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Numerical investigation on permeability evolution behavior of rock by an improved flow-coupling algorithm in particle flow code 被引量:10
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作者 ZENG Wei YANG Sheng-qi +1 位作者 TIAN Wen-ling WEN Kai 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第6期1367-1385,共19页
Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass... Permeability is a vital property of rock mass, which is highly affected by tectonic stress and human engineering activities. A comprehensive monitoring of pore pressure and flow rate distributions inside the rock mass is very important to elucidate the permeability evolution mechanisms, which is difficult to realize in laboratory, but easy to be achieved in numerical simulations. Therefore, the particle flow code (PFC), a discrete element method, is used to simulate permeability behaviors of rock materials in this study. Owe to the limitation of the existed solid-fluid coupling algorithm in PFC, an improved flow-coupling algorithm is presented to better reflect the preferential flow in rock fractures. The comparative analysis is conducted between original and improved algorithm when simulating rock permeability evolution during triaxial compression, showing that the improved algorithm can better describe the experimental phenomenon. Furthermore, the evolution of pore pressure and flow rate distribution during the flow process are analyzed by using the improved algorithm. It is concluded that during the steady flow process in the fractured specimen, the pore pressure and flow rate both prefer transmitting through the fractures rather than rock matrix. Based on the results, fractures are divided into the following three types: I) fractures link to both the inlet and outlet, II) fractures only link to the inlet, and III) fractures only link to the outlet. The type I fracture is always the preferential propagating path for both the pore pressure and flow rate. For type II fractures, the pore pressure increases and then becomes steady. However, the flow rate increases first and begins to decrease after the flow reaches the stop end of the fracture and finally vanishes. There is no obvious pore pressure or flow rate concentration within type III fractures. 展开更多
关键词 rock mechanics fluid-solid coupling particle flow code (PFC) PERMEABILITY triaxial compression
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Verification of a self-developed CFD-based multi-physics coupled code MPC-LBE for LBE-cooled reactor 被引量:12
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作者 Zhi-Xing Gu Qing-Xian Zhang +4 位作者 Yi Gu Liang-Quan Ge Guo-Qiang Zeng Mu-Hao Zhang Bao-Jie Nie 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第5期84-100,共17页
To perform an integral simulation of a pool-type reactor using CFD code,a multi-physics coupled code MPC-LBE for an LBE-cooled reactor was proposed by integrating a point kinetics model and a fuel pin heat transfer mo... To perform an integral simulation of a pool-type reactor using CFD code,a multi-physics coupled code MPC-LBE for an LBE-cooled reactor was proposed by integrating a point kinetics model and a fuel pin heat transfer model into self-developed CFD code.For code verification,a code-to-code comparison was employed to validate the CFD code.Furthermore,a typical BT transient benchmark on the LBE-cooled XADS reactor was selected for verification in terms of the integral or system performance.Based on the verification results,it was demonstrated that the MPC-LBE coupled code can perform thermal-hydraulics or safety analyses for analysis for processes involved in LBE-cooled pool-type reactors. 展开更多
关键词 LBE-cooled pool-type reactor Computational fluid dynamics Multi-physics coupling code Safety analysis code VERIFICATION
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Performance of Block Diagonalization Broadcasting Scheme for Multiuser MIMO System Operating in Presence of Spatial Correlation and Mutual Coupling 被引量:1
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作者 Feng Wang Marek E Bialkowski Xia Liu 《International Journal of Communications, Network and System Sciences》 2010年第3期266-272,共7页
