• Proceedings of the KSME Conference
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• 2004.04a
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• pp.462-467
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• 2004

In order to determine the most suitable material system which can achieve the lightweight design and fulfill the design requirements of carbody structures of Korean Tilting Train eXpress (TTX), aluminum carbody, composite carbody, and hybrid carbody combined with aluminum and composite structures were considered in present study. The finite-element analysis was used to verity the design requirements of the TTX carbody structures with the material system being considered in the design stages. The stresses in the carbody structures and deflections of underframe against static load cases were checked as design criteria. The results show that the hybrid carbody structures are beneficial with regard to weight savings and structural integrity when compared to aluminum and composite carbody structures.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.325-326
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• 2007

본 논문에서는 H.264 동영상 표준 부호화 방식의 움직임 추정을 위한 고속 다중 참조 프레임 선택 기법에 대해 제안한다. 다중 참조 프레임에 대한 움직임 추정 수행 시 참조 프레임 수에 비례하여 계산량이 증가하는 반면에 동영상의 특성에 따라 부호화 효율의 이득없이 계산량만을 소비하는 경우가 발생된다. 따라서 본 논문에서는 각 참조 프레임에서의 움직임 추정에 대한 SAD값의 비교를 통해 다중 참조 프레임 움직임 추정의 종료 시점을 적응적으로 결정한다 실험 결과를 통해 5개의 참조프레임 사용을 기준으로 제안된 기법을 사용하였을 때 움직임 추정에 소요되는 시간은 가용한 모든 참조 프레임에 대해 움직임 추정을 수행하는 방식 대비 평균 50%정도 감소하였으며, PSNR 및 발생 비트율 측면에서 거의 동일한 성능을 유지함을 확인할 수 있었다.

• Journal of Wellbeing Management and Applied Psychology
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• v.2 no.1
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• pp.35-39
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• 2019

This paper presents two social and academic studies on the boundary between cultural production and consumption. The first line of the study on cultural omnivore analyzes the choice of heterogeneous audiences in the face of various cultural offerings. The second line is a study of market categories, which analyzes the responses of peer audiences to objects with different levels of category code compliance. As such, this paper developed a heterogeneous audience model to evaluate objects of different types. This allows us to consider two dimensions of cultural preference: diversity and orientation of selection. To this end, this paper proposes a new analytical frame work to map consumption behavior on these two dimensions. The results suggest that one type of target that values diversity and transformation is particularly resistant to those that span boundaries. We test this argument in the analysis of two large data sets on film and restaurant reviews. Overall, our findings can extend beyond cultural consumption. Outline variability of contextual individuals or individuals in the same situation can cross cultural boundaries even if they are not intentionally pursuing such hybridism.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1124-1136
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• 2017

Direct Power Control technique has become popular in the grid connected Voltage Source Converter (VSC) applications due to its simplicity, direct voltage vector selection and improved dynamic performance. In this paper, a direct method to determine the effect of voltage vector on the instantaneous active and reactive power variations is developed. An alternative Look Up Table is proposed which minimizes the commutations in the converter and results in minimum reactive power variation. The application of suggested table is established for Shunt Active Power Filter (SAPF) application. The Predictive Direct Power Control method, which minimizes apparent power variation, is further investigated to reduce commutations in converters. Both the methods are validated using 2 kVA laboratory prototype of Shunt Active Power Filters (SAPF).

• MALSORI
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• no.60
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• pp.191-201
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• 2006

Discrimination between speech and music is important in many multimedia applications. Previously we proposed a new parameter for speech/music discrimination, the mean of minimum cepstral distances (MMCD), and it outperformed the conventional parameters. One weakness of MMCD is that its performance depends on range of candidate frames to compute the minimum cepstral distance, which requires the optimal selection of the range experimentally. In this paper, to alleviate the problem, we propose a multi-dimensional MMCD parameter which consists of multiple MMCDS with combination of different candidate frame ranges. Experimental results show that the multi-dimensional MMCD parameter yields an error rate reduction of 22.5% compared with the optimally chosen one-dimensional MMCD parameter.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.141-142
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• 2015

