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Improving Performance of LDPC-Coded Links via Partial Superposition Retransmission

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Journal of Communications and Information Networks 2022年第3期7卷 259-268页

作者： Yinchu wang qianfan wang Ming Jiang Xiao Ma School of Computer Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China Guangdong Key Laboratory of Information Security Technology Sun Yat-sen UniversityGuangzhou 510006China School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 510006China

In this paper,we propose a transmission scheme for uplink and downlink transmissions,where the fifth generation(5G)low-density parity-check(LDPC)codes are implemented for error correction.In the proposed scheme,the acknowledgment(ACK)or negative acknowledgment(NACK)feedback information is transmitted along with the payload data by cyclically shifting coded sequence,while the re-transmitted codewords are superimposed(XORed)partially on the current codewords.The distinguished feature of the proposed transmission scheme is that it requires neither extra transmission bandwidth nor extra transmission power.We also propose to truncate the error patterns for the purpose of reducing the implementation complexity and reducing the error propagation.Numerical results show that the proposed scheme significantly outperforms conventional LDPC-coded transmission.For the 5G LDPC code with length 1920 at the signal-to-noise ratio(SNR)of 1.3 dB,the word error rate(WER)of the data transmitted by the proposed scheme is about 10^(−4),while that of the conventional LDPC-coded transmission is about 10^(−2).

关键词： block Markov superposition transmission(BMST) 5G LDPC codes free-ride coding hybrid automatic repeat request(HARQ) partial superposition

Block Markov superposition transmission of LDPC codes

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Journal of Information and Intelligence

Journal of Information and Intelligence 2023年第2期1卷 115-133页

作者： qianfan wang Kongjing Guo Xiao Ma School of Computer Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China Guangdong Key Laboratory of Information Security Technology Sun Yat-sen UniversityGuangzhou 510006China

In this paper,based on the block Markov superposition transmission(BMST)technique,we present a new class of coupled low-density parity-check(LDPC)codes for the transport block(TB)-based transmission to improve the error-correcting performance.For encoding,the previous LDPC codewords corresponding to a TB(at prior time slot)are interleaved and superimposed onto the current LDPC codewords,resulting in the transmitted codewords.For decoding,the sliding window decoding algorithm with sum-product or min-sum implementations can be employed,inheriting a relatively low-latency decoding.A distinguished advantage of the proposed coded transmission over spatially coupled LDPC(SC-LDPC)codes is that the encoder/decoder of the proposed codes can be designed by reusing the encoder/decoder architecture of component block LDPC codes.To analyze the waterfall performance of BMST-LDPC code ensembles,we present the protograph-based EXIT chart analysis,which can efficiently predict the error-correcting performance in waterfall region.To analyze the error-floor performance of BMST-LDPC codes,we employ the genie-aided(GA)lower bound,which can efficiently predict the error-correcting performance in error-floor region.For ease of implementation,the BMST-LDPC codes are constructed by taking the(2,4)-raptor-like LDPC codes or the 5G LDPC codes as the basic components.The numerical results reveal that the proposed codes can have capacity-approaching performance,exhibiting a gap of 0.007 dB away from the corresponding Shannon limit.They also reveal that,by using the proposed BMST construction,the error-correcting performance of the original 5G block LDPC codes can be significantly improved,achieving coding gains up to one dB over the AWGN channels and two dB over the fast fading channels.

关键词： 5G NR Block Markov superposition transmission (BMST) Low-density parity-check(LDPC)codes Spatially-coupled LDPC(SC-LDPC)codes

Semi-LDPC Convolutional Codes:Construction and Low-Latency Windowed List Decoding

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Journal of Communications and Information Networks 2021年第4期6卷 411-419页

作者： qianfan wang Suihua Cai Li Chen Xiao Ma School of Electronics and Communication Engineering Sun Yat-sen UniversityGuangzhou 510006China School of Computer Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China Guangdong Key Laboratory of Information Security Technology Sun Yat-sen UniversityGuangzhou 510006China School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 510006China

This paper presents a new coding scheme called semi-low-density parity-check convolutional code(semi-LDPC-CC),whose parity-check matrix consists of both sparse and dense sub-matrices,a feature distinguished from the conventional LDPC-CCs.We propose sliding-window list(SWL)decoding algorithms with a fixed window size of two,resulting in a low decoding latency but a competitive error-correcting performance.The performance can be predicted by upper bounds derived from the first event error probability and by genie-aided(GA)lower bounds estimated from the underlying LDPC block codes(LDPC-BCs),while the complexity can be reduced by truncating the list with a threshold on the difference between the soft metrics in the serial decoding implementation.Numerical results are presented to validate our analysis and demonstrate the performance advantage of the semi-LDPC-CCs over the conventional LDPC-CCs.

