1 PAPER ID 2 Desig for Customer Sustaiable Customer Itegratio ito the Developmet Processes of Product-Service System Providers Alexader Burger, Vitalis Bittel, Ramez Awad, Jivka Ovtcharova Istitute for Iformatio Maagemet i Egieerig, Karlsruhe Istitute of Techology (KIT) Abstract The importace of itegrated product-service provisio bee well-recogized i both academia ad idustry alike. However, substatial deficiecies still ca be foud i the areas of itegrated product-service-developmet ad customer itegratio. The approach Desig for Customer postulated withi this paper highlights a possibility for cotiuous customer itegratio durig the utilizatio pes of a product-service system eablig a costat portfolio aligmet accordig to customer requiremets. Idex Terms Product-Service Systems, Product-Service Developmet, Customer Requiremets Maagemet, Cofiguratio Maagemet I. INTRODUCTION CTUAL chagig market costraits result i a Aaggravated iteratioal competitio as well as i the subsequet homogeizatio of the offered products regardig techical ad qualitative aspects. I additio, customers icreasigly demad itegrated solutios fittig their very idividual eeds istead of buyig stadardized physical products . Cosequetly, typically product-cetered maufacturig compaies ecouter the eed to serve each customer i a more idividual way ad thus to set up differetiatio potetials i compariso to competitors. Oe way of doig so is to offer itegrated value budles ofte referred to as product-service systems (PSS) as they cosist of itagible services ad physical products . Thus, what the customer buys is ot a simple product or a simple service aymore but istead a problem solutio or some kid of busiess fuctioality . I cosequece, product ad service compoets are becomig itertwied ad ew hybrid Mauscript received Jauary 8, 20. The authors are all withi the Istitute for Iformatio Maagemet i Egieerig, Karlsruhe Istitute of Techology (KIT), Karlsruhe, Germay Dipl. Wi.-Ig. Alexader Burger (phoe: ; Dipl. Iform. Vitalis Bittel (phoe: ; Dipl. Wi,-Ig. Ramez Awad (phoe: ; Prof. Dr. Dr.-Ig. Jivka Ovtcharova (phoe: ; structures for a idividual solutio busiess arise. Such a step is accompaied by a chage i the vedor s self-coceptio from maufacturer to solutio provider. The solutio provider beefits from a icreased differetiatio potetial as well as from a icreased customer proximity. The customer o the other had profits from a added value brought by a itegrated product ad service offerig  . Cosistetly, most compaies surveyed i a study regardig their future strategic directio pla to expad their solutio busiess. 98% of the compaies ited to drive their busiess by offerig itegrated value budles istead of pure products . However the trasformatio from maufacturer to solutio provider is associated with multiple efforts. Thus, the itegrated developmet of products ad services requires a complete reewal of product developmet processes i order to provide a added-value to the customer. Yet, withi idustrial practice, oly half of all compaies are sychroizig their products ad services already withi the developmet pe  2. O the other had, solutio providers eed to establish a ituitio about the real ecessities of each customer i order to serve i a idividual way. Thus, the customer eeds to be icorporated ito the processes of the solutio provider holistically. Actual studies however exemplify a utilizatio of classical ad hads-o methods for customer icorporatio ad customer requiremets aalysis. Cosequetly, almost half of all compaies are usatisfied with the idetificatio of the customers eeds ad requiremets  3. The preset paper gives assistace i the addressed topic ad proposes a ew approach for cotiuous customeritegratio also beyod the developmet pes of products ad services. The formal capturig of customer kowledge evisioed withi the approach eables a costat feedback stream of customer requiremets ito the solutio provider s developmet processes. Thereby the approach is supported by referece models eablig a sychroized product ad service developmet utilizig the acquired customer feedback data. page 8 2 page 33 3 pages 23f
