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Ch 4: Discovery Yonglei Tao School of Computing & Info Systems GVSU
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2 Discovery Collection Interpretation Documentation
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3 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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4 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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5 Collection - Methods
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6 Collection - Elicitation Eliciting info from various stakeholders Direct Interviews Focus groups Indirect Corporate documentation Logs and notes Questionnaires
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7 Interpretation User Analysis Primary Stakeholder Profiles Task Analysis Storyboarding Use Cases
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8 User Analysis Identification of User's Needs + Implementation = Successful User Interface Design
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9 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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10 Know Your Users Skills Training and support availability Frequency of use Vocabulary Environment issues
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11 User Category Novice / Occasional Frequent / Intermediate Expert
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12 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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13 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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14 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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15 User Skill Level Evolution Skills of an application user evolves over a period of usage Novice Intermediate Expert
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16 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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17 Outlook Express
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18 Visual Basic.Net
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Blackboard 19
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20 User Analysis Matrix
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21 Primary Stakeholder Profiles Used to define the target user Context of use Cognitive ability Physical ability Individual profile
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22 Context of Use
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23 Example of Context of Use
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24 Cognitive Ability Profiles
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25 Physical Ability Profiles
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26 Individual Profiles
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27 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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28 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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29 An HTA Diagram Borrow a book from the library go to the library find required book retrieve book from shelf take book to counter 3214 0 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 2.12.22.32.42.5
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30 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 catalogue 2.2 access the search screen 2.3 enter search criteria 2.4 identify required book 2.5 note location 3.go to correct shelf and retrieve book 4.take book to checkout counter 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 do 2.2-2.3-2.4
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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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32 Relative Task Frequencies
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33 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
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Scenarios for “Bake a Cake”
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“Bake a Cake” (Cont.)
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HTA - Deriving UI Design 37
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Evaluating User Experience 38
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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. 39
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40 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
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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 41
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