协同设计环境下基于语义的本体建立方法

分析了获取概念及其关系是本体建立的瓶颈的原因,提出一种在协同设计环境下基于语义的本体建立方法。各Agent抽取的术语集合经过预处理,以WordNet提供的术语语义为基础,经过基于语义的聚类,生成概念集;再根据术语语义关系与概念关系之间的映射规则建立概念的关联,从而构造概念树并建立本体。这种半自动的本体建立方法避免了因对概念理解不统一而产生的不一致性,得到的本体易于扩展。     

Manufacturing challenges in obtaining tailor-made closed-cell structures in metallic foams

Life cycle engineering design (LCED) is the key and comprehensive technology to realize manufacturing industries’ sustainable development. Its main objective is to support design teams to create products considering the entire product life-cycle from conception through manufacturing and assembly to disassembly, recycling, disposal, and lifecycle assessment. So LCED should be collaboratively implemented among the different departments. This paper puts forward knowledge management architecture of LCED based ontologies and multi-agent system. The definition of the domain-specific ontology, the multi-agent architecture are described. Based on the two concepts, this paper discusses the detailed construction of CAD agents, LCED evaluation agents and knowledge maintenance agents and the system implementation. It can fulfill the concurrent collaborative developing of a product under distributed environments and also meet the requirement of knowledge sharing, interoperability, reusing among the whole lifecycle of product.     

Agent与对象

要在工程领域中应用多Ａｇｅｎｔ 系统作为新的分布式智能手段,实现机械产品的协同设计与开发,首先必须把握好Ａｇｅｎｔ 的概念和原理,为建立产品设计与开发的计算机辅助分布式智能协同环境打下坚实的理论基础。本文阐述了Ａｇｅｎｔ 的引入和概念,并基于面向对象方法这一软件系统分析、设计和实现的基础框架结构,提出了面向Ａｇｅｎｔ 方法是面向对象方法的智能外延,使Ａｇｅｎｔ在软件实施和工程应用中成为可行     

Research on ontology-based integration of product knowledge for collaborative manufacturing

One of the most important research subjects germane to knowledge management in collaborative manufacturing is the integration of heterogeneous product knowledge distributed among different collaborative enterprises. To deal with the problem of optimization of knowledge integration in collaborative manufacturing, an ontology-based framework of knowledge integration is presented to transform the problem of knowledge integration into a problem of ontology integration. First of all, a collaborative business process for collaborative enterprises is described, and then an ontology-based framework of knowledge integration is established. Under the condition of analyzing the structure of knowledge ontology, an ontology schema of knowledge concept is discussed. Aiming at the ontology schema, a method of ontology integration based on ontology similarity is improved. The method is composed of ontology mapping and ontology merging, which is based on calculated result of ontology similarity between local ontology and global ontology. Finally, the implementation of the framework of knowledge integration is described, and the application results meet the requirement of the knowledge integration to ensure that validity of the ontology integration method was proved.     

产品概念设计自动综合求解与系统实现

运用键合图方法定义了基本元件，并提取其输入输出特征与能量传递和转换函数。研究了单输入单输出机械产品的概念设计自动求解。提出了目标驱动的逐段综合求解策略和基于模糊距离的方案评价方法，开发了相应的概念设计原型系统。结合面向对象和规则方法来表达设计知识，其中面向对象方法用来封装元件，形成元件类，规则则用来指导搜索过程。通过自动门驱动装置的设计实例，说明该方法适用于定常和非定常的设计要求。     

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。     

核级部件智能CAD系统的工程规范标准知识库研究

核级部件的设计必须满足相关工程规范标准的要求和规定,规范标准具有复杂的知识体系,使得如何表示工程规范标准的知识成为实现核级部件智能CAD系统的关键.根据工程规范标准的知识特点及设计过程的要求,结合框架、产生式规则和着色网等知识表示方法,提出了面向对象的混合知识表示方法.基于此表示方法给出的知识表示实例表明,该方法能够准确、完整地表示工程规范标准的复杂知识体系,并具有良好的知识重用性.     

