基于BASS扩散需求的按订单组装模式生产库存模型

为了得到单周期按订单组装模式的生产库存模型,在考虑单周期生产过程动态特征的基础上,提出了基于BASS产品扩散需求的组装商利润连续时间模型。通过模型分析,以最大利润为目标,得到了两种产能条件下的组装商生产库存模型。通过数值仿真,得到了最优数值解。结果表明,该模型能够有效反映单周期按订单组装模式下组装商的生产过程以及生产库存和需求的关系。     

重复购买下的产品扩散最优动态定价

产品价格作为市场营销的关键因素,直接影响产品扩散,为了明确产品价格和产品扩散之间的内在机理,在Bass模型的基础上,考虑重复购买和价格因素,构建产品市场扩散非线性微分动力学模型。对模型进行微分方程求解,获取产品累积扩散量和产品市场稳定累积扩散量的解析式;考虑成本学习效应,以最大收益为目标,求解模型对应的HJB方程,得到重复购买下产品扩散最优定价的解析式。通过仿真分析模型主要变量和最优定价的演进过程产品表明:最优定价随时间推移不断降低,在产品生命周期末期趋于平稳,最优定价应采取撇脂策略;灵敏度分析进一步揭示了各主要参数与最优定价的内在联系,为企业制定新产品开发和营销战略提供了理论指导。     

产出率具有学习效应和需求依赖库存的EPQ模型

为研究生产过程中产出率具有动态学习效应、需求依赖于库存水平的生产库存优化模型,建立了允许缺货和不允许缺货两种情形下的总平均成本最小化成本函数。针对两类情形下成本函数的高度非线性,采用牛顿迭代法得到最优生产量和最优生产时间。数值与敏感性分析表明,在早期生产阶段学习效应对最优生产量与最优生产时间有显著影响,在后期产出率将达到一个稳定的状态,学习效应发挥作用有限。在不允许缺货情形下,学习效应条件下的最优生产量和最优生产时间均小于无学习效应条件下的最优生产量和最优生产时间;在允许缺货情形下,学习效应条件下生产库存模型的缺货时间更长、生产时间更短、最优生产量更大。随着学习系数的增大,最优生产量快速增加、最优生产时间减少。     

基于柔性优化的轧制批量生产计划模型

为了满足市场对钢材品种多样化的需求,在提高客户满意度的同时兼顾生产经济性,有必要制定灵活的生产计划,以保证轧制生产资源在最优配置下的充分利用。针对钢铁企业多样的产品需求和不断变化的生产条件,建立了钢铁轧制生产计划柔性优化混合整数非线性规划模型,深入考虑各周期产能平衡的耦合性、钢材品种的可替代性、坯料匹配的多样性和拖期生产等柔性条件,并综合库存、生产准备、产能等其他约束,提出钢铁轧制批量生产计划柔性优化策略。采用优化建模工具Lingo建模求解,并通过实例对不同规模下柔性优化模型的有效性和可行性进行了验证,为实际钢铁轧制生产计划的制定提供了指导。     

面向产品生命周期的库存分析与订货策略优化研究

产品的积压库存增加了企业的经营成本,严重影响了企业的经济效益和竞争力。针对B公司主要产品C产品的库存现状及问题原因,提出面向产品生命周期的订货策略优化。基于三阶多项式曲线模型对C产品的实际销售数据进行模型拟合,确认该产品正处于生命周期阶段中的成长期;结合成长期的库存特点,通过对常见的订货策略对比分析,选择(t,s,S)和(Q,R)订货策略进行仿真优化研究。Arena仿真结果表明：两种面向成长期产品的订货策略均使得C产品的库存水平明显降低;依据实际销售数据分析证明,(Q,R)订货策略的月平均库存降低了31.2%,总成本减少了25.1%,且缺货风险较小,更加稳定,为适用于成长期C产品的最优订货策略。基于产品实际销售和库存数据的订货策略的定量分析与仿真研究,并为积压库存的问题研究提供了新思路。     

