Program Development

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CS413
Design Object-oriented (OO) graphical user
interface (GUI) design model object oriented
framework concise description of complex
information items specification of complex
navigation patterns interface transformations OO
methods low-tech materials Hi-tech software
not required hi-tech Software Large
applications Critical applications
(aerospace) iterative usability
testing internal module testing testing
between models testing of system as a
whole Design a GUI conform to multiple GUI
platform stylescommon look and feel for visitor
conformabilityease of maintenanceease of
enhancements
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Designer 1. turn user data into a task flow 2.
taskflow into a GUI design 2a. mapping taskflow
into abstract task objects 2b. mapping the task
objects into GUI objects (such as windows) 3.
fill in the GUI's foundation (such as the
menus)
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2a. Task objects(high level)
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"A well-designed application is important because
business owners understand that how a website
functions will either create repeat customers or
discourage customers from visiting the site. It
is essential that a website is easy to navigate
and that it functions in an efficient manner. It
is also important for a business to be able to
correct problems with the system quickly, which
will prevent the loss of customers and profits.
As a result of the demands that are placed on
business to have an efficient website a precise
software production process is needed. (Abrahão,
Fons, Pastor 2000, 2) "
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SUMMARY well-designed application depends
upon how a website functions GOALS create
repeat customers do not discourage customers
from visiting easy to navigate functions in an
efficient manner correct problems
quickly prevent the loss of customers and
profits For an efficient website a precise
software production process is needed.
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CS413
Terminology Data Design expressing and
referencing data elements, classes, and
categories Data Elements and Data Classes data
element a single data entity (such  as a last
name or phone number) correspond to a specific
piece of information represent streams of
data (such as a user's click stream) data
class a named set of data elements and/or other
data classes inherit the data elements from all
classes they contain base set well known data
classes neither user nor service can change a
base data class allows for a common
understanding between user agent and
service simplify the negotiation process between
user and designer
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CS413
result set a set of data elements sent by a user
agent to the service as a result of a
request Result sets contain traditional value
pairs wherein one half of the pair describes the
value and the other is the value
itself http//www.pifergolf.com/ contact
page ltform method"post action"contactformasp.as
p"gt ltinput name"emailaddress" type"text"
size25gt Result set emailaddress.morris.fulcher_at_
baker.edu lttextarea name"textdata" rows6
cols45 wrapgtlt/textareagt Result set
textdata.what ever the visitor typed ltinput
type"checkbox" name"newgolfcart"
value"yes"gt Result set newgolfcart.yes or
newgolfcart.no ltinput type"submit"
value"Submit"gt ltinput type"reset"
value"Clear/Reset"gt lt/formgt
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Data Categories data category a quality of a
data element or class a hint to the
designer regarding the type of an unrecognized
data element regarding the sensitivity of an
unrecognized data element describe the
characteristics of a data element set/identify
user preferences Example a data element
shoe_size. Demographic data. User preferences,
relative to the data element, can be identified,
monitored and tracked.
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A scenario is a partial description of the
application behavior that occurs at a given
moment Desired properties of object orientated
design extensibility reusability understandabil
ity robustness portability efficiency
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World Wide Web Consortium (W3C) lead the World
Wide Web to its full potential by developing
common protocols that promote its evolution and
ensure its interoperability .Object Oriented
Hypermedia Design Model.
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• Graphical User Interface
• Ensure usability in Human-computer Interaction
• User Interface
• Thousands of colorsThree-dimensional (3-D)
  graphicsIconsButtonsInput areas (text,
  numeric)Animation
• The first thing people discuss
• To users, the interface is the system
• Communication wit the system is at least as
  important as the computations and manipulations
  of the system
• Current system problems (or are they?)
• The system is down (banks)User misses a screen
  (airline tickets)Computer wont let me . .
  (restaurant separate checks)The computer is
  wrong . . . (incorrect information)Its already
  in the computer, Ill never get it figured out
• What is the problem?

