• JSTS:Journal of Semiconductor Technology and Science
• /
• 제15권3호
• /
• pp.427-435
• /
• 2015

This paper presents a high-throughput low-complexity decoder architecture and design technique to implement successive-cancellation (SC) polar decoding. A novel merged processing element with a one's complement scheme, a main frame with optimal internal word length, and optimized feedback part architecture are proposed. Generally, a polar decoder uses a two's complement scheme in merged processing elements, in which a conversion between two's complement and sign-magnitude requires an adder. However, the novel merged processing elements do not require an adder. Moreover, in order to reduce hardware complexity, optimized main frame and feedback part approaches are also presented. A (1024, 512) SC polar decoder was designed and implemented using 40-nm CMOS standard cell technology. Synthesis results show that the proposed SC polar decoder can lead to a 13% reduction in hardware complexity and a higher clock speed compared to conventional decoders.

• 한국통신학회논문지
• /
• 제38C권1호
• /
• pp.109-117
• /
• 2013

극 부호(polar codes)는 광범위한 이진 입력 이산 무기억 채널(binary input discrete memoryless channel: BI-DMC)에서 채널 용량에 달성하는 것이 이론적으로 증명된 최초의 채널부호이다. 하지만 유한한 길이를 갖는 극 부호는 연속 제거 리스트(successive-cancellation list: SCL) 복호기에서 오류마루(error floor)가 발생하는 문제점이 있다. 선행 연구에 따르면 이 오류마루 현상은 극 부호에 오류 검출 코드(error detection codes) 중 하나인 CRC(Cyclic Redundancy Check) 부호를 연접했을 때 효과적으로 낮출 수 있는 것으로 알려져 있다. 본 논문에서는 외부 부호(outer codes)를 사용하지 않고 극 부호와 RM(Reed-Muller) 부호의 생성 행렬 연관성을 이용하여 기존 극 부호보다 확장된 최소거리를 갖는 극 부호를 제안한다. 그리고 제안된 극 부호와 CRC 부호를 연접한 극 부호의 성능을 비교한다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년 영문 학술대회
• /
• pp.553-556
• /
• 2008

A Magneto Plasma Sail(MPS) produces propulsive force by the interaction between the solar wind and an artificial magnetic field inflated by injecting plasma. Using a 2D hybrid PIC code, we evaluate the inflation of magnetic field when Argon(Ar) plasma with different ${\beta}_{in}$ including the value less than one is injected into the dipolar magnetic field generated by a superconducting coil. It is found that the magnetic field can be inflated by injecting plasma within an angle of $30^{\circ}$ in the polar direction and the magnetic field decays in the polar direction according to $B{\propto}r^{-2.4}$ after the plasma(${\beta}_{in}$=0.1) is injected.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제17권4호
• /
• pp.1296-1309
• /
• 2023

In this paper, based on the soft cancellation (SCAN) bit-flipping (SCAN-BF) algorithm, a generalized SCAN bit-flipping (GSCAN-BF-Ω) decoding algorithm is carried out, where Ω represents the number of bits flipped or corrected at the same time. GSCAN-BF-Ω algorithm corrects the prior information of the code bits and flips the prior information of the unreliable information bits simultaneously to improve the block error rate (BLER) performance. Then, a joint threshold scheme for the GSCAN-BF-2 decoding algorithm is proposed to reduce the average decoding complexity by considering both the bit channel quality and the reliability of the coded bits. Simulation results show that the GSCAN-BF-Ω decoding algorithm reduces the average decoding latency while getting performance gains compared to the common multiple SCAN bit-flipping decoding algorithm. And the GSCAN-BF-2 decoding algorithm with the joint threshold reduces the average decoding latency further by approximately 50% with only a slight performance loss compared to the GSCAN-BF-2 decoding algorithm.

• 한국멀티미디어학회논문지
• /
• 제22권2호
• /
• pp.299-310
• /
• 2019

Most web documents are written in Cartesian coordinates, so the study of vertical arrangement of text has been well organized, while the study of circular arrangement is very early. With the recent development of circular display devices, the demand for circular arrangement of texts is increasing. Thus, we proposed a CSS3 extended specification of polar coordinate layout for the circular placement of text. First, we defined the concept of fan model for the text arrangement in polar coordinate which is corresponding to box model in Cartesian coordinate. And, we described new definition on the directions of sentence, paragraph and text orientation in polar coordinate. Based on this new definitions, we developed the extended specification consisting of three parts. A part for setting the fan model, a part for setting directions, and a part for setting typesetting properties. To verify the feasibility of the proposed specification in current web browsers, a preprocessor was developed and sample contents were examined. We compared the code length of the sample contents implemented using other JavaScript library CssWarp.js so as to verify the efficiency of the proposed specification.

