DIGITAL

COMMUNICATION

TECHNOLOGY

CONNECTING

DESIGN

ENGINEERING

AND

MANUFACTURING

MARCIO

ZUKIN

Dept.

of

Industrial

Engineering

PUC-Rio

Rio

de

Janeiro

BRAZIL

e-mail

marzukin@rdc.puc-rio.br

HUGO

FUKS

e-mail

hugo@inf.puc-rio.br

PAULO

R.

T.

DALCOL

Dept.

of

Industrial

Engineering

PUC-Rio

Rio

de

Janeiro

BRAZIL

e-mail

prtd@rdc.puc-rio.br

PUC-RioInf

MCC

Abstract

Companies

increasingly

need

to

reduce

lead

times

in

product

development

as

a

way

to

get

products

onto

the

market

faster

and

more

efficiently

Digital

communication

integrating

design

engineering

and

manufacturing

can

greatly

improve

the

product

development

process

through

concurrent

engineering

and

overlapping

activities

This

paper

presents

a

case

study

on

how

digital

communication

can

overcome

temporal

and

geographical

barriers

in

the

exchange

of

information

enhancing

a

collaborative

and

cooperative

environment

The

project

studied

was

a

vacuum

cleaner

developed

in

Electrolux-Italy

in

which

the

first

author

of

the

paper

participated

as

Senior

Product

Designer

In

this

paper

the

authors

describe

and

analyze

the

process

and

then

elaborate

a

scenario

that

contemplates

networks

for

digital

communication

and

a

technology

infra-structure

for

the

process

highlighted

Resumo

As

empresas

necessitam

crescentemente

reduzir

o

lead

time

no

desenvolvimento

de

produtos

de

modo

a

lan?ar

produtos

no

mercado

mais

rapidamente

e

eficientemente

A

comunica

o

digital

integrando

o

Design

a

Engenharia

e

a

Manufatura

pode

representar

uma

grande

melhoria

no

processo

de

desenvolvimento

de

produtos

por

meio

de

engenharia

simult?nea

e

atividades

sobrepostas

Esse

artigo

apresenta

um

estudo

de

caso

de

como

a

comunica

o

digital

pode

superar

barreiras

temporais

e

geogr?ficas

no

interc?mbio

de

informa

es

criando

um

ambiente

colaborativo

e

cooperativo

O

projeto

estudado

foi

um

aspirador

de

p

desenvolvido

Electrolux

It?lia

no

qual

o

primeiro

autor

do

artigo

participou

como

designer

de

produto

s?nior

Nesse

artigo

os

autores

descrevem

a

analizam

o

processo

e

ent?o

elaboram

um

cen?rio

que

contempla

redes

para

um

sistema

de

comunica

o

digital

e

uma

infra-estrutura

de

tecnologia

para

o

processo

em

quest?o

Palavras-chave

Comunica

o

Digital

Engenharia

Simult?nea

Desenho

Industrial

Engenharia

Manufatura

Sponsored

by

the

Brazilian

Ministry

of

Education

-LRB-

CAPES

grant

social

demand

-RRB-

and

the

Brazilian

National

Research

Council

-LRB-

CNPq

grants

300 608/90

and

302 206/86

-RRB-

INTRODUCTION

This

paper

addresses

the

analysis

and

construction

of

a

digital

working

space

focusing

on

the

communication

process

The

analysis

concentrates

on

the

relationship

between

the

functions

of

design

engineering

and

manufacturing

in

the

production

of

high

quality

products

developed

in

very

short

lead

times

Digital

communication

is

a

computer-based

support

for

concurrent

engineering

that

can

overcome

temporal

and

geographical

barriers

in

the

exchange

of

information

Digital

communication

can

link

large

groups

of

physically

separated

people

enhancing

a

collaborative

and

cooperative

environment

for

the

design

engineering

and

manufacturing

of

a

product

In

this

paper

digital

communication

is

designed

to

be

applied

at

the

final

stages

of

a

product

development

process

that

started

at

the

strategic

planning

stage

First

the

product

development

process

was

studied

in

its

general

aspects

Then

a

specific

case

was

chosen

that

presented

a

product

with

a

complex

and

high

quality

design

The

process

selected

was

a

project

developed

in

Electrolux-Italy

in

which

the

first

author

of

the

paper

participated

as

Senior

Product

Designer

Later

the

product

development

process

chosen

was

described

and

analyzed

The

research

then

focused

on

application

software

that

could

be

used

for

digital

communication

Finally

we

elaborated

scenarios

that

contemplated

networks

for

the

digital

communication

process

and

a

technology

infra-structure

for

the

process

highlighted

These

scenarios

were

analyzed

in

terms

of

cost

software

packages

training

and

process

deployment

This

digital

communication

system

was

designed

specifically

for

the

organizational

culture

and

product

development

approach

of

the

Electrolux

Corporation

in

Milan

Italy

However

since

product

development

has

a

certain

degree

of

generality

we

believe

it

is

possible

to

apply

this

particular

system

to

many

other

cases

The

recommended

solution

for

the

Electrolux

case

was

to

purchase

software

outside

the

company

and

not

develop

an

in-house

integration

system

as

happened

in

Toyota

for

its

CAD/CAM

system

-LRB-

Ohara

-RRB-

The

solution

to

purchase

software

off-the-shelf

was

highly

enforced

due

to

reduced

costs

and

good

quality

service

Once

software

has

been

purchased

outside

the

company

the

in-house

Systems

Engineer

should

be

responsible

for

integrating

it

to

the

company?s

culture

and

routines

The

research

delineated

in

this

paper

treated

the

product

development

process

in

Electrolux-Italy

as

an

object

of

study

aiming

at

the

creation

of

digital

communication

solutions

for

improvement

and

new

functionality

in

this

process

The

result

of

this

research

was

not

proposed

for

implementation

and

it

will

likely

need

more

testing

and

refinement

COMMUNICATION

AND

INTEGRATION

SYSTEMS

The

digital

mechanisms

that

integrate

design

with

engineering

and

manufacturing

must

adapt

to

the

design

activity

and

its

complexity

matching

the

product?s

need

of

range

and

flexibility

quality

and

so

on

The

most

highly

integrated

digital

systems

are

warranted

only

when

there

are

high

design

task

coordination

requirements

-LRB-

Liker

et

al.

-RRB-

Low

design

task

coordination

requirements

are

attributed

to

projects

where

the

information

processing

requirements

are

low

and

the

product

designed

is

a

minor

variant

of

an

existing

product

consisting

of

few

components

Thus

it

is

possible

to

delegate

the

design

of

the

components

to

different

designers

with

low

communication

necessity

In

contrast

high

design

task

coordination

requirements

refer

to

projects

that

require

high

information

processing

have

complex

shapes

their

tasks

uncertainty

is

high

and

design

decisions

are

interdependent

In

a

design

activity

with

low

design

task

coordination

requirements

it

is

possible

to

use

a

courier

service

to

mail

blueprints

or

data

files

on

tape

or

disk

When

there

are

medium

design

task

coordination

requirements

it

is

possible

to

use

a

computer

modem

and

a

telephone

line

to

transmit

files

that

require

translation

or

to

transmit

files

between

compatible

systems

When

there

are

high

design

task

coordination

requirements

it

is

possible

to

use

a

computer

modem

telephone

line

and

a

network

for

asynchronous

use

of

a

common

database

It

is

also

possible

to

work

concurrently

on

the

same

database

thus

communicating

in

real

time

As

well

as

the

digital

mechanisms

the

organizational

integration

mechanisms

must

fit

the

design

activity

and

its

complexity

Similarly

design

tasks

with

high

design

task

coordination

requirements

will

benefit

from

higher

levels

of

integration

-LRB-

Liker

et

al.

