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Requirements Engineering:
Introduction
�W
hy R
E?
�S
oftw
are
Life
cycl
e an
d E
rror
Pro
paga
tion
�C
ase
Stu
dies
and
The
Sta
ndis
h R
epor
t
�W
hat i
s R
E?
�R
ole
of R
equi
rem
ents
�R
oss’
s D
efin
ition
of R
equi
rem
ents
Def
initi
on�
The
Ref
eren
ce M
odel
(W
RS
PM
) vs
. The
4-V
aria
ble
Mod
el�
Zav
e’s
Def
initi
on o
f RE
�H
ow to
do
RE
?�
Type
s of
Err
ors
�D
esira
ble
Pro
pert
ies
10. O
ther
9. R
elia
ble
Est
imat
es
8. F
orm
al M
eth
od
olo
gy
7. Firm Basic Requirements
Firm Basic Requirements
Firm Basic Requirements
Firm Basic Requirements
6. S
tand
ard
Sof
twar
e In
fras
truc
ture
5. Minimized Scope
Minimized Scope
Minimized Scope
Minimized Scope
4. Clear Business Objectives
Clear Business Objectives
Clear Business Objectives
Clear Business Objectives
3. E
xper
ienc
ed P
roje
ct M
anag
er
2. User Involvement
User Involvement
User Involvement
User Involvement
1. E
xecu
tive
Man
agem
ent S
uppo
rt
Pro
ject
Suc
cess
Fac
tors
The Standish Group Report, ‘01 –The “Chaos” Report (www.standishgroup.com), yearly since 1994
28%
28%
28%
28%
49%
49%
49%
49%
23%
23%
23%
23%
com
plet
ed o
n tim
e an
d on
bud
get
canc
eled
bef
ore
com
plet
ion
over
ran
orig
inal
est
imat
es
-Tim
e ov
erru
n av
erag
ed 6
3%-
Cos
t ove
rrun
ave
rage
d 45
%
Issues
137,000 projects
65,000 projects
78,000 projects
The CHAOS
CHAOS Ten
Wha
t Fac
tors
Con
trib
ute
to P
roje
ct S
ucce
ss?
Wha
t Fac
tors
Con
trib
ute
to P
roje
ct F
ailu
re?
Sta
ndis
h G
roup
, ‘01
(w
ww
.sta
ndis
hgro
up.c
om)
The
CH
AO
S
CH
AO
S T
enT
he C
HA
OS
C
HA
OS
Ten
“The definition of insanity is doing the same thing over and over
again and expecting a different result.” [Albert Einstein]
Issues
Siz
e Is
Impo
rtan
t: S
ucce
ss b
y P
roje
ct S
ize
0102030405060
Pro
ject
Siz
e ($
)
less
than
$75
0K
$750
K to
$1.
5M
$1.5
M to
$3M
$3M
to $
6M
$6M
to $
10M
Ove
r $1
0M
Suc
cess
R
ate
(%)
Sta
ndis
h G
roup
, ‘99
(w
ww
.sta
ndis
hgro
up.c
om)
Why?
Why?
Why?
Why?
The
Hig
h C
ost o
f Req
uire
men
t Err
ors
Rel
ativ
e co
st to
rep
air
erro
rs:
Whe
n in
trod
uced
vs.
whe
n re
paire
d.
100
2.5 5 10 25.5
-1
Req
uire
men
ts T
ime
Des
ign
Cod
ing
Uni
t Tes
t
Acc
epta
nce
Test
Mai
nten
ance
“All
toge
ther
, the
res
ults
sh
ow a
s m
uch
as a
200
:1
cost
ratio
bet
wee
n fin
ding
err
ors
in th
e re
quire
men
ts a
nd
mai
nten
ance
sta
ges
of
the
softw
are
lifec
ycle
.”
[Boe
hm 1
988]
Ave
rage
cos
t rat
io 1
4:1
[Gra
dy19
89]
Th
e 1-
10-1
00 R
ule
[Dav
is 1
993]
com
ple
te &
so
un
d I/
Oco
mp
lexi
ty in
th
e #
of
I/O it
ems,
an
d r
elat
ion
ship
s b
etw
een
them
and
co
nst
rain
ts o
n th
em
shou
ld b
e w
ritte
n in
the
user
’s la
ngua
ge!
We
wan
t to
mak
e a
chan
ge in
the
envi
ronm
ent
We
will
bui
ld s
ome
syst
em t
o do
itT
his
syst
em m
ust i
nter
act
with
the
envi
ronm
ent
No
tab
ou
t th
e d
esig
n
Fn
NFn
E/D/B/W
E/D/B/W
E/D/B/W
E/D/B/W
R RRR S SSS
trad
itio
nal
em
ph
asis
her
e o
r in
S +
D
why?
what?
how?
Fn
NFn
E/D/B/W
E/D/B/W
E/D/B/W
E/D/B/W
R RRR S SSStr
adit
ion
al e
mp
has
is h
ere
or
in S
+ D
Wha
t are
req
uire
men
ts?
[P. Z
ave
and
M. J
acks
on,
Fou
r D
ark
Cor
ners
of
Req
uire
men
ts E
ngin
eerin
g. A
CM
Tra
nsac
tions
on
Sof
twar
e E
ngin
eerin
g an
d M
etho
dolo
gy6(
1) 1
-30.