• Molecules and Cells
• /
• 제38권12호
• /
• pp.1086-1095
• /
• 2015

The psychrophilic organism Colwellia psychrerythraea strain 34H produces extracellular polysaccharide substances to tolerate cold environments. Sedoheptulose 7-phosphate isomerase (GmhA) is essential for producing $\small{D}$-glycero-$\small{D}$-mannoheptose 7-phosphate, a key mediator in the lipopolysaccharide biosynthetic pathway. We determined the crystal structure of GmhA from C. psychrerythraea strain 34H (CpsGmhA, UniProtKB code: Q47VU0) at a resolution of $2.8{\AA}$. The tetrameric structure is similar to that of homologous GmhA structures. Interestingly, one of the catalytic residues, glutamate, which has been reported to be critical for the activity of other homologous GmhA enzymes, is replaced by a glutamine residue in the CpsGmhA protein. We also found differences in the conformations of several other catalytic residues. Extensive structural and sequence analyses reveal that CpsGmhA shows high similarity to Escherichia coli DnaA initiatorassociating protein A (DiaA). Therefore, the CpsGmhA structure reported here may provide insight into the structural and functional correlations between GmhA and DiaA among specific microorganisms.

• Journal of Semiconductor Engineering
• /
• 제1권2호
• /
• pp.74-80
• /
• 2020

Due to its superior error correcting performance with affordable hardware complexity, the Polar code becomes one of the most important error correction codes (ECCs) and now intensively examined to check its applicability in various fields. However, Successive Cancellation (SC) decoding that brings the advanced Successive Cancellation List (SCL) decoding suffers from the long latency due to the nature of serial processing limiting the practical implementation. To mitigate this problem, many decoding architectures, mainly divided into pruning and parallel decoding, are presented in previous manuscripts. In this paper, we compare the recent SC decoding architectures and analyze them using a tree structure.

• 전자공학회논문지
• /
• 제50권8호
• /
• pp.3-14
• /
• 2013

본 논문에서는 어떠한 이진 입력 이산 퀀텀채널(quantum channel)이 주어지더라도 대칭 용량을 달성할 수 있는 qubit(quantum bit)를 생성하기 위해, 극(polar) 퀀텀 채널 코딩이라 부르는 퀀텀 채널의 결합과 분리 형태를 제시한다. 현재의 용량은 동등 확률을 갖는 임의의 qubit 입력에 따라서 결정된다. 퀀텀채널의 분극은 대칭채널이 1에 근접하면 rate 1로 아니면 rate 0으로 전송하는 채널을 통해 퀀텀 데이터를 부분적으로 전송하는 퀀텀 오류정정 부호화에 아주 적합하다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
• /
• 한국우주과학회 1994년도 한국우주과학회보 제3권1호
• /
• pp.18-18
• /
• 1994

No Abstract. See Full-text

• 전기전자학회논문지
• /
• 제24권2호
• /
• pp.550-558
• /
• 2020

Polar code의 복호 기법 중에 하나인 연속 제거 (successive cancellation; SC) 복호는 순차적으로 복호를 수행해야하는 특성으로 인해 지연시간이 길고, 복호를 위해 필요한 하드웨어 면적이 크다. 이를 극복하기 위하여 다수의 연구들이 진행되었으며, 본 논문에서는 연속 제거 복호를 기반으로 한 복호 기법을 가지치기 (pruning) 복호 기법들과 다중-경로 (multi-path) 복호기법들로 나누어 정리하였다. 가지치기 복호기법에는 SSC (simplified SC), fast-SSC, 신드롬 판단 기반 복호 등이 있으며, 다중-경로 복호 기법에는 2-비트 연속 제거 복호와 redundant-LLR 표현 기반의 복호가 있다. 본 논문에서는 SSC, fast-SSC, 신드롬 판단, 2-비트 연속 제거, 그리고 redundant-LLR 표현 기반의 복호 기법들을 지연시간과 하드웨어 면적 측면에서 비교했으며, 비교 결과 신드롬 판단 기반 복호기법이 지연시간이 가장 짧고, redundant-LLR 표현 기반의 복호가 하드웨어 면적이 가장 작은 복호 기법이다.