• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.4
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• pp.305-312
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• 2015

In this study, inter-turn short fault models of interior permanent magnet synchronous motors (IPMSM) are developed by adding saliency modeling to surface-mounted permanent magnet motor models. The saliency model is obtained using the deformed flux models based on both fault-winding flux information and inductance variations caused by cross-flux linkages that depend on the distribution of the same phase windings. By assuming the balanced three-phase current injection, we obtain the positive and negative sequence voltages and the fault current in the positive and the negative synchronous reference frames. The output torque model is developed by adding the magnet and the reluctance torque, which are derived from the developed models. To verify the proposed IPMSM model with an inter-turn short fault, finite element method-based simulation and experimental measurement results are presented.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2011-2016
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• 2004

In order to develop a high efficiency fire pump, its performance characteristics with various operating conditions are investigated. The governing equations are derived from making using of three-dimensional Navier-Stokes equations with the standard ${\kappa}-{\varepsilon}$ turbulence model and SIMPLE algorithm. Using a commercial code, CFX, pressure distribution and flow fields in a fire pump are calculated with various ranges of rotating speed 800-2400 rpm. Particularly, calculations with multiple frames of reference method between the rotating and stationary parts of the domain are carried out. With the help of numerical results, correlation formula between the casing pressure and the efficiency is derived.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.127-130
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• 2007

The increased availability of portable, low-cost, high resolution video devices has resulted in a rapid growth of the applications for video sequences. These video devices can be mounted in handhold unit, mobile unit and airborne platforms like maned or unmaned helicopter, plane, airship, etc. A core technique in use of video sequences is to align neighborhood video frames to each other or to reference images. For video sequences registration, we extracted interested points from aerial video sequences using Harris, $F{\square}rstner$, and KLT operators and implemented image matching using these points. As the result, we analysed image matching results for each operators and evaluated accuracy of aerial video registration.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.77-80
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• 2000

In this paper, the speaker-recognition process based on both DTW and discrete HMM was performed using the method to evaluate state-dependent parameter weighting from training data so as the personal audio-characteristics are to be well reflected. In the suggested method below, we found the optimal state sequence using the Viterbi algorithm. The optimal path could be evaluated after comparing the sequence of base pattern which already have, with that of the other patterns. After that the frame of which the pattern was matched with the base pattern in the same state are to be found so that the reference pattern can be gained by weighting on the numbers of matched frames.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.93-101
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• 2017

This paper proposes an algorithm for adaptive loop filter (ALF) complexity reduction in the decoding process. In the original ALF algorithm, filtering for I frames is performed in the frame unit, and thus, all of the pixels in a frame are filtered if the current frame is an I frame. The proposed algorithm is designed on top of the local gradient calculation. On both the encoder side and the decoder side, homogeneous areas are checked and skipped in the filtering process, and the filter coefficient calculation is only performed in the inhomogeneous areas. The proposed algorithm is implemented in Joint Exploration Model (JEM) version 3.0 future video coding reference software. The proposed algorithm is applied for frame-level filtering and intra configuration. Compared with the JEM 3.0 anchor, the proposed algorithm has 0.31%, 0.76% and 0.73% bit rate loss for luma (Y) and chroma (U and V), respectively, with about an 8% decrease in decoding time.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.285-286
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• 2006

H.264 provide good coding efficiency compared with existing video coding standards as H.263, MPEG-4, etc. However, H.264 require the increase of encoder complexity. In this paper, fast mode decision algorithm by skipping variable block size motion estimation and spatial-predictive coding, which occupies most encoder complexity, is proposed. Experimental results show that the proposed approach can save encoding time to 55% compared with the H.264 standard.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.9-13
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• 2006

In the present study, a numerical analysis of transient mixer flow is performed considering free surface formation. The flow patterns and free surface shape in a mixers formed by flat paddle and pitched paddle impellers are predicted. In a flat paddle mixer, two flow circulation regions are formed due to strong radial flow, whereas one large circulation is formed in a pitched paddle mixer due to axial downward flow. These differences affect the free surface evolution and shape. It is seen from the results that a flat paddle mixer gives deeper free surface at center region than a pitched paddle mixer. The free surface of 8-blades-flat-paddle mixer is also simulated to compare with the available experimental and simulation results. The present computational results agree reasonably well with the experimental data.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.288-291
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• 2011

Video stabilization is an important image enhancement widely used in surveillance system in order to improve recognition performance. Most previous methods calculate inter-frame homography to estimate global motion. These methods are relatively slow and suffer from significant depth variations or multiple moving object. In this paper, we propose a fast and practical approach for video stabilization that selects the most reliable key frame as a reference frame to a current frame. We use optical flow to estimate global motion within an adaptively selected region of interest in static camera environment. Optimal global motion is found by probabilistic voting in the space of optical flow. Experiments show that our method can perform real-time video stabilization validated by stabilized images and remarkable reduction of mean color difference between stabilized frames.

• ETRI Journal
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• v.38 no.6
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• pp.1095-1103
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• 2016

We present a method for transferring deformation weights of a human character to three-dimensional (3D) scanned clothes. First, clothing vertices are projected onto a character skin. Their deformation weights are determined from the barycentric coordinates of the projection points. For more complicated parts, such as shoulders and armpits, continuously moving planes are constructed and employed as projection reference planes. Clothing vertices on a plane are projected onto the intersection curve of the plane with a character skin to achieve a smooth weight transfer. The proposed method produces an initial deformation for physically based clothing simulations. We demonstrated the effectiveness of our method through several deformation results for 3D scanned clothes.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.13-20
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• 2005

This paper has proposed an algorithm for the initial pole position estimation of a permanent magnet linear synchronous motor(PMLSM). The algorithm finds the initial pole position observing the maximum values of a position generated by the new proposed two reference frames for the same force input. So, the proposed algorithm does not utilize the motor parameters and is insensitive to them. Moreover, the proposed algorithm is easily realized because the proposed method is just using PI controller