• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.201-207
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• 2020

With the expansion in the use of DC power systems and increased need for system maintenance, the development of measurement devices for maintenance requires high stability. Of the different kinds of DC current measurement devices, the single-shot measurement device causes the input signal of the current measuring unit to initially generate a high inrush current. The high inrush current flows into the signal processor of the meter, shortening the life of the internal fuses and causing failure. Therefore, in this study, the I²t value for increasing the durability of the fuse is designed using the available wire diameter. Operating characteristics for 210~400% over-current of the rated current, which is relatively low over-current, are realized by the plating of low melting tin metal. As a result, a method of designing a fuse element for a DC power supply, which improves the safety of the DC current measurement device by blocking the failure caused by the inrush current, is presented.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.385-394
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• 2002

Satellite laser ranging is a technique for precisely measuring the range between a laser station and a satellite that is equipped with retro-reflectors. SLR technique was first used for Beacon-B satellite in 1964 with the ranging accuracy of meter level. Now the single shot have centimeter level accuracy and the normal point have mm level in ranging. In this study we developed the algorithm for precise orbit determination using SLR data and performed the orbit determination of GPS-36 satellite using the algorithm. RMS of the estimated orbit was 74cm when compared with IGS precise orbit. It is known that RMS of SLR measurement residual is below 55mm. But we were able to achieve 44mm RMS of residual throughout this study.

• Journal of Broadcast Engineering
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• v.24 no.4
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• pp.573-579
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• 2019

To achieve fully autonomous driving, the perceptual skills of the surrounding environment must be superior to those of humans. The $60^{\circ}$ angle, $120^{\circ}$ wide angle cameras, which are used primarily in autonomous driving, have their disadvantages depending on the viewing angle. This paper uses a multi-angle object recognition system to overcome each of the disadvantages of wide and narrow-angle cameras. Also, the aspect ratio of data acquired with wide and narrow-angle cameras was analyzed to modify the SSD(Single Shot Detector) algorithm, and the acquired data was learned to achieve higher performance than when using only monocular cameras.

• Smart Structures and Systems
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• v.23 no.4
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• pp.359-371
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• 2019

As part of a structural health monitoring system, the relative geometric relationship between a ship and bridge has been recognized as important for bridge authorities and ship owners to avoid ship-bridge collision. This study proposes a novel computer vision method for the real-time geometric parameter identification of moving ships based on a single shot multibox detector (SSD) by using transfer learning techniques and monocular vision. The identification framework consists of ship detection (coarse scale) and geometric parameter calculation (fine scale) modules. For the ship detection, the SSD, which is a deep learning algorithm, was employed and fine-tuned by ship image samples downloaded from the Internet to obtain the rectangle regions of interest in the coarse scale. Subsequently, for the geometric parameter calculation, an accurate ship contour is created using morphological operations within the saturation channel in hue, saturation, and value color space. Furthermore, a local coordinate system was constructed using projective geometry transformation to calculate the geometric parameters of ships, such as width, length, height, localization, and velocity. The application of the proposed method to in situ video images, obtained from cameras set on the girder of the Wuhan Yangtze River Bridge above the shipping channel, confirmed the efficiency, accuracy, and effectiveness of the proposed method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.35-36
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• 2019

Major influence factors for piercing depth of concrete against small caliber bullet are target's property such as compression strength of concrete and bullet's property such as the velocity and weight of it. In particular about the bullet's property, velocity and incidence angle could be controlled by specific position or distance between targets and shooter, but the angle of yaw of bullet dose not. Because the the angle of yaw of bullet causes lower piercing force of bullet, some errors on piercing depth of concrete could be appeared by live fire test for the evaluation of protective performance. Therefore, we have checked the error canceling effect on the piercing depth of concrete by single shot and barrage of small caiber bullets. As a result, we identified that the error of piercing depth by the angle of yaw of bullet could be cancelled by barrage.

