• 한국통신학회논문지
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• 제39A권10호
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• pp.585-592
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• 2014

It is well known that serial belief propagation (BP) decoding for low-density parity-check (LDPC) codes achieves faster convergence without any increase of decoding complexity per iteration and bit error rate (BER) performance loss than standard parallel BP (PBP) decoding. Serial BP (SBP) decoding, such as horizontal SBP (H-SBP) decoding or vertical SBP (V-SBP) decoding, updates check nodes or variable nodes faster than standard PBP decoding within a single iteration. In this paper, we propose combined horizontal-vertical SBP (CHV-SBP) decoding. By the same reasoning, CHV-SBP decoding updates check nodes or variable nodes faster than SBP decoding within a serialized step in an iteration. CHV-SBP decoding achieves faster convergence than H-SBP or V-SBP decoding. We compare these decoding schemes in details. We also show in simulations that the convergence rate, in iterations, for CHV-SBP decoding is about $\frac{1}{6}$ of that for standard PBP decoding, while the convergence rate for SBP decoding is about $\frac{1}{2}$ of that for standard PBP decoding. In simulations, we use recently proposed generalized LDPC (GLDPC) codes with binary cyclic codes (BCC).

• 영어어문교육
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• 제11권2호
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• pp.35-50
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• 2005

Thirty six EFL freshman students at the College of Languages and Translation, King Saud University, Riyadh, Saudi Arabia were given a dictation, a listening comprehension test and a decoding test. The purpose of the study was to find out whether EFL freshmen students' spelling ability correlates with their listening comprehension and decoding skills. Data analysis showed that the typical EFL freshman student misspelled 41.5% of the words on the dictation, gave 49.5% correct responses on the listening comprehension test, and 52% correct responses on the decoding test. The median and mean scores showed that the subjects' spelling, listening and decoding achievement is low, which implied that the subjects were having spelling, listening comprehension and decoding difficulties. The students' spelling errors and correct listening comprehension and decoding responses revealed strong correlations between spelling ability, listening comprehension and decoding skills. This means that good spelling ability in EFL is related to good listening comprehension and good decoding skills. The better the listening comprehension and decoding abilities, the fewer the spelling errors. When listening comprehension and decoding skills are poor, spelling ability is also poor. Recommendations for spelling, listening and decoding instruction are given.

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

• ETRI Journal
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• 제28권3호
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• pp.301-310
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• 2006

In mobile communications, a class of variable-complexity algorithms for convolutional decoding known as sequential decoding algorithms is of interest since they have a computational time that could vary with changing channel conditions. The Fano algorithm is one well-known version of a sequential decoding algorithm. Since the decoding time of a Fano decoder follows the Pareto distribution, which is a heavy-tailed distribution parameterized by the channel signal-to-noise ratio (SNR), buffers are required to absorb the variable decoding delays of Fano decoders. Furthermore, since the decoding time drawn by a certain Pareto distribution can become unbounded, a maximum limit is often employed by a practical decoder to limit the worst-case decoding time. In this paper, we investigate the relations between buffer occupancy, decoding time, and channel conditions in a system where the Fano decoder is not allowed to run with unbounded decoding time. A timeout limit is thus imposed so that the decoding will be terminated if the decoding time reaches the limit. We use discrete-time semi-Markov models to describe such a Fano decoding system with timeout limits. Our queuing analysis provides expressions characterizing the average buffer occupancy as a function of channel conditions and timeout limits. Both numerical and simulation results are provided to validate the analytical results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(3)
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• pp.133-136
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• 2000

A RVLC(Reversible Variable Length Code) with an efficient table memory is proposed in this paper. In the conventional decoding methods, the weight of symbols and code values are used for the decoding table. These methods can be applied for Huffman decoding. In VLC decoding, many studies have been done for memory efficiency and decoding speed. We propose an improved table construction method for general VLC and RVLC decoding, which uses the transition number of bits within a symbol with an enhanced weight decomposition. In this method, tile table for RVLC decoding can be implemented with a smaller memory

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.14-15
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• 2008

In this paper, a new iterative decoding of LDPC codes is proposed. The decoding is based on the posteriori probability of each belief propagation (BP) decoding and an additional postprocessing, that is, erasure decoding of LDPC codes. It turned out that the new method consistently improves the decoding performance on various classes of LDPC codes. For example it removes the error floor of Margulis codes effectively.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1984년도 춘계학술발표회논문집
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• pp.22-24
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• 1984

In this paper, the (15,7) cylic codesused EG(2,2) were decoded by one step majority logic decoding. This decoding algorithm is based on the properties of finite geometries and can be simply implemented for moderate length n. especially one step majority logic decoding is attractive because the complexity and the cost of the majority logic decoder increase very rapidly with L, the number of decoding steps. The theorectical and experimental results show that the majority logic decoding presented in this paper is a relatively effective decoding scheme.

