??ad??as?a a??pt????

1
??ad??as?a a??pt????
???sd????sµ?? apa?t?se??
???? t? p??ß??µa ?
????te?t?????? S?ed?asµ??
???a ? ??s? ?
??? ?a ???p????e? ? ??s? ?
?ept?µe??? S?ed?asµ??
??d???p???s?
??d??a? ???
??e????
?p??????e t? p??ß??µa?
????p??e? ? pe??t?? t? ??s? ?
?a??d?s? S?st?µat??
?a???s?????ta? p??ß??µata ?
?e?t?????a - S??t???s?
2
???sd????sµ?? ?pa?t?se??

• S?st?µat??? p??s????s? ??a t?? ?a????sµ? se ??a
  s?st?µa
• t?? ?e?t??????? p?? p??pe? ?a e?te?e?
• t?? pe?????sµ?? st??? ?p????? ?p??e?ta?
• !!! ?a???????µe t? p??pe? ?a ???e? t? s?st?µa
• ??? t?? t??p? µe t?? ?p??? ?a t? ???e?

3
???sd????sµ?? ?pa?t?se??

• ???????G??
• (????sµ??? ??t?????t??)
• ?e?t???????? ?pa?t?se??
• (?????ep?d?as? s?st?µat?? pe??ß?????t??)
• ?p?????sµ?? µ?s?? ?ata????s?? ?a?s?µ??
• ?p?????sµ?? µ?s? ???a?a? ta??t?ta?
• ?p?????sµ?? ß??t?st?? ta??t?ta?
• ?e?????sµ??
• ???p???s? se ???ssa C
• ?p????s? se 5 secs
• ???µ? lt 100 Kb

4
???a? ?? apa?t?se?? s?µa?t???? ?

• 1994 ?e??t? 350 eta????? 8000 ???a ????sµ????
• 31 t?? ????? a???????a? p??? ap? t?? ????????s?
• 9 t?? ????? pa?ad????a? e??a???? ?a? e?t??
  p???p?????sµ?? ap? µe???e? eta??e?e?
• 16 t?? ????? pa?ad????a? e??a???? ?a? e?t??
  p???p?????sµ?? ap? µ????? eta??e?e?
• ??t?e?
• ????pe?? apa?t?se?? (13.1 )
• ?? s?µµet??? t?? ???st?? (12.4 )
• ???e??? p???? (10.6 )
• ???p?a?µat???? apa?t?se?? (9.9 )
• ???a??? st?? apa?t?se?? (8.7 )
• ??epa???? p????aµµat?sµ?? (8.1 )
• ?? s?st?µa de? ??e?a??ta? p???? (7.5 )

Pfleeger
5
??at?p?s? ???ß??µat??
?ta??e?a ?e??t?? (p.?. ???)
6
?????s? ?pa?t?se??
?????? ?e????af?
??a??t?? S?st?µ?t??
????af? ?e????af?? ?pa?t?se?? ap? t?
S?st?µa (???S)
7
?????s? ?pa?t?se?? ??

• ?? ?a ???e? t? s?st?µa
• ?ata??µ? ?e?t??????? se H/W, S/W, Users
• ?e?????sµ?? st?? a??pt??? ?a? ?e?t?????a
• G?a ?a ?a????s??µe ta a??t???
• ??t?p?sµ?? ?????? ?e?t??????? apa?t?se??
  ep?d?s??
• ???tas? ?p?????t?? ?????? ????sµ????
• ????? ?a? ??? p????f???a?
• ??ad??as?e? a????ep?d?as?? s?st?µat?? - ???st??

8
??p?? apa?t?se??
F?s??? pe??ß?????
??epaf??
???ste?
?pa?t?se??
?e?t?????-??t?ta
????t?ta
?sf??e?a
?e?µ????s?
?????
?ed?µ??a
9
?p?????s? apa?t?se??

• ???a? ?? apa?t?se??
• S?st?? ? (??af????ta? se a?t? p?? ?????µe ?)
• S??epe?? (???pa???a a?t?f?se??)
• ????e?? (?e?????f??ta? ??e? ?? d??at??
  ?atast?se?? ?)
• ??a?µat?p???s?µe? ?
• ??s?ast???? ? (??? ??e???eta? ? pe??t?? ?)
• ?pa???e?s?µe? ? (?p?????? ??e???? p?? ?a
  de?????? ?t? ?a???aµe t?? apa?t?se?? ?)
• ?????at?s?µe? ? (p??? tµ?µa t?? s?st?µat??
  s?et??eta??)

10
?p?????s? apa?t?se??

• ?pa?t?s?
• ?? s?st?µa p??pe? ?a e?asfa???e? ap????s? e?t??
  p?a?µat???? ?????? ??a t?? ????e? ?e?t?????e?.
• Se p??e? ????e? ?e?t?????e? a?af??eta? ?
• ?? s?µa??e? p?a?µat???? ?????? ?
• ?? µ?a ????a ?e?t?????a e??a? se µ???a?a ß?s?,
  ??at? p??pe? ?a e?te?e?ta? se p?a?µat??? ????? ?

11
Level of abstraction
?ta??e?a ?e??t?? (p.?. ???)
12
Documentation

• ????af? ???sµ?? ?pa?t?se?? (Requirements
  Definition)
• (f?s??? ???ssa d?a???µµata)
• ?p??e? ?a t? ????e? ?a? ? pe??t??
• ????af? ???sd????sµ?? ?pa?t?se?? (Requirements
  Specification)
• ????ß?? ?a? d?µ?µ??? ?e?µe??
• a?apt?sseta? ap? t?? ?atas?e?ast?
• s???de?e? s???? t? s?µß??a??
• µp??e? ?a s???de?eta? ap? pe????af? ????sµ????

