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Knowledge integration and sharing for complexproduct developmentZ.Y. Wua, X.G. Minga, L.N. Hea, M. Lia & X.Z. Liaa Shanghai Key Lab of Advanced Manufacturing Environment, School of MechanicalEngineering, Shanghai Research Center for Industrial Informatics, Institute of ComputerIntegrated Manufacturing, Shanghai Jiao Tong University, Shanghai, P.R. ChinaPublished online: 04 Jun 2014.

To cite this article: Z.Y. Wu, X.G. Ming, L.N. He, M. Li & X.Z. Li (2014) Knowledge integration and sharing for complexproduct development, International Journal of Production Research, 52:21, 6296-6313, DOI: 10.1080/00207543.2014.923121

To link to this article: http://dx.doi.org/10.1080/00207543.2014.923121

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Knowledge integration and sharing for complex product development

Z.Y. Wu*, X.G. Ming, L.N. He, M. Li and X.Z. Li

Shanghai Key Lab of Advanced Manufacturing Environment, School of Mechanical Engineering, Shanghai Research Center forIndustrial Informatics, Institute of Computer Integrated Manufacturing, Shanghai Jiao Tong University, Shanghai, P.R. China

(Received 12 May 2013; accepted 30 April 2014)

Product development is a highly creative and knowledge-intensive process that involves extensive information andknowledge exchange and sharing among geographically distributed teams and developers. How to best integrate suchheterogeneous product knowledge has become an extremely important knowledge management (KM) subject associatedwith product development. Product development knowledge integration and sharing is becoming a key issue in the enter-prise KM. This paper addresses the challenges of product development knowledge integration and sharing during productdevelopment. The aim of this research work effort is to develop a method to enhance the integration and sharing ofproduct knowledge during the development phase. This study presents a systematic approach to developing knowledgeintegration and sharing for product development. The proposed approach includes the steps for designing a frameworkof product development knowledge sharing, developing representation model for product development knowledge,designing product development knowledge sharing process, designing product development knowledge integration ontol-ogy, developing knowledge integration and sharing method for product development based on ontology, and implementa-tion of product development knowledge integration and sharing method. The proposed method could bring out anefficient and proactive way for knowledge integration and sharing among product developers in the product developmentprocess.

Keywords: knowledge management; knowledge representation; knowledge integration; knowledge sharing; productdevelopment

1. Introduction

Information technology has promoted our society gradually into knowledge economy from product economy. Organisa-tion for Economic Co-operation and Development (OECD) defines that knowledge economy is the economy which isbuilt on knowledge and information production, distribution and application. In knowledge economy era, value creationrequires more and more knowledge and information to support enterprise activities. Knowledge management (KM) asan activity has already existed, however the conceptual use of KM to describe the activities of enterprise knowledgeprocess began in Drucker. KM will make the organisation and individual have stronger competition strength, and makebetter decisions.

Product development knowledge in the manufacturing industry is a very special type of knowledge that supportshow products can be best produced. These development knowledge and other intangible properties have become themost important and valuable assets for product development. Product development knowledge, including standards,development data, development tools, product development documentation and case as well as many trivial aspects, stillrests in the information system or in the minds of experienced designers (Denkena et al. 2007). They need to work inthis job or field for several years before becoming experts of product development. And without these experts, tacitknowledge is not available to be shared or be transferred as needed (Liao 2005). For most manufacturing companies inChina, the shortage of knowledge workers or experts is one of the biggest gaps standing in the path of their growth.This situation has become a difficulty for most China manufacturing companies. New methods need to be developedand proposed to tackle such a problem. With the development of product knowledge modelling and information soft-ware technologies, classification and representation are now possible. The classification and representation of knowledgeis still difficult but serves as the foundation in managing knowledge.

The motivation of this study mainly lies in: the knowledge recommendation based on the personal profile that couldact as a supplement to the traditional knowledge query. In the product development process, it spends a lot of time forengineers to search knowledge from a repository with large amounts of data and information. Product development is

*Corresponding author. Email: wuzhenyong@sjtu.edu.cn

© 2014 Taylor & Francis

International Journal of Production Research, 2014Vol. 52, No. 21, 6296–6313, http://dx.doi.org/10.1080/00207543.2014.923121

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becoming increasingly knowledge intensive in manufacturing enterprises. Product development engineers sometimes arenot sure on what knowledge they really need and sometimes do not clearly describe which keywords should be used tosearch knowledge form the knowledge repository. Due to the above disadvantages in the traditional knowledge querymode, the knowledge recommendation based on the personal profile could recommend some potentially useful knowl-edge to those product development engineers who may really need them.

To overcome these challenges, this paper proposes a framework for product development, knowledge representationand sharing. Key techniques for knowledge representation model and knowledge sharing are elaborated. A case study isalso illustrated to show the implementation and potentials of the framework.

