On%20Human%20Computer%20Interaction,%20HCI

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On Human Computer Interaction, HCI

• Dr. Saif al Zahir
• Electrical and Computer Engineering Department
• UBC

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Human Computer Interaction HCI

• HCI is the study of people, computer technology,
  and the ways these influence each other.
• We study HCI to determine how we can make this
  computer technology more usable for people.
• HCI is a multidisciplinary practice
• Engineering
• Computer Science
• Sociology
• Cognitive psychology
• Ergonomics

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Why HCI ?..

• Numerous Applications ..
• E-commerce
• Computer-aided surgery (medical applications)
• Remote learning (distance education)
• Computer aided Planning, Manufacturing, ...
• Tourism
• GIS
• you name it ...

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H-C strengths and weaknesses

• Human
• Powerful pattern recognition
• powerful selective attention
• capacity to learn
• infinite-capacity LTM
• rich multikeyed LTM

• Computer
• High-capacity memory
• permanent memory
• very fast processing
• error-free processing
• reliable memory access

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H-C strengths and weaknesses

• Low capacity working memory
• fast decaying working memory
• slow processing
• error prone processing
• unreliable access to LTM

• Simple template matching
• limited learning capacity
• limited capacity LTM
• limited data integration

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HCI Objectives

• Interaction between a human user and a computer
  system via the medium of an interface.
• - usability criteria.
• HCI makes use of new and novel techniques and
  technologies to make working with computers
  easier and more productive.
• HCI aims to achieve more usable systems and more
  satisfied users.
• Pragmatics legislative, financial and usability
  constraints as well as safety-critical.

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Door
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Good User Interface
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What is an Interface ?..

• Possible Definitions
• A collection of input and output devices
• Surface forming common boundary of two systems
• A place for conversation
• Place where the interaction occur between two
  systems
• All the information channels that allow the user
  and the object to communicate

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Why High quality UI ??..

• Whether a user enjoy or despise a system
• Whether a system succeeds or fails in a market
• Example 1 Nuclear power plant monitoring
  system. A poor UI can contribute to and even
  cause accident of catastrophic nature
• Example 2 Air Traffic Control

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Styles of UI

• 1. What you see is what you get (WYSIWYG)
• 2. Direct Manipulation
• the objects, attributes, or relations that can
  be operated on are represented visually. Use a
  mouse to invoke.
• 3. Iconic
• A pictorial representation of an object, an
  action, a property, or some other concept
• recognition, remembering, and discrimination

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Main Objectives in User Interface Design

• 1. Increase the speed of learning
• measure how long a new user takes to achieve
  certain level of proficiency.
• 2. Speed of Use
• measure how long an experienced user require
  to perform certain task with a system
• 3. Reduction of errors
• measure the number of user errors per
  interaction
• 4. Attractive to buyers and users
• target computer naive users

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UI as a system

• 1. Interaction devices (input / output)
• 2. Interaction techniques
• ways to use input devices to enter information
  into the computer
• 3. Interaction tasks
• classify the fundamental types of information
  entered with interaction techniques
• - position
• - text
• - select
• - quantify

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UI Design Methods

• There is no cookbook approach that ensure good
  interface design
• Why ??
• 1. Some of the design principles are based on
  experts experience and logical deduction
  from related fields such as cognitive psychology,
  rather than hard data
• 2. For any given design problem, guidelines will
  usually come in direct conflict with each other,
  and there are no algorithms for making the
  trade-offs
• UI design is a matter of Compromise Trade-off

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Examples on conflicting requirements Want
powerful functionality But simple and clear
interfaceWant ease of use But also ease of
learningWant consistency across all aspects of
the interface But optimize operationWant
intelligent and sophisticated interface But good
performance and low cost.Results We need
methods to solve these conflicting requirements
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Correspondence
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Graphic Interface
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Theories of Human Behavior

• Psychological
• Sociological
• Anthropological
• Develop a Model to help us understand and
  predict human behavior
• Provide simple examples of predictions

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Theories of Human Social Behavior

• 1. Explanatory theories
• 2. Empirical theories
• 3. Dynamic Models
• Study them and the way they support design

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1. Explanatory theories

• Explains observed human behavior
• explain things we see people doing
• help in evaluation (i.e., newly installed sys.)
• why system impact is different from expected
• study users and analyzing their needs
• Example 1 Users using keyboard shortcuts more
  than expected cause of high latencies in menu
  display
• Example 2 Air traffic controllers failing to
  trust a system because it undermined their
  team-oriented working style.