13
???sµ?? ?pa?t?se?? (?a??de??µa)
?? ????sµ??? p??pe? ?a pa???e? t? d??at?t?ta
p??ß???? ?a? p??sßas?? e??te????? a??e??? p??
d?µ????????ta? ap? ???a e??a?e?a
-?-

?e??t??
14
???sd????sµ?? ?pa?t?se?? ?a??d.
1.1 ? ???st?? ?a p??pe? ?a µp??e? ?a ????e? t???
t?p??? t?? e??te????? a??e??? 1.2 ???e e??te????
a??e?? µp??e? ?a s??d?eta? µe ??p??a efa?µ??? p??
?a t? ???s?µ?p??e? 1.3 ???e e??te???? a??e?? ?a
e??a? ??at? sa? e?????d?? st?? ????? t??
???st? 1.4 ? ???st?? ?a p??pe? ?a ??e? t?
d??at?t?ta ?a ?a????se? t?? t?p? t?? e?????d???
??a ???e a??e?? 1.5 ?ta? ? ???st?? ep????e? ??a
e?????d?? ?a p??pe? ?a e?e???p??e?ta? ?
s??dedeµ??? µe a?t? t? a??e?? efa?µ???
15
Readers
16
???ß??µata

• ??a?t???, e??a? ad??at? ?a ?a????s??µe p????? ?a?
  µe a???ße?a t?? apa?t?se?? e??? s?st?µat??
• ?e???? ????p????t?ta
• ?pa?t?se?? eµfa?????ta? ?at? t?? a??pt??? t??
  ????sµ????
• ?????? d?af??et???? ???ste? µe d?af??et???
  ?pt??? ????a ? ?a???a?

17
????d?? ???sd????sµ?? ?pa?t?se??

• ?t?pe?
• ?µ?t?p????
• ??p????

• ?e?t???????? p??d?a??af?? (operational
  specifications) ?e????af? t?? s?st?µat??
  a?af????ta? t?? ep???µ?t? s?µpe??f???
• ?e????af???? p??d?a??af?? (descriptive
  specifications) ?e????af? t?? s?st?µat??
  a?af????ta? t?? ep???µ?t?? ?d??t?te?

18
????d?? ???sd????sµ?? ?pa?t?se??

• ?p????te d?? s?µe?a P1, P2 se ??a ep?ped?
• ?p????te ??a ??µa s???e???µ???? µ????? ?a?
  p??sa?t?ste ta ???a t?? sta P1 ?a? P2
• ??p??et?ste µ?a ??af?da ep??? st? ??µa
• ?eta????ste t? ??af?da pe??st??f??? se epaf? µe
  t? ??µa, ??at??ta? t? ??µa te?t?µ??? µ????? ?t??
  f??sete st? a????? s?µe??
• ?e?t??????? ???d?a??af? µ?a? ???e????

19
????d?? ???sd????sµ?? ?pa?t?se??
20
????d?? ???sd????sµ?? ?pa?t?se??
?e????af??? ???d?a??af? µ?a? ???e???? a x2 b
y2 c 0
21
????d?? ???sd????sµ?? ?pa?t?se??

• ?st? a ??a? p??a?a? n st???e???. ?? ap?t??esµa
  t?? ta????µ?s?? t?? a e??a? ??a? p??a?a? b µe n
  st???e?a ? ?p???? µp??e? ?a ?atas?e?aste? ??
  e???
• ???es? t?? µ????te??? st???e??? t?? a ?a?
  t?p???t?s? t?? st?? p??t? ?e?? ??s? t?? b
• ?p?µ?????s? t?? st???e??? p?? ß?????e st?
  p??????µe?? ß?µa ap? t?? a.
• ?pa?????? t?? 1 ?a? 2 µ????? ?t?? e?a?t?????? ta
  st???e?a t?? a

Ghezzi
22
????d?? ???sd????sµ?? ?pa?t?se??
"?? ap?t??esµa t?? ta????µ?s?? e??? p??a?a a
e??a? ??a? p??a?a? b ? ?p???? ap?te?e? µet??es?
(permutation) t?? a ?a? e??a? ta????µ?µ????"
Ghezzi
23
?e?????af???? ????d?? - HIPO
???G??????? HIPO (HIERARCHY INPUT PROCESS
OUTPUT) 1. ?????aµµa ? s?st?µat?? (?e?a???a
?e?t???????)
S?st?µa ?pe?e??as?a? ?e?µ???? 1
???p?p???s? ?e?µ???? 1.1
??µ??????a ?e?µ???? 1.2
??t?p?s? ?e?µ???? 1.3
???e????t?s? ?e?µ???? 1.4
???d?? 1.5
??a??af? ?e?µ???? 1.4.1
??t???af? ?e?µ???? 1.4.2
?at?????? ?e?µ???? 1.4.3
G?a???µ????
24
HIPO - II
???G??????? HIPO (HIERARCHY INPUT PROCESS
OUTPUT) 1. ??a???µµata ??s?d?? ?pe?e??as?a? -
???d??
1.3 ??t?p?s? ?e?µ????
INPUT
PROCESS
OUTPUT
?p? te?µat??? File name Password Printer
No. Print options ?p? ß?ß??????? ???e??
?e?µ????
If passwd correct file exists send
file to prnt Else print message
??t?p?s? a??e??? ????µata ??????
25
HIPO - III

• ???G??????? HIPO
• MEIONEKTHMATA
• ?e?????f??? µ??? t?? ?e?t???????? apa?t?se??
  (?e? d?a??t??? µ??a??sµ? ?e???sµ?? pe?????sµ??)
• ?e? ?p?????? µ??a??sµ?? e?????? (?pa???e?s? µ???
  µe p??se?t??? µe??t?)