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Graphical User Interface Goals To the user
usability has become a key issue Developer
Perspective Ensuring usability has become
(finally) an important issueOver 48 of code is
to support the user interface Historical
PerspectiveThe user interface is not an integral
part of the systemThe user interface is just a
box to and from a userThe important areas are
the system functions (code) Reality The user
interface development is an integral part of the
overall software engineering process Cost
Factors Companies are more aware of interface
issuesThe interface usability can be
costly Software purchase Hardware
purchase Employee time Learning
curve Frustration curve Productivity
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Cost Factors Companies are more aware of
interface issuesThe interface usability can be
costly Software purchase Hardware
purchase Employee time Learning
curve Frustration curve Productivity Fighti
ng with the system Recovering from
errors Initial cost of the system is a one time
event Employee expenses are daily
occurrences Applications InternetBusiness
(airlines to restaurants)SpreadsheetsWord
ProcessorsRealistic computer games
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• What is Usability?
• User friendly?
• Hassle-free productivity?
• User-oriented characteristics for usability
• Ease of learning (learning curve)
• High speed of user task performance
• Low user error rate
• Subjective user satisfaction
• User retention over time (learning curve)
• Usability is
• The users effectiveness with the interface
• The users efficiency with the interface
• The users reaction to the interface

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Human Design Issues Programmers
viewpoint Widgets Interactions (programs,
modules, etc.) Calls to modules Everything to
build a user interface (techie stuff) FACT
anyone can design a user interface! This cant
be hard its just common sense Designers and
Managers Do not believe there is a
problem Product planners and marketing Low
importance issue Provides sales sizzle
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Mistakes as Positive Signs The system has to be
good, it sells so well.The marketplace is
showing a great deal of interestIt may be the
only product of its kindIt may be prolific in
the marketplace (Microsoft) We arent hearing
any complaints about the interface Some users
simply wont complainUsers may think the problem
is their usage abilities Cost Benefit
Analysis The purchaser may not be the userA
large gap between purchaser and
user Insufficient information to the purchaser
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• Characteristics of why interfaces fail
• Designed by software people, not human-computer
  interactions specialists
• Developed by strict top-down, functional
  decomposition
• Not developed to meet written, measurable
  usability specifications
• Not prototyped while being developed
• Not developed with an iterative refinement
  process
• Not empirically evaluated

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• Human-computer interaction (HCI)
• When a human user and a computer system get
  together to perform tasks
• Interaction Component
• How a user interface works
• The interface look and feel
• Behavior in response to what a user sees and
  hears and does
• Interface Software
• The means for implementing the code

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Behavioral and Constructional Domains Behavioral
Domain Interaction Component The people who
design and develop the interaction
component Interaction is described
abstractly Behavior of the user Interactions
between user and computer Involve Human
factors, guidelines and rules, human cognitive
limitations, graphic design, interaction
styles, scenarios, usability specifications,
rapid prototyping, evaluation with human
users Constructional Domain Development
Component The people who design and develop the
interaction software Involve Widgets,
algorithms, programming, procedure libraries,
control and data flow, state transition
diagrams, event handlers, object-oriented
representations Problem The domains have
requirements that do not overlap Result
interfaces of varying quality and usability
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The merged results of both behavioral and
constructional designs determines interface
usability. Problem The domains have
requirements that do not overlap Result Interfaces
of varying quality and usability
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Comparing Behavioral and Constructional Domains
Behavioral Constructional
What is being developed Interaction component of interface Interface software
What view is adopted View of the user View of the system
What is described User actions, perceptions, and tasks System actions in response to what the user does
What is involved Human factors, scenarios, detailed representations, usability specifications, evaluation Algorithms, data structures, widgets, programming
The local Where interaction designers and evaluators do their work Where interface software implementers do their work
The test Procedures performed by the user Procedures performed by the system