The remainder of this paper is structured as follows. Some state-of-art reviews are briefly introduced in Section 2. Aframework for product development knowledge sharing is depicted in Section 3. For the key techniques and solutions, i.e.knowledge representation model and sharing method, a detail of the construction is given in Section 4. A case study is pro-vided to demonstrate the implementation and potentials of the framework in Section 5. In Section 6, an experiment is per-formed for the method proposed in this paper. And finally, conclusions and future research directions are made in Section 7.

2. Current research status

In recent years, there have been significant and considerable developments in product KM, especially in product devel-opment. Therefore the relationship between KM and product development is becoming an important issue in academicand industry areas (Liao and Wu 2010). Bernard and Xu analyse the knowledge evolution process in product develop-ment activities and propose an integrated knowledge reference system (Bernard and Xu 2009). Kim and Kim proposecausal knowledge, present a mathematical comparison of procedural knowledge and causal knowledge, and discuss thepotential roles and feasibility of causal knowledge across product development KM (Kim and Kim 2011). To speed upthe product design efficiency, product designers would like to utilise the past experience and know-how in assisting thedesign of new products or in the enhancement of existing ones. Design structure matrix is considered to be a suitablemeans to capture and manage the system-level design knowledge (Tang et al. 2010). Bradfield and Gao investigatedKM problems in the new product development process of a multi-national manufacturing company, and proposed anontology-based methodology to disseminate knowledge to users (Bradfield and Gao 2007). Zhang et al. develop an inte-grated KM and reuse framework for Product-Service Systems business in construction machinery industry (Zhang et al.2012). Dekkers, Chang and Kreutzfeldt present a systematic review of the literature focused on the interface betweenthese two areas and identify six core themes based on 49 retrieved papers (Dekkers, Chang, and Kreutzfeldt 2013).Chen presents a systematic approach to developing a knowledge integration and sharing mechanism for collaborativemoulding product design and process development in his study (Chen 2010).

Mountney, Gao, and Wiseall consider the use of manufacturing knowledge in the earlier, preliminary stage of designwhere the geometry is not so developed and where development of manufacturing technology may be required, and a pro-totype KM tool was developed by them to meet those requirements (Mountney, Gao, and Wiseall 2007). Cai et al. attemptto shed some light on the mechanisms underpinning knowledge sharing in supply chains in their paper. In particular, theyfocus on knowledge sharing in a dyadic buyer–supplier relationship (Cai et al. 2012). Zhen and Jiang design a knowledgegrid-based knowledge query platform to support innovative product design activities (Zhen and Jiang 2008). Martín et al.propose a new paradigm where intelligent KM is integrated into the conceptual repository of management information,they present a technique for the design and implementation of a distributed intelligent system that is designed through thenormalisation of KM (Martín et al. 2012). Dantas and Farias present conceptual navigation and NavCon, made use ofontology as metadata to contextualise user search for knowledge (Villela Dantas and Muniz Farias 2010). Huang, Lin andChan develop a system that comprises a semantic tagging mechanism and triple-pattern and visual searching mechanismsby taking advantage of Semantic Web technology and the topological characteristics of knowledge maps (Huang, Lin, andChan 2012). Jayaram and Pathak propose a finer grained view of knowledge integration mechanisms in collaborative sup-ply chains. Specifically, they propose two different types of mechanisms that are in play within a collaborative supplychain; short-term knowledge sharing and iterative knowledge enrichment (Jayaram and Pathak 2012). Hou and Pai developa knowledge visualisation methodology that computer systems can automatically convert the textual knowledge into visual-ised display (Hou and Pai 2009). Zhen, Song and He make an explorative study on the personal KM, and analyse variousforms of personal knowledge resources in the product development process and propose a model of recommender systemsfor personal KM for knowledge sharing among members in the collaborative environment (Zhen, Song, and He 2012). Linand Hsueh propose a knowledge map management system to facilitate KM in virtual communities of practice and developknowledge map creation and maintenance functions by utilising information retrieval and data mining techniques (Lin andHsueh 2006). Chen, Chen and Wu present a systematic approach to develop a framework for managing empiricalknowledge to support a professional virtual community in knowledge-intensive service industries (Chen, Chen, and Wu

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2012). Chau, Moghimi and Popovic propose a knowledge ecosystem to frame the rehabilitation engineering KT processfrom need to product (Chau, Moghimi, and Popovic 2013).

