• 센서학회지
• /
• 제19권2호
• /
• pp.99-111
• /
• 2010

This paper proposes an efficient hardware architecture to estimate disparities between 2D images for generating 3D depth images in a stereo vision system. Stereo matching methods are classified into global and local methods. The local matching method uses the cost functions based on pixel windows such as SAD(sum of absolute difference), SSD(sum of squared difference) and NCC(normalized cross correlation). The NCC-based cost function is less susceptible to differences in noise and lighting condition between left and right images than the subtraction-based functions such as SAD and SSD, and for this reason, the NCC is preferred to the other functions. However, software-based implementations are not adequate for the NCC-based real-time stereo matching, due to its numerous complex operations. Therefore, we propose a fast pipelined hardware architecture suitable for real-time operations of the NCC function. By adopting a block-based box-filtering scheme to perform NCC operations in parallel, the proposed architecture improves processing speed compared with the previous researches. In this architecture, it takes almost the same number of cycles to process all the pixels, irrespective of the window size. Also, the simulation results show that its disparity estimation has low error rate.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
• /
• pp.344-347
• /
• 2008

Ocean surface waves may be modified by ocean current and their observation may be severely distorted if the observer is on a moving platform with changing speed. Tidal current near a sill varies inversely with the water depth, and results spatially inhomogeneous modulation on the surface waves near the sill. For waves propagating upstream, they will encounter stronger current before reaching the sill, and therefore, they will shorten their wavelength with frequency unchanged, increase its amplitude, and it may break if the wave height is larger than 1/7 of the wavelength. These small scale (${\sim}$ 1 km changes is not suitable for satellite radar observation. Spatial distribution of wave-height spectra S(x, y) can not be acquired from wave gauges that are designed for collecting 2-D wave spectra at fixed locations, nor from satellite radar image which is more suitable for observing long swells. Optical images collected from cameras on-board a ship, over high-ground, or onboard an unmanned auto-piloting vehicle (UAV) may have pixel size that is small enough to resolve decimeter-scale short gravity waves. If diffuse sky light is the only source of lighting and it is uniform in camera-viewing directions, then the image intensity is proportional to the surface reflectance R(x, y) of diffuse light, and R is directly related to the surface slope. The slope spectrum and wave-height spectra S(x, y) may then be derived from R(x, y). The results are compared with the in situ measurement of wave spectra over Keelung Sill from a research vessel. The application of this method is for analysis and interpretation of satellite images on studies of current and wave interaction that often require fine scale information of wave-height spectra S(x, y) that changes dynamically with time and space.

• 한국해양공학회지
• /
• 제32권4호
• /
• pp.279-286
• /
• 2018

The use of eco-friendly energy in the offshore plant system is expanding because conventional generators are operated by fossil fuel or natural gas. Eco-friendly energy, which replaces existing power generation methods, should be capable of generating the power for lighting protection equipment, airborne fault indication, parameter measurement, and others. Most of the eco-friendly energy used in offshore plant facilities is solar and wind power. In the case of using photovoltaic power, because the structure must be constructed based as flat solar panels, it can be damaged easily by the wind. Therefore, there is a need for a new generation system composed of a spherical structure that does not require a separate structure and is less influenced by the wind. Considering these characteristics, in this study we designed, fabricated, and tested a unit that could provide the most efficient spherical photovoltaic power generation considering wind direction and wind pressure. Our test results indicated that the proposed system reduced costs because it did not require any separate structure, used eco-friendly energy, reduced carbon dioxide emissions, and expanded the proportion of eco-friendly energy use by offshore plant facilities.

• 한국전기전자재료학회논문지
• /
• 제17권5호
• /
• pp.552-559
• /
• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, the advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The ring-shaped electrodeless lamp is intended as a high efficiency replacement for the incandescent reflector lamp in many applications. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, maxwell 3D finite element analysis program(Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250 KHz and some specific conditions. The optical characteristics were measured luminance and a temperature and an optical spectrum distribution for 10 min in a one minute interval at the same time. With a goal of finding alternative materials, we show measurement results of electrical characteristics of a ring-shaped electrodeless fluorescent lamp as a function of frequency and the number of coil turns using a highly permeable($\mu$$_{r}$(equation omitted) 2,000) Mn-Zn ferrite. These results are compared with those of conventional ring-shaped electrodeless fluorescent lamp. It is found that the resistance, inductance and impedance are increased while the quality factor decreases as frequency increases.s.

