Adonis Diaries

Posts Tagged ‘maintainability

Human Factors in Engineering (Article #43)

“Controlled experimentation versus Evaluation and Testing methods”

The methods of evaluation and testing are basically subset of controlled experimentation: They differ on the purpose, the types of relevant variables, the level of control, and the logical and chronological phase in a scientific study.

Usually, any scientific undertaking need a theoretical model, the variables and procedures are extracted from exploratory studies, earlier research, and observations that might discover analogies with other more developed concepts.

The next phase is to conduct varied controlled experimentations in artificial settings for repeatability by other researchers with the purpose of generating the main factors/independent variables that have significant effects on the behavior of the selected and valid dependent variables.

The results of controlled experimentations may be used to either validate/modify a theoretical model that could offer explanations for the behavior/concept under study, or provide practical design guidelines for manufacturing efficient products/processes or developing systems such as educational, training, or safety programs.

The logical next phase is to test the theoretical model, product, or system in a real world context or real life setting in order to validate the extent of its effective performance when operated by target users.  Consequently, the purpose of testing is to study the effectiveness of the specifications of the product when applied in a real life setting so that further modifications and redesigns are undertaken; the question is: “Does the product/system actually works? Does it deliver as claimed?”  

Testing methods are the debugging procedures; The logical criteria/dependent variables are the type of errors, malfunction, dysfunctional mismatch with operators’ skills, number of errors, seriousness of errors, probability distribution of occurrence of defects, and training time required. The independent variables/factors are the comparisons among the kind of real world settings, types of operators, sort of idiosyncrasies, and the processes.

The final phase is the evaluation among competing products/systems to enable management deciding on the better choice on the market that satisfy its requirements.

The question is: “Can the product/system be accepted, acquired, and purchased?” 

What is compared is not just the product but the whole package that comes with it; mainly, the added features, the instruction manuals, audio-visual training programs, maintainability, availability of spare parts, client-marketing responses to claims, malfunctions, misuses, plaintiffs’ cases in product liability, and on time delivery.

Although the final output of an evaluation is the decision of management of (Yes/No), there are a prior output for rating the various specifications with relative weights attached to each factor and thus, the evaluation method is a series of evaluations for each specification that differ in the level of control and objectivity and measurement accuracy of the responses.

For example, in comparing warning alarm systems, management might want a system that forces all workers to vacate within standard safety duration and within an acceptable frequency of false warning activation.

Any additional features such as visual feedback in police cars, possibility of connecting to a central fire station, and regular maintenance can tip the balance toward a product that was as performing as others.

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 #43,  April 12, 2006

“Controlled experimentation versus Evaluation and Testing methods”

The methods of evaluation and testing are basically subset of controlled experimentation but differ on the purpose, the types of relevant variables, the level of control, and the logical and chronological phase in a scientific study.  Usually, any scientific undertaking need a theoretical model extracted from exploratory studies, earlier research, and observations that might discover analogies with other more developed concepts. 

The next phase is to conduct varied controlled experimentations in artificial settings for repeatability by other researchers with the purpose of generating the main factors/independent variables that have significant effects on the behavior of the selected and valid dependent variables.  The results of controlled experimentations may be used to either validate/modify a theoretical model that could offer explanations for the behavior/concept under study, or provide practical design guidelines for manufacturing efficient products/processes or developing systems such as educational, training, or safety programs.

The logical next phase is to test the theoretical model, product, or system in a real world context or real life setting in order to validate the extent of its effective performance when operated by target users.  Consequently, the purpose of testing is to study the effectiveness of the specifications of the product when applied in a real life setting so that further modifications and redesigns are undertaken; the question is: “Does the product/system actually works? Does it deliver as claimed?”   Testing methods are the debugging procedures and the logical criteria/dependent variables are the type of errors, malfunction, dysfunctional mismatch with operators’ skills, number of errors, seriousness of errors, probability distribution of occurrence of defects, and training time required. The independent variables/factors are the comparisons among the kind of real world settings, types of operators, sort of idiosyncrasies, and the processes.

The final phase is the evaluation among competing products/systems to enable management deciding on the better choice on the market that satisfy its requirements. The question is: “Can the product/system be accepted, acquired, and purchased?”  What is compared is not just the product but the whole package that comes with it; mainly, the added features, the instruction manuals, audio-visual training programs, maintainability, availability of spare parts, client-marketing responses to claims, malfunctions, misuses, plaintiffs’ cases in product liability, and on time delivery.  Although the final output of an evaluation is the decision of management of (Yes/No), there are a prior output rating the various specifications with relative weights attached to each factor and thus the evaluation method is a series of evaluations for each specification that differ in the level of control and objectivity and measurement accuracy of the responses. For example, in comparing warning alarm systems, management might want a system that forces all workers to vacate within standard safety duration and within an acceptable frequency of false warning activation.  Any additional features such as visual feedback in police cars, possibility of connecting to a central fire station, and regular maintenance can tip the balance toward a product that was as performing as others. 


adonis49

adonis49

adonis49

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