• Geophysics and Geophysical Exploration
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• 제18권3호
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• pp.115-124
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• 2015

A modified electrical resistivity survey has been suggested and applied to a leakage detection problem of concrete barrage. We suggest the modified electrical resistivity methods using electrodes floating on the water and apply line current sources instead of conventional point current sources in order to facilitate simple analysis. In addition, the study introduced the following three variations of modified electrode array: Direct potential array, Parallel potential array and Cross potential array. These arrays were tested and investigated through numerical experiment, physical model experiment and geophysical field exploration in order to verify their applicability to the water leakage detection of a concrete barrage. When water leakage occurred, all kind of array operations demonstrated distinct changes of aspects of potential difference in graphs obtained by not only the numerical and physical model experiments but also geophysical field exploration. Therefore, this modified electrode arrays of electrical resistivity survey, which has been adapted to the concrete barrage, has been found to be a useful method to detect water leakage.

• Korean Journal of Remote Sensing
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• 제8권2호
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• pp.93-104
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• 1992

Although the Transverse Mercator(TM) coordinate is used on standard topogrphic maps of Korea as a supplement to regular latitude-longitude coordinate, the use of this TM coordinate system is rather limited to a single coordinate zone that spans only two degrees of longitude. With growing applications of a variety of digiral geographic data, such as satellite remote sensor data, a Cartesian or rectangular coordinate system is more effective to deal with such data type than angular coordinate system. An unified rectangular coordinate system based on the Transverse Mercator projection is designed to cover the whole area of the Korea Peninsula as a single coordinate zone. Considering the width of the peninsula and the distribution of scale error, the origin of the coordinate is determined to 127$^{\circ}$30' east and 38$^{\circ}$ north. Coordinate conversion procedure is discussed along with the corresponding scale error term.

• Journal of Korean Society of Transportation
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• 제27권1호
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• pp.191-200
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• 2009

This study develops composite indicators that is capable of estimating QOS (Quality of Service) of pedestrians by enhancing estimation for Level of Service in present transporting spaces for pedestrians that merely concerns quantitative indicators such as pedestrian flow rate, pedestrian stoppage. This paper conducts survey questionnaire to collect data. It utilizes AHP(Analytic Hierarchy Process) and ANP(Analytic Network Process). The main results show that: first, ANP is better analytic methods than AHP due to the fact that pedestrians feel repetition when they judge level of service. Second, qualitative factors such as pedestrian behaviors, maintenance, scenary for pedestrians and environments should be considered. Importance of qualitative factors is higher in residential area than other areas. I expect that using qualitative indicators and quantitative indicators is appropriate in order to estimate pedestrians' QOS.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.444-448
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• 2007

자연하천에서 단위구간(측선)의 연직선상 평균유속산정을 위한 일반적인 측정방법으로는 표면유속법, 1점법, 2점법, 3점법, 4점법, 5점법, 6점법, 연직 유속분포법 등이 있으며, 본 연구에서는 지난 1년간 낙동강유역 이안, 신풍, 성덕(무계), 성덕(보현)지점에서 회전식유속계로 측정한 유속자료를 이용하여 측선별 연직분포곡선을 작성한 후 측정지점 횡단면상 수심이 얕은 양안과 상류 제약조건(수풀 또는 돌출된 바위 등)으로 인해 측선의 흐름이 왜곡되는 지점을 제외한 측선별 연직유속분포곡선을 평균하여 지점별 대표 연직유속분포곡선을 작성하였다. 지점별 대표 연직유속분포 곡선을 작성하여 평균유속을 산정한 값을 기준으로 하천유량 측정시 일반적 평균유속 산정방법인 1, 2, 3점법 및 표면유속법에 대한 변동계수를 분석한 결과 1점법은 0.064, 2점법은 0.027, 3점법은 0.043, 표면유속법은 0.126으로 1, 2, 3 점법에서는 지점별 변화가 비교적 작게 나타났으며 표면유속법에서는 유량측정 지점별 변화가 큰 것으로 나타났다. 또한, 낙동지점에서 ADCP를 이용한 유량측정시 수집된 측선별 연직유속분포자료를 이용, 측정지점의 유량별 대표 연직유속분포 곡선을 작성, 실제 하천유량측정에 널리 쓰이고 있는 평균유속 측정방법을 비교 분석하였다. 분석결과, 1점법에서는 평균유속대비 1.076, 2점법에서는 1.026, 3점법에서는 0.051로서 2, 3점법이 대체로 양호한 결과를 보이며 이는 Hulsing 등의 연직유속분포곡선을 이용하여 계산한 1점법에서 1.020, 2점법, 1.010, 3점법 1.015의 결과 추세와도 일치하였다.

• Journal of the Korean Applied Science and Technology
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• 제37권2호
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• pp.340-353
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• 2020

The purpose of this study is to introduce surfing which is not a familiar leisure activity in Korea and provide understanding of surfing participants through the cross-sectional analysis on the process of forming recreational specialization from introductory levels with enthusiastic surfing participants. This study employs a qualitative approach to analyze each participant's experience on recreation specialization in detail, and in particular uses ethnographic research methods to derive participants' meaning of life and daily routines and cultural behavioral patterns changed through surfing. First, through the analysis of in-depth interview data, total 531 conceptual words were identified and the first categorization was established. Second, surfing participants mentioned that they had high expectations of surfing even before they first encountered it. Third, surfing participants noted that they experienced leisure constraints and made efforts to resolve this issue before reaching the recreation specialization process. Fourth, surfing participants were found to go through a recreation specialization process. Fifth, surfing participants were found to undergo life changes. They worked hard in their everyday life through physical training, improvement of surfing skills, and analysis of their own videos to be better at surfing.