AC
M P
ress
. 19
97]
D –
Dom
ain
Pro
pert
ies
(wo
rld
, en
terp
rise
, bu
sin
ess,
do
mai
n t
heo
ry)
R -
Req
uire
men
tsS
-S
peci
ficat
ion
C –
Com
pute
r
P -
Pro
gram
phen
omen
a/th
ings
not
obs
erva
ble
by m
achi
ne (
e h)
phen
omen
a/th
ings
not
obs
erva
ble
by d
omai
n (s
h)
phen
omen
a/sh
ared
thi
ngs
�do
mai
n-co
ntro
lled
(ev)
�m
achi
ne-c
ontr
olle
d (s
v)
�D
omai
n P
rope
rtie
s:
(indi
cativ
e, =
ass
umpt
ions
=dom
ain
know
ledg
e)
thin
gs in
the
envi
ronm
ent (
appl
icat
ion
dom
ain)
that
are
true
reg
ardl
ess
of th
e pr
opos
ed s
yste
m
�R
equi
rem
ents
: (o
ptat
ive)
thin
gs in
the
appl
icat
ion
dom
ain
that
we
wis
h to
be
mad
e tr
ue th
roug
h th
e pr
opos
ed s
yste
m“Many phenomena not accessible by the machine”
“Many phenomena not accessible by the machine”
“Many phenomena not accessible by the machine”
“Many phenomena not accessible by the machine”
�S
peci
ficat
ion:
a de
scrip
tion
of th
e be
havi
ors
that
the
prog
ram
mus
t hav
e in
ord
er to
mee
t the
req
uire
men
ts"Can, and should, only be written in terms of shared phenomena”
"Can, and should, only be written in terms of shared phenomena”
"Can, and should, only be written in terms of shared phenomena”
"Can, and should, only be written in terms of shared phenomena”
�Designated Terminology –
nam
es/v
oca
bu
lary
to
des
crib
e W
, (R
), S
, M in
ter
ms
of
ph
eno
ma
–ty
pic
ally
sta
tes
or
even
ts
The
WR
SP
M M
odel
s =
sv
e ∩
s =
Φe h∩
ev
= Φ
s v∩
sh
= Φ
[C. G
unte
r, E
. G
unte
r, M
. Jac
kson
and
P. Z
ave,
“A
Ref
eren
ce M
odel
for
Req
uire
men
ts a
nd S
peci
ficat
ions
,” I
EE
E S
oftw
are,
May
/Jun
e 20
00.
pp.
37-4
3]
�R RRR
equi
rem
ents
des
crib
e w
hat
is o
bser
vabl
e at
the
inte
rfac
e be
twee
n th
e en
viro
nmen
t an
d th
e m
achi
ne –
henc
e ex
ist
only
in th
e e eee
nviro
nmen
t;
�A
nyth
ing
else
is r
egar
ded
as i iii
mpl
emen
tatio
n bi
as;
�S
tate
s in
s ssspe
cific
atio
ns s
houl
d de
scrib
e st
ates
of t
he e eee
nviro
nmen
t –he
nce,
spe
cific
atio
n la
ngua
ges
inte
nded
to
desc
ribe
inte
rnal
(pr
ogra
m)
stat
es o
f the
mac
hine
are
inad
equa
te.
Con
sequ
ence
s�
Fre
edom
to
colle
ct a
nd r
ecor
d in
form
atio
n ab
out t
he e eee
nviro
nmen
t eve
n be
fore
we
are
sure
it w
ill b
e ne
eded
(i.e
., n
o m
inim
alit
y re
stri
ctio
n -
ther
e m
ust
be
no
thin
g th
at is
no
t n
eces
sary
to
car
ry o
ut t
he
curr
entl
y p
rop
ose
d m
ach
ine
fun
ctio
ns.
);
�D
esig
natio
ns r
efer
to th
e re
al w www
orld
, and
m mmmac
hine
sta
tes
may
hav
e N
O d
irect
cor
resp
onde
nce
to it
[P. Z
ave
and
M. J
acks
on,
Fou
r D
ark
Cor
ners
of
Req
uire
men
ts E
ngin
eerin
g. A
CM
Tra
nsac
tions
on
Sof
twar
e E
ngin
eerin
g an
d M
etho
dolo
gy6(
1) 1
-30.
AC
M P
ress
. 19
97]
D –
Dom
ain
Pro
pert
ies
(Wo
rld
, En
terp
rise
, Bu
sin
ess,
Do
mai
n t
heo
ry)
R -
Req
uire
men
ts
S S S S - ---Specification
Specification
Specification
Specification
C –
Com
pute
r
P -
Pro
gram
ph
eno
men
a/th
ing
s n
ot
ob
serv
able
by
mac
hin
e (e
h)
ph
eno
ma/
thin
gs
no
t o
bse
rvab
le b
y d
om
ain
(s h
)sh
ared
ph
eno
man
a/th
ing
s�
do
mai
n-c
on
tro
lled
(e v
)
�m
ach
ine-
con
tro
lled
(s v
)
The
WR
SP
M M
odel
P, C |= S
Requirements should contain
Requirements should contain
Requirements should contain
Requirements should contain nothing but
nothing but
nothing but
nothing but information about the environment.
information about the environment.
information about the environment.
information about the environment.
W, R RRR
-us
es {
e h, e
v, s
v}P
, M-
uses
{e v
, sv,
sh}
S-
uses
{e v
, sv}
indi
cativ
eop
tativ
ee h
��
e v�
�
s v�
�
Wha
t are
req
uire
men
ts?
D1:
The
re w
ill a
lway
s be
a n
urse
clo
se e
noug
h to
he
ar th
e bu
zzer
D2:
The
sou
nd fr
om th
e he
art f
allin
g be
low
a
cert
ain
thre
shol
d in
dica
tes
that
hea
rt h
as
(is a
bout
to)
stop
R1:
A w
arni
ng s
yste
m n
otifi
es th
e nu
rse
if th
e pa
tient
’s h
eart
beat
sto
ps
S1:
If th
e so
und
from
the
sens
or fa
lls
belo
w a
cer
tain
thre
shol
d, t
hebu
zzer
sha
ll be
act
uate
d
C –
with
a m
icro
phon
e as
a s
enso
r an
d a
buzz
er a
s an
act
uato
r
P -
Pro
gram
Exa
mpl
e 1:
Pat
ient
Mon
itorin
g
Wh
at if
th
e d
om
ain
ass
um
pti
on
s ar
e w
ron
g?
a-fib
.com
[C. G
unte
r, E
. G
unte
r, M
. Jac
kson
and
P. Z
ave,
“A
Ref
eren
ce M
odel
for
Req
uire
men
ts a
nd S
peci
ficat
ions
,” I
EE
E S
oftw
are,
May
/Jun
e 20
00.
pp.
