• 환경영향평가
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• 제13권5호
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• pp.243-250
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• 2004

Recently, concerns about health risks exposed to electromagnetic fields have been brought in the safety of electric power lines. A number of governmental and international organizations have advised to avoid the magnetic field exposure to the schools and residential areas. Some epidemiologic studies showed that electromagnetic fields should not exceed the exposure limits of 2-3mG to the people living near high-voltage transmission lines. In this study, the principles, ranges and survey methods of the assessment for powerfrequency electromagnetic fields were reviewed from the relevant research papers and documents. The ranges of electromagnetic fields were determined from 50m to 100m and have been defined according to the properties of each electric power lines and a new methodology was suggested in this study. It would be necessary to develop and improve specific assessment methods for various high-voltage transmission lines projects.

• 한국해양공학회지
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• 제37권4호
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• pp.137-144
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• 2023

This study investigates the experimental parameters of particle image velocimetry (PIV) to enhance the measurement technique for turbulent flow fields around a circular cylinder at a Reynolds number (Re) of 1.4×10⁵. At the Korea Research Institute of Ships & Ocean Engineering (KRISO), we utilized the cavitation tunnel and PIV system to capture the instantaneous flow fields and statistically obtained the mean flow fields. An aspect ratio and blockage ratio of 16.7% and 6.0%, respectively, were considered to minimize the tunnel wall effect on the cylinder wakes. The optimal values of the pulse time and the number of flow fields were determined by comparing the contours of mean streamlines, velocities, Reynolds shear stresses, and turbulent kinetic energy under their different values to ensure accurate and converged results. Based on the findings, we recommend a pulse time of 45 ㎲ corresponding to a particle moving time of 3-4 pixels, and at least 3,000 instantaneous flow fields to accurately obtain the mean flow fields. The results of the present study agree well with those of previous studies that examined the end of the subcritical flow regime.

• 한국환경복원기술학회지
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• 제9권2호
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• pp.1-15
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• 2006

As the imports of foreign agricultural products are liberalized and the consumption of agricultural products declines, abandoned rice paddy fields continues to rise. However, such abandoned rice paddy fields has not been precisely surveyed yet. In this backdrop, a necessity to develop technology to utilize such abandoned rice paddy fields has emerged. Utilization of abandoned rice paddy fields as wetlands may be a good example. This study aimed to survey the current status and characteristics of wetlands created within abandoned rice paddy fields by selecting abandoned rice paddy fields throughout the nation and conducting field surveys on the sites that had transformed into wetlands. The abandoned rice paddy fields almost transformed into wetland and the types of wetlands transformed from abandoned rice paddy fields were mainly Inland/Moutain/Depression/Abandoned rice paddy fields/Marsh/Phragmites communis community and Inland/Moutain/Depression/Abandoned rice paddy fields/Swamp/Salix koreensis community. Abandoned rice paddy fields that had transformed into wetlands was depending heavily on waterways for water supply than other reservoirs and lakes do. Abandoned rice paddy fields transformed into wetlands was most observed in mountainous area. Abandoned rice paddy fields are because agricultural land is no longer profitable due to international and social changes and is not cultivated as government policy. Wetland period and dimension originated from abandoned rice paddy fields are very various and its surrounding land its mostly forest and the next largest follow roads and rural community. The abandoned rice paddy fields transformed into wetlands is mostly deserted currently. Despite their value as wetlands, no restoration and utilization efforts are made in Korea today. Therefore, it is imperative to conduct a precise current status survey on these areas and introduce management and restoration plans at the government level in the case of important habitats.

• 한국주거학회논문집
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• 제8권2호
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• pp.123-134
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• 1997

The purposes of this study are to investigate the present conditions of children' Practical use of playing fields and playing facilities within their residential area, and to provide essential data relavant to building outdoor playing field for children which are fitted with children’ developmental features and also are corresponding to their needs. The subjects for this study were 866 children of the 2nd. 4th, and 6th grade living in Taegu. Data were gathered through questionnaires and analyzed by frequencies, percentile, and Chi-Sqaure test. The main results of this study are as follows : Firstly, it was found that the Playing fields children preferred most was 'within their house'. In terms of frequency making use of outdoor Playing fields. 'do not use' held the hightest proportion of children. Second, the playing facility in playing fields, being most frequently used by children, was a slide, following it a swing and a horizontal iron bar took the second, the third place respectively.

