• 한국건축시공학회지
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• 제20권2호
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• pp.199-212
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• 2020

In evaluating the competitiveness of construction companies and their development strategies, patents are a useful and objective source of technical information. In this study, the cutting-edge technologies of construction industries of China, Japan, and South Korea were investigated based on the data of patent applications filed by a total of 15 construction companies (five companies from each country). The related technologies were classified into six core technology groups based on their keywords. After that, we used four patent analysis methods: time series analysis, IP (Intellectual Property) emergence level analysis, spiral module analysis, and OS (Object-Solution) Matrix analysis, to identify the promising technologies/vacant technologies for global construction companies in China, Japan, and South Korea, and to analyze the technical competitiveness of the three countries. The findings of this study showed that each country can claim a relative technological advantage over the others. Overall, 3D printing and offsite construction technology, data acquisition technology, AR and VR technology are expected to be promising in the Asian region. The present study contributes to the body of knowledge by expanding our understanding of technological innovation for the competitiveness of companies and the technology development strategies pursued by the construction industries of China, Japan, and South Korea.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제9권5호
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• pp.578-587
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• 2003

DSTM (Dual Stack Transition Mechanism)은 현재 주목받고 있는 IPv4/IPv6 연동기술로 서 터널링 방식을 적용한 기술중의 하나이다. DSTM은 fevers (IPv4-over-lPv6) 터널링과 임시 글로벌 IPv4 주소의 할당방식을 적용하여 IPv4와 IPv6간의 연결성을 지원한다. TEP (Tunnel End Point)는 DSTM 도메인과 인터넷망의 경계 라우터로서 4over6 터널링 패킷의 캡슐화와 복원기능을 적용하여 양방향 통신을 제공한다. 본 논문에서는 기본적인 IPv6 프로토콜 표준안의 내용을 기술하였으며 DSTM에서의 요구사항을 만족하는 TEP 데몬 프로그램을 설계하고 구현하였다. TEP 데몬은 DSTM 노드로부터 전송되는 4over6 패킷을 분석하여 동적으로 4over6 터널링 인터페이스를 구성하여 DSTM 노드와 IPv4-only 노드간에 통신을 가능하게 한다. 최종적으로 구현된 TEP를 적용한 시험망을 구성하고 성능을 측정하여 결과를 제시하였다. 이러한 결과를 통하여 구현된 TEP 데몬이 DSTM 서비스에 적합한 성능을 제공 할 수 있음을 확인하였다.

• 한국산학기술학회논문지
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• 제21권3호
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• pp.51-56
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• 2020

본 논문은 2008년 금융위기의 시기에 파산을 겪고 타 완성차 업체에 비해 늦게 자율주행차 개발에 합류한 General Motors (GM)가 기술 및 실행력에 있어 앞서 나간 원인을 파악하기 위하여 기술개발 전략과 정책적 지원 요인을 분석하였다. 연구결과 다음과 같은 성공원인을 파악할 수 있었다. 첫째, GM은 상대적으로 짧은 기간 내 기술개발 성과를 달성하기 위하여 수익성이 낮은 해외사업의 축소와 더불어 자율주행차 관련부문에 집중 투자하고 공격적 M&A를 통해 상대적으로 미비한 기술을 보완할 수 있는 기업을 인수하였다. 둘째, 자율주행차 개발과 생산을 위한 기술뿐아니라, 부품, 솔루션, 서비스 및 판매에 이르기까지 수직적 계열화를 추진하여 실행력을 강화하였다. 셋째, 커넥티드카 프로젝트, M-City 및 NCHRP 프로그램과 같이 직접적 협업을 유도한 안정적인 제도와 정책적 지원이 신속한 기술개발의 배경이 되었다. 본 연구는 선진국에 비해 상대적으로 기술개발이 늦은 국내기업들의 향후 기술개발 전략 제고를 위한 실무적 시사점 및 제도 수립과 지원 측면에서의 정책적 시사점을 제시하고 있다.