In this paper, the capacity of a multiuser Multiple Input Multiple Output (MIMO) system employing the block diagonalization broadcasting scheme in presence of spatial correlation and mutual coupling is investigated. I... In this paper, the capacity of a multiuser Multiple Input Multiple Output (MIMO) system employing the block diagonalization broadcasting scheme in presence of spatial correlation and mutual coupling is investigated. It is shown by computer simulations that, in general, the presence of spatial correlation decreases the capacity of a multiuser MIMO system. However, for some particular antenna element spacing mutual coupling decreases the spatial correlation rendering an increased capacity. The optimized diagonalization broadcasting technique with a two-stage power allocation scheme is proposed and verified. The presented simulations results confirm the advantage of the proposed broadcasting scheme. 展开更多
关键词 MULTIUSER MIMO BLOCK Diagonalizaiton Mutual coupling Dirty PAPER CODING
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Dual-Polarized RIS-Based STBC Transmission with Polarization Coupling Analysis 被引量:1
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作者 ZHOU Mingyong CHEN Xiangyu +4 位作者 TANG Wankai KE Jun Chen JIN Shi CHENG Qiang CUI Tie Jun 《ZTE Communications》 2022年第1期63-75,共13页
The rapid development of the reconfigurable intelligent surface(RIS)technology has given rise to a new paradigm of wireless trans-mitters.At present,most research works on RIS-based transmitters focus on single-polari... The rapid development of the reconfigurable intelligent surface(RIS)technology has given rise to a new paradigm of wireless trans-mitters.At present,most research works on RIS-based transmitters focus on single-polarized RISs.In this paper,we propose a dual-polarized RIS-based transmitter,which realizes 4-transmit space-time block coding(STBC)transmission by properly partitioning RIS’s unit cells and utilizing the degree of freedom of polarization.The proposed scheme is evaluated through a prototype system that utilizes a fabricated dual-polarized phase-adjustable RIS.In particular,the polarization coupling phenomenon in each unit cell of the employed dual-polarized RIS is modeled and analyzed.The experimental results are in good agreement with the theoretical modeling and analysis results,and an initial re-search effort is made on characterizing the polarization coupling property in the dual-polarized RIS. 展开更多
关键词 reconfigurable intelligent surface space-time coding dual polarization coupling modeling PROTOTYPING
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Coupling of 3D Eulerian and Lagrangian Spray Approaches in Industrial Combustion Engine Simulations 被引量:2
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作者 Wilfried Edelbauer 《Journal of Energy and Power Engineering》 2014年第1期190-200,共11页
The Lagrangian DDM (discrete droplet model) is state-of-the-art for CFD (computational fluid dynamics) simulations of mixture formation and combustion in industrial engines. A commonly known drawback of the DDM ap... The Lagrangian DDM (discrete droplet model) is state-of-the-art for CFD (computational fluid dynamics) simulations of mixture formation and combustion in industrial engines. A commonly known drawback of the DDM approach is the attenuated validity in the dense spray, where the bulk liquid disintegrates into droplets. There the assumption of single droplets surrounded by a homogenous gas field is not reasonable. In this region, the Eulerian-Eulerian multi-phase approach performs better because instead of parcels the spray is represented by the volume fractions of one bulk liquid and several droplet size class phases. A further drawback of the DDM approach is that increasing the spatial resolution of the computational grid leads to a reduced statistical convergence, since the number of spray parcels per computational cell becomes smaller. It is desirable to combine the benefits of both spray approaches in coupled CFD simulations. Therefore, the dense spray region is simulated separately with the Eulerian spray approach on a highly resolved mesh covering only the region close to the nozzle orifice. The entire engine domain with combustion and emission models is simulated with the Eulerian-Lagrangian spray approach for the dilute spray region. The two simulations are coupled through exchange of boundary conditions and model source terms. An on-line coupling interface manages the data transfer between the two simulation clients, i.e., Eulerian spray and engine client. The aim of this work is to extend the coupled spray approach in terms of exchanging combustion related heat and species sources, and consequently creating the link between Eulerian spray and combustion models. The results show mixture formation and combustion in real-case engine simulations, and demonstrate the feasibility of spray model combination in engineering applications. 展开更多
关键词 CFD code coupling COMBUSTION Eulerian spray Lagrangian spray multi-fluid approach.