Besides the above KM or knowledge sharing techniques, Wang and his team propose an agent-based KM systemwhich builds on organisational knowledge resources and works with the advanced product quality planning concept aswell as KM agents, the proposed framework reflects how the tool with KM agents seeks significant inroads into processknowledge repository to recommend a solution for decision-making in semiconductor manufacturing enterprises (Wanget al. 2010). Zhen, Huang and Jiang propose a workflow-based recommender system model on supplying proper knowl-edge to proper members in collaborative team contexts rather than daily life scenarios (Zhen, Huang, and Jiang 2009).Young et al. presents a view of the current status of manufacturing information sharing and discuss the potential forheavy weight ontological engineering approaches so as to facilitate sharing knowledge in cross-disciplinary productdevelopment teams (Young et al. 2007). Shaw and Edwards study key components of a knowledge sharing strategy, andthe relationships between it and manufacturing strategy. They also make comments on the development of action plansfor better KM (Shaw and Edwards 2006). In recent years, knowledge recommendation is becoming a new hotspot inboth academics and industries, and shown its efficiency in many areas. Li et al. propose a social recommender systemwhich generates discussion thread and expert recommendations based on semantic similarity, profession and reliability,social intimacy and popularity, and social network-based Markov Chain models for knowledge sharing in online forumcommunities (Li, Liao, and Lai 2012). Zhen et al. propose a model of distributed knowledge recommender system tofacilitate knowledge sharing among collaborative team members. Their study also provides a new framework for simu-lating and studying individual or organisational behaviours of knowledge sharing in a collaborative team (Zhen, Jiang,and Song 2010). Urwin and Young focus upon a rapid development and deployment method in their work that enablesthe capture and representation of machining knowledge so that it may be shared and reused by design engineers toaccelerate the design-make process (Urwin and Young 2013).

From the above literature review, we can see that they are mainly based on a centralised knowledge repository. Bythese KM methods, product development engineers usually need input keywords to query their knowledge from knowl-edge repository. It is cumbersome for engineers to get the knowledge they may need after browsing all the query result.Product development is an intensive knowledge involved, often complex, fuzzy and iterative process, and the needs andspecifications of the knowledge is more refined as product development process develop towards its goal. Product devel-opment engineers sometimes may not clearly describe what kind of knowledge keywords should be keyed in to queryknowledge from the knowledge repository. To make up for the gap, this study proposes a framework that containsknowledge representation model and active knowledge sharing mode, which can efficiently supply useful knowledge forengineers to support their development tasks in the process of product development.

3. A framework of product development knowledge sharing

The framework proposed in this paper has two key techniques: knowledge representation model and knowledge sharingmode. In product development process, there are various types of knowledge resources that are stored in the form ofdocument, software or tacit knowledge from knowledge experts. A proper knowledge representation model can supporteffectively to knowledge sharing in product development. The framework of product development knowledge sharing isillustrated in Figure 1.

It mainly has three parts: knowledge ontology, product development knowledge sharing process and product devel-opment process. Firstly, knowledge ontology is divided into four types: know-what, know-how, know-why and know-who. The details are elaborated in Section 4.1. The second part in this framework is the knowledge process that containsknowledge demands, problem description, knowledge query, knowledge matching, knowledge recommendation andknowledge application. The details are elaborated in Section 4.2. The development process is the third part in thisframework that composes of idea generation, concept design, preliminary design, detail design, technical implementationet al. Each stage of product development knowledge characteristic can map to a knowledge process. And engineers mayinvolve in various kinds of products.

4. Technology solutions for product development knowledge sharing

4.1 Product development knowledge representation model

In order to propose an appropriate model, the product development knowledge is divided into four categories defined byOECD in product development stage (Foray and Lundvall 1997): know-what knowledge, know-why knowledge, know-how knowledge and know-who knowledge.

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� Know-what: the definitions and contents from activities of product development process.� Know-why: the executive motivation or intention from developmental activities in each phase of product devel-

opment process, such as product functional requirements, customer requirements, design specification, experi-ence knowledge, and mouldability assessment data.

� Know-how: the executive steps for activity from the process of product development as well as the requiredproduct operation knowledge such as CAD model views, FMEA diagram, virtual prototypes, computer algo-rithms and design procedures.

� Know-who: the domain expert and resource application in executing every activity from the process of productdevelopment such as product design engineer, expert, CAD\CAE and material database.

The proposed model for knowledge representation in product development is shown in Figure 2. There are three lay-ers in this representation model, namely resource layer, XML topic map (XTM) layer and ontology layer. The resourcelayer provides information and knowledge resource contain various types of information and knowledge source to meta-data. The XTM layer establishes links between the knowledge resource and the knowledge application. The ontologylayer provides a knowledge ontology which consists of know-what ontology, know-why ontology, know-how ontologyand know-who ontology.

The resource layer provides product development data, information, tangible and intangible knowledge. There arevarious types of information and knowledge through product development process, and they need to be classified andorganised. These information or knowledge contain customer requirements, decision tables, product development cases,design rules, detailed drawings, CAD model views, FMEA diagram, computer algorithms multimedia, flow charts andphotographs. And these information and knowledge resource is the foundation of knowledge representation.

The XTM layer provides a mechanism for representing information about the structure of information and organisingit into topics. The topic has associations and occurrences that it can represent and define relationships between thesetopics. Information and knowledge about the topics can be connected by traversing the associations and occurrenceslinked to the topic. The hyper-graph method ensures the knowledge representation model is unified in the same

Know-what ontology Know-how ontology Know-who ontologyKnow-why ontology

knowledgeresources

knowledgeontology

Knowledgedemands

Problemdescription

Knowledge queryKnowledgematching

Knowledgerecommendation

Knowledgeapplication

ServiceProcess

Development Process

Ideageneration

Concept design Preliminarydesign

Detaildesign

TechnicalImplementation

Product 1 Product 2 Product 3 Product n···Productcategory

Engineer 1 Engineer 2 Engineer 3 Engineer n

Users

Figure 1. The framework of product development knowledge sharing.

