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2-UPU/UPR并联机构的运动/力传递性能分析 认领 引用
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作者 程芳 文杰 +1 位作者 马春生 贺阳涛 《机械设计与制造》 北大核心 2026年第5期353-357,共5页
提出一种新型过约束2-UPU/UPR并联机构,对此并联机构在工作过程中的运动性能进行研究。首先,对机构2-UPU/UPR建立运动螺旋,基于螺旋理论对机构进行自由度分析,用修正的G-K公式进行验证;紧接着对机构进行运动学反解的求解,绘制了机构的... 提出一种新型过约束2-UPU/UPR并联机构,对此并联机构在工作过程中的运动性能进行研究。首先,对机构2-UPU/UPR建立运动螺旋,基于螺旋理论对机构进行自由度分析,用修正的G-K公式进行验证;紧接着对机构进行运动学反解的求解,绘制了机构的工作空间;最后通过计算得出机构的输入运动螺旋、传递力螺旋及输出运动螺旋,分析了此机构的运动/力传递性能,绘制了LTI传递性能图谱。研究结果表明该并联机构在空间中具有两移一转三个自由度,工作空间形状规则,在Z=150mm与Z=180mm期间优质工作空间较大。为该机构的优化及实际应用提供了理论基础。 展开更多
关键词 2-UPU/UPR并联机构 螺旋理论 过约束 工作空间 运动/力传递性能
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Two-dimensional inversion of spectral induced polarization data using MPI parallel algorithm in data space 认领 引用 被引量：4
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作者 张志勇 谭捍东 +3 位作者 王堃鹏 林昌洪 张斌 谢茂笔 《Applied Geophysics》 SCIE CSCD 2016年第1期13-24,217,共12页
Traditional two-dimensional（2D） complex resistivity forward modeling is based on Poisson＇s equation but spectral induced polarization（SIP） data are the coproducts of the induced polarization（IP） and the electro... Traditional two-dimensional（2D） complex resistivity forward modeling is based on Poisson＇s equation but spectral induced polarization（SIP） data are the coproducts of the induced polarization（IP） and the electromagnetic induction（EMI） effects.This is especially true under high frequencies,where the EMI effect can exceed the IP effect.2D inversion that only considers the IP effect reduces the reliability of the inversion data.In this paper,we derive differential equations using Maxwell＇s equations.With the introduction of the Cole-Cole model,we use the finite-element method to conduct2 D SIP forward modeling that considers the EMI and IP effects simultaneously.The data-space Occam method,in which different constraints to the model smoothness and parametric boundaries are introduced,is then used to simultaneously obtain the four parameters of the Cole-Cole model using multi-array electric field data.This approach not only improves the stability of the inversion but also significantly reduces the solution ambiguity.To improve the computational efficiency,message passing interface programming was used to accelerate the 2D SIP forward modeling and inversion.Synthetic datasets were tested using both serial and parallel algorithms,and the tests suggest that the proposed parallel algorithm is robust and efficient. 展开更多
关键词 Spectral induced polarization 2D inversion data-space method Cole-Cole model MPI parallel computation
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Inverse Control of Cable-driven Parallel Mechanism Using Type-2 Fuzzy Neural Network 认领 引用 被引量：13
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作者 LI Cheng-Dong YI Jian-Qiang +1 位作者 YU Yi ZHAO Dong-Bin 《自动化学报》 EI CAS 北大核心 2010年第3期459-464,共6页
