Computers in Industry 63 (2012) 309–318

Development of a knowledge-based design support system forProduct-Service Systems

Fumiya Akasaka *, Yutaro Nemoto, Koji Kimita, Yoshiki Shimomura

Department of System Design, Tokyo Metropolitan University, sahigaoka 6-6, Hino-shi, Tokyo 191-0065, Japan

A R T I C L E I N F O

Article history:

Received 21 February 2012

Accepted 21 February 2012

Available online 6 April 2012

Keywords:

Service Engineering

Product-Service System

Design support

Knowledge

Computer-aided design

A B S T R A C T

Compared to product design, a broader range of knowledge is required to Product-Service System (PSS)

design, since both products and services are included in its design space. In this paper, a method for

knowledge-based PSS design support is proposed. The proposed method is on the basis of the research on

Japanese Service Engineering, which provides design methodology of the integrated provision of

products and services. In addition, a prototype of computer-aided design (CAD) system to realize

knowledge-based PSS design support is developed. The method and system support the acquisition of

new PSS design solutions by integrating knowledge accumulated in a knowledge base. The developed

system was applied to a design of an actual service: an accommodation service in Japan. The application

result showed that the developed system was useful to support a design of the integrated provision of

products and services.

� 2012 Elsevier B.V. All rights reserved.

Contents lists available at SciVerse ScienceDirect

Computers in Industry

jo ur n al ho m epag e: ww w.els evier . c om / lo cat e/co mp in d

1. Introduction

Our society’s limitations of natural resources, energy supplies,and capability to accept industrial waste have led to seriousproblems related to producing and disposing of artifacts [1]. Wehave to immediately search for solutions or business models torealize a sustainable society. In this context, services arebecoming increasingly important in the manufacturing industry,since a longer life or more added value of a product can beachieved by offering services (e.g., a maintenance service)combined with a product (e.g., a car). As a result, new conceptssuch as the Product-Service System (PSS) [2–4], which is definedas consisting of tangible products and intangible services designed

and combined so that they jointly are capable of fulfilling specific

customer needs [2], have been attracting much attention,especially in developed countries.

As pointed out in the product design research, knowledgeobtained from past products and cases provides helpful informa-tion for designers [5]. Therefore, many studies in the productdesign area focus on knowledge-based design support (e.g., [6,7]).

Compared to product design, a broader range of knowledge isrequired to PSS design, since both products and services areincluded in its design space. Therefore, providing knowledge todesigners is the key to enhance the quality of design solutions in

* Corresponding author. Tel.: +81 42 585 8600; fax: +81 42 585 8425.

E-mail addresses: akasaka-fumiya@sd.tmu.ac.jp (F. Akasaka),

nemoto-yutaro@sd.tmu.ac.jp (Y. Nemoto), kimita-kouji@sd.tmu.ac.jp (K. Kimita),

yoshiki-shimomura@center.tmu.ac.jp (Y. Shimomura).

0166-3615/$ – see front matter � 2012 Elsevier B.V. All rights reserved.

doi:10.1016/j.compind.2012.02.009

PSS design. However, few methods and tools for knowledge-basedsupport for PSS design have been proposed.

In this paper, a method for knowledge-based PSS designsupport is proposed. The proposed method is on the basis of theresearch on Japanese Service Engineering, which provides designmethodology of the integrated provision of products and services[8,9]. In addition a prototype of computer-aided design (CAD)system to realize knowledge-based PSS design support is devel-oped. The method and system supports the acquisition of new PSSdesign solutions by integrating knowledge accumulated in aknowledge base.

The remainder of this paper is organized as follows. Section 2explains a definition and modeling methods of services proposedin Service Engineering, which is a fundamental concept of thisstudy. In Section 3, a knowledge-based design support method isproposed. Its overview is reported in Section 3.1. Section 3.2explains a scheme to represent knowledge, and Section 3.3 reportsa scheme to provide knowledge to a designer. Section 4 reports theimplemented prototype system for knowledge-based designsupport. Section 5 explains the results of an application of thedeveloped system. Section 6 discusses the virtues and remainingissues of this research, and Section 7 concludes this article.

2. Service Engineering

2.1. Fundamentals of Service Engineering

The authors have carried out fundamental research on ServiceEngineering in Japan, which aims at providing design methodologyof services from an engineering viewpoint [8,9]. In SE, a service is

Fig. 1. Comparison between terms used in PSS studies and Service Engineering [12].

