期刊文献+
共找到5,775篇文章
< 1 2 250 >
每页显示 20 50 100
Trial application of the envelope method to the potential ambiguity problem
1
作者 Li-Yuan Hu Yu-Shou Song 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期73-80,共8页
The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and f... The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering components.By contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,respectively.Hence,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity problem.In this study,we conducted a trial application of the envelope method to the potential ambiguity problem.The envelope method was improved by including uncertainties in the experimental data.The colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the analyses.For each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is refractive.The calculated angular distributions were decomposed into nearside and farside scattering components.Using the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside components.The capability of the envelope method to analyze the potential ambiguities was also discussed. 展开更多
关键词 Elastic scattering Optical potential ambiguities Envelope method Nearside/farside decomposition
下载PDF
Low-Complexity Integrated Super-Resolution Sensing and Communication with Signal Decimation and Ambiguity Removal
2
作者 DAI Qianglong ZHOU Zhiwen +3 位作者 XIAO Zhiqiang ZENG Yong YANG Fei CHEN Yan 《ZTE Communications》 2024年第3期48-55,共8页
Integrated sensing and communication(ISAC)is one of the main usage scenarios for 6G wireless networks.To most efficiently utilize the limited wireless resources,integrated super-resolution sensing and communication(IS... Integrated sensing and communication(ISAC)is one of the main usage scenarios for 6G wireless networks.To most efficiently utilize the limited wireless resources,integrated super-resolution sensing and communication(ISSAC)has been recently proposed to significantly improve sensing performance with super-resolution algorithms for ISAC systems,such as the Multiple Signal Classification(MUSIC)algorithm.However,traditional super-resolution sensing algorithms suffer from prohibitive computational complexity of orthogonal-frequency division multiplexing(OFDM)systems due to the large dimensions of the signals in the subcarrier and symbol domains.To address such issues,we propose a novel two-stage approach to reduce the computational complexity for super-resolution range estimation significantly.The key idea of the proposed scheme is to first uniformly decimate signals in the subcarrier domain so that the computational complexity is significantly reduced without missing any target in the range domain.However,the decimation operation may result in range ambiguity due to pseudo peaks,which is addressed by the second stage where the total collocated subcarrier data are used to verify the detected peaks.Compared with traditional MUSIC algorithms,the proposed scheme reduces computational complexity by two orders of magnitude,while maintaining the range resolution and unambiguity.Simulation results verify the effectiveness of the proposed scheme. 展开更多
关键词 ISSAC sparse decimation range ambiguity two-stage approach
下载PDF
Optimal Insurance with Background Risk under the Ambiguity and Belief Heterogeneity Structure
3
作者 Xiaohan Wang 《Journal of Applied Mathematics and Physics》 2024年第6期2160-2171,共12页
In this paper, we discuss the optimal insurance in the presence of background risk while the insured is ambiguity averse and there exists belief heterogeneity between the insured and the insurer. We give the optimal i... In this paper, we discuss the optimal insurance in the presence of background risk while the insured is ambiguity averse and there exists belief heterogeneity between the insured and the insurer. We give the optimal insurance contract when maxing the insured’s expected utility of his/her remaining wealth under the smooth ambiguity model and the heterogeneous belief form satisfying the MHR condition. We calculate the insurance premium by using generalized Wang’s premium and also introduce a series of stochastic orders proposed by [1] to describe the relationships among the insurable risk, background risk and ambiguity parameter. We obtain the deductible insurance is the optimal insurance while they meet specific dependence structures. 展开更多
