TASK ANALYSIS

1. TASK ANALYSIS 공병돈

2. Overview Task analysis ? Study of the way people perform tasks with existing systems . Technics – Decomposition Taxonomic classification Listing things used & actions performed Source of Information – Existing documentation Observation Interviews Using to Design – Manual & Documentation New systems

3. Introduction Process of Analyzing the way people perform their job • what people do • what things they work with • what they must know Ex) in order to clean the house • get the vacuum cleaner out • fix the appropriate attachments • clean the rooms • when the dust bag gets full, empty it • put the vacuum cleaner and tools away must know about: • vacuum cleaners, their attachments,dust bags, cupboards, rooms etc.

4. Differences Between task analysis and other technics

5. Approaches to task analysis • Task decomposition - splitting task into (ordered) subtasks • Knowledge based techniques • - what the user knows about the taskand how it is organised • Entity/object based analysis • - relationships between objects, actions and the people who perform them

6. Task Decomposition Aims : Describe the actions people do Structure them within task subtask hierarchy Describe order of subtasks Hierarchical Task Analysis (HTA) 0. in order to clean the house 1. get the vacuum cleaner out 2. get the appropriate attachment 3. clean the rooms 3.1. clean the hall 3.2. clean the living rooms 3.3. clean the bedrooms 4. empty the dust bag 5. put vacuum cleaner and attachments away ◈ Plan 0 do 1 - 2 - 3 - 5 in that order. when the dust bag gets full do 4 ◈ Plan 3 do any of 3.1, 3.2 or 3.3 in any order depending on which rooms need cleaning

7. Task Decomposition Stopping rule -> Depend on purpose of task analysis P*C rule Complex motor response orInternal Decision Making 0. inan emergency 1. read the alarm 2. work out appropriate corrective action 3. perform corrective action

8. Task Decomposition Make Pot

9. Task Decomposition time-sharing cycles wait for events optional tasks fixed sequence mixtures

10. Waiting … • is waiting part of a plan?… or a task? • generally • task – if ‘busy’ wait • you are actively waiting • plan – if end of delay is the event • e.g. “when alarm rings”, “when reply arrives”

11. Approaches to task analysis • Task decomposition - splitting task into (ordered) subtasks • Knowledge based techniques • - what the user knows about the taskand how it is organised • Entity/object based analysis • - relationships between objects, actions and the people who perform them

12. Knowledge-Based Analysis • Listing all objects & actions -> Build texonomy • Aim : Understand needed knowledge about task • Help production teaching material • Common knowledge between differ task wash/wipe wipers front wipers, rear wipers washers front washers, rear washers heating temperature control, air direction, fan, rear screen heater parking hand brake, door lock radio numerous! motor controls steering steering wheel, indicators engine/speed direct ignition, accelerator, foot brake gearing clutch, gear stick lights external headlights, hazard lights internal courtesy light

13. Knowledge-Based Analysis • Three types of branch point(TDH:Task description hierachy)) • XOR : normal taxonomy -> ( ) • AND : multiple classifications -> / • OR : weakest case -> { } Kitchen item AND /____shape XOR / |____dished mixing bowl, casserole, saucepan, soup bowl, glass / |____flat plate, chopping board, frying pan / /____function OR {____preparation mixing bowl, plate, chopping board {____cooking frying pan, casserole, saucepan {____dining XOR |____for food plate, soup bowl, casserole |____for drink glass Plate as Kitchen item/shape(flat)/function{preparation,dining(for food)}/

14. Knowledge-Based Analysis TDH in actions • kitchen job OR • |____ preparation beating, mixing • |____ cooking frying, boiling, baking • |____ dining pouring, eating, drinking What action can do we do with a choping board? We Can capturing all action of task !! Generification – do not use complete KRG Kitchen item/shape(flat)/ Function {preparation,dining(for food)}/ Kitchen item/function{preparation,dining}/

15. Knowledge-Based Analysis USE of KRG (specific or generic) ex) Beating an egg in a mixing bowl Kitchen job (preparation(beating)) using a kitchen item/shape(dished)/function{preparation}/ specific Kitchen job (preparation) using a kitchen item/shape(dished)/function{preparation}/ generic Kitchen job (preparation) using a kitchen /function{preparation}/ Useful for teaching purpose