The level adjustment of cable-driven parallel mecha-nism is challenging due to the difficulty in obtaining an accurate mathematical model and the fact that different sources of un-certainties exist in the adjustment p... The level adjustment of cable-driven parallel mecha-nism is challenging due to the difficulty in obtaining an accurate mathematical model and the fact that different sources of un-certainties exist in the adjustment process.This paper presents a type-2 fuzzy neural network(T2FNN)based inverse control scheme for the level adjustment process.The T2FNN,whose consequent interval weights are trained by the iterative least squares estimation method,is used to approximate the inverse dynamics of the process and to handle uncertainties.Finally,the proposed control scheme and its counterpart type-1 fuzzy neural network based inverse control scheme--are compared and implemented for leveling the cable-driven parallel mechanism. 展开更多
关键词 Inverse control type-2 fuzzy logic neural network parallel mechanism
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Design and Analysis of a Novel 2T2R Parallel Mechanism with the Closed-loop Limbs 认领 引用 被引量：4
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作者 Hai-Rong Fang Peng-Fei Liu +1 位作者 Hui Yang Bing-Shan Jiang 《International Journal of Automation and computing》 CSCD 2021年第4期654-666,共13页
This paper presents a novel four degrees of freedom(DOF) parallel mechanism with the closed-loop limbs, which includes two translational(2 T) DOF and two rotational(2 R) DOF. By connecting the proposed parallel mechan... This paper presents a novel four degrees of freedom(DOF) parallel mechanism with the closed-loop limbs, which includes two translational(2 T) DOF and two rotational(2 R) DOF. By connecting the proposed parallel mechanism with the guide rail in series,the 5-DOF hybrid robot system is obtained, which can be applied for the composite material tape laying in aerospace industry. The analysis in this paper mainly focuses on the parallel module of the hybrid robot system. First, the freedom of the proposed parallel mechanism is calculated based on the screw theory. Then, according to the closed-loop vector equation, the inverse kinematics and Jacobian matrix of the parallel mechanism are carried out. Next, the workspace stiffness and dexterity analysis of the parallel mechanism are investigated based on the constraint equations, static stiffness matrix and Jacobian condition number. Finally, the correctness of the inverse kinematics and the high stiffness of the parallel mechanism are verified by the kinematics and stiffness simulation analysis, which lays a foundation for the automatic composite material tape laying. 展开更多
关键词 2T2R parallel mechanism close loop structure high stiffness kinematics analysis workspace
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侧装式两转两移混联轮腿式机构运动学分析与步态规划 认领 引用
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作者 韩涛 马春生 +2 位作者 苑鹏飞 王欢 高宇杰 《科学技术与工程》 EI 北大核心 2026年第3期962-969,共8页
针对复杂的地面环境,为提高轮腿式机器人的稳定性和承载能力,提出了一种两转两移混联腿机构,采用侧装并联结构作为主体部分,并对其运动性能进行仿真分析。设计采用(2-RRS-RPS)&R混联机构,基于螺旋理论,建立了机构的运动螺旋矩阵对... 针对复杂的地面环境,为提高轮腿式机器人的稳定性和承载能力,提出了一种两转两移混联腿机构,采用侧装并联结构作为主体部分,并对其运动性能进行仿真分析。设计采用(2-RRS-RPS)&R混联机构,基于螺旋理论,建立了机构的运动螺旋矩阵对自由度进行分析,并结合修正的Grübler-Kutzbach公式验证机构的自由度,求解机构的运动学逆解;以运动学的逆解为基础,绘制出可到达的活动空间;利用Adams软件模拟单腿动作,以验证模型成立的正确性;通过对移动机器人跨越障碍步态规划和仿真进一步确认其在复杂地形下的稳定性和运动能力。结果表明该机构运动性能良好,可满足运动和工作范围需求。 展开更多