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2. Empirical Laws

• Empirical Laws offer simple quantitative
  prediction of human performance
• Example Hicks Law (1952)
• The time T taken to choose between a number of
  alternative targets is a function of the number
  of the targets n, and is related logarithmically
  
• Where k is a constant

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2. Empirical Laws

• Examples
• the correlation between size of menu and the time
  to make a selection
• cycle times of the human brain
• the time taken to move the mouse to a target of a
  given size from a given distance away.

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3. Dynamic Models

• Models that predict how a whole sequence of
  actions (steps) will be performed
• models which predict the sequence of actions a
  user will take
• model which predict the level of performance if a
  given sequence of actions is taken by the user

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3. Dynamic Models

• Predict the speed with which the user can
  perform an activity
• example keyboard interaction speed
• simple dynamic model to predict the speed of
  operation of keyboard-based user-interface
• Cycle times (can use this for the zigzag example)
• perceptual 50-200 msec Average 100 ms
• cognitive 25-170 msec Average 70 ms
• motor 70-100 msec Average 70 ms

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3. Dynamic Models

• Fitts Law
• This Law tells us how long it will take a user
  to hit a target of certain diameter, W, with a
  pointing device that is a certain distance , A,
  away. It uses the information processing model.

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Design of the User Interface

• Factors that must be considered
• 1. How menus are to be organized.
• 2. How the graphics package is to respond to
  the input and errors.
• 3. How the output display is to be organized
• 4. How the package to be documented and
  explained to the user

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Components of the User Interface

• User Model
• Command Language
• Menu Format
• Feedback Methods
• Output Format.

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1. User Model

• Provides definition of the concepts involved in
  the graphics package
• Helps the user to understand how the package
  operates in terms of application concepts
• Explain to the user what type of objects can be
  displayed and how they can be manipulated.

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2. Command Language

• Must be as natural as possible for the user to
  learn
• minimize memorization
• each operation in a command language should be
  structured so as to be easy to understand and
  remember
• no abbreviation (minimum). Ex. Select - Object is
  easier to remember than SO
• small set of operation

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3. Menu Design

• Most computer graphics make use of menus
• Cut down on the amount of memorization
• Preventing users from selecting invalid options
• menus can easily be changed to accommodate
  different applications, whereas function keys
  must be reprogrammed and relabled if they are
  changed
• Menus with fewer options are more effective
• Placed on one side of the screen
• Can develop multilevel structure menu
• limit the number of levels

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4. feedback

• The system must have a continual interactive
  dialogue and inform the user what the system is
  doing at each step.
• Special symbol can be designed for different
  types of feedback
• Example a blinking at work sign to tell the
  user that the system is still processing
• Example Mis-spelled words in Window 9x are
  underlined with red color

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5. Output Format

• Information presented to the user
• 1. Output pictures
• 2. Menus
• 3. Messages
• 4. Other forms of dialogue generated by the
  system

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5. Output Format-2

• Format Design to achieve greatest effectiveness
• 1. Icon and symbol shapes
• Simple and clear picture of the object or
  operation they represent
• 2. Screen Layout
• main components
• (a) main area
• (b) Menu area
• (c) Display prompts and feedback area.

