。首先设计了新的解码方法对解进行解码。同时提出了种群初始化方法,以得到具有一定质量和多样性的初始种群。其次,研制了一种基于多操作的搜索算子,该算子包含3种不同操作,在一定程度上实现了GWO算法的集中性和多样性的平衡。此外,设计了重启操作,以提高GWO算法的多样性。对比实验说明了基于多操作的搜索算子的有效性。此外,与4种有效调度方法的对比说明了GWO算法的高性能和优越性。     

准时制生产模式下预制构件订单间调度与订单内调度的联合优化

在预制构件实际生产过程中，通常一个订单中包含多个工件。为满足客户交货期和方便管理，来自同一订单的工件需要连续生产，就需要解决订单间调度与订单内调度的联合优化问题(JOP＿IOSIOS)。该问题是比传统流水线调度问题更为复杂的问题，是典型的NP-hard问题。为解决该问题，通过对工序约束、订单间、订单内约束等的深入分析，基于准时制生产模式，以最小化总提前和拖期惩罚费用为目标建立了混合整数规划模型。鉴于问题的复杂性，基于分解与协同进化框架，提出一种有效的协同进化混合遗传—离散差分进化算法(CoHGA-DDE)。其主要思想是首先构造订单间调度种群和订单内调度种群，然后对两个种群分别采用离散差分进化策略和遗传进化策略，并通过两个种群之间的交互作用来提高各自性能。为验证协同进化框架和CoHGA-DDE的有效性，设计了协同进化遗传算法(CoGA)、协同进化离散差分进化算法(CoDDE)、遗传算法(GA)、离散差分进化算法(DDE)、和迭代贪婪(IG)算法。对不同规模订单进行测试，计算结果显示，与GA,DDE和IG相比，协同进化方法具有更好的求解质量和鲁棒性，而在协同进化方法中，CoHGA-DDE具...     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.