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MODE SPACE SMOOTHING ALGORITHM TO ESTIMATE DOA OF COHERENT SIGNALS IMPINGING ON UNIFORM CIRCULAR ARRAY 被引量:1
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作者 Ma Changlin Peng Yingning Tian Lisheng Liu Jianhua(Department of Electronic Engineering, Tsinghua University, Beijing 100084) 《Journal of Electronics(China)》 1998年第4期289-295,共7页
A novel method to estimate DOA of coherent signals impinging on a uniform circular array( UCA) is presented in this paper. A virtual uniform linear array (VULA) is first derived by using spatial DFT technique, transfo... A novel method to estimate DOA of coherent signals impinging on a uniform circular array( UCA) is presented in this paper. A virtual uniform linear array (VULA) is first derived by using spatial DFT technique, transforming the UCA from element space to phase mode space to obtain the properties of ordinary ULA, and then the well known spatial smoothing technique is applied to the VULA so that the lost rank of covariance matrix due to signal coherence can be retrieved. This method makes it feasible to use the simple MUSIC algorithm to estimate DOA of coherent signals impinging on a UCA without heavy computation burden. Simulation results strongly verify the effectiveness of the algorithm. 展开更多
关键词 mode space Virtual uniform linear array Spatial SMOOTHING
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Close-space modes in shock dynamic analysis 被引量:4
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作者 贺少华 吴新跃 +1 位作者 万强 谢最伟 《海军工程大学学报》 CAS 北大核心 2011年第5期31-35,共5页
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Separation of closely spaced modes by combining complex envelope displacement analysis with method of generating intrinsic mode functions through filtering algorithm based on wavelet packet decomposition 被引量:3
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作者 Y.S.KIM 陈立群 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第7期801-810,共10页
One of the important issues in the system identification and the spectrum analysis is the frequency resolution, i.e., the capability of distinguishing between two or more closely spaced frequency components. In the mo... One of the important issues in the system identification and the spectrum analysis is the frequency resolution, i.e., the capability of distinguishing between two or more closely spaced frequency components. In the modal identification by the empirical mode decomposition (EMD) method, because of the separating capability of the method, it is still a challenge to consistently and reliably identify the parameters of structures of which modes are not well separated. A new method is introduced to generate the intrin- sic mode functions (IMFs) through the filtering algorithm based on the wavelet packet decomposition (GIFWPD). In this paper, it is demonstrated that the CIFWPD method alone has a good capability of separating close modes, even under the severe condition beyond the critical frequency ratio limit which makes it impossible to separate two closely spaced harmonics by the EMD method. However, the GIFWPD-only based method is impelled to use a very fine sampling frequency with consequent prohibitive computational costs. Therefore, in order to decrease the computational load by reducing the amount of samples and improve the effectiveness of separation by increasing the frequency ratio, the present paper uses a combination of the complex envelope displacement analysis (CEDA) and the GIFWPD method. For the validation, two examples from the previous works are taken to show the results obtained by the GIFWPD-only based method and by combining the CEDA with the GIFWPD method. 展开更多
关键词 empirical mode decomposition (EMD) wavelet packet decomposition com- plex envelope displacement analysis (CEDA) closely spaced modes modal identification
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Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes 被引量:5
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作者 Jia Yinghong Xu Shijie 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2016年第3期688-703,共16页
