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The purpose of this study is to analyze the English learning experience of college students using Colaizzi's method, which is one of the qualitative research methods, using self-coaching technology as a tool to improve self-directed learning ability. In-depth interview were conducted to collect data, and 9 significant statements, 4 theme clusters, and 2 categories were derived.The results are as follows. First, it showed that the participants clearly set the reasons and goals for learning English. Second, it was confirmed that they had time to return to the positive motivation they experienced in the past and strengthened their will to overcome difficulties caused by self-coaching. Third, it was reported that they had a valuable experience of asking the questions presented for the first time, and they recollected the feelings of when they happily learned English, thereby gaining new vitality for learning English. Finally, it also showed that they experienced risk factors such as a desire to procrastinate, a desire to give up, and a rush to complete a task due to difficulty in self-control, which could lead to poor learning.Based on these results, it was suggested that self-coaching contributed to the improvement of learning English, the importance of questions, necessary factors when expanding to regular classes, and the expansion of coaching research.

Whereas the closed-caption broadcasting is provided for almost the whole broadcast time in Korea, the sign language interpretation is not. By translating the realtime closed captions, it is possible to provide three-dimensional (3D) sign language translations for more broadcast time. We propose a sign language broadcasting system for weather forecasts and extend it for all kinds of TV programs. To find the frequency of each word, we analyzed the last three years' weather forecast scripts, and an open-domain corpus of about 1.2 million words from the Korean Broadcasting System. We use KorLex, the Korean wordnet, to build the sign language synonym dictionary and for the word sense disambiguation to improve the translation performance. Optically captured sign language motions are used for the 3D avatar to present sign language with motion blending. We developed a mobile on-demand sign language weather forecast application and a realtime sign language interpretation system for all kinds of TV programs.

Holographic data storage is a strong contender to become the next-generation data storage method. Its major weaknesses are two-dimensional intersymbol interference between neighboring pixels and interpage interference caused by storing multiple pages in a single volume of hologram. In this paper, we present a trellis encoding scheme of 6/8 balanced modulation code, to address the two weaknesses. The proposed modulation coding scheme captures on characteristics of the balanced code: the scheme relaxes IPI and enables error correction by exploiting the trellis structure. The proposed method showed improved SNR over the conventional 6/8 modulation

