http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Fast Mode Decision Algorithm for Spatial Scalability in Scalable Video Coding
HaHyun Lee,Jung Won Kang,Jeong-Ju Yoo 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
SVC is being standardized as an extension of H.264/AVC by JVT of ITU-T VCEG and ISO/IEC MPEG. Since SVC is an extension of H.264, it also uses the variable block size and a rate-distortion optimization (RDO) technique for each macroblock. For sptial enhancement layer, SVC includes a new mode as well as the modes available in H.264/AVC. As a result of these, computational complexity in spatial enhancement layer is more increased than base layer. To overcome this, we propose a fast mode decision algorithm for spatial enhancement layer of SVC using the MB partitioning of base layer and the property of all zero cofficient block. Exprimental results show that the proposed algorithm can siginficantly reduce the computational complexity without compromising the coding efficiency.
Enhanced Block-Based Adaptive Loop Filter with Multiple Symmetric Structures for Video Coding
Hahyun Lee,Sung-Chang Lim,Seyoon Jung,Jongho Kim,Jin Soo Choi,최해철 한국전자통신연구원 2010 ETRI Journal Vol.32 No.4
In this letter, we present an enhanced block-based adaptive loop filter (E-BALF) with multiple filter symmetric structures. The E-BALF adapts various filter symmetric structures in a rate-distortion optimization sense, reflecting the statistical properties of each image in a video sequence. Experimental results show that the proposed method achieves a reduction in the Bjøntegaard delta (BD)-bitrate by an average of 9.60% compared with Joint Model 11.0 of H.264/AVC. Compared to the state-of-the-art BALF, a reduction of up to 1.13% in BD- bitrate is achieved.
고해상도 영상에 대한 MPEG-2 / H.264 / HEVC 비디오 코덱의 성능 비교 분석
이하현(Hahyun Lee),김종호(Jongho Kim),김휘용(Hui Yong Kim),최진수(Jin Soo Choi) 한국방송·미디어공학회 2011 한국방송공학회 학술발표대회 논문집 Vol.2011 No.7
본 논문에서는 JCT-VC(Joint Collaboration Team on Video Coding)에서 표준화가 진행 중인 HEVC(High Efficiency Video Coding)의 Test Model 인 HM1.0과 현재 디지털 방송, 통신, 저장 매체 등 다양한 응용 분야에 사용되고 있는 범용 비디오 코덱들 간의 객관적, 주관적 측면에서의 부호화 성능을 비교한다. 이를 통해 HEVC의 현재 성능 수준에 대한 평가 결과를 보이고, 활용 가능성에 대해 결론을 맺는다. 비교 대상 코덱으로는 H.264/AVC 표준의 S/W 기반인 VideoLAN Project의 x264와 MPEG-2 표준으로 Harmonic사의 H/W기반의 최신형 실시간 인코더인 Electra8000을 사용하였다. 총 5개의 HD(1920x1080)영상에 대한 객관적 성능 비교 결과, HM1.0이 x264 대비 평균 44.93%의 BD-rate 감소와 평균 1.65%의 BD-PSNR 증가를 보였고, Electra8000에 대해서도 월등히 높은 성능차를 보였다. 주관적 화질 비교 결과 동일 PSNR 조건하에서 HM1.0이 범용 비디오 코덱들보다 주관적 화질이 유사하거나 좀 더 나음을 보였다.
이진호(Jinho Lee),김휘용(Hui Yong Kim),임성창(Sung-Chang Lim),이하현(Hahyun Lee),최진수(Jin Soo Choi) 한국방송·미디어공학회 2011 한국방송공학회 학술발표대회 논문집 Vol.2011 No.7
본 논문에서는 화면내 예측의 계산 복잡도를 감소시키기 위한 방법을 제안한다. HM2.0 의 화면내 예측 방법인 각도에 의한 예측(Angular prediction)은 예측 대상블록 내부의 각 샘플이 예측하기 위해 사용하는 참조샘플로부터 정수단위의 위치에 있지 않을 경우 참조 샘플들을 보간 하여 예측을 수행한다. 이러한 방법은 예측 대상 블록의 크기가 커질수록 보간 하는 횟수가 증가하고 계산 복잡도가 증가하는 단점이 있다. 제안하는 방법은 한번의 보간으로 복수의 샘플들을 예측함으로써 보간 횟수를 줄이고 결과적으로 계산의 복잡도를 줄인다. PU_32x32 에 대해 제안하는 방법을 적용하였을 경우, 보간하는 횟수는 HM2.0 대비 1/2 배 또는 1/4 배 가까이 감소하고 성능 저하는 High-Efficiency(HE)에서 0.1% 또는 0.2% 정도로 미미하게 나타났다.
U - City 서비스 분류체계의 적합성에 관한 질적 휴리스틱 분석
이정우(Jungwoo Lee),김하현(Hahyun Kim),이민정(Minjung Lee) 한국IT서비스학회 2012 한국IT서비스학회지 Vol.11 No.1
KUbiquitous city(U - City) is a recent trend in urban planning and management across the globe. Currently, several typologies were developed and presented classifying U - City services, but validation research of these typologies are scarce. In this study, efforts were made to qualitatively validate the usability and practicality of a typology of u - city services. Using 228 U - City services identified in previous studies, classifying exercises were conducted against a typology. Three experts were involved in this expert heuristic exercise, against a most popularly used and comprehensive typology of U - City services. Findings indicates that the selected typology is high on comprehensive exhaustiveness, and empirical applicability while low on mutual exclusivity, simplicity and theoretical contribution. Implications for the typology improvement are suggested followed by limitations and directions for further research.