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Rate-compatible spatially coupled repeat-accumulate codes via successive extension
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作者 Liu Yang Wang Bin +1 位作者 Zhang Yuzhi Sun Yanjing 《High Technology Letters》 EI CAS 2019年第2期224-229,共6页
A rate-compatible spatially coupled repeat-accumulate (RC-SC-RA) code is proposed. Its protograph is obtained by extending a given (J, K, L) SC-RA coupled chain (denoted as the mother chain) with extra check nodes and... A rate-compatible spatially coupled repeat-accumulate (RC-SC-RA) code is proposed. Its protograph is obtained by extending a given (J, K, L) SC-RA coupled chain (denoted as the mother chain) with extra check nodes and parity bit nodes T times. At each time, the extension is realized via coupling the message bits in the same way as that in the mother chain. Rate-compatibility is achieved by adjusting the extension parameters and applying random puncturing technique. Density evolution analysis shows that the iterative decoding thresholds of all the member codes in the proposed RC-SC-RA code family are very close to Shannon limits over the binary erasure channel. Finite length simulation results are consistent with the thresholds well. Moreover, the proposed RC-SC-RA codes perform better than spatially coupled low density parity check (SC-LDPC) codes in decoding performance especially in lower-rate region. 展开更多
关键词 spatially coupled LDPC codes spatially coupled RA codes rate compatibility density evolution iterative decoding
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基于preCICE的多尺度耦合不确定性分析方法研究
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作者 董士豪 邓俊杰 +3 位作者 黄喆 刘紫静 李卫 赵鹏程 《核技术》 北大核心 2026年第3期136-147,共12页
当前反应堆热工水力多尺度耦合研究主要聚焦于多尺度耦合程序开发与验证,针对耦合程序不确定性的系统性研究仍较为匮乏。本研究基于preCICE开源框架,集成计算流体力学(Computational Fluid Dynamics,CFD)程序FLUENT、子通道程序SUBCHANF... 当前反应堆热工水力多尺度耦合研究主要聚焦于多尺度耦合程序开发与验证,针对耦合程序不确定性的系统性研究仍较为匮乏。本研究基于preCICE开源框架,集成计算流体力学(Computational Fluid Dynamics,CFD)程序FLUENT、子通道程序SUBCHANFLOW以及DAKOTA不确定性量化模块,构建多尺度耦合不确定性分析程序。通过建立3×3棒束模型,开展稳态与瞬态条件下的数值验证,并进行不确定性量化与灵敏度分析。研究结果显示:1)稳态工况下耦合系统轴向温度分布与单体程序计算结果最大相对误差为1.65%,误差较小;2)瞬态验证中,入口流量正弦扰动工况下,出口流量波动在周期和相位上完全同步;3)不确定性量化表明冷却剂温度、包壳峰值温度等参数平均值位于95%置信区间内,标准差小,计算可信度高;4)灵敏度分析揭示出口压力和燃料棒热流密度对系统响应量影响较大,入口质量流量和包壳热导率分别对不同响应量产生显著的负向影响,研究结果验证了多尺度耦合系统在动态工况下的响应可靠性。 展开更多
关键词 preCICE开源耦合库 多尺度耦合 不确定性分析 子通道程序 CFD程序
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基于ASME规范的核一级承压设备强度校核及疲劳分析方法研究
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作者 姜炎明 李小畅 +2 位作者 田瑞峰 宋智广 谭思超 《核技术》 北大核心 2026年第2期120-129,共10页
反应堆一回路中部分管道长期承受冷热流体的交替冲刷,局部可能出现的热分层现象使管道中的热应力进一步加大,由此产生的应力集中及疲劳问题可能危害反应堆的安全运行。基于热流固多物理场耦合方法结合ASME(American Society of Mechanic... 反应堆一回路中部分管道长期承受冷热流体的交替冲刷,局部可能出现的热分层现象使管道中的热应力进一步加大,由此产生的应力集中及疲劳问题可能危害反应堆的安全运行。基于热流固多物理场耦合方法结合ASME(American Society of Mechanical Engineers)规范中适用于核一级承压设备的相关标准和分析流程,对某型号反应堆的管道系统开展了结构强度校核及疲劳分析,数值结果表明:当前工况参数及出现次数叠加作用下管道系统的应力分类结果满足规范要求,不会出现不可逆的结构损伤,且关键结构不连续位置的疲劳累积使用因子均小于1,未出现累积使用因子超限问题。 展开更多
