Issues Related to Design of Automatic Systems - from a Human Factors Perspective -

Issues Related to Design of Automatic Systems

- from a Human Factors Perspective -

Ann Britt SkjerveInstitute for Energy Technology

Human-Centered Automation

Content

Part I: Overview• Background and definition

• The operators’ role

• Keys Research Issues1. Task allocation

2. Human-system interface design

3. Effects on the individual and

the organisation

Part II: Two examples on interface design studies• Human-Centred Automation Experiments

• Extended Teamwork Study

Domain: High-risk systems.

Background

• 1952: The term automation was applied in an article in Scientific American

• Mechanization of human labour – Overcome human capacity problems– Automation of “physical” tasks – Routine tasks Production increase

• Complex and safety critical tasks– Automation of “control” tasks (Crossman,

1974)

– Automation of “management” tasks (Billings, 1991)

Definition(s)

Oxford English Dictionary:

• Automatic control of the manufacture of a product through a number of successive stages;

• The application of automatic control to any branch of industry or science;

• By extension, the use of electronic or mechanical devices to replace human labor.

automation

Why are Humans still in High-Risk Systems?

• Not all tasks can be

automated...

– Degree of proceduralization

– Automation may fail

– Technology

• Cost effectiveness

• Legal requirements

• Public opinion

1 2 3 41 2 3 41 2 3 4

1 23?

43?

1 23?

43?

1 23?

43?

Classification Systems: Ten Levels of Automation – an example (Sheridan, 1980)

1. Human considers alternatives, makes and implements decision.2. Computer offers a set of alternatives which human may ignore in

making decision.3. Computer offers a restricted set of alternatives, and human decides

which to implement.4. Computer offers a restricted set of alternatives and suggests one,

but human still makes and implements final decision.5. Computer offers a restricted set of alternatives and suggests one,

which it will implement if the human approves.6. Computer makes decision, but gives human option to veto before

implementation.7. Computer makes and implements decision, but must inform human

after the fact.8. Computer makes and implements decision, and informs human only

if asked to.9. Computer makes and implements decision, and informs human only

if it feels this is warranted.10. Computer makes and implements decision if it feels it should, and

informs human only if it feels this is warranted.

Degre

e o

f co

mpute

r part

icip

ati

on

LOW

HIGH

Effects of Automation 1/2

Some positive effects– Increased production levels

• Automatic train control (ATC)• Trains: Faster and with shorter distances

between• Each new generation of commercial aircrafts

has improved on the safety record of its predecessors

– Automation as a “key” element of competitiveness”

Aircraft Generations

1st generationB707DC8

3rd generationMD80 A300-600/ A310MD11 A319/A320/A321MD90 A330/A340B737-300/400/500B757/B767 B777

2nd generationB727B737-100/200B747DC9DC10A300B4

012

34567

89

10

1959

1961

1963

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1st generation

2nd generation3rd generation

All aircraft

Hu

ll lo

ss /

mill

ion

dep

art

ure

s

Accident rate for 3 generations of aircrafts (Airbus Industry Safety Department “Hangar Flying”, June 1997, as referred in Pariès and Amalberti, 1999).

Effects of Automation 2/2

Some negative effects associated with automation use– Increased complexity

for the human operator:

– Reduced safety margins

– Operators are left to deal with automation malfunctions

– Reduced possibility for practising operational skills

In case of a malfunction indication:1. Does the alarm reflect a dangerous situation?2. Is the automated monitor failing?3. Is the display indicator failing?

AUTOmonitor

Alarm

Display

In case of a malfunction indication:1. Does the alarm reflect a dangerous situation?2. Is the automated monitor failing?3. Is the display indicator failing?

AUTOmonitor

Alarm

Display

Key Research Issues - From a HF Perspective

1. Task allocation– How should tasks be allocated between humans and

machine?

2. Design of the human-system interface– How should the human-system interface be designed to

support the operators’ performance?

3. Effects on the individual and the

organisation– How is the individual and the organisation

affected by automation?

Task Allocation

How should tasks be allocated between humans and machine?