• 대한공간정보학회지
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• 제19권4호
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• pp.47-53
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• 2011

최근 들어 범세계적으로 기상이변과 지구온난화에 따른 환경 및 생태계의 변화로 자연적, 인위적 재난이 증가하고 있는 가운데 우리가 살고 있는 한반도 주변 또한 자연재해로 인한 인명 및 재산의 피해가 점차 증가하고 있다. 반복적인 재난으로부터 인명과 재산을 보호하기 위해 과학적인 분석과 체계적인 재해관리가 필요한 시점이다. 이에 본 연구에서는 과학적인 방재 대책의 일환으로 수치영상, 수치지형도 및 재해정보를 활용함으로써 이해하기 어려운 기존 방재지도의 도식적 표현에 따른 한계를 극복하여 누구나 시각적으로 쉽게 인지할 수 있는 수치영상기반의 방재지도를 제작하고, 제작된 방재지도를 통해 방재정보시스템을 개발하였다. 방재지도와 방재정보시스템은 재해 피해현황 및 상황의 가독성을 높여 효과적인 대민서비스가 가능하며, 신속한 의사결정을 지원함으로써 보다 효율적인 자연재해 상황분석 및 대응에 활용이 가능할 것이다.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.437-444
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• 2015

Satellite selection and exclusion techniques have been applied to the global navigation satellite system (GNSS) with the aim of achieving a balance between navigational performance and computational efficiency. Conventional approaches to satellite selection based on the best dilution of precision (DOP) are excessively computational and complicated. This paper proposes a new method that applies a geometric sensitivity index of individual GNSS satellites. The sensitivity index is derived using the inner product of the line of sight (LOS) vector of each satellite. First, the LOS vector is computed, which accounts for the geometry between the satellite and user positions. Second, the inner product of each pair of LOS vectors is calculated, which indicates the proximities of the satellites to one another. The proximity can be determined according to the sensitivity of each satellite. A post-processing test was conducted to verify the reliability of the proposed method. The proposed index and the results of a conventional approach that measures the dilution of precision (DOP) were compared. The test results demonstrate that the proposed index produces results that are within 96% of those of the conventional approach and reduces the computational burden. This index can be utilized to estimate the sensitivity of individual satellites, obtaining a navigation solution. Therefore, the proposed index applies to satellite selection and exclusion as well as to the sensitivity analyses of multiple GNSS applications.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.382-385
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• 2007

Constantly enhancing positioning accuracy by the Global Positioning System (GPS) technique is of great importance, but challenging, especially after the GPS positioning technique has been improved considerably during the past two decades. The associated main error sources have been reduced substantially, if not eliminated. Troposhpeic influence with its highly temporal and spatial variability appears to be one of the major error sources. It is hence an increased interest among GPS researchers to reduce the tropospheric influence or delay. Two techniques have been commonly implemented to correct the tropospheric impact. The first technique, known as parameter estimation, characterizes the path delay with empirical models and the parameters of interest are determined from the GPS measurements. The second strategy, termed as external correction, involves independent path delay measurements. The present study is an integration of both techniques in which the parameter estimation as well as external correction are used to correct the path delay for $110{\sim}210$ km range baselines. Twenty-four parameters have been obtained in 24 hours solution by setting the cutoff angle at 3 and 15 degrees for parameter estimation strategy. Measurements from meteorological instruments and water vapor radiometer (WVR) are applied in the GPS data processing, separately, as an external strategy of present research work. Interesting results have been found, indicating more stable repeatability in baseline when the external correction strategy is applied especially with the inclusion of WVR observations. The offset of an order of 1 cm is found in the baselines determined by the two strategies. On the other hand, parameter estimation exhibits more stable in terms of GPS height repeatability. The offset in the GPS height determined by the two strategies is on the order of few centimeters.

• 한국측량학회지
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• 제16권1호
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• pp.17-26
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• 1998

본 논문은 Fast Hartley Transform 기법을 소개하고 이를 이용하여 한반도 주변의 지오이드를 결정하기 위한 것이다. 본 연구에서 사용한 중력 측정 데이터는 69,001점으로 남한지역과 BGI로부터 획득한 해상중력데이터로 구성하였으며, 북한쪽은 회기분석에 의하여 $1km\times{1km}$ 격자 간격으로 추정하였다. 지오이드의 결정을 위하여 96년에 발표된 EGM96 포텐셜모델을 채택하여 차수 360까지 계산하여 장 파장효과를 구하였고, FHT기법을 적용하여 중력데이터로부터 중 파장효과를 계산하여 이들 두 효과를 합하여 최종 지오이드면을 결정하였다. 본 연구를 통하여 얻어진 지오이드고를 GPS/Leveling에 의하여 구한 지오이드고와 비교한 결과 표준편차가 약 33 cm 이었다.