• 한국IT서비스학회지
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• 제6권3호
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• pp.141-162
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• 2007

In this study, we conduct a case analysis on EZmedicom which is one of the leading companies in e-Marketplace for medical fields. By examining major business models of EZmedicom, we provide the success factors in launching the electronic commerce to the potential companies which are interested in participating in e-marketplace for medical fields. Especially, we deduct the solution, logistics field, and electronic group-purchasing as its major business model. Based on these factors, we also propose the MDvan solution which is one of the electronic purchase and supply system, Ezlogis that is the system supporting logistics parts in medical fields, VMI(vendor management inventory), standardization of item code and the linkage of SCM as its critical success factors of EZmedicom. The findings of this study suggest practical and managerial implications for e-Marketplace implementation in the medical field and further research.

• 한국문헌정보학회지
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• 제33권3호
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• pp.63-86
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• 1999

본고는 소장데이터용 MARC 포맷의 일반적 특성과 개발현황에 대해 살펴보고, 아울러 MARC 포맷의 3요소로 일컬어지는 구조와, 내용표지법, 레코드의 내용을 이미 개발된 USMARC과 KORMARC 포맷을 중심으로 분석하였다. 레코드의 구조와 내용표지법은 서지용 및 전거용포맷과 대부분 동일하다. 데이터필드는 기본적으로 기능별블록으로 구분되어 있으나, 현재는 0XX, 5XX, 8XX 필드만이 사용되고 있다. 008 필드의 레코드 내용에는 수서와 보유정책 등 자료의 소장에 관련된 요소들이 추가되어 있다. 가변길이필드의 내용은 번호와 코드, 주기, 소재와 접근, 소장데이터 필드 등으로 구성되며, 특히 소장데이터필드는 다시 캡션과 패턴, 권호와 연대, 문장형식소장정보 자료정보 등의 필드로 구성된다. 본고에서는 각 필드별로 그 내용을 구체적으로 분석하고 있다.

• The Journal of Korean Physical Therapy
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• 제12권2호
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• pp.69-82
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• 2000

Physical therapists are exposured to radio-and microwave-frequency electromagnetic radiation by operating electrotherapy units. So there is few protection system in physical therapy room. Clinical pathology room and so on where various kins of electromagnetic instruments is used in hospital while protection failities like protection wall or protection glass is being used only in radiological room to reduce the damage of radiation. Acoording to Larsen's survey on female physical therapist in denmark. it was said that the percentage of congenital malfornation was $3.6\%$ and cadiac malformation made up $0.7\%$. It is likely that effect of electromagnetic fields on the result cannot be ruled out. Rita ouellet-Hellstron and Walter F. Steward insisted that the danger of abortion increase in the case of pregnant femeal physical therapist exposured to microwave diathermy. The intention of our study is arousing the necessity of microwave protection in P.T room and finding the proper method for physical therapist safe. The results of this study were as follows: 1. Each electrotherapy units are occurrenced the electromagnetic fields, and specially amply occurrenced in H.P,I.C.T 2 unit operating, M.W.D unit head on parallel, S.W.D unit head on parallel. all electrotherapy units are operating. 2. There were electric fields mount are consideration to species of electrotherapy units(p<.05). 3. There were magnetic fields mount are consideration to species of electrotherapy units(p<.05). 4. There were electric fields mount are consideration to distance of electrotherapy units(p<.05). 7. There were magnetic fields mount are consideration nut to distance of electrotherapy units(p>.05). 8. Before and after protection on magnetic fields mount are consideration to all distance(0m, 0.3m, 1m, 3m, 5m)(p<.05) 9. Before and after protection on electric fields mount are consideration to 0m, 1m, 3m distance(p<.05), and consideration not to 0.3m, 5m distance(p>.05) 10. After protection fellow the each electrotherapy units. distance, intencity to electromagnetic fields are reduced(p<.05).

• 기술혁신학회지
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• 제2권1호
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• pp.16-27
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• 1999

This paper intends to clear up the conte31t of the interdisciplinary nature of individual researches. First, the interdisciplinary character of individual research was analyzed. Approximately 40% of individual research projects supported by Korea Science and Engineering Foundation has the interdisciplinary nature. Second, there are close connections among research fields in individual research projects. Every research field needs the inflow of knowledge from other fields and supports other research fields as well. The interrelation among various research fields indicates the importance of the balanced development in all science and engineering fields.