关键词 ASME规范 热流固耦合 强度校核 疲劳分析 累积使用因子
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光热汽轮机转子热结构耦合应力预测及优化
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作者 李伟业 文思果 +3 位作者 丁莹 綦芮 袁奇 李浦 《西安交通大学学报》 北大核心 2026年第4期187-198,共12页
针对太阳能光热汽轮机中低压转子在冷态启动过程中的应力集中问题,通过有限元建模与混合残差编码网络(HRENet)相结合的方法,开展了瞬态热固耦合分析、应力预测及优化研究。首先,建立了转子有限元模型,模拟冷态启动工况。其次,提出一种新... 针对太阳能光热汽轮机中低压转子在冷态启动过程中的应力集中问题,通过有限元建模与混合残差编码网络(HRENet)相结合的方法,开展了瞬态热固耦合分析、应力预测及优化研究。首先,建立了转子有限元模型,模拟冷态启动工况。其次,提出一种新型HRENet模型,用于精准预测不同启动参数下转子应力集中点的应力。最后,通过启动优化与结构优化降低转子应力。其中,启动过程的划分和优化是基于初始温度、升速率、初始升温时间和温升率4个参数;结构优化则采用自适应多目标方法对转子中心打孔进行设计。研究结果表明:最大温度应力出现在第1级叶根槽倒圆角位置,这主要源于该区域的高温度梯度;与人工神经网络、卷积神经网络、残差神经网络和Transformer模型相比,HRENet的综合加载等效应力预测平均绝对误差分别降低了65.23%、78.01%、88.23%和85.65%,均方误差降低了82.13%、90.43%、98.94%和96.22%,从而显著提升了预测精度;启动优化结果发现,温升率对应力影响最大,同时启动时间缩短了23.08%,危险点应力降低了5.3%;结构优化后,第1级叶根槽倒圆角应力分别降低了33.33%和28.43%。该研究可为光热汽轮机转子的安全运行与优化设计提供有效方法。 展开更多
关键词 光热汽轮机转子 混合残差编码网络 热固耦合分析 启动优化 结构优化
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检测JavaScript类的内聚耦合Code Smell 被引量:5
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作者 黄子杰 陈军华 高建华 《软件学报》 EI CSCD 北大核心 2021年第8期2505-2521,共17页
Code Smell是软件程序中存在不良设计和不良实现的征兆.正确地检测和识别Code Smell可以指导软件重构,提高软件的可用性和可靠性.通过Code Smell的度量指标,可以量化软件的设计问题.JavaScript已成为最常用的编程语言之一,类是JavaScrip... Code Smell是软件程序中存在不良设计和不良实现的征兆.正确地检测和识别Code Smell可以指导软件重构,提高软件的可用性和可靠性.通过Code Smell的度量指标,可以量化软件的设计问题.JavaScript已成为最常用的编程语言之一,类是JavaScript的设计模式,优秀类的设计体现为高内聚和低耦合.现有关于JavaScript内聚耦合的Code Smell研究均在微观的层面,即函数和语句上进行.它们可以提供程序实现的重构建议,但无法分析内聚耦合相关的软件系统设计问题.针对FE、DC和Blob这3种类的内聚耦合Code Smell,提出一种JavaScript类的内聚耦合Code Smell检测方法JS4C.该方法基于静态分析,同时适用于客户端和服务端程序.它通过遍历软件系统中所有的类,利用源程序的文本相似度特征和结构特征,识别Code Smell并检测其强度.在结构特征检测中,JS4C使用了经扩展的对象类型推断及非严格的耦合分散度度量法NSCDISP,有效地降低了解释型语言的静态分析过程中,类型信息缺失对检测产生的影响.实验通过对6个开源项目的分析表明,JS4C对内聚耦合设计问题有良好的检测效果. 展开更多
关键词 code Smell JAVASCRIPT 内聚 耦合
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Study on cipher propertys of constant weight codes
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作者 Lin Bogang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第2期458-461,共4页
Constant weight code is an important error-correcting control code in communications. Basic structure of constant weight codes for some arriving at Johnson bound, A(n, 2u, w), is presented. Some correlative property... Constant weight code is an important error-correcting control code in communications. Basic structure of constant weight codes for some arriving at Johnson bound, A(n, 2u, w), is presented. Some correlative propertys of the codes, the solution of arriving at Johnson bound, and the results on the couple constant code and some constant weight codes are discussed. The conclusion is verified through four examples. 展开更多
关键词 constant weight code Johnson bound couple relation boundary property combination cipher.
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Irregular Segmented Region Compression Coding Based on Pulse Coupled Neural Network
