• Journal of Photoscience
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• 제4권2호
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• pp.41-48
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• 1997

The plasma membrane and microsomes, isolated from the cells treated with hematoporphyrm derivative (HpD) for 1 and 24 h, accumulated the aggregated porphyrin. The quantity of aggregated porphyrin was same in the plasma membrane and microsomes after isolating them from cells treated with HpD for 1 h whereas the microsomes accumulated higher quantity of aggregated porphyrin when cells were treated with HpD for 24 h. Photodynamic action of aggregated porphyrin on plasma membrane and microsomes was investigated using lipid specific fluorescent probes: 1,6-diphenyl-1,3,5-hexatrine (DPH) and 1-(4-trimethylammonium), 6-diphenyl-1,3,5-hexatrine(TMA-DPH). The time dependent anisotropy of these probes in the membranes was measured and the decay of anisotropy was analyzed using wobbling in cone model. Upon irradiation both the plasma membrane and the microsomes showed an increase in the limiting anis~)tropy and order parameter and a decrease in the cone angle of the lipid probes. The increase in the limiting anisotropy was pronounced in membranes isolated from the cells treated with HpD for 24 h. Photoinduced change in the limiting anisotropy was dependent on the duration of incubation of cells with HpD before isolating the membranes. In both the membranes. the membrane core was affected more as compared to the outer leaflet. In addition to the structural changes, a decrease in Na$^+$-K$^+$-ATPase and NADPH cyt c reductase activity was also observed upon irradiation of HpD treated cells. Inhibition in NADPH cyt c reductase was more when cells were treated with HpD for 24 h, however, Na$^+$-K$^+$-ATPase activity did not depend on the duration of the treatment of cells with HpD before irradiation. Our results suggest that the extent of photoinduced perturbations in the membranes varies as a function of duration of the treatment of cells with HpD and the membrane core is more susceptible to the photodynamic action of aggregated porphyrin.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.250-253
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• 2009

This paper presents NR (No Reference) Quality assessment method for IPTV or mobile IPTV. Because No Reference quality assessment method does not access the original signal so it is suitable for the real-time streaming service. Our proposed method use decoding parameters, such as quantization parameter, motion vector, and packet loss as a major network parameter. To evaluate performance of the proposed algorithm, we carried out subjective test of video quality with the ITU-T P.910 ACR (Absolute Category Rating) method and obtained the mean opinion score (MOS) value for QVGA 180 video sequence coded by H.264/AVC encoder. Experimental results show the proposed quality metric has a high correlation (84%) to subjective quality.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.795-801
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• 2006

A No Spin Differential (NSD) design has been improved from evaluation of two NSD models utilizing the axiomatic approach. New design parameters of the second level are developed to satisfy the independence axiom. The design matrices are determined to decouple the relationship between design parameters and process parameters. The values of process parameters are then determined to optimize and improve the NSD design. Consequently a unique and evolutionary NSD design is achieved with the aid of the axiomatic approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 A
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• pp.480-483
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• 1992

Although the back-propagation(BP) algorithm is widely used for its simple structure and easy learning method, it has a drawback of slow convergence rate. In this paper, we propose an algorithm to improve this problem by manipulating the slope parameter of the activation function. The steepest descent method is used in learning the slope parameter, as in the case of weight. The simulation shows that the learning rates of the proposed algorithm is faster than the conventional BP algorithm.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
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• pp.47-48
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• 2005

This paper describes how an Artificial Neural Network(ANN) can be employed to improve a speed estimation in a vector controlled induction motor drive. The system uses the ANN to estimate changes in the motor resistance, which enable the sensorless speed control method to work more accurately. Flux Observer is used for speed estimation in this system. Obviously the accuracy of the speed control of motor is dependent upon how well the parameters of the induction machine are known. These parameters vary with the operating conditions of the motor; both stator resistance(Rs) and rotor resistance(Rr) change with temperature, while the stator leakage inductance varies with load. This paper proposes a parameter compensation technique using artificial neural network for accurate speed estimation of induction motor and simulation results confirm the validity of the proposed scheme.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.637-638
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• 2006

V-belt pulleys play a key role in driving cooling pump, oil pump, air-conditioner and so on by using an engine power. Precision deep drawing is one of the main processes for manufacturing the pulleys. Operation variables of the deep drawing equipment, called the setup parameter, must be re-determined whenever the specifications of pulley to be produced are changed. The defect rates during a setup of equipment and the working hours needed for the setup are almost dependent on workers' know-how. This study designs the program for easily determining setup conditions in pulley manufacturing process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.359-360
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• 2006

Recently, a lot of work and interest has been devoted to the development of multiaxial fatigue parameters for fretting fatigue life prediction. Many of these parameters have been reviewed in the literature for simple geometries like a cylinder-on-flat contact configuration. The purpose of this study was to estimate fretting fatigue life using critical plane approach which is one of the multiaxial fatigue theories.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1692-1695
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• 1997

This paper describes the relationship between the various non-destructive parameters and the breakdown voltage for the 17 kV, 300 MVA and the 22 kV, 500 MVA generators stator bars with polyester and epoxy/mica insulation respectively. Also, this study reports the results of an investigation into the factors which can assess the insulation condition of generator stator winding. Furthermore, a new parameter, Partial Discharge Index(PDI), is introduced as the valuable parameter for the assessment of insulation condition. The ratio between partial discharge increment and the stepwise voltage increment from the Discharge Inception Voltage (DIV) at the characteristic or resonant frequency band shows the close relationship between the breakdown voltage and PDI.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.12-14
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• 1998

Sensorless PMSM is much studied for the industrial applications and home appliances because a mechanical sensor reduces reliability and increases cost. This paper studies the stability of sensorless speed control of PMSM using state observer. Sensorless control scheme using state observer is known as a scheme having a comparatively good performance. Several papers have studied the stability of state observer control scheme, but have not considered parameter variation which is important to sensorless control. This paper studies the stability through computer simulation in case of parameter variation.

• 한국통신학회논문지
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• 제32권6C호
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• pp.579-584
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• 2007

최근 다시점 비디오를 효율적으로 부호화하기 위해 다양한 시공간 예측 구조들이 제안되었다. 이 논문에서는 다시점 비디오 부호화 예측 구조에서 각 GOP의 첫 화면들에 삽입되는 B$_{ANC}$ 화면을 위해 양자화 계수를 결정하는 방법을 제안한다. 각 시점의 영상 화질을 균일하게 유지하고 전체적인 부호화 효율을 높이기 위해 B$_{ANC}$ 화면의 양자화 계수를 적응적으로 조절하며, 인접한 두 참조화면의 비트-왜곡 비용값을 사용하여 상관도를 추정하고 이를 이용하여 B$_{ANC}$ 화면의 양자화 계수를 결정한다. 이 논문에서 제안한 방법을 다시점 비디오 참조 예측 구조에 적용하여 부호화한 결과, 0.09$\sim$0.16 dB 정도의 PSNR 개선을 얻었다.