• Journal of the Korean Society of Safety
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• v.38 no.4
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• pp.32-38
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• 2023

Job stress factors are factors that induce biological, psychological, and behavioral responses in individuals when they encounter mental and physical stimuli in the workplace. According to occupational safety and health standards, employers are responsible for the health consequences of job stress when workers engage in activities that result in high levels of physical fatigue and mental stress. Such activities include long working hours, shift work (including night shifts), driving vehicles, and operating precision machinery. Therefore, precautionary measures should be implemented. Following the COVID-19 epidemic, the logistics industry in Korea has experienced rapid growth owing to the shift from offline to online platforms facilitated by advanced digital infrastructure. Consequently, this study conducted a survey to analyze job stress factors among delivery workers. The survey utilized a Korean job stress factor assessment tool comprising 43 items and analyzed job stress factors considering the work characteristics of the courier business field obtained from responses provided by 421 courier workers nationwide. The survey analysis revealed that the physical environment, job demands, and job autonomy exhibited higher stress indices among Korean workers. Furthermore, the younger the age, the higher the stress on job demands, whereas the higher the age, the higher the stress on relationship conflict, job instability, and workplace culture. In addition, daytime delivery work was associated with higher stress levels in job demands and job instability compared with nighttime delivery work. These findings can serve as foundational data for reducing and preventing job stress among courier workers, whose workload has increased owing to the growth of the logistics industry.

• Safety and Health at Work
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• v.7 no.2
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• pp.111-119
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• 2016

Background: Shift work and/or sleep quality may affect health. We investigated whether shift work and sleep quality, separately and jointly, were associated with abnormal levels of triglycerides, total cholesterol (TC), and low-and high-density lipoprotein cholesterol in 360 police officers (27.5% women). Methods: Triglycerides, TC, and high-density lipoprotein were analyzed on the Abbott Architect; low-density lipoprotein was calculated. Shift work was assessed using City of Buffalo payroll work history records. Sleep quality (good, ${\leq}5$; intermediate, 6-8; poor, ${\geq}9$) was assessed using the Pittsburgh Sleep Quality Index questionnaire. A shift work + sleep quality variable was created: day plus good sleep; day plus poor sleep; afternoon/night plus good; and poor sleep quality. Mean values of lipid biomarkers were compared across categories of the exposures using analysis of variance/analysis of covariance. Results: Shift work was not significantly associated with lipids. However, as sleep quality worsened, mean levels of triglycerides and TC gradually increased but only among female officers (age- and race-adjusted p = 0.013 and 0.030, respectively). Age significantly modified the association between sleep quality and TC. Among officers ${\geq}40$ years old, those reporting poor sleep quality had a significantly higher mean level of TC ($202.9{\pm}3.7mg/dL$) compared with those reporting good sleep quality ($190.6{\pm}4.0mg/dL$) (gender- and race-adjusted p = 0.010). Female officers who worked the day shift and also reported good sleep quality had the lowest mean level of TC compared with women in the other three categories (p = 0.014). Conclusion: Sleep quality and its combined influence with shift work may play a role in the alteration of some lipid measures.

• Atmosphere
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• v.23 no.3
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• pp.307-320
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• 2013

We performed comprehensive quality control for eddy-covariance measurements from 3 farmland sites and 1 industrial site adjacent to Nakdong river. The quality control program is based on Foken and Wichura (1996) and Vicker and Mahrt (1997) and we added criteria for trend and standard deviation for scalar variables and modified criteria for non-stationarity condition of Foken and Wichura (1996) to consider random error of fluxes. The classification of data quality is designed for the raw data and the processed flux data, separately. Use of added criteria efficiently reduces the number of outlier for water vapor and $CO_2$ fluxes and use of modified criteria for non-stationarity reduces the number of outlier for scalar fluxes and increases the number of data with accepted quality for further work. Energy balance ratio is higher in farmlands than industrial site, which is due to neglect of heat storage term in industrial site. Among farmland sites, C4 site shows higher energy balance ratio than other sites. This is due to more homogeneous surface of C4 site than other farmland sites. However, energy balance ratio is very low or even negative at night. Mismatch between the flux footprint and the other energy component footprint over the heterogeneous surface is main cause for energy imbalance at night. Other possible causes are also discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.579-589
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• 1985

