覆盖件产品CEG集成知识模型及表达

产品集成知识模型是对几何模型，特征模型及其相应建模技术进一步的综合和扩展，是实现产品生命周期内信息综合表达的关键，在分析覆盖件产品对象类层次的基础上，提出了几何特征，规则对象和约束方法的面向对象表达策略，建立了集成构形、工程和几何知识描述的覆盖件产品模型，利用基于STEP标准的EXPRESS语言和KBE开发语言，通过语言联编实现产品特征信息和工艺设计知识的高度集成来支持智能化工艺设计过程。     

基于知识重用的大型水轮机可拓方案设计

研究了知识表示与重用技术,提出一种基于可拓学原理和实例推理的知识重用方法.该方法用物元模型以定量与定性相结合的方式对实例推理中的实例和问题进行统一描述,采用基于距的检索算法获得符合设计制造要求的最佳匹配实例,应用可拓变换对检索实例进行适应性修改,以使新实例符合问题的需要.最后以大型水轮机选型方案设计为例进行了验证.     

Design and implementation of a case-based reasoning system for marketing plans

Unstructured intangible experiences and knowledge are usually difficult to represent and instantiate, which engenders the hardship of knowledge transfer and sharing. Past marketing plans are such valuable documents containing strategic planning knowledge and experiences.Case-Based Reasoning (CBR), which consists of retrieving, reusing, revising, and retaining cases, has been proved effective in retrieving information and knowledge from prior situations and being widely researched and applied in a great variety of problem territories.This paper targets at designing a CBR architecture and a method that facilitate the sharing and retrieving of cases of great concern to the marketing personnel. After an intensive survey of CBR methods and applications, a CBR system embedding multi-attribute decision making method, which provides both overall similarity level and similarity level of each selected attribute, is proposed to enhance the adaptation of a new marketing plan. In addition, a multi-attribute gap analysis diagram is developed to visualize the similarity along with the gap between candidate and target cases, so as to better support interaction and group decision making in the process of strategically formulating a new marketing plan. The CBR system was implemented and successfully demonstrated on case retrieval of a telecommunication company.     

一种新的智能设计知识建模方法

知识表示是人工智能研究的核心内容之一,设计知识的建模是一项重要而困难的任务。本文提出了一种用于表达设计过程知识的模型---基于设计模式的设计模型(DMOM),同时提出了用于表达设计对象知识的三种模型:功能模型、参数化模型、实例模型。DMOM把设计信息分为三类,分别描述产品的功能特征、技术性能、产品类型,通过把各类信息映射到相应的设计对象模型构造了三种设计模式,借助模式的转换来综合处理各类设计信息。     

A parameter-extended case-based reasoning method based on a functional basis for automated experiential reasoning in mechanical product designs

The mechanical product design process involves much experiential reasoning which relies extensively on accumulated experience knowledge and ambiguous synthetic decision of experts (ASDE). This makes it hard to achieve the automated, intelligent and rapid design of mechanical products. Furthermore, due to the lack of consideration of experts' cognition of product functions and structures in the application of the current case-based reasoning (CBR) method in the field of automated experiential reasoning (AER), the parameter solving process is separated from ASDE. Aiming at improving the accuracy and intelligence level of AER in mechanical product design, this paper proposed a parameter-extended CBR (PECBR) method based on a functional basis by integrating ASDE into AER. The PECBR method mainly contains two parts: firstly, in order to acquire and quantitatively describe expert experiential knowledge to provide an effective basis for AER, a knowledge representation method integrating a function-flow-parameter matrix set (FFP-MS) using functional bases and a parameter experiential correlation matrix (PEC-M) extracted from FFP-MS were presented for mechanical products, where the FFP-MS characterized the operation of function and energy flow during the working process of products. An acquisition rule for FFP-MS was designed to extract the degree of correlation between each two parameters, in which the implicit knowledge hiding among functions, flows and parameters was mined to form PEC-M; secondly, to cope with the difficulty in integrating ASDE into AER, a feature-weighted case adaptation (FCA) method was proposed by adopting a presented weighted kernel support vector machine (WK-SVM) and dynamic particle swarm optimization (DPSO). The FCA method can achieve the intelligent and automated solving of product parameters through identifying PEC-M during the case adaptation process. Two case studies on two-stage reducers and corn huskers were carried out to demonstrate the validity of the PECBR method. Compared with other conventional CBR methods, PECBR method can derive a more accurate value of parameters in mechanical product designs especially in the case of limited similar cases.     