37-4
3]
Des
ign
atio
n C
ateg
ori
es:
e h: t
he n
urse
and
the
hear
tbea
t of t
he p
atie
nt.
e v: s
ound
s fr
om th
e pa
tient
’s c
hest
.s v
: the
buz
zer
at th
e nu
rse’
s st
atio
n.s h
: int
erna
l rep
rese
ntat
ion
of d
ata
from
the
sens
or.
Wha
t are
req
uire
men
ts?
D1:
Driv
ers
stop
at r
ed li
ghts
D2:
Ped
estr
ians
wal
k w
hen
gree
n
R1:
Allo
w p
edes
tria
ns t
o cr
oss
the
road
saf
ely
S1:
Sho
w a
red
ligh
t to
the
cars
and
a gr
een
light
to th
e pe
dest
rians
C –
Com
pute
r
P -
Pro
gram
Exa
mpl
e 2:
Tra
ffic
light
s
Exa
mpl
e 3:
Tra
ffic
Ligh
ts -
Saf
ety
Wh
at if
th
e d
om
ain
ass
um
pti
on
s ar
e w
ron
g?
D1.
Driv
ers
stop
at r
ed li
ghts
D2.
Ped
estr
ians
sto
p at
red
ligh
tsD
3. D
river
s dr
ive
at g
reen
ligh
tsD
4. P
edes
tria
ns w
alk
whe
n gr
een
R1:
Ped
estr
ians
and
car
s ca
nnot
be
inth
e in
ters
ectio
n at
the
sam
e tim
e
S1:
Nev
er s
how
a g
reen
ligh
t to
both
ped
estr
ians
and
car
s
C –
Com
pute
r
P -
Pro
gram
ww
w.s
crgo
lf.co
m
Wha
t are
req
uire
men
ts?
D1:
Whe
el p
ulse
s on
if a
nd o
nly
if w
heel
s tu
rnin
gD
2: W
heel
s tu
rnin
g if
and
only
if m
ovin
g on
run
way
R1:
Rev
erse
thr
ust s
hall
only
be
enab
led
whe
n th
e ai
rcra
ft is
mov
ing
on th
e ru
nway
S1:
Rev
erse
thru
st e
nabl
ed
if an
d on
ly if
whe
el p
ulse
s on
C –
Com
pute
r
P -
Pro
gram
Exa
mpl
e 4:
Airc
raft
Con
trol
Exa
mpl
e 5:
Sec
urity
Wh
at if
th
e d
om
ain
ass
um
pti
on
s ar
e w
ron
g?
D1:
Aut
horiz
ed p
erso
nnel
hav
e pa
ssw
ords
D2:
Pas
swor
ds a
re n
ever
sha
red
with
no
n-au
thor
ized
per
sonn
el
R1:
The
dat
abas
e sh
all o
nly
be a
cces
sibl
e by
au
thor
ized
per
sonn
el
S1:
Acc
ess
to th
e da
taba
se s
hall
only
be
gra
nted
afte
r th
e us
er ty
pes
an
auth
oriz
ed p
assw
ord
C –
Com
pute
r
P -
Pro
gram
hom
epag
e.nt
lwor
ld.c
om
Wha
t are
req
uire
men
ts?
D1:
Bef
ore
the
switc
h is
mov
ed to
the
On
posi
tion,
th
e us
er m
ust
add
grou
nd c
offe
e to
the
filte
r an
d in
sert
it in
the
coffe
e m
achi
ne.
D2:
Bef
ore
the
switc
h is
mov
ed to
the
On
posi
tion,
th
e us
er m
ust
add
wat
er to
the
rese
rvoi
r.
R1:
Whe
n th
e us
er m
oves
the
thre
e-w
ay s
witc
h to
the
On
posi
tion,
cof
fee
shal
l be
brew
ed.
S1:
If th
e th
ree-
way
sw
itch
is O
n,
the
coffe
e br
ewer
sha
ll be
act
uate
d
C –
with
a s
witc
h as
a s
enso
r an
d a
brew
er a
s an
act
uato
r
P -
Pro
gram
Exa
mpl
e 6:
Cof
fee
Mac
hine
Des
ign
atio
n C
ateg
ori
es:
e h: ?
e v: ?
s v: ?
s h: ?
•de
posi
t(a,
m):
ais
an
actio
n in
whi
ch a
mou
nt m
is d
epos
ited
•w
ithdr
awal
-req
uest
(a,m
):a
is a
n ac
tion
in w
hich
a w
ithdr
awal
of a
mou
nt m
is r
eque
sted
•w
ithdr
awal
-pay
out(
a,m
):a
is a
n ac
tion
in w
hich
am
ount
mis
pai
d ou
t as
a w
ithdr
awal
•ba
lanc
e(b,
p):
durin
g pa
use
pth
e ba
lanc
e is
am
ount
b;
At a
ny t
ime,
the
bala
nce
is e
qual
to th
e su
m o
f the
am
ount
s of
all
the
prev
ious
dep
osits
, m
inus
the
sum
of t
he a
mou
nts
of a
ll th
e pr
evio
us w
ithdr
awal
pay
outs
:
Wha
t Are
Req
uire
men
ts?
D Exa
mpl
e 7:
In a
sin
gle-
cust
omer
ban
king
env
ironm
ent,
�N
otat
ion:
equ
atio
nal
logi
c
�ac
tion(
a):
atom
ic a
nd s
eque
ntia
l;
�ea
rlier
(a1,
a2)
:a
nond
ense
tot
al o
rder
on
actio
ns;
�pa
use(
p):
a un
ique
pau
se b
etw
een
each
adj
acen
t pa
ir of
act
ions
�be
gins
(a,p
):ac
tion
apr
eced
es p
ause
pim
med
iate
ly in
the
tem
pora
l seq
uenc
e
�en
ds(a
,p):
actio
n a
succ
eeds
pau
se p
imm
edia
tely
in th
e te
mpo
ral s
eque
nce
�(*
i |
R(i)
: P
(i)):
the
accu
mul
atio
n of
val
ues
P(i)
, usi
ng o
pera
tor
*,
over
all
valu
es i
for
whi
ch p
redi
cate
R(i)
hol
ds.
