• The Journal of Engineering Geology
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• v.14 no.1
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• pp.29-46
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• 2004

It is important to identify geometries of fracture that act as a conduit of fluid flow for characterization of ground water flow in fractured rock. Fracture geometries control hydraulic conductivity and stream lines in a rock mass. However, we have difficulties to acquire whole geometric data of fractures in a field scale because of discontinuous distribution of outcrops and impossibility of continuous collecting of subsurface data. Therefore, it is needed to develop a method to describe whole feature of a target fracture geometry. This study suggests a new approach to develop a method to characterize on the whole feature of a target fracture geometry based on the Fourier transform. After sampling of specimens along a target fracture from borehole cores, effective frequencies among roughness components were selected by the Fourier transform on each specimen. Then, the selected effective frequencies were averaged on each frequency. Because the averaged spectrum includes all the frequency profiles of each specimen, it shows the representative components of the fracture roughness of the target fracture. The inverse Fourier transform is conducted to reconstruct an averaged whole roughness feature after low pass filtering. The reconstructed roughness feature also shows the representative roughness of the target subsurface fracture including the geometrical characteristics of each specimen. It also means that overall roughness feature by scaling up of a fracture. In order to identify the characteristics of permeability coefficients along the target fracture, fracture models were constructed based on the reconstructed roughness feature. The computation of permeability coefficient was performed by the homogenization analysis that can calculate accurate permeability coefficients with full consideration of fracture geometry. The results show a range between $10^{-4}{\;}and{\;}10^{-3}{\;}cm/sec$, indicating reasonable values of permeability coefficient along a large fracture. This approach will be effectively applied to the analysis of permeability characteristics along a large fracture as well as identification of the whole feature of a fracture in a field scale.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.685-696
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• 2013

The purpose of the present study is to explore the career development barriers of female doctoral degree holders in education. The study occupied in-depth interview with 42 female doctoral degree holders in education. The results were as followed; First, academic advisor highly influenced the career development female doctoral degree holders through their academic activities. Second, they had experiences regarding glass ceiling effect in workplace. Third, marriage was a critical issue for both of the married and single female doctoral degree holders. Fourth, family and relatives' support positively impact on their career will, and also their strong career goal was beneficial way to break their career barriers. Also, the study suggested contextural factor was very significant on career behavior of female doctoral degree holders. Therefore, policy maker, scholars, and students should have strong attention to female students' career guidance and development in various way. The results of the study discussed in relation to the existing literature, with reference to women's career development and career barriers, and then implication for the future research were suggested.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.109-117
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• 2010

With the advent of new technologies such as HSDPA, WiBro(Wireless Broadband) and personal devices, we can access various contents and services anytime and anywhere. A location based service(LBS) is essential for providing personalized services with individual location information in ubiquitous computing environment. In this paper, we propose mapping algorithm for error compensation of indoor localization system. Also we explain filter and indoor localization system. we have developed mapping algorithms composed of a map recognition method and a position compensation method. The map recognition method achieves physical space recognition and map element relation extraction. We improved the accuracy of position searching. In addition, we reduced position errors using a dynamic scale factor.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.101-104
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• 2015

In this paper, a flight techniques many quadcopters which can be configured flexibly squadron according to the situation in wireless sensor networks is suggested. In previous studies, aircrafts fly only as part of a prescribed form and know the distance between the aircraft by sensor was able to maintain the fleet. Also, the problem occurs that between the aircraft distance is not constant. In this paper, proposes an algorithm that the context of the formation fly using the current position of the quadcopter through a virtual map is based on the relative coordinates without being affected by Indoor, outdoor and obstacles. Proposed algorithm is Leader-Follower Technique that the method of determinin the shape of the squadron to the down command to the sub-quadcopter using the wireless network by the main quadcopter to determine a given situation. As simulation result, the proposed algorithm was confirmed that formation flight efficient in sensing the all conditions as compared to the conventional method.

