Ch 4: Discovery

Yonglei Tao

School of Computing & Info Systems

GVSU

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Discovery

Collection Interpretation Documentation

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Exploring the Work Domain Diverse design projects

new designs redesign innovative devices

Different work domains tracking inventory, customer orders, billing,

and websites Various stakeholders

Primary, secondary, facilitator, indirect

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Organizing the Process What/How

What activities are involved and how are they done? Where/When

What impact of physical location is on the work flow? Who/Why

Who is involved Why they are involved Their role in the present work flow How they may respond to any changes implemented

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Collection - Methods

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Collection - Elicitation

Eliciting info from various stakeholders Direct

Interviews Focus groups

Indirect Corporate documentation Logs and notes Questionnaires

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Interpretation

User Analysis Primary Stakeholder Profiles

Task Analysis Storyboarding Use Cases

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User Analysis

Identification of User's Needs

+ Implementation

= Successful User Interface Design

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Understand People

Must know how people work in order to design for them Learn by recognition, not recall Remember things in related groups Have different ways of learning and

communicating Have different strengths and limitations Like to be in control Want to get their work done

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Know Your Users

Skills Training and support availability Frequency of use Vocabulary Environment issues

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User Category

Novice / Occasional Frequent / Intermediate Expert

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Novice/Occasional Users

Expect intuitive, easy to use application Do not want to rely on training or

documentation May need support for multiple input methods Big learning curves are unacceptable

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Frequent/Intermediate Users

Perform routine tasks Such as transaction processing applications

Need quick response Focus on quickness of data entry and review

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Expert Users

Very familiar with software applications and environments

Like to explore May expect higher degree of functionality Comfortable with multi-windowed systems

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User Skill Level Evolution

Skills of an application user evolves over a period of usage

Novice Intermediate Expert

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Different Types of Applications

Life-critical systems Air traffic control, nuclear reactors, power utilities, police & fire dispatch

systems Industrial and commercial uses

Banking, insurance, order entry, inventory management, reservation, billing, and POS

Office, home, and entertainment applications Word processing, electronic mail, computer conferencing, and video game

systems, educational packages, search engines, mobile device, etc. Exploratory, creative, and cooperative systems

Web browsing, search engines, artist toolkits, architectural design, software development, music composition, and scientific modeling systems

Social-technical systems Voting, health support, identity verification, crime reporting

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Outlook Express

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Visual Basic .Net

Blackboard

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User Analysis Matrix

UserProfile

% of totalusers

ApplicationSkill

ApplicationUsage

PlatformPreference

UIPreference

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Primary Stakeholder Profiles

Used to define the target user Context of use Cognitive ability Physical ability Individual profile

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Context of Use

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Example of Context of Use

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Cognitive Ability Profiles

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Physical Ability Profiles

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Individual Profiles

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Task Analysis Understanding requirements

Determine tasks users perform Document how users perform tasks

Deriving user interface design Evaluating user experience

Involve physical and cognitive actions Techniques

Hierarchical Task Analysis (HTA) Storyboarding Use cases

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Task Decomposition

Identify the process Describe the steps Include the following:

Reasons for the actions People who perform the actions Objects they need to use and info

they need to know

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An HTA Diagram

Borrow a book from the library

go to the library

find required book

retrieve book from shelf

take book to counter

321 4

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access catalog

access search screen

enter search criteria

identify required book

note location

plan 0: do 1-3-4. If book isn’t on the shelf expected, do 2-3-4.

plan 2: do 2.1-2.4-2.5.If book not identified from information available, do 2.2-2.3-2.4-2.5

2.1 2.2 2.3 2.4 2.5

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Textual Representation of HTA

0. In order to borrow a book from the library 1. go to the library 2. find the required book

2.1 access library catalogue2.2 access the search screen2.3 enter search criteria2.4 identify required book 2.5 note location

3. go to correct shelf and retrieve book4. take book to checkout counter

Plan 0: do 1-3-4. If book isn’t on the shelf expected, do 2-3-4Plan 2: do 2.1-2.4-2.5. If book not identified do 2.2-2.3-2.4

Task Sequence

A plan is to describe in what order and under what conditions subtasks are performed

Types of plan

fixed sequence - 1.1 then 1.2 then 1.3

optional tasks - if the pot is full 2

wait for events - when kettle boils 1.4

cycles - do 5.1 5.2 while there are still empty cups

time-sharing - do 1; at the same time ...

discretionary - do any of 3.1, 3.2 or 3.3 in any order

mixtures - most plans involve several of the above

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Relative Task Frequencies

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HTA – Understanding Requirements

Start with a user goal and identify the main tasks for achieving it

Break a task down into subtasks, then sub-sub-tasks and so on Focus on physical and observable actions Determine atomic actions

Group tasks as plans that specify how they might be performed in practice

Scenarios for “Bake a Cake”

“Bake a Cake” (Cont.)

“Bake a Cake” (Cont.)

HTA - Deriving UI Design

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Evaluating User Experience

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An Example Some years ago the US telephone company NYNEX were

intending to install a new computer system to support their operators.

Before installation a detailed GOMS analysis was performed taking into consideration the cognitive and physical process involved in dealing with a call.

The task analysis was used to determine the critical path, and hence the time to complete a typical task.

It was discovered that rather than speeding up operations, the new system would take longer to process each call. The new system was abandoned before installation, leading to a saving of many millions of dollars.

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Storyboarding Using a series of pictures to describe a

particular process or work flow Study existing work flows or generate

requirements. Facilitate task decomposition Brainstorm alternative ways of completing tasks

Used early in design

Use Cases A story about how a user will use the system

to do what one needs Defines a sequence of interactions between one

or more actors and the system Describes requirements in context Focuses on functional requirements

Writing use cases is also a requirements elicitation process

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