R
A w
ithdr
awal
req
uest
lead
s to
a w
ithdr
awal
pay
out,
if th
e re
ques
ted
amou
nt is
less
then
the
curr
ent
bala
nce
S–
a re
quire
men
t (R
), w
hich
is im
plem
enta
ble,
hen
ce a
spe
cific
atio
n
The 4
The 4
The 4
The 4- ---Variable Model
Variable Model
Variable Model
Variable Model
Environment
Inpu
tD
evic
esO
utpu
tD
evic
esEnvironment
Software
Mon
itore
dva
riabl
esC
ontr
olle
dva
riabl
esin
put
data
outp
utda
ta
syst
em
S -
Spe
cific
atio
n of
sof
twar
e in
term
s of
inpu
ts &
out
puts
(p
oss
ibly
larg
e in
nu
mb
er, a
nd
in v
ery
com
ple
x re
lati
on
ship
s)
NAT
(m, c
):de
scrib
es n
atur
e w
ithou
t mak
ing
any
assu
mpt
ions
abo
ut th
e sy
stem
;
RE
Q(m
, c):
desc
ribes
the
desi
red
syst
em b
ehav
ior;
IN(m
, i):
rela
tes
the
mon
itore
d re
al-w
orld
val
ues
to th
eir c
orre
spon
ding
inte
rnal
repr
esen
tatio
n;
OU
T(o
, c):
rela
tes
the
softw
are-
gene
rate
d ou
tput
s to
ext
erna
l sys
tem
-con
trol
led
valu
es; a
nd
SO
F(i,
o):
rela
tes
prog
ram
inpu
ts to
pro
gram
out
puts
.
(the
func
tiona
l doc
umen
tatio
n m
odel
)
Any issues?
Any issues?
Any issues?
Any issues?
Nat
-th
e ra
nge
of s
ound
s de
tect
ed o
r no
n-de
tect
ed b
y th
e se
nsor
and
the
pos
sibl
e ra
nge
of v
alue
s of
the
act
uato
r co
ntro
lling
the
buz
zer.
Req
-A w
arni
ng t
hat
notif
ies
the
nurs
e if
the
syst
em d
etec
ts h
eart
sto
ps b
eatin
g. T
he d
ocum
ent’
form
aliz
atio
n: if
the
soun
d be
ing
mon
itore
d
falls
bel
ow a
cer
tain
thr
esho
ld,
then
the
sys
tem
sou
nd t
he b
uzze
r.
In -
The
inpu
t re
gist
ers
hold
ing
the
data
rea
d fr
om t
he s
enso
r m
onito
ring
the
soun
ds o
f th
e he
art
beat
.
Ou
t-
The
out
put
regi
ster
s w
hich
are
rea
d by
the
actu
ator
tha
t ca
n so
und
the
buzz
er.
SO
F-
If th
e in
put
regi
ster
doe
sn't
show
sig
ns o
f a
hear
t be
at f
or m
ore
than
som
e sp
ecifi
ed t
ime
then
the
out
put
regi
ster
indi
cate
sth
e al
arm
to r
ing.
a-fib
.com
D.L
. Par
nas
and
J. M
adey
, “F
unct
iona
l Doc
umen
tatio
n fo
r C
ompu
ter
Sys
tem
s,”
Sci
ence
of C
ompu
ter
Pro
gram
min
g, V
ol.
25,
No.
1, O
ct.
1995
, pp
. 41
–61.
Bou
ndar
ies
are
not f
ixed
peop
le w
aitin
g
peop
le in
the
elev
ator
peop
le w
antin
g to
go
to a
par
ticul
ar fl
oor
elev
ator
mot
ors
safe
ty r
ules
elev
ator
cal
l but
tons
floor
req
uest
but
tons
curr
ent f
loor
indi
cato
rsm
otor
on/
off
door
ope
n/cl
ose
sche
dulin
g al
gorit
hm
cont
rol p
rogr
am
thin
gs n
ot o
bser
vabl
e by
mac
hine
thin
gs n
ot o
bser
vabl
e by
dom
ain
shar
ed th
ings
�do
mai
n-co
ntro
lled
�M
achi
ne-c
ontr
olle
d
Exa
mpl
e 1:
Ele
vato
r co
ntro
l sys
tem
E.g
. Ad
d s
om
e se
nso
rs to
det
ect w
hen
peo
ple
are
wai
ting
Th
is c
han
ges
the
nat
ure
of t
he
pro
ble
m to
be
solv
ed
Exa
mpl
e 2:
The
4-v
aria
ble
mod
el
Environment
Inpu
tD
evic
esO
utpu
tD
evic
esEnvironment
Software
Mon
itore
dva
riabl
esC
ontr
olle
dva
riabl
esin
put
data
outp
utda
ta
syst
em
S -
Spe
cific
atio
n of
sof
twar
e in
term
s of
inpu
ts &
out
puts
(p
oss
ibly
larg
e in
nu
mb
er, a
nd
in v
ery
com
ple
x re
lati
on
ship
s)
Sys
tem
s en
gine
er
deci
des
-w
hat
appl
icat
ion
dom
ain
phen
omen
a ar
e sh
ared
-th
e bo
unda
ries
by d
esig
ning
the
inpu
t/out
put
devi
ces
-I/O
dat
a as
pro
xies
for
the
mon
itore
d an
d co
ntro
lled
varia
bles
ww
w.g
eoci
ties.
com
Ano
ther
Loo
k at
Com
plet
enes
s[p
. Zav
e an
d M
. Jac
kson
, Fou
r D
ark
Cor
ners
of R
equi
rem
ents
Eng
inee
ring.
