ヒューマンファクターと人間工学 (Human factors and ergonomics)

字幕表動画を再生する

Human factors and ergonomics Human factors and ergonomics is a multidisciplinary
field incorporating contributions from psychology, engineering, biomechanics, mechanobiology,
industrial design, physiology and anthropometry. In essence it is the study of designing equipment
and devices that fit the human body and its cognitive abilities. The two terms "human
factors" and "ergonomics" are essentially synonymous.
The International Ergonomics Association defines ergonomics or human factors as follows:
HF&E is employed to fulfill the goals of occupational health and safety and productivity. It is
relevant in the design of such things as safe furniture and easy-to-use interfaces to machines
and equipment. Proper ergonomic design is necessary to prevent repetitive strain injuries
and other musculoskeletal disorders, which can develop over time and can lead to long-term
disability. Human factors and ergonomics is concerned
with the "fit" between the user, equipment and their environments. It takes account of
the user's capabilities and limitations in seeking to ensure that tasks, functions, information
and the environment suit each user. To assess the fit between a person and the
used technology, human factors specialists or ergonomists consider the job (activity)
being done and the demands on the user; the equipment used (its size, shape, and how appropriate
it is for the task), and the information used (how it is presented, accessed, and changed).
Ergonomics draws on many disciplines in its study of humans and their environments, including
anthropometry, biomechanics, mechanical engineering, industrial engineering, industrial design,
information design, kinesiology, physiology, cognitive psychology and industrial and organizational
psychology. Etymology
The term ergonomics, from Greek ἔργον, meaning "work", and νόμος, meaning "natural
laws" first entered the modern lexicon when Polish scientist Wojciech Jastrzębowski used
the word in his 1857 article Rys ergonomji czyli nauki o pracy, opartej na prawdach poczerpniętych
z Nauki Przyrody (The Outline of Ergonomics; i.e. Science of Work, Based on the Truths
Taken from the Natural Science). The introduction of the term to the English lexicon is widely
attributed to British psychologist Hywel Murrell, at the 1949 meeting at the UK's Admiralty,
which led to the foundation of The Ergonomics Society. He used it to encompass the studies
in which he had been engaged during and after World War II.
The expression human factors is a North American term which has been adopted to emphasise the
application of the same methods to non work-related situations. A "human factor" is a physical
or cognitive property of an individual or social behavior specific to humans that may
influence the functioning of technological systems. The terms "human factors" and "ergonomics"
are essentially synonymous. Domains of specialization
Ergonomics comprise three main fields of research: Physical, cognitive and organisational ergonomics.
There are many specializations within these broad categories. Specialisations in the field
of physical ergonomics may include visual ergonomics. Specialisations within the field
of cognitive ergonomics may include usability, human–computer interaction, and user experience
engineering. Some specialisations may cut across these
domains: Environmental ergonomics is concerned with human interaction with the environment
as characterized by climate, temperature, pressure, vibration, light. The emerging field
of human factors in highway safety uses human factor principles to understand the actions
and capabilities of road users - car and truck drivers, pedestrians, bicyclists, etc. - and
use this knowledge to design roads and streets to reduce traffic collisions. Driver error
is listed as a contributing factor in 44% of fatal collisions in the United States,
so a topic of particular interest is how road users gather and process information about
the road and its environment, and how to assist them to make the appropriate decision.
New terms are being generated all the time. For instance, “user trial engineer” may
refer to a human factors professional who specialises in user trials. Although the names
change, human factors professionals apply an understanding of human factors to the design
of equipment, systems and working methods in order to improve comfort, health, safety,
and productivity. According to the International Ergonomics
Association within the discipline of ergonomics there exist domains of specialization:
Physical ergonomics Physical ergonomics is concerned with human
anatomy, and some of the anthropometric, physiological and bio mechanical characteristics as they
relate to physical activity. Physical ergonomic principles have been widely used in the design
of both consumer and industrial products. Past examples include screwdriver handles
made with serrations to improve finger grip, and use of soft thermoplastic elastomers to
increase friction between the skin of the hand and the handle surface. Physical ergonomics
is important in the medical field, particularly to those diagnosed with physiological ailments
or disorders such as arthritis (both chronic and temporary) or carpal tunnel syndrome.
