User Interaction Design Representing User Interactions

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

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)

Design Representations Constructional Representations –Interactions described from the system’s view point. State Transition diagrams Event-based mechanisms Object Oriented mechanisms

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)

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.

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

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

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

UAN: Selecting A File 1.Move the cursor to the file icon. 2.Press and immediately release the left mouse button.

UANUAN: Selecting A File 1.~[file icon] 2.Mv^

User Action Notation Advantage of UAN 1.Takes less space on paper. 2.If you know, it saves time.

User Action Notation Problems with UAN 1.New language for the developer. 2.Cryptic notation. 3.If you don’t know it, it takes more time. 4.No standard notation.

User Action Notation Modified UAN consists ofUAN –Task Descriptions –Scenarios –Discussion Notes –State Transition Diagrams Eliminate special Notation

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

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

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

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

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.

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.

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.

User Interaction Design Example Login Interface

User Login Interface

StartPasswordLoginPasswordLoginEndSubmit Top path Bottom path

Top Path StartPasswordLoginEndSubmit

User enters login name.

User enters password.

User presses submit.

Bottom Path StartLoginPasswordEndSubmit

User enters password.

User enters login name.

User presses submit.

StartPasswordLoginPasswordLoginEndSubmit Top path Bottom path

Review of Computational Theory Relationship to Web Design

Automatic Door/FA Front pad Rear pad closedopen Front Neither Front, Rear, Both Rear, Both, Neither Chuck Allison, UVSC,

Successful Path A successful path through a transition graph is a series of edges forming a path beginning at some start state (there may be several) and ending at a final state abba aa b Free Ride abbab… abbaa… abbababba A Lambda transition occurs when you get a free transition that was not initiated by user or system action/interaction. Move on a whim (w/o consuming input). Chuck Allison modified by Seals

Example (p. 84) a,ba,b ab bb b bbb a aa a a b b - + Cohen Ch6-Chuck Allison,

User Interaction Design 1.Task Descriptions 2.Scenarios 3.Discussion Notes 4.State Transition Diagrams