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최해철(Haechul Choi),이경일(Kyung Il Lee),강정원(Jung Won Kang),배성준(Seong-Jun Bae),유정주(Jeong-Ju Yoo) 한국방송·미디어공학회 2007 방송공학회논문지 Vol.12 No.6
근래의 무선망 및 인터넷의 초고속화에 따라 풍부한 멀티미디어에 대한 사용자의 요구가 증대 되고 있으며, 이동 통신의 활성화 및 DMB(Digital Media Broadcasting)와 같은 통방융합 서비스의 등장으로 여러 네트워크 망을 통해 다양한 성능을 가진 단말로의 멀티미디어 서비스가 이루어 지고 있다. 이러한 환경 변화에 따라 비트율을 줄이기 위한 비디오 압축 부호화 기술뿐만 아니라 시변의 전송 조건, 전송망 특성, 다양한 단말 성능, 사용자 선호도 등에 대한 비디오의 적응 기술에 관심이 모아졌으며, 그 결과 ISO/IEC MPEG(Moving Picture Experts Group) 및 ITU-T VCEG(Video Coding Experts Group)의 JVT(Joint Video Team)에서는 비디오 부호화의 스케일러빌러티(scalability)를 제공하기 위한 SVC(Scalable Video Coding) 표준화를 진행하였다. 본 논문에서는 공간/시간/화질적 스케일러빌러티를 지원하기 위한 SVC의 대표적 표준 기술들에 대해 설명하고, 기존의 단일 계층(single layer) 부호화 방식과 비교하여 의 부가 비트 요구량 및 부호화 효율에 대해 성능 평가를 하였다. Seamless streaming of multimedia content via heterogeneous networks to viewers using a variety of devices has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is one of attractive features to meet dynamically changing requirements of heterogeneous networks. Currently a new scalable video coding (SVC) is standardizing in the Joint Video Team (JVT) of the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG), which will be released as Extension 3 of H.264/MPEG-4 AVC. In this paper, we introduce new technologies of SVC and evaluate performance of it especially regarding on overhead bit-rate and coding efficiency to support spatial, temporal, and quality scalability.
MPEG-21 및 H.264/AVC SVC 기반 동적 비디오 적응 방법
최해철(Haechul Choi),김재곤(Jae-Gon Kim) 한국콘텐츠학회 2012 한국콘텐츠학회논문지 Vol.12 No.4
근래의 이종 네트워크 환경에서 비디오를 안정되게 전송하기 위해서는 네트워크 특성, 단말기 성능, 사용자 선호도 등의 소비 환경을 고려한 비디오 적응 방법이 요구되며, 비디오 부호화에서의 스케일러빌러티는 그 요구조건을 만족시키기 위한 좋은 해결책이다. 본 논문에서는 H.264/AVC SVC 스트림을 MPEG-21 디지털 아이템 적응(Digital Item Adaptation, DIA) 도구를 이용하여 네트워크 환경, 단말의 성능, 사용자 선호도에 따라 동적(dynamic)으로 비디오 콘텐츠를 적응시키는 방법을 제안한다. 실험에서는 이종망 네트워크 환경을 모델링하여 대역폭이 최대 62%의 변화가 있는 경우에도 제안한 방법으로 지연이 거의 없이 실시간으로 비트율을 적응할 수 있음을 보인다. Seamless streaming of multimedia content that ensures Quality of Service over heterogeneous networks has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is a good feature to meet the requirement of heterogeneous networks. In this paper, we propose a dynamic adaptation scheme of H.264/AVC SVC bit-stream using the MPEG-21 Digital Item Adaptation (DIA) tool. MPEG-21 DIA framework provides systematic solutions in choosing an adaptation operation to given conditions and supports interoperable video adaptation. The experiment results show that the proposed adaptation scheme provides QoS-enabled delivery and consumption of SVC with time-varying constraints of network, terminal, and user preference, in a robust and efficient way. In particular, the proposed adaptation scheme is proved to work well with very low delay under the condition that the variation rate of the given network bandwidth is upto 62%.
