IE 210 – Exam 3

Lecture 17 – Operations & Task Analysis- Task analysis and cognitive task analysis is one of the most important tools

that can be used for understanding the user and how they perform their job- There is a difference between how protocols and procedures say work is

being done and how it is actually being done- Human Factors Engineering

o The goal: Make systems successful by enhancing performance,

satisfaction, and safety Part of this is through design by taking into account

How people think How people can perceive stimuli from the environment How people can respond (both based on cognitive and

physical limitations) User’s preferences

- Front End Analysiso Purpose is to understand the users, their needs, and the demands of

the work situation User analysis

Who are the regular users or “operators” of the product or system?

Environmental analysis Where will the product/system be used? Can be performed concurrently with user and task

analysis? Function analysis

Can the system perform the basis functions expected by the user?

- Task analysiso Systematic way to describe human interaction with the system to

understand how to match the demands of the system to human capabilities

o Critical component of user-centered design (know the user and what they need to do)

o Study of physical and/or cognitive activities required of a person or team to achieve a goal

o Process1. Define the purpose of analysis and type of data to be collected

(physical actions or cognitive)2. Collect task data – how?3. Summarize task data4. Analyze task data

o Matrix representation of task data

OFM Function/Sub-function

CognitiveAgent Tasks

Input Human InformationProcessingResources

Output Task &EnvironmentalDemand

Course Execution/Determine position

IDENTIFY

Acquisition

GPS AUTOMATIC Estimate of currentposition

Quality of GPSsignal

Course Execution/Record position

CODE

Handling

Estimate ofcurrentposition,Electronic chart

AUTOMATIC Position plotted onchart, annotated withthe current time

Precision of theelectronic chart

Course Execution/Monitor progress

TEST

Interpretation

Actual position Perception, workingmemory/ AUTO

Deviation betweenactual and plannedlocation, or reachinga waypoint.

Properconfiguration ofECDIS

Course Execution/Coordinate with VTSand Pilots

DECIDE/SELECT

Interpretation

Estimatedarrival at awaypoint

Long-term memory,Processing strategy

Decision to contactVessel TrackingService (VTS) orpilot

The number ofother competingactivities

IDENTIFY

Acquisition

Conversationwith (VTS) orpilot

Working memory,Perceptual sensitivity

VTSrecommendation

Quality of radiocontact,Languagebarriers

o Analyze task data Network analysis: examine information flow Workload analysis: examine difficulty of tasks Simulation and modeling: examine changes in inputs to the

outputs Safety analysis: examine likelihood of errors Scenario specification: define script for users

o Considerations Avoid designing for current tasks because they may simply

reflect a poor system Analysis of system requirements and constraints Go beyond current tasks

o Purpose of task analysis Predict system performance Specify interface design requirements Define procedures and manuals Identify training requirements Guide the overall conceptual design of the system

o Importance of Task Analysis Understand system better

How job is really being done Decision making, communication, problem solving Teamwork Technology facilitators and barriers

Ensure the system is safe (hazardous area, past incidents)

Ensure productivity through determination of when and where to automate

Ensure effectiveness of system

Lecture 18 – Time Studies- For the best results, from a productivity viewpoint, first, design the job using

HFE principles, then complete a time study- Time studies are used to find the most efficient (and hopefully safe) way to

complete a job- Work Measurement Studies

o Work measurement study is a general term used to describe the “systematic application of industrial engineering techniques to establish the work content and time it should take a complete a task or series of tasks”

o Work measurement involves the use of engineered labor standards to measure and control the amount of time required to perform a specific task or tasks

o Work measurement is a productivity improvement toolo Before improvements can be made, the current productivity level of

an organization must be measuredo This measurement is then used as a baseline to determine if

improvement projects have resulted in genuine improvemento Work measurement helps to uncover non-value added areas of waste,

inconsistency, and non-standardization that exist in the workplace. It uncovers ways to make work easier, and to produce products or services more quickly and economically

o Work is measured for 4 reasons1. To discover and eliminate lost or ineffective time2. To establish standard times for performance measurement3. To measure performance against realistic expectations4. To set operating goals and objectives

o While labor standards are most commonly associated with manufacturing or production environments, standards are used in many other types of settings including, but not limited to

Service (restaurant) or administrative Warehousing and distribution Retail Sanitation Janitorial Medical Utilities

o Work Measurement Techniques Time study Predetermined Time Systems* Standard Time Data (Standard Data)*

