• Journal of Broadcast Engineering
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• v.22 no.6
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• pp.808-816
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• 2017

360 VR video systems has become important to provide immersive effect for viewers. The system consists of stitching, projection, compression, inverse projection, viewport extraction. In this paper, an efficient luminance compensation technique for 360 VR video sequences, where feature extraction and histogram equalization algorithms are utilized. The proposed luminance compensation algorithm enhance the performance of stitching in 360 VR system. The simulation results showed that the proposed technique is useful to increase the quality of the displayed image.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.4
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• pp.8-14
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• 2004

In this paper, We designed the electronic ballast power factor corrected(PFC) circuity for an 400[W] hight pressure soldium lamp using boost-converter. The values of PFC elements in the proposed boost-converter circuit are calculated theoretically and performed simulation using IsSPICE. We also implemented the ballast for high pressure sodium lamp and experiments. We found that the experimental characteristics of implemented PFC circuit were same with those of simulation results. The experimental results show the performance as PF 90.3[%] at output 400(W).

• 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.153-158
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• 2005

In this paper, a filter is proposed to compensate droop of the CIC filter for SDR. The proposed compensation filter has almost linear-phase characteristic, requires low operational complexity, and is cost-effective due to its second-order characteristic and lowest operational rate in the baseband.. Especially, it compensates droop in the passband with little performance degradation in the stopband. It is shown, by a design example and its performance analysis, that the proposed compensation method gives performance enhancement in communication systems. It is also shown that the proposed method is superior to conventional ones in view of memory usage and computational load.

• Korean Journal of Optics and Photonics
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• v.18 no.3
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• pp.208-215
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• 2007

A fiber-coupled laser-diode pumped ceramic Nd:YAG laser for compensating the thermal tensing effect was developed. The thermal tensing effect was compensated using a convex lens, which was 25 mm away from the laser rod, with a focal length of 30 mm and an effective clear aperture of 22 mm. Without a compensator, the laser output power decreased suddenly above a pump power of 6 W. Using a compensator, the laser output power increased linearly according to the pump power. The beam propagation factor $M^{2}$ was 2.4 under a pump power of 12 W.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.76-79
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• 2010

본 논문에서는 고 효율 및 고 출력 특성을 가지는 질화갈륨(GaN) 소자를 이용하여 WiMAX 및 LTE System에 사용될 수 있는 DPD용 Pallet Amplifier를 제작하였다. 제작된 Pallet Amplifier는 Pre-drive로써 저 전류의 MMIC를 채택하고, Drive 단과 Main 단에 15W 급과 30W 급의 질화갈륨 소자를 사용 하였으며, 추가적인 효율 개선을 위해 PCB상에 Doherty Structure를 적용함으로써 보다 높은 효율을 구현하였다. 제작된 Pallet Amplifier는 음 전원 Bias 제어 회로, 온도에 따른 Gain 보상회로, Sequence 회로 및 Main 전원 Drop에 따른 보호 회로를 구현하였다. WiMAX Signal을 이용한 Modulation Power 10Watt Test에서 약 36.8~38.3%의 Pallet 효율과 DPD Solution인 TI GC5325SEK DPD Board 사용 시 ACLR은 약 46dBc 이상을 가지는 것으로 측정되었다. 본 논문에서 제작된 Pallet Amplifier는 Upper Band와 Lower Band로 나누어 제작되었던 기존 Pallet Amplifier와 달리 하나의 Pallet Amplifier로 2496~2690MHz에서 모두 사용하면서 종전에 사용되고 있는 Pallet Amplifier에 비해 Size가 최소 10% 이상 축소되어 효율 및 크기 면에서 종전 Pallet Amplifier보다 큰 이점을 갖는다.

• Convergence Security Journal
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• v.16 no.1
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• pp.23-32
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• 2016

The more a society becomes complicated and diversified along with the economic development, the more diverse l earning types the educational activities had beyond the existing educational approaches to cope with the complicated and diversified society. In particular, field studies and opportunity to use the dangerous educational appliances have been increasing in order to cope with the desires of education consumers requiring diversity and the individuality of students has been strengthened. In accordance with the trends above, the school accidents have been gradually increasing in recent days. Thus, this paper aims to propose the suggestions to teachers in real education fields by investigating the problems in compensation system of School Safety and Insurance Association against which the victim s of any school safety accidents firstly claim for the damages, the problems in the present system of the Association and how to improve the system in terms of the payment scope of the Association.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.573-583
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• 2011

In this paper, we propose an occlusion compensation algorithm which is used for virtual view generation. In general, since occlusion region is recovered from neighboring pixels by taking the mean value or median value of neighbor pixels, the visual characteristics of a given image are not considered and consequently the accuracy of the compensated occlusion regions is not guaranteed. To solve these problem, we propose an algorithm that considers primary visual characteristics of a given image to compensate the occluded regions by using seam carving algorithm. In the proposed algorithm, we first use Sobel mask to obtain the edge map of a given image and then make it binary digit 0 or 1 and finally thinning process follows. Then, the energy patterns of original and thinned edge map obtained by the modified seam carving method are used to compensate the occlusion regions. Through experiments with many test images, we verify that the proposed algorithm performed better than conventional algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.8
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• pp.115-122
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• 2017

In this paper, we propose a novel power factor compensation system using slidac. The proposed power factor compensation system compensates the power factor by adjusting the output voltage of the slidac. In the conventional power factor compensation system using capacitor bank method, the power factor compensation error occurs depending on the load condition due to the limitation of the compensation capacitor capacity. However, the proposed system can finely change slidac output voltage applied to the capacitor, therefore power factor can be compensated up to 100% without error. We compare the proposed system with the conventional system, and confirm that the proposed system has excellent power factor compensation performance through simulations and experiments. If the proposed power factor compensation system is applied to an industrial field, a power factor compensation performance can be maximized. As a result, it is possible to reduce of electricity prices, reduce of line loss, increase of load capacity, ensure the transmission margin capacity, and reduce the amount of power generation.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.569-580
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• 2002

The purpose of this study was to analyze the problem-solving process of student's compensation con-cept.For this purpose, verbal interactions during activities were audio-taped, transcribed, and analyzed. And classroom observation and interview with students were carried out. Students who were superior in mathematical operations tended to explain compensation concept using proportionality. On the other hand, students who had low level of conservation concept can not connect 'relation of two variables' with 'conservation of equilibrium' at the formation process of com-pensation concept. Students who succeed in the formation of compensation concept showed high level of conservation concept. To promote the formation of compensation concept, it is necessary that how to develop proportional concept and conservation concept as closely related with compensation concept should be studied.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.516-527
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• 2008

This paper introduces a derivation method of both P-SKIP and B-SKIP modes for illumination compensation in the multi-view video coding scheme. In this proposed method, mismatches between IC flag and IC offset in P-SKIP mode are removed, and also computational complexity is far reduced in B-SKIP mode in comparison to a multi-view video coding scheme. In simulation results, proposed method has the almost same coding efficiency in comparison with the referenced coding scheme. However computational complexity in 11m-time decoding process is tremendously reduced, such that the average number of blocks that should be processed in P-SKIP mode is saved in about 7.47%, and the average number of operations per block in B-SKIP mode is saved in about 50.36% and corresponding average decoding time per block is also saved in 46%.