Functional Ontology of Artifacts

Riichiro Mizoguchi

The Institute of Scientific and Industrial ResearchOsaka University

http://www.ei.sanken.osaka-u.ac.jp/

Agenda Background

– Organization of Engineering Knowledge• Functional Ontology of artifacts• Functional structure description framework

and its deployment

Functional ontology– Function of artifacts– Function of Bio-organisms

Concluding Remarks– A unified ontology of function?

Ontology as a model of the reality

Used as building blocks of knowledge-intensive systems– Something deeper than metadata– It provides foundation on which a KB or an

application system is built

Ontology

KnowledgeBase

(Model)An explicit specification of a hidden conceptualization of the target domain

Layers of functional ontology and knowledge

Specific to an object.

Dependenton

designersviewpoint

Functionallayer

Attribute trees

Top level ontology(entity, process, time, etc.)

Functional model of the target artifact

Generic functiondecomposition tree

Ways of functionalachievement

Physical lawPrinciple

Part libraryFunctional ontology

Funda-mental

Generalknowledge

Conceptualization of function

Description of way of achievement reference

Viewpoint-specificstructuringcombination

Functiondecomposition tree

Extended device ontologySpecialization from device-centered view

A functional concept ontology

Functions to information

Make informationexistent

情報をかくす

情報を生成する情報を変える

情報をためる

情報を増やす

情報を減らす

特殊化する

詳細化する概略化するSearch (I)

Transmit information

Add (I)

Obtain (I)Give (I)

Give (I)(2)

伝える +

Transmit (I)(2)

情報の媒体を変換する

Obtain (I) (2)

情報を変える +

一般化する

Base functions

Functions to force and motion

Function to force

Generate force

Change force

Distribute force

Change direction Convert (F)

Change magnitude

Function to motion

Give force Absorb force

Combine (F)

Transmit force運動を生成する 運動を

変える

運動の方向を変える

運動の種類を変える

運動を存在させる

運動を伝える

運動を非流動媒体間で伝える

運動を分ける

運動の大きさを変える

運動をなくす

運動を合わせる

運動を流動媒体間で流す

Entity functions

Change

Separate

Increase Decrease

Make entity existent

合わせるPass trough

ためる

Convert Pass tr.(2)

Pass tr.(3)

Change (2) Generate 結合力をなくす

生成する

Detach 分ける +分解する +

Take out 分ける ++

Energy function

Shift (E)

Change (E)

Separate (E)

Increase magnitude (E)

Decreasemagnitude (E)

Make energyexistentConsume (E)

Combine (E) Pass trough (E)

Store (E)

Convert (E) Pass tr.(E)(2)

Pass tr.(E)(3)Give (E)(2)

Add (E)Give (E)(3)

Take (E)Give (E)

Release (E)

Transmit (E)

Remove (E)

Take aw y (E)(2)

Transmit (E)(2)

Convert (E)(2)

Function types

make holdmaintain

Function typesis-a

mandatory contribution

optional contribution

enable

preventprovide

drive

allow

Meta-functions

improve enhance

contribute

control

is-a

compensate

Meta-functions

Function achievement way

全体機能

部分機能１ 部分機能２ 部分機能３

方式

方法

原理・理論

現象 構造

部品

機能分解

Subfunction1

Functional Decomposition

Subfunction3Subfunction2

Function

WayComponent

Structure

Phenomena

Theory

Method

Functional modeling framework

Ways for

(e) Functionalconceptontology

(c) The generic ways of function achievement

way

is-a

function

(a)Functiondecomposition tree

(b) General function decomposition tree

way Ways for

is-a

“is-achieved-by” relations among functions with ways

OR

OR

ANDAND

AND

(f) Extended device ontology

(d) Attribute trees of ways (specific to

each viewpoint)

Instances of generic functions

“is-a” relations between generic functions

“is-a” relations between generic ways of functionachievement based on their principles

Organizingstep

Modelingstep

AlternativewaysGuide-

lines

Abstractions of“what to achieve”

Abstractions of“how to achieve”

Deployment into three manufacturing companies

Production Systems Engineering Division of Sumitomo Electric Industries Ltd., Japan

History– Started in May, 2001.– Number of functional models: 103 machines as of

Summer in 2003– Number of people using: 50– Used in daily work in 2 factories– SOFAST users’ group: Currently, 13 companies have

joined – OntoGear by Just System Corp.

