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

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

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

Sylnovie Merchant, Ph.D. MIS 161 Spring 2005 Type I (Iterative) Life CycleRequirementsDefinitionRequirementsDefinitionPrototypeTrainingPrototypeTrainingProjectPlanningProjectPlanning RapidAnalysisRapidAnalysis DatabaseDesignDatabaseDesign DesignPrototypeDesignPrototype GeneratePrototypeGeneratePrototype TestPrototypeTestPrototype Acceptable?Acceptable? ImplementSystemImplementSystem MaintainSystemMaintainSystem NoNo YesYes

Sylnovie Merchant, Ph.D. MIS 161 Spring 2005 Type II (Throwaway) Life CycleRequirementsDefinitionRequirementsDefinition AnalysisAnalysis DesignPrototypeDesignPrototype CodePrototypeCodePrototype TestPrototypeTestPrototype Acceptable?Acceptable? Code Final System System Test Final System System Acceptable?Acceptable? Implement Final System System Maintain Final System System YesYes NoNo NoNo YesYes

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

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

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

Sylnovie Merchant, Ph.D. MIS 161 Spring 2005 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 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

Designing the User Interface

Sylnovie Merchant, Ph.D. MIS 161 Spring 2005 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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