Topic 1 1.1a Anthropometrics Design is human centred and, therefore, designers need to ensure that the products they design are the right size for the user and therefore are comfortable to use. Designers have access to data and drawings, which state measurements of human beings of all ages and sizes. Designers need to consider how users will interact with the product or service. 1.5 Design is human centred and focuses on the needs, wants and limitations of the end user 1.18 Designers must consider how users will interact with, use and misuse the products they design 1.20 Design Permeates every aspect of human experience. Individuals make design decisions in all areas of their work, home and leisure. International Mindedness A wide selection of anthropometric data is published and regionalised, for example, Asian data v European data. The designer must work with data appropriate to the target market. Essential Idea: Designers consider three human factors to ensure products meet ergonomic needs.
Transcript
Topic 1
1.1a Anthropometrics
Design is human centred and, therefore, designers need to ensure that the products they design are the right size for the user and therefore are comfortable to use. Designers have access to data and drawings, which state measurements of human beings of all ages and sizes. Designers need to consider how users will interact with the product or service.
1.5 Design is human centred and focuses on the needs, wants and limitations of the end user
1.18 Designers must consider how users will interact with, use and misuse the products they design
1.20 Design Permeates every aspect of human experience. Individuals make design decisions in all areas of their work, home and leisure.
International Mindedness
A wide selection of anthropometric data is published and regionalised, for example, Asian data v European data. The designer must work with data appropriate to the target market.
Essential Idea: Designers consider three human factors to ensure products meet ergonomic needs.
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Anthropometric DataAnthropometric Data: The measurement and collection of data concerning the different sizes of men, women and children.
Anthropometric data is more than a simple measurement, it can be sub-classified as
Static Data (also known as Structural data)…...this refers to measurements taken while while the subject is in a fixed or standard position, e.g. height, arm length
Dynamic Data (also known as Functional data)…..this refers to measurements taken during physical activities, e.g. crawling height, overhead reach and a range of upper body movements.
Static data is much easier to gather, as people are asked to remain still while measurements are taken. Dynamic data involves people carrying out tasks. People carry out tasks in many different ways. While static data is more reliable, dynamic data is often more useful.
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User Populations It is important to consider the intended User Population for any product (or system) you are designing. It can be defined as the range of users for a particular product or system. these can be defined by age, gender, physical condition, socio-economic class etc.
Population StereotypesPopulation stereotypes: responses that are found to be widespread in a user population. “Long-term habits andwell-ingrained knowledge that we have about the world” (Kantowitz & Sorkin, 1983).
When walking into a room, assuming it is dark, what way would you flip a toggle switch to turn the lights on? You have two choices, up flip or down flip.
Indeed, most Americans think that up is on but in other countries, the opposite is true.Making use of population stereotypes in the design of the controls for products is relevant. It is usually anti clockwise for ‘on’ when dealing with fluids and gases (a tap) and clockwise for ‘on’ when dealing with mechanical products (a radio). Population stereotypes can be displaced (changed or relearned) by alternative learnt responses, but they frequently reassert (return) under conditions of stress such as tiredness or panic.
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Collecting Anthropometric DataThe actual data is collected using a range of different tools, sliding calipers, skinfold calipers, fabric tapes and stadiometers.
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Percentiles
When data has been collected and placed into a table for analysis, it is almost always going to look like the graph shown. The graph below shows the height of a group of adults.
First, notice that the graph is symmetrical – so that 50% of people are of average height or taller, and 50% are of average height or smaller. The graph tails off to either end, because fewer people are extremely tall or very short. To the left of the average, there is a point known as the 5th percentile, because 5% of the people (or 1 person in 20) is shorter than this particular height. The same distance to the right is a point known as the 95th percentile, where only 1 person in 20 is taller than this height. So, we also need to know whether we are designing for all potential users or just the ones of above or below average dimensions. Now, this depends on exactly what it is that we are designing.