Work Sampling (Statistical sampling theory)*these methods need to consider allowances (planned deviations from the ideal)

o Work and Time After proper ergonomics and method have been designed we

can address how long tasks and activities takeo Why we do it

Uses of time per task/activity data Allocation of labor costs to total cost of

production/service Determining schedules and planning work Determining machine effectiveness Evaluation of alternatives Ergonomic job evaluations

o How we can do it Nonengineered (Type II) Standards – “did take” time

Historical records Ask an expert Work sampling

All of these Do not assess effort Do not verify proper method Can be very inaccurate (mostly subjective) Should be regarded as temporary and only be used for

limited time until engineered standards can be developed

o How we should do it Begin with thorough methods and quality analysis (Task

analysis) Insure that correct methods are known, documented,

and in use Insure that processes are stable

Communicate with workers involved Learn from them Gain their support, insure that advantages of correct

method and time estimates are known and understood Estimate the time or stop watch or video (Type I standards –

“should take” time) Document the standard Maintain the standard

- Steps in a time studyo Methods analysis

To insure safe and productive method is known and being used To leave permanent record of the method as a basis for future

comparisons

To develop elemental breakdown Make it possible to reuse the data Permit different ratings for different elements Permit consistency checks, within and between studies Improve method descriptions Can find omissions in long-cycle task

o Operator selection Select experienced, “average” workers Discuss the study, the method, and the objective of the

standardo Timing

Observe and record time taken by operator Check to ensure sufficient number of cycles have been

recordedo Rating

To establish the difference between observed work and “the pace of a motivated worker with sufficient skill and physical ability to do the job, working at a suitable pace that can be maintained through the shift and the day after day”

Proposed methods Pace rating: speed Objective rating: speed, difficulty/effort

- Elemental Breakdowno Data is readily reusable when each element is described separately,

especially beginning and ending points1. The elements should be as short in duration as can be

accurately timed (not in individual hand motions, which are too short in time)

2. Handling time should be separated from machine time3. Constant elements should be separated from variable elements4. Regular elements are recorded first, then all others

- Number of Observationso Two approaches to determining number of observations

Statistical Importance of Decision Rule of Thumb: Take at least 20 good readings for cycles of 2

minutes or less; take around 5 good readings for cycles greater than 2 minutes

- Things that go wrongo Missed readingso Missed elementso Elements out of ordero Foreign elementso Large number of missed or out-of-order elementso Watch stopped, batteries run down

o Machine or process failure, frequent external interruptions- Finishing the study

o Observed time: “raw” (unadjusted) time taken by workero Normal time: Time of experienced worker should takeo Standard time: normal time is increased to allow for allowances

Personal allowances: blowing nose, bathroom break, getting drink of water, smoking, coffee

Fatigue allowances: physical, mental, environmental climate, dust, dirt, noise, eye strain

Delay allowances: machine breakdowns, material flow interruption, conversations with supervisors

Special allowances: based on unique characteristics of the job

Lecture 19 – Predetermined Time Systems- Can accurately predict the amount of time for a task- However, there is an extensive evidence that the theory and reality don’t

agree- Right now, this is the best tool we have and it gets us “close enough” data- Predetermined Motion Time Systems

o Based on Gilbreth’s therbligso Refined by micromotion analysis and synthetic ratingo Assume that work elements are independent and additiveo Resulting standards are for a “typical motivated, trained and fit

worker” at 100% paceo Standards can be created at the desktop, based on information on the

method and workplaceo Major cautions:

Verify conditions, tooling and methods, to avoid missing something

Use the appropriate system according to the task, usually based on duration and repetition of the actitivy

- Therbligs: set of fundamental motions required for a worker to perform a manual operation or task

o Search, find, select, grasp, hold, position, assemble, etc. - Common Systems

o MTM (Methods Time Measurement)

MTM-1 most detailed, and can be used for any task MTM-2 less detailed, requiring more judgment by the analyst MTM-3 even less, and much quicker to apply MTM-V, MTM-C, MTM-M and many other systems

o MOST (Maynard Operation Sequence Technique) Basic MOST, for general use Mini-MOST, for highly repetitive tasks Maxi-MOST, for long-cycle, non-repetitive tasks Based on MTM data Reduced analysis time Times estimated from ranges of motions rather than precise

measurement or estimation Requires minimal paperwork Consistent, widely accepted Structure encourages methods improvement

o MTM-1 Procedure to analyze any manual operation or method into the

basic motions required to perform it Assigns each motion a pre-determined time standard

Nature of the motion Conditions under which it is made

Motions broken down into 10 categories Reach, move, turn, apply pressure, grasp, position,

release, disengage, body (leg-foot, horizontal, and vertical) motions, eye motions

- Movementso Move object to the other hand or against stop (Case A)o Move object to an approximate or indefinite location (Case B)o Move object to exact location (Case C)o The shorthand for a 4-inch case C move is M4C.