关键词 2-RRS-RPS并联机构 螺旋理论 工作空间 步态规划
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GEE遥感特征混合优选提升高海拔树种分类精度 认领 引用 被引量：1
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作者 周赛 黄凯 +5 位作者 张加龙 王明星 滕晨凯 夏乐艳 姜新周 程滔 《北京林业大学学报》 CAS CSCD 北大核心 2026年第1期26-40,共15页
【目的】高海拔地区森林资源动态监测面临云雾干扰、训练样本匮乏及树种光谱相似性高等多重瓶颈,严重制约了优势树种空间分布的精准制图。本研究以香格里拉市典型纯林为对象,旨在利用多源遥感数据与多策略特征优选方法提升树种识别精度... 【目的】高海拔地区森林资源动态监测面临云雾干扰、训练样本匮乏及树种光谱相似性高等多重瓶颈,严重制约了优势树种空间分布的精准制图。本研究以香格里拉市典型纯林为对象,旨在利用多源遥感数据与多策略特征优选方法提升树种识别精度与模型泛化能力。【方法】研究基于GEE平台获取Sentinel-2光学时序、Sentinel-1雷达数据及SRTM地形数据,提取光谱、纹理、植被指数、雷达极化、地形及时序特征,构建基础特征集。采用随机森林(RF)模型确定特征优选前的最优方案后,并行J-M距离、ReliefF和RFE算法构建单一特征集,同时对这3种特征集进行并集融合构建并行混合特征集。将单一优选与并行混合特征集分别代入RF模型重新分类,对比优选前后方案确定最优分类方案。采用生产者精度(PA)、用户精度(UA)、调和平均值(F1)、总体精度(OA)和Kappa系数评价分类精度。【结果】(1)基于J-M距离、ReliefF和RFE并行混合的特征优选方案9精度最高(OA为94.82%,Kappa系数为0.94),优于特征优选前的最优方案5。(2)多源遥感数据协同分类效果优于单一数据源,仅使用Sentinel-2数据的OA为83.35%(Kappa系数0.79);依次引入Sentinel-1雷达特征、Sentinel-1的纹理特征、地形特征和Sentinel-2时序特征后,OA分别提升了0.87、6.28、8.08、10.18个百分点(Kappa系数分别为0.81、0.86、0.90、0.92),其中Sentinel-2时序特征的引入使分类精度提升了2.10个百分点。(3)植被指数时序曲线分析表明,优势树种在秋冬季节差异显著,可分离性强。【结论】基于GEE平台多源遥感数据协同J-M距离-ReliefF-RFE并行混合特征优选有效提升了香格里拉森林优势树种的识别精度,系统揭示了其空间分布格局,为高海拔地区森林资源的精准监测提供了技术支撑。 展开更多
关键词 树种分类 多源遥感数据 并行混合特征选择 Sentinel-2时序 Google Earth Engine(GEE) 随机森林(RF) 递归特征消除(RFE) J-M距离 香格里拉
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基于多目标优化的船舶柴油发电机组并网策略 认领 引用
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作者 韩健 丁宇 +3 位作者 陈斯文 刘国政 王瑞 随从标 《哈尔滨工程大学学报》 EI CAS CSCD 北大核心 2026年第2期407-415,490,共9页
为了研究一种高效且环保的邮轮柴油发电机组并网策略,本文构建以CO2排放、NOx排放和并网时间为多目标的优化模型,采用多目标遗传算法进行求解,并结合层次分析法与熵权法构建的综合权重TOPSIS方法,给出了典型负荷区间的最优并网调... 为了研究一种高效且环保的邮轮柴油发电机组并网策略,本文构建以CO2排放、NOx排放和并网时间为多目标的优化模型,采用多目标遗传算法进行求解,并结合层次分析法与熵权法构建的综合权重TOPSIS方法,给出了典型负荷区间的最优并网调度方案。研究结果表明所提出策略在中高负荷下的3个目标值显著优于传统下垂控制策略,在整个负荷区间内CO2与NOx排放分别平均降低3.01、1.29 g(kW·h),并网时间也显著缩减,且并网过程中机组转速波动率控制在0.3%以内。本研究表明基于多目标遗传算法的并网优化策略兼具环保性与动态响应优势,可为邮轮机组的并网控制策略设计提供理论支持与工程参考。 展开更多
关键词 多目标遗传算法 柴油发电机组并网 能量管理系统 船舶电力推进系统仿真 CO2排放 NOx排放 并网时间 转速波动率
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基于2-D-DPD的双频发射机互调失真与谐波抑制方法 认领 引用
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作者 陆燕辉 罗浩 +1 位作者 罗嘉 来晋明 《电子信息对抗技术》 2026年第3期106-112,共7页
针对并行双频发射机中的线性化问题,提出了一种基于二维预失真(2-D Digital Predistortion,2-D-DPD)技术的谐波抵消二维预失真(2-D Digital Predistortion of Harmonic Cancellation,HC-2-D-DPD)模型。传统的2-D-DPD技术能够有效抑制功... 针对并行双频发射机中的线性化问题,提出了一种基于二维预失真(2-D Digital Predistortion,2-D-DPD)技术的谐波抵消二维预失真(2-D Digital Predistortion of Harmonic Cancellation,HC-2-D-DPD)模型。传统的2-D-DPD技术能够有效抑制功率放大器输入端产生的带内互调失真,但对功率放大器产生的谐波失真和频带间互调失真却无能为力。现有的谐波抑制方法依赖滤波器组或数字谐波抑制技术,这些方法要么增加了硬件资源,要么忽略了频带间互调失真。通过理论分析和实验验证,证明了新模型在相同模型复杂度下,显著提高了对不同频点的谐波抑制能力,其中二次谐波抑制效果提升约29 dB,三次谐波抑制效果提升约33 dB。此外,HC-2-D-DPD模型在二阶互调失真(Second Order Intermodulation Distortion,IMD2)、三阶互调失真(IMD3)和四阶互调失真(IMD4)的抵消性能上,分别比2-D-DPD模型提高了约6.29 dB、3.57 dB和5.17 dB。实验结果表明,HC-2-D-DPD模型对解决并行双频发射机中的谐波失真和频带间互调失真的频谱增生问题具有良好效果。 展开更多
关键词 2-D-DPD 数字预失真 并行双频发射机 谐波抑制 交叉调制失真
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补气与平行压缩CO2跨临界制冷系统的性能对比分析 认领 引用
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作者 吕捷 张文婷 杨启超 《制冷与空调》 2026年第2期75-83,共9页