The storage tank of the natural-circulation-solar-hot-water system equipped with flat-plate solar collectors is located at higher elevation than the solar collectors. Therefore, the heat loss from the system due to a reversed flow during the night-time is an important factor as well as the day-time thermal performance of the system. The thermal performance of the natural-circulation-solar-hot-water system with flat-plate solar collectors during the day-time depends mainly on the heat collecting efficiency of the solar collectors, whereas its thermal performance during the night-time depends on the system configuration , such as the elevation of the water storage tank with respect to the solar collectors and the piping connections between the storage tank and the solar collectors, as well as thermo-physical properties of the circulating fluid. In the present work, a computer program has been developed to simulate a typical natural-circulation-solar-hot-water-system, and a series of simulation tests have been carried out with the computer program to examine the thermal performance of the system during the day-time as well as the hight-time. In addition , a series of experiment have been conducted under a real sun condition using a natural-circulation-solar-hot-water-system constructed and installed at the KAIST building to compare with the results obtained from computer simulations.

• Journal of dental hygiene science
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• v.20 no.1
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• pp.59-66
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• 2020

Background: This study aims to analyze the job stress of dental hygienists and the factors affecting somatization and to provide basic data for effectively managing job stress and somatization of dental hygienists. Methods: In this study, the data collected from 208 dental hygienists working in Jeollabuk-do Province were analyzed. Job stress was investigated using a questionnaire with 43 questions. In addition, the degree of somatization was evaluated through a simplified psychotherapy examination (Symptom Check List-90-Revision). Results: Age, employment history, position, average monthly income, night duty execution status, and perceived health status were significantly associated with job stress (p<0.05). The job stress sub-items scores based on general characteristics showed significance in 'workload' for those working a five-day workweek and perceived health status (p<0.05). Age, average monthly income, and perceived health status were noted in 'role conflict as a professional'. In 'lack of expertise and skill', it was noted that age, employment history, position, income, and night clinic were implemented. In 'improper treatment and interpersonal issues', level of education and perceived health status were significant (p<0.05). The higher the job stress, the higher the somatization symptom score (p<0.05), and the higher the job stress component, the higher the somatization symptom score (p<0.01). Conclusion: The job stress of dental hygienists should be reduced, and the symptoms of somatization should be mitigated. To improve the quality of medical services and the work efficiency of dental hygienists, proper treatment and compensation systems should be implemented for them to take pride as professional. Further, programs and regulations on mitigating job stress and somatization symptoms should be developed.

• Korean Journal of Clinical Pharmacy
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• v.12 no.2
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• pp.85-90
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• 2002

The aim of this study was to examine the current turnover status of hospital pharmacists and to analyze the factors which affected the turnover of them after the separation of prescribing and dispensing practice. We surveyed 19 managers of hospital pharmacies and 154 hospital pharmacists. Results are as follows. Pharmacist manpower of hospital pharmacies was only $63.99\%$ in tertiary hospitals and $76.78\%$ in general hospitals respectively of the number of pharmacists before the separation of prescription and dispensing practice. The ratio of those who left hospital pharmacies during the period of January 2000 and October 2001 was $80.23\%$ for tertiary hospitals, and $100.84\%$ for general hospitals. Decrease in the number of pharmacists brought the increase of work load and night duty. Major factors which affected the turnover of hospital pharmacists were found as following: income gap between hospital pharmacists and community pharmacists, increasing workload especially at night and on holidays, infrequent chance for the promotion, and low chance to provide clinical pharmacy services after the separation of prescribing and dispensing practice. Adequate manpower is the basic factor for providing hospital pharmacy services and improving clinical pharmacy services. The study suggested that proper number of hospital pharmacists is to be ensured through strengthening the legal requirement for the hospital pharmacists and improving health insurance reimbursement rate for the pharmaceutical services at hospital.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.89-94
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• 2019

