• Steel and Composite Structures
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• v.51 no.5
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• pp.487-498
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• 2024

Steel moment resisting frames (MRFs) typically have inter-story drift concentrations at lower stories during earthquakes as found from previous research. Hinged walls (HWs) can be used as structural strengthening components to force the MRFs deform uniformly along the building height. However, large moment demands are often observed on HWs and make the design of HWs non-economical. This paper proposes a method to reduce the moment demand on HWs using a ductile connection system between the MRFs and the HWs. The ductile connection system is designed with a yield strength and energy dissipation capacity, for the purpose of limiting the seismic forces transferred to the HWs and dissipating seismic energy. Nonlinear time history analyses were performed using 10 far-filed earthquakes at maximum considered earthquake level. The analysis results show that the proposed ductile connection system can reduce: (1) seismic moment demands in the HWs; (2) floor accelerations; (3) the connection force between HWs and MRFs.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.4
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• pp.13-21
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• 2021

The feasibility of HWS for agricultural use was analyzed through a crop cultivation test to utilize the hydroponic waste solution (HWS) generated from the nutriculture greenhouse. The fertilizing effect of HWS was assessed on the basis of the inorganic nitrogen (N) mostly existed in HWSs, and nitrogen (urea) fertilizer. Lettuce was selected as the target crop influenced by the soil treatment and also for the crop cultivation test. Thus, the change in growth characteristics of lettuce and that in chemical characteristics of the soil were investigated. In terms of the growth of lettuce, the C control group with 70% nitrogen (urea) fertilizer and 30% HWS and the D control group with 50% nitrogen (urea) fertilizer and 50% HWS were more effective than the practice control group (B) with 100% nitrogen (urea) fertilizer. The results of this study confirmed the combined applicability of the chemical fertilizer and HWS for crop cultivation. Because NO₃-N present in HWS has a high possibility of leaching into the soil, its applicability as a fertilizer has been considered to be relatively low in Korea. However, if an appropriate mixing ratio of urea fertilizer and HWS could be applied, the problems associated with leaching of nitrate nitrogen could be reduced with beneficial effects on crop cultivation. Thus, future studies are required on the treatment effect of HWS with repeated cultivation, impact assessment on the surrounding environment, and appropriate fertilization methods using nitrogen (urea) fertilizer and HWS. These studies would facilitate the sustainable recycling of HWS.

• Safety and Health at Work
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• v.11 no.3
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• pp.262-265
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• 2020

Coronavirus disease 2019 (Covid-19) poses an important occupational health risk to health workers (HWs) that has attracted global scrutiny. To date, several thousand HWs globally have been reported as infected with the severe acute respiratory syndrome coronavirus 2 virus that causes the disease. It is therefore a public health priority for policymakers to understand risk factors for this vulnerable group to avert occupational transmission. A rapid review was carried out on 20 April 2020 on Covid-19 risk factors among HWs in PubMed, Google Scholar, and EBSCOHost Web (Academic Search Complete, CINAHL Complete, MEDLINE with Full Text, CINAHL with Full Text, APA PsycInfo, Health Source-Consumer Edition, Health Source: Nursing/Academic Edition) and WHO Global Database. We also searched for preprints on the medRxiv database. We searched for reports, reviews, and primary observational studies (case control, case cross-over, cross-sectional, and cohort). The review included studies conducted among HWs with Covid-19 that reported risk factors irrespective of their sample size. Eleven studies met the inclusion criteria. Lack of personal protective equipment, exposure to infected patients, work overload, poor infection control, and preexisting medical conditions were identified as risk factors for Covid-19 among HWs. In the context of Covid-19, HWs face an unprecedented occupational risk of morbidity and mortality. There is need for rapid development of sustainable measures that protect HWs from the pandemic.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.353-363
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• 2020