Three strategies for task allocation• The Left-Over Principle• The Comparison Principle• The Complementary Principle

The Left-Over Principle 1/2

• Operators are the most unreliable element• To the extent possible operators should be eliminated

from the production process• Automate everything that can be automated• The tasks that cannot be automated (i.e., fully

proceduralised) are left-over to the operators.

“To improve the reliability of NPP’s, it is primarily effective to automate the hardware as much as possible and to eliminate to the maximum extent human intervention by recognition, judgement and response to information.” (Inoue et al., 1991, 449)

Example:

The Left-Over Principle 2/2

Critique– Tasks are left-over to the operators without

considering human capacity issues• Vigilance• Work load• Cognitive requirements

”... the designer who tries to eliminate the operator still leaves the operator to do the tasks which the designer cannot think how to automate.” (Bainbridge, 1993)

The Comparison Principle 1/2

• Human operators and automatic systems have different capabilities

• Allocate the tasks to the ’agent’ that is better suited to perform the task

What Men Can Do

Better Than Machines

What Machines Can Do

Better Than Men

Ability to detect small amounts of visual or acoustic energy (absolute sensory thresholds).

Ability to respond quickly to control signals, and to apply great force smoothly and precisely.

Ability to perceive patterns (stimulus generalisation).

Ability to perform repetitive routine tasks.

Ability to improvise and to be flexible.

Ability to store information briefly and then erase it completely.

Ability to exercise judgement. Ability to store very large amounts of information for long periods of time and recall relevant facts at the appropriate time and to generalise the knowledge obtained.

Ability to reason deductively including computational ability.

Ability to reason inductively.

Ability to handle highly complex operations, e.g. do many different things at the time.

Fitts’ List (1951)

The Comparison Principle 2/2

Critique

– Tasks are allocated without consideration for

the overall tasks performance process of the

human operators

– The overall operator tasks may not

correspond to human capacity

• Etc.

The Complementary Principle 1/2

• CRITIQUE OF THE LEFT-OVER AND THE COMPARISON PRINCIPLES: Considerations are given for how the different task elements should be allocated, not for how the human and the automatic system should perform the task together.

• Optimal task allocation is achieved by ensuring that the performance of the operators and the automatic system complement each other– How will the automatic system and the human

operators most efficiently perform the operational task?

The Complementary Principle 2/2

Critique

– Task performance is a dynamic process• It can be difficult to foresee in advance how a task

performance process will progress, and thus how humans and automation may most efficiently complement each other

– The limits of technology vs. the apparent adaptability of humans.

Design of the human-system interface

How should the human-system interface be designed to support the operators’ performance?

Changed operator role:– From primarily involving operation to primarily involving supervision and deviation handling.

Human-System Interface Design Issues 1/2

Difficulties associated with human-automation interaction:

– Monitoring load

– Vigilance

– Workload distribution

– Silent automation

– ‘Automation surprises’

“After three decades of highly prolific research on human vigilance, we are still making the same seemingly contradictory statement: a human being is a poor monitor, but that is what he or she ought to be doing.” (Wickens, 1992)

Human-System Interface Design Issues 2/2

• Representation of the systems activity, current problems:– Physical and mental Isolation (Norman, 1990)

• Isolated from the moment-to-moment activity

– Workload distribution: Too high or too low workload

– Increased complexity: Understanding what happens in situations with deviations

– ”Out-of-the-loop”

• Technical design, current issues in terms of Human Factors:– Compensatory activity, may hide deviations to the operators

– Reduced time-span to handle deviations

Human-Centred Design

Human-Centred Design (Rouse, 1991)

• Three central attributes:– It focuses on the roles of humans in complex systems

– Design objectives are elaborated in terms of humans’ roles

– Specific design issues that follow from these objectives

• Three primary objectives:– To enhance human abilities.

– To help overcome human limitations.

– To foster user acceptance.