-RRB-

The

organizational

integration

mechanisms

will

also

influence

the

requirements

of

digital

communication

In

a

design

activity

with

low

design

task

coordination

requirements

it

is

possible

to

use

design

rules

or

ad

hoc

communication

with

low

organizational

integration

Systems

based

on

design

rules

have

some

fixed

paths

of

reasoning

that

do

not

match

with

design

reasoning

When

there

are

medium

design

task

coordination

requirements

it

is

possible

to

use

cross-functional

teams

or

job

rotation

with

medium

organizational

integration

In

crossfunctional

teams

group

decision

making

may

be

difficult

there

is

a

limitation

on

the

team

member?s

knowledge

and

there

are

the

increasing

costs

of

maintaining

a

team

-LRB-

O?Grady

and

Young

-RRB-

These

difficulties

occur

especially

when

there

is

no

digital

communication

integrating

the

people

involved

in

different

geographic

locations

When

there

are

high

design

task

coordination

requirements

it

is

possible

to

use

colocation

or

combined

roles

and

organizational

structure

changes

for

horizontal

processes

with

high

organizational

integration

The

need

of

co-location

or

other

physical

change

in

the

organization

for

high

complexity

design

activity

diminishes

when

there

is

an

efficient

computer

network

in

function

In

the

case

of

the

product

development

process

at

Electrolux-Italy

there

was

high

design

task

coordination

requirements

This

paper

is

focused

only

on

the

digital

integration

and

communication

of

that

process

therefore

excluding

the

influence

of

the

complexity

of

the

design

activity

on

the

company?s

organization

In

the

next

section

we

give

a

description

of

one

specific

communication

process

THE

PRESENT

COMMUNICATION

PROCESS

An

ontology

of

the

collaborative

work

domain

was

built

in

terms

of

a

conceptual

framework

for

interpreting

the

domain

in

terms

of

recurrent

communication

and

transportation

actions

-LRB-

Denning

and

Dargan

-RRB-

First

a

communication

structure

-LRB-

Figure

-RRB-

was

elaborated

mapping

the

present

communication

process

and

trying

to

find

possibilities

for

improvement

and

new

functionality

through

digital

communication

In

the

case

to

be

described

the

engineering

management

outsourced

the

design

activity

to

Unitec-Milan

an

external

office

that

has

worked

for

Electrolux

in

since

its

foundation

Therefore

Unitec

had

an

easy

interaction

with

the

firm

organization

and

its

interlocutors

Electrolux

also

subcontracted

the

model

and

prototype

makers

the

materials

supplier

and

some

manufacturing

processes

specified

in

the

design

The

product

developed

was

to

be

sold

globally

After

Italy

the

first

countries

to

place

this

new

product

on

the

market

were

to

be

England

France

and

Australia

where

Electrolux

also

has

factories

Nevertheless

only

the

engineering

department

of

the

Italian

branch

of

Electrolux

participated

in

the

product

In

the

late

s

the

Swedish

corporation

Electrolux

acquired

the

Italian

company

Alfatec

which

was

the

leading

Italian

vacuum

cleaner

manufacturing

company

development

process

There

was

great

difficulty

in

coordinating

it

globally

mainly

because

of

problems

and

handicaps

in

the

conventional

modes

of

communication

The

product

to

be

developed

was

the

Global

New

Vacuum

Cleaner

that

deals

with

spills

and

floods

and

also

performs

carpet

shampooing

without

the

need

of

a

motorized

water

and

shampoo

pump

In

the

following

description

the

departments

were

collapsed

into

the

manager

person

of

each

function

In

this

case

the

richness

of

the

communication

is

in

the

interdepartmental

relationship

and

not

between

the

workers

of

the

same

department

AGENTS

RESPONSIBILITIES

The

mission

statement

of

each

function

was

also

the

criteria

for

the

evaluation

of

each

department

's

performance

All

the

departments

mission

statements

were

general

in

what

concerned

the

product?s

brief

that

was

defined

at

the

strategic

planning

stage

The

mission

statements

were

specific

in

the

following

terms

DES

Design

functionality

styling

manufacturability

of

the

product

designed

and

model

making

management

ENG

Engineering

development

of

technological

solutions

producibility

of

technical

parts

and

management

of

prototype

making

and

tool

design

MAN

Manufacturing

management

of

tool

making

development

of

the

facilities

and

the

processes

used

to

fabricate

and

assemble

the

product

designed

quality

control

and

dependability

PROCESS

INPUT

AND

OUTPUT

The

input

of

this

product

development

process

was

studied

in

terms

of

material

equipment

physical

communication

devices

shared

workspace

and

environment

Material

A

Contract

Book

was

created

that

contained

the

project

brief

the

customers

needs

the

details

of

the

selected

concept

the

development

schedule

and

deadlines

the

product

specifications

the

economic

analysis

of

the

product

the

project

staffing

and

the

budget

-LRB-

Ulrich

and

Eppinger

p.

-RRB-

Information

came

from

Electrolux

similar

products

competitors

suppliers

and

customers

It

was

mostly

printed

information

Similar

products

on

the

market

or

competitors

products

were

used

for

evaluation

benchmarking

and

reversal

engineering

always

in

three-dimensional

volumes

Files

in

the

computer

containing

drawings

of

other

products

and

parts

already

developed

by

the

company

were

studied

Drawings

of

parts

already

defined

and

chosen

to

feature

in

the

product

to

be

developed

such

as

motor

filter

keys

and

buttons

wire

and

so

on

were

also

studied

Equipment

PC

computers

and

workstations

running

CAD

programs

Workstations

running

CAM

programs

Conventional

or

CNC

machine

tools

not

under

DNC

linked

control

Physical

communication

devices

These

devices

must

support

all

the

messages

listed

below

and

common

knowledge

must

be

available

about

how

they

function

correctly

Computer

programs

Fax

machine

Telephone

machine

Courier

services

for

documents

drawings

and

models

Shared

workspace

In

these

workspaces

messages

are

transmitted

and

received

in

an

asynchronous

mode

or

in

the

case

of

face-to-face

meetings

a

synchronous

mode

Telephone

calls

Document

papers

Drawings

and

blueprints

Books

and

magazines

Facsimiles

Photos

of

models

and

products

Other

products

-LRB-

from

the

company

from

competitors

or

similar

products

-RRB-

Mock-ups

models

prototypes

and

so

on

Environment

Inside

the

organization

offices

laboratories

and

shop

floor

Outside

the

organization

design

office

model

and

prototype

workshop

suppliers

and

customers

places

Australian

factory

and

so

on

The

output

of

this

particular

product

development

process

was

basically

two

items

A

pilot

product

and

its

complete

specifications

Knowledge

and

experience

to

be

recorded

and

the

development

of

project

capability

PROCESS

DESCRIPTION

The

project?s

brief

and

schedule

were

an

input

to

the

process

They

stated

that

the

lead

time

of

the

product

development

should

be

thirty

days

A

further

thirty

days

should

then

be

allocated

for

the

prototyping

testing

of

the

prototype

production

of

the

pilot

product

and

its

final

blueprints

The

blueprints

comprised

all

the

conclusive

product

specifications

for

the

acquisition

of

molds

and

tools

Figure

shows

how

communication

in

the

final

stage

of

this

particular

product

development

process

evolved

and

it

is

described

in

detail

below

Electrolux

sent

ENG

to

the

DES

office

DES

did

not

have

professionals

sufficiently

skilled

and

with

great

technical

experience

in

vacuum

cleaner

products

There

was

much

information

that

had

been

generated

inside

Electrolux

which

is

known

to

be

a

technology

excellence

center

in

this

field

In

this

first

stage

the

communication

process

occurred

mainly

in

three

ways

DES

worked

with

his

own

computer

which

was

not

connected

to

a

network

in

the

same

room

as

ENG

who

used

a

drawing

board

for

the

detail

design

Drawing

boards

were

also

used

for

sketching

out

new

concepts

and

the

exchange

of

ideas

That

exchange

occurred

mainly

through

transfers

of

drawings

on

paper

and

therefore

DES

and

ENG

could

not

work

concurrently

on

the

same

file

Each

one

developed

an

element

mainly

in

sequence

and

seldom

in

parallel

DES

needed

to

plot

its

drawing

file

and

finally

ENG

joined

all

the

information

in

a

final

drawing

on

paper

that

included

various

pieces

of

drawing

by

DES

There

was

also

transfer

of

data

files

on

disks

which

occurred

between

the

computers

of

the

DES

office

Other

exchange

was

oral

through

face-to-face

chat

and

discussions

about

specific

items

Face-to-face

chat

is

different

from

telephone

chat

and

face-to-face

meetings

Unlike

the

telephone

chat

it

is

done

in

the

presence

of

both

interlocutors

Communication

is

done

mainly

through

chat

not

including

presentation

of

materials

and

conversation

is

conducted

between

two

people

whereas

meetings

are

considered

to

be

between

at

least

three

people

Figure

Communication

in

the

final

stage

of

a

vacuum

cleaner

development

process

at

Electrolux-Italy

The

last

mode

of

communication

at

that

stage

and

perhaps

the

most

important

one

occurred

in

the

model

workshop

contiguous

to

the

DES

office

DES

and

ENG

met

there

to

observe

and

discuss

the

product?s

last

volumetric

results

DES

generated

the

drawings

that

ENG

sequentially

modified

and

transformed

into

optimal

specifications

for

manufacturing

DES

was

then

in

charge

of

performing

the

changes

in

the

drawings

in

order

to

be

understood

by

the

model

maker

The

drawings

were

plotted

and

brought

to

the

adjacent

model

workshop

and

finally

the

model

maker

prepared

the

model

The

model

maker

called

the

ENG

and

the

DES

from

time-to-time

to

ask

any

questions

that

came

up

Once

a

day

MAN

passed

by

the

DES

office

in

order

to

observe

the

project

evolution

to

make

suggestions

or

clarify

any

manufacturing

issue

and

to

control

the

schedule

and

deadlines

He

would

then

report

to

the

Electrolux

chairperson

Occasionally

MAN

also

brought

some

information

or

objects

necessary

to

the

project

that

could

be

found

just

in

Electrolux

even

if

it

was

a

courier

service?s

task

Communication

also

took

place

on

the

telephone

between

DES

ENG

and

MAN

to

clarify

any

doubts

and

confirm

any

information

that

occasionally

came

up

The

conversations

occurred

separately

between

the

interlocutors

because

it

was

not

possible

for

more

than

two

people

to

discuss

on

the

telephone

The

telephone

was

also

used

to

arrange

meetings

discuss

any

changes

in

the

design

document

and

explain

details

Some

meetings

took

place

to

present

the

models

either

in

the

DES

office

or

on

the

Electrolux

premises

although

they

were

not

very

frequent

due

to

the

brevity

of

the

project

lead

time

There

was

also

a

need

to

transmit

some

drawings

and

documents

by

fax

-LRB-

out

of

scale

-RRB-

to

show

some

project

issues

In

Figure

the

communication

by

telephone

between

DES

ENG

and

MAN

is

represented

by

a

thin

solid

black

arrow

with

a

symbol

te

The

communication

by

fax

between

DES

and

ENG

has

the

symbol

fa

The

meetings

that

grouped

the

DES

ENG

MAN

and

sometimes

the

model

maker

are

represented

by

a

thick

solid

black

arrow

with

a

symbol

me

It

differs

from

the

other

thin

arrows

because

the

meetings

will

continue

to

exist

even

after

the

implementation

of

the

digital

communication

process

After

the

presentation

of

the

final

model

and

the

approval

by

the

Italian

Electrolux

top

management

and

Board

of

Directors

the

operation

moved

to

Electrolux

The

ENG

took

back

his

workstation

and

developed

the

conclusive

drawings

for

the

prototype

construction

ENG

and

MAN

still

exchanged

important

information

using

transfers

of

drawings

on

paper

therefore

not

working

concurrently

Once

more

as

occurred

in

the

DES

office

an

important

part

of

the

work

could

not

be

done

concurrently

This

fact

increased

the

lead-time

of

the

process

and

reduced

the

collaboration

and

cooperation

between

the

people

involved

Communication

also

occurred

through

brief

meetings

in

which

the

discussion

needed

the

drawings

on

paper

There

was

still

some

communication

between

ENG

and

DES

for

confirmation

of

details

on

the

telephone

or

through

the

transmission

of

drawings

by

fax

or

through

a

courier

service

Transportation

took

up

much

precious

time

Finally

the

drawings

for

the

prototype

construction

were

plotted

obtaining

DES

and

ENG

sign-off

Then

MAN

approved

the

drawings

and

released

them

to

the

firm

selected

by

competitive

bidding

to

be

in

charge

of

constructing

an

accurate

prototype

of

the

product

designed

The

product

model

traveled

around

the

globe

-LRB-

England

France

and

Australia

-RRB-

to

be

accepted

for

local

business

In

the

meantime

MAN

made

contact

with

subcontractors

especially

for

the

fabrication

of

the

shampoo

and

water

recipient

which

was

the

bottleneck

It

required

an

innovative

production

technology

that

Electrolux

did

not

want

to

develop

inhouse

MAN

also

searched

for

the

production

of

other

parts

of

the

product

In

the

case

of

the

recipient

for

example

the

high

cost

and

scarcity

of

producers

with

technology

of

welding

process

of

the

two

halves

by

ultrasound

generated

the

need

to

search

for

an

alternative

technology

like

the

hot

blade

This

new

technology

required

substantial

alterations

in

the

product

project

for

those

pieces

and

by

extension

to

other

parts

ENG

sent

the

changes

needed

by

fax

to

DES

and

he

sent

the

drawings

with

the

sketches

of

possible

solutions

to

the

problem

that

emerged

by

courier

service

He

had

to

wait

for

the

return

of

the

model

that

was

abroad

which

was

needed

for

the

model

construction

of

the

new

recipient

DES

made

three

other

models

of

the

recipient

through

orientation

and

drawings

of

ENG

and

MAN

They

came

to

the

workshop

to

speed

up

the

approval

of

the

best

solution

that

fitted

the

requirements

of

the

new

technology

employed

ENG

-LRB-

through

interchange

with

MAN

-RRB-

developed

new

drawings

A

courier

service

delivered

the

drawings

together

with

the

new

model

to

the

prototypist

that

was

already

in

the

final

stages

of

the

prototype

construction

The

prototype

was

tested

in

the

Electrolux

laboratory

-LRB-

controlled

by

MAN

-RRB-

ENG

required

some

minor

changes

that

were

carried

out

and

the

Electrolux

Board

of

Directors

and

C.E.O.

