Operator-Machine Systems

Once potential ergonomic problems have been recognized and superficially evaluated for specific jobs or locations, the operator-machine system is used to categorize major conditions contributing to ergonomic problems. Operator-machine system analysis examines 

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Human Factors—a discipline concerned with designing machines, operations, and work environments so that they match human capabilities, limitations, and needs. Includes any technical work (engineering, procedure writing, worker training, worker selection, and other items) related to the human factor in operator-machine systems. 

List and describe the components of the Operator-Machine System... 

Psychosocial factors, the third element of the people component of the operator-machine system, refers to an individual s behavior in a group environment. The term psychosocial is derived from the phrase social psychology. The ergonomist is interested in attitude formation, attitude change, leadership styles, power and influence, conflict, occupational stress, organizational structure, employee motivation, and organizational reward systems. All can influence... 

What are the components of the operator-machine system Provide an example of a work activity using this system. 

The cutting tool is an important component of the machining system. Consequendy, tool materials significantly affect machining operation productivity. Other elements include cutting conditions, tool geometry, and the characteristics of the work material, nature of parts produced, machine tool, and support system. 

It kg Avg Instant oz gr Package setup, supply FiUing- machine operators Package closers PaUetizers, loaders, attendants Package conveyorized Automatic palletizing Filling machine System ... 

Gertman, D. I., Haney, L. N., Jeirkins, J. P., Blackman, H. S. (1985). Operator Decision Making Under Stress. In G. Johannsen, G. Mancini, L. Martensson (Eds.). Analysis Design and Evaluation of Man-Machine Systems (Proceedings of the 2nd IFAC/IFIP/IFORS Conference, Varese, Italy). 

Risk Homeostasis The theory that an operator will attempt to maintain a stable perception of risk following the implementation of new technology that increases the safety of a human-machine system. The theory predicts that operators will take greater risks where more safety devices are incorporated into the system. 

Low-limit alert The first alert (i.e., low-limit alerta) should be set at the lowest vibration amplitude that will be encountered from a normally operating machine-train. This value is needed to ensure that valid data are taken with the microprocessor. If this minimum amplitude is not reached, the system alerts the operator, who can retake or verify the data point. Low-limit selection is arbitrary, but should be set slightly above the noise floor of the specific microprocessor used to acquire data. 

Ackoff and Sasieni [1] defined operations research (OR) as the application of scientific method by interdisciplinary teams to problems involving the control of organized (man-machine) systems so as to provide solutions which best serve the purposes of the organization as a whole . 

Based on the demonstration funded by the U.S. Environmental Protection Agency in Frederick, Maryland, the vendor estimated the costs associated with building and maintaining a Living Machine for the treatment of municipal wastewater. Table 1 displays the capital costs for Living Machine systems that process 40,000 gal per day (gpd), 80,000 gpd, and 1,000,000 gpd. The operations and maintenance costs for the systems are shown in Table 2. Table 3 demonstrates the total annual costs for the systems (D22581K, pp. 13-9-13-13). 

As technology progresses the safety of man-machine systems depends more and more on the quality of the human component (operator). This fact is very obvious in transportation, where the operator (driver) is formally and actually in control of his or her vehicle. In aviation, however, a strong trend towards software control of the aeroplane is already becoming dominant, forcing the operator (pilot) primarily into the role of supervisor or monitor of the automatic control system and into that of trouble-shooter in case of (technical) failure. In this respect a cockpit crew is facing the same situation as for instance a shift of operators in the central control room of a completely computerised chemical process plant. 

After the furnish has been prepared with the proper refining treatment and additives, it is stored in the machine chest and then fed continuously into the paper machine system. A refiner or jordan is placed in this line to give the paper machine operators the opportunity to make small adjustments in the quality of the furnish as needed to give the desired paper properties. Screens and centrifugal cleaners also are included to ensure a high-quality paper. 

The ion pump is widely used in all-metal systems, which are usually fabricated of stainless steel with copper gaskets between machined stainless-steel flanges. With the ion pump in operation, these systems can be baked out for several hours at 250°C (or even as high as 400°C) to desorb surface gases (mainly water). The ion pump can be baked out at the same time, but its temperature should not exceed 250°C (to protect the magnet). 

The important characteristic for HHM efficiency is the alloy output, i.e. the heat capacity related to weight of hydride alloy. The value achieved for today on the average for a cycle makes 40-100 W/kg. At shortening of a cycle this value grows, but up to achievement of competitive (in comparison with other heat machines of similar type) value in 1000 W/kg [8] are necessary for increasing cardinally amount of active hydrogen, to increase effective heat conductivity of a hydride bed and to optimize operation of system a sorber-heat exchanger. Thus duration of a hill cycle is estimated 2-4 minutes. 

Lubrication by Transfer from a Reservoir is the most important practical application of transfer, as it provides a means for continually supplying molybdenum disulphide to a machine system during operation. 

The potential for computer attack against an automated system or conflicts between poorly coordinated operations arises from allowing connection to remote machines. An attack can be resisted by operating the system on an independent network with no possible connection from unauthorized parties. Use of public infrastructure, such as public voice or data networks is more cost-effective, but open to mischievous or malicious attack. 

Similarly, skill-based pay systems reward employees for their breadth of knowledge pertaining to different jobs (e.g., proficiency in a number of various production jobs). For instance, if one person could operate machines A, B, and C, she may be paid 15 per hour (even if she only works on machine A all year). Her colleague may be qualified to work on machines A and C, and therefore he would only make 13 per hour (even if he worked on both machines over the course of the year). As can be seen, pay is driven by the quantity of tasks a person is qualified to perform. 

In any sampling, we must define the unit of sampling, the sampling frame, and the sample choice technique. For a human factors audit the unit of sampling is not as self-evident as it appears. From a job-evaluation viewpoint (e.g., McCormick 1979), the natural unit is the job that is composed of a number of tasks. From a medical viewpoint the unit would be the individual. Human factors studies focus on the task/operator/machine/environment (TOME) system (Drury 1992) or equivalently the software/hardware/environment/Uveware (SHEL) system (ICAO 1989). Thus, from a strictly human factors viewpoint, the specific combination of TOME can become the sampling unit for an audit program. 

In a two-year project, reported by Simpson (1994) and Fox (1992), the human error audit described in Section 3.2 was applied to two colliery haulage systems. The results of the first study will be presented here. In both systems, data collection focused on potential errors and the performanceshaping factors (PSFs) that can influence these errors. Data was collected by observation, discussion and measurement within the firamework of the broader man-machine systems and checklist of PSFs, taking some 30-40 shifts at each site. The whole haulage system from surface operations to delivery at the coal face was covered. 

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