• 대한원격탐사학회지
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• 제33권4호
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• pp.401-410
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• 2017

Estimation of snow depth using optical image is conducted by using correlation with Snow Cover Fraction (SCF). Various algorithms have been proposed for the estimation of snow cover fraction based on Normalized Difference Snow Index (NDSI). In this study we tested linear, quadratic, and exponential equations for the generation of snow cover fraction maps using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite in order to evaluate their applicability to the complex terrain of South Korea and to search for improvements to the estimation of snow depth on this landscape. The results were validated by comparison with in-situ snowfall data from weather stations, with Root Mean Square Error (RMSE) calculated as 3.43, 2.37, and 3.99 cm for the linear, quadratic, and exponential approaches, respectively. Although quadratic results showed the best RMSE, this was due to the limitations of the data used in the study; there are few number of in-situ data recorded on the station at the time of image acquisition and even the data is mostly recorded on low snowfall. So, we conclude that linear-based algorithms are better suited for use in South Korea. However, in the case of using the linear equation, the SCF with a negative value can be calculated, so it should be corrected. Since the coefficients of the equation are not optimized for this area, further regression analysis is needed. In addition, if more variables such as Normalized Difference Vegetation Index (NDVI), land cover, etc. are considered, it could be possible that estimation of national-scale snow depth with higher accuracy.

• 대한기계학회논문집A
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• 제20권7호
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• pp.2205-2212
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• 1996

In order to move the body of a walking robot translationally, and step over the obstacles, the walking robot must have at least 3 degrees of freedom for each leg. Therefore each leg of the general walking robots can be composed of 3-link system with 3 revolute joints. In this paper, the colsed form of inverse kinimatic solutions is shown for this general 3R linkage. Moreover, in order to have efficient walking volume in rough terrain, the workspace of each log is obtained considering the twist angles and the offsets in D-H parameters. When we design a walking robot, the information of the walking volume is needed for planning desired trajectories of the feet effectively. Appropriate knowledge of the walking volume can also be used to maximize linear or angular velocity of minimize power of stress. However, since it is impossible to obrain the information of walking volume in 3-D space directly from the kinematic equations, the walking volume can be searched through the edge detection algorithm using the triangle tracer with closed from inverse kinematic solutions. In this study, we present the closed form inverse kinematic solutions for 3R linkage model, and the walking volume of 6 legged walking robot which is modeled after the darking bettle, Eleodes obscura sulcipennis, through the method of edge detection for an arbitrary 2 dimensional shape using triangle tracer.

• 한국석유지질학회지
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• 제13권1호
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• pp.17-23
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• 2007

ArcGP 중력자료를 이용하여 다산과학기지가 위치한 북극 스발바드 군도의 중력특성을 파악하였다. 지형자료와 유사한 형태로 분포하는 free-air 중력이상에서 보이던 대륙 연변부의 가장자리 효과는 부게보정 후 보이지 않고, 육상지역의 CTOPO30 지형자료를 이용한 지형보정을 거친 완전 부게 중력이상에서 육상지역에서 해양지역으로 갈수록 중력이상이 증가하는 즉, 모호면의 상승과 관련이 깊은 특성이 관찰된다. 파워스펙트럼 분석을 통해 결정된 절단파수를 이용할 필터링 후 계산된 고주파 영역의 잔여이상에서 육상지역의 단층대를 따라 발달하는 특징적인 고이상대와 두꺼운 퇴적층에서 기인한 저이상대가 나타나며 해양지역 대륙사면의 최하부에서 기반 함몰 내지는 기반암 상부의 두꺼운 퇴적층과 관련이 있는 저이상대가 발달하고 있다. 역산 모델링을 통해 저주파 영역 성분에서 계산된 모호면의 기복은 스발바드 군도에서 유라시안 판 경계인 Knipovich ridge쪽으로 갈수록 상승하는 즉, 대륙주변부에서의 전형적인 특성을 보여준다.

