Joseph P Zammit
email: j.p.zammit@greenwich.ac.uk

James Gao
email: j.gao@greenwich.ac.uk

Richard Evans
email: r.evans@westminster.ac.uk

A framework to capture and share knowledge using storytelling and video sharing in global product development

Keywords: Knowledge Management, Product Development, Product Validation and Testing, Social Media Tools, Tacit Knowledge

In global engineering enterprises, information and knowledge sharing are critical factors that can determine a project's success. This statement is widely acknowledged in published literature. However, according to some academics, tacit knowledge is derived from a person's lifetime of experience, practice, perception and learning, which makes it hard to capture and document in order to be shared. This project investigates if social media tools can be used to improve and enable tacit knowledge sharing within a global engineering enterprise. This paper first provides a brief background of the subject area, followed by an explanation of the industrial investigation, from which the proposed knowledge framework to improve tacit knowledge sharing is presented. This project's main focus is on the improvement of collaboration and knowledge sharing amongst product development engineers in order to improve the whole product development cycle.

Introduction

Knowledge is the key to innovation and staying competitive in today's engineering world. It is a crucial asset for organisations that enables them to gain a sustainable competitive edge over their competitors [START_REF] Grant | Prospering in dynamically-competitive environments: Organizational capability as knowledge integration[END_REF]. By improving and creating new ways in which enterprise knowledge is captured and shared amongst engineering teams, will determine if they are capitalizing on this valuable, readily-available company resource. Organisational competitiveness is rooted in the mobility of knowledge that is realized through knowledge sharing and knowledge transfer. It has been identified in literature that knowledge sharing provides individuals, teams and organisations with the opportunity to improve their work performance as well as create new and innovative ideas [START_REF] Cummings | Work groups, structural diversity, and knowledge sharing in a global organization[END_REF]. This clearly shows that sharing knowledge is a social, interactive, and complex process that includes tacit and explicit knowledge [START_REF] Polanyi | The Tacit Dimension[END_REF]. The challenges for knowledge management initiatives are finding solutions to people-centric problems, such as motivations and personality factors, and creating organisational antecedents to ensure a smooth knowledge flow [START_REF] Krogh | Managing knowledge: perspectives on cooperation and competition[END_REF].

Innovation consists of successfully implanting creative ideas within an organisation [START_REF] Myers | Successful industrial innovations: A study of factors underlying innovation in selected firms[END_REF] and is, therefore, closely related to organisational learning. Innovation is conceived as an individual and collective learning process that aims to find new ways of solving problems [START_REF] Alegre | Assessing the impact of organizational learning capability on product innovation performance: An empirical test[END_REF]. The reason why knowledge sharing receives considerable attention [START_REF] Eisenhardt | Knowledge-based view: A new theory of strategy[END_REF], is that it is vital for innovation, organisational learning, the development of new skills and capabilities, increased productivity and maintaining a competitive advantage [START_REF] Mooradian | Who trusts? Personality, trust and knowledge sharing[END_REF][START_REF] Krogh | Care in Knowledge creation[END_REF].

This paper presents ongoing work to develop a knowledge sharing environment within a product development testing facility using advanced Web tools. The project is in collaboration with a global power generation company and the objective of the project is to provide a knowledge sharing environment that enables knowledge to be captured, documented, created and shared using a combination of Information and Communication Technologies (ICT), such as rich multimedia content, social media and video sharing. The developed framework will be driven by the knowledge user, rather than knowledge administrators, based on the users' day to day knowledge requirements. The framework is aimed to assist in reducing product development time and costs by avoiding task repetition and reinventing the wheel during new product development projects.

Research Background

Knowledge Management can be defined as "the ability to harness and build upon an organisation's intellectual capital" [START_REF] Drucker | The New Realities[END_REF]. With the current economic climate, companies need to know what they know, and must use this knowledge effectively.

The size and dispersion of global organisations make it especially difficult to locate existing knowledge and get it to where it is needed. According to Davenport and Prusak [START_REF] Davenport | Working Knowledge: How Organizations Manage what They Know[END_REF], the maximum size of an organisation, in which people know one another well enough to have a reliable grasp of collective organizational knowledge, is two hundred. The vast amount of knowledge found in a global enterprise which has offices and plants spread around the globe is enormous; taping in to that pool of knowledge is a problem due to the sheer size of it. Corporate knowledge only becomes of value if people in the organisation can gain access to it. If there isn't a KM system available, employees would make do with what they already know or the knowledge that is most easily available. This knowledge could be of good quality, but in today's market, sometimes good quality is not good enough [START_REF] Shani | Knowledge management and new product development: a study of two companies[END_REF][START_REF] Ramesh | Supporting Collaborative Process Knowledge Management in New Product Development Teams[END_REF]. A lot of companies can argue that KM systems costs a lot of money and the effort to setup and maintain is labour intensive. However, knowledge can provide a sustainable advantage to a company. Eventually, competitors can almost always match the quality and price of the market leader's current product or service. By the time this happens, the knowledge rich and good knowledge managing company will have moved on to a new level of quality, creativity and/or efficiency. The knowledge advantage is sustainable because it generates increased returns and continuing advancement [START_REF] Davenport | Working Knowledge: How Organizations Manage what They Know[END_REF]. Successfully embedded KM systems pay for themselves by creating new innovative ideas which are transformed into products, services and sales for the company.

The difficulty with tacit knowledge is that it is derived from a person's lifetime of experience, practice, perception and learning [START_REF] Polanyi | The Tacit Dimension[END_REF]. This type of knowledge is highly abstract and closely relates to 'know-how' [START_REF] Grant | Toward a Knowledge-based Theory of the Firm[END_REF]. Thus, one may acquire tacit knowledge in one context and apply and stimulate this knowledge in another context [START_REF] Burrows | Common Knowledge: How Companies Thrive On Sharing What They Know[END_REF][START_REF] Nonaka | The Knowledge-creating theory revisited: Knowledge creation as asynthesizing process[END_REF].

Learning Methods

Learning is divided into two categories: Active and Passive Learning [START_REF] Koners | Managers' perceptions of learning in new product development[END_REF]. Active learning emphasises on the intrinsic motivation and self-sponsored curiosity of the learner who fashions content and is actively involved in its formation. Active learning shifts the focus of content structuring from the teacher to the learner. By being actively involved in the shaping of content, the learner gains a greater understanding of the information. Active learning is normally achieved by methods which reinforce knowledge; this can be achieved through discussion of the subject matter with peers or supervisors, practicing the knowledge you have gained or by teaching it to others within a group or team. These methods allow a person to gain a better understanding of the subject matter and, from the interaction with others, new ideas on the subject can be developed.

The opposite of active learning is passive learning. Passive learning focuses on the instructor, not the student. The standard teaching method used is the traditional lecture, whereby students are in effect bench-bound listeners, passively consuming the content presented by the instructor, according to the structure that he or she created [START_REF] Koners | Managers' perceptions of learning in new product development[END_REF]. This approach is most effective to increase knowledge and skills that do not involve interaction with others [START_REF] Mailick | Learning Theory in the Practice of Management Development: Evolution and Applications[END_REF]. However, as the name implies, 'passive' knowledge is one which is transferred to the student only if they are willing to learn. Fig. 1 shows the learning pyramid which illustrates the order of the different learning mediums and their effectiveness.

Fig. 1. The learning pyramid [19]

As anticipated, passive techniques are not as effective as discussing a topic or teaching a topic to peers, because passive learning, for it to work, needs the student to engage with the material, otherwise he/she won't gain anything from the lecture or the book which they are reading. While active learning, if the student needs to teach a topic to his/her peers, they will make extra effort to understand the subject matter in order for him/her to convey what they have learned.