AC
M
Tra
nsac
tions
on
Sof
twar
e E
ngin
eerin
g an
d M
etho
dolo
gy6(
1) 1
-30.
AC
M P
ress
. 199
7.
If th
e fiv
e fo
llow
ing
crite
ria a
re s
atis
fied,
then
re
quire
men
ts e
ngin
eerin
g, in
the
stro
nges
t sen
se, i
s co
mpl
ete.
… r
equi
rem
ents
sho
uld
cont
ain
noth
ing
but i
nfor
mat
ion
abou
t the
env
ironm
ent.
[p9]
Th
e re
qu
irem
ents
are
co
mp
lete
if t
hey
are
su
ffic
ien
t to
est
ablis
h t
he goal
goal
goal
goal
they
are
ref
inin
g[K
. Yue
, “W
hat
Doe
s It
Mea
n to
Say
tha
t a S
peci
ficat
ion
is C
ompl
ete?
’, P
roc.
IWS
SD
-4,
Fou
rth
Inte
rnat
iona
l Wor
ksho
p on
Sof
twar
e S
peci
ficat
ion
and
Des
ign,
Mon
tere
y, 1
987.
]
R:
a m
odel
of
the
requ
irem
ents
D:
a m
odel
of
the
envi
ronm
ent
S:
a m
odel
of
the
sw b
ehav
ior
satis
fy
acts upon
constrains
Fn
NFn
E/D/B/W
E/D/B/W
E/D/B/W
E/D/B/W
R RRR S SSS
goal
serv
ices
cons
trai
nts
spec
ifica
tions
relationships
evol
utio
n
M MMMG GGG, Prog
Prog
Prog
ProgG GGG|= S SSS
G GGG; S SSSG GGG, D DDDG GGG|= R RRR
G GGG; R RRRG GGG, D DDDG GGG|= G GGG; (G GGG|= ¬ ¬¬¬P PPP) V (G GGG|~ ¬ ¬¬¬P PPP)
R:
a m
odel
of
the
requ
irem
ents
D:
a m
odel
of
the
envi
ronm
ent
S:
a m
odel
of
the
sw b
ehav
ior
satis
fy
acts upon
constrains
G: g
oals
FnNFn
W WWW R RRR S SSS
M MMMG GGG, Prog
Prog
Prog
ProgG GGG|= S SSS
G GGG; S SSSG GGG, D DDDG GGG|= R RRR
G GGG; R RRRG GGG, D DDDG GGG|= G GGG; (G GGG|= ¬ ¬¬¬P PPP) V (G GGG|~ ¬ ¬¬¬P PPP)
softgoal satisficing
softgoal satisficing
softgoal satisficing
softgoal satisficing
ref -
IEE
E 8
30
“A s
hall
do B
to C
”
“A s
hall
do B
to C
”
“A s
hall
do B
to C
”
Qua
litie
s of
a R
equi
rem
ent:
Una
mbi
guou
s
•A
req
uire
men
t is
unam
bigu
ous
if it
has
only
one
inte
rpre
tati
on
.
Exp
lore
Am
bigu
ity: D
ictio
nary
Def
initi
ons
had
-P
ast o
f hav
e
hav
e-
1a: T
o ho
ld in
pos
sess
ion
as p
rope
rty
4a: T
o ac
quire
or
get p
osse
ssio
n of
: O
BT
AIN
(be
st to
be
had)
4c:
AC
CE
PT
; to
hav
e in
mar
riage
5a:
To
be m
arke
d or
cha
ract
eriz
ed b
y (h
ave
red
hair)
10a:
To
hold
in a
pos
ition
of d
isad
vant
age
or c
erta
in d
efea
t 10
b: T
RIC
K, F
OO
L (b
een
had
by a
par
tner
)12
: B
EG
ET
, BE
AR
(ha
ve a
bab
y)13
: T
o pa
rtak
e of
(ha
ve d
inne
r)14
: B
RIB
E, S
UB
OR
N (
can
be h
ad fo
r a
pric
e)
lam
b-
1a:
A y
oung
she
ep e
sp. l
ess
than
one
yea
r ol
d or
with
out
perm
anen
t tee
th1b
: T
he y
oung
of v
ario
us o
ther
ani
mal
s (a
s sm
alle
r an
telo
pes)
2a:
A p
erso
n as
gen
tle o
r w
eak
as a
lam
b2b
: D
EA
R, P
ET
2c:
A p
erso
n ea
sily
che
ated
or
dece
ived
esp
ecia
lly in
trad
ing
secu
ritie
s3a
: T
he fl
esh
of la
mb
used
as
food
Mar
y h
ad a
litt
le la
mb
.
Exp
lore
Am
bigu
ity: A
naly
sis
Hav
eLa
mb
Inte
rpre
tatio
n1a
1aM
ary
owne
d a
little
she
ep u
nder
one
yea
r of
age
or
with
out p
erm
anen
t tee
th.
4a1a
Mar
y ac
quire
d a
little
she
ep u
nder
one
yea
r of
age
or
with
out p
erm
anen
t tee
th.
5a1a
Mar
y is
the
pers
on w
ho o
wne
d a
little
she
ep u
nder
on
e ye
ar o
f age
or
with
out p
erm
anen
t tee
th.
10a
1aM
ary
held
a li
ttle
shee
p un
der
one
year
of a
ge o
r w
ithou
t per
man
ent t
eeth
in a
pos
ition
of d
isad
vant
age.
10b
1aM
ary
tric
ked
a lit
tle s
heep
und
er o
ne y
ear
of a
ge o
r w
ithou
t per
man
ent t
eeth
.12
1bM
ary
gave
birt
h to
a y
oung
ant
elop
e.
122a
Mar
y is
(or
was
) th
e m
othe
r of
a p
artic
ular
sm
all,
gent
le
pers
on.
133a
Mar
y at
e a
little
of t
he fl
esh
of la
mb.
142c
Mar
y br
ibed
a s
mal
l per
son
trad
ing
in s
ecur
ities
who
w
as e
asily
che
ated
.