K1A1 tank commander's primary thermal sight is a device that enables tank commanders to detect, identify, aim and track the target by observing targets in all directions during day, night and in situations of smokescreen and fog through $360^{\circ}$ rotation independent from the gunner's primary thermal sight and stabilizing the line of sight even under the vibrations occurring when the tank is standstill and moving. The main function of this device is to detect and process visible and thermal images and deliver the final images to the tank commander. One of the core parts to that end is the observation window (daytime/thermal image window). This core part is mounted at the entrance of the optical path for observing the target and plays the role of making visible light during the daytime and infrared light during the night pass through the target and transmitting the resultant images to the internal optical system of the tank commander's primary thermal sight. Such core parts have been selected as depot maintenance items so that they are replaced by new parts instead of being recycled when they are subjected to maintenance in most cases. That is, the military budget is wasted because such parts are replaced by new parts despite that they can be recycled for maintenance. Therefore, this study proposed a mounting tool for polishing and coating observation windows (daytime and thermal image window) using planar polishing equipment and DLC (Diamond-Like Carbon) coating equipment. In addition, this study presented an amendment (proposal) of the Depot Maintenance Work Request (DMWR) already published to verify the performance of recycled products including the establishment of inspection standards for recycling processes.

• International Journal of Contents
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• v.16 no.4
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• pp.68-77
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• 2020

VR (Virtual Reality) contents make the audience perceive virtual space as real through the virtual Z axis which creates a space that could not be created in 2D due to the space between the eyes of the audience. This visual change has led to the need for technological changes to sound and sound sources inserted into VR contents. However, studies to increase immersion in VR contents are still more focused on scientific and visual fields. This is because composing and producing VR sounds require professional views in two areas: sound-based engineering and computer-based interactive sound engineering. Sound-based engineering is difficult to reflect changes in user interaction or time and space by directing the sound effects, script sound, and background music according to the storyboard organized by the director. However, it has the advantage of producing the sound effects, script sound, and background music in one track and not having to go through the coding phase. Computer-based interactive sound engineering, on the other hand, is produced in different files, including the sound effects, script sound, and background music. It can increase immersion by reflecting user interaction or time and space, but it can also suffer from noise cancelling and sound collisions. Therefore in this study, the following methods were devised and utilized to produce sound for VR contents called "A Midsummer Night" so as to take advantage of each sound-making technology. First, the storyboard is analyzed according to the user's interaction. It is to analyze sound effects, script sound, and background music which is required according to user interaction. Second, the sounds are classified and analyzed as 'simultaneous sound' and 'individual sound'. Thirdly, work on interaction coding for sound effects, script sound, and background music that were produced from the simultaneous sound and individual time sound categories is done. Then, the contents are completed by applying the sound to the video. By going through the process, sound quality inhibitors such as noise cancelling can be removed while allowing sound production that fits to user interaction and time and space.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.117-120
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• 2007

The main purpose of this paper is to introduce the early traffic opening-capable continuous multi-layer asphalt pavement maintenance method using electric arc furnace slag aggregate and emulsified asphalt to the actual construction sites. As well known, the previous surface treatment method of emulsified asphalt mixture have various shortcomings such as long work-time, traffic congestions, plastic deformation and poor evenness. Thus, the proposed method has enabled tile early traffic opening by utilizing the optimized emulsified asphalt after consideration of the climate and road conditions in Korea. The application of the electric furnace slag with $6\;{\sim}\;18\;mm$ thickness is helpful to become a environment-friendly construction method. And also, it has been improved enough to accommodate night-time works of mechanized construction activities for wearing course and control course.

• Korean Journal of Pharmacognosy
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• v.34 no.4 s.135
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• pp.318-323
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• 2003

Extracts of Black cohosh (Cimicifugae rhizoma) have been used for the treatment of climacteric complaints for decades. A significant number of woman entering menopause exhibit the following symptoms: getting hot flushes, night sweats, irritability, depression, and anxiety, A reduction of the frequency of hot flushes equivalents and hints on the antidepressant activity of Cimcifuga extracts. In the present work, we have screened several 80% ethanol extracts from medicinal plants and found that the extracts from Cimicifugae Rhizoma(Black cohosh:승마) have inhibitory effect on catecholamine secretion in bovine chromaffin cell. Since this extract inhibited 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP)-induced catecholamine secretion, but did not inhibit KCl, bradykinin, and veratridine-evoked case, this inhibitory effect is mediated by nicotinic acetylcholine receptors with noncompetitive manner.