• 제목/요약/키워드: Visibility measurement

검색결과 106건 처리시간 0.022초

MULTI-SENSOR DATA FUSION FOR FUTURE TELEMATICS APPLICATION

  • Kim, Seong-Baek;Lee, Seung-Yong;Choi, Ji-Hoon;Choi, Kyung-Ho;Jang, Byung-Tae
    • Journal of Astronomy and Space Sciences
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    • 제20권4호
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    • pp.359-364
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    • 2003
  • In this paper, we present multi-sensor data fusion for telematics application. Successful telematics can be realized through the integration of navigation and spatial information. The well-determined acquisition of vehicle's position plays a vital role in application service. The development of GPS is used to provide the navigation data, but the performance is limited in areas where poor satellite visibility environment exists. Hence, multi-sensor fusion including IMU (Inertial Measurement Unit), GPS(Global Positioning System), and DMI (Distance Measurement Indicator) is required to provide the vehicle's position to service provider and driver behind the wheel. The multi-sensor fusion is implemented via algorithm based on Kalman filtering technique. Navigation accuracy can be enhanced using this filtering approach. For the verification of fusion approach, land vehicle test was performed and the results were discussed. Results showed that the horizontal position errors were suppressed around 1 meter level accuracy under simulated non-GPS availability environment. Under normal GPS environment, the horizontal position errors were under 40㎝ in curve trajectory and 27㎝ in linear trajectory, which are definitely depending on vehicular dynamics.

이진 컴퓨터 형성 홀로그램을 이용한 비구면 형상 측정용 위상편이 회절격자 간섭계 (Diffraction grating interferometer for null testing of aspheric surface with binary amplitude CGH)

  • 황태준;김승우
    • 한국광학회지
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    • 제15권4호
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    • pp.313-320
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    • 2004
  • 위상편이 회절격자 간섭계와 이진 컴퓨터 형성 홀로그램을 제작하여 널 시스템을 구성하고 비구면형상 측정 시스템을 구축하였다. 제안하는 시스템은 비구면형상에 맞게 제작된 이진 컴퓨터 형상 홀로그램과 가시도가 조정된 위상편이 회절격자간섭계로 이루어져있다. 위상편이 회절격자간섭계는 회절격자의 홈 형상이나 간섭을 일으킬 측정광과 기준광을 바꿈으로써 가시도를 쉽게 조절할 수 있고, 높은 수준의 측정 정확도를 가지는 장점을 가지고 있다. 이진 컴퓨터 형성 홀로그램은 비구면의 정보를 통하여 컴퓨터로 수치모사한 후 전자-빔 리토그래피 장비로 제작할 수 있고, 위상편이 회절격자 간섭계, 비구면과 함께 자동곡률측정 방식으로 설치된다. 간섭계와 홀로그램을 제작한 후 비구면을 측정, 실험을 수행하고 시스템을 평가하였다.

위상이동법과 시간평균법의 면내변위 측정 비교 (Comparison of In-Plane Measurement of Phase-Shifting with Time-Average Method)

  • 김경석;김동일;정현철;강기수;이찬우;양승필;장순석
    • 한국정밀공학회지
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    • 제16권10호
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    • pp.53-58
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    • 1999
  • Even I the Electronic Speckle Pattern Interferometry(ESPI) method that measure the strain of object within wavelength of light is less visibility than Holographic Interferometry(HI) method, the merits of application, convenience and time-save have made the method practical in industry. However, the existing ESPI methods that are based on dual-exposure, real-time and time-average method have difficulties for accurate measurement, due to irregular intensity and shake of phase. Recently, in order to solve this problem, phase shifting method have been proposed. In this method, the path of reference light in interference is shifted to make improvement in distinction and precision. But this method includes too many noise, caused by the problem of relationship between object and phase. Therefore, a method to reduce noise muse be introduced. In this paper, least square fitting method is proposed. As results, the phase-map is influenced by precise phase shifting and current of notes and speckle pattern obtained by phase shifting method is improved on the existing method driven from time-average method.