• 한국항만경제학회지
• /
• 제28권1호
• /
• pp.105-122
• /
• 2012

항만에서 운용되는 선박, 트럭, 기차, 하역장비들이 배출하는 온실가스는 현장 근로자들뿐만 아니라 인근 지역민들의 건강 및 생활환경을 악화시키고 있다. 세계 주요항만 대기오염 문제 해결을 위해 다양한 노력을 하고 있다. 본 연구는 항만 중 온실가스 배출량 비중이 가장 높은 컨테이너터미널을 대상으로 온실가스 저감방안에 대한 연구를 하였다. 연구를 위해 먼저 저감대안들을 추출하였고 이에 대한 중요 우선순위를 결정하는 계층적 의사결정 모델 제시와 실증분석을 실시하였다. 컨테이너터미널 온실가스 저감대안을 선정 하는데 있어 5가지 요소 기준을 적용하였고, 실무자와 전문가의 의견을 수렴하여 대안들을 추출하였다. 또한 선정된 온실가스 저감방안에 대한 평가영역과 요소들을 평가하는데 있어 언어척도의 애매모호하고 불확실한 상황을 고려하여 퍼지모형과 계층적분석방법(Analytic Hierarchy Process)을 결합한 Fuzzy-AHP을 적용하였다. 연구결과 컨테이너터미널 온실가스 저감방안의 측정영역에 대한 중요도 평가는 장비영역이 가장 높았고, 다음으로 운영영역과 에너지영역 순으로 나타났다. 온실가스 저감대안들의 전체 우선순위를 보면 전기T/C 도입이 우선순위가 가장 높은 것으로 분석되었다. 다음으로 Y/T하이브리드 개조, AMP도입, MLS 도입 순으로 나타났다.

• 조명전기설비학회논문지
• /
• 제23권2호
• /
• pp.36-44
• /
• 2009

본 연구의 목적은 한국의 궁궐건축 빛환경 성능을 측정하고 분석하고자 하며, 현재까지 가장 보존이 잘되어 있는 창덕궁 낙선재를 선택하였다. 조도 분포와 휘도 분포를 측정한 결과, 처마에 의해 직사일광의 유입이 차단되는 것을 알 수 있었으며, 밝은 색의 마당 등에 의한 반사광이 실내 깊숙이 유입되는 것을 알 수 있었다. 그리고 창호의 겹 수가 증가함에 따라 실내의 주광 분포는 균일하고 변화가 적음을 알 수 있었다. 또한 창호의 표면의 휘도분포는 윗부분 보다 아랫부분의 휘도가 높게 나타났으며, 이는 처마에 의해 직사일광이 차단되기 때문이다. 본 연구는 궁궐건축의 빛 환경 특성과 현대건축에서의 활용에 대한 기초자료로 활용이 가능하다.

• 한국전기전자재료학회논문지
• /
• 제26권8호
• /
• pp.614-619
• /
• 2013

Recently, remote phosphor is reported for white LED enhancing of phosphor efficiency compared with conventional phosphor-based W-LED. In this study, Remote phosphor was produced by screen printing coating on glass substrate with phosphor contents rated paste and heat treatment. The paste consists of phosphor, lowest softening glass frit and organic binders. Remote phosphor can be well controlled by varying the phosphor content rated paste. After mounting remote phosphor on top of blue LED chip, CCT, CRI, and luminance efficiency were measured. The measurement results showed that CCT, CRI, and luminance efficiency were 6,645, 68, and 1,16l m/W in phosphor 80 wt.% remote phosphor sintered at $600^{\circ}C$.