• Example, approach: “...the purpose of a pilot is not to fly the airplane that takes people from A to B – instead, the purpose of the airplane is to support the pilot who is responsible for taking people from A to B.” (Rouse, 1991)

Human-Centred Automation 1/2

• Human-Centred Automation (HCA):

• Definition: Automation designed to work cooperatively with the human operators in the pursuit of stated objectives.” (Billings, 1991)

• Assumption: The human operator should always constitute the starting point in a design process, because the operator ultimately is responsible for the performance outcome

Human-Centred Automation 2/2

The HCA design principles:

The human operator must be in command:1) To command effectively, the human operator must be

involved.2) To be involved, the human operator must be informed.3) The human operator must be able to monitor the

automated systems.4) Automated systems must be predictable.5) The automated systems must also be able to monitor

the human operator6) Each element of the system must have knowledge of

the others’ intent.(Billings, 1991, 1997)

The gap between user-centred intentions and technology-centred development

Some causes:• Oversimplify the pressure and task demands from the users’

perspective• Assume that people can and will call to mind all relevant knowledge• Are overconfident that they have taken into account all meaningful

circumstances and scenarios• Assume that machines never err• Make assumptions about how technology impacts on human

performance without checking for empirical support or despite contrary evidence

• Define design decisions in terms of what it takes to get the technology to work

• Sacrifice user-oriented aspects first when tradeoffs arise• Focus on building the system first, then trying to integrate the results

with users.

(Sarter, Woods and Billings, 1997)

Effects on the individual and the organisation

• How is the individual and the organisation affected by automation?

Changed operator role:– New design New ways of working…

Individual Skills

Individual Skills

• Manual control skills

– Gradual decay

• Cognitive skills

– Frequency of use, retrieval

– Reduced feedback, memory

Vigilance 30 minutes

Organizational Issues

• Changes in work content• Changes in work practices

– Changes in the lines of authority– Changes in the responsibility of staff members

• Changes related to status (-> self-esteem)

MotivationJob satisfaction

Safety

Education and Training Possibility for intervening Willingness to intervene

Will the system in practicefulfil the goals it wasdesigned to fulfil?

TWO EXAMPLES Focusing on Interface Design

Part II

Interface Design

– Starting point: Task allocation has

been decided (see ISO model)

– Question: How should the human-

system interface be designed to

support human-automation

transaction?

Two Research Programs

– Human-Centred Automation

– Extended Teamwork

Phase A

Phase C

Phase E

Phase B

Phase D

Step 7: Design Conceptual Framework

Step 2: Analyse Functions

Step 1: Clarify Goals and Requirements

Step 0: HF Programme Management

Step 3: Function Allocation

Step 4: Analyse Tasks

Step 5: Analyse Job and Work Organisation

Does

the design meet

requirements?

Step 9: Detailed Design and Build

Control

room

layout

Step 11: Operational Feedback

Displays

and

control

design

Environ-

ment

Work-

station

layout

Operational

and

management

requirements

Training ProceduresControl

suite

layout

Does

the design meet

requirements?

Set performance parameters

Compare with performance

parameters. Does the control

room work as intended ?

yes

no

yes

Step 6: V & V Phase B

Step 8: Approve Conceptual Design no

Step 10: V & V of Detailed Design

Modifications/upgrades: changes in function

analysed, collect data on existing

functions/constraints

New designs: all

functions analysed

no

Control Centre Design and Modification Process, (based on ISO Std. 11064-1, 2000).

IFEs Human-Centered Automation (HCA)

Research Program

Motivation: Providing a better understanding of how operators’ performance is influenced by automation to reduce the negative effects of automation.

Main Issues: To develop theories on how automation may influence operator performance, based on experimental studies. To develop measures for studying human-automation interaction.

Specific Goal: Develop HCA design support.

Introduction to the HCA Program, cont.

Research question: How do operators handle two types of

automation malfunctions when operating from human-machine interfaces, which contain either explicit or implicit

information about the activities of the automatic system?

Automation: Defined as: Interlocks, limitations, protections, controllers, programs

Independentvariables: (1) Automation Malfunction Type

(2) Automation-Information Presentation Type

The HCA-2000/2001 Experiments

Design of Human-System Interface

Basic Representation Types

• Implicit: Representation of a device’s activity through its

effect on something else

• Explicit: Direct representation of a device’s activity

Basic Representation Forms (include)

• Text

• Graphic

• Sound

• Etc.