together

with

DES

ENG

and

MAN

approved

it

MAN

searched

for

the

construction

of

molds

for

the

production

of

a

pilot

product

He

kept

touch

by

telephone

with

DES

and

ENG

every

time

a

problem

that

harmed

the

project

appeared

in

the

manufacture

Later

MAN

sent

samples

by

courier

service

to

the

DES

and

the

ENG

These

samples

were

colors

and

injected

pieces

for

the

conclusive

analysis

judgment

and

choice

of

the

best

solutions

After

the

necessary

decisions

were

taken

a

pilot

product

was

produced

the

final

detailed

drawings

of

the

product

with

all

the

specifications

were

drawn

up

signed

and

authenticated

Printed

copies

of

these

drawings

were

archived

in

the

ENG

office

and

sent

to

the

DES

After

the

production

of

a

pilot

product

everything

was

brought

together

to

see

if

it

worked

as

planned

in

a

pilot

run

As

the

pilot

run

was

successful

it

was

followed

by

ramp-up

that

was

the

start-up

of

commercial

production

After

the

beginning

of

mass

production

MAN

detected

some

inevitable

changes

and

immediately

communicated

them

to

ENG

Some

decisions

of

changes

in

the

product

were

taken

after

many

meetings

which

implied

in

losses

in

terms

of

time

and

money

because

many

pieces

had

been

already

produced

This

time

lag

in

the

detection

of

the

problem

was

mainly

due

to

the

lack

of

or

difficulty

in

communication

between

the

shop

floor

and

MAN

ENG

and

DES

They

were

all

physically

distant

After

correcting

the

molds

and

re-starting

mass

production

the

production

batches

ordered

by

the

foreign

branches

of

Electrolux

were

finally

delivered

It

should

be

noted

that

one

team

designed

the

whole

product

There

were

not

different

teams

designing

subassemblies

subject

to

common

design

goals

and

constraints

The

coordination

of

different

teams

highly

increases

the

process

complexity

and

would

benefit

even

more

from

digital

communication

technology

Once

different

component

designs

have

been

set

in

process

any

further

change

to

one

of

them

should

have

a

proper

notification

accompanying

it

to

those

in

charge

of

all

other

component

designs

that

the

change

could

affect

Oversights

of

the

changes

lead

to

delays

downstream

when

incompatibilities

or

conflicts

are

discovered

Through

digital

communication

all

affected

parties

may

immediately

be

notified

of

any

changes

made

to

the

design

brief

and

subassemblies

design

THE

DIGITAL

COMMUNICATION

PROCESS

The

digital

communication

process

and

computer

networking

are

new

communication

technologies

These

technologies

will

lead

to

long-term

changes

in

the

way

that

people

work

together

They

touch

the

most

critical

process

in

an

organization

the

way

people

communicate

Nevertheless

it

is

difficult

to

understand

how

computer

technology

will

interact

with

ongoing

routine

practices

and

policies

in

organizations

There

are

some

experiments

being

carried

out

but

very

few

studies

analyzing

its

real

effects

Sproull

and

Kiesler

-LRB-

-RRB-

point

out

that

this

change

in

the

way

people

communicate

has

first

and

second-level

effects

First-level

effects

refer

to

efficiency

changes

consisting

of

productivity

gains

which

conventional

cost-displacement

or

value-added

analysis

often

underestimates

their

calculations

Second-level

effects

refer

to

social

and

organizational

changes

that

they

consider

to

be

more

important

to

the

organization

as

employees

cross

barriers

of

space

time

and

social

category

to

share

expertise

opinions

and

ideas

If

an

organization?s

business

is

stable

or

if

it

is

operating

within

a

placid

environment

with

long

lead

times

before

predictable

changes

in

markets

suppliers

or

customers

then

diverse

dynamic

group

structures

make

little

sense

An

organization

that

is

operating

in

a

turbulent

unpredictable

environment

however

will

find

that

the

network

can

become

a

powerful

strategic

tool

for

flexible

management

-LRB-

Sproull

and

Kiesler

-RRB-

De

Meyer

-LRB-

-RRB-

remarked

that

it

is

often

argued

that

the

greatest

savings

in

the

reduction

of

development

times

can

be

made

in

the

interfaces

between

the

different

company

functions

involved

in

the

development

process

Digital

communication

improves

the

interfaces

in

the

product

development

process

through

collaborative

and

cooperative

work

admitting

mutual

and

constant

consulting

of

the

design

engineering

and

manufacturing

departments

and

the

sharing

of

knowledge

Therefore

it

stimulates

concurrent

engineering

understood

as

a

way

to

conduct

the

design

work

where

the

various

activities

related

to

the

product

realization

process

are

integrated

and

performed

as

much

as

possible

in

parallel

rather

than

in

sequence

-LRB-

Naveiro

and

O?Grady

-RRB-

It

can

then

can

be

used

to

increase

personal

connections

and

affiliations

Computers

provoke

intense

communication

that

allows

different

aspects

of

a

project

to

be

carried

out

at

the

same

time

rather

than

sequentially

therefore

the

project

can

proceed

rapidly

through

overlapping

and

parallel

activities

Clark

Chew

and

Fujimoto

-LRB-

-RRB-

showed

in

their

comparative

study

of

automobile

development

projects

in

Japan

the

United

States

and

Western

Europe

that

Japan

leads

the

United

States

and

Europe

in

its

ability

to

get

products

to

the

market

faster

and

more

efficiently

Japanese

project

teams

use

intense

formal

and

informal

information

transfer

both

within

R&D

and

between

R&D

and

production

allowing

for

coordination

while

preventing

too

many

surprises

that

could

delay

the

project

Clark

Chew

and

Fujimoto

-LRB-

-RRB-

reveal

that

information

moves

less

quickly

between

design

engineering

and

the

prototype

unit

in

U.S.