2 PAPER ID 2 II. MOTIVATION Due to the short history of product-service systems research, this area still exhibits maifold research questios as already briefly outlied withi the first chapter. The icetive for the preset work is rooted withi some of these ope questios which will be discussed i the followig chapter. A. Need for pre-defied itegrated solutio portfolios Withi idustrial reality, the plaig ad developmet of the product busiess as a historical core competece of maufacturers is based o methodically established foudatios ad follows a structured way. I cotrast, deficits ca be foud regardig the rage of services sice methods ad tools for a structured plaig ad developmet of itegrated product-service-budles are oly provided to a iadequate extet. Therefore, the developmet of the budles withi idustry happes i a ustructured way ad ad hoc i respose to specific customer requests. I doig so, the fact that the ecoomic success of a product-service system is sigificatly depedet o its coceptio is cosidered oly to a iadequate degree. Appropriate process models for the structured plaig ad developmet of product-service systems are the focus of research sice a few years. A detailed state-of-the-art report regardig existig process models ca be foud i .It is the purpose of such process models to support the developmet of a PSS i a structured maer ad i repeatable high quality . However, their high level of abstractio prohibits a easy adoptio i idustrial eterprises. Yet, a more cocrete support is provided whe usig coceptual models for both plaed ad existig productservice systems. As the coceptual modelig is a time ad cost cosumig effort, it is reasoable to use existig referece models as a startig-poit for deducig coceptual models ad adaptig them to the compay s eeds. Referece models provide best-practice processes, which ca be adapted to aid compaies i desigig ad operatig their busiess. Accordigly, referece models are used whe quickly adaptable basic cocepts for implemetig busiess processes ad a speed up of the desig of iformatio systems are eeded . Thus, adaptig referece models ca lower a compay s risk to adapt potetially usuccessful ad overified cocepts. Takig ito cosideratio the ature of product-service-systems, such referece models eed to satisfy requiremets derived from physical products (), requiremets takig ito cosideratio the specific characteristics of services (2) ad fially special modelig requiremets dealig with the itegratio dimesio of products ad services (3). While the use of such referece models i the area of product ad service developmet is geerally accepted, this research field regardig product-service systems is still i its ifacy. Oly five referece models dealig with itegrated PSS could be foud i the scope of a comprehesive literature review. Compared to the more uiversal referece models foud i the maufacturig ad service sector, most of these Referece model Proposed by Year Source PSS Metadata Referece Abramovici 2009  Model Laguage-based ServPay Becker 2008  Model Quality Iformatio System Hoffma 999  Itegrated Iformatio Mertes 200  Processig Quality Iformatio System Schildheuer 998  Table : Existig PSS Referece models listed by author, publicatio date ad publicatio source models ivolve specialized areas oly, such as Quality Assurace or Facility Maagemet . Solely the referece model proposed by Abramovici et al.  deduced from ISO also kow as STEP stadard (STadard for the Exchage of Product model data) - applicatio protocol 24 , as well as the model proposed by Becker et al.  cotemplate a more geeralized view o PSS developmet. Yet, the model proposed by Abramovici still focuses o product iformatio ad eglects the special characteristics eeded for desigig services as well as the temporal developmet. O the other had, the model proposed by Becker focuses more o services ad the customers willigess to pay for these services. Table itemizes the existig referece models for PSS developmet. Hece, the developmet of such referece models eeds to be pushed i order to provide practical ad hads-o support for PSS providers. B. Need for sustaiable itegratio of customer requiremets ito the solutio desig pe Developmet departmets carry a heavy resposibility by determiig product ad service characteristics which affect huma lives ad compay processes o a day-to-day basis . That is why customer iformatio to be ecessarily cosidered whe desigig ew products ad services. Withi classical product developmet, the customer iformatio geerally is collected by askig questios regardig features ad prefereces of a already developed product as exemplified by Clausig  or Ulrich ad Eppiger . Eablig the itegratio of the customer iformatio ito a compay s developmet processes as customer requiremets, a three step procedure to be followed. The desigated steps iclude the Requiremet Elicitatio (), the Requiremets Aalysis (2) ad fially the Requiremet Specificatio (3). Each step is supported by desigated methods which iclude, for example: Kasei egieerig , the Kawakita Jiro (KJ) method  or the Kao Model  for a psychology-based Requiremets Elicitatio; Cojoit Aalysis , Aalytical Hierarchical Processig (AHP)  or Fuzzy AHP  for Requiremet Aalysis; various modificatios of Quality Fuctio Deploymet (QFD)  for Requiremet Specificatio. The utilizatio of these methods is depedet to the purpose ad cotext of use. A detailed state-
