• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.557-559
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• 2004

The study of applying wavelet transform in power cable system fault location has been recognized by many researchers and investigated. For performance of fault location, the fault generated transients can be captured at one end of the cable or both ends. Between two approaches, single-ended approach is less expensive and more reliable as it doesn't need communication link between the ends of the cable. So, we performs the approach based on the one. In this paper, we are going to introduce a new algorithm to discriminate the transient and the reflected signal using wavelet coefficient. For wavelet transform, the stationary wavelet transform(SWT) is applied instead of conventional DWT because SWT has redundancy properties which is more useful in noisy signal processing.

• 한국철도학회논문집
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• 제19권3호
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• pp.351-362
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• 2016

본 연구의 목적은 고속철도 역사시설 및 열차서비스 전반에 관한 서비스 만족도를 측정하여 고객만족에 영향을 미치는 주요 서비스요인을 도출하고 그 관계를 밝히는 데 있다. 이를 위해 고속철도 이용객 202명을 대상으로 설문을 수행하여 분석한 결과, 역사 및 열차 관련 서비스에 관한 설문문항 63개 중, 주차관련서비스, 역사편의시설관련서비스, 발권서비스, 열차 내 서비스, 열차 내 환경 등의 다섯 가지 주요 서비스요인이 도출되었다. 구조방정식모형을 통한 가설검증 결과, 주차관련서비스는 열차 내 서비스에 직접적인 영향을 미치지 않으며, 그 외 역사편의시설 및 발권서비스는 열차 내 서비스 및 환경에 각각 긍정적인 영향을 미치는 선행요소로 나타났다. 또한 열차 내 서비스와 환경요인은 고객의 만족을 강화시키는 주요한 변수로 검증되었다. 따라서 역사시설 및 열차서비스의 경험은 철도서비스만족에 긍정적인 영향을 미치는 것을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1390-1393
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• 2006

Data spread over 11 years (1986-1996) pertaining to a synthetic population developed by inter se mating of half-breds of Corriedale and Russian Merino with Nali maintained at CCS Haryana Agricultural University, Hisar were utilized for the estimation of genetic parameters for growth traits. The means for birth weight (BWT), weaning weight (WWT), six month body weight (SWT), yearling weight (YWT), preweaning daily gain (PRW) and post weaning daily gain (POW) were 3.35 kg, 10.79 kg, 13.28 kg, 18.96 kg, 82.6 gm and 27.6 gm, respectively. The effects of year and season of birth and sex of lamb were significant for all the traits under study except the effect of season of birth for WWT, SWT and PRW. No definite trend was observed over the years for the averages of body weight and gain. Lambs born during the spring season performed better for BWT, WWT and PRW while the performance of lambs born during autumn was better for the other traits included in the study. The male lambs were heavier than the females for body weight at all stages and gain in weight. The heritability estimates for WWT and PRW were low; for BWT and SWT were moderate and for YWT and POW were high. Birth weight had high heritability and high genetic correlations with subsequent body weights and gains but due to the presence of a maternal effect on BWT and WWT, a sequential selection procedure is recommended for the improvement of growth rate in sheep.

• 한국산학기술학회논문지
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• 제15권1호
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• pp.367-376
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• 2014

이 연구의 목적은 건강한 남자 14명을 대상자로 단기간의 지구성 훈련과 지구성 운동에 웨이트 운동을 병행한 복합훈련이 골격근 섬유의 형태 및 골격근 내 산화적 효소의 활성도에 미치는 영향을 구명하고자 하였다. 지구성 트레이닝 집단은 최대심박수의 70~80% 에서 40분간 자유형으로 수영을 6주간 실시하였으며 복합 트레이닝 집단은 동일한 수영을 실시한 후 웨이트 트레이닝을 추가로 실시하였다. 근섬유 횡단면적에 있어 복합훈련 집단과 지구성 훈련 집단 간에 차이가 나타나지 않았으며 훈련기간에 따라 복합훈련 집단에서 지구성 훈련 집단보다 증가한 것으로 나타났다. 모세혈관 수에 있어서도 집단 간 차이는 나타나지 않았으며 훈련기간에 따라 복합훈련 집단에서 지구성 훈련 집단보다 증가한 것으로 나타났다. 유산소성 대사 효소 중 CS, ${\beta}$-HAD 그리고 CPT의 활성도는 훈련형태에 따른 차이는 통계적으로 나타나지 않았으나 복합훈련 집단에서 지구성 훈련 집단에서 보다 더 큰 증가의 폭을 나타냈다. 이와 같은 결과를 종합해 볼 때 유산소성 훈련만을 실시할 때 보다 유 무산소 운동이 복합적으로 구성되어 있는 훈련의 수행이 근섬유의 에너지 대사 관련 효소들의 활성도 증가와 근 세포 모세혈관의 발달에 보다 효과적이라는 결론을 도출할 수 있었다.

• Tribology and Lubricants
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• 제28권1호
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• pp.19-26
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• 2012

Rolling contact fatigue of an urban railway wheel was analysed during its rolling. A FEM analysis was performed using a 3D modelling of rail and wheel, considering the slope of the rail and nonlinear isotropic and kinematic hardening behavior of the rail and the wheel. The maximum von-Mises stress and contact pressure between the rail and wheel were 656.9 MPa and 1111.4 MPa, respectively, under axial load of 85 kN with friction coefficient of 0. The fatigue initiation life prediction relationships by strain-lifetime (${\varepsilon}$-N) and Smith-Watson-Topper method were drawn for the wheel steel as follows: $N_i=7.35{\times}10^6{\times}SWT^{-3.56}$ and $N_i=5.41{\times}10^{-9}{\times}(\frac{{\Delta}{\varepsilon}}{2})^{-5.77}$. The fatigue lifetimes of the wheel due to rolling contact were determined to be infinite by ${\varepsilon}$-N and SWT methods.