Fig. 2. Overview of service design methodology proposed in Service Engineering.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318310

defined as an activity between a service receiver and a service

provider to change the state of the receiver [8]. According to ourdefinition, a service is offered to realize the receiver’s state change,and when the state changes to a new desirable one, the receiver issatisfied. Therefore, changing a receiver state is equal to fulfilling acustomer need in this context. This definition includes a broadersense than the typical definitions in the service marketing field,which are used to clarify the difference between services andproducts (e.g., [10,11]). In this definition, we regard a service as acombination of service activities and physical products [8,9]. Theterm service used in this study, therefore, corresponds to PSS(Fig. 1).

2.2. Service design

In a series of Service Engineering studies, methods to design aservice have been proposed. It is noteworthy that a term service

Fig. 3. Models of coffee shop service, (a) service fu

means a combination of service activities and physical products asmentioned above.

Fig. 2 shows the overview of service design methodologyproposed in Service Engineering. A service is modeled as afunctional structure that satisfies customer needs, and specificentities and their activities/behaviors are associated with thefunctional structure ([8,9]). Here, entities include both physicalproducts and human resources, which correspond to product shareand service share in PSS context.

In short, a service can be designed through phases of‘‘development of functional structures’’ and ‘‘embodiment offunctions,’’ as shown in Fig. 2.

2.2.1. Service function model

A service function model represents the realization structureto fulfill customer needs. As shown in Fig. 3 (a), this model consistsof functions, which are described as ‘‘verb + noun,’’ e.g., ‘‘serve + a

nction model and (b) service process model.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318 311

cup of coffee,’’ and entities that have been used in productdesign methodologies (e.g., [7,13]). In this model, preliminaryfunctions that fulfill customer needs are described and thendecomposed into sub-functions. The sub-functions are decom-posed into more concrete functions if needed; and then ahierarchical functional structure is developed. Subsequently,human resources (e.g., staff and customers) and physical products(e.g., machines and facilities) are associated with the mostconcrete sub-functions in the hierarchical functional structure asfunction carriers. For example, in Fig. 3 (a) a preliminary function‘‘Offer coffee’’ is decomposed into two sub-functions ‘‘Makecoffee’’ and ‘‘Serve a cup of coffee’’ and the sub-function ‘‘Makecoffee’’ is embodied by ‘‘Coffee maker (product)’’ and ‘‘Kitchenstaff (human).’’

Here, the function decomposition and embodiment are carriedout by designers on the basis of knowledge that they have. Thismeans that a variety of design solutions can be generated, althoughthe quality of design solution is largely depends on the amount ofdesigner’s knowledge.

2.2.2. Service process model

In the service marketing field, a service blueprint is themost common method used by marketers to visualize serviceactivities in a sequential manner [14]. In Service Engineering,Hara extended the concept of a service blueprint as aservice process model that includes product behavior and itsrelationship to service activities as well as the connectionbetween activities/behaviors and customer needs/values [12](Fig. 3 (b)). The extended service blueprint is basically describedwith time-sequence diagram of human activities and productbehaviors.

A service process model consists of an interrelated activityblueprint and behavior blueprint. Some activities/behaviors in theactivity/behavior blueprint are related to functions in the functionmodels. By connecting the function model and the process model,it is possible to identify what activities/behaviors of the entitiesrealize each function.

2.3. Service CAD

We have developed a computer-based service design supportsystem (service CAD) called Service Explorer [8,9] based on thedefinitions and methods outlined above. The system was initiallydeveloped as a service CAD prototype when we first beganinvestigating Service Engineering and first released to the publicin 2004.

Fig. 4. A concept sketch of knowledge-

3. A knowledge-based PSS design support system

3.1. Overview

This paper proposes a knowledge-based PSS design supportsystem on the basis of the design methodology of ServiceEngineering. In this study, the embodiment phase, where thevariety of PSS design solutions generates, is focused on. Namely,designers’ support in the embodiment phase is achieved byproviding knowledge.