A holographic data storage (HDS) has some advantages of high storage capacity, fast transmission, and short access time. However, there are two major concerns with the system which are two-dimensional (2D) inter-symbol interference (ISI) and inter-page interference (IPI). Thus, this paper proposes a 4-level 6/9 modulation code which mitigate inter-symbol interference (ISI). ※ 이 논문은 2013년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임 (NRF-2013R1A1A2059077). First Author : Soongsil University, School of Electronic Engineering, kimbs@ssu.ac.kr, 학생회원 ° Corresponding Author : Soongsil University, School of Electronic Engineering, zlee@ssu.ac.kr, 종신회원 * Soongsil University, School of Electronic Engineering, pkhroma@gmail.com 논문번호:KICS2014-09-359, Received September 25, 2014; Revised October 1, 2014; Accepted October 1, 2014. I. 서 론 홀로그래픽 데이터 저장시스템 (holographic data storage system, HDS)은 표면에 정보를 저장하는 광 기록 저장장치(CD, DVD, BD)나 자기기록 저장 장치 (hard disk drive, HDD)와는 다르게 매질의 체적에 데 이터를 저장하기 때문에 저장용량을 현저히 증가시킬 수 있다. 이 때문에 근접장 기록(near field recording, NFR)이나 SUPER_RENS (Super REsolusion Near-Field Structure)와 함께 차세대 광기록 저장장치 로 연구되고 있다. HDS는 기록과 재생이 페이지 단위 로 이루어지므로 한 페이지가 가지는 총 비트 수와 다 중화된 홀로그램 수의 곱으로 저장 매질의 총 저장용 량이 결정된다. 입력 데이터가 홀로그램의 체적 내에 서 2차원 페이지의 단위로 기록하고 읽기 때문에 저 장용량을 크게 증가시킬 수 있다. (즉, 데이터 저장용 량은 한 공간에 많은 페이지를 저장하면 할수록, 그리 고 한 페이지에 많은 데이터를 저장하면 할수록 증가 한다.) 또한 2차원 페이지 단위로 신호처리가 가능하 기 때문에 데이터 전송속도 또한 매우 증가시킬 수 있 다. 기존의 데이터 저장장치와 같이 표면에 정보를 저 장하는 데이터 저장장치에서 주로 오류를 범하게 하는 요인이 인접심볼간 간섭 (inter-symbol interference, ISI)이라면 HDS는 페이지 단위로 매질의 체적에 겹 쳐 쓰면서 저장하기 때문에 인접 페이지간 간섭 (inter-page interference, IPI)이 존재한다 . 그리고 논문 / 홀로그래픽 데이터 저장장치를 위한 4레벨 6/9 변조부호 575 Fig. 1. Examples of severe ISI in four-level HDS Fig. 2. Structure of a codeword in the proposed modulation code Fig. 3. Example of codewords Fig. 4. Structure of encoding scheme. Table 1. Symbol mapping rule 페이지 단위로 데이터를 쓰고 읽기 때문에 ISI가 2차 원으로 영향을 준다. 이진 픽셀의 경우 가장 큰 ISI를 일으키는 상황은 0 (혹은 1) 픽셀이 1 (혹은 0) 픽셀들 로 둘러싸인 경우와 같은 고립된 픽셀 패턴(isolated pixel patterns)이다 . HDS가 멀티레벨인 경우는 최하위 레벨과 최상위 레벨이 인접한 경우 최상위 레 벨의 심볼이 최하위 레벨의 심볼에게 심한 간섭을 일 으키게 된다. 따라서 멜티레벨의 경우에 ISI를 줄이기 위해서는 최상위 레벨 심볼과 최하위 레벨 심볼이 인 접하지 않게 하여야 한다. 그림 1은 4-레벨 심볼인 경 우, 0 픽셀과 3 픽셀이 인접하여 이웃한 픽셀에 큰 ISI 를 발생하는 예이다. 본 논문에서는 그림 1과 같이 레벨 0 심볼과 레벨 3 심볼이 인접하는 상황이 발생하지 않도록 하기 위 한 변조부호를 제안하였다. II장에서는 본 논문에서 제안된 4-레벨 6/9 변조부호에 대하여 설명한다. III장 에서는 시뮬레이션 환경 및 결과를 보여주고, 마지막 IV장에서는 앞 장의 결과를 바탕으로 결론을 내린다. II. 제안된 4-레벨 6/9 변조부호 한 픽셀이 가질 수 있는 심볼의 종류가 4-레벨이므 로 입력되는 두 비트 (예: 00, 01, 10, 11)를 하나의 심 볼로 만든다. 그림 2는 3⨯3 배열의 코드워드 구조와 제안된 변조부호의 구성 방법을 보여준다. 6개의 심볼 데이터가 입력되어 9개의 심볼 데이터로 3⨯3 배열의 형태로 출력되게 되며, 한 코드워드는 두 부분으로 나 뉘어져 있다. (a, e, i) 위치의 픽셀들은 {0, 1, 2, 3} 레벨의 심볼이 올 수 있다. 나머지 픽셀들은 {1, 2} 레 벨의 심볼만 가능하다. 이렇게 하면 인접한 픽셀이 그 림 1과 같이 0 심볼과 3 심볼이 이웃하는 경우가 생기 지 않게 된다. 그림 3은 두 코드워드를 연결하였을 때, 제안된 변 조부호로 이루어진 코드워드가 인접한 어느 심볼도 레벨 0과 레벨 3이 인접하지 않는 것을 확인할 수 있 다. 이로 인해 제안된 변조부호는 2D-ISI를 완화할 수 있다. 제안된 변조부호의 코드율은 0.667(=6/9)이며 픽셀당 4/3비트를 기록한다. 6 심볼 (12 비트)의 입력 데이터는 그림 4와 같이 9 픽셀의 출력 코드워드로 변조된다. 먼저, a0, a1, a2 는 B0, B4, B8에 각각 순서대로 1-1 대응되고, 표 1에 있는 매핑 규칙에 따라 a3은 B1과 B3 픽셀에 해당하는 심볼들을 할당하고, a4는 B2와 B6에, a5는 B5와 B7에 각각 표 1과 같이 각 픽셀의 심볼값이 정해진다. 복조 과정은 데이터 변조 과정이 1:1 맵핑 방식이므로 변조 과정의 역순으로 진행된다.