Exp
lore
Am
bigu
ity: A
n O
bser
vatio
n
Und
erst
anda
bilit
y
Am
bigu
ity
The
sw
eet s
pot
Qua
litie
s of
Sof
twar
e R
equi
rem
ents
•C
orre
ct–
Is a
true
sta
tem
ent o
f som
ethi
ng th
e sy
stem
mus
t do.
•C
ompl
ete
–D
escr
ibes
all
sign
ifica
nt re
quire
men
ts o
f con
cern
to th
e us
er.
•C
onsi
sten
t–
Doe
s no
t con
flict
with
oth
er r
equi
rem
ents
.•
Una
mbi
guou
s–
Is s
ubje
ct to
one
and
onl
y on
e in
terp
reta
tion.
[Lef
fingw
ell &
Wid
rig (1
999)
. IE
EE
830
-199
3, §
4.3.
2, 1
994]
•V
erifi
able
–C
an b
e te
sted
cos
t effe
ctiv
ely.
•R
anke
d fo
r im
port
ance
and
sta
bilit
y–
Can
be
sort
ed b
ased
on
cust
omer
impo
rtan
ce a
nd s
tabi
lity
of th
e re
quire
men
t its
elf.
•M
odifi
able
–C
hang
es d
o no
t affe
ct th
e st
ruct
ure
and
styl
e of
the
set.
•Tr
acea
ble
–T
he o
rigin
of e
ach
requ
irem
ent c
an b
e fo
und.
•U
nder
stan
dabl
e–
Com
preh
ende
d by
use
rs a
nd d
evel
oper
s.
IEE
E 8
30-1
993,
§4.
3.2,
199
4
-T
he s
yste
m s
uppo
rts
up to
1,0
00 s
imul
tane
ous
user
s.-T
he s
yste
m s
hall
resp
ond
to a
n ar
bitr
ary
quer
y in
500
mse
c.-T
he c
olor
sha
ll be
a p
leas
ing
shad
e of
gre
en.
-The
sys
tem
sha
ll be
ava
ilabl
e 24
x 7
.-T
he s
yste
m s
hall
expo
rt v
iew
dat
a in
com
ma-
sepa
rate
d fo
rmat
,ac
cord
ing
to th
e IE
EE
spe
cific
atio
n.
Qua
litie
s of
a R
equi
rem
ent:
Ver
ifiab
le
•A
req
uire
men
t is
verif
iabl
e if:
–T
here
exi
sts
som
e fin
ite, c
ost-
effe
ctiv
e pr
oces
s w
ith w
hich
a p
erso
n or
m
achi
ne c
an c
heck
that
the
prod
uct m
eets
the
requ
irem
ent.
Are
thes
e re
quire
men
ts v
erifi
able
? If
not,
wha
t is
a be
tter
way
to
stat
e th
em?
Par
ts o
f Lec
ture
Not
es C
ome
Fro
mS
ome
basi
c m
ater
ial
Intr
oduc
tion
to R
E[D
avi
s.C
h1;
LK
.Ch
1]R
equi
rem
ents
En
gin
eeri
ng
Pro
cess
es[L
K.C
h2]
RE
evo
lutio
nary
pro
cess
RE
bas
ic p
roce
ssR
E in
sof
twar
e lif
ecyc
leP
roce
ss v
s. p
rodu
ct s
peci
ficat
ions
Req
uire
men
ts A
na
lysi
s, M
odel
ing
an
d S
peci
fica
tion
[LK
.Sec
4.1
-4.2
]R
equi
rem
ents
Elic
itatio
n:
[LK
.Ch
3]S
cen
ari
o A
na
lysi
s [M
art
in &
Ode
ll. C
h28
]E
nte
rpri
se R
equi
rem
ents
: [L
K.S
ec4.
3]M
odel
ing
Tec
hn
ique
sA
gen
t-or
ien
ted
ente
rpri
se m
odel
ing
Bus
ines
s m
odel
ing
with
UM
L[L
effin
gwel
l and
Eid
rig, 2
003]
Con
ven
tion
al e
nte
rpri
se m
odel
ing
tech
niq
ues}
AS
-IS
or
TO
-BE
?F
unct
ion
al R
equi
rem
ents
: Sem
i-fo
rma
l Str
uctu
ral M
odel
s [L
K.S
ec4.
3; D
avi
s.C
h2]
Str
uctu
red
an
aly
sis
Fun
ctio
na
l Req
uire
men
ts: F
orm
al S
truc
tura
l Mod
els
A F
orm
al O
O-R
ML/
Tel
osD
efic
ien
cies
of
SA
RM
L/T
elos
Ess
entia
lsA
For
ma
liza
tion
A B
rief
Sur
vey
of F
Ms
Met
am
odel
ing Mod
els,
Met
acl
ass
e, M
eta
mod
els
Met
am
odel
s fo
r U
ML
an
d ot
her
not
atio
ns
Fun
ctio
na
l Req
uire
men
ts: B
eha
vior
al M
odel
s[D
avi
s.C
h4]
Dec
isio
n-o
rien
ted
Sta
te-o
rien
ted
Fun
ctio
n-o
rien
ted
beh
avi
ora
l mod
els
Non
-Fun
ctio
na
l Req
uire
men
ts[C
NY
M, 2
000;
LK
.Ch5
; Dav
is.C
h6]
Wh
yN
FR
sW
ha
t –de
finiti
ons
an
d cl
ass
ifica
tion
sH
ow –
prod
uct-
an
d pr
oces
s-or
ien
ted
app
roa
ches
Ano
ther
pos
sibl
e to
pic:
Mod
el C
heck
ing
Par
ts o
f Lec
ture
Not
es C
ome
Fro
m
Plu
s ot
her
refe
renc
es a
s in
the
sylla
bus
Plu
s so
me
sele
cted
art
icle
s (o
n th
e ne
xt s
lide)
Plu
s ar
ticle
s an
d w
eb r
esou
rces
as
indi
cate
d in
indi
vidu
al m
odul
es
Par
ts o
f Lec
ture
Not
es C
ome
Fro
mS
ome
sele
cted
art
icle
s•
A. I
. Ant
on a
nd C
. Pot
ts, “
Fun
ctio
nal p
aleo
ntol
ogy:
sys
tem
evo
lutio
n as
the
user
see
s it,
” P
roc.