An antidote for learning is to engage learners in active, constructive, intentional, complex, cooperative and reflective learning activities [START_REF] Jonassen | Constructivist learning environments on the web: engaging students in meaningful learning[END_REF]. These are the main goals of having a constructive learning environment. Constructive learning emphasizes the learning process, and the learner's thinking is encouraged and nurtured. The student's acquisition of knowledge is an outcome of the process focused on thinking, discovery and reflection [START_REF] Raines | An innovation to facilitate student engagement and learning: Crossword puzzles in the classroom[END_REF], making it a unique experience to each one of us.

Cooperative learning is a teaching method whereby students working in small groups to help one another learn academic materials. This methods provides a sense of individual accountability and interpersonal communications, which provides a deeper learning experience [START_REF] Raines | An innovation to facilitate student engagement and learning: Crossword puzzles in the classroom[END_REF]. Research has shown that these small groups produce higher achievement and healthier achievements than with competitive or individual experiences [START_REF] Johnson | What Makes Cooperative Learning Work[END_REF]. Electronic learning, as a concept, is associated with consistently higher levels of student satisfaction but it is generally accepted that online learning works best when blended with more traditional learning techniques, rather than trying to replace them [START_REF] Chumley-Jones | Web-based learning: Sound educational method or hype? A review of the evaluation literature[END_REF].

Advanced Web and Social Media Tools

Today, Web 2.0 and social media tools are widely used in our daily lives to share and communicate with each another, with tools such as Facebook and Twitter being readily available. These tools have emerged as main stream communication channels for people to communicate and share their daily experiences all over the world like never before. They have, however, changed the way our planet communicates. Macaskill and Owen [START_REF] Macaskill | Web 2.0 to go[END_REF] defined Web 2.0 as a 'web-based platform which allows users to gain access, contribute, describe, harvest, tag, annotate and bookmark Web mediated contents in various formats, such as text, video, audio, pictures and graphs [START_REF] Macaskill | Web 2.0 to go[END_REF]. Stuart [START_REF] Moron-Garcia | Using virtual learning environments: lecturers' conceptions of teaching and the move to student-centred learning[END_REF] provided a more precise definition of Web 2.0, stating that it is web sites which people can share content on. Web 2.0 is a vast improvement from Web 1.0 which only conveyed static information. With Web 1.0, only web programmers were able to modify and post contents. In contrast, with Web 2.0, anybody with minimal ICT skills can contribute and share their information [START_REF] Evans | Using Web 2.0-based groupware to facilitate collaborative design in engineering education scheme projects[END_REF].

According to Moron-Garcia [START_REF] Moron-Garcia | Using virtual learning environments: lecturers' conceptions of teaching and the move to student-centred learning[END_REF], the use of web-based technologies can facilitate the creation of student-centred learning environments. Learning environments, designed with reference to constructivist theories of learning, will embed in students the critical and cognitive skills that higher education aims to develop [START_REF] Moron-Garcia | Using virtual learning environments: lecturers' conceptions of teaching and the move to student-centred learning[END_REF][START_REF] Jonassen | A manifesto for a constructivist approach to uses of technology in higher education[END_REF]. Elearning, as a concept, is associated with consistently higher levels of student satisfaction. However, it is generally accepted that online learning works best when it is blended with traditional learning techniques, rather than trying to replace them [START_REF] Chumley-Jones | Web-based learning: Sound educational method or hype? A review of the evaluation literature[END_REF].

Video Sharing and Storytelling

It has previously been mentioned that tacit knowledge is difficult to capture and share, due to the personal understanding of the subject matter [START_REF] Nonaka | The Knowledge-creating company[END_REF]. Only tacit knowledge that can be transformed into explicit knowledge can be successfully shared. As suggested by Hislop [START_REF] Zammit | A knowledge sharing framework for improving the testing processes in global product development[END_REF], tacit knowledge can be captured and shared by 'direct communication among individuals' by means of 1) stories, 2) observing others, and 3) learning by doing within a community.

Reamy [START_REF] Zammit | Investigating the use of social media in improving knowledge management within a collaborative product development and testing environments[END_REF] suggested that storytelling is the best way to transfer tacit knowledge, being that you are able to convey information and context in a form that is easy for other people to understand. According to LeBlanc and Hogg [START_REF] Leblanc | Storytelling in knowledge management: an effective tool for uncovering tacit knowledge[END_REF], stories make information meaningful, making tacit knowledge more explicit and allowing information to be organised into learnable chunks. This methodology was also suggested by Martin-Niemi [START_REF] Oliver | How to develop knowledge culture in organizations? A multiple case study of large distributed organizations[END_REF] who utilised storytelling with new generation Web 2.0 technologies, providing an individualized and customizable user experience which included virtual social interactions, shared collaborative portals and communications tools, but it was not put into action.

One medium to capture and share storytelling, as part of a Web 2.0 environment, is video sharing. Balcikanli [START_REF] Mueller | A specific knowledge culture: Cultural antecedents for knowledge sharing between project teams[END_REF] concluded that YouTube, a video sharing website, can be integrated as an effective online tool for learning due to its ease of use and its connection to an abundance of video clips that not only teach, but also demonstrate the cultural context in which the material can be properly applied.

Industrial Investigation

An in-depth industrial investigation was carried out with an industrial partner operating in the manufacturing industry, through observational and hands-on study, including a questionnaire investigation with engineering staff at different levels of the organisation. This provided an overview of management and employee views [START_REF] Zammit | A knowledge sharing framework for improving the testing processes in global product development[END_REF].

The main outcome from the initial investigation was to explore and develop a cost effective knowledge sharing tool that allows for the capture of existing company knowledge and for it to be disseminated throughout entire engineering teams in order to improve employee understanding of in-house engineering practices and avoid reinventing the wheel when knowledge is already available but not properly documented and ready for reuse.

The knowledge framework, proposed in this paper, should provide a theoretical method that gives users the opportunity to easily capture and document the knowledge that they have acquired during their years of service. The framework provides the possibility to store this knowledge so that it can be easily searched, shared and disseminated, both locally and globally, throughout the organisation, using knowledge mediums that can deliver knowledge quickly and provide high learning impact to the knowledge receiver. The framework is also cost effective as it reduces the amount of administrative effort required to manage knowledge and minimize the cost of knowledge capture; this makes the knowledge sharing system more attractive to business.

Proposed Knowledge Framework

The proposed knowledge framework to support the product development team and its stakeholders, is shown in Fig. 2. The diagram represents the proposed knowledge cycle required to capture and share knowledge, but also to create new knowledge and build upon pre-existing company knowledge.

Start End

Fig. 2. The Knowledge Framework to Support the Product Development Team

The framework is made up of four main quadrants: Query, Identification, Capture and Sharing, with each quadrant divided into a further two sections. The cycle begins with the knowledge query quadrant where a user submits a question, from which they will need to search the knowledge database for an answer to their question. If an answer is not found the user moves to the next quadrant, knowledge identification, which contains the identification of the knowledge gap. They then stipulate the knowledge requirement and request it through the system for a knowledge expert to complete.

In the third quadrant, knowledge capture involves the evaluation of the knowledge request and the selection of a knowledge expert who could contribute towards the new knowledge contribution. The selection criteria of the knowledge expert is categorised in to three fields: (1) having the perfect match between the knowledge expert and the knowledge requested, (2) a knowledge expert in a similar field to the knowledge requested, and (3) enthusiastic knowledge contributor that is willing to learn new knowledge in order to contribute towards a knowledge request. Once the knowledge is captured, it is stored on an electronic database. The final quadrant of the framework is that of knowledge sharing, which is divided into sharing and knowledge discussions. Knowledge sharing consists of a searchable database from which knowledge can be identified and accessed for learning. At this point, the user has the opportunity to question or even challenge the available knowledge through the discussion facility; this brings us back to the start of the cycle where a user can create new knowledge by submitting further knowledge questions that need to be addressed through another knowledge cycle. Each knowledge cycle is aimed at creating both the database of knowledge and, at the same time, the autonomy of the system determining the knowledge direction depending on end user interests and knowledge needs.

