• Journal of the Optical Society of Korea
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• 제19권2호
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• pp.144-148
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• 2015

An alternative description for the Gaussian image plane (GIP) of an optical system for a given object is presented, which applies to both aberration-free and non-aberration-free systems. We extend the definition of transverse magnification (TM) to the image plane (IP) displaced from the GIP and find that the TM depends linearly on the locations of both an aperture stop placed in front of the system and the IP. Hence, we redefine the GIP as the location at which the slope of the TM variance changes sign. The definition is deterministic and self-consistent and, therefore, no other parameters or measurements are needed. The derivation of this definition using a set of paraxial ray tracings and supporting experimental data for a thick bi-convex lens system is presented.

• Water Engineering Research
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• 제3권3호
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• pp.155-162
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• 2002

This study presents the theoretical approach for volume concentration, velocity profile, and granular discharge on the fluid-granule mixed flow downstream of the scour hole at the outlet of the hydraulic structure. Concept of dilatant model was applied for the stress-strain relationships of fluid-granule mixed flow since the flow downstream of the scour hole corresponds to debris flow, where momentum transfers through particle collisions. Mathematical formulations were derived using momentum equation and stress-strain relation of the fluid-granule mixture. Velocity profile under the assumption of uniform concentration over flowing layer showed the downward convex type. Deposition angle of downstream hump was found to be a function of an upstream slope angle, a dynamic friction angle and a volume concentration irrespective of flow itself, Granular discharge and the overflow depth were obtained with given values of inflow rates. Experimental results showed relatively good agreements with theoretical ones.

• 한국광학회:학술대회논문집
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• 한국광학회 1988년도 광학 및 양자전자학 워크샵
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• pp.135-144
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• 1988

1-GW Iodine photodissociation Laser (λ=1.315${\mu}{\textrm}{m}$)is focused to generate the continuum x-ray radiation at titanium(z=22)target. A piced of aluminum(360 )-mylar(8${\mu}{\textrm}{m}$) film is used to isolate the soft X-ray radiation emitted. Convex-xurved mica crystal spectrometer is used to obtain the soft x-ray spectra from the laser titanium target plasma and the slope of continum X-ray spectra are found to show two different different electron effective temperaturres, 0.11keV and 7.1KeV. We compare the two temperature result with the foil absorption method.

• 지질공학
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• 제30권3호
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• pp.289-302
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• 2020

2016년 경상남도 하동군 땅밀림 지역의 지하구조와 미끄럼사면을 파악하기 위해 지구물리탐사(전기비 저항, 탄성파 굴절법, 시추공 영상촬영)와 사면안정해석을 실시하였다. 시추조사와 탄성파속도로 해석된 사면의 지층 및 지하구조는 20여 m의 두터운 퇴적층 밑에 구간에 따라 1 m보다 얇은 풍화암 및 연암이 각각 분포한다. 지표지질조사를 통하여 관찰된 인장균열의 지표흔적을 기준으로 시추공 BH-2에서 영상촬영을 수행하여 확인된 집중 파쇄대의 분포는 지하수면과 쌍극자배열 전기비저항 단면에서 해석된 활동연약대의 깊이와 잘 부합한다. 기반암 표면의 고비저항 돌출부는 연약대의 하부 진행을 막는 일종의 자연적인 받침대 역할을 하여 이것을 경계점으로 활동면이 미끄러지고 약간 위로 올라가는 휘어진 파괴면을 수반하는 땅밀림의 특성을 설명해준다. 활동연약대에 대한 사면안정해석에서 지하수면의 변동시켜가며 건기와 우기의 안전율을 계산한 결과 우기에 해당되는 0.89의 낮은 값은 지하수로 완전포화된 물질에 기인하는 바 조사지역의 사면은 호우 시 불안정한 사면으로 해석된다.