An adaptive sliding mode control (ASMC) law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot. Each joint of the system is a free ball joint capable of rotating with th... An adaptive sliding mode control (ASMC) law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot. Each joint of the system is a free ball joint capable of rotating with three degrees of freedom (DOF). A cluster of control moment gyroscopes (CMGs) is mounted on each link and the base to actuate the system. The modified Rodrigues parameters (MRPs) are employed to describe the angular displacements, and the equations of motion are derived using Kane's equations. The controller for each link or the base is designed sep- arately in decentralized scheme. The unknown disturbances, inertia parameter uncertainties and nonlinear uncertainties are classified as a "lumped" matched uncertainty with unknown upper bound, and a continuous sliding mode control (SMC) law is proposed, in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty. A gen- eral amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input. Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov's method. Simulation results based on a three-link system verify the effectiveness of the proposed controller. 展开更多
关键词 Adaptation law Ball joint Control moment gyroscopes Sliding mode control space robot Trajectory tracking
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EXPLORATION OF SUBSTITUTION OF REPEATED MODE SUBSPACES FOR CLOSELY SPACED MODE SUBSPACES
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作者 徐博侯 鲍荣浩 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 1996年第1期65-72,共8页
A new quantitative concept is introduced in this paper, which may be used to facilitate the measurement of the controllability of a subspace similar to subspace controllability degree. Then the concrete form of the su... A new quantitative concept is introduced in this paper, which may be used to facilitate the measurement of the controllability of a subspace similar to subspace controllability degree. Then the concrete form of the subspace controllability degree of a flexible structure is derived, and the errors of subspace controllability degree and dynamical response caused by the substitution of a repeated mode subspace for a closely spaced mode subspace are discussed. All the results show that this substitution is rational under some conditions. 展开更多
关键词 flexible structure controllability degree closely spaced mode subspace repeated mode subspace
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Adaptive sliding mode backstepping control for near space vehicles considering engine faults 被引量:5
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作者 ZHAO Jing JIANG Bin +2 位作者 XIE Fei GAO Zhifeng XU Yufei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第2期343-351,共9页
A fault tolerant control methodology based adaptive sliding mode(ASM) backstepping is proposed for near space vehicle(NSV) attitude control system under engine faults. The proposed scheme combined adaptive backsteppin... A fault tolerant control methodology based adaptive sliding mode(ASM) backstepping is proposed for near space vehicle(NSV) attitude control system under engine faults. The proposed scheme combined adaptive backstepping with the sliding mode control strategy could guarantee the system’s stability and track desired signals under external disturbances and engine faults. Firstly, attitude mode description and the engine faulty model are given. Secondly, a nominal control law is designed.Thirdly, a sliding mode observer is given later in order to estimate both the information of engine faults and external disturbances. An adaptive sliding mode technology based on the previous nominal control law is developed via updating faulty parameters. Finally,analyze the system’s fault-tolerant performance and reliability through experiment simulation, which verifies the proposed design of fault-tolerant control can tolerate engine faults, as well as the strong robustness for external disturbance. 展开更多
关键词 fault tolerant control adaptive sliding mode(ASM) engine fault near space vehicle(NSV)
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Feedback Attitude Sliding Mode Regulation Control of Spacecraft Using Arm Motion
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作者 SHI Ye LIANG Bin +2 位作者 XU Dong WANG Xueqian XU Wenfu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第5期873-880,共8页