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5. Output Format-3

• 1. Flexibility must be given to the user
• 2. Introduce overlapping window areas
• 3. Zoom capability to expand or enlarge portion
  of a picture

Work Area
Menu
Prompts and feedback messages
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wisdom

• No matter how cool is your interface, less of it
  would be better.
• Alan Cooper,
• Father of Visual Basic

• We think logically not visually
• We base our design on our own knowledge rather
  than the users
• We make our programs take control
• We think in generalities, not specific

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Human Information Processing System, HIPS

• Basic Components
• Memory (short-term and long-term)
• Input (eyes, ears, touch)
• Output (hands, voice, eyes)
• Processes (executive control unit, pattern
  recognition, knowledge and skills

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Human Memory

• Short Term Memory, STM
• memory buffer with low capacity (7 2 units)
• a brief trace duration (few seconds)
• Can help STM by Grouping stored information.
• Example remembering 111-2222 vs. 359-2741
• Long Term Memory, LTM
• powerful storage
• permanent in duration
• information is stored in a very rich, complex,
  and dynamic structure (this requires
  reorganization constantly)
• retrieval processes are slow, unreliable, and
  difficult. (need more concentration to get
  information from LTM)

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Human Information Processor Model Based on
classic information processing model (a) set of
memories and processors (b) three interacting
subsystems - perceptual - motor and -
cognitive Principle of operation is the
recognize-act cycle (c) properties
that can be measured include -
processor cycle time - memory decay rate -
memory capacity
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Types of Theory in HCI

• Exploratory theories
• To explain observed human behavior
• can provide useful insights in design
• lack predictive power
• Empirical laws
• Simple quantitative predictions of human
  performance (example Fitts law for the time
  taken to point to a target of a particular size).

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• Usability
• The term usability has become central to the
  field of HCI. It can be defined very
  generally as
• Making systems safe, easy to learn and easy to
  use.
• A more formal definition is
• The degree to which specific users can achieve
  specific goals in a particular environment with
  efficiency, effectiveness, satisfaction.

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Theory of Action Action is a series of
progressive mental steps, resulting in a physical
action. Outcome of a physical action at the
interface is mentally evaluated in a series of
steps. Stage 1- Mental Steps before
physical action deciding
planning translating
executing Stage 2 -
Corresponding steps after action perceiving
recognizing interpreting evaluating
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Task Performance

• 7-Steps for Task Performance
• Execution
• Establishing the Goals
• Forming the intention
• Specifying the action (Planned action sequence
  corresponding to intention)
• Executing the action
• Evaluation
• Perceiving the system state
• Interpreting the system state (trying to make
  sense of it as in expectation)
• Evaluating the outcome with respect to the goal
  and intention

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Gulf of Execution and Gulf of Evaluation

• Gulf of Execution
• Is the difference between the intention of the
  person and the perceived allowable action.
• Gulf of Evaluation
• Is the difference between the cisible state of
  the system and the correct interpretation of the
  state of the system.

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• Uses of GOMS
• Goals, Operations, Methods, and Selection Rules
• Used in
• comparing alternative systems.
• describing how same task is performed
  in different systems (keystroke method can be
  used to work out which system is fastest.
• developing training materials.
• describing the most efficient way to
  perform tasks.
• evaluating the consistency and
  completeness of a design.
• Advantages
• cheap and relatively quick to carry
  out.
• systems that dont yet exist, but which
  are being designed, can be evaluated.

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Methodology Phases

• Scoping
• Functional Specifications
• Design
• Development
• Testing/Implementation

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• Scoping

Adding Human factors to Software Development
Scoping
Business Requirement Analysis
Business Definition
Application Project Team
Project Plan
User Profile
User Interface Group
HW SW Definition
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Developments in the Interface 50s -
Interface with engineers at the hardware (level
1). interface was at the hardware level.
60/70s- interface with high level programming
(level 2). software engineering and management.
70/90s Interface at the terminal (level
3). interactivity, command languages.
80s - Interface at interaction dialogue (level
4). GUIs, colour, sound, 3-D, animation.
90s - Interface at the work setting (level 5).
networked systems, VR.