系統(tǒng)分析與設(shè)計(jì)ppt3

SystemsAnalysisandDesigninaChangingWorld,FourthEditionSystemsAnalysisandDesigninaChangingWorld,4thEdition2LearningObjectivesDiscussexamplesofsysteminterfacesfoundininformationsystemsDefinesysteminputsandoutputsbasedontherequirementsoftheapplicationprogramDesignprintedandon-screenreportsappropriateforrecipientsSystemsAnalysisandDesigninaChangingWorld,4thEdition3LearningObjectives(continued)ExplaintheimportanceofintegritycontrolsIdentifyrequiredintegritycontrolsforinputs,outputs,data,andprocessingDiscussissuesrelatedtosecuritythataffectthedesignandoperationofinformationsystemsSystemsAnalysisandDesigninaChangingWorld,4thEdition4OverviewThischapterfocusesonsysteminterfaces,systemoutputs,andsystemcontrolsthatdonotrequiremuchhumaninteractionManysysteminterfacesareelectronictransmissionsorpaperoutputstoexternalagentsSystemdevelopersneedtodesignandimplementintegrityandsecuritycontrolstoprotectsystemanditsdataOutsidethreatsfromInternetande-commercearegrowingconcernSystemsAnalysisandDesigninaChangingWorld,4thEdition5IdentifyingSystemInterfacesSysteminterfacesarebroadlydefinedasinputsoroutputswithminimalornohumaninterventionInputsfromothersystems(messages,EDI)HighlyautomatedinputdevicessuchasscannersInputsthatarefromdatainexternaldatabasesOutputstoexternaldatabasesOutputswithminimalHCIOutputstoothersystemsReal-timeconnections(bothinputandoutput)SystemsAnalysisandDesigninaChangingWorld,4thEdition6FullRangeofInputsandOutputsSystemsAnalysisandDesigninaChangingWorld,4thEdition7eXtensibleMarkupLanguage(XML)ExtensionofHTMLthatembedsself-defineddatastructuresintextualmessagesTransactionthatcontainsdatafieldscanbesentwithXMLcodestodefinemeaningofdatafieldsXMLprovidescommonsystem-to-systeminterfaceXMLissimpleandreadablebypeopleWebservicesisbasedonXMLtosendbusinesstransactionsoverInternetSystemsAnalysisandDesigninaChangingWorld,4thEdition8System-to-SystemInterfaceBasedonXMLSystemsAnalysisandDesigninaChangingWorld,4thEdition9DesignofSystemInputsIdentifydevicesandmechanismsusedtoenterinputHigh-levelreviewofmostup-to-datemethodstoenterdataIdentifyallsysteminputsanddeveloplistofdatacontentforeachProvidelinkbetweendesignofapplicationsoftwareanddesignofuserandsysteminterfacesDeterminecontrolsandsecuritynecessaryforeachsysteminputSystemsAnalysisandDesigninaChangingWorld,4thEdition10InputDevicesandMechanismsCapturedataasclosetooriginalsourceaspossibleUseelectronicdevicesandautomaticentrywheneverpossibleAvoidhumaninvolvementasmuchaspossibleSeekinformationinelectronicformtoavoiddatare-entryValidateandcorrectinformationatentrypointSystemsAnalysisandDesigninaChangingWorld,4thEdition11PrevalentInputDevices

toAvoidHumanDataEntryMagneticcardstripreadersBarcodereadersOpticalcharacterrecognitionreadersandscannersRadio-frequencyidentificationtagsTouchscreensanddevicesElectronicpensandwritingsurfacesDigitizers,suchasdigitalcamerasanddigitalaudiodevicesSystemsAnalysisandDesigninaChangingWorld,4thEdition12DefiningtheDetailsofSystemInputsEnsurealldatainputsareidentifiedandspecifiedcorrectlyCanusetraditionalstructuredmodelsIdentifyautomationboundaryUseDFDfragmentsSegmentbyprogramboundariesExaminestructurechartsAnalyzeeachmoduleanddatacoupleListindividualdatafieldsSystemsAnalysisandDesigninaChangingWorld,4thEdition13AutomationBoundaryona

