Improvement of product design process by knowledge value analysis

Transcription

1 Improvement of product desgn process by knowledge value analyss Yang Xu, Alan Bernard, Ncolas Perry, Florent Laroche To cte ths verson: Yang Xu, Alan Bernard, Ncolas Perry, Florent Laroche. Improvement of product desgn process by knowledge value analyss. CIRP Desgn Sustanable Product Development, Sprnger, pp , 2013, < / _20>. <hal > HAL Id: hal Submtted on 4 Feb 2014 HAL s a mult-dscplnary open access archve for the depost and dssemnaton of scentfc research documents, whether they are publshed or not. The documents may come from teachng and research nsttutons n France or abroad, or from publc or prvate research centers. L archve ouverte plurdscplnare HAL, est destnée au dépôt et à la dffuson de documents scentfques de nveau recherche, publés ou non, émanant des établssements d ensegnement et de recherche franças ou étrangers, des laboratores publcs ou prvés.

2 Scence Arts & Méters (SAM) s an open access repostory that collects the work of Arts et Méters ParsTech researchers and makes t freely avalable over the web where possble. Ths s an author-deposted verson publshed n: Handle ID:. To cte ths verson : Yang XU, Alan BERNARD, Ncolas PERRY, Florent LAROCHE - Improvement of product desgn process by knowledge value analyss Any correspondence concernng ths servce should be sent to the repostory Admnstrator : archveouverte@ensam.eu

3 Improvement of product desgn process by knowledge value analyss Yang XU a, Alan BERNARD b, Ncolas PERRY c, Florent LAROCHE b CIRP Desgn Sustanable Product Development , pp a Pekng Unversty - Department of Informaton Management, Ch Bejng yang.xu@pku.edu.cn b IRCCyN UMR CNRS Ecole Centrale de Nantes, F4400 Nantes alan.bernard@rccyn.ec-nantes.fr c Arts et Méters ParsTech - I2M UMR 5295, F33400 Talence n.perry@2m.u-bordeaux1.fr Abstract Nowadays, desgn actvtes reman the core ssue for global product development. As knowledge s more and more ntegrated, effectve analyss of knowledge value becomes very useful for the mprovement of product desgn processes. Ths paper ams at proposng a framework of knowledge value analyss n the context of product desgn process. By theoretcal analyss and case study, the paper llustrates how knowledge value can be calculated and how the results can help the mprovement of product desgn process, such as decdng whch knowledge to choose and what to do next. 1.1 Introducton In ths world of globalzaton, more and more enterprses consder knowledge management (KM) process as an mportant part, f not the only part, of ther producton actvtes (Nonaka and Takeuch, 1995; Bernard and Tchkewtch, 2008). Meanwhle, how to pay deeper attenton to the crucal competence knowledge s becomng a strategc approach n producton management, and product desgn process s lnked more and more tghtly wth knowledge (Perry et al., 2011). When consderng knowledge management n product desgn actvtes, how to evaluate knowledge has always been a challengng problem. Whch knowledge s more useful and thus can add more value to the product? What knowledge to be acqured n the next step of desgn? The answers of such questons may greatly mprove desgn actvtes, so the followng sectons wll focuses on ths related ssue: how to calculate and analyze knowledge value n product desgn processes and help them mprove.

4 2 Author s Intal(s) Author s Last Name ( Runnng head left style) 1.2 How to evaluate knowledge value Product development process We may descrbe the product development process as the followng procedure: a product starts from ts ntal state and arrve to a requred state (fnal state), and a task T s supposed to be accomplshed to realze ths product evoluton from that ntal state P 0 to the fnal state P n. The product development process can be descrbed by a seres of state changes. Gven an ntal state P 0, the product development process can be characterzed by a sequence of product states «P0 P1 P2 L Pn», where P 1 s the product state when t 1 s accomplshed, P 2 s the product state when t 2 s accomplshed, etc., and when task T s accomplshed, the product comes to ts fnal state P n. Task T can be defned as follow. Defnton 1. Task T s represented by a weghted drected graph, where: G ( T ) = ( H, A, Ω) H s a set of tasks, whose elements are the task T, the non-atom tasks t m and the atom-tasks at,.e., H = h } = { T, t, t,..., t, at, at,..., at } ; n A s a set of drected arcs α pq,.e. h p and q h p to h q ; Ω s a set of weghts pq { 1 2 m 1 2 n h are lnked by α pq, from whch are assgned to each arcα pq. Partcularly, the sub-tasks whch do not have successors are named atom-tasks, noted as at. The reason that T s characterzed by a graph, not a tree, s that there may be several sub-tasks whch are not ndependent and they may have one or several sub-tasks n common.