16. Approaches to task analysis • Task decomposition - splitting task into (ordered) subtasks • Knowledge based techniques • - what the user knows about the taskand how it is organised • Entity/object based analysis • - relationships between objects, actions and the people who perform them

17. Entity-Relationship-Based Techniques Cataloging & Examination of objects and actions gardener soil spade dig It is the gardener who performs the digging acting upon the soil using the spade ObjectAttribute Action • Concrete objects : simple things: spade, plough, glasshouse • Actors : human actors - Vera, Sam, Tony, the customers • non human actor - irrigation computer • Composite objects : sets: the team = Vera, Sam, Tony • tuples: tractor may be < Fergie, plough >

18. Entity-Relationship-Based Techniques • ObjectAttribute Action • Object Pump3 simple – irrigation pump • Attributes: • status: on/off/faulty • capacity: 100 litres/minute Implicit Indirect Message Role ObjectAttribute Action • agent – who performs the actions • patient – which is changed by the action • instrument – used to perform action • examples: • Sam (agent) planted (action) the leeks (patient) • Tony dug the field with the spade (instrument)

19. Entity-Relationship-Based Techniques • Example Object Sam human actor Actions: S1: drive tractor S2: dig the carrots Object Vera human actor – the proprietor Actions: as worker V1: plant marrow seed V2: program irrigation controller Actions: as manager V3: tell Sam to dig the carrots Object the men composite Comprises: Sam, Tony • Object glasshouse simple • Attribute: • humidity: 0-100% • Object Irrigation Controllernon-human actor • Actions: • IC1: turn on Pump1 • IC2: turn on Pump2 • IC3: turn on Pump3 • Object Marrow simple • Actions: • M1: germinate • M2: grow Event : performance , spontaneous, timed

20. Entity-Relationship-Based Techniques • Relations • object-object • social - Sam is subordinate to Vera • spatial - pump 3 is in the glasshouse • action-object • agent (listed with object) • patient and instrument • actions and events • temporal and causal ‘Sam digs the carrots because Vera told him’ • temporal relations • use HTA or dialogue notations. • show task sequence • show object lifecycle

21. Entity-Relationship-Based Techniques • Application 0. inorder to grow marrows 1. Vera sows the marrow seed 2. marrow germinates 3. Vera programs controller 4. controller waters field 5. marrow grows 6. Sam hoes 7. Tony havests marrows Plan 0 : 1-2-5-when crop is mature 7 when rainfall is low 3-4 when weeds grow 6

22. Entity-Relationship-Based Techniques • Life Cycle 0.life cycle of tractor Plan 0. as require -2 When tractor break down -1 1. maintenance 2. cultivation Plan 2. 2.1-2.2-2.3-2.4-2.5 2.1 connect implement 2.2 drive to field 2.3 cultivate field 2.4 drive to tool shed 2.5 put away Plan 2. 1 one of 2.1.1 or 2.1.2 depending on job 2.1.1. fix harrow 2.1.2 fix plough

23. Source of information and data collection • Documentation • - Supposed & Functions • - Useful basic action & object • Observation - formal/informal, laboratory/field, Passive/Active • Interviews • Direct & Quick Way • Both Manager & Actual Worker

24. Source of information and data collection Extraction from transcripts • list nouns (objects) and verbs (actions) • beware technical language and context `the rain poured’ vs. `I poured the tea’ Sorting and classifying • grouping or arranging words on cards • ranking objects/actions for task relevance • use commercial outliner

25. Uses of Task Analysis Make pot of tea once water has boiled warm pot put tea leaves in pot pour in boiling water –– page 3 –– To make cups of tea boil water –– see page 2 empty pot make pot –– see page 3 wait 4 or 5 minutes pour tea –– see page 4 –– page 1 –– Conceptual Manual • from knowledge or entity–relations based analysis • good for open ended tasks Procedural ‘How to do it’ Manual • from HTA description • good for novices • assumes all tasks known Cookey in eight easy lesson Lec1. preparation – dished utensils Lec2. preparation – flat utensils Lec3. job for food preparation Lec4. cooking – dished utensils … Lec8. dining – graceful eating and drinking (followed by four course dinner)

26. Uses of Task Analysis Requirements capture and systems design • lifts focus from system to user • What should be in new system? • What novel features are to be? Detailed interface design • taxonomies suggest menu layout • object/action lists suggest interface objects • task frequency guides default choices • existing task sequences guide dialogue design Task analysis is never complete • Support the way people want to work