Fig. 4 shows a concept sketch of knowledge-based PSS designsupport system that is developed in this study. This systemincludes PSS design workspace and knowledge base. A PSS isdesigned in the design workspace using service design methodol-ogy proposed in Service Engineering. The knowledge base consistsof knowledge obtained from multiple PSS/service cases. Moreover,a piece of knowledge is described as a set of function and functioncarrier. In this paper, this type of knowledge is called ‘‘FunctionEmbodiment Knowledge (FEK).’’ A designer explores the desiredknowledge from this knowledge base. The desired knowledge issearched on the basis of the similarity between functions, and thedesign support system provides the knowledge in a form of a‘‘catalogue’’ of FEK. This catalogue is called Service DesignCatalogue (SDC) in this study. Function carriers selected from aSDC is combined with a service function model described in thedesign workspace. A PSS design solution is then generated.

It is noteworthy that this system is not automated designsystem but a cooperation system that can supports designers’creation of design solutions by enhancing the amount of designers’knowledge though interactions between designers and the system.

In the following, the details of FEK are explained in Section 3.1.Section 3.2 reports the features of the SDC; in addition, thedifferences between SDC and traditional design catalogue are alsomentioned.

3.2. Representation of function embodiment knowledge (FEK)

3.2.1. Framework of knowledge representation

In the service marketing field, service has been studied with afocus on 3Ps: People, Physical evidence, and Process [11].Additionally, Yoshikawa denotes service in terms of ‘‘manifestfunctions’’ that become manifest through human action or the useof artifacts [15]. These studies emphasize the importance ofconsidering (1) entities and (2) the realization processes offunctions in the embodiment phase. From these viewpoints, theFEK should include 2 elements: entities and realization processes.

based PSS design support system.

Fig. 5. Input–output function representations for service design.

Table 1Functional basis proposed by Hirtz et al. [17].

Class

(primary)

Secondary Tertiary Correspondents

Branch Separate Divide Isolate, sever, etc.

Extract Detach, isolate, etc.

Remove Refine, filter, etc.

Cut, drill, etc.

Distribute Diffuse, dispel, etc.

Channel Import Form entrance, allow, etc.

Export Dispose, eject, etc.

Transfer Carry, deliver

Transport Advance, lift, etc.

Transmit Conduct, convey

Guide Direct, shift, etc.

Translate Move, relocate

Rotate Spin, turn

Allow DOF Constrain, unfasten, etc.

Connect Couple Join Associate, connect

Link Assemble, fasten

Attach

Mix Add, blend, etc.

Control magnitude Actuate Enable, initiate, etc.

Regulate Control, equalize, etc.

Increase Allow, open

Decrease Close, delay, etc.

Control magnitude

(continued)

Change Adjust, modulate, etc.

Increment Amplify, enhance, etc.

Decrement Attenuate, dampen, etc.

Shape Compact, compress, etc.

Condition Prepare, adapt, etc.

Stop End, halt, pause, etc.

Prevent Disable, turn-off

Inhibit Shield, insulate, etc.

Convert Convert Condense, create, etc.

Provision Store Accumulate

Contain Capture, enclose

Collect Absorb, consume, etc.

Supply Provide, replenish, etc.

Signal Sense Feel, determine

Detect Discern, perceive, etc.

Measure Identify, locate

Indicate Announce, show, etc.

Track Mark, time

Display Emit, expose, etc.

Process Compare, calculate, etc.

Support Stabilize Steady

Secure Constrain, hold, etc.

Position Align, locate, etc.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318312

Meanwhile, in this study, FEK is searched on the basis of thesimilarity between functions, as reported in Section 3.1. In thisregard, if the representation of functions is not unified, it is difficultto conduct a thorough and effective search of functions that havethe similarity with the target function [16]. Therefore, using aunified form and vocabulary is required for function representa-tion to increase the efficiency of knowledge retrieval and thereusability of knowledge.

In light of these requirements, we represent a minimum unit ofFEK by 3 elements: function (described with a unified form andvocabulary), entities, and realization processes. The remainder ofthis section explains each element in detail.

3.2.2. Function

Service function represents what is offered in the service. Themajor approaches for describing function are either ‘‘verb–noun’’ or ‘‘input–output’’ [7,16]. The verb–noun approach, whichhas been used in Service Engineering, is similar to the use of anatural language; it is therefore more flexible and easier touse for designers. However, this leads a different expression ofthe same functions. It makes effective knowledge searchdifficult as stated above. Thus, this approach is unsuitable forknowledge management. On the other hand, the input–outputapproach that is used in various fields of design defines afunction as an input–output relation among the material,energy, and signal/information [13]. This approach could helpto coordinate knowledge, although it confines flexibility ofdescription [16].

