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CHAPTER 4: SYSTEM DESIGN - Coggle Diagram

- - - - A good user interface provides a "user-friendly" experience
      - User interface (UI) describes how users interact with a computer system, and consists of all the hardware, software, screens, menus, functions, output, and features that affect two-way communications between the user and the computer.
      - A user interface, also called a "UI" or simply an "interface,"
    - - A user interface is based on basic principles of human-computer interaction.
      - Human-computer interaction (HCI) describes the relationship between computers and people who use them to perform their jobs, like the worker.
      - HCI concepts apply to everything from PC desktops to global networks.
  - - - PRINCIPLE 1 - Understand the Business
        
        Understand the underlying business functions and how the system supports individual, departmental, and enterprise goals.
        
        Starting point : Analyse a functional decomposition diagram (FDD).
        
        An FDD can provide a checklist of user tasks that you must include in the interface design.
      - PRINCIPLE 2 - Maximize Graphical Effectiveness
        
        Studies show that people learn better visually.
        
        A well-designed interface can help users learn a new system rapidly, and be more productive.
        
        a user can display and work with multiple windows on a single screen and transfer data between programs.
      - PRINCIPLE 3 - Think Like a User
        
        Users are likely to have real-world experience with many other machines and devices that provide feedback, such as automobiles, ATM machines, and microwave ovens.
        
        Based on that experience, users will expect useful, understandable feedback from a computer system.
      - PRINCIPLE 4 - Use Models and Prototypes
        
        It is essential to construct models and prototypes for user approval.
        
        An interface designer should obtain as much feedback as possible, as early as possible.
        
        The storyboard can be created with software, or drawn freehand.
      - PRINCIPLE 5 - Focus on Usability
        
        The user interface should include all tasks, commands, and communications between users and the information system.
        
        The objective is to offer a reasonable number of choices that a user easily can comprehend.
        
        Too many options on one screen can confuse a user
      - PRINCIPLE 6 - Invite Feedback
        
        After the system is operational, it is important to monitor system usage and solicit user suggestions.
        
        You can determine if system features are being used as intended by observing and surveying users.
        
        Sometimes, full-scale operations highlight problems that were not apparent when the prototype was tested.
      - PRINCIPLE 7 - Document Everything
        
        You should document all screen designs for later use by programmers.
        
        If you are using a CASE tool or screen generator, number the screen designs and save them in a hierarchy similar to a menu tree.
        
        User-approved sketches and storyboards also can be used to document the user interface.
  - - - Facilitate the system design objectives, rather than calling attention to the interface.
      - Create a design that is easy to learn and remember.
      - Design the interface to improve user efficiency and productivity.
      - Write commands, actions, and system responses that are consistent and predictable.
    - - Clearly label all controls, buttons, and icons.
      - Select only those images that users can understand easily, and provide on-screen instructions that are logical, concise, and clear. Users become very frustrated when they see images or messages that are confusing or misleading.
      - Show all commands in a list of menu items, but dim any commands that are not currently available.
      - Make it easy to navigate or return to any level in the menu structure.
    - - Organize tasks, commands, and functions in groups that resemble actual business operations.
      - Create alphabetical menu lists or place the selections used frequently at the top of the menu list.
      - Provide shortcuts so experienced users can avoid multiple menu levels.
      - Use a duplicate value function that enables users to insert the value from the same field in the previous record.
    - - Ensure that help is always available. Help screens should provide information about menu choices, procedures, shortcuts, and errors.
      - Provide user-selected help and context-sensitive help.
      - Require user confirmation before data deletion (Are you sure?) and provide a method of recovering data that is deleted inadvertently.
      - Provide an Undo key or a menu choice that allows the user to eradicate the results of the most recent command or action.
    - - Create input masks, which are templates or patterns that make it easier for users to enter data.
      - Also use data validation rules, which limit the acceptable values that users can enter.
      - Build in rules that enforce data integrity. For example, if the user tries to enter an order for a new customer, the customer must be added before the system will accept the order data.
    - - Display messages at a logical place on the screen, and be consistent.
      - Alert users to lengthy processing times or delays. Give users an on-screen progress report, especially if the delay is lengthy.
      - Allow messages to remain on the screen long enough for users to read them. In some cases, the screen should display messages until the user takes some action.
    - - Use appropriate colors to highlight different areas of the screen; avoid gaudy and bright colors.
      - Use hyperlinks that allow users to jump to related topics.
      - Group related objects and information. Visualize the screen the way a user will see it, and simulate the tasks that the user will perform.
    - - Provide a keystroke alternative for each menu command, with easy-to-remember letters, such as File, Exit, and Help.
      - Use familiar commands if possible, such as Cut, Copy, and Paste.
      - Provide a Windows look and feel in your interface design if users are familiar with Windows-based applications.
- - - - Input Design
        
        -The goal of input design is to capture accurate information for the system simply and easily.
        