关键词 Optimal Insurance Monotone Hazard Ratio Order Smooth ambiguity Model Background Risk Belief Heterogeneity Structure
下载PDF
Translation Strategies of Ambiguity in English Language and Literature
4
作者 Ying Gao 《Journal of Contemporary Educational Research》 2024年第2期138-143,共6页
The translation of English language and literary works has always been crucial for cross-cultural communication.However,a key challenge in translating such works is the accurate communication of ambiguity,which refers... The translation of English language and literary works has always been crucial for cross-cultural communication.However,a key challenge in translating such works is the accurate communication of ambiguity,which refers to expressions deliberately used in English texts with unclear meanings.These expressions are often poetic and carry deep symbols and implications,adding a unique charm to literary works.This article explores the manifestations of ambiguity in English language and literature and the translation strategies that can be employed to optimize the translation of ambiguity in the English language and literature. 展开更多
关键词 ENGLISH Language and literature ambiguity TRANSLATION
下载PDF
An Unambiguity and Anti-Range Eclipse Method for PD Radar Using Biphase Coded Signals
5
作者 Jihong Yan Weihan Ni +1 位作者 Jianshu Zhai Haiyang Dong 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期1337-1351,共15页
Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)t... Target detection is an important research content in the radar field.At present,efforts are being made to optimize the precision of detection information.In this paper,we use the high pulse repetition frequency(HPRF)transmission method and orthogonal biphase coded signals in each pulse to avoid velocity ambiguity and range ambiguity of radar detection.In addition,We also apply Walsh matrix and genetic algorithm(GA)to generate satisfying orthogonal biphase coded signals with low auto-correlation sidelobe peak and cross-correlation peak,which make the results more accurate.In a radar receiver,data rearrangement of echo signals is performed,and then pulse compression and moving target detection(MTD)are utilized to get the final velocity and range information of a target without velocity ambiguity and range ambiguity.Besides,a small transmitting pulse time width is adopted to reduce the working blind area,and two different high pulse repetition frequencies(HPRFs)are adopted to solve the problem of range eclipse.Simulation results finally prove the effectiveness and feasibility of the proposed method. 展开更多
关键词 Biphase coded velocity ambiguity range ambiguity genetic algorithm range eclipse
下载PDF
Effects of ambiguity on innovation strategies
6
作者 Hwa‑Sung Kim 《Financial Innovation》 2023年第1期1813-1839,共27页
Technological innovations significantly influence individual firms and other innova-tions,such as financial innovations.The future of a firm depends on its innovation investment strategy.According to the literature,in... Technological innovations significantly influence individual firms and other innova-tions,such as financial innovations.The future of a firm depends on its innovation investment strategy.According to the literature,innovation investments are affected by ambiguity.This study examines how ambiguity affects the innovation strategies of managers.We show that the innovation strategies of ambiguity-averse managers differ from those of ambiguity-neutral managers.Unlike ambiguity-neutral managers,ambiguity-averse managers consider a broader variety of innovation strategies for a wider range of future innovation arrival times.Regarding the profitability of a future innovation,ambiguity-averse managers delay the investment decision until the profit-ability of the innovation is less ambiguous.Moreover,we examine innovation strategies under various conditions,including the risk of innovation outdatedness,management disputes,and the varying volatility of innovations. 展开更多
