งานนำเสนอเรื่อง: "Introduction to System Development"— ใบสำเนางานนำเสนอ:
1Introduction to System Development Introduction : Have you ever seen newspaper headlinessimilar to the following ?IRS Computer Audit Record Number of Tax ReturnsComputer Skills Needed for Today’s JobsComputer Failure Halts Shuttle LaunchWall Street Computer Handle Growing Stock TradingVolumeNewspaper headlines are not our only view of today’swidespread use of computers. The use of computers in today’sworld is commonplace. We take computers for granted andexpect them to work perfectly; that is, to be reliable, fast,accurate, and easy to use.
2Systems and procedures As it conducts its business, a company performs manyfunctions in a specified manner.A procedure is defined as the series of steps followed ina regular, specified order to accomplish one end result.One procedure for company is the writing of employeepayroll checks, and a second procedure is the filling ofcustomer orders.A system is defined as a set of procedures used toaccomplish specific results.
4Example Systems Student Record Management System Library Loan System A computerised system that manages information concerning courses on offer at Brookes and Students registered to take one of more of those courses.Library Loan SystemA computerised system that manages the issuing and recall of library books.Car Park ManagementA paper (form)-based system for managing the allocation of parking spaces to visitors
5Examples (cont.) Traffic Management System Chemical Process Control A system of interconnected components (roundabouts, traffic light, calming devices) to manage the flow of traffic through …Chemical Process ControlA system based on feedback and control to manage the manufacturing of ….The Respiratory SystemThe physiological system which enables the act or process of breathing in animals
6Key IdeasMany failed systems were abandoned because analysts tried to build wonderful systems without understanding the organization.The primarily goal is to create value for the organization.
7Simple system model Data processing Information input - manual output - computerize- knowledge
8System inputs are called data, and system output are called Information.Data : defined as raw facts and figures, are the raw materialsof the system.Information : defined as data processed for someone’s use,represents the finished goods of the system.The objective of processing is to ensure the validity of theincoming data and to convert valid data into timely andaccurate information.A system may be called an information system, an application,or an application system.
9Information system components PeopleProcedureHardwareSoftwareFilesDataInformation
10People - include both management and end users Procedures - the tasks performed by all the peopleHardware - computers, scanners, printer, andnoncomputer equipmentSoftware - system software- DOS, Windows, and UNIX- application softwareFiles - the retained data is stored in files anddatabases on computerAn information system is the collection of data, people,procedures, hardware, software, files, and information requiredto accomplish an organized set of functions.
12Wisdom "Wisdom is not a product of schooling but of the lifelong attempt to acquire it.“Albert Einstein
13Business information systems Each business organization sells specific products orservices and has specific goals, methods, and informationsystem requirements that are set in the organization’sunderlying corporate culture. A company’s corporateculture is the set of beliefs, rules, traditions, values, andattitudes that give a company its atmosphere or personalityand govern its way of doing business. In order to create aneffective information system for a company, you mustunderstand the information system’s requirements and thecompany’s goals, methods, and corporate culture.
14Although there are a variety of types of business organizations in operation in the world today, companiesare generally classified into two basic types:Industrial, or production-oriented companies, whichproduce, sell, and distribute goodsservice companies, which sell and distribute goods,services, or informationThe total business information system of a companynormally consists of a series of subsystems, many of whichare common to all business organizations.
16Four characteristics of business information systems help to define their complexity.1. Information systems are related to otherinformation systems.2. A boundary between two systems is where onesystem ends and the other system begins.3. In addition to the common business informationsystems, there are many specialized information systems.At a school, specialized information systems handle classregistration, class room scheduling, student grading, studentloans, and transcript processing.
174. Large and small companies in the same industry have significant differences in their information systemrequirements.
18Types of information systems The types of information systems that use a computerfall into six broad categories:Operation systems (transaction processing system)Management information systems (MIS)Decision support systems (DSS)Executive information systems (EIS)Expert systems (ES) or Artificial intelligence (AI)Office automation systems (OAS)The integration of information systems
19Organization levelsInformation is a company asset, as are employee,equipment and buildings, materials, and money.Information systems exist to provide this informationasset to people in the organization. Informationrequirements vary widely, depending on the person’sresponsibilities and position within the company. Allcompanies organize in the way shown in figure;operational personnel report to lower management, whoreport to middle management, who report to topmanagement.