• 한국안전학회지
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• 제36권4호
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• pp.20-28
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• 2021

With an increase in the commercialization of electricity, and the development of advanced and large electric devices and various wireless radio wave services, concerns over the effects of electromagnetic fields on human health have increased. Accordingly, the World Health Organization encouraged the development of international standards by establishing the 'International Electromagnetic Fields Project' in 1996 based on studies on the harmful effects of electromagnetic fields on the human body. Moreover, the National Institute of Environmental Health Sciences (NIEHS) classified electromagnetic fields as possible carcinogens under Group 2B category, even though they have been found to have a weak correlation with those effects on human health. Mid-to-large-sized electric facilities used at industrial sites mostly adopt a commercial frequency of 60 Hz, and workers handling these facilities are exposed to such extremely low frequency (ELF) fields for a long time. A previous study suggested that exposure to ELF electromagnetic fields with frequency ranges from 0 to 300 Hz, even for a short time, at densities higher than 100 μT may have harmful effects on human body as it affects the activation of nerve cells in the central nervous system by inducing an electric field and current and stimulating muscles and the nervous system in the body. Such studies, however, focused on home appliances used by ordinary people, and research on facilities utilizing high-capacity current and operated by workers at industrial sites is lacking. Therefore, in this study, a 3000 kilowatt generator, which is a high-capacity electric facility employed at industrial sites, was investigated, and the size of the magnetic fields generated during its no-load and high-load operations per distance to produce a map was measured to reveal spots deemed hazardous according to domestic and international exposure standards. The findings of this study is expected to alleviate workers' anxiety about the harmful effects of magnetic fields on their body and to minimize the level of exposure during operations.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.346-346
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• 2017

In Northern Laos, maize is cultivated in continuous cropping without fertilizer, fallowing nor any other soil conservation practice. It is expected that this inadequate management in maize cultivation will degrade soil and decrease yield. However, there is limited information about the change of soil condition and yield under continuous maize cultivation. We tried to evaluate the change of soil condition and yield under continuous maize cultivation in Northern Laos. Our study was conducted in farmer's flat and slope fields in Sainyabuli province where maize cultivation had been introduced earlier than the other provinces of Northern Laos. Our study was conducted in 21 fields in 2014, and in 19 fields in 2015. We analyzed grain yield and soil characteristic (total carbon (TC), total nitrogen (TN), available phosphorus (Av-P), exchangeable cation, pH, soil texture) at 3 places in each field. The 3 places were set at different elevation level (lower position, middle position, upper position) in slope fields. Further, the period of continuous maize cultivation and crop management practice were investigated. Then, by evaluating the relation between the period of continuous maize cultivation and yield and the soil characteristics, the effect of maize cultivation was estimated. Crop management practices were similar among the investigated fields. Maize was cultivated in rain season. Grain seed and cob were harvested on September or October, but shoot was left on the fields. No crop was cultivated during dry season. Fertilization and fallowing has never been conducted under continuous maize cultivation. On the other hand, the period of maize cultivation was different among the fields, and ranged from 2 years to 30 years. In the slope fields, as the period of continuous maize cultivation was longer, the contents of TC and TN were lower at all 3 positions, Av-P content was lower at the upper position, exchangeable potassium (Ex-K) content was lower at the middle and the upper positions. The other soil characteristics weren't related with the period of maize cultivation in the slope fields. In contrast, soil characteristics weren't related with the period of maize cultivation in the flat fields. Yield was lower as the period of maize cultivation was longer at the upper position of the slope fields. At middle position of slope fields, yield tended to be low with increase of the period of maize cultivation. In contrast, yield wasn't related with the period of continuous maize cultivation in flat fields. From the results about crop management, it was presumed that the period of maize cultivation was one of the main factors causing the difference of yield and soil characteristics among the fields. Therefore, from the result of yield and soil condition, it was considered that the continuous maize cultivation decreased soil productivity in the slope fields with decline of TC, TN, Av-P, Ex-K and yield at upper position of slope fields, and decline of TC and TN in the other positions in Sainyabuli province.