• Journal of the Korean Geographical Society
• /
• v.39 no.4
• /
• pp.495-513
• /
• 2004

The shape of land surface work as a cradle for various environmental processes and human activities. As spatially distributed process modelings become increasing important in current research communities, a classification system that delineates land surface into characteristic geomorphological units is a pre-requisite for sustainable land use planning and management. Existing classification systems are either morphometric or generic, which have limitations to characterize continuous ecological processes over the landscape. A new classification system was developed to delineate the land surface into different geomorphological units from Digital Elevation Models(DEMs). This model assumes that there are pedo-geomorphological units in which distinct sets of hydrological, pedological, and consequent ecological processes occur. The classification system first divides the whole landsurface into eight soil-landscape units. Possible energy and material nows over the land surface were interpreted using a continuity equation of mass flow along the hillslope, and subsequently implemented in terrain analysis procedures. The developed models were tested at a 12$\textrm{km}^2$ area in Yangpyeong-gun, Kyeongi-do, Korea. The method proposed effectively delineates land surface into distinct pedo-geomorphological units, which identify the geomorphological characteristics over a large area at a low cost. The delineated landscape units mal provide a basic information for natural resource survey and environmental modeling practices.

• Proceedings of the KSRS Conference
• /
• 2009.03a
• /
• pp.97-100
• /
• 2009

The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. An adaptive feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. In this study, the Normalized Difference Vegetation Index (NDVI) was computed for one week composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula for 1996 and 2000 using a dynamic technique, and the adaptive reconstruction of harmonic model was then applied to the NDVI time series for tracking changes on the ground surface. The results show that the adaptive approach is potentially very effective for continuously monitoring changes on near-real time.

• Journal of the Korean earth science society
• /
• v.39 no.1
• /
• pp.46-52
• /
• 2018

This paper is to study the development of three dimensional Digital Surface Model (DSM) using photogrammetry technique based on self-developed Drone (Unmanned Aerial Vehicle (UAV)). To develop DSM, we selected a study area in Jeju island and took 24 pictures from the drone. The three dimensional coordinates of the photos were made by Differential Global Positioning System (DGPS) surveying with 10 ground control points (GCP). From the calculated three dimensional coordinates, we produced orthographic image and DSM. The accuracy of DSM was calculated using three GCPs. The average accuracy of X and Y was from 8.8 to 14.7 cm, and the accuracy of Z was 0.8 to 12.4 cm. The accuracy was less than the reference accuracy of 1/1,000 digital map provided by National Geographic Information Institute (NGII). From the results, we found that the self-developed drone and the photogrammetry technique are a useful tool to make DSM and digital map of Jeju.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1925-1930
• /
• 2006

A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the wind generated current. In this paper, three dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flow over the coastal regions. The surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow and wind-generated circulation to various types of surface inhomogeneities.

• Explosives and Blasting
• /
• v.37 no.3
• /
• pp.1-12
• /
• 2019

The analysis methods of blast analysis models are classified into direct analysis and indirect analysis, and the latter is divided into semi-empirical and numerical analysis methods. In order to evaluate the applicability of the ELS blast analysis program, which is a program for analyzing the semi-empirical models, this study selected a simplified analytical model and examined the blast load characteristics of free-air burst explosion and surface burst explosion by using AT-Blast, RC-Blast, and Kinney and Graham's empirical equations, which are the semi-empirical analysis programs. As a result of analyzing the explosion pressure for the scaled distance and the incidence angle for the simplified analytical model, an appropriate analysis can be performed when the range of the scaled distance in the free-air burst explosion analysis was 0.3~0.461 and when the range of the scaled distance in the surface burst explosion analysis was 0.378~0.581. In terms of the incidence angle, the results analyzed within $45^{\circ}$ were considered to be appropriate.