Objectives: Occupational diseases that occur due to or aggravated by work have commonly been recognized in the manufacturing industry, but there are now more incidences happening in the service industry due to changes in the industrial structure. Health workers are exposed to direct factors and various other causes of occupational disease at work, such as physical, chemical, biological, and psyco-social factors. This study aims to identify work-related diseases affecting health workers that are recognized as occupational diseases. Methods: The research is based on the data of workers whose diseases were accepted as work-related by the Industrial Accidents Compensation Insurance, and filed by the Korean Occupational Safety and Health Agency. Amongst the approved claims during 2011 to 2015, we focused on healthcare workers and health-related workers of the Korean Standard Classification of Occupations. Descriptive statistics were performed. Results: The number of health workers(HWs) with approved work-related disease was 1,707 over 5 years. The number of healthcare workers(HCWs) excluding caregivers was 370 (21.7%) and of health-related workers (HRWs) it was 736 (43.1%). Out of HWs who were approved for their illnesses, females were 80% of HCWs and 88% of HRWs. The most common occupational disease in HWs was musculoskeletal diseases, while that of nurses was infectious disease. Conclusions: HWs are exposed to various risks from their profession and are affected by occupational diseases. It is necessary to focus on this issue and provide preventive measures.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.7.1-7.14
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• 2023

Background: At present, no short standard questionnaire exists for assessing and comparing major work organization hazards in the workplaces of the United States. Methods: We conducted a series of psychometric tests (content validity, factor analysis, differential-item functioning analysis, reliability, and concurrent validity) to validate and identify core items and scales for major work organization hazards using the data from the 2002-2014 General Social Surveys (GSSs), including the Quality of Worklife (QWL) questionnaire. In addition, an extensive literature review was undertaken to find other major work organization hazards which were not addressed in the GSS. Results: Although the overall validity of the GSS-QWL questionnaire was satisfactory in the psychometric tests, some GSS-QWL items of work-family conflict, psychological job demands, job insecurity, use of skills on the job, and safety climate scales appeared to be weak. In the end, 33 questions (31 GSS-QWL and 2 GSS) were chosen as the least, but best validated core questions and included in a new short standard questionnaire (called the Healthy Work Survey [HWS]). And their national norms were established for comparisons. Furthermore, based on the literature review, fifteen more questions for assessing other significant work organization hazards (e.g., lack of scheduling control, emotional demands, electronic surveillance, wage theft) were included in the new questionnaire. Thus, the HWS includes 48 questions in total for assessing traditional and emerging work organization hazards, which covers seven theoretical domains: work schedule/arrangement, control, support, reward, demands, safety, and justice. Conclusions: The HWS is a short standard questionnaire for assessing work organization hazards which can be used as a first step toward the risk management of major work organization hazards in the workplaces of the US.

• Journal of the Korean Society of Tobacco Science
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• v.26 no.2 s.52
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• pp.126-134
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• 2004

Tobacco dust samples were collected for two times in primary and secondary process at 4 cigarette manufacturing factories(Shintanzin, Youngju, Wonju, Kwangju) and analyzed to evaluate usage as a raw material in production of reconstituted tobacco. The chemical constituents and HWS of tobacco dust were analyzed. Tobacco dust samples were partitioned by particle size using a series of screens ranging from 20 to 200 mesh. The amount of material retained in each fraction was quantified and sand content was also determined. Appreciable average amounts$(40-65\%)$ material at 4 locations were found to be larger than 60 mesh. Although the amount of material in each fraction increased to a maximum at 100 mesh and then decreased, the $\%$ sand continually increased with decreasing particle size. The chemical constituents and HWS content of tobacco dust have similar values in secondary process of 4 cigarette manufacturing factories but the those of primary process have different values according to the site of occurrence and manufacturing factories.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.4
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• pp.201-208
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• 2003

The Hybrid Wall System(HWS) building composed of center core reinforced concrete walls and exterior steel frame has open space around the center core walls. It is necessary to develop design methodologies for the HWS building that the coupled shear walls withstand the most of lateral load and expect the most energy dissipation at the coupling beams and at wall foots. Major factors considered in this paper are connection type of coupling beams and scale of story. The studies of the system are investigated in terms of shear force, overturning moment, maximum lateral displacement, story drift ratio, and dynamical characteristics under the action of vertical and lateral forces such as wind and seismic loads.