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resolution of knowledge representation, which guarantees the model is reusable and robust. It is important to facilitateapplications to check effectively and consistency of this model. The XTM layer establishes links between the informa-tion/knowledge and knowledge ontology.

The ontology layer provides definitions for product development knowledge, attributes and relationships betweeneach other to achieve knowledge sharing. The ontology is defined to four types: know-what ontology, know-why ontol-ogy, know-how ontology and know-who ontology. This ontology can help to associate design processes, design objectsand knowledge objects together, realise the representation of four kinds of knowledge and lay the foundation for the fol-lowing knowledge sharing and reuse.

4.2 Product development knowledge sharing

In this section, the process of knowledge development knowledge for knowledge integration and sharing is first devel-oped. Based on this sharing process, the ontology-based framework for product knowledge integration and sharing arethen designed. The integration and sharing process for product development knowledge is designed based on the ontol-ogy-based framework for product development knowledge integration.

4.2.1 Product development knowledge sharing process design

Based on the knowledge integration (Chen, Chen, and Chu 2009; Chen 2010) and knowledge sharing (Wang and Noe2010; Zhen, Jiang, and Song 2011) techniques, the process of knowledge development knowledge for knowledge inte-gration and sharing is developed, as shown in Figure 3. The process model of product development knowledge forknowledge integration and sharing mainly are combined with four layers: the product development process, the knowl-edge sharing process, the knowledge operation process and operation supporting process. The product development pro-cess layer has five main phases: idea generation, concept design, preliminary design, detail design and technicalimplementation. The knowledge sharing process layer has three main phases: knowledge requirement establishment,knowledge matching and sharing and knowledge recommendation. There are six phases in the knowledge operation pro-cess: need definition, need dissolution, knowledge resource, knowledge integration, and knowledge sharing and productdevelopment knowledge recommendation. The operation supporting process layer comprises of the following phases:knowledge definition, knowledge classification, knowledge representation, integration ontology definition, ontologyschema definition, ontology mapping and integration, integration ontology establishment, problem description, knowl-edge query, knowledge learning, decision-making, problem-solving and knowledge matching.

Know-whatontology

Know-howontology

Know-whoontology

Know-whyontology

XML Topic Maps XML Topic Maps XML Topic Maps XML Topic Maps

Ontologylayer

XTMlayer

Resourcelayer

Knowledge object

Figure 2. The proposed model for product development knowledge representation.

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4.2.2 Ontology-based framework for product development knowledge integration and sharing

Based on the knowledge sharing process of product development, the ontology-based framework for product develop-ment knowledge integration and sharing is developed to support knowledge integration and sharing in each phase andactivity of product development. This designed framework comprises knowledge representation layer, knowledge classi-fication layer, knowledge integration layer and knowledge sharing layer. Each layer is defined as follows:

� Knowledge representation layerAn effective product development knowledge integration and sharing framework establishes a sharable knowl-edge representation method and model, records the linking address physical knowledge. The physical knowl-edge provides product development data, information, tangible and intangible knowledge.

� Knowledge classification layerAccording to the knowledge classification defined in Section 4.1, the product development knowledge ontologyis classified into four types: know-what ontology, know-why ontology, know-how ontology and know-whoontology. This represented knowledge ontology is mapped to the know-X ontology for knowledge integration.

� Knowledge integration layerUsing the knowledge integration method and mechanism, the represented knowledge ontologies are mappedand integrated into the knowledge integration ontology ‘Know-X ontology’ through the adaptors. Using theknow-X ontology, this knowledge integration ontology can connect physical knowledge address. Thus, productdevelopers can share their own product development knowledge with other knowledge owners in product devel-opment process to increase product value.

� Knowledge sharing layerProduct developers can retrieve knowledge from integrated product development knowledge according to theirknowledge demands. The primary process in knowledge sharing is as follows: problem description, knowledgequery, knowledge learning, decision-making and problem-solving. Knowledge searching identifies the most suit-able product development knowledge via knowledge similarity computations for all product developmentknowledge (Figure 4).

Knowledge Requirement Establishment

KnowledgeMmatching &

Sharing

Knowledgedefinition

Knowledgeclassification

Knowledgerepresentation

Knowledgeintegration

Knowledgesharing

Knowledgeresource

Needdefinition

Needdissolution

Integration ontologydefinition

OntologySchema

definition

Ontologymapping & integration

Problem description

Knowledgequery

Knowledgelearning

Decision making

Problemsolving

Integration ontology

establishment

Knowledgerecommendation

Product development knowledge

recommendation

Knowledgematching

Legend

Developmentalprocess

Mappingprocess

Se rvice sMark e tingProductionProduct De ve lopm e ntMark e t Surve yProduct Development

Process

Idea generation Concept design Preliminary design

Detail designTechnical

Implementation

KnowledgeSharing Process

KnowledgeOperation

Process

Operation Supporting

Process

Figure 3. Knowledge sharing process of product development.