• 대한의용생체공학회:의공학회지
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• 제38권6호
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• pp.342-351
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• 2017

뉴럴 디코딩은 뉴론이 발화한 스파이크 트레인으로부터 뉴론에 인가된 원 자극을 추정하는 작업을 말한다. 디코딩은 뉴론들끼리 어떻게 신호를 주고 받는 지를 이해함으로써 궁극적으로 뇌가 어떻게 정보처리를 하는 지 이해하는 기초적인 작업이다. 이 논문에서 우리는 3가지 뉴럴 디코딩 방법, 즉 빈도 디코딩, 시간 디코딩, 군집 디코딩 방법에 대해 설명하겠다. 빈도 디코딩은 자극에 대한 스파이크의 발화빈도 정보를 이용하여 자극을 복원하는 방법을 말한다. 역사적으로 가장 먼저 시도되었고 가장 간단한 디코딩 방법이다. 그러나 정수 개인 스파이크 개수로부터 빈도를 계산하는 과정에서 빈도자체가 불연속이고 양자화될 가능성이 높기 때문에 간단하고 정적인 자극이 아닌 경우 빈도 디코딩으로는 자극을 복원하기 어렵다는 한계를 가지고 있다. 시간 디코딩은 스파이크 발생 빈도가 아닌 개별 스파이크들의 발생시각을 이용한 디코딩 방법을 말하며 실제 빠르게 변화하는 자극의 경우 신경세포는 빈도 디코딩이 아니라 시간 디코딩을 통해 자극을 추정하는 것으로 이해되고 있다. 군집 디코딩은 단일 신경세포가 아닌 군집 신경세포로부터 자극을 복원하는 방법이다. 군집 디코딩은 단일 신경 세포 디코딩에 비해 신경 세포의 가변성에 따른 불확실성을 감소시킬 수 있고 서로 다른 자극의 특성을 동시에 표현할 수 있다는 장점을 갖는다. 이 논문에서는 먼저 세 가지 뉴럴디코딩 방법에 대해 소개하고 정보이론이 뉴럴디코딩에 어떻게 적용되는 지를 다룬 후 마지막으로 최근에 각광받고 있는 기계학습 방법에 의한 뉴럴 디코딩에 대해 다루도록 하겠다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권10호
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• pp.2479-2496
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• 2013

Increasing demand for Full High-Definition (FHD) video and Ultra High-Definition (UHD) video services has led to active research on high speed video processing. Widespread deployment of multi-core systems has accelerated studies on high resolution video processing based on parallelization of multimedia software. Even if parallelization of a specific decoding step may improve decoding performance partially, such partial parallelization may not result in sufficient performance improvement. Particularly, entropy decoding has often been considered separately from other decoding steps since the entropy decoding step could not be parallelized easily. In this paper, we propose a parallelization technique called Integrated Multi-Threaded Parallelization (IMTP) which takes parallelization of the entropy decoding step, with other decoding steps, into consideration in an integrated fashion. We used the Simultaneous Multi-Threading (SMT) technique with appropriate thread scheduling techniques to achieve the best performance for the entire decoding step. The speedup of the proposed IMTP method is up to 3.35 times faster with respect to the entire decoding time over a conventional decoding technique for H.264/AVC videos.

• 대한전자공학회논문지TC
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• 제46권3호
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• pp.9-14
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• 2009

최근에 간단한 ML 복호가 가능한 rate-2, $2{\times}2$ 시공간 부호가 개발되었다. 비록 이러한 간단한 ML 복호 알고리즘이 ML 복호 복잡도를 줄여 주지만 여전히 향상될 여지가 남아 있다. 본 논문에서는 간섭제거 방법을 사용하여 ML 복호와 거의 동일한 성능을 가지면서 rate-2, $2{\times}2$ 시공간 부호를 위한 효율적인 복호 알고리즘을 제안한다. 제안된 알고리즘의 복호 복잡도는 기존의 간단한 ML 복호에 비해서도 더욱 감소하며 변조 차수가 클수록 복호 복잡도 감소율은 더욱 증가한다.