, 23rd
IEE
E In
t. C
onfe
renc
e on
S
oftw
are
Eng
inee
ring
(IC
SE
'01)
,Tor
onto
, Can
ada,
12-
19 M
ay, 2
001.
pp.
421
-430
. •
B. B
oehm
H. I
n, “
Iden
tifyi
ng q
ualit
y-re
quire
men
t con
flict
s,” I
EE
E S
oftw
are
13 (
2) 2
5-35
. Mar
ch 1
996.
•
M. S
. Fea
ther
and
S. L
. Cor
nfor
d, “Q
uant
itativ
e ris
k-ba
sed
requ
irem
ents
reas
onin
g,” R
equi
rem
ents
Eng
inee
ring,
Vol
8, p
p. 2
48–2
65.
•R
. G. F
ichm
an a
nd C
. F. K
emer
er, “
Obj
ect-
orie
nted
and
con
vent
iona
l ana
lysi
s an
d de
sign
met
hodo
logi
es,”
IE
EE
Com
pute
r, 2
5 (1
0) 2
2 -3
9, O
ct. 1
992.
•X
. Fra
nch,
“Sys
tem
atic
form
ulat
ion
of n
on-f
unct
iona
l cha
ract
eris
tics
of s
oftw
are,
” Pro
c., 3
rdIn
t. C
onfe
renc
e on
Req
uire
men
ts
Eng
inee
ring,
(IC
RE
'98)
.6-1
0 A
pril
1998
. pp.
174-
181.
IEE
E C
ompu
ter S
ocie
ty P
ress
. •
M. G
linz,
“P
robl
ems
and
Def
icie
ncie
s of
UM
L as
a R
equi
rem
ents
Spe
cific
atio
n La
ngua
ge,”
Pro
c. o
f the
10th
Int.
Wor
ksho
p on
S
oftw
are
Spe
cific
atio
n an
d D
esig
n (I
WS
SD
-10)
,200
0.•
J. G
ogue
n an
d C
. Lin
de, “
Tec
hniq
ues
for R
equi
rem
ents
Elic
itatio
n,” P
roc.
, 1st
IEE
E In
t. S
ympo
sium
on
Req
uire
men
ts E
ngin
eerin
g (R
E'9
3)S
an D
iego
, Cal
iforn
ia, U
SA
, pp.
152
-164
. IE
EE
Com
pute
r Soc
iety
Pre
ss.
•O
. C. Z
. Got
el a
nd A
. C. W
. Fin
kels
tein
, “C
ontr
ibut
ion
Str
uctu
res,
” Pro
c. o
f the
2nd
IEE
E In
t. S
ympo
sium
on
Req
uire
men
ts
Eng
inee
ring
(RE
'95)
,Yor
k, U
K, p
p. 1
00-1
07, M
arch
27-
29 1
995.
IEE
E C
ompu
ter S
ocie
ty P
ress
. •
S. G
reen
span
, J. M
ylop
oulo
s an
d A
. Bor
gida
, “O
n fo
rmal
requ
irem
ents
mod
elin
g la
ngua
ges:
RM
L re
visi
ted,
” P
roc.
, 16th
Int.
Con
fere
nce
on S
oftw
are
Eng
inee
ring
(IC
SE
-16)
pp13
5 -1
47. I
EE
E C
ompu
ter S
ocie
ty P
ress
. •
M. P
. E. H
eim
dahl
and
N. G
. Lev
eson
, “C
ompl
eten
ess
and
Con
sist
ency
in H
iera
rchi
cal S
tate
-Bas
ed R
equi
rem
ents
,”
IEE
E T
rans
actio
ns o
n S
oftw
are
Eng
inee
ring,
Vol
22
No
6, J
une
1996
. •
C. L
. Hei
tmey
er, R
. D. J
effo
rds
and
B. G
. Lab
aw, “
Aut
omat
ed C
onsi
sten
cy C
heck
ing
of R
equi
rem
ents
Spe
cific
atio
ns,”
A
CM
Tra
nsac
tions
on
Sof
twar
e E
ngin
eerin
g an
d M
etho
dolo
gy,5
(3),
231
-261
. •
A. M
. Hic
key
and
A. M
. Dav
is,
“Elic
itatio
n te
chni
que
sele
ctio
n: h
ow d
o ex
pert
s do
it?,
” P
roc.
, 11t
h IE
EE
Int.
Req
uire
men
ts
Eng
inee
ring
Con
fere
nce
(RE
'03)
,Mon
tere
y B
ay, U
SA
, 8-1
2th
Sep
t. 20
03, p
p. 1
69-1
78. I
EE
E C
ompu
ter S
ocie
ty P
ress
.
Par
ts o
f Lec
ture
Not
es C
ome
Fro
mS
ome
sele
cted
art
icle
s•
M. J
acks
on, “
The
Mea
ning
of R
equi
rem
ents
,” A
nnal
s of
Sof
twar
e E
ngin
eerin
g, V
ol 3
, pp5
-21,
Bal
tzer
Sci
ence
Pub
lishe
rs. 1
997.
•A
. van
Lam
swee
rde,
"Req
uire
men
ts e
ngin
eerin
g in
the
year
00:
a r
esea
rch
pers
pect
ive"
, Pro
c., t
he 2
2nd
Int.C
onfe
renc
e on
Sof
twar
e E
ngin
eerin
g (I
CS
E'0
0),L
imer
ick,
Irel
and,
5-9
th J
une,
200
0, p
p5-1
9. IE
EE
Com
pute
r Soc
iety
Pre
ss.
•A
. van
Lam
swee
rde,
“Goa
l-Orie
nted
Req
uire
men
ts E
ngin
eerin
g: A
Gui
ded
Tou
r. P
roc.