In order to improve the storage density of magnetic recording, the shingled magnetic recording method is used. However, this method have a problem of interference between adjacent tracks. Therefore, many studies to prevent the performance degradation due to interference between the adjacent track have been conducted. In this paper, in order to solve inter-track interference, we propose a model to remove inter-track interference. In the case of overlap between tracks is 10% or more, the proposed model shows the performance improvement. ※ 이 논문은 2013년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임(NRF-2013R1A1A2059077). First Author : Soongsil University, School of Electronic Engineering, kimbs@ssu.ac.kr, 학생회원 ° Corresponding Author : Soongsil University, School of Electronic Engineering, zlee@ssu.ac.kr, 종신회원 논문번호:KICS2014-08-325, Received August 27, 2014; Revised September 4, 2014; Accepted September 4, 2014 I. 서 론 수직 자기기록 방식의 하드디스크는 동심원 상에 위치한 트랙을 따라 기록 매질이 덮여 있어 기록 매질 에 데이터를 저장하는 방식이다. 이러한 하드디스크의 성능을 향상시키기 위해선 단위 면적당 기록 밀도를 높여야 하는데 트랙 안에서 밀도를 높이는 방법은 이 미 한계에 도달했다. 그래서 대안으로 트랙간의 간격 을 줄여 인치당 트랙의 양을 늘리는 방법이 연구되었 다. 오늘날에는 더 나아가 인접한 트랙을 서로 겹쳐서 쓰는 SMR (Shingled Magnetic Recording) 방식이 연 구되고 있다. 그림 1은 SMR 방식의 모형으로, N-1번 째 트랙에 데이터가 입력 된 후, N번째 트랙이 SW(Squeeze Width)만큼 겹쳐진다. 그리고 N번째 트 랙에 데이터가 입력된 후 마찬가지로 N+1번째 트랙 이 SW만큼 겹쳐지는 방식이다. 본 논문에서 SW는 α 로 표현하였다. 그림 1에서 WTW(Write Track Width)는 전체 트랙의 폭이고, TW(Track Width)는 실제적인 트랙의 폭이 된다. α값이 커질수록 인치당 트랙의 양은 늘어나 더 많은 데이터를 저장 할 수 있 논문 / 인접 트랙간 간섭 제거기를 이용한 트랙을 겹쳐서 쓰는 자기기록 방식의 성능 개선 509 Fig. 1. Shingled Magnetic Recording 게 되지만, 인접한 트랙간 간섭 (Inter-Track Interference, ITI)은 더욱 심각해진다. SMR 방식이 기존의 기술에서 큰 변화 없이 기록 밀도를 높일 수 있어 주목을 받으면서, SMR 방식의 가장 큰 문제점인 ITI를 완화시키기 위한 많은 연구가 진행되어왔다. 한 방법은 ITI를 독립적인 데이터에서 발생하는 하나의 신호나 잡음으로 간주하는 방법이다. 이 경우에는 최대 유사도 방법 (Maximum-Likelihood, ML)으로 검출이 가능하지만, 복합적인 원래의 신호에 서 ITI를 분리해내기 쉽지 않아 최종 비트 오율 (Bit Error Rate, BER)이 좋지 못한 단점이 있다. 또 다른 방법은 single-head/successive-multi-track 신호 검출 방법으로, 완벽하게 복원된 데이터나 LLRs (LogLikelihood Ratios)와 같은 주변 정보를 이용하는 방 법이다 . 하지만 ITI의 영향을 받지 않은 트랙으 로부터 주변정보를 얻어야 하기 때문에 목적지 트랙 까지의 접속 처리량이 크게 감소하는 단점이 있다. 본 논문에서는 ITI를 제거하기 위해 ITI를 하나의 잡음으 로 보고 인접한 트랙간 간섭을 제거하는 모델을 제시 하였다. 본 논문의 II장에서는 ITI의 채널 모델과 ITI 제거 기 모델에 대해 살펴보고, III장에서는 제시된 모델의 성능을 비교해 보기 위한 다양한 시뮬레이션 결과를 살펴본다. 마지막으로 IV장에서는 본 논문의 결론을 정리한다. II. 인접한 트랙간 간섭 제거 모델 2.1 ITI 채널 모델링 트랙에 데이터를 읽고/쓰는 과정에서 현재의 트랙 과 인접한 트랙간의 위상이 어긋나는 경우가 발생할 수 있다. 따라서 ITI를 제거하기에 앞서 상관관계 (Correlation) 방법을 이용하여 인접한 트랙간의 어긋 난 위상을 검출해야 한다. N번째 트랙의 이퀄라이저 출력  는 다음과 같다.                                  (1) 식 (1)에서  ,  ,  은 길이가 각각 2L+1인 N-1번째, N번째, N+1번째의 이퀄라이저 채 널 응답을 의미한다. 그리고  과  은 각 각 N-1번째와 N+1번째 트랙의 N번째 트랙과의 상대 적인 위상차이다.  은 N번째 트랙에 기록된 비트 시퀀스이고,  은 N번째 트랙의 잡음으로 평균이 영이고 스펙트럼이 상수인 백색잡음으로 가정한다. 그 리고 N-1번째와 N+1번째 트랙의 비트 시퀀스   과  은 알고 있다고 가정하였다. ITI가 완전히 제거된 최종 출력의 모양은 다음과 같다.            (2) 위상차가 없다는 가정에서, N-1번째 트랙의 비트 시퀀스가 N번째 트랙에 미치는 correlation metric은 다음과 같다.                                      (3)                      