firms

On

the

other

hand

when

the

product

design

changes

during

the

prototype

process

in

a

typical

Japanese

company

design

engineers

instruct

the

shop

technicians

directly

about

the

changes

without

waiting

for

paperwork

COMMUNICATION

STRUCTURE

Communication

will

occur

basically

through

computers

connected

to

one

another

through

an

information

transport

medium

that

carries

packages

of

information

in

a

network

This

network

may

be

internal

to

the

organization

at

the

beginning

and

afterwards

external

connecting

the

organization

with

its

suppliers

outsourcers

and

clients

converting

them

into

partners

in

the

development

process

The

physical

communication

device

will

be

just

the

computer

with

its

software

network

and

telephone

line

The

computer

will

incorporate

the

telephone

and

fax

machine

The

telephone

line

and

a

modem

will

be

necessary

mainly

for

the

communication

between

the

worker?s

house

and

the

firm

This

communication

will

take

place

through

the

Internet

Besides

the

computer

courier

services

will

continue

to

be

used

for

delivering

documents

drawings

and

various

objects

The

transmission

the

reception

and

also

the

shared

workspace

will

all

be

in

a

digital

format

The

shared

workspace

may

include

chats

documents

and

drawings

magazines

books

facsimiles

photos

of

the

model

and

other

products

and

so

on

The

models

the

prototypes

and

other

three-dimensional

products

will

be

delivered

by

courier

service

Digital

communication

will

link

the

separate

functions

of

design

engineering

and

manufacturing

in

a

horizontal

cross-functional

process

of

product

development

that

reduces

the

conflicts

and

divisiveness

between

the

organizational

sub-units

The

integration

is

attained

through

multiple

group

membership

promoting

cooperation

and

cohesion

between

the

separate

departments

Face-to-face

meetings

will

continue

to

be

held

even

when

digital

communication

will

be

the

main

communication

format

It

would

be

necessary

initially

for

the

constitution

of

project

teams

to

secure

commitment

to

the

team?s

goals

and

to

decompose

the

tasks

into

parts

Later

each

participant

of

this

process

stage

will

work

in

his

office

in

his

department

connected

internally

to

the

organization

and

externally

to

the

other

participants

through

a

computer

that

will

mediate

the

digital

communication

People

will

be

connected

because

of

shared

interest

rather

than

proximity

working

in

a

decentralized

way

even

geographically

using

the

network

to

integrate

the

different

professionals

Other

face-to-face

meetings

can

be

held

for

a

final

design

review

or

a

decision

such

as

the

start-up

of

the

commercial

production

They

will

be

more

focused

and

rigorous

because

participants

should

exchange

information

digitally

before

the

meetings

to

clear

up

misunderstandings

prune

away

distractions

and

identify

the

key

issues

The

Internet

will

constitute

the

external

communication

network

of

the

organization

and

an

intranet

will

be

a

corporate

internal

service

The

intranet

is

like

private

World

Wide

Web

servers

-LRB-

from

now

on

just

Web

-RRB-

that

copy

the

Internet

model

but

offer

access

just

to

the

authorized

users

of

the

local

internal

network

of

the

organization

The

intranet

also

offers

the

possibility

of

communicating

with

the

Internet

because

they

are

harmoniously

complementary

There

will

still

be

other

networks

inside

the

intranet

separate

local

area

networks

for

each

of

several

functional

sub-units

available

for

sectors

departments

or

projects

It

will

treat

a

specific

subject

with

confidential

information

that

must

not

go

inadvertently

to

inappropriate

people

Compartmentalizing

the

networks

should

help

protect

integrity

and

confidentiality

of

data

The

organization

will

need

to

hire

a

webmaster

and

technical

staff

to

build

and

maintain

the

external

and

internal

communication

system

In

the

following

delineation

the

webmaster

and

staff

were

combined

into

the

webmaster

person

in

the

same

way

was

done

in

the

process

description

where

the

departments

were

combined

into

the

manager

person

of

each

function

The

position

of

the

webmaster

is

becoming

a

more

senior-level

position

with

the

person

being

responsible

for

managing

the

evolution

and

well-being

of

the

Web

work

as

well

as

the

more

traditional

HTML

and

other

technical

work

In

some

organizations

the

webmaster

has

a

senior

level

position

which

is

expected

to

become

more

commonplace

as

the

Web

becomes

critical

to

the

success

of

a

company

's

information

environment

COMMUNICATION

REQUIREMENTS

The

digital

communication

external

and

internal

will

be

based

on

the

Web

and

the

utilization

of

some

Winsock

application

software

-LRB-

like

Netscape

Navigator

and

Eudora

products.html

-RRB-

that

speaks

the

Internet

language

The

external

and

internal

communication

refers

respectively

to

the

Internet

and

the

intranet

For

communication

between

the

worker?s

house

and

the

firm

each

computer

should

have

a

SLIP/PPP

connection

Requirements

of

connectivity

are

available

on

the

TCP/IP

network

and

at

the

IP

address

Requirements

of

hardware

for

Windows

environment

are

PC

with

processor

or

better

colors

-LRB-

-RRB-

video

with

resolution

or

better

sound

card

fullduplex

with

input

to

microphone

and

output

to

speaker

-LRB-

internal

or

external

-RRB-

and

compatible

to

Windows

memory

connection

with

IP

network

-LRB-

Windows

Socket

compatible

with

TCP/IP

architecture

-RRB-

QuickCam

or

FlexCam

cameras

with

microphone

separated

from

the

camera

speakers

printer

plotter

and

scanner

For

the

house-firm

communication

a

k

modem

or

faster

will

be

needed

as

well

as

the

Windows

Socket

having

kb

band

or

better

and

being

SLIP/PPP

compatible

SERVICES

Through

the

communication

structure

described

above

with

a

client-server

configuration

and

using

some

application

software

all

participants

of

the

product

development

process

can

be

physically

dispersed

and

with

divided

responsibilities

Some

communication

modes

such

as

face-to-face

chat

telephone

chat

fax

transmission

drawings

on

a

drawing

board

and

transfer

of

data

files

on

disks

besides

the

transportation

of

drawings

and

disks

will

all

be

substituted

by

digital

communication

-LRB-

Figures

and

-RRB-

The

necessity

of

face-to-face

meetings

will

be

greatly

reduced

and

will

continue

to

occur

but

only

when

really

necessary

and

they

will

be

arranged

through

digital

communication

In

addition

digital

communication

will

bring

the

marketing

departments

of

Electrolux

in

Australia

England

and

France

to

the

product

development

process

In

the

present

process

the

foreign

marketing

departments

are

major

clients

of

the

project

but

they

are

very

distant

and

just

buyers

of

the

product

In

the

process

integrated

by

digital

communication

they

will

become

major

participants

in

the

whole

process

In

the

process

described

design

and

engineering

could

not

work

concurrently

on

the

same

drawing

Through

digital

communication

concurrent

engineering

may

become

the

norm

The

delays

downstream

that

occurred

when

incompatibilities

or

conflicts

were

discovered

may

not

happen

anymore

as

digital

communication

can

immediately

notify

all

the

affected

parties

whenever

a

change

is

made

In

the

same

way

the

problems

discovered

downstream

that

required

a

lot

of

time

until

they

are

known

upstream

can

be

fixed

quickly

when

digital

communication

is

established

Figure

Digital

communication

improving

the

information

flow

in

the

product

development

process

Through

a

Web

browser

interface

and

using

application

software

a

memory

section

a

project

section

and

a

rules

and

routines

section

of

the

corporation

everyone

involved

in

the

product

development

process

will

have

the

capacity

to

do

the

following

Browser

Access

information

through

a

browser

visualizing

another

computer

through

a

monitoring

program

-LRB-

when

it

has

been

authorized

-RRB-

transferring

and

retrieving

files

through

a

FTP

client

visualizing

and

working

on

them

through

viewers

and

many

editors

discussing

information

through

IRC

or

on

the

Internet

Phone

transmitting

it

via

electronic

mail

and

working

concurrently

on

the

same

drawing

through

a

whiteboard

or

even

a

video

conference

program

Go

across

the

net

concurrently

for

joint

research

about

some

fabrication

process

or

information

on

technologies

and

their

experts

through

the

search

instrument

in

a

browser

managed

by

a

chat

program

-LRB-

-RRB-

Memory

Help

produce

one

of

the

main

outputs

of

the

product

development

process

consisting

of

knowledge

and

experience

to

be

recorded

The

same

group

memory

is

available

to

every

member

of

the

group

Through

electronic

mail

it

is

possible

to

archive

the

complete

text

of

every

message

and

automatically

document

entire

discussions

which

are

invaluable

in

the

preparation

of

reference

manuals

Through

built-in

external

memory

electronic

messages

can

be

stored

and

later

retrieved

thus

encompassing

a

social

memory

and

organizational

memory

can

ensure

consistency

across

time

and

units

Project

Find

a

problem

downstream

in

the

manufacturing

process

and

fix

it

upstream

quickly

saving

a

lot

of

time

and

money

Digital

communication

technology

is

very

fast

and

accelerates

the

information

flow

-LRB-

Sproull

and

Kiesler

-RRB-

Share

information

about

production

issues

while

dealing

with

different

languages

cultures

and

time

zones

in

the

different

product

development

and

manufacturing

locations

The

advantage

of

the

Web?s

documents

ability

to

embed

graphics

and

hyperlink

references

to

other

documents

in

these

cases

is

powerful

Keep

people

up-to-date

with

the

others

progress

and

problems

in

between

meetings

through

electronic

mail

reports

of

accomplished

tasks

Rules

and

routines

Hold

meetings

electronically

rather

than

face-to-face

solving

the

problem

of

finding

an

available

day

for

a

meeting

when

all

the

relevant

people

can

attend

because

people

are

busy

and

in

different

locations

Publish

something

and

wait

for

someone

to

draw

or

to

work

upon

it

after

one

stops

working

and

goes

home

without

the

need

to

bother

the

collaborators

in

improper

hours

thus

linking

different

time

zones

This

is

possible

because

digital

communication

technology

can

be

used

in

an

asynchronous

way

so

that

both

parties

to

a

communication

do

not

have

to

be

available

simultaneously

for

it

to

occur

They

can

send

and

receive

at

their

convenience

Nevertheless

as

this

technology

is

very

fast

it

can

approximate

real-time

interaction

Put

all

meeting

minutes

presentations

and

project

plans

on

the

Web

where

anyone

can

access

them

when

they

need

to

It

is

also

possible

to

disseminate

information

to

groups

such

as

departments

through

electronic

distribution

lists

without

needing

to

distribute

documents

on

paper

or

send

e-mail

with

large

attachments

This

is

possible

because

digital

communication

technology

makes

one-to-many

