• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2004년도 춘계학술발표회
• /
• pp.904-909
• /
• 2004

The study area adjoins with Yangsan fault in Sangbuk-myeon, Samsam-ri, Kyongsang-namdo and consist of the natural steep slope. After drawing data layer which have altitude by using digital topography data, it is converted to lattice DEM of $10m{\times}10m$ size. From this, gradient map of unit lattice, slant direction map and shadow relif map are made. Using flow apportioning algorithm, upper slope contributing area and wetness index by established lattice can be calculated. Area that have high wetness index shows lineament structure of northwest-southeast direction, and this agrees with shear fracture system. The result of electricity specific resistance survey in the study area shows that area of high wetness index has low electricity specific resistance anomaly. That is, wetness index conforms with distribution of fractured zone that accompanied chemical weathering of rock. Therefore, wetness index can be used as the method of detecting fractured zones and judging the stability of the area.

• 한국산학기술학회논문지
• /
• 제11권5호
• /
• pp.1592-1596
• /
• 2010

IGZO (indium gallium zinc oxide) 박막트랜지스터는, 활성층 채널의 폭과 길이의 비가 고정된 경우에도, 채널 길이가 길어지면 게이트전압에 대한 드레인 전류의 특성곡선이 양의 전압 방향으로 이동하고 전계효과이동도는 낮아졌다. 채널의 길이와 폭이 고정된 상태에서는, 드레인이 전압 높은 경우에 전계효과이동도가 낮고 문턱아래 기울기가 큰 특성을 보였다. 이러한 현상은 IGZO 채널층의 일함수가 커서 소스/드레인 전극과 채널층의 접합부 띠굽음이 규소반도체의 경우와 반대방향으로 나타나는 것에 기인하는 것으로 해석된다.

• 대기
• /
• 제25권4호
• /
• pp.591-600
• /
• 2015

We have analyzed wind and eddy covariance data collected within roughness sublayer over sloping terrain. The study site is located on non-flat terrain with slopes in both south-north and east-west directions. The surface elevation change is smaller than the height of roughness element such as building and tree. This study examines the directional wind shear for data collected at three levels in the lowest 10 m in the roughness sublayer. The wind direction shear is caused by drag of roughness element and terrain-induced motions at this site. Small directional shear occurs when wind speed at 10 m is strong and wind direction at 10 m is southerly which is the same direction as upslope flow near surface at this site during daytime. Correlation between vertical shear of lateral momentum and lateral momentum flux is smaller over steeply sloped surface compared to mildly sloped surface and lateral momentum flux is not down-gradient over steeply sloped surface. Quadrant analysis shows that the relative contribution of four quadrants to momentum flux depends on both surface slope and wind direction shear.

• 한국정밀공학회지
• /
• 제34권4호
• /
• pp.259-264
• /
• 2017

Spectrally resolved interferometry (SRI) is an attractive technique to measure absolute distances without any moving components. In the spectral interferogram obtained by a spectrometer, the optical path difference (OPD) can simply be extracted from the linear slope of the spectral phase. However, SRI has a fundamental measuring range limitation due to maximum and minimum measurable distances. In addition, SRI cannot distinguish the OPD direction because the spectral interferogram is in the form of a natural sinusoidal function. In this investigation, we describe a direction determining SRI and propose the optimal conditions for determining OPD direction. Spectral phase nonlinearity, caused by a dispersive material, effects OPD direction but deteriorates spectral interferogram visibility. In the experiment, various phase nonlinearities were measured by adjusting the dispersive material (BK7) thickness. We observed the interferogram visibility and the possibility of direction determination. Based on the experimental results, the optimal dispersion conditions are provided to distinguish OPD directions of SRI.

• Journal of Biosystems Engineering
• /
• 제2권1호
• /
• pp.33-48
• /
• 1977

Transporting agricultural products and the other material by the two-wheel-tractor (power-tiler)and trailer system may be one of its most widely used farming functions.The safety and hitching load for all the previaling performing conditions may be the general concern over the operation of the tiller-trailer system. In this study, a mathematical model to determine the static and dynamic forces excerting on the hitch point were developed . Based on the analysis of the model and the field measurements. the limiting hitching load and critical slope were analyzed. The results of the study are summarized as follows ; 1) The limit angle of slope land for the safety steering that two-wheel tractor-single axle trailer system was able to transport agricultural products was the direct angle (${\gamma}$) = 8 ; the cross angle$\beta$) 15 ; and it was decreased in accordance with the increase of carrying load ($W_4). 2) The critical velocity for safe operation in case of running on downward hill road was about 1.08m/sec. 3) The limiting carrying load for the safe steering was W$_4$=600kg. The degree of the safe steering for different braking methods was given in order as follows ; Simulataneous braking the tractor and trailer , braking the trailer only, and braking tractor only. 4) Among the three components of impact loads excerting on the hitch point, the component in the lateral direction ($P_{Vy}$) was near zero in spite of increase of hitching load ($W_4) , while the components in the other two mutually perpedicular directions ($P_{Vx}$ and ($P_{Vz}$) ) had larger values in horizontal plane than those in the slope lands. 5) Moment of forces on the lateral direction (M$y$) had the largest value among the three components of impact moment acting on the hitch point, however all the components were sharply increased in accordance with the increase of hitching loads ($W_4. Three components of the moment were the negative values.