        Objectives Of Input Design -
        
        Controlling amount of input
        
        Avoiding delay
        
        Avoiding errors in data
        
        Keeping the process simple
        
        To produce a cost-effectiveness method of input
        
        To achieve a high-level of accuracy
        
        To ensure that the input is acceptable to users.
        
        Data Entry Screen Design Guideline
        
        -Display a sample format if a user must enter values in a field in a specific format.
        
        Use a default value when a field value will be constant for successive records or
        
        Data Capture vs Data Entry
        
        -Data entry is the process of manually entering data into the information system, usually in the form of keystrokes, mouse clicks, touch screens, or spoken words.
        
        Input and Data Entry Method
        -Input methods should be cost-efficient, timely, and as simple as possible.
        -Systems analysts study transactions and business operations to determine how and when data should enter the system.
        
        Batch Input
        
        -Using batch input, data entry usually is performed on a specified time schedule, such as daily, weekly, monthly, or longer.
        
        For example, batch input occurs when a payroll department collects time cards at the end of the week and enters the data as a batch.
        
        Online Input
        
        Businesses that use point-of-sale (POS) terminals equipped with bar code scanners and magnetic swipe scanners to input credit card data.
        
        Automatic teller machines (ATMs) that read data strips on bank cards.
        
        Factory employees who use magnetic ID cards to clock on and off specific jobs so the company can track production costs accurately.
        
        Validation Rules
        
        -A sequence check is used when the data must be in some predetermined sequence.
        
        If the user must enter work orders in numerical sequence, for example, then an out-of-sequence order number indicates an error,
        -A combination check is performed on two or more fields to ensure that they are consistent or reasonable when considered together.
        -For example, if an order input for 30 units of a particular item has an input discount rate applicable only for purchases of 100 or more units, then the combination is invalid; either the input order quantity or the input discount rate is incorrect.
- - - - An existence check is used for mandatory data items.
        For example, if an employee record requires a Social Security number, an existence check would not allow the user to save the record until he or she enters a suitable value in the Social Security number field.
        
        A data type check tests to ensure that a data item fits the required data type.
        For example, a numeric field must have only numbers or numeric symbols, and an alphabetic field can contain only the characters A through Z (or a through z).
        
        A range check tests data items to verify that they fall between a specified minimum and maximum value.
        The daily hours worked by an employee, for example, must fall within the range of 0 to 24. When the validation check involves a minimum or a maximum value, but not both, it is called a limit check.
        Checking that a payment amount is greater than zero, but not specifying a maximum value, is an example of a limit check.
        
        A reasonableness check identifies values that are questionable, but not necessarily wrong.
        For example, input payment values of $.05 and $5,000,000.00 both pass a simple limit check for a payment value greater than zero, and yet both values could be errors.
        Similarly, a daily hours worked value of 24 passes a 0 to 24 range check; however, the value seems unusual, and the system should verify it using a reasonableness check.
        
        A validity check is used for data items that must have certain values. For example, if an inventory system has 20 valid item classes, then any input item that does not match one of the valid classes will fail the check.
        Verifying that a customer number on an order matches a customer number in the customer file is another type of validity check.
        Because the value entered must refer to another value, that type of check also is called referential integrity.
        Another validity check might verify that a new customer number does not match a number already stored in the customer master file.
        
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  - - - Overview of Report Design
        Few firms have been able to eliminate printed output totally
        Turnaround documents
        Reports must be easy to read and well organized
        Database programs include a variety of report design tools
        Character-based reports – fast and inexpensive in large scale
    - - Detail reports
        Exception reports
        Summary reports
        
        Detail reports
        Produces one or more lines of output for each record processed. Each line of output printed is called a detail line.
        
        Exception reports
        Displays only those records that meet a specific condition or conditions. It is useful when the user wants information only on records that might require action, but does not need to know the details.
        
        Summary reports
        Displays the summary, e.g. Upper-level managers often want to see total figures and do not need supporting details.
    - - Printed reports are an important way of delivering information, so users should approve all report designs in advance
        Submit each design for approval as you complete it, rather than waiting until you finish all report designs
        Mock-up / prototype – sample report
        Report analysis form
  - - - The report footer, which appears at the end of the report, can include grand totals for numeric fields and other end-of-report information.
        
        A page header, which appears at the top of the page and includes the column headings that identify the data. The headings should be short but descriptive. Avoid abbreviations unless you know that users will understand them clearly.
        
        Either a page header or a page footer, which appears at the bottom of the page, is used to display the report title and the page number.
  - - - Output security protects privacy rights and shields the organization’s proprietary data from theft or unauthorized access. To ensure output security, you must perform several
        
        limit the number of printed copies and use a tracking procedure to account for each copy.
        When printed output is distributed from a central location, you should use specific procedures to ensure that the output is delivered to authorized recipients only.
        That is especially true when reports contain sensitive information, such as payroll data. All sensitive reports should be stored in secure areas. All pages of confidential reports should be labelled appropriately.