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        검색결과 144

        21.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is very crucial activities that Korean army have to detect and recognize enemy’s locations and types of weapon of their artillery firstly for effective operation of friendly force’s artillery weapons during wartime. For these activities, one of the most critical artillery weapon systems is the anti-artillery radar (hereafter; radars) for immediate counter-fire operations against the target. So, in early wartime these radar’s roles are very important for minimizing friendly force’s damage because arbiters have to recognize a several enemy’s artillery positions quickly and then to take an action right away. Up to date, Republic of Korea Army for tactical artillery operations only depends on individual commander’s intuition and capability. Therefore, we propose these radars allocation model based on integer programming that combines ArcGIS (Geographic Information System) analysis data and each radar’s performances which include allowable specific ranges of altitude, azimuth (FOV; field of view) and distances for target detection, and weapons types i.e., rocket, mortars and cannon ammo etc. And we demonstrate the effectiveness of their allocation’s solution of available various types of radar asset through several experimental scenarios. The proposed model can be ensured the optimal detection coverage, the enhancement of artillery radar’s operations and assisting a quick decision for commander finally.
        4,000원
        22.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 위성의 밝기온도를 기반으로 한 정량적 강우량 추정기법의 개선을 위함이다. 우리나라 여름철 강우사례를 이용하여 강우추정을 위한 비선형 관계식을 개선하였다. 분석을 위해 레이더 자료로 기상청 기상레이더 관측망의 고도 1.5 km와 CMAX 반사도 합성자료를 사용하였으며, 위성자료는 천리안 위성의 가시, 적외, 수증기 채널의 자료를 이용하였다. 새롭게 도출된 알고리즘은 A-E method, CRR v4.0 analytic function의 결과와 비교를 하였다. 검증을 위해 우리나라 ASOS에서 관측한 지상강우량 자료를 사용하였다. 공간검증을 위해 검증지수로 POD, FAR, CSI를 계산하였으며 각각 0.67, 0.76, 0.21로 나타났다. 정량적 강우검증을 위해 MAE와 RMSE를 계산하였으며 각각 2.49, 6.18 mm/h였다. A-E에 비하여 정량적인 오차가 줄어들었으며 CRR에 비하여 공간적인 정확도가 증가하였다. 개선한 관계식을 적용한 방법이 두 알고리즘의 부족한 부분을 보완할 수 있는 것으로 판단된다. 개선한 관계식을 통해 강우를 추정하는 방법은 복잡한 알고리즘을 거치지 않고 짧은 시간에 강우추정이 가능함으로써 현업용 실시간 초단기 예보에 활용될 수 있다.
        4,000원
        24.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 기상청의 기상레이더 관측망을 이용한 하이브리드 고도면 강우추정 기법 기반의 새로운 정량적 합성강수량 추정 방법을 제시한다. HSR기법은 지형클러터, 빔차폐, 비 기상 에코 및 밝은 띠의 영향을 받지 않는 하이브리드 고도면의 반사도를 합성하는 것이 특징이다. HSR 합성반사도는 정적 HSR (STATIC)과 단일편파레이더에 대한 퍼지로직 기법과 이중편파레이더에 대한 시선방향 질감 기반의 품질관리 절차를 사용하는 동적 HSR (DYNAMIC) 합성으로 구분된다. STATIC과 DYNAMIC은 2014년 5월부터 10월까지 10개의 강우 사례에 대해 기상청 현업용 합성강우 (MOSAIC)와 비교검증 하였다. 차폐 영역에서 STATIC, DYNAMIC, MOSAIC의 상관계수는 각각 0.52, 0.78, 0.69이며 평균 상대 오차는 각각 34.08, 30.08, 40.71%로 분석되었다.
        4,800원
        25.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In 1970, Masahiro Mori proposed the uncanny valley concept. At the time, the proposal aroused little reaction, However, the uncanny valley is just a hypothesis, not a strict theory. Many subsequent studies have shown that it is true that the uncanny valley is reasonable; With the development of game consoles and personal computers, uncanny valley in video games will become more and more common. but, for the time being, special introductions and game related research on the uncanny valley are still very rare. In this paper, with Masahiro Mori’s uncanny valley as a benchmark and using the evolution of Tomb Raider’s Lara Croft over 20 years as an example, we analyze the significance of the uncanny valley in the design of realistic adventure game characters from such aspects as facial expression and texture. It's not easy to see the development of the technology in the game by using this approach. And it makes game makers determinate the scope of uncanny valley more exactly to made better games.