• 한국지반신소재학회논문집
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• 제17권1호
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• pp.95-109
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• 2018

최근 보강토 공법은 구조적으로 안정성이 우수하고 경제성이 뛰어나 콘크리트 옹벽을 대체하는 공법으로 많이 사용되고 있으며, 옹벽뿐만 아니라 기초, 사면, 도로 등에 그 적용 범위가 다양하다. 그러나, 우수와 같은 침투수로 인해 전면 벽에서 충분한 안정성을 확보하지 못하여 붕괴, 배부름 현상 등의 피해가 발생할 수 있고, 특히 곡선부에서는 응력집중 현상에 의해 전면 벽의 균열 등의 문제가 추가적으로 일어날 수 있다. 이는 보강토 옹벽 곡선부에 대한 정확한 설계 기준이 미흡하고 부실시공을 하는데 원인이 있다고 할 수 있다. 따라서 본 연구에서는 보강토 옹벽의 피해사례를 통해 문제점을 파악하고 유한요소 수치해석을 통해 보강토 옹벽 설계를 위한 기초 연구로서, 옹벽의 형상(볼록형, 오목형)에 따른 직선부와 곡선부의 거동을 비교 분석하였다.

• 대한치과보철학회지
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• 제31권4호
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• pp.549-564
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• 1993

The purpose of this study was to research the condylar path and the anterior angle of glenoid fossae and classify the patterns of condylar path. Thirty male and female dental students with normal occlesion and masticatory system ranging in age from 21 to 30, without present symptoms and an)r history of TM joint disturbance, were selected for this study. Transcranial radiographs of TM joints under mandibular lateral movement were obtained. By the computer analysis on the radiographs, the angle of posterior slope of articular eminance, the sagittal condylar guidance angie, condylar movement patterns and the height of glenoid fossa was measured respectively, and studied their interrelationship comparatively. The results obtained were as follows : 1. The total distance of condylar movement on balancing side during mandibular lateral movement was 4.55mm for Lt. and 4.78mm for Rt. when mandible moved from C.R. to canine to canine relation and 7.86mm for the Lt. and 8.10mm for the Rt. when mandible moved from C.R. to 7.5mm. 2. The horizontal distance of condylar movement on balancing side during mandibular lateral movements was 3.16mm for the Lt. and 3.52mm for the Rt. when mandible moved from C.R. to canine to canine relation and 6.10mm for the Lt. and 6.30mm for the Rt. when mandible moved from C.R. to 7.5mm. 3. The sagittal condylar guidance angle on balancing side during mandibular lateral movements was $45.96^{\circ}$ for the Lt. and $43.22^{\circ}$ for the Rt. when mandible moved from C.R. from canine to canine relation and $41.14^{\circ}$ for the Lt. and $39.77^{\circ}$ for the Rt. when mandible moved from C.R. to 7.5mm. 4. The height of glenoid fossa was 8.23mm for the Lt. and 7.80mm for the Rt. and the angle of posterior slope of articular eminence was $38.30^{\circ}$ for the Lt. and $38.79^{\circ}$ for the Rt. by method-A and $55.61^{\circ}$ for the Lt. and $55.64^{\circ}$ for the Rt. by method-B. 5. The sequence of the frequency of condylar movement patterns on balancing side during mandibular lateral movement were concave type(30 cases), convex type(16 cases), reverse S shape curve(9 cases) and S shape curve(5 cases) when mandible moved from C.R. to canine to canine relation and concave type(27 cases), 5 shape curve(13 cases), convex type(11 cases) and reverse S shape curve(9 cases) when mandible moved from C.R. to 7.5mm.

• 농업생명과학연구
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• 제44권4호
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• pp.9-20
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• 2010

전라북도지역을 산사태 발생지 182개소를 대상지로 선정하여 강우의 특성 및 다양한 환경인자 별로 조사하여 산사태발생 특성을 분석하였다. 전라북도 지역을 산사태 발생 수는 총 182개소였으며, 산사태 발생 평균면적은 $1,859m^2$, 평균 발생토사량은 $4,41m^3$, 평균 길이와 폭은 각각 139m와 13m로 나타났다. 산림환경인자별 산사태 발생 빈도가 높은 인자는 사면경사도 $21{\sim}30^{\circ}$, 북쪽사면, 해발 401m~500m 이상, 종단사면 (오목), 횡단사면 (오목), 침엽수, 화성암, 토심은 15cm이하, 하천차수는 1차, 사면위치 (산복), 산사태 유형 (선상), 임종 (인공림), 수고 11m~15m, 흉고직경 중경목(17cm이상)에서 산사태 발생이 높은 것으로 조사되었다. 전라북도 지역의 산사태 발생면적과 산림환경인자와의 상관을 분석한 결과는 횡단사면 (볼록), 사면위치 (산정), 표고 (501이상), 임상 (침엽수), 모암 (퇴적암), 흉고직경 (17cm이상)과는 1% 수준 내에서 정의상관관계를 보였고, 경사 ($31{\sim}40^{\circ}$), 모암 (화성암), 흉고직경 (6~16)에서 1% 수준 내에서 부의 상관관계를보였다.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.809-815
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• 2020

