• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.1
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• pp.64-77
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• 2013

In this paper, we propose a joint bandwidth allocation and path selection scheme for IEEE 802.16j networks in uplink with cooperative relaying, and we evaluate the performance of the proposed scheme by using OPNET based simulation in hilly terrain with heavy tree density. The proposed scheme maximizes the system throughput in uplink with cooperative relaying in IEEE 802.16j networks. Then, we transform the proposed scheme into multi-dimensional multiple choice knapsack problem (MMKP) based scheme. We also propose uplink throughput maximization scheme and MMKP based scheme without cooperative relaying. We show that the system throughput of the proposed MMKP based scheme is higher than that of link quality based scheme, and cooperative relaying provides higher system throughput than the conventional case without cooperative relaying in uplink.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.637-654
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• 2023

In recent years, the number of users has been increasing with the rapid development of earth observation satellites. In response, the Committee on Earth Observation Satellites (CEOS) has been striving to provide user-friendly satellite images by introducing the concept of Analysis Ready Data (ARD) and defining its requirements as CEOS ARD for Land (CARD4L). In ARD, a mask called an Unusable Data Mask (UDM), identifying unnecessary pixels for land analysis, should be provided with a satellite image. UDMs include clouds, cloud shadows, terrain shadows, etc. Terrain shadows are generated in mountainous terrain with large terrain relief, and these areas cause errors in analysis due to their low radiation intensity. previous research on terrain shadow detection focused on detecting terrain shadow pixels to correct terrain shadows. However, this should be replaced by the terrain correction method. Therefore, there is a need to expand the purpose of terrain shadow detection. In this study, to utilize CAS500-4 for forest and agriculture analysis, we extended the scope of the terrain shadow detection to shaded areas. This paper aims to analyze the potential for terrain shadow detection to make a terrain shadow mask for South and North Korea. To detect terrain shadows, we used a Hill-shade algorithm that utilizes the position of the sun and a surface's derivatives, such as slope and aspect. Using RapidEye images with a spatial resolution of 5 meters and Sentinel-2 images with a spatial resolution of 10 meters over the Korean Peninsula, the optimal threshold for shadow determination was confirmed by comparing them with the ground truth. The optimal threshold was used to perform terrain shadow detection, and the results were analyzed. As a qualitative result, it was confirmed that the shape was similar to the ground truth as a whole. In addition, it was confirmed that most of the F1 scores were between 0.8 and 0.94 for all images tested. Based on the results of this study, it was confirmed that automatic terrain shadow detection was well performed throughout the Korean Peninsula.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.415-422
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• 2013

The contents development for the Internet and cyber tour has been attempted in a number of areas. 3D topography of the spatial environment, land planning and land information contents as a 3D tour of the future ubiquitous city safe for tourism due to the implementation of information made available major area. Domestic service, and in urban areas of the country where land and precise spatial information in order to shoot satellites and aircraft in the area you want to mount the camera on a variety of photo images taken by conducting 3D spatial that is required is able to obtain the information. Geo spatial information in a variety of direct or indirect acquisition of the initial spatial data into a database for accurate collection, storage, editing, manipulation and application technology changes in the future by establishing a database of 3D spatial by securing content organization ubiquitous tourist to take advantage of new tourism industry was greatly. As a result of this study for future tourism using geo spatial information and analysis of 3D modeling by intelligent land information indirectly, with quite a few stereo site experience and a variety of tourist spatial acquisition and utilization of information could prove.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.271-279
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• 2019

In extreme environment regions, unmanned rovers equipped with various sensors and devices are being developed for long-term exploration on behalf of humans. On the other hand, due to the harsh weather conditions and rough terrain, the rover camera has limited visible distance and field of view. Therefore, the rover cameras should be located for safe navigation and efficient terrain mapping. In this regard, to minimize the cost and time to manufacture the camera system on a rover, the simulation method using the rover design is presented to optimize the camera locations on the rover efficiently. In the simulation, a simulated terrain was taken from cameras with different locations and angles. The visible distance and overlapped extent of camera images, and terrain data accuracy calculated from the simulation were compared to determine the optimal locations of the rover's cameras. The simulated results will be used to manufacture a rover and camera system. In addition, self and system calibrations will be conducted to calculate the accurate position of the camera system on the rover.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.343-350
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• 2003

The range of applications of artificial neural networks(Am) in many branches of geotechnical engineering is growing rapidly. This study was undertaken to develop an analysis model representing ultrasonically enhanced soil flushing by the use of ANN. Input data for the model-development were obtained by laboratory study, and used for training and verification. Analyses involved various ranges of momentum, loaming rate, activation function, hidden layer, and nodes. Results of the analyses were used to obtain the optimum conditions for establishing and verifying the model. The coefficient of correlation between the measured and the predicted data using the developed model was relatively high. It shows potential application of ANN to ultrasonically enhanced soil flushing which is not easy to build up a mathematical model.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.247-247
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• 2021