3 PAPER ID 2 of-the-art report regardig available methods dealig with customer requiremets maagemet ca be foud i . Nevertheless, these methods restrict themselves to distict poits withi product developmet solely with fixed milestoes for customer icorporatio. Cotiuous ad steady customer itegratio is ot evisioed as the effort for creatio ad aalysis is all too time cosumig. The more, a sustaiable adjustmet of the gathered requiremets also beyod developmet processes spaig the whole lifecycle is ot cosidered at all. Yet, due to a icrease of market shifts i shorter periods of time, also the utilizatio pes of a product s ad service s lifecycle have to be take ito cosideratio as both products ad services eed to be adjusted to chagig market eeds cotiuously. These lacks prohibit a easy adoptio of the methods for a itegrated product-service developmet. Here, the customer as focal poit to be cosidered i a more holistic ad profoud way. That is why a sustaiable itegratio exceedig the developmet processes ad also regardig the usage pes as well as a cotiuous itegratio compared to puctual ivolvemet to be followed ecessarily. Adequate process models for the developmet ad provisio of itegrated solutios are uder developmet for a couple of years as also empized i the previous chapter. Nevertheless, steps from customer aalysis to solutio egieerig ad provisio are rather ot viewed i detail withi these process models, but see as atural ad thus give output of the cooperatio . If explicit methods for these steps are addressed, oly existig methods from product developmet are touched o withi the available process models. However, as customer iformatio becomes more ad more vital, additioal effort withi the field of academic product-service research for the cotiuous itegratio of customer requiremets ito PSS processes to be provided. The target of this research is the provisio of methods ad techologies facilitatig the hadlig of customer iformatio i a structured ad reusable maer. These methods eed to eable a steadily customer requiremets aalysis also after the determiatio of the developmet processes. C. Need for trasparet solutio cofiguratio It is the iheret claim of customer solutios to satisfy customer-specific ecessities. I doig so, it is o loger the customers duty to fid the product most suitable for their desires. This task is passed over to the solutio provider who eeds to be able to uderstad the customers ecessities ad provide the most suitable solutio specificatio i a trasparet fashio. Ayhow, covetioal cofiguratio approaches are ot always directly uderstadable for the customer as they focus the maufacturers atural viewpoit. Accordig to prevalet literature, the product cofiguratio describes the compositio of a product from preset product compoets (so-called selectio ad combiatio) ad the selectio of specificatios of the compoet properties (called parameterizatio) i accordace with the cofiguratio rules  4. This defiitio demostrates that traditioal product maufacturers presume the customer to have a extesive kowledge about the cocered area of expertise. Especially i busiess to customer (B2C) area, this assumptio is associated with a itese examiatio effort for the affected customers. As a result, covetioal product cofigurators exhibit a high termiatio rate due to coceptual gaps for supportig the customer i the decisio-makig process  5. Although this gap is well kow i idustry, oly few approaches dealig with this topic ca be foud. Therefore, more customer-orieted approaches have to be developed, facilitatig trasparet processes for customer iteractio. The customer eeds to be able to express his eeds ad desires without ecessarily havig specialized product kowledge, eablig the direct expressio of the customer s requiremets. The subsequet traslatio of the customer statemets ito product characteristics the is task of the solutio provider eablig a decrease of customer effort durig the specificatio pe. The solutio provider therefore eeds to be able to hadle the additioal effort effectively. That is why o-supervised methods for the trasformatio of customer statemets ito product characteristics are eeded which icorporate the atural fuzziess of customer iformatio. III. THE DESIGN FOR CUSTOMER SOLUTION APPROACH The approach preseted i this paper builds upo the Product-Service