Module partition process model and method of integrated service product

Module partition process model and method of integrated service productHao Li a ,b ,Yangjian Ji a ,*,Xinjian Gu a ,Guoning Qi a ,Renzhong Tang aa Department of Mechanical Engineering,Zhejiang University,Hangzhou,310027,PR ChinabSchool of Mechanical and Electric Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,PR China1.IntroductionAs environmental pollution and unsustainable development intensify,so do people’s needs for environmental protection and sustainable products.From this demand comes the emergence of a new strategy:product-service system (PSS),which changes tradi-tional product and consumer offering patterns.This strategy aims to integrate tangible physical products and intangible services to achieve a minimum environmental load and sustainability [1,2].At the same time,the enterprise provides the user with value-added services,achieves more sustainable profit,and enhances the competitiveness of the enterprise [3].With the development of research on PSS,the popular understandings for PSS are:satisfy customers’needs,create more value and make low environmental impact.Various phrases in the literature:‘‘functional sales/economy’’,‘‘integrated product-service offerings’’,‘‘product-to-service’’and ‘‘product-service systems’’all refer to this concept [4].Goedkoop et al.[1],Mont [2],Manzini and Vezzoli [5],Brandstotter et al.[6]and Wong [7]analyzed the concept of PSS,Baines et al.put forward three types of PSS systems:product-oriented PSS,use-oriented PSS and result-oriented PSS,which has become the popular classification of PSS [8].In recent years,the users show more and more requirements for the personalized product and service [9,10].Individualized and changeable products and services inevitably cause cost increases in enterprise management,design and manufacture and the supply chain [11].The modularization of physical products and services can solve the conflicts between personalization and low cost.By establishing a series of standard physical modules and service modules,it can simplify product internal structure and reduce production cost and environmental impact;through the combinations of modulars,it can achieve a variety of physical products and services,and satisfy the customers’personalized needs [12].However,the modularization offering of physical product and service needs to be realized through the modular design platform [9],and the Baines classification of PSS cannot meet the needs of establishing the modular design platform [8].For example,product-oriented PSS may have pure physical products or ‘‘physical product plus service’’,but due to complex relationships between physical products and services,larger differences may exist between pure physical product modular-ization principle and ‘‘physical product plus service’’modulariza-tion principle,which makes it impossible to establish a uniform product-oriented PSS modular design platform.Therefore,the reclassification of the PSS is needed to establish an adaptable modular product platform.Computers in Industry 63(2012)298–308A R T I C L E I N F OArticle history:Received 20July 2011Received in revised form 15February 2012Accepted 16February 2012Available online 6April 2012Keywords:Integrated service product Physical product Product serviceProduct-service system Module partitionQuality function deploymentA B S T R A C TDue to customers’constantly increasing demand for personalized products and services,manufacturing enterprises must provide more diverse physical products and services in the product sale stage.However,the massive diversity of personalized products and services offered leads to the internal diversification of products and services,which greatly increases production costs.The application of the modular method can effectively improve the reusability of a product or service,and reduce internal diversification of the product and service.In this paper,the interactive modular design process is established by the analysis of the relationship between a product or service of integrated service product (ISP)and the analysis of the physical module and service module.This paper deals with the module partition principle of ISP,puts forward the three-stages module partition processes and methods,mainly including service module partition processes based on the ‘‘Top-Down’’and ‘‘Bottom-Up’’methods,the physical module partition process based on the ‘‘Top-Down’’,and the module partition methods based on Quality Function Deployment and mapping matrix.Finally,a case study is done on an electric power transformer using proposed principle and methods,and the processes and methods can achieve the interactive module partition of ISP.ß2012Elsevier B.V.All rights reserved.*Corresponding author.Tel.:+86057187953242.E-mail addresses:lh9666@ (H.Li),mejyj@ (Y.Ji),xjgu@ (X.Gu),gnqi@ (G.Qi),tangrz@ (R.Tang).Contents lists available at SciVerse ScienceDirectComputers in Industryj o ur n a l ho m e p a g e :w w w.e l s e vi e r .c om /l o c a t e /c o mp i n d0166-3615/$–see front matter ß2012Elsevier B.V.All rights reserved.doi:10.1016/pind.2012.02.015In order to establish the customer personalized modular product platform,the author puts forward the concept of‘‘integrated service product(ISP)’’in Refs.