This presentation covers designing and implementing the user interface, usability analysis and evaluation, introducing human and professional issues, person-related factors, and task- and environment-related factors.

1. Arab Open University
2nd
Semester, 2006-2007
M301
Unit 5.5
Human Factors and Professional
Issues
reem.attas@arabou.org.sa

2. Reem AlAttas © 2
Topic Road Map
 Designing and implementing the user
interface
Usability analysis and evaluation
Introducing human and professional
issues
Person-related factors
Task- and environment-related factors

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What is HCI?
 Human Computer Interaction.
 HCI is the study of interaction between people (users)
and computers.
 It is an interdisciplinary subject, relating computer
science with many other fields of study and research.
 Interaction between users and computers occurs at the
user interface, which includes both hardware (i.e.
peripherals and other hardware) and software (for
example determining which, and how, information is
presented to the user on a screen).

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The disciplines that contribute to HCI

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Major Contributors
1. Computing
2. Cognitive psychology: is primarily concerned with
understanding human behavior and the mental
processes that underlie it.
3. Social and organizational psychology: is concerned
with studying the nature and causes of human behavior
in a social context.
4. Ergonomics and human factors: are concerned with
maximizing the user’s safety, efficiency and reliability of
performance, and with increasing the user’s feelings of
comfort and satisfaction.

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Minor Contributors
1. Artificial intelligence.
2. Linguistics.
3. Philosophy.
4. Sociology.
5. Anthropology.
6. Design.
7. Engineering.

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What are the capabilities of humans?
Perception and representation.
Attention and memory.
Knowledge and learning.

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Perception and representation
 The main area of HCI where work on perception
and representation comes into play is in
presenting information graphically at a user
interface.
 The main techniques used are:
 Three-dimensional representations.
 Graphical coding.
 Color coding.
 Icons.

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Attention and memory
 How to guide the user’s attention to important
parts of a display?
 Presenting neither too much information nor too little on
screen.
 Spatial and temporal cues may also be used, such as
consistently putting important information in the same
place or sequencing the display of information in a
predictable way.
 Color can also guide attention.

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… Attention and memory
 Kinds of memory storage:
 Sensory store, where each of the senses holds stimuli they
receive for a few tenths of a second;
 Short-term or working memory, which holds a limited amount
of information for about 15–30 seconds;
 Long-term memory, which holds information indefinitely.
 A factor that influences how easily new material can be
stored in long-term memory is meaningfulness.
 Familiarity and imagery influence meaningfulness.

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… Attention and memory
 Factors that influence the meaningfulness of
icons include:
 The context in which the icon is being used,
 The task for which it is being used, and
 The form of representation:
 Resemblance.
 Exemplar.
 Symbolic.
 Arbitrary.

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Knowledge and learning
 One of the most important concepts in examining how a
user understands a system is that of a mental model.
 A mental model is an explanation in someone's thought
process for how something works in the real world. It is a
kind of internal symbol or representation of external
reality, hypothesized to play a major part in cognition.
 Two basic types of mental model:
 Structural model describes how a system is built.
 Functional model describes how it works.

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… Knowledge and learning
 Understanding a user’s mental model allows a
designer to construct an interface that matches it
most closely and hence reduces errors.
 Errors categories:
 Mistakes, which are conscious decisions to take
actions which turn out to be incorrect; and
 Slips, which are unintentional errors such as
accidentally pressing the wrong key or selecting the
wrong menu item by overshooting.

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Input devices
Keyboards.
Joysticks.
Mice.
Trackballs.
Speech recognition.

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Output devices
LCD's.
3D virtual reality devices.

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Communication style
Command-line interface (CLI).
Menus:
 pull-down menus.
 pop-up menus.
Fill-in forms.
Natural-language dialogue.
Direct manipulation.

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Why some interfaces cause problems
to their users?
Gulf of execution:
 user’s formulation of actions
≠ actions allowed by the system
Gulf of evaluation:
 user’s expectation of changed system state
≠ actual presentation of this state

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Widgets
 Are user-interface components.
 Standard widget names for window control:
 title bar, close box, maximize box, minimize box, scroll
bar, resize button, resize button.
 Widgets concerned with control within an
application
 inclusive check box, exclusive check box or radio
button, slider or scroll bar, button, menu, submenu, text
box, dialogue box.