关键词 Technological innovation ambiguity Innovation strategy
下载PDF
Ambiguity function analysis and side peaks suppression of Link16 signal based passive radar
7
作者 BAI Luyang WANG Jun CHEN Xiaoling 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2023年第6期1526-1536,共11页
Link16 data link is the communication standard of the joint tactical information distribution system(JTIDS)used by the U.S.military and North Atlantic Treaty Organization,which is applied as the opportunistic illumina... Link16 data link is the communication standard of the joint tactical information distribution system(JTIDS)used by the U.S.military and North Atlantic Treaty Organization,which is applied as the opportunistic illuminator for passive radar in this paper.The time-domain expression of the Link16 signal is established,and its ambiguity function expression is derived.The timedelay dimension and Doppler dimension side peaks of which lead to the appearance of the false target during target detection.To solve the problem,the time-delay dimension and Doppler dimension side peaks suppression methods are proposed.For the problem that the conventional mismatched filter(MMF)cannot suppress the time-delay dimension side peaks,a neighborhood MMF(NMMF)is proposed.Experimental results demonstrate the effectiveness of the proposed methods. 展开更多
关键词 passive radar ambiguity function LINK16 mismatched filter(MMF)
下载PDF
基于Radon-Ambiguity变换的多分量LFM信号检测与参数估计 被引量:12
8
作者 刘爱芳 朱晓华 +1 位作者 陆锦辉 刘中 《南京理工大学学报》 EI CAS CSCD 北大核心 2004年第4期409-413,共5页
介绍了Radon -Ambiguity变换 (RAT)的定义和基本性质 ,结合解线调技术提出了一种基于RAT的线性调频 (LFM )信号检测与参数估计方法 ,该方法能用较少的计算量完成对LFM信号的检测与参数估计。为解决多分量条件下LFM信号分量之间交叉项的... 介绍了Radon -Ambiguity变换 (RAT)的定义和基本性质 ,结合解线调技术提出了一种基于RAT的线性调频 (LFM )信号检测与参数估计方法 ,该方法能用较少的计算量完成对LFM信号的检测与参数估计。为解决多分量条件下LFM信号分量之间交叉项的影响 ,基于逐次消去思想 ,提出了一种基于RAT的多分量LFM信号检测与参数估计算法 ,它可以有效地解决强度相差较大的多分量LFM信号的检测和参数估计问题。仿真实验结果验证了该算法的有效性。 展开更多
关键词 Radon—ambiguity变换 线性调频信号 参数估计
下载PDF
分级计算迭代在Radon-Ambiguity变换和分数阶Fourier变换对chirp信号检测及参数估计的应用 被引量:18
9
作者 郭斌 张红雨 《电子与信息学报》 EI CSCD 北大核心 2007年第12期3024-3026,共3页
该文在分析Radon-Ambiguity变换(RAT)和分数阶Fourier变换对chirp信号的检测和参数估计的基础上,建立了多分量chirp信号检测和参数估计系统模型,提出了分级计算迭代方法,大大减少了计算量,提高了运算速度。
关键词 分数阶FOURIER变换 Radon—ambiguity变换 CHIRP信号
下载PDF
Method for integer ambiguity resolution in GPS network RTK 被引量:5
10
作者 潘树国 王庆 +1 位作者 柯福阳 邓健 《Journal of Southeast University(English Edition)》 EI CAS 2009年第4期491-495,共5页
A method for integer ambiguity resolution in the global positioning system (GPS) multi-reference station network real time kinematic (RTK) is proposed. First, the barycenter of the triangle of reference stations f... A method for integer ambiguity resolution in the global positioning system (GPS) multi-reference station network real time kinematic (RTK) is proposed. First, the barycenter of the triangle of reference stations for ambiguity resolution is taken as a reference point. The satellite which has the largest elevation angle with the reference point is selected as a reference satellite. The parameters for constructing the weight matrix of carrier phase observation and the criteria for checking the correctness of integer ambiguity resolution of a network are obtained. Then, the wide ambiguity is calculated by a linear combination method of dualband observation. And the LI ambiguity is obtained by a nonionosphere combination method. The Kalman filter is introduced to refine the floating-point solution of ambiguity and estimate the real-time tropospheric delay. Finally, the cofactor matrix of ambiguity is de-correlated by Z-transformation to reduce the searching space of the integer ambiguity solution and improve the efficiency of the least-squares ambiguity decorrelation adjustment (LAMBDA) algorithm. The experimental results show that this method can reliably obtain the integer ambiguity solution among multi-reference stations with 40 epochs. 展开更多
