• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2003.11a
• /
• pp.7-10
• /
• 2003

인터프레임 웨이블렛 부호화(Interframe Wavelet Coding)는 3D 서브밴드(Subband) 부호화라고도 하며, 기존의 DCT기반 Hybrid 동영상 부호화 방식에 비해 압축 효율이 우수하고. 특히 스케일러빌리티 기능이 뛰어난 부호화 방법이다. 인터프레임 웨이블렛 부호화 방법에서 복호화 과정 중 가장 연산 량이 많이 요구되는 역(inverse) 웨이블렛 변환이다 역 웨이블렛 변환의 연산 량은 복호화 과정에서 적용된 웨이블렛 변환과 동일한 연산량을 요구한다. 이는 순방향과 역방향에서 동일 길이의 필터와 분해 레벨을 사용해야 하기 때문이다. 이 웨이블렛 변환의 연산 량을 줄이기 위해 본 논문에서는 기존의 시간 밴드 영상에 대해 동일 한 웨이블렛 필터를 사용하여 공간 웨이블렛 필터를 적용하던 것을. 로우밴드에는 9/7 필터를 적용하고 하이 밴드에는 Haar필터를 사용하는 방법을 제안한다. PSNR 실험에서 기존의 9/7 필터만을 사용하는 경우와 비교한 결과 거의 차이가 없었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2022.06a
• /
• pp.164-166
• /
• 2022

본 논문에서는 ATSC 3.0 Layered-Division-Multiplexing(LDM) Multiple-Inputs-Multiple-Outputs(MIMO) 방송 시스템에서 Core-Layer 신호에 대한 새로운 Hybrid PGA(HPGA) 복호 기법을 제안하고자 한다. 제안된 기법은 각 수신단의 Enhanced-Layer 신호의 평균전력 대비 잡음 값에 따라 기존의 GA 기법과 PGA 기법을 선택적으로 적용하여 기존의 PGA 기법에 비해 큰 성능저하 없이 복호 복잡도는 약 25% 줄일 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2020.07a
• /
• pp.62-65
• /
• 2020

본 논문에서는 ATSC3.0 Layered-Division-Multiplexing Multiple-Inputs-Multiple-Outputs 방송 시스템에서 Core-Layer(CL) 신호 복조 시 기존 Gaussian-Approximation(GA) 기법과 Partial-GA(PGA) 기법을 선택적으로 사용하여 PGA 기법과 성능은 거의 동일하며 복잡도는 더 작은 새로운 Hybrid PGA(HPGA) 복조 기법을 제안하고자 한다. 제안된 복조 기법은 수신단 신호의 Injection Level(IL) 값이 송신 IL보다 높아 CL 신호 입장에서 채널 상태가 좋을 경우 GA 기법을 사용하고, 반대로 수신단 IL 값이 송신 IL보다 낮아 채널 상태나 좋지 않을 경우 성능을 우선한 PGA 기법을 사용하게 된다. 실험 결과 성능은 PGA 기법과 거의 동일하고 복잡도는 PGA 기법의 복잡도 대비 약 25% 정도 작아짐을 보인다.

• Journal of Broadcast Engineering
• /
• v.20 no.1
• /
• pp.68-81
• /
• 2015

Owing to the latest development of component and media processing technologies, UHDTV as a successor of the HDTV is expected that this will be coming soon realization. Accordingly, an audio technology that provides a 5.1-channel surround sound in home should be contemplating on what services should be provided with the advent of UHDTV era. In fact, however, the market of 5.1-channel audio is struggling, due to the difficulty of installation and maintenance of the multi speakers in a home. Meanwhile, the movie sound market for a long time been used in 5.1 and 7.1-channel sound formats, have changed as Dolby ATMOS, IOSONO, AURO3D etc. are launched one after another with the introduction of hybrid audio technologies that include the ceiling and object-based sounds. This very object-based audio technology is assured to be introduced in the home theater and broadcast audio market, and this change in audio technology is expected to be a breath of pioneering technological advances and market growth from the channel-based audio market that lacks flexibility. In this paper, we will investigate a suitable realistic audio solution for UHDTV, and introduce hybrid audio technologies, which is expected to be an audio technology for UHDTV, and we will describe the hybrid audio content format and reproduction methods in a home and consider the future prospects of realistic audio.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.9 s.351
• /
• pp.31-37
• /
• 2006

Low-density parity-check (LDPC) codes are recently emerged due to its excellent performance. The standard for European high definition satellite digital video broadcast, DVB-S2 has adopted LDPC codes as a channel coding scheme. This paper proposes a DVB-S2 LDPC decoder architecture using a hybrid parity check matrix which is efficient in hardware implementation for both decoders and encoders. The hybrid H-matrices are constructed so that both the semi-random technique and the partly parallel structure can be applied to design encoders and decoders. Using the hybrid H-matrix scheme, the architecture of LDPC decoder for DVB-S2 can be very practical and efficient. In addition, we show a new Variable Node processor Unit (VNU) architecture to reuse the VNU for various code rates and optimized block memory placement to reuse. We design a DVB-S2 LDPC decoder of code rate 1/2 usng the proposed architecture. We estimate the performance of the DVB-S2 LDPC decoder and compare it with other decoders.

