• ETRI Journal
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• 제15권3_4호
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• pp.27-34
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• 1994

There have been traditional approaches to model radio propagation path loss mechanism both theoretically ad empirically. Theoretical approach is simple to explain and effective in certain cases. Empirical approach accommodates the terrain configuration and distance between base station and mobile unit along the propagation path only. In other words, it does not accommodate natural terrain configuration over a specific area. In this paper, we propose a spatial prediction technique for the mobile radio propagation path loss accommodating complete natural terrain configuration over a specific area. Statistical uncertainty analysis is also considered.

• 한국도로학회논문집
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• 제13권4호
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• pp.221-229
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• 2011

도로 설계는 자연 지형에 순응하도록 선형을 결정함으로써 경제적이며 환경적인 피해가 최소화되는 도로 건설이 이루어지도록 할 필요가 있다. 현 도로설계기준은 지형을 평지와 산지로만 구분하고 있으나 국토의 25.8%가 구릉지이며 미국이나 호주 등 선진국의 경우도 지형을 평지, 구릉지, 산지로 세분화하여 자연 지형에 최대한 부합되는 설계를 유도하고 있음을 감안 시 구릉지를 포함한 세분화된 기준이 필요하다. 본 연구는 원지반의 기복량을 지표로 세 가지 독립된 지형간의 구분 기준을 정량적으로 제시하였다. 세분화된 지형 정의를 전제로 지형을 구분할 수 있는 방안에 대한 개념적 틀을 세우고 이를 도로설계 사례분석 등을 토대로 검토하였다. 연구 결론으로, 평지는 설계 단위구간(1km) 내 지반고 최고점과 최저점의 차이가 40m 미만, 구릉지는 40~60m 이내, 산지는 60m를 초과하는 것으로 제안하였다.

• 한국게임학회 논문지
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• 제15권6호
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• pp.171-182
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• 2015

지형에 대한 기존의 침식 시뮬레이션은 주로 소규모의 지형 변화에 초점을 맞추고 있다. 이 논문에서는 물에 의한 침식과 열적 침식과정을 결합하여 강의 네트워크와 산들로 이루어진 자연스러운 대규모의 지형을 형성하는 방법을 제안한다. 물의 흐름에는 shallow water 시뮬레이션의 파이프 모델을 사용하며, 강물의 줄기가 쉽게 형성되게 하기 위해 속도에 의존하는 침식을, 강줄기 주변에 V자형 골짜기가 생성되게 하기 위해 열적 침식을 적용한다. 시뮬레이션 결과 $K_c$(퇴적물 수용상수)와 $K_v$(속도의존 침식강도)의 값이 적당한 범위에 있을 때만 목적한 모양의 지형이 생성되며, 이렇게 생성된 대표적인 자연스러운 모양의 지형을 예시한다. 또한 기존의 열적 침식 방법의 개선과 $K_c$가 큰 값일 때 발생하는 문제점을 해결할 방안을 제시한다.

• 한국도로학회논문집
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• 제16권6호
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• pp.191-198
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• 2014

PURPOSES : Safety consciousness can be the first factor to hinder the acceptance of design alternative, which moderates the applied design criteria in order to adapt the road to the natural terrain condition. METHODS : The method which enables to check the safety of design alternative by using design consistency concept is suggested. The method is based on the linked or interactive analysis between terrain and road alignment. Real design example is considered as a guide how to apply the method and the analysis result is discussed with the future research. RESULTS : Suggested method can be used for designers as a tool to review their design outputs can be safe as much as the original design. So, designers have the more objective judgement on their designs and have the confidence on their designs. CONCLUSIONS : The method is expected to be used as a tool to see the safety consciousness in an objective view, so any possible conflicts between designers and design-related personnels caused by the terrain-oriented design can be solved.

