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Logic of EngineeringLogic of Engineering DDesigningesigning

Žiga TurkŽiga Turk

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ContentsContents

Short introduction to modelingShort introduction to modeling Reference modelsReference models

structure – function – behavior model Short introduction to logicShort introduction to logic Logic of the SFB modelLogic of the SFB model

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LiteratureLiterature

Books:Books: Eastman, C.M. (1999). Building Product

Models, CRC press, ISBN 0-8493-0259-5. Sowa, J.F. (2000). Knowledge

representation, Brooks/Cole, ISBN 0-534-94965-7.

Sowa, J.F. (1984). Conceptual Structures: Information Processing in Mind and Machine, Addison Wesley, ISBN

Raphael, Smith: Computer Aided Engineering.

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DefinitionsDefinitions

model:model: reproduction of something [m-w] perfect: deserving to be imitating

modelling: a process during modelling: a process during which models are createdwhich models are created

modeller: a person who is modeller: a person who is modellingmodelling

examples:examples: model railroads, model buildings, finite

elements models

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sEvolution of modelling Evolution of modelling in constructionin construction construction is about big 3D objectsconstruction is about big 3D objects communication is essentialcommunication is essential communication through drawingscommunication through drawings contributors:contributors:

Brunelleschi, 15th century, scaled drawings Monge, 18th century, projections

exchange of drawings: vital exchange of drawings: vital information “technology”!information “technology”!

drawing is also a modeldrawing is also a model

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SYMBOL

OBJECT

CONCEPT

B-E-A-M

Philosophical Philosophical foundations of foundations of modellingmodelling how we understand how we understand

the world around the world around usus

the meaning the meaning triangletriangle

AristotleAristotle things words experiences in the

psyche Ogden and Ogden and

Richards:Richards: object symbol concept

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sMeaning triangle:Meaning triangle:ObjectObject The object is any The object is any

entity from some entity from some real or imagined real or imagined world about which world about which an idea is held. for an idea is held. for example the beam example the beam in the Nada Ward in the Nada Ward Museum of Museum of Modern Art in Modern Art in Kobe damaged by Kobe damaged by an earthquakean earthquake

SYMBOL

OBJECT

CONCEPT

B-E-A-M

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sMeaning triangle:Meaning triangle:SymbolSymbol The symbol is an The symbol is an

auditory, visual, auditory, visual, or other form of or other form of utterance that is utterance that is taken to stand taken to stand for the object for the object when when communicated communicated as part of a as part of a languagelanguage

SYMBOL

OBJECT

CONCEPT

B-E-A-M

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sMeaning triangle:Meaning triangle:ConceptConcept The concept is The concept is

the idea or the idea or thought of the thought of the object as held in object as held in the mind of a the mind of a person, for person, for example a example a structural structural concept of a concept of a beam. as beam. as illustrated. illustrated.

SYMBOL

OBJECT

CONCEPT

B-E-A-M

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Mind and machineMind and machine It has been suggested that intelligent It has been suggested that intelligent

systems achieve their intelligence by systems achieve their intelligence by manipulating symbols of real world manipulating symbols of real world objects. Humans do it by manipulating objects. Humans do it by manipulating "experiences in the psyche", concepts "experiences in the psyche", concepts or "mind models". Computers could or "mind models". Computers could manipulate symbolic representations of manipulate symbolic representations of the models. Therefore, computers the models. Therefore, computers could achieve intelligence, just as could achieve intelligence, just as humans do, if only the models and the humans do, if only the models and the manipulation rules could be complex manipulation rules could be complex enough.humans are intelligent, enough.humans are intelligent, because they and computers handle because they and computers handle symbols.symbols.

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Mental modelsMental models when we think, we create a model of the when we think, we create a model of the

messy real world situationmessy real world situation

we manipulate the modelwe manipulate the model we solve a problemwe solve a problem models can be represented as semantic models can be represented as semantic

networksnetworks

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Semantic networksSemantic networks

nodes: conceptsnodes: concepts arches: relations arches: relations

between between conceptsconcepts

example:example:

PS: similar toPS: similar tohypertexthypertextnetworks!networks!

wall

doorwindow

openingwhite

has has

is-an is

strength

reduces

is-an

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Moving semantic Moving semantic networks into a networks into a computercomputer repetition, reuse, frames or similarrepetition, reuse, frames or similar computer program should be good computer program should be good

at helping in several situationsat helping in several situations instances - uniqueinstances - unique

1:1 mapping to real world problem “this wall in this room”

concepts - genericconcepts - generic one generic concept corresponds to several

real world items “walls in general”

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Reference modelsReference models

reference modelreference model impose certain perspective on the

world to be modelled define how to model how to decompose the model

GARMGARM RATASRATAS form, function, behaviourform, function, behaviour

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GARMGARM General AEC General AEC

Reference ModelReference Model Describes a Describes a

“Product “Product Definition Unit” Definition Unit” (PDU)(PDU)

PDU has PDU has characteristics characteristics that refer to that refer to aspect of the aspect of the product. Aspects:product. Aspects:

strength, cost, safety, durability...

