• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.81-84
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• 2000

This paper presents operating process and design method on the linear compressor Stirling cryocooler for cooling infrared detector. The free piston-type Stirling cryocooler, which applies 1) the Stirling cycle for refrigeration, 2) linear motors for driving, 3) flexure bearings for support systems, and 4) fine gap for clearance seals, is the most suitable design for a mechanical cryocooler utilized in a night vision environment.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.317-318
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• 2003

구미지역의 산업단지는 반도체, LCD, 브라운관, 정보통신기기 등 첨단전자 정보통신산업을 위주로 형성되어 있으며, 섬유와 기타 합성수지 산업도 위치하고 있다. 이러한 산업적 구조로 인하여 2002년도 현재 톨루엔은 년간 1029.4톤 이상을 사용하고 있으며, 배출량이 년간 200톤 이상으로 나타나 있다. 그리고 자일렌은 년간 1274.646톤의 사용량을 기록하고 있으며, 40톤 이상을 배출하고 있다(대구지방환경청, 2003). (중략)

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.01a
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• pp.407-408
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• 2023

In this paper, we intend to develop a multimodal algorithm that secures recognition performance of over 95% in daytime illumination environments and secures recognition performance of over 90% in bad weather (rainfall and snow) and night illumination environments.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.75-82
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• 1999

This study was carried out to examine the effect of day/nignt temperatures during seedling culture on the vegetative and reproductive growth of Lycopersicum esculentum ‘Seokwang’. The study was consisted of two culture stages, plug seedling production in the growth chamber and hydroponic culture of the plant in a glasshouse. Experiments were replicated over time. The germinated seedlings were raised for 33 days (experiment 1) and 35 days (experiment 2) in 4 growth chambers, each with day/night temperatures of either $25^{\circ}C$/$25^{\circ}C$, 16$^{\circ}C$/16$^{\circ}C$, 16$^{\circ}C$/$25^{\circ}C$ or $25^{\circ}C$/16$^{\circ}C$. Cool-white fluorescent lamps provided 140$\mu$mol.m$^{-2}$ .s$^{-1}$ light for 12h each day. In the second experiment, all chambers were supplied with 1000$\mu$mol.mol$^{-1}$ CO$_{2}$ during the photoperiod and had an air velocity of 0.3m.s$^{-1}$ and relative humidity of 80%. Plug seedlings raised were transplanted to rockwool slabs in a glasshouse and were grown hydroponically using the same nutrient solutions used for seedling culture for 37 days (experiment 1) and 35 days (experiment 2). Plant height was affected more by mean daily temperature than by interaction of day and night temperatures. Plant height was the highest in 16/16$^{\circ}C$ treatment. Leaf count was not affected by day and night temperatures, and the chlorophyll concentration was the highest in 16/$25^{\circ}C$ treatment. Fresh and dry weights of stem tended to be greater in treatments of constant day and night temperature. The number of node on which first and second flower clusters were set was significantly higher in 25/$25^{\circ}C$ treatment than in the other treatments. Days to flower of the first flower on the first flower cluster were the greatest in 25/$25^{\circ}C$ and the least in 16/$25^{\circ}C$ treatment. Vegetative and reproductive growth, such as height, fresh and dry weights, days to flower, and nodes of the 1st and 2nd flower cluster set were affected by day/night temperatures.

• Journal of People, Plants, and Environment
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• v.23 no.6
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• pp.655-665
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• 2020

Background and objective: This study was conducted to compare the cultivation environment, growth of cut flowers, and management performance of conventional farms and smart farms growing the standard cut chrysanthemum, 'Jinba'. Methods: Conventional and smart farms were selected, and facility information, cultivation environment, cut flower growth, and management performance were investigated. Results: The conventional and smart farms were located in Muan, Jeollanam-do, and conventional farming involved cultivating with soil culture in a plastic greenhouse, while the smart farm was cultivating with hydroponics in a plastic greenhouse. The conventional farm did not have sensors for environmental measurement such as light intensity and temperature and pH and EC sensors for fertigation, and all systems, including roof window, side window, thermal screen, and shading curtain, were operated manually. On the other hand, the smart farm was equipped with sensors for measuring the environment and nutrient solution, and was automatically controlled. The day and night mean temperatures, relative humidity, and solar radiation in the facilities of the conventional and the smart farm were managed similarly. But in the floral differentiation stage, the floral differentiation was delayed, as the night temperature of conventional farm was managed as low as 17.7℃ which was lower than smart farm. Accordingly, the harvest of cut flowers by the conventional farm was delayed to 35 days later than that of the smart farm. Also, soil moisture and EC of the conventional farm were unnecessarily kept higher than those of the smart farm in the early growth stage, and then were maintained relatively low during the period after floral differentiation, when a lot of water and nutrients were required. Therefore, growth of cut flower, cut flower length, number of leaves, flower diameter, and weight were poorer in the conventional farm than in the smart farm. In terms of management performance, yield and sales price were 10% and 38% higher for the smart farm than for the conventional farm, respectively. Also, the net income was 2,298 thousand won more for the smart farm than for the conventional farm. Conclusion: It was suggested that the improved growth of cut flowers and high management performance of the smart farm were due to precise environment management for growth by the automatic control and sensor.