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다층 나노임프린트 리소그래피 시스템 및 나노측정기술 (Technology for the Multi-layer Nanoimprint Lithography Equipments and Nanoscale Measurement)

  • 이재종;최기봉;김기홍;임형준
    • 진공이야기
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    • 제2권1호
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    • pp.10-16
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    • 2015
  • With the recognition of nanotechnology as one of the future strategic technologies, the R&D efforts have been performed under exclusive supports of governments and private sectors. At present, nanotechnology is at the focus of research and public attention in almost every advanced country including USA, Japan, and many others in EU. Keeping tracks of such technical trends, center for nanoscale mechatronics and manufacturing (CNMM) was established in 2002 as a part of national nanotechnology promotion policy led by ministry of science and technology (MOST) in Korea. It will hold widespread potential applications in electronics, optical electronics, biotechnology, micro systems, etc, with the promises of commercial visibility and competitiveness. In this paper, wafer scale multilayer nanoimprint lithography technology which is well-known the next generation lithography, roll-typed nanoimprint lithography (R-NIL), roll-typed liquid transfer imprint lithography (R-LTIL), the key technology for nanomanufacturing and nanoscale measurement technology will be introduced. Additionally, its applications and some achievements such as solar cell, biosensor, hard disk drive, and MOSFET, etc by means of the developed multilayer nanoimprint lithography system are introduced.

Functional MRI를 이용한 학습집중력 향상 시트 개발 (Usefulness of Functional MRI for the study of concentration sheet)

  • 김창규
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2009년도 춘계학술발표논문집
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    • pp.13-17
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    • 2009
  • 본 논문에서는 학습집중력을 향상 시킬 수 있는 시트를 제작 하였다. 학습집중력의 향상을 입증하기 위하여 인체내에 존재하고 있는 조영제를 이용하여 공간적 시간적 해상도가 뛰어나고 비침습적으로 뇌기능을 측정할 수 있는 기능적 자기공명영상을 획득하고 뇌파측정을 한 결과 기억작용과 관련 있는 전두엽 부근의 뇌혈류량의 활성화를 확인할 수 있었고 뇌파 측정 분석결과 절대알파파와 절대베타파의 비율에서 유의할 만한 변화를 확인하였다. 기능적자기공명 영상은 뇌의 생리기능적 역할을 규명 의학적으로 수술 전후 장애를 방지하고 예방하는데 활용하고 있으며 뇌신경망의 가시화로 학습 집중력 등과 같은 뇌와 관련된 제품을 개발하는데 많은 연구가 이루어질 것이다.

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연속파 레이저 스페클 사진법(寫眞法)과 화상처리(畵像處理)에 의한 면내섭위(面內燮位) 측정(測定)에 관한 연구(硏究) (A Study of Measurement of In-plane Displacement by CW Laser Speckle Photography and Image Processing)

  • 김경석;나기대;김택현;정낙규;김충원
    • 비파괴검사학회지
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    • 제10권1호
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    • pp.47-55
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    • 1990
  • This paper presents experimental results which explore the capability of a CW laser speckle photography for tile measurement of in-plane displacement at high temperature. The serious restrictions on the application of the method seem to be the ambient air turbulence and the change of surface texture caused by the oxidation, as they tend to decorrelate the double exposured speckle patterns. In order to assess only the effect of air turbulence, a ceramics-coated stainless steel plate is heated in air and Ar-laser specklegrams are made with combination of temperature and lateral translation displacement. The slight reduction in visibility of Young's fringes is observed at $1000^{\circ}C$. The analyses of Young's fringes are carried out by a image processing system using a TV-camera and computers, and the result agrees well with the micrometer reading. Futhermore, uncoated stainless steel and Hastelloy X plates are tested and the effect of oxidation is also evaluated. The experimental results demonstrate that a CW laser speckle photography is applicable at temperatures up to $1000^{\circ}C$.

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Ray-Tracing 알고리즘을 이용한 CCTV배치 평가시뮬레이션 (Simulation to Evaluate CCTV Positioning in Use of Ray-Tracing Algorithm)

  • 김석태;안상욱
    • 한국실내디자인학회논문집
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    • 제22권6호
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    • pp.40-48
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    • 2013
  • Utilization of CCTV in crime prevention for public safety is accepted as the most effective measure in terms of crime prevention and control. Also, it is frequently used as a device that shows evidence of an unexpected situation or record on public social relationship. However, it is rare to find a study that qualitatively accessed the monitoring performance of a certain space depending on the choice and positioning of CCTVs. Thus, this study suggested a technology that can quantitatively compare and assess the monitoring performance of CCTVs depending on view angle and effective sight range of cameras as well as the monitoring performance depending on positioning measures. For the analysis, the concept of 3-dimensional surveillance field in the form of a frustum was suggested while deriving 3-dimensional range of sight and quantitative monitoring performance by applying Isovist theory. For the analysis technology, space of analysis subject, point of view (camera), and target point (measurement node) were installed at a 3-dimensional space and in use of ray-tracing algorithm, the line segment that was visually connected between the point of view and target point was extracted and accumulated. For such verification, analysis application was constructed and then applied to four alternative models on view angle and distance as well as four alternatives on positioning in order to verify its efficacy. Through the experiment, it was possible to compare and assess visibility depending on alternatives while quantifying the results by understanding the shadow areas beyond the monitoring range.