The proposed framework targets the knowledge experts to create the knowledge contribution, removing the need of additional personnel / administrators to support and create the system content and, therefore, reducing the cost of its management.

4.1

Selected medium for knowledge capturing and sharing

The medium selected to capture and share knowledge needed to be in a format that is easy to use and one which provides the ability to capture complex content. Knowledge should be quick to create, absorb and allow for different technical levels of competence to understand and use with minimal training. The medium selected was that of social media and video sharing. The main motivation in using these tools was due to its mass popularity, which in the last decade, has seen social media and video sharing explode exponentially into our everyday lives. It is also available via multiple routes, including computers, tablets, and smart phones, making it an ideal tool to be adopted, while also providing a guarantee of user acceptance due to its preexisting familiarity with the end user; this is also supported from a previous end user investigation carried out by the authors [START_REF] Zammit | Investigating the use of social media in improving knowledge management within a collaborative product development and testing environments[END_REF]. The social media techniques are also being used to generate knowledge discussions from the content created which it is hoped will also identify new knowledge gaps and create new knowledge and content.

The main benefits of the framework are:

• People contributing to the Knowledge base system will learn more about the subject, by reinforcing their own knowledge;

• Knowledge will be documented and, therefore, available to other staff to learn from and can also be used for training existing or new staff;

• The social discussions / comments will generate further clarifications and also further knowledge to both the sender and receiver;

• Generation of new ideas; and

• The Social discussions will promote teamwork, with the added advantage of improving social interaction between different departments.

The idea to use rich media and video sharing content, as a mean for knowledge transfer, has already been used by universities to some degree as a method to supplement the student learning processes [START_REF] Clifton | Can YouTube enhance student nurse learning?[END_REF]. However, it appears that universities generally rely either on professional media companies to develop the knowledge content or rely on readily available content found on the internet. There is a gap in the literature on knowledge content created by the actual knowledge expert. In today's high-tech and socially connected world, people have been extensively exposed to digital cameras through use of their smart phones and when creating media content for social media platforms. Therefore, the proposed framework will allow the authors to investigate if this social phenomena can be exploited by employees with readily available skill sets, to capture knowledge using rich media content and determine the effort, effectiveness and quality of the captured knowledge. To develop such a framework a tangible tool was required, which employed the following components:

• A knowledge repository that provides easy access to corporate knowledge;

• A process to request and manage, user knowledge requests;

• A formal methodology to capture and compose knowledge contributions by knowledge experts;

• Guidelines of the developed knowledge framework for use for further system development and replication; and

• Training material for end-users both in text format and rich media format using the develop methodology to guide users in the use of the developed tool.

Conclusions

In today's globally dispersed marketplace, time is a luxury that top companies are scarce of, with each activity taking time out of a project development cycle [START_REF] Oliver | How to develop knowledge culture in organizations? A multiple case study of large distributed organizations[END_REF]. Companies often face the problem that knowledge sharing activities are usually not an integral part of an official job description and, therefore, no time resource is allocated for this kind of activity. Furthermore, project teams suffer from time pressures to reach project goals and consequently do not have free time to create new knowledge or share it [START_REF] Mueller | A specific knowledge culture: Cultural antecedents for knowledge sharing between project teams[END_REF]. This is for both capturing knowledge and looking through readily available knowledge. The principle aim of the developed framework is to utilize social media tools, which are commonly used in our everyday lives, to simplify both the capture and sharing of enterprise knowledge. The framework is now being developed into a tool which will be validated by means of a case study in conjunction with the industrial partner, and will answer the research question of: "Can social media tools be used effectively, at a relatively cheap cost, for companies to capture and share tacit knowledge inside their employee's minds?" Initial feedback from knowledge contributors participating in the case study have provided positive feedback to both the developed framework and the ongoing development of the tool, which aids them in their task of capturing knowledge.


P P Wang

X G Ming

M K Zheng

A Framework of Value Creation for Industrial Product-service

Keywords: Product-service System, value network, value creation, serviceoriented manufacturing

With the increase of service profits, traditional manufacturing enterprises are transforming into providing Product-service System (PSS) which is a new product pattern and manufacturing paradigm. In order to respond to the transformation, this paper proposes the concept of productservice value creation as the value source of PSS. Firstly, this paper proposed the concept of product-service value creation network in order to reflect the complex nonlinear interaction of different value individuals. And the productservice value creation system is analyzed based on value network. Secondly, this paper proposed the product-service value creation process which includes value identification, value proposal, value delivery, and value evaluation. These four steps compose the close-loop of product-service value creation. The study on the product-service value creation lays a basis for further development and application of PSS.

Introduction

Since the early 1990s, the driver in our economy has been changing from production of material goods to product-service offers based on knowledge and information [START_REF] Roy | Product-service systems[END_REF] . It has become an important trend in the manufacturing industry that service is used to enhance the competitiveness of businesses as well as an important source of values. As a response to this trend, more and more traditional manufacturing enterprises are transforming into providing Product-service System (PSS) which is a new product pattern and manufacturing paradigm [START_REF] Gao | Service-oriented manufacturing: a new product pattern and manufacturing paradigm[END_REF] . In the mode of PSS, manufacturers provide producer services on process level mutually for cooperative production through integration of services and manufacturing; tangible artifacts and intangible services are integrated to provide a comprehensive solution for customers [START_REF] Wang | Research on industrial product-service configuration driven by value demands based on ontology modeling[END_REF] . Different from traditional manufacturing, the production process of service needs the participation of customers. And the value creation of PSS depends on the close cooperation of stakeholders [START_REF] Heskett | The service profit chain: How leading companies link profit and growth to loyalty, satisfaction, and value[END_REF] . So, the value source of PSS is the product-service value creation among stakeholders of PSS [START_REF] Bovet | Value nets: Breaking the supply chain to unlock hidden profits[END_REF] . However, there is less research on this topic, in fact only some application on a small scale [START_REF] Wang | Status review and research strategies on product-service systems[END_REF] . So, this paper will study on product-service value creation process based on value creation network, system, and mode. In this paper, product-service means industrial service portfolio which is derived from physical products and used to meet the value demands of customers.

Model of product-service value creation 2.1 Value creation Network

This paper proposed the concept of product-service value creation network in order to reflect the complex nonlinear interaction of different value individuals in the context of PSS. The value creation network is constituted by PSS clusters (realizing scale economy and circular economy) around one or several core business under diffusion effect. The stakeholders and network flows of value creation network could be described in figure 1.

Fig. 1. Product-service value creation network

The value creation network should be interpreted as a value creation alliance with the organization principle of value creation. Its complexity depends on both the number of stakeholders and the service delivery process. The value in network could be defined as the contribution of all stakeholders, including wealth, utility, benefits and rewards. It evolves constantly along with the changes of stakeholders' status, such as priority sequence, viewing angle, willingness to pay, and time range.

Product-service value network is a value creation and management system composed of basic elements such as resource, activity, institution, rule, information, market, relation and so on under the background of service economy. It has the capability of self-regulation and dynamic matching. Stakeholders in different links of value chain could realize continued value increment through value transmission mechanism and network rules. Value network is an open group based on value creation which could provide customized value combination and respond to customer demands quickly by integrated operation.

Value creation System

Modern enterprises cannot dominate the whole value chain and should improve core competitiveness by outsourcing non-core business. Integration of product and service makes value chain of manufacturing become complex and evolve into reticular. Enterprises' values are determined by final customers and delivered in the value networks.

Value of product-service comes from the customer's willingness to pay for service which is different from traditional value realization based on product delivery. The product-service value creation depends on the closely relationship with customers, such as service contact of product lifecycle. It has been found that value obtained by technology innovation or increased production is limited without taking the customer value as the core. So the value innovation of PSS is a new strategic approach of creating Blue Ocean and breaking through development bottleneck for manufacturers.

