• Proceedings of the Korea Society for Industrial Systems Conference
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• 1999.05a
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• pp.135-144
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• 1999

A major concern in Concurrent Engineering is the control and management of workload in a period of process. As a general rule, leveling the peak of workload in a certain period is difficult because concurrent processing is comprised of various processes, including overlapping, paralleling and looping. Therefore, workload management with resource constraints is so beneficial that effective methods to analyze design process This study presents a procedure to transform the IDEF3 process model into the precedence logic network model for more useful assessment of the process. This approach is expected to facilitate resolving resource constrained scheduling problems more systematically in Concurrent Engineering environment.

• Journal of the Ergonomics Society of Korea
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• v.24 no.3
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• pp.43-52
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• 2005

A two-dimensional posture measurement system was developed to evaluate the risks of work-related musculoskeletal disorders(MSDs) easily on various conditions of work. The posture measurement system is an essential tool to analyze the workload for preventing work-related musculoskeletal disorders. Although several posture measurement systems have been developed for workload assessment, some restrictions in industry still exist because of its difficulty on measuring work postures. In this study, an image recognition algorithm was developed based on a neural network method to measure work posture. Each joint angle of human body was automatically measured from the recognized images through the algorithm, and the measurement system makes it possible to evaluate the risks of work-related musculoskeletal disorders easily on various working conditions. The validation test on upper body postures was carried out to examine the accuracy of the measured joint angle data from the system, and the results showed good measuring performance for each joint angle. The differences between the joint angles measured directly and the angles measured by posture measurement software were not statistically significant. It is expected that the result help to properly estimate physical workload and can be used as a postural analysis system to evaluate the risk of work-related musculoskeletal disorders in industry.

• Journal of Korean Critical Care Nursing
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• v.10 no.1
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• pp.1-12
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• 2017

Purpose: This study aimed to estimate the appropriate nurse staffing ratio in intensive care units (ICUs) by measuring nursing workload based on patient's severity and needs, using the Korean Patient Classification System for critical care nurses. Methods: The data were collected from January 18 to February 29, 2016 using a standardized checklist by observation or self-report. During the study period, 723 patients were included to be categorized from I to IV using the patient classification system. Measurement of total nursing workload on a shift was calculated in terms of hours based on the time and motion method by using tools for surveying nursing activities. The nursing activities were categorized as direct nursing care, indirect nursing care, and personal time. Total of 127 cases were included in measuring direct nursing time and 18 nurses participated in measuring indirect and personal time. Data were analyzed using descriptive statistics. Results: Two patients were classified into Class I (11.1%), 5 into Class II (27.8%), 9 into Class III (50%), and two into Class IV (11.1%). The amount of direct nursing care required for Class IV (513.7 min) was significantly more than that required for Class I (135.4 min). Direct and indirect nursing care was provided more often during the day shift as compared to the evening or night shifts. These findings provided the rationale for determining the appropriate ratio for nursing staff per shift based on the nursing workload in each shift. Conclusions: An appropriate ratio of nurse staffing should be ensured in ICUs to re-arrange the workload of nurses to help them provide essential direct care for patients.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.261-262
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• 2018

The tasks of Vessel Traffic Services are classified according to the content of the information provided. Since the establishment of the first Vessel Traffic Service center in 1993 at Phohang harbour, it has been steadily developed and its work domain and scope have been expanded. In this paper, the importance and workload of Vessel Traffic Service operators were analyzed according to classification of the tasks. In order to measure the importance and workload, questionnaires were conducted for the operators nationwide, and conclusions were drawn using the multi-criteria decision making process. The relationship between the importance of tasks and the workload might be used as the weights for setting the service areas in the future. Furthermore, it is expected to be used as the data of changable sector operation based on the relationship between importance and workload.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.47-53
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• 2014