• Journal of the Korean Wood Science and Technology
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• 제46권1호
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• pp.29-37
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• 2018

Bamboo is one of the major biomass resources in the world. To obtain valuable information for effective use of bamboo resources in Korea, the anatomical characteristics of the commercial Korean bamboo species (Phyllostachys pubescens, Phyllostachys nigra, and Phyllostachys bambusoides) were analyzed. The structures in bamboo culm were observed by optical and scanning electron microscopy. Also the crystalline properties as relative crystallinity and crystallite width were measured by an X-ray diffraction method. The three Korean bamboo species had the vascular bundle type I with tylosoid in intercellular space. In the outer part of culm, vascular bundles showed denser spacing than inner part. The fiber length in outer part samples of the three bamboo species showed longer than inner part samples. Furthermore, the fiber length showed a significant difference between inner part and outer part in three bamboo species, showing the longest fiber length in Phyllostachys bambusoides. Phyllostachys pubescens showed the greatest diameter in vessel and parenchyma on cross section. Parenchyma cells in Phyllostachys pubescens and Phyllostachys bambusoides showed similar length and width in both radial and tangential sections. The relative crystallinity and crystallite width in outer part samples of the three bamboo species showed higher values than those in inner part samples, with the greatest values from Phyllostachys bambusoides.

• The Journal of the Korea Contents Association
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• 제21권8호
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• pp.247-257
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• 2021

It seems likely that the characteristics of future society will include an emphasis on diverse and expansive data sets and the use of AI technology. Because of this, school leaders within the traditional, textbook based educational framework there will be changes should meet the 2015 Revised National Curriculum and prepare students for future societies. The purpose of this research paper was to suggest the nature of and policies necessary for better educational processes in middle and high schools after they've been improved in accordance with the 2015 Revised National Curriculum. This paper implemented its survey and interview of school principals through the guidelines provided by UNESCO Bangkok's transversal competence research. Analysis results and research participants were practicing strengthened education in the course of their daily activities. The educators involved received positive evaluation from their students. Further, pedagogical opinions were suggested regarding the effects of school principals on various strengthened education elements. This paper's suggestions within the context of the 2015 Revised National Curriculum are expected to continue reinforcing the overall positive effect of the currently in practice strengthened education methods. Furthermore, it can contribute to the development of the next National Curriculum with empricial data.

• Journal of the Society of Naval Architects of Korea
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• 제43권3호
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• pp.322-330
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• 2006

Numerical calculations are carried out for flow past a circular cylinder forced oscillating normal to the free-stream flow at a fixed Reynolds number equal to 185. The cylinder oscillation frequency ranged from 0.8 to 1.2 of the natural vortex-shedding frequency, and the oscillation amplitude extended up to 20% of the cylinder diameter. IBM (Immersed Boundary Method) with direct momentum forcing was adopted to handle both of a stationary and an oscillating cylinder Present results such as time histories of drag and lift coefficients for both stationary and oscillating cases are in good agreement with previous numerical and experimental results. The instantaneous wake patterns of oscillating cylinder with different oscillating frequency ratios showed the synchronized wakes pattern in the lock-in region and vortex switching phenomenon at higher frequency ratio than the critical frequency ratio.

• Journal of the Korean Institute of Gas
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• 제13권3호
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• pp.7-14
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• 2009

Many countries are managing the transportation of hazardous materials under the specific provisions especially, as well as use, storage and management, because of their high risks. For the purpose of the revision of rail safety law for the safe transportation of hazardous materials, amount and kind of hazardous materials transported by rail in Korea are analysed and the standards of classification of hazardous materials are compared in domestic and abroad. There are lots of benefits for national rail safety law to implement an international law because our country's geographic location is convenient to connect the continent and to across the border. It is suggested that implementing a classification and test methods of hazardous materials enable to use internationally for the preparation of rail transportation to be increased.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2010년도 학술발표회
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• pp.488-493
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• 2010

하천 유량자료는 조사 목적에 따라 시간, 일, 월 등 다양한 시간범위를 갖는다. 이러한 특성을 갖는 유량 자료를 확보하기 위해 정해진 시간에 유량측정을 시행하는 것은 경제적, 기술적으로 매우 어려운 일이다. 따라서 연속적인 유량생산은 상대적으로 연속측정이 용이한 수위자료를 연속측정하고, 간헐적인 유량측정을 통하여 수위-유량관계를 수립하여, 수립된 관계를 연속적으로 측정된 수위자료에 대입하여 이루어진다. 그러나 준설에 의한 하상변동, 가물막이 등 하천횡단 구조물 설치에 따른 통제특성 변화, 공사 등에 의한 하천경사 변화 등에 의해 수위-유량관계의 연속적인 변화가 발생할 경우 하나의 수위-유량관계로 연속적인 유량환산이 불가능하게 된다. 따라서 자연현상 및 각종 공사에 의해 하도 특성이 변화할 경우 신뢰도 높은 유량을 신속하게 제공할 수 있는 새로운 기법 적용이 요구된다. 본 연구에서는 4대강 사업구간에 위치한 유량관측소에서 전통적인 수위-유량관계 곡선법, 기간분리에 의한 방법, Stout 방법, 비유량법 등 다양한 방법을 활용하여 연속 유량자료를 생산 기법을 제시하고자 한다.