• 한국산업융합학회 논문집
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• 제23권2_2호
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• pp.199-207
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• 2020

These days, many different types of valves are developed in the industrial area according to their use purpose. Multiple kinds of valves are installed to control a flow and pressure of the pipe conveying fluid. Valves serve as critical roles in land plants such as power plants. The performance of equipment varies depending on valve characteristics. In this study, the internal flow analysis on Cone-type valve is conducted to analyze flow field and secure a value of the flow coefficient Cv. According to the internal flow analysis, when the flow distribution of the middle cross-section of valve was open 100%, flow field was relatively and smoothly taken out. If it was open 50%, flow recirculation region increased and a little complex flow field occurred. Unlike ball valve or butterfly valve, this valve had flow recirculation in its outlet depending on a valve opening amount. Therefore, it was found that there was no flow recirculation in the outlet of Cone-type valve.

• 한국의학물리학회지:의학물리
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• 제4권1호
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• pp.55-71
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• 1993

Measured and calculated the TMR and SMR factors from percent depth dose underpartial attenuators which cover the whole part of the radiation beam with variousfilter thickness from 0 to 50 mm. This study was performed for x-ray beams generated with a 6 MV linear acceleratorat source to surface distance of 100cm in a water phantom for Lipowitz metal. TMR(0,d,t) was derived from non-linear polynomial regression with field sizedifferencies and a given filter thickness. In this experiments, the TMR(0,10,50) of 50mm of filter thickness was showed13.6 % higher than that of open field and SMR(5,10,50) was 38.5% smaller than thatof open field in same depth.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.463-467
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• 2008

The fact that the major cases of life casualties are from smoke in the fire accidents and the expected steep increase of skyscrapers, huge spaces, multiplexes and huge scaled underground spaces demand establishment of efficient smoke countermeasure. The field experiments on pressure differential systems for smoke management in two high buildings of 20 stories and 21 stories are carried out to evaluate the features of airflow through open door between accommodation and lobby. The procedures and results of experiments are presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.701-708
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• 2003

This paper presents an acoustic source localization technique on 2D cavity model in flow using a phased microphone way. Investigation was performed on cavity flows of open and closed types. The source distributions on 2D cavity flow were investigated in anechoic open-jet wind tunnel. The array of microphones was placed outside the flow to measure the far field acoustic signals. The optimum sensor placement was decided by varying the relative location of the microphones to improve the spatial resolution. Pressure transducers were flush-mounted on the cavity surface to measure the near-filed pressures. It is shown that the propagated far field acoustic pressures are closely correlated to the near-field pressures. It is also shown that their spectral contents are affected by the cavity parameter L/D.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1766-1769
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• 2008

INnterior noise characteristic of Korean tilting train(Hanvit 200) under the field test conditions is analyzed in this paper. The test railroad track was selected from Seodaejon to Songjeongri in Honam line. $4^{th}$ and $5^{th}$ car are decided to measure interior noise level among a train of six cars. The test subject open field executed from test sections. The speed of test trains when from existing operation speed and speed up 20% of existing speed. On open field at the time of operation speed of Hanvit 200 trains from below 160km/h interior noise level at $68dBA{\sim}70dBA$.

• 한국환경농학회지
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• 제39권3호
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• pp.237-245
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• 2020

BACKGROUND: The closed chamber method is the most commonly used for measuring greenhouse gas emissions from upland fields. This method has the advantages of being simple, easily available and economical. However, uncertainty estimation is essential for accurate assessment of greenhouse gas emissions and verification of emission reductions. The nitrous oxide emissions from upland field is very important for the nitrogen budget in the agriculture sectors. Although assessment of uncertainty components affecting nitrous oxide emission from upland field is necessary to take account of dispersion characteristics, research on these uncertainty components is very rare to date. This study aims at elucidation of influencing factors on measurement uncertainty of nitrous oxide concentrations measured by an automated open closed chamber method from upland field. METHODS AND RESULTS: The nitrous oxide sampling system is located in the upland field in Gyeonggi-do Agricultural Research and Extension Services (37°13'22"N, 127°02'22"E). The primary measurement uncertainty components influencing nitrous oxide concentrations (influencing factors) investigated in this research are repeatability, reproducibility and calibration in the aspects of nitrous oxide sampling and analytical instrumentation. The magnitudes of the relative standard uncertainty of each influencing factor are quantified and compared. CONCLUSION: Results of this study show what influencing factors are more important in determination of nitrous oxide concentrations measured using the automated open closed chambers located in the monitoring site. Quantifying the measurement uncertainty of the nitrous oxide concentrations in this study would contribute to improving measurement quality of nitrous oxide fluxes.

