双抽样均值—标准差联合控制图的构建及参数设计

在参考双抽样均值控制图及双抽样标准差控制图的基础上,构建了双抽样均值一标准差联合控制图.建立了控制图参数设计的优化模型,用以监控生产过程质量,并通过遗传算法完成了模型求解.采用马尔科夫链方法,完成了联合控制图平均运行长度性能指标的计算.基于该指标,通过两阶段抽样和可变抽样样本及抽样区间均值-标准差联合控制图的性能对比,分析验证了该控制图的性能优势.     

过程均值偏移随机的EWMA控制图优化设计

针对过程均值偏移随机的情况,提出一种统计经济最优的指数加权移动平均控制图优化设计方法。该方法将过程受控、失控未检出、失控被检出并进行恢复这三个阶段定义为一个周期,分析了三个阶段的平均时长及质量成本构成,通过计算产品质量特性超出规格界限的概率量化缺陷产品所造成的质量损失,以单位时间内期望成本最小为目标建立指数加权移动平均控制图优化模型并设计了遗传算法,优化了样本容量、采样间隔、平滑界限和控制界限等参数。通过与休哈特均值控制图、传统指数加权移动平均控制图等进行对比验证了该模型的优越性。     

VSSI EWMA均值控制图和预防维修联合经济设计模型

针对设备异常导致过程质量均值发生漂移的可修系统,提出一种考虑最小维修的样本容量和抽样区间均可变(VSSI)的指数加权移动平均(EWMA)均值控制图和预防维修集成决策方法。在假设控制图误报警实施最小维修、正确报警和预防维修实施完美维修的前提下,分析确定了系统存在的3种更新策略情景;在此基础上,以单位时间期望成本最小化为目标构建了VSSI EWMA均值控制图和预防维修联合经济设计模型,并给出了基于帝国竞争算法的模型求解过程。算例分析结果表明,该模型由于考虑了最小维修以及控制图与预防维修的耦合关系,能够通过对决策参数的进一步优化降低系统综合成本。最后,利用正交试验设计和回归分析方法,对模型参数的灵敏度进行了分析。     

VSS EWMA均值控制图和预防维修联合经济设计模型

针对生产过程质量特性均值漂移由设备异常导致的可修系统,提出一种可变样本容量指数加权移动平均均值控制图和预防维修联合经济设计模型。在该模型中,系统被界定存在控制图误报警、正确报警、预防维修点到达3种更新情景;针对样本可变情况,分析得到了控制图两类错误期望概率;为避免平均失控运行长度带来的计算复杂等问题,以抽样间隔为基本分析单元代替传统方法的失、受控两阶段分析模式,建立了各更新事件期望周期成本和时长的函数表达式,进而构建了单位时间期望成本最小化决策模型,并与蒙特卡罗仿真方法进行了对比分析。应用实例分析结果表明,该模型能够较真实地反映生产系统实际运行状况,并可为系统优化分析提供支持。最后,对模型参数进行了灵敏度分析。     

带有辅助样本的X控制图经济设计

针对异常因素产生时间服从指数分布的过程,采用带有辅助样本的X(SSX)控制图监控过程质量特性的均值和方差,研究了SSX控制图的经济性能。构建了SSX控制图监控生产过程的费用函数模型;采用模式搜索算法对费用函数模型进行寻优,得到SSX控制图的最优决策变量、平均调整时间及费用,并比较了SSX、均值极差和变采样间隔均值极差控制图的经济性能。仿真结果表明,SSX控制图比均值极差控制图能够明显缩短平均调整时间和减小控制图的监控费用,且在大部分的偏移大小下,SSX控制图的经济性能都要优于变采样间隔均值极差控制图;对参数的灵敏度进行分析,结果表明模型中参数变化对采样间隔、控制图的控制限系数都有一定影响。     

多变异源过程控制与指数加权移动平均控制图的应用研究

改进休哈特控制图能够解决多变异源过程控制虚发警报错误过高的问题,但是对均值偏移的检出力过低。本文研究的目的是将指数加权移动平均(EWMA)控制图用于多变异源过程控制,提高控制图对均值偏移的检出力。通过对多个变异源的方差分析,基于对部分方差估计,给出指数加权移动平均控制图在多变异源过程控制的应用方法。通过计算指数加权移动平均控制图的平均运行长度,并与改进的休哈特控制图作比较,证明指数加权移动平均控制图在检测多变异源过程均值偏移时检出力有较大提高,应用实例的结果表明当偏移量小于1σ时,检出力能提高10倍以上。     

双抽样控制图的效率评价与优化设计

研究了双抽样均值控制图的效率评价与优化设计问题。分析了双抽样均值控制图的平均运行长度的计算方法,在此基础上建立了控制图参数设计的优化模型,并通过与原有的双抽样均值控制图的性能对比,验证了该优化设计模型的有效性。     

基于高质量过程的指数分布中位数控制图的统计设计

针对事件间隔时间服从指数分布的高质量过程的监控问题,给出参数已知和未知情况下的中位数控制图设计方法;应用条件错误警报概率、受控时控制图的平均运行链长均值AARL及其标准差SDARL分析了参数估计对所设计控制图性能的影响;在小样本情况下,采用Bootstrap方法对所设计控制图的控制限进行调整,结果表明调整后的控制限能够有效减少参数估计对控制图性能的影响。最后用实例说明了所设计控制图应用的有效性。     

基于鲁棒参数控制方法的可变控制线控制图

针对在制造过程中应用鲁棒参数控制时,其过程均值和方差都会经常改变,且无法直接使用现有的控制图技术进行统计过程控制,提出了基于应用鲁棒参数控制的可变控制线控制图的设计方法.它不同于传统的适应性控制图设计方法,是该研究通过对过程均值和方差变化的有效估计,给出了可变控制线的调节律算法,为控制图自动跟踪过程变化提供了一种可行的方法.通过实例分析,验证了上述方法的有效性和实用性.     

VSSCL均值控制图和预防维修策略联合经济设计

针对输出质量特性服从正态分布的随机偏移单部件可修系统,研究了可变样本容量和控制线(Variable Sampling Size and Control Limits,VSSCL)均值控制图和预防维修策略联合经济设计问题。首先,构建了VSSCL均值控制图和预防维修策略联合经济设计的集成框架,揭示控制图和预防维修策略运行的耦合机制;然后,基于VSSCL均值控制图和系统状态特征参数,针对给出的集成框架确定了可能形成系统更新的四个维修事件的发生概率,并进一步利用更新过程理论和全概率公式,建立了VSSCL均值控制图和预防维修策略联合经济设计的平均单位时间成本最小决策模型;同时,针对具体实例,将构建的联合设计决策模型和独立设计决策模型进行比较分析,结果表明联合设计决策模型具有明显的经济优势;最后,利用回归正交试验设计方法对模型参数的灵敏度进行了分析。     

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.