• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.379-386
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• 2012

The aim of this study was to investigate and identify the differences in lower extremity energy dissipation strategies between drop-landing and countermovement-jump maneuvers. Fourteen recreational athletes(Age : $23.3{\pm}2.1years$, Height : $172.3{\pm}4.0cm$, Weight : $69.2{\pm}4.7kg$) were recruited and instructed to perform drop-landing from 45 cm height and countermovement-jump from 45 cm to 20 cm height. The landing phase was taken as the time between initial contact and peak knee flexion. A motion-capture system consisting of eight infra-red cameras was employed to collect kinematics data at a sampling rate of 200 Hz and a force-plate was used to collect GRF data at a sampling rate of 2000 Hz. Paired t-test was performed to determine the difference in kinematics and kinetics variables between each task. During the countermovement-jump task, all of lower extremity joint ROM and the hip joint eccentric moment were decreased and the ankle joint plantarflexion moment was increased than drop-landing task. In the eccentric work during countermovement-jump task, the ankle joint displayed greater while knee and hip joint showed lesser than drop-landing. Therefore, the knee joint acted as the key energy dissipater during drop-landing while the ankle joint contributed the most energy dissipation during countermovement-jump. Our findings collectively indicated that different energy dissipation strategies were adopted for drop-landing and countermovement-jump.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.11
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• pp.854-860
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• 2014

Workers engaged in car inspection works have been exposed to many occupational hazards including noise, particulate matter, and volatile organic substances. Noise-induced hearing loss(NIHL) is one of the leading health hazards among Korean workers. The aim of this study is to evaluate the noise levels in several car inspection shops by introducing the evaluation methods of KMOEL/OSHA and ACGIH. Six sites in central area of Korea were selected to monitor the noise levels of workers by personal and area sampling methods for two consecutive days in spring, summer, fall and winter seasons. Dosimeters have been used for this noise monitoring program. Obtained noise levels by the evaluation method according to KMOEL/OSHA are the range of 50.2~88.2 dB(A), these are lower than KOEL/OSHA standards level of 90 dB(A). But highest noise by ACGIH's evaluation methodology is recorded 92.3 dB(A) and is greater than NIHL standard level of 85 dB(A). So that many workers may be exposed to the dangerous noise environment. The higher the car inspection loads daily, the higher the noise levels in the sites. Seasonal fluctuation of noise levels at the process might give monitoring results with high variations. Area noise levels showed higher than those of personal sampling, which illustrate some high noise spots in the car inspection areas.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.3
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• pp.266-273
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• 2021

Objective: The objective of this study was to suggest improvement methods for investigations and systems through a review of musculoskeletal risk factor investigation reports conducted in the workplace. Methods: A total of 34 reports on musculoskeletal risk factor investigations were reviewed. To confirm the appropriateness of the evaluation, reevaluation was conducted through a field investigation using other evaluation tools. In order to understand the effectiveness of the improvement plan, a survey was conducted with those in charge of tasks with ergonomic burdens. Results: As a result of performing a field survey using the work sampling method recommended by the KOSHA (Korea Occupational Safety and Health Agency) for ten tasks, eight tasks were determined to pose an ergonomic burden. When 30 tasks were evaluated with RULA (rapid entire body assessment), 90% of them were evaluated at a higher level than the results of the workplace survey. Among the improvement measures, only 36% of the field workers affirmed them, and in only 19% of the workplaces were actual improvements made. Conclusions: In order to improve the ergonomic investigation system for risk factors in the ergonomic burden task, it is necessary to secure the objectivity of the evaluation performed by the institution and enable the active participation of workers in improvement activities.

• Korean Journal of Applied Biomechanics
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• v.33 no.1
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• pp.1-9
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• 2023

Objective: This study identifies the difference among the heights of a chair's backrest (High, Mid, No), the biomechanical changes chair users undergo over time, and the variables that can measure musculoskeletal disorders, eventually providing information on the appropriate type of backrest. Method: Eleven healthy subjects in their 20s and 30s who had no experience with musculoskeletal disorders or surgical operations within the last 6 months participated in this study. Computer typing tasks were randomly designated and performed according to the type of chair backrest, and evaluation was performed for Flexion-Relaxation Ratio (FRR) analysis after the computer typing tasks. This study used eight infrared cameras (sampling rate: 100 Hz) and nine-channel electromyography (sampling rate: 1,000 Hz). ANOVA with repeated measures was conducted to verify the results, with the statistical significance level being α = .05. Results: Although there was no significant difference in craniovertebral angle (CVA), this study showed time and interaction effects depending on the height of the backrest (p<.05). When working without the backrest, the head-spine angle was lower compared to the chairs with backrest, based on the computer work. As for the head angle, the higher the back of the chair was, the less the head flexion and the body angle became, whereas the body flexion became less when there was a backrest. In addition, the body flexion increased over time in all types of backrests (p<.05). The muscle activity of the upper body tended to be high in the high backrest chair. On the other hand, a lower muscle activity was found with a low backrest. Conclusion: These results show that a chair is more ergonomic when the body angle is correctly set without bending and when it is supported by a low backrest. Accordingly, this study determines that the backrest affects shoulder and neck musculoskeletal disorders during typing and that medium-height backrest chairs can help prevent musculoskeletal disorders, contrary to the expectation that high-backrest chairs are preferable.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.2
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• pp.31-46
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• 2016

The purpose of this study is to examine the effects of human touch on turnover intention of ground handling employees at airport. Additionally, this study examines a comprehensive mediating effect of the work schedule and workload between human touch and turnover intention. To examine them, over 700 ground handling employees from six international airports of South Korea were surveyed using the simple random sampling method. The instrument for data collection was a questionnaire, and it was developed based on previous research results. The methodology adopted in this study is the structural equation modeling (SEM). According to SEM analysis, it was proven that both psychological and physical human touch have a significant effect on turnover intention of the employees. Work schedule played a mediating role among all three factors of human touch and turnover intention. However, workload has a mediating effect only between communication human touch and turnover intention. Based on the above findings, theoretical and practical implications are also discussed.