• 한국정보통신학회논문지
• /
• 제22권1호
• /
• pp.140-146
• /
• 2018

최근 실내조명으로 사용하는 LED(Light Emitting Diode)와 무선통신 기술을 융합한 가시광통신이 주목받고 있다. 하지만 가시광 통신은 광 신호를 측정할 수 있는 커버리지 내에서만 통신이 가능하고, 비가시선 영역에서 통신이 단절되는 현상이 발생한다. 본 논문에서는 가시광 통신의 커버리지 확장과 비가시선 영역에서 통신 단절 현상 개선을 위해 VLC(Visible Light Communication) 릴레이 모듈을 제안한다. 제안하는 VLC 릴레이 모듈은 송신기로부터 전달받은 패킷을 VLC 릴레이 모듈 및 수신기로 전송한다. 1개의 VLC 송신기와 3개의 VLC 릴레이 모듈을 설치하여 실험을 진행하였으며, VLC 릴레이 모듈의 증가에 따른 통신 커버리지 확장과 비가시선 영역에서 통신 단절 현상 개선을 확인하였다. 또한, 이중 샘플링 기법을 사용하여 광 신호 측정 성능이 2.4배 향상됨을 확인하였다.

• 한국통신학회논문지
• /
• 제40권2호
• /
• pp.390-396
• /
• 2015

무선인터넷과 이동통신 기술의 발달 및 스마트폰의 급속한 확산으로 인해 사용자의 현재 및 과거의 위치 정보를 사용하여 다양한 부가정보를 제공하는 위치기반 서비스에 대한 관심이 급증하고 있다. 위치기반 서비스의 본격적인 활성화를 위해서는 정확한 측위가 기본이 된다. GPS (Global Positioning System)와 WPS (Wi-Fi Positioing System)가 상용화 되면서 측위 기술에 일대 혁신을 가져왔으나 실내환경에서 많은 제약을 가졌고 스마트폰에 일반적으로 설치되는 관성센서 (IMU: Inertia Motion Unit)를 사용한 네비게이션 (Navigation)기술을 실내 환경에서 응용하는 시도도 일정부분 성과를 거두었다. LED 조명을 이용한 실내 측위는 LED 조명으로부터 특정 신호를 수신하여 해석을 하는 Li-Fi (Light Fidelity) 통신의 부가 서비스의 한 형태로 조명 받았으나, LED 조명으로부터 신호를 수신하기 위한 수신기를 갖추어야 하는 실제적인 문제가 있다. 본 논문에서는 부가 장비 없이 스마트폰의 이미지 센서만을 이용하여 LED 조명으로부터 신호를 수신하여 해석하는 방식을 제시하고 이를 실내 측위에 이용하는 응용 서비스 기술을 제안한다.

• 한국안전학회지
• /
• 제10권3호
• /
• pp.96-105
• /
• 1995

The better industry develops, the more spaces need but in the limited area. Most building become larger and more complicated if the more spaces need in the constant area. And this leads to do underground work in long period generally six(6) months for 6 basement stories due to the selection of TOP DOWN technique. Working environment in this underground area can be problems and should not be overlooked, because air quality in underground spaces become quickly worse. Recently, department name to control construction safety has been changed to ENVIRONMENT & SAFETY TEAM from SAFETY TEAM. This means that it is very important to control against environmental condition at site so much. Overall construction work as well as underground work should conform to the requirement of working environment, particularly against inhabitants around the construction area. Strut protection, one of earth protection method, in case to 40m long strut may become weaker due to thermal stress or its longitudinally compressive strain and the another one, earth anchor protection may not be applied to the site In case of encroaching on vertical underground borderline because of regulation to prohibit it. It is necessary that TOP DOWN technique should be introduced in order to solve the external and internal problem of the site such as difficulty level of the work, potential danger with excavating depth, and shortening workperiod. It is needed that improving way of working condition should be shown and simplified computer simulation program should be also provided for checking pollution level & ventilation, excluding of lighting problem here. Results measured with conformance to the Regulation for Working Environment Measurement, enforced by Ministry of Labor have been applied to the computer program developed here. Sample air taken at unit workplace which was considered as exposing condition of pollutant at breathing point and within a range of behavior of the workers, Identified exposing group in underground work, using Moded Flow Life Finally, three types of ventilation system, type I with blower & ventilator, type II natural supply with mechanical ventilation system, and type I mechanical ventilation with Drivent Fan Unit System are selected for this study.