Family-wide distribution and recombination of the Wolbachia endosymbiont in Coleopteran insects
Gilsang Jeong,Taehwa Kang,Soojin Hwang,Haechul Park,Youngcheol Choi,Kyoungsang Cho,Wantae Kim,Kwanho Park,Jonggill Kim,Youngbo Lee,Taeman Han,Jiyoung Choi 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10
The Wolbachia bacterium, one of the most prevalent endosymbiotic bacteria, is known to induce reproductive anomalies such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis in various arthropod species. The bacterium is considered to have had huge impacts on hosts' reproductive biology, immunity, evolution, and molecular machineries. Infection surveys on the bacterium have rather been limited to specific taxa that are mainly of economical importance or conducted with randomly collected organisms. Here we investigated infection frequency of Wolbachia in 206 Coleopteran insects collected from Korea. Among them 28 species (13.59%) across families proved to harbor Wolbachia. The phylogenetic trees based on the partial 16s rRNA gene and the partial Wolbachia surface protein (wsp) gene of Wolbachia show that all the Wolbachia strains belong to either Supergroup A or B and Wolbachia evolved independently from its hosts. In addition, the cophylogenetic analysis of the 16s rRNA gene and wsp gene implies that there have been horizontal DNA transfers and recombination events within and between divergent Wolbachia supergroups.
Relative SATD-based Minimum Risk Bayesian Framework for Fast Intra Decision of HEVC
( Daehyeok Gwon ),( Haechul Choi ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.1
High Efficiency Video Coding (HEVC) enables significantly improved compression performance relative to existing standards. However, the advance also requires high computational complexity. To accelerate the intra prediction mode decision, a minimum risk Bayesian classification framework is introduced. The classifier selects a small number of candidate modes to be evaluated by a rate-distortion optimization process using the sum of absolute Hadamard transformed difference (SATD). Moreover, the proposed method provides a loss factor that is a good trade-off model between computational complexity and coding efficiency. Experimental results show that the proposed method achieves a 31.54% average reduction in the encoding run time with a negligible coding loss of 0.93% BD-rate relative to HEVC test model 16.6 for the Intra_Main common test condition.
MPEG-U–based Advanced User Interaction Interface Using Hand Posture Recognition
Gukhee Han,Haechul Choi 대한전자공학회 2016 IEIE Transactions on Smart Processing & Computing Vol.5 No.4
Hand posture recognition is an important technique to enable a natural and familiar interface in the human–computer interaction (HCI) field. This paper introduces a hand posture recognition method using a depth camera. Moreover, the hand posture recognition method is incorporated with the Moving Picture Experts Group Rich Media User Interface (MPEG-U) Advanced User Interaction (AUI) Interface (MPEG-U part 2), which can provide a natural interface on a variety of devices. The proposed method initially detects positions and lengths of all fingers opened, and then recognizes the hand posture from the pose of one or two hands, as well as the number of fingers folded when a user presents a gesture representing a pattern in the AUI data format specified in MPEG-U part 2. The AUI interface represents a user’s hand posture in the compliant MPEG-U schema structure. Experimental results demonstrate the performance of the hand posture recognition system and verified that the AUI interface is compatible with the MPEGU standard.
( Taeman Han ),( Haechul Park ),( Seung-hyun Kim ),( In Gyun Park ),( Deuk-soo Choi ) 한국잠사학회 2018 International Journal of Industrial Entomology Vol.36 No.2
We found the large narcissus fly, Merodon equestris (Fabricius), which has been doubted to occur in Korea. This species is an economically important in management of narcissus and also of quarantine pests. We therefore provide the morphological diagnosis and DNA barcode sequences for rapid species identification of M. equestris based on the five Korean specimens.
Wolbachia infection in the Korean endemic firefly, Luciola unmunsana (Coleoptera: Lampyridae)
Gilsang Jeong,강태화,Haechul Park,,Wontae Kim,Youngcheol Choi,Kyeongyong Lee,Ingyun Park,Hasik Sim,Jonggill Kim 한국응용곤충학회 2009 Journal of Asia-Pacific Entomology Vol.12 No.1
Wolbachia is one of the most prevalent endosymbiontic bacteria of arthropods. The bacterium induces sex ratio distortions in various host insects through processes such as cytoplasmic incompatibility, feminization, male killing, and parthenogenesis. We investigated if the Korean endemic firefly, Luciola unmunsana was infected with the bacterium because the species had an abnormal sex ratio in the field. The results show that some individuals are infected with the bacterium. Phylogenetic analyses showed that the bacterial strain infecting the firefly is closely related to strains that infect phylogenetically distant hosts.