chp5 interface design
TRANSCRIPT
CHAPTER CHAPTER 55OUTPUT AND OUTPUT AND
USER USER INTERFACE INTERFACE
DESIGNDESIGN
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PHASE DESCRIPTION Systems Design is the third of five phases in
the systems development life cycle (SDLC) Now you are ready to begin the physical
design of the system that will meet the specifications described in the system requirements document
Systems design tasks include output and user interface design, data design, and system architecture
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CHAPTER OBJECTIVES Discuss output design issues and various
types of output Design various types of reports, and suggest
output controls and security Explain the concept of user interface design
and human-computer interaction, including the basic principles of user-centered design
List specific guidelines for user interface design
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CHAPTER OBJECTIVES Describe user interface techniques, including
screen elements and controls Explain input design concepts, techniques,
and methods Describe guidelines for data entry screen
design Use validation checks for reducing input
errors Design effective source documents and input
controls
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INTRODUCTION Output and user interface design is the first task
in the systems design phase of the SDLC Output design focuses on user needs for screen
and printed forms of output, while user interface design stresses user interaction with the computer, including input design and procedures
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OUTPUT DESIGN Before designing output, ask yourself several questions:
What is the purpose of the output? Who wants the information, why it is it needed, and how
will it be used? What specific information will be included? Will the output be printed, viewed on-screen, or both?
What type of device will the output go to? To complete your understanding, you should meet with the
users to find out exactly what kind of output is needed Your answers will affect your output design strategies
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TYPES OF OUTPUT Although most output are screen display and printed
matter, technology is having enormous impact on how people commun and obtain information
Output can take many forms Here are various output types & technology available
Internet-based information delivery E-mail Audio – audio output Automated facsimile systems
Faxback systems Computer output microfilm (COM)
Microfilm, microfiche Computer output to laser disk (COLD)
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SPECIALIZED FORMS OF OUTPUT An incredibly diverse marketplace requires a variety
of specialized output Output from one system often becomes input into
another system Eg production data from manufacturing system becomes
input to the inventory system Although digital technology has opened new
horizons in business communications, printed output still is a common type of output, and specific considerations apply to it
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PRINTED AND SCREEN OUTPUT Although many organizations strive to reduce the
flow of paper and printed reports, few firms have been able to eliminate printed output totally
Because they are portable, printed reports are convenient, and even necessary in some situations
Printed output also is used as Turnaround documents, which are output document that are later entered back into the same or another IS Eg telephone bill might be turnaround document printed
by the company’s billing system. When you return the required portion of the bill with your check, the bill is scanned into the company’s account receivable system to record the payment
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REPORTS Whether printed or viewed-on screen, report should be
attractive and easy to understand To be useful, report must include info that user need
Detail reports Produce one or more lines of output for each record processes Detail line Control field Control break Control break report Can be quite lengthy Better alternative is to produce an exception report
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REPORTS Exception reports
Display only those record that meet a specific condition
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REPORTS Summary reports
Report used by individuals at higher levels in the organization include less details than reports used by lower level employees
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USER INVOLVEMENT IN REPORT DESIGN
Printed reports are an important way of delivering information to users, so recipients should approve all report designs in advance
To avoid problems submit each design for approval as you complete it, rather than waiting until you finish all report designs
When design a report, prepare a sample report called Mock-up or prototype for user to review
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REPORT DESIGN PRINCIPLES Printed reports must be attractive, professional,
and easy to read Report headers and footers Page headers and footers Column heading alignment Column spacing
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REPORT DESIGN PRINCIPLES Field order
Fields should be displayed and grouped in a logical order
Grouping detail lines It is meaningful to arrange detail lines in groups Group header Group footer
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REPORT DESIGN ISSUES Too much detail is on the page, forcing users to
search for the information they need Good design standards produce reports that are