• 한국해양공학회지
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• 제16권6호
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• pp.37-43
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• 2002

The calculation of earthwork plays a major role in the plan or design phase of many civil engineering projects, such as seashore reclamation; and thus, it has become very important to improve upon its accuracy. There have been common drawbacks to earlier methods of ground profiling, such as dialing with sharp corners or the grid points of any tow straight lines. In this paper, we prepose an algorithm for finding a terrain surface using the natural boundary conditions and the both direction spline method, which interpolates the given three-dimensional data by using spline. As a result of this study, the algorithm of the proposed two methods to estimate pit excavation volume should provide a better accuracy than Spot height, Chambers, Chen, or Lin method. Also, the mathematical model mentioned offers maximum accuracy in estimating the volume of a pit excavation.

• 제어로봇시스템학회논문지
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• 제14권9호
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• pp.909-915
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• 2008

Recently, the interests in the development and application of unmaned robots are increasing in various fields including surveillance and reconnaissance, planet exploration, and disaster relief. Unmaned robots are usually controlled from distance using radio communications but they should be equipped with an autonomous travelling function to cope with unexpected terrains and obstacles. This means that they should be able to evaluate terrain's characteristics quantitatively using mounted sensors so as to traverse harsh natural terrains autonomously. For this purpose, this paper presents a method for extracting terrain information, that is, slope and roughness from elevation maps as a prior step of traversability analysis. Slope is extracted using the curve fitting based on the least squares method and roughness using three metrics and their weighted average. The effectiveness of the proposed method is verified on both a fractal map and the world model map of a real terrain.

• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2008년도 춘계학술대회 학술발표회 논문집
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• pp.233-236
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• 2008

Recently, the development and application of unmaned robots are increasing in various fields including surveillance and reconnaissance, planet exploration and disaster relief. Unmaned robots are usually controlled from distance using radio communications but they should be equipped with autonomous travelling function to cope with unexpected terrains and obstacles. This means that unmanned robots should be able to evaluate terrain's characteristics quantitatively using mounted sensors so as to traverse harsh natural terrains autonomously. For this purpose, this paper presents an algorithm for extracting terrain information from elevation maps as an early step of traversability analysis. Slope and roughness information are extracted from a world terrain map based on least squares method and fractal theory, respectively. The effectiveness of the proposed algorithm is verified on both fractal and real terrain maps.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.389-392
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• 2004

Classification of Earth natural components within a full polarimetric SAR image is one of the most important applications of radar polarimetry in remote sensing. In this paper, the unsupervised classification algorithms based on the combined use of the polarimetric processing technique such as the target decomposition and statistical complex Wishart classification method are evaluated and applied to vegetated terrain in Jeju volcanic island.

• 제어로봇시스템학회논문지
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• 제18권3호
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• pp.251-257
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• 2012

Unmanned ground vehicles have important military, reconnaissance, and materials handling application. Many of these applications require the UGVs to move at high speeds through uneven, natural terrain with various compositions and physical parameters. This paper presents a framework for high speed autonomous navigation based on the integrated real time traversability. Specifically, the proposed system performs real-time dynamic simulation and calculate maximum traversing velocity guaranteeing safe motion over rough terrain. The architecture of autonomous navigation is firstly presented for high-speed autonomous navigation. Then, the integrated real time traversability, which is composed of initial velocity profiling step, dynamic analysis step, road classification step and stable velocity profiling step, is introduced. Experimental results are presented that demonstrate the method for a $6{\times}6$ autonomous vehicle moving on flat terrain with bump.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.186-188
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• 2003

Rail Route Alignment in hilly terrain is a difficult task to implement as several natural constraints poses threat to the safety and stability of the alignment. The conventional methods followed to find out the final location survey or the feasibility analysis for alignment is time taking consuming. Some times, due to inaccessibility of the terrain it becomes impossible to carry out such works. The construction works in hilly terrain, which are associated with the proposed alignment, are not same as carried out in plane areas due to a vast contrast between the two areas. Different geological structures such as faults, thrusts, synclines and anticlines are a big problem to carry out normal construction practices. Thus for a safe and stable railway route in the unstable hilly areas, it is required to carry out the feasibility analysis of the proposed alignment to assist the policy makers for a successful implementation of the alignment. In the present work Remote Sensing and GIS has been successfully used to carry out geological feasibility and slope stability analysis for rail route alignment work.