PDU has “stage PDU has “stage discriminator” to discriminator” to include life include life cycle:cycle:

as required, designed, planned, built, used altered, demolished

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GARM: Functional GARM: Functional Units and Technical Units and Technical SolutionsSolutions defined and required characteristicsdefined and required characteristics one functional unit, several technical solutionsone functional unit, several technical solutions each technical solution, several functional unitseach technical solution, several functional units

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GARM: FU/TS ExampleGARM: FU/TS Example

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sGARM: Building GARM: Building exampleexample

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Form, function, Form, function, behaviour (fit, working behaviour (fit, working principle)principle) popular with design sciencespopular with design sciences

form: the structure of the design as captured by the parts hierarchy.

function: the intended behaviour of the artifact that is designed as might be found in a functional classification of parts.

behaviour: the causal relationships between different parts of the artifact.

fit: how do the parts of the design fit together?

working principle hydraulic, electro-mechanic etc.

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sForm, function, Form, function, behaviour modelbehaviour model products or their parts have:products or their parts have:

form or structure function ... the purpose they server behaviour ... how they react to

environment for example a wall:for example a wall:

form: x,y,z,w,d,h function: load bearing,

heat insulating, sound insulating behaviour … what happens

w

h

d

x,y,z

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InferenceInference

deductiondeduction abductionabduction inductioninduction

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Types of inferenceTypes of inference

type of type of inferenceinference

givengiven givengiven inferredinferred

deduction cause rule effect

force theory of elasticity

deflection

abduction effect rule cause

deflection theory of elasticity

force

induction cause effect rule

force deflection theory of elasticity

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… … and inference …and inference …

cause cause = = environmentenvironment structurestructure = structure (cause?) = structure (cause?) functionfunction = = effecteffect behaviourbehaviour = = effecteffect working principleworking principle = = rulerule fit ???fit ???

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FormulationFormulation

formulation

F

Brequired

F = FunctionB = BehaviorS = Structure (+environment)

transformation

comparison

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Sas-designed

Brequired

F

formulation

synthesis

Formulation + synthesisFormulation + synthesis

F = FunctionB = BehaviorS = Structure (+environment)

transformation

comparison

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Sas-designed

Brequired

F

formulation

synthesis

Formulation, synthesis, Formulation, synthesis, analysis, evaluationanalysis, evaluation

Bpredicted

evaluation

analysis

F = FunctionB = BehaviorS = Structure (+environment)

transformation

comparison

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Sas-designed

Brequired

F

formulation

synthesis

… … construction …construction …

Bpredicted

evaluation

analysis

construction

F = FunctionB = BehaviorS = Structure (+environment)

transformation

comparison

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Sas-designed

Brequired

F

formulation

synthesis

… … measuring, monitoringmeasuring, monitoring

Bpredicted

evaluation

analysis

Sas-built

Bmeasured

prediction

monitoring

induction of new models

construction

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Engineering tasksEngineering tasks

analysis = deductionanalysis = deduction structure + cause + rules effect structure + cause + working principle function

simulation = deductionsimulation = deduction structure + cause + rules effect structure + cause + working principle behaviour

diagnosis = abductiondiagnosis = abduction structure + effect + rules cause structure + behaviour + working principle cause

synthesis = abductionsynthesis = abduction effect + rule structure function + behaviour + working principle structure

interpretation = inductioninterpretation = induction cause + effect = rule cause + structure + behaviour = working principle

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Tasks by NewellTasks by Newell

well definedwell defined closed worldsclosed worlds explicit goalsexplicit goals described by described by

algorithmsalgorithms

ideal situationideal situation

ill definedill defined open worldopen world partially defined partially defined

goalsgoals procedures to procedures to

obtain solutions obtain solutions not knownnot known

reality of reality of engineering tasksengineering tasks