communication

as

easy

as

one-to-one

communication

Even

previously

ad

hoc

communication

can

become

routine

Order

material

parts

prototypes

molds

products

and

so

on

directly

from

the

desktop

possibly

visualizing

on

the

screen

what

is

available

in

the

stockroom

or

how

long

it

will

take

to

arrive

It

is

also

possible

to

make

use

of

a

global

procurement

organization

ESTABLISHING

THE

COMMUNICATION

PROCESS

The

traditional

communication

modes

in

the

product

development

process

by

means

of

face-to-face

meetings

telephone

calls

fax

transmission

and

exchanges

through

courier

service

slow

down

product

development

and

increase

lead

times

in

two

fundamental

ways

Firstly

communication

takes

a

great

deal

of

time

for

the

reasons

outlined

above

which

include

conventional

mailing

delays

difficulty

to

arrange

meetings

the

need

to

translate

different

formats

and

scales

and

so

on

Secondly

communication

is

hindered

by

temporal

and

geographic

distance

of

the

participants

in

the

process

The

difficulty

to

communicate

leads

to

problems

such

as

those

described

above

If

a

change

is

needed

in

the

product

design

it

is

detected

only

after

the

pilot

production

run

whereas

this

could

be

avoided

if

the

decisions

upstream

were

communicated

downstream

before

they

were

taken

A

digital

communication

process

is

outlined

in

order

to

solve

these

problems

of

delay

in

the

product

development

process

Although

the

proposed

use

of

this

technology

is

relatively

new

there

is

strong

evidence

in

literature

-LRB-

Sproull

and

Kiesler

Clark

Chew

and

Fujimoto

De

Meyer

-RRB-

and

in

its

application

in

corporations

such

as

AT&T

Olivetti

and

others

that

digital

communication

integrating

design

engineering

and

manufacturing

can

greatly

reduce

lead

times

in

the

product

development

process

through

concurrent

engineering

and

overlapping

activity

AT&T

-LRB-

html

-RRB-

uses

digital

communication

and

the

Web

for

countless

internal

applications

These

applications

include

an

interface

to

accessing

library

services

doing

internal

research

receiving

external

news

feeds

accessing

database

ordering

supplies

putting

papers

available

to

be

browsed

authenticating

internal

projects

and

so

on

It

has

enabled

AT&T

employees

to

collaborate

more

effectively

even

on

complex

projects

and

it

has

improved

the

efficiency

of

research

and

development

by

helping

people

work

together

Olivetti

-LRB-

olivetti.html

-RRB-

uses

a

browser-based

intranet

to

create

a

single

virtual

laboratory

that

links

together

Olivetti?s

research

laboratories

located

throughout

Italy

and

abroad

Researchers

use

the

intranet

to

access

product

development

information

debate

topics

in

dedicated

discussion

areas

and

share

experiences

and

projects

results

with

their

colleagues

regardless

of

their

location

The

product

development

can

be

done

in

teams

and

the

project

leader

has

instantly

administrative

data

on

his

project

such

as

expenses

work

hours

spent

and

status

of

procurement

requests

This

communication

technology

allows

project

teams

to

focus

more

on

technical

problems

than

on

administrative

issues

increasing

the

productivity

and

efficiency

of

operations

THE

WEB

ENVIRONMENT

It

is

essential

that

people

spend

their

time

at

work

on

the

product

development

designing

engineering

manufacturing

the

product

and

even

just

communicating

People

should

not

waste

time

struggling

to

learn

how

to

use

the

computer

and

the

tools

available

We

believe

that

the

Web

browser

interface

is

becoming

standard

and

a

culture

of

using

this

interface

is

in

the

process

of

being

molded

The

operating

systems

and

their

services

will

disappear

and

the

browser

interface

will

be

common

to

everyone

although

it

will

be

customized

to

every

particular

use

and

user

For

these

reasons

the

main

interface

between

the

user

and

the

work

he

wants

to

do

will

be

the

Web

browser

In

this

way

the

user

will

not

need

to

learn

a

different

interface

every

time

he

simply

wants

to

do

some

work

Every

participant

in

the

product

development

process

may

sit

at

his

work

station

turn

on

his

computer

on

his

desktop

and

be

able

to

work

directly

on

his

project

as

the

one

in

the

working

space

presented

in

Figure

The

user?s

working

space

will

encompass

all

the

interfaces

needed

for

the

product

development

and

its

communication

process

The

first

window

with

its

initial

page

shows

the

project

being

developed

in

a

CAD

session

where

for

example

the

designer

may

need

to

ask

the

engineer

which

plastic

section

would

be

needed

for

the

model

in

case

The

Web

browser

is

placed

at

the

top

of

the

window

and

functions

as

an

integrative

program

The

search

and

search

in

group

commands

are

placed

just

below

it

They

are

useful

for

researching

the

Internet

and

the

intranet

These

instruments

also

enable

joint

research

about

some

fabrication

process

for

example

when

design

and

manufacturing

may

search

for

different

qualities

in

the

process

This

kind

of

research

group

work

is

fundamental

when

it

involves

crossfunctional

teams

and

workers

in

different

locations

that

produce

more

and

better

products

when

integrated

The

communication

process

in

Electrolux-Italy

did

not

stimulate

the

group

work

for

researching

and

collecting

information

Next

to

the

search

keys

there

is

a

special

key

that

provides

immediate

contact

with

the

webmaster

and

staff

As

explained

above

the

users

should

do

the

work

they

are

interested

in

doing

Therefore

they

may

need

to

contact

the

webmaster

for

help

and

to

solve

any

problem

that

may

appear

which

disturbs

the

work

development

The

other

communication

modes

through

the

software

applications

are

easily

accessed

through

a

toolbox

that

can

be

placed

anywhere

in

the

window

as

well

as

in

any

program

in

use

The

toolbox

functionality

is

independent

of

the

current

program

in

use

The

user

may

be

working

in

a

spreadsheet

and

use

the

toolbox

to

talk

to

someone

in

the

same

way

he

would

do

if

he

was

working

in

a

CAM

program

The

interface

will

always

function

in

the

same

way

to

avoid

constant

re-adaptation

THE

WORKING

SPACE

Figure

shows

a

window

with

a

working

space

example

that

epitomizes

how

the

digital

communication

process

is

established

Work

in

the

digital

space

begins

with

immediate

access

to

the

Web

It

is

the

primary

interface

between

the

user

and

the

work

he

wants

to

do

There

are

two

keys

related

to

the

search

instruments

of

the

Web

browser

The

designer

may

want

to

learn

a

specification

of

a

product

section

from

a

plastic

producer

thus

searching

for

his

home

page

with

the

search

command

He

may

also

search

for

other

producers

together

with

other

members

of

the

team

using

the

search

in

group

command

It

can

be

used

to

go

across

the

net

in

group

as

well

as

to

search

for

files

inside

the

user?s

computer

and

every

database

in

the

organization

The

user

may

want

to

reach

the

webmaster

frequently

as

he

may

need

help

to

continue

work

on

the

project

which

is

the

most

important

process

Another

user

may

have

written

a

report

on

a

new

product

and

edited

the

report

in

HTML

through

the

editor

in

the

toolbox

wanting

the

webmaster

to

make

it

available

on

the

Web

server

and

so

on

Therefore

a

special

key

that

signifies

a

hotline

to

the

webmaster

is

provided

Recent

and

important

news

is

broadcasted

for

those

people

who

may

be

interested

in

reading

it

such

as

the

design

review

meeting

is

starting

in

room

X

The

news

is

frequently

fed

into

this

window

and

messages

such

as

you

have

new

mail

may

be

shown

in

this

space

as

well

The

designer

may

receive

a

note

broadcasted

to

him

that

an

important

meeting

that

requires

his

presence

is

being

held

in

the

meeting

room

He

may

use

the

electronic

mail

from

the

toolbox

to

send

the

drawing

with

a

model

attached

to

a

message

to

another

member

of

the

project

team

in

another

place

In

this

message

he

may

ask

to

continue

the

drawing

and

to

search

for

the

information

needed

while

he

is

out

at

a

meeting

The

largest

working

space

is

addressed

to

every

program

of

interest

to

the

user

such

as

the

CAD

program

in

Figure

or

a

word

processor

and

so

on

Each

user

may

have

one

cursor

for

concurrent

use

and

communication

The

user

should

not

need

to

use

other

programs

to

mediate

the

access

to

the

real

programs

he

may

want

to

use

for

his

work

or

for

the

documents

he

is

working

on

The

communication

will

be

accomplished

through

a

toolbox

comprising

software

of

the

following

applications

electronic

mail

browser

chat

newsgroup

videoconference

monitoring

FTP

client

VRML

viewer

HTML

editor

and

a

compressor

The

toolbox

will

be

displayed

not

only

on

the

first

page

but

also

in

every

program

window

in

use

in

the

computer

The

user

will

access

the

software

directly

through

ten

commands

that

are

available

for

immediate

use

He

will

use

it

to

communicate

internally

in

the

organization

and

externally

to

every

participant

in

the

project

From

inside

the

program

through

the

toolbox

the

designer

may

compress

the

file

with

the

drawing

of

the

product

part

he

made

in

the

CAD

program

then

opening

the

FTP

dialog

box

and

sending

the

drawing

to

the

manufacturing

department

He

may

later

call

through

the

phone

program

to

ask

if

the

extraction

angle

in

the

drawing

is

right

He

may

finally

send

a

mail

to

the

project?s

electronic

distribution

list

informing

the

other

people

of

the

changes

he

made

to

the

drawing

of

part

B

and

where

it

is

available

for

concurrent

work

The

user

may

need

quick

research

or

information

from

some

important

sections

Therefore

there

is

a

frame

containing

the

five

main

sections

that

are

essential

for

the

product

development

process

In

every

page

of

the

Web

there

will

be

a

horizontal

frame

at

the

top

of

the

page

with

immediate

access

to

any

one

of

these

five

main

sections

The

designer

may

consider

visiting

the

memory

section

to

see

if

a

problem

like

the

one

mentioned

above

has

ever

happened

in

the

corporation

He

may

learn

the

solution

recorded

before

bothering

the

engineer

with

his

question

The

following

sections

are

available

for

immediate

access

from

any

program

in

use

Corporation

In

the

corporation

section

corporate

applications

that

are

loaded

in

HTML

-LRB-

Hypertext

Markup

Language

-RRB-

are

available

from

SQL

-LRB-

Structured

Query

Language

-RRB-

applications

of

relational

databases

or

from

UNIX

applications

and

are

multiplatform

compatibles

This

way

distributed

database

and

data

processing

systems

resident

in

one

computer

are

available

to

people

at

a

distance

and

other

computers

via

network

The

applications

constructed

in

HTML

are

truly

interoperable

solutions

capable

of

allowing

different

kinds

of

machines

to

easily

share

the

same

data

-LRB-

it

does

not

matter

if

they

are

PCs

Macs

workstations

UNIX

etc.

