Adonis Diaries

Posts Tagged ‘efficiency

Article #8, April 5, 2005

“What do you design again?”

Human Factors are primarily oriented to designing interfaces between systems and end users/operators.  Of the many interfaces two interfaces are common to people and can be grouped into two main categories: displays and controls. 

Designing the arrangements of displays and controls on consoles for utility companies, aircraft, trains, and automobiles according to applicable guidelines are examples.

Operators and end users need to receive information on the status of a complex system and be able to respond to this information through a control device. Thus, once a designer knows what needs to be controlled in a system and how, then the required types of displays follow.

Displays and controls can become complex devices if not designed to targeted users.

The design of the cockpit interface in airplanes is different from cars, trains or ships.

The design or the interface in cellular phones is different from computer games or computer screens, keyboards and mouse.

A good knowledge of the physical and mental abilities and requirements of the target end users are paramount in the design of any interface if efficiency, affordability, acceptability, maintainability, safety and health are the prerequisite to wide spread demands and marketability.

How the functions and tasks of any subsystems should be allocated, to human or to an automated machine? 

What are the consequences in emergency situations for any allocation strategy? 

What are the consequences of an allocation when a system is exported to Third World countries? 

What are the consequences of function allocation to employment, safety risks, health risks and long term viability of any system?

Who usually are in charge of designing interfaces that require multidisciplinary knowledge?

Given that any of these designs require inputs from marketing experts, psychologists, sociologists, economists, engineers, statisticians and legal experts on the liabilities of these designed objects for safe and healthy usage then who should be responsible for designing interfaces?

Teams of professionals should necessarily be involved in interface designs but because time being of the essence in business competition and cost to a lesser extent many of these interfaces are relegated to engineers applying published standards or relying on personal experience and previous models from competitors.

Human Factors data on the physical and mental limitations and capabilities of target users should be part of any standard book for designing interfaces.

Human Factors methodologies need to be disseminated so that viable interfaces could fit the characteristics of the end users.

The Human Factors professionals failed in their first three decades of existence to recognize that their main purpose was to design interfaces, to design practical system and to orient their research toward engineers who could readily use their data in designing systems.

If this trend of targeting engineers in our research papers continues then this profession could make a serious dent in sending the proper message and open up a market for the thousands of Human Factors graduates who should be needed in the design of systems interfaces.

Article #35 (Started March 4, 2006)

 “Efficiency of the human body structure”

This article is an on going project to summarize a few capabilities and limitations of man. While the most sophisticated intelligent machines invented by man may contain up to ten thousand elements, the human machine is constituted of up to a million trillion of cells, up to a thousand trillions of neurons in the central nervous system, about a couple hundred bones, and as many organs, muscles, tendons and ligaments.

In the previous article #33 we discussed a graph in a story style and discovered that a human barefoot in texture, shape, and toes has a higher coefficient of friction than many man-made shoes that allow easier traction to move forward for less energy expenditure. We also expanded our story to observe that the structure of the bones and major muscles attached to limbs for movements as lever systems provide higher speed and range of movements at the expense of exorbitant muscular efforts.

A most important knowledge for designing interfaces is a thorough recognition of the capabilities and limitations of the five senses.  One of the assignment involves comparing the various senses within two dozens categories such as: anatomy, physiology, receptor organs, stimulus, sources of energy, wave forms, reaction time, detectable wavelengths and frequencies, practical detection thresholds of signals, muscles, physical pressure, infections and inflammations, disorders and dysfunctions, assessment, diagnostic procedures, corrective measures, effects of age, and safety and risk.

Human dynamic efforts for doing mechanical work is at best 30% efficient because most of the efforts are converted to maintaining static positions in order to preserve stability and equilibrium for all the other concomitant stabilizing joints, bones and muscles.  For example, the stooping position consumes 60% of the efforts for having a work done, in addition to the extremely high moment effected on the edges of the lower back intervertebrae discs.  Static postures constrict the blood vessels and fresh blood is no longer carrying the necessary nutrients to sustain any effort for long duration and heart rate increases dramatically; lactic acid accumulates in the cells and fatigue ensues until the body rests in order to break down that acid.

Human energy efficiency is even worse because most of the energy expended is converted into heat.  Not only physical exercises generate heat but, except for glucose or sugar, most of the nutrients have to undergo chemical transformations to break down the compounds into useful and ready sources of energy, thus generating more heat.  Consequently, heat is produced even when sleeping when the body cells are regenerated. Internal heat could be a blessing in cold environments but a worst case scenario in a hot atmosphere because the cooling mechanism in human is solely confined to sweating off the heat accumulated in the blood stream.  Heat is a source of blessing when we are sick with microbes and bacteria because the latter is killed when the internal body temperature rises above normal.

Article #48, Started March 6, 2006

 “Efficiency of the human cognitive power or mind”

Cognitively, human is excellent in simple detection tasks or null indicator such as whether a sensation exist or not; he is fairly good in differentiating the direction of strength of a sensation such as bigger or smaller than a standard, but he is bad is evaluating whether a sensation is twice or three times stronger, and he is worst as a meter for exact measurements. Human is more accurate in feeling than when relying on his mind and that is why a subject is forced to make a choice between two stimuli rather than responding that the sensation between a standard and a variable stimulus is equally strong.

Man is not a good observer of complex events; even when viewers are forewarned that they are to see a movie about a crime and that that are to answer questions about details later the accuracy of the observers are very low.  Man is unable to be an objective recorder of the events that transpire because he gets involved in the scene actions.  Man has a very narrow range of attention and barely can satisfactorily attend to a couple of stimuli. This observation deficiency is compounded by our sensory differences and illusions; for example, one in sixteen is color blind, many suffer from tone deafness, taste blindness and so on.

Man does not think of himself objectively but rather has convictions, feelings, and explanations based on very restricted experiences, hearsays, memories and he tends to generalize and develop a set of beliefs concerning the operation of the mind.  Man usually expects to see and then see what he wants to see and hardly deviates from his beliefs and sometimes even when faced with facts.  Many scientists have overlooked obvious data because they clanged to their hypotheses and theories.  Man has to generate an abundance of reliable information and assimilate them before he could eliminate a few systematic biases that he acquired from previous generations and his personal experiences.

This lack of objectivity in human is referred to by the term “common sense”.   The fact is common sense ideas change and are undergoing continual revision mainly because of the results of research and controlled experimentations. For example, common sense says heavy objects cannot fly until airplanes are common realities; common sense says that human cannot see in the dark until infrared goggles have been tested; common sense says that it is laughable to use earplugs in order to hear people talking in very noisy backgrounds until it is experimented and proven to be correct.  The fact that your father or forerunners have always done something in a particular way does not prove that this is the best way of doing it.  The fact that famous people purchase a product from the best known firm does not permit the manufacturer to state that there cannot be very much wrong with the product since the famous people have bought it.




December 2020

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