产品族设计的多目标优化方法

为帮助产品开发团队在设计产品族的过程中,可以交互选择多种目标的优化方案,提出了产品族设计的多目标优化模型,并设计了多目标遗传算法对模型进行求解.建模过程中考虑了市场分割、产品效用、竞争产品、顾客购买行为、产品开发费用等因素.通过一个应用案例,验证了所提模型和方法的可行性.     

产品族架构设计与供应商选择的主从关联优化

针对产品族架构设计与供应商选择的关联优化问题，提出了基于主从对策的交互评价机制。根据主从决策机制建立主从关联双层规划优化模型，以产品族架构设计为主，供应商选择为从。模型上层以效用-成本比为目标，决策产品族架构设计方案。模型下层以成本为目标，决策供应商的选择。构建双层嵌套遗传算法求解模型，并添加具有产品族特色的编码处理策略。最后以客车底盘的案例对模型和遗传算法进行了验证。     

结合供应链设计的产品族模块配置的主从优化

针对考虑供应链设计的产品族配置优化问题,根据对产品族模块配置与供应链协同优化问题的属性分析,提出一种新的设计理念,即产品族的模块配置与供应链设计是主从关联的。基于主从对策的决策机制,建立了这种关联协同优化的混合0-1非线性双层规划模型,该模型上层是整个产品族的配置优化,以顾客效用与成本之比为优化目标,决策产品族的模块配置;下层是相应生产供应链的设计优化,选择不同的模块供应商与不同产品的制造商并以整个生产供应链过程的成本最低为优化目标。针对模型为0-1混合非线性的特点,上下层分别采用遗传算法设计求解,并以一个简化的发电机产品族的例子来加以说明,结果表明所提双层模型能够有效解决产品族模块配置与供应链协同优化问题,并能得到较优的产品族配置方案。     

产品族设计与供应商的订单分配关联优化研究

针对统一采购情形下产品族设计与供应商订单分配问题,提出了一个以产品族利润最大为目标,满足产品配置要求、供应商最小订单数量等约束的产品族设计与供应商订单分配关联优化模型,并开发了一种自适应遗传算法对模型进行求解。为了防止由于优化问题中存在的订单等式约束导致算法产生大量不可行的染色体,给出了一种按比例分配订单的染色体编码与解码方法。同时算法设计了自适应的交叉方式与变异方式尽可能避免陷入局部最优解。最后通过一个实例验证了所提优化方法和求解算法的有效性。     

供应商参与下的产品方案多目标优化与多属性决策规划方法

针对现有供应商参与下的产品方案规划方法在零部件优化和供应商评价等两方面所存在的局限性,提出零部件多目标优化和供应商模糊动态多属性决策评价相集成的二阶段规划方法。建立以产品零部件组合方案的质量、成本和交货期等为目标的数学优化模型,以Epsilon策略和主导性约束处理机制对强度Pareto多目标进化算法进行适应性改进后用于对该优化模型进行求解并获得有限数量的Pareto最优解。引入傅里叶级数对伯努利预测模型的误差进行修正来提高预测精度,将修正的伯努利预测模型和模糊动态多属性决策模型相结合用于对Pareto最优解中包含的各零部件供应商进行评价,进而确定出各零部件的最佳供应商和最终的产品规划方案。以供应商参与下的空分设备研发过程作为实例,进行数值仿真计算,结果表明所提出方法具有可行性与有效性。     

集成多准则供应商评价的产品配置方法研究

针对配置设计的产品在成本、质量、准时交货率等多方面受供应商影响的问题,提出一种集成多准则供应商评价的产品配置设计方法,包括配置模型的构建以及求解。首先采用TOPSIS方法对供应商进行多准则评价,将评价结果与模块实例相关联,构建集成化的配置模型。在配置模型的基础上,构建以供应商综合能力最优、成本最小为目标,客户的期望价格与配置规则为约束的集成供应商选择的产品多目标配置优化模型,并采用NSGA-Ⅱ算法求解。以高速列车转向架部分模块为例,证明了所提方法的可行性与有效性。     

考虑再制造的产品族配置主从关联优化

针对考虑再制造的产品族配置优化问题,建立了以产品族配置设计为主,再制造企业选择决策为从的混合整数非线性双层规划模型。该模型的上层以产品族的单位成本效用为优化目标,决策产品族的配置设计;下层以产品族的再制造成本为目标,优化再制造企业的选择。针对该双层规划模型,设计了一个双层嵌套遗传算法及相应的编码策略,并以一个简化的手机产品族为例验证模型的合理性和有效性,结果表明所提双层模型能够有效解决考虑再制造的产品族模块配置优化问题,并能得到较优的产品族配置方案。     

产品族配置与考虑升级的再制造设计主从关联优化

针对产品族配置与考虑升级的再制造设计协同问题,提出一种主从关联优化方法,建立了一个双层规划模型.该模型以产品族配置设计为主优化问题(主者),并以产品族的全生命周期利润最大化为目标建立上层模型;下层优化问题则是以再制造利润最大化为目标,决策如何选择产品的升级模块和再制造模块(从者).为了求解该模型,开发双层嵌套遗传算法及其相应的编码策略.最后,将该模型和求解算法应用于台式电脑产品族案例中,将所得的结果与两阶段方法进行比较,验证了其有效性及可行性,并说明了所提主从关联优化方法在解决产品族配置与考虑升级的再制造设计关联优化问题方面的优势性.     

基于供应链的供应商选择模型与算法

以石化企业为背景,研究了供应链中多供应商/多炼油厂的原油供应商选择问题,建立了以成本、质量、交货及供应链循环时间为目标的多目标采购优化数学模型,以实现供应商选择和最优采购计划的集成.然后,利用层次分析法(Analytic Hierarchy Process, AHP)与多目标规划相结合的方法求解模型得到供应商选择及优化采购方案.数值仿真结果表明所提出方法的有效性和实用性.     

基于SPEA2+的产品族模块单元多目标规划方法

在分析零件功能和物理特性的基础上,应用模糊数学理论给出产品族模块单元规划准则的量化计算方法,建立产品族模块单元多目标规划优化模型。针对传统的目标加权法在模型求解中的不足,采用改进的强度Pareto进化算法(SPEA2+)对模块单元多目标规划问题进行优化求解,从而得到一系列基于Pareto解集的产品模块规划方案,并利用模糊集合理论的Pareto综合选优方法得到了产品模块多目标规划的最优方案。结合项目实施以缝纫机为应用实例,验证提出方法的有效性和适应性。     

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...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

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...