基于AHP的看板系统绩效研究

为了使企业管理者得到满意的看板绩效,对看板系统进行了探讨。应用层次分析法的思想建立了看板绩效系统层次模型,并应用物流仿真软件Witness对实证中的看板系统进行仿真研究。结果表明,根据看板绩效系统的结果确定看板系统参数的选择方案,就可以使企业管理者得到满意的绩效指标。     

基于AHP的看板系统绩效研究

为了使企业管理者得到满意两看板绩效,对看板系统进行了探讨。应用层次分析法的思想建立了看板绩效系统层次模型,手应用物流仿真软件Witness对实证中的看板系统进行仿真研究。结果表明,根据看板绩效系统的结果确定看板系统参数的选择方案,就可以使企业管理者得到满意的绩效指标。     

制造过程精准作业控制仿真关键技术研究

通过看板管理,可消除生产过程的不合理库存,张紧生产中各环节,大幅度提高生产效率,实现制造过程精准作业控制.以生产看板为切入点,构造了制造过程的精准作业控制仿真体系;在该体系约束下,以Flexsim为仿真平台,生成了与真实车间布局和工艺流程相一致的制造系统仿真环境;以C++为开发语言,开发了看板生成关键程序,确保生产指令...     

JIT生产系统Petri Net建模与仿真研究

激烈的全球市场竞争要求企业对动态需求具有较强的反应能力，同时对自身生产系统的随机特性有较强的把握和控制。制造企业倾向于采用JIT看板生产理念来改善企业的QCD。这里首先建立JIT看板生产系统基本流程的Petri Net模型，然后运用WITNESS建立了一个单产品、多阶段、混联的JIT生产系统仿真模型，通过仿真实验，研究和分析了需求和生产两方面的随机变量在不同的组合下，其变异系数对系统绩效指标的影响。     

基于SimEvent的多产品多阶段看板生产系统设计与分析

为了确定多产品多阶段看板生产系统中的看板数量,提出一种事件驱动的建模仿真方法。根据看板生产系统看板、物料的流转特点,采用SimEvent工具的基本元素,建立了多产品多阶段看板生产系统的基本工序单元、原材料供应以及在制品与看板的流转模型;采用实体预载技术,在仿真初始为各工序配置指定数量的领用看板和生产看板;利用实体属性值实现了仿真过程不同类型实体的识别与流转调度。建立了一个多产品多阶段看板生产系统的SimEvent实例模型,仿真结果表明,该模型可以为两种类型的看板数设置提供决策支持。     

ADM看板生产管理系统在航天器研制领域的应用

针对车间生产制造信息化的需求,提出了一整套的软件系统建设理论,并结合实际案例,系统地阐述了看板系统(MES系统)在生产制造领域的应用效果和发展历程。看板系统以计算机技术为辅,通过信息传递对从物料齐套到产品完成的整个生产过程进行优化管理,当车间发生事件时,看板能及时做出反馈、报告,并用实时准确的数据对它们进行处理和指导。通过多角度的分析,论述了看板系统在生产制造业发展过程中的巨大作用和推动力。     

基于看板管理的中小型电子企业车间生产管理系统研究

针对中小型电子制造企业在车间生产管理信息化建设中存在着资金短缺、技术人员匮乏、信息化应用水平低等问题,结合制造执行系统等先进管理思想,构建了基于看板管理的中小型电子企业车间生产管理系统（SFCS,Shop Floor Control System）,该系统具有低成本、易实施的特点,建立了该系统的体系结构、功能结构、运行模式;并研究了基于JIT技术的生产作业信息看板管理和系统集成接口管理等关键技术。该系统已成功在某电子制造企业进行实施和应用,取得良好应用效果。     

基于RFID技术的无线制造车间智能看板管理系统研究

提出和研究了用“RFID（Radio Frequency Identification，射频识别）”技术建立生产车间看板管理系统的体系结构和实现框架，通过对生产车间的人员、容器、设备和仓库配备读写器和智能卡的方案并设计相应的协同工作流程和应用系统，展示了RFID技术在看板管理中的应用价值并有效地解决传统看板管理中存在随着需求变化看板数量变更不及时、看板易丢失、不易重用等问题。最后，以开发的原型系统验证本方案的可行性。     

数控加工车间的集成生产计划与控制模式研究

针对传统的数控加工车间的生产计划与控制模式的弊端,构建了一种基于TOC的MRPⅡ生产计划系统和JIT生产控制系统相结合,同时考虑资源约束和订单插入的集成生产计划和控制模式.该模式能以生产需求、JIT拉动与APS模拟排产相结合的方式进行生产计划排产,同时利用车间能力需求计划、看板系统和PDM技术对生产过程实施实时跟踪控制.此模式对数控加工车间的生产效率提高具有重要意义.     

面向拉式生产系统的蚁群劳动分工建模及仿真

分析了拉式生产系统中的看板控制策略所存在的局限性,论述了看板控制策略与群集智能中的固定阈值蚁群劳动分工模型之间的相似性,提出将后者引人看板控制策略,以弥补看板控制策略缺乏全局优化能力的不足,实现平衡生产.据此对基本的同定阈值蚁群劳动分工模型进行了改进,建立了多状态蚁群劳动分工模型.通过一个多状态蚁群劳动分工模型执行过程的示例,绐出了其算法实现步骤,进而选取一个典型的生产加工实例,采用该模型进行了计算仿真实验,结果表明了该模型的可行性和有效性.     

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.     

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.     

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.