For these reasons, we adopt the input–output approach todescribe function in FEK (Fig. 5). Input/output elements consist ofmaterial, energy, and signal/information in a traditional way.However, service-typical elements (e.g., human, order, andknowledge) that is not considered in product design are includedhere (the right-hand side of Fig. 5).

Furthermore, we introduce a service function vocabulary list inorder to normalize the lexical expression of functions. Thefunctional basis, as shown in Table 1, which was developed byHirtz et al., organizes the verbs used in the input–output functionrepresentation [17]. It includes specific functions and theirsynonyms in eight categories: Branch, Channel, Control, Magni-tude, Convert, Provision, Signal, and Support (Table 1). In our study,assuming that the functional basis is available for describingservice functions, we use this vocabulary to describe servicefunctions.

In summary, a unified representation of function is realized byusing the ‘‘input–output approach’’ in combination with the‘‘service function vocabulary list’’ in this study. In other words, afunction in FEK is described by 3 elements: input/output elements(material, energy, and signal/information), and a verb (from thevocabulary list).

This proposed function representation method is on the basis ofthe input–output approach that has proposed in the traditionalproduct design area. However, service-typical elements (e.g.,human, order, and knowledge) that is not considered in productdesign are included as input–output elements.

3.2.3. Entity

In the traditional product design researches such as [5,7,13],‘‘entity’’ includes only physical product or its components. Thescope of this study is on the PSS design where services, which aremainly operated by human resources, are designed in addition tophysical products. Consequently, in this study, entity includes bothhuman resources and physical products that construct a service,e.g., staffs, technicians, machinery, and facility. Here, humanresources correspond to service share, and physical productscorrespond to product share in PSS.

Table 2Representation form of FEK (function embodiment knowledge).

Item Content

Function Input elements Material, energy, or signal/information

Function Verb (from the vocabulary)

Output elements Material, energy, or signal/information

Function

carrier

Entities Entity name, type (human or

physical product)

Processes Activities/behaviors

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318 313

As mainly discussed in Ergonomics researches, humans andphysical products (i.e., service and product share in PSS context)have some differences in their features; for instance, flexibility ofcommunication, variety of performance, tiredness, etc. Thus, it isessential that service designers select appropriate entities for eachfunction, taking into consideration the different features ofhumans and products. In this study, therefore, not only a nameof entity but also a type of it are described in FEK, since theybecome one of guideposts when designers select entities.

3.2.4. Process

Service delivery process is a series of tasks that provide value tocustomers. Service function becomes manifest through servicedelivery processes. Namely, service delivery process representshow to provide functions or values. This process aspect is notconsidered as a design elements in the traditional product designresearch.

The service delivery process is different from input–outputfunctions in terms of the level of abstraction. In general, ‘‘function’’is an abstract concept that represents information on ‘‘what isoffered in a service.’’ Namely, a function model does not includeinformation on specific entities to be used in service offering. Onthe other hand, a concept of ‘‘deliver process’’ is more concrete andrepresents ‘‘how the functions are offered.’’ Here, specific entitiesto be used in service offering are already decided. Therefore, thedelivery process model can depicts specific time-sequenceprocesses performed by specific entities, although the functionmodel is a static model and does not include time-sequenceinformation.

In this study, knowledge concerning service delivery processesis described in the form of the service process model reported inSection 2.3, i.e., a process model based on the service blueprintingtechnique [14]. This is because process knowledge representedwith this form can be understood easily without specializedknowledge [12]. This intelligible form is appropriate for knowl-edge-based design support from the following two reasons:

Fig. 6. An example of a SDC (s

� General representation form that does not depend on a specificdomain

Service includes a wide variety of corporate activities. It istherefore supposed that FEK apply to various domains. Conse-quently, a general representation form that does not depend on aspecific domain is appropriate and useful.� Various participants in PSS/service design

To design a PSS or service, various departments such asmarketing, product planning, product design, and softwaredevelopment divisions, need to participate in design coopera-tively. Therefore, the important thing is that all participantsunderstand and use FEK in a common manner.

