MELJUN CORTES SAD ch17

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MELJUN CORTES SAD ch17

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MELJUN CORTES SAD ch17

  1. 1. Chapter 17Successfully ImplementingThe Information System Systems Analysis and DesignMELJUN CORTES
  2. 2. Major Topics • Client/server computing • Network types • Groupware • Training • Security • Organizational metaphors • EvaluationKendall & © 2005 PearsonKendall Prentice Hall 17-2
  3. 3. Implementation • Implementation is the process of assuring that the information system is operational. • Well-trained users are involved in its operation.Kendall & © 2005 PearsonKendall Prentice Hall 17-3
  4. 4. Distributed Systems • Distributed systems use telecommunications technology and database management to interconnect people. • A distributed system includes work stations that can communicate with each other and with data processors. • The distributed system may have different configurations of data processors.Kendall & © 2005 PearsonKendall Prentice Hall 17-4
  5. 5. Client/Server Computing • The client/server (C/S) model consists of clients request and the server fulfillment of the request. • The client is a networked computer, running a GUI interface. • A file server stores programs and data • A print server receives and stores files to be printed.Kendall & © 2005 PearsonKendall Prentice Hall 17-5
  6. 6. Advantages andDisadvantages ofClient/Server • The advantages of a client/server system are greater computer power and greater opportunity to customize applications. • The disadvantages of a client/server system are greater expense and applications must be written as two separate software components running on separate machines.Kendall & © 2005 PearsonKendall Prentice Hall 17-6
  7. 7. Network Types Standard types of networks include the wide-area network (WAN), the local area network (LAN), and the wireless local area network (WLAN).Kendall & © 2005 PearsonKendall Prentice Hall 17-7
  8. 8. Wireless Local Area Network(WLAN) • Called Wi-Fi, wireless fidelity • Can include encryption wired equivalent privacy (WEP) for security • Cheap to set up • FlexibleKendall & © 2005 PearsonKendall Prentice Hall 17-8
  9. 9. Wireless Local Area Network(WLAN) (Continued) • Concerns: • Security. • Signal integrity. • Wi-Fi networks are prone to interference from systems operating nearby in the same frequency spectrum. • Bluetooth is suitable for personal networks and can include computers, printers, handheld devices, phones, keyboards, mice and household appliances.Kendall & © 2005 PearsonKendall Prentice Hall 17-9
  10. 10. Network Configurations There are four types of network configurations: • Hierarchical. • Star. • Ring. • Bus.Kendall & © 2005 PearsonKendall Prentice Hall 17-10
  11. 11. Hierarchical • A hierarchical network will contain several levels, with a host at the top. • A host computer has many smaller computers that only communicate with the host, not with each other. • The host controls all other nodes. • Computers on the same level do not communicate with each other.Kendall & © 2005 PearsonKendall Prentice Hall 17-11
  12. 12. Star The host computer can communicate with other computers that can communicate with each other only through the host.Kendall & © 2005 PearsonKendall Prentice Hall 17-12
  13. 13. Ring • All computers communicate with each other, passing messages around the ring. • There is no central computer. • Each node is in direct communication with its neighbor.Kendall & © 2005 PearsonKendall Prentice Hall 17-13
  14. 14. Bus • A single central cable is used to connect all the computers. • It has a single, central cable that serves as the only communication path connecting several different devices.Kendall & © 2005 PearsonKendall Prentice Hall 17-14
  15. 15. Network Models Several models are available for designing a network: • A network decomposition diagram provides an overview of the system and is drawn first. • A hub connectivity shows how the major hubs are connected and is drawn second • A workstation connectivity diagram shows the details of connecting the workstations.Kendall & © 2005 PearsonKendall Prentice Hall 17-15
  16. 16. Network Decomposition and HubConnectivity Diagram SymbolsKendall & © 2005 PearsonKendall Prentice Hall 17-16
  17. 17. Network Decomposition DiagramKendall & © 2005 PearsonKendall Prentice Hall 17-17
  18. 18. Hub Connectivity DiagramKendall & © 2005 PearsonKendall Prentice Hall 17-18