• Journal of the Korean association of regional geographers
• /
• v.14 no.1
• /
• pp.19-26
• /
• 2008

A validation study has been performed using the Soil and Water Assessment Tool(SWAT) model with data collected for the Neponset River watershed, which includes roughly 130 square miles of land located southwest of Boston. All of this land drains into the Neponset River, and ultimately into Boston Harbor. This paper presents the methodology of a SWAT model. The calculated contribution of the baseflow to the streamflow is far too high whereas the interflow is strongly underestimated. Alternatively, the modified and calibrated model yields far better results for the catchment. The modification allows hydrological processes to be modeled while not restraining the applicability of the model to catchments with other characteristics. For this study, the SWAT 2005 model is used with ArcGIS 9.1 as an interlace, and sensitivity analysis is performed to provide rough estimated values before adjusting sensitive input parameters during calibration period.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.449-453
• /
• 2016

하천 구역에 존재하는 인력 및 장비의 접근이 물리적으로 불가능한 공간에 대한 지형정보 취득의 한계를 극복하기 위한 대안으로 소형 UAV(Unmanned Aerial Vehicle)의 활용성을 살펴보고자, 낙동강 달성보와 강정고령보 사이에 위치하는 습지구간에 대한 영상촬영 및 분석을 통한 지형측량을 실시하였다. 홍수터 지형측량에 있어 소형 UAV를 이용한 사진측량의 신뢰성과 정확성을 평가하기 위하여, Network RTK를 이용한 육상측량결과와 정사영상 분석결과를 비교하여 '항공레이저측량 작업규정'의 '수치표고모델 규격 및 정확도'에 제시된 기준에 의거하여 수직위치 정확도를 검토하였다. 검토 결과 과대오차를 배제할 경우 지표면 상태에 따라 1/1,000~1/5,000의 정사영상 및 수치표고모델 제작이 가능함을 확인할 수 있었다.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.1
• /
• pp.61-70
• /
• 2008

The control and prediction of surface settlement, gradient and ground displacement are the main factors in shallow tunnel design and construction in urban area. For deformation analysis of shallow tunnel due to excavation it is important to identify possible deformation mechanism of shear bands developing from tunnel shoulder to the ground surface. This paper investigaties quantitatively the deformation behavior of shallow tunneling by model tunnel test and strain softening analysis Incorporating the reduction of shear stiffness and strength parameters. The comparison of model tunnel test result and numerical simulation using strain softening analysis showed good agreement in crown settlement, normalized subsidence settlement and developing shear bands above tunnel shoulder. In this study, it is blown that the strain softening modeling is applicable to the nonlinear deformation analysis of shallow tunnel.

• Tunnel and Underground Space
• /
• v.20 no.2
• /
• pp.73-81
• /
• 2010

The paper presents the application of FE simulations of NATM tunnel using different constitutive models. The results from a series of two dimensional plane strain finite element analyses of medium-liner interaction for NATM are presented. Four types of constitutive models are considered, namely, linear elastic, elasto-plastic Mohr-Coulomb, Hardening-Soil, Soft-Soil model. The design for tunnels requires a proper estimate of surface settlement and lining forces. It is shown that the advanced constitutive model gives better predictions for both ground movement and structural forces.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.149-156
• /
• 2007

부산의 대표적 큰 계곡인 성지곡수원지는 남쪽으로 부산의 최대 도심인 서면을 향해 열려 있고, 그 이외의 삼면은 높은 산지로 둘러싸여 있다. 그래서 성지곡-서면-남항 일대는 낮에는 해풍이 곡풍(남풍)의 형태로 불고, 야간에는 산풍이 육풍(북풍)의 형태로 불고 있다. 이렇게 형성된 국지풍 순환의 규모와 특성을 평가하기 위하여, 계곡 입구와 도심인 서면 부근에 자동기상관측장치를 설치하여 특별 관측을 수행하였다. 관측결과 주간에는 서면 부근의 기온이 성지곡 입구보다 낮았고, 야간에는 이와 반대로 나타났으며 그 차이는 대체로 $3^{\circ}C$ 내외였다. 이것은 주로 지표면 가열의 의한 기단변질의 결과로 판단된다. 관측 일에 확인된 도로표면온도는 낮에 약 65도까지 상승하였으며 야간에도 30도 정도의 고온이 유지되었다. 이 연구에서는 현장관측으로 확인된 기단변질과정을 이해하기 위하여 2차원 대류모델을 이용한 수치실험을 수행하였다. 수치실험의 결과 낮에는 지표로부터 약 $150W/m^2$이상의 현열이 보급됨이 확인되었다. 야간에도 $10W/m^2$ 내외의 현열이 대기 중으로 보급되어 성지곡 수원지에서 발원된 냉기류를 가열시키고 있음이 확인되었다.