- The Sequence Modelo Three phaseso Get – ABGo Put – ABPo Return – Ao Letters in sequence model represent

A – action distance B – body motion G – gain control P – placement

- Sequence Indexingo Each parameter has an index that gives us a time o Index selected based on application ruleso Summed and multiplied by 10 gives us time in TMU

- Common Sequence Models

o General Move Manual movement of an object freely (unrestricted path)

through space Ex: pick up a book and place it on a shelf, grasp a washer and

put it onto a bolt Not a general move: turn a knob, pull a lever, close a book ABG ABP A

o Controlled Move Manual displacement of an object over a controlled path Restricted in at least one direction by contact with or

attachment to another object, or the nature of the work requires deliberate move along a specific path

Ex: pull a lever, push a bottom, slide a box, turn a knob, flip a switch, open a door, fold a cloth, move a cup

Not controlled move: rest foot on foot pedal, put key in lock Get an object, move or actuate it and return Controlled or restricted path ABG MXI A

o Tool Use Combines General and controlled move in typical use of tools Two kinds of tool use

Fasten/Loosen, cut, surface treat, measure, record and think

Ex: attach a nut on a bolt with 5 finger spins, faster a screw with a screwdriver using 8 writ turns, cut open a box with a knife, read 3 words from a purchase order, wipe a surface with a cloth

Get a tool, place it for use, put aside, return ABG ABP F ABP A

- MOST Analysiso Break the task down into steps involving movement of an object

Freely through space – general move Over a restricted path – controlled move Using a tool – tool use Apply the appropriate time values for each parameter Total the time for the sub-operation (may involve several

sequences)- Applying MOST

o Paper and Pencil Write out sequence, select parameter index values Use MOST Analysis Form for multiple sequences in a task

o MOST for Windows Supports BasicMOST, MiniMOST, MaxiMOST Stores Sub-operations in database, prints reports Direct MOST

Lecture 20 – Designing Workplaces for Individuals with Disabilities- Universal design principles are flexible enough to create a product that can

be used by people with no limitations to people with varying limitations- Approaches to disabilities

o Change the individual Surgery, education, skill development, compensation strategies

o Provide the individual with tools Prosthetics and orthotics or assistive technologies

o Change the way that the world is designed Use universal design approaches

- Major Disability Groupso Visual Impairments

Low vision: Problems (after correction) such as dimness of vision, haziness, film over the eye, foggy vision

Blind: May still retain some perception of shape and contrast or of light vs. dark, or they may be totally blind

o Hearing Impairments Hearing Impaired: Any degree and type of auditory disorder Deaf: An extreme inability to discriminate conversational

speech through the ear Causes

Sensorineural Hearing Loss: Damage to the auditory pathways within the central nervous system

Conductive Hearing Loss: Damage to the outer or middle ear

o Physical Impairments (PI) Function Limitations Caused by PI

Poor muscle control, weakness and fatigue Difficulty walking, talking, seeing, speaking, sensing or

grasping (due to pain or weakness) Difficulty reaching things Difficulty doing complex or compound manipulations

(push and turn) Nature and Causes of PI

Neuromuscular Impairments: Paralysis, weakness, and interference with control, via spasticity

Skeletal Impairments: Joint movement limitations (either mechanical or due to pain), and small limbs, missing limbs, or abnormal trunk size

o Cognitive/Language Impairments Categorized as memory, perception, problem-solving, or

conceptualizing disabilities Types and Causes of C/L I

Mental Retardation: A person is considered mentally retarded if they have an IQ below 70 (average IQ is 100) and if they have difficulty functioning independently

Language and Learning Disabilities Age-Related Disease

o Seizure Disorders A seizure consists of an explosive discharge of nervous tissue,

which ofen starts in one area of the brain and spreads through the circuits of the brain like an electrical storm

A number of injuries or conditions can result in seizure disorders

Epilepsy is a chronic neurological disorder- ADA (American’s with Disabilities Act)

o Government mandate that guarantees equal access to employment, public accommodations, transportation, government operations, and telecommunications services

o An individual with a disability is any individual with a physical or mental impairment that substantially limits one or more major life activities.

o Qualified individual with a disability must be one who satisfies the requisite skill, experience, education, and other job-related requirements of the employment position that the individual holds or desires, and who with or without reasonable accommodation, can perform the essential function of such position.

