基于本体映射的设计知识库搜索方法

针对智能设计方法中的知识库搜索问题,提出了一种基于本体映射的设计知识库搜索方法。为描述复杂的产品设计知识,使用本体知识表示方法建立了产品设计知识库。将产品设计方案的搜索问题转换为本体映射问题,使用本体映射算法搜索本体知识库中符合设计需求的产品设计方案。设计并实现了一种结合了元素级映射技术和结构级映射技术的本体映射算法,并应用于基于本体映射的设计知识库搜索。最后,通过飞控作动器设计实例,验证了基于本体映射的设计知识库搜索方法的正确性和有效性。     

基于本体的CAPP知识库管理系统研究

为了合理有效地利用工艺知识,本文研究了工艺知识的获取和分类,提出了一个基于本体的工艺知识表示模型,将本体作为具体知识表示的元知识,与此同时,给出了一个基于本体的知识库框架结构,讨论了基于本体的知识检索和工艺知识库的维护,最后给出实例进行了验证。     

面向产品创新设计的广义专家群体知识获取

为更好地从互联网获取适用的知识,以激发创新灵感,提出了一种面向产品创新设计的广义专家群体知识获取的思路及方法。首先对普通专家提供的知识样本进行分析,并提取样本特征。然后,针对产品创新设计知识的特点,构建了融入感性语义词汇的领域本体。基于领域本体,对专家知识样本特征词汇进行了扩展。在此基础上,通过搜索和过滤,获得了来自互联网的特殊专家的知识文本。进而运用知识元抽取技术,构建了广义专家群体知识库。最后,通过实例说明了特殊专家知识获取及过滤的效果,以及广义专家群体知识库的构建形式及结果。     

基于本体的产品服务知识表示方法研究

为解决产品服务活动中知识难以被发现和重用的问题,对产品服务过程所涉及的知识进行了分析,提出了基于本体的知识表示方法, 该方法可实现本体的定义与建模,以及本体内各概念相似度的评定。通过对领域本体的构建, 实现了服务过程所涉及知识的逻辑结构与具体内容的全面语义描述和后台并联。构建了基于本体的产品服务知识管理系统,该系统能实现产品服务活动案例所涉及知识的获取和重用,满足知识源于服务 活动,又重用于服务活动的循环。最后以某航空发动机非计划维修服务为例,验证了该知识表示方法的有效性。     

基于逆向工程和粗糙集的协同设计领域本体构建方法

针对协同设计领域本体构建难的问题,建立了基于逆向工程和粗糙集的协同设计领域本体学习模型.通过对产品数据管理数据库进行数据库逆向工程,获取产品数据管理数据库的物理数据模型和概念数据模型,从中提取与产品信息和开发过程有关的实体信息.建立了关系数据库模式到本体的映射规则,并从中学习本体概念和概念之间的关系.同时,根据获得的实体信息从产品数据管理数据库中采集数据构建面向特定主题的知识库,并利用粗糙集理论从知识库所存储的数据中发掘更多的概念和隐含的语义信息.该协同设计领域本体构建方法可以继承企业已有的知识和经验,减少领域专家的依赖,提高本体构建效率,降低本体构建成本.     

基于本体的液压元件知识建模研究

为了解决液压元件信息的形式化规范表示问题,以支持液压系统设计过程中知识的重用和共享,该文在系统描述了液压元件的分类和模型信息的基础上,提出了基于本体的液压元件知识建模方法,包括基于OWL的本体构建过程和基于MYSQL的知识库表示过程;并面向液压集成块设计,讨论了液压元件的本体建模过程,实现了液压元件知识的规范化描述和重用。     

基于OWL的工艺BOM本体构建方法研究

针对工艺物料清单在异构系统上传递和共享困难的问题,引入网络本体语言的形式化表示技术,研究工艺物料清单本体的构建方法。首先在零件加工面与工艺关系的基础上,设计了基于特征表面的工艺物料知识表示模型,通过产品零件加工表面与加工工艺的对应关系,工艺步骤到生产资料的映射关系,将工艺知识与工艺物料信息相结合;其次借助模型构建基于网络本体语言(Web Ontology Language,OWL)的工艺物料知识元本体模型,实现工艺物料清单(Bill of material,BOM)的本体构建;最后以联轴器为例,在protégé软件上对联轴器的工艺BOM进行本体构建,为后续的工艺BOM自动生成、知识推理及知识库构建奠定基础。     

基于PDM的工艺知识库管理方法研究

为了完成基于产品数据管理的计算机辅助工艺设计系统中工艺知识库管理系统的开发,提出了一种基于产品数据管理的工艺知识库管理方法。工艺知识包括工艺资源信息、工艺实例和工艺决策知识三类,据此构建了基于产品数据管理的工艺知识库管理系统的体系结构,提出了基于物料清单的工艺实例表示方法和检索方法、基于数据库中view技术的工艺资源信息的检索方法和基于工艺决策知识三视图模型的工艺决策知识库的维护策略。最后,介绍了样机系统的应用。     

数控机床故障诊断本体建模研究

??针对数控机床故障诊断领域知识复杂、异构、表示不完备和共享困难等问题,采用了一种基于本体的知识表示方法,结合故障诊断需求,提出了一种适用于数控机床故障诊断领域的本体构建方法及知识表示模型,构建了包含故障现象、故障原因、故障部位和解决方法等的数控机床故障诊断知识本体。使用本体开发工具Protégé4.3构建了某型号数控机床故障诊断本体并做了相关的一致性检验,为数控机床智能故障诊断的本体推理提供了研究基础。     

基于本体的车身设计知识库的构建方法研究

在研究本体、知识库相关理论,分析车身设计领域知识形态结构的基础上,建立了车身设计知识本体,并将本体论引入到车身设计知识的管理系统中,提出了构建基于本体的可重构的车身设计知识库,并在理论上提出了该系统的框架结构。     

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.