• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.5
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• pp.19-24
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• 1975

The problem of realizing a driving-Point impedance, the argument, $\theta$o, of which is as constant as possible over a given frequency reange was considered. An optimal design technique was applied by varying systematically the shape of the distributed element and the parameter values of the lumped elements. As a result it was possible to make the argument over two decades of frequencies within-2.5$^{\circ}$ for $\theta$o=- 30$^{\circ}$ and -60$^{\circ}$ and very flat above a certain frequency for $\theta$o=-45$^{\circ}$.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.175-184
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• 1997

In this study, the basic theory of geomagnetism was introduced and the field data of first order magnetic survey was analyzed to determine geographical distribution of magnetic elements such as Declination(D), Inclination(1), Horizontal Component(H), Vertical Component(Z) and Total Force(F). From this distribution equations, the distribution of geomagnetism of Korean peninsula was examined and the declination was calculated for National Base Maps.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.2
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• pp.47-56
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• 2000

지반-구조물 상호작용 시스템 구조물의 진동제어 시스템 복합재료 구조물과 같은 비비례 감쇠 구조물의 경우 정확한 동적응답을 얻기 위해서는 감쇠행렬을 고려한 고유치 문제를 계산하는 것이 필수적이다 그러나 대부분의 고유치 해법에서는 구하고자 하는 고유치 중 일부를 누락시킬 수 있기 때문에 어떤 고유치 해법이 실제문제에 응용 가능한 방법이 되기 위해서는 누락된 고유치의 존재 여부를 검사하는 기법을 포함하고 있어야만 한다. 비감쇠나 비례감쇠 시스템의 경우에는 널리 알려진 Sturm 수열성질을 이용하여 누락된 고유치를 쉽게 검사할 수 있는 반면에 비비례 감쇠 시스템의 경우에는 널리 알려진 Sturm 수열 성질을 이용하여 누락된 고유치를 쉽게 검사할 수 있는 반면에 비비례 감쇠 시스템의 경우에는 아직까지 검사 기법이 개발되어 있지않다 본 논문에서는 편각의 원리를 이용하여 감쇠행렬을 고려한 고유치 문제의 누락된 고유치의 존재여부를 검사하는 기법을 제안하였다 제안방법의 효용성을 검증하기 위하여 두가지 수치예제를 고려하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11a
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• pp.767-770
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• 2002

영상 검색의 수행 방법으로 사람의 시각 시스템의 특성을 기반으로 웨이블릿 변환의 고주파수 에너지와 형태학적 필터링을 이용하여 분할된 객체의 효과적인 특징 추출을 통한 계층적인 검색 시스템을 제안한다. 영상 고유의 특징을 얻기 위해 객체의 형태 정보와 질감(texture) 방향성 및 칼라 정보를 이용한다. 본 논문에서는 객체의 형태 정보의 추출을 위하여 사용자의 질의(query)영상에서 객체의 윤곽선의 편각차분 변동율에 의한 형태 특징 벡터를 추출하고 GLCM (Gray Level Co-occurrence Matrix)의 Contrast를 질감 특징으로 추출한다. 이들 두 특징을 이용하여 1차 분류 과정을 거치고 2차 검사에서는 보다 정확한 검색을 수행하기 위하여 1차로 분류된 후보영상들에 대하여 세부 정보인 칼라 정보를 기반으로 유사도를 측정함으로써 유사한 칼라와 형태를 가지는 영상뿐만 아니라 칼라가 다른 유사한 영상에도 효율적인 검색 성능을 보였다.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.235-241
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• 1988

This study was carried out to investigate some morphological characters of fruit bodies of Ganoderma lucidum and to classify the fungus on the bases of the genetic character. Some of the isolates of the fungus which originally have the kidney-shaped fruit bodies produced the antler-shaped fruit bodies on artificial media and the latter characters were inherited. Pattern of the pileus surface and thickness of the pileus of the fruit bodies were also considered to be hereditary. Although morphology of the pileus margin and fruiting mode of the fungus were variable among the isolates, they were greatly influenced by environment conditions. Ganoderma lucidum could be classified into two groups and four strains according to the morphology of the fruit bodies on artificial cultivation media. Electrophoretic patterns of esterase, peroxidase, leucine aminopeptidase(LAP) and proteins of fruit bodies and mycelia of Ganoderma lucidum showed high genetic variation. Isozyme patterns of esterase of the mushroom mycelia were applicable for the classification of strains of the fungus. Patterns of proteins, leucine aminopeptidase and peroxidase did not indicate any genetic relation among the fungus strains.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.350-354
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• 1994

A study was conducted on the characteristics of 11 strains of Ganoderma sp. to select the strains with more bitterness. Among the flat type strains, ASI 7071 and 7091 showed higher bitterness, while among the branched type strains ASI 7074 and 7094 were found to more bitter than other strains. The growth of ASI 7091 was best on Ganoderma complete media(GCM), while ASI 7010, 7048 and 7075 performed best in oak saw dust media. Among the branched type strains the esterase isozyme band patterns were similar. On the other hand among the flat type strains, the esterase isozyme band patterns differed from each other. Out of 11 strains, ASI 7004 was found to have the heaviest fruiting body, ASI 7071 the thickest cap and ASI 7094 the biggest cap.