  19. 19. Workstation Connectivity DiagramKendall & © 2005 PearsonKendall Prentice Hall 17-19
  20. 20. Groupware Groupware is software that supports people working together in an organization.Kendall & © 2005 PearsonKendall Prentice Hall 17-20
  21. 21. Groupware Functions Groupware helps group members to: • Schedule and attend meetings. • Share data. • Create and analyze documents. • Communicate in unstructured communication via email. • Hold group conferences. • Perform departmental-level image management. • Manage and monitor workflow.Kendall & © 2005 PearsonKendall Prentice Hall 17-21
  22. 22. Advantages of DistributedSystems Advantages of distributed systems are: • Data are stored where it does not affect the processing of online real-time transaction processing. • Data are stored using less expensive media at local sites. • Lowered equipment costs.Kendall & © 2005 PearsonKendall Prentice Hall 17-22
  23. 23. Advantages of DistributedSystems Advantages of distributed systems are (continued): • Provide flexibility in choice of equipment manufacturer. • Initially less expensive than large systems.Kendall & © 2005 PearsonKendall Prentice Hall 17-23
  24. 24. Disadvantages of DistributedSystems Disadvantages of distributed systems are: • Difficulty in achieving reliable system. • Security may be breached. • The relationships between subsystems must not be ignored. • Choosing the wrong level of computing to support.Kendall & © 2005 PearsonKendall Prentice Hall 17-24
  25. 25. Training • New system training must be performed. • Analysts must consider: • Who needs to be trained. • Who will train them. • Objectives of training. • Methods of instruction to be used. • Sites. • Materials.Kendall & © 2005 PearsonKendall Prentice Hall 17-25
  26. 26. Sources of Training Possible sources of training for users of information systems include: • Vendors. • Systems analysts. • External paid trainers. • In-house trainers. • Other system users.Kendall & © 2005 PearsonKendall Prentice Hall 17-26
  27. 27. Concerns for Training Objectives,Method, Sites and MaterialsKendall & © 2005 PearsonKendall Prentice Hall 17-27
  28. 28. Conversion Strategies Five conversion strategies are: • Direct changeover. • Parallel conversion. • Gradual or Phased conversion. • Modular prototype conversion. • Distributed conversion.Kendall & © 2005 PearsonKendall Prentice Hall 17-28
  29. 29. Conversion StrategiesKendall & © 2005 PearsonKendall Prentice Hall 17-29
  30. 30. Security • Security considerations must be included when implementing a system. • These include: • Physical security. • Logical security. • Behavioral security.Kendall & © 2005 PearsonKendall Prentice Hall 17-30
  31. 31. Security (Continued) • Physical security is controlling access to physical computer resources. • Logical security is controlling software access. • Behavioral security is building procedures to prevent persons from misusing computer hardware and software.Kendall & © 2005 PearsonKendall Prentice Hall 17-31
  32. 32. Web Security Precautions used to protect the computer network from both internal and external Web security threats include: • Virus protection software. • Email filtering products. • URL filtering products. • Firewalls, gateways, and virtual private networks.Kendall & © 2005 PearsonKendall Prentice Hall 17-32
  33. 33. Web Security • Precautions used to protect the computer network from both internal and external Web security threats include (continued): • Intrusion detection products. • Vulnerability management products. • Security technologies such as secure socket layering (SSL) for authentication. • Encryption technologies. • Public key infrastructure (PKI) use and obtaining a digital certificate.Kendall & © 2005 PearsonKendall Prentice Hall 17-33
  34. 34. Ecommerce PrivacyGuidelines • Privacy is essential to ecommerce. • Some privacy policy guidelines are: • Start with a corporate policy on privacy. • Only ask for information required to complete the transaction. • Make it optional for customers to fill out personal information on the Web site.Kendall & © 2005 PearsonKendall Prentice Hall 17-34
  35. 35. Ecommerce PrivacyGuidelines • Some privacy policy guidelines are (continued): • Use sources that allow you to obtain anonymous information about classes of customers. • Be ethical in data gathering.Kendall & © 2005 PearsonKendall Prentice Hall 17-35