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Topic Road Map
Designing and implementing the user
interface
 Usability analysis and evaluation
Introducing human and professional
issues
Person-related factors
Task- and environment-related factors

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Observation and monitoring
Direct observation: one simply watches
the users using the interface and notes
where they seem to have problems and
the sequences they follow to perform
actions.
Indirect observation: by means of a one-
way mirror or video recording.

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Collecting users’ opinions
Interviews.
Questionnaires.

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Interviews
Two main kinds of interviews:
 Structured interviews have a predetermined
set of questions and permit a relatively formal
and balanced result.
 Flexible interviews are generally based on
some predetermined set of topics, but allow the
interviewer and interviewee to explore opinions
and ideas that the interviewer may not have
considered at the outset.

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Questionnaires
Two types of question structure:
 Open questions are of the short-answer/essay
type.
 Closed questions are easier to analyze and
generate statistics from, and can take the form
of multiple-choice answers or of asking the user
to rate something on a multipoint scale.

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Usability
 The attribute that determines the effort required to learn,
operate, prepare input for, and interpret the output of a
system.
 This can be decomposed into four aspects:
 Learn ability — the time and effort to reach some particular
level of proficiency;
 Throughput — the speed at which experienced users can do
things;
 Flexibility — the extent to which changes can be
accommodated;
 Attitude to the tasks being carried out, measured by
questionnaires and interviews.

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Predictive evaluation
 Uses modeling to predict user behavior and
interface performance but does not involve any
user testing.
 Keystroke-level model: a predictive evaluation
technique that takes no account of novice
learning behavior, but instead relies on well-
established metrics which measure a known
time to complete a simple task.

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Keystroke-level model
 It models a task in
terms of the time
taken on four physical
activities, the
response time of the
system and the
mental operation time
of the user:

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Example

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Topic Road Map
Designing and implementing the user
interface
Usability analysis and evaluation
 Introducing human and professional
issues
Person-related factors
Task- and environment-related factors

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Human factors
Discipline that tries to enhance the
relationship between people and
technology, where the word ‘enhance’
means making the relationship safer or
more productive.

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Process-related human factors
1. Person-related human factors
1. The engineer’s experience of programming;
2. The engineer’s understanding of the specification.
2. Task-related human factors
3. The number of other tasks the engineer has to do;
4. The similarity between this code module and others the engineer has
implemented.
3. Environment-related human factor
5. The usability of the debugging tools;
6. The length of time the engineer can expect to work without interruption;
7. The layout and clutter of the engineer’s desk;
8. The noise in the office.

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What does it mean to be
‘professional‘?
 Profession: a form of employment, especially one that is
possible only for an educated person and after training
(such as law, medicine or teaching) and that is respected
in society as honorable.
 If you consult a professional, you expect any advice
given to be accurate and appropriate, any work resulting
from the consultation to be carried out in a competent
way, and the professional to take responsibility for the
advice given.

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Three cornerstones of professionalism
Being knowledgeable about the field.
Being competent to practice (i.E. Being
able to apply knowledge of the domain in
making technical and ethical decisions).
Taking responsibility for one’s actions.

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What does it mean to be a ‘software
professional’?
Being a member of a professional body.
Being clear in the use of language.
Being honest.

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Topic Road Map
Designing and implementing the user
interface
Usability analysis and evaluation
Introducing human and professional
issues
 Person-related factors
Task- and environment-related factors

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Individual factors
Competence in a software engineer is a
mixture of knowledge and experience with
respect to a particular task or activity, and
the ability to apply that knowledge and
experience to the task.
Motivation is what arouses the individual
to action and directs the nature of the
action over time.

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Social factors
The individual engineer must be able to:
 Work as part of a team.
 Communicate effectively with others.

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Topic Road Map
Designing and implementing the user
interface
Usability analysis and evaluation
Introducing human and professional
issues
Person-related factors
 Task- and environment-related factors

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Task-related factors
 Task complexity: Very complex tasks take a
long time to complete and are likely to involve
errors.
 Task familiarity: The more familiar the task, the
faster and less error-prone the performance of
that task will be.
 Task variability: For tasks that are highly
repetitive, automation is likely to yield benefits.

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Environment-related factors
 Physical workspace
 Privacy: Many software engineers work in open-plan offices.
 Outside awareness: well-designed, open plan environment,
which also caters for the needs of privacy.
 Personalization: the ability to arrange the workspace to suit
individual work practices and preferences.
 Methods and tools
 Ease of learning.
 Ease of use.
 Availability of training and support.

40. TMA5 – Q5

41. Thank You!