5 Chapter Number Chapter Ttle ( Runnng head rght style) Knowledge value Supposng that knowledge K s necessary to accomplsh the task T and knowledge fragment k s needed to accomplsh sub-task t, thus, k s the soluton for the sub-task t, and knowledge K can be consdered as a set of solutons whch together can accomplsh the task T. Obvously, a knowledge fragment can be a person, a book, a plan or any type of solutons provded, and knowledge characterzaton n detal can be referred from the works of Xu and Bernard (2010a). Based on ths proposal, some questons may be rased. Is knowledge K can accomplsh the task T completely? If knowledge K can only solve a part of the task T, whch part s solved? What knowledge fragments k k have to be added n order to solve the remanng parts? How to choose the knowledge fragments k to accomplsh the unsolved sub-tasks? In order to answer these questons, some hypotheses are frstly presented: Hypothess 1. The atom-tasks are noted as at, and all atom-tasks correspond to an explct answer yes or no whch shows whether t can be solved or not. In other words, the atom-tasks cannot be solved partally. Hypothess 2. The prncples of task decomposton are as follows. If the taskt s decomposed nto T 1, T 2,..., T n, we have: a. T T T... T ) ( 1 2 n (The combnaton of the sub-tasks should cover the orgnal task T ) b. T T (Any sub-task T cannot cover the orgnal task T ) c. The task T s decomposed wth weghts, noted as: T n : T + T T n n, and = 1 = 1. (The weghts ndcate the mportance of the sub-tasks to the orgnal task, for example, f the desgn of a car focuses more on speed mprovement, then the sub-task of speed mprovement wll have a hgher weght than the sub-task of cost dmnuton)

6 4 Author s Intal(s) Author s Last Name ( Runnng head left style) The value of knowledge K to the task T s noted as V T, K ) (. Ths notaton ndcates that knowledge s always n context, n other words, knowledge evaluaton s lnked wth specfc tasks. Knowledge value thus vares accordng to dfferent tasks. For example, gven a same knowledge fragment to adjust the heght of a char, t could have a hgh value to the task to consder the ergonomcs and have a low value to the task to control the cost. The value of knowledge K to the atom-task at s defned as follows. Based on the two hypotheses and Defnton 2, knowledge value can be measured by the procedure as follow. Procedure for knowledge value measurement: Step 1: All the value of knowledge K to the atom-tasks s obtaned accordng to Defnton 2. Step 2: For any h H, fnd all the ( h, hj ) and ther assocate j, then: = V ( h, K) V ( h, K) j The procedure shows that from Step 1 we can obtan all the V ( at, K) and from Step 2 we can obtan ( T, K) j V. When V ( T, K) 1 j, t means there are one or several sub-tasks whch are not accomplshed, so addtonal knowledge s necessary to make V ( T, K) = 1. Durng ths process of knowledge addton, both explct knowledge and tact knowledge mght be needed. Usually, explct knowledge comes from databases, publcatons, rules, etc. and tact knowledge comes from experence, expertse, wsdom, judgment, etc. If Defnton 2. K can solve at and weghts of,,..., m, then m at s lnked to T by a sequence of arcs wth V ( T, K ) = u V ( at, K ) = at V ( at, K u= 1 Ths calculaton process s realzed by a calculator called CAL-KNOW, whch s used n case study ntroduced latter. If two knowledge fragment K and K are both avalable, V ( T, K ) and V T, K ) can be calculated and compared. Generally, knowledge that has a ( 1, ( at, K) = 0, V at can be solved by K at can not be solved by K )