• 로봇학회논문지
• /
• 제9권3호
• /
• pp.147-153
• /
• 2014

In this paper, we proposed a new algorithm of the guidance line extraction for autonomous weeding robot based on infrared vision sensor in wet paddy. It is the critical process for guidance line extraction which finds the central point or area of rice row. In order to improve accuracy of the guidance line, we are trying to use the morphological characteristics of rice that the direction of rice leaves have convergence to central area of rice row. Using Hough transform, we were represented the curved leaves as a combination of segmented straight lines on binary image that has been skeletonized and segmented object. A slope of the guidance line was gotten as calculate the average slope of all segmented lines. An initial point of the guidance line was determined that is the maximum pixel value of the accumulated white columns of a binary image which is rotated the slope of guidance line in the opposite direction. We also have verified an accuracy of the proposed algorithm by experiments in the real wet paddy.

• International Journal of Precision Engineering and Manufacturing
• /
• 제9권3호
• /
• pp.27-32
• /
• 2008

This paper describes a contact atomic force microscope (AFM) that can be used for high-speed precision measurements of microstructured surfaces. The AFM is composed of an air-bearing X stage, an air-bearing spindle with the axis of rotation in the Z direction, and an AFM probe unit. The traversing distance and maximum speed of the X stage are 300 mm and 400 mm/s, respectively. The spindle has the ability to hold a sample in a vacuum chuck with a maximum diameter of 130 mm and has a maximum rotation speed of 300 rpm. The bandwidth of the AFM probe unit in an open loop control circuit is more than 40 kHz. To achieve precision measurements of microstructured surfaces with slopes, a scanning strategy combining constant height measurements with a slope compensation technique is proposed. In this scanning strategy, the Z direction PZT actuator of the AFM probe unit is employed to compensate for the slope of the sample surface while the microstructures are scanned by the AFM probe at a constant height. The precision of such a scanning strategy is demonstrated by obtaining profile measurements of a microstructure surface at a series of scanning speeds ranging from 0.1 to 20.0 mm/s.

• 한국지반공학회논문집
• /
• 제28권12호
• /
• pp.123-131
• /
• 2012

최근에 발생한 아이티지진, 칠레지진의 지진파 기록에서 일반적으로 비탈면 안정해석에서 무시되었던 수직방향 지진가속도 성분이 크게 나타났다. 특히, 수직방향 지진성분은 진원이 내륙에 위치한 경우 더욱 뚜렷하게 나타난다. 그러므로 설계에 수직방향 지진성분을 고려하지 않은 지반 구조물들은 많은 인명과 재산 피해를 가져올 수 있다. 따라서, 본 연구는 지진계수비에 따른 수평방향 항복지진계수의 하계해를 산정하였고, 비탈면 안정성에 미치는 영향을 평가하였다. 또한, 한계상태 수직방향 지진계수의 방향(상향, 하향)을 결정할 수 있는 관계식을 제안하였다.

• 지질공학
• /
• 제22권1호
• /
• pp.1-13
• /
• 2012

본 연구에서는 퇴적암지역에서 발달하는 지질구조들이 비탈면의 안정성에 어떠한 영향을 미치는지를 이해하고자 하였다. 연구지역과 같이 퇴적암지역 비탈면의 경우, 도로 양쪽의 비탈면이 층리의 경사방향에 따라 매우 다른 양상을 보인다. 또한 단층대가 존재하는 경우에는 보강공사가 완료된 후에도 지속적인 파괴가 관찰되고 있었다. 하지만 대부분의 대규모 단층에서 비탈면 안정성 조사 시 단층대를 정확하게 인지하기 어려워 새로운 누적절리밀도를 통한 단층대 인지방법을 제안하였다. 또한 최근 대규모 공사로 인하여 많은 비탈면들이 다면비탈면의 형태로 나타나는 경우가 많다. 이 경우 일정한 주향을 가진 대표비탈면들의 방향에 따라 구간을 설정하고, 이를 바탕으로 비탈면 안정성 분석을 실시하여, 각 구간에 따라 다른 비탈면 안정성 평가가 이루어져야 하는 예를 보여주었다. 따라서 퇴적암지역에서의 비탈면설계 시 층리와 불연속면의 방향 그리고 이들 사이의 상관관계 등 지질구조들의 발달특성을 잘 고려한다면 공사단계에서도 작업의 효율을 높일 수 있고, 공사 후에도 비탈면의 안정성을 높일 수 있을 것으로 판단된다.

• 한국터널지하공간학회 논문집
• /
• 제2권2호
• /
• pp.50-61
• /
• 2000

터널의 갱구부는 터널에서 3차원 거동을 가장 뚜렷하게 보이는 부분이며 대체로 풍화가 진행되어 거의 토사화되어 있는 취약한 암반에 시공됨에 따라 비탈면은 잠재적인 활동체가 되게 된다. 터널 갱구부 비탈면에서 안정에 위해되는 요인이 발생했을 경우 파괴가 급속히 진행되어 대형사고로 이어질수 있으므로 특별한 안정화 대책이 필요하여 경제적으로 큰 부담이 된다. 이를 해결하기 위한 방안으로 갱구부 비탈면을 수평 아치형으로 굴착하게 되면 굴착량이 줄어서 경제적이고 자연훼손이 줄어들며 보다 안전하고 아름다운 형상을 기대할 수 있다. 그러나 인식부족으로 인하여 이와 같은 시도는 거의 이루어지지 않고 있어서 면벽식 갱구부가 보편화 되어 있는 실정이다. 본 연구에서는 아치형 갱구부 비탈면의 이점을 알아보기 위하여 3차원 수치해석을 ㄷ형과 아치형 비탈면에 대하여 각각 수행하여 그 결과를 서로 비교하였으며 터널 굴진과 암반강성에 따른 갱구부 비탈면의 안정성은 비탈면에서 발생되는 최대전단변형율과 막장면에서 터널굴진에 따른 소성접근도를 분석하여 검토하였다.