The application of advanced Main Control Room(MCR) is accompanied with lots of changes and different forms and features through the virtue of new digital technologies. The characteristics of these digital technologies and devices give many opportunities to the interface management, and can be integrated into a compact single workstation in advanced MCR so that workers can operate the plant with minimum physical burden under any operation conditions. However, these devices may introduce new types of human errors and thus a means to evaluate and prevent such errors is needed, especially those related to characteristics of digital devices. This paper reviewed the new type of human error hazards of tasks based on digital devices and surveyed researches on physiological assessment related to human error. An experiment was performed to verify human error hazards by physiological responses such as EEG which was measured to evaluate the cognitive workload of operators. And also, the performances of four tasks which are representative in human error hazard tasks based on digital devices were compared. Response time, ${\beta}$ power spectrum rate of each task by EEG, and mental workload by NASA-TLX were evaluated. In the results of the experiment, the rate of the ${\beta}$ power was increased in the task 1 and task 4 which are searching and navigating task and memory task of hierarchical information, respectively. In case of the mental workload, in most of evaluation items, task 1 and 4 were highly rated comparatively. In this paper, human error hazards might be identified by highly cognitive workload. Conclusively, it was concluded that the predictive method which is utilized in this paper and an experimental verification can be used to ensure the safety when applying the digital devices in Nuclear Power Plants (NPPs).

• Safety and Health at Work
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• v.10 no.3
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• pp.321-326
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• 2019

Background: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. Methods: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a $2{\times}2{\times}3$ within-subject repeated measures analysis of variance. Results: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. Conclusions: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1242-1242
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• 2022

Annually, several construction workers fall ill, are injured, or die due to heat-related exposure. The prevalence of work-related heat illness may rise and become an issue for workers operating in temperate climates, given the increase in frequency and intensity of heatwaves in the US. An increase in temperature negatively impacts physical exertion levels and mental state, thereby increasing the potential of accidents on the job site. To reduce the impact of heat stress on workers, it is critical to develop and implement measures for monitoring physical exertion levels and mental state in hot conditions. For this, limited studies have evaluated the utility of wearable biosensors in measuring physical exertion and mental workload in hot conditions. In addition, most studies focus solely on male participants, with little to no reference to female workers who may be exposed to greater heat stress risk. Therefore, this study aims to develop a process for objective and continuous assessment of worker physical exertion and mental workload using wearable biosensors. Physiological data were collected from eight (four male and four female) participants performing a simulated drilling task at 92oF and about 50% humidity level. After removing signal artifacts from the data using multiple filtering processes, the data was compared to a perceived muscle exertion scale and mental workload scale. Results indicate that biosensors' features can effectively detect the change in worker physical and mental state in hot conditions. Therefore, wearable biosensors provide a feasible and effective opportunity to continuously assess worker physical exertion and mental workload.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.2
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• pp.173-180
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• 2014

In this paper, the instrument flight certification process and flight test results of Korean Utility Helicopter (KUH) are presented. For the instrument flight certification, the suitability of installed equipments and instruments have been reviewed and verified by ground and flight tests. Next, static and dynamic stability test are conducted in accordance with FAR-29 Appendix B. The static stability is determined by the change of speed and attitude according to control inputs. The dynamic stability is evaluated by how quickly the response of the helicopter due to long and short period control inputs are decreased. The pilot workload evaluation are also carried out by simulated IMC flight tests. This paper presents the workload assessment results when some failures are occurred at cockpit instruments, engine or flight control systems as well as the normal situation. After the simulated IMC flight test is completed, actual instrument flight test are conducted in a real IMC environment according to the air traffic controls.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.2
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• pp.73-80
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• 1999

A major concern in Concurrent Engineering is the control and management of workload As a general rule, leveling the peak of workload in a period is difficult because concurrent processing is comprised of various processed, including overlapping, paralleling and looping and so on. Therefore workload management with resource constraints is so beneficial that effective methods to analyze design process are momentous. This paper presents a procedure to transform the IDEF3 process model into the precedence network model for more useful assessment of the process. This procedure is expected to facilitate resolving resource constrained scheduling problems more systematically in Concurrent Engineering environment.

• Nuclear Engineering and Technology
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• v.36 no.1
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• pp.64-72
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• 2004

The purpose of this study is to develop a system dynamics model for the assessment of the organizational and human factors in a nuclear power plant which contribute to nuclear safety. Previous studies can be classified into two major approaches. One is the engineering approach using tools such as ergonomics and Probability Safety Assessment (PSA). The other is the socio-psychology approach. Both have contributed to find organizational and human factors and to present guidelines to lessen human error in plants. However, since these approaches assume that the relationship among factors is independent they do not explain the interactions among the factors or variables in Nuclear Power Plants. To overcome these restrictions, a system dynamics model, which can show cause and effect relationships among factors and quantify the organizational and human factors, has been developed. Handling variables such as the degree of leadership, the number of employees, and workload in each department, users can simulate various situations in nuclear power plant organization. Through simulation, users can get insights to improve safety in plants and to find managerial tools in both organizational and human factors.