• Journal of Korea Water Resources Association
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• v.53 no.1
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• pp.15-27
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• 2020

Streamflow discharge as a fundamental riverine quantity plays a crucial role in water resources management, thereby requiring accurate in-situ measurement. Recent advances in instrumentations for the streamflow discharge measurement has complemented or substituted classical devices and methods. Among various potential methods, surface current meter using microwave has increasingly begun to be applied not only for flood but also normal flow discharge measurement, remotely and safely enabling practitioners to measure flow velocity postulating indirect contact. With minimized field preparedness, this method facilitated and eased flood discharge measurement in the difficult in-situ conditions such as extreme flood in active ways emitting 24.125 GHz microwave without relying on natural lights. In South Korea, a rectangular shaped instrument named with Microwave Water Surface Current Meter (MWSCM) has been developed and commercially released around 2010, in which domestic agencies charging on streamflow observation shed lights on this approach regarding it as a potential substitute. Considering this brand-new device highlighted for efficient flow measurement, however, there has been few noticeable efforts in systematic and comprehensive evaluation of its performance in various measurement and riverine conditions that lead to lack in imminent and widely spreading usages in practices. This study attempted to evaluate the MWSCM in terms of instrumen's monitoring configuration particularly regarding tilt and yaw angle. In the middle of pointing the measurement spot in a given cross-section, the observation campaign inevitably poses accuracy issues related with different tilt and yaw angles of the instrument, which can be a conventionally major source of errors for this type of instrument. Focusing on the perspective of instrument configuration, the instrument was tested in a controlled outdoor river channel located in KICT River Experiment Center with a fixed flow condition of around 1 m/s flow speed with steady flow supply, 6 m of channel width, and less than 1 m of shallow flow depth, where the detailed velocity measurements with SonTek micro-ADV was used for validation. As results, less than 15 degree in tilting angle generated much higher deviation, and higher yawing angle proportionally increased coefficient of variance. Yaw angles affected accuracy in terms of measurement area.

• Economic and Environmental Geology
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• v.19 no.3
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• pp.231-237
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• 1986

Samples of porphyries, andesites, decites and sandstones were collected from 14 sites in order to study paleomagnetism and to determine K-Ar age in Guryongpo area. K-Ar age dating indicates that porphyries and volcanic rocks formed 41.7 and 22.7~19.4Ma, respectively. The mean direction of remanent magnetization for each site was generally well grouped after alternating field demagnetization. Both normal and reversed directions are present. The mean magnetic direction of the porphyries of Late Eocene and that of the volcanic rocks of Late Oligocene to Early Miocene have similar, easterly declinations. Overall magnetic direction is $Dm=43.8^{\circ}$, $Im=53.5^{\circ}$, ${\alpha}95=12.2^{\circ}$. the reliability of the observed paleomagnetic directions is ascertained by the presence of normal and reversed polarities. This is also conformed by the similarity of the declinations of the normal and reversed polarities. Observed easterly declinations in this area are attributed to local clockwise rotation of the land mass by approximately 40~50 degrees since early Miocene.

• ICROS
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• v.16 no.4
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• pp.35-41
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• 2010

나이퀴스트 선도와 보우드 선도는 주파수 영역에서 시스템의 안정성을 판별하는 중요한 수단이다. 본 소고에서는 나이퀴스트 판별법의 근간이 되는 편각의 원리, 그리고 이에 기초한 나이퀴스트 판별법, 이를 활용한 안정도 및 안정도 여유 판별법, 그리고 나이퀴스트 선도와 보우드 선도와의 관계 및 활용시의 장단점을 비교함으로써, 제어기 설계시 도움이 되도록 하였다.

• Archives of Hand and Microsurgery
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• v.23 no.4
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• pp.239-247
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• 2018

Purpose: We investigated occurrence of reduction loss after extension block (EB) Kirschner wire fixation or additional interfragmentary fixation (AIF) and clinical results including extension lag of the distal interphalangeal joint for treating bony mallet finger. Methods: Forty-six patients were included with a mean follow-up of 28 months (range, 12-54 months). Twenty-seven patients were treated with EB K-wire fixation (Group A) while 19 patients were treated with AIF (Group B). We checked radiologic factors, such as amount of articular involvement, volar subluxation, mallet fragment angle, reduction loss, range of motion including extension lag, and functional outcomes using Crawford's criteria. Results: Reduction loss occurred in eight patients (17%). Differences in mean extension lag, age, preoperative volar subluxation and mallet fragment angle between patients with reduction loss and those with reduction maintaining were significant. However, there were no significant differences in gender, hand dominance, amount of articular involvement, AIF, or further flexion between reduction loss and reduction maintaining. As for patterns of displacement, there was a significant relationship between gap or step-off and extension lag. Using Crawford's evaluation criteria, functional outcomes were excellent in 31, good in 10, fair in 3, and poor in 2 patients. Conclusion: Reduction loss should be careful in older age, smaller mallet fragment angle and preoperative volar subluxation.