User Interaction Design

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User Interaction Design

• Representing User Interactions

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Design Representation

• Design
• Creative, mental, problem-solving process
• Representation
• Physical process of capturing or recording a
  design

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Design Representations

• Means by which interaction designs are
  communicated and documented.
• Design representations are communicated between
• Designer and developer (maybe others)
• Not the User (in most cases)

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Design Representations

• Constructional Representations
• Interactions described from the systems view
  point.
• State Transition diagrams
• Event-based mechanisms
• Object Oriented mechanisms

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Design Representations

• Behavioral Representations
• User Centered and Task/Goal Oriented.
• Task Analysis, user modeling, function analysis
  are all behavioral activities
• Example Methods
• Command Language Grammar
• Keystroke Level Model
• Task Action Grammar
• GOMS (Goals, Operators, Methods Selection)
• User Action Notation (UAN)

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User Interaction Design

• Each Behavioral design must be translated into a
  Constructional Design
• Result is the User Interaction Design
• User Interaction Design is created by the
  designer and given to the developer.

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User Action Notation

• User and Task Oriented Notation that describes
  physical behavior of the user and interface as
  task are being performed.

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User Action Notation

• Interfaces are represented as quasi-hierarchical
  structures of asynchronous tasks.
• User actions cause state changes in the interface.

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User Action Notation

• UAN consists of
• Task Descriptions
• Scenarios
• Discussion Notes
• State Transition Diagrams
• Uses special Notation to describe tasks

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UAN Selecting A File

• Move the cursor to the file icon.
• Press and immediately release the left mouse
  button.

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UAN Selecting A File

• file icon
• Mv

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User Action Notation

• Advantage of UAN
• Takes less space on paper.
• If you know, it saves time.

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User Action Notation

• Problems with UAN
• New language for the developer.
• Cryptic notation.
• If you dont know it, it takes more time.
• No standard notation.

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User Action Notation Modified

• UAN consists of
• Task Descriptions
• Scenarios
• Discussion Notes
• State Transition Diagrams
• Eliminate special Notation

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Task Descriptions

• Identify all of the tasks the system or product
  must support.
• Occurs in Feasibility and Analysis Stage of
  Software Development.

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Scenarios

• Create User Scenarios that support each task from
  the Task Descriptions.
• Occurs in Analysis and Design Stage of Software
  Development.

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Discussion Notes

• Any special observations, requirements or
  hypothesis that designer has are noted.
• Occurs in everywhere in Software Development.

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State Transition Diagrams

• Finite State Machines
• Graph of the system that identifies user
  interactions.
• Occurs in Design before Development.
• Includes graphs and screen images.

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State Transition Diagrams

• Graphs with Nodes and Edges.
• Nodes
• Represent interface states.
• Image of interface should be included.
• Edges
• Appear between nodes.
• Represent changes in interface state.

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State Transition Diagrams

• Each interface has a State Transition Diagram.
• The system is a collection of interfaces,
  therefore, it is also a collection of State
  Transition Diagrams
• Can become very complex very quick.

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State Transition Diagrams

• Each interface has a State Transition Diagram.
• The system is a collection of interfaces,
  therefore, it is also a collection of State
  Transition Diagrams
• Can become very complex very quick.

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User Interaction Design

• Example
• Login Interface

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User Login Interface
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Top path
Bottom path
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Top Path
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User enters login name.
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User enters password.
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User presses submit.
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Bottom Path
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User enters password.
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User enters login name.
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User presses submit.
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Top path
Bottom path
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User Interaction Design

• Task Descriptions
• Scenarios
• Discussion Notes
• State Transition Diagrams