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How are percentiles used?Referring back to the graph on the previous page. Let's say the adult population makes up 100%, researchers break down the group into 100 percentile groups with the first percentile being the smallest and the 100th percentile being the largest. As designers, most of the time, it suffices to limit ourselves to dealing with the 5th to the 95th percentile, meaning that we would cover 90 out of 100 adults.A constant problem for designers is the conflict between designing for as wide variety of people as possible, and, at the same time, helping the manufacturer to keep the production costs down.For example, if we were designing a doorway using the height, shoulder width, hip width etc., of an averageperson, then half the people using the doorway would be taller than the average, and half would be wider.Since the tallest people are not necessarily the widest, more than half the users would have to bend downor turn sideways to get through the doorway. Therefore, in this case we would need to design usingdimensions of the widest and tallest people to ensure that everyone could walk through normally.Deciding whether to use the 5th, 50th or 95th percentile value depends on what you are designing andwho you are designing it for.
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Usually, you will find that if you pick the right percentile, 95% of people will be able to use your design. Forinstance, if you were choosing a door height, you would choose the dimension of people's height (oftencalled 'stature' in anthropometry tables) and pick the 95th percentile value – in other words, you woulddesign for the taller people. You wouldn't need to worry about the average height people, or the 5thpercentile ones – they would be able to fit through the door anyway.
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At the other end of the scale, if you were designing an aeroplane cockpit, and needed to make sureeveryone could reach a particular control, you would choose 5th percentile arm length – because thepeople with the short arms are the ones who are most challenging to design for. If they could reach thecontrol, everyone else (with longer arms) would be able to. This should also reinforce the requirement to ensure users can safely interact with their environments.
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Primary and Secondary Anthropometric Data
As this suggests, there are 2 forms of info. There are many many secondary sources of anthropometric data available, both in print and on-line. This is probably where most of your data will come from. However, if you have a particular client or access to the user population you wish to design for, you may wish to collect measurements yourself and generate your own primary data.
As mentioned in the first slide, it is important to consider the reliability of the data you are using or generating. For secondary sources, is it appropriate in terms of age, gender, race or geographic region.
If it is primary data, consider the conditions under which it was collected, were the subjects wearing bulky clothing, or gloves? If it was a particularly hot/cold day, the measurements collected may not be that reliable.
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Range of Size and Adjustability
Certain products tend to be available in different sizes or with adjustability built in as there really is no ‘one size fits all’. Consider the following examples:
Clothing comes in a range of sizes. For manufacturers to make clothing fit every individual variance would not be economically possible, thus it tends to come in a range of sizes based on percentile ranges.
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Adjustability
Children’s car seats are adjustable to
allow for a range of sizes and a growing
child.
Ironing tables can be adjusted to allow for people of a different height to use comfortably.This has an effect on the design of the legs, as this is how the board is adjusted in height.
As are other items in a car, such as adjustable seat backs, adjustable leg room, adjustable seat belts, adjustable steering wheels, adjustable mirrors, adjustable headrest, etc.
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Percentile Ranges
Which user population and percentile ranges would be required for the following products? Are all of the measurements neccessary?
Sitting height:
Leg room:
Arm reach:
Viewing angles:
Hip breadth:
Thigh length:
Childs Car Seat
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Percentile Ranges
Sitting height:
Leg room:
Arm reach:
Viewing angles:
Hip breadth:
Thigh length:
Office Chair
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Clearance, Reach and Adjustability
Clearance
Sometimes people or machines have to move
through or work in restricted areas, for example,
maintenance work. Clearance can be seen as the
minimum distance required to, enable the user
group into or through an area. This is especially
important when designing emergency exits and
safety hatches
Reach-The workspace envelope.
