• 한국통신학회논문지
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• 제17권3호
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• pp.297-306
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• 1992

G3 FAX용 1칩 이진 영상 처리기구현을 위하여 알고리즘들을 개발하였다. CCD또는 CIS로 부터의 ANALOG 신호를 DIGITIZING한 후, SHADING 및 GAMMA 보정 등의 전처리된 DATA의 화질 개선을 위하여 본 논문에서는 개선된 고화질 문서 이진화 알고리즘을 제안하고, 고화질 중간조를 위한 오차 확산 알고리즘 들을 분석하였으며, 혼재 모드 영상처리를 위해 퍼지 이론에 근거한 알고리즘을 새로이 제안하였다.

• 한국CDE학회논문집
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• 제12권2호
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• pp.109-117
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• 2007

Three-dimensional mesh models have been widely used in various applications such as simulations, animations, and e-catalogs. In such applications the normal vectors of mesh models are used mainly for shading and take up the major portion of data size and transmission time paper over networks. Therefore a variety of techniques have been developed to compress them efficiently. In this paper, we propose the MOEC (Modified Octree Encoding Compression) algorithm, which allow multi lever compression ratios for 3D mesh models. In the algorithm, a modified octree has nodes representing their own positions and supporting a depth of the tree so that the normal vectors are compressed up to levels where the shading is visually indistinguishable. This approach provides efficient in compressing normals with multi-level ratios, without additional encoding when changing in compression ratio is required.

• KIEAE Journal
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• 제14권4호
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• pp.35-45
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• 2014

The main objective of this study is to provide an effective algorithm of the transmitted solar radiation calculation through window glazing on a clear day. This algorithm would be used in developing a computer program for fenestration system analysis and shading device design. Various simulation methods have been evaluated to figure out the most accurate and effective procedure in estimation of transmitted solar radiation on a tilted surface on a clear day. Characteristics of simulated results of each step have been scrutinized by comparing them with measured results of the site as well as results from other simulation programs. Generally, the Duffie & Beckman's solar calculation method introducing the HDKR anisotropic model provided the most reliable simulation results. The DOE-2 program usually provided over-estimated simulation results. The estimation of extraterrestrial solar radiation and beam normal radiation were conducted pretty accurately. However, the solar radiation either on horizontal surface or on tilted surface involves complicated factors in estimation. Even though the estimation results were close to the real measured data during summer when solar intensity is getting higher, the estimation provided more error when solar intensities were getting weaker. The convex polygon clipping algorithm with homogeneous coordinates was fastest model in calculation of sunlight to shaded area ratio. It could not be applied because of its shape limitation.

• 대한전자공학회논문지SD
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• 제46권10호
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• pp.46-52
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• 2009

현재 개발되고 있는 Shader 프로세서는 처리 성능을 높이기 위하여 Multi-Core, Multi-Thread를 채택하고 있다. 또한 Shader 프로세서에서 각 수행 단계별 마다 IP를 따로 구현하지 않고 하나의 Core IP를 다양한 목적으로 사용할 수 있도록 설계하고 있다. 본 논문에서는 이러한 목적에 맞게 Shader-Core를 이용하여 연산이 가능하고, Multi-Core, Multi-Thread 기반에서 픽셀의 병렬처리가 가능하도록 고안된 Vector 기반의 Rasterization알고리즘을 제안한다. 이를 통하여 동일 조건의 기존 알고리즘에 비하여 약 2%의 연산량을 가지면서 각 픽셀이 독립적으로 연산이 가능하도록 하였다.

• 한국태양에너지학회 논문집
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• 제36권5호
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• pp.91-100
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• 2016

This paper proposes the PV module fault diagnosis sensor which is applied to Zigbee wireless network, and monitoring system using the developed sensor. It is designed with embedded sensor in junction box. The diagnosis elements for algorithm were voltage and temperature. For that reason, It is able to reduce the price and separate the fault of bypass diode from shading differently from other monitoring systems. This fault diagnosis algorithm verified through the Field-installed operations of PV module.

• Journal of Power Electronics
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• 제19권5호
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• pp.1259-1269
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• 2019

PV system performance is dependent on different irradiations and temperature values in addition to the capability of the employed PV inverter / maximum power point tracker (MPPT) circuit or algorithm. Therefore, it would be appropriate to use a PV simulator capable of producing identical repeatable conditions regardless of the weather to evaluate the performance of inverter / MPPT circuits and algorithms. In accordance with this purpose, a photovoltaic (PV) array simulator is presented in this paper. The simulator is designed to generate current-voltage (I-V) and power-voltage (P-V) curves of a PV panel. Series connected cascaded modules constitute the basic part of the simulator. This feature also allows for the modeling of PV arrays since the number of modules can be increased and high voltage values can be reached with the simulator. In addition, the curves obtained at the simulator output become similar to the actual curves of sample PV panels with an increase in the number of modules. In order to show the validity of the proposed simulator, it was simulated for various situations such as panels under full irradiance and partial shading conditions. After completing simulations, experiments were realized to support the simulation study. Both simulation and experimental results show that the proposed simulator will be very useful for researchers to carry out PV studies under laboratory conditions.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 1998년도 가을 학술발표논문집 Vol.25 No.2 (2)
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• pp.476-478
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• 1998