• Journal of KIISE:Software and Applications
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• v.36 no.2
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• pp.169-177
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• 2009

In this paper, we propose a new shot boundary detection method which is optimized for news video story parsing. This new news shot boundary detection method was designed to satisfy all the following requirements: 1) minimizing the incorrect data in data set for anchor shot detection by improving the recall ratio 2) detecting abrupt cuts and gradual transitions with one single algorithm so as to divide news video into shots with one scan of data set; 3) classifying shots into static or dynamic, therefore, reducing the search space for the subsequent stage of anchor shot detection. The proposed method, based on singular value decomposition with incremental clustering and mercer kernel, has additional desirable features. Applying singular value decomposition, the noise or trivial variations in the video sequence are removed. Therefore, the separability is improved. Mercer kernel improves the possibility of detection of shots which is not separable in input space by mapping data to high dimensional feature space. The experimental results illustrated the superiority of the proposed method with respect to recall criteria and search space reduction for anchor shot detection.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.427-439
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• 2008

This paper proposes a novel method to convert monoscopic soccer videos to stereoscopic videos. Through the soccer video analysis process, we detect shot boundaries and classify soccer frames into long shot or non-long shot. In the long shot case, the depth mapis generated relying on the size of the extracted ground region. For the non-long shot case, the shot is further partitioned into three types by considering the number of ground blocks and skin blocks which is obtained by a simple skin-color detection method. Then three different depth assignment methods are applied to each non-long shot types: 1) Depth estimation by object region extraction, 2) Foreground estimation by using the skin block and depth value computation by Gaussian function, and 3)the depth map generation for shots not containing the skin blocks. This depth assignment is followed by stereoscopic image generation. Subjective evaluation comparing generated depth maps and corresponding stereoscopic images indicate that the proposed algorithm can yield the sense of depth from a single view images.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.54.2-54.2
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• 2019

Removing noise which occurs inevitably when taking image data has been a big concern. There is a way to raise signal-to-noise ratio and it is regarded as the only way, image stacking. Image stacking is averaging or just adding all pixel values of multiple pictures taken of a specific area. Its performance and reliability are unquestioned, but its weaknesses are also evident. Object with fast proper motion can be vanished, and most of all, it takes too long time. So if we can handle single shot image well and achieve similar performance, we can overcome those weaknesses. Recent developments in deep learning have enabled things that were not possible with former algorithm-based programming. One of the things is generating data with more information from data with less information. As a part of that, we reproduced stacked image from single shot image using a kind of deep learning, conditional generative adversarial network (cGAN). r-band camcol2 south data were used from SDSS Stripe 82 data. From all fields, image data which is stacked with only 22 individual images and, as a pair of stacked image, single pass data which were included in all stacked image were used. All used fields are cut in $128{\times}128$ pixel size, so total number of image is 17930. 14234 pairs of all images were used for training cGAN and 3696 pairs were used for verify the result. As a result, RMS error of pixel values between generated data from the best condition and target data were $7.67{\times}10^{-4}$ compared to original input data, $1.24{\times}10^{-3}$. We also applied to a few test galaxy images and generated images were similar to stacked images qualitatively compared to other de-noising methods. In addition, with photometry, The number count of stacked-cGAN matched sources is larger than that of single pass-stacked one, especially for fainter objects. Also, magnitude completeness became better in fainter objects. With this work, it is possible to observe reliably 1 magnitude fainter object.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.172-177
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• 1996

We have characterized XeCl excimer-laser-induced crystallization of thin amorphous silicon films deposited by PECVD (${\alpha}$-Si:H) and LPCVD (${\alpha}$-Si). The electrical properties, surface roughness and crystallinity of crystallized thin films have been measured. The dc conductivities, crystallinity andsurface roughness of the films increased as the laser energy density and shot density were increased. The properties of laser annealed films deposited by LPCVD were better than those of thin films deposite by PECVD. We have also found that the multiple shots with relative low energy density were more benifical to the improsvement of surface roughness than the single shot with high energy density preserving the crystallinity.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.11a
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• pp.120-124
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• 2001

A new technique for improving the efficiency of single-phase high-frequency boost converter is proposed. This converter includes an additional low-frequency boost converter which is connected to the main high-frequency switching device in parallel. The additional converter is controlled at lower frequency. Most of the current flows in the low-frequency switch and so, high-frequency switching loss is greatly reduced accordingly Both switching device are controlled by a simple method; each controller consists of a one-shot multivibrator, a comparator and an AND gate. The converter works cooperatively in high efficiency and acts as if it were a conventional high-frequency boost converter with one switching device. The proposed method is verified by simulation. This paper describes the converter configuration and design, and discusses the steady-state performance concerning the switching loss reduction and efficiency improvement.