System-LevelDFDSystemsAnalysisandDesigninaChangingWorld,4thEdition14CreateNewOrderDFDwith

anAutomationBoundarySystemsAnalysisandDesigninaChangingWorld,4thEdition15ListofInputsforCustomerSupportSystemSystemsAnalysisandDesigninaChangingWorld,4thEdition16StructureChartforCreateNewOrder

(Figure14-6)SystemsAnalysisandDesigninaChangingWorld,4thEdition17DataFlows,DataCouples,andDataElementsMakingUpInputs(Figure14-7)SystemsAnalysisandDesigninaChangingWorld,4thEdition18UsingObject-OrientedModelsIdentifyinguserandsysteminputswithOOapproachhassametasksastraditionalapproachOOdiagramsareusedinsteadofDFDsandstructurechartsSystemsequencediagramsidentifyeachincomingmessageDesignclassdiagramsandsequencediagramsidentifyanddescribeinputparametersandverifycharacteristicsofinputsSystemsAnalysisandDesigninaChangingWorld,4thEdition19PartialSystemSequenceDiagramfor

PayrollSystemUseCases(Figure14-8)SystemsAnalysisandDesigninaChangingWorld,4thEdition20SystemSequenceDiagramfor

CreateNewOrderSystemsAnalysisandDesigninaChangingWorld,4thEdition21InputMessagesandDataParameters

fromRMOSystemSequenceDiagram(Figure14-10)SystemsAnalysisandDesigninaChangingWorld,4thEdition22DesigningSystemOutputsDetermineeachtypeofoutputMakelistofspecificsystemoutputsrequiredbasedonapplicationdesignSpecifyanynecessarycontrolstoprotectinformationprovidedinoutputDesignandprototypeoutputlayoutAdhocreports–designedasneededbyuserSystemsAnalysisandDesigninaChangingWorld,4thEdition23DefiningtheDetailsofSystemOutputsTypeofreportsPrintedreportsElectronicdisplaysTurnarounddocumentsCanusetraditionalstructuredmodelstoidentifyoutputsDataflowscrossingautomationboundaryDatacouplesandreportdatarequirementsonstructurechartSystemsAnalysisandDesigninaChangingWorld,4thEdition24TableofSystemOutputsBasedonTraditionalStructuredApproach(Figure14-11)SystemsAnalysisandDesigninaChangingWorld,4thEdition25UsingObject-OrientedModelsOutputsindicatedbymessagesinsequencediagramsOriginatefrominternalsystemobjectsSenttoexternalactorsoranotherexternalsystemOutputmessagesbasedonanindividualobjectareusuallypartofmethodsofthatclassobjectToreportonallobjectswithinaclass,class-levelmethodisusedthatworksonentireclassSystemsAnalysisandDesigninaChangingWorld,4thEdition26TableofSystemOutputsBased

onOOMessages(Figure14-12)SystemsAnalysisandDesigninaChangingWorld,4thEdition27DesigningReports,Statements,andTurnaroundDocumentsPrintedversuselectronicTypesofoutputreportsDetailedSummaryExceptionExecutiveInternalversusexternalGraphicalandmultimediapresentationSystemsAnalysisandDesigninaChangingWorld,4thEdition28RMOSummaryReportwith