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4.3 Product development knowledge integration and sharing method development based on ontology

To realise the knowledge integration and sharing for ontology-based product development knowledge, the integrationand sharing method for product development knowledge is developed in this section. This developmental processinvolves the establishment of knowledge integration ontology, development of selecting the target knowledge for knowl-edge query and design of a filtering method for supplied knowledge for developers.

4.3.1 Establishment of a knowledge integration ontology

The product development knowledge integration ontology is present in Figure 5, which encompasses development pro-cess, knowledge object and development object. The sub-concepts of these ontologies are defined as follows:

� Sub-concepts from the development process are combined with some important elements, which are processelement, design activity, design task, participant, design guide and guide model.

� Sub-concepts from the development object encompass structure, material, person, product, component, homepart, out part, standard part, external cooperation part, function and bill of the material.

� Sub-concepts from knowledge object consist of several ontology elements, which are mainly project, functions,structure, department and persons involved in the project. The relationship between properties is defined asshown in figure.

4.3.2 Development of selecting the target knowledge for knowledge query

After establishment of a knowledge integration ontology described in Section 4.3.1, an ontology-based search methodfor product development knowledge is designed that allows product developers to search for product developmentknowledge.

Know-what ontologyKnow-what ontologyKnow-what ontology

Knowledge integration

Request Response

Knowledge representation

Know-what ontology

Know-X ontology

Adaptor

Ontology mapping

Problemdescription

Knowledgequery

Knowledgelearning

Decisionmaking

Problemsolving

Administrators

Manage

Manage

Knowledge Sharing

Knowledge classification

Adaptor Adaptor Adaptor

Knowledge searching

Figure 4. Ontology-based framework for product development, knowledge integration and sharing.

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The calculation of the similarity between knowledge users and knowledge resources is based on the knowledgeontology. The keywords of knowledge requirement match with knowledge ontology’s attribute value. Traversing allknowledge resources, the similarities between knowledge requirement keywords and knowledge ontologies are calcu-lated one by one. Then the average value of the above results is derived to measure the similarity between them:

SimðR; SÞ ¼ a� TRSTR

� �þ b� TRS

TS

� �

where R and S denote the knowledge user and knowledge resource; TR denotes knowledge characteristics of knowledgerequirement set; TS denotes knowledge resource set; TXS denotes the similar characteristics set between knowledgerequirement and knowledge resource; a; bð0\a; b\1Þ denote the weight coefficient, set by users according to actualcondition.

Consequently, similarity matching for knowledge query is the sum of key attributes similarity as shown:

KSim ¼Xni¼1

Simðr; sÞ

where i denotes the attribute set of knowledge ontology.

4.3.3 Design of a filtering method for supplied knowledge for developers

For a product developer, this section addresses how to filter the supplied knowledge queried from knowledge resource.Figure 6 shows the query and filtering process based on ontology for product development, which includes the follow-ing steps: input knowledge requirement, filter the keywords, get all knowledge ontology attributes, calculate the key-words and attributes similarity, sum keywords and ontology attributes similarity, sort results based on their similarityand output knowledge.

When a product developer connects into the product development knowledge sharing network, some potentially use-ful knowledge resources are supplied to him. Then a filtering process will select some correlative knowledge resource,and the knowledge resource will be recommended to the product developer.

The criterion of some filtering is a function defined as FCðr; qÞ, which denotes the score of the knowledge resourceq as to the product developer r:

FCðr; qÞ ¼Pn

i¼1wi � Simðri; qiÞPni¼1Simðri; qiÞ

Knowledge_objects

Persons Departments Structures Functions Projects

Know-XDevelopment_

processesDevelopment_

obiects

is_owned_by

belong_to belong_to is_related_with belong_to

belong_to

has_structure

has_function

has_participate_in

Concept classification Object attribute Concept entity

Figure 5. Knowledge integration ontology.

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where wi denotes the score given by one as the important degree of knowledge ontology attribute; we could simplifythat process by assigning from 0 to 1 to that wi by knowledge user or supplier; Simðri; qiÞ denotes the similaritybetween knowledge resource q and product developer r.

5. An example of application in product development

Based on the proposed methods and techniques for knowledge integration and sharing for product development, a proto-type of knowledge integration and sharing mechanism is developed to support auto headlamp product development.