-RRB-

There

is

environment

compatibility

and

through

Web

technology

it

is

possible

to

load

an

application

in

a

Web

server

and

later

each

desktop

with

a

Web

browser

can

access

this

application

through

the

existing

network

Departments

In

the

departments

section

each

division

or

department

in

the

organization

has

a

page

where

current

projects

services

processes

and

guidelines

are

described

Besides

that

every

worker

has

an

e-mail

address

and

even

a

home

page

depending

on

his

or

her

function

in

the

organization

When

the

information

is

available

in

any

department

it

is

shown

in

the

department?s

section

Otherwise

it

is

sent

by

electronic

distribution

lists

to

whom

it

is

of

interest

helping

to

accelerate

the

product

development

process

Information

will

also

be

broadcast

and

discussed

in

electronic

interacting

groups

Projects

The

section

relative

to

the

product

project

being

developed

contains

all

the

information

that

the

people

involved

in

this

process

will

share

This

information

may

be

product

brief

with

design

goals

and

constraints

project

schedule

and

time

deadlines

project

budget

stages

of

the

product

development

process

and

benchmarks

As

the

project

advances

new

pertinent

information

becomes

available

such

as

prototype

tests

and

marketing

research

results

bugs

in

the

manufacturing

date

of

the

first

batch

production

lists

of

the

work

in

progress

and

so

on

This

information

is

constantly

updated

and

reformulated

like

a

big

and

distributed

database

where

everyone

can

access

it

and

contribute

to

it

This

is

particularly

valuable

when

for

example

the

design

group

is

located

in

Brazil

and

the

engineering

group

in

Sweden

When

the

design

project

is

finished

the

engineering

has

access

to

its

final

results

as

well

as

the

manufacturing

when

the

specifications

of

the

product

are

concluded

Everyone

that

is

part

of

the

project

team

or

related

to

it

can

follow

the

product

development

process

Each

department

does

not

have

to

wait

until

the

end

of

each

stage

to

give

its

opinion

and

contribution

or

show

any

concern

The

two-dimensional

materials

related

to

the

project

must

already

be

in

a

digital

mode

such

as

the

design

document

the

project

budget

the

project

schedule

and

time

deadlines

and

general

information

that

is

written

edited

signed

and

authenticated

electronically

It

may

also

be

scanned

like

photos

and

product

catalogs

The

drawings

must

be

in

a

CAD

program

format

to

make

it

possible

to

rework

and

make

changes

that

the

scanned

image

does

not

allow

Models

and

three-dimensional

products

can

be

video-taped

and

made

available

through

animation

or

image

files

to

be

visualized

by

a

viewer

or

showed

directly

through

a

video

conference

program

in

real

time

Rules

and

routines

This

section

comprises

all

the

design

rules

and

works

routine

files

that

are

standard

to

the

organization

and

available

to

everyone

related

to

each

particular

rule

and

routine

It

is

appropriate

that

all

parties

involved

in

the

development

process

have

equal

access

to

a

database

regarding

materials

processes

equipment

tools

market

data

and

other

relevant

information

These

files

may

also

include

forms

for

material

requirements

for

part

ordering

for

prototypes

authorizations

and

so

on

Memory

This

section

refers

to

the

corporation?s

memory

It

presents

everything

related

to

the

communication

and

product

development

process

that

should

be

recorded

and

transmitted

to

participants

for

future

projects

The

organization?s

memory

represents

one

of

the

main

outputs

of

the

product

development

process

It

may

be

transformed

into

knowledge

and

experience

that

may

compose

the

core

competence

of

the

manufacturing

organization

The

following

examples

are

presented

in

the

memory

section

every

discussion

about

an

essential

issue

in

the

product

development

recorded

in

the

electronic

mail

articles

in

a

newsgroup

that

were

important

to

solve

a

problem

a

voice

conference

where

a

breakdown

in

the

process

was

solved

and

so

on

This

knowledge

about

the

process

may

help

to

avoid

the

same

mistakes

occurring

in

another

project

or

speed

up

joining

a

solution

to

a

problem

previously

solved

CONCLUSION

Digital

communication

provides

means

to

effect

fast

decision-making

and

bring

action

to

where

the

competence

is

It

gives

instruments

to

the

users

that

enable

them

to

go

to

the

resources

they

want

rather

than

having

information

pushed

at

them

It

also

allows

project

leaders

to

focus

more

on

technical

problems

than

on

administrative

issues

The

results

of

establishing

digital

communication

can

be

a

more

effective

collaboration

even

on

complex

projects

because

it

stimulates

the

group

work

It

establishes

a

unified

approach

to

product

development

and

at

the

same

time

leads

to

creativity

It

fosters

the

knowledge

of

what

the

others

are

doing

sharing

relevant

knowledge

through

the

organization

and

recognizing

employees

participation

Design

engineering

and

manufacturing

do

not

need

to

work

on

the

same

site

They

can

be

geographically

separate

and

nevertheless

work

concurrently

on

the

same

project

using

digital

communication

Neither

do

they

need

to

work

at

the

same

time

A

designer

may

stop

work

to

go

home

and

send

the

drawing

he

was

working

on

to

another

member

of

the

project?s

team

Digital

communication

may

improve

the

product

development

process

through

concurrent

engineering

and

overlapping

activities

It

is

then

possible

to

reduce

the

lead

time

of

the

process

facilitating

clear

and

direct

communication

in

product

development

groups

It

also

accelerates

learning

and

getting

products

onto

the

market

thus

being

more

competitive

The

product

development

process

in

Electrolux-Italy

is

presently

using

computers

mainly

for

isolated

work

and

not

for

communication

as

described

in

this

paper

There

are

some

differences

from

the

time

of

the

project

process

analyzed

in

this

paper

to

the

way

the

product

is

developed

currently

The

detail

design

is

done

using

computers

and

CAD

programs

Design

engineering

and

manufacturing

each

have

their

own

computer

but

are

not

connected

to

a

network

The

exchange

occurs

mainly

through

file

transfer

on

disk

therefore

design

and

engineering

can

not

yet

work

concurrently

on

the

same

file

Each

one

develops

an

element

in

sequence

or

in

parallel

joining

all

the

information

in

a

final

file

created

by

engineering

which

includes

various

pieces

of

drawing

by

the

design

and

the

engineering

Information

between

engineering

and

manufacturing

is

exchanged

using

data

file

transfer

on

disk

without

working

concurrently

in

the

same

way

as

happens

between

design

and

engineering

Companies

such

as

AT&T

-LRB-

profiles/att

html

-RRB-

Silicon

Graphics

-LRB-

sgi.html

-RRB-

Olivetti

-LRB-

profiles/olivetti

html

-RRB-

Motorola

National

Semiconductor

-LRB-

comprod/at

work/customer

profiles/semicond

html

-RRB-

Allen-Bradley

McDonnell

Douglas

-LRB-

mcdonnell.html

-RRB-

and

Sandia

National

Labs

-LRB-

sandia.html

-RRB-

are

employing

several

modes

of

digital

communication

for

the

development

of

various

products

ACKNOWLEDGMENTS

The

authors

gratefully

acknowledge

the

Brazilian

Ministry

of

Education

-LRB-

CAPES

grant

social

demand

-RRB-

and

the

Brazilian

National

Research

Council

-LRB-

CNPq

grants

300 608/90

and

302 206/86

-RRB-

for

supporting

this

research

REFERENCES

AT&T

Clark

K.

B.

Chew

W.

B.

and

Fujimoto

T.

Product

development

in

the

world

auto

industry

Brooking

Papers

on

Economic

Activity

Clark

K.

B.

Chew

W.

B.

and

Fujimoto

T.

Manufacturing

for

design

beyond

the

production/R

D

dichotomy

In

Susman

G.

I.

Integrating

Design

and

Manufacturing

for

Competitive

Advantage

Oxford

University

Press

New

York

Denning

P.

and

Dargan

P.

Action-Centered

Design

In

Winograd

Terry

Bringing

Design

to

Software

ACM

Press

Eudora

Fuks

Hugo

Liker

J.

Fleischer

M.

and

Arnsdorf

D.

Fulfilling

the

Promises

of

CAD

Sloan

Management

Review

Spring

pp.

McDonnell

Douglas

mcdonnell.html

De

Meyer

A.

The

development/manufacturing

interface

empirical

analysis

of

the

European

manufacturing

futures

survey

In

Susman

G.

I.

Integrating

Design

and

Manufacturing

for

Competitive

Advantage

Oxford

University

Press

New

York

National

Semiconductor

semicond.html

Naveiro

R.

M.

and

O?Grady

P.

A

Concurrent

Engineering

Approach

for

Design

Assistance

of

Casting

Parts

In

Proceedings

of

the

International

Conference

on

Engineering

Design

ICED

Praha

Netscape

Navigator

Ohara

M.

CAD/CAM

at

Toyota

Motor

Company

In

Liker

J.

Fleischer

M.

and

Arnsdorf

D.

Fulfilling

the

Promises

of

CAD

Sloan

Management

Review

Spring

pp.

O?Grady

P.

and

Young

R.

Issues

in

Concurrent

Engineering

In

Journal

of

Design

and

Manufacturing

Vol

No.

Chapman

Hall

Great

Britain

pp.

Olivetti

ml

PowWow

Sandia

National

Labs.

sandia.html

Silicon

Graphics

Sproull

L.

and

Kiesler

S.

Connections

news

ways

of

working

in

the

networked

organization

The

MIT

Press

Cambridge

Massachusetts

Ulrich

K.

T.

and

Eppinger

S.

D.