Fig. 2. Product-service value creation system

Service value creation reflects in constructing service system through integrating service resource dynamically and transform the service system into value co-create network composed by people, technology, and organization. In the context of PSS, manufacturer should not be treated in isolation because the value network is composed by supplier, customer, competitor, stockholders and partners as shown in figure 2. The relationships sustain the network across the industry and even national boundaries. The customer demands could transfer in the value network and available for every participant. The value network could bring required product and service to customers accurately through abandoning the activities which is not conductive to increasing customer value. So, value creation mechanism will be formed in order to adjust to dynamic value network and service system. The stakeholders could cultivate value creation capability expected by customers and transform customer knowledge into competitive advantages. The ultimate goal of PSS is providing perfect service experience and sustainable service value to customers circularly through four steps of value creation which will be described in detail in next section.

Process of Product-service Value Creation

Based on the above discussion, this paper proposes the value creation process which includes four steps and three cycles. The four steps are: value identification, value proposition, value delivery, and value evaluation. And the three cycles are: value creation, meet demands, and value realization as shown in figure 3. These three cycles reflect the trend of turning from the virtual to reality. The value of services should be customer perceived value which depends on the subjective evaluation from customers. In order to maximize customer value, the product-service value should be defined according to the most accurate value demands from customers. So this paper mining customer demands from three layers: target layer, result layer, and attribute layer as shown in figure 4. The target layer is the final goal of customers; the result layer is the service result of product-service; the attribute layer is the attributes of product-service. The target layer defines maximize customer perceived gains and minimize customer perceived losses; the result layer defines appropriate function combination of product-service; the attribute layer defines the reasonable process arrangement of product-service. Based on the value demands identification from customer, the product-service value could be defined from six dimensions according to SERVQUAL model as shown in table 1.

Value Proposition

The value demands of customers get more services into value chain of traditional manufacturers. With the rise of service, there are more and more value-added parts in value chain. The value chain needs integration and optimization in order to provide more values for customers. So the product-service scheme should be configured according to value demands and value chain extension as shown in figure 5.

Value Chain Extension Value Cocreation Network

Target Layer

Result Layer Function Configuration

Attribute Layer Process Configuration

Product-service Scheme

Blueprint of Product-service

Decision on Product-service Scheme

Fig. 5. Product-service value proposition process

Manufacturers integrate and cultivate service capability through service innovation based on optimized value chain. Figure 6 shows two typical roads of product-service extension. The first way is to transform product-oriented service to customer-oriented service which emphasizes improving customer value. And the improvement of product efficiency and effectiveness would be reflected within the customer process. The second way is to transform transaction-based service to relationship-based service by enhancing service innovation.

Fig. 6. Spectrum of Product-service

With enough service capability, manufacturers have to propose product-service scheme according to value demands of customers. Modular method is suitable for the configuration of product-service scheme which could be provided to customers in the form of customization-oriented menu. However, different from physical products, service is a set of continuous processes. So service modules could be divided into functional modules and process modules. The functional modules are configured according to the result layer of customer demands. And the process modules are configured according to the attribute layer of customer demands.

Value Delivery

The value delivery network should be built before product-service delivery as shown in figure 7. The value delivery network could be divided into service network, relations network, trade network, and knowledge network according to productservice value creation network. In service network, service level is the network flow which is a key index evaluating service behavior among enterprises. The higher the service level is, the higher the heterogeneous is. In relation network, relation level is the network flow which is a key index affecting corporate business practices such as business concession, membership system, public praise, reliance, friendship, and so on. In trade network, production level is the network flow which is a comprehensive reflection of various factors such as production technology, production efficiency, added value of service, and so on. In knowledge network, knowledge communication level is the network flow which is the reflection of knowledge kinds, quantity, integrity, and so on.

Different from physical products, product-service could be changed and optimized in the delivery process (service process). In order to maximize the value of productservice, the product-service scheme should be optimized real-timely during the service delivery. For example, the service demands described by customers are not exactly the value demands of customers which are usually mined during service process. Besides, the service encounter and service process could be optimized along with the improvement of relation level.

Value Evaluation

The value evaluation of product-service value creation includes two parts: performance evaluation of product-service and ability evaluation of value creation. The first part focuses on the quality of product-service. This paper evaluates productservice from two perspectives: service function and service process as shown in figure 8. The evaluation indexes of service function includes service resource(equipment, capability, and knowledge), service recovery (remedial measure and speed), service level (professional level, advanced level, customization level), service reliable (accessible, sustainable, and flexible), service contract (service price and qualification), service guarantee (preventive, active and supportive); the evaluation indexes of service process includes service response (response mode, constraint, and speed), service operation (continuity, rapid, and convenient), service manifestation (behavior, environment, encounter), service participation (participation style and extent), service personal (personal quality and ability), and service feedback (communication, complaint, and suggestion).

The second part focuses on the realization degree of value needs from customers. This paper evaluates the ability of value creation from three layers: target layer, result layer, and attribute layer. These three layers are corresponding to the layers of customer demands. The target layer evaluates product-service value realization and meeting customer demands; the result layer evaluates customer satisfaction, customer loyalty, financial performance, and product-service performance; the attribute layer evaluates detailed contents of result layer. And improvement suggestion of value creation capability could be proposed through evaluation and analysis of three layers. The object of case study is the customer service department of a civil aircraft manufacturer in China. As we all know, aircraft is one of the most complex products. Although the revenue share of after-sales market is less than 25% in aviation industry, the profit contribution can reach 40-70%, or even higher. Now the international large aircraft manufacturers have been trying to extend value chain, improving core competitiveness, and turning into integrated service providers. This case study tries to develop product-service value blueprint for the customer service department based on the assumption that market requirements have been efficiently identified.

Industrial applications

Aviation industry can show the highly interdependent relationship among stakeholders in value network. This civil aircraft manufacturer could be divided into three departments: design center, manufacturing center, and service center. Along with the lifecycle of civil aircraft, all stakeholders (customers, suppliers, partners and stockholders) participate in value creation around the core enterprise (aircraft manufacturer). Customer services of civil aircraft lifecycle need closely collaboration among customers, suppliers, design department, and manufacturer.

In the value chain of traditional civil aircraft manufacturer, service business belongs to the downstream and is accessory of aircraft sales. As shown in figure 10, in order to develop into an international aviation service solution provider, this enterprise escapes the shackles of traditional value chain (value chain decomposition), construct service value chain and develop core service business (value chain expansion), and finally re-engineering value chain (value chain integration). The main customers of civil aircraft manufacturer are airlines, so it is important to streamline value chain after identifying customer value, optimize core business process under value chain management, and realize value-added through service innovation around business needs of airlines. The whole service system is established through the four steps of value creation process.

Industrial product-service is beneficial for manufacturing industry upgrading on value chain in order to get more profits. This paper study on product-service from the perspective of value creation and proposes a framework of product-service value creation. And it also provides a new research road of product-service. However, the study in this paper is mainly based on qualitative discussions. And it needs the quantitative model and algorithms which are the follow-up study of authors in the future.

Fig. 3 .Fig. 4 .

 34 Fig. 3. Product-service Value Creation Process

Fig. 7 .

 7 Fig. 7. Product-service Value Delivery Process

Fig

  Fig. 8. Product-service Performance Evaluation 4 Case study

Table 1 .

 1 Product-service Value Define

	Dimension	Value	Description
	Reliability	Safety Value	The validity and reliability of product-service
	Responsiveness	Efficiency Value	The speed, betimes, and activeness of product-
			service
	Assurance	Credible Value	The power of delivering promised product-
			service
	Empathy	Flexible Value	Personalization	of	service	process;
			participation and feedback of customers
	Tangible	Social Value	Service encounter; service behavior; and
			service display
	Economical	Economic Value	Value perception and service contract

Acknowledgments. The author would like to thank Shanghai Institute of Producer Service Development (SIPSD) and Shanghai Research Center for industrial Informatics (SRCI2) for the funding support to this research.