• Korean Parent-Child Health Journal
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• v.13 no.1
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• pp.17-25
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• 2010

Purpose: This study was conducted to investigate the recognition on center-based child care health programs for parents with ill children. Methods: Cross-sectional descriptive study with convenient sampling method was used and 136 parents were recruited from two university hospital outpatient departments and hospitalized wards, and they completed a structured questionnaire. Results: Majority (57.4%) of parents experienced a leaving work early or being absent from their work due to children's illness. Most dissatisfying factors in child care centers were child health management. Most of parents agreed on the need for a center-based child care health program, and wanted a better management of health care by health professionals in child care centers. Conclusion: These results support that there is a great demand for center-based child care health programs. These special programs are needed for reducing a child rearing burden for working mothers and overcoming the low birthrate in Korea. Health-care programs in child-care settings can help parents meet the health needs of their children while reducing absenteeism from work, thereby contributing to job stability. These results suggest discussions of the related policy with child care centers responsible and national health and educational authorities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.530-540
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• 2019

Objectives: The purpose of this study was to identify factors related with demographic and work characteristics that affect musculoskeletal pain and quality of life among personal assistants for people with severe disabilities. Methods: The subjects were recruited among personal assistant for people with severe disabilities who participated in refresher training held in K-si, Gyeonggi-do Province through convenience sampling. Using a survey instrument developed by the authors, subjects responded to questionnaires concerning muscluloskeletal pain and quality of life. The collected data was analyzed using SPSS 21.0. Basically, collected data was analyzed in terms of frequency, t-test or ANOVA and multiple regression analysis. Results: Total years of work experience and subjective physical workload were associated with the number of pain sites and intensity. Additionally, for quality of life, subjective physical workload was related in the regression model. Conclusions: Based on this study, we identified that characteristics of work affected the musculoskeletal pain and quality of life of personal assistants for the severely disabled, and suggested improvement of the working environment, including musculoskeletal pain prevention education programs during the refresher education for assistants to the severely disabled.

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.208-214
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• 2010

Green tobacco sickness (GTS) is an illness associated with nicotine exposures among tobacco harvesters. The purposes of this study were to measure the concentration of nicotine residues on the hands and forearms of tobacco harvesters, and to compare the concentrations according to the harvesting task. Wipe samples from the both hands and forearms were obtained from 16 workers at three sampling times (before work, in the morning after harvesting leaves, and in the afternoon after binding leaves). The geometric means of the right and left hand nicotine levels in harvesting work were 0.70 and $0.61\;{\mu}g/cm^2$, respectively, which were substantial, if significantly lower than the corresponding levels in binding work of 5.19 and $1.50\;{\mu}g/cm^2$ (p=0.016). The overall combined nicotine levels for the hands (i.e., left and right) were significantly higher than those for the forearms (p=0.013). The results of this study therefore indicate that, for GTS prevention, waterproof gloves should be worn while harvesting.

• Corrosion Science and Technology
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• v.2 no.6
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• pp.266-271
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• 2003

Safety diagnosis of various structural components and facilities is indispensable for preventing catastrophic failure of material by time-dependent and environment accelerating degradation. Also, this diagnosis of operating components should be done periodically for safe maintenance and economical repair. However, conventional standard methods for mechanical properties have the problems of bulky specimen, destructive procedure and complex procedure of specimen sampling. So, a non-destructive and simple mechanical testing method using small specimen is needed. Therefore, an advanced indentation technique was developed as a potential method for non-destructive testing of in-field structures. This technique measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation such as yield strength, tensile strength and work-hardening index. In this paper, we characterized the tensile properties including yield and tensile strengths of the V-modified Cr-Mo steels in petro-chemical and thermo-electrical plants. And also, the effects of hydrogen-assisted degradation of the V-modified Cr-Mo steels were analyzed in terms of work-hardening index and yield ratio.

• The Journal of Korean Academic Society of Nursing Education
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• v.13 no.1
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• pp.82-89
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• 2007

Purpose: The purpose of this study was to develop and evaluate an e-Learning Program designed to enhance novice nurses's performance ability Method: The e-Learning program was designed for novice nurses before beginning to work in a hospital using a KMS(Knowledge Management System). This study was carried out from February 2006 to April 2007. The program had progressive steps including design, pilot test & modification, contents development, program application and evaluation. After the program design and pilot testing, the learner's satisfaction was analyzed. Result: The program site is http://kms.emc.ac.kr titled, 'Cyber Education Center'. The sixteen part course has been developed as follows: blood sugar test, skin test, insulin test 1, insulin test 2, blood culture, blood sampling, heat therapy, cold therapy, glycerin enema, preparation of operation, oxygen therapy, suction technique, transfusion, foley catheterization and aseptic technique. The overall learner's satisfaction score was 4.08 out of 5 points. Conclusion: E-Learning could be useful for education and nursing work. This method may be effective for clinical nurses.