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作者 MA Yi-de QI Chun-liang +2 位作者 QIAN Zhi-bai SHI Fei ZHANG Bei-dou 《Semiconductor Photonics and Technology》 CAS 2006年第2期110-116,130,共8页
An irregular segmented region coding algorithm based on pulse coupled neural network(PCNN) is presented. PCNN has the property of pulse-coupled and changeable threshold, through which these adjacent pixels with approx... An irregular segmented region coding algorithm based on pulse coupled neural network(PCNN) is presented. PCNN has the property of pulse-coupled and changeable threshold, through which these adjacent pixels with approximate gray values can be activated simultaneously. One can draw a conclusion that PCNN has the advantage of realizing the regional segmentation, and the details of original image can be achieved by the parameter adjustment of segmented images, and at the same time, the trivial segmented regions can be avoided. For the better approximation of irregular segmented regions, the Gram-Schmidt method, by which a group of orthonormal basis functions is constructed from a group of linear independent initial base functions, is adopted. Because of the orthonormal reconstructing method, the quality of reconstructed image can be greatly improved and the progressive image transmission will also be possible. 展开更多
关键词 Pulse coupled neural network SEGMENTATION Orthonormal basis Compression coding possible.
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Spin nature of genetic code
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作者 Alexander A. Tulub Vassily E. Stefanov 《Journal of Biophysical Chemistry》 2013年第2期52-57,共6页
Nature has developed codon as a tool to manipulate a two-electron spin symmetry (short-living electrons, forming a radical pair, arise from the Mg-bound nucleosidetriphosphate cleavage at the triplet/singlet (T/S) cro... Nature has developed codon as a tool to manipulate a two-electron spin symmetry (short-living electrons, forming a radical pair, arise from the Mg-bound nucleosidetriphosphate cleavage at the triplet/singlet (T/S) crossing), which permits or forbids further nucleotide synthesis (DNA/RNA) and the synthesis of proteins. The thesis is confirmed by conducting DFT:B3LYP (6-311G** basis set) computations (T/S potential energy surfaces) with the model system composed of the template (C-G-C-G-A nucleotide sequence) and the growing chain (G-C-G nucleotide sequence, DNA or RNA). The origin of codon is in hyperfine interaction between a single electron, transferred onto the template, and three 31P nuclei built into the phosphorus fragments of nucleotides. The nuclei, together with the polynucleotide structure, form a spiral twist that is homeomorphic to a triangle patch on the Poincare sphere. Each triangle has unique angle values depending on the nucleotide nature and their position in the codon. The patch tracing produces the Berry phase changing the electron spin orientation from “up” to “down”. The Berry phase accumulation proceeds around the (T/S) conical intersections (CIs). The CIs are a result of complementary recognition between nucleotide bases at distances exceeding the commonly accepted Watson-Crick pairing by 0.17 A. Upon changing spin symmetry, the DNA or RNA chain is allowed to elongate by attaching a newly coming nucleotide. Without complementary recognition between the bases, the chain stops its elongation. The Berry phase accumulation along the patch tracing explains the effect of Crick’s wobbling when the second nucleotide plays a primary role in recognition. The data is directly linked to creation of a quantum computing device. 展开更多
关键词 SPINTRONICS NUCLEOTIDES GENETIC code Quantum COMPUTATIONS Berry’s Phase HYPERFINE coupling
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Transient Flow Simulation for VVER-1000 Using MCNP6/ANSYS Codes
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作者 R.M.Refeat S.H.Abdel-Latif A.M.Refaey 《材料科学与工程(中英文A版)》 2021年第3期71-87,共17页
Investigating the time-dependent behavior of nuclear reactors during loss of flow accidents is necessary for safety assessment.Coupled neutronic/thermal-hydraulic codes are used to simulate a full three-dimensional mo... Investigating the time-dependent behavior of nuclear reactors during loss of flow accidents is necessary for safety assessment.Coupled neutronic/thermal-hydraulic codes are used to simulate a full three-dimensional model and predict the essential safety parameters.MCNP6/ANSYS-FLUENT17.2 coupled scheme is used in the present study to simulate a three-dimensional model for VVER-1000 assembly and analyze its behavior during a LOFA(loss of flow accident).Three LOFA scenarios are proposed to represent the failure of one,two or three of the coolant pumps.The influence of the accident on the reactivity and axial power distribution of the assembly is determined considering thermal-hydraulic feedbacks.Then the data obtained are provided to the thermal-hydraulic code to calculate the actual temperature values.The results of the study showed that the developed coupling scheme granted an actual and precise description of the axial behavior of the assembly during LOFA.The output data obtained from both neutronic and thermal-hydraulic calculations have a strong feedback effect;this demonstrated the effect of data exchange between codes to predict accurate values for the main safety parameters.Moreover,it revealed the importance of studying the detailed axial distribution of the safety parameters for the reactor assessment during accidents rather than taking average values in calculations. 展开更多
关键词 coupling codes MCNP6 ANSYS FLUENT LOFA
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Research on improving the data transmission reliability of anchor coupling chain
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作者 WANG Xiaorui ZHANG Xueling +2 位作者 GUO Yifeng WANG Rungeng WU Yongfang 《Marine Science Bulletin》 2025年第2期88-96,共9页