The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields.Most of the solutions of the manipulator’s motion trackin... The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields.Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance,so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints.Thus,sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process.Due to the switching effects of the variable structure controller,once the tracking error reaches the designed hyper-plane,it will be restricted to this plane permanently even with the existence of external disturbances.Thus,precise attitude regulation can be achieved.Furthermore,taking the non-zero initial tracking errors and chattering phenomenon into consideration,saturation functions are used to replace sign functions to smooth the control torques.The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller.Mathematical models of free-floating space manipulator are established and simulations are conducted in the end.The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm,the steady state error is 0.000 2 rad.In addition,the joint tracking trajectory is smooth,the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input.The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion,and improves the precision of the spacecraft attitude regulation. 展开更多
关键词 attitude regulation space robot trajectory tracking sliding mode control
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Robust chattering-free sliding mode control of space robot in task space
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作者 Baomin FENG Guangcheng MA Qiyong WEN Changhong WANG 《控制理论与应用(英文版)》 EI 2008年第2期146-152,共7页
This paper studies the tracking control problem of a free-floating space robot in a task space. Considering the model uncertainties and external disturbance, a robust sliding mode controller is proposed using the Lyap... This paper studies the tracking control problem of a free-floating space robot in a task space. Considering the model uncertainties and external disturbance, a robust sliding mode controller is proposed using the Lyapunov direct method and dissipative theory. To eliminate the chattering phenomenon, an radial basis function (RBF) neural network is applied to replace the discontinuous part of the control signal. A novel on-line learning method of the weights and parameters of the RBF neural network established using Lyapunov function assures the stability of the system. It is proved that the proposed controller can guarantee that the L2 gain from disturbance to tracking error is lower than the given index y. Simulation results show that the control method is valid. 展开更多
关键词 space robot Tracking control Sliding mode control Neural network
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浅海声源深度判决的正交子空间方法
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作者 王燕 朱文博 +2 位作者 王晋晋 邹男 梁国龙 《声学学报》 北大核心 2026年第1期110-118,共9页
针对浅水环境中的水面水下目标分辨问题,提出一种基于正交子空间的深度判决方法。通过凸优化方法对陷波子空间进行预处理,以去除干扰项提高子空间能量的估计精度。使用Schimidt正交构建正交的陷波分量和自由分量子空间,保留了完整的模... 针对浅水环境中的水面水下目标分辨问题,提出一种基于正交子空间的深度判决方法。通过凸优化方法对陷波子空间进行预处理,以去除干扰项提高子空间能量的估计精度。使用Schimidt正交构建正交的陷波分量和自由分量子空间,保留了完整的模态空间以增加参与判决的模态信息。通过仿真分析了信噪比和垂直孔径对各方法性能的影响,结果表明所提方法在阵列垂直孔径较小时的深度判决性能优于作为对比方法的匹配子空间判决器和基于正则最小二乘的模态滤波器。最后,利用浅海实验获得的数据对该方法进行了验证。数据结果表明,信噪比为7~16 dB时,在阵列孔径为0.16倍环境水深的情况下,所提方法仍可实现对水面和水下目标的分辨,正确分辨率高于对比方法。 展开更多
关键词 声源深度判决 正交子空间 Schimidt正交 模态空间
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Effect of Row Spacing Configuration Modes on Growth and Development of Xinluzao 63 and Amount of Residual Film in Agricultural Fields
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作者 Na LIU Wushiken +3 位作者 Honghao ZHANG Xia YAN Huzi CONG Lin LI 《Plant Diseases and Pests》 2025年第1期20-23,33,共5页
[Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the ... [Objectives]To provide a reference for the promotion of appropriate row spacing configuration modes for cotton planting in the Bortala Mongol Autonomous Prefecture of Xinjiang.[Methods]Xinluzao 63 was employed as the research subject to examine the effects of three different configuration modes:three rows with one film,four rows with one film,and six rows with one film,on the growth and development of cotton,as well as on yield and the amount of residual film in the field.[Results]In comparison to the configuration modes of four rows with one film and six rows with one film,the development process in the row spacing configuration mode of three rows with one film was accelerated by 1-4 d.This configuration mode exhibited variability in several agronomic traits,particularly in plant height,the number of fruiting branches per plant,and the number of leaves per plant,with the observed trend indicating T3>T2>T1.Conversely,the height of the first fruiting branch node displayed an inverse trend.In terms of yield composition,no significant differences were observed in boll weight and yield among various configuration modes.However,T3 exhibited the highest boll weight at 5.68 g and a yield of 462.67 kg/667 m 2.Additionally,significant differences were noted in harvesting density and the number of bolls per plant.T3 demonstrated the lowest harvesting density at 1.11×104 plants/666.7 m 2,the highest number of bolls per plant at 8.63,and the highest boll opening rate at 97.48%.Furthermore,T3 also resulted in the least amount of agricultural film residue during the current season.[Conclusions]Among the three planting configuration modes examined,the low-density planting configuration mode consisting of three rows and one film demonstrated a significant advantage at the individual plant level.This approach yielded results comparable to those of the high density planting configuration mode while also reducing costs.Furthermore,low density planting positively influenced the cotton boll opening rate,leading to a decreased amount of residual film and promoting ecological health within the agricultural land. 展开更多
关键词 COTTON Row spacing configuration mode Growth and development YIELD Amount of residual film
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Fiber transmission demonstrations in vector mode space division multiplexing 被引量:2
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作者 Leslie A. RUSCH Sophie LAROCHELLE 《Frontiers of Optoelectronics》 EI CSCD 2018年第2期155-162,共8页
Much attention has been focused on the use of scalar modes for space division multiplexing (SDM). Alternative vector mode bases offer another solution set for SDM, expanding the available trade-offs in system perfor... Much attention has been focused on the use of scalar modes for space division multiplexing (SDM). Alternative vector mode bases offer another solution set for SDM, expanding the available trade-offs in system performance and complexity. We present two types of ring core fiber conceived and designed to explore SDM with fibers exhibiting low interactions between supported modes. We review demonstrations of fiber data transmis- sion tbr two separate vector mode bases: one for orbital angular momentum (OAM) modes and one for linearly polarized vector (LPV) modes. The OAM mode demon- strations include short transmissions using commercially available transceivers, as well as kilometer length transmission at extended data rates. The LPV demonstra- tions span kilometer length transmissions at high data rate with coherent detection, as well as a radio over fiber experiment with direct detection of narrowband signals. 展开更多
关键词 space division multiplexing (SDM) few-mode fiber (FMF) orbital angular momentum (OAM) linearly polarized vector (LPV) modes ring core fiber(RCF) polarization maintaining fiber
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基于dSPACE的新型双滑模PMSM控制方法 被引量:4
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作者 高雅 刘卫国 骆光照 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2015年第6期2036-2043,共8页
设计一种基于滑模理论的永磁同步电机控制系统,利用滑模控制器代替传统的PID控制器,用滑模观测器代替传统的位置传感器。滑模控制器中针对传统滑模控制的抖振问题,引入准滑模和趋近律的概念,设计一种新的滑模控制器。滑模观测器使用连... 设计一种基于滑模理论的永磁同步电机控制系统,利用滑模控制器代替传统的PID控制器,用滑模观测器代替传统的位置传感器。滑模控制器中针对传统滑模控制的抖振问题,引入准滑模和趋近律的概念,设计一种新的滑模控制器。滑模观测器使用连续饱和函数代替传统的开关函数,有效地减少高频噪声信号,经李亚普诺夫稳定方程证明系统的稳定性。本设计方法充分发挥滑模控制的优势。通过d SPACE实验平台的验证和Control Desk环境的实时观测,证明所设计的新的滑模控制器在消除抖振和抗干扰方面明显优于传统的滑模控制器和PID控制器,滑模观测器能准确地观测位置信号,而且针对具有噪声干扰的场合,加入卡尔曼滤波器,有效地减少了干扰信号。 展开更多
关键词 永磁同步电机 滑模变结构 SVPWM 卡尔曼滤波器 硬件仿真 Dspace
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从“标准教室”到“教学单元群”:中小学空间设计的文化重构与范式转型——基于空间设计的创新模式研究
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作者 潘雯婷 钱锡栋 +1 位作者 徐佳 张艺 《建筑与文化》 2026年第1期170-172,共3页