• Proceedings of the Korean Society for the Gifted Conference
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• 2003.05a
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• pp.143-144
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• 2003

6차 교육과정부터는 과학 교육에서 학생들의 학습 목표를 과학 개념에 대한 이해 뿐 아니라 탐구 사고력 및 기능 향상도 중요한 목표로서 취급하고 있다(교육부, 1992). 그런데 학생의 탐구 사고력을 향상시킬 수 있는 과학교육이 제대로 이루어지지 못하고 있는 것이 현재의 실정이다. Schwab(1961)가 탐구 학습의 단계를 분류하면서 지적한 바 있듯이 탐구는 주어진 과제를 해결하는 고정적 탐구보다는 스스로 과제를 설정하고 이를 해결하려 하는 유동적 탐구가 더 바람직한 방향이며, 이러한 유형의 탐구를 통하여 학생들은 창의성의 신장과 함께 과학적탐구가 이루어지는 과정을 더 올바르게 이해할 수 있을 것으로 생각된다. 따라서 탐구의 상황을 학교 실험실만이 아닌 좀 더 생활 주변의 여러 가지 경험과 관련된 쪽으로 안내하는 것도 필요하다. 최근 활발한 컴퓨터의 보급과 인터넷 환경의 확대로 인하여 학생들이 이러한 환경에서 교사와 직접 동일한 시간, 동일한 장소에서 대면하지 않고도 의사소통하고 교수-학습이 이루어질 수 있는 기회가 사회적으로 가능해지고 있다. 이러한 원격교육은 교사의 안내에 따른 탐구 교수 형태의 개념 확인 및 검증 실험이 대부분인 전통적 과학학습 방법과 달리 학생 스스로 문제를 찾고 해결하려고 시도하는 것을 통하여 과학적 탐구 기능의 향상은 물론 과학적 개념의 획득, 과학, 사회, 기술에 대한 폭넓은 인식을 형성하는데 도움이 된다. 또한 인터넷 환경을 이용하면 학교 실험실 상황을 벗어나 학생들에게 다양한 탐구 활동 기회를 제공할 수 있고, 또한 그에 따른 의사 소통이 더 용이해질 수 있다. 이에 따라서 본 연구에서는 탐구 과정기술과 사고력을 중시하는 초등학교 과학과목의 특성을 고려하여 이에 적합한 인터넷 원격교수-학습을 위한 교수-학습 모형과 학생들의 과학적 탐구력과 사고력을 신장시킬 수 있는 멀티미디어 학습자료를 개발하고, 이를 실제적으로 적용할 수 있는 웹사이트를 개발, 현장에 적용하여 원격교수학습이 과학적 탐구력과 사고력에 미치는 효과에 대하여 조사하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.1-7
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• 2013

An aerodynamic rig test of a radial turbine for an auxiliary power unit (APU) was performed at a high-temperature turbine test facility at the Korea Aerospace Research Institute. The pressure ratio, Mach number, and flow coefficient in the rig test are the same as those under normal engine operation conditions. The design pressure ratio is 3.096, design test speed is 34909 rpm, and turbine inlet temperature is $160^{\circ}C$. The turbine has airfoil-type nozzles, and the diameter of the turbine wheel is 175.74 mm. The turbine map is experimentally measured, and the detailed flow at the turbine inlet is measured. The pressure distribution in the nozzle at both the hub and the shroud sides and the pressure distribution along the shroud casing of the turbine wheel were measured, and this confirmed that the expansion process in the turbine wheel is acceptable.

• Journal of Nutrition and Health
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• v.3 no.2
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• pp.65-80
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• 1970