• 한국측량학회지
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• 제33권6호
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• pp.507-516
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• 2015

Debris flow is a representative natural disaster in Korea and occurs frequently every year. Recently, it has caused considerable damage to property and considerable loss of life in both mountainous and urban regions. Therefore, It is necessary to estimate the scope of damage for a large area in order to predict the debris flow. A response model such as the random walk model(RWM) can be used as a useful tool instead of a physics-based numerical model. RWM is a probability model that simplifies both debris flows and sedimentation characteristics as a factor of slopes for a subjective site and represents a relatively simple calculation method compared to other debris flow behavior calculation models. Although RWM can be used to analyzing and predicting the scope of damage caused by a debris flow, input variables for terrain conditions are yet to be determined. In this study, optimal input variables were estimated using DEM generated from the Aerial Photograph and LiDAR data of Mt. Umyeon, Seoul, where a large-scale debris flow occurred in 2011. Further, the deposition volume resulting from the debris flow was predicted using the input variables for a specific area in which the deposition volume could not be calculated because of work restoration and the passage of time even though a debris flow occurred there. The accuracy of the model was verified by comparing the result of predicting the deposition volume in the debris flow with the result obtained from a debris flow behavior analysis model, Debris 2D.

• 한국지리정보학회지
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• 제21권3호
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• pp.127-137
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• 2018

최근 들어 UAV(무인항공기) 및 드론을 이용하여 다양한 활용기술에 대한 연구들이 이루어지고 있다. 특히, 측량분야에서는 UAV에 탑재된 디지털 카메라나 다양한 센서들을 이용하여 취득된 고해상도의 영상자료를 바탕으로 해당 지형을 모니터링하거나, 고해상도의 정사영상 및 DSM, DEM을 생성하기 위한 기술에 관한 연구들이 수행되고 있다. 본 연구에서는 UAV와 VRS-GPS를 이용하여 GCP 정합수에 따른 정확도를 분석하여 보았다. 먼저 VRS-GPS를 이용해 지상기준점을 선점한 후 UAV를 이용하여 기본고도 150m로 촬영을 실시하였으며, 646장의 영상정보를 취득하여 DSM과 정사영상을 제작하기 위해 pix4d mapper버전을 사용하여 RMSE를 분석한 결과 GCP 정합수를 5장 이상만 하여도 국가 기본도(축척 : 1/5,000) 제작 작업규정의 오차범위를 준수하고 있어 수치지도 수정 갱신 업무까지도 충분이 활용이 가능한 것으로 판단되었다.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.47-54
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• 2020

A "Scenic Site" is an official heritage category legally defined as a "scenic site of outstanding artistic value with excellent scenic views." However, the subjective interpretation of the term causes several problems. This study suggested a systematic, organized process of designating a listed area as a scenic site after careful and detailed quantitative and qualitative analysis. Indicators were identified for each of the two analyses, and then scored and weighted. Quantitative indicators were distributed within 5 points for each indicator. Water, which is a natural indicator, based on distance from river boundaries. Forest landscapes were assigned in consideration of forest physiognomy and age class. Land use was allocated in consideration of land cover type and, in case of development site, '-' score was assigned. Cultural heritage conservation area, which is historical and cultural indicator, was distributed by distance within a maximum of 500 meters. Visibility, an indicator of landscape value, was assigned according to the frequency of visibility. The weight of each indicator was calculated by considering the value of each item. The weight of distribution of cultural resources is relatively high, while other items were set the same. In case of land use, however, '-' score was given according to the grade. Qualitative indicators, on the other hand, were considered terrain, landscape zone, ownership, intellectual boundary, and land category. The applicability of the proposed process and method was examined by applying the existing methods and criteria used for designating scenic spots. Opinions of subject-matter experts were incorporated in the identification of the indicators and in the result review stage. In the future, it is necessary to apply this method while designating scenic sites so as to establish an objective, scientific designation process.

• 한국환경과학회지
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• 제15권5호
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• pp.417-430
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• 2006

We focused on improvement in simulation of wind fields for the complex coastal area. Local Analysis and Prediction System(LAPS) was used as a data assimilation method to improve initial conditions. Case studies of different LAPS inputs were performed to compare improvement of wind fields. Five cases have been employed : I) non data assimilation, II) all available data, III) AWS, buoy, QuikSCAT, IV) AWS, buoy, wind profiler, V) AWS, buoy, AMEDAS. Data assimilation can supplement insufficiency of the mesoscale model which does not represent detailed terrain effect and small scale atmospheric flow fields. Result assimilated all available data showed a good agreement to the observations rather than other cases and estimated veil the local meteorological characteristics including sea breeze and up-slope winds. Result using wind profiler data was the next best thing. This implies that data assimilation with many high-resolution sounding data could contribute to the improvements of good initial condition in the complex coastal area. As a result, these indicated that effective data assimilation process and application of the selective LAPS inputs played an important role in simulating wind fields accurately in a complex area.