Systems Egieerig (PSSE) methodology proposed by Weber, Steibach & Botta [29,30,3] as well as its cotiuatio proposed by Thomas, Walter & Loos . These methodologies represet the most comprehesive frameworks for itegrated product-service systems developmet existig up to ow. I particular, the Desig for Customer approach uses the distictio of structuredescriptive characteristics ad behavior-descriptive properties postulated i both methodologies metioed above. The distictio betwee characteristics ad properties thereby is prescribed as follows: Characteristics defie the PSS from a costructive poit ad may be determied directly by the developer. The properties of a PSS o the other had describe the behavior of the products ad services iheret i a PSS ad may be iflueced i a idirect way oly. However, the properties are to be observed directly by a customer whe usig a PSS. Also, the properties costitute the actual eeds ad requiremets of a customer i a customer-specific laguage. Based upo the disjuctio betwee properties ad characteristics ad i coherecy with the outstadig research questios deduced i chapter 2, the followig research goals of the Desig for Customer approach ca be proposed: Provisio of referece models for itegrated product- 4 page 4 5 page 45
4 PAPER ID 2 service systems eablig a structured developmet ad provisio of PSS i a repeatable high quality. These iformatio models eed to be able to support existig ad upcomig process models for PSS developmet. Provisio of methods ad tools for steady ad cotiuous customer itegratio ito PSS developmet processes usig the atural process itegratio of the customer. The approach thereby focuses the specificatio ad usage pe of productservice systems. Trasparet ad customer-cetric solutio cofiguratio eablig the customer to articulate his ecessities regardig a PSS without the eed of havig extesive expert-kowledge i the related area. It is ot the purpose of the preset approach to replace the existig developmet methods postulated by Weber ad Thomas. It may rather be see as extesio of both methods eablig a more comprehesive customer itegratio also coverig the lifetime pes of a product-service system. I doig so, the approach highlights the customer itegratio i a more detailed ad structured maer with the help of iterrelated iformatio models. The approach is divided ito four mai pillars as also show i Figure. These pillars iclude The customer layer eables the itegratio of the customer durig the PSS specificatio ad usage pe based upo a customer-drive solutio cofigurator usig the above metioed properties The PSS developmet layer eables the kowledge represetatio of a PSS s characteristics i form of referece models as fudamet for a structured developmet ad provisio of product-service systems The fuzzy-based rule set as itegratio layer betwee solutio provider ad customer eablig a traslatio betwee customer-specific properties ad provider-specific characteristics The feedback process stream eablig the steady capturig ad aalysis of customer iformatio ad its direct feedback ito the PSS developmet processes The referece models maily belog to the PSS developmet layer. However, due to their comprehesive ature they are displayed as discrete part of the solutio approach withi Figure. I the followig chapters, the four mai pillars will be illustrated i more detail. However, the focus of the preset paper lies i the presetatio of the fuzzybased rule set depicted i chapter 3.3. A. Customer layer - Kowledge represetatio of the customer Withi the first layer, the kowledge represetatio of the customer is determied. This layer icludes the requiremets Figure : Coceptual Architecture of the Desig for Customer Solutio Approach ad busiess fuctioalities eeded by the customer i order to satisfy his atural ecessities ad is thus ot available i covetioal approaches. The additioal layer eables the customer to specify his eeds without the defiite kowledge of the provider s product ad service portfolio ad thus without specialized kowledge i the affected area. Thus, customer statemets such as I eed assured mobility for at least 30 kilometers a day become possible eve without persoal guidace by sales persoal. The cofiguratio of the appropriate product or service characteristics is the accomplished i the two layers described subsequetly. The itegratio of the additioal layer furthermore allows the customer ot to make a commitmet to a particular product or service right from the begiig. Istead, the most suitable optio will be picked subsequet to his iput. Thus, i the itroduced example the cofiguratio process may offer a