A number of investigations and studies have been conducted in various fields regarding the sediment disasters of Mt. Woomyeon that occurred in July 2011. We collected and compared the topographic information of the general points where debris flows did not occur and the collapse points where the debris flow occurred in order to find out the characteristics of the collapse points in Woomyeon mountain. The collected topographic information is altitude, curvature, slope, aspect and TPI(topographic position index). As a result of comparison, there were relatively many collapse points at an altitude of 210m to 250m, and at a slope of 30° to 40°. In addition, the risk of collapse was low in a cell where the curvature was close to 0, and the risk was higher in concave terrain than in convex terrain. In the case of TPI, there was no statistical difference between the general points and the collapse points when the analysis radius was larger than 200m, and there was a correlation with the curvature when the analysis radius was smaller than 50m. In the case of debris flows that are affected by artificial structures or facilities, there is a possibility of disturbing the topographic analysis results. Therefore, if a research on debris flow is conducted on a mountain area that is heavily exposed to human activities, such as Woomyeon mountain, diversified factors must be considered to account for this impact.

• 한국지역지리학회지
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• 제9권4호
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• pp.413-424
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• 2003

이 연구의 목적은 한국의 영남지방에 있는 4개 전통취락의 입지를 지형적인 관점에서 해석하는 것이다. 이를 위해 GIS 기법을 이용하여 취락의 사면 경사도, 사면향, 하천과의 관계를 계량적으로 분석하였다. 특히 전통취락의 입지에 담겨있는 풍수적 사고와 택리지의 복거론적 지형인식이 현대의 지형분석적 입장에서는 어떤 의미를 가지며 그것이 시사하는 점이 무엇인지를 검토해 보았다. 그 결과 유곡은 계곡분지의 산록부 천전은 구룡지 말단부에 입지한다. 하회는 곡류하천 범람원의 볼록한 자연제방에 입지하고, 양동은 구릉지에 입지하고 있다. 가옥들은 대체로 남향과 남동향, 남서향이 많지만, 하회는 모든 사면으로 분포하는 것이 특징이다. 또한 4지역은 하상비고 $10{\sim}20m$ 범위에 입지하는데, 이 하상비고는 수해에 대비한 안전고도임을 알 수 있다. 이처럼 과거 풍수적 관점에서 명당이라 지칭해 온 영남지방 4대 전통취락의 입지는 현대의 주거입지론적 측면에서도 우수한 지형조건을 갖추고 있는 것으로 판단된다.

• 한국조경학회지
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• 제26권3호
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• pp.162-177
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• 1998

Conentionally, LS factor for the USLE suggested by Wischmeier has been computed manually on topographic maps based on one dimensional approach. But outcomes of the equation could be severely affected by the convergence and divergence of surface runoff at complex terrains. Thus the objective of this research are to develop a method to automatically compute LS factor based on the multiple flow algorithm, and to test the accuracy of this method by comparing outcomes of this method to previous measurements or estimations of soil erosion. The program for the automatic calculation of LS factor was developed by utilizing Fox Pro 4.5, and outcomes of the program is designed to input to IDRISI. The accuracy test of LS factor was carried out by comparing the actual measurements of soil loss at two test sites in and around of Suwon. The calculated volume of soil erosion at Buju mountain, Mokpo, was also compared to the outcome of a previous research based on the LS factor calculated by the conventional onedimensional approach. The outcomes of this research are as follows. First, the computed L based on the multiple flow algorithm for concae slopes are greater than those of convex slopes,. Second, the estimated soil loss based on this method at the test site in Mokpo is much greater than the outcomes based on the conventional one-dimensional approach. It can e concluded that the application of this automatic calculation method of LS factor can improve the accuracy of USLE and facilitate soil erosion prevention methods.