• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.8
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• pp.1-10
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• 2001

This paper describes new line code algorithm, called NIDI(Nibble Inversion mock Inversion) which is well suited for interconnection and transmission technology, The proposed line code which includes only one redundancy bit serves primary features of line code and synchronization patterns for byte or frame synchronization in interconnection, Also, this line code provides in-band signals and speciaI characters.

• Proceedings of the KAIS Fall Conference
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• 2004.11a
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• pp.206-209
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• 2004

Pentium4의 가장 큰 특징은 병렬처리의 최적화이다. 인텔사의 최신 마이크로 프로세서 Pentium4에 적용된 기술들은 SSE2, Intel NetBurst Micro-Architecture, Hyper-Threading Technology 등이다. CPU 속도의 향상 기법은 크게 클럭 속도의 증가, IPC의 증가, 파이프 라이닝의 길이를 길게 하고, 트랜지스터 집적도를 높이는 것 등이다. 인텔이 Pentium4에 적용한 기술들은 구조론적인 관점에 입각해서 원칙을 잘 지켰다고 할 수 있다. 메모리 차원에서의 속도 향상 기법은 보다 큰 메모리를 사용하고, 넓은 데이터 전송 대역폭을 가지게 하고, 그리고 전송속도를 빠르게 하는 방법이 있다. 각 방법은 물리학적인 법칙에서 빛의 속도 보다 빨라 질 수 없다. 그러므로 속도 증가에는 한계가 있다. 이것을 최소화하기 위한 방책으로는 멀티프로세서와 분산처리로 다소 얼마간의 속도 차를 해결할 수 있을 것이다.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.3 no.2
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• pp.61-71
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• 2004

Transorthogonal 코드를 블록 단위로 확장해서 얻은 코드 집합을 적절하게 부집합으로 나누고 부호화기의 코드집합으로 할당한다. 이러한 부초화기를 병렬로 구성하고 정보 비트에 의해 선택된 부호화기의 각 출력 코드들을 합산하여 전송하는 다중코드 transorthogonal 변조 방식이 제안되어 있다. 본 논문에서는 다중코드 transorthogonal 변조 시스템의 부호화기로부터의 각 출력 코드를 또 다른 정보 비트로 이진 위상 변조한 후 합산하여 전송하는 시스템을 제안한다. 다중코드 transorthogonal 변조 시스템에서 적용된 정 진폭 부호화 알고리즘과정 전폭 부호화에 사용된 잉여비트를 이용한 수신 에러 정정 알고리즘을 제안된 시스템에 수정 없이 적용할 수 있으며 다중코드 transorthogonal 변조 방식에 비해 대역폭 효율이 개선됨을 보인다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.405-408
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• 2004

본 논문에서는 FPGA와 마이크로프로세서를 이용하여 One Board화된 무선 콘트롤러 시스템의 기저대역부를 설계 하였다. 송신부에서는 컴퓨터와 연결된 마이크로프로세서부에서 컴퓨터를 통해 입력된 데이터를 병렬로 FPGA부로 전송하여 PN_code를 이용한 대역확산 거쳐 전송하고, 수신부에서는 대역역확산를 사용하여 데이터를 다시 수신측 마이크로프로세서를 통해 확인하였다. FPGA 설계는 Xilinx사의 FPGA 디자인 툴인 Xilinx Foundation3.1을 사용하였으며, FPGA configuration을 위한 타이밍 시뮬레이션을 수행하였고. Xilinx사의 SPARTAN2 2S100PQ208칩에 downloading 한 후 Agilent사의 1681A logic analyzer를 사용하여 설계된 회로의 동작을 확인 하였다. 또한 데이터의 입출력을 CPU부를 통해 컴퓨터에서 모니터링 할 수 있도록 설계하였다.