• 영재교육연구
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• 제19권1호
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• pp.1-23
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• 2009

과학 탐방 학습은 학생이 스스로 문제를 해결할 수 있는 종합적 학습 활동으로 영재 학습에서의 중요성이 강조되고 있다. 그러나 너무 많은 양의 과제를 해결하거나, 정해진 답을 요구하는 수렴적 활동이 주로 이루어져 영재학생의 능력을 개발하는데 부족하다는 비판을 받고 있다. 따라서 이 연구에서는 과학영재의 지적 특성을 반영하기 위하여 개방적 탐구를 토대로 하는 탐방 프로그램을 고안하였다. 이를 초등 과학 영재학생 18명을 대상으로 적용하였고, 탐방 활동지, 상호작용 녹음내용, 발표용 포스터, 설문지 등의 자료를 바탕으로 탐구문제 설정 유형 및 탐구 과정, 탐방 활동 중에 나타나는 과학 영재의 활동 과정을 분석하였다. 연구결과 탐방 전보다 탐방 후에 더 많은 탐구문제를 만들 뿐만 아니라 탐구문제의 수준도 더 높아졌다. 이를 해결하는 탐구과정은 계획하기, 탐구 수행하기, 후속 탐구하기, 정리하기의 순서에 의해 순환적으로 이루어졌으며, 상황에 따라 다음 단계를 결정하는 개방적 탐구 과정으로 진행되었다. 학생들의 문제해결 과정에서 기초 탐구과정 및 통합 탐구과정 요소가 다양하게 나타났으며, 특히 결과를 해석하고 변환하여 분석하는 능력이 뛰어났다. 또한 탐방 활동 중에 나타난 학생들의 상호 작용을 분석한 결과 과학 영재의 행동적 특성이 다양하게 나타났다.

• 무역상무연구
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• 제69권
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• pp.633-654
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• 2016

Recently open data has been spread rapidly in the world include Korea. Accordingly in international trade field open data and using it became a key point to get competitiveness. In this study, the author make an attempt to suggest the way for quality improvement of international trade information by looking for some problems with crating and using the information. Thus, the problems of using information are can be point out as follows. Firstly the range of open data is narrow. Secondly the management of the open data is not conducted properly. Thirdly the suppliers of the open data didn't prepare some investigation system for their data's usability for user. Expansion of the organizations who open data is one way to solve quantitative problem. There are four suggestions to solve qualitative problems. Firstly the guidelines should be established and operated in each organizations respectively. Secondly the criterion of expenses for open data should be arranged among the concerned parties. Thirdly the ability of the manpower and organization who charged in the quality improvement of information should be reinforced both quantitatively and qualitatively. Lastly the system for data usability for user should be equipped in early stages. Finally the author emphasize the establishment of total management system for using open data in international trade is not needed only the efforts of the specific parties but also all parties led by Ministry of Industry, Trade and Energy in order to carry out above suggestions successfully.

• 한국정보통신학회논문지
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• 제13권2호
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• pp.437-444
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• 2009

유엔을 비롯한 국제단체와 각국의 정부에서는 공개 소프트웨어 보급을 위해 많은 노력을 기울이고 있다. 우리나라에서도 공개 소프트웨어를 활성화하기 위한 노력의 일환으로 공개소프트웨어 시범 사업을 시행하고 정보화 사업 평가 항목에 공개 소프트웨어 사용하면 가점을 부여하고 있다. 그러나 잠재적인 공개 소프트웨어 사용자들인 중등학교 학생을 대상으로 공개 소프트웨어에 대한 홍보와 교육이 부족한 상태이다. 본 연구에서는 현재 중등학교에서 학생들의 공개 소프트웨어에 대한 인지도를 파악하고 분석한다. 그리고 공개소프트웨어를 중등학교의 개정된 7차 교육과정 의 정보 교과에서 활용할 수 있는 방안을 제시한다.

• 한국정보통신학회논문지
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• 제11권12호
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• pp.2419-2425
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• 2007

정부에서는 공개소프트웨어 보급을 위해 많은 노력을 기울이고 있다. 이의 일환으로 공개소프트웨어 시범 사업을 시행하고 있으며 정보화 사업 평가 항목에 공개소프트웨어 사용 여부 포함하고 있다. 그러나 잠재적인 공개소프트웨어 사용자인 중등학교 학생들을 대상으로 공개소프트웨어에 대한 홍보와 교육이 부족한 상태이다. 본 연구에서는 현재 중등학교에서 정보 교과를 담당하는 교사들의 공개소프트웨어에 대한 인지도를 파악하고 분석한다. 이 연구 결과는 중등학교에서의 공개소프트웨어 교육을 활성화하기 위해 방안을 찾는데 기초 자료로 활용 될 수 있다.