• Journal of Broadcast Engineering
• /
• v.17 no.1
• /
• pp.95-107
• /
• 2012

Network coding was proposed to increase the achievable throughput of multicast in a network. Recently, combining network coding into user cooperation has attracted research attention. For cooperative transmission schemes with network coding, users combine their own and their partners messages by network coding. In previous works, it was shown that adaptive DF with network coding can achieve diversity gain and additional throughput gain. In this paper, to improve performance of conventional protocols and maximize advantage of using network coding, we propose a new network coding based user cooperation scheme which uses adaptively amplify-and-forward and decode-and-forward according to interuser channel status. We derive outage probability bound of proposed scheme and prove that it has full diversity order in the high SNR regime. Moreover, based on the outage bound, we compute optimal power allocation for the proposed scheme.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2005.11a
• /
• pp.531-534
• /
• 2005

한국천문연구원에서는 한국우주전파관측망(Korean VLBI Network: KVN)을 위한 전파영상합성기(상관기) 개발을 진행하고 있다. 전파관측 VLBI 시스템 중 상관기(Correlater) 시스템의 한 구성요소로서 데이터 입력 부분에 각 관측 사이트의 데이터를 사전 처리하는 Station Unit(SU)이 있다. VLBI 시스템에서, 디지털화된 데이터의 다중채널은 테이프 또는 하드디스크에 다중트랙 형태로 인코딩된다. 이 SU의 주요기능은 다중트랙으로부터 인코딩된 데이터를 디코딩하고, 마치 기록되지 않은 것과 같이 채널기반의 샘플 스트림으로 이 데이터를 복원하는 것이다. 이 기능을 원활하게 수행하기 위해서, SU는 논리적으로 재생기 시스템과 함께 시스템이 통합될 필요가 있다. 본 논문에서는 전파 천문 VLBI 시스템 중 SU의 기능과 구조에 대해 고찰하고자 한다.

• Journal of Korea Multimedia Society
• /
• v.3 no.4
• /
• pp.424-432
• /
• 2000

In this paper, we propose a new signaling method and circuits for interface between the host and LCD (Liquid Crystal Display) controller in the LCD system. The proposed circuits are allowed to transmit two data signals through modified-LVDS circuits and can reduce the operating frequency to a half. Then, we can solve EMI(Electro Magnetic Interference) problem and the power consumption by using differential signaling method. We have compared and analyzed the proposed method and the conventional methods in the power consumption and data rate. In addition, the proposed methods reduce hardware complexity significantly.

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.5
• /
• pp.13-21
• /
• 2020

This paper proposes a sign reversal channel switching method in space-frequency block code for orthogonal frequency division multiplexing system. In case of sending source data on other antenna, it is necessary for the receiver to change combining method according to the channel variation. If one does not know the predefined channel switching sequence, it is not possible to decode the received data precisely. In transmit data symbols' exchanges for a channel switching, data symbols are exchanged according to a format of space-frequency block code. In this paper, we proposes a simple sign reversal method except exchanging data symbols between transmit antennas. It is shown that this method occurs another combining method for a simple encryption in the receiver.

• Journal of the Korea Convergence Society
• /
• v.4 no.4
• /
• pp.21-29
• /
• 2013

Two-dimensional QR Code has improved greatly the limits on the capacity, size, direction of the one-dimensional bar code. And it has the capacity of compressing and storing the massive amount of data and is widely used in many applications. Recently, the two-dimensional QR Code has been spread rapidly because of introducing the smart phones and increasing the amount of using them. However, there is little documentations about decoding the QR Code in which can store the large amount of information. In this paper, therefore, we present specific processing procedures and algorithms on decoding the two-dimensional QR Code and then make us understand their decoding process by explaining some examples.