• Journal of Broadcast Engineering
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• v.17 no.3
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• pp.503-518
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• 2012

In this paper, we propose a complexity-based parallelization method of the sample adaptive offset (SAO) algorithm which is one of HEVC in-loop filters. The SAO algorithm can be regarded as region-based process and the regions are obtained and represented with a quad-tree scheme. A offset to minimize a reconstruction error is sent for each partitioned region. The SAO of the HEVC can be parallelized in data-level. However, because the sizes and complexities of the SAO regions are not regular, workload imbalance occurs with multi-core platform. In this paper, we propose a LCU-based SAO algorithm and a complexity prediction algorithm for each LCU. With the proposed complexity-based LCU processing, we found that the proposed algorithm is faster than the sequential implementation by a factor of 2.38 times. In addition, the proposed algorithm is faster than regular parallel implementation SAO by 21%.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.117-124
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• 2004

In this paper, we have been implemented the QPSK-based underwater transmission systems using DSP in order to transmit the underwater image data. We have adopted a BDPA (Block Data Parallel Architecture) to control multiple DSPs used in the transmitter and receiver in order to transmit the image data in real-time. We also have developed GUI software in order to drive and to debug the implemanted system in real-time. We have executed open sea tests in order to analyze the performance of the implemented system at East Sea near Kosung in Kangwon-Do. As a result of these experiments, it has been demonstrated that 10 kbps image data can be received without errors at 30m and 80m depth points, while the distance between the transmitter and the receiver is up to 20m.

• Journal of KIISE:Information Networking
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• v.28 no.4
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• pp.611-620
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• 2001

To meet the requirements of reliable service for various applications, a Reliable Multicast Transport Protocol should be implemented over IP Multicast where currently best-effort service is provided. Among the current researches, hierarchical tree-based mechanism has been proposed and actively studied. This mechanism is known to provide high scalability as well as reliability, but needs an additional tree configuring mechanism for building an efficient logical tree in transport layer. Bottom-up approach has been used for creating such a tree. This method has benefits from parallel tree construction for receivers, while it has some drawbacks such that it does not guarantee a loop-free tree and brings heavy message overhead during tree creation process. Therefore, this paper proposes a top-down based mechanism for constructing a control tree, which can guarantee loop-freeness by step-wise mannered tree building. From experimental simulations, it shows that the proposed mechanism has less message overhead. It is recommended that the bottom-up and the proposed top-down will be selectively used in real networks, according to the requirements of the concerned multicast applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1056-1064
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• 2010

This paper presents the approximate analysis method for the symmetric transmission line crossing the aperture in an backplane. The method of moments is used to determine the aperture impedance for the construction of the equivalent transmission line that the aperture impedance apply to the transmission line as the shunt impedance. As the results, the insertion loss increases at the specific frequency range for the impedance matching. In the case of the mismatching, we are confirmed to the insertion gain at the specific frequency. Also the horizontal length of the aperture affects to the transmission line better than vertical length. The measurement of the insertion loss is performed to verify the theoretical analysis.

• Journal of Internet Computing and Services
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• v.10 no.4
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• pp.199-211
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• 2009

Recent advancements in wireless networks have enabled support for mobile applications to transfer data over heterogeneous wireless paths in parallel using data striping technique [2]. Traditionally, high performance data transfer requires tuning of multiple TCP sockets, at sender's end, based on bandwidth delay product (BDP). Moreover, traditional techniques like Automatic TCP Buffer Tuning (ATBT), which balance memory and fulfill network demand, is designed for wired infrastructure assuming single flow on a single socket. Hence, in this paper we propose a buffer tuning technique at senders end designed to ensure high performance data transfer by striping data at transport layer across heterogeneous wireless paths. Our mechanism has the capability to become a resource management system for transport layer connections running on multi-homed mobile host supporting features for wireless link i.e. mobility, bandwidth fluctuations, link level losses. We show that our proposed mechanism performs better than ATBT, in efficiently utilizing memory and achieving aggregate throughput.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1685-1695
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• 2010

In this paper, we propose a new reliable multicast MAC protocol over the IEEE 802.11-based tactical ad hoc networks. The major contribution compared to the previous reliable multicast schemes using consecutive CTSs/ACKs is that the proposed scheme can send multiple CTS/ACK messages concurrently assisted by MC-DS/CDMA mechanisms. When multiple receivers receive the RTS/DATA message from a sender, they respond with the CTS/ACK message spread with pre-assigned code in the same time interval. The proposed scheme can reduce the overhead of multiple CTSs/ACKs. It is also possible to alleviate the received signal strength at the enemy detector and thus it improves low probability of detection performance. Through simulations and analysis, the proposed scheme outperforms that of the multiple CTSs/ACks in terms of the throughput, transmission delay and low probability of detection.