文章针对补气与平行压缩CO2跨临界制冷系统建立热力学分析数学模型,对比分析相对中间压力、气冷器出口温度和蒸发温度等工况参数对经济器、闪发器、经济器平行压缩和闪发平行压缩CO2跨临界制冷系统的性能影响规律。研究表明:在不... 文章针对补气与平行压缩CO2跨临界制冷系统建立热力学分析数学模型,对比分析相对中间压力、气冷器出口温度和蒸发温度等工况参数对经济器、闪发器、经济器平行压缩和闪发平行压缩CO2跨临界制冷系统的性能影响规律。研究表明:在不同的气冷器出口温度和蒸发温度下,4个系统均存在最佳的相对中间压力和最佳排气压力。补气系统比平行压缩系统有更高的COP值,更低的压缩机功耗和排气温度,而补气系统中的带闪发器的跨临界CO2制冷系统性能最佳。 展开更多
关键词 跨临界CO2制冷系统 经济器 平行压缩 热力学分析 性能系数
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Optimum Seeking of Redundant Actuators for M-RCM 3-UPU Parallel Mechanism 认领 引用 被引量：3
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作者 Chen Zhao Jingke Song +2 位作者 Xuechan Chen Ziming Chen Huafeng Ding 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第6期373-384,共12页
The singularity problem brings troubles to the design and application for the parallel mechanism.Currently,redun-dant actuation is one of the useful methods to solve this singularity problem.However,faced to the numer... The singularity problem brings troubles to the design and application for the parallel mechanism.Currently,redun-dant actuation is one of the useful methods to solve this singularity problem.However,faced to the numerous joints in a parallel mechanism,how to make a quantitative criterion of seeking the most efficient joints added actuators for letting the mechanism passes through singularity is a necessarily open issue.This paper focuses on a 2R1T 3-UPU(U for universal joint and P for prismatic joint)parallel mechanism(PM)with two rotational and one translational(2R1T)degrees of freedom(DOFs)and the ability of multiple remote centers of motion(M-RCM).The singularity analysis based on the indexes of motion/force transmissibility and constraint shows that this PM has transmission singular-ity,constraint singularity,mixed singularity and limb singularity.To solve these singular problems,the quantifiable redundancy transmission index(RTI)and the redundancy constraint index(RCI)are proposed for optimum seeking of redundant actuators for this PM.Then the appropriate redundant actuators are selected and the working scheme for redundant actuators near the corresponding singular configuration are given to help the PM passes through the singularity.This research proposes a quantitative criterion to optimum seeking of redundant actuators for the parallel mechanism to solve its singularity. 展开更多
关键词 Parallel mechanism 2R1T RCM Singularity Redundant actuation
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Motion Characteristics Analysis of a Novel Spherical Two-degree-of-freedom Parallel Mechanism 认领 引用 被引量：2
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作者 Ziming Chen Xuechan Chen +3 位作者 Min Gao Chen Zhao Kun Zhao Yanwen Li 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2022年第2期91-99,共9页