文章批判性审视了传统教育语境下“标准教室”空间范式的局限性,创新性地提出“教学单元群”这一空间新模型,以此回应素质教育深化与课程改革推进的时代需求。通过系统的理论构建、典型案例解析与模式创新探索,文章深入论证了该模型如... 文章批判性审视了传统教育语境下“标准教室”空间范式的局限性,创新性地提出“教学单元群”这一空间新模型,以此回应素质教育深化与课程改革推进的时代需求。通过系统的理论构建、典型案例解析与模式创新探索,文章深入论证了该模型如何依托空间重构打破物理边界、借助功能复合激活多元场景、通过文化浸润与技术赋能释放空间潜力,从而突破传统教育空间的结构性困境,最终重塑“空间—教学—文化”三位一体的协同发展教育生态。此项研究致力于为中小学建筑空间的创新设计,提供兼具人文温度与科学理性的可操作空间范式,为教育空间的迭代升级注入新的思路与活力。 展开更多
关键词 教学区 单元空间 组合方式
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Observer-based control for the platform of a tethered space robot 被引量:2
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作者 Guang ZHAI Heming ZHENG Bo ZHANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2018年第8期1786-1796,共11页
This paper addresses the attitude control problem of a space tethered robot platform in the presence of unknown external disturbance caused by a connecting elastic tether. The tethergenerated unknown disturbance leads... This paper addresses the attitude control problem of a space tethered robot platform in the presence of unknown external disturbance caused by a connecting elastic tether. The tethergenerated unknown disturbance leads to tremendous challenges for attitude control of the platform.In this work, the perturbed attitude dynamics of the platform are derived with a consideration of the libration of the elastic tether, and then with the purpose of compensating the unknown disturbance, major attention is dedicated to develop a nonlinear disturbance observer based on gyros measurements, after which, an adaptive attitude scheme is proposed by combining the disturbance observer with a sliding mode controller. Finally, benefits from the observer based on an adaptive controller are validated by series of numerical simulations. 展开更多
关键词 Adaptive control Attitude dynamics Disturbance observerSliding mode controlTethered space robot
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基于Dual-Mode MMA+MDD双模式T/2分数间隔盲均衡算法的研究 被引量:1
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作者 柳雷 赖惠成 贾振红 《光子学报》 EI CAS CSCD 北大核心 2011年第6期898-901,共4页
均衡技术是用来解决通信系统中码间干扰的常用方法.针对传统恒模算法的收敛速度和稳态剩余码间干扰大的缺点,将双模式多模算法和改进型判决引导算法结合起来,并且应用于分数间隔盲均衡器中.该算法初期用双模式算法收敛均衡器,然后切换... 均衡技术是用来解决通信系统中码间干扰的常用方法.针对传统恒模算法的收敛速度和稳态剩余码间干扰大的缺点,将双模式多模算法和改进型判决引导算法结合起来,并且应用于分数间隔盲均衡器中.该算法初期用双模式算法收敛均衡器,然后切换到改进型判决引导算法中进一步收敛,由于分数间隔均衡器解决了波特间隔均衡器因抽样率不高带来的频谱混叠问题,从而进一步地提高了均衡效果.蒙特卡罗仿真表明,该算法不仅收敛速度快,而且得到较低的剩余码间干扰. 展开更多
关键词 恒模算法 盲均衡 分数间隔 双模式多模算法
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Concept Design,Modeling and Station-keeping Attitude Control of an Earth Observation Platform 被引量:2
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作者 YANG Yuenen WU Jie ZHENG Wei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第6期1245-1254,共10页
The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynam... The stratosphere airship provides a unique and promising platform for earth observation. Researches on the project design and control scheme for earth observation platforms are still rarely documented. Nonlinear dynamics, model uncertainties, and external disturbances contribute to the difficulty in maneuvering the stratosphere airship. A key technical challenge for the earth observation platform is station keeping, or the ability to remain fixed over a geo-location. This paper investigates the conceptual design, modeling and station-keeping attitude control of the near-space earth observation platform. A conceptual design of the earth observation platform is presented. The dynamics model of the platform is derived from the Newton-Euler formulation, and the station-keeping control system of the platform is formulated. The station-keeping attitude control approach for the platform is proposed. The multi-input multi-output nonlinear control system is decoupled into three single-input single-output linear subsystems via feedback linearization, the attitude controller design is carried out on the new linear systems using terminal sliding mode control, and the global stability of the closed-loop system is proven by using the Lyapunov theorem. The performance of the designed control system is simulated by using the variable step Runge-Kutta integrator. Simulation results show that the control system tracks the commanded attitude with an error of zero, which verify the effectiveness and robustness of the designed control system in the presence of parametric uncertainties. The near-space earth observation platform has several advantages over satellites, such as high resolution, fast to deploy, and convenient to retrieve, and the proposed control scheme provides an effective approach for station-keeping attitude control of the earth observation platform. 展开更多
