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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