본 논문에서는 영상의 밝기 정보로부터 물체의 표면 형상을 재구성하는 새로운 접근 방법을 제시한다. 이미지 모델은 기존의 Lambertian surface model에 거리 요소를 포함시켜 보다 현실과 비슷한 제약 조건을 주고, 국지 해(local minima)에 빠지기 쉬운 기존의 iteration 방법을 탈피하기 위해 유전자 알고리즘(genetic algorithm)을 도입한다. 표면의 깊이 정보를 이산여현변환(discrete cosine transform)하고 이 DCT 공간상에서 유전자 알고리즘을 적용함으로써 큰 형상을 먼저 결정한 후 미세한 형상을 찾아내는 계층적인 표면 형상의 재구성이 가능하도록 하였으며 간단한 실험으로 그 타당성을 보인다.

• 제어로봇시스템학회논문지
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• 제7권12호
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• pp.1015-1023
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• 2001

error behaviour can be considered as a linear combination of low amplitude random noise and abrupt jumps. The reason of jump appearance can be explained by the semi-shading effects(buildings, trees), jamming, high dynamic of vehicle and so on. This study describes the stand-alone GPS error jump smoothing algorithm which is developed based on the scalar adaptive filter. The algorithm consists of the coarse jump smoothing and the fine jump smoothing. On the coarse smoothing step, GPS velocities or position differences are used as the measurement for the scalar adaptive filter. The purpose of adaptive filter is to smooth the jump errors. The coarse positions are detennined by the integration of smoothed velocities. On the fine smoothing step, the differences between GPS positions and the coarse positions are smoothed by another scalar adaptive filter. The reason of fine smoothing is based on the facts that smoothing accuracy depends on the variance ofusefuJ signa\. The coarse smoothing which deal with the difference of positions provides the rough error removing. So the coarse smoothed velocities can have much more low amplitude than the raw ones. The fine smoothing procedure provides high quality of filtering process. Simulation results show the efficiency of proposed scheme.

• Advances in Energy Research
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• 제1권2호
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• pp.97-106
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• 2013

This study designs and tests a photovoltaic system with distributed maximum power point tracking (DMPPT) methodology using a field programmable gate array (FPGA) controller. Each solar panel in the distributed PV system is equipped with a newly designed DC/DC converter and the panel's voltage output is regulated by a FPGA controller using PI control. Power from each solar panel on the system is optimized by another controller where the quadratic maximization MPPT algorithm is used to ensure the panel's output power is always maximized. Experiments are carried out at atmospheric insolation with partial shading conditions using 4 amorphous silicon thin film solar panels of 2 different grades fabricated by Chi-Mei Energy. It is found that distributed MPPT requires only 100ms to find the maximum power point of the system. Compared with the traditional centralized PV (CPV) system, the distributed PV (DPV) system harvests more than 4% of solar energy in atmospheric weather condition, and 22% in average under 19% partial shading of one solar panel in the system. Test results for a 1.84 kW rated system composed by 8 poly-Si PV panels using another DC/DC converter design also confirm that the proposed system can be easily implemented into a larger PV power system. Additionally, the use of NI sbRIO-9642 FPGA-based controller is capable of controlling over 16 sets of PV modules, and a number of controllers can cooperate via the network if needed.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2011년도 추계학술대회
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• pp.49-52
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• 2011

본 논문에서는 구간선형 모델을 적용하여 낮은 복잡도를 가지는 LSC(Lens-Shading Correction) 알고리즘을 제안한다. 제안한 알고리즘은 각 화소와 렌즈 중심점으로부터 거리를 정수형으로 계산하고, 이 정수를 거리에 대한 LSC 이득값이 저장된 LUT(Look-Up Table)에 대한 주소로 적용하여, 입력 화소 값에 곱함으로써 LSC를 수행한다. 거리를 구하려면 제곱근 회로가 추가되어야 한다. LUT에 저장된 이득값은 원점으로부터의 거리에 대한 평균 이득값을 저장하고 있기 때문에, 제곱근 계산에 높은 정밀도를 할애하여도 LSC 보상된 영상의 화질에 미치는 영향은 높지 않으므로 정수형 제곱근 연산을 수행한다. 제곱근 계산은 구간 선형화하여 단지 덧셈과 쉬프트 연산만으로 제곱근 연산을 완료할 수 있도록 간략화 하였다. 제안한 알고리즘을 양산 중인 일반 카메라 모듈에 적용한 결과, 카메라모듈 제조업체의 LSC 평가 기준을 상회하는 수준으로 나타나며, 구현될 하드웨어 복잡도가 매우 낮아서 모바일 카메라 구현에 매우 적합하다.