Functional Models

8/17/2019 Functional Models

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A comparative case study of functional models to support systemarchitecture design

Sonia Ben Hamida abc , Antoine Grandou b, Marija Jankovic b, laudia !ckert d, Alain Huet a , Jean"Boc#uet b

a AIRBUS Defence & Space, Les Mureaux, FrancebEcole Centrale Paris, C atena!"Malabr!, Francec Institut # e Rec erc e $ec nolo%i ue S!ste'(, Palaiseau, France# )pen Uni*ersit!, Milton +e!nes, En%lan#


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• Why modelling functions matters?

onte$t

• Improving understanding and knowledge capture

Motivation

• Case study, Approaches selection & Evaluation criteria

Methodology

• Advantages and limits for each approach

%esults

• Complementary use of modelling methods

&iscussion and onclusion


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onte$t

System architecture' “(1) the arrangement of functional ele'ents ; (2) thfrom functional elements to p !sical co'ponents ; (3) the specification of the

among interacting physical components” (Ulrich, 1995)= functional architecture = one facet of system architecture

(unctions' allow to translate needs into physical structures that will meet those needs!ut “ no clear and uniform definition of a function !oreo"er, it seems i'possiblefunction o#$ecti"ely” (Umeda et al , 1995)

(unction modelling' a formal way to define and model functions= framework for overall system description!ut more than )* different function modelling approaches (%rden et al , 2&&

am"iguity in functional description



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Motivation

#ain purposes of functional description (*omiyama, 2&13)+$epresent the purpose of the artefact

E%plain the behavior, structureCapture customer re#uirementsIllustrate the overvie+ of the system

ifficulties to use function modelling in industry environment'(ractice' ) e"er used it”, “ o added "alue”, “ ot practical” (*omiyama et al , 2&13)Identify the distance "etween the model and the systemIdentify if elements have "een missed*nderstand rationales



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%esearch design

Case study' esign of an intelligent refrigerator (-e.is et al, 2&13)Which new services to enhance customer satisfaction?

+election of the four modelling approaches'


Approach Selected because

(ro"lem definition process (*huillier et al , 2&1&) s applied by industry to compl

unction-!ehavior-+tate (/himomura et al , 199') s one of the only process ori

unctional representation to support ideageneration (0ha ra#ati et al , 2&&5)

takes into account e$isting soluti

Affordances (0ormier et al , 2&13) s user"centric


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Selected criteria

ndustry criteria %esearch criteria Su''ers, -./01

$efine operational scenario until elementaryoperation and function Scalability, -remature commitment, onstructio

+pecifies functional interface "etween elementaryfunctions onstruction

+pecifies "ehavior of elementary function Behavior

#ap Elementary function and flow on physical itemsand links onsistency

.erification capa"ilities /consistency checks0 onsistency

+imulate simple "ehavior Behavior

$eada"ility of models /easiness to review ,communicate and present to non-specialist0 .isibility

Ease of use1Ergonomics (le$ibility, loseness of mapping, !proneness



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%esults )/ -roblem definition process

+tep-"y-step systematic method

Completeness of the model?$ationale of the model


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unction' )description of "ehavior a"stracted "yhuman through recognition of the behavior forutili0ation 2

3hinking of functions and theirperformances at the same time

iscovering functions through a top-down4"ottom-up approach

(oor reada"ility and not functionalalternatives management

%esults 1/ (unction"Behavior"State approach


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%esults 2/ (unctional representation to support idea generation

unction' )description of the action or effectre#uired "y a design pro"lem, or that issupplied by a solution 2

+imilarities of the pro"lem to tackle withe%isting systems

ifficult with an increased num"er ofcomponents and interactions


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&iscussion


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onclusion

!uilding and using functional models is not straightfor+ard in stages

We have identified four approaches with regard to their applindustry

We discussed the merit and limits of each of them, and the com

use of these modelling methods



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%eferences

65 +himomura, #5 6oshioka, 75 3akeda, 65 *meda, 35 3omiyama, $epresentation of design o"8ect "ased on the functional evolution process model, 9ournal of #echanical esign5:;< /: >0 ;;:4;; 5(5 Cormier, A5 lewnik, @5 ewis, 3owards a ormaliBation of Affordance #odeling in the Early +tages of esign, in' A+#E ;

Functional Models

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