范例推理中面向对象的范例表示研究

结合范例推理的具体特点,按照面向对象的形式定义,给出范例的面向对象表示方法.通过类的层次信息,方便地表示范例复杂的结构信息;它一方面克服了属性-值对表示法无法表示复杂结构范例的缺陷,另一方面将领域知识通过约束规则与范例的表示有机结合起来.在范例相似性计算上,区分类内相似性和类间相似性,使得相似性表示尽可能准确和科学,从而有效地拓展了范例推理系统中的知识表示能力.     

A generic, object-oriented case-knowledge representation scheme, and its integration into a wider information management scenario

Abstract: A knowledge base management system (KBMS) realises a combination of techniques found in database management systems and knowledge-based systems. At the data model and knowledge representation level, many systems of this kind constitute a marriage of the relational data model and the rule-based reasoning. Experience has shown that either approach is restricted in the way it can express the demanding information and knowledge structures required for applications like decision support systems. Two new technologies offer an exciting new integrated approach to knowledge management. Object-oriented database management systems (OODBMS) provide an object model that supports powerful abstraction mechanisms to facilitate the modelling of highly structured information. Whereas case-based reasoning (CBR) systems are knowledge bases which organise their capabilities around a memory of past cases and the notion of similarity. Both types of system are built upon two fundamental concepts: 1) the retrieval of entities with potentially complex structure, called objects in the former, and cases in the latter type of system; 2) the organisation of those entities in collections with common characteristics. In an OODBMS such collections are termed extents, and in CBR they are usually called categories. In either system, the conceptual meta notion to represent both, objects as well as extents, and cases as well as categories, is the class.
Revolving around a Conceptual Case Class and extending a standard object model, this paper proposes a novel and general approach to represent case-knowledge and to build KBMSs. The work presented here is a spin-off of the design of an object query language within the ESPRIT project Lynx.     

On technology for functional requirement-based reference design retrieval in engineering knowledge management

Engineering design is a knowledge-intensive process, and includes conceptual design, detailed design, engineering analysis, assembly design, process design, and performance evaluation. Each of these tasks involves various aspects of technical knowledge and experience. Whether this technical knowledge and experience can be effectively shared is key to increasing product development capability and quality, and also to reducing the duration and cost of the development cycle. Consequently, providing engineering designers various query methods for retrieving engineering knowledge is one of the most important tasks in engineering knowledge management.The study develops a technology for functional requirement-based reference design retrieval as a decision support mechanism, which can assist engineering designers to retrieve relevant design and associated knowledge for reference in conducting functional requirements of a product. This study involves the following tasks: (i) designing a functional requirement-based reference design retrieval process, (ii) developing techniques related to the technology for functional requirement-based reference design retrieval, and (iii) implementing a functional requirement-based reference design retrieval mechanism. The retrieval process includes the steps of functional requirement-based query, case searching and matching, and case ranking. The technology involves (i) a structured query model for functional requirements, (ii) an index structures for historical design cases, (iii) functional requirement-based case searching and matching mechanisms, (iv) a functional requirement-based case ranking mechanism, and (v) a case-based representation of designed entities. Finally, the experimental example with indexing and retrieving similar designed entities is conducted to demonstrate the proposed techniques worked efficiently.     

产品智能化设计中进行结构设计的方法

提出了联合采用聚类分析、模糊识别、基于实例的推理进行产品结构设计的方法,基本思想如下:①任一“产品超类”都可以按照“产品-部件-零件”的层次进行划分,由此建立一棵“树”。②一个“产品类”拥有许多以“参数”表达的技术属性。采用聚类的方法,可以把每个属性映射到“树”的某个结点,构成该结点的属性集,然后基于这个属性集、利用已有的产品实例建立一个对应于该结点的模糊模型。③采用模糊识别的方法,按照“树”的拓扑结构对当前待求的设计问题进行识别,实现产品在概念设计阶段的结构设计。④采用CBR方法,实现详细设计阶段的结构设计。本文方法适用于大多数机电产品的智能化设计。     

The documentation of product configuration systems: A framework and an IT solution