        4,000원
        26.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        함정에 있어서 레이더반사면적은 함정의 생존성과 직결되는 요소로써, 이에 대한 감소설계가 필요하다. 함정의 RCS에 영향을 주는 요소로써, 상부구조물, 함포, 레이더 등이 있다. 레이더의 경우 그 형상이 복잡하여 RCS 감소설계가 어려운 실정이다. 본 논문에서는 레이더의 RCS를 줄이기 위한 최신 기법 중의 하나인 폐위형 마스트에 대해 살펴보고 폐위형 마스트에 적용되는 주파수 선택 표면 (Frequency Selected Surface: FSS)의 특성을 파악하였다. FSS의 형상에 따른 가용 가능한 주파수에 대해 일반적인 레이더와 폐위형 마스트의 RCS 비교를 통해 폐위형 마스트의 RCS 감소 성능을 확인하였고, 해석 고각별, 구조물의 경사별 RCS 해석을 통해 특성을 파악하였다. 일반 적인 레이더의 경우 복잡한 형상으로 인하여 높은 RCS 값을 갖는 반면 폐위형 마스트의 경우 단순한 형상으로 인해 낮은 RCS 값을 갖는 것을 확인하였다.
        4,000원
        27.
        2017.10 구독 인증기관·개인회원 무료
        최근 도심지의 돌발적인 도로함몰로 인명해가 발생하고, 시민들에게 불안감을 야기하는 사례가 빈번히 발생하여 사회적 이슈로 부각되고 있다. 이에, 2015년 세종대학교 산학협력단을 주관으로 국토교통부, 국토교통과학진흥원이 지원하는「도로함몰 위험도 평가 및 분석기술 개발」에 대한 연구가 시작되었다. 본 연구는 장기적이고 근본적으로 도로함몰을 예방하기 위한 도로함몰 위험도 탐지시스템 및 분석 프로그램 개발, 도로함몰 위험도 평가기술 개발, 재난 예방형 도로관리 시스템 구축을 목표로 현재 3차년도 연구가 진행 중이다. 현재, 지표투과레이더와 노면영상 수집장치가 포함된 도로함몰 복합탐지 시스템을 구축하여 운용 중에 있으며 (그림 1), 해당 장비로부터 수집된 데이터를 이용하여 도로 지하시설물 및 동공탐사를 할 수 있도록 분석 자동화 알고리즘을 개발하고, 현장적용을 위한 GUI를 구축하여 그 성능을 검증하였다.
        29.
        2017.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have studied the efficient operation of the radar and the appropriateness of the installation location, when constructing the VTS system. As the Civil-Military Complex Harbour (Kangjeong Port) is completed in 2016, we set the control area within 10 nautical miles centering on Kangjeong Port, and found out and removed the operational radar blind area of VTS system to provide safe navigation information for vessels that navigating this area. Assuming that two international cruise ships entering at the same time, we performed the radar simulation and compared the images by considering the three sites of Kangjeong Port, Miaksan and Seoguipo Port. Simulation results for a single radar installed at Kangjung Port indicate that the blind area was largely affected by two large cruise ships and the surrounding islands. The blind area due to Kogunsan was considerably large when installed in Miaksan, but the blind area due to the influences of Beomseom, Moonseom and Seopseom was negligibly large. It seems that additional radar installation is necessary as a complementary solution to solve this blind area. When two radars were installed at Miaksan and Kangjeong Port, the residual blind area due to the Seopseom was 0.25 km2 at 0.1~0.33 nautical miles in the southeast direction from Seopseom. In addition, the remaining blind area with two cruise ships mutually influenced was 0.18 km2, which did not occur with a single cruise ship.
        4,000원
        32.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        OBJECTIVES: The objective of this study is to detect road cavities using multi-channel 3D ground penetrating radar (GPR) tests owned by the Seoul Metropolitan Government. METHODS: Ground-penetrating radar tests were conducted on 204 road-cavity test sections, and the GPR signal patterns were analyzed to classify signal shape, amplitude, and phase change. RESULTS : The shapes of the GPR signals of road-cavity sections were circular or ellipsoidal in the plane image of the 3D GPR results. However, in the longitudinal or transverse direction, the signals showed mostly unsymmetrical (or symmetrical in some cases) parabolic shapes. The amplitude of the GPR signals reflected from road cavities was stronger than that from other media. No particular pattern of the amplitude was found because of nonuniform medium and utilities nearby. In many cases where road cavities extended to the bottom of the asphalt concrete layer, the signal phase was reversed. However, no reversed signal was found in subbase, subgrade, or deeper locations. CONCLUSIONS: For detecting road cavities, the results of the GPR signal-pattern analysis can be applied. In general, GPR signals on road cavity-sections had unsymmetrical hyperbolic shape, relatively stronger amplitude, and reversed phase. Owing to the uncertainties of underground materials, utilities, and road cavities, GPR signal interpretation was difficult. To perform quantitative analysis for road cavity detection, additional GPR tests and signal pattern analysis need to be conducted.