DrillDowntotheDetailedReportSystemsAnalysisandDesigninaChangingWorld,4thEdition29SampleBarChartandPieChartReportsSystemsAnalysisandDesigninaChangingWorld,4thEdition30FormattingReportsWhatisobjectiveofreport?Whoistheintendedaudience?Whatismediaforpresentation?AvoidinformationoverloadFormatconsiderationsincludemeaningfulheadings,dateofinformation,datereportproduced,pagenumbersSystemsAnalysisandDesigninaChangingWorld,4thEdition31DesigningIntegrityControlsMechanismsandproceduresbuiltintoasystemtosafeguarditandinformationcontainedwithinIntegritycontrolsBuiltintoapplicationanddatabasesystemtosafeguardinformationSecuritycontrolsBuiltintooperatingsystemandnetworkSystemsAnalysisandDesigninaChangingWorld,4thEdition32ObjectivesofIntegrityControlsEnsurethatonlyappropriateandcorrectbusinesstransactionsoccurEnsurethattransactionsarerecordedandprocessedcorrectlyProtectandsafeguardassetsoftheorganizationSoftwareHardwareInformationSystemsAnalysisandDesigninaChangingWorld,4thEdition33PointsofSecurityandIntegrityControlsSystemsAnalysisandDesigninaChangingWorld,4thEdition34InputIntegrityControlsUsedwithallinputmechanismsAdditionallevelofverificationtohelpreduceinputerrorsCommoncontroltechniquesFieldcombinationcontrolsValuelimitcontrolsCompletenesscontrolsDatavalidationcontrolsSystemsAnalysisandDesigninaChangingWorld,4thEdition35DatabaseIntegrityControlsAccesscontrols=managementuserDataencryptionTransactioncontrols=transactionlogUpdatecontrolsBackupandrecoveryprotectionSystemsAnalysisandDesigninaChangingWorld,4thEdition36OutputIntegrityControlsEnsureoutputarrivesatproperdestinationandiscorrect,accurate,complete,andcurrentDestinationcontrols-outputischanneledtocorrectpeopleCompleteness,accuracy,andcorrectnesscontrolsAppropriateinformationpresentinoutputSystemsAnalysisandDesigninaChangingWorld,4thEdition37IntegrityControlstoPreventFraudThreeconditionsarepresentinfraudcasesPersonalpressure,suchasdesiretomaintainextravagantlifestyleRationalizations,including“Iwillrepaythismoney〞or“Ihavethiscoming〞Opportunity,suchasunverifiedcashreceiptsControloffraudrequiresbothmanualproceduresandcomputerintegritycontrolsSystemsAnalysisandDesigninaChangingWorld,4thEdition38FraudRisksandPreventionTechniquesSystemsAnalysisandDesigninaChangingWorld,4thEdition39DesigningSecurityControlsSecuritycontrolsprotectassetsoforganizationfromallthreatsExternalthreatssuchashackers,viruses,worms,andmessageoverloadattacksSecuritycontrolobjectivesMaintainstable,functioningoperatingenvironmentforusersandapplicationsystems(24x7)Protectinformationandtransactionsduringtransmissionoutsideorganization(publiccarriers)SystemsAnalysisandDesigninaChangingWorld,4thEdition40SecurityforAccesstoSystemsUsedtocontrolaccesstoanyresourcemanagedbyoperatingsystemornetworkUsercategoriesUnauthorizeduser–noauthorizationtoaccessRegistereduser–authorizedtoaccesssystemPrivilegeduser–authorizedtoadministratesystemOrganizedsothatallresourcescanbeaccessedwithsameuniqueID/passwordcombinationSystemsAnalysisandDesigninaChangingWorld,4thEdition41UsersandAccessRolesto

ComputerSystemsSystemsAnalysisandDesigninaChangingWorld,4thEdition42ManagingUserAccessMostcommontechniqueisuserID/passwordAuthorization–Isuserpermittedtoaccess?Accesscontrollist–userswithrightstoaccessAuthentication–Isuserwhotheyclaimtobe?Smartcard–computer-readableplasticcardwithembeddedsecurityinformationBiometricdevices–keystrokepatterns,fingerprinting,retinalscans,voicecharacteristicsSystemsAnalysisandDesigninaChangingWorld,4thEdition43DataSecurityDataandfilesthemselvesmustbesecureEncryption–primarysecuritymethodAlteringdatasounauthorizeduserscannotviewDecryptionAlteringencrypteddatabacktoitsoriginalstateSymmetrickey–samekeyencryptsanddecryptsAsymmetrickey–differentkeydecryptsPublickey–publicencrypts;privatedecryptsSystemsAnalysisandDesigninaChangingWorld,4thEdition44SymmetricKeyEncryptionSystemsAnalysisandDesigninaChangingWorld,4thEdition45AsymmetricKeyEncryptionSystemsAnalysisandDesigninaChangingWorld,4thEdition46DigitalSignaturesandCertificatesEncryptionofmessagesenablessecureexchangeofinformationbetweentwoentitieswithappropriatekeysDigitalsignatureencryptsdocumentwithprivatekeytoverifydocumentauthorDigitalcertificateisinstitution’snameandpublickeythatisencryptedandcertifiedbythirdpartyCertifyingauthorityVeriSignorEquifaxSystemsAnalysisandDesigninaChangingWorld,4thEdition47UsingaDigitalCertificateSystemsAnalysisandDesigninaChangingWorld,4thEdition48Secure