• 한국측량학회지
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• 제25권6_1호
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• pp.545-555
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• 2007

3D buildings are the most prominent feature comprising urban scene. A few of mega-cities in the globe are virtually reconstructed in photo-realistic 3D models, which becomes accessible by the public through the state-of-the-art online mapping services. A lot of research efforts have been made to develop automatic reconstruction technique of large-scale 3D building models from remotely sensed data. However, existing methods still produce irregular building polygons due to errors induced partly by uncalibrated sensor system, scene complexity and partly inappropriate sensor resolution to observed object scales. Thus, a geometric regularization technique is urgently required to rectify such irregular building polygons that are quickly captured from low sensory data. This paper aims to develop a new method for regularizing noise building outlines extracted from airborne LiDAR data, and to evaluate its performance in comparison with existing methods. These include Douglas-Peucker's polyline simplication, total least-squared adjustment, model hypothesis-verification, and rule-based rectification. Based on Minimum Description Length (MDL) principal, a new objective function, Geometric Minimum Description Length (GMDL), to regularize geometric noises is introduced to enhance the repetition of identical line directionality, regular angle transition and to minimize the number of vertices used. After generating hypothetical regularized models, a global optimum of the geometric regularity is achieved by verifying the entire solution space. A comparative evaluation of the proposed geometric regulator is conducted using both simulated and real building vectors with various levels of noise. The results show that the GMDL outperforms the selected existing algorithms at the most of noise levels.

• 대한원격탐사학회지
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• 제27권3호
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• pp.303-314
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• 2011

Surface albedo is an important parameter of the surface energy budget, and its accurate quantification is of major interest to the global climate modeling community. Therefore, in this paper, we consider the direct solution of kernel based bidirectional reflectance distribution function (BRDF) models for retrieval of normalized reflectance of high resolution satellite. The BRD effects can be seen in satellite data having a wide swath such as SPOT/VGT (VEGETATION) have sufficient angular sampling, but high resolution satellites are impossible to obtain sufficient angular sampling over a pixel during short period because of their narrow swath scanning when applying semi-empirical model. This gives a difficulty to run BRDF model inferring the reflectance normalization of high resolution satellites. The principal purpose of the study is to estimate normalized reflectance of high resolution satellite (RapidEye) through BRDF components from SPOT/VGT. We use semi-empirical BRDF model to estimated BRDF components from SPOT/VGT and reflectance normalization of RapidEye. This study used SPOT/VGT satellite data acquired in the S1 (daily) data, and within this study is the multispectral sensor RapidEye. Isotropic value such as the normalized reflectance was closely related to the BRDF parameters and the kernels. Also, we show scatter plot of the SPOT/VGT and RapidEye isotropic value relationship. The linear relationship between the two linear regression analysis is performed by using the parameters of SPOTNGT like as isotropic value, geometric value and volumetric scattering value, and the kernel values of RapidEye like as geometric and volumetric scattering kernel Because BRDF parameters are difficult to directly calculate from high resolution satellites, we use to BRDF parameter of SPOT/VGT. Also, we make a decision of weighting for geometric value, volumetric scattering value and error through regression models. As a result, the weighting through linear regression analysis produced good agreement. For all sites, the SPOT/VGT isotropic and RapidEye isotropic values had the high correlation (RMSE, bias), and generally are very consistent.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권6호
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• pp.66-78
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• 2011

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is increasing due to global warming and climate change. Artificial recharge schemes such as well recharge of surface water and roof-top rainwater harvesting can be a useful method to manage water resources in Korea. In this study, potential artificial recharge site is evaluated using geographic information system with hydrogeological and social factors. The hydrogeological factors include annual precipitation, geological classification based on geological map, specific capacity and depth to water level of national groundwater monitoring wells. These factors were selected to evaluate potential artificial recharge site because annual precipitation is closely related to source water availability for artificial recharge, geological features and specific capacity are related to injection capacity and depth to water is related to storage capacity of the subsurface medium. In addition to those hydrogeological factors, social aspect was taken into consideration by selecting the areas that is not serviced by national water works and have been suffered from drought. These factors are graded into five rates and integrated together in the GIS system resulting in spatial distribution of artificial recharge potential. Cheongsong, Yeongdeok in Gyeongsangbuk-do and Hadong in Gyeongsangnam-do, and Suncheon in Jeollanam-do were proven as favorable areas for applying artificial recharge schemes. Although the potential map for artificial recharge in South Korea developed in this study need to be improved by using other scientific factors such as evaporation and topographical features, and other social factors such as water-curtain cultivation area, hot spring resorts and industrial area where groundwater level is severely lowered, it can be used in a rough site-selection, preliminary and/or feasibility study for artificial recharge.