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Exploring Information System Development

Exploring Information System Development

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  • 1. Chapter 12Exploring Information SystemDevelopmentDiscovering Computers 2012 Your Interactive Guide to the Digital World
  • 2. Objectives Overview Discuss the importance of project management,Define system development Identify the guidelines for feasibility assessment, and list the system system development documentation, and data development phases and information gathering techniques Explain the activities Discuss the purpose of the Describe the various tools performed in the planning activities performed in the used in process modeling phase analysis phaseSee Page 619 2 Discovering Computers 2012: Chapter 12for Detailed Objectives
  • 3. Objectives Overview Recognize the develop Describe the various Explain the activities programs activity is tools used in object performed in the part of system modeling design phase development Discuss the purpose of Discuss the activities the activities performed in the performed in the implementation phase operation, support, and security phaseSee Page 619 3 Discovering Computers 2012: Chapter 12for Detailed Objectives
  • 4. What is System Development? System development is a set of activities used to build an information system An information system (IS) is a System development A system is a set of collection of activities are grouped components that hardware, software, into phases, interact to achieve a data, people, and collectively called the common goal procedures that work system development together to produce life cycle (SDLC) quality informationPage 620 Discovering Computers 2012: Chapter 12 4
  • 5. What is System Development?Pages 620 – 621 Discovering Computers 2012: Chapter 12 5Figure 12-1
  • 6. What is System Development?• System development should follow three general guidelines: Group activities or tasks into phases Involve users Define standardsPage 621 Discovering Computers 2012: Chapter 12 6
  • 7. What is System Development?• System development should involve representatives from each department in which the proposed system will be usedPage 622 Discovering Computers 2012: Chapter 12 7Figure 12-2
  • 8. What is System Development?• Project management is the process of planning, scheduling, and then controlling the activities during system development• To plan and schedule a project efficiently, the project leader identifies: Required Time estimates Project scope activities for each activity Activities that Cost estimates Order of can take place at for each activity activities the same timePage 623 Discovering Computers 2012: Chapter 12 8
  • 9. What is System Development? A popular tool used to plan and schedule the time relationships among project activities is a Gantt chartPage 623 Discovering Computers 2012: Chapter 12 9Figure 12-3a
  • 10. What is System Development? A PERT chart also can be used for planning andscheduling timePage 624 Discovering Computers 2012: Chapter 12 10Figure 12-3b
  • 11. What is System Development?• Feasibility is a measure of how suitable the development of a system will be to the organization Operational Schedule Technical Economic feasibility feasibility feasibility feasibilityPages 624 - 625 Discovering Computers 2012: Chapter 12 11
  • 12. What is System Development?• Documentation is the collection and summarization of data and information – A project notebook contains all documentation for a single project• Users and IT professionals refer to existing documentation when working with and modifying current systemsPage 625 Discovering Computers 2012: Chapter 12 12
  • 13. What is System Development?• During system development, members of the project team gather data and information using several techniques Review Observe Surveydocumentation Interview JAD Sessions ResearchPages 625 – 626 Discovering Computers 2012: Chapter 12 13Figure 12-4
  • 14. Who Initiates a SystemDevelopment Project?A user may request a new or modified systemOrganizations may want to improve hardware, software, or othertechnologySituations beyond an organization’s control might require a changeManagement might mandate a changeA user may request a new or modified information system using a requestfor system services or a project requestPage 626 Discovering Computers 2012: Chapter 12 14
  • 15. Who Initiates a SystemDevelopment Project?Page 627 Discovering Computers 2012: Chapter 12 15Figure 12-5
  • 16. Planning Phase• The planning phase for a project begins when the steering committee receives a project request• Four major activities are performed: Review and Form a project Prioritize the Allocate approve the development project requests resources project requests teamPage 628 Discovering Computers 2012: Chapter 12 16
  • 17. Analysis Phase• The analysis phase consists of two major activities: Conduct a preliminary Perform detailed investigation analysis • Determines and • Study how the current defines the exact system works nature of the problem • Determine the users’ or improvement wants, needs, and • Interview the user who requirements submitted the request • Recommend a solutionPages 629 - 631 Discovering Computers 2012: Chapter 12 17
  • 18. Analysis PhasePage 630 Discovering Computers 2012: Chapter 12 18Figure 12-6
  • 19. Analysis Phase• Process modeling (structured analysis and design) is an analysis and design technique that describes processes that transform inputs into outputs Entity- Data flow relationship diagrams diagrams Project dictionaryPage 631 Discovering Computers 2012: Chapter 12 19
  • 20. Analysis Phase • An entity-relationship diagram (ERD) is a tool that graphically shows the connections among entities in a system • Entities are objects in the system that have dataPage 632 Discovering Computers 2012: Chapter 12 20Figure 12-7
  • 21. Analysis Phase • A data flow diagram (DFD) is a tool that graphically shows the flow of data in a system – Data flows – Processes – Data stores – SourcesPage 632 Discovering Computers 2012: Chapter 12 21Figure 12-8
  • 22. Analysis Phase• The project dictionary contains all the documentation and deliverables of a project• Structured English is a style of writing that describes the steps in a processPage 633 Discovering Computers 2012: Chapter 12 22Figure 12-9