The shingled magnetic recording method has interference between adjacent tracks. Furthermore, when read-head reads the data along the track, the head can be skewed by some physical effects. In this paper, in order to solve this problem, we propose a two-dimensional equalizer that uses two heads. If the head is skewed, it is possible to complement the performance by positioning the two heads at the center of the current track. ※ 이 논문은 2013년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임(NRF-2013R1A1A2059077). First Author : Soongsil University, School of Electronic Engineering, kimbs@ssu.ac.kr, 학생회원 ° Corresponding Author : Soongsil University, School of Electronic Engineering, zlee@ssu.ac.kr, 종신회원 논문번호:KICS2014-08-326, Received August 27, 2014; Revised September 4, 2014; Accepted September 4, 2014 I. 서 론 자기기록 저장 장치의 저장 밀도 향상을 위해 수평 자기기록 방식에서 수직 자기기록 방식으로 변화되었 다. 하지만 수직 자기기록 저장장치 역시 초성자성 현 상에 의한 밀도 증가의 한계에 도달하였다. 이러한 트 랙 내에서의 기록 밀도 향상의 한계를 극복하기 위해 트랙간의 간격을 줄이는 방법이 연구되어왔고, 근래에 는 트랙과 트랙을 겹쳐서 쓰는 SMR (Shingled Magnetic Recording) 방식이 연구되어왔다. SMR 방 식은 이전 트랙의 일부분에 새로 쓰이는 트랙이 일부 겹쳐지는 방식으로 겹쳐지는 양 만큼 이전 트랙의 폭 이 원래의 트랙 폭 보다 실질적으로 좁아지는 결과를 가져오게 된다. 따라서 전체적인 기록밀도의 향상을 얻을 수 있게 된다. 하지만 트랙간의 간격이 좁아짐에 따라 인접 신호간 간섭 (Inter-Symbol Interference, ISI)과 함께 인접 트랙간 간섭 (Inter-Track Interference, ITI) 역시 심각한 문제가 되었다 . 자기기록 장치에서 리드헤드가 트랙을 따라 돌면서 데이터를 읽을 때, 물리적인 영향으로 리드헤드가 방 향이 틀어 질 수 있다 . 그림 1은 이러한 경우를 그림으로 나타냈다. 그림 1의 첫 번째 그림과 세 번째 논문 / 트랙을 겹쳐서 쓰는 자기기록 방식에서 리드헤드가 틀어진 경우의 성능 분석 515 Fig. 1. Three types of skewed head Fig. 2. Block diagram of two-dimensional equalizer 그림은 각각 리드헤드가 음(-)의 방향과, 양(+)의 방향 으로 틀어진 경우이고, 두 번째 그림은 리드헤드의 틀 어짐이 없이 정상적으로 데이터를 읽어 들이는 경우 이다. 리드헤드가 음 또는 양의 방향으로 틀어진 경우 그림과 같이 인접한 트랙으로 부터의 간섭이 더 심해 져 성능이 열화된다. 본 논문에서는 SMR 방식에서의 ITI 문제와 리드 헤드의 틀어짐에 따른 성능 문제를 해결하기 위해 두 개의 리드헤드를 사용하는 이차원 이퀄라이저를 제안 하였다. II장에서는 본 논문에서 제안된 이차원 이퀄 라이저의 알고리즘에 대해서 설명한다. III장에서는 시 뮬레이션 환경 및 결과를 보여주고, 마지막 IV장에서 는 앞 장의 결과로 결론을 내린다.

