• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2019년도 추계학술대회
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• pp.20-21
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• 2019

The Joint Video Experts Team (JVET) has been working on the development of next generation of video coding standard called Versatile Video Coding (VVC). Position Dependent Intra Prediction Combination (PDPC) which is one of the major tools for intra prediction refines the prediction through a linear combination between the reconstructed samples and the predicted samples according to the sample position. In VVC WD6, nScale which is shift value that adjusts the weight is determined by the width and height of the current block. It may cause that PDPC is applied to regions that do not fit the characteristics of the current intra prediction mode. In this paper, we define nScale for each width and height so that the weight can be applied independently to the left and top reference samples, respectively. Experimental results show that, compared to VTM 6.0, the proposed method gives -0.01%, -0.04% and 0.01% Bjotegaard-Delta (BD)-rate performance, for Y, Cb, and Cr components, respectively, in All-Intra (AI) configuration.

• 전기의세계
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• 제28권2호
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• pp.68-75
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• 1979

The penetration of an electro-magnetic wave through an aperture in a cylindrical structure with a center dielectric-rod is investgated. By using a standard mode matching procedure, the electrical and magnetic fields in a cavity are determined as a function of position inside the cavity and frequency of the incident field. For the given parameters, computed data are obtained and the results exhibited in form of amplitude curves of the nor malized field and energy densities of functions of position and frequency. Depending on the increase of the relative dielectric constant of center dielectric-rod, the resonance frequecies of the cavity vary as the cavity size decrease. The stored electro-magnetic energy varies very rapidly as a function of position inside the cavity and of the source frequency. Its peak value can be two orders of magnitude greater than the incident energy density. The frequencies where the peaks occur can be identified approximately as the resonance frequencies of the cavity.

• 대한기계학회논문집A
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• 제26권2호
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• pp.254-259
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• 2002

A variable air-gap type system is widely used for inductive precision position measurement systems. This type transducer has high sensitivity but lacks a linear measurement range due to structural nonlinearity. Furthermore, as measurement range increases, linearity error is also increased. The alternative is a variable overlap-area type system. The sensitivity of this type is determined by the initial air-gap dimension, keeps the original value and does not deteriorate linearity in spite of the variations of the measuring range.

• 한국정밀공학회지
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• 제18권4호
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• pp.190-196
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• 2001

The naval vessel must moves rolling, pitching, yawing by wave when it runs in ocean. Some narrow beam antenna needed position compensation by stabilizer or gimbal for best performance. This paper presents the precision position control for heavy weight(130kg) in roll and pitch direction. Generally it's called for gimbal. This gimbal uses P-I controller, and it's driven by linear actuator and servo motor. This gimbal gets ship's gyro signal and synchro, which have the absolute angle value. Some other similar equipments are driven by huge hydraulic power, but this gimbal is driven by small servo motor. This control loop gets the following procedure repeatedly; reading ship gyro and gimbal synchro, calculating compensated error and control output, driving motor and actuator The performance of gimbal system was satisfied.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제12B권1호
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• pp.31-36
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• 2002

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position; therefore, the position of rotor is an essential information. Although optical encoders or resolvers are used to provide the position information, these sensors are expensive. Moreover, in the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost analog encoder suitable for practical applications is proposed. And the control algorithm to generate switching signals using a simple digital logic is presented. The validity of the proposed analog encoder with a proper logic controller is verified from the experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.219-224
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• 2001

An accurate tip position control of a single-link flexible manipulator subjected to torque disturbance is achieved by utilizing so called sliding mode controller with disturbance estimation (SMCDE). After formulating the governing equation of motion in the state 1pace representation, a stable sliding surface is designed via the LQR method. The SMCDE is then synthesized by integrating equivalent sliding mode controller with the disturbance estimator which is featured by an integrated average value of the imposed disturbance over a certain sampling period. The regulating tip motion of the flexible manipulator is evaluated by employing the proposed SMCDE.

• Journal of the Korean Data and Information Science Society
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• 제15권4호
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• pp.855-866
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• 2004

In many surveys, one of the most important goals is to obtain reliable and valid responses from respondents. To achieve the goal, a researcher have to make efforts to protect respondents' confidentiality and to reduce the effects of social desirability on answers. The key question of this paper is whether the position of demographic questions have an effect on responses. Two types of questionnaires are considered: one puts the demographic questions at the beginning and the other does at the last. On both types, I asked only a small number of demographic questions which are considered as essential on analytic purposes. The results show no evidence of position effects when the risk to threat confidentiality was minimized.

• 한국IT서비스학회지
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• 제6권3호
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• pp.225-239
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• 2007

Mobile service is highly becoming in the limelight on information society by offering infringement problem about individual privacy or information by political and scientific interest This study is focusing on primary LBS application Mobile service that emphasize position confirmation, especially, looking for friends. The aim at this study grasps user productivity factor of LBS application Mobile service, and analyses whether some have relations with value and action determination of LBS application Mobile service. According to result, Mobile service applying position service is supported with usefulness and system quality, adaptedness. On the other hand, Usability and social effect, privacy weren't embossed by leading person. Mobile service applying position service is changed with a person who have experience looking for friend. This study has systematically analysed about LBS application service by leading person

• International Journal of Precision Engineering and Manufacturing
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• 제5권4호
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• pp.14-20
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• 2004

In this work, a new control methodology to achieve accurate position control of an AC servo motor subjected to external disturbance is proposed. Unlike conventional sliding mode controller which requires a prior knowledge of the upper bound of external disturbance, the proposed technique, called sliding mode controller with disturbance estimator (SMCDE), can offer robust control performances without a prior knowledge of the disturbance bound. The SMCDE is featured by an integrated average value of the imposed disturbance over a certain sampling period. By doing this, undesirable chattering phenomenon in the estimation process can be effectively alleviated. The benefits of the proposed control methodology are empirically demonstrated on AC servo motor and control responses are evaluated through a comparative work between the proposed and conventional control schemes.

• 한국생산제조학회지
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• 제20권2호
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• pp.139-144
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• 2011

This paper presents a boundary element application to determine the optimal impressed current densities at defect position on the pipe line. In this protection paint, enough current must be impressed to lower the potential distribution on the metal surface to the critical values. The optimal impressed current densities are determined in order to minimize the power supply for protection. This inverse problem was formulated by employing the boundary element method. Since the system of linear equations obtained was ill-conditioned, including singular value decomposition, conjugate gradient method were applied and the accuracies of these estimation. Several numerical examples are presented to demonstrate the practical applicability of the proposed method.