uniform and consistent When a system produces multiple reports, each
report should share common design elements After a report design is approved, you should
document the design in a report analysis form
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DESIGNING CHARACTER-BASED REPORTS Although majority report designed in graphical
environment, many system still produce one or more character-based reports
That use a character set with fixed spacing When report designer create or modify a
character-based report, they use a traditional tool that still work, called printer spacing chart
It is a grid of rows and column where u indicate print position and field sizes
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OUTPUT CONTROL AND SECURITY Output must be accurate, complete, current, and
secure Company uses various output control method to
maintain integrity and security Output security – protect privacy rights and shield
organization’s property data from theft or unauthorize acc
The IT department is responsible for output control and security measures
Many companies have installed diskless workstations
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A diskless workstation support a full-featured user interface,But can limit the printing or copying of data
USER INTERFACE DESIGN
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USER INTERFACE DESIGN Although output design involves a separate set of
physical design issues, it is an integral part of a larger concept called a user interface (UI)
A UI describe how users interact with a computer system and consists of all the hardware, software, screens, menus, functions, and features that affect two-way communications between the user and the computer
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EVOLUTION OF THE USER INTERFACE Often, UI mainly consist of Process-control
screen that allow user to send command to system
As information management evolved from centralized data processing to dynamic, enterprise-wide systems, the primary focus also shifted — from the IT department to the users themselves
In a User-centered system, the distinction blurs between input, output and interface itself
UI requires an understanding of human-computer interaction and user-centered design principles
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HUMAN-COMPUTER INTERACTION A UI is based on basic principles of Human-
computer interaction (HCI) HCI describe the relationship between computers
and people who use them to perform business related tasks
Industry leaders Microsoft and IBM both devote considerable resources to user interface research
As system analyst, you’ll design UI to create a user-friendly design that is easy to learn and use
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HUMAN-COMPUTER INTERACTION History and evolution of HCI begin with user typing
complex command, through the introduction of the Graphical user interface (GUI)
Dr. Clare-Marie Karat states that “in this new computer age, the customer is not only right, the customer has rights.”
The user rights cited by Dr. Karat include Perspective – user is always right Installation – user has right to install and uninstall sw
and hw Compliance – user has right to system that perform
exactly as promised Instruction – user has right to easy –to-use instruction Control – user has right to control system and get
respond
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HUMAN-COMPUTER INTERACTION The user rights cited by Dr. Karat include
Feedback – user has right to system to provide clear, accurate info
Dependencies Scope Assistance Usability – user should be master of sw and hw
tech not vice versa
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BASIC PRINCIPLES OF USER-CENTERED DESIGN Although IT profess have different views about
interface design, most agree that good design depends on 8 basic principle:- Understand the underlying business functions Maximize graphical effectiveness Profile the system’s users Think like a user Use prototyping
StoryboardUsability metrics
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BASIC PRINCIPLES OF USER-CENTERED DESIGN Basic Principles of User-
Centered Design Design a comprehensive
interface Continue the feedback process Document the interface design
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GUIDELINES FOR USER INTERFACE DESIGN
It is important to design a UI that is easy to use, attractive and efficient
Follow eight basic guidelines1. Focus on basic objectives2. Build an interface that is easy to learn and
use3. Provide features that promote efficiency4. Make it easy for users to obtain help or
correct errors5. Minimize input data problems
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GUIDELINES FOR USER INTERFACE DESIGN
Follow eight basic guidelines6. Provide feedback to users7. Create an attractive layout and design8. Use familiar terms and images
Good user interface design is based on a combination of ergonomics, aesthetics, and interface technology
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USER INTERFACE CONTROLS The designer can include many control features
such as Menu bar Toolbar Command button Dialog box Text box Toggle button
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USER INTERFACE CONTROLS User Interface Controls
List box – scroll bar Drop-down list box Option button, or radio button Check box Calendar control Switchboard
INPUT DESIGN
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INPUT DESIGN Input technology has changed dramatically in recent
years No matter how data enters an IS, the quality of the
output is only as good as the quality of the input The concept known as Garbage in, garbage out (GIGO) During input design, determine how data will be