3.2.5. Summary

As reported in this section, the FEK is represented with 3elements: function, entities, and realization processes. Namely, theFEK is represented and collected in the ‘‘unified’’ form shown inTable 2. A function carrier, i.e., entities and their activities/behaviors, are accumulated together with a service functionmanifested by them. This enables service designers to searchfunction carriers based on the similarity between functions.

3.3. Service design catalogue (SDC)

The design catalogue proposed by Roth and Koller [18,19] intheir product design researches is a collection of workingprinciples, e.g., physical effects, physical mechanism and geomet-ric/material characteristics, to embody functions in product designand regarded as a useful tool to support development of a designsolution [13].

In this study, the basic idea of the design catalogue is adopted toservice design. The traditional deign catalogue is extended to beused for PSS design. The extended design catalogue is called SDC asmentioned in Section 3.1.

The SDC is a collection of working principles of services, whichrepresent the means to embody service functions. As mentioned inSection 3.2.1, in this study, the working principles of services canbe described as FEK. Therefore, the SDC is a collection of FEK (i.e., aset of a function, entities and processes), while the traditionaldesign catalogue is a collection of physical effects, physicalmechanism and geometric/material characteristics of a product.

Fig. 6 is an example of a SDC. This catalogue provide severalkinds of knowledge concerning ‘‘Web server’’, ‘‘Electronic medicalchart’’, and ‘‘Refrigerator,’’ that makes a function ‘‘store something(materials, energy, or information)’’ become manifest. By referringseveral kinds of FEK in SDC, designers can select appropriate

ervice design catalogue).

Developme nt of a fun ction al stru ctu re

Translation of fun ction al type

Generation of desig n sol ution using SDC

The developed system provides FEK in a for m of a catalogue (SD C)

Step 1)

Step 2)

Step 3)

Fig. 7. Procedure to design a service using the developed system.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318314

function carriers or acquire new creative ideas to develop designsolutions.

4. Implementation of the knowledge-based PSS design supportsystem

4.1. Implementation of the design support system

On the basis of the proposed method reported in Section 3, aprototype of knowledge-based PSS design support system isdeveloped in this study. Here, the method proposed in Section 3was implemented as a plugin of the existing Service Explorer,which is a CAD system to design service reported in Section 2.3.

This system consists of three modules: (1) Design workspace,(2) Design knowledge base, and (3) service design catalogueviewer. The design workspace is to support service/PSS designactivities, i.e., operation and integration of design elements such asfunctions and entities. This module has been already implementedas a main function of Service Explorer Xi, which is the latest versionof Service Explorer. The second and third modules, designknowledge base and service design catalogue viewer, were newlydeveloped in this research. The design knowledge base enablesdesigners to edit and accumulate FEK in SDCs. The service designcatalogue viewer visually provides a SDC to designers. In this study,these modules are implemented using an Eclipse Rich ClientPlatform [20].

One of the virtues of the developed system is that designers caneasily increase the amount of knowledge through the knowledgeeditor. Furthermore, the knowledge is stored in the unified formshown in Table 2. This enables to share the knowledge amongmultiple designers in one system. This means that the developedsystem can be a platform of knowledge in service design.

4.2. Procedure to design a service using the proposed method

Fig. 7 illustrates the procedure to design a service with theproposed method.

In the first step (Step 1), designers develop a hierarchicalfunctional structure to fulfill customer needs through the functiondecomposition, i.e., development of the view model mentioned inSection 2.2.1. Then, in Step 2, designers translate the representa-tion of the most concrete functions in the hierarchical structure,which are going to be embodied, from ‘‘verb–noun’’ to ‘‘input–output’’ functions. Finally, in Step 3, the developed systemexplorers FEK from the knowledge base and provides them to

Fig. 8. Function model desig

designers in the form of SDCs. Here, FEK was explored based on thesimilarity between functions in the work space and knowledgebase. A SDC provides several kinds of FEK that can embody servicefunctions. Designers then select appropriate function carriers fromthe provided FEK. The selected function carrier can be a part of newdesign solution.

5. Application

The developed system were applied to a design of an actualservice: an accommodation service in Japan. This applied case isnot a PSS case but has an aspect of the integrated provision ofproducts and services, since it is obvious that both physical product(product share) and human activity (service share) are needed forservice offering.