, 5th
IEE
E In
t. S
ympo
sium
on
Req
uire
men
ts
Eng
inee
ring
(RE
'01)
,Tor
onto
, Aug
., 20
01, p
p. 2
49-2
63. I
EE
E C
ompu
ter S
ocie
ty P
ress
. •
N. M
aide
n an
d S
. Rob
erts
on, “
Inte
grat
ing
Cre
ativ
ity in
to R
equi
rem
ents
Pro
cess
es: E
xper
ienc
es w
ith a
n A
ir T
raff
ic M
anag
emen
t S
yste
m,”
Pro
c., 1
3th
IEE
E In
tern
atio
nal R
equi
rem
ents
Eng
inee
ring
Con
fere
nce
(RE
'05)
,Par
is, F
ranc
e, A
ug 2
9 -
Sep
t 2, 2
005.
•
J. M
ylop
oulo
s, L
. Chu
ng a
nd B
. Nix
on, “
Rep
rese
ntin
g an
d us
ing
nonf
unct
iona
l req
uire
men
ts: a
pro
cess
-orie
nted
app
roac
h,”
IEE
E T
rans
actio
ns o
n S
oftw
are
Eng
inee
ring,
Vol
18,
Issu
e 6,
Jun
e 19
92, p
p. 4
83 -
497.
•
B. A
. Nus
eibe
h an
d S
. M. E
aste
rbro
ok, "
Req
uire
men
ts E
ngin
eerin
g: A
Roa
dmap
", In
A. C
. W. F
inke
lste
in (
ed.)
The
F
utur
e of
Sof
twar
e E
ngin
eerin
g. (C
ompa
nion
vol
ume
to th
e pr
oc. o
f IC
SE
'00)
. IE
EE
Com
pute
r Soc
iety
Pre
ss.
•D
. L. P
arna
s, “F
orm
al M
etho
ds”
Tec
hnol
ogy
Tra
nsfe
r Will
Fai
l,’
Jour
nal o
f Sys
tem
s an
d S
oftw
are.
Vol
. 40,
Issu
e: 3
. Mar
ch, 1
998.
pp.
195
-198
•
C. P
otts
and
W. C
. New
stet
ter,
“Nat
ural
istic
inqu
iry a
nd re
quire
men
ts e
ngin
eerin
g: re
conc
iling
thei
r th
eore
tical
foun
datio
ns,”
P
roc.
, 3rd
IEE
E In
t. S
ympo
sium
on
Req
uire
men
ts E
ngin
eerin
g (R
E'9
7),A
nnap
olis
, US
A, p
p. 1
18 -1
27. I
EE
E C
ompu
ter S
ocie
ty P
ress
. •
B. R
ames
h an
d M
. Jar
ke, “
Tow
ard
refe
renc
e m
odel
s fo
r req
uire
men
ts tr
acea
bilit
y,” I
EE
E T
rans
actio
ns o
n S
oftw
are
Eng
inee
ring,
Vol
ume:
27
1, J
anua
ry 2
001,
pp.
58
-93.
•
A. S
utcl
iffe,
“Sce
nario
-bas
ed re
quire
men
ts e
ngin
eerin
g,” P
roc.
, 11t
h IE
EE
Int.
Req
uire
men
ts E
ngin
eerin
g C
onfe
renc
e (R
E'0
3),
Mon
tere
y B
ay, U
SA
, 8-1
2th
Sep
t. 20
03, P
ages
: 320
-329
. IE
EE
Com
pute
r Soc
iety
Pre
ss.
•J.
Whi
ttle
and
J. S
chum
ann,
“Gen
erat
ing
stat
echa
rt d
esig
ns fr
om s
cena
rios,
” Pro
c., 2
2nd
IEE
E In
t. C
onfe
renc
e on
Sof
twar
e E
ngin
eerin
g (I
CS
E-0
0),L
imer
ick,
Irel
and,
4-1
1 Ju
ne 2
000.
Pag
es: 3
14-3
23.
•W
. M. W
ilson
, L. H
. Ros
enbe
rg a
nd L
. E. H
yatt,
“Aut
omat
ed A
naly
sis
of R
equi
rem
ent S
peci
ficat
ions
,” P
roc.
of t
he 1
9thIn
t. C
onfe
renc
e on
Sof
twar
e E
ngin
eerin
g (I
CS
E-9
7),B
osto
n, M
A, M
ay 1
7-23
, pp.
161
-171
. •
E. S
. K. Y
u, “
Tow
ards
mod
ellin
g an
d re
ason
ing
supp
ort f
or e
arly
-pha
se re
quire
men
ts e
ngin
eerin
g,” P
roc.
, 3rd
IEE
E In
t. S
ympo
sium
on
Req
uire
men
ts E
ngin
eerin
g (R
E'9
7),A
nnap
olis
, US
A, p
p 22
6 -2
35. I
EE
E C
ompu
ter S
ocie
ty P
ress
.•
P. Z
ave
and
M. J
acks
on, “
Fou
r D
ark
Cor
ners
of R
equi
rem
ents
Eng
inee
ring,
” A
CM
Tra
nsac
tions
on
Sof
twar
e E
ngin
eerin
g an
d M
etho
dolo
gy6(
1) 1
-30.
AC
M P
ress
. 199
7.
evol
utio
n
softgoal satisficing
softgoal satisficing
softgoal satisficing
softgoal satisficing
R:
a m
odel
of
the
requ
irem
ents
D:
a m
odel
of
the
envi
ronm
ent
S:
a m
odel
of
the
sw b
ehav
ior
satis
fy
acts upon
constrains
G: g
oals
FnNFn
W WWW R RRR S SSS
M MMMG GGG, Prog
Prog
Prog
ProgG GGG|= S SSS
G GGG; S SSSG GGG, D DDDG GGG|= R RRR
G GGG; R RRRG GGG, D DDDG GGG|= G GGG; (G GGG|= ¬ ¬¬¬P PPP) V (G GGG|~ ¬ ¬¬¬P PPP)