pure product such as a car or a itegrated product service system such as a car sharig. The represetatio of the customer layer occurs i a IT-based supported maer eablig the processig of mass data ad its re-utilizatio for Customer Requiremets Maagemet. As the cotet of this layer is highly idividual ad costitutes the compay s very ow core competecies, it eeds to be developed by each PSS provider idividually. Nevertheless, makig this process maageable the associated classificatio model for PSS-properties may be used  6  7  8. This model is defied as commo classificatio system for both products ad services  9. The classificatio model thereby differetiates betwee searchig properties, experiece properties ad trust properties. Searchig properties may be evaluated by the customer a priori. These properties reflect the basic ad origial ecessities of a customer whe searchig ad specifyig the PSS. For example, such properties may cotai aesthetic demads (the customer wats a moder ad exclusive look of the car) or fuctioal oes (the customer eeds a assured 6 page pages 77ff 8 pages 38ff 9 page 68
5 PAPER ID 2 mobility for at least 30 kilometers a day). Experiece properties maifest themselves to the customer oly whe usig the PSS. These properties comprise the de facto behavior of the acquired product-service system (for example the actual maiteace rate or the satisfactio with a fuctioality). Experiece properties become vital if a chage i the chose PSS cofiguratio becomes essetial. Thus, a cotiuous adaptio of a chose cofiguratio to chagig customer requiremets is possible. Trust properties may ot be evaluated directly by the customer. The customer may solely trust i the existece (for example a PSS s accordace with laws ad orms). As a direct evaluatio by the customer is impossible, their further cosideratio withi the scope of the preset approach is ot required. The searchig properties costitute the iterface to the customer durig the cofiguratio ad specificatio pes o the oe had. Durig the usage pe of a solutio o the other had, the iterface to the customer is defied by the experiece properties. Thereby, the cofiguratio of a PSS may alter over time eablig a adaptio to a customer s chagig ecessities. Based upo the customer s decisios, the characteristics adequate to the selected properties may be chose. This is doe automatically usig the fuzzy-based rule set described i paragraph 3.3. Yet, the kowledge represetatio of the PSS characteristics will be depicted i the followig paragraph. B. PSS developmet layer - Kowledge represetatio of itegrated product-service developmet The layer for itegrated product-service developmet eables a structured developmet ad provisio of itegrated product-service systems based upo a itegrated referece model for both product ad service developmet. Thus, the model forms the bodywork for the approach from costructive poit of view, as the characteristics are maifest for both the offered products ad services. Nevertheless, the referece model also builds upo the distictio betwee properties ad characteristics as proposed by Weber ad Thomas i order to support the preset Desig for Customer approach i a formal way. The model pays particular attetio to the equal hadlig of product ad service domai sice major deficiecies withi existig referece models ca be foud i this poit. Aspects are icorporated from the existig more service-orieted approach proposed by Becker . From a more productorieted poit of view, facets from the ISO 0303, applicatio protocol AP 24 , ad thus from Abramovici  are derived. Icorporated requiremets iclude a modular desig, cosideratio of temporal dyamics of customers choices, iterdiscipliary of the affected tasks ad ecoomic quatifiability. Particular attetio was also paid to customer orietatio which is fudametal for the preset approach. Therefore, the model is divided ito a geeric model for Customer property express Customer ows Needs Priorities actuates m Cofiguratio rule refers composed PSS Customer istace PSS Customer Istace Versio Price m Product Product-Service System PSS Module PSS Item Is a Module taxoomy Service Item taxoomy m Requiremet Item Versio Figure 2: Core model of the applied referece model for itegrated productservice developmet geeral PSS developmet ad a customer-specific model icludig the customer istace ad the expressed properties. Formal requiremets of the model iclude the system-orieted ad system-idepedet represetatio, redudacy-free modelig, ituitiveess ad scalability. The model is desiged usig Etity Relatioship Modelig (ERM); particularly the Che-Notatio  for ER modelig bee