UPSTREAM Upstream

Potential industrial benefits

According to the value creation model, the sustained profitability of service enterprises derives from close cooperation among stakeholders of value network. Through the external value network analysis, service enterprises could extend their internal value chain from manufacturing domain to service domain and improve their position in the value chain. Based on the optimized value chain, service enterprises could integrate and cultivate service capability through service innovation.

With the value creation process, the product-service blueprint of civil aircraft could be formed which is divided into three parts: basic services, extended services, and value-added services. The basic services are supportability services used to meet the flight demands of safety and reliable. It must be provided to airlines by manufacturer and meet the minimum industry standard. The extended services are used to improve customer satisfaction and assist airlines to reduce operation and maintenance costs. The value-added services belong to innovative services. It is highly customized service solution and needs advanced service technologies and equipment. It could raise the service profit and would not be copied easily by competitors.


Marwa Bouzid
email: marwa.bouzid@supmeca.fr

Mohamed Ayadi
email: ayadi1med@yahoo.com

Vincent Cheutet
email: vincent.cheutet@insa-lyon.fr

Mohamed Haddar
email: mohamed.haddar@enis.rnu.tn

Proposition of a conceptual model for knowledge integration and management in Digital Factory

Keywords: Knowledge, capitalization, management, digital factory, information system

The key of successful industry is to satisfy the customer requirements at the perfect delay with improved quality and cheaper price. In this context, Digital Factory is known to test and validate the couple product-production system during the Product Development Process (PDP), with the usage of production system simulations; therefore we can use an information system like InfoSim to integrate and manage all information related to product, process and simulation in this context. But with this huge amount of information, an actor of PDP may be confused to make a good decision at this particular stage. Thus, there is a lack of knowledge capitalization and sharing between PDP actors. In this research work, we propose a conceptual model dedicated to the management and capitalization of knowledge and experiences of previous projects in the context of Digital Factory.

Introduction

In recent decades, a large number of companies sought to value the intangible investment (research and development, training, advertising, organizational methods, etc.) and, in particular, their capital knowledge. This capital is then re-used in different situations in order to reduce the costs and the times of development [START_REF] Admane | A generic model of corporate memory: application to the industrial systems[END_REF]. Among such knowledge-based situations, digital prototyping (based on the concepts of digital models representing the product, its physical behavior, and its manufacturing process) is a solution to test and validate a product earlier in its lifecycle [START_REF] Hoppmann | The Lean Innovation Roadmap-A Systematic Approach to Introducing Lean in Product Development Processes and Establishing a Learning Organization[END_REF]. In particular, Digital Factory (DF) was born to design and simulate production systems throughout the product design process. It can be defined as a set of software tools and methodologies allowing the design, simulation, initiation and optimization of production systems [START_REF] Bracht | The Digital Factory between vision and reality[END_REF][START_REF] Chryssolouris | Digital manufacturing: history,perspectives, and outlook[END_REF][START_REF] Kuehn | Digital Factory -Integration of simulation enhancing the product and production process towards operative control and optimisation[END_REF]. Despite the high performance of simulation tools in digital manufacturing [START_REF] Coze | Virtual concept real profit with digital manufacturing and simulation[END_REF], there is a lack of deployment related to [START_REF] Ayadi | Conceptual Model for Management of Digital Factory Simulation Information[END_REF][START_REF] Nagalingam | CIM-still the solution for manufacturing industry[END_REF] the intrinsic complexity of DF but above all, the absence of integration of information and knowledge from previous projects of production systems simulation,

The management of information and knowledge between the product and its production process, including data related to resources, is so essential. Indeed, the solution adopted for product development is to integrate different types of information and knowledge (product, process and resources) as soon as possible to make the right decisions at the right time [START_REF] Ayadi | Conceptual Model for Management of Digital Factory Simulation Information[END_REF].

Most researchers have focused on the product knowledge whereas some others have interested on the process planning. Thus we identify the following research gap: how to manage and control all knowledge types in the context of DF, including product, process, resource and DF simulation one.

Based on previous research works that contribute to InfoSim, a framework dedicated to DF data and information management and control [START_REF] Ayadi | Conceptual Model for Management of Digital Factory Simulation Information[END_REF], the main objective of our current research work is to model and implement inside InfoSim a framework for the management and the control of knowledge for digital design and production, allowing to manage and improve the possible DF simulations, and also focusing on knowledge capitalization and experience feedback towards new DF projects.

The article is structured as follows. Section 2 presents a study of the literature: first, we define knowledge management then we analyze existing methods of knowledge capitalization. Section 3 describes the conceptual model of the proposed framework which it will be validated with case study in section 4. Finally, Section 5 presents the conclusions and perspectives.

State of the art

Knowledge Management

In 1991, Tom Stewart advised the company to focus more on their knowledge than on their material goods: « Intellectual capital is becoming corporate America's most valuable asset and can be its sharpest competitive weapon. The challenge is to find what you have -and use it» [START_REF] Grundstein | De la capitalisation des connaissances au management des connaissances dans l'entreprise, les fondamentaux du knowledge management[END_REF].

Baizet defines the knowledge like refined, synthesized, systematized information, or like information associated with a context of use [START_REF] Baizet | Knowledge Management in design: Application to the computational mechanics at Renault-BED[END_REF]. With this definition it is clear that there is a difference between the words: data, information and knowledge, while Tsuchiya differentiates these terms with this definition: « Although terms "datum", "information", and "knowledge" are often used interchangeably, there exists a clear distinction among them. When datum is sense-given through interpretative framework, it becomes information, and when information is sense-read through interpretative framework, it becomes knowledge » [START_REF] Grundstein | De la capitalisation des connaissances au management des connaissances dans l'entreprise, les fondamentaux du knowledge management[END_REF].

Most of the authors, like Grundstein, Nonaka and Takeuchi, divide knowledge into two kinds: explicit knowledge and tacit knowledge (know-how) [START_REF] Grundstein | Reinforcing decision aid by capitalizing on company's knowledge: Future prospect[END_REF][START_REF] Nonaka | The Knowledge-Creating Company[END_REF]. Explicit knowledge refers to knowledge transmitted through a "formal and systematic" language [START_REF] Lalouette | Gestion des connaissances et fiabilité organisationnelle : état de l'art et illustration dans l'aéronautique[END_REF]. It is a technical or academic data or information that is described in formal language, like manuals, mathematical expressions, copyright and patents [START_REF] Smith | The role of tacit and explicit knowledge in the workplace[END_REF].

Tacit knowledge refers to know-how that is difficult to formalize and communicate and can't be transferred that by the willingness of people to share their experiences, it is usually acquired over a long period of learning and experience [START_REF] Grundstein | Reinforcing decision aid by capitalizing on company's knowledge: Future prospect[END_REF][START_REF] Lalouette | Gestion des connaissances et fiabilité organisationnelle : état de l'art et illustration dans l'aéronautique[END_REF].

Ermine assumes "knowledge management is the goal of formalizing tacit knowledge in order to make mobilized and operational at the level of the entire organization" [START_REF] Ermine | Challenges and approches for Knowledge Management[END_REF]. Then Nonaka and Takeuchi represent the transformation mechanisms involved between explicit and tacit knowledge (as shown on fig. 1(a)) [START_REF] Nonaka | The Knowledge-Creating Company[END_REF]. Skyrme defines "Knowledge Management is the explicit and systematic management of vital knowledge and associated processes including the creation, collection, organization, dissemination, use and exploitation of knowledge. KM requires the passage of personal knowledge to collective knowledge that can be shared widely in organization " [START_REF] Skyrme | knowledge management: making sense of an oxymoron[END_REF]. With this definition Baumard represents the individual and collective knowledge transformation mechanisms (as shown on fig. 1. (b)), so he completed the model of Nonaka and Takeuchi [START_REF] Baumard | Tacit Knowledge in Organizations[END_REF].