본 논문에서는 동기 좌표계 비례 적분(PI) 전류 제어기의 이득 산정에 따른 계통 외란 발생 시 제어기의 응답 특성을 연구하였다. PI 전류 제어기의 이득 선정 시 플랜트의 시정수와 적분기 시정수를 같게 설정하는 극점-영점 상쇄 기법을 사용하여 전류 제어 특성을 결정할 수 있다. 그러나 극점-영점 상쇄 기법을 통해 이득이 선정된 전류 제어기는 계통에 외란 발생시 제어기 응답 특성이 느려진다. 적분기 시정수를 샘플링 주기를 이용하여 선정한다면 계통 외란에 강인한 특성을 갖게 된다. 제안된 방법은 각각 선정된 적분기 시정수를 가지고 외란에 대한 주파수 응답 특성과 데드 타임이 추가된 계통연계형 인버터 시뮬레이션 결과를 비교 분석하여 제안된 적분기 시정 수 선정 방법이 외란에 더 강인함을 검증하였다.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.55.2-55.2
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• 2018

The Wide-field Infrared Survey Explorer (WISE) mission enabled efficient selection of Active Galactic Nuclei (AGN) with high luminosities and large obscuration. According to the merger driven AGN powering scenarios, luminous and obscured AGN are in a stage where they go through feeding of gas accretion into the central black hole, and feedback to the host galaxy through outflows. We report the rest-frame UV-optical spectra of Hot Dust Obscured Galaxies (Hot DOGs) at z~2, WISE color-selected to be extremely reddened AGN. Most of the targets show blueshifted and broadened [OIII] line profiles indicative of ionized gas outflows. We present the occurrence and strength of the outflows, and discuss the impact of luminous, obscured AGN activity on their hosts.

• Structural Engineering and Mechanics
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• v.78 no.1
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• pp.67-75
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• 2021

This work studies the behaviour of a steel portal frame selection under fire exposure, considering both span lengths and fire exposure times as variables. Such structures combine carbon steel (S275), fireproof micro-alloyed steel (FR), and coatings of intumescent paint with variable thicknesses, improving thereby the flame retardant behaviour of the steel structure. Thus, the main contribution of this study is the optimization of the portal frames by combining both steels, analysing the resulting costs influence on the final dimensions. Besides, the topological optimization of each steel component within the structure is also defined, in accordance with the following variables: weather conditions, span, paint thickness, and cost of steel. The results mainly confirmed that using both FR and S275 grades with intumescent painting is the Pareto optimum when considering performance, feasibility and costs of such portal frames widely used for industrial facilities.

• Journal of Information Processing Systems
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• v.18 no.2
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• pp.235-244
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• 2022

Many new techniques have been adopted in HEVC (High efficiency video coding) standard, such as quadtree-structured coding unit (CU), prediction unit (PU) partition, 35 intra-mode, and so on. To reduce computational complexity, the paper proposes two optimization algorithms which include fast CU depth range decision and fast PU partition mode decision. Firstly, depth range of CU is predicted according to spatial-temporal correlation. Secondly, we utilize the depth difference between the current CU and CU corresponding to the same position of adjacent frame for PU mode range selection. The number of traversal candidate modes is reduced. The experiment result shows the proposed algorithm obtains a lot of time reducing, and the loss of coding efficiency is inappreciable.

• Computers and Concrete
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• v.30 no.4
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• pp.269-276
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• 2022

In this paper, frequency vibrations of double-walled carbon nanotubes (CNTs) has been investigated based upon nonlocal elastic theory. The inference of small scale is being perceived by establishing nonlocal Love shell model. The wave propagation approach has been operated to frame the governing equations as eigen value system. An innovational nonlocal model to examine the scale effect on vibrational behavior of armchair, zigzag and chiral of double-walled CNTs. An appropriate selection of material properties and nonlocal parameter has been considered. The influence of dimensionless nonlocal parameter has been studied in detail. The dominance of end condition via nonlocal parameter is explained graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.