        4,000원
        33.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        예비 항해사는 타선과의 충돌 가능성을 사전에 파악하여 회피할 수 있는 능력을 ARPA/레이더 시뮬레이션 교육을 통해 갖추어야 한다. 이러한 시뮬레이션 교육은 국내외 지침(해양수산부 고시, STCW 협약 등)에 교육 내용과 기간만이 명시되어 있는 것으로 조사되었다. 또한 시뮬레이션 교육 훈련 모듈의 부재로 각 해기 교육 기관에서는 자체적으로 모듈을 구성하여 관련 증서를 발행하고 있는 것으로 확인되었다. 이로 인하여 ARPA/레이더 시뮬레이션을 통한 동일한 해기 능력 함양이 어려운 것이 현실이다. 따라서 본 연구에서는 우리나라 해기 교육 기관별 동일한 능력 함양을 위하여 ARPA/레이더 시뮬레이션 교육 모듈을 표준화하고, 표준화된 모듈을 통한 교육 향상도에 대하여 검증하고자 한다. 이를 위해서 우리나라 해기 교육 기관의 시뮬레이션 교육 형태를 조사하고, 교통 조사를 기반으로 한 실해역의 교통 흐름을 반영한 시나리오 제시, 교육 훈련 및 평가를 효율적으로 하기 위한 해기사 핵심 역량 기반 모듈을 제시하였다. 그리고 2년간에 데이터를 이용하여 표준화된 모듈을 통한 교육 훈련의 향상 정도를 파악하였다. 이러한 표준화된 ARPA/레이더 시뮬레이션 모듈을 통해 각 교육 기관에서는 효율적이고 체계적인 해기 교육이 가능하고 해기능력 향상을 통한 선박 통항 안전에 기여할 수 있는 기반을 마련할 수 있다.
        4,000원
        34.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The density in uninterrupted traffic flow facilities plays an important role in representing the current status of traffic flow. For example, the density is used for the primary measures of effectiveness in the capacity analysis for freeway facilities. Therefore, the estimation of density has been a long and tough task for traffic engineers for a long time. This study was initiated to evaluate the performance of density values that were estimated using VDS data and two traditional methods, including a method using traffic flow theory and another method using occupancy by comparing the density values estimated using vehicular trajectory data generated from a radar detector. METHODS: In this study, a radar detector which can generate very accurate vehicular trajectory within the range of 250 m on the Joongbu expressway near to Dongseoul tollgate, where two VDS were already installed. The first task was to estimate densities using different data and methods. Thus, the density values were estimated using two traditional methods and the VDS data on the Joongbu expressway. The density values were compared with those estimated using the vehicular trajectory data in order to evaluate the quality of density estimation. Then, the relationship between the space mean speed and density were drawn using two sets of densities and speeds based on the VDS data and one set of those using the radar detector data. CONCLUSIONS: As a result, the three sets of density showed minor differences when the density values were under 20 vehicles per km per lane. However, as the density values become greater than 20 vehicles per km per lane, the three methods showed a significant difference among on another. The density using the vehicular trajectory data showed the lowest values in general. Based on the in-depth study, it was found out that the space mean speed plays a critical role in the calculation of density. The speed estimated from the VDS data was higher than that from the radar detector. In order to validate the difference in the speed data, the traffic flow models using the relationships between the space mean speed and the density were carefully examined in this study. Conclusively, the traffic flow models generated using the radar data seems to be more realistic.
        4,000원
        35.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES: The objective of this study was to determine the relationship between the dielectric characteristics of asphalt mixtures and the air voids present in them using ground penetrating radar (GPR) testing. METHODS : To measure the dielectric properties of the asphalt mixtures, the reflection coefficient method and the approach based on the actual thickness of the asphalt layer were used. An air-couple-type GPR antenna with a center frequency of 1 GHz was used to measure the time for reflection from the asphalt/base layer interface. A piece of aluminum foil was placed at the interface to be able to determine the reflection time of the GPR signal with accuracy. An asphalt pavement testbed was constructed, and asphalt mixtures with different compaction numbers were tested. After the GPR tests, the asphalt samples were cored and their thicknesses and number of air voids were measured in the laboratory. RESULTS: It was found the dielectric constant of asphalt mixtures tends to decrease with an increase in the number of air voids. The dielectric constant values estimated from the reflection coefficient method exhibited a slight correlation to the number of air voids. However, the dielectric constant values measured using the approach based on the actual asphalt layer thickness were closely related to the asphalt mixture density. Based on these results, a regression equation to determine the number of air voids in asphalt mixtures using the GPR test method was proposed. CONCLUSIONS: It was concluded that the number of air voids in an asphalt mixture can be calculated based on the dielectric constant of the mixture as determined by GPR testing. It was also found that the number of air voids was exponentially related to the dielectric constant, with the coefficient of determination, R2, being 0.74. These results suggest that the dielectric constant as determined by GPR testing can be used to improve the construction quality and maintenance of asphalt pavements.
