• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1143-1155
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• 1999

셀룰러 방식의 이동통신 시스템에서 전파의 유효신호 도달범위를 예측하기 위해서는 전파전파 모델을 이용한 예측기법이 주로 사용된다. 그러나, 전파과정에서 주변 지형지물에 의해 발생하는 전파손실은 매우 복잡한 비선형적인 특성을 가지며 수식으로는 정확한 표현이 불가능하다. 본 논문에서는 신경회로망의 함수 근사화 능력을 이용하여 전파손실 예측모델을 생성하는 방법을 제안한다. 즉, 전파손실을 송수신 안테나간의 거리, 송신안테나의 특성, 장애물 투과영향, 회절특성, 도로, 수면에 의한 영향 등과 같은 전파환경 변수들의 함수로 가정하고, 신경회로망 학습을 통하여 함수를 근사화한다. 전파환경 변수들이 신경회로망 입력으로 사용되기 위해서는 3차원 지형도와 벡터지도를 이용하여 전파의 반사, 회절, 산란 등의 물리적인 특성이 고려된 특징 추출을 통해 정량적인 수치들을 계산한다. 이와 같이 얻어진 훈련데이타를 이용한 신경회로망 학습을 통해 전파손실 모델을 완성한다. 이 모델을 이용하여 서울 도심 지역의 실제 서비스 환경에 대한 타 모델과의 비교실험결과를 통해 제안하는 모델의 우수성을 보인다.Abstract In cellular mobile communication systems, wave propagation models are used in most cases to predict cell coverage. The amount of propagation loss induced by the obstacles in the propagation path, however, is a highly non-linear function, which cannot be easily represented mathematically. In this paper, we introduce the method of producing propagation loss prediction models by function approximation using neural networks. In this method, we assume the propagation loss is a function of the relevant parameters such as the distance from the base station antenna, the specification of the transmitter antenna, obstacle profile, diffraction effect, road, and water effect. The values of these parameters are produced from the field measurement data, 3D digital terrain maps, and vector maps as its inputs by a feature extraction process, which takes into account the physical characteristics of electromagnetic waves such as reflection, diffraction and scattering. The values produced are used as the input to the neural network, which are then trained to become the propagation loss prediction model. In the experimental study, we obtain a considerable amount of improvement over COST-231 model in the prediction accuracy using this model.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.163-171
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• 1992

The narrow interal grid is effective in accuracy, but it is not able to make a densely grided sample, so that smoothing is requared. In digital elevation models, an application of the finite elements method is effective to smooth the undesired noise which is generated in aquisition of elevation data. And this is one of the simple and direct method to solve the problem for discontinuity of terrain. Therefore, the finite elements method is applied to study. In digital elevation model by appling the finite element, smoothing is affected by the height weight. In this study, the relation equation between elevation weight and standard deviation of smoothing was obstained as Y = 1900625 $X^4-312987.6$ $X^3+20330.72$ $X^2-578.6029$ X+12.63772 and from this function, Optimum elevation weight is 0.05.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.615-629
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• 2014

This study analyzed existing patents related to real-time monitoring and detection technology for landslides on natural terrain. The purpose of patent analysis is to understand landslide hazard technology trends and to develop new advanced technology. This study searched patent data using key words related to landslide monitoring and detection in Korea, the USA, Japan, China (Hong Kong), Europe, and Taiwan. The patents were divided into five main categories and five to seven subcategories in each main category and analyzed by year, country, and applicants. The results were utilized to derive a portfolio of promising technologies for each country. The analysis results will also contribute to the development of more effective research strategies and to categorize research findings from previous studies on landslide hazards.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.511-523
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• 2014

Limit equilibrium analysis and finite difference analysis were used to evaluate slope stability in the in Gohan, Korea, which is affected by large-scale tensile cracks and uplift. There is a thick colluvial layer in the study area and predicting ground behavior is problematic because the presence of clay makes it difficult to determine the strength parameters of the soil. Consequently, a numerical model able to reflect the collapse properties of the site was required that applied the modified boundary layer model and calculated the strength parameters using back analysis. The numerical simulation results that consider the strength parameter one does with the present situation the establishment of the pile is completed, and the simulation is able to asses ground stability in complex terrain in a reliable manner. Also the somewhat it judges with the fact that it will be able to provide the fundamental data which secures the stability of the segment where it is unstable.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.553-559
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• 2011

The bicycle use activation plan reduces a greenhouse gas exhaust, and economic convenience, movement timely shortening, health effect will be able to expect but the bicycle user is few. The nationwide bicycle road projects is advanced by the countermeasure for a bicycle use activation. It is advanced a bicycle road basic plan even from each local government. The research against a route selection is advanced actively. But the research against a data process is not coming out the accurate research method. It follows a financial one bicycle road design standard from ministry of land, Transport and maritime affairs. But vertical grade in bicycle road design standard is exception becoming that about unavoidable case with geomorphic environments. From the research which it sees the existing bicycle road consider should have to make the terrain situation of yeosu, slope standard connection about under considering it presented the bicycle road route selection which is possible. It included a lane and road width with additional element and establishment in the bicycle road was produced suitable bicycle road route. The area where the mountain district is many when selecting bicycle road, will be used with application plan of slope standard.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.153-158
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• 1998