As a preparation of the application, first of all, a designknowledge base, in which a piece of knowledge is described in theform of FEK, was constructed. The FEK was obtained and acquiredfrom a lot of service/PSS cases. In this application, designersacquire a variety of FEK mainly from the service/PSS case surveyresults, since the FEK acquisition is not automated in the currentsystem. The acquired FEK was inputted to the design supportsystem through the knowledge editor developed in this study. As aresult, a large amount of FEK was accumulated in the knowledgebase.

In this application, designers conducted an improvementdesign of this service by using the developed system includingthe constructed knowledge base. Finally, some design solutionswere generated.

5.1. Development of a functional structure (Step 1)

We collected questionnaire data that includes much informa-tion on customers’ voices. From them several kinds of customer

ned in the application.

Regula te

Regul ate

Tra nsmit

Regula te

F5

F6

F7

F8F4

Import

Customer data

F2F1

Store

F3

Material Informati onEnergy

Legend

Import Store

Info. of competitors

DivideDirty room

Trash

Clean room

Visual informati on

Ambient sound

Light volume

Landscape

Air temperature

Fig. 9. Result of translation of functional type.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318 315

needs to the service, such as ‘‘comfortable environment,’’‘‘attentiveness of staffs,’’ and ‘‘memorable dinner,’’ were extracted.In this application, the customer need ‘‘comfortable environment’’was focused on, since it was regarded as the most important one.

Service content, namely what is offered to customers, was thendesigned using the service function model to realize ‘‘comfortableenvironment’’ in the hotel. Fig. 8 shows the designed functionmodel. Two functions such as ‘‘Provide rooms that meet customers’preferences’’ and ‘‘Provide comfortable hotel life’’ were consideredas root functions to realize ‘‘comfortable environment.’’ These twofunctions were themselves decomposed into several sub-func-tions. Consequently, eight functions (F1–F8 in Fig. 8) wereidentified.

5.2. Translation of functional type (Step 2)

The sub-functions F1–F8 in Fig. 8 were described with the verb–noun approach. These functions were then translated into theinput–output functions. Here, the service function vocabulary listwas used to normalize lexical expression of the input–outputfunctions. The results are depicted in Fig. 9. For example, a

Fig. 10. A SDC for a function

verb–noun-type function ‘‘collect customer data’’ could betranslated into an input–output-type function ‘‘import informa-tion (customer data).’’

This translation was aimed at unifying the function represen-tation form, since the unified form makes it easy to search and findthe desired knowledge from the constructed knowledge base.

5.3. Generation of design solutions using SDC (Step 3)

In this step, FEK was explored from the knowledge base andprovided to the designer in the form of SDCs. Here, the FEK wasexplored based on the similarity between functions in work spaceand knowledge base. A SDC provides several kinds of FEK that canembody service functions.

Fig. 10 shows an example of a SDC that was presented to thedesigner in this application. As shown in Fig. 10, this cataloguecontains a variety of function carriers to realize a function ‘‘importinformation.’’

For each lower sub-functions in Fig. 9 (i.e., F1–F8), SDCs wereprovided by the developed system. From the provided SDCs,designers selected appropriate function carriers. Afterwards, the

‘‘import information’’.

Fig. 11. An example to generate a new design solution in this application.

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318316

designers evaluated them from the viewpoints of customer needsand monetary costs. The evaluation was done through discussionsamong designers. New design solutions to improve the hotelservice were then generated.

Fig. 11 shows an example to generate a new design solution.This is an example where a function ‘‘store information’’ (i.e., F2in Fig. 9) was focused on. The right part of Fig. 11 shows a SDCthat was provided for the function. In this SDC, a variety ofFEK to ‘‘store something’’ was listed. Designers selected‘‘Electronic medical chart’’ as a new function carrier; and thena new design solution was generated. The detailed description ofthis new design solution is shown in the following: DesignSolution (1). In the following, two design solutions that weregenerated by designers in this application are introduced asexamples.

5.3.1. Design Solution (1): ‘‘electronic chart’’ to manage customer

information

The hotel needs to collect and manage customer data (see F1and F2 in Fig. 8) to provide rooms that meet customers’preferences. Focusing on this, the designers proposed to introducea customer data management system applying an idea of‘‘electronic chart.’’ This idea was generated by referring knowledgeconcerning an electronic medical chart, which is often used tomanage patients’ information in medical services.