关键词 earth observation platform novel design attitude control terminal sliding mode station keeping near-space
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数据空间建设的实践进展与运营模式分析——基于Data Spaces Radar的案例 被引量:14
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作者 夏义堃 程铄 +1 位作者 王雪 钱锦琳 《图书与情报》 CSSCI 北大核心 2024年第2期18-32,共15页
数据空间建设为数据要素的价值实现提供了可资借鉴的实践经验,全面解析其实践进展与运营模式,有助于破解数据流通的现实堵点、拓展数据利用的发展思路。文章首先将结构主义分析方法中的案例研究法作为主要研究方法,综合运用文献调研、... 数据空间建设为数据要素的价值实现提供了可资借鉴的实践经验,全面解析其实践进展与运营模式,有助于破解数据流通的现实堵点、拓展数据利用的发展思路。文章首先将结构主义分析方法中的案例研究法作为主要研究方法,综合运用文献调研、比较分析等方法,以Data Spaces Radar为案例来源,从实践进展、运营模式、核心要素等维度提炼数据空间建设特征。其次,在制度与技术的双轮驱动下,数据空间建设秉持制度规范统一性、技术设计整体性和治理模式协同性的架构原则,并按照产业思维、底线思维、信任思维、链式思维、集约思维的底层逻辑,形成较为完整的运营体系。未来应着力探索和解决数据空间视域下的数据资源价值化开发路径,针对数据流通堵点、利用痛点及信任难点问题,从体制机制、政策框架与技术应用等角度为推进我国的数据要素流通利用提供有益参考。 展开更多
关键词 数据空间 数据流通利用 数据自主权 运营模式 数据信任
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A UNIVERSAL MATRIX PERTURBATION TECHNIQUE FOR COMPLEX MODES
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作者 刘济科 徐伟华 蔡承武 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第3期361-367,共7页
A universal matrix perturbation technique for complex modes is presented. This technique is applicable to all the three cases of complex eigenvalues: distinct, repeated and closely spaced eigenvalues. The lower order ... A universal matrix perturbation technique for complex modes is presented. This technique is applicable to all the three cases of complex eigenvalues: distinct, repeated and closely spaced eigenvalues. The lower order perturbation formulas are obtained hy performing two complex eigensubspace condensations, and the higher order perturbation formulas are derived hy a successive approximation process. Three illustrative examples are given to verify the proposed method and satisfactory results are observed. 展开更多
关键词 perturbation method complex modes repeated eigenvalues closely spaced eigenvalues
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Design and Implementation of Space Dust Database 被引量:1
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作者 左维 李春来 +2 位作者 徐琳 刘剑 刘建军 《Chinese Journal Of Geochemistry》 EI CAS 2004年第2期135-140,共6页
Space debris is very dangerous to the security of on-the-orbit spacecrafts, and it is increasing in number at high speed with the expansion of human space exploration. Space debris has become a serious space pollutant... Space debris is very dangerous to the security of on-the-orbit spacecrafts, and it is increasing in number at high speed with the expansion of human space exploration. Space debris has become a serious space pollutant noticed by many astronomers. The increase of space dust sources and the development of research on space dust urgently need space dust data sharing and exchanging. It is necessary for us to establish the Space Dust Database to realize the sharing and canonical management of the data. The Space Dust Database (SDD) management system, based on the 3-layer B/S computer mode, was designed and implemented in this paper. The system’s features include significantly improved runtime efficiency, good scalability and maintainability. The Space Dust Database can provide some scientific bases for the study of the chemical constituents, mineral composition, origin and sources of space dust, but also provide excellent data services and decision-making support for the protection of space and model construction of space dust. 展开更多
关键词 灰尘 数据库 空间碎片 轨道飞行 太空船 太空探测
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武汉都市圈生物医药产业链空间格局及空间组织模式 被引量:3
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作者 单卓然 谭玉莲 +1 位作者 袁满 黄亚平 《经济地理》 北大核心 2025年第1期122-133,共12页
文章基于企业间上下游供应往来识别生物医药产业链条,运用核密度分析法、区位熵法、OD分析法等,揭示了武汉都市圈生物医药产业链的空间格局,探究了其空间组织模式。研究发现:①基于场所空间的都市圈生物医药产业链各环节企业分布呈现核... 文章基于企业间上下游供应往来识别生物医药产业链条,运用核密度分析法、区位熵法、OD分析法等,揭示了武汉都市圈生物医药产业链的空间格局,探究了其空间组织模式。研究发现:①基于场所空间的都市圈生物医药产业链各环节企业分布呈现核心集聚、节点集聚、轴带集聚等多样化特点。②基于功能网络的都市圈生物医药产业链各环节内企业关联呈现局地近域关联、层级放射关联、长距离关联等复杂格局。生物医药产业链多环节企业间的空间关联格局有一定规律,表现为前端到中游环节的核心—近域短距离外移、上游到中游环节的外围—近域汇聚式回流、中游到下游环节的近域—全域内外双向输出。③武汉都市圈生物医药产业链遵循圈层布局的基本模式,包括功能协同圈层配合、增值能力圈层递减、交通串联圈层贯通等具体表征。 展开更多
关键词 都市圈 生物医药产业 产业链 空间格局 空间组织模式 武汉市
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