Product

Design

and

Development

McGraw-Hill

New

York

concurrent engineering
digital communication
engineering
manufacturing


Distinguishing Formulas for Free Tiziana Margaria ? Bernhard Steffen Lehrstuhl fur Informatik II RWTH Aachen 5100 Aachen Germany tel : +49 241 8021 .201 fax : +49 241 8021 .229 ftiziana,busg@informatik.rwth-aachen.de Aachener Informatikberichte Nr . 92 -LCB- 23 Abstract A system for the efficient verification of the input/output correctness of Finite State Machines with data path and control unit is presented . This system , which is based on FirstOrder Logic theorem proving , is unique in automatically providing distinguishing formulas expressing all test patterns that witness a behavioural difference between two descriptions . Experimental results illustrate the test pattern generation feature for stuck-at faults , functional faults , and initialization faults , and the efficiency which results from the compositionality of the verification . ? This work has been supported by the Graduiertenkolleg at the RWTH Aachen , Germany . 1 Introduction Traditional symbolic verification methods for Finite State Machines of the complexity of a microprocessor either separately address the data path and the control unit -LRB- eg . -LSB- CMPr91 , NKFT90 , Vemu89 -RSB- -RRB- , or only reduced subsets of Register Transfer level languages -LSB- Fili91 , BEFP89 -RSB- . To extend the verification domain to higher level specifications and to bridge the gap towards high-level testing more flexible approaches are required . In this paper we present a general purpose verification system , which is unique in ffl capturing circuit descriptions that contain both gate level and Register Transfer level primitives , by uniformly interpreting them in terms of First-Order Logic formulas . This will enable us to reduce the proof of input/output correctness to consistency checking in a First-Order Logic , which can be done automatically by means of theorem proving , ffl automatically providing distinguishing formulas expressing all -LRB- sequences of -RRB- input patterns that witness a difference between two descriptions . These formulas , which arise as a byproduct during the verification , allow to generate test patterns in linear-time . The approach addresses a wide class of faults : besides the traditional gate-level stuck-at faults , also faults in the initialization as well as high-level functional faults are considered . Experimental results with the system illustrate the test pattern generation , and the efficiency which results from compositional verification . This allows us to deal with huge Finite State Machines . As an example , the 256-bit counter considered in Section 3 has 2256 ss 1080 states . Our verification system is the only general purpose system that can deal with circuits of that size . Besides yielding efficiency , our approach enables mixed-mode verification , i.e. , each description may contain both behavioural and structural portions . Our verification system is based on OTTER , a resolution-based theorem prover for First-Order Logic with equality -LSB- McCu90 -RSB- . It proves its goal by refutation . Proofs proceed in three steps : first , the semantic expressions for the specification and the implementation are rewritten to yield functions of primary inputs only . Second , they are simplified and canonicalized in a Binary Decision Diagram-like structure -LSB- Brya86 -RSB- . Third , the proof by refutation is executed mainly by rewriting , which guarantees efficiency . Weighting and ordering strategies help choosing the best rewriting strategy , while a user defined lexical ordering on symbols supports the canonicalization of expressions . Related Work : Current hardware verification systems can be classified in ffl very efficient BDD-based special purpose tools , like e.g. the COSMOS symbolic simulator -LSB- Brya89 , FiBr89 -RSB- or the SIAM industrial system -LSB- CoBM89 , MaBi88 -RSB- , which are integrated in the hardware design cycle , but in general capture only a specific abstraction level and/or a specific class of verification problems , and in ffl general purpose tools , including systems based on First-Order Logic , like the Boyer-Moore Prover -LSB- BoMo88 -RSB- or the Larch Prover -LSB- GaGu91 -RSB- which support automatic induction , or on Higher-Order Logics , like e.g. the Nuprl system -LSB- Cons86 -RSB- or the HOL System -LSB- Gord88 -RSB- . These very ambitious tools are tailored for sophisticated reasoning at higher abstraction levels , however they are too inefficient for simpler goals like the ones considered here . Moreover they require extensive user interaction and a deep knowledge of the underlying theory , which restricts the number of possible users . Our system can be regarded as a compromise between the two categories : it is general purpose , e.g. it uniformly captures arbitrary abstraction levels , it naturally supports hierarchical proofs , and it is efficient . Its surprisingly good performance in hardware verification is mainly due to the simple conceptual structure of our system , which offers a variety of optimized basic proof techniques , from which efficient application-specific proof strategies can be built . Moreover , the proofs are completely automatic . Thus the system can directly be used by designers . After presenting the verification framework in Section 2 , Section 3 illustrates the impact of hierarchical verification and the derivation of distinguishing formulas by means of examples . 2 The semantic framework Our notion of correctness of a circuit 's implementation with respect to a specification is based on the following notion of behavioural equivalence , which establishes our specification-implementation relation : Two descriptions D1 and D2 , with boolean primary inputs x = -LRB- x1 ; : : : ; xn -RRB- and y = -LRB- y1 ; : : : ; yn -RRB- , respectively , are called behaviourally equivalent , D1 ssB D2 , iff , starting from equivalent initial states , they produce the same output whenever the input variables are assigned equally . The verification method we propose is based upon the idea that the behavioural equivalence between descriptions can be characterized in a specific derived theory of First Order Logic . This theory is given by the combination of the axiomatizations for the two descriptions , together with the thesis , i.e. a formalization of the claim that both descriptions are behaviourally equivalent . Figure 1 illustrates the verification method . Altogether , verifications in our framework proceed in three steps : i -RRB- axiomatizing the specification and implementation descriptions in First-Order Logic , ii -RRB- enriching the axiomatizations of the two description by adding equations that formalize input/output equivalence , and iii -RRB- computing a normal form of the thesis . Once the semantic extraction criteria have been individuated , the first two steps are simple mappings from the HDL descriptions into the corresponding logic formulas , and are achieved by translation . The third step can then be carried out entirely automatically by means of OTTER . 2.1 Semantic Extraction The semantics of hardware descriptions is given in terms of First-Order theories , i.e. , as axiomatizations in First-Order Logic with equality similarly to -LSB- Evek85 -RSB- . These axiomatizations are composed of an equational characterization of all the HDL language constructs that express the semantics of hardware specific function and predicate symbols , and of some additional equations characterizing the specific properties of the description under consideration . The axiomatization of an HDL consists of an axiomatization of First-Order Logic with equality , together with three sets of equations characterizing the constructs of the gate level , the RT level and the specific HDL -LSB- Marg91 -RSB- : 1 . First-Order Logic with equality : its axiomatization is predefined in OTTER , 2 . gate level semantics : it is defined on the basis of a boolean algebra , a time model , and a substitution mechanism by pattern matching to generate boolean expressions from circuit equations . The access to past values of signals models sequential behaviour -LRB- either Linking the theories Semantics extraction Implementation description in the HDL Specification description in the HDL Semantics extraction Axioms for the HDL constructs Specification in terms of F. O. Logic theories Implementation in terms of F. O. Logic theories the combined F.O. theories Distinguishing formulas Normal Form computation Figure 1 : The verification process asynchronous , as pure before/after relation , or synchronous , with reference to a clocking scheme -RRB- . 3 . RT level semantics : it is defined as a compositional extension of the gate level semantics . To represent registers , memories , and PLA 's , polymorphic list selectors and constructors are introduced . Conditional primitives express control statements . 4 . HDL-specific theories : they are derived by associating a First-Order Logic formula to each language primitive , in order to express its intended semantics in terms of the previously defined set of gate and RT level primitives . The four portions of the axiomatization for an HDL specify the meaning of disjoint sets of constructs . Thus the consistency of the whole axiomatization follows from their individual consistency . This can be proved incrementally . In fact , the consistency of the first three portions has been proved formally once and forever by means of OTTER . We also proved our axiomatization of the RT level subset of VHDL -LSB- SaWa88 -RSB- to be consistent . Of course , our approach can also be applied to other hardware description languages . In particular , in -LSB- Marg91 -RSB- the consistency of the axiomatization of ART ? -LSB- PrGa85 -RSB- , a more expressive Register Transfer level nonprocedural HDL has been shown . The axiomatization of a description consists of additional equations that characterize the behaviour of the corresponding circuit . Each description statement is interpreted as a nested composition of the semantic primitives of the HDL . The resulting equation set consists of boolean operators , list operators , accessors to past values and nested if constructs . This axiomatization can be derived automatically by translation into the logic -LSB- Marg91 -RSB- . Once the logical theories are expressed in terms of the syntax of OTTER , the proof , which only involves the semantic level , can be done entirely automatically . 2.2 The Proof Method In order to establish the link between a pair of theories representing the two descriptions , it suffices to constrain them to share the same input variables and to relate their initial states . The requirement that the desired equivalence relation must then hold for all input configurations -LRB- handled symbolically -RRB- , constitutes the goal -LRB- or thesis -RRB- . Given a circuit with n inputs and m outputs , the axiomatizations of its specification Spec and implementation Impl , and denoting the output functions for the i-th output by OSpeci -LRB- x -RRB- and OImpli -LRB- y -RRB- , the thesis consists of m equations of the form OSpeci -LSB- v = x -RSB- ? OImpli -LSB- v = y -RSB- = where ? denotes the boolean difference function and v is a symbolic input vector . We will abbreviate the i-th boolean difference expression by Ti . This system of equations , which will constitute the set of support for the set of support optimization strategy -LSB- ChLe73 -RSB- , establishes the desired link between the two theories and combines them into a global theory . The thesis defines a rewriting system , when regarded as a set of -LRB- left-to-right -RRB- directed equalities between terms that are Boolean functions represented in if-then-else form . This rewriting system is confluent , and , after limiting the application of the commutative laws with respect to some ordering on the set of symbols , it is also terminating . Thus the following two-steps rewriting process , 1 . all boolean operators are moved top-down on the syntax tree towards the leaves 2 . common subexpressions are then pruned bottom-up , always delivers a unique normal form , which can be automatically transformed in linear time into a Binary Decision Diagram -LRB- BDD -RRB- -LSB- Brya86 -RSB- . Thus we obtain that DSpec ssB DImpl iff Ti is rewritten to for all i : This reduces the verification procedure to the computation of the normal form of for the Ti 's , which can be done efficiently by pure rewriting . In contrast to other hardware verification systems , our system efficiently provides a useful form of diagnostic information without any additional computation effort whenever the specification and the implementation behave differently . Theorem 2.1 -LRB- Distinguishing formulas -RRB- BDD -LRB- Ti -RRB- characterizes the complete set of counterexamples for the input/output equivalence at output i . In particular , it reduces to the single node \ 0 '' iff DSpec ssB DImpl . Since we consider input/output equivalence , and start from an RT level specification but also allow gate level portions in the descriptions , any inconsistency that may arise at the RT -LRB- or gate -RRB- level can be revealed by means of a distinguishing formula . This includes the traditional single stuck-at faults on wires and incorrect initializations , but also more complex faults , like wrong or missing components and incorrect wirings , which are functional faults one would like to detect already at the RT level . The distinguishing information is given in BDD format , whose minimality guarantees : Corollary 2.2 -LRB- Test Pattern Generation -RRB- BDD -LRB- Ti -LRB- v -RRB- -RRB- allows us to obtain each distinguishing pattern in O -LRB- jnj -RRB- time , where n is the number of variables . 