7 Chapter Number Chapter Ttle ( Runnng head rght style) 5 hgher value s usually chosen. As collaboratve networks s regarded as a crtcal success factor to acheve product nnovaton (Perry et al., 2010), t s always useful to choose the most valuable knowledge to be exchanged and shared. 1.3 Knowledge evaluaton n product desgn process Durng product lfecycle desgn, whch can be defned as a sequence of tasks (Nacsa et al., 2005), both tact and explct knowledge may be requred to accomplsh the tasks at, so these two knds of knowledge can add value to the knowledge of desgn K and thus make knowledge evoluton (Bernard and Xu, 2009; Xu and Bernard, 2010b). Here are the man steps to take durng the procedure of knowledge evaluaton n supportng product desgn. 1. To decompose of the product development process nto smpler processes, n other words, to realze the decomposton of the task T nto atom-tasks at. 2. To evaluate the value of the exstng knowledge usng the evaluaton model ntroduced n the prevous secton. 3. If not all the atom-tasks are solved, fnd out whch at should be solved next. 4. To add approprate knowledge, explct and/or tact, to accomplsh at. 5. Do Step 3 and Step 4 repeatedly untl all atom-tasks are solved. In the product desgn process, knowledge mat add value to products and product may also make knowledge more valuable (Xu and Bernard, 2011), and such mutual value addng process can be explctly descrbe and controlled usng our knowledge evaluaton model. 1.3 Case Study Ths paper has chosen a case of char desgn, whch s a part extracted from the product lfecycle of a char. The concentraton s mplemented on the phase of desgn as t s a key phase where major decsons are made concernng knowledge. In ths example, the task «desgn a char» should be accomplshed n order to make the product (char) evolves n the development process. Fgure 1(1) and Fgure 1(2) llustrate how the task s decomposed. Although the decomposton s lack of completeness, for example, several tasks such as market study, packagng and

8 6 Author s Intal(s) Author s Last Name ( Runnng head left style) logstcs matters, partcular optmzaton, etc., are neglected, t can serve as an adequate demonstraton. Based on the crtera obtaned from experence n product desgn, the prncple task «desgn a char» s decomposed nto four sub-tasks. The weghts are gven by the experts of dfferent roles who have dfferent ponts of vew n desgn actvtes. Table 1 shows the weghts gven to each subtask by experts of dfferent roles. In order to determne a weght, we have taken nto account the results gven by a group of experts for each gven role. How to mprove the results of collectng and analyzng the weght values gven by dfferent people s another complcated topc, whch needs further researches on statstcal technques, human behavors, etc., and n ths paper, we smply regard the weght value as s the average of the weghts proposed by all the experts assgned n each group. Table 1.1 The values of weghts Experts of dfferent roles A Comfort/aesthetcs B Dmenson/Mechancs C Costs D End of lfe Clent 50% 10 30% 10% Desgner 10% 50% 30% 10% Manufacturer 0 30% 50% 20% Seller 30% 10% 40% 20% Transporter 0 60% 30% 10% Recycler % 70% Here are some llustratons about Fgure 1.1: «Percepton test» and «To consder the psychologcal comfort ssues» can be solved by questonnare surveys. «Ergonomc studes» manly focus on examnng the degree of fatgue of dfferent parts of the body (muscle, bone, jont, etc.) of a person who sts n the char for a perod of tme or by smulatons. «Tests of the materal attrbutes» may nclude the thermal conductvty (n wnter, people do not lke to st n a char wth a surface of ron, because t s too cold), the sensaton of the materal (for example, smooth or rough, soft or hard), etc. «To consder the aesthetcs of the char» consders the ntrnsc beauty of the char, whch depends on the cultural and socal context. In other words, for a same char, t may vary from beautful to dsgustng due to dfferent tastes of people from dfferent countres or groups.

9 Chapter Number Chapter Ttle ( Runnng head rght style) 7 To defne a skeleton To consder the geometry ssues To consder the materal attrbutes 100% B2111 B 2112 Choce of archtecture To obtan solutons from a branstormng To classfy the solutons whch can be selected 100% Archtectural desgn To consder the gravty support ssues B211 B212 To consder the mechancal support B21 To consder the postons of gravty B221 Detaled desgn To consder the stablty To consder the calculaton of swngng B22 B222 B1 B Task B To consder the dmensonal and mechancal desgn ssues Task C To consder the cost ssues C Desgn a char B A D Task A To consder the comfort and the aesthetcs ssues Task D To consder the product end-of-lfe ssues A1 A2 A111 A11 To consder the physcal comfort ssues Percepton test To consder the comfort ssues A112 A12 Qualtatve test To consder the psychologcal comfort ssues A21 A1121 A1122 Ergonomc studes Tests of the materals attrbutes To consder the aesthetcal ssues To consder the aesthetcs of the char A22 To consder the adaptveness n the context Fg. 1.1(1) The decomposton of the task «desgn a char» (Part I)