Pressure that is insignificant or imperceptible to those unaffected by these disorders may
be very painful, or render a device unusable, for those who are. Many ergonomically designed
products are also used or recommended to treat or prevent such disorders, and to treat pressure-related
chronic pain. One of the most prevalent types of work-related
injuries are musculoskeletal disorders. Work-related musculoskeletal disorders (WRMDs) result in
persistent pain, loss of functional capacity and work disability, but their initial diagnosis
is difficult because they are mainly based on complaints of pain and other symptoms.
Every year 1.8 million U.S. workers experience WRMDs and nearly 600,000 of the injuries are
serious enough to cause workers to miss work. Certain jobs or work conditions cause a higher
rate worker complaints of undue strain, localized fatigue, discomfort, or pain that does not
go away after overnight rest. These types of jobs are often those involving activities
such as repetitive and forceful exertions; frequent, heavy, or overhead lifts; awkward
work positions; or use of vibrating equipment. The Occupational Safety and Health Administration
(OSHA) has found substantial evidence that ergonomics programs can cut workers' compensation
costs, increase productivity and decrease employee turnover. Therefore, it is important
to gather data to identify jobs or work conditions that are most problematic, using sources such
as injury and illness logs, medical records, and job analyses.
Cognitive ergonomics Cognitive ergonomics is concerned with mental
processes, such as perception, memory, reasoning, and motor response, as they affect interactions
among humans and other elements of a system. (Relevant topics include mental workload,
decision-making, skilled performance, human-computer interaction, human reliability, work stress
and training as these may relate to human-system and Human-Computer Interaction design.)
Organizational ergonomics Organizational ergonomics is concerned with
the optimization of socio-technical systems, including their organizational structures,
policies, and processes. (Relevant topics include communication, crew resource management,
work design, work systems, design of working times, teamwork, participatory design, community
ergonomics, cooperative work, new work programs, virtual organizations, telework, and quality
management.) History of the field
In ancient societies The foundations of the science of ergonomics
appear to have been laid within the context of the culture of Ancient Greece. A good deal
of evidence indicates that Greek civilization in the 5th century BC used ergonomic principles
in the design of their tools, jobs, and workplaces. One outstanding example of this can be found
in the description Hippocrates gave of how a surgeon's workplace should be designed and
how the tools he uses should be arranged. The archaeological record also shows that
the early Egyptian dynasties made tools and household equipment that illustrated ergonomic
principles. In industrial societies
In the 19th century, Frederick Winslow Taylor pioneered the "scientific management" method,
which proposed a way to find the optimum method of carrying out a given task. Taylor found
that he could, for example, triple the amount of coal that workers were shoveling by incrementally
reducing the size and weight of coal shovels until the fastest shoveling rate was reached.
Frank and Lillian Gilbreth expanded Taylor's methods in the early 1900s to develop the
"time and motion study". They aimed to improve efficiency by eliminating unnecessary steps
and actions. By applying this approach, the Gilbreths reduced the number of motions in
bricklaying from 18 to 4.5, allowing bricklayers to increase their productivity from 120 to
350 bricks per hour. However this approach was rejected by Russian
researchers who focused on the well being of the worker. At the First Conference on
Scientific Organization of Labour (1921) Vladimir Bekhterev and Vladimir Nikolayevich Myasishchev
criticised Taylorism. Bekhterev argued that "The ultimate ideal of the labour problem
is not in it, but is in such organisation of the labour process that would yield a maximum
of efficiency coupled with a minimum of health hazards, absence of fatigue and a guarantee
of the sound health and all round personal development of the working people." Myasishchev
rejected Frederick Taylor's proposal to turn man into a machine. Dull monotonous work was
a temporary necessity until a corresponding machine can be developed. He also went on
to suggest a new discipline of "ergology" to study work as an integral part of the re-organisation
of work. The concept was taken up by Myasishchev's mentor, Bekhterev, in his final report on
the conference, merely changing the name to "ergonology"
In aviation Prior to World War I the focus of aviation
psychology was on the aviator himself, but the war shifted the focus onto the aircraft,
in particular, the design of controls and displays, the effects of altitude and environmental
factors on the pilot. The war saw the emergence of aeromedical research and the need for testing
and measurement methods. Studies on driver behaviour started gaining momentum during
this period, as Henry Ford started providing millions of Americans with automobiles. Another
major development during this period was the performance of aeromedical research. By the
end of World War I, two aeronautical labs were established, one at Brooks Air Force
Base, Texas and the other at Wright-Patterson Air Force Base outside of Dayton, Ohio. Many
tests were conducted to determine which characteristic differentiated the successful pilots from
the unsuccessful ones. During the early 1930s, Edwin Link developed the first flight simulator.