Current research on spherical parallel mechanisms(SPMs)mainly focus on surgical robots,exoskeleton robots,entertainment equipment,and other fields.However,compared with the SPM,the structure types and research content... Current research on spherical parallel mechanisms(SPMs)mainly focus on surgical robots,exoskeleton robots,entertainment equipment,and other fields.However,compared with the SPM,the structure types and research contents of the SPM are not abundant enough.In this paper,a novel two-degree-of-freedom(2DOF)SPM with symmetrical structure is proposed and analyzed.First,the models of forward kinematics and inverse kinematics are established based on D-H parameters,and the Jacobian matrix of the mechanism is obtained and verified.Second,the workspace of the mechanism is obtained according to inverse kinematics and link interference conditions.Next,rotational characteristics analysis shows that the end effector can achieve continuous rotation about an axis located in the mid-plane and passing through the rotation center of the mechanism.Moreover,the rotational characteristics of the mechanism are proved,and motion planning is carried out.A numerical example is given to verify the kinematics analysis and motion planning.Finally,some variant mechanisms can be synthesized.This work lays the foundation for the motion control and practical application of this 2DOF SPM. 展开更多
关键词 Spherical parallel mechanism 2DOF Workspace Equivalent rotation
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根皮苷氧化物POP2的酶促反应体系及其结构表征 认领 引用 被引量：3
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作者 王娟 邓红 +2 位作者 刘芸 郭玉蓉 孟永宏 《中国农业科学》 CAS CSCD 北大核心 2018年第1期182-190,共9页
【目的】根皮苷氧化物POP2是苹果汁加工过程中由酶促氧化生成的一种多酚氧化物,对果汁的褐变和劣变有着重要影响。通过多酚氧化酶氧化根皮苷反应体系的建立,POP2的分离纯化与结构表征,探讨根皮苷氧化物POP2合成条件与反应历程,为苹果汁... 【目的】根皮苷氧化物POP2是苹果汁加工过程中由酶促氧化生成的一种多酚氧化物,对果汁的褐变和劣变有着重要影响。通过多酚氧化酶氧化根皮苷反应体系的建立,POP2的分离纯化与结构表征,探讨根皮苷氧化物POP2合成条件与反应历程,为苹果汁中POP2的检测分析,及弄清其对果汁褐变和劣变的影响奠定基础。【方法】通过p H、温度、底物浓度3个单因素试验建立根皮苷酶促氧化体系的基础上,研究乙醇溶液对酶促反应的促进作用和反应历程,通过高效液相色谱法检测根皮苷酶促氧化过程中根皮苷、中间产物及POP2含量的变化,通过乙酸乙酯萃取、无水乙醇除盐、重结晶等方法对氧化产物POP2进行分离纯化,并采用质谱(ESI-MS)和红外光谱(IR)对POP2进行结构表征。【结果】根皮苷酶促氧化反应的最佳条件为p H 6.5、35℃、底物浓度3 mg·m L-1,添加不同浓度的无水乙醇均能显著提高根皮苷酶促氧化速率,当添加浓度为20%时,可提高反应转化率,最大为2.4倍;根皮苷反应液随时间的变化颜色也发生改变,反应刚开始溶液颜色呈微黄色,随着反应的进行颜色逐渐从亮黄色变为橙黄色,最终产物的颜色为橙红色;高效液相色谱法分析根皮苷酶促氧化反应历程发现,当底物浓度为3 mg·m L-1,反应48 h时,根皮苷的转化率最大为90.2%,中间产物X1和POP1也基本接近痕量,POP2的积累量基本不再发生变化;通过乙酸乙酯萃取可以将反应液中残留的根皮苷除去,用无水乙醇除盐并经甲醇重结晶后,获得纯度为96.8%的POP2;经正离子模式ESI-MS分析,POP2的m/z为467,分子式为C21H22O12;IR结果发现POP2具有特征性的醚、氧化羧基、酮基及苯环官能团,与推测的根皮苷氧化物结构式吻合。【结论】根皮苷酶促氧化体系中的主要氧化物为POP2,可以根据POP2的含量高低建立苹果汁褐变和劣变的标志性检测指标。 展开更多
关键词 果汁 根皮苷 氧化物POP2 酶促反应 结构表征
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Parallel-Dynamic Interpolation Algorithm of Sea Surface Height for Future 2D Altimetry Mapping of Sea Surface Height 认领 引用 被引量：1
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作者 DI Jiankai MA Chunyong CHEN Ge 《Journal of Ocean University of China》 SCIE CAS CSCD 2021年第5期1121-1135,共15页
The sea surface height data volume of the future wide-swath two-dimensional(2D)altimetric satellite is thousands of times greater than that of nadir altimetric satellites.The time complexity of the 2D altimetry mappin... The sea surface height data volume of the future wide-swath two-dimensional(2D)altimetric satellite is thousands of times greater than that of nadir altimetric satellites.The time complexity of the 2D altimetry mapping reaches O(n3).It is challenging to map the global grid products of future 2D altimetric satellites.In this study,to improve the efficiency of global data mapping,a new algorithm called parallel-dynamic