        4,000원
        37.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to determine the optimal frequency of ground penetrating radar (GPR) testing for detecting the voids under the pavement. METHODS : In order to determine the optimal frequency of GPR testing for void detection, a full-scale test section was constructed to simulate the actual size of voids under the pavement. Voids of various sizes were created by inserting styrofoam at varying depths under the pavement. Subsequently, 250-, 500-, and 800-MHz ground-coupled GPR testing was conducted in the test section and the resulting GPR signals were recorded. The change in the amplitude of these signals was evaluated by varying the GPR frequency, void size, and void depth. The optimum frequency was determined from the amplitude of the signals. RESULTS: The capacity of GPR to detect voids under the pavement was evaluated by using three different ground-coupled GPR frequencies. In the case of the B-scan GPR data, a parabolic shape occurred in the vicinity of the voids. The maximum GPR amplitude in the A-scan data was used to quantitatively determine the void-detection capacity. CONCLUSIONS: The 250-MHz GPR testing enabled the detection of 10 out of 12 simulated voids, whereas the 500-MHz testing allowed the detection of only five. Furthermore, the amplitude of GPR detection associated with 250-MHz testing is significantly higher than that of 500-MHz testing. This indicates that 250-MHz GPR testing is well-suited for the detection of voids located at depths ranging from 0.5~2.0 m. Testing at frequencies lower than 250 MHz is recommended for void detection at depths greater than 2 m.
        4,000원
        38.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to propose a quality control and quality assurance method for use during asphalt pavement construction using non-destructive methods, such as ground penetrating radar (GPR) and an infrared (IR) camera. METHODS: A 1.0 GHz air-coupled GPR system was used to measure the thickness and in situ density of asphalt concrete overlay during the placement and compaction of the asphalt layer in two test construction sections. The in situ density of the asphalt layer was estimated based on the dielectric constant of the asphalt concrete, which was measured as the ratio of the amplitude of the surface reflection of the asphalt mat to that of a metal plate. In addition, an IR camera was used to monitor the surface temperature of the asphalt mat to ensure its uniformity, for both conventional asphalt concrete and fiber-reinforced asphalt (FRA) concrete. RESULTS: From the GPR test, the measured in situ air void of the asphalt concrete overlay gradually decreased from 12.6% at placement to 8.1% after five roller passes for conventional asphalt concrete, and from 10.7% to 5.9% for the FRA concrete. The thickness of the asphalt concrete overlay was reduced from 7.0 cm to 6.0 cm for the conventional material, and from 9.2 cm to 6.4 cm for the FRA concrete. From the IR camera measurements, the temperature differences in the asphalt mat ranged from 10℃ to 30 ℃ in the two test sections. CONCLUSIONS: During asphalt concrete construction, GPR and IR tests can be applicable for monitoring the changes in in situ density, thickness, and temperature differences of the overlay, which are the most important factors for quality control. For easier and more reliable quality control of asphalt overlay construction, it is better to use the thickness measurement from the GPR.
        4,000원
        39.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 X-band 레이더 기반 파고추정 방법의 비교연구에 대한 내용으로, 신호 대 잡음비 및 음영비를 이용하였다. 신호대 잡음비의 경우 기존 파고 추정을 위한 방법으로 널리 사용되고 있으며, 음영비의 경우 새로이 제시되는 방법이다. 본 연구에 사용된 레이더 영상의 경우 울산 주전해안에서 계측된 자료이며, 기상청 등표에서 계측된 해양기상정보와 비교하였다. 자료는 약 34일동안 계측된 자료를 비교하였으며, 동해안 태풍 진출 기간 자료를 확보하여 다양한 파고분포에 대한 결과를 검증하였다. 분석 결과 음영비를 이용한 파고추정의 경우, 부이와의 보정이 필요 없는 장점과 실시간 파고 계측의 가능성을 확인하였으며, 일부 풍속, 타 물체 탐지 등 레이더 영상의 외적 요소에 의한 오차 발생의 요인을 파악하였다.
        4,000원
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