关键词： low-density parity-check convolutional codes(LDPC-CCs) spatially coupled LDPC(SC-LDPC)codes sliding-window list(SWL)decoding

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《德意志悲苦剧的起源》与本雅明的哲学规划

清华大学学报（哲学社会科学版） 2024年第1期39卷 158-169,240,241页

作者：赵千帆同济大学人文学院哲学系上海200092

《德意志悲苦剧的起源》呈现了本雅明思想发展中期一个极具独创性的哲学规划,重构这一规划的基本轮廓有助于从哲学层面对这部作品的整体理解。它以“认识批判”为纲领,尝试通过对艺术作品的分析进行跨学科的理论试验,对一个历史时代获... 详细信息

《德意志悲苦剧的起源》呈现了本雅明思想发展中期一个极具独创性的哲学规划,重构这一规划的基本轮廓有助于从哲学层面对这部作品的整体理解。它以“认识批判”为纲领,尝试通过对艺术作品的分析进行跨学科的理论试验,对一个历史时代获得全面和具有启示性的认识。这一规划确立了自己的操作方式,包括对研究材料的拆解重组、对历史起源的辩证视角和通过对前人概念的重新部署来勾勒真理的形态。这一操作过程同时也是哲学批评的书写实践,在描绘出悲苦剧的艺术形式的同时,也检验着哲学思考与书写的边界。这个哲学规划汇集了思想史众多线索,也在与传统哲学话语的交错中开辟了一条具有独特历史意识的哲学考察路线。

关键词：本雅明《德意志悲苦剧的起源》艺术作品寄喻

碳基非金属催化剂在有机合成领域的应用及机理研究

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有机化学 2024年第1期44卷 137-147页

作者：赵茜帆陈永正张世明遵义医科大学药学院贵州省绿色制药工程研究中心贵州省仿制药工程研究中心贵州省生物催化与手性药物合成重点实验室贵州遵义563000 遵义医科大学基础药理教育部重点实验室特色民族药教育部国际合作联合实验室贵州遵义563000

碳基非金属催化剂是指包括碳纳米管(CNTs)、氧化石墨烯(GO)、石墨烯(G)、活性炭(AC)及其掺杂或修饰后得到的材料作为用于涉及能量转换等关键反应过程的催化剂.碳基非金属催化剂由于具有来源丰富、成本低、对环境友好、后处理简单、可持... 详细信息

碳基非金属催化剂是指包括碳纳米管(CNTs)、氧化石墨烯(GO)、石墨烯(G)、活性炭(AC)及其掺杂或修饰后得到的材料作为用于涉及能量转换等关键反应过程的催化剂.碳基非金属催化剂由于具有来源丰富、成本低、对环境友好、后处理简单、可持续发展等优点,近年来被成功应用于有机合成领域.基于碳基非金属催化剂应用于氧化反应、还原反应、取代反应和偶联反应被成功报道,但针对碳基非金属催化剂应用于有机合成领域进行催化的活性位点的研究目前仍处于早期发展阶段.近年来,科学家们针对其机理的研究主要集中于对催化剂的表征分析和第一性原理计算,但未得出相对一致的实验结论.对碳基非金属催化剂在有机合成领域的应用及机理研究进行了综述.

关键词：碳基非金属催化剂有机合成机理研究

礼让视域下GDPR域外管辖的冲突及中国的因应

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网络安全与数据治理 2024年第5期43卷 76-82页

作者：程千帆海南大学法学院海南海口570228

在数字经济时代,数据已经成为了一种全新的资产类型,国家对数据的掌控能力成为其综合国力的外在体现,而当代国家对数据重视与保护加剧了数据管辖权冲突。在此情形下,欧盟《通用数据保护条例》(GDPR)通过“实体标准”“目的指向标准”“... 详细信息

在数字经济时代,数据已经成为了一种全新的资产类型,国家对数据的掌控能力成为其综合国力的外在体现,而当代国家对数据重视与保护加剧了数据管辖权冲突。在此情形下,欧盟《通用数据保护条例》(GDPR)通过“实体标准”“目的指向标准”“使领馆标准”三重管辖扩张实现对全球数据的“长臂管辖”,但其关于适用地域范围的规定与其他国家的属地管辖冲突,体现出欧盟在数据保护方面呈现出单边扩张的趋势,易诱发数据管辖权冲突。故此,基于优利克·胡伯提出解决管辖冲突的“国际礼让原则”,分析GDPR三个适用地域界定标准下存在的管辖权冲突,考察国际礼让原则在数据管辖权冲突中可用性与适用基础,并对不同礼让形式在数据管辖权冲突中的适用予以分析,并基于GDPR域外适用管辖权冲突提出补充数据管辖模式、对接国际跨域数据治理、坚持礼让互惠协作的中国因应,以期为我国畅通域外数据保护提供新思路。

关键词： GDPR 国际礼让域外适用管辖权冲突

Occurrence, distribution and risk assessment of antibiotics at various aquaculture stages in typical aquaculture areas surrounding the Yellow Sea

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Journal of Environmental Sciences 2023年第4期126卷 621-632页