In this paper, we introduce a 2-D non-isolated pixel modulation code to mitigate the problem of 2-D inter-symbol interference, the major obstacle of holographic data storage systems. The proposed modulation code does not allow a pixel to be isolated from its adjacent bits. We compare the bit error rate (BER) performance between the proposed and the conventional 6/8 balanced modulation codes. The proposed code shows better BER performance than that of the conventional 6/8 balanced code in a poor channel environment, such as large blur and misalignments.

In holographic data storage (HDS), a high transmission rate is accomplished through the use of a charge coupled device array for reading two-dimensional (2D) pixel image data. Although HDS has many advantages in terms of storage capacity and data transmission rates, it also features problems, such as 2D intersymbol interference (ISI) by neighboring pixels and interpage interference (IPI) by multiple images stored in the same holographic volume. Modulation codes can be used to remove these problems. We introduce a 2D 8/9 error-correcting modulation code. The proposed modulation code exploits the trellis-coded modulation scheme, and the code rate is larger (about 0.889) than that of the conventional 6/8 balanced modulation code (an increase of approximately 13.9%). The performance of the bit error rate (BER) with the proposed scheme was improved compared with that of the 6/8 balanced modulation code and the simple 8/9 code without the trellis scheme.

Holographic data storage (HDS) has a number of advantages, including a high transmission rate through the use of a charge coupled device array for reading two-dimensional (2D) pixel image data, and a high density capacity. HDS also has disadvantages, including 2d intersymbol interference by neighboring pixels and interpage interference by multiple pages stored in the same holographic volume. These problems can be eliminated by modulation codes. We propose a 7/9 error-correcting modulation code that exploits a Viterbi?trellis algorithm and has a code rate larger (about 0.778) than that of the conventional 6/8 balanced modulation code. We show improved performance of the bit error rate with the proposed scheme compared to that of the simple 7/9 code without the trellis scheme and the 6/8 balanced modulation code.

Recently, 3DTV has drawn much attention as a new broadcasting service. In spite of technical advances in 3DTV broadcasting services, there are two barriers that hinder the new services from being launched for terrestrial broadcasting: the lack of available bandwidth for transmission of additional-view video via terrestrial channel and backward compatibility with the legacy 2-D HDTV services. As an alternative, a hybrid stereoscopic video coding scheme is proposed for a stereoscopic 3DTV service, where one-view video is transmitted through the legacy broadcasting systems and the other one is delivered via broadband networks to which TV terminals are connected. In this paper, the proposed hybrid stereoscopic video coding scheme incorporates an MPEG-2 codec for backward compatibility with a legacy 2-D HDTV service and an HEVC codec with inter-view prediction coding as an extension to encode additional-view video sequences with high coding efficiency. The proposed inter-view prediction coding scheme in the extended HEVC incorporates an advanced motion and disparity vector prediction (AMDVP) method for enhanced motion- and disparity-compensated coding. The experimental results demonstrate that the proposed hybrid stereoscopic video coding scheme achieves an average coding efficiency of 38.22% (32.86%) in BD-rate or 1.394 dB (1.235 dB) in BD-PSNR for the out-band (in-band) scenario.