백색광 위상천이 간섭계를 위한 개선된 삼차원 형상 측정 방법 (Improved 3D Shape Measurement Scheme for White Light Phase Shifting Interferometry)

  • 김경일;이동열;고윤호
    • 대한전자공학회논문지SP
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    • 제47권2호
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    • pp.51-60
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    • 2010
  • 본 논문에서는 백색광 위상천이 간섭계에서 향상된 3차원 형상 정보를 보다 빠르게 얻을 수 있는 새로운 방법을 제안한다. 백색광 위상천이 간섭계는 초정밀 제품의 형상 측정에 사용되는 유용한 방법이다. 첫째, 가시도 함수를 포함하는 간섭신호로부터 3차원 높이 정보를 신속하게 계산할 수 있는 가시도 유효 검출 구간 설정 방법을 제안한다. 둘째, 기존의 백색광 위상천이 간섭계에서 발생하는 전역 기울어짐 현상을 해결하기 위하여 바닥면 데이터 자동 추출 방법과 이를 이용한 최소 제곱 근사화 기반의 바닥 평변 추정 방법을 제안한다. 셋째, 높이의 변화가 큰 경계영역에서의 형상 왜곡인 bat-wing effect를 제거하기 위한 적응 필터 방법을 제안한다. 실험을 통해 제안하는 방법이 기존의 백색광 위상천이 간섭법의 성능을 보다 향상시킴을 보인다.

조직구성원의 정보보안 준수 및 미준수 원인에 대한 연구 (A study on the information security compliance and non-compliance causes of organization employees)

  • 황인호;허성호
    • 한국융합학회논문지
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    • 제11권9호
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    • pp.229-242
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    • 2020
  • 본 연구의 목적은 정보보안 준수의도에 영향을 주는 긍정적, 부정적 측면의 환경적 요인을 제시하고, 개인의 보안 준수의도와의 영향관계를 찾는 것이다. 연구대상은 정보보안 정책 및 기술을 적용하는 조직의 구성원들이며, 설문 조사를 통하여 유효표본을 확보하였다. 분석과정에서 구조방정식모델링을 통해 연구모델에 대한 검증을 하였다. 측정변수는 정보보안 정책, 정보보안 시스템, 정보보안 기술적 지원, 업무장애, 비가시성, 조직몰입, 준수의도로 구성하여 분석에 활용하였다. 결과는 보안 준수요인인 정책, 시스템, 기술적 지원과 미준수 요인인 업무 장애가 각각 조직몰입에 영향을 주었으며, 준수의도로 이어지는 것을 확인하였다. 연구 모델의 검증 결과를 토대로 조직의 정보보안 준수 수준 향상을 위한 구성원들의 보안 준수 전략 수립의 방향성을 제시하였다.

SIMULATION OF COSMIC MICROWAVE BACKGROUND POLARIZATION FIELDS FOR AMiBA EXPERIMENT

  • PARK CHAN-GYUNG;PARK CHANGBOM
    • 천문학회지
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    • 제35권2호
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    • pp.67-73
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    • 2002
  • We have made a topological study of cosmic microwave background (CMB) polarization maps by simulating the AMiBA experiment results. A ACDM CMB sky is adopted to make mock interferometric observations designed for the AMiBA experiment. CMB polarization fields are reconstructed from the AMiBA mock visibility data using the maximum entropy method. We have also considered effects of Galactic foregrounds on the CMB polarization fields. The genus statistic is calculated from the simulated Q and U polarization maps, where Q and U are Stokes parameters. Our study shows that the Galactic foreground emission, even at low Galactic latitude, is expected to have small effects on the CMB polarization field. Increasing survey area and integration time is essential to detect non-Gaussian signals of cosmological origin through genus measurement.