- What topics does the ADA apply to?o Permanent disabilities (non-correctable)o Prohibits discrimination against people with disabilities in the

following areas Title I – employment Title II – public services (public transportation) Title III – public accommodations (below) Title IV – telecommunications Title V – miscellaneous (threatening or retaliating against the

disabled)- What are the public accommodations?

o Places that are generally open to everyone, such as restaurants, hotels, theatres, doctors’ offices, stores, museums, libraries, etc.

o Requires the removal of barriers when it is “readily achievable” to do so. This means that it must be fairly easy to do without much trouble or expense. Ex: making a simple ramp over a few steps.

o Private clubs and religious organization are not required to meet the ADA’s requirement for public accommodations

- Does the ADA apply to all employers?o For companies with 15 or more employees

o Job discrimination against people with disabilities by these employers is not legal if practiced by private employers, state and local governments, employment agencies, labor organization, labor management committees

o Does not apply to Federal Employees- What is a reasonable accommodation?

o How an employer adapts so that a disabled person can worko Any change or adjustment to a job that lets an employee with a

disability perform the essential functions of that jobo A change in procedure that allows a qualified person to apply for a jobo A change that allows a disabled person to enjoy benefits and

privileges of employment the same as those enjoyed by employees without disabilities

o Providing equipment or devices, or adapting them so the person with a disability can use them

- What are the “essential functions” of a job?o The fundamental duties required by the job itself.o Employers cannot refuse to hire you because your disability prevents

you from performing duties that are not essential to the job.o Employee must be a qualified individual with a disability. o Employers are not required to lower their job standards to

accommodate someone with a disability.o Employers do not have to provide personal-use items such as glasses

or hearing aids.- Universal design

o Designing products or environments that can be efficiently and effectively used by people with a wide range of abilities in a wide range of situations

o Why would we want to use universal design principles? Benefits everyone, not just people with disabilities New insights into the design Lower cost design

- Considerations for Product Designo Users need to be able to perceive all information presented by the

producto Users need to be able to operate the producto Users need to be able to understando Users need to be able to use their assistive technologies with the

product

Lecture 21 Contemporary Issues in Ergonomics – Aging- Aging is more than just getting older- Understand that with aging comes invaluable experience, but also limitations

in physical and cognitive abilities.

- If you design the workforce to support the aging workforce, it will be better for everyone.

- Video games and older peopleo Goal of a video game: allow the user to spend time immersed in an

experience Requires that the user makes errors as part of learning process Providing difficulties that challenge the players and prevents

fast successo Video games have been used to improve variety of outcomes

Physical therapy, educational learning, medical adherence, pain management, cognitive enhancements

o If an interface is difficult to use, younger users may have experience and technical abilities to compensate for the poor design, older users may not be able to use it.

o Older drivers may have difficulty because of perceptual, motor, cognitive changes

- Video game studyo Nintendo Wiio 56 participants over 65 years oldo Pre-test: demographic and health informationo Participants played game for 15 (1hr) sessionso Sessions were supervised by researcher and video tapedo Post-test: survey (experience playing the game), open ended

questions (overall difficulty & input device difficulty)o Based on the study results several design recommendations

Consider the physical limitations of older users (reduce motor dexterity, hand stiffness, trembling)

Adjust difficulty based on performance to minimize frustration and increase motivation

Conduct a cognitive task analysis to identify tasks within a game that may be particularly challenging for older players

- An aging workforceo Aging workforce is a trend that organizations across all industries

must addresso Average age of the American worker increased from 34 years in 1984

to 39 years in 2000o As of 2007, the average age is 48 years oldo Baby boom generation now makes up 48% of the workforceo It is expected that the working population over the age of 55 will grow

by 38% in the next decade, and 75% in the next 25 years.- Common problems/effects related to aging include

o Muscle mass loss resulting in reduced strengtho Arthritis, a source of pain and loss of strengtho Decreased visual and auditory abilities

o Diminished nervous system response and reduced tactile feedbacko Decreased water content of tendons, cartilage, and connective tissues

causing stiffness, reduced cushioning, reduced elasticity and flexibility, and increased susceptibility to stresses

o Loss of strength, loss of flexibility, loss of range of motion, etc.- Why hire/retain older employees?