The trend continued and more sophisticated simulators and test equipment were developed.
Another significant development was in the civilian sector, where the effects of illumination
on worker productivity were examined. This led to the identification of the Hawthorne
Effect, which suggested that motivational factors could significantly influence human
performance. World War II marked the development of new
and complex machines and weaponry, and these made new demands on operators' cognition.
It was no longer possible to adopt the Tayloristic principle of matching individuals to preexisting
jobs. Now the design of equipment had to take into account human limitations and take advantage
of human capabilities. The decision-making, attention, situational awareness and hand-eye
coordination of the machine's operator became key in the success or failure of a task. There
was a lot of research conducted to determine the human capabilities and limitations that
had to be accomplished. A lot of this research took off where the aeromedical research between
the wars had left off. An example of this is the study done by Fitts and Jones (1947),
who studied the most effective configuration of control knobs to be used in aircraft cockpits.
A lot of this research transcended into other equipment with the aim of making the controls
and displays easier for the operators to use. The entry of the terms "human factors" and
"ergonomics" into the modern lexicon date from this period. It was observed that fully
functional aircraft flown by the best-trained pilots, still crashed. In 1943 Alphonse Chapanis,
a lieutenant in the U.S. Army, showed that this so-called "pilot error" could be greatly
reduced when more logical and differentiable controls replaced confusing designs in airplane
cockpits. After the war, the Army Air Force published 19 volumes summarizing what had
been established from research during the war.
In the decades since World War II, HF&E has continued to flourish and diversify. Work
by Elias Porter and others within the RAND Corporation after WWII extended the conception
of HF&E. "As the thinking progressed, a new concept developed—that it was possible to
view an organization such as an air-defense, man-machine system as a single organism and
that it was possible to study the behavior of such an organism. It was the climate for
a breakthrough." In the initial 20 years after the World War II, most activities were
done by the "founding fathers": Alphonse Chapanis, Paul Fitts, and Small.
During the cold war The beginning of The Cold War led to a major
expansion of Defense supported research laboratories. Also, many labs established during WWII started
expanding. Most of the research following the war was military-sponsored. Large sums
of money were granted to universities to conduct research. The scope of the research also broadened
from small equipments to entire workstations and systems. Concurrently, a lot of opportunities
started opening up in the civilian industry. The focus shifted from research to participation
through advice to engineers in the design of equipment. After 1965, the period saw a
maturation of the discipline. The field has expanded with the development of the computer
and computer applications. The Space Age created new human factors issues
such as weightlessness and extreme g-forces. Tolerance of the harsh environment of space
and its effects on the mind and body were widely studied
Information age The dawn of the Information Age has resulted
in the related field of human–computer interaction (HCI). Likewise, the growing demand for and
competition among consumer goods and electronics has resulted in more companies and industries
including human factors in their product design. Using advanced technologies in human kinetics,
body-mapping, movement patterns and heat zones, companies are able to manufacture purpose-specific
garments, including full body suits, jerseys, shorts, shoes, and even underwear.
HF&E organizations Formed in 1946 in the UK, the oldest professional
body for human factors specialists and ergonomists is The Institute of Ergonomics and Human Factors,
formally known as The Ergonomics Society. The Human Factors and Ergonomics Society (HFES)
was founded in 1957. The Society's mission is to promote the discovery and exchange of
knowledge concerning the characteristics of human beings that are applicable to the design
of systems and devices of all kinds. The International Ergonomics Association (IEA)
is a federation of ergonomics and human factors societies from around the world. The mission
of the IEA is to elaborate and advance ergonomics science and practice, and to improve the quality
of life by expanding its scope of application and contribution to society. As of September
2008, the International Ergonomics Association has 46 federated societies and 2 affiliated
societies. Related organizations
The Institute of Occupational Medicine (IOM) was founded by the coal industry in 1969,
from the outset the IOM employed ergonomics staff to apply ergonomics principles to the
design of mining machinery and environments. To this day, the IOM continues ergonomics
activities, especially in the fields of musculoskeletal disorders; heat stress and the ergonomics
of personal protective equipment (PPE). Like many in occupational ergonomics, the demands
and requirements of an ageing UK workforce are a growing concern and interest to IOM
ergonomists. The International Society of Automotive Engineers
(SAE) is a professional organization for mobility engineering professionals in the aerospace,
automotive, and commercial vehicle industries. The Society is a standards development organization
for the engineering of powered vehicles of all kinds, including cars, trucks, boats,
aircraft, and others. The Society of Automotive Engineers has established a number of standards
used in the automotive industry and elsewhere. It encourages the design of vehicles in accordance
with established Human Factors principles. It is one of the most influential organizations
with respect to Ergonomics work in Automotive design. This society regularly holds conferences
which address topics spanning all aspects of Human Factors/Ergonomics.
