• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.553-556
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• 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)
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• v.17 no.4
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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.

• Journal of Korea Multimedia Society
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• v.22 no.2
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• pp.299-310
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• 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
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• v.38 no.12
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• pp.1086-1095
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• 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
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• v.1 no.2
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• pp.74-80
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• 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.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.3-14
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• 2013

We demonstrate a fashion of quantum channel combining and splitting, called polar quantum channel coding, to generate a quantum bit (qubit) sequence that achieves the symmetric capacity for any given binary input discrete quantum channels. The present capacity is achievable subject to input of arbitrary qubits with equal probability. The polarizing quantum channels can be well-conditioned for quantum error-correction coding, which transmits partially quantum data through some channels at rate one with the symmetric capacity near one but at rate zero through others.

• Bulletin of the Korean Space Science Society
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• 1994.04a
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• pp.18-18
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• 1994

No Abstract. See Full-text

• Journal of IKEEE
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• v.24 no.2
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• pp.550-558
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• 2020

Successive cancellation (SC) decoding that is one of the decoding algorithms for polar codes has long decoding latency and low throughput because of the nature of successive decoding. To reduce the latency and increase the throughput, various decoding structures for polar codes are presented. In this paper, we compare the previous decoding structures and analyze them by dividing into two types, pruning and multi-path decoders. Decoders for applying pruning are representative of SSC (simplified SC), Fast-SSC and redundant-LLR structures, and decoders with multi-path are representative of 2-bit SC and redundant-LLR structures. All the previous structures are compared in terms decoding latency and hardware area, and according to the comparison, the syndrome check based decoder has the lowest latency and redundant-LLR decoder has the highest hardware efficiency.

• Journal of IKEEE
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• v.22 no.4
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• pp.1168-1174
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• 2018

For the initial state of NAND flash memories, error-free and single-error cases are dominant due to a good channel environment on memory cells. It is important to deal with such cases, which affects the overall system performance. However, the conventional schemes for polar codes equally decode the codes even for the error-free and single-error cases since they cannot classify and decode separately. In this paper, a new pre-processing scheme for polar codes is proposed so as to improve the overall decoding latency by decoding the frequent error-free and single-error cases. Before the ordinary decoding process, the proposed scheme first decodes the frequent error-free and single-error cases. According to the experimental results, the proposed pre-processing scheme decreases the average decoding latency by 64% compared to the conventional scheme for (1024, 512) polar codes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.200-202
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• 2019

북극해의 해빙 감소와 러시아 야말반도의 LNG 자원 개발 등으로 북극항로를 이용한 선박의 화물운송이 점차 증가하고 있다. 극지 해역 운항선박의 안전운항과 해양환경보호를 위하여 IMO Polar Code가 2017년 1월부터 강제 발효되었으며, SOLAS협약과 MARPOL73/78 협약에 추가되어 시행되고 있다. 이에 대응하기 위하여 해양수산부 해양안전 및 해양교통시설기술개발 사업으로 2014년 11월부터 2018년 12월까지 KRISO 주관으로 '북극항로를 운항하는 선박의 항해안전 지원시스템 개발' 과제를 수행하여 KRISO Arctic safe Routing System(KARS)을 개발하였다. 한편, Polar Code에서는 빙해구역을 운항하는 선박의 구조적인 안전성을 확보하기 위한 평가 기준으로 Polar Operational Limit Assessment Indexing System (POLARIS)을 제안하고 있다. 본 논문에서는 연구배경, KARS 및 POLARIS에 대해서 간략히 설명을 하고, 두 가지 방법으로 북극해 최적항로를 각각 시뮬레이션하여 그 차이를 비교 검토하여 보인다. 결과적으로 KARS는 POLARIS를 기본적으로 고려함으로서 선박의 구조적인 안전성을 확보함과 동시에 연료소모량을 최소화 하는 경로를 탐색하므로 보다 최적화된 경로를 줄 수 있다. 향후 지속적인 수정보완 작업을 통해서 완성도를 높여갈 예정이며, 검증단계를 거쳐서 최적하고 안전한 항로와 운항 관련 정보를 선사와 해기사에게 제공하고, 북극항로 중 단기 운항계획 수립과 항해사의 안전 운항을 지원할 수 있을 것으로 기대된다.