Park, Hahyun,Lee, Jin-Young,Park, Sunwoo,Song, Gwonhwa,Lim, Whasun Elsevier 2020 Journal of hazardous materials Vol.385 No.-
<P><B>Abstract</B></P> <P>Fipronil has been widely used in agriculture to prevent aggressive insects from damaging agricultural products. Fipronil residues circulate in the environment and they have been detected in non-targeted organisms in aquatic environments. To study the effect of fipronil toxicity on environmental health, 6 h post fertilization (hpf) zebrafish embryos were treated with fipronil for 72 h. LC<SUB>50</SUB> value was obtained by applying varying concentrations of fipronil to zebrafish embryos for 72 h. As zebrafish embryos are useful vertebrate models for studying developmental and genetic findings in toxicology research, they were exposed to fipronil to study detailed elucidating mechanisms with hazardous end points of toxicity. Cell cycle arrest-related apoptosis supported pathological alterations, such as increased mortality, shortened body length, and reduced hatchability. Furthermore, observed heart defects, including edema and irregular heartbeat were caused due to abnormal blood circulation. In transgenic zebrafish models (<I>fli1:eGFP</I> and <I>olig2:dsRED</I>), disrupted blood vessel formations were indicated by <I>eGFP</I> <SUP>+</SUP> endothelial cells. Moreover, neurogenic defects were observed by studying <I>dsRED</I> <SUP>+</SUP> motor neurons and oligodendrocytes. This study demonstrates fipronil accumulation in aquatic environment and its ability to impair essential processes, such as angiogenesis and neurogenesis during early developmental stage of zebrafish, along with general developmental toxicity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fipronil reduces cell proliferation with cell cycle arrest of zebrafish embryos. </LI> <LI> Fipronil leads to mortality, shortened body length, and reduced hatchability. </LI> <LI> Fipronil causes edema and irregular heartbeat through abnormal blood circulation. </LI> <LI> Fipronil shows neurogenic defects during early developmental stage of zebrafish. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic diagram of fipronil induced developmental toxicity in zebrafish embryos. Naturally exposed fipronil bioaccumulates within environmental circulation. In laboratory condition, after 72 h fipronil exposure, significant physiological abnormalities are observed, including increasing mortality, shortened body length, irregular hatching, and multiple damaged developing organs by visual observation. Higher apoptosis generation contributes to pathological characteristics in treated embryos (white arrows indicate highly detected apoptotic cells). In comparison of solvent control group, eGFP + endothelial cells in developing vasculature show anti-angiogenic effect of fipronil on zebrafish embryos, including failure of endothelial cells tube formation (asterisks indicate undeveloped ISVs and DLAV). Likewise, dsRED + cells in developing motor neurons indicate anti-neurogenic effect of fipronil (asterisk indicates insufficient motor neuron length). Inhibited gene expression related to these development processes support developmental toxicity.</P> <P>[DISPLAY OMISSION]</P>
Developmental toxicity and angiogenic defects of etoxazole exposed zebrafish (Danio rerio) larvae
Park, Hahyun,Lee, Jin-Young,Park, Sunwoo,Song, Gwonhwa,Lim, Whasun Elsevier 2019 Aquatic toxicology Vol.217 No.-
<P><B>Abstract</B></P> <P>Etoxazole, a chitin synthesis inhibitor, is widely used to control insects and mites by causing developmental defects. Despite the many advantages of pesticides, the inhibitory effects of most pesticides including etoxazole are based on biochemical reaction and their widespread application is considered as a major risk to human health and the environment because of bioaccumulation and non-target toxic effects. Though used in agricultural area, the pesticide residues run off through rivers or ocean, where diverse aquatic organisms live. Since there are no studies evaluating the risks of etoxazole exposure in embryogenesis of aquatic organisms, we investigated the adverse effects of etoxazole on development and angiogenesis in zebrafish embryos, which are considered to be an effective model for detecting ecotoxicological effects of widely used compounds, especially affecting aquatic organisms. Etoxazole induced yolk sac and heart edema, as well as loss of viability, abnormal heart rate, and developmental deficiency. Through a mechanistic approach, we also showed that etoxazole caused reactive oxygen species accumulation, inhibited the expression of cell cycle activating genes, and induced apoptosis. In addition, we investigated effects of etoxazole on cardiovascular development by demonstrating the loss of vascular structure in response to etoxazole exposure in fli1:eGFP transgenic zebrafish model. Collectively, this first assessment demonstrating the effects of etoxazole on embryogenesis and cardiovascular development provides clear evidence for the toxicity of etoxazole and contributes important data towards formulating safety guidelines on the potential hazards of etoxazole for aquatic environment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Etoxazole induces yolk sac and heart edema in zebrafish embryos. </LI> <LI> Etoxazole treatment increases ROS accumulation in zebrafish embryos. </LI> <LI> Etoxazole treatment inhibits cell cycle regulatory genes in zebrafish embryos. </LI> <LI> Etoxazole inhibits cardiovascular development in zebrafish embryos. </LI> </UL> </P>