21Organization Responsibility Decision Information Systems Level Making RequirementsTop Develop long-range Unstructured Executive information systemsManagement goals, plans and MIS summariesstrategies Decision support systemsOffice automation systemsMiddle Develop short-range Semi-structured MIS summaries and exceptionsManagement goals, plans, and Decision support systemstactics Office automation systemsLower Develop day-to-day Structured Operational systems detailsManagement plans and supervise Some MIS summaries andoperational personnel exceptionsOperational Perform routine Structured Operational systems detailsPersonnel function Expert systems
23Integrating Technologies for Systems 1. Ecommerce Applications and Web Systems- Increasing user awareness of the availabilityof a service, product, industry, person, orgroup.- The possibility of 24-hour access for users.2. Enterprise Systems- Service-oriented architecture (SOA)- Enterprise resource planning (ERP)3. Systems for Wireless and Mobile Devices4. Open Source Software (OSS)
24ES, DSS, MIS KWS, OAS TPS ESS GDSS CSCWS Wireless Systems Enterprise SystemsTPSEcommerce and Web Systems24
25Information systems department The structure of the information systems departmentvaries among companies, as does its name and itsplacement within the organization.DirectorInformationSystemsManagerTechnicalSupportManagerInformationCenterManagerApplicationsOperationsManager
26Maxim The organization that has the best information, knows where to find it,and can utilize it the quickest wins.
27Data Quality Factors Accuracy Timeliness Consistency Whether the value of each item of data is correctTimelinessWhether the data are up-to-dateConsistencyWhether the data in one part of the database have a common, appropriate set of controls to related concepts stored elsewhere
28Data Quality Factors Transparency of meaning Availability Whether the context for the data is clearly and commonly understood by all those with a legitimate interestAvailabilityWhether the people who need the data can actually access it
29System definition : set of interrelated and interacting elements that work together toaccomplish specific purposes.structure : inputs, processes, outputs, feedback,environment, decision maker.subsystem : a system within a system.system performance : effectiveness (doing the rightthing),efficiency (doing thething right), cost,complexity, and control.
30Effectiveness and Efficiency Two Major Classes of PerformanceMeasurementEffectiveness is the degree to which goalsare achieved Doing the right thing!Efficiency is a measure of the use of inputs(or resources) to achieve outputsDoing the thing right!
32Inputs are elements that enter the system Processes convert or transform inputs intooutputsOutputs describe finished products orconsequences of being in the systemFeedback is the flow of information from theOutput to the decision maker, who may modifythe inputs or the processes (closed loop)The Environment contains the elements that lieoutside but impact the system's performance
34Modeling a system Model = abstraction of reality - narrative models - physical models- schematic models- mathematical modelsF = X2 + Y2
35Systems Analysis and Design: What is it? Systems analysis: the systematic study of the information needs and problems of some organizational domain in order to recommend improvements and specify the business requirements for the solution.Systems design: the specification of a technical, computer-based solution for the business requirements identified in a systems analysis
36Systems Analysis and Design: Why is it? Many information systems fail, because of:lack of reliabilitylack of usabilitynot what the users wantedincompatible with other systemsSA&D addresses all but the first problemSA&D is also long-term approach to ensure the overall effectiveness of IT in the organization
37Systems Analysis and Design: Who is it? A systems analyst studies the informationproblems and needs of an organization todetermine how to best solve the problems andaccomplish improvements using informationtechnology.improved business processesimproved information systemsimproved computer applications
38Systems Analysis and Design: Who is it? Roles of the Systems Analyst :Consultant (outsider)Supporting Expert (insider)Agent of Change (shaker)38
39Systems Analysis and Design: Where is it? Not just for businesses!non-profit organizationsgovernment agencieseducational institutions
40Key Ideas The systems analyst is a key person analyzing the business, identifying opportunities forimprovement, and designing informationsystems to implement these ideas.It is important to understand and developthrough practice the skills needed tosuccessfully design and implement newinformation systems.
41Qualities and Skills of a Systems Analyst AnalyticalTechnicalManagementInterpersonal
42Required skills and background Working Knowledge of Information Systems andTechnologyComputer Programming Experience andExpertiseGeneral Business KnowledgeProblem-Solving SkillsInterpersonal Communications SkillsInterpersonal Relations SkillsFlexibility and AdaptabilityCharacter and EthicsSystems Analysis and Design Skills
43Who is system analyst?User System analyst Programmer
45General System Model of the Firm ENVIRONMENTStandardsand dataInformationInformationDecisionsProcessorInformationManagementresourcesPhysicalresourcesPhysicalresourcesInputprocessTransformationresourcesOutput
51Who Are the Players in Systems Development? User(s)Business manager(s)Steering committeeApplication programmersSystem programmersDatabase, network, and other technologyspecialistsSecurity / auditing staffHuman factors expertsDocumentation specialists