Practitioners Human factors practitioners come from a variety
of backgrounds, though predominantly they are psychologists (from the various subfields
of industrial and organizational psychology, engineering psychology, cognitive psychology,
perceptual psychology, applied psychology, and experimental psychology) and physiologists.
Designers (industrial, interaction, and graphic), anthropologists, technical communication scholars
and computer scientists also contribute. Typically, an ergonomist will have an undergraduate degree
in psychology, engineering, design or health sciences, and usually a masters degree or
doctoral degree in a related discipline. Though some practitioners enter the field of human
factors from other disciplines, both M.S. and PhD degrees in Human Factors Engineering
are available from several universities worldwide. The Human Factors Research Group (HFRG) at
the University of Nottingham provides human factors courses at both at MSc and PhD level
including a distance learning course in Applied Ergonomics. Other Universities to offer postgraduate
courses in human factors in the UK include Loughborough University, Cranfield University
and the University of Oxford. Methods
Until recently, methods used to evaluate human factors and ergonomics ranged from simple
questionnaires to more complex and expensive usability labs. Some of the more common HF&E
methods are listed below: Ethnographic analysis: Using methods derived
from ethnography, this process focuses on observing the uses of technology in a practical
environment. It is a qualitative and observational method that focuses on "real-world" experience
and pressures, and the usage of technology or environments in the workplace. The process
is best used early in the design process. Focus Groups are another form of qualitative
research in which one individual will facilitate discussion and elicit opinions about the technology
or process under investigation. This can be on a one to one interview basis, or in a group
session. Can be used to gain a large quantity of deep qualitative data, though due to the
small sample size, can be subject to a higher degree of individual bias. Can be used at
any point in the design process, as it is largely dependent on the exact questions to
be pursued, and the structure of the group. Can be extremely costly.
Iterative design: Also known as prototyping, the iterative design process seeks to involve
users at several stages of design, in order to correct problems as they emerge. As prototypes
emerge from the design process, these are subjected to other forms of analysis as outlined
in this article, and the results are then taken and incorporated into the new design.
Trends amongst users are analyzed, and products redesigned. This can become a costly process,
and needs to be done as soon as possible in the design process before designs become too
concrete. Meta-analysis: A supplementary technique used
to examine a wide body of already existing data or literature in order to derive trends
or form hypotheses in order to aid design decisions. As part of a literature survey,
a meta-analysis can be performed in order to discern a collective trend from individual
variables. Subjects-in-tandem: Two subjects are asked
to work concurrently on a series of tasks while vocalizing their analytical observations.
The technique is also known as "Co-Discovery" as participants tend to feed off of each other's
comments to generate a richer set of observations than is often possible with the participants
separately. This is observed by the researcher, and can be used to discover usability difficulties.
This process is usually recorded. Surveys and Questionnaires: A commonly used
technique outside of Human Factors as well, surveys and questionnaires have an advantage
in that they can be administered to a large group of people for relatively low cost, enabling
the researcher to gain a large amount of data. The validity of the data obtained is, however,
always in question, as the questions must be written and interpreted correctly, and
are, by definition, subjective. Those who actually respond are in effect self-selecting
as well, widening the gap between the sample and the population further.
