PRINCIPLE OF HUMAN COMPUTER INTERACTION * INTRODUCTION TO HCI * OUTLINEIntroductionWhat is HCI?The HCI ChallengeHCI is Not aboutHCI is aboutThe goals of HCIWhat is Usability?Why is usability important?Why HCI is Important in the Context of WWW?It is not Simple to Make Good User InterfacesExamples of good and bad design * * INTRODUCTION Interacting with technology has become an essential part of everyday life for the majority of people. The average user of a computer system is now less likely to understand the technology. Since, there are different types of technology they have to use. People are busy and may spend little or no time actually learning a new system. * INTRODUCTION..(CONT.) Therefore, computer systems should be easy to use, easy to learn, and with no errors. To design and develop of such a system is a major concern of HCI * WHAT IS HCI?Human-computer interaction (HCI): “is a discipline concerned with the design, evaluation and implementation of interactive systems for human use and with study of major phenomena surrounding them.” (ACM SIGCHI, 1992, p. 6) WHAT IS HCI?HCI (human-computer interaction) is the study of interaction between people (users) and computers. Interaction between users and computers occurs at the user interface The golden principle in HCI is that “people should come first”. * WHAT ..(CONT.) HCI consists of three parts:Human: could be an individual user or a group of users.Computer: could be any technology ranging from the general desktop computer to a large scale computer system.Interaction: any direct or indirect communication between a human and computer. * WHAT ..(CONT.)HCI concentrates on the study of human factors The study of human factors started during the Second World War by US army. Usability was born because of badly designed arms that caused “friendly fire” during war. * THE HCI CHALLENGE * HCI IS NOT ABOUTMaking the interface look pretty Only about desktop computers (and that goes for computing as well!) Something that would be nice to do but usually there’s no time for it * HCI IS ABOUTUnderstanding the usersUnderstanding users tasksUnderstanding the surrounding environmentGUI requirements gathering and analysisDesign prototypeEvaluate the system * THE GOALS OF HCIThe goal of HCI “is to develop or improve the safety, utility, effectiveness, efficiency and usability of system that include computers.” (Interacting with computers, 1989, p3) * THE GOALS OF HCIThe goals of HCI are to produce usable and safe systems, as well as functional systems. In order to fulfill that, developers must attempt to: Understand how people use technology Building suitable systems Achieve efficient, effective, and safe interaction Put people first People needs, capabilities and preferences should come first. People should not have to change the way that they use a system. Instead, the system should be designed to match their requirements * WH.

1. PRINCIPLE OF HUMAN COMPUTER INTERACTION
*
INTRODUCTION TO HCI
*
OUTLINEIntroductionWhat is HCI?The HCI ChallengeHCI is
Not aboutHCI is aboutThe goals of HCIWhat is Usability?Why
is usability important?Why HCI is Important in the Context of
WWW?It is not Simple to Make Good User InterfacesExamples
of good and bad design
*
*
INTRODUCTION
Interacting with technology has become an essential part of

2. everyday life for the majority of people.
The average user of a computer system is now less likely to
understand the technology. Since, there are different types of
technology they have to use.
People are busy and may spend little or no time actually
learning a new system.
*
INTRODUCTION..(CONT.)
Therefore, computer systems should be easy to use, easy to
learn, and with no errors.
To design and develop of such a system is a major concern of
HCI
*
WHAT IS HCI?Human-computer interaction (HCI): “is a
discipline concerned with the design, evaluation and
implementation of interactive systems for human use and with
study of major phenomena surrounding them.”
(ACM SIGCHI, 1992, p. 6)

3. WHAT IS HCI?HCI (human-computer interaction) is the study
of interaction between people (users) and computers.
Interaction between users and computers occurs at the user
interface
The golden principle in HCI is that “people should come first”.
*
WHAT ..(CONT.)
HCI consists of three parts:Human: could be an individual user
or a group of users.Computer: could be any technology ranging
from the general desktop computer to a large scale computer
system.Interaction: any direct or indirect communication
between a human and computer.
*
WHAT ..(CONT.)HCI concentrates on the study of human
factors
The study of human factors started during the Second World
War by US army.
Usability was born because of badly designed arms that caused
“friendly fire” during war.
*

4. THE HCI CHALLENGE
*
HCI IS NOT ABOUTMaking the interface look pretty
Only about desktop computers (and that goes for computing as
well!)
Something that would be nice to do but usually there’s no time
for it
*
HCI IS ABOUTUnderstanding the usersUnderstanding users
tasksUnderstanding the surrounding environmentGUI
requirements gathering and analysisDesign prototypeEvaluate
the system
*
THE GOALS OF HCIThe goal of HCI “is to develop or improve
the safety, utility, effectiveness, efficiency and usability of
system that include computers.”
(Interacting with computers, 1989, p3)
*

5. THE GOALS OF HCIThe goals of HCI are to produce usable
and safe systems, as well as functional systems. In order to
fulfill that, developers must attempt to:
Understand how people use technology
Building suitable systems
Achieve efficient, effective, and safe interaction
Put people first
People needs, capabilities and preferences should come
first. People should not have to change the way that they use a
system. Instead, the system should be designed to match their
requirements
*
WHAT IS USABILITY?A usable system is:easy to useeasy to
learneasy to remember how to useeffective to useefficient to
usesafe to useenjoyable to use
*
WHY IS USABILITY IMPORTANT?
A Good user-interface can:
1. Earn a company billions.
2. Increase users loyalty.
3. Increase users trust.
4. Makes users happy : )