interpolation(PA-DI)was designed.Through the use of 2D data segmentation and fine-grained data mosaic methods,the parallel along-track DI processes were accelerated,and a fast and efficient spatial-temporal high-resolution and low-error enhanced mapping method was obtained.As determined from a comparison of the single-threaded DI with the PA-DI,the new algorithm optimized the time complexity from O(n3)to O(n3/KL),which improved the mapping efficiency and achieved the expected results.According to the test results of the observing system simulation experiments,the PA-DI algorithm may provide an efficient and reliable method for future wide-swath 2D altimetric satellite mapping. 展开更多
关键词 parallel computation data segmentation data mosaic dynamic interpolation wide-swath 2D altimetric satellite
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Parallel discrete lion swarm optimization algorithm for solving traveling salesman problem 认领 引用 被引量：4
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作者 ZHANG Daoqing JIANG Mingyan 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2020年第4期751-760,共10页
As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optim... As a typical representative of the NP-complete problem, the traveling salesman problem(TSP) is widely utilized in computer networks, logistics distribution, and other fields. In this paper, a discrete lion swarm optimization(DLSO) algorithm is proposed to solve the TSP. Firstly, we introduce discrete coding and order crossover operators in DLSO. Secondly, we use the complete 2-opt(C2-opt) algorithm to enhance the local search ability.Then in order to enhance the efficiency of the algorithm, a parallel discrete lion swarm optimization(PDLSO) algorithm is proposed.The PDLSO has multiple populations, and each sub-population independently runs the DLSO algorithm in parallel. We use the ring topology to transfer information between sub-populations. Experiments on some benchmarks TSP problems show that the DLSO algorithm has a better accuracy than other algorithms, and the PDLSO algorithm can effectively shorten the running time. 展开更多
关键词 discrete lion swarm optimization(DLSO)algorithm complete 2-opt(C2-opt)algorithm parallel discrete lion swarm optimization(PDLSO)algorithm traveling salesman problem(TSP)
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MicroRNA引起mRNA降解关键核酸酶CAF1和POP2的生物进化分析 认领 引用
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作者 张凤娟 朴香花 +1 位作者 吴立刚 高必达 《生命科学研究》 CAS 2010年第6期492-498,共7页
MicroRNA(miRNA)参与调控高等真核生物中三分之一以上基因的表达,其中核酸酶CAF1(CCR4-associated factor 1)及其同源基因POP2在miRNA引发的mRNA 3′端多聚腺苷酸(poly(A))的脱腺苷酸化过程中起了关键作用.通过实时定量RT-PCR的方法检... MicroRNA(miRNA)参与调控高等真核生物中三分之一以上基因的表达,其中核酸酶CAF1(CCR4-associated factor 1)及其同源基因POP2在miRNA引发的mRNA 3′端多聚腺苷酸(poly(A))的脱腺苷酸化过程中起了关键作用.通过实时定量RT-PCR的方法检测了小鼠各个组织中CAF1和POP2的相对表达情况,发现CAF1和POP2的组织分布特征不同.大多数组织中CAF1的表达水平明显高于POP2,并且组织间差异很大,特别是在大脑、小脑以及睾丸组织中CAF1的表达量很高,而POP2的表达量和变化幅度都较低.蛋白质序列比对发现,CAF1和POP2是一类进化过程中高度保守的核酸外切酶,在酵母、线虫、果蝇和尾索动物代表物种海鞘中都只存在单一基因,而进化到鱼类后产生了两个同源基因——CAF1和POP2,其中CAF1的氨基酸序列保守性较POP2更高,更加接近于原始的单一序列.CAF1和POP2这一对同源基因氨基酸序列的主要差别在蛋白质的C端.鱼类中POP2的C端序列同CAF1的序列较为接近,而在爬行动物之后POP2产生了与CAF1具有明显差异的C端序列,并逐渐趋于稳定.我们的分析结果同已有的功能研究一致,表明可能在miRNA产生后的进化过程中产生了CAF1和POP2两个同源基因,其中CAF1主要担负miRNA调控mRNA脱腺苷酸化的功能,而POP2可能主要参与其它不同的调控作用。 展开更多