A 'workspace envelope' is a 3-dimensional space within which you carry
out physical work activities when you are at a fixed location. The limits of
the envelope are determined by your functional arm reach which, in turn,
is influenced by the direction of reach and the nature of the task being
performed. Most of the things that you need to use to carry out your
tasks should be arranged within this area. Workspace envelopes should
be designed for the 5th percentile of the user population, which means
that 95% of users will be able to reach everything placed within the
envelope.
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Examples
What are aiming for with your design? Design examples: Examples of measurements to consider:
Adequate clearance to avoid unwanted contact or trapping
Service Covers, Cinema seats Shoulder or hip width, Thigh length
Largest user: 95th percentile
A good match between the user and the product
Seats,
Cycle helmets, Pushchairs
Knee-floor height, Head circumference, Weight
Maximum range: 5th to95th percentile
A comfortable and safe posture Lawnmowers, Monitor positions, Worksurface heights
Elbow height, Sitting eye height,
Elbow height (sitting or standing?)
Maximum range: 5th to95th percentile
Easy operation Screw bottle tops, Door handles, Light switches
Grip strength, Hand width, Height Smallest or weakest user: 5th percentile
To ensure that an item can't be reached or operated
Machine guarding mesh,
Distance of railings from hazard
Finger width
Arm length
Smallest user: 5th percentile
Largest user: 95th percentile
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1.1b Psychological factorsEssential Idea: Designers consider three human factors to ensure products meet ergonomic needs
Nature of Design:Human beings vary psychologically in complex ways. Any attempt by designers to classify people into groups merely results in a statement of broad principles that may or may not be relevant to the individual. Design permeates every aspect of human experience and data pertaining to what cannot be seen such as touch, taste, and smell are often expressions of opinion rather than checkable fact.
Concepts and principles:● Psychological factor data● Human information processing systems● Effect of environmental factors● Alertness● Perception
Guidance:● Data in relation to light, smell, sound, taste, temperature and texture as qualitative or
quantitative (ordinal/interval)● Methods of collecting psychological factor data● Representing the human information processing system using flow diagrams● Applying the human information processing system to a common task● Evaluating effects and reasons for breakdown in the human information processing system● User responses to environmental factors● How environmental factors induce different levels of alertness● The importance of optimizing environmental factors to maximize workplace performance● Assessing the impact of perception in relation to the accuracy and reliability of psychological
factor data
Human error & Human Information pocessinghttp://nas.psych.uidaho.edu/~ad.uidaho.edu%5Cbdyre/psyc562/readings/Human_Reliability_and_Error/Sharit(2006).pdf
Pedestrian urbanisation - Human Factorshttp://trid.trb.org/view.aspx?id=114653
book: Human Errorhttp://www.google.com.hk/books?hl=en&lr=&id=CT_wFPljJ-EC&oi=fnd&pg=PR17&dq=human+factors+Psychological+factors&ots=SqD8UVqcwP&sig=FosbtPtezUQyiWuuhPWjJylmAFg&redir_esc=y#v=onepage&q=human%20factors%20Psychological%20factors&f=falsePDF Copyhttp://nas.psych.uidaho.edu/~ad.uidaho.edu%5Cbdyre/psyc562/readings/Human_Reliability_and_Error/Sharit(2006).pdf
Cognitive psychology / 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.
In their everyday practical work ergonomists may well be more interested in improving what people do rather than what people know or feel. However an enduring improvement of performance seems to be possible only if the underlying cognitive representations as well as attitudes and competences of participating persons are known. This is why, the Chomskian distinction between competence and performance become very important for cognitive ergonomists (Amalberti, 2001).
