Hci activity#3

Activity #3
Computer in HCI
Interaction
Models of Interaction
Interaction Styles
Ergonomics
Paradigms of Interaction
Human Computer Interaction(HCI)- Itec 332

In thisActivity you will :
Understand the computer and associated input-
output devices and investigates how the technology
influences the nature of the interaction and style of
the interface.
Identify Interaction models and different styles of
interaction
Understand paradigm shifts of interaction
technologies.
2 Compiled by: DesalegnAweke. Interaction

Introduction
 To understand human–computer interaction
o …we need to understand computers- limitations,
capacities, tools, platforms
o understand people- psychological, social aspects and human
error
o and their interaction
3 Compiled by: DesalegnAweke. Interaction

InteractionCompiled by: DesalegnAweke.4
Computer
In fact, the most sophisticated machines are worthless unless
they can be used properly by men.

Cont’d
 Computer system is made up of various elements
 Each of these elements affects interaction
 Input devices – text entry and pointing
 Output devices – display, digital paper
 Virtual Reality – special interaction and display devices
 Physical interaction – e.g. sound and haptic
 Paper – as output (print) and input (scan)
 Memory – RAM & permanent media, capacity and access
 Processing – speed of processing, networks

Cont’d
 The human user uses the computer as a tool to perform, simplify or
support a task. In order to do this the user must communicate his
requirements to the computer.
 There are a number of ways in which the user can communicate
with the system.
Long ago in a galaxy far away … batch processing
 punched card stacks or large data files prepared
 long wait ….
 line printer output
… and if it is not right …
 This approach does involve an interaction between the user
and computer but does not support many tasks well

Cont’d
Now most computing is interactive, such as direct manipulation
and the applications of virtual reality.
 rapid feedback
 the user in control (most of the time)
 doing rather than thinking …

The Interaction
 The communication between the user and the system.
 Interaction refers to a dialogue generated by the command and
data, input to the computer and the display, output of the
computer and the sensory/perceptual input to the human and
motor response output of the human.
 There are number of ways in which the user can communicate
with the system, batch input, direct manipulation etc.
 The interaction takes place within a social and organizational
context that affects both user and system.

The terms of interaction
 Traditionally, the purpose of an interactive system is to aid a user
in accomplishing goals from some application domain.
 Domain
 defines an area of expertise and knowledge in some real-world
activity(i.e, area of work understudy).
 Eg. Graphic design
 Tasks
 Are operations to manipulate the concepts of a domain
 How you go about doing it? Ultimately in terms of operations or
actions
 Eg. Select fill form, click over triangle

Cont’d
 Goal
 A goal is the desired output from a performed task (what
you have achieve).
 For example, is the construction of a specific geometric
shape with particular attributes on the drawing surface. i.e.
create a solid red triangle

Models of Interaction
 Interaction models enable us:-
 To understand exactly what is going on in the interaction and
identify the likely root of difficulties
 To compare different interaction styles and to consider
interaction problems
 To address the translations between what the user wants and
what the system does.
 To identify and evaluate components of the interaction, and at
the physical, social and organizational issues that provide the
context for it.

Cont’d
 We begin by considering the most influential model of interaction,
Norman‘s execution–evaluation cycle(Donald Norman‘s Model);
 Then we look at another model which extends the ideas of
Norman‘s cycle which is interaction framework (Abowd and Beale‘s
framework).
 Both of these models describe the interaction in terms of the goals
and actions of the user.
 Interaction aids a user in accomplishing goals from a domain.
 Tasks manipulate concepts, and a goal is the desired output from a
task.
 An intention is a specific action required to meet the goal.!
 The System uses a core language, while the User uses a task
language to describe relevant concepts.

Execution–Evaluation cycle(Norman’s model)
 Norman‘s model of interaction is perhaps the most influential in
HCI, possibly because of its closeness to our intuitive understanding
of the interaction between human user and computer.
 This model concentrates on user‘s view of the interface.
 User formulates a plan, which is then executed at the computer
interface.
 When the plan, has been executed, the user observes the computer
interface to evaluate the result of the executed plan, and to
determine further actions.

Cont’d
 Norman‘s model of interaction has two phases: execution and
evaluation.These can then be subdivided into further stages.
 The plan formulated by the user is executed by the computer.
When finished, the user evaluates the results and determines the
further actions.
System
Evaluation
Execution
Goal

Cont’d
 Norman‘s model of interaction has seven stages.These are:-
1. Establishing the goal.
2. Forming the intention.
3. Specifying the action sequence.
4. Executing the action.
5. Perceiving the system state.
6. Interpreting the system state.
7. Evaluating the system state with respect to the goals and
intentions.