[3,13],pointing out that:in product sales stage,to meet the clients’multi-level needs,the manufacturer provides customers with‘‘physical product plus service’’service packs;whereas,physical product is the carrier of product service, and product services are function added and the value added for the physical product.However,since the ISP combines characteristics of both physical products and services,it becomes the most complex product type.In module partition process,how to effectively and reasonably divide the modules of ISP has become the most pressing problem to be solved in the product design.This paper deals with a module partition methodology of ISP. The second section briefly reviews the existing design method for ISP.The third section analyzes the product modularization design of ISP,as well as the relations between the product and service,and related concepts.The fourth section analyzes the module dividing principle of ISP.Thefifth section puts forward a three-stage process for module partition,and provides the realization method at each stage.Finally,a transformer case is used to show the feasibility of the related methods.The discussion and summary show the significance of the described process and methods,as well as limitations and future prospects.2.An overview of related research2.1.Research progress of PSS designIn recent years,the environment and sustainable development have become of increasing concern to both producers and consumers. Thus,PSS has attracted great interest from industry and academia as an important means for sustainable product development[1].PSS design is the most important stage in the realization of PSS,and has become a hot research spot in thefield of PSS.Scholars have proposed a set of methods to support PSS System design,such as Kathalys PSS method[14],sustainable product and service development method[15],Methodology for PSS develop-ment[16],and the product-service blueprint method[17].These methods provide specific design frames,PSS development processes,implement tools,and play important roles in service design process and PSS implementation.However,research on product and service integration design theory and on the overall scheme description is still lacking[18].For this issue,Aurich put forward the design methodology for integrated products and services system development,the result reflects the interactive design of product and service[19].Ge et al.put forward product/service integration design methodology based on the axiomatic design theory and the fault tree analysis[18].Zhang et al.put forward the product/service overall design of full product, and proposed variational configuration model of full product based on general bill of material[20].These studies make up for the research deficiency on the design methodology of integrated products and services,and provide PSS design with technical support.2.2.Research progress of PSS modular designFor the research on physical product modulization,many scholars such as Aoki[21],Pahl and Beitz[22],Suh[23],Tong[12], Li[24],Hou et al.[25],Qi et al[9],Erixon et al.[26],Tseng and Jiao [27],Dahmus et al.[28],Gu and Sosale[29],and Fan et al.[30],have already built a mature system of modularization theory and methodology.The main methods used in the physical product modulization are:the design structure matrix,genetic algorithms, the quality house matrix,the functionflow model,simulated annealing algorithms,the axiomatic design theory,clustering algorithms,and complex networks[9,12,21–30].These methods aim at the particular stage of the product life cycle,and make physical product module division more quantitative.For the intangibility and changeability of the service product,Li divided the service modularization into content modularization and process modularization,interfaces between modulars are more loose than interfaces between industry product modules [31].Guan put forward a module partition method based on service blueprints and functionflow[32].Deng put forward the basic characteristics and processes based on the module combina-tion offinancial service innovation[33].The abovefindings refine the service module partition and make it more concrete.With the emergence of PSS strategy,the traditional module partition methodology needs to be expanded[34].With the customer’s increasing personalized needs for products and services, the product offering and system implementation of PSS become more and more complex.Therefore,the modular strategy for products and services has been applied to reduce the complexity of product engineering.In order to improve the product and service potential,Aurich gave a modular principle to realize the technical PSS,and put forward a process library used to design and manufacture module technical PSS[35].Wang deeply investigated PSS parallel modular development and the relationship between the physical products and services,and used QFD method and portfolio technique to complete PSS module development[36].According to the above studies,many scholars have made great advances in physical product modularization,service modulariza-tion,integrated design of ISP,but mainly from the perspective of strategy,management,and process.Up to now,the research on the modular design methodology of ISP is still minimal,and the influence relation analysis between physical product and service has not been revealed.Therefore,the key question remaining in the field is how to solve ISP module partitioning.3.The modular design of ISP3.1.Understanding the relationship between the product and serviceISP includes physical products and services,and the relation-ship between physical products and services can be analyzed from the product structure(Fig.1).According to the correlation degree of physical products and service,service can be divided into functional service and non-functional service.A functional service is a type of service which needs to be completed with specific physical components for support,includ-ing maintenance service,remote monitoring,etc.,and these services will directly affect the function and structure of physical product.Non-functional service is independent of the function physical module,including