面向流程的企业知识地图及其本体实现

为解决当前知识管理系统普遍存在的知识管理与组织业务流程缺乏有效结合的问题,实现企业范围内知识资源的集成与协同利用,通过分析知识地图技术及其在企业知识管理中的应用模式,构造了面向流程企业知识地图分层管理模型,提出了基于本体技术及Web本体描述语言的一种模型实现方法,并通过应用实例验证了模型的有效性。该模型在实现企业范围内知识集成和协同的同时,也为协同商务环境下组织间知识的协同管理创造了条件。     

基于本体的装配公差类型的自动生成

为进一步减少产品设计的不确定性,解决公差信息在异构系统之间难以有效共享和顺畅传递的问题,将本体技术引入到装配公差类型的自动生成方法中。首先,构建了基于空间关系的装配公差表示模型,并采用OWL断言表示了模型各层中的约束关系。其次,通过提取表示模型中的相关概念和关系,构建并实现了装配公差表示的本体。基于构建的本体及空间关系与装配公差类型之间的映射关系,采用SWRL定义了装配公差类型的生成规则。再次,基于实现的本体及定义的规则构建了可选装配公差类型生成知识库系统,在此基础上设计了装配公差类型的自动生成算法。最后,通过工程实例分析验证了生成算法的有效性。     

A Prototype Knowledge-Based System for Conceptual Synthesis of the Design Process

This paper presents a knowledge-based system "KBCS", the "Knowledge-based conceptual synthesiser" that supports the synthetic phase of conceptual design. It was developed using an expert system shell called CLIPS. By using this knowledge, physical behaviour can be derived from a desired function or desired behaviour, and a functional model which represents causal relationships among the functions and behaviours can be created. In addition, complicated desired functions which cannot be matched with the functional output of any behaviour after searching the object-oriented behaviour base, will be automatically decomposed into subfunctions by means of relevant function decomposition rules. A case study for the conceptual synthesis of an automatic assembly system provides an application of this intelligent design environment, and a demonstration of its methodology. In this paper we also describe how two popular AI representation techniques, object-oriented representation and production rule representation, can be usefully integrated to solve the problem.     

Exploring Semantic Web technologies for ontology-based modeling in collaborative engineering design

This paper describes a preliminary attempt at using the Semantic Web paradigm, particularly the Web Ontology Language (OWL), for domain-specific engineering design knowledge representation in a multi-agent distributed design environment. Ontology-based modeling to the engineering design knowledge on the Semantic Web is proposed as a prelude to the meaningful agent communication and knowledge reuse for collaborative work among multidisciplinary organizations. Formal knowledge representation in OWL format extends traditional product modeling with capabilities of knowledge sharing and distributed problem solving, and is used as a content language within the FIPA-ACL (Agent Communication Language) messages in the proposed multi-agent system architecture. As an illustration, engineering design knowledge of automatic assembly systems for manufacturing electronic connectors, which contain a group of electro-mechanical components, is represented in OWL format, with its inherent structure-function-process relationships defined explicitly and formally, to facilitate semantic access and retrieval of electro-mechanical component information across different disciplines. The proposed approach is viewed as a promising knowledge-management method that facilitates the implementation of computer supported cooperative work (CSCW) in design of Semantic Web applications.     

An effective integration approach toward assembly sequence planning and evaluation

An integration strategy for assembly sequence planning and sequence scheme evaluation is proposed. This strategy can be used to plan a reasonable assembly sequence, to optimize a sequence scheme, and to predict whether a collision will occur between the assembly tool and assembled components by considering factors like target components and assembly resources. A hybrid method is presented for assembly sequence modeling that combines human-computer interactive operations to manually build a hierarchical assembly sequence main model and a hybrid graph method to automatically generate sub-assembly sequence schemes of the main model. An optimization algorithm based on time-cost is introduced to handle a best candidate components selection. This relieves the problem of limited capability found when handling large size assembly models with traditional methods. The essential issues involved in system implementation are discussed as well; these include a representation method for the assembly consequence model, an optimization model of assembly sequence planning, and an object-oriented system architecture model employed with multi-agent technology for visually evaluating the assembling process. This system, KM computer-aided assembly process planning, KMCAAPP, has been developed on the basis of our previous work, KMCAD3; KMCAAPP uses the presented approach. KMCAAPP can be integrated with CAD model from KMCAD3D. A case study shows that the presented approach can use large CAD assembly models and delivers a feasible and effective way to integrate the assembly sequence planning process with scheme evaluation by visually evaluating the assembling process. This allows the identification of design errors in a timely manner and mitigates economic loss.     