applied. Besides the core model show i Figure 2, the model cosists of four additioal partial models for product developmet, service developmet, ad two additioal models for customer itegratio. However, the partial models will ot be described i the scope of this paper. Usig the preset model, a systematic ad equal developmet ad provisio of both products ad services is eabled. The model thereby provides the characteristics appropriate to the customers properties. The itercoectio betwee properties ad characteristics is established usig the fuzzy-based rule set postulated i the subsequet paragraph. C. Itegratio layer - Fuzzy-based rule set supportig huma ucertaity A adequate model is eeded for the iterrelatio of properties represetig the customer s viewpoit o the oe had ad the characteristics represetig the viewpoit of the solutio provider o the other had. This model eeds to support the followig costraits: Costrait : The model eeds to support the hadlig of atural huma fuzziess as customer statemets are ofte vague ad ambiguous. Costrait 2: The iterrelatio betwee properties ad characteristics eeds to be trasparet for both the customer ad the solutio provider. Based upo these costraits, a aalysis of established
6 PAPER ID 2 approaches for rule-based systems was carried out. As possible alteratives, Bayesia ets, Fuzzy systems ad Neural ets where examied regardig their degree of performace agaist the debated costraits. Bayesia ets follow the Bayesia probability theory ad are therefore scietifically based o a uique axiom system. The ets are self-learig if logical values of distict statemets after becomig kow successively. Ayway, a high degree of data processig capabilities are eeded, as a large set of coditioal probabilities eeds to be determied. The more, implicit coditioal idepedece is assumed ad esciece may ot be represeted as the value of a thesis h is always mius the value of its atithesis, or as formula:. For this reaso, fuzziess related to huma beigs is ot processable  0. Fuzzy systems are expadig traditioal Boolea logic to the cotiuum of grades of membership betwee 0 ad which makes them able to support fuzziess related to huma beigs . They are storig their kowledge i a structured way i the form of rules so their fuctioality may be recostructed ituitively. However, they are ot directly selfadaptive which meas that rules or fuzzy sets may ot be geerated from sample data automatically  . Artificial Neural Networks are ets out of artificial euros dedicated to have a learig ability similar to the eurocyte cross-likig of brai ad spial cord. I doig so, they are able to self-adapt from the scratch. Ayhow, the stored kowledge is ustructured ad icomprehesible . I may cases, a covergece of fuctios depedet o their iput data is ot observable or to a mior degree oly  2. For the preset use case, eural ets cosistig of oe iput layer ad oe output layer would be eeded which makes them too labor-itesive to apply. Based o this aalysis, a Fuzzy system was chose for the iterrelatio of the customer-drive properties ad the provider-drive characteristics. The Fuzzy process model thereby compreheds five process steps eablig the trasformatio of the fuzzy-based rule set ito mathematical fuctios. The five steps of the Fuzzy process model imply () the fuzzificatio of the properties usig membership fuctios, (2) the aggregatio discrete properties allegorized by the Fuzzy-Ad-coectio withi the premise, (3) the implicatio usig a adequate implicatio operator, (4) the accumulatio of the differet rules beig addressed ad (5) the defuzzificatio resultig i uique output parameters. Usig the emergig mathematical output parameters, the adequate PSS characteristics may be iterrelated to the properties give as iput by a customer i a quatitative maer. I the followig, the five process steps will be depicted i more 0 pages 48ff pages pages 3ff detail. At first, the ecessary variables declaratios will be accomplished. Thereby, the customer properties are declared as N-dimesioal Fuzzy-vector,, () withi the vector space with represetig the Cartesia product operator. The uiverse of discourse of is give by atural huma statemets. For example, a model variable ca be declared as Aesthetic Desig of a car. The, the customer-specific property vector with the chose properties is,, (2) Furthermore, the properties are assessed by the customer usig a predefied set of liguistic variables represetig the customer s ratig of property. For each property, liguistic values, are defied as follows: There are liguistic values, for each customer property with,2,,. The liguistic values, i