• Safety and Health at Work
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• v.12 no.3
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• pp.304-310
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• 2021

Background: Healthcare settings have been recognized among the most hazardous places to work. Based on the five categories of occupational hazards that were identified by the ILO and WHO, this study aimed to analyze policy framework relevant to occupational health protection of health workers (HWs) in public health service in China, then discussed how to share the experience of the National Health Service (NHS) England for improvement. Methods: Based on policy learning theories, policy analysis and qualitative interview were used in this study. Results: In the Chinese public health service, at least five laws related to the regulation of occupational health protection for HWs; however, enforcement of relevant laws was separated and multi-centered; the national monitoring system, which targeted to occupational hazards and health outcome for HWs in China, had yet to be developed; the top three priorities were workplace violence, bloodborne pathogens, and musculoskeletal disorders; national strategies included Security Hospital, and Healthy China 2030. In NHS England, three laws were fundamental; several monitoring systems had been set up, including NHS Staff Survey, Commissioning for Quality and Innovation incentive scheme; mental health, musculoskeletal problem, and nutrition disorder and overweight were raised great concern; Health and Safety, and NHS Healthy Workforce Program were critical nationwide strategies. Conclusion: There were several similarities as well as differences between the Chinese public health system and NHS England, which laid foundation of learning by China. Recommendations of improving occupational health policies in China were provided, based on the lessons learned from the NHS England.

• Atmosphere
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• v.32 no.4
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• pp.277-295
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• 2022

The global weather prediction model, Korean Integrated Model (KIM), has been in operation since April 2020 by the Korea Meteorological Administration. This study assessed the performance of heat waves (HWs) in Korea in 2020. Case experiments during 2018-2020 were conducted to support the reliability of assessment, and the factors which affect predictability of the HWs were analyzed. Simulated expansion and retreat of the Tibetan High and North Pacific High during the 2020 HW had a good agreement with the analysis. However, the model showed significant cold biases in the maximum surface temperature. It was found that the temperature bias was highly related to underestimation of downward shortwave radiation at surface, which was linked to cloudiness. KIM tended to overestimate nighttime clouds that delayed the dissipation of cloud in the morning, which affected the shortage of downward solar radiation. The vertical profiles of temperature and moisture showed that cold bias and trapped moisture in the lower atmosphere produce favorable conditions for cloud formation over the Yellow Sea, which affected overestimation of cloud in downwind land. Sensitivity test was performed to reduce model bias, which was done by modulating moisture mixing parameter in the boundary layer scheme. Results indicated that the daytime temperature errors were reduced by increase in surface solar irradiance with enhanced cloud dissipation. This study suggested that not only the synoptic features but also the accuracy of low-level temperature and moisture condition played an important role in predicting the maximum temperature during the HWs in medium-range forecasts.

• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.217-224
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• 2008

To obtain optimum configuration, depth and load of constructed wetlands(CWs) for treating of hydroponic waste solution(HWS) which was produced in greenhouses, the study was conducted with 4 kinds of combined systems such as Vertical flow(VF)-Horizontal flow(HF), VF-VF, HF-VF and HF-HF CWs. In four configurations of CWs, the treatment efficiency of pollutants from HWS under depth of HF and VF beds, HWS loading and HWSs were investigated. Removal rate of pollutants under different depth of VF and HF in 2-stage hybrid CWs was in the order of 50 cm < 70 cm regardless of CWs configuration. Removal rate of pollutants under HWS loading in 2-stage hybrid CWs was in the order of $150L\;m^{-2}\;day^{-1}{\fallingdotseq}300L\;m^{-2}\;day^{-1}\;>\;450L\;m^{-2}\;day^{-1}$. The optimum depth and HWS loading were 70 cm and $300L\;m^{-2}\;day^{-1}$ in four configurations of CWs, respectively. Using this optimum condition, for various HWSs (cucumber, paprika and strawberry HWS), removal rate of pollutants in HF-HF CWs was higher than that in HF-VF CWs. Optimum configuration of 2-stage hybrid CWs for treating hydroponic waste solution in greenhouses was found out to be HF-HF CWs. Therefore, under the optimum conditions, removal rate of BOD, COD, SS, T-N and T-P in HF-HF CWs were 84, 81, 84, 51 and 93%, respectively.