• 대한공간정보학회지
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• 제13권4호
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• pp.27-32
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• 2005

DEM(수치표고모형) 자료는 도시모델링, 홍수 예측, 경사 및 향 분석 등과 같은 GIS의 다양한 분야에 필요하며, 주로 수치지도, 항공사진, 고해상도 위성영상 등을 이용해서 제작해 왔다. 그러나 최근에는 LiDAR 데이터로부터 DEM을 제작하는 것이 효율적이고 정확도가 높기 때문에 이에 대한 연구가 활발히 이루어지고 있다. LIDAR 원 데이터로부터 건물, 수목 등의 개체를 제거하여 DEM을 생성하는 과정을 필터링(filtering)이라고 하는데, 대부분의 연구에서는 필터의 크기를 비롯한 몇 가지 파라미터가 필요하고 그 값을 바꿔가면서 반복연산을 수행해야 하는 경우가 많다. 본 연구에서는 비지면점으로 인식된 점의 높이값을 이웃 지면점의 높이값으로 대체하고 대체된 값을 다음 연산에 반영함으로써 개체의 크기에 대한 사전 지식 없이 다양한 크기의 개체를 제거할 수 있는 필터링 기법을 제안하였다. 실험 결과 본 연구에서 제안한 방법은 다양한 크기의 개체가 존재하는 경사가 심한 지형에 대하여 우수한 필터 링 결과를 보여주었다.

• 한국정밀공학회지
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• 제24권7호
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• pp.90-97
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• 2007

This paper describes the development of 6-axis force/moment sensor considered adult weight far an intelligent foot of humanoid robot. In order to walk on uneven terrain safely, the foot should perceive the applied forces Fx, Fy, Fz and moments Mx, My, Mz to itself and control the foot using the forces and moments. The applied forces and moments should be measured from a 6-axis force/moment sensor attached to the foot, which is composed of Fx sensor, Fy sensor, Fz sensor, Mx sensor, My sensor and Mz sensor in a body. Each sensor should get the deferent rated load, because the applied forces and moments to foot in walking are deferent. Therefore, one of the important things in the sensor is to design each sensor with the deferent rated load and the same rated output. In this paper, a 6-axis force/moment sensor (rated load of Fx and Fy are 500Nm and Fz sensor is 1000N, and those of Mx and My are 18Nm, Mz sensor is 8Nm) for perceiving forces and moments in a humanoid robot's foot was developed using many PPBs (parallel plate-beams). The structure of the sensor was newly modeled, and the sensing elements (plate-beams) of the sensor were designed using by ANSYS software (FEM (Finite Element Method) program). Then, a 6-axis force/moment sensor was fabricated by attaching strain-gages on the sensing elements, and the characteristic test of the developed sensor was carried out. The rated outputs from FEM analysis agree well with that from the characteristic test.

• 아시안잔디학회지
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• 제20권1호
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• pp.93-105
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• 2006

최근 많은 수의 골프장 건설로 인하여 국토의 상당면적이 원지형의 변화 또는 파괴되고 있으며 주변 생태계가 급속한 변이를 겪고 있다. 골프코스 건설을 위해서는 정밀하고 효율적인 설계를 요하지만 기존의 통상적 설계방식으로는 사업의 방대성으로 인한 설계자료의 처리에 한계를 가지고 있었다. 특히 공사 후의 경관 변화에 대한 예측이나 환경영향 저감대책에 대하여 적절한 대안을 제시할 적절한 수단이 없었다. 따라서 이러한 문제점을 해결하기 위하여 지형정보시스템(GIS)을 골프코스 설계에 적용하여 건설에 따른 물리적 영향을 최소화시킬 수 있는 친환경적인 골프코스 설계 기법개발에 대하여 연구하였다. 연구된 내용은 지형정보시스템을 기초자료입력 단계에서부터 최종 성과물 단계까지 적용시켜 전 설계과정을 전산화하며, 부수적으로 골프 경기의 기능적 효과 증대 토지이용의 적정성, 코스유지 관리의 용이성 등을 사전 검토할 수 있는 친환경적 전산설계기법을 개발 연구하였다.