Ramon defines "knowledge management is the process through which an enterprise uses its collective intelligence to accomplish its strategic objectives" [START_REF] Barquin | What is the knowledge management?[END_REF]. Like in [START_REF] Lalouette | Gestion des connaissances et fiabilité organisationnelle : état de l'art et illustration dans l'aéronautique[END_REF], we can summarize clearly the aim of the KM operation with: "Getting the right knowledge to the right people at the right time in the right size without being asked". And the expression ''knowledge management'' covers all the managerial actions aiming to answer the problem of capitalization of knowledge in general [START_REF] Grundstein | Reinforcing decision aid by capitalizing on company's knowledge: Future prospect[END_REF].

McMahon assumes that there are two approaches in KM: Codification which focus on the reification of knowledge so it focus only on explicit knowledge and personalization which focus on individuals as holders of knowledge and which it justifies to take into account the tacit and explicit knowledge [START_REF] Mcmahon | Knowledge management in engineering design: personalization and codification[END_REF].

Knowledge Management allows companies to train their memory by the integration, sharing and reuse of all knowledge (tacit and explicit) of PDP actors which are related to product, process, resource and simulation in an information system. It is the solution of several problems (such as the complexity of DF, the amount of simulation data and the variety of viewpoints) in Digital Factory. Then it allows companies to store the best simulation results for reuse in another project with all viewpoints.

In order to propose a conceptual model for the integration and reuse of knowledge in DF (tacit and explicit knowledge of product, process, resources and simulation), we present, in the following section, the definition of Corporate Memory and some methods of knowledge capitalization presented in the literature.

Corporate memory and knowledge capitalization methods

A corporate memory is an explicit, disembodied, persistent representation of the knowledge and information in an organization" [START_REF] Heijst | Corporate Memories as a Tool for Knowledge Management[END_REF]. It includes not only a "technical memory" obtained by capitalization of its employees' know-how but also an "organizational memory" (or "managerial memory") related to the past and present organizational structures of the enterprise (human resources, management, etc.) and "project memories" for capitalizing lessons and experience from given projects [START_REF] Dieng | Methods and tools for corporate knowledge management[END_REF].

There are several methods of knowledge capitalization: some of these methods have been designed to define a project memory, others are more general.

We focus in this report on classical methods combining the technical, human and organizational aspects which can be presented according to two approaches:

• Corporate memory itself like methods REX (method of experience feedback), MEREX (Methodology and experience feedback) and CYGMA (Lifecycle and management of Jobs and Applications), that consider six categories of industrial knowledge with jobs' reference. Workshop FX results from work of social sciences which aim at using the actor's experience of the industrial process to create enterprise knowledge; • Models resulting from the knowledge engineering like KADS(Knowledge Acquisition and Design Structuring), CommonKADS(Common Knowledge Acquisition and Design Support), KOD(Knowledge Oriented Design) and MKSM(Method for Knowledge Systems Management) associated with its extension MASK(Method of knowledge analysis and structuration), Componential framework etc., which present various conceptual models interacting to each other [START_REF] Chebel-Morello | Knowledge capitalization in system of equipment diagnosis and repair help[END_REF]. These methods are generic and cannot cover our needs. In the next section we present our conceptual model dedicated to the integration and reuse of corporate knowledge. To do this, we chose UML as a tool for presentation of corporate knowledge.

Conceptual Model

Our proposed model is attached to the conceptual model of InfoSim (Fig. 2), which is an information system dedicated to manage information on simulations in digital factory, its objective is the integration of product's information, production processes and simulation [START_REF] Ayadi | Conceptual Model for Management of Digital Factory Simulation Information[END_REF].

In Fig. 2, DF entity that covers the main classes of the model Product Component, Process Component, Resource and Simulation. This class can also be associated to a file, version and to an experience that can be shared for future projects. One or more versions of Product, Process, Resource and Simulation can be considered in a DF Project which is associated to a control Graph [START_REF] Ayadi | InfoSim: Prototyping an Information System for Digital Factory management[END_REF].

Fig. 2. Conceptual Model of InfoSim [23]

The conceptual model of knowledge is depicted in Fig. 3. In this model the knowledge entity class can be used in Digital Factory project of InfoSim. This class includes the two main classes of the model: General Knowledge entity Project and Knowledge entity which is created in Digital factory project of InfoSim. In the attribute of these classes we can also specify the type of knowledge like tacit or explicit.

Every knowledge element contains its own content (Knowledge content class which gives a more detailed description of what is contained in the element) and is embedded in a specific context (Knowledge context class which depicts the comprehensive environment of the knowledge element for a better understanding.

We define a Knowledge context class with the all of attributes of the classes (View point of designer, manufacturer or simulator and knowledge creator), like a date, place and support.

In our modelling the knowledge content class is linked with the knowledge entity class through the composition relation, because if we remove the knowledge all its contents will be delated.

The knowledge content (which contains the attributes like the name, the file, the usage etc.) is attached to digital factory of InfoSim. It can be the knowledge of product, process, resource, simulation, materials or project knowledge which they are linked. Indeed a product is linked to a material and a Process. This last class require resource which can be human or machine, and human resource can also has a view point.

Case study

Our case study concerned the manufacturing of floating roof tank. The purpose of this case is to validate our conceptual model for integration knowledge in Digital factory. It has two general parts: the creation and the usage of knowledge.

Design process

The design phase is the activity of developing the best solutions from a given need. The first phase contains several steps. In each steps we can used general knowledge and results of previous projects and we can obtained project knowledge. Indeed every company has a general knowledge that it can be used in several projects and helps actors to make the right decision in the right time. Moreover each project can be used in others projects.

Materials

Standards and normes

Previous project results

Fig. 4. Digital manufacturing process of tank in digital factory

Fig. 4 shows the knowledge that we need to know during the design phase like data sheet materials, the standards API650, software Tutorials, drawings of standard pieces, designer knowledge, view point of manufacturer and simulator and the results of previous projects. Each of this knowledge has a content that is product knowledge and has a context which can be the viewpoint of PDP actor and the creator. Moreover, all results of this project will be a project knowledge that we will use in the future.

Digital manufacturing process

A range of manufacturing is a document that lists all phases of part development. It is noted step by step the evolution of part manufacturing. According to studies conducted by the company, we can divide the manufacturing phase into two main groups:

• Part transformation process

• Assembly process Fig. 4 shows the knowledge needed to know manufacturing duration phase like all company resources (ability skill and experience of human, features and technical data of equipment), workers knowledge in video format, manufacturer knowledge, a point of view of the simulator and designer, manufacturing range of previous projects. Therefore, we used the corporate knowledge (General and Project) which are related to resource and process (content) then we obtained project knowledge. This knowledge has also a context like the creator and viewpoint of simulator and designer.

Simulation process in Digital Factory

The simulation is used to study the physical flows (parts, materials, tools, etc.), informational in the workshop (Manufacturing orders, assembly order, etc.) and the availability of resources (operators, machine, conveyors, etc.). It is used to evaluate and compare several scenarios. Fig. 4 shows the knowledge that we need to know during the simulation phase like the knowledge simulator, view point of designer and manufacturer, previous project results, tutorials of simulation software etc. During this phase we obtain the simulation results for the best solution in the project knowledge and we can also put the other results simulation in the general knowledge. These results can help actors to make the right decisions in other projects.

Conclusions et Perspectives

In this study, starting from the concept of knowledge Management, we propose a conceptual model that supports Knowledge integration in digital factory. Our model allows the creation, the sharing and the reuse of knowledge earliest during the PDP. It allows also the integration of all explicit and tacit knowledge of PDP actors and workers. In our model, we proposed that every company has two types of knowledge: project knowledge and general knowledge. Each of this knowledge has a context and content. Else we linked our model with the InfoSim model. Indeed during the creation a new project we need to know all company knowledge (project and general knowledge) to make the right decision at the right time. Furthermore project knowledge is created by the digital factory project. Then, an industrial case study has been presented for illustrating the applicability and validity of the proposed model. We described in our case all the knowledge that we need during the phase of design, manufacturing and simulation and all knowledge which it can be obtained during a project development.