  36. 36. Other Conversion Considerations • Ordering equipment • Ordering external supplies, such as toner cartridges, paper, preprinted forms and so on • Appointing a manager to supervise the preparation of the installation site • Planning, scheduling, and supervising IT personnel who convert files and databasesKendall & © 2005 PearsonKendall Prentice Hall 17-36
  37. 37. Evaluation Approaches Several evaluation approaches can be used: • Cost-benefit analysis. • Revised decision evaluation approach. • User involvement evaluations. • The information system utility approach.Kendall & © 2005 PearsonKendall Prentice Hall 17-37
  38. 38. Organizational Metaphors Organizational metaphors may be used to assist in a successful implementation of a new system.Kendall & © 2005 PearsonKendall Prentice Hall 17-38
  39. 39. Organizational Metaphors(Continued) • Zoo • Society • Jungle • Family • War • Organism • Journey • Game • MachineKendall & © 2005 PearsonKendall Prentice Hall 17-39
  40. 40. Organizational Metaphors andTypes of Information SystemsKendall & © 2005 PearsonKendall Prentice Hall 17-40
  41. 41. Interpreting OrganizationalMetaphors • Zoo indicates success is likely with traditional MIS systems and decision support systems. • Jungle indicates success is likely with decision support systems, cooperative systems, competitive systems, and executive information systems.Kendall & © 2005 PearsonKendall Prentice Hall 17-41
  42. 42. Interpreting OrganizationalMetaphors (Continued) • War indicates success is likely with competitive systems. • Journey indicates success is likely with cooperative systems. • Machine indicates success is likely with traditional MIS systems and expert systems/artificial intelligence.Kendall & © 2005 PearsonKendall Prentice Hall 17-42
  43. 43. Interpreting OrganizationalMetaphors (Continued) • Society indicates success is likely with traditional MIS systems and decision support systems. • Family indicates success is likely with traditional MIS systems and decision support systems.Kendall & © 2005 PearsonKendall Prentice Hall 17-43
  44. 44. Interpreting OrganizationalMetaphors (Continued) • Organism indicates success is likely with decision support systems, expert systems/artificial intelligence, cooperative systems, competitive systems, and executive information systems.Kendall & © 2005 PearsonKendall Prentice Hall 17-44
  45. 45. Interpreting OrganizationalMetaphors (Continued) • Game indicates success is likely with expert systems/artificial intelligence, cooperative systems, competitive systems, and executive information systems.Kendall & © 2005 PearsonKendall Prentice Hall 17-45
  46. 46. Information System UtilityEvaluation • The information system utility framework is a way to evaluate a new system based on utilities of: • Possession. • Form. • Place. • Time. • Actualization. • Goal.Kendall & © 2005 PearsonKendall Prentice Hall 17-46
  47. 47. Information System UtilityEvaluation (Continued) • Possession utility answers the question of who should receive output. • Goal utility answers the why of information systems by asking whether the output has value in helping the organization achieve its objectives. • Place utility answers the question of where information is distributed.Kendall & © 2005 PearsonKendall Prentice Hall 17-47
  48. 48. Information System UtilityEvaluation (Continued) • Form utility answers the question of what kind of output is distributed to the decision maker. • Time utility answers the question of when information is delivered. • Actualization utility involves how the information is introduced and used by the decision maker.Kendall & © 2005 PearsonKendall Prentice Hall 17-48
  49. 49. Web Site Evaluation • Corporate Web sites should be evaluated. • The following is a list of key things to learn about the Web site visitors: • Know how often the Web site is visited. • Learn details about specific pages on the site. • Find out demographic and other information about Web site visitors.Kendall & © 2005 PearsonKendall Prentice Hall 17-49
  50. 50. Web Site Evaluation • The following is a list of key things to learn about the Web site visitors (continued): • Discover if visitors can properly fill out the Web forms. • Find out who is referring Web site visitors to the client’s Web site. • Determine what browsers visitors are using. • Find out if the client’s Web site visitors are interested in advertising the Web site.Kendall & © 2005 PearsonKendall Prentice Hall 17-50

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