作者： Jiachao Zhang Xuanrui Zhang Yang Zhou qianfan Han Xiaoli wang Chao Song Shuguang wang Shan Zhao Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong UniversityQingdao 266237China Water Science and Environmental Engineering Research Center College of Chemical and Environmental EngineeringShenzhen UniversityShenzhen 518060China Qingdao Municipal Bureau of Ecology and Environment Qingdao 266003China Analysis and Test Center Qilu University of Technology(Shandong Academy of Sciences)Jinan 250014China

The pollution of antibiotics commonly existed throughout the entire aquaculture process,but the residues of antibiotics at different aquaculture stages have rarely been studied.This study investigated the occurrence,distribution and risk assessment of antibiotics at different aquaculture stages (the non-aquaculture stage,the early aquaculture stage,the middle aquaculture stage,and the late aquaculture stage) in two typical marine aquaculture areas(Mahegang River and Dingzi Bay) surrounding the Yellow Sea.Fluoroquinolones and tetracyclines were commonly used antibiotics in the aquaculture of these areas with high detection frequencies (17%to 83%).Compared among four aquaculture stages,the highest concentration of antibiotics (9032.08 ng/L) in aquaculture ponds was detected at the late aquaculture stage.And the antibiotic pollution level of natural water was directly related to the aquaculture stages.Similarly,at the aquaculture stages,the detection frequency of antibiotics in sediments was higher than that at the non-aquaculture stage.Based on the correlation analysis,the concentration of main antibiotics in water showed a positive correlation with total nitrogen (p<0.05) and chlorophyll a (p<0.01),while it showed a negative correlation with salinity (p<0.01) in coastal water of the Dingzi Bay.According to the risk assessment,with the development of aquaculture stages,the selection pressure of fluoroquinolones and tetracyclines on resistant bacteria had increased.And the ecological risks caused by sulfonamides and tetracyclines to aquatic organisms had also increased markedly.Overall,this study may provide a reference for formulating regulatory policies regarding antibiotic use at different aquaculture stages.

关键词： Antibiotics Aquaculture stages Correlation analysis Risk assessment

电动汽车用多相电驱重构型车载充电系统关键技术综述

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中国电机工程学报 2024年第13期44卷 5281-5297页

作者：於锋殷琪皓佟明昊张千帆南通大学电气工程学院南京理工大学机械工程学院哈尔滨工业大学电气工程及自动化学院

电驱重构型车载充电系统为电动汽车电气部分提供了一种全新轻量化设计思路，旨在利用电驱单元分时执行电驱与充电2种变流功能。相较于三相电驱系统，多相电驱系统具有输出转矩平滑、容错性能强等诸多优势特性。鉴于此，该文首先归纳现... 详细信息

电驱重构型车载充电系统为电动汽车电气部分提供了一种全新轻量化设计思路，旨在利用电驱单元分时执行电驱与充电2种变流功能。相较于三相电驱系统，多相电驱系统具有输出转矩平滑、容错性能强等诸多优势特性。鉴于此，该文首先归纳现有并网式多相电驱重构型车载充电系统的拓扑结构与控制策略，并介绍其容错运行方案；然后，着重分析太阳能电动汽车用多能量端口电驱重构型车载充电系统的工作原理与控制策略；最后，总结全文并对多相电驱重构型车载充电系统的发展方向进行展望。

关键词：电驱重构型车载充电系统电动汽车多相电机太阳能电动汽车关键技术

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多级中空纳米纤维二次电池电极材料

科学通报 2024年第16期69卷 2157-2173页

作者：高松伟郭威牟粤朱柯平崔志民满兴坤张千帆王女赵勇北京航空航天大学化学学院仿生智能界面科学与技术教育部重点实验室仿生能源材料与器件北京市重点实验室北京100191 北京航空航天大学物理学院北京100191 北京航空航天大学材料科学与工程学院北京100191

多级中空纳米纤维材料具有结构可控、成分可调的优点,在二次电池电极材料领域应用广泛.在结构方面:多级中空结构可以有效缓冲电极材料在电化学反应离子嵌/脱过程中的体积变化,阻止电极材料粉碎、脱落,增加电解液和电极材料的有效接触面... 详细信息

多级中空纳米纤维材料具有结构可控、成分可调的优点,在二次电池电极材料领域应用广泛.在结构方面:多级中空结构可以有效缓冲电极材料在电化学反应离子嵌/脱过程中的体积变化,阻止电极材料粉碎、脱落,增加电解液和电极材料的有效接触面积,缩短离子/电子传输路径;在成分方面:可以实现不同特性材料的合理耦合,提升电极材料电导率,加速氧化还原反应动力学.多级中空纳米纤维结构和成分的协同增强作用在提升二次电池容量、倍率、循环性能方面效果显著.本文归纳了现阶段制备多级中空结构纳米纤维的几类方法,包括单针头静电纺丝、多流体静电纺丝和其他合成方法(模板法、水热法、自组装法等).随后,总结了不同结构、成分的纤维在二次电池(如锂、钠、钾离子电池,锂/钠-硫电池,锂金属-空气电池,超级电容器等)中的应用进展.最后,探讨了多级中空结构纳米纤维材料在电化学储能领域的应用潜力.

关键词：多级中空结构纳米纤维异质结构二次电池电极材料