lecture 4 task analysis
DESCRIPTION
for hciTRANSCRIPT
LECTURE 4TASK ANALYSIS
DESCRIBING REQUIREMENTS ACTIVITIES Task Analysis & other task descriptionsUse CasesTask analysisWorkflow
1-USE CASE
Description of a user’s goal in using a systemFocuses on user-system interactionOne path through a use case is sometimes called a scenarioOften presented as a series of steps
Diagram of actors and use cases
SYMBOLS
2-TASK ANALYSIS
•Process of analyzing and documenting how people perform their jobs or activities
•Task-subtask decomposition
TASK DECOMPOSITION
Break tasks down into subtasksContinue for as many levels as needed…how many are needed?
Not just for computer tasks, but any sort of activityEasily supports sequential tasksCan support parallel tasks & branchingDifficult to represent exceptions, errors
HIERARCHICAL TASK ANALYSIS (HTA)Graphical notation & decomposition of tasksGoals – what the user wants to achieveTasks – do these to achieve the goalsSubtasks – lower-level tasks
Tasks organized into plansClusters of subtasks with a preferred order and prerequisite conditions
TASK MODEL - BORROW BOOK
Sequences added as annotationsGoal
Tasks tocomplete goal
Subtasks tocarry outone task
ANOTHER REPRESENTATION0. 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
HTA: TYPES OF PLANS
Fixed sequence
Optional tasks
Waiting events
Cycles
Time-sharing
Discretionary/ optional
OTHER TASK REPRESENTATIONS
Flow charts Ordering of task steps, can be complex Includes decisions logic and information
FLOW CHART EXAMPLE
Start
If a=1 a+2
output
Display
display
End
Y
N
ACTIVITY:
Draw Use case Diagram and flow chart
1.Auto sending Birthday wish through Text on desired mob no. at 12:00 AM
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