Various prospects for future work have been proposed for this conceptual model. The aim of this work will be to enable the model to support the integration and reuse all knowledge in digital factory. Thus we will implement and test our model in the information system InfoSim.

Fig. 1 .

 1 Fig. 1. The transformation mechanisms between (a) tacit and explicit knowledge [12] (b)individual knowledge and collective[START_REF] Baumard | Tacit Knowledge in Organizations[END_REF]

Fig. 3 .

 3 Fig. 3. Conceptual Model

Table 1 .

 1 Project knowledge.

			Creator	Designer	Manufacturer	Simulator
				Viewpoint	Viewpoint	Viewpoint
		Material	×	×	×	×
		Study and	×	×	×
		calculation
	Product	Part list	×	×	×	×
		Part Simulation	×	×	×
		Product list	×	×	×
		Product simulation	×	×	×
	Process	Part transformation process	×	×	×	×
		Assembly Process	×	×	×	×
	Resource	Worker list Machine list	× ×		× ×	× ×
	Simulation Results simulation	×	×	×	×

Table 2 .

 2 General knowledge.

	Kn Content	Kn Context
		Kn Context
	Kn Content		Creator	Designer Viewpoint	Manufacturer Viewpoint	Simulator Viewpoint
		Material	×	×	×	×
	Product	Standards	×	×	×	×
		Standards Parts	×	×	×	×

(a) (b)


Morteza Poorkiany
email: morteza.poorkiany@ju.se2joel.johansson@ju.se3fredrik.elgh@ju.se

Joel Johansson

Fredrik Elgh

Design and FEA

Keywords: Capturing, Structuring, and Accessing Design Rationale Across Product Design automation system, computer supported engineering design, design rationale

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

For many companies it is important to innovate and launch new products according to new customer demands. Because of intense competition in the market and the need to being faster in developing new products, the firms attempt to control the quality of the product and manage the product information. PLM as a backbone to manage productrelated knowledge, and technology used to access to this knowledge, through different domains of product lifecycle, helps the organizations to overcome the engineering challenges and complexities during developing new products. A PLM system is a discipline emerged from different methods and tools across different phases of product and can work as a hub for product development systems in order to increase reliability and facilitate exchange of product information [START_REF] Bergsjö | Product Lifecycle Management-Architectural and Organisational Perspectives[END_REF]. Design process is an important element in PLM because making proper decisions at this early stage could optimize the development process and support the organizations to deliver their business initiatives and strategic goals. Design work encompasses a wide range of methodological approaches in order to solve different technical problems that require different solution strategies [START_REF] Sunnersjo | A transparent design system for iterative product development[END_REF]. Regarding the time-intensive nature of many design tasks, up to 80% of design time is spent on routine tasks [START_REF] Stokes | Managing engineering knowledge: MOKA: methodology for knowledge based engineering applications[END_REF] such as modifying, adapting or redesigning already existing and proven solutions. Such activities that do not rely on high creativity can be performed automatically with the help of skillful automation tools executing existing design knowledge. Design automation systems may have long life-span and require maintenance for proper function. Since the systems mainly manipulate and process design information, to maintain a system over time, frequent updating of design information is a necessity. Consequently, there is a need of principles and methods to support management of associated knowledge, specially, design rationale. Design rationale mainly explains the reasons behind the design decisions and developed solutions and helps to understand the effects of decisions on other aspects of design. This study aims to investigate how design rationale can be introduced to support the use and maintenance of design automation systems. A focus is set on the need to share knowledge between FEA and product design when introducing design automation which automates the process of developing FEA models of customized designs. In order to manage the required design rationales, a method addressing capturing, structuring, and accessing to design rationale has been presented. The applicability of the method has been tested in a company acting as a supplier in the automotive industry providing unique product solutions for different car models.

Frame of reference

The importance of access to design rationale was studied in a survey [START_REF] Tang | A survey of architecture design rationale[END_REF]. Approximately 80% of the respondents said they fail to understand the reason of a design decision without design rationale support. Lee [START_REF] Lee | Design rationale systems: understanding the issues[END_REF] defines design rationale as,"… not only the reasons behind a design decision but also the justification for it, the other alternatives considered, the tradeoffs evaluated and the argumentation that led to the decision". The realization of a design rationale system encompasses methods and tools to capture, structure, and share design rationale across organizations, processes, systems and products. The challenges regarding capturing, structuring, and accessing to the design rationale are discussed in [START_REF] Dutoit | Rationale management in software engineering: Concepts and techniques[END_REF]. One of the problems for design rationale capture is to define how and what type of knowledge should be captured. Indeed, any type of design information (e.g. product specification, geometries, design tables, rules, and catalogues) can potentially be a part of a design rationale. Capturing design rationale, especially when predefined templates and schemas are needed to be filled in, could intrude the design process and disturb the designer. Embedding the capture process in the current practice of the engineers would be a solution to overcome such problem. In addition, structuring and representing the design rationale because of the variety in type and format could be a challenge for the system developers. Well-structured design rationale makes it easy for the users to maintain and update the contents of the system. Moreover, the design information is stored in different software applications, therefore, the interaction between the design rationale system and the software applications at the company should also be considered by the system developers.

Related work

In a recent research [START_REF] Johansson | Design Rationale Management-a Proposed Cloud Solution[END_REF][START_REF] Poorkiany | Supporting Tooling Design Of Customized Products By Instant Access To Design Rationale[END_REF] that was performed by the authors, a method for design rationale capture, structure, and access was introduced. The idea was to provide an integrated design environment constituted of traditional software applications commonly used by the designers. A computer-supported engineering system could be developed for administration and management of information flow between the software. The method enables the engineers to concurrently capture, structure, and access to the design rationale in different software. The discussed method identifies design rationale with three elements described as follows:

• Design rationale targets are references targeting underlying design information.

Targeting a feature in a CAD model, specific bookmarks in a word processor documents, selections in plain text documents, and a range of cells in spreadsheets.

• Design rationale description is an explicit description (preferably in web page format) explaining different design issues. The aim is to record the part of the design rationale that is not captured in other software. • Design rationale connection is a set of design rationale targets that includes any of the software applications.

A prototype system embedding SolidWorks, Word, Excel, and wiki pages was developed for evaluation of the method (see figure 1). The aim was to choose different wide spread software to represent the design rationale in different formats.

The system was coded in VB.net environment and could be installed as extension in Word, Excel, SolidWorks, and a web browser. It is also possible to target more software applications if beneficial. So, the design rationale for an artifact in the prototype system consists of a set of targets such as a feature in SolidWorks, a table in Excel, a number of lines in Word, and a description such as a web-page in wiki. These all are connected together via the "connection" functionality provided in the system (see figure 1 left side). The system provides similar user interfaces containing three windows for displaying the targets, connections, and descriptions in all four applications (see figure 1 right side). This makes it possible to select a target (e.g. a feature in SolidWorks) and see the related targets (e.g. a design table in Excel), or descriptions (wiki pages) concurrently in all the applications via the user interface.

Management of design rationale in product design and FEA

Taking into account the purpose and intended use of design rationale is necessary when developing a design rationale method. It should be clarified what knowledge needs to be captured and how structure it in order to share the right details of the knowledge for the users. Further improvements to the previously discussed design rationale method are provided in this section. Performance of the assembly iii.

Interaction of a component with other components b) FEM analysis information. Necessary information for finite element analysis of the whole assembly.

2. How design rationale should be captured? 1) Identify design rationale targets

2) Attach a description to the target if required 3) Connect the target to the related targets in either the current or other software.