9: ; 6MHz:/?@AB C!1D:MPEG-2 HD ";EF3D:H.264/AVC SD ";E, G4D: A >!"# . HIJKoreaView>K-L>3D:SDM";E N0 O PFQ0RS"TUV=W X YZ[0\]^_P` a >bcA- d . eZ !> IWKoreaView:W cAfg W #hiIj";E !"#$%&'(` kW . k > !"#$%&'(>H.264/AVC SD ";E3D`H.264/SVC e l `mOni o!"# , p l VK-q3D:HD ";E`r/?sAmOt u : A!"#`-+ oW . v 9:3D:SD Z p lAK-wxVt C AmO[0\]^_P`y>uID: Az{ oq . k >$%&'(:*+A|} u~ VZ !€L> W‚ A € u~ƒA„ † . ‡ˆH.264/SVC` € uSD ‰Š";E- e lZ!1.5Mbps RS"TUV ‹Y, 34.5-42.9dB: A u €!"#--+W„Œ:Žw A „dAz=„d‘ . ’W12Mbps RS"TUV qMPEG-2 HD g“‚ ” k >!"#$%&'(:H.264/SVC p l:HD g“‚ A"• u *+A–— † . MPEG-2 HD g“‚ ”BWŽw „ŒA u k >!"#$%&'(Z!€qH.264/SVC `„ W˜”~ƒ‚ :™šF›*Zœž690kbpsZ!8,200kbps:"TU Ÿ 6A~ƒAm uz= † .AbstractOne of the existing terrestrial multi-channel DTV service frameworks, called KoreaView, provides four programs, composed of MPEG-2 based one HD video and H.264/AVC based three SD videos within one single 6MHz frequency bandwidth. However the additional 3 SD videos can not provide enough quality due to its reduced spatial resolution and low target bitrates. In this paper, we propose a framework, which is called a terrestrial multi-channel high quality hybrid DTV service, to overcome such a weakness of KoreaView services. In the proposed framework, the three additional SD videos are encoded based on an H.264/SVC Spatial Base layer, which is compliant with H.264/AVC, and are delivered via broadcasting networks. On the other hand, and the corresponding i¢(Regular Paper) 17 4 , 2012 7(JBE Vol. 17, No. 4, July 2012)http://dx.doi.org/10.5909/JBE.2012.17.4.640

This paper investigates how authentic listening texts affect a whole group or different levels of listeners and verifies how task sequence actually influences task difficulty. For this, three authentic texts, animation, TV news, and Internet video clip, are used and three sets of tasks using text are developed based on ‘function-response matrix for listening activities’. The test result shows that animation, the easiest text of the three, may be usable for most listeners with different listening skills. TV news or Internet video clip may be acceptable only for learners with higher listening proficiency. Task analysis shows that task difficulty or task sequence may vary depending upon texts. Finding particular information in an animation is a relatively easy task while the task of describing the main storyline in Korean is shown to be more demanding. On the other hand, the task of completing a main idea of TV news and video clip is the most appealing for listeners, and the task requiring listeners to duplicate what they hear has higher task difficulty. Task difficulty is subject to change depending on both listening texts and tasks. Thus, teachers first have to recognize specific properties of authentic texts and listening tasks, and select texts and design tasks, considering a learner’s listening proficiency and classroom instructional purpose.

In this paper, a fast intermode decision scheme is introduced by efficiently performing the mode decision using statistical hypothesis testing for hierarchical B-picture coding of SVC, in which much computational power is expensed for combined variable block sizes and hierarchical B-pictures. The hypothesis testing in the proposed method is performed on blocks to have early termination for RD computation of all possible modes. The early termination in intermode decision is performed by comparing the pixel values of current blocks and corresponding motion-compensated blocks. The proposed scheme exhibits effective early termination behavior in intermode decision and leads to a significant reduction up to 69% in computational complexity with slight increment in bit amounts. The degradation of visual quality turns out to be negligible in terms of PSNR values.

In this study, an investigation for the degradation of p+ to p+ isolation characteristics in a high voltage process with shallow trench isolation was carried out. It could be explained that the degradation phenomenon was caused by carrier injection. In order to improve this, the results of p+ to p+ isolation degradation were determined under different ion implantation conditions and depths and widths of isolation. From these results, it was found that carrier injection mainly occurred at the sidewall of a trench, and the interface trap between Si3N4 and SiO2 was considered to be a dominant factor based on the result of degradation reduction with increasing thickness of sidewall oxide. Consequently, the improvement of the p+ to p+ isolation degradation caused by carrier injection could be achieved by optimizing the dose of a masked lightly doped drain and a field implantation energy.

The sense of presence in UHDTV(Ultra High Definition TV) mainly arises from a wide field of view combined with ultra high definition resolution and an extremely fine picture quality. Therefore, UHDTV requires a resolution of 4K(3840x2160) or 8K(7680x4320) pixels. Furthermore, to provide a more vivid picture, UHDTV goes as far as a frame-rate of 120fps, a wider colour gamut and a colour-depth of 12 bits. For this reason, UHDTV necessarily results in an extremely huge amount of data. Even many experts have questioned whether the 6MHz or 8MHz bandwidth of a terrestrial TV channel offers realistic possibilities for UHDTV transmission. In Korea, the KBS(Korean Broadcasting System) carried out the world's first terrestrial 4K 30p UHDTV experimental broadcast from 9th October to 31st December 2012. The most prominent feature of this broadcasting was the use of a terrestrial TV channel. To fit the extremely high video datarate into its limited bandwidth, we exploited HEVC (High Efficiency Video Coding) compression and DVB-T2 transmission and reception systems. In this paper, we shall give an overview of KBS' 4K-UHDTV experimental broadcast and explain 4K-UHDTV content compression with an HEVC codec and the DVB-T2 system used in the trial. In addition, we shall show the result of our optimisation tests on HEVC coding of 4K 60p UHDTV.