Task analysis: A process with roots in activity theory, task analysis is a way of systematically
describing human interaction with a system or process to understand how to match the
demands of the system or process to human capabilities. The complexity of this process
is generally proportional to the complexity of the task being analyzed, and so can vary
in cost and time involvement. It is a qualitative and observational process. Best used early
in the design process. Think aloud protocol: Also known as "concurrent
verbal protocol", this is the process of asking a user to execute a series of tasks or use
technology, while continuously verbalizing their thoughts so that a researcher can gain
insights as to the users' analytical process. Can be useful for finding design flaws that
do not affect task performance, but may have a negative cognitive affect on the user. Also
useful for utilizing experts in order to better understand procedural knowledge of the task
in question. Less expensive than focus groups, but tends to be more specific and subjective.
User analysis: This process is based around designing for the attributes of the intended
user or operator, establishing the characteristics that define them, creating a persona for the
user. Best done at the outset of the design process, a user analysis will attempt to predict
the most common users, and the characteristics that they would be assumed to have in common.
This can be problematic if the design concept does not match the actual user, or if the
identified are too vague to make clear design decisions from. This process is, however,
usually quite inexpensive, and commonly used. "Wizard of Oz": This is a comparatively uncommon
technique but has seen some use in mobile devices. Based upon the Wizard of Oz experiment,
this technique involves an operator who remotely controls the operation of a device in order
to imitate the response of an actual computer program. It has the advantage of producing
a highly changeable set of reactions, but can be quite costly and difficult to undertake.
Methods Analysis is the process of studying the tasks a worker completes using a step-by-step
investigation. Each task in broken down into smaller steps until each motion the worker
performs is described. Doing so enables you to see exactly where repetitive or straining
tasks occur. Time studies determine the time required for
a worker to complete each task. Time studies are often used to analyze cyclical jobs. They
are considered “event based” studies because time measurements are triggered by the occurrence
of predetermined events. Work sampling is a method in which the job
is sampled at random intervals to determine the proportion of total time spent on a particular
task. It provides insight into how often workers are performing tasks which might cause strain
on their bodies. Predetermined time systems are methods for
analyzing the time spent by workers on a particular task. One of the most widely used predetermined
time system is called Methods-Time-Measurement (MTM). Other common work measurement systems
include MODAPTS and MOST. Industry specific applications based on PTS are Seweasy and
GSD. Cognitive Walkthrough: This method is a usability
inspection method in which the evaluators can apply user perspective to task scenarios
to identify design problems. As applied to macroergonomics, evaluators are able to analyze
the usability of work system designs to identify how well a work system is organized and how
well the workflow is integrated. Kansei Method: This is a method that transforms
consumer’s responses to new products into design specifications. As applied to macroergonomics,
this method can translate employee’s responses to changes to a work system into design specifications.
High Integration of Technology, Organization, and People (HITOP): This is a manual procedure
done step-by-step to apply technological change to the workplace. It allows managers to be
more aware of the human and organizational aspects of their technology plans, allowing
them to efficiently integrate technology in these contexts.
Top Modeler: This model helps manufacturing companies identify the organizational changes
needed when new technologies are being considered for their process.
Computer-integrated Manufacturing, Organization, and People System Design (CIMOP): This model
allows for evaluating computer-integrated manufacturing, organization, and people system
design based on knowledge of the system. Anthropotechnology: This method considers
analysis and design modification of systems for the efficient transfer of technology from
one culture to another. Systems Analysis Tool (SAT): This is a method
to conduct systematic trade-off evaluations of work-system intervention alternatives.
Macroergonomic Analysis of Structure (MAS): This method analyzes the structure of work
systems according to their compatibility with unique sociotechnical aspects.
Macroergonomic Analysis and Design (MEAD): This method assesses work-system processes
by using a ten-step process. Virtual Manufacturing and Response Surface
Methodology (VMRSM): This method uses computerized tools and statistical analysis for workstation
design. Weaknesses of HF&E methods
Problems related to usability measures are employed include the fact that measures of
learning and retention of how to use an interface are rarely employed during methods and some
studies treat measures of how users interact with interfaces as synonymous with quality-in-use,
despite an unclear relation. Although field methods can be extremely useful
because they are conducted in the users natural environment, they have some major limitations
to consider. The limitations include: Usually take more time and resources than
other methods Very high effort in planning, recruiting,
and executing than other methods Much longer study periods and therefore requires
much goodwill among the participants Studies are longitudinal in nature, therefore,
attrition can become a problem.