Advanced marine exploration technology is the key to rapidly acquiring reliable ocean information.Anchor coupling chain is one of the latest undersea exploration equipments.However,it is heavily influenced by channel ... Advanced marine exploration technology is the key to rapidly acquiring reliable ocean information.Anchor coupling chain is one of the latest undersea exploration equipments.However,it is heavily influenced by channel parameters,transmission technology,and marine noise,leading to severe signal attenuation,which greatly affects the reliability of signal transmission.The article introduces the current state of research and dynamic analysis of the development of anchor coupling chain,as well as its working principles.It addresses the main factors affecting the reliability of data transmission,such as narrow signal transmission channels,low signal-to-noise ratio,and complex marine noise.The article proposes solutions such as optimizing the magnetic ring materials and structures,using RS-CC encoding,and OFDM technology,providing research ideas for improving the data transmission reliability of Anchor coupling chain. 展开更多
关键词 anchor coupling chain data transmission reliability magnetic ring materials and structures RS-CC coding OFDM technology
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Low-Density Parity-Check Codes: Research Status and Development Direction
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作者 Jie Xu Zhiyong Zheng Kun Tian 《Journal of Information Security》 2022年第4期257-271,共15页
In this paper, we conclude five kinds of methods for construction of the regular low-density parity matrix H and three kinds of methods for the construction of irregular low-density parity-check matrix H. Through the ... In this paper, we conclude five kinds of methods for construction of the regular low-density parity matrix H and three kinds of methods for the construction of irregular low-density parity-check matrix H. Through the analysis of the code rate and parameters of these eight kinds of structures, we find that the construction of low-density parity-check matrix tends to be more flexible and the parameter variability is enhanced. We propose that the current development cost should be lower with the progress of electronic technology and we need research on more practical Low-Density Parity-Check Codes (LDPC). Combined with the application of the quantum distribution key, we urgently need to explore the research direction of relevant theories and technologies of LDPC codes in other fields of quantum information in the future. 展开更多
关键词 Low-Density Parity-Check (LDPC) Parity Check Matrix H Quasi-Cyclic (QC) LDPC Spatially coupled Low-Density Parity-Check (SC-LDPC) codes
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基于节点动态时序的空间耦合LDPC码滑窗译码
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作者 周华 徐辰辰 李子杰 《电讯技术》 北大核心 2025年第8期1315-1322,共8页