When designing and maintaining a product configuration system (PCS), complete and up-to-date documentation of the system is needed in the form of a product model that outlines the structures, attributes, and constraints of the PCS. Furthermore, up-to-date documentation for the PCS is crucial for maintenance, further development, system quality and communication with domain experts. Product models are the main communication and documentation tools used in PCS projects. Recent studies have shown that up-to-date documentation for the PCS is often lacking due to the significant amount of work required to maintain product models. To address these challenges, this paper proposes an approach for documenting the PCS that is based on the structure, attributes, and constraints modelled within the PCS, in which the product model is generated directly from the PCS. The suggested approach avoids knowledge duplication, as knowledge needs to be maintained within the PCS only. It involves two steps: the first is the building of the initial product model, which is used for the programming of the PCS. In the second step, the product model is generated directly from the PCS and is based on the structure, attributes, and constraints inside the PCS. The product model does not need to be maintained, therefore, outside the PCS. This approach meets the demand for agile documentation and efficient communication with domain experts, and uses the fewest resources possible. Furthermore, to support the framework, an IT documentation system is proposed that is capable of retrieving knowledge from the PCS and thus generating the product model. Our framework and IT documentation system were developed and tested at a case company on five different projects. The results confirm that benefits can be achieved by using the proposed IT documentation system, as time and resources are saved, while the quality of the PCS is improved.     

基于语义对象网络模型的产品知识表达方法

为表达产品知识及其语义内涵和约束关系,提出采用语义对象网络模型（Semantic Object Semantic Networks,SOSNs）表达产品知识。SOSNs是基于图并结合面向对象方法表达的知识模型,其中节点表示产品语义对象,有向边显性定义语义对象之间的语义关系,这种基于图的语义模型能够清晰的表示产品功能、行为、原理、结构、配置管理、约束等知识及其语义关系,将与产品开发相关的知识集成为一个逻辑整体,形成分层的结构化语义对象网络结构,便于组织和管理产品知识,易于实现知识的共享和重用。     

Logic-based query optimization for object databases

We present a technique for transferring query optimization techniques, developed for relational databases, into object databases. We demonstrate this technique for ODMG database schemas defined in ODL and object queries expressed in OQL. The object schema is represented using a logical representation (Datalog). Semantic knowledge about the object data model, e.g., class hierarchy information, relationship between objects, etc., as well as semantic knowledge about a particular schema and application domain are expressed as integrity constraints. An OQL object query is represented as a logic query and query optimization is performed in the Datalog representation. We obtain equivalent (optimized) logic queries, and subsequently obtain equivalent (optimized) OQL queries for each equivalent logic query. We present one optimization technique for semantic query optimization (SQO) based on the residue technique of U. Charavarthy et al. (1990; 1986; 1988). We show that our technique generalizes previous research on SQO for object databases. We handle a large class of OQL queries, including queries with constructors and methods. We demonstrate how SQO can be used to eliminate queries which contain contradictions and simplify queries, e.g., by eliminating joins, or by reducing the access scope for evaluating a query to some specific subclass(es). We also demonstrate how the definition of a method or integrity constraints describing the method, can be used in optimizing a query with a method     

Development of a product configuration system with an ontology-based approach

Product configuration is a crucial means to implement the mass customization paradigm by assembling a set of customizable components to satisfy both customers’ needs and technical constraints. With the aim of enabling efficient and effective development of product configuration systems by reusing configuration knowledge, an ontology-based approach to modeling product configuration knowledge is presented in this paper. The ontology-based product configuration models are hierarchically organized. At the lower level, a configuration meta-model is defined. Based on this meta-model, domain-specific configuration knowledge can be derived by reusing or inheriting the classes or relations in the meta-model. Configuration models are formalized using OWL (Ontology Web Language), an ontology representation language developed by W3C. As a result, configuration models have well-defined semantics due to the logic semantics of OWL, making it possible to automatically detect inconsistencies of configuration knowledge bases. Furthermore, configuration constraints are represented in SWRL, a rule language based on OWL. Finally, actual configuration processes are carried out using JESS, a rule engine for the Java platform, by mapping OWL-based configuration facts and SWRL-based configuration constraints into JESS facts and JESS rules, respectively. The proposed methodology is illustrated with an example for configuring the ranger drilling machine.     