consulting service,installation service, transportation service,training service and so on.As shown in Fig.1,functional services can be carried out when the special optional physical component assembled in the physical product; but the non-functional service can be carried out without the physical component.Therefore,ISP design not only considers the service-oriented physical product design,but should also take into account service design based on the physical product,so ISP design is the integrated design process of physical product and service.3.2.Physical module V.S.Service module3.2.1.Physical moduleFor the traditional physical product,many scholars have given definitions of the‘‘physical module’’[21–26],but there is still no unified standard definition and the popular view is the definition from Masahiko.He described the module as a kind of semi-self-disciplined subsystem with independent function that couldH.Li et al./Computers in Industry63(2012)298–308299constitute a more complex system through a standard interface and semi-self-disciplined subsystems according to interrelated rules [21].3.2.2.Service moduleDefinition 1:Service module.Service module is the abstraction from tangible service or intangible service with independent function,and it realizes service functions through the interaction of physical modules and services process.Tangible service meets customers’specific needs by providing physical product or parts,for intangible service,the service process or result does not provide physical products or parts.According to the coupling degree between the service module and the physical module,the service module is divided into functional service modules and non-functional service modules,whose differences are shown in Table 1. Definition 2:Functional service module.A functional service module can realize specific functional services with the support of some physical modules.It has a close relationship with particular physical modules,such as remote monitoring service,which can be used by installing the corresponding monitoring parts to the physical product if necessary.Definition 3:Non-functional service module.A non-functional service module has not strict relation to the physical product,and it does not depend on the specific physical module,such as installation service,transportation service.3.3.The modular design of ISPThe modular design of ISP is shown in Fig.2.Before the product’s formation,we must establish a modular platform oriented to service configuration.Through this platform,we can configure out personalized ISP.The basis of the establishment of amodular platform is to finish the modular design of ISP and build a product main structure.In the phases of customer demand,concept design,and detailed design,customers’needs should be collected and converted into technology characteristics and service requirements.Service requirements include functional services and non-functional services,and form the service module structure through the module partition.In the modular design of the physical product,through the analysis of technical features and functional service,the physical module structure is con-structed by using an appropriate module partition method.Finally,through the association rules,the main structure of ISP can be set up,and the modular platform oriented to service configuration can be formed.4.Module partition process and method of ISP4.1.The common form of service moduleThere are three forms of service modules:independent function service modules,‘‘class’’service modules and process service modules [37,38].A function independent service module is an independent function corresponding to a physical module or service module.There is a 1:1relationship between function and module,such as the service module of spare parts.A class service module is a class of service with the same characteristics,and these services are grouped to the same service class.This type of service forms a ‘‘class’’services module,such as the main components maintenance service package in maintenance services.A process service module is a service process in a specific phase,which completes some service tasks in a certain period of time or certain stage,such as the lubricating oil company’s overallTable 1Comparison of physical module and service module.ClassificationSubclassTangible or notStabilityModule compositionPhysical module Physical moduleTangible moduleIt is highly stablePhysical module is composed of general modules and special modulesService moduleFunctional service moduleTangible moduleIt can be added or cancelled dynamically Special modules will be neededNon-functional service module Intangible moduleIt can be added or cancelled dynamicallyService module is composed of general modulesPhysical ProductServiceFig.1.The relationship between the product and service.H.Li et al./Computers in Industry 63(2012)298–308300chemicals management module,full performance service module of ABB.4.2.The module partition process of ISPThe development of ISP is a collaborative development process of products and services,which cannot avoid considering the shortcomings of the mutual influence between products and services[36].Therefore,the module partition process of ISP is an interaction process of service module partition and physical module partition,and physical modules and service modules influence each other.The module partition process can be divided into three steps(Fig.3).4.3.The module partition method of ISP4.3.1.The service module partition method based on the‘‘Top-Down’’methodThe service module partitionfirstly uses‘‘Top-Down’’method. In the‘‘Top-Down’’module partition process,service modules can be divided into function related,class related and process