This is a great example with excellent information and examples based on FOODChapter 3 - Sensory Evaluation - Sung Eun Choi, PhD,EDhttp://samples.jbpub.com/9781449694777/9781449603441_CH03.pdf
Psychological factor data● Data in relation to light, smell, sound, taste, temperature and texture as qualitative or
quantitative (ordinal/interval)
Noah Iliinsky provides a good, high-level description of the visual processing center in his article, “Why is Data Visualization So Hot“:
… fundamentally, our visual system is extremely well built for visual analysis. There’s a huge
amount of data coming into your brain through your eyes; the optic nerve is a very big pipe,
and it sends data to your brain very quickly (one study estimates the transmission speed of
the optic nerve at around 9Mb/sec). Once that data arrives at the brain, it’s rapidly processed
by sophisticated software that’s extremely good at tasks such as edge detection, shape
recognition, and pattern matching.
How do we map that knowledge onto data? As we discussed earlier this semester, there are types of measurement: nominal, ordinal, interval, and ratio. Most data that you are interested in will be one of those four types. Mapping human capability to these levels of measurements is the key to visualizing data. For example, we can easily distinguish between the colors blue and red (at least most sighted people can). However, blue and red don’t have a natural ordering. There is no reason to think that something colored red is worth more or greater than something colored blue. Color is good at distinguishing members in a group, otherwise known as nominal measurements, but would be a poor choice for differentiating ordered elements, or ordinal measurements. For ordinal measurements, shades of grey work well. Shades of grey are easy to distinguish and have a natural ordering.Data visualization relies on vision, but vision is just one sense.
● Data in relation to light, smell, sound, taste, temperature and texture as qualitative or quantitative (ordinal/interval)
In Paul Auster’s mediocre novel Timbuktu, the human protagonist attempts to create for his dog companion a Symphony of Smells, figuring that dogs’ strongest sense is their sense of smell, so they should be able to appreciate odors more than colors or sounds. For humans without sight (and even those with sight), “visualizing” data through scent can be powerful on many levels. The main challenges, as I see them, are twofold. First, scent is subjective (I may be weird, but I love the smell of cow manure). Scent can invoke emotion, but the smell of fresh cut grass to a rich kid may signify the start of little league season, while on the other side of the tracks, it may evoke backbreaking hours cutting lawns. Second, if one could get past the subjectivity, how would a data scientist quantify scent?These would be important questions to answer because, according to artist Kate McLean, we have 100% smell recall after one year, but only 30% sight memory after three months. She would know because she has created “smell maps” of cities around the world (her research is here: http://www.sensorymaps.com/index.html). These beautiful, three dimensional creations try to capture the changing smells of a place at a granular level. Of course, her process involves visualizing scent, but imagine how powerful those maps could be if she could capture that scent and expose users of her maps to them.
Psychological factor data● Methods of collecting psychological factor data
Qualitative psychological research is where the research findings are not arrived at by statistical or other quantitative procedures. Quantitative psychological research is where the research findings result from mathematical modeling and statistical estimation or statistical inference. Since qualitative information can be handled as such statistically, the distinction relates to method, rather than the topic studied.
http://youtu.be/UPCItrMUNXY
http://youtu.be/C1FQf3Rpu4c
http://youtu.be/zWmH2IGK--s
http://youtu.be/F8EyAoPyFKI
Look at and subscrib4e to: https://www.youtube.com/channel/UCK4KMPJbJSaRtRY_MxSUzlw
• There are 4 main scales used when collecting ergonomic data.
• Nominal• Ordinal• Interval• Ratio data scales.
Nominal scale• Experiments need data. To get data, a
researcher must measure something. Measurements come in many different varieties. For example, it is possible to measure time, weight, length, number of responses, height, pleasantness and brightness. The way numbers represent a particular measurement is called the "scale" (scales of measurement). A nominal scale classifies data according to a category only. For example, an experiment may examine
• which colour people select. No assumptions are made that any colour has more or less value than any other color. Colours differ qualitatively from one another, but they do not differ quantitatively. A number could be assigned to each colour, but it would not have any value. The number serves only to identify the colour.