This design solution will be helpful to manage large amount ofcustomer data effectively.

5.3.2. Design Solution (2): ‘‘live sound’’ BGM (back-ground music)

To make a comfortable environment for customers, the hotelplays music at the lobby and restaurant. Normally, this kind ofBGM (back-ground music) is played by an audio system withspeakers, i.e., physical products. However, in this application, thedesigners found that such a set of products is not the only way toplay BGM. In particular, a new idea of ‘‘Live sound’’ BGM thatmeans BGM played by human (a pianist, violinist, and so on) wasgenerated.

The hotel can provide a special atmosphere by introducing thisdesign solution at the lobby or restaurant, although the realizationcosts of this must be high.

6. Discussion

6.1. Virtues of the proposed method and developed system

6.1.1. Effectiveness of knowledge-based design support

In this application four designers (designer A–D) were involvedin. We conducted interviews to each designer after they conductedthe improvement design using the developed system. Theirevaluations for the developed knowledge-based design supportsystem are as follows.

� SDCs provided by the design support system were very useful todesign a new service, since the system offered us a variety ofknowledge, e.g., knowledge regarding medical service, IT service,restaurant service and so on. This enabled me to create ideasfrom a broader perspective in service design (from designer A).� The system enabled us to generate new ideas that we could not

find in my brain (from designers A, C, and D).� SDCs offered several kinds of FEK. It helped us come up with a lot

of design alternatives. It is expected that the quality of designsolutions can be enhanced by using a lot of design alternatives asmaterials to discuss final design solutions (from designer B).� The more FEK the knowledge base has, the more effective its

design support is (from designers A and B).

From these evaluations, it was confirmed that the developedsystem realized an effective design support where the designobject was the integrated provision of products and services.

6.1.2. Developing design solutions considering both product and

service

In PSS context, for the purpose of offering flexible and high value-added solutions to customers, it is important for designers to have away of thinking that ‘‘both products and services are means to offervalues for customers.’’ Namely, designers should not stick to onlyproduct view or service view; but a holistic view is required.

In this research, both products and services are regarded asmeans of value offerings. The developed system provides productand service knowledge at the same time to designers. This leadsdesigners to have a holistic view when they create solutions forcustomers, and enables them to develop design solutionsconsidering both product and service views. In fact, the designsolutions (2) reported in Section 5.3 were generated by consideringthe substitution between a product and service, i.e., from a product(an audio system) to service (live music).

6.1.3. From ‘‘computer-aided-drawing’’ to ‘‘computer-aided-design’’

In Service Engineering, a computer-based service designsupport system called Service Explorer has been developed. Ithas been applied to actual cases (e.g., [8,9,12,21]) and regarded as auseful tool to describe a service/PSS structure. However, it issometimes pointed out that Service Explorer is not a computer-aided-‘‘design’’ but just a computer-aided-‘‘drawing’’ tool, since itdoes not have enough intelligent functions (e.g., providingknowledge) to support designers.

This research, which aims at developing a knowledge-baseddesign support system, is the first step to develop a computer-aided-‘‘design’’ system for a service/PSS that realize moreintelligent supports in service/PSS design activities. Meanwhile,the developed system can provide knowledge only in the functionembodiment phase. However, to develop more useful computer-aided-‘‘design’’ tool, which intellectually support designers in a

F. Akasaka et al. / Computers in Industry 63 (2012) 309–318 317

whole service design process, macro rules of the CAD systemshould be clarified. Here, the macro rules define, e.g., knowledgeshould be provided in service design, and specific design phase thatis appropriate to provide such knowledge. To clarify such macrorules, future researches will include the classification of servicedesign knowledge and the analysis of service design process, e.g.,by the design experiment method [22].

6.2. Remaining issues and future challenges

6.2.1. Need to support the evaluation phase

As mentioned in Section 5.3, designers could generate newdesign solutions by using the developed system. However, thedeveloped system does not support to ‘‘evaluate’’ the generatedsolutions. Actually, in the application, designers evaluate thegenerated solutions whether they realize the higher fulfillment ofcustomer needs or not through discussions. Therefore, a methodto evaluate the generated solutions must be needed. In themethod, design solutions should be evaluated with multiplecriteria such as potential for customer needs fulfillment andmonetary cost.