Manufacturing cost modelling for concurrent product development

This research work aims to develop an intelligent knowledge-based system that accomplishes an environment to assist inexperienced users to estimate the manufacturing cost modelling of a product at the conceptual design stage of the product life cycle. Therefore, a quicker response to customers’ expectations is generated. This paper discusses the development process of the proposed system for cost modelling of machining processes. It embodies a CAD solid modelling system, user interface, material selection, process/machine selection, and cost estimation techniques. The main function of the system, besides estimating the product cost, is to generate initial process planning includes generation and selection of machining processes, their sequence and their machining parameters. Therefore, the developed system differs from conventional product cost estimating systems, in that it is structured to support concurrent engineering. Manufacturing knowledge is represented by hybrid knowledge representation techniques, such as production rules, frames and object oriented. To handle the uncertainty in cost estimation model that cannot be addressed by traditional analytical methods, a fuzzy logic-based knowledge representation is implemented in the developed system. Based on the analysis of product life cycle, the estimated cost included material, processing, machine set-up and non-productive costs. A case study is discussed and demonstrated to validate the proposed system.     

基于实例的变型业务流程设计的研究

重组企业业务流程可以提高企业对市场的竞争能力.把变型产品的业务流程看作是抽象的变型产品,提出了以实现业务流程重组为目标的变型业务流程设计框架.在该框架中,以场景和刻面概念分别作为描述实例的手段,消除需求和设计间的"语义断层";提出基于树匹配的实例检索算法,以提高实例检索的查准率和查全率.     

An investigation of the K-tree search algorithm for efficient case representation and retrieval

This paper presents a new method of retrieving cases from a case-base on the K-tree search algorithm. Building an automated CBR system relies on representing knowledge in an appropriate form and having efficient case retrieval methods. Using the Intelligent Business Process Reengineering System (IBPRS) architecture as a base, we discuss a model-based case representation approach to solve the knowledge elicitation bottleneck problems. In addition to presenting the model-based case representation method, we introduce a K-tree search method to transform the case base into a tree structure, and discuss how it can be applied to the case retrieval process in IBPRS. The basic idea of the algorithm is to use various attribute values defined in the case label as general information for the case matching and retrieval.     

Object Oriented Case Representation for CBR Application in Structural Analysis

Knowledge representation is an essential element of a problem-solving technique through computational work. This article describes the knowledge representation scheme formulated to represent a problem in the structural analysis domain for solution through case-based reasoning (CBR). The numerical knowledge is extracted from a real-life problem that can be used as an input in a case-based reasoner. The geometric topology, loading, and mesh distribution for structure from a solved problem is represented in the form of numerical values for easy adaptation by the new problem. The representation scheme is a step forward in development of a system to be utilized for the time-consuming structural analysis requiring heavy computational power, such as an aircraft wing and fuselage components. The success of the representation strategy is a proof that CBR can work as a powerful problem-solving tool in this domain.     

基于实例的产品设计知识获取方法及实现

现代产品设计是面向市场、功能驱动以及基于新知识的设计，而知识获取是关键步骤。采用设计实例的形式对已有设计进行封装和组织，通过产品设计实例面向对象表达模型，将设计需求（包括性能需求、环境约束和成本约束）、设计任务、设计过程和设计方案封装在一个设计实例中，体现了功能驱动、面向市场的现代设计特征。在此基础上，利用Sybase公司的PowerDesigner8.0建模工具，进一步提出产品设计实例的获取模型，并对实例获取的关键技术进行了讨论。以滑动轴承设计为工程应用背景，选择应用于涡轮机的四油叶径向滑动轴承为设计实例，详细描述了集成于SolidWorks2000的滑动轴承设计实例获取模块的应用过程，验证了上述模型的正确性和可行性。通过对设计实例进行表达、获取和存储，为后续的基于实例推理的产品设计方法打下基础，同时以对外提供功能的形式对并行设计环境下的功能检索提供支持，推动现代产品概念设计自动化进程。     

推理建模中基于KDD和粗糙集的案例修改

在应用基于案例推理技术进行智能建模时,案例修改后的案例质量好坏直接影响所建模型的精度,但是由于案例修改对领域知识的依赖性很强,采用一般手工案例修改方法尤法保证案例修改的质量,即无法保证智能推理模型的精度。基于以上原因,该文提出了一种新的案例修改方法,利用KDD技术,通过有效的多值关联规则挖掘算法从运行数据库中挖掘出案例各属性间的依赖关系,得到案例修改的基本关联规则集,在此基础上利用粗糙集理论对基本关联规则集进行简约,然后根据简约后的关联规则进行案例修改。在线对比实验证明,应用本文方法进行案例修改,提商了修改后的案例质量,从而提高了整体智能推理模型的精度。