1. TASK ANALYSIS 공병돈

2. 2/26 TASK ANALYSIS 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. 3/26 TASK ANALYSIS 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. 4/26 TASK ANALYSIS Differences Between task analysis and other technics System AnalysisVSTask Analysis System designfocusThe user Cognitive modelVSTask analysis Internal mental stage focus Extenal action Practiced unit taskWhole job

5. 5/26 TASK ANALYSIS Approaches to task analysis Task decomposition - splitting task into (ordered) subtasks Knowledge based techniques - what the user knows about the task and how it is organised Entity/object based analysis - relationships between objects, actions and the peo ple who perform them

6. 6/26 TASK ANALYSIS 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. 7/26 TASK ANALYSIS Task Decomposition Stopping rule -> Depend on purpose of task analysis P*C rule Complex motor response or Internal Decision Making 0. in an emergency 1. read the alarm 2. work out appropriate corrective action 3. perform corrective action

8. 8/26 TASK ANALYSIS Task Decomposition Make Pot

9. 9/26 TASK ANALYSIS Task Decomposition fixed sequence optional tasks wait for events cycles time-sharing mixtures

10. 10/26 TASK ANALYSIS 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. 11/26 TASK ANALYSIS Approaches to task analysis Task decomposition - splitting task into (ordered) subtasks Knowledge based techniques - what the user knows about the task and how it is organised Entity/object based analysis - relationships between objects, actions and the people who perform them

12. 12/26 TASK ANALYSIS Knowledge-Based Analysis Listing all objects & actions -> Build texonomy Aim : Understand needed knowledge about task Help production teaching material Common knowledge between differ task 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 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!

13. 13/26 TASK ANALYSIS 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. 14/26 TASK ANALYSIS 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/function{preparation,dining}/ Kitchen item/shape(flat)/ Function {preparation,dining(for food)}/

15. 15/26 TASK ANALYSIS Knowledge-Based Analysis USE of KRG (specific or generic) ex) Beating an egg in a mixing bowl Kitchen job (preparation) using a kitchen item/shape(dished)/function{preparation}/ Kitchen job (preparation(beating)) using a kitchen item/shape(dished)/function{preparation}/ Kitchen job (preparation) using a kitchen /function{preparation}/ Useful for teaching purpose generic specific

16. 16/26 TASK ANALYSIS Approaches to task analysis Task decomposition - splitting task into (ordered) subtasks Knowledge based techniques - what the user knows about the task and how it is organised Entity/object based analysis - relationships between objects, actions and the peo ple who perform them

17. 17/26 TASK ANALYSIS Entity-Relationship-Based Techniques Cataloging & Examination of objects and actions gardenersoilspadedig It is the gardener who performs the digging acting upon the soil using the spade Object Attribute 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

18. 18/26 TASK ANALYSIS Entity-Relationship-Based Techniques Object Attribute Action Object Pump3 simple – irrigation pump Attributes: status: on/off/faulty capacity: 100 litres/minute 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) Object Attribute Action Implicit Indirect Message Role

19. 19/26 TASK ANALYSIS 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 Controller non-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. 20/26 TASK ANALYSIS 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. 21/26 TASK ANALYSIS Entity-Relationship-Based Techniques Application 0. in order 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. 22/26 TASK ANALYSIS Entity-Relationship-Based Techniques Life Cycle 0. life cycle of tractor 1. maintenance 2. cultivation 2.2 drive to field 2.3 cultivate field 2.4 drive to tool shed 2.5 put away2.1 connect implement 2.1.2 fix plough 2.1.1. fix harrow Plan 0. as require -2 When tractor break down -1 Plan 2. 2.1-2.2-2.3-2.4-2.5 Plan 2. 1 one of 2.1.1 or 2.1.2 depending on job

23. 23/26 TASK ANALYSIS 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. 24/26 TASK ANALYSIS 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 Source of information and data collection

25. 25/26 TASK ANALYSIS 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 Uses of Task Analysis 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 –– Make pot of tea warm pot put tea leaves in pot pour in boiling water –– page 3 –– once water has boiled 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. 26/26 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 Uses of Task Analysis