국내외적으로 하도 내의 흐름을 해석하기 위해 다양한 2차원 흐름해석 모형이 적용되고 있다. 2차원 흐름해석 모형은 기존의 1차원 흐름 해석 모형에서 해석하기 어려운 확산형 홍수파 해석에 강점을 가지고 있어 도심 하천의 외수 범람 예측 등에도 사용되고 있다. 하지만 복잡한 지형 형상을 어떻게 격자로 구성하는가에 따라 해석의 효율성과 정확성이 크게 좌우된다. 초기의 2차원 흐름해석 모형은 주로 정형격자 기반의 단순한 셀을 제작하여 구동되었다. 하지만 매우 빠른 유속과 복잡한 형상을 반영하기 위해서는 전체 격자를 조밀하게 구성할 필요가 있으므로 계산 효율이 떨어지는 문제점이 있다. 그렇기 때문에 대안으로 삼각망과 혼합망 등 비정형 격자를 사용하여 필요한 구역만 격자를 조밀하게 구성하는 방법을 사용하고 있지만 이 방법 또한 추가적인 계산 과정에 따른 계산 시간의 증가가 필연적이다. 따라서 최근에는 정형격자와 비정형격자에 대하여 wet-dry front matrix 최적화, 절점제거법 등 다양한 기법을 통하여 계산 효율을 향상시키고 있는 실정이다. 따라서 본 연구에서는 HLLC Rimann solver와 2차 정확도 기법인 MUSCL-Hancock Method를 적용한 유한체적기반 천수방정식을 기반으로 다양한 격자 구성에 따른 2차원 흐름해석 모형의 효율성 분석을 수행하고, 이를 통해 최적의 흐름해석 방안을 제시하고자 한다.

• Journal of the Society of Disaster Information
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• v.14 no.2
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• pp.219-229
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• 2018

Purpose: This research proposes an optimization model for effective evacuation routing and scheduling of civilians near the border area when full-scale war threats heighten. Method: To reflect the reality, administrative unit network is created using Kruscal's Algorithm, Harmony Search, CCRP based on the geographical features, population, and traffic data of real cities, and then, optimal civilian evacuation routes are found. Results: Optimal evacuation routes and schedules are computed by repetitive experiments, and it is found that the scenario that minimizes the average civilian evacuation time is effective for the civilian evacuation plan. Conclusion: By using the civilian evacuation plan this research proposes, at the time of establishing the actual civilian evacuation plan, quantitative analysis is used for the effective plan making rather than only depending.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.427-436
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• 2015

This study aims to select an optimal site for the development of small-scaled artificial ground water recharge system with the purpose of 50ton/day pumping in dry season. First of all, the topography shape satisfying the numerous factors of a hydraulic model experiment is defined and an appropriate pumping efficiency is calculated through the model experiment of injection and pumping scenario. In next step, GIS(Geographic Information System) database are constructed by processing several geospatial data to explore the optimal site. In detail, watershed images are generated from DEM(Digital Elevation Model) with 5m cell size, which is set for the minimum area of the optimal site selection. Slope maps are made from DEM to determine the optimal hydraulic gradient to procure the proper aquifer undercurrent period. Finally, the suitable site for artificial recharge system is selected using an integration of overall data, such as an alluvial map, DEM, orthoimages, slope map, and watershed images.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.85-99
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• 2020

Reservoir is an important infrastructure of our society because it can store immense amount of water for various usages - manufacturing, agriculture, drinking, power generation, tourism etc. For maintenance of reservoir, various efforts in administrative and technological aspects are periodically conducted and monitoring the conditions of reservoir bed is the first priority for maintenance of reservoir. To check the conditions of reservoir bed, we measured depth of reservoir by using echo sounder, which is relatively reliable, prior to discharging of stored water and surveyed topography of reservoir by using UAV after discharging of water. Then, we conducted interpolation of measured depth of water by means of inverse distance weighting interpolation, Kriging interpolation, minimum curvature interpolation and radial basis function interpolation and calculated the volume of reservoir for each interpolation method. We compared the calculated volume of reservoir with the volume of water calculated by UAV after discharging of water and found the following results: First, as results of the above processes, we found that the Kriging interpolation was 97% correct in measurement of the volume of reservoir. Second, as results of comparison of differences between topographical areas and interpolated areas after selection of cross section for comparison, Kriging interpolation was found to have the most similar configuration with the topographical configuration by showing the least difference in the area of cross section. Therefore, it is determined that the optimal modeling of reservoir bed with the water depth data measured by echo sounder shall provide basic information for efficient maintenance of reservoir.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.374-376
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• 2012

우리나라 항만 입출항 통항 선박의 대형화, 고속화에 따른 해양안전사고가 증가하고 있어 항만 연안 해역에서의 해상교통 안전 확보가 절실히 요구되고 있는 실정으로, 최근 국제항로표지협회(IALA)에서 항로표지 설계와 배치계획에 대한 의사결정을 지원할 수 있는 항로표지 전문 기능 시뮬레이터의 개발과 주요 항로의 항로표지 설계 및 계획 등을 검증할 수 있는 시스템 필요성을 제기하였다. 우리나라 주요 항로의 항로표지 설계와 적정 배치 여부 등을 검증하고 보완할 수 있는 시뮬레이션 시스템이 필요하며 3차원 가상현실 기법을 이용하여 항로표지의 신설 및 이설에 따른 여러 가지 효과를 직관적으로 파악하고 대상 해역의 특성이 고려된 다양한 해상교통환경 변화에 따른 항로표지의 신설 및 이설 효과를 선박 운항자 관점에서 검증하거나, 새로운 항만 항로 건설시 최적 항로표지 배치에 대한 의사결정을 지원하기 위한 항로표지용 시뮬레이터 시스템 개발이 진행되고 있다. 이러한 항로표지 시뮬레이터 개발에 필요한 항로표지 관련 속성에 대하여 기술하였다.