coectio with a customer s property are formig facts, which express the customer s midset related to the property. The characteristics are defiig the PSS from a costructive poit ad directly determied by the developer. They are defied i aalogy to the customer properties. The characteristics of a PSS are a M-dimesioal Fuzzy-vector,, (3) withi the vector space, with represetig the Cartesia product operator. For each model variable there is a actual characteristics variable represetig the PSS characteristics associated to the customer s properties,,. The customerspecific characteristics value the is,, (4) I aalogy to the customer properties, liguistic variables, for each PSS characteristic with,2,, are defied eablig facts i the form,. This eables the creatio of a fuzzy-based rule set cosistig of rules,2,,. A geeral fuzzy rule relatig to a umber of customer properties with liguistic variables,,2,, ) to product characteristics with liguistic variables,,2, ca be expressed as:
7 PAPER ID 2 :,,,,,, Fuzzificatio For each fact, chose by the customer there are membership fuctios assigig membership values, to each liguistic variable, belogig to a customer property. A mappig relatio is defied as,,,,,,2,, (6) whereby,,2,, is from the iterval 0,., represets the safety degree of the Fuzzy set. Aggregatio The aggregatio represets the Fuzzy-Ad-coectio withi the premise of a Fuzzy-rule. The value,,, is the result of the premise of a rule, which meas the If-Part of the Fuzzy-Implicatio. Choosig the Miimum-Operator as possible alterative for the aggregatio s AND-operatio,,,, results i:,,, mi,,, (7) mi,,,, Implicatio The value,,, eeds to be coected to the membership fuctio,l,2,, related to the PSS characteristic usig a adequate Implicatio- Operator whereby is from the iterval 0, ad represets the safety degree of the Fuzzy set regardig. As a result, the premise of a rule (cotaiig the customer properties) ad the coclusio of this rule (cotaiig the PSS characteristics) are itercoected. Usig the Miimum-Operator for the Implicatio, the a rule for characteristic results i,,,, mi,,,,,l Accumulatio The itercoectio of all rules, respectively their implicatio results,,,,, occurs by meas of a Or-Itercoectio. I the preset approach, the Max- Operator was chose. As result, we get:,,,, max,,,,,,,, The membership fuctio, represets the result of (5) (8) (9) the evaluatio of all rules depedet o the PSS characteristic. I geeral, the membership fuctio delivers a measuremet for the rule base s output value, which is ot utilizable immediately. Defuzzificatio I order to obtai a uique assigmet of the iput variables,, to the output variable, the resultig outcome, of the accumulatio i the form of a surface area yet eeds to be defuzzificated. If all cotets of,,,, eed to be itegrated, the - for the averagig of all rule results the method for the calculatio of the ceter of area (COA) to be chose. This value is calculated as follows:,,,,,,,,, (0) with, from the iterval 0,. The variable, describes the membership of the PSS characteristic to the properties,, etered by the customer. The higher the value of,, the higher product characteristic is itercorrelated with the customer s properties. Thus, a itercoectio betwee customer properties represetig the customers primary ecessities ad the PSS provider s product ad service characteristics was established. The itercoectio cosiders atural huma fuzziess ad delivers quatitative values for the degree of membership betwee properties ad characteristics. Based o these quatitative values, a cofiguratio offer adequate to the customer s requiremets may be submitted by the PSS cofigurator. D. Feedback process stream Adaptatio of PSS portfolio to chagig customer requiremets Beig able to absorb ad store customer kowledge i a formal way usig iformatio techology facilitates its reutilizatio i affiliated processes of the solutio provider. I particular, the customer kowledge may serve as iput for a more customer-orieted product ad service developmet, eablig a direct respodig to the customers chagig eeds. Usig both the customers property iformatio ad the PSS characteristics iformatio, cotiuous o-supervised requiremets aalyses may be carried out. The aalyses represet delta aalyses matchig the elicited As-Is status with the To-Be-status. Ecouterig sufficiet support or critical mass for a particular delta, Egieerig Chage Requests (ECR) are created by the system automatically. These Egieerig Chage Requests costitute workig istructios icludig the compoet accoutable for the delta. Thereby, a distictio betwee several use cases becomes ecessary.