10 8 Author s Intal(s) Author s Last Name ( Runnng head left style) To consder Materal 1 To consder Materal 2 To consder Materal 3 D1 D2 D3 To consder the recyclng ssues D11 To consder the dsassembly ssues D12 To consder the nterface ssues D13 Task A To consder the comfort and the aesthetcs ssues Task D To consder the product end-of-lfe ssues A D Desgn a char C B Task C To consder the cost ssues Task B To consder the dmensonal and mechancal desgn ssues C1 C 2 To calculate the costs of materals To calculate the costs of labor C 21 To know the number of workers n the realzaton actvtes C 22 To estmate the workng tme of each worker C 23 C 24 To determne the salary of each worker To evaluate the costs for collaboraton C11 C Calculaton wthout consderng optmzaton 100% Calculaton consderng optmzaton C121 C122 Sngle-crteron optmzaton The types of materals The proporton of each materal The prce of each materal 100% Mult-crtera optmzaton The types of materals The proporton of each materal The prce of each materal The relatonshp among these parameters Fg. 1.1(2) The decomposton of the task «desgn a char» (Part II)

11 Chapter Number Chapter Ttle ( Runnng head rght style) 9 «To consder the adaptveness n the context of use» consders whether the char matches the envronment of use. For example, n a fast-food restaurant, sofas are not sutable to the envronment although they are very beautful. «Archtectural desgn» s consdered before the desgn n detals. For the assgnments of the values of the weghts B1 and B2, they depend on whether the desgner take optmzaton nto account. Table 2 shows two examples n determnng B1 and B2. In an extreme stuaton, when a desgner assgns B1 =100%, t means the desgner wll smply look for a soluton n a database of archved desgns. Table 1.2 The values of the weghts B1 and B2 If the desgner pay much attenton n optmzaton ssues durng the desgn process If the desgner do not wsh to spend too much tme n searchng for optmzaton solutons for Task B B1 B2 30% 70% 50% 50% The tasks «To consder the mechancal holdng ssues» and «To consder the stablty» have a same sub-task «To consder the postons of gravty centers». Such stuaton that several tasks may have a same sub-task n common s acceptable accordng to Defnton 1 whch defned the Task T as a graph. Here are two weghts whch have the value «100%». They mean that the tasks lnked by an arrow of a weght of «100%» are «equal». In ths case, when people have accomplshed «to defne a skeleton», they have accomplshed the «archtectural desgn» at the same tme. In order to determne the values of the weghts C1 and C 2, the context of desgn should be consdered, n other words, they depend on the amount of producton of the chars provded by customers. Table 3 gves two examples. In the condton that the char s desgned to be produced n large quanttes, the cost of materals has a weght of greater mportance. When t s a case of custom desgn, the weght of materals s lower. The clent s wllng to pay the extra cost for dfferentaton even f the materals used are more expensve.

12 10 Author s Intal(s) Author s Last Name ( Runnng head left style) Table 1.3 The values of the weghts C1 and C 2 C1 C 2 If the char s desgned to be produced n large quanttes 80% 20% If the char need a custom desgn wth a small amount of producton expectaton 20% 80% If several tasks have the relatons of ncluson, an arrow wth a weght of "100%" s used. Desgn optmzatons are often made retrospectvely by takng nto account new knowledge (Chenouard, 2007) Why the arrow from the task Sngle-crteron optmzaton to the task Mult-crtera optmzaton has a weght of 100%? Obvously, when people can perform the task of Mult-crtera optmzaton, they are able to accomplsh the task of Sngle-crteron optmzaton. In other words, these two tasks have a contanment relatonshp. In case when two tasks have a contanment relatonshp, an arrow of a weght of 100% s used. Optmzatons of the desgn are often made retrospectvely, takng new knowledge nto account, (Del Prete et al., 2010). Management of product end-of-lfe and recyclng are crtcal ssues n envronment treatment for manufacturng enterprses so they should be consdered n product lfecycle desgn (Bufard et al., 2003; Ueda et al., 2005). The task «To consder the recyclng ssues» needs knowledge about the possbltes of recyclng the materals used. The number of materals to be consdered s not lmted to three, and t may dffer from case to case. In other words, ths number depends on how many prncpal types of materals are used to buld the char. The three weghts D11, D12 and D13 are determned by several factors of the char, for example, the proporton of each materal used, the cost of each materal used, etc. The task «To consder the dsassembly ssues» evaluate whether the desgned char can be dsassembled. The easy dsassembly of a product wll facltate the recyclng of materal used and the reuse of dfferent parts of the char. The task «To consder the nterface ssues» manly consders the reuse ssues of dfferent parts of the char. For example, f a char has a leg broken, nstead of throw away the char and replace t by a new one, people can smply substtute the broken leg. But n order to realze the substtuton of the