The headlamp is also a very personalised product. The headlamp is a complicated auto unit, and it is often difficultfor product developers to understand the problems and issues incurred during the usage of car headlamp. This casestudy will demonstrate how product developed knowledge integration and sharing method can help developers to obtainknowledge they required during product development stage. The structure of auto headlamp is shown in Figure 7 asfollows:

5.1 Establishment of knowledge representation model

The headlamp product development knowledge object ontology model is shown in Figure 8, which consists of fourkinds of knowledge ontology such as know-what knowledge, know-why knowledge, know-how knowledge and know-who knowledge. The sub-concepts of these knowledge ontologies are identified as follows:

� Sub-concepts from know-what consist of several ontology elements, which are mainly data properties, func-tions, features, plans and markets.

� Sub-concepts from know-why ontology consist of several ontology elements, which are mainly persons,resources, rules and projects.

� Sub-concepts from know-how ontology consist of several ontology elements, which are mainly data properties,functions, features, plans and markets.

� Sub-concepts from know-who consist of several ontology elements, which are mainly persons, department,workgroups, roles and projects.

According to the ontology developed above, the XTM layer establishes links between the knowledge resource andthe knowledge application. A part of prototype model can be seen in Figure 9. The development object is a panel ofpurfling assembly. According to the definition above, there are three layers about headlamp development knowledge rep-resentation model.

The resource layer is provided with a knowledge resource that contains a database of information system, Internet/Intranet web information and the participant’s form for completing the project. In the XTM layer, there are XTM topics

START

Input knowledge requirement

Filter the keywords

Get all knowledge ontology attributes

Calculate keywords and attributes similarity

Sum keywords and attributes similarity

Sort results based on their similarty

Output knowledge

END

Figure 6. Query and filtering process based on ontology for product development.

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and the relation between them. According to their attributes, there are different types of relationships between the XTMtopics. The XTM topic and XTM relation connect to knowledge resource through XTM link as shown in figure. Theontology layer provides a knowledge ontology which consists of design process ontology, design object ontology andknowledge object ontology. In Figure 9, it shows the know-how ontology, and also expresses the property of know-howontology. The ontology and ontology relation connect to XTM topics through ontology link as shown in figure.

5.2 Design of integration ontology for product development

The panel colour development knowledge integration ontology model is shown in Figure 10, which encompasses devel-opment process ‘preliminary design’, knowledge object ‘colour’ and development object ‘panel’. The sub-concept fromknowledge object is knowledge contents and resources for know-what, know-why, know-how and know-who. The sub-concept from development process is activities, participants, task, et al. The sub-concept from development object is theproduct or part name which is developed.

The knowledge integration ontology schema is used to build the product development knowledge maps to integrateand share knowledge. The schema is described as follows:

headlamp

lamp assembly

dimmer motor assembly

PES assembly

matched mirrorassembly

reflectorassembly

standard parts

harness assembly

lamp body

motor

bracket motor

bracket dimmer

lens

lens holder

mask assembly

PES reflector

matched mirror

purflingassembly

inner lens

reflector

connecting piece

rear cover assembly

breather cap

lamp holder

lamp bulb

purfling

panel

Figure 7. The structure tree of auto headlamp.

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� Product/part name: Expressing a product or part name which is developed.� Development process: Recording the stage for a product development activity. Its sub-concept is activity name,

participant name, task name, et al.

headlamp

Know-what Know-why Know-how Know-who

Features Plans

Markets

Persons Resources Rule Projects

Persons Projects

Persons Roles

Projects

is_owned_by

belong_

to

is_owned_by

belong_to

is_related_with

belong_to

belo

ng_t

o belong_tois_related_with

is_owned_by

belong_tobelong_to

is_related_with

belong_to

has_property

has_function

has_

feat

ure has_plan

is_related_to

StructuresDepartments

FunctionsFunctions

Data_properties

Departments

Workgroups

Figure 8. Headlamp product knowledge ontology.

Figure 9. Representation model for panel development knowledge.

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� Knowledge object: Recording the linking address of knowledge resource and knowledge content. This is themain part of knowledge integration ontology.

� Development object: Recording the development object information which is object name, product name andprocess name.

� Essential information: Presenting information related to a product or part, including function, input, output, con-straint and resource (Figure 11).

5.3 Method application of knowledge sharing for product development

When a product developer requests knowledge during the development of a product or a part, he connects into theknowledge sharing network, the first thing is to find some help form knowledge repository. There are defined knowledgeresources in knowledge repository. The similarities between product developer and knowledge ontology are calculated.Then the next step is to filter the supplied knowledge queried from knowledge resource. The top-five most similarknowledge resources are selected for product developer. The process of knowledge sharing for product development isshown in Figures 12–16.

(1) Parts of the headlamp product development knowledge are shown in Figure 12. There are eight topics inFigure 12 that include motorcycle type, material, CAD, 3D model, colour, structure design, surface and hard-ness. Then knowledge ontology is divided into four types: know-what, know-how, know-why and know-who.

(2) The headlamp product development knowledge integration ontology is shown in Figure 13. It describes therelated knowledge of the headlamp product development created by Protégé.

(3) In Figure 14, it presents the knowledge topic 5 and its similarity value from Figure 12 which consists of cate-gory knowledge, colour feature knowledge, colour suitability knowledge and file updater/creator.