related according to the relationship between services,and then a comprehensive correlation matrix is set up through the calculation of correlation between services,and the divided modules can meet the maximum demand.1)Realize the mapping from customer’s requirement to servicefunctionThe customer’s service needs include functional requirement and non-functional requirement,through the Quality function deployment(QFD)can realize the mapping from customer’s requirement to service function.QFD is a kind of product development method derived by customer requirements,and its core content is requirements conversion.The tool of QFD method is the house of quality, which is an intuitive matrix expression form[39].2)The correlation analysis of the influencing factors:(1)Function correlationThe definition of the function correlation is as following: in the service module partition,the services that achieve the same function will be put together as a module,and keep function independence.Correlations exist between service modules,and the closeness of the relationship can be said to be its correlation degree.According to the function correlation between services,it can be divided into several service modules,Table2shows the function correlation evaluation criteria between services.Fig.2.The modular design of ISP.Table2Correlation degree of function-based service module.Description of relation between modules CorrelationcoefficientThe two service modules exist to achieve thesame function,and are indispensable1.0The implementation of one service modulewill affect another module significantly0.7The implementation of one service modulewill affect another module0.5The implementation of one service modulewill affect another module slightly0.3No relations between the two service modules0Table3Correlation degree of class-based service module.Description of association between modules CorrelationcoefficientThe services belong to the same class and achievethe same function,their specifications and propertiesare also the identical1.0The services belong to the same class,and achieve the samefunction,but their specifications andproperties are different0.8The services belong to the same class,but theirfunctions are different0.4The services does not belong to the same class,their functions and properties are differentH.Li et al./Computers in Industry63(2012)298–308301(2)Class correlationThe definition of the class correlation is that some services have the same characteristics,and these kinds of services can be put into the same service groups and form a module,which will facilitate the service management and provide more similar services.According to the class-oriented service correlation,it can be divided into service modules,Table 3is the class correlation evaluation criteria between services.(3)Process correlationThe service module has the time or process continuity,and it will complete the corresponding service tasks in a continuous time.According to service process correlation degree,theservice module partition can be finished.Table 4is the process correlation evaluation criteria between services.3)Establish correlation integration analysis matrixFor the analysis of the entire service modules division,the influence of three factors should be integrated:function,class and process.Through analyzing the correlation coefficient between the services,we obtain the correlative matrix by the Dot Product method:M ¼f m i j g(1)m i j ¼1i ¼jX n1r i j F f þX n 1r i j F c þX n1r i j Fp i ¼j8><>:(2)where r ij is the correlation between the service modules respectively.The correlation determination method of this paper is based on Tables 2–4.F f ,F c ,F p are the weight coefficients of the three partition method respectively,F f +F c +F p =1.4)According to the correlation integration analysis matrix,we can calculate correlation between services and get the service module partition scheme at different levels.User’s service needs (non-functional service)User’s service needs functional service …………Service modularPhysical modular…User’s basic function needsBottom -UpTop-DownTop-DownThe modular product ofISPThe main structure of physical productRequirements S6S1S2S3S4S5m2m3m4m5m6m1service moduleService functionCorrelative matrixm7S7……Modular partition based on function Modular partition based on class Modular partition based on processP h a s e 1P h a s e 2Phase 3m6m1m2m3m4m5p2p3p4p5p6p1Physical modulep7m7……R1R2R3R4R5S1S3S4S5S6S7FunctionS2R1R2R3R4R5F1F3F4F5F6F7FunctionF2Mapping matrix……F1F2F3F4F5P1P3P4P5P6P7Structure moduleFunctionP2Autocorrelationmatrix…………Mapping matrixMapping matrixCorrelative matrixService function AutocorrelationmatrixThe main structure of service productAutocorrelationmatrixRequirements Fig.3.The module partition process model of ISP.Table 4Correlation degree of process-based service module.Description of association between modulesCorrelation coefficientThe service implementation process is continuous 1.0The service implementation process is discontinuousH.Li et al./Computers in Industry 63(2012)298–3083024.3.2.The physical module partition method based on the‘‘Top-Down’’methodThe relevant literature on physical module partition has been reviewed in the section of‘‘An overview of related research’’,and shows that physical module partition is mainly achieved through a four-step approach[9,12,21–30].The physical module partition of ISP is a service-derived module process.In this paper,a detailed process on physical module partition of ISP is given according to the popular four-step module partition approach.Step1:From the user requirements,the user requirements include product basic function requirements and functional service needs.Through the quality function house,the basic function