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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