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Prototyping

MIS 161 Systems Development Life Cycle II Lecture 3: Remember Prototyping? Data Storage Interface Design. Prototyping. Definition. A PROTOTYPE is a model of the system It can be as simple as mock-ups of reports or screens, or as complete as software that actually does some processing.

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Prototyping

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  1. MIS 161Systems Development Life Cycle IILecture 3:Remember Prototyping?Data Storage Interface Design Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  2. Prototyping Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  3. Definition • A PROTOTYPE is a model of the system • It can be as simple as mock-ups of reports or screens, or as complete as software that actually does some processing. • Can be used as a communication tool between analyst and user. • Prototyping is the process of developing prototypes. • Prototyping strategy indicates the type of prototype used. Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  4. How is it Used? • As a methodology • As a technique/tool within the SDLC. • Some phases supported/replaced Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  5. Approaches • Type I - Iterative • becomes final system • Type II - Throwaway • used as model for final system Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  6. Type I (Iterative) Life Cycle Requirements Definition Prototype Training Project Planning Rapid Analysis Database Design Design Prototype Generate Prototype Test Prototype No Acceptable? Yes Implement System Maintain System Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  7. Type II (Throwaway) Life Cycle Requirements Definition Analysis Design Prototype Code Prototype Test Prototype No Acceptable? Yes Code Final System No Test Final System Yes Implement Final System Maintain Final System Acceptable? Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  8. Types of Prototypes • Illustrative • Mock-ups • Simulated • Looks like they work, but are simulations • Functional • Does some processing, but doesn’t store data • Evolutionary • Used to produce an operational systems Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  9. Evolutionary Prototype Levels • Level 1 (Input-Output) • printed reports and on-line screens • screen flow sequence • screen options • Level 2 (Heuristic-Learning) • updating database • basic transactions Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  10. Levels (Continued) • Level 3 (Adaptive) • working model of system • system with training wheels • no bells or whistles Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  11. Advantages • Speed • Easier for end-users to learn • System changes discovered earlier • End-user involvement (ownership) • increased user satisfaction • increased user acceptance • User-analyst communication • Early problem detection • reduced development time • reduced maintenance Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  12. Disadvantages • Poor documentation • Hard to control/manage • (Unrealistic) User expectations • time for final system • final system differences • reduced analysis Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  13. Data Storage Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  14. Data Storage Design Objectives • The objectives in the design of data storage organization are • The data must be available when the user wants to use it • The data must have integrity • It must be accurate and consistent • Efficient storage of data as well as efficient updating and retrieval Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  15. Data Storage Design Objectives • Further design objectives • The information retrieval be purposeful • The information obtained from the stored data must be in an integrated form to be useful for • Managing • Planning • Controlling • Decision making Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  16. Dimensions of Data Storage Optimization • Storage efficiency (minimizing storage space) • Speed of access (minimizing time to retrieve desired information) Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  17. Approaches to Data Storage • There are two approaches to the storage of data in a computer system • Store the data in individual files each unique to a particular application • Storage of data in a computer-based system involves building a database • A formally defined and centrally controlled store of data intended for use in many different applications Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  18. Files • A file contains groups of records used to provide information for operations, planning, management, and decision making • Files can be used for storing data for an indefinite period of time, or they can be used to store data temporarily for a specific purpose • A file can be designed and built quite rapidly, and the concerns for data availability and security are minimized • Analysts can choose an appropriate file structure according to the required processing speed of the particular application system Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  19. Relational Object-relational Object-oriented Types of Databases Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  20. Objectives of Effective Databases • The effectiveness objectives of the database include • Ensuring that data can be shared among users for a variety of applications • Maintaining data that are both accurate and consistent • Ensuring all data required for current and future applications will be readily available Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  21. Objectives of Effective Databases • Further effectiveness objectives of the database include • Allowing the database to evolve and the needs of the users to grow • Allowing users to construct their personal view of the data without concern for the way the data are physically stored Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  22. Interface Design Specifications Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  23. Interface Structure Design • Basic components of the interface • How these components work together • Windows Navigation Diagram (WND) • Depicts how the users of an application may go from window to window through menus/command buttons. Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  24. Window Navigation Diagram (WND) • Models changes of the state interface • Each state represented as a box • Transitions Return required Return not required Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  25. Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  26. Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  27. Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  28. Designing the User Interface Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  29. The User Interface • The user interface is the system which helps users' communication with the computer system and/or the application system Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  30. User Interface Design Objectives • To design a better user interface, use the following objectives: • Effectiveness as achieved through design of interfaces that allow the user to access the system in a way that is congruent with their individual needs • Efficiency as demonstrated through interfaces that increase speed of data entry, and reduce errors Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  31. User Interface Design Objectives • Further interface design objectives • User consideration as demonstrated in designing suitable interfaces, and providing appropriate feedback to users from the system • Generating usable queries • Productivity as shown through following sound principles of design for user interfaces and work spaces Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  32. Online Screen Design • Guidelines for screen design are • Keep the screen simple • Keep the screen presentation consistent • Facilitate user movement among screens • Create an attractive screen Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  33. Input Design Objectives • The quality of system input determines the quality of system output • Well-designed input objectives • Effectiveness • Accuracy • Ease of use • Consistency • Simplicity • Attractiveness Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  34. Form Design • Guidelines for good form design • Make forms easy to fill out • Ensure that forms meet the purpose for which they are designed • Design forms to assure accurate completion • Keep forms attractive Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  35. Dialog • Dialog is the communication between a person and the computer • Three key points to be considered • Meaningful communication • Minimal user action • Standard operation and consistency Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  36. Communication • Communication means that the user understands the information that is being presented • Users with less skill require a greater amount of communication • Provide easy to use help screens • Often these contain hyperlinks to other related help topics Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  37. Minimal User Action • Minimal user action is achieved by • Entering codes instead of code meanings • Enter only data that are not stored on files • Not requiring users to enter editing characters • Supplying default values on entry screens • Providing inquiry programs with short entry fields Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  38. Minimal User Action • Further key points • Providing keystrokes for selecting menu options that are normally selected using a mouse • Selecting codes from a pull-down menu on a GUI screen • Provide context-sensitive menus, displayed when the right mouse button is clicked on an object Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  39. Standard Operation • Standard operation is achieved by • Keeping header and footer information in the same locations for all screens • Using the same keystrokes to exit a program • Using the same keystrokes to cancel a transaction • Using a standard key for obtaining help Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  40. Standard Operation • Further key points • Standardized use of icons when using graphical user interface screens • Consistent use of terminology within a screen or Web site • Providing a consistent way to navigate through the dialog • Consistent font alignment, size, and color on a Web page Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  41. Tab Control Dialogue Boxes • Tab control dialog boxes are a feature of GUI design • They should have logically grouped functions on each tab • Each tab dialog box should have OK, Cancel or Apply, and perhaps Help buttons Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  42. Evaluating User Interfaces • The five useful standards in evaluating the interfaces are • The training period for users should be acceptably short • Users early in their training should be able to enter commands without thinking about them, or referring to a help menu or manual Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  43. Evaluating User Interfaces • Continued evaluation guidelines • The interface should be "seamless" so that errors are few, and those that do occur are not occurring because of poor design • Time necessary for users and the system to bounce back from errors should be short • Infrequent users should be able to relearn the system quickly Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  44. Types of Feedback • Feedback to the user is necessary in seven distinct situations: • The computer has accepted the input • The input is in the correct form • The input is not in the correct form • There will be a delay in processing • The request has been completed • The computer cannot complete the request • More detailed feedback is available Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

  45. Program Help • Program help comes in a variety of ways: • Pressing a function key, such as F1 • A GUI pull-down menu • Context-sensitive help, specific for the operation being performed • Iconic help, obtained when a cursor is left over an icon for a few seconds Sylnovie Merchant, Ph.D. MIS 161 Spring 2005

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