requirements and functional service requirements are transformed into products of total function and sub function, and complete the product function decomposition.Step2:Establish function and structure mapping matrix to divide the physical module.Analyze the correlation of the product substructure in view of function and structure,and realize the mapping of‘‘function domain-structure module domain’’.The product function and structure of the relationship between the module matrices reflect the mapping relationship and related degree between function and structure.The autocorrelation matrix of product structure module represents the influence degree when the module changes into other product structure modules.Step3:Analyze the correlation degree between function and structure according to the function correlation matrix,which can obtain physical module partition schemes from different levels.Step4:Establish the main structure of the physical module according to the relationship between physical modules.4.3.3.The service module partition method based on the‘‘Bottom-Up’’methodThe service modules,such as maintenance warranty service, and spare parts,have close correlation with specific physical modules,but the service content can’t be accurately determined before the accomplishment of physical product design.When the finished physics module is used to determine the specific service module,this is the process moves from bottom to top in the so-called‘‘Bottom-Up’’method.In the‘‘Bottom-Up’’method,according to the divided physical module,the integrality of basic product services and other special services which provide the customer with physical products are evaluated,if not present,add required service modules by the ‘‘physical module-service module’’mapping method.In Fig.3, physical modules are already divided modules,and the needed service modules can be supplied through the physical modules mapping.If the service module does not exist or the module partition is coarse in granularity according to the‘‘Top-Down’’method,then add the service module.Based on the correlation of physical modules and service modules,the service modules can be divided and mapped by analyzing the informed physical module,as shown in Fig.6.The mapping of physical module to service module and the‘‘Bottom-Up’’service module partition mainly contribute to improve the maintenance service.4.3.4.Establish the modular platform of ISPAccording to the module partition procedures and methods given above,the physical module partition and the service module partition can befinished.According to the relationship between the physical module and the service module,one can set association rules between modules(physical modules,service modules,physical modules and service modules),and establish the modular main structure of ISP.5.Case studyCustomer demands for power transformers change greatly,and there are many product services at the stage of sale,operation and recovery.Accordingly,this paper uses the oil-immersed power transformer as an example to prove the proposed principle and method of ISP modularization.5.1.Mine and analyse the customers’requirements1.Customer’s demand:basic functional requirements(1)The demand for electricity consumption.(2)Environ-mental conditions:altitude.(3)Environmental conditions: environmental temperature and cooling medium temperature.(4)Environmental conditions:the level of pollution.(5)Electricpower loss.(6)Partial discharge.(7)The ability to avoid or prevent short circuits.(8)Operating conditions,such as whether to run in parallel with the existing transformer.(9)Using environment.The transformer hasfire prevention requirements, indoor or outdoor,etc.(10)Color requirements.2.Customer’s service demand:functional service requirementsThe functional service of the transformer mainly includes measurement,control,testing,monitoring,protection service, etc.3.Customer’s service demand:non-functional service require-mentsThe non-functional service of the transformer mainly includes: (1)Consulting service.(2)Transportation service.(3)Installation service.(4)Maintenance service pack.(5)Spare parts service.(6) etc.5.2.Module partition5.2.1.The transformer service module partition based on the‘‘Top-Down’’method1.The mapping of transformer product service requirement toservice function based on the quality function house This case only gives37kinds of service,so the service granularities is rough and big,but it can prove the basic theory and methods proposed in the paper.By using the quality function house,it can realize the conversion from transformer product service needs to function(omission).The service function after the transformation are as follows.The preliminary service classification of transformer based on function has beenfinished.Transformer non-functional service are basic services,including technical advice and guidance m1,transportation service m2,installation services m3,guarantee service m4,spare parts m5,semi-finished products and plug-in boards m6,DC resistance measurements m7,voltage test m8,seal test m9,insulating oil test(before the test)m10,finished product voltage and connecting label measurement than group m11,operation test of on-load tap-changer m12,etc.Functional service module includes:temperature rise test analysis m13,thunder impact test(the full wave,carrier wave) m14,temperature rise and insulation oil chromatographic analysis m15,mechanical strength test of oil tank m16,transition characteristic test of on-load tap-changer switching m17, winding degeneration m18,zero sequence impedance measure-ment experiment of three-phase transformer m19,no-load current harmonic measurement m20,sound level measurementH.Li et al./Computers in Industry63(2012)298–308303。