ordinal scale• As with nominal scales, the labels used in ordinal scales
can be words, symbols, letters or numerals.• When numerals are used, they only indicate sequence or
order, for example, ranking someone by placing them in a competition as “third” rather than by a score—they may have come third with 50% right or with
• 75%. An ordinal scale classifies data according to rank. With ordinal data, it is fair to say that one response
• is greater or less than another. For example, if people were asked to rate the hotness of three chili peppers,
• a scale of "hot", "hotter" and "hottest" could be used. Values of "1" for "hot", "2" for "hotter" and "3" for "hottest" could be assigned. However, and this is important, you cannot say that the difference between the hot pepper and the hotter pepper is the same as the difference between the hotter pepper and the hottest pepper. It may be that you can eat a hot pepper without feeling any pain. You may also be able to eat the hotter pepper, but your mouth just tingles a bit. However, the hottest pepper is really, really hot...so hot your whole mouth burns.
Interval scale• An interval scale is a more powerful
scale, as the intervals or difference between the points or units are of an equal size, for example, in a temperature scale. Measurements using an interval scale can be subjected to numerical or quantitative analysis. An interval scale assumes that the measurements are made unequal units. However, an interval scale does not have to have a true zero. Good examples of interval scales are the Fahrenheit and Celsius temperature scales. A temperature of "zero" does not mean that there is no temperature...it is just an arbitrary zero point.
Ratio Scale
• The difference between a ratio scale and an interval scale is that the zero point on an interval scale is some arbitrarily agreed value, whereas on a ratio scale it is a true zero. For example, 0°C has been defined arbitrarily as the freezing temperature of water, whereas 0 grams is a true zero, that is, no mass. Ratio scales are similar to interval scales. A ratio scale allows you to compare differences between numbers. For example, if you measured the time it takes 3 people to run a race, their times may be 10 seconds (Racer A), 15 seconds (Racer B) and 20 seconds (Racer C). You can say with accuracy, that it took Racer C twice as long as Racer A. Unlike the interval scale, the ratio scale has a true zero value.
Representing the human information
processing system using flow diagrams
• The human information processing system can be represented by an information flow diagram
• The arrows represent the flow of information through the system. The boxes represent functional elements in the processing chain, where information is processed
Applying the human information processing
system to a common task.
• The arrows represent the flow of information through the system. The boxes represent functional elements in the processing chain, where information is processed:
• The input would be the number to be called • The sensory processes would be the eyes, which would transmit
information to the brain • The brain is the central processing unit, which examines the
information and • selects a response coded as a series of nerve impulses
transmitted to the hand and muscles, these are the motor processes
• There are four fundamental assumptions – or four pillars – of the information processing approach. These pillars underlay and support this approach, as well as many other cognitive models.
Thinking:• The process of thinking includes the activities of
perception of external stimuli, encoding the same and storing the data so perceived and encoded in one's mental recesses.
Analysis of stimuli:• This is the process by which the encoded stimuli
are altered to suit the brain's cognition and interpretation process to enable decision making. There are four distinct sub-processes that form a favourable alliance to make the brain arrive at a conclusion regarding the encoded stimuli it has received and kept stored. These four sub-processes are encoding, strategization, generalization and automatization.
Situational modification:
• This is the process by which an individual uses his experience, which is nothing other than a collection of stored memories, to handle a similar situation in future. In case of certain differences in both situations, the individual modifies the decisions they took during their previous experience to come up with solutions for the somewhat different problem.
Obstacle evaluation:• This step maintains that besides the subject's
individual development level, the nature of the obstacle or problem should also be taken into consideration while evaluating the subject's intellectual, problem solving and cognitive acumen. Sometimes, unnecessary and misleading information can confuse the subject and he / she may show signs of confusion while dealing with a situation which is similar to one he / she was exposed to before, which he / she was able to handle successfully.
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How environmental factors induce different levels of alertness,
This picture shows the inside of one of the main doors in a large commercial jetliner. After closing the door, the flight attendant attaches the emergency slide on the inside of the door. After attaching the slide, the attendant attaches this red strip across the window. It is meant to signal to a person outside to not open the door. Opening the door could be deadly since the emergency slide would automatically inflate. It seems like it would be very easy to forget to attach the red strip.
