• 전기의세계
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• v.23 no.6
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• pp.12-15
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• 1974

• 전기의세계
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• v.23 no.5
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• pp.41-44
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• 1974

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.133-142
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• 2005

In this paper, two digital video scrambling methods are proposed as simple means of the digital content protection techniques. One is inter block scrambling using motion vector, the other is intra block scrambling using intra prediction mode. The proposed inter block scrambling method distorts the original sequences by swapping horizontal and vertical components of motion vector. This method can be applied on most common video coding techniques such as MPEG-1, 2, 4, H.264, etc. The proposed intra block scrambling method distorts the original sequences by modifying intra prediction mode that is property of H.254 video coding technique. Both methods do not cause my bit rate increase after scrambling. Moreover, they have low complexity because they need only simple operation like XOR. Especially, the proposed intra block scrambling does not distort inter blocks directly. But inter blocks are distorted by error propagation effect as much as intra blocks. This paper introduces two new digital video scrambling method and verifies its effectiveness through simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.168-172
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• 2009

We compare an integral sliding mode control with a typical sliding mode control for robot manipulators through two primitive tasks: set-point regulation and trajectory tracking control. To prove the asymptotic stability of two methods for robot manipulators, we introduce three important properties in the robot dynamics: skew-symmetry, positive-definiteness, and boundedness of robot parameter matrices and we present one unified control structure using a parametric velocity vector. From illustrative examples, we show that two methods effectively control for robot manipulators.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.151-158
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• 1997

The main concern of numerical dynamic analysis of large structures is to find an acceptable solution with fewer mode shapes and less computational efforts. component mode method utilizes substructure technique to reduce the degrss of freedom but have a disadvantage to not consider the dynamic characteristics of loads. Ritz Vector method consider the load characteristics but requires many integrations and errors are accumulated. In this study, to prove the effectiveness of component mode method, Lanczos algorithm are introduced. To prove the effectiveness of this method, example structures areanalyzed and the results are compared with SAP90.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.142-147
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• 2008

In this paper, we propose a novel a roach to improve the performance of speech/music classification for the selectable mode vocoder (SMV) of 3GPP2 using the support vector machine (SVM). The SVM makes it possible to build on an optimal hyperplane that is separated without the error where the distance between the closest vectors and the hyperplane is maximal. We first present an effective analysis of the features and the classification method adopted in the conventional SMV. And then feature vectors which are a lied to the SVM are selected from relevant parameters of the SMV for the efficient speech/music classification. The performance of the proposed algorithm is evaluated under various conditions and yields better results compared with the conventional scheme of the SMV.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.194-199
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• 2003

The traction drive system for the urban transit Rubber-tire system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the Proposed traction drive system is verified by the MATLAB simulation results.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.579-592
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• 2016

CNUSAIL-1, to be launched into low-earth orbit, is a cubesat-class satellite equipped with a $2m{\times}2m$ solar sail. One of CNUSAIL's missions is to deploy its solar sail system, thereby deorbiting the satellite, at the end of the satellite's life. This paper presents the design results of the attitude control system for CNUSAIL-1, which maintains the normal vector of the sail by a 3-axis active attitude stabilization approach. The normal vector can be aligned in two orientations: i) along the anti-nadir direction, which minimizes the aerodynamic drag during the nadir-pointing mode, or ii) along the satellite velocity vector, which maximizes the drag during the deorbiting mode. The attitude control system also includes a B-dot controller for detumbling and an eigen-axis maneuver algorithm. The actuators for the attitude control are magnetic torquers and reaction wheels. The feasibility and performance of the design are verified in high-fidelity nonlinear simulations.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.807-808
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• 2008

In H.264, sub-pel motion estimation (ME) has strong effect when coding video sequences. 1/4-pel performs better at low bitrate while 1/8-pel gives better results at high bitrate. In this paper, a variable sub-pixel motion vector resolution based on block mode motion estimation method is proposed. Experiment results show that the proposed method can take the advantage of 1/4-pel at low bitrate and 1/8-pel at high bitrate. In addition to that, time is reduced from 14% to 53% compared to KTA1.3 with 1/8-pel motion vector (MV) resolution.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.267-275
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• 2002

The traction drive system for the urban transit maglev system is described in this paper. To control the magnitude and frequency of the output voltage of induction motor transiently, the vector control strategy is generally used. But in case of the traction drive system for the railway vehicle, it is difficult to use the vector control caused by the one-pulse mode in the high speed region. Therefore, this paper proposes the control strategy combined the vector control in the low speed region and the slip frequency control in the high speed region. And also, the overmodulation PWM method is discussed to make the change to the one-pulse mode softly. The performance of the proposed traction drive system is verified by the MATLAB simulation results.