• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.359-370
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• 2022

Objective: This study is intended to design a commercially available passive sampler and conduct performance test on its use as a media for evaluating a working environment. Methods: This study was conducted to select adsorbents, design models, and evaluate storage stability and sampling rates for the development of new types of passive samplers. Results: The impurity detection, adsorbent capacity and breakthrough volume of five types of activated carbon were tested for selection of an adsorbent. One product was selected in consideration of the efficiency of purchase. A number of passive samplers were designed in a radial style and a badge style using plastic as a material. The final two prototypes were made using molds or 3D printing. For the storage stability evaluation, samples were stored at different temperature for 1~21 days and then analyzed. Most of the chemicals had excellent storage stability when refrigerated. However, some chemicals such as dichloromethane and methyl ethyl ketone need to be analyzed as soon as possible after sampling. Conclusion: In this study, new types of passive samplers for 66 chemical compounds were developed. The evaluation of storage stability and sampling rates showed different results depending on the properties of the chemical substance. For some chemicals such as methyl ethyl ketone and dimethylformamide, activated carbon is inappropriate as an absorbent. In future studies, additional experiments are required on chemicals that are difficult to collect with activated carbon.

• Journal of the Korean Society of Safety
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• v.29 no.6
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• pp.49-54
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• 2014

Electrostatic eliminators are essential in various areas of manufacturing industries to protect electrostatic hazards and to reduce inferior products. For ion sources used in the charge neutralizers, there are corona discharge, soft X-ray, and ultraviolet and glow discharge. Among them, corona discharge is generally used, because the corona discharge can easily and economically produce positive and negative ions including electrons in air at atmospheric pressure. But it is necessary to equip explosion-protection electrostatic eliminators wherever hazardous atmosphere. The electrostatic eliminators and their testing method of explosion-protection type have been developed in this research. The contents and scope of the research as follows; developing the type 'Ex s IIB T4' electrostatic eliminator of explosion-protection; developing the type 'Ex s d IIB T4' electrostatic eliminator of explosion-protection; developing the explosion-protection performance testing method of electrostatic eliminator for using AC power source.

• Safety and Health at Work
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• v.3 no.3
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• pp.192-198
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• 2012

Objectives: Slip and fall accidents in the workplace are one of the top causes of work related fatalities and injuries. Previous studies have indicated that fall risk was related to postural and dynamic stability. However, the usage of this theoretical relationship was limited by laboratory based measuring instruments. The current study proposed a new method for stability assessment by use of inertial measurement units (IMUs). Methods: Accelerations at different body parts were recorded by the IMUs. Postural and local dynamic stability was assessed from these measures and compared with that computed from the traditional method. Results: The results demonstrated: 1) significant differences between fall prone and healthy groups in IMU assessed dynamic stability; and 2) better power of discrimination with multi stability index assessed by IMUs. Conclusion: The findings can be utilized in the design of a portable screening or monitoring tool for fall risk assessment in various industrial settings.

• Safety and Health at Work
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• v.8 no.2
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• pp.226-230
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• 2017

The performance of sound barriers was evaluated to determine their technical effectiveness and practicality in reducing noise exposures to operating engineers in construction. Commercially purchased sound dampening mats (SDMats) were installed inside three heavy-equipment engine compartments. Sound pressure levels (SPLs) were measured before and after installing the SDMats while the equipment was on idle and full-throttle settings where it normally operates. SPLs inside the heavy-equipment operator cabs were significantly reduced by 5.6-7.6 dBA on the full-throttle setting following installation of the SDMats (p < 0.01). The evaluated engineering control intervention was simple to install, affordable, and substantially reduced the engine noise reaching the heavy-equipment operator, potentially reducing reliance on hearing-protection devices to protect construction workers from noise exposures.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.232-233
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• 2010

This paper investigates occupational exposure to time-varying magnetic field generation in high power rectifier systems. Two different kinds of high power rectifier systems of 25kA are modeled and analyzed. The performance is compared and evaluated on the basis of exposure guidelines from ICNIRP. In order to focus on the qualitative effect of rectifier operation, the mechanical structure of current carrying conductors is simplified as infinite long bus-bar model and low frequency harmonic contents up to 65kHz are considered. Thyristor rectifier generates a significant amount of low frequency magnetic field harmonic contents both at ac and dc side of rectifier infringing the limit from ICNIRP. The multilevel rectifier-IGCT type has almost negligible field generation from ac input side and smaller harmonic contents in dc load side complying with ICNIRP guideline. This remarkable advantage of multilevel rectifier-IGCT type can lead to very simple site layout design for installation and cost-effective compliance to guideline of occupational exposure against magnetic field.