• Journal of Korean Academy of Nursing Administration
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• v.18 no.4
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• pp.414-423
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• 2012

Purpose: The purpose of this study was to investigate the impact of the unit-level nurse practice environment on nurse turnover intention in the small and medium sized hospitals. Methods: A cross-sectional study was conducted using a questionnaire survey with 308 nurses in 38 nursing units of 6 small and medium sized hospitals, having over 200 beds and under 300 beds and located in B metropolitan city. Data were collected from July 20 to August 10, 2011. Data were analyzed using hierarchical multiple regression. Results: The mean turnover intention in nurses of small and medium sized hospitals was $3.52{\pm}0.53$. Factors affecting turnover intention in the nurses included age, work unit, monthly income, number of night-duties, work hours per day and unit-level nurse practice environment. The unit-level nurse practice environment accounted for 15% of turnover intention when other variables were controlled. Conclusion: The results of the study indicate that nurse turnover intention is associated with the nurse practice environment at the unit level. Small and medium sized hospitals can improve nurse retention and lower turnover intention by changing the nurse practice environment of unit, such as creating better support services and nurse participation in hospital affairs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.3
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• pp.1-9
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• 2009

This study investigated the actual condition focusing on the lighting environment which is a major element in aspect of indoor environment of a public library and assessed user satisfaction. Research results are as follows: Firstly, numbers of lighting fixtures per dimension of a reading room in a public library were inconsistent due to the lack of definite regulations, which was found to have negative effect on night time illuminance. Secondly, it was assessed that illuminance between the day time influenced by natural lighting and in the nighttime without natural lighting has more than 10-fold difference. Therefore, such a condition is judged to be inappropriate for lighting environment of a reading room where users spend a long time studying and thus, it is considered that an appropriate measures should be taken. Thirdly, as the survey result on users' satisfaction with lighting environment was revealed to be lesser than 3 points, lighting plan in consideration of its users should be progressed.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.364-368
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• 2013

Vibrational energy harvester based on piezoelectricity has been expected to be the dominant energy harvesting technology due to the advantages of high conversion efficiency, light weight and small size, night operation, etc. Its commercialization is just around the corner but the integration with power management electronics should be solved in advance. In this paper, therefore, fully-integrated design environment for piezoelectric energy harvesting systems is presented to assist co-design with the power management electronics. The proposed design environment is capable of analyzing the energy harvester including the package-induced damping effects and simulating the device and its power management electronics simultaneously. When the developed design environment was applied to the fabricated device, the simulated resonant frequency matched well with the experimental result with a difference of 2.97% only. Also, the complex transient response was completed in short simulation time of 3,001 seconds including the displacement distribution over the device geometry. Furthermore, a full-bridge power management circuit was modeled and simulated with the energy harvester simultaneously. Therefore the proposed, fully-integrated design environment is accurate and fast enough for the contribution on successful commercialization of piezoelectric energy harvester.

• Journal of muscle and joint health
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• v.25 no.3
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• pp.196-204
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• 2018

Purpose: The purpose of this study was to contribute to the activation of comprehensive nursing care services by comparing and analyzing the working environment and operational status of comprehensive nursing care wards with general wards. Methods: A questionnaire survey was conducted at hospitals operating comprehensive nursing care services. We collected data on patient characteristics, workforce, working environment, and work support facilities of 40 hospitals voluntarily participating in the survey. The collected data were analyzed by dividing it into an comprehensive nursing care ward and a general ward. Results: Compared with the general ward, the comprehensive nursing care ward had fewer hospitalized patients, but the severity of the patients and the need for nursing were high. The number of nurses, assistant nurses, and ward support workers per patient was higher in the comprehensive nursing care ward than in the general ward, and the implementation rate of night shift fixed system, the fixed shift system, and the preceptor system were higher. In terms of structural environment, comprehensive nursing care wards had more room for interviews. Conclusion: The comprehensive nursing care ward had more nursing staff and provided a better working environment than the general ward, but required additional support for the structural environment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.3
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• pp.418-427
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• 2015

Objectives: This study evaluated the association between work related characteristics and hypertension among white collar workers in Korea. Materials and methods: This study was based on the Third Korean Working Conditions Survey(KWCS) conducted in 2011 among workers 15 years of age or older. The total number of individuals included in the analysis was 10,365 white collar workers. Results: The prevalence rate of hypertension was 3.7% among men and 1.0% among women. In multiple logistic analysis the adjusted odds ratio showed statistically effective association to hypertension. For work related characteristics, 1.73 (95% confidence interval, 1.22-2.46) resulted for large-company workers compared with the small-company group, 2.14 (95% CI, 1.22-3.75) for the long working hours group (61 or above) compared with short working hours group(52 or below), 1.78(95% CI, 1.08-2.95) for night shift workers compared with day workers, and 1.54 (95% CI, 1.18-2.01) for high job stress workers compared with low job stress workers. Conclusions: This study showed that it is important for workers to manage their work environment in order to prevent hypertension by modifying their types of work.