The importance of controlling
environmental factors to, maximise
workplace, performance• The influence of the psychological human
factors of noise and temperature on the design of an open-plan office
• Consideration should be made for sound-absorbing acoustic partitions to keep noise of conversations isolated. Noisy equipment such as photocopiers and printers might be also isolated in a separate area.
• Low silent phone tones, ventilation flow, static and dynamic tasks also need to be considered to make the environment effective and productive. Space is often allocated based on standardized tasks or office status,
• Office environments are more beneficial if they are well lit with natural lighting and have some natural influences such as the use of timber and views and use of indoor and outdoor plants.
• Office environments are more beneficial if they are well lit with natural lighting and have some natural influences such as the use of timber and views and
use of indoor and outdoor plants.
Assessing the impact of perception in
relation to the accuracy and reliability of
psychological factor data.• Psychology is an area of human factors is an area of that
focuses on a range of different topics, including ergonomics, workplace safety, human error, product design, human capability, and human-computer interaction. In fact, the terms human factors and ergonomics are often used synonymously, with human factors being commonly used in the United States and ergonomics in Europe.
• Human factors works to apply principles of psychology to designing products and creating work environments that boost productivity while minimizing safety issues. The field of human factors formally began during World War II, when a range of experts worked together to improve the safety of airplanes.
What Makes Human Factors Psychology
Different?
• Human factors psychology is generally very applied, with most employed in this area working directly in the field. Psychologists working in human factors spend much of their time performing research and applying what they know about human behavior, perception, and cognition to create more usable products and work environments.
• Cognition• Perception• Educational technology• Graphic design• Instructional message design• Human capabilities and limitations in specific work areas• The use of virtual reality in employee training• Problems that may arise from collecting this type of data
is that people’s perception can differ and often it can give inaccurate results. Also it does not take into account adverse or stressful situations and population steryotypes.
Situation awareness
• is the perception of environmental elements with respect to time and/or space, the comprehension of their meaning, and the projection of their status after some variable has changed, such as time, or some other variable, such as a predetermined event. It is also a field of study concerned with perception of the environment critical to decision-makers in complex, dynamic areas from aviation, air traffic control, ship navigation, power plant operations, military command and control, and emergency services such as fire fighting and policing; to more ordinary but nevertheless complex tasks such as driving an automobile or bicycle.
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1.1c Physiological Factors
Nature of design: Designers study physical characteristics to optimize the user’s safety, health, comfort and performance.
(1.5, 1.18, 1.20, 2.9)
Concepts and principles:
● Physiological factor data
● Comfort and fatigue
● Biomechanics
Guidance:● Types of physiological factor data available to designers and how they are collected● How data related to comfort and fatigue informs design decisions● The importance of biomechanics to the design of different products considering
muscle strength, age, user interface and torque
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Physiological factor dataTypes of physiological factor data available to designers and how they are collected
When designing industrial or consumer products, physiological factors must be taken into accountie. how users interact with products and specifically their physical comfort.
Physiological factors that affect ergonomics:
● Physical limitations● How the body moves● Hand/eye coordination● Strength● Size● Stamina - muscle strength/endurance in different body positions● Visual sensitivity ie. to light● Tolerance to extremes of temperature● Frequency and range of human hearing
Body Tolerances: How much the body can withstand when using or working with a product
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Comfort and FatigueCOMFORT
What is Comfort?
Comfort is of primary concern to designers. It determines how effective a design is and how well a human can interact with a product.
Physical comfort, ie. how pleasing it feels to use a product, is one of the first things a human will notice If something is not pleasant to the touch, people will not want to touch it or ultimately use or operate it.