• Journal of KIISE
• /
• v.42 no.1
• /
• pp.130-137
• /
• 2015

With the rapid increase of energy consumption and environmental problems, the need for green techniques is increasing. Network coding can provide a solution by reducing unnecessary data transmission and by estimating traffic patterns. In addition, it can amplify the synergy with the cognitive radio network (CR) since the CR has recognition and optimal decision functionalities. In this paper, we propose a network coding based green cognitive radio network. With the simulations, we show that the proposed scheme is up to 25% better than the previous work.

• Journal of Convergence for Information Technology
• /
• v.9 no.4
• /
• pp.14-20
• /
• 2019

The purpose of this paper is to present a smart QR code recording system and a method of non­storage data delivery that transforms the original data into a form of URL information by encrypting it and encoding the URL information into a QR code so that the QR code can be written and decrypted in a medium without storing the original data. The method of the study was presented by the prior art study and the literature research. Analysis results show that the system is built on the online administration server. The data input signal matching secret code is stored in DB, the QR code generation command converts input data from the password DB to the password information combined into the subordinate locator of the admin server's domain name, URL code. Therefore, the smart QR method of data management (recording and providing) indicates that there are no limitations in the ease and space of use or obstacles to capacity use.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2013.11a
• /
• pp.182-185
• /
• 2013

본 논문에서는 효과적인 홀로그래픽 비디오 서비스를 다양한 재생환경에서 제공하기 위한 스케일러블 코딩 방법을 제안한다. 이 방법은 홀로그램과 광원의 차영상을 사용하여 압축을 하는 방식으로 구성된다. 즉, 기존의 스케일러블 코딩방식인 홀로그램 해상도 스케일러블 코딩과 광원의 화질 스케일러블 코딩 방식을 조합하여 새로운 알고리즘을 제안한다. $1,024{\times}1,024$ 크기의 홀로그램의 차영상에 대해서는 손실압축, 광원의 차영상은 무손실 압축을 이용하여 스케일러블 코딩을 수행함으로써 적응적인 서비스가 가능하도록 한다.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.5 no.1
• /
• pp.1-6
• /
• 2010

본 논문에서는 네트워크 온 칩(NoC: network on chip) 구조에서의 내부 데이터 통신의 성능을 최적화 할 수 있는 새로운 온 칩 네트워크 인터페이스 구조를 제안하였다. 제안하는 NoC 구조는 기본적으로 하드웨어 면적을 줄이기 위하여 XY 라우팅 알고리듬을 기반으로 구현되었으며, 전달되는 패킷의 크기 또는 플릿의 개수를 최소화하기 위하여 Golomb-Rice 인코딩/디코딩 알고리듬에 기반을 둔 하드웨어 압축기/해제기를 이용하여 통신되는 데이터의 양을 크게 줄임으로써 네트워크 지연시간을 최소화 할 수 있는 새로운 구조를 제안하였다. 즉 전송될 데이터는 전송자(sender)의 네트워크 인터페이스에서 내장된 하드웨어 인코더를 통해 압축된 형태로 패킷의 개수를 최소화하여 온 칩 네트워크상의 데이터를 업로드하게 된다. 이러한 압축된 데이터가 리시버(receiver)에 도착하면, 하드웨어 디코더를 통해서 원래의 데이터로 복원된다. 사이클 수준의 시뮬레이터를 통하여 제안된 라우터 구조가 온 칩 시스템의 네트워크 지연시간을 크게 줄일 수 있음을 증명하였다.

• The KIPS Transactions:PartA
• /
• v.16A no.3
• /
• pp.181-188
• /
• 2009

Transcoding is one of core techniques that implement VoD services according to QoS. But it consumes a lot of CPU resource. A transcoding proxy transcodes multimedia objects to meet requirements of various mobile devices and caches them to reuse later. In this paper, we propose a service policy that reduces the load of transcoding multimedia objects by degrading QoS in a transcoding proxy. Due to the tradeoff between QoS and the load of a proxy system, a transcoding proxy provides lower QoS than a client's requirement so that it can accomodate more clients.