Cont’d

Cont’d
 Each stage is an activity of the user.
 First the user forms a goal.
 This is the user‘s notion of what needs to be done and is framed in
terms of the domain, in the task language.
 Needs to be translated into the more specific intention, and the
actual actions that will reach the goal, before it can be executed by
the user.
 The user perceives the new state of the system, after execution of
the action sequence, and interprets it in terms of his expectations.
 If the system state reflects the user‘s goal then the computer has
done what he wanted and the interaction has been successful;
 Otherwise the user must formulate a new goal and repeat the cycle

Cont’d
 Norman uses this model of interaction to demonstrate why some
interfaces cause problems to their users.
 He describe this in terms of :-
 Gulf of Execution
 Gulf of Evaluation
 As noted earlier, the user and the system do not use the same
terms to describe the domain and goals – remember that we
called the language of the system the core language and the
language of the user the task language.

Cont’d
 The gulf of execution is the difference between the user‘s
formulation of the actions to reach the goal and the actions
allowed by the system.
 If the actions allowed by the system correspond to those
intended by the user, the interaction will be effective.
 The interface should therefore aim to reduce this gulf.

Cont’d
 The gulf of evaluation is the distance between the physical
presentation of the system state and the expectation of the
user.
 Psychological gap that needs to be crossed in order to
interpret a user interface!
 If the user can readily evaluate the presentation in terms of
his goal, the gulf of evaluation is small.
 The more effort that is required on the part of the user to
interpret the presentation, the less effective the interaction.

Cont’d
Human errors:- Slips and Mistakes!
 Human errors are often classified into slips and mistakes.We
can distinguish these using Norman‘s gulf of execution.
 Slips
 If you understand a system well you may know exactly what to
do to satisfy your goals – you have formulated the correct action.
 However, perhaps you mistype or you accidentally press the
mouse button at the wrong time.These are called slips; you have
formulated the right action, but fail to execute that action
correctly.

Cont’d
 Mistakes
 if you don‘t know the system well you may not even formulate the
right goal.
 For example, you may think that the magnifying glass icon is the
‗find‘ function, but in fact it is to magnify the text.This is called a
mistake.
 Fixing things? or to fix human errors --
 Slip - better interface design
 Mistake - better understanding of system

The interaction framework (Abowd & Beale’s framework )
 Norman‘s model concentrates on the user‘s view of the interaction.
 It does not attempt to deal with the system‘s communication through
the interface
 An extension of Norman‘s model, proposed by Abowd and Beale,
addresses this problem.
 The interaction framework attempts a more realistic description of
interaction by including the system explicitly, and breaks it into four
main components.
 System, User, Input and Output.

Cont’d
As the interface sits between the User and the System, there are four
steps in the interactive cycle, each corresponding to a translation
from one component to another

Cont’d
 The User begins the interactive cycle with the formulation of a
goal and a task to achieve that goal.
 user intentions
 translated into actions at the interface
 translated into alterations of system state
 reflected in the output display
 interpreted by the user
 General framework for understanding interaction
 Identifies all major components involved in interaction
 Allows comparative assessment of systems

Ergonomics
 Ergonomics (or human factors) is traditionally the study of the
physical characteristics of the interaction:
How the controls are designed,
The physical environment in which the interaction takes place
and
The layout and physical qualities of the screen.
 Primary focus is on user performance and how the interface
enhances from this.
 Inappropriate placement of controls and displays can lead to
inefficiency, frustration and sometimes dangerous situations.

Cont’d
 Consider a few of the issues addressed by ergonomics
 The arrangement of controls and displays,
 The physical environment,
 The health issues and
 The use of color.
 arrangement of controls and displays
e.g. controls grouped according to function or frequency of use,
or sequentially
 surrounding environment
 The system‘s design needs to fit the users size, position
(sitting/standing), comfort and safety.
e.g. seating arrangements adaptable to cope with all sizes of user

Cont’d
 health issues
e.g. physical position, environmental conditions
(temperature, humidity), lighting, noise,
 use of colour
 The colors should correspond to common conventions
and user expectations.
E.g. use of red for warning, green for okay,
awareness of colour-blindness etc.
 Ergonomics contribution to HCI is in determining constraints
on the way we design systems and suggesting detailed and
specific guidelines and standards for our design

Interaction Styles/ interface styles
 Interaction can be defined as a dialog between the computer and the user.
 The choice of interface style can have a profound effect on the nature of
this dialog.
 Interface types
 1980s interfaces
 Command,WIMP/GUI
 Advanced graphical (multimedia, virtual reality, information
visualization)
 Web, Speech (voice), Pen, gesture, and touchAppliance
 Mobile, Multimodal, Shareable,Tangible
 Augmented and mixed reality
 Wearable, Robotic

Cont’d
Interface style
•Command line Interface
•Menu- driven Interface
•Forms Interface
•WIMP
•Natural language
Expressive
Intuitive
There are a number of common interface styles including:-

Command line interface
 Way of expressing instructions to the computer directly
 Function keys, single characters, short abbreviations, whole
words, or a combination
 Suitable for repetitive tasks
 Better for expert users than novices
 Offers direct access to system functionality
 Command names/abbreviations should be meaningful!
 Typical example: the Unix system, linux etc..

