Download Week #7

Systems Analysis I
Interface Design
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Glenn Booker
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Interface Objectives
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Key objectives for designing a “good”
interface include
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Match type of interface to the task
Make interface efficient
Provide appropriate feedback to users
Generate usable queries
Improve productivity of knowledge workers
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Interface Parts
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A user interface consists of two parts
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The presentation language takes computer
signals and makes them readable by humans
The action language takes human inputs and
makes them usable by the computer
Together, these parts constitute what we
call a user interface
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Types of Interfaces
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Types of interfaces include
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Natural language
Question and answer
Menus
Form-fill
Command language
Graphical user interface (GUI)
And a few other
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Natural language
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Natural language processing is the
foundation for being able to ask a database
native language (e.g. English) questions
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www.ask.com handles natural language WWW
queries, but is now full of Featured Sponsors
Practical information systems have trouble
with natural language, due to the vagueness
of human languages
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Question and Answer
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Q&A interfaces are typically used when
a limited range of activities and options
are needed
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Good for inexperienced users
Often used for help services (e.g. wizards),
and installation routines
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Menus
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Menu interfaces are familiar from almost
every Windows and Mac application
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Menus are activated based on mouse click or
keyboard commands
Allows for many command options
User is expected to know what kind of task they
want to perform
More primitive menu systems were based on
typing a command letter at each screen
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Form-fill
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Also known as form based or input/output
interfaces, this replicates paper forms to
provide a familiar environment to the user
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Forms appear to be filled out by the user
Fields needing data are backlit, colored, or
otherwise highlighted
Default values and field screens can encourage
fast and accurate data entry
Poor choice for experienced users
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Command language
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A command language interface is used by
typing commands onto a screen
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Akin to DOS- or UNIX-based command prompts
Commands must be learned, and typed correctly
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Steep learning curve
Very efficient for experienced users
Good for very complex applications, e.g.
AutoCAD, Mathematica, etc.
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Graphical user interface (GUI)
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GUIs allow direct manipulation of graphic
interface objects, providing constant
feedback for the user
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The objects must provide a conceptual model
of the environment depicted, producing a
design challenge
Users of Web-based GUIs may be completely
unknown, so expressing good icons and language
are challenging
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Other Interfaces
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Other types of interfaces exist, and are
becoming increasingly common
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Pointing devices (stylus, tablet PC, touch screen)
Voice recognition systems
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Interface Type Selection
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When choosing the type of interface, should
consider
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The number of users, and their experience level
Turnover rate – how long do users stay with the
system?
Training period should be brief
New users should have noticeable productivity
Users errors are few and easy to fix
Occasional users should relearn system quickly
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Dialog Design
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The dialog between computer and user is
critical to the success of any system
Want to have
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Meaningful communication
Minimal user action
Standard operation and consistency
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Meaningful Communication
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A system needs to present information clearly
to the user (duh!)
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Need to format data into recognizable forms
Give clear instructions
Novice users require more instructions
and feedback
Help screens or other support tools should
be provided
Validate inputs to ensure computer understands
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Minimal User Action
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Typing is often the slowest part of a system
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Key in codes instead of full words, or select from
a dropdown list where possible
Only enter new data
Format data as user would expect it
Provide default values where possible
Have system look up names or items, to avoid
typing the whole entry
Provide keyboard shortcuts
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Standard Operation
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Make the user interface consistent
throughout the application
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Put common elements in the same place on each
screen, and use consistent fonts and layout
Use the same function keys or keyboard shortcuts
everywhere
Use standard shortcuts, like F1 = Help, Esc = exit
Use consistent colors and icons everywhere
Provide consistent navigation scheme
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User Feedback
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In order for there to be a DIalog between
computer and user, the computer must
provide good and frequent feedback
Feedback generally compares the intended
result with an actual result, or tells the user
what is expected next
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Types of Feedback
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There are many types of feedback
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Acknowledge input – tell the user when an input
has been received by the system
Input is valid – tell user that the inputs are in the
correct form; it has passed validation
Input is invalid – tell user when inputs are not
valid; and specifically how to fix them
Explain delays – tell the user why there is a delay,
so they don’t assume the system crashed
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Types of Feedback
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Tell when task was completed – tell the user when
a request or process has been completed
successfully; or conversely
Tell when a task wasn’t completed – tell the user if
something didn’t complete; and tell them how to
redo it or fix the problem
Provide additional instructions – provide a way
for users to get more information on the current
process, or what they can do next
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Feedback in Design
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Use lots of help options
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Generic F1 Help
Context-sensitive help
Balloon help
Wizards
Customer support phone or email
Support forums, chat areas, user groups, etc.
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E-Commerce Notes
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In addition to providing user feedback, many
e-commerce web sites also solicit feedback
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Provide an email link for product comments, help
requests, website corrections, etc.
Many use one-click navigation
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Create using rollover menus, hierarchical links,
creating a site map, or using a common
navigation bar
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Query Types
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Query structure is outside the scope of this
class; typical uses include
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Look up a value for a given record
Find records matching a condition for an attribute
Find when a given attribute has some value
Show an entire record
Show all records which have a given attribute
List attributes that have a given value
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Query Methods
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There are two major methods for querying
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Query by Example (QBE) is done in Access
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Structured Query Language (SQL) is used in
every major database system
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Select the fields of interest, and enter query values
Is a click-and-drag way to create queries
Uses text commands to specify what tables, attributes,
and values are to be evaluated or shown
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Web Searching
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Zillions of resources are available, of varying
levels of accuracy and completeness, by
searching the WWW
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Google is a favorite starting point
Try www.firstgov.gov for searching state and/or
federal government web sites
Choose search terms carefully
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Spell out part of acronyms
Apply logical rules for searches (e.g. AND,
OR, exact)
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Data Mining
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Data mining studies past behavior (e.g. sales
history) to look for meaningful patterns
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Often used for marketing or sales, such as
targeting an ad campaign
Can create a consumer profile based on
purchase history
Lots of potential privacy issues
Data mining tends to be expensive, due to
severe computational requirements
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