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CHAPTER 4 : SYSTEM DESIGN - Coggle Diagram
CHAPTER 4 : SYSTEM DESIGN
4.1 UNDERSTAND USER INTERFACE DESIGN (UI)
USER INTERFACE DESIGN
how users interact with a computer system,
and consists of all the hardware, software, screens, menus, functions, output,
1) Evolution of the User Interface
user interface mainly consisted of process-control screens that allowed the user to send commands to the system.
i. User-centered system
Requires an understanding of human-computer interaction and user-centered design principles
2) Human-Computer Interaction
human-computer interaction is the relationship between computers and people who use them to perform their jobs
human-computer interface started in the 1980s with users typing complex commands in green text on a black screen.
Main objective is to create a user-friendly design that is easy to learn and use
the interface will be based on the perspective of a user rather than a computer engineer, programmer, or systems analyst.
User rights suggested by IBM’s Dr. Clare-Marie Karat.
10 user rights :
perspective
installation
compliance
instruction
control
feedback
dependencies
scope
assistance
usability
7 Principles of user-centered design :
Understand the Business
Maximize Graphical Effectiveness
Think Like a User
Use Models and Prototypes
Focus on Usability
Invite FeedbackInvite Feedback
Document Everything
USER INTERFACE DESIGN GUIDELINES
Good user interface design is based on a combination of:
1) Ergonomics - how people work, learn & interact with computers
2) Aesthetics - how an interface can be made attractive & easy to use .
3) Interface technology - operational structured required to carry out the design objectives
8 basic guidelines :
1) Design a transparent interface
2) Create an interface that is easy to learn and use
3) Enhance user productivity
4) Make it easy for users to obtain help or correct errors
5) Minimize input data problems
6) Provide feedback to users
7) Create an attractive layout and design
8) Use familiar terms and images
12 Screen Elements & Controls
Menu bar
Toolbar
Command button
Dialog box
Text box
Toggle button
List box – scroll bar
Drop-down list box
Option button, or radio button
Check box
Calendar control
Switchboard
SOURCE DOCUMENTS
collects input data
triggers or authorizes an input action
provides a record of the original transaction
paper-based, but also can be provided online
developed during input design stage
The placement of information on a form also is important.
4.2 INPUT & OUTPUT DESIGN
Input Design & Technology Issues
quality of the output = quality of the input
garbage in, garbage out (GIGO) -the best time to avoid problems is when the data is entered
Guidelines For Data Entry Screen Design
Data Entry Screens
15 guidelines :
1) Restrict user access to screen locations where data is entered
2) Provide a descriptive caption for every field, and show the user where to enter the data and the required or maximum field size
3) Display a sample format if a user must enter values in a field in a specific format - separator
4) Require an ending keystroke for every field
5) Do not require users to type leading zeroes for numeric fields
6) Do not require users to type trailing zeroes for numbers that include decimals
7) Display default values so operators can press the ENTER key to accept the suggested value
8) Use a default value when a field value will be constant for successive records or throughout the data entry session
9) Display a list of acceptable values for fields, and provide meaningful error messages
10) Provide a way to leave the data entry screen at any time without entering the current record
11) Provide users with an opportunity to confirm the accuracy of input data before entering it
12) Provide a means for users to move among fields on the form
13) Design the screen form layout to match the layout of the source document
14) Allow users to add, change, delete, and view records
15) Provide a method to allow users to search for specific information
Objectives of Input Design
to ensure the quality, accuracy, and timeliness of input data
Good input design requires attention to human factors as well as technology issues
Data Capture vs Data Entry
Data capture
service in which data is captured via tick or check boxes and other items where areas are filled in with simple lines or shapes in order to get the right answer.
usually multiple choice answers / yes or no questions
Data entry
manually entered text, copying exactly what the person who filled out the feedback form has written.
not possible for computers to completely automate handwriting and this can be a somewhat more costly procedure
Input & Data Entry Method
A) Batch Input
data entry is performed on a specified time schedule [ daily, weekly, monthly, or longer ]
B) Online Input
batch input - used in specific situations
most business activity requires online data entry
Advantages:
immediate validation
availability of data
popular online input method = source data automation
Source data automation is fast and accurate, and minimizes human involvement in the translation process.
Input Mask & Validation Rules
Validation Rules
8 types of data validation rules:
1) Sequence check
2) Existence check
3) Data type check
4) Range check
5) Reasonableness check
6) Validity check
7) Combination check
8) Batch controls
Output Technology
A) Internet based information delivery
1) Blogs
Web-based logs, called blogs, are another form of Web-based output.
Blogs are useful for posting news, reviewing current events, and promoting products.
2) Instant messaging
This popular form of communication is another way for individuals and companies to communicate effectively over the Internet.
B) Printed reports
C) Specialized forms of output
An incredibly diverse marketplace requires many forms of specialized output and devices
Types Of Reports
Detail reports
Exception reports
Summary reports
8 Design Report Principles
Report headers and footers
Page headers and footers
Column heading alignment
Column spacing
Field order
Grouping detail lines
Repeating fields
Consistent design
Input & Output Controls & Security
Output control & security
Output security protects privacy rights and shields the organization’s proprietary data from theft or unauthorized access.
The IT department is responsible for output control and security measures
Input control & security
Input control includes the necessary measures to ensure that input data is correct, complete, and secure.
When a batch input method is used, the computer can produce an input log file that identifies and documents the data entered.
Data security policies and procedures protect data from loss or damage, which is a vital goal in every organization.