(4) Finally, Figure 15 summarises the query and knowledge sharing result of product development and the relatedknowledge of the headlamp product development.

panelcolor_know-x

color

Knowledgeobject

Know-what

Know-why

Know-how

Know-who

Part_of

Part_of

Contains

Contains

Contains

Contains

preliminary design

activities participants task

panel

Part_of

Part_of

Is_a Is_a Is_a

Song

color design headlamp

designWu

Xu

Figure 10. The knowledge integration ontology for panel product development.

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6. Experiment

An experiment is needed to be designed to evaluate the method proposed in this paper. Zhen and Jiang’s experiment(Zhen, Jiang, and Song 2011), which is to evaluate the performance of the proposed active knowledge supply model fordistributed knowledge sharing in their paper greatly inspires the authors. They have made an excellent work. The exper-iment designed by the authors consists of defining and explaining of the data-set, metrics and methodologies, resultsand analysis from the experiment.

6.1 Data-set

The authors design some experiments based on data collected from a manufacturing enterprise in Shanghai, China. Thedata which is collected records 100 product development engineers’ knowledge browsing content tracks in two months.There are almost 20,000 knowledge resources in the knowledge repository in the centre server of the product develop-ment department. On a knowledge portal system, product development engineers share and query many knowledge con-tents in work day. The data-set consist of 53,624 tracking data records. And these records note which knowledge filehas been read by which user on which time. All the knowledge resources have a uniform presentation format describedin knowledge presentation section above. The uniform presentation format information for knowledge is one of basis forthis experiments’ implementation.

product/part name: panel

developmemtprocess

knowledge object

development object

essential information

Activities: color design

Participants: song,xu,wu

Task: headlamp design

Object name:panel

Product name: headlamp

Process name :preliminary design

Knowledge name: know-how

Knowledge content: CAD

Function: panel color design

Output: panel product model

Input: panel product model

Constraint: headlamp contracture

Resource: design repository

Relationship

is_part_of

belong_to

has_function

has_participant_in

Figure 11. The knowledge integration ontology schema.

Topic1: motorcycle type motorcycle typeinformation

target customerinformation

Topic2: material panel material information physical property knowledge pressure rules knowledge material experts

Topic3: CAD technical parameters modeling knowledge modeling skill knowledge file updater/creator

Topic4: 3D model technical parameters modeling knowledge modeling skill knowledge file updater/creator

Topic5: color category knowledge color feature knowledge color fitness knowledge file updater/creator

Topic6: structural design panel structural knowledge external dimensionknowledge

pressure rules knowledge designers/updater

Topic7: surface pattern type knowledge smoothness knowledge surface curve knowledge designers/updater

Topic8: hardness hardness knowledge hardness function knowledge hardness rulesknowledge

file updater/creator

CategoriesTopic

Know-what knowledge know-why knowledge know-how knowledge know-who knowledge

Figure 12. Headlamp product development knowledge.

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6.2 Metrics and methodology

The collected 60 days’ data-set is divided into two parts: matching set and testing set. The matching set contains the ear-lier 40 days’ data records, which was used to select similar colleagues for each product development engineer; and

Figure 13. Knowledge integration ontology of headlamp product development.

category knowledge color feature knowledge color suitability knowledge file updater/creator

pressure, time curve material property knowledge pressure rules knowledge material experts

forming process knowledge physical size formula time rules knowledge file updater/creator

fuzzy membership degree length calculation formula transparency knowledge file updater/creator

physical parameter knowledge thickness calculation formula dustproof knowledge file updater/creator

mechanical properties table hardness calculation formula high temperature rules designers/updater

FMEA knowledge Cav No table surface curve knowledge designers/updater

material PTV curve physical dimension knowledge low temperature rules designers/updater

Know-what knowledge know-why knowledge know-how knowledge know-who knowledge

category knowledge color feature knowledge color suitability knowledge file updater/creator0.684 0 0.698 00 0.353 0 00 0 0 0.8250 0.463 0.345 00.267 0 0.58 0.4540 0 0.589 0.8960.12 0 0.577 0.832

Know-what knowledge know-why knowledge know-how knowledge know-who knowledge

Topic 5:color

Similarity value

Figure 14. Knowledge ontology mapping result for headlamp colour development.

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testing set contains the latter 20 days’ data records, in which if a product development engineer has knowledge in read-ing track records, it would be stored as the engineer’s connection in the knowledge sharing network. The results ofknowledge supplied to user will be compared with the user knowledge browsing track records on that day. If the prod-uct development engineer i has knowledge track records in j days during the latter 20 days (testing period, j� 20). Inthese j days, we can obtain j sets of supplied or recommended knowledge, which are denoted by Rm;im 2 ½1; j�. Theactual track records for product development engineer i are denoted by Tm;im 2 ½1; j�. For the product development engi-neer i, the precision based on the method proposed by Zhen et al. is defined as follows (Zhen, Jiang, and Song 2011):

Pi ¼Sj

m¼1 Rm;i

� � \ Sjm¼1 Tm;i

� ��� ��Sjm¼1 Rm;i

�� ��In this formula, the numerator denotes the number of common data units in both the sets:

Sjm¼1 Rm;i and

Sjm¼1 Tm;i.