The design rationale can be captured by the engineers through design and FEA phases. So, the designer is responsible for capturing the reasons behind the design decisions, while, the FEM engineer captures the analysis information for the design. Retrieval of the captured design rationale is easier when the design rationale is structured and classified within different categories. Since design rationale has been identified as a set of design rationale targets and a set of design rationale descriptions, one way to structure the content would be classifying the targets and descriptions (i.e. the wiki). The suggestion is to categorize all the targets into a connection if there is any relationship between them (see figure 1). In addition, similar to Microsoft Windows or GUI operating systems, folders as virtual locations can be created to help users store and organize the connections. The wiki pages on the other hand, can be classified in different categories. Finally, all the design rationales shall be accessible and monitored in a standardized way. Accessibility can be supported by providing search techniques enabling the user to search the information according to the needs.

Case study

A system for automatically develop a complete FEA-model by integrating a CAD system and FEA pre-processor was introduced by one of the authors in [START_REF] Johansson | A Feature and Script Based Integration of CAD and FEA to Support Design of Variant Rich Products[END_REF]. The prototype system connected Solidworks, ANSA, and LS-Dyna to automate the crash simulation process by providing structured mesh. An extension was developed and installed in SolidWorks to scan the CAD-model to generate a macro for different features, execute the macro to render the mesh model, appended the mesh model and compile the final model to the format of the targeted FEM-solver. Figure 2 displays generating mesh models in CAD software and FEM pre-processor. When running the system, FEA-models are generated in less than 4 minutes compared to up to a week when done manually. This increases the amount of tested product proposals ultimately increasing the product quality without increasing the product cost. Figure 3 shows a screenshot of a component (Footpad) in SolidWorks with both the design automation system on top, and the design rationale system on right. In this picture two windows of the design rationale system are shown: design rationale targets are displayed on the top and design rationale connections in the lower window. Footpads are part of the solution which are developed in the case company for attaching a roof rack on different car models. Generally, a new Footpad has to be designed for every new car model. Since the Footpad is directly adjusted on the car's roof, analyzing the safety of the Footpad is strongly advised to the engineers and a crash simulation should always be performed on the roof racks.

To create the FEA model and run a crash simulation for the Footpad, a number of features in the design automation system such as defining material properties, thermal expansion, and surface contact need to be determined by the FEM engineer.

Fig. 2 .

Generating mesh-models in the design automation system.

The features are accommodated in SolidWorks (e.g. Material feature in the left panel in SolidWorks in figure 3). Simulating a new Footpad variant with new properties requires updating these features and creating a new FEA model. In addition, some decisions made in the design phase might also effect the FEA model and the crash test. For instance, the crash analysis might be valid for a range of Footpad alternatives which a designer could consider it during designing a new variant. Thus, capturing and sharing the design rationale behind both the FEA model and geometry would support the FEM engineers to update the FEA model and run the crash simulation faster and more efficient.

Design rationale capture

This section shows how the required design rationale for updating a FEA model can be captured. Two design rationale targets are displayed in figure 3. One targets the material property (Rubber) which is determined by the FEM engineer. The other one targets the height of the highlighted curve in the CAD model. The shape of the curve which is an important factor in finite element analysis varies in different Footpad variants and depends on the roof's geometry. The Connection window in figure 3 displays two documents connected to the targets. The documents are Excel and Word shown in figure 4. Excel document on the left side contains information about design alternatives for the Footpad. Word document on the right side contains information about material properties of the Footpad variants. The highlighted cells in Excel are connected to "Footpad Height Alternatives" target and the highlighted text in Word is connected to "Footpad Simulation" target. So, the designer captures information explaining the whys and design alternatives for the Footpad via the user interface (stated "Footpad Height Alternatives" in Excel in figure 4). The FEM engineer captures information explaining material specification for the Footpad (stated "Footpad Simulation" in Word in figure 4). In addition, two wiki pages; one describing the Footpad, its design process of the Footpad and supported documents, and the other one explaining the simulation workflow and tasks are presented in the bottom of Excel and Word. Figure 6 shows the wiki page with the same user interface as the other software, containing the simulation information (this wiki was presented in Word in figure 4). Additionally, the prototype system allows classifying the design rationale into folders. Each folder can be used for a specific context. For example, the design rationale targets in figure 4 are stored in three folders named: Bracket Information (contains targets for the Bracket component), Footpad Information (contains targets for the Footpad component), and Roof Information (contains targets for the cars' roofs). The system allows the engineers to create folders and classify the design rationale based on their context in the respective folder.

Design rationale access

One way to support retrieval of existing design rationale is to allow search based on project, domain, date, name, etc. which is a simple task for system developers to provide such functionality. For instance, a user can search among the design rationales looking for a specific notation or vocabulary included in their contents. In order to expose information retrieval, in this study a search function is provided based on the names of the design rationale targets. Figure 7 shows an editor that is developed for the prototype system. The editor could have a number of functionalities which the most important ones are edit, manage, and search for the information. It is possible to monitor all the design rationale targets by selecting "Show all" in the "select" combo box (see figure 7 left side), or search for specific notation in the targets' namespaces by selecting " start with" or "contains". Figure 7 right side shows the result of a search for keyword "footpad" in the combo box. For each monitored design rationale target in the list view, the attached wikis (description) and connections are displayed in the property grid (see figure 7 right side).

Conclusion

This study examined the importance of retrieving design rationale to support the use and maintenance of design automation systems. A method addressing capturing, structuring, and accessing to design rationale was presented. An example for capturing the design rationale in component level was provided. However, more studies are required regarding details of the information to be captured in both component level and assembly level while avoiding knowledge duplications. Retrieval of the design rationale based on the targets' namespaces was investigated to show the high potential of search engines in finding the design rationales, more specifically, when particular keywords are predefined.

A prototype system for managing design rationale by embedding the common design software was evaluated in this study. A major benefit of such integration is to allow the organizations to model the design rationale system according to their needs and strategic goals. However, traditional issues regarding aligning the system with design environment, platforms, and IT-infrastructure always occur during implementing the system which is one reason for failing the systems in practice. Currently, both the design rationale and the design automation systems are in prototype phase so it is not possible to quantify the benefits of the proposed method at this time. There is a need to investigate implementing and integrating the system across complex platforms on a larger scale in the company.

Fig. 1 .

 1 Fig. 1. The generic architecure of the design rationale method.Generally, a customized product is constituted of assemblies that each assembly includes a number of components or maybe another sub-assemblies. Depending on the current task of the designer (designing a component or assembling a number of components together), the design rationale can be captured in different details to avoid recording duplicated knowledge. Below is a framework developed for capturing design rationale addressing what should be captured as design rationale and how. The framework targets two important phases of the development process: design phase and finite element analysis which making a decision in one highly effects the other one. FEA is mainly the analysis of the design and shows whether the part or assembly work the way they are designed which can steer the designers toward a more costeffective product.1. What details of design rationale should be captured?1.1 Design rationale capture in component design.a) The captured design rationale shall explain why the component is designed as the way it is. It should also address: i. Performance of the component. b) FEM analysis information. Necessary information for finite element analysis of the component.1.2 Design rationale capture in assembly design. a) The captured design rationale shall explain why the assembly is designed as the way it is. It should also address: i. Performance of the component in the assembly ii.Performance of the assembly iii.Interaction of a component with other components b) FEM analysis information. Necessary information for finite element analysis of the whole assembly.

Fig. 3 .

 3 Fig. 3. Design automation and design rationale systems embedded in Solidworks.

Fig. 4 .Figure 5

 45 Fig. 4. Design rationale targets, descriptions, and connections in Excel and Word.

Fig 5 .

 5 Fig 5. Structuring knowledge in wiki pages.

Fig. 6 .

 6 Fig. 6. The wiki page containing information regarding simulation process and the provided user interface.

Fig. 7 .

 7 Fig. 7. Search function in the prototype system.

Acknowledgement

This study is a part of the Impact project financially supported by Knowledge Foundation (KK-stifitelsen) in Sweden. The authors are grateful to Thule Group for providing the technical facilities for the research.