o Older workers tend to be more prompt, productive and have less absenteeism than younger workers

o Often older workers have more flexible scheduleso Wisdom, experience, expertiseo Avoid cost of employee turnovero Possible future labor shortage (as baby boomers retire)o Remain competitive in the market

- What can employers do to accommodate the aging workforce?o Redesign workstations (lighting, angle of computer)o Re-evaluate manual material handling tasks/supporto Educate employees regarding their limitation and capabilitieso Identify the jobs that are creating the most risk factors for all age

groups.o Re-engineer tasks with the highest risk factorso Provide administrative alternatives when reengineering is not

feasible

Lecture 22 – Error Reduction and Safety- How do accidents happen?

o Components in the system or in interaction create hazardso Human error

- Who has the responsibility to control hazards?o Engineering Departments

Design facilities to be free of uncontrolled hazards Provide technical hazard information Explain how and help to follow technical standards

o Manufacturing Design better tools and equipment Develop safer, more efficient methods

o Quality Control Test and inspect all materials (raw and processed) Research and suggest alternative materials

o Purchasing Ensure that materials and equipment meet standards Disseminate info obtained from manufacturer Purchase well designed equipment and tools

o Maintenance Perform continuous preventive maintenance

Ensure proper installation of all equipmento IE

Establish workable safety program and continue to monitor- Error: Those occasions in which a planned sequence of mental or physical

activities fails to achieve its intended outcome, and when those failures cannot be attributed to chance.

o Slips and lapses are errors that result from some failure in the execution and/or storage stage of an action sequence, regardless of whether or not the plan that guided them was adequate to achieve its objective.

o Mistakes are deficiencies or failures in judgmental and/or inferential processes involved in the selection of an objective or in the specification of the means to achieve it.

- How do errors happen?o Latent errors (built into the system) pose the greatest threat to safety

in a complex system and give rise to..o Active errors: Human errors at the point of operationo Many safety programs mistakenly focus and fixate on the active errors

- System (latent) factorso Managemento Physical Environmento Equipment designo Work or jobo Social/psychological environmento Worker/coworker

- What do you do about errors?o Eliminate, avoid or prevent errors through improved system designo Facilitate recovery from errors that do happen by making errors

visible and with recovery features (undo)o Facilitate learning from errors to reduce the likelihood of similar

future errors (Send error report?)- Occupational Safety and Health Act

o Enforces mandatory job safety & health standards- General duty clause of OSHA Act

o Each employer Shall furnish to each of his employees employment and a place

of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees

Shall comply with occupational safety and health standards promulgated under this Act

o Each employee

Shall comply with occupational safety and health standards and all rules, regulations, and orders issued pursuant to this Act which are applicable to his own actions and conduct

- Who is covered?o All organizations, even if they only have 1 employee. No small

business exemptiono Organizations with 10 or fewer employees are exempt from

inspections and record keeping requirements as are some industries but they must report in a fatality or the hospitalization of three or more employees

- Effective Safety Program Elementso Management leadership and employee participationo Hazard identification and assessmento Hazard prevention and controlo Information and trainingo Evaluation of program effectivenesso Medical management

- What are safety analyses?o The proactive analysis of new systems, new machines, new

environments, new plants, new plans, new operations for hazardso The proactive analysis of existing systems, machines, environments,

plants, plans and operations for hazardso Reactive analyses that determine causes of unwanted outcomes such

as errors, violations, injuries and accidents- What is the purpose of these analytical methods?

o Identify hazardso Determine causeso Determine possible effectso Preventiono They all help with “sensemaking” or helping organizations make sense

of their situation- Prevent access

o Isolation Isolating chemicals, that in combination could cause a toxic

product Isolate employee from hazard (can only interact with a

dangerous product, such as a virus, through protection screens with gloves)

Isolate hazard – machine guardso Lockout: Prevents an event from occurring or prevents person/object

from entering an undesired zoneo Lockin: Keeps person/object from leaving restricted zoneo Interlocks

A cannot occur

Until B also happens – intentional action While condition C exits

In other words, proper sequence of actions are necessary for proper operation