Comfort in the human-machine interface is usually noticed first. Physical comfort in how an item feels is pleasing to the user. If you do not like to touch it you won't. If you do not touch it you will not operate it. If you do not operate it, then it is useless. The utility of an item is the only true measure of the quality of its design. The job of any designer is to find innovative ways to increase the utility of a product. Making an item intuitive and comfortable to use will ensure its success in the marketplace. Physical comfort while using an item increases its utility. The mental aspect of comfort in the human-machine interface is found in feedback. You have preconceived notions of certain things. A quality product should feel like it is made out of quality materials. If it is light weight and flimsy you will not feel that comfortable using it. The look, feel, use and durability of a product help you make a mental determination about a product or service. Basically it lets you evaluate the quality of the item and compare that to the cost. Better ergonomics mean better quality which means you will be more comfortable with the value of the item.
FATIGUEFatigue is the temporary diminishment of performance. Fatigue can be physical and/or mental.
informs design decisions.• Ergonomics and Design: Applying the Laws of Work• Ergonomics is critical to design. Yet in spite of the fact that many products
are marketed as being ‘ergonomically’ designed it remains a widely misunderstood discipline. The name ‘ergonomics’ means ‘the laws of work;’ derived from the Greek ‘ergon’ (work) and ‘nomos’ (natural laws).
• Formalized in the UK after the end of World War II, it was founded as a human performance oriented engineering design discipline. In the United States the equivalent discipline was called ‘human factors.’ Today both names are used interchangeably, but ‘ergonomics’ probably has greater public recognition because of its use as advertising adjective. It is concerned with the understanding of the interactions among human and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.”
What Do Ergonomists Do?• Human technologysystem framework to analyze and help to improve
adesign. A professionally trained ergonomist will have skills in several specific areas:
• —Physical interface design: to effectively interact with any technology, the physical dimensions of the object must fit the user’s anthropometric dimensions. Anthropometric dimensions are usually expressed as percentiles and most ergonomic designs try to satisfy a range of users, typically from a 5th percentile woman to a 95th percentile man, for any given dimension.
• —Cognitive interface design: knowledge of the principles of information displays associated with the equipment, such as warning signs, labels, instructional materials, and the arrangement of controls (knobs, dials, etc.) are critical to
• product success. Understanding peoples’ reactions to how something looks and their expectations about how it works are critical components of usability.
Workplace design and workspace
layout: the way in which any work • effort to perform the work. Principles
of optimizing workplace layout include:
• 1) convenience—frequently used equipment is most conveniently located;
• 2) location—equipment can be easily accessed without postural deviations (bending, leaning, or twisting); and
• 3) frequency—frequently performed tasks are located together.
Physical environment conditions at
work:
• Job design, selection, and training: these are ways of organizing work activities to maximize work output and quality without adversely affecting workers.
• —Organizational design and management: includes peoples’ motivations and how to best organize them into teams.
• Ergonomic Design: Application of Principles
Ergonomic Design: Application of
Principles
• —Force: movement requires force, but high forces increase injury risks. The amount of force exerted by a muscle group also depends on the body posture.
• —Repetition: high rates of repetitive movements without pauses for recovery can cause cumulative microtrauma that may result in an injury.
• —Posture: every articulating joint in the body has a neutral zone of movement that does not require high muscular force or cause discomfort. Injury risks are minimized when working with body segments in their neutral range rather than outside this in a deviated posture. Poor posture plays a central role in the etiology of musculoskeletal injuries, and ergonomists use postural targeting methods to evaluate product designs and estimate injury risks.
The importance of biomechanics to the design
of a given artifact Product Biomechanical Factors Reason
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NOTES1. Outline physiological factors that affect ergonomics.● fatigue● comfort
● Biomechanics - Application of forces by gravity and muscles
Anthropometry - Dimensions of the body (static and dynamic)
Biomechanics - Application of forces by gravity and muscles
Work - physiology Expenditure of energy
Environmental physiology - Effects on humans of the physical environment