面向产品全生命周期的需求信息管理模型研究

为了在产品全生命周期管理系统内有效实现以客户需求为中心的信息管理,提出了面向产品全生命周期管理的需求信息管理模型.集成客户需求信息,采用结构图法建立需求信息流程图.概念化描述需求信息的三个维度,应用矩阵方法分析产品全生命周期管理部门级、协同级和系统级三种不同层次的模型结构,并采用语义方法描述模型的特征.在视图结构关系研究中,应用函数形式化方法,以数据流视图为中心,研究模型视图结构关系的映射机制,并对其模型的存储结构进行表达.最后,以汽轮机产品为例,进行应用研究.结果表明,研究需求信息管理模型,为产品全生命周期管理系统设计、制造、销售等阶段提供了实施策略,最大限度地满足了客户需求.     

零售商从事产品翻新的闭环供应链差异定价策略

针对市场上可能存在的新产品、再制造产品以及翻新产品的异质需求环境,分析了不同市场情形的形成条件及产品的需求函数。针对一个由原始设备制造商、零售商和第三方回收商组成的闭环供应链系统,建立了四种生产模式下考虑零售商从事产品翻新的差异定价模型,得到了相应的最优定价策略,并进行了对比分析;在三种产品需求同时存在的市场情形下,比较了零售商和制造商分别从事产品翻新时的最优策略,并分析了制造商选择零售商从事产品翻新的条件。研究表明,在零售商从事产品翻新时,再制造产品和翻新产品会对新产品产生市场"挤兑效应",同时伴随有"利润侵占"现象;零售商利润与闭环供应链系统总利润在同时生产三种产品时达到最高。与制造商从事产品翻新相比,零售商从事产品翻新有利于零售商而不利于制造商,但闭环供应链系统总利润相对较高;在一定条件下,制造商会考虑选择零售商从事产品翻新,以求得系统利润最大化。     

不同制定者以旧换新策略下的产品绿色度与定价

为提高产品绿色度水平,促进废旧产品循环再造,考虑企业自主推行以旧换新策略,基于制造商实施产品绿色化设计战略,构建了无以旧换新、制造商自主以旧换新、零售商自主以旧换新3种二级供应链决策模型,分析了3种模型下制造商产品绿色度水平、产品市场零售价格、旧产品返利价格的最优决策。通过数值仿真,对3种模型下产品价格、产品需求和企业利润进行了比较分析,并讨论了老顾客市场占比率、旧产品折旧度对企业最优利润的影响。研究表明,产品价格在零售商以旧换新策略下最高,产品需求在制造商以旧换新策略下最高;制造商利润在制造商以旧换新策略下最大;零售商最大利润依赖于产品绿色度水平、老顾客市场占比率和旧产品折旧度,当它们分别低于某阈值时,零售商利润在制造商以旧换新策略下最大,当它们分别高于该阈值时,零售商利润在零售商以旧换新策略下最大。     

基于额外费用的交货期相关定价模型研究

从定义供应链企业和客户对交货期要求的估计概率入手,在时间敏感需求条件下,以单位时间预期收益最大化为目标,构建了供应链企业基于额外费用的交货期相关定价模型;然后,分析了模型的最优性,并给出了相应的最优决策策略;最后,通过数值算例,分析了模型参数对最优策略的影响,指出供应链企业在竞争中如何采用额外费用相关定价策略.     

分散决策下考虑异质需求的闭环供应链差异定价

针对消费者市场除了新产品需求外,还可能存在再制造产品和翻新产品需求的异质需求环境,分析了不同市场情形的形成条件和需求函数。针对一个由第三方回收商、制造商和分销商组成的三级闭环供应链系统,建立了不同生产模式下的闭环供应链差异定价模型,得到了相应的最优定价策略,并从不同角度进行了对比分析。研究表明,制造商生产再制造产品或翻新产品,会产生市场的挤兑效应,但不存在利润侵占现象;整个供应链系统及其各个成员,在制造商选择同时生产三种产品时可以获得最高的利润,而选择生产新产品和再制造产品时的单位平均利润则较高。     

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.