3 Application To demonstrate the dramatic impact of hierarchical verification and to illustrate the distinguishing formulas , a counter with enable and synchronous clear has been chosen . The specification defines the behaviour of the circuit in terms of its input/output function . It specifies a control part , which selects one of the four possible operations -LRB- clear , parallel load , increment , no op -RRB- according to the values of the control signals , and a data path consisting of a data register with synchronous clear . The RT level implementation is a cascaded composition of 4-bit modules , each corresponding to a TTL SN74LS163 synchronous up-counter -LRB- see Fig. 2 -RRB- . Its semantic description simply relates the calls to instances of the functional blocks to their -LRB- structural or behavioural -RRB- body . 3.1 Compositional verification The combination of syntactic data abstraction , which avoids slicing , thus simplifying data path expressions , and compositionality in the semantics , which allows a mixed-mode verification , where some structural portions are included at need in a basically behavioural semantics has a dramatic impact on the performance -LRB- -LSB- Marg92 -RSB- -RRB- . This compositional technique for the verification of an implementation wrt . a specification has now been extended to hierarchies of verifications . Considering counters of increasing word size , the impact of structuring RT-level proofs in a hierarchical way is shown by comparing two verification strategies : ffl In a flat strategy , the behavioural description is directly compared with a totally flattened RT-level structural description . Its components are cascaded 4-bit modules , viewed as atomic units . Data-output Data-input enable carry 4-bit-moduleEN TC 4-bit-moduleEN TC 4-bit-moduleEN TC 4-bit-moduleEN TC 8 bit 16 8 8 4 4EN8 4 4 4 TC8TC8 TC16 4 4 8 16 EN8 EN16 4 16 bit 4 4 4 4 8 Figure 2 : Hierarchical implementation of the counter ffl In a hierarchical strategy , the structure of the description is exploited during the proof . Here we consider a hierarchy of 2n-bit counters , each composed of only two instances of an n-bit module , as pictured in Fig. 2 . Results . Fig. 3 illustrates the performances on a SUN SparcStation 1 + with 64 MB memory . They include the cost of the gate level verification of the 4-bit module -LRB- 1.07 s -RRB- , which is negligible for all but the 8-bit counter . The hierarchical approach avoids the exponential blowup in the number of states , and exibits a linear time complexity . This way , a circuit with 2256 ss 1080 reachable states has been verified in a completely symbolic way . In contrast , the flat approach is exponential in the number of modules . Note that most verification tools must follow the flat strategy even for hierarchical designs . 3.2 Distinguishing formulas and Test Pattern Generation The diagnostic capabilities of our system are illustrated wrt . three categories of faults : ffl stuck-at faults on wires , the standard fault model for gate-level testing , ffl functional faults , like the absence or erroneous substitution of a component , and ffl initialization faults , which may be due to incorrect reset conditions . 10 100 1000 10000 100000 time -LRB- s -RRB- flathierarchical 8 16 32 64 128 256 bits Figure 3 : Comparative results In our method , the last two classes of faults can be revealed either directly on the RT level description , or -LRB- more commonly -RRB- on the gate level structural implementation , by comparison with a -LRB- RT or gate level -RRB- description . Thus the test pattern generation becomes fully mixedmode . We apply the method to the 4-bit counter module here . In all three cases we observe the resulting behaviour on the 4-th data output outd -LRB- v -RRB- . Stuck-at faults . Here we assume that the xLoad control input is stuck at 1 in the structural description . Instead of L0 -LRB- x -RRB- = not -LRB- xLoad -RRB- we have now L0 -LRB- x -RRB- = : The distinguishing formula shown in Fig. 4 characterizes in normal form the complete set of test vectors for the fault : every path that leads to 1 in the BDD reveals the difference of the behaviour of the two descriptions at output outd . On the graph , xi indicates the current input value on line i and qi -LRB- t -RRB- = xi -LRB- t ? 1 -RRB- . Note that the signals xClear and xLoad are active low . As an example , the sequence of input patterns -LSB- xClear ; xLoad ; xEnt ; xEnp ; xd ; xc ; xb ; xa -RSB- = < -LSB- ? ; ? ; ? ; ? ; 1 ; 1 ; 1 ; 1 -RSB- ; -LSB- 1 ; ; 1 ; 1 ; 1 ; ? ; ? ; ? -RSB- > corresponding to the highlighted path on the BDD , is a test vector -LRB- of length 2 -RRB- , while < -LSB- 0 ; ? ; ? ; ? ; ? ; ? ; ? ; ? -RSB- > , which corresponds to the path xClear = 0 , executed during the clear operation , is not . Functional faults . The absence of an inverter on the same L0 line can not be handled by standard testing methods . We assume now L0 -LRB- x -RRB- = xLoad . 8 1 1 11 1 1 1 1xD xClear ? Q Q Q Q xD C B A A B 1 C 1 1 1 1 xEnt xEnp QD QD Q 1 Q 1 xLoad Figure 4 : BDD of the distinguishing formula for fault LO01 . The distinguishing formula shown in Fig. 5 characterizes in normal form the complete set of test vectors for this functional fault . It has been obtained in exactly the same way as the formula for the traditional stuck-at fault . As an example , the sequence -LSB- xClear ; xLoad ; xEnt ; xEnp ; xd ; xc ; xb ; xa -RSB- = < -LSB- ? ; ? ; ? ; ? ; 1 ; ? ; ? ; ? -RSB- ; -LSB- 1 ; ? ; ; ? ; ; ? ; ? ; ? -RSB- > is a test pattern of length 2 , and there is no shorter test pattern . 3.2.1 Initialization faults The symbolic state variable QD is initialized to x in the specification , but , erroneously , to its complement in the implementation . Fig. 6 shows that the specification is only met when the initial configuration is overridden via a reset -LRB- clear -RRB- or a preset -LRB- load -RRB- . Reset and preset faults are handled exactly in the same way . 4 Conclusions We have presented a system for the efficient verification of complex FSMs which is based on a compositional semantics encompassing both gate and RT abstraction levels in terms of FirstOrder logic formulas . Our verification methodology efficiently exploits the hierarchy and structural regularity of a design . As a consequence , traditionally exponential problems can be solved in linear time . Moreover , the method automatically provides distinguishing formulas which ex - 9 1xClear 1 1 1 1 1 1 1 1 1 1 1xD xEnt xEnp QD QD Q ? Q Q Q Q xD C B A A B 1 1 Figure 5 : BDD of the distinguishing formula for the functional fault . 1xClear 1 1xLoad Figure 6 : BDD of the distinguishing formula for an initialization fault . press all test patterns that witness a behavioural difference between two descriptions . Besides covering the standard stuck-at faults , the method also addresses functional faults and initialization faults . A parallel implementation of our system , exploiting the independency of outputs , is under development . References -LSB- BEFP89 -RSB- A. Bratsch , H. Eveking et al. : \ LOVERT - A logic verifier of register-transfer level descriptions , '' IMEC-IFIP WG 10.2 / 10.5 Worksh . on \ Applied Formal Methods For Correct VLSI Design '' , Leuven -LRB- Belgium -RRB- , Nov. 1989 , pp. 522-531 . -LSB- Brya86 -RSB- R.E. Bryant : \ Graph-based algorithms for boolean function manipulation , '' IEEE Trans . Computing , vol . C-35 -LRB- 8 -RRB- , August 1986 , pp . 677-691 . -LSB- Brya89 -RSB- R.E. Bryant : \ Verification of synchronous circuits by symbolic logic simulation , '' Worksh . on Hardware Specification , Verification and Synthesis : Mathematical Aspects , LNCS 408 , Springer Verlag , 1989 , pp. 14-24 . -LSB- BoMo88 -RSB- R.S. Boyer , J.S. Moore : \ A Computational Logic Handbook , '' Academic Press , New York , 1988 . -LSB- ChLe73 -RSB- C.L. Chang , R.C. Lee : \ Symbolic logic and mechanical theorem proving , '' Academic Press , Inc. , 1973 . -LSB- CMPr91 -RSB- P.Camurati , T.Margaria , P.Prinetto : \ Formal verification of design correctness of sequential circuits based on theorem provers , '' IEEE CompEuro ' 91 : Advanced Computer Technology , Reliable Systems and Applications , Bologna -LRB- Italy -RRB- , May 1991 , pp. 322-326 . -LSB- CoBM89 -RSB- O. Coudert , C. Berthet , J.C. Madre : \ Verification of synchronous sequential machines based on symbolic execution , '' Workshop on Automatic Verification Methods for Finite State Systems , Grenoble -LRB- France -RRB- , June 1989 . -LSB- Cons86 -RSB- R. L. Constable et al. : \ Implementing Mathematics with the Nuprl Proof Development System , '' Prentice-Hall , Englewood Cliffs , NJ , 1986 . -LSB- Evek85 -RSB- H. Eveking : \ The application of CHDL 's to the abstract specification of hardware , '' IFIP 7th Int . Symp . on Computer Hardware Description Languages and their Applications , Tokyo -LRB- Japan -RRB- , August 1985 , pp. 167-177 . -LSB- FiBr89 -RSB- A.L. Fisher , R.E. Bryant : \ Performance of COSMOS on the IFIP workshop benchmarks , '' IMEC-IFIP WG 10.2 / 10.5 Worksh . on \ Applied Formal Methods For Correct VLSI Design '' , Leuven -LRB- B -RRB- , Nov. 1989 , pp . 595-599 . -LSB- Fili91 -RSB- I. Filippenko : \ VHDL Verification in the State Delta verification System -LRB- SDVS -RRB- , '' Proc . Int . Workshop on Formal Methods in VLSI Design , Miami , FL , -LRB- USA -RRB- , ACM , January 1991 . -LSB- GaGu91 -RSB- S.J. Garland , J.V. Guttag : \ A guide to LP , the Larch Prover , '' Digital Equipment Corp. . Systems Research Center Rep. n. 82 , December 1991 . -LSB- Gord88 -RSB- M. Gordon : \ HOL : a proof generating system for Higher-Order Logic , '' in \ VLSI Specification , Verification and Synthesis '' , G. Birtwistle , P. Subrahmanyam eds. , Kluwer , 1988 . -LSB- Lang90 -RSB- M. Langevin : \ Automated RTL verification based on predicate calculus , '' Int . Worksh . on \ Computer-Aided Verification '' , DIMACS Series in Discrete Mathematics and Th . Computer Science , AMS , 1990 , pp. 577-590 . -LSB- MaBi88 -RSB- J.C. Madre , J.P. Billon : \ Proving circuit correctness using formal comparison between expected and extracted behaviour , '' DAC-25 : 25th ACM/IEEE Design Automation Conference , Anaheim , CA -LRB- USA -RRB- , June 1988 , pp. 211-217 . -LSB- Marg91 -RSB- T. Margaria : \ First-Order theories for the verification of complex FSMs , '' Aachener Informatik-Berichte Nr.91-30 , RWTH-Aachen , Dec. 1991 . -LSB- Marg92 -RSB- T. Margaria : \ Efficient RT-Level Verification by Theorem Proving '' , IFIP World Congr . ' 92 , Madrid -LRB- Spain -RRB- , Sept. 1992 , North-Holland pp. 696-702 . -LSB- McCu90 -RSB- W.W. McCune : \ OTTER 2.0 User 's Guide , '' Rep. ANL-90 / 9 Mathematics and Computer Science Division , Argonne Nat . Lab. , Argonne , IL -LRB- USA -RRB- . -LSB- NKFT90 -RSB- H. Nakamura , Y. Kukimoto , M. Fujita , H. Tanaka : \ A data path verifier for Register Transfer level using Temporal Logic language TOKIO , '' Int . Workshop on \ Computer-Aided Verification '' , DIMACS Series in Discrete Mathematics and Th . Computer Science , Vol .3 , AMS , 1990 , pp. 493-504 . -LSB- PrGa85 -RSB- P.Prinetto , S. Gai : \ ART ? : user manual , '' Int . Rep. DAI/CAD n. 14/85 , Dipartimento di Automatica e Informatica , Politecnico di Torino , Torino -LRB- Italy -RRB- , October 1985 . -LSB- SaWa88 -RSB- \ IEEE Standard VHDL Reference Manual , '' L. Saunders , R. Waxman eds. , IEEE , 1988 . -LSB- Vemu89 -RSB- R. Vemuri : \ A formal model for Register-Transfer level structures and its applications in verification and synthesis , '' IMEC-IFIP Workshop on \ Applied Formal Methods For Correct VLSI Design '' , Leuven -LRB- Belgium -RRB- , November 1989 , Vol . 2 , pp. 77-96 .

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O

high level design tools - design verification