Hazırlayan
SSADM – Structured Systems Analysis andDesign Method
Yard.Doç.Dr.ZehraKAMIŞLIÖZTÜRK
(Structured System Analysis & Design Methodology - SSADM)
basic principles1. topdown functional decomposition
analyze levelBreakdown functional complex system into chunksü Ignorethesmalldetailsuntilitengagesthekeyfeaturesofthe
system
Lowerlevelsofthesystemareconsideredindetail,later on
SSADM
2. Requirement of explanation
SSADM
physicalperspectives
ofthecurrentsystem
• howthingsarecurrentlydoneand whodoesthem?
Logical pointofview
•whatiscurrentlydoneor?
• Thiscompletestheanalysisphase,andthenit’sontodesign
•Whatthenewsystemshoulddo?Whoandhowwilldo?
physicalaspectsofthecurrentsystem
2. Requirement of explanation
SSADM
3. SSADM requires users to get involved from the start
SSADM
Theanalystmustmeettheusersregularlytosortoutproblems andcheckunderstanding.
SSADM,wouldinvolveusersfromthebeginningStay happy inthe new system
4. effective use of diagrams
i. Formingdetailed logicaldatastructureii. Establishingmultipart datastructuremultipartiii. Creatingdatadictionary
Ø likeamapofthesystem
SSADM
5. SSADM allows the analyst to see the system from different views
checktoseeifthedifferentviewsmatchupCross-checking
SSADM
6. SSADM is an industry standard
• 1980’lerinbaşındakullanılmayabaşlanmıştır.• SSADMSSADM,genellikledevletbilgisayarprojeleriiçinbirgereklilikolarakbelirtilenİngiltere'deyaygınolarakkullanılanbirbilgisayaruygulamageliştirme
yöntemidir.GiderekAvrupa'dakamusektörütarafındankabuledilmiştir.• SSADMkamumalıdırveİngilizStandardıBS7738ilebelirtilir.
• It hasbeen used science early 1980’s.• SSADM,isawidely-usedcomputerapplication
developmentmethodintheUK,whereitsuseisoftenspecifiedasarequirementforgovernmentcomputingprojects.
• ItisincreasinglybeingadoptedbythepublicsectorinEurope.
• SSADMisinthepublicdomain,andisformallyspecifiedinBritishStandardBS7738.
SSADM's objectives are to:
• Improveprojectmanagement&control• Makemoreeffectiveuseofexperiencedandinexperienced
developmentstaff• Developbetterqualitysystems• Makeprojectsresilienttothelossofstaff• Enableprojectstobesupportedbycomputer-basedtools
suchascomputer-aidedsoftwareengineeringsystems• Establishaframeworkforgoodcommunicationsbetween
participantsinaproject
The structure of SSADM
Stage 0. Feasibility
Technical– istheprojecttechnicallypossible?
Financial– canthebusinessaffordtocarryouttheproject?
Organizational– willthenewsystembecompatiblewithexisting
practices?
Ethical– istheimpactofthenewsystemsociallyacceptable?
SSADM
Stage 1 – Investigation of the current environment
• Throughacombinationofinterviewingemployees,circulatingquestionnaires,observationsandexistingdocumentation,theanalystcomestofullunderstandingofthesystemasitisatthestartoftheproject.
Stage 2 – Business system options
• thedegreeofautomation• theboundarybetweenthesystemandtheusers• thedistributionofthesystem,forexample,isitcentralizedtooneofficeorspreadoutacrossseveral?
• cost/benefit• impactofthenewsystem
Stage 3 – Requirements specification
• Toproducethelogicalspecification,theanalystbuildstherequiredlogicalmodelsforboththe data-flowdiagrams (DFDs)andtheLogicalDataModel(LDM),consistingoftheLogicalDataStructure(referredtoinothermethodsas entityrelationshipdiagrams)andfulldescriptionsofthedataanditsrelationships.
Stage 4 – Technical system options
• thehardwarearchitectures• thesoftwaretouse• thecostoftheimplementation• thestaffingrequired• thephysicallimitationssuchasaspaceoccupiedbythe
system• thedistributionincludinganynetworkswhichthatmay
require• theoverallformatofthehumancomputerinterface
Stage 5 – Logical design
• theoutputsofthisstageareimplementation-independentandconcentrateontherequirementsforthehumancomputerinterface.
Stage 6 – Physical design
• Thisisthefinalstagewhereallthelogicalspecificationsofthesystemareconvertedtodescriptionsofthesystemintermsofrealhardwareandsoftware.
Swillbuckets Country Club
The CaseStudies
Swillbuckets Country Club
• Tasks:– Reservation ofartists– Newmemberships– Preparing receipts to artists– Promotionoffutureevents– chasing memberships– Nicemeatdishes!rewardthe Chief!!
