• 한국지반환경공학회 논문집
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• 제9권3호
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• pp.29-34
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• 2008

한국건설기술연구원(KICT)에서는 트리플 코어 바렐의 원리를 적용하여 기존의 연약지반 뿐만 아니라 사질토 및 풍화토 지대에도 적용이 기능한 대구경 샘플러를 개발하였다. 특별히 제작된 시료 절단 및 추출 장치는 다양한 종류의 채취 시료에 적용하여 시료의 교란을 최대한 방지 할 수 있도록 고안되었다. 샘플러 두부에는 적절한 강성의 스프링을 설치하여 슈(shoe)와 비트(bit) 사이의 거리가 변화하도록 하여 대상지반의 강성에 맞추어 효과적인 시료채취가 가능하도록 하였다. 대구경 샘플러의 적용성을 확인하기 위하여 일반적으로 시용되는 피스톤 샘플러와 대구 경 샘플러를 이용해 여러 대상지반에서 채취한 시료의 교란도를 비교 분석하였으며, 다양한 공학적 특성 또한 비교 분석 하였다.

• 한국측량학회지
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• 제40권1호
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• pp.1-14
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• 2022

굴착 현장에서 신속·정확·안전한 측량을 위해 본 연구에서는 드론을 이용한 지하 시설물 측량의 적용 가능성 및 3D 시각화의 기대효과를 다음과 같이 도출하였다. Phantom4 Pro 20MP의 드론으로 30m의 비행 고도, 중복도 85%의 비행계획으로 0.85mm의 GSD (Ground Sampling Distance)값을 확보하였고, GCP (Groud Control Point)4점과 검사점 2점을 계산하여 기준점에 대하여 7.3mm, 검사점은 11mm의 성과를 취득할 수 있었다. 저가의 드론으로 측량할 경우 GCP의 중요성이 확인되었으며, 지상 기준점이 없는 경우, X값의 오차 범위는 -81.2cm에서 +90.0cm, Y값의 오차 범위는 +6.8cm에서 155.9 cm 값을 도출하였다. Pix4D 프로그램을 이용하여 포인트 클라우드 데이터를 분류하였다. 지하 시설물 데이터와 도로 포장면의 데이터를 분류하고, 중첩과정을 통해 실제 모형의 도로와 지하 시설물의 데이터를 3D 시각화하였다. 중첩된 포인트 클라우드 데이터는 Open Source 프로그램인 CloudCompare를 통해 사용자가 원하는 장소의 위치와 심도 정보를 확인할 수 있게 되었다. 본 연구결과로 지하 시설물 측량의 새로운 패러다임으로 자리매김하게 될 것이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1052-1054
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• 2003

RAZAKSAT is a second micro-satellite mission by Malaysian Satellite Program and is expected for launch in June 2004. Designed to orbit the earth at low-equatorial orbit, RAZAKSAT will meet Malaysia’s immediate needs to rapid data acquisition (real time and more repetitions) to address many operational issues of remote sensing applications, which require availability of current data sets. RAZAKSAT will be among the first remote sensing satellite to orbit the earth at low inclination along the equator, 9$^{\circ}$ with 685km altitude, hence, allows optimal geographical information and environment change within equatorial region be observed with a unique revisit characteristics. The satellite primary payload is MAC, a push-broom type camera with 2.5m of ground sampling distance (GSD) in panchromatic band and 5m of GSD in four multi-spectral bands. This paper describes on the variation of illumination anticipated from simulated RAZAKSAT image, examine its implication to its ground leaving radiances for major applications.

• 한국광학회지
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• 제12권5호
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• pp.382-388
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• 2001

1999년 5월 26일 발사되었던 우리별 3호 인공위성에는 지구관측 전자광학 카메라가 탐재되어 있다. MEIS는 직경 95 mm Mangin 망원경으로 고도 720 km에서 13.8 m의 지상화소로 48km의 폭을 3개의 서로 다른 광 대역에서 관측한다. 본 논문에서는 우리별 3호 카메라의 설계와 제작/조립 및 시험결과를 비교 분석하고, 발사후의 운영에 관련된 문제점을 논하였다.

• Journal of Positioning, Navigation, and Timing
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• 제5권1호
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• pp.29-36
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• 2016

In this paper, performance on receivers of multilateration (MLAT) system that uses ADS-B signal, which is recently becoming popular, was analyzed to overcome shortcomings of existing aircraft flight control systems or reinforce the capabilities. A link budget was analyzed using a channel model in the airport environment with regard to Local Area Multilateration (LAM) for ground-controlled landing around the airport. In order to detect signals that arrived at the receiver successfully, sensitivity of receiver was analyzed using a signal-to-noise ratio (SNR) worksheet, and a method that improves accuracy of the distance measurement was proposed by adopting a peak estimation using sampling signals. Through simulations, optimum specifications of receivers were analyzed to have high precision positioning of LAM, and accuracy of LAM distance measurements was presented.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 춘계학술대회 논문집
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• pp.1-8
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens a detecting unit with polygon mirror and CCD array sensor. and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultanilusly monitor the state of the grind wheel. The experimental results, showed that the increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min. the feed rate is 0.2m/min-0.9m/min, the dressing speed is 0.2mm/rev-0.4mm/rev, the stylus method and the in-process method can be obtained the same results. thus under limited working conditions. using the proposed system. the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• 지구물리와물리탐사
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• 제7권3호
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• pp.197-206
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• 2004