• Journal of the Korea Safety Management & Science
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• v.4 no.3
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• pp.13-23
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• 2002

The use of industrial robots has been one of the most important innovations in production technology in recent years. It is true that robotic techniques, as applied to hazardous operation in industry, have reduced the risk of injury and occupational disease among workers. However, new types of occupational safety and health risks, associated with unpredictable motion patterns and erratic idle times and serious injuries and deaths have occurred due to operator misperception of these robot design and performance characteristics. This paper provides an overview of ergonomic and safety issues which are important in the design of robotic workspaces. Particularly, this study uses MORT(Management oversight and risk tree analysis)as the system's safety technique applied to robotics.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.18-24
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• 2022

This study attempts to provide basic data for the development of manpower maintenance programs by checking the degree of job stress and emotional burnout for nurses working in a university hospital and identifying factors affecting emotional burnout. Data were obtained through a structured questionnaire survey conducted on 187 nurses. The average score for job stress of nurses was 2.50 (range 1 to 4) and emotional burnout was 3.29 (range 1 to 5). The factors affecting emotional burnout were occupational climate, job demand, job insecurity, and lack of reward, which accounted for 44% of explanatory power. In order to reduce the emotional burnout of nurses, the management of medical institutions needs administrative and financial support. Further, it is necessary to improve the organizational culture regarding job assignment through job analysis, employment security, and a performance-based reward system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.40-41
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• 2021

The construction industry has the highest occupational accidents/injuries among all industries. Korean government installed surveillance camera systems at construction sites to reduce occupational accident rates. Construction safety managers are monitoring potential hazards at the sites through surveillance system; however, the human capability of monitoring surveillance system with their own eyes has critical issues. Therefore, this study proposed to build a deep learning-based safety monitoring system that can obtain information on the recognition, location, identification of workers and heavy equipment in the construction sites by applying multiple-object tracking with instance segmentation. To evaluate the system's performance, we utilized the MS COCO and MOT challenge metrics. These results present that it is optimal for efficiently automating monitoring surveillance system task at construction sites.

• Physical Therapy Rehabilitation Science
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• v.5 no.2
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• pp.63-69
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• 2016

Objective: To evaluate the effects of sit-to-stand (STS) imagery group training (IGT) on STS movement and balance performance for chronic hemiparetic stroke. Design: Randomized controlled trial. Methods: A total of 30 people with chronic hemiparetic stroke (15 for STS-IGT group and 15 for control) were recruited in this study. The STS-IGT group participated in a videotape-based STS-IGT for 30 minutes a day, five days a week for six weeks, while the control group watched a documentary on television for the same period. The STS-IGT focused on a five-stage protocol. Specifically, external imagery was used during the four phases of the STS movement from the seat of the chair to standing up. All of the participants also participated in a regular rehabilitation program. STS movement and balance performance were assessed using three clinical measures. Results: After training, time to perform the 5-repetition STS test significantly increased in the STS-IGT group (change value, $4.0{\pm}2.0$ sec) compared with the control group (change value, $0.9{\pm}0.7$ sec) (p<0.05). There was a greater improvement in Berg balance scale scores in the STS-IGT group (change value, $0.2{\pm}4.1$ points) compared with the control group (change value, $0.3{\pm}0.9$ points) (p<0.05). There was a greater improvement in Timed Up and Go scores in the STS-IGT group (change value, $2.6{\pm}1.5$ sec) compared with the control group (change value, $0.9{\pm}1.0$ sec) (p<0.05). Conclusions: STS-IGT can be considered as a useful option for restoration of STS movement and balance performance for individuals with chronic hemiparetic stroke who are unable to fully participate in physical activities.

• Safety and Health at Work
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• v.8 no.2
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• pp.189-197
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• 2017

Background: Despite the recent efforts to prevent industrial accidents in the Republic of Korea, the industrial accident rate has not improved much. Industrial safety policies and safety management are also known to be inefficient. This study focused on dynamic characteristics of industrial safety systems and their effects on safety performance in the Republic of Korea. Such dynamic characteristics are particularly important for restructuring of the industrial safety system. Methods: The effects of damping and elastic characteristics of the industrial safety system model on safety performance were examined and feedback control performance was explained in view of cost and benefit. The implications on safety policies of restructuring the industrial safety system were also explored. Results: A strong correlation between the safety budget and the industrial accident rate enabled modeling of an industrial safety system with these variables as the input and the output, respectively. A more effective and efficient industrial safety system could be realized by having weaker elastic characteristics and stronger damping characteristics in it. A substantial decrease in total social cost is expected as the industrial safety system is restructured accordingly. Conclusion: A simple feedback control with proportional-integral action is effective in prevention of industrial accidents. Securing a lower level of elastic industrial accident-driving energy appears to have dominant effects on the control performance compared with the damping effort to dissipate such energy. More attention needs to be directed towards physical and social feedbacks that have prolonged cumulative effects. Suggestions for further improvement of the safety system including physical and social feedbacks are also made.