含提前期的混合回收闭环供应链牛鞭效应抑制

为了抑制混合回收渠道下闭环供应链中提前期导致的牛鞭效应,研究了一种鲁棒控制方法。构建了混合回收闭环供应链基本模型,基于离散Takagi-Sugeno模糊控制系统,并考虑提前期对牛鞭效应的影响,建立了一类含提前期的混合回收闭环供应链模糊模型。根据不同周期下的库存状态,分别设计了制造商和零售商的生产和订购策略。进一步提出一种新的模糊鲁棒H∞控制方法,该方法不仅可以有效抑制牛鞭效应,还可以实现闭环供应链系统的鲁棒稳定。通过仿真实验验证了所提方法的可行性和有效性。     

不确定供应链非线性系统的模糊鲁棒H_∞控制

为解决系统不确定参数和外部不确定需求引起的供应链非线性系统运作波动较大的问题,研究了一种鲁棒控制方法。基于离散Takagi-Sugeno模糊系统,建立了一类不确定供应链非线性系统的模糊模型。通过在每个最大交叠规则组中构建一种离散型分段Lyapunov函数,并应用并行分布补偿原理,提出一种新的模糊鲁棒H∞控制方法,该控制方法可在减少求解线性矩阵不等式个数的同时,保证不确定供应链非线性系统的鲁棒稳定。结合某二级不确定供应链非线性系统的实例进行仿真实验,实验结果验证了所提方法的有效性。     

随机供应中断下含提前期的供应链应急策略

为使发生随机供应中断的供应链仍能满足顾客需求,研究了一种供应链应急鲁棒策略。基于TakagiSugeno模糊控制系统,在随机供应中断下构建了一种含提前期的供应链应急模糊模型。根据不同周期下供应链各成员的库存状态,为制造商和分销商设计了生产策略和应急订购策略。提出一种模糊鲁棒控制策略来抑制提前期和不确定需求对供应链应急系统的影响。由应急订购策略和模糊鲁棒控制策略组成的应急鲁棒策略可以实现供应链应急系统的低成本鲁棒稳定运作。通过仿真实例验证了供应链应急鲁棒策略的可行性和有效性。     

一类参数和时滞不确定的闭环供应链动态模型与鲁棒H∞控制

建立了一类参数与时滞不确定的闭环供应链动态系统模型,包括具有参数不确定的产品回收模型、具有时滞不确定的再制造模型、具有参数和时滞不确定的第三方逆向物流模型三种典型的闭环供应链模型。分析了闭环供应链动态系统的鲁棒运作问题。针对闭环供应链动态系统运作过程中参数与时滞不确定干扰的问题,给出了解决供应链动态模型的鲁棒H∞控制策略及其线性矩阵不等式算法。通过库存状态的静态反馈控制,抑制了供应链动态系统中的不确定性干扰,使供应链运作达到理想状态。最后,以结合国内钢铁行业废钢回收运作状况为背景,进行了仿真计算,并验证了鲁棒H∞控制结果。     

不确定环境下的鲁棒多产品、多周期供应链网络设计模型

在成本和客户需求不确定的条件下,研究了由供应商、工厂、分销中心和最终客户构成的多产品、多周期供应链网络设计问题。针对成本和需求不确定性,采用情景树方法进行建模。在同时考虑解鲁棒和模型鲁棒基础上,建立了以供应链运作绩效最大化为目标,网络结构设计、物流运作等为约束条件,节点选择、连接路径等网络要素和生产、运输、库存等物流量为决策变量的鲁棒供应链网络设计模型。针对由不确定情景数众多导致的模型规模过大的问题,通过情景缩减技术进行了筛选,降低了求解难度。最后,通过数值算例验证了文中所建鲁棒供应链网络设计模型的稳定性和有效性。结果表明,所提出的供应链网络设计模型在确保总体绩效的同时,能够有效应对成本和需求的不确定性扰动,并为具有不同风险偏好的决策者提供了更多可供选择的方案。     

考虑提前期压缩的动态供应链鲁棒控制

为实现考虑提前期压缩的动态供应链系统的低成本鲁棒运作,研究了一种成本优化策略和鲁棒控制方法。建立了一种提前期压缩成本与压缩量间的量化关系模型,通过对不同库存水平下的压缩成本与缺货成本进行比较,提出一种成本优化策略。根据供应链节点企业的不同库存状态,建立了一种考虑提前期压缩的动态供应链模型,并应用模糊鲁棒控制方法实现了各模型间的柔性切换。通过仿真实例验证了成本优化策略和鲁棒控制方法在降低系统总成本的同时,可以保证系统的鲁棒稳定。     

考虑异质需求的再制造系统动态模型与鲁棒H_∞控制

针对消费市场对新产品和再制造产品存在的异质需求,建立了一组考虑产品需求可替代、时滞不确定性和需求不确定性的再制造系统动态模型,包括制造商自行回收模型、第三方回收模型以及再制造参数不确定的闭环供应链模型。分析了再制造系统的鲁棒运作,给出了这一组再制造系统动态模型的鲁棒控制策略和线性矩阵不等式算法。仿真计算表明,所提出的鲁棒控制策略能够有效抑制再制造系统运作过程中的不确定影响,使再制造系统达到稳定状态。     

随机提前期下非线性供应链库存优化策略选择

在供应链运作实践中,提前期不确定是一个常见的管理难题。为明晰随机提前期对供应链系统的影响机理,并提出抑制随机提前期对供应链系统性能负面影响的策略,建立了一个复杂非线性供应链系统动力学模型,该模型考虑订单交叉、不允许退货等前提条件,并引入随机需求和随机提前期。这些前提条件使模型更符合实际,同时也大大增加了模型的复杂度。将订货量波动、服务水平和库存成本作为评价供应链性能的指标,通过仿真实验,研究不同库存策略下,随机提前期对这些性能的影响。研究发现,存在比传统策略更优的库存策略,这些策略能在一定程度上抑制随机提前期的负面影响;随机提前期波动只对各项指标的大小变化有影响,并不改变各项性能指标在整个库存控制策略域内的变化趋势。     

异质队列的分布式鲁棒解耦控制

基于分布式控制结构和基于图论的通信拓扑描述方法,针对车辆节点动力学的不确定性设计了一种异质队列的鲁棒解耦控制策略。采用乘性不确定模型覆盖由下位控制器和车辆动态特性构成的队列节点的动态特性,在此基础上通过通信拓扑的特征值分解和线性变换将异质队列控制系统分解成H∞范数有界的不确定部分和一个对角系统,从而实现队列系统的解耦。进一步对该控制系统的鲁棒稳定性、跟踪性能和队列稳定性进行理论分析。通过与非鲁棒控制器,以及不同通信拓扑下的系统性能进行台架实验对比分析,对所提方法的鲁棒稳定性、跟踪性能和队列稳定性进行了验证。     

基于神经网络的机器人鲁棒跟踪控制

针对具有参数不确定以及外部扰动的机器人系统,提出了一种基于神经网络的鲁棒跟踪控制策略。鲁棒补偿控制器用于消除系统参数以及外部干扰引起的不确定性的影响,再利用神经网络学习系统不确定性未知上界。仿真结果表明,方法能有效克服机器人系统模型的不确定性和外部干扰,具有良好的鲁棒性和控制性能。     

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.     

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。     

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....     

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.