• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.171-172
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• 2014

본 논문에서는 전기자동차용 양방향 인터리브드 전류원 공진형 컨버터를 제안한다. 제안한 전류원 공진형 컨버터(Current-fed Resonant Converter, CRC)를 인터리빙하여 출력 전류 리플을 이론적으로 완전히 제거함으로써 출력필터의 크기를 줄일 수 있다. 또한, 부하에 관계없이 스위치와 다이오드가 전 부하영역에서 ZCS 턴온 및 턴오프가 가능하여 스위칭 손실이 작은 장점이 있다. 2kW급 시작품을 제작하여 제안하는 컨버터의 타당성을 검증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.231-237
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• 2007

The torque ripple of the hydraulic pumps for the Electro-hydrostatic Actuators can disturb the cylinder position control under slewing speed operation condition. In principle, the periodic change of the reaction torque generated by a piston type pump is highly dependent on the waveform of its cylinder chamber pressure. In case of uni-directional pumps operating at constant speed, the transient overshoot and rising slope of the cylinder pressure can be adjusted by the precompression angle and notch shape of their valve plates. Therefore, the influence of the valve plate geometry on the torque ripple magnitude of a bent-axis type piston pump for EHA application was investigated in this study. The results showed that any improvement of the torque ripple of such a bi-directional pump can not be achieved by modifying the valve plate geometry, regardless of its operation speed.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.17-25
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• 2008

Whether rating curves are used in practice or new ones are derived, the characteristics of regression analysis are often neglected. For example, a discharge rating curve, which is established from a regression of observed water levels (H) on observed flowrates(Q), is sometimes used for estimating a design water level corresponding to a simulated design flood runoff. However, if independent and dependent variables are changed with each other, the regression equation is changed in existing regression analysis, which is derived from vertical errors between observed data and regression line. Thus, regression equations should not be applied inversely. To avoid this problem, A new two-way variable least-squares regression analysis is proposed. The new method was applied to the rating curves of five water level stations on main stream of Nakdong River. The three kinds of regression models, which are respectively regression of Q versus H (model 1), H versus Q (model 2) and two-way (model 3), showed that the new method can reduce inadvertent mistakes when applied in practice.

• Proceedings of the Korea Contents Association Conference
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• 2016.05a
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• pp.153-154
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• 2016

소셜미디어는 다대대의 양방향적 소통으로 정보전달의 신속성과 함께 인간관계의 네트워크 확장이 가능한 광고의 매체로서 주목을 받고 있어 그 활용사례로 영국의 존루이스 백화점 크리스마스 캠페인 광고 "Bear and Hare"의 감성 스토리를 활용한 소셜 커뮤니케이션 전략을 분석하였다.

• Korean journal of communication and information
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• v.46
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• pp.9-36
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• 2009

In a competitive media environment, Internet Protocol television (IPTV) has gained appeal because of its essential characteristics, 'Internet and Interactivity'. Our study aims to explore predictors that affect IPTV-VOD adoption within the context of competing media (i.e., existing multi-channel video programming services, such as cable television and digital broadcasting satellite services). In addition, this study examines if IPTV-VOD functions as a substitute for existing multi-channel services, such as cable television and direct broadcasting satellite services. A self-report survey through face-to-face interviews was conducted in Seoul metropolitan area and other six big cities. Our findings showed that primary factors for adopting an IPTV-VOD are: age of user, subjective importance of terrestial broadcasting services, real-time terrestrial broadcasting services, and other interactive service characteristics, such as time-shifting. Also, IPTV-VOD services were found to be a substitute for existing multi-channel video programming services.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.610-620
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• 2005

The current study investigates factors affecting intent to use of T-Commerce in enhanced TV programs. from the perspective of e-commerce users who have experienced terrestrial data broadcasting services. The research model hypothesizes the relationship among independent variables such as perceived usefulness, perceived ease of use, and the dependent variable, intent to use of T-Commerce. In addition, the moderating effect of user innovativeness is also analyzed. The results reveal the significant and positive relationship between perceived usefulness of e-commerce and intent to use of T-Commerce. Besides, the moderating role of user innovativeness is confined to the effect of the perceived usefulness on intent of use of T-Commerce. The findings of this study provide an implication that customer attracting strategies for potential T-Commerce users have to be differentiated based on the status in the T-Commerce development process.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.6
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• pp.561-571
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• 2014

The standards of ventilation system for bi-directional tunnel have not been established now. For this reason, with regard to the bi-directional tunnel below 1km, some problems have been appeared in ventilation capacity designing and in determining whether the mechanical ventilation system is needed or not for each case. In this study, we examine the characteristics of natural ventilations, analyze ongoing ventilation design cases for bi-directional tunnels and classify those cases into two groups. This study is carried out about the capability of using natural ventilating system by calculation of reasonable ventilation capacity in bi-directional tunnel and review of relationship between natural wind speed ($Vr^*$) and required speed(Vreq). This paper aims at providing a basis data for bi-directional tunnel ventilation design standards.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1844-1850
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• 2016

The bilateral filter can reduce the noise while preserving details computing the filtering output at each pixels as the average of neighboring pixels. In this paper, we propose a real-time system based on window division. Overall performance is increased due to the parallel architectures which computes five rows in the kernel window simultaneously but with pipelined scheduling. We consider the tradeoff between the filter performance and the hardware cost and the bit allocation has been determined by PSNR analysis. The proposed architecture is designed with verilogHDL and synthesized using Dongbu Hitek 110nm standard cell library. The proposed architecture shows 416Mpixels/s (397fps) of throughput at 416MHz of operating frequency with 132K gates.

• The KIPS Transactions:PartB
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• v.10B no.5
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• pp.561-566
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• 2003

This paper proposes a new algorithm that generates smooth and realistic transition views from one viewpoint to another view point on the panorama based navigation system. The proposed algorithm is composed with two steps. One is prewarping that aligns the viewing direction in two panorama image, the other is bidirectional disparity morphing (BDM) that generates the intermediate scene from the aligned panorama images. For the prewarping, first of all, we compute the phase correlation between two images in order to get the information such as the displacement, rotation, and scale. Then we align the original images using these information. As soon as finishing the prewarping, we compute the block based disparity vectors (DVs) and smooth them using the two occluding patterns. As we apply these DVs to the BDM, we can get the elaborate intermediate scenes. We make an experiment on the proposed algorithm with real panoramic images and we can get the satisfactory results.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.427-432
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• 2019

In this paper, we propose a home monitoring system using sound event detection based on a bidirectional gated recurrent neural network for the hard-of-hearing. First, in the proposed system, packet loss concealment is used to recover a lost signal captured through wireless sensor networks, and reliable channels are selected using multi-channel cross correlation coefficient for effective sound event detection. The detected sound event is converted into the text and haptic signal through a harmonic/percussive sound source separation method to be provided to hearing impaired people. Experimental results show that the performance of the proposed sound event detection method is superior to the conventional methods and the sound can be expressed into detailed haptic signal using the source separation.