  • 23. Analysis Phase A decision table is a table that lists a variety of conditions and the actions that correspond to each condition A decision tree also shows conditions and actions, but it shows them graphicallyPage 633 Discovering Computers 2012: Chapter 12 23
  • 24. Analysis Phase Decision table Decision treePage 633 Discovering Computers 2012: Chapter 12 24Figures 12-10 – 12-11
  • 25. Analysis Phase• The data dictionary stores the data item’s name, description, and other details about each data itemPage 634 Discovering Computers 2012: Chapter 12 25Figure 12-12
  • 26. Analysis Phase• Object modeling combines the data with the processes that act on that data into a single unit, called an object• UML (Unified Modeling Language) has been adopted as a standard notation for object modeling and development – UML includes 13 different diagrams – Two diagrams include: Use case Class diagram diagramPage 634 Discovering Computers 2012: Chapter 12 26
  • 27. Analysis Phase • A use case diagram graphically shows how actors (users) interact with the information system • Diagrams are considered easy to understandPage 634 Discovering Computers 2012: Chapter 12 27Figure 12-13
  • 28. Analysis Phase • A class diagram graphically shows classes and subclasses in a system • Each class can have one or more subclasses • Subclasses use inheritance to inherit methods and attributes of higher levelsPage 635 Discovering Computers 2012: Chapter 12 28Figure 12-14
  • 29. Analysis Phase• The system proposal assesses the feasibility of each alternative solution• The steering committee discusses the system proposal and decides which alternative to pursue Packaged Custom Outsourcing software softwarePages 635 - 636 Discovering Computers 2012: Chapter 12 29
  • 30. Design Phase• The design phase consists of two major activities Develop all of the Acquire hardware details of the new and software or modified information systemPage 638 Discovering Computers 2012: Chapter 12 30
  • 31. Design Phase• To acquire the necessary hardware and software: Solicit vendor Make a decision• Use research proposals • Various techniques techniques such as are used to e-zines • RFQ, RFP, or RFI is determine the best • Systems analyst sent to potential proposal makes vendors or VARs recommendation to steering committee Identify technical Test and evaluate specifications vendor proposalsPages 638 - 640 Discovering Computers 2012: Chapter 12 31
  • 32. Design Phase• The next step is to develop detailed design specifications – Sometimes called a physical design Input and Database Program output design design designPage 640 Discovering Computers 2012: Chapter 12 32
  • 33. Design Phase• Systems analysts typically develop two types of designs for each input and output Mockup Layout chartPage 641 Discovering Computers 2012: Chapter 12 33Figures 12-18 – 12-19
  • 34. Design Phase• A prototype (proof of concept) is a working model of the proposed system – Prototypes have inadequate or missing documentation – Users tend to embrace the prototype as a final system – Should not eliminate or replace activitiesPages 641 - 642 Discovering Computers 2012: Chapter 12 34
  • 35. Design Phase• Computer-aided software engineering (CASE) tools are designed to support one or more activities of system development• CASE tools sometimes contain the following tools: Project Graphics Prototyping repository Quality Code Housekeeping assurance generatorPage 642 Discovering Computers 2012: Chapter 12 35
  • 36. Design PhasePage 642 Discovering Computers 2012: Chapter 12 36Figure 12-20
  • 37. Design Phase• Many people should review the detailed design specifications• An inspection is a formal review of any system development deliverable – A team examines the deliverables to identify errorsPage 642 Discovering Computers 2012: Chapter 12 37
  • 38. Implementation Phase• The purpose of the implementation phase is to construct the new or modified system and then deliver it Install and Convert to Develop test the new Train users the new programs system systemPage 643 Discovering Computers 2012: Chapter 12 38
  • 39. Implementation Phase• The program development life cycle follows these steps: • Analyze the requirements 1 2 • Design the solution 3 • Validate the design 4 • Implement the design 5 • Test the solution 6 • Document the solutionPage 643 Discovering Computers 2012: Chapter 12 39
  • 40. Implementation Phase• Various tests should be performed on the new system Integration Acceptance Unit test Systems test test test • Verifies that • Verifies that • Verifies that • Checks the each all programs an new system individual in an application to ensure program or application works with that it works object works work other with actual by itself together applications data properlyPage 644 Discovering Computers 2012: Chapter 12 40
  • 41. Implementation Phase• Training involves showing users exactly how they will use the new hardware and software in the system – One-on-one sessions – Classroom-style lectures – Web-based trainingPage 644 Discovering Computers 2012: Chapter 12 41Figure 12-21
  • 42. Implementation Phase• One or more of four conversion strategies can be used to change from the old system to the new systemPages 644 – 645 Discovering Computers 2012: Chapter 12 42Figure 12-22
  • 43. Operation, Support, and Security Phase• The purpose of the operation, support, and security phase is to provide ongoing assistance for an information system and its users after the system is implemented Perform Monitor Assess system maintenance system security activities performancePages 645 - 646 Discovering Computers 2012: Chapter 12 43
  • 44. Operation, Support, and Security Phase• A computer security plan should do the following: For each risk, Identify all identify the Identify all security risks safeguards that information that may cause exist to detect, assets of an an information prevent, and organization asset loss recover from a lossPage 646 Discovering Computers 2012: Chapter 12 44
  • 45. Video: Create a Hidden Operating System CLICK TO START Discovering Computers 2012: Chapter 12 45
  • 46. Summary System Guidelines for development system phases development Activities Activities that occur performed during during system each system development development phasePage 647 Discovering Computers 2012: Chapter 12 46
  • 47. Chapter 12Exploring Information SystemDevelopmentDiscovering Computers 2012 Your Interactive Guide to the Digital World Chapter 12 Complete