지하수 과잉양수에 의해 충적층 지반의 미세한 변위가 나타나는 경우는 대상지역 소유역내의 물수지 불균형이 주요한 원인으로, 이러한 미세변위를 효과적으로 계측하기 위해서는 대상지역내 지반의 대표적인 지점들에서 물수지 측정과 연계된 침하량의 장기 모니터링 방법이 효율적이다. 이 연구에서는 롬층과 모래층으로 구성된 지반에 대하여 시추조사를 이용한 3차원 토양단면도를 작성한 후, 2차원 전기비저항 탐사로부터 얻어진 수리지질구조를 이용하여 개념모델을 구성하였다. 이러한 개념모델과 다양한 수리지질조사 결과를 기초로 지하수 유동모델링과 지반침하 모델링을 수행하여 개념모델의 정확성을 검증한 결과, 롬층과 모래층으로 구성된 지반에서 미세 지반변형과 연관된 수리지질 구조를 해석하는 경우에는 hand auger를 이용한 시추조사와 전극간격을 짧게 한 2차원 전기비저항 탐사법을 함께 적용하는 것이 유용함을 확인하였다.

• 한국안전학회지
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• 제10권3호
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• pp.30-41
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• 1995

This paper proposed a simple method for measuring surface roughness of ground surface. Utilizing non-contact in-process measuring system using the diode laser. The measurement system is consisted of a laser unit with a diode laser and a cylindrical lens, a detecting unit with polygon mirror and CCD array sensor, and a signal processing unit with a computer and device. During operation, this measuring system can provide information on surface roughness in the measuring distance with a single sampling and simultaniously monitor the state of the grind wheel. The experimental results, showed that the Increase of the feed rate and the dressing speed an caused increase in the surface roughness and when the surface roughness is 4Rmax-10Rmax, the cutting speed is 1653m/min-1665m/min, the table speed is 0.2n1/min -0.9m/min, the dressing speed is 0.2mm/rev～0.4mm/rev, the stylus method and the in-process method can be obtained the same results. Thus, under limited working conditions, using the proposed system, the surface roughness of the ground surface during cylindrical grinding can be obtained through the in-process measurement method using the diode laser.

• Current Optics and Photonics
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• 제7권5호
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• pp.545-556
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• 2023

This paper introduces volume-sharing multi-aperture imaging (VMAI), a potential approach proposed for volume reduction in space-borne imagers, with the aim of achieving high-resolution ground spatial imagery using deep learning methods, with reduced volume compared to conventional approaches. As an intermediate step in the VMAI payload development, we present a phase-1 design targeting a 1-meter ground sampling distance (GSD) at 500 km altitude. Although its optical imaging capability does not surpass conventional approaches, it remains attractive for specific applications on small satellite platforms, particularly surveillance missions. The design integrates one wide-field and three narrow-field cameras with volume sharing and no optical interference. Capturing independent images from the four cameras, the payload emulates a large circular aperture to address diffraction and synthesizes high-resolution images using deep learning. Computational simulations validated the VMAI approach, while addressing challenges like lower signal-to-noise (SNR) values resulting from aperture segmentation. Future work will focus on further reducing the volume and refining SNR management.

• 한국측량학회지
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• 제30권6_2호
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• pp.643-651
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• 2012

Object recognition belongs to high-level processing that is one of the difficult and challenging tasks in computer vision. Digital photogrammetry based on the computer vision paradigm has begun to emerge in the middle of 1980s. However, the ultimate goal of digital photogrammetry - intelligent and autonomous processing of surface reconstruction - is not achieved yet. Object recognition requires a robust shape description about objects. However, most of the shape descriptors aim to apply 2D space for image data. Therefore, such descriptors have to be extended to deal with 3D data such as LiDAR(Light Detection and Ranging) data obtained from ALS(Airborne Laser Scanner) system. This paper introduces extension of chain code to 3D object space with hierarchical approach for segmenting point cloud data. The experiment demonstrates effectiveness and robustness of the proposed method for shape description and point cloud data segmentation. Geometric characteristics of various roof types are well described that will be eventually base for the object modeling. Segmentation accuracy of the simulated data was evaluated by measuring coordinates of the corners on the segmented patch boundaries. The overall RMSE(Root Mean Square Error) is equivalent to the average distance between points, i.e., GSD(Ground Sampling Distance).