Automation-Information Presentation

How may the activity of the

automatic system be represented

explicitly ?

– Explicit presentation of main activities

– Graphic feedback

– Verbal semantically meaningful feedback

– Intentional agent

Conventional Interface

• Main process components

• Main process flow

• Control formats

Experimental Interface

+ Main automatic devices

+ Computerized logic diagrams

+ Verbal feedback

Two Automation-Information Presentation Types

Program ’A3’ is starting up

The Conventional Interface

The Experimental Interface

• Study performed in HAMMLAB (NORS)

• Licensed operators from the Loviisa NPP

• Six crews of three operators (RO/TO/SS)

• Four scenarios - a basic scenario combined with two sets of automation malfunctions

• Two experimental manipulations

• Two breaks in each scenario

Overview of the HCA-2001 Experiment

System-Performance Measures– Operator Response Time (ORT) – OPAS MF, intervening actions (ACT)

Human-Performance Measures– OPAS MF, detection (DET) – Situation Awareness Rating Technique – Halden Complexity Questionnaire – Halden Cooperation Quality Questionnaire– Halden Trust in Automation Questionnaire

Measurement Techniques

Main Characteristics• 2x2(x3) within-subject design • Counterbalancing of the presentation order and the combination of the experimental conditions across crews • Psychometric evaluation of response data before hypothesis testing [construct validity, inter-item reliability, criterion validity].

• ANOVA for statistical hypothesis testing.• Hypothesis test performed at the crew-scenario level.

Changes Introduced:• Malfunctions re-sat after each scenario period (20 min). • Basis scenario: One turbine synchronised.• Inclusion of a shift supervisor.

Experimental Design

The Effects of the Interface Manipulation

Workload

Interpretation

The beneficial effects of the experimental AIP

interface are significant.• HCA-2000 and HCA-2001• Detailed information about the automatic

system’s activity• Graphically• Verbal feedback

• Complexity <> the number of items represented !

The Extended Teamwork 2004/2005 Exploratory Study

- Focusing on Human-Automation Co-operation

Main programPart programCondition for executionList of sequences

Have performed Currently PerformsWill be performed

Selection of agent

Latest voice message

Action suggestion



Selection of agent


Action suggestion





Selection of agent


Action suggestion

Background: Upcoming Industry Needs

New operational concepts are currently being debated in thedomain of nuclear power plants:

multiunit operations by a single operator

remote unit operations by a single crew

no full-time, on-duty operations staff, occasional operations tasks are performed by other functional units (e.g., engineering or maintenance)

reduced staff with an individual for multiple reactors and decentralized functional groups for maintenance and emergency

Etc.

A substantial increasein the automation level

Changed staff rolesStaff reduction?

New requirementsassociated withoperation

New tools NPPprocess

Increased levels ofautonomy and authority

Research Question

HomePlant

Pre- Experimental Control-Room Solution

HomePlant

Training Exploratory Study

Firstscenario

Lastscenario

Field visits

Background for understandingthe point of transition

Period with increasedfamiliarization

The purpose of the Extended Teamwork Research Program: To contribute with knowledge on how new operational concepts may affect the quality of teamwork in an operational team.

The purpose of the Extended Teamwork Study: To assess how familiarity with operation in a subset of a particular (see prev. slide) new operational environment may affect teamwork.

Teamwork - Theory

Taskwork and TeamworkTaskwork and Teamwork

Co-operation Theory or

Social-Interdependence

Theory…how people believe their goals to

be related to the goals of other

people is a useful way to

understand dynamics of the

interaction between humans and its

consequences…

Attributes of teamwork• share information openly• take one another’s perspective• communicate and influence each other• exchange resources• assist and support one another• handle conflicts efficiently

Types of Teamwork

NPPprocess

NPPprocess

Types of teamwork considered:

– Teamwork between humans• Co-operation Across Distances

– “Teamwork” between humans

and automation • Human-Centred Automation

– Extended teamwork• Teamwork-knowledge

framework

Extended teamwork: a distinguishable set, at a minimum, two human agents and a machine agent who interact dynamically, interdependently and adaptively toward a common goal.