关键词 microRNA 脱腺苷酸化 CAF1 POP2 进化分析
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Parallel numerical simulation on CO2 geologic storage in Ordos Basin, China 认领 引用
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作者 LEI Honglei ZHANG Yanjun +4 位作者 WU Fan HU Zhongjun YU Ziwang ZHU Chengcheng LU Tianqi 《Global Geology》 2017年第3期164-169,共6页
The authors developed a 3-D numerical injection model on parallel TOUGH2-FLAC3 D based on the site-specific stratigraphic information in Ordos Basin to simulate the Shenhua CO_2 geological storage( CGS)demonstration p... The authors developed a 3-D numerical injection model on parallel TOUGH2-FLAC3 D based on the site-specific stratigraphic information in Ordos Basin to simulate the Shenhua CO_2 geological storage( CGS)demonstration project injection process for three years and forecast CO_2 migration and layers displacement after injection for seven years. The results suggested that CO_2 migration did not stop after three years of consecutive injection,but migration rate was slowing down with time. As a result,displacement near injection well increased with injection and decreased slowly after injection. The maximum displacement of surface center occurred near the end of injection,which was only 1. 24 cm. According to the displacement result,it is safe to continue injecting for this project. 展开更多
关键词 CGS Parallel numerical simulation CO2 migration surface displacement Ordos Basin
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A study on Parallel Computation Based on Finite Element Forward Modeling of 2D Magnetotelluric 认领 引用 被引量：1
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作者 Mao Wang Handong Tan +2 位作者 Changhong Lin Xiao Liu Zhiyong Zhang 《International Journal of Geosciences》 CAS 2015年第8期863-868,共6页
Magnetotelluric sounding method based on the difference of the rock’s resistivity is an exploration method about doing research in earth’s resistivity and phase using the native electromagnetic field. The paper adop... Magnetotelluric sounding method based on the difference of the rock’s resistivity is an exploration method about doing research in earth’s resistivity and phase using the native electromagnetic field. The paper adopts 2D finite element method as the magnetotelluric forward method and calculates the total field by primary field (also named background field) plus secondary field. We can?get more accurate forward result through the finite element method and we can get the result effected by the dense degree of grid slightly by the total field. But the method is not effective?enough when the model is divided into relative big grid. When the frequency changes, program solves relevant equation separately. According to the feature of the algorithm, we apply MPI parallel method in the algorithm. Every process solves relevant equation. The account of frequency?that a process needs to solve in parallel computation is less than the account that the process?needs to solve in serial algorithm. We can see that the forward result is the same with the serial algorithm and proves the correctness of algorithm. We do statistics about the efficiency of the parallel algorithm. When the account of processes is from 2 to 8, the speedup is from 1.63 to 2.64. It proves the effectiveness of the parallel algorithm. 展开更多