6.2.2. Need to support the configuration phase

The developed system provides a SDC that includes severalkinds of function carriers to realize a function. To fulfill the overallfunction, it is then necessary to elaborate overall solutions from thecombination of function carriers, namely configuration of functioncarriers. In the configuration phase, designers should discuss howto combine product and service shares to maximize the customersatisfaction or to minimize the costs. However, the developedsystem does not support the configuration phase. Therefore, amethod to support the configuration phase should be consideredand introduced.

6.2.3. Decrease in burdens on acquisition of an immense amount of

knowledge

The amount of FEK is the key determinant in the effectiveness ofdesign support using the developed system. As reported in Section4, the design knowledge base including a knowledge editor isimplemented in this research. Designers acquire knowledge from,e.g., books, news, or Web, and translate it into FEK using theknowledge editor; then the knowledge is accumulated in theknowledge base. This process put a burden on designers in the caseof the amount of knowledge is immense.

To solve this problem, one of the authors of this article isdeveloping a system to acquire knowledge automatically fromWeb resources [23]. This system automatically acquires pressrelease articles from the Web and extracts specific designknowledge from them. This system helps designers to acquirean immense amount of knowledge and construct a large-scaleknowledge base. However, knowledge acquired from Webresources includes not only very fruitful information but also alot of fruitless information. It will cause a decrease in reliability andreusability of knowledge. Therefore, future researches will includethe integration of the developed knowledge base and thisautomatic knowledge acquisition system considering the optimalbalance between the amount and the reliability of knowledge.

6.2.4. Application to an actual PSS case

As reported in Section 5, the developed system was applied to adesign of an accommodation service. In this application, the designwas conducted from the viewpoint of the integrated provision ofproducts and services; this way of design thinking is very close tothe PSS concept. However, actually, the case is not a PSS case.Therefore, the developed system must be applied to a design of anactual PSS cases in the near future.

7. Conclusion

In this article, we propose a method for knowledge-based PSSdesign support. The basis of the proposed method is service designmethodology discussed in Service Engineering. Furthermore, aprototype of a knowledge-based PSS design support system isdeveloped on the basis of the proposed method. This systemsupports the acquisition of new PSS design solutions byintegrating knowledge accumulated in a knowledge base. Theapplication result showed that the developed system was usefulto support a design of the integrated provision of products andservices.

Acknowledgement

This research was partially supported by the JSPS (JapaneseSociety for the Promotion of Science) Research Fellowship forYoung Scientists.

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F. Akasaka et al. / Computers in Industry 63 (2012) 309–318318

Mr. Fumiya Akasaka has been a Ph.D. student in

Department of System Design, Tokyo Metropolitan

University, Japan. He has been also a Research Fellow of

the Japan Society for the Promotion of Science (DC1). He

received his B.S. in 2009 and M.S. in 2011 at Department

of System Design, Tokyo Metropolitan University,

Japan. His major research areas are Design Engineering,

Service Engineering (SE), and Product Service Systems

(PSS) Design. In recent years, his research interests are

in knowledge-based design support and collaborative

design tool for PSS design.

Mr. Yutaro Nemoto is a M.S. student in Department of

System Design, Tokyo Metropolitan University. His

research topics include Service Engineering, Product

Service System (PSS), Design Methodology, Design

Knowledge Management, and Intelligent Design Sup-

port System. He received his B.S. from Department of

System Design, Tokyo Metropolitan University in 2011.

Dr. Koji Kimita has been a fellowship researcher in

Department of System Design, Tokyo Metropolitan

University, Japan since 2011. He received his B.S., an

M.S., and Ph.D. from the university in 2006, 2008, and

2011 respectively. His interests include design meth-

odology for Service, Service Quality, and Customer

Value.

Dr. Yoshiki Shimomura has been a Professor in the

Human Mechatronics Systems Course, Department of

System Design, Tokyo Metropolitan University, since

2005. Prior to this appointment, he was an Associate

Professor in Research into Artifacts, Center for

Engineering, the University of Tokyo. He received his

Ph.D. in precision machinery engineering from the

Graduate School of the University of Tokyo in 1997.

Dr. Shimomura’s research interests include service

engineering, life-cycle engineering, design theory and

methodology, intelligent systems, reasoning mecha-

nism, and soft machines (self-maintenance machines

and cellular machines).