captured and entered into system Data capture – uses automated or manually operated
devices to identify source data and convert to compute readable form eg bar code readers
Data entry – is the process of manually entering data into IS, in a form of keystrokes or mouse clicks
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INPUT AND DATA ENTRY METHODS Input process should be efficient, timely and logical First decision is whether to use batch or online input
methods Each method has adv and disadvtg
Batch input Data entry performed on a specified time schedule eg
daily, weekly, or longer Eg payroll dept collect time cards and enter data as
batch Online input
Online data entry – use on business activity Source data automation – combine online data entry
and automated data capture using input devices eg RFID tags or magnetic data strips. Eg use at POS, ATMs
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Tradeoffs Even online input offers many advtg, it does have
some disadvtg Eg unless source data automation is used,
manual data entry is slower and more expensive than batch input because it is performed at the time the transaction occurs and often done when computer demand is at its highest
The decision to use batch or online input depends on business requirements
Eg hotel reservation must be entered and process immediately, but hotel can enter their monthly performance figures in batch. In fact some input occurs in batches
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INPUT VOLUME To reduce input volume, you must reduce
number of data items required for each transaction
Guidelines will help reduce input volume1. Input necessary data only2. Do not input data that the user can
retrieve from system files or calculate from other data
3. Do not input constant data4. Use codes
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DESIGNING DATA ENTRY SCREENS Some user work with many features of UI and
some spend time entering data Here discussed interface guideline and concept
that primarily relate to repetitive data entry Most effective method of online data entry is
form filling Guidelines will help you design data entry screens
1. Restrict user access to screen locations where data is entered
2. Provide a descriptive caption for ever field, and show the user where to enter the data and the required or maximum field size
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DESIGNING DATA ENTRY SCREENS Guidelines will help you design data entry
screens3. Display a sample format if a user must
enter values in a field in a specific format4. Require an ending keystroke for every field5. Do not require users to type leading
zeroes for numeric fields6. Do not require users to type trailing zeroes
for numbers that include decimals
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DESIGNING DATA ENTRY SCREENS Guidelines will help you design data entry screens
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
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DESIGNING DATA ENTRY SCREENS Guidelines will help you design data entry
screens10. 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
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DESIGNING DATA ENTRY SCREENS Guidelines will help you design data entry
screens13. Design the screen form layout to match
the layout of the source document14. Allow users to add, change, delete, and
view records15. Provide a method to allow users to search
for specific information
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INPUT ERRORS Reducing the number of input errors improves
data quality So, identify and correct errors before they enter
the system by using data validation check A data validation check improves input quality
by testing the data and rejecting any entry that fails to meet specified conditions
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INPUT ERRORS You can design at least eight types of data
validation checks into the input process1. Sequence check2. Existence check3. Data type check4. Range check – limit check5. Reasonableness check6. Validity check – referential integrity7. Combination check8. Batch controls – hash totals
Read detail pg 317
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INPUT CONTROL Input control include necessary measures
to ensure that input data is correct, complete and secure
Focus on input control during every phase of input design
Every piece of information should be traceable back to the input data that produced it
Provide an audit trail – that record the source of each data item and when it entered the system
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INPUT CONTROL Data security – protect data from loss or
damage Company must have a Records retention
policy that meets all legal req and business needs
Sensitive data must be encrypted in a process called encryption , so only users with decoding sw can read it
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CHAPTER SUMMARY The chapter began with a discussion of output
design issues and a description of various types of output
User-centered design principles require an analyst to understand the business functions, maximize graphical effectiveness, profile the system’s users, think like a user, use prototyping, design a comprehensive interface, continue the feedback process, and document the interface design
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CHAPTER SUMMARY An effective way to reduce input errors is to
reduce input volume You can also reduce errors by using well-
designed data entry screens and by using data validation checks
Chapter 5 Complete