13 Chapter Number Chapter Ttle ( Runnng head rght style) 11 broken leg, the nterface between the leg and the body of the char should be well desgned. In such cases, the desgn of the nterface should be gven specal attentons. In real cases tested, each tme a soluton (knowledge fragment) wth a hgher value s chosen, and from the lst of unaccomplshed atom-tasks, we could fnd out easly whch tasks should be accomplshed next. Every tme that K reaches a state that can solve one more task, ts value ncreases. When knowledge reaches ts fnal state, ts value may not always be 100%, but t s not crtcal f people are already satsfed wth ts current value. In the gven example, f we do not have to accomplsh the task of To calculate the cost of labor, knowledge can reman n a state that ts value s not 100%. In such cases, people have to take some rsks when they are gong to the next stage of the product lfecycle. 1.4 Conclusons Knowledge evaluaton s a key ssue n knowledge management, and ths paper has presented a knowledge evaluaton model n product lfecycle desgn. The model ntegrates the process of knowledge evoluton and product development, and the mutual effects between knowledge and product are analyzed. Based on the theoretcal defntons and models, ths paper llustrates how knowledge value can be assessed by studyng a specfc case. In the applcatons of product lfecycle desgn, knowledge values calculated by the model can serve as mportant factors n a decson makng system that decdes whch knowledge to choose and what to do next. The model could serve as a framework to descrbe the knowledge related actvtes and could be a useful tool for managng knowledge n product lfecycle desgn and support. Interestng perspectves may nclude deeper analyss about the optmzaton ssues of weghts and dynamc product development processes. 1.5 References Bernard A, Tchkewtch S Methods and tools for effectve knowledge lfe-cyclemanagement. Sprnger, Berln. Bernard A, Xu Y An ntegrated knowledge reference system for product development. CIRP Annals - Manufacturng Technology 58(1): Bufard A, Sakara D, Gheorghe R, Krtss D, Xrouchaks P Multple crtera decson ad for selectng the best product end of lfe scenaro. Internatonal Journal of Computer Integrated Manufacturng 16(7-8):

14 12 Author s Intal(s) Author s Last Name ( Runnng head left style) Del Prete A, Mazzotta D, Anglan A Desgn optmzaton applcaton n accordance wth product and process requrements. Advances n Engneerng Software, 41(3): Nacsa J, Bueno R, Alzaga A, Kovács GL Knowledge management support for machne tool desgners usng expert enablers. Internatonal Journal of Computer Integrated Manufacturng 18(7): Nonaka I, Takeuch H The knowledge creatng company. Oxford Unversty Press, New York. Perry N, Bernard A, Bosch-Mauchand M, LeDugou J, XU Y Eco Global Evaluaton: Cross Benefts of Economc and Ecologcal Evaluaton. Proceedngs of the 18 th CIRP Internatonal Conference on Lfe Cycle Engneerng, pp , Braunschweg, Germany. Perry N, Candlot A, Schutte C Collaboratve Knowledge Networks Emergence for Innovaton. Factors of Success Analyss and Comparson. Journal of Decson Systems 19(1): Ueda K, Nshno N, Nakayama H, Oda SH Decson Makng and Insttutonal Desgn for Product Lfecycle Management. CIRP Annals - Manufacturng Technology 54(1): Xu Y, Bernard A. 2010a. Knowledge value chan: an effectve tool to measure knowledge value. Internatonal Journal of Computer Integrated Manufacturng 23(11): Xu Y, Bernard A. 2010b. Measurement of enterprse knowledge by state characterzaton. Expert Systems 27(5): Xu Y, Bernard A Quantfyng the value of knowledge wthn the context of product development. Knowledge-Based Systems 24(1):