• 한국음향학회지
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• 제20권8호
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• pp.67-73
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• 2001

최근 수중음향에 대한 관심은 천해와 같은 복잡한 음파의 상호작용과 경계조건이 부정확한 해양환경으로 이동하고 있다. 천해 음향전파에 의해서 발생하는 어려움을 극복하기 위한 방법으로 음원의 광대역 스펙트럼에서 얻어지는 정보를 사용하여 견고성과 신뢰성을 증가시키는 광대역 정합장처리 기법이 사용된다. 본 논문에서는 협대역에서의 음장의 공간 일관성을 확장하여 다중 주파수를 사용한 주파수-공간 일관성 광대역 프로세서를 제안하였고, 이 프로세서를 실제 광대역 이동음원에 적용하여 음원위치추적을 수행하였다. 제안된 일관성 프로세서는 음원의 정위치 추정확률이 높았으며, 특히 정합장출력의 부엽준위에서 비일관성 프로세서와 비교해 일관성 프로세서가 상당히 낮은 준위를 나타내었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.571-575
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• 2002

Generation of electrical energy faces many problems today. Solar power converters were used to convert the electrical energy from the solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC-DC converters in a solar energy system to investigate the performance of the converters. A DC-DC converter can be commonly used to control the power flow from solar cell to load and to achieve maximum power point tracking(MPPT), DC-AC converter can also be used to modulate the DC power to AC power being applied on common utility load. A DC-DC converter is used to boost the solar cell voltage to constant 360(V) DC link and to ensure operation at the maximum power point tracking, If a wide input voltage range has to be covered a boost converter is required. In this paper, author described that simulation and experimental results of PV system contain solar modules, a DC-DC converter(boost type chopper), a DC-AC converter (3-phase inverter) and resistive loads.

• Journal of Electrical Engineering and Technology
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• 제5권4호
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• pp.606-613
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• 2010

This paper proposes a novel current-based maximum power point tracking (CMPPT) method for a single-phase photovoltaic power conditioning system (PV PCS) by using a modified incremental conductance method. The CMPPT method simplifies the entire control structure of the power conditioning system and uses an inherent current source characteristic of solar cell arrays. Therefore, it exhibits robust and fast response under a rapidly changing environmental condition. Digital phase locked loop technique using an all-pass filter is also introduced to detect the phase of grid voltage, as well as the peak voltage. Controllers of dc/dc boost converter, dc-link voltage, and dc/ac inverter are designed for coordinated operation. Furthermore, a current control using a pseudo synchronous d-q transformation is employed for grid current control with unity power factor. A 3 kW prototype PV PCS is built, and its experimental results are given to verify the effectiveness of the proposed control schemes.

• Journal of Power Electronics
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• 제16권6호
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• pp.2202-2211
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• 2016

In certain applications, such as IPT-based EV charger (IPTEC), any variation in alignment and distance between pickup and charger primary leads to a change in leakage and magnetic impedance magnitudes. The power transmission capacity is not always at the maximum level because of these variations. This study proposes a new low-cost tracking method that achieves the Maximum Inductive Power Transmission Capacity (MIPTC). Furthermore, in the proposed method, the exchange of information between load and source is not required. For an application such as IPTEC, the load detected by the IPTEC varies continuously with time because of the change in state of the charge. This load variation causes a significant variation in IPT resonant circuit voltage gain. However, the optimized charging output voltage should be kept constant. From the analysis of the behavior of the IPT circuit at different working frequencies and load conditions, a MIPTC operation point that is independent of load condition can be identified. Finally, the experimental results of a developed prototype IPT circuit test show the performance of the proposed method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권4호
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• pp.269-275
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• 2004

Photovoltaic(PV) system has been studied and watched with keen interest due to a clean and renewable power source. But, the output power of PV system is not only unstable but uncontrollable, because the maximum power point tracking (MPPT) of PV system is still hard with the tracking failure under the sudden fluctuation of irradiance. Authors suggest that the optimal voltage for MPPT be obtained by only solar cell temperature. Having an eye on that the optimal voltage point of solar cell is in proportion to its panel temperature, with operating the power converter whose operating point keeps its input voltage to the optimal voltage imagined by the surface's temperature of PV panel, the maximum power point becomes tenderly possible to be tracked. In order to confirm the availability of the proposed control scheme. And both control methods are simulated not only on the various angle of sampling time of switching control, but also with the real field weather condition. As the results of that, the conversion efficiency between PV panel and converter of the proposed control scheme was much better than that of the power comparison MPPT control, and what is better, the output voltage of PV panel was extremely in stable when the optimal voltage for MPPT is obtained by only solar cell temperature.