Swillbuckets Country Club
• Card-baseddatastorage system– Usersandartists– 2-3shoeboxes– NotanAdequatestorage system!!– There isn’t anoption to openanewboxand/orinformation system
– Subscriptionfeesofthemembers- assistant:Amanda
Definition of the problem
• Amandaisnotpatient!!•She wants fromJack the list ofmemberswho havedelayedpaymentsIwantthelist(2weeksago)
•Isitpossible for Jack toremovethelistfromthebox??
Definition of problem -2
• changingcustomerrecords• Creation ofMonthly"futureevents"list• announce these events to thelocalpress
Definition of problem- Food Service
• They have awell-plannedfoodrange• Meat,especiallyorganmeats,expert• Severalsuppliers– Reliable?
• Paymentsaremadeincash• Unknown instant stockrecordsunknown– Itremainsadifficultsituationwhilecookingfor chef
• Last-minutechangesinmenus
Problem background
• Appointments:chaotic,withdoublebookings,noroomforurgent cases,andchangesnotmade.Afoolproofsystemofappointmentsisthe toppriorityfortheCentre.
• Patientprocessing:thefilingofrecordsishaphazard.Theycango missing,orbemisfiled.Withsuchahighturnoverofpatients,the recordsarenotalwaysmaintainedaccurately.Muchinformationis duplicatedandoftendisparitiesappear.Thedoctorsrequireawayof viewingpatientrecordswithouthavingtokeepgoingbackwardsand forwardstoseeBettyandGeorge.Prescriptionsarenormallyillegible, whichresultsinHeatherinthechemistshavingtopopinregularlyto have them decrypted.
Problem backgroundmanagement information: the GPC requires regular informationabout the hours doctors have worked, new patients, supplies used etc.Currently, Nurse Payne attempts to produce these, but mathematics is nother strong point.The staff time sheets are a mess and staff often get paid for hours theyhaven’t worked. The accountant is not happy aboutthis. Neither is the GPC.The GPC also needs regular updates on currently enrolled patients. It is theresponsibility of the receptionists to record when patients leave and keep alist of patients for each doctor. However, the University does not tell themwhen a student withdraws, and patients rarely think to inform them whenthey move away.
Problem background
The only information it gets is from the GPC when it issues a new MedicalCard for another practice, or from the Registrar of Deaths. Betty gets quitequeasy when she has to tear up someone’s medical records and throw themin the bin.The Prescription Monitoring Agency also requires information about whatprescriptions have been issued so that it can compare different practices andsee who is out of line. It sends a report every six months to the Centre. This isshredded and used as a home for the hamster.Theaccountantrequiresregularfinancialinformationaboutoutgoings.ThisisthebaneofNursePayne’slife.Aproperaccountingsystemis required.
Orderingsupplies:onamoremundanenote,NursePaynehasnoinformation aboutpotentialsuppliers,otherthanthecataloguesshekeeps underherdesk.Shemaybepayingtoomuchforbandagesetc.Sheis keentofindoutmoreaboutsomerecycledCrimeanWarbandagesthat herfriend,Nurse Bluntmentioned to her.
Registration:ithasbeenknownforthereceptioniststotakedown detailswrongly(e.g.‘bloodgroup’),ortoomitkeywordssuchas ‘haemophiliac’.Thesetypingerrorshavehadunnervingresults.Also, GeorgeandBettyhavehadproblemstryingtodeterminewhoiseligible tojointhepractice.Astreetmapwithfelttiplinesonithasproventobea lessthanadequatetool.Ideally,theywanttobeabletosayinstantantly if apostcodeiswithintheircatchmentarea.
Staff
• 4doctors- everydoctor hashis/herownpatient list
• Patientscango anotherphysician• 1nurse:prescriptionwriting&orderinginjection&syringe- plasticandsoon.
• 2receptionist&1traineereceptionist:– patient tailsandappointments
Summary of the problems
• Appointments– Complex,dualenrollment,no emergencyrooms
• Patientprocess– Randomrecords, notupdatedrecords– Doctorsdonotknowthepatientcasehistory
• Prescriptionsare illegible:influenceofpharmacist
Summary of the problems
•Managementinformation• RegularinformationrequestedbytheGPC
•workinghoursofdoctors•Newpatient•Suppliers...•Chartsinadequate.accounting&GPC:(
• GPCnewrecords• Anappropriateaccountingsystem
•suppliersDoNursesknowpotentialsuppliers??•Theremaybemoremoneytobandage!!
•Register– Receptionistmissingrecords(majordiseases)ortakethewrongrecord
•Haşimato /0rhpositive