• Proceedings of the KAIS Fall Conference
• /
• 2008.05a
• /
• pp.192-195
• /
• 2008

Robust control for DC motor is needed according to the highest precision of industrial automation. However, when a motor control system with PID controller has an effect of load disturbance, it is very difficult to guarantee the robustness of control system. In this paper, PID-Expert hybrid control method for motor control system as a compensation method solving this problem is presented. If PID control system is stable, the Expert controller is idle. if the error hits the boundary of the constraint, the Expert controller begins operation to force the error back to the constraint set. The disturbance effect decrease remarkably, robust speed control of DC motor using PID-Expert Hybrid controller is demonstrated by the simulation.

• International journal of advanced smart convergence
• /
• v.12 no.1
• /
• pp.1-8
• /
• 2023

Smart IoT over high speed network and high performance smart devices explodes the ubiquitous services and applications. Nearest Neighbor(NN) query is one of the important type of queries that have to be supported for ubiquitous information services. In order to process efficiently NN queries in the wireless broadcast environment, it is important that the clients determine quickly the search space and filter out NN from the candidates containing the search space. In this paper, we propose a hybrid index of Voronoi and grid partition to provide quick search space decision and rapid filtering out NN from the candidates. Grid partition plays the role of helping quick search space decision and Voronoi partition providing the rapid filtering. We show the effectiveness of the proposed index by comparing the existing indexing schemes in the access time and tuning time. The evaluation shows the proposed index scheme makes the two performance parameters improved than the existing schemes.

• Broadcasting and Media Magazine
• /
• v.19 no.3
• /
• pp.30-45
• /
• 2014

증강현실 기술을 방송에 접목한 증강방송 기술은 최근 스마트TV와 초고속 네트워크를 기반으로 하는 하이브리드 방송 서비스가 활발히 연구되면서 주목받고 있는 기술이다. 본 논문에서는 증강방송 기술의 소개와 현재 서비스되고 있는 증강방송의 기술 동향을 알아보고, 가까운 미래에 나타날 증강방송의 유형을 제안해본다. 또한 현재 ETRI에서 개발되고 있는 스마트TV 기반 양방향 증강방송 기술에서 고려하고 있는 서비스 시나리오들과 이를 제공하기 위하여 구현된 시스템에 대하여 설명한다.

• Journal of KIISE:Information Networking
• /
• v.30 no.2
• /
• pp.155-166
• /
• 2003

Mobile computing becomes a new issue of researches in computing due to the advances of mobile equipment and the connection with Internet. In mobile environment, there are many constraints such as limited bandwidth, intermittent disconnection, limited battery life, and so on. By these reasons, broadcasting has been generally used to disseminate data efficiently by the mobile applications. This paper proposes an adaptive broadcasting method which logically divides broadcast channel into the periodic broadcast channel and the on-demand broadcast channel and dynamically assigns the bandwidths of both channel. The former disseminates data that are selected based on both the popularity and the size of each datum, the latter disseminates data that are selected based on the requests of mobile clients. When selecting data to be disseminated, the proposed broadcasting method considers the mobility of a mobile client and also considers the size of each datum by using SF(size factor) proposed in this paper. This paper also evaluates the proposed broadcasting method by measuring the energy expenditure of mobile client in experiments.

• Journal of KIISE:Information Networking
• /
• v.33 no.4
• /
• pp.333-342
• /
• 2006

The cdma2000 lxEV - DO mobile communication system provides broadcast and multicast services (BCMCS) to meet an increasing demand from multimedia data services. The servicing of video streams over a BCMCS network must, however, face a challenge from the unreliable and error-prone nature of the radio channel. The BCMCS network uses Reed-Solomon coding integrated with the MAC protocol for error recovery. We analyze this coding technique and show that it is not effective in the case of slowly moving mobiles. To improve the playback quality of an MPEG-4 FGS video stream, we propose the Hybrid error recovery scheme, which combines Reed-Solomon with ARQ, using slots which are saved by reducing the Reed-Solomon coding overhead. The target packets to be retransmitted are prioritized by a utility function to reduce the packet error rate in the application layer within a fixed retransmission budget. This is achieved by considering of the map of the error control block at each mobile node. The proposed Hybrid error recovery scheme also uses the characteristics of MPEG-4 FGS (fine granularity scalability) to improve the video quality even when conditions are adverse: slow-moving nodes and a high error rate in the physical channel.