为提升基于原模图构造的空间耦合低密度奇偶校验(Spatially-Coupled Low-Density Parity-Check,SC-LDPC)码滑窗译码(Sliding Window Decoding,SWD)算法译码性能,提出了残差滑窗译码(Residual SWD,RSWD)算法,通过动态选择可靠度最低(残... 为提升基于原模图构造的空间耦合低密度奇偶校验(Spatially-Coupled Low-Density Parity-Check,SC-LDPC)码滑窗译码(Sliding Window Decoding,SWD)算法译码性能,提出了残差滑窗译码(Residual SWD,RSWD)算法,通过动态选择可靠度最低(残差值最大)的边信息优先传输,降低边信息无效更新次数,提高了译码性能。RSWD译码在窗口内易出现贪婪组和静默节点现象,导致译码误码率(Bit Error Rate,BER)恶化。为改善这一问题,提出了基于节点的残差滑窗译码(Node-wise RSWD,NW-RSWD)算法和消除静默节点残差滑窗译码(Eliminating Silent Node RSWD,ESN-RSWD)算法。NW-RSWD算法在译码过程中以变量节点为单位,动态更新窗口内最大残差所在边的变量节点。ESN-RSWD算法在译码过程中根据残差值大小,遍历更新窗口内每一个变量节点,使更多的信息参与到窗口译码,避免滑窗译码陷入局部区域更新。仿真结果表明,信噪比处于3~3.5 dB区间时,相较于SWD算法,NW-RSWD算法复杂度增加约15%,ESN-RSWD算法复杂度增加约25%。在窗口大小为8时,为了达到10-6误码率,相较于SWD算法,NW-RSWD算法提升约0.7 dB性能,ESN-RSWD算法提升约0.85 dB。在10-3误码率时,SWD算法、NW-RSWD算法和ESN-RSWD算法分别需要约50次、10次和8次迭代才能达到相同的误码性能。所提算法以增加较少计算复杂度为代价,降低了译码误码率,减少了译码平均迭代次数。 展开更多
关键词 空间耦合低密度奇偶校验码 滑窗译码 信息传递 节点残差算法 消除静默节点残差算法
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2020—2022年中国西部3次M_(S)≥6.0地震前电离层扰动 被引量:1
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作者 郭雨帆 刘江 杜晓辉 《大地测量与地球动力学》 北大核心 2025年第8期851-857,共7页
基于欧洲轨道测定中心(CODE)总电子含量(TEC)数据和张衡一号卫星电子密度(N_(e))数据,分析2020—2022年中国西部3次M_(S)≥6.0浅源地震(2020年伽师M_(S)6.4、2021年漾濞M_(S)6.4和2022年马尔康M_(S)6.0地震)前的电离层扰动现象。结果表... 基于欧洲轨道测定中心(CODE)总电子含量(TEC)数据和张衡一号卫星电子密度(N_(e))数据,分析2020—2022年中国西部3次M_(S)≥6.0浅源地震(2020年伽师M_(S)6.4、2021年漾濞M_(S)6.4和2022年马尔康M_(S)6.0地震)前的电离层扰动现象。结果表明,电离层异常集中在震前1周内,并且在伽师M_(S)6.4地震前5 d和2 d、漾濞M_(S)6.4地震前7 d和马尔康M_(S)6.0地震前6 d出现CODE TEC和张衡一号卫星Ne同步异常。这3次强震可能通过岩石圈-大气层-电离层耦合机理模型的地球化学和电磁波通道影响电离层,震前5~15 d内震源区附近出现地球化学、水位和电磁等地震前兆异常。 展开更多
关键词 中国西部 强震 code TEC 张衡一号卫星N_(e) 圈层耦合机理
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面向6G的速率兼容空间耦合LDPC码设计
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作者 王筝 方健 +1 位作者 朱敏 白宝明 《移动通信》 2025年第2期65-69,共5页
面向6G通信中的高可靠、低时延需求,提出了一种速率兼容的空间耦合LDPC码设计。SC-LDPC码具有逼近香农限的优异性能和结合滑窗译码能够达到的更低译码时延。然而,为了解决移动通信中码率灵活问题,提出了拆分QCLDPC码成SC-LDPC码的策略,... 面向6G通信中的高可靠、低时延需求,提出了一种速率兼容的空间耦合LDPC码设计。SC-LDPC码具有逼近香农限的优异性能和结合滑窗译码能够达到的更低译码时延。然而,为了解决移动通信中码率灵活问题,提出了拆分QCLDPC码成SC-LDPC码的策略,同时结合PEXIT算法优化所构造的SC-LDPC码的译码门限;为了兼容5G LDPC码,选取5G LDPC码作为QC-LDPC码,从而设计出了速率兼容的SC-LDPC码。仿真结果表明,所设计的码字在多个码率下误码率性能均优于5G LDPC码。 展开更多
关键词 码构造 速率兼容 空间耦合LDPC码
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空间耦合量子LDPC码的译码研究
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作者 石莎 张毅军 +4 位作者 朱高辉 程承坤 肖卓彦 王增斌 王云江 《电子学报》 北大核心 2025年第7期2222-2228,共7页
空间耦合量子LDPC(Spatially-Coupled Quantum Low-Density Parity-Check,SC-QLDPC)码在分布式量子计算体系中有着重要应用,然而如何实现相应的低时延高效译码是其在实际应用中面临的核心挑战.本文聚焦SCQLDPC码在滑窗译码过程中,由窗... 空间耦合量子LDPC(Spatially-Coupled Quantum Low-Density Parity-Check,SC-QLDPC)码在分布式量子计算体系中有着重要应用,然而如何实现相应的低时延高效译码是其在实际应用中面临的核心挑战.本文聚焦SCQLDPC码在滑窗译码过程中,由窗口译码错误传播引起的连锁反应对译码性能所造成的严重影响这一问题,针对适用于SC-QLDPC码的量子双窗口滑动译码算法提出了双窗口回溯优化译码策略,给出了译码过程中扩大窗口的性价比度量方法,讨论了在量子滑窗回溯时,选择最佳回溯窗口大小的策略.实验表明,本文提出的量子滑窗译码的回溯策略可以在译码复杂度和性能上实现优化均衡,解决了量子滑窗译码过程中由窗口大小的不当选择带来的错误传播所造成的译码性能显著下降的问题. 展开更多
关键词 量子计算 量子纠错 空间耦合码 滑窗译码 错误抑制 量子LDPC码
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