• 한국안전학회지
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• 제30권3호
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• pp.1-6
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• 2015

Self-piercing riveting (SPR) is receiving more recognition as a possible and effective solution for joining automotive body panels and structures, particularly for aluminum parts and dissimilar parts. In this study, static strength and fatigue tests were conducted using coach-peel and cross-tension specimens with Al-5052 plates for evaluation of fatigue strength of the SPR joints. For the static experiment results, the fracture modes are classified into pull-out fracture due to influence of plastic deformation of joining area. During the fatigue tests for the coach-peel and cross-tension specimens with Al-5052, interface failure mode occurred on the top substrate close to the rivet head in the most cycle region. There were relationship between applied load amplitude $P_{amp}$ and life time of cycle N, $P_{amp}=715.5{\times}N^{-0.166}$ and $P_{amp}=1967.3{\times}N^{-0.162}$ were for the coach-peel and cross- tension specimens, respectively. The finite element analysis results for specimens were adopted for the parameters of fatigue lifetime prediction. The relation between SWT fatigue parameter and number of cycles was found to be $SWT=192.8N_f^{-0.44}$.

• 한국콘텐츠학회논문지
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• 제11권2호
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• pp.113-125
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• 2011

본 논문에서는 미디어 아트 콘텐츠 저작도구인 ECAS(Exhibition Contents Authoring System)와 그 개발 방법을 소개한다. ECAS는 기존의 저작도구가 가진 텍스트 기반의 프로그래밍 방식의 문제점을 개선하기 위해 그래픽 사용자 인터페이스를 기반으로 개발되었으며, 그래픽 사용자 인터페이스의 효율적인 구현을 위해 Eclipse가 제공하는 GMF(Graphical Modeling Framework) 기법을 사용하였다. ECAS의 속도 및 성능 향상을 위해 SWT(Standard Widget Toolkit), JIT(Just-In-Time)와 같은 속도 향상 기법들을 활용하였다. 얼굴 검출 기능, 사운드 효과 기능, 하드웨어 연동 기능 등의 주요 기능들을 중심으로 기존의 저작도구와 작품 구현 비교를 통해 ECAS의 편리성과 효율성을 보였다.

• 한국항행학회논문지
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• 제22권5호
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• pp.359-366
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• 2018

본 논문은 FBG센서를 항공기 날개 내부에 설치한 CTLS항공기를 이용하여 데이터를 받아 잡음제거를 수행하였다. 잡음제거를 위하여 이동불변의 특성을 지닌 정상 웨이블릿 변환 기법을 제시하였다. CTLS와 같이 복합재 내부에 FBG센서를 설치하게 될 경우 접착제 층 사이에 크고 작은 빈공간과 미 접착부분이 생기게 되고, 신호갈라짐 (split problem) 현상이 발생하게 된다. FBG센서 자체가 전자기적 잡음에 영향을 받지 않지만 광원이나 광 검출기, 신호처리장치의 경우 전원을 사용하는 전자부품이기 때문에 이러한 전자기파의 영향을 받아 오차가 발생하게 된다. 이렇게 발생한 오차를 실험결과를 통하여 정상 웨이블릿 변환을 이용하여 잡음을 제거하고 보다 정확한 데이터 검출을 할 수 있음을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.476-484
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• 2018

The high capacity audio watermarking algorithms are facing a main challenge in satisfying the robustness against attacks especially on de-synchronization attacks. In this paper, a robust and a high capacity algorithm is proposed using segment selection, Stationary Wavelet Transform (SWT) and the Quantization Index Modulation (QIM) techniques along with new synchronization mechanism. The proposed algorithm provides enhanced trade-off between robustness, imperceptibility, and capacity. The achieved watermarking improves the reliability of the available watermarking methods and shows high robustness towards signal processing (manipulating) attacks especially the de-synchronization attacks such as cropping, jittering, and zero inserting attacks. For imperceptibility evaluation, high signal to noise ratio values of above 22 dB has been achieved. Also subjective test with volunteer listeners shows that the proposed method has high imperceptibility with Subjective Difference Grade (SDG) of 4.76. Meanwhile, high rational capacity up to 176.4 bps is also achieved.

• 한국산업융합학회 논문집
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• 제20권2호
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• pp.195-204
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• 2017

Predicting the failure life of automated manufacturing systems can reduce overall downtime, maintenance costs, and total plant operation costs. Therefore, there is a growing interest in fatigue failure mechanisms as the safety or service life assessment of manufacturing systems becomes an important issue. In particular, fretting fatigue is caused by repeated tangential stresses that are generated by friction during small amplitude oscillatory movements or sliding between two surfaces pressed together in intimate contact. Previous studies in fretting fatigue have observed size effects related to contact width such that a critical contact width exists where there is drastic change in the fretting fatigue life. However, most of them are the two-dimensional finite element analyses based on the plane strain assumption. The purpose of this study is to investigate the contact size effects on the three-dimensional finite element model of a finite width of a flat specimen and a cylindrical pad exposed to fretting fatigue. The contact size effects were analyzed by means of the stress and strain averages at the element integration points of three-dimensional finite element model. This study shows that the fretting fatigue life of manufacturing systems can be predicted by three-dimensional finite element analysis based on SWT critical plane model.