• Journal of the Korea Society for Simulation
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• v.12 no.1
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• pp.21-34
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• 2003

This paper deals with a case study of workload analysis of an operator in an automatic line for machining the race of ball bearing. Eleven machines and three hoppers are installed in the line which is operated by an operator. The elements of operation are separated into machine controlled elements, operator controlled elements and machine/operator controlled elements. In order to analyze the system, time and motion studies are used for gathering input data for the simulation model. The first objective of this study is to evaluate whether the workload of operator is reasonable or not. The second objective is to increase throughput by reducing tact time and the last one is to increase frequencies of inspection by reducing interval. Thus we suggest some ideas for improvement, and as a result, the throughput is improved about 9%. In spite of the increasing of throughput, the allowance of operator is also increased about 4%.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.2
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• pp.178-186
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• 2002

The objective of this study is to evaluate impact of computer-based man-machine interfaces of Korea Next Generation Reactor (KNGR) on the operator mental workload. Empirical experiments were conducted to measure the operator mental workloads of KNGR and Yong-Gwang Unit 3 and 4, respectively. A comparison analysis based on a NASA TLX revealed that Yong-Gwang Unit 3 and 4 were superior to KNGR in terms of the mental workload. Post-hoc analyses showed that the mental workload of senior reactor operators was significantly higher than those of reactor and turbine operators, regardless of plant types. The implications of the findings were discussed in detail.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.1
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• pp.54-65
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• 2000

The objective of this study is to evaluate the operator performance relating to hand switches with two or three buttons in the main control rooms of nuclear power plants. Based on the comparative analysis of the nuclear power plants, two different subjective workload-rating scales were used to evaluate the performance of 48 operators: the Overall Workload(OW) and National Aeronautics and Space Administration Task Load Index (NASA TLX). The survey questions consisting of the eight-items were asked to evaluate the operating experiences for the two different switch types. The OW scales ratings were applied to measure the workload of the switch-related tasks. The ratings revealed that signal detection tasks caused less workload in the three-buttoned-switch operators than the other switch group. However, in the switch operation tasks, the switch types did not show statistically significant effects on workload level. The NASA TLX scale ratings were performed based on detailed task scenarios that assumed the accident of small break loss of coolant, what we call, the small LOCH. The NASA TLX was administered to three different task groups: the reactor, the turbine, and the electric operator groups. Based on the NASA TLX, the two-buttoned switch groups showed higher workload than those with the three-buttoned switches. However, a statistically significant difference was found only in the reactor operator groups. When the current switch type was assumed to be changed for the other type, all of the three-buttoned switch groups were predicted to have higher workload than the other switch groups, respectively. The implications of these findings were discussed.

• The Journal of Korea Robotics Society
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• v.13 no.3
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• pp.151-156
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• 2018

Military robots are expected to play an important role in the future battlefield, and will be actively engaged in dangerous, repetitive and difficult tasks. During the robots perform the tasks a human operator controls the robots in a supervisory way. The operator recognizes battlefield situations from remote robots through an interface of the operator control center, and controls them. In the meantime, operator workload, controller interface, robot automation level, and task complexity affect robot operability. In order to assess the robot operability, we have developed ROSim (Robot Operational Simulator) incorporating these operational factors. In this paper, we introduce the results of applying ROSim experimentally to the assessment of reconnaissance robot operability in a battle field. This experimental assessment shows three resulting measurements: operational control workload, operational control capability, mission success rate, and discuss its applicability to the defense robot research and development. It is expected that ROSim can contribute to the design of an operator control center and the design analysis of a human-robot team in the defense robot research and development.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.615-621
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• 2014

VTS operators may suffer from acute, chronic, or traumatic stress caused by their workload and working environments associated with task or combination of task. This study intended to measure the level of VTS operator' stress and find out factors influencing it by understanding their characteristics during carrying out their task. For this purpose, analyzed the data collected through conducting survey on VTS operators as the Korea Occupational Stress(KOSS) and Psychological Well-being Index(PWI). As a result, VTS operators are experiencing higher level of psychological stress than the national average. And the factors to cause VTS operators' occupational stress can be summarized as follows; working environment factors, shift work especially night duty, workload, etc. This study provides the fundamental information for understanding human factors of VTS operator' occupational stress.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.284-291
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• 2017

There is no doubt that advances in UAV technology have improved military performance. However, these advances require humans to adapt to new and complex operational systems. UAV has been rapidly expanding to a variety of fields such as reconnaissance, transportation, communication and aerial photographing recently. Also, with the development of UAV automation technology, one operator is able to supervisory-control multiple-UAVs. However, as the number of assigned UAV increases, the amount of information increases and this results in the workload of the operator increasing and deterioration in controlling performance. Accordingly, there is a need for a model to determine the level of overload an operator may encounter with regard to multiple-UAV but nationally this kind of research is currently lacking. Therefore, this paper provides an experimental platform for evaluating workload index effectiveness integrating multiple-UAV operational environments, GCS, and eye-tracking system followed by a limited survey of domestic and international studies of multi-UAV overload studies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.61
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• pp.23-31
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• 2000

This paper addresses the static operator allocation problem in celluar manufacturing systems(CMS). An assembly environment is considered where each component going into the final product is manufactured in an individual cell. There are m such cells and it is required to manufacture n varieties of products where n>m. An mathematical model and two heuristic algorithms for static operators allocation to the cells to balance workload for minimizing makespan are developed and tested.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.579-580
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• 2004

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4147-4157
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• 2015

The weapon system has developed by adding various functions because of the warfare change. And, an weapon system test set (WSTS) that is used to test and judge the condition of weapon system also deal with a lot of complex information. However, almost WSTS is developed on the basis of developer-centric. Because of it, it is hard to make a result by apprehending information on WSTS's display. Thus, I proposed a new display of WSTS by adapting the Ecological Interface Design(EID) Methodology to reduce operator's cognitive workload and assure safe testing. WSTS's Display is developed through Information Requirement and Work Domain Model as a result of Work Domain Analysis. The most powerful thing in the new display is that operator can identify his testing and status of WSTS directly. I expect that it reduces operator's cognitive workload and helps safe testing.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.57-68
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• 1998

Work environments have been changed with the advent of new technologies, such as computer technology. However, human cognitive limits can't pace up with the change of work environment. Designing human-computer system requires knowledge and evaluation of the human cognitive processes which control information flow workload. Futhermore, under limited reaction time and/or urgent situation, human operator may the work stress, work error and resultant deleterious work environment. This paper evaluate the visual factors of major information processing factors(information density, amount of information, operational speed of speed)on operator performance of supervisory control under urgent(limited reaction time)environments which require deleterious work condition. To describe the work performance int the urgent work situations with time stress and dynamic event occurrence, a new concept of information density was introduced. For a series of experiments performed for this study, three independent variables(information amount, system proceeding speed, information density) were evaluated using five dependent variables. The result of statistical analyses indicate that the amount of information affected on all of five dependent measure. Number of failure and number of secondary task score were influenced by both amount of information and operational speed of system. However reaction time of secondary task were affected by both amount of information and information density. As a result, the deleterious factors for the performances seemed to be a scanning time to supervise each control panel. Consequently, a new display panel was suggest to reduce operator work load for scanning task showing better operator performance.