How functions of artifacts andbio-organisms are different

Issues What Function is

Where Function exists

– Essential Function and accidental Function

How Function is different from behavior

Definitions Artifact Function is defined as:

– the teleological interpretation of behavior under a goal

– the Role played by behavior specified in a context

Biological Function is defined as:– the disposition of a certain entity reliably to act in

such a way as to achieve a goal (Barry Smith)

A framework for capturing function

Two kinds of Goals as a context– Goal-I: One includes ordinary goals which are possessed by the thing

as a purpose intended by the thing itself or an outsider.– Goal-NI: The other is nothing to do with “intention” but something

which is necessarily forced to have it from the system perspectives, that is, each component collaboratively contributes to the achievement of the consistent behavior of the total system.

Agent Anotheragent

Anotheragent

Input Output

Goal-IIntentionpurposeGoal-NI

A system as a whole

a component

A heat exchanger

inletmedium

p2p1

p3 p4

outlet medium

ports

energyflow

inletenergy(heat)

outletenergy(heat)

inletmedium

p2p1

p3 p4

outlet medium

ports

energyflow

inletenergy(heat)

outletenergy(heat)

Warmer liquid(fluid)

Cooler liquid(fluid)

A Functional Upper Ontology

Devicefunction

Property function

(normal)Function

Way function

Inter-devicefunction

Environmentalfunction

Effect function.

State-operationalfunction

Process-operationalfunction

Function

System boundaryfunction

Meta function

Characteristicfunction

Dispositionfunction

Physical environmentalfunction

EnvironmentalInterpretive function

User action Enabling function

Requirement function

Genuineeffect function.

Devicefunction

Property function

(normal)Function

Way function

Inter-devicefunction

Environmentalfunction

Effect function.

State-operationalfunction

Process-operationalfunction

Function

System boundaryfunction

Meta function

Characteristicfunction

Dispositionfunction

Physical environmentalfunction

EnvironmentalInterpretive function

User action Enabling function

Requirement function

Genuineeffect function.

A rod pushes up a cam

A fan cools down a man

To weld

To separateTo enable

A clock tells time

A roomenablesa meeting

Life-cyclic view of functionsRequirements(in terms of function)

Particular thing with a structure and materials

Behavior

Function used by the user/the other

Functions exist outside an artifact

Some essential properties enabling the function (Function as a disposition)

How behavior is different from function?

Exhibition process of a function

My current understanding

Function-I (Disposition)Supported by materials and structure

Requirement (= use)

Behavior

Essential function-E Accidental function=E

Determined_by

Function = Function-I (supported by materials and structure) + Function-E (what behavior delivers)

Function-E_1

= What behavior deliversAgent (Identity)

Supported_by

Context_1Purpose/goal

Context_2Purpose/goal

Function-E_2

= What behavior delivers

Concluding remarks Functional ontology

– Function of artifacts has been established and deployed into the industries

– The definition of Biological function is very different from that of Artifact function

– An upper level functional ontology helps organize various definitions of function

– How can we come up with a unified model of function?

Thank you

Extended device ontologyMajor elements

– Device(plays an agent role)•It operates on the flowing thing(operand) to process it ． Black box assumption

– Conduit ＝ Semi-agent•Ideally, it can be considered that it changes only location of the flowing thing. E.g., pipe and shaft

– Operand (which virtually flows with an operand role)•What is virtually flowing between devices•It is processed by the device. The change of its state is interpreted as the behavior of the device.E.g., energy, fluid, motion&force, information

– Medium•It maintains the flowing thing to enable it “to flow”E.g., fluid and shaft

•It might flow, but not necessarily– Connection, Input/output

Device

Flowing stuff Conduit

Medium

Generic definition of function– Function is a teleological interpretation of a

behavior under a goal– Function = behavior + functional topping (FT)

•Our modeling language: FBRL [IJCAI 1995]•FTs: Focused attribute, focused ports, necessity

take give1

robremove

cool1

shiftFocus onsource

NoNeed Need

heat

radiator

heat1 press

heatpressure

heater pump

transport

give2

generate addzero

Energy function

pass trough

on a mediumtwo different mediumsis-a

recipient

convert

:e-def (and (has-energy-objects ?fd (?e0 ?e1 ?e2)) (has-medium ?fd ?m0 ?e0) (has-port ?fd (?p1 ?p3) (?p2 ?p4)... ):b-def (and (mp-relation ?e0 ?e1) (mp-relation ?e0 ?e2) (mp-relation ?m0 ?m1) (not (mp-relation ?m0 ?m2))

:f-def ((focus-on-ports ?fd ?p3 ?p4))

:f-def ((focus-on-ports ?fd ?p1 ?p2))

behavioral condition

functional topping of“to take”

functional topping of“to give”

inletmedium

p2p1

p3 p4

outlet medium

ports

energyflow

inletenergy(heat)

outletenergy(heat)

“focus on the source-medium of the transfer"

“focus on the medium receiving the energy”

Behavioral model