영유아 시기의 영양여하는 그 시기에 있어서 뿐만 아니라 일생을 통한 정신적 육체적 성장발육 및 질병에 대한 저항력, 이환율과 사망율, 그리고 국민 평균여명에 까지도 영향을 미치는 것으로서 그 중요성은 잘 알려져 있는 사실이다. 저자들은 우리나라에 있어서 이유기를 전후한 식품 섭취양상을 엿보기 위하여 전국을 도시, 읍, 평야, 산간 및 섬 지역으로 나누어 만 3세 미만의 어린이 304명을 대상으로 봄과 가을 2회에 걸쳐 조사를 실시하여 다음과 같은 결과를 얻었다. 1. 7개월까지는 모두가 모유를 먹고 있었으며 1예는 우유를 먹고 있었다. 8개월 이후 17개월까지는 약 10%에서, 18개월에서 23개월 사이에는 약 50%가 이유를 끝냈으며 30개월과 35개월 사이에는 84%가 이유를 완료하고 있었다. 2. 모유를 18개월 까지는 하루 4회이상, 그리고 그 후 30개월까지도 2회 이상씩 계속 먹이다가 그 후 갑자기 그치고 있었다. 3. 적절한 유동식이나 보조식등의 이유식이 없이 일반 성인음식을 그대로 먹이고 있었으며 동물성 단백질이나 지방질 섭취는 적었고 식물성 단백질음식도 묽은 국물 형태도 섭취하고 있었다. 4. 채소류와 멸치등은 쉽게 구할 수 있음에도 불구하고 충분히 보급받지 못하고 있었다. 5. 체중 및 신장의 신체계측에 의한 발육상태는 6개월 내지 12개월 경부터 뒤지기 시작하여 그후 계속발육지연을 보여주고 있었다. 6. 심한 단백 ${\ulcorner}$칼로리${\lrcorner}$ 영양실조증 환자가 1예 있었으며 다른 1예는 영양소모증 환자였다. 7. 상완위 측정결과는 3개월 이하의 남아를 제외하고는 모두가 충분한 크기에 달하지는 못했다. 8. 영양결핍양상을 신장에서는 지수 1이 5.9%, 체중에서는 지수 1이 8.9%, 2가 1.3%, 4가 1.0%로서 체중 전체로는 11.2%였고, 상박위에 있어서는 지수 2,3,4 가 도합 8.9%였다. 9. 1-3세의 유아 사망률은 12.3%였고 이유기 설사발병율이 19.7%였다. 이상의 결과로 우리나라 영육아들에 있어서 적절한 시기에 적절한 방법으로 이유를 실시하므로써 이 시기의 질병발생율 및 사망율의 저하를 가져올 수 있고 나아가서는 신체발육양상을 호전시킬 수 있을 것이다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.235-243
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• 2019

Radioactive materials are released into the air and deposited on the surface soil after a nuclear accident. Radionuclides deposited in soil are transported by precipitation to nearby environments and contaminate the surface water system. Basic data on surface watershed and soil erosion models have been collected and analyzed to evaluate the behavior of radionuclides deposited on surface soil after a nuclear accident. Data acquisition and analysis in aquatic environment were performed to investigate the physical characteristics and variation of biota in rivers and lakes of the Nakdong river area near the Wolsong nuclear power plant. For these purposes, a digital map, and hydrological, water quality and biota data were gathered and a systematic database (DB) was constructed in connection with them. Constructed aquatic DB will be supplied and used in surface watershed and soil erosion models for investigation of long-term movement of radionuclides in adsorptive form in surface soil. Finally, basic data and established models will be utilized for general radiological impact assessment in aquatic environment.

• Journal of The Korean Association For Science Education
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• v.41 no.1
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• pp.19-32
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• 2021

This study aims to analyze the visual modeling process of pre-service elementary teachers on the reflection of light. The analytical framework was developed from three aspects; coherence, correspondence, and commensurability of the modeling thinking proposed by Halloun (2004). 20 pre-service elementary teachers participated and were randomly paired to observe the reflection of light. They were asked to construct the visual model individually at first and then collaboratively. Comparing personal and cooperative models, the level of correspondence and commensurability in some groups has increased, despite the lack of special educational treatment. In addition, three main features were found in their reasoning process. First, the level of commensurability to apply the law of reflection continued to change fluidly depending on the circumstances and often the verbal and visual explanations did not match. Second, in the process of visual modeling, correspondence was often given priority over commensurability and coherence. Third, in a situation where correspondence and commensurability are at odds with each other, participants resolved this conflict and developed reasoning through review and revision of the auxiliary hypothesis. Several implications have been discussed for effectively guiding visual modeling activities.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.13-21
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• 2021

This study aims to analyze tourist inflow trends and consumption patterns using a geographic information system and big data analysis system. Songdo Central Park and Chinatown were selected among the major tourist destinations in Incheon, and floating population analysis and card sales analysis were conducted for one month in June 2017. The number of tourists visiting Songdo Central Park from metropolitan cities across the country was highest in the order of Incheon Metropolitan City, Gyeonggi-do, and Seoul Metropolitan City, and the proportion of foreign tourists was the highest in China. The number of card consumption used by Chinatown tourists was 12.4% higher for men than for women, and the amount of card consumption was also higher for men by 18%. This study has implications for proposing a strategic plan for tourism policy by analyzing the inflow trend and consumption pattern of tourists and deriving major issues in the establishment of tourism policy. Based on this study, it is expected that it can be helpful in improving the construction of tourism infrastructure in the future.