Main Characteristics of the Study

Preliminary

Experimental Facilities: HAMMLAB and the VR-lab

Participants: 6 crews of licensed NPP

operators, Swedish NPPs crew: – Reactor operator (RO) – Shift-supervisor (SS)– Field operator (FO)

Scenarios• 12 scenarios, 40 minutes, minor disturbances, requiring co-operation• The presentation order of the scenarios was randomised.

Real Role Exp. Role Assumed location (Lab)RO or SS Control Room Operator Remote Control-Center

(HAMMLAB)RO or SS Site Co-ordinator On-site (VR-Lab)FO Technician On-site (VR Lab)

Experimental Team-Composition:

HAMMLAB VR-LAB

Control-RoomOperator

Co-ordinator

Technician

Location of the 3 crew members

HAMMLAB VR-LAB


Co-ordinator

Technician


Key Measures: Human-Automation

• Interviews– Following training and following

completion of the 12 scenarios.– Expectations and lessons learned

• Human-Automation Co-operation Quality

• Trust in Automation– Questionnaires – Operators’ subjective judgements

• Teamwork quality– Process expert’s rating of teamwork

• Operators’ ability to detect critical events– Operators ability to detect

predefined critical events.

The Control-Room Operator at Work

HAMMLAB VR-LAB


Co-ordinator

Technician


HAMMLAB VR-LAB


Co-ordinator

Technician


The Automatic Agents

Main programPart programCondition for executionList of sequences Have performed Currently Performs Will be performed

Selection of agent


Action suggestion

Results: Familiarization

Teamw ork-R elated Measures(C rew-leve l)

1 2 3 4 5 6 7 8 9 10 11 12

Run Number

-1,50

-1,25

-1,00

-0,75

-0,50

-0,25

0,00

0,25

0,50

0,75

1,00

Human-Auto Co-op.

Collective Efficacy

Trust in Auto

TeamBars (expert)

Human-Human Co-op.

Results: Human-Agent Co-operation

Interviews• CROs view on the Agents

– Initially a rather negative view on the Agents: (1) Usefulness and (2) Co-operability.– After the 12 scenarios, a much more positive view: (1) Necessary, (2) Co-operative, but (3) Context sensitivity should be increased.

• In general, the CROs feel lonely– Misses support, in particular in situations with deviations.

Human-Agent Transactions

• The level of Agent use is scenario dependent.– Total Freeze Time demonstrated a significant correlation with the operators’

subjective judgment of human-automation co-operation quality.

• The higher the level of human-agent transaction, the better the operator

is able to detect critical occurrences.

A Control-Room Operator (CRO)at work.

Implications: Design of Automatic Agents

• When designing Automatic Agents, the following would be useful:

• Application of verbal feedback .– A similar result was obtained in

the “Human-Centred Automation” experiments.

• “Action suggestions” function – Is particularly useful in

situations that the operators do not encounter often.

• “Freeze” function– Is a must for the operators’ to

remain in control.• “Repeat message” function

– Is a must when verbal feedback is applied.



Selection of agent


Action suggestion



Selection of agent


Action suggestion





Selection of agent


Action suggestion

The operators’ need of the Agents seems to facilitate their acceptance of the Agents.

The Human-Agent Interface.

In addition from the HCA experiments: Complexity is not determined by the number of items represented at the interface…

Summary of the Main Issues

Three task allocation principles– Left-Over– Comparison– Complementary

Human-System Interface Design– Silent interfaces– Representation, feedback– Human-Centred designs– Human-Centred Automation

Effects on the individual and the organisation– Deskilling– Organisational changes – Affect how and the extent to which a system will be used.

Examples:– IFEs Human-Centred Automation Program– IFEs Extended Teamwork Program - Teamwork where automatic

agents are team members?

Issues Related to Design of Automatic Systems - from a Human Factors Perspective -

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