Cont’d
• Command entry: human user issues commands directly to
the computer.
• Many different options customize commands (expressive).
• Requires user to learn large numbers of commands and
options (not intuitive).

Menu Interface
 In a menu-driven interface, set of options displayed on the
screen
 The options are visible
 less recall - easier to use
 rely on recognition so names should be meaningful
 Selection by:
 numbers, letters, arrow keys, mouse
 combination (e.g. mouse plus accelerators)

Cont’d
Menu-driven interface
• Menu interface: commands
organized into logical groups
(more intuitive than command
entry)
• A submenu can be used to
present further related list of
sub-functions or options
• Menu structure limits range of
options (less expressive than
command entry)
• Restricted form ofWIMP

Forms Fill
• Form interface: presents
specific questions to which a
user must respond in order
to perform some task.
• Intuitive, since users are led
step by step through
interaction.
• Not expressive, since form
allows access to only a few
specialized commands

Natural language
 Familiar to user
 Speech recognition or typed natural language
 Problems
 Vague
 Ambiguous
 Hard to do well!
 Solutions
 try to understand a subset
 pick on key words

WIMP Interface (GUI)
Windows
Icons
Menus
Pointers
… or windows, icons, mice, and pull-down menus!
 Together, these elements of theWIMP interfaces are called
widgets, and they comprise the toolkit for interaction between
user and system.
 Default style for majority of interactive computer systems,
especially PCs and desktop machines

Cont’d
 Windows
 could be scrolled, stretched, overlapped, opened, closed, and moved
around the screen using the mouse
 Icons
 represented applications, objects, commands, and tools that were
opened when clicked on
 Menus
 offering lists of options that could be scrolled through and selected
 Pointing device
 a mouse controlling the cursor as a point of entry to the windows,
menus, and icons on the screen

Cont’d
 WIMP: stands for windows, icons, menus, pointers
 WIMP interfaces are familiar as they are the basis of most
desktop-computer operating systems

Some other Interaction styles
 Question/answer and query dialogue
 Point and click
 Direct Manipulation
 Three–dimensional interfaces
 Gesture Recognition
 Gaze Detection
 Speech and Speaker Recognition
 Pen based Interaction
 MotionTracking sensors and Digitizers
 Taste and smell sensors

The Context of interaction
In reality, users work within a wider social and organizational
context.
Interaction affected by social and organizational context
 other people
 desire to impress, competition, fear of failure
 motivation
 fear, allegiance, ambition, self-satisfaction
 inadequate systems
 cause frustration and lack of motivation
 The social and organizational factors may have an influence on the user‘s
interaction with the system.These may not be factors over which the
designer has control.

Paradigm for Interaction
 Paradigm refers to a particular approach that has been
adopted by a community in terms of shared assumptions,
concepts, values and practices
 Questions to be asked and how they should be framed
 Phenomena to be observed
 How findings from experiments are to be analyzed and
interpreted

Why Study Paradigms?
Concerns
 How can an interactive system be developed to ensure its
usability?
 How can the usability of an interactive system be
demonstrated or measured?
History of interactive system design provides paradigms for
usable designs
What are Paradigms?
 Predominant theoretical frameworks or scientific world views
 E.g.,Aristotelian, Newtonian, Einsteinian (relativistic)
paradigms in physics

Cont’d
 Understanding HCI history is largely about understanding a
series of paradigm shifts
 Not all listed here are necessarily ―paradigm‖ shifts, but are at
least candidates
 History will judge which are true shifts

Paradigms of interaction
 New computing technologies arrive, creating a new
perception of the human—computer relationship.
 We can trace some of these shifts in the history of interactive
technologies.
 The initial paradigm- Batch processing
 Complete jobs processed individually.

Cont’d
 Example : Paradigm Shifts
 Batch processing- Interactive computing
 Time-sharing- Interactive computing
 Networking- Community computing
 Graphical displays- Direct manipulation
 Microprocessor- Personal computing
 WWW or Internet ofThings(IOT)-Global information

Paradigms in HCI
 In 80s:
 Single user on the desktop
 In the mid 90s:
 Virtual reality, multimedia, agent interfaces, ubiquitous
computing.

Ubiquitous Computing
 Any computing technology that permits human interaction away
from a single workstation
 filling the real world with computers
 What HCI is in this context?
New thinking
 How to access and interact with information in any situation?
 Designing user experiences
 The right form to provide contextually relevant information
 Ensuring that information is secure and trustworthy

Virtual reality and virtual environment
 Enabling users to interact with objects and navigate in 3D space
 Create highly engaging user experiences
Multimodal interction
 Multimodality is the use of two or more modes of input for the exchange of
information.

Thank you

Hci activity#3

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