New broadcasting services such as 3DTV and UHDTV are turning up and catching the public attention, because people nowadays like to have more realistic watching experience in TV. However, terrestrial broadcasters have difficulties in launching them, because new terrestrial broadcasting services necessarily need new frequency allocation. As frequency is public goods and the frequency for broadcasting is limited. To solve the lack of frequency, we designed hybrid 3DTV broadcasting technology combining terrestrial broadcasting channel and broadband network. For the hybrid 3DTV, the left view is transmitted through the terrestrial broadcasting channel and the right view is delivered using the internet. The difference of two transport networks causes inevitable receiving time delay. To synchronize the left view and the delayed right view by frame accuracy, we insert SMPTE time code into the left and right elementary streams respectively and transmit them. To verify the validity and practicality of hybrid 3DTV service, we performed live broadcasting of ‘IAAF World Championships’ in August 2011 via hybrid 3DTV technology.

A hybrid stereoscopic broadcasting service is considered a possible solution to the lack of frequency bandwidth for transmission of additional view sequences and to the backward compatibility for the existing MPEG-2 based DTV services. In this paper, a hybrid stereoscopic encoder based on MPEG-2 and HEVC is first considered where left-view sequences are encoded by MPEG-2 to provide the backward compatibility while right-view sequences are encoded by HEVC for delivery over Internet. In the hybrid stereoscopic encoder, we propose an inter-view coding scheme between the left- and right-view sequences to enhance the coding performance of HEVC for right-view sequences. Therefore, in this paper, an extension to HEVC is made with an inter-view coding scheme by having disparity based motion-compensated prediction. For this, MPEG-2 motion vectors from left-view sequences and global disparity vectors between two-view sequences are utilized. The experimental results show that the proposed hybrid stereoscopic encoder achieves average 37.75% coding gain in BDBR compared with the performance of HEVC simulcast encoding for right-view sequences.

Quantization in video coding plays an important role in controlling the bitrate of compressed bitstreams to adjust with the allowed bandwidth of delivery networks and storage. Since scalable video coding (SVC) being currently standardized exhibits highly dependent coding nature not only between frames but also in the lower and higher layers, we propose a dependent quantization scheme for SVC and compare its performance in visual qualities and bitrates with the current technique in JSVM reference software. The experimental results show that the dependent quantization outperforms the current technique in JSVM reference software with 0.5 ~ 1.25 dB PSNR increment or 5 ~ 20% bits saving for the enhancement layer of SVC.

For video streaming, we must consider terminal and network characteristics. The scalable video coding (SVC) can represent video bitstreams in different scalable layers for flexible adaptation to terminal and network characteristics. The SVC can allow for extraction of appropriate partial bitstreams to meet specific target bitrates and spatial resolutions from an SVC bitstream with several spatial, temporal and quality scalability layers. Moreover, the extraction process is fast, so it is possible to extract the partial video streams online to cope with the delivery networks with changing characteristics such as bandwidth etc. With all the advantages of SVC, we design and implement a network-adaptive SVC streaming system to extract partial SVC bitstreams to meet the required target bitrates and spatial resolutions. We present the implementation of our SVC streaming system with experimental results.

We have developed the first bi-directional ONT transceiver module having 10Gbit/s-Rx and 1.25Gbit/s-Tx for asymmetric high-speed TDM-PON, and have confirmed the 10Gbit/s downstream performance with the bi-directional transmission to support 128-way split and 10km reach.

A holographic data storage (HDS) system can provide high storage capacity, faster transmission, and shorter access time. However, there are two major concerns with such systems: two-dimensional (2D) inter-symbol interference (ISI) and inter-page interference (IPI). The use of existing partial response maximum likelihood (PRML) detection can somewhat mitigate the problem of ISI. However, if the channel is subject to misalignment, the performance of PRML detection can be degraded. This problem can be remedied by a modulation code. Thus, this paper proposes a 6/9 modulation code, which mitigates ISI, and a modulation/demodulation scheme.