协同设计中基于约束的冲突检测

如何实时检测设计冲突从而维护设计一致性是协同设计的关键问题。提出了基于约束的自动冲突检测方法；介绍了设计约束在产品信息模型中面向对象的表征；讨论了工程设计中的约束满足问题及其区间求解算法，并在此基础上发展了一个基于网络的冲突检测器。冲突检测器能够在协同设计过程中实时检测设计冲突，避免不必要的设计反馈和重复磋商，从而提高了设计效率。并以减速器协同设计的冲突检测实例显示了冲突检测器的有效性。     

产品创新设计中基于本体理论的客户知识集成技术研究

为了支持产品创新设计过程的深入研究,针对客户知识在产品创新实践中的集成问题进行了研究.首先,根据产品创新活动的特点,建立了一种产品创新设计中的客户知识集成模型;其次,提出了基于"问题域-功能域"的客户知识转换方法,同时使用本体理论对客户知识进行建模,构建了包括客户创意、感性知识、客户需求、基本知识在内的客户知识概念本体树模型,实现了对客户知识的本体描述;随后,提出了用客户知识服务引擎来实现客户知识请求匹配的方法;最后,结合产品创新中客户知识集成系统的开发,对上述模型及方法进行了验让.     

A design representation scheme for collaborative product development

Design is an integral component of product development, which includes manufacturing. In order to avoid costly reworks and delays, and to reduce the lead-time in product development, effective communication of design concepts among the various stakeholders such as customers, designers and engineers is of utmost importance. In this respect, functional representations provide a methodology, which can be used to describe a design or product effectively. However, function is not the only type of information that needs to be communicated among the various stakeholders during a design process. Other types of information such as design specifications and constraints, which are non-functional, also need to be taken into account. This non-functional information cannot be adequately expressed using existing functional representations. Accordingly, in this work, a novel purpose-behaviour-structure (PBS) representation scheme to capture vital design knowledge for collaborative product development is proposed. The proposed PBS representation scheme can be used by designers working in a collaborative environment for product development. A case study on the design of a vacuum cleaner is used to illustrate the functionality of the PBS representation scheme. The details of the representation scheme are presented in this paper.     

知识表示中多色图的应用

为了让知识本体表示方法能同时描述概念和概念间关系的多种特性,在图论的基础上,借鉴已有研究成果,采用多色图理论实现了本体的形式化描述,通过图的多色性质反映概念、关系的多种特性;将属性与概念和关系分离,便于多色图知识表示方法描述能力的扩展,提高了方法的柔性;实现了基于多色图的本体并、交、差的基本运算。最后应用基于多色图的本体表示方法建立了钣金工艺本体片断的形式化描述模型,验证了方法的有效性。     

知识集成的本体理论和框架研究

对制造企业知识进行本体的分类和描述，体现了分类、描述的思想和方法；对知识共享和集成的关键技术——本体映射和本体语义提升进行框架、理论和算法的研究；在此基础上，给出了知识集成的结构模型。基于本体的知识集成方法，改变原有数据库集成中使用中间代理、软件接口等技术所造成的语义信息不清、信息丢失等缺陷，为企业实现知识语义级的共享和集成提供了解决方法和理论依据。     

基于面向对象和数据库技术的机床选择专家系统

机床选择是机械加工工艺设计中的一个重要环节。专家系统是人工智能的一个主要研究方向,非常适合处理需要大量经验知识的设计问题。提出将面向对象方法和数据库技术相结合,进行了机床选择专家系统总体结构设计,并介绍了各模块对应的功能,研究了基于产生式规则的知识表示方法、基于关系型数据库的知识库的管理和基于正向推理方式的推理机的设计和推理过程等关键技术,以Visual C++和Access为开发工具,实现了机床选择专家系统。     

网络化协同设计工具

针对网络化设计多主体、多模式、异地分布等特点，建立了一个支持多模式设计方法的通用型网络化协同设计支持系统，介绍了集成在该系统中的面向产品设计需求的协同工具，给出了典型协同工具的设计和实现方法，并开发了相应的软件系统。协同工具具有良好的可集成性，可根据需求增减，亦可独立使用，从多角度满足异地协同设计的需求。     

基于ART-2神经网络的设计知识需求研究

通过分析产品设计知识获取和知识共享研究中存在的问题,结合本体理论的运用,构建了产品设计中的概念语义,并利用OWL+RDF+XML形式化语言给出了案例知识的表达,在研究ART-2神经网络竞争学习和自稳机制的基础上,设计了案例的多级组织,实现了基于案例推理(CBR)的检索机制,提升了案例分类和检索的效率。同时,利用案例的聚类和学习机制,研究特征权值的自动获取和优化,并通过应用实验验证了该研究成果的实用性和有效性,从而较好地解决了产品设计中的知识需求。