关键词 Magnetotelluric 2D Forward Modeling Finite Element Parallel Algorithm Total Field
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Second Order Parallel Tensors on Quasi-constant Curvature Manifolds 认领 引用
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作者 贾兴琴 《Chinese Quarterly Journal of Mathematics》 2002年第2期101-105,共5页
The author establishes in this paper the following results: (1) In a quasiconstant curvature manifold M a parallel tensor of type is constant multiple of the metric tensor. (2) On a quasi_constant curvature manifo... The author establishes in this paper the following results: (1) In a quasiconstant curvature manifold M a parallel tensor of type is constant multiple of the metric tensor. (2) On a quasi_constant curvature manifold there is no nonzero parallel 2_form. Unless the Ricci principal curvature corresponding to the generator of M is equal to zero. 展开更多
关键词 quasi_consttant curvature manifold second order parallel tensor parallel 2_form
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R22FFT算法的FPGA硬件结构优化设计与实现 认领 引用 被引量：1
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作者 肖海林 杨昱东 +4 位作者 杨紫伊 刘海龙 王玉 张中山 戴晓明 《计算机应用》 CSCD 北大核心 2025年第8期2637-2645,共9页
针对快速傅里叶变换(FFT)算法处理大规模数据时因消耗大量资源和时间而导致运算速度慢的问题,提出一种基22快速傅里叶变换(R22FFT)算法的现场可编程门阵列(FPGA)硬件结构优化设计与实现方法。首先,采用R22FFT算法构建一种序列... 针对快速傅里叶变换(FFT)算法处理大规模数据时因消耗大量资源和时间而导致运算速度慢的问题,提出一种基22快速傅里叶变换(R22FFT)算法的现场可编程门阵列(FPGA)硬件结构优化设计与实现方法。首先,采用R22FFT算法构建一种序列转换功能与流水线结构相结合的Y形双并行阵列结构,在有效降低硬件乘法器使用数量的同时,增大硬件结构的吞吐量,提高FFT算法在FPGA上的运算速度;其次,通过在R22FFT流水线的单级运算中利用旋转因子的相关特性,优化片上存储的资源消耗,使存储空间降低约50.00%;最后,在完成N点R22FFT算法结构优化的基础上,进一步提高硬件结构的可扩展性,即实现2N点和4N点的扩展运算。采用Verilog HDL语言完成硬件设计,并通过Modelsim仿真,使用Vivado2018.3软件将所提方法综合并布局布线,并分析所提方法的性能。实验结果表明,与4种改进的FFT硬件实现方法的运算时间相比,所提方法的运算时间分别降低了75.10%、95.34%、38.49%和49.20%,可见所提方法显著提高了运算速度。同时,所提方法资源消耗适中,消耗占比低,且具有运行功耗低以及可扩展性强的特点。 展开更多
关键词 Y形双并行阵列结构 现场可编程门阵列 基22快速傅里叶变换 多路径延迟交叉结构流水线 蝶形运算
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Multicore Parallel Implementation of 2D-FFTBased on TMS320C6678 DSP 认领 引用
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《信息工程期刊（中英文版）》 2015年第3期61-66,共6页
We put forward a multicore parallel plan for 2D-FFT and implement it on TMS320C6678 DSP after we research thecharacteristics of different multicore DSP programming models and two-dimension FFT （2D-FFT）. We bring the... We put forward a multicore parallel plan for 2D-FFT and implement it on TMS320C6678 DSP after we research thecharacteristics of different multicore DSP programming models and two-dimension FFT （2D-FFT）. We bring the parallelcomputing capability of multicore DSP into full play and improve working efficiency of 2D-FFT. It has hugely referential valuein implementing image processing arithmetic based on 2D-FFT. 展开更多
关键词 Multicore DSP Parallel Programming 2D-FFT Inter-Processor Communication
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