6. *
WHY ..(CONT.)
A Bad user-interface can:
1. be annoying, embarrassing, frustrating, and even deadly.
2. Increase mistakes in data entry and system operation.
3. Makes functions become completely inaccessible.
4. System failure because of user rejection.
*
WHY HCI IS IMPORTANT IN THE CONTEXT OF WWW?
• Competition is very close (just another link…)
• Comparison is easily possible (example – Online-Shop)
• Users who can’t find the product in the shop can not buy it
• Users who are not able to fill in correctly the order form are
not going to buy
*
IT IS NOT SIMPLE TO MAKE GOOD
USER INTERFACES
Basic misconceptions:
• If I (the developer) can use it, everyone can use it

7. • If our non-technical staff can use it, everyone can
• Good user interfaces are applied common sense
• A system is usable if all style guidelines are met
*
EXAMPLES OF GOOD AND BAD DESIGN
*
EXAMPLES ..(CONT.)
*
EXAMPLES ..(CONT.)
*
EXAMPLES ..(CONT.)
*
USABILITY REQUIREMENTSSynonyms for “user-friendly” in
Microsoft Word 2002 are: easy to use; accessible;

8. comprehensible; intelligible; idiot proof; available; and
readyThese measures are still subjective, so a systematic
process is necessary to develop usable systems for specific
users in a specific context
GOALS FOR REQUIREMENTS ANALYSISAscertain the user’s
needsDetermine what tasks and subtasks must be carried out
Include tasks which are only performed occasionally. Common
tasks are easy to identify. Functionality must match need or else
users will reject or underutilize the product
GOALS FOR REQUIREMENTS ANALYSISEnsure reliability
Actions must function as specified Database data displayed
must reflect the actual databaseThe system should be available
as often as possibleThe system must not introduce errors Ensure
the user's privacy and data security by protecting against
unwarranted access, destruction of data, and malicious
tampering
GOALS FOR REQUIREMENTS ANALYSISEnsure reliability
Actions must function as specified Database data displayed
must reflect the actual databaseThe system should be available
as often as possibleThe system must not introduce errors Ensure
the user's privacy and data security by protecting against
unwarranted access, destruction of data, and malicious
tampering
GOALS FOR REQUIREMENTS ANALYSISComplete projects

9. on time and within budget
Late or over budget products can create serious pressure within
a company and potentially mean dissatisfied customers and loss
of business to competitors
USABILITY MEASURESDefine the target user community and
class of tasks associated with the interface 5 human factors
central to community evaluation: Time to learn
How long does it take for typical members of the community to
learn relevant task? Speed of performance
How long does it take to perform relevant benchmarks? Rate of
errors by users
How many and what kinds of errors are made during benchmark
tasks? Subjective satisfaction
Allow for user feedback via interviews, free-form comments
and satisfaction scales
UNIVERSAL USABILITYPhysical abilities and physical
workplacesBasic data about human dimensions comes from
research in anthropometry There is no average user, either
compromises must be made or multiple versions of a system
must be created Physical measurement of human dimensions are
not enough
UNIVERSAL USABILITY (CONT.)Personality

10. differencesThere is no set taxonomy for identifying user
personality types Designers must be aware that populations are
subdivided and that these subdivisions have various responses
to different stimuli
UNIVERSAL USABILITY (CONT.)Gender differencesNo clear
patterns have emergedGamesTend to be aimed at young
malesHighest demographic of online players: older
womenProductivity toolsLargely male designers
UNIVERSAL USABILITY (CONT.)Users with
disabilitiesDesigners must plan early to accommodate users
with disabilities Early planning is more cost efficient than
adding on later Businesses must comply with the "Americans
With Disabilities" Act for some applications
Designing for/with childrenBroad term: toddlers to
teenagersParental control and safety vs desire of challenge and
learning
Elderly UsersIncluding the elderly is fairly ease, designers
should allow for variability within their applications via
settings for sound, color, brightness, font sizes, etc.
UNIVERSAL USABILITY (CONT.)Some practical user
typesThe BeginnerJust starting out, possibly not very
technicalWill need lots of hand-holding, at least to startEver try
teaching your grandmother AOL?The Casual UserUses the
system infrequentlyUses short-cuts, occasionally needs helpThe
“Technically Challenged” UserDoesn’t know, doesn’t want to
know!Will need lots of hand-holding (i.e., help system)

11. UNIVERSAL USABILITY (CONT.)Some more practical user
typesThe Power UserFrequent user, loves the features, pushes
all buttonsWants efficiency and customizationThe Technical
Guru“If I had written this…”Probably lots of pre-conceptions
USABILITY TOPIC: COLOR BLINDNESSAbout 8% of men
have color blindness of some type, and about 0.5% of women
Misnomer: most people see color difference of some kindColor
deficiencyMonochromacy, very rare conditionGenetic condition,
alteration of the cones in the eye
TYPES OF COLOR BLINDNESSProtanopia – L-cone (“red
weak”)Deutanopia – M-cone (“green weak”)Tritanopia – S-cone
(yellow/blue)
WHAT COLOR BLINDNESS LOOKS LIKE
Normal Deutanopia Tritanopia
WHAT COLOR BLINDNESS LOOKS LIKENormal
Deutanopia Protanpoia
WHAT TO DOIs Color Blindness curable?Medically speaking,
noCan we (UI designers) work around it?Certainly

12. DESIGNING FOR COLOR BLINDNESSAvoid red-on-green at
all costs!Consider using magenta instead of redAvoid using
magenta with blueUse redundant coding of informationUse
color and shape/locationAvoid thin lines / small symbolsFor
color-coded text, use bold fonts
THE END
*
*