8 PAPER ID 2 I the first case, the aalyses may discover major discrepacies origiatig withi the customers searchig properties. I geeral, this case determies if the solutio provider covers all customer or market treds withi his portfolio. Three subcategories may be differetiated: Case.: The customer chooses the characteristics accordig to his etered properties offered by the system. No actio is required, sice As-Is ad To-Be status are coform with each other. Case.2: The customer chooses differet characteristics as proposed by the system. The reaso for a icorrect propertycharacteristic-iterrelatio either may lie withi a icorrect mappig etered ito the system or withi chagig customer requiremets. I the latter case, this tred becomes oticeable very gradually. Exemplary, more ad more customers will buy electric cars istead of eergy-savig petrol-drive cars whe eterig the property evirometal impact is importat. Case.3: No characteristics mapped to the etered properties are foud. Ecouterig sufficiet support, this status idicates that a customer tred is ot icorporated withi the solutio provider s product ad service portfolio. I the secod case, the aalyses may discover major discrepacies origiatig withi the customers experiece properties. Deflectios withi this case geerally may discover quality deficiecies as well as chagig customer eeds. Case 2.: Customer satisfactio for the acquired products ad services is above or i lie with the customer s expectatios. No actio is required, sice As-Is ad To-Be status are coform with each other. Case 2.2: Customer satisfactio for the acquired products ad services is isufficiet. This may be due to low quality of the offered products ad services or due to chagig customer eeds. I both cases, alterative solutio cofiguratios may be proposed ad adequate actios eed to be performed improvig the quality of the affected PSS items. The aalyses are carried out usig existig techologies from Kowledge Discovery i Databases. I particular, associatio aalyses as well as cluster aalyses ca be used. Associatio aalyses thereby aalyze the iterrelatios betwee elemets of the existig data sets. Commo techologies iclude the A-priori algorithm or its extesio the A-prioriH algorithm eablig the usage of item taxoomies . Cluster aalyses o the other had are used for subsumig data sets ito groups usig affiity cocepts. Thereby, hierarchical methods beig either agglomerative or divisive are applied such as the sigle-likage clusterig or the k-earest-eighbor heuristic. The more, algorithms usig a iterative partitioig such as the k- meas algorithm are utilizable for the preset approach  . The determiatio of the appropriate support vector for the activatio of a Egieerig Chage Request is highly compay-depedet. Likewise, the resposible departmets (product developmet, service developmet, marketig, sales) proper for each sigle case eed to be defied compayspecific. Methods for the sythesis of the aalyzed customer requiremets ito ew or ameliorated products ad services are provided by the process models proposed by Weber  ad Thomas . IV. CONCLUSION Substatial progress bee achieved i the areas of product-service provisio over the last years. However, substatial deficiecies still ca be foud i the areas of itegrated product-service-developmet ad customer itegratio. The preset paper highlights these deficiecies ad proposes a cocept for cotiuous customer itegratio usig a ovel cofiguratio approach based o the distictio of properties ad characteristics. Usig the elicited customer iformatio as trigger for product ad service developmet, a costat adjustmet of the offered product ad service portfolio accordig to chagig customers requiremets ca be carried out. The expasio of the itroduced approach usig sematic techologies eablig a more holistic elicitatio of customer kowledge yet is a future research step. V. 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