Since the mid-1990′s, researches on 3D GIS have been regarded as one of main issues both in the academic sites and commercial vendors; recently, some prototyped systems or the first versioned software systems of commercial basis are being reported and released. Unlike conventional 2D GIS, which consists in intelligent structured GIS or desktop GIS, every 3D GIS has its own distinguished features according to data structure-supporting capability, GIS-styled functionality, external database accessibility, interfacing extents with 2D GIS, 3D visualization/texture mapping ability, and so forth. In this study, technical aspects related to system development, SERI-Web3D GIS ver. 1.2, are explained. Main features in this revised 3D GIS can be summarized: 2-tier system model(client-server), VGFF(Virtual GIS File Format), internal GIS import, Feature manager(zoning, layering, visualization evironment), Scene manager(manage 3D geographic world), Scene editor, Spatial analyzer(Intersect, Buffering, Network analysis), VRML exporter. While, most other 3D GISes or cartographic mapping systems may be categorized into 3D visualization systems handling terrain height-field processing, 2D GIS extension modules, or 3D geometric feature generation system using orthophoto image: actually, these are eventually considered as several parts of "real 3D GIS". As well as these things, other components, especially web-based 3D GIS, are being implemented in this study: Surface/feature integration, Java/VRML linkage, Mesh/Grid problem, LOD(Level of Detail)/Tiling, Public access security problem, 3-tier architecture extension, Surface handling strategy for VRML.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.4
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• pp.305-315
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• 2020

The purpose of this study is to compare algorithms of single photo resection, which determines the exterior orientation parameters used in fields such as photogrammetry, computer vision, robotics, etc. To this end, the algorithms were compared by generating experimental data by simulating terrain based on a camera used in aerial and close-range photogrammetry. Through experiments on aerial photographic camera that was taken almost vertically, it was possible to determine the exterior orientation parameters using three ground control points, but the Procrustes algorithm was sensitive to the configuration of the ground control points. Even in experiments with a close-range amateur camera where the attitude angles of the camera change significantly, the algorithm was sensitive to the configuration of the ground control points, and the other algorithms required at least six ground control points. Through experiments with two types of cameras, it was found that cosine lawbased spatial resection shows performance similar to that of a traditional photogrammetry algorithm because the number of iterations is short and no explicit initial values are required.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.303-309
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• 2008

A probability of slope hazards was predicted at a natural terrain around the stone relics of Jinjeon-saji area, which is located in Yangyang, Kangwon Province. As the analyzing results of field investigation, laboratory test and geology and geomorphology data, the effect factors of landslides occurrence were evaluated. Also, the landslides prediction map was made up using the prediction model by the effect factors. The landslide susceptibility of stone relics was investigated as the grading classification of occurrence probability. In the landslides prediction map, the high probability area was $3,489m^2$ and it was 10.1% of total prediction area. The high probability area has over 70% of occurrence probability. If landslides are occurred at the predicted area, the three stories stone pagoda of Jinjeon-saji(National treasure No. 122) and the stone lantern of Jinjeon-saji(Treasure No.439) will be collapsed by debris flow.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.21-32
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• 2016

Open-pit mines are the critical infrastructure for acquiring natural resources. Since it could be endangered by environmental and safety problems during operations, continuous monitoring is required for this type of mine. However, the domestic level management and accumulation of present state data of the topographical alteration are incurred by the development and restoration of open-pit mines relying on digital topographic maps and site surveys. Because of it, other than an expert cannot be viewed easily examines those changes information of open-pit mines in the domestic level. If the efficient management and public access of the open-pit mine is targeted, it is easy to build a web-based three-dimensional monitoring system, utilized in the space information software of open source. Therefore, we purposed on developing an open-pit mine monitoring system to support the development and restoration of the ecology-friendly environment, which could be easily monitored by the general public for those changes within terrain and environments due to operations of the mine.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.4
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• pp.119-125
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• 2013

Since year 2001 to the present time, the aircraft accidents and serious incidents in our country have surpassed 150 occurrences. The Boeing has published the statistical summary of commercial jet airplane accidents annually for the past 10 years on the basis of the occurrence categories defined by the CICTT(CAST/ICAO Common Taxonomy Team), and the number of occurrences is in order of loss of control(LOC-I), controlled flight into terrain(CFIT) and runway excursion (RE). Like the NTSB and the EASA, when fatal and non-fatal accidents are aggregated, though fatality rate is low, abnormal runway contact(ARC), system/component failure(SCF-PP/NP), ground handling(RAMP) rank high in the CICTT occurrence categories. With the less occurrence frequency, it is difficult to statistically analyze the aircraft accidents in our country, thus customarily the accidents and the serious incidents on aggregate are consolidated, and the statistical analysis is performed. This study categorizes the accidents and serious incidents to the domestic transportation aircraft in the past 10 years according to the CICTT occurrence categories, that is compared with foreign practices, and the implications have been discussed. From years 2001 through 2010, the accidents to the domestic transportation aircraft occurred in order of system failure(SCF-NP), ARC and power plant failure(SCF-PP), and when the accidents and the serious incidents are consolidated and analyzed, it is verified that a distribution appears similar to the European accident occurrence categories defined from 300 accident occurrence data.