The denominator denotes the number of data units contained in the setSj

m¼1 Rm;i. The final evaluating indicator ‘Preci-

sion’ is derived by the average of Pi, P ¼PN

i¼1Pi

N , where N is the number of product development engineer in this exper-iments and N ¼ 100.

Obviously, a product development engineer’s knowledge browse data is more than knowledge recommendation data.In another words, the set T is larger than the set R, which makes recall value very small. So the recall is not containedin this experiment.

6.3 Results and analysis

The authors design the size of team varying from 5 to 50 in this experiment, and the queue length varying from 10 to40. From this experiment, the sensitivity for team size could be analysed. From Figure 16, it could be concluded thatthe precision enlarges with the growing team size and tends to a steady value when the size is larger than 20. Theauthors set 20 as a proper size of the team. Because that too large of the team size may have too much irrelevantknowledge for product development engineers. Too large of the team size will damage knowledge sharing effectiveness.

In Figure 16, there are four curves displaying four queue lengths from 10 to 40, in which the influence of the queuelength on the final results can be reflected. From Figure 16, we can know that the quality of knowledge sharing

Figure 15. Related knowledge of the product development knowledge.

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improves visibly as the queue length increases. But we can also know from Figure 16 that when queue length exceeds30, the improvement effect slows down and even has a worse trend.

Actually, the authors propose a knowledge sharing model that is based on product development engineers’ personalknowledge repositories in product development team. However, the traditional knowledge sharing environment is basedon the centralised knowledge repository, in which knowledge resources are distributed to product development engineersaccording to their demands. Then the authors design some experiments to compare the personal knowledge repositories-based knowledge sharing model with the knowledge distribution model based on the centralised knowledge repository.

The proposed knowledge sharing model in this paper and the traditional model are based on same data-set. In thisexperiment, the matching set of the data is use to generate the demands of product development engineers, then theselected knowledge is sent to some product development engineers. The precision would be calculated to compare thesent knowledge to the knowledge actually read by the product development engineers in the testing data-set generatedin testing period. The final evaluating indicator ‘Precision’ is calculated to measure the quality for method proposed inthis paper and the traditional knowledge sharing method. The size of team is set from 5 to 50.

The results of the comparison experiments are shown in Figure 17. From Figure 17, we can see that the knowledgesharing model proposed in this paper has an advantage over the traditional centralised knowledge sharing mode.

The results validate the efficiency of the proposed knowledge sharing systems. However, the experiment in thispaper is a simulation test. It doesn’t build on the base of product development engineers’ real routines. From this exper-iment results, the knowledge sharing quality could be analysed under different parameters.

Figure 16. The results under different sizes of teams.

Figure 17. The comparison between the proposed method and the traditional method.

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7. Conclusion and future perspective

This study develops knowledge integration and sharing approach for complex product development that effectively inte-grates product development knowledge distributed among various information systems and product developers with theability to share product development knowledge. The detailed results and contributions of this study are as follows:

(1) This study establishes product development knowledge integration ontology. Additionally, the ontologyschema is also designed that includes product/part name, development process, knowledge object, develop-ment object, essential information and relationship. The core techniques involved in the integration and shar-ing method designed for product development knowledge include development of selecting the targetknowledge for knowledge query and design of a filtering method for supplied knowledge for developers.These techniques are developed to achieve ontology-based knowledge integration and sharing during productdevelopment.

(2) Based on the proposed integration and sharing methods for product development knowledge, the knowledgeintegration and sharing method for product development was implemented to demonstrate the feasibility ofthe proposed methods.

However, there are still some limitations for the current model and methods:

(1) The method proposed in this paper lies in that all engineers in enterprise are willing to share their knowledgewith each other. In reality, lots of engineers want to receive more knowledge from others than to share theirknowledge with others. Then this knowledge sharing model will not work well. So, the enterprise should toestablish some incentive mechanisms embedded into this model to improve its practicality.

(2) This study only considers the similarity relationship among engineers. Actually, the relationships betweenengineers are very complex. In order to make the knowledge sharing network more intelligent, we shouldconsider some semantic relationships between engineers.

(3) In addition, the scale of the experiments in this paper is not large enough. The number of product develop-ment engineers and knowledge resources that are involved in this study are a bit small.

Future work of the proposed approach include: to develop knowledge configuration and sharing mechanism accord-ing to user requirement, to construct knowledge recommendation mechanism based on product development process.Finally, detailed empirical studies for various types of product development projects are sought in order to further vali-date the representation model proposed in this paper.

AcknowledgementsThe author would like to thank Shanghai Research Center for industrial Informatics for the funding support to this research.

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