• 한국통신학회논문지
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• 제38C권9호
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• pp.781-786
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• 2013

Multiplexing information over parallel data channels based on RF MIMO concept is possible to achieve considerable data rates over large transmission ranges with just a single transmitting element. Visual multiplexing MIMO techniques will send independent streams of bits using the multiple elements of the light transmitter array and recording over a group of camera pixels can further enhance the data rates. The proposed system is a combination of the reliance on computer vision algorithms for tracking and OOK cell frame modulation. LED array are controlled to transmit message in the form of digital information using ON-OFF signaling with ON-OFF pulses (ON = bit 1, OFF = bit 0). A camera captures image frames of the array which are then individually processed and sequentially decoded to retrieve data. To demodulated data transmission, a motion tracking algorithm is implemented in OpenCV (Open source Computer Vision library) to classify the transmission pattern. One of the most advantages of proposed architecture is Computer Vision (CV) based image analysis techniques which can be used to spatially separate signals and remove interferences from ambient light. It will be the future challenges and opportunities for mobile communication networking research.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.207-209
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• 2019

This paper proposes a grid-tied photovoltaic (PV) system, consisting of Voltage-fed dual-active-bridge (DAB) dc-dc converter with single phase inverter. The proposed converter allows a small dc-link capacitor, so that system reliability can be improved by replacing electrolytic capacitors with film capacitors. The double line frequency free maximum power point tracking (MPPT) is also realized in the proposed converter by using Ripple Correlation method. First of all, to eliminate the double line frequency ripple which influence the reduction of DC source capacitance, control is developed. Then, a designing of Current control in DQ frame is analyzed and to fulfill the international harmonics standards such as IEEE 519 and P1547, $3^{rd}$ harmonic in the grid is directly compensated by the feedforward terms generated by the PR controller with the grid current in stationary frame to achieve desire Total Harmonic Distortion (THD). 5-kW PV converter and inverter module with a small dc-link film capacitor was built in the laboratory with the proposed control and MPPT algorithm. Experimental results are given to validate the converter performance.

• 대한원격탐사학회지
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• 제38권1호
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• pp.1-20
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• 2022

As unmanned aerial vehicle (UAV) technology grew in popularity over the years, it was introduced for air quality monitoring. This can easily be used to estimate the sidewalk emission concentration by calculating road traffic emission factors of different vehicle types. These calculations require a simulation of the spread of pollutants from one or more sources given for estimation. For this purpose, a Gaussian plume dispersion model was developed based on the US EPA Motor Vehicle Emissions Simulator (MOVES), which provides an accurate estimate of fuel consumption and pollutant emissions from vehicles under a wide range of user-defined conditions. This paper describes a methodology for estimating emission concentration on the sidewalk emitted by different types of vehicles. This line source considers vehicle parameters, wind speed and direction, and pollutant concentration using a UAV equipped with a monocular camera. All were sampled over an hourly interval. In this article, the YOLOv5 deep learning model is developed, vehicle tracking is used through Deep SORT (Simple Online and Realtime Tracking), vehicle localization using a homography transformation matrix to locate each vehicle and calculate the parameters of speed and acceleration, and ultimately a Gaussian plume dispersion model was developed to estimate the CO, NOx concentrations at a sidewalk point. The results demonstrate that these estimated pollutants values are good to give a fast and reasonable indication for any near road receptor point using a cheap UAV without installing air monitoring stations along the road.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.808-812
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• 2003

디지털 기술의 급속한 발전에 따라 멀티미디어 기술 또한 그 개념이 점점 더 확장되어 가고 있다. 먼저 TV방송에서는 디지털 방송이 시작 되었고 영화 산업 또한 아날로그에서 디지털로 변화하고 있다. 이러한 컴퓨터 그래픽스 관련 멀티미디어 기술의 핵심 중 하나가 영상합성이다. 현재 많은 컴퓨터 그래픽스 기술이 개발되고 있으나 아직까지는 영상 합성 분야의 제작 환경이 고가의 장비와 전문 인력의 부족으로 컴퓨터 보다는 인간의 수작업에 더 많이 의존하고 있는 실정이다. 본 논문에서는 이러한 컴퓨터 그래픽스 분야에서 3D 그래픽스와 디지털 소스의 새로운 영상 합성 방법을 제시했다. 즉, 배경에 사용하게 될 동영상을 Tracking기법으로 평면의 2차원 공간상에서의 물체를 3차원 공간으로 개념을 확장 한 후 이를 다시 3D 그래픽스 저작도구를 사용하여 디지털 소스인 동영상과 3D 모델을 정확하게 3차원 공간상에 일치시킴으로써 보다 쉽고 효율적으로 영상합성을 활용 할 수 있도록 했다.

• 한국지능시스템학회논문지
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• 제21권5호
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• pp.645-652
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• 2011

본 논문은 태양과 반사경의 법선 벡터와 태양의 위치를 일치시키기 위하여 태양 궤적 추적 장치와 반사경의 오차 보정 장치를 설계하여 반사경의 법선 벡터와 태양의 위치를 일치시키도록 시스템을 설계하였다. 이렇게 설계된 시스템은 태양의 빛을 한 점으로 모을 수 있으며, 모여진 태양광을 광섬유를 통하여 원격지로 자연광을 보내어 유용한 광원으로 활용할 수 있다. 그러나 본 논문에서 제안한 이중화된 시스템의 제어기를 설계하기 위해서는 태양 궤적 추적 장치의 2축과 반사경 오차 보정 장치의 2축으로 구성되어 반사경의 법선 벡터에 대한 복잡한 상관관계가 존재하게 된다. 때문에 이러한 복잡한 방정식이 존재하므로 제어기 설계가 매우 복잡하게 된다. 그러나 본 논문에서는 복잡한 수학적 해석을 필요로 하지 않고 인간의 제어 해석 능력을 언어적 기법으로 표현할 수 있는 퍼지제어 기법을 활용하여 태양광을 하나의 정점으로 집광할 수 있는 시스템을 제시하고자 한다.