关键词 network real time kinematic ambiguity troposphere: reference satellite least-squares ambiguity decorrelation adjustment
下载PDF
REGULARIZATION APPROACH FOR FAST INTEGER AMBIGUITY RESOLUTION OF MEDIUM-LONG BASELINE GPS NETWORK RTK 被引量:4
11
作者 罗孝文 欧吉坤 袁运斌 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第3期235-242,共8页
An improved method based on the Tikhonov regularization principle and the precisely known reference station coordinate is proposed to design the regularized matrix. The ill-conditioning of the normal matrix can be imp... An improved method based on the Tikhonov regularization principle and the precisely known reference station coordinate is proposed to design the regularized matrix. The ill-conditioning of the normal matrix can be improved by the regularized matrix. The relative floating ambiguity can be computed only by using the data of several epochs. Combined with the LAMBDA method, the new approach can correctly and quickly fix the integer ambiguity and the success rate is 100% in experiments. Through using measured data sets from four mediumlong baselines, the new method can obtain exact ambiguities only by the Ll-frequency data of three epochs. Compared with the existing methods, the improved method can solve the ambiguities of the medium-long baseline GPS network RTK only using L1-frequency GPS data. 展开更多
关键词 GPS network RTK integer ambiguity fast resolution
下载PDF
ALGORITHM FOR AMBIGUITY RESOLUTION IN RANGE AND VELOCITY 被引量:1
12
作者 张弓 朱兆达 吕波 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2001年第2期219-223,共5页
For enhancing performances and increasing functions of PD radar, High PRF, medium PRF and low PRF are commonly applied into system ambiguity appeared in range and velocity in some PRF. Based on clustering, a slidin... For enhancing performances and increasing functions of PD radar, High PRF, medium PRF and low PRF are commonly applied into system ambiguity appeared in range and velocity in some PRF. Based on clustering, a sliding window correlator algorithm for resolving the radar object ambiguity in range and velocity is described. Slide window algorithm is a searching algorithm. The probability of ambiguity resolution for targets and the computational efficiency are discussed. The relations between the probability of ambiguity resolution of this algorithm and PRF, the range of interest, and the width of sliding window are analyzed. Simulational results are also given. 展开更多
关键词 PD radar ambiguity resolution sliding window CLUSTERING
下载PDF
基于Radon-Ambiguity变换和分数阶傅里叶变换的chirp信号检测及多参数估计 被引量:43
13
作者 赵兴浩 陶然 +1 位作者 周思永 王越 《北京理工大学学报》 EI CAS CSCD 北大核心 2003年第3期371-374,377,共5页
研究噪声环境中chirp信号的检测以及多参数估计问题.分析和比较了Radon-Wigner变换(RWT)法、Radon-Ambiguity变换(RAT)法和分数阶傅里叶变换(FRFT)扫描法的优缺点.提出了一种基于RAT和FRFT的新算法,并提出了幅度估计的一种适合于计算的... 研究噪声环境中chirp信号的检测以及多参数估计问题.分析和比较了Radon-Wigner变换(RWT)法、Radon-Ambiguity变换(RAT)法和分数阶傅里叶变换(FRFT)扫描法的优缺点.提出了一种基于RAT和FRFT的新算法,并提出了幅度估计的一种适合于计算的表达式.最后通过计算机仿真验证了该方法的有效性.这种方法与RWT法和FRFT扫描法相比,将chirp信号的检测问题变为一维搜索问题,简化了计算,与单纯的RAT法相比,有效地解决了chirp信号的初始频率和幅度的估计问题.因此,适合于对chirp信号多参数联合估计. 展开更多
关键词 分数阶傅里叶变换 RADON-ambiguity变换 CHIRP信号 多参数估计
下载PDF
基于Radon-ambiguity变换的ISAR成像算法 被引量:4
14
作者 刘爱芳 刘中 陆锦辉 《现代雷达》 CSCD 北大核心 2003年第6期12-14,34,共4页
非匀速旋转目标和机动目标成像是逆合成孔径雷达 (ISAR)技术的一个重点和难点 ,经典的距离 -多普勒(RD)算法对其成像效果不佳。本文首先分析了ISAR成像回波信号模型 ,然后在对目标多普勒变化曲线作一阶近似的条件下提出了基于Radon Ambi... 非匀速旋转目标和机动目标成像是逆合成孔径雷达 (ISAR)技术的一个重点和难点 ,经典的距离 -多普勒(RD)算法对其成像效果不佳。本文首先分析了ISAR成像回波信号模型 ,然后在对目标多普勒变化曲线作一阶近似的条件下提出了基于Radon Ambiguity变换 (RAT)的ISAR成像算法。最后进行仿真实验 ,仿真实验结果表明了该方法的有效性。 展开更多
关键词 RADON-ambiguity变换 逆合成孔径雷达 ISAR RAT 成像算法 线性调频信号
下载PDF
基于局部Radon-Ambiguity变换的ARM检测技术 被引量:2
15
作者 方前学 王永良 王首勇 《系统工程与电子技术》 EI CSCD 北大核心 2008年第11期2151-2154,共4页
针对反辐射导弹(anti-radiation missile,ARM)雷达回波信号的调频率特性,提出了基于局部Radon-Ambiguity变换(RAT)的ARM检测方法。该方法对导弹的初速度不敏感,也不需要对导弹加速度进行多通道相位补偿预处理。通过将RAT局部化,进一步... 针对反辐射导弹(anti-radiation missile,ARM)雷达回波信号的调频率特性,提出了基于局部Radon-Ambiguity变换(RAT)的ARM检测方法。该方法对导弹的初速度不敏感,也不需要对导弹加速度进行多通道相位补偿预处理。通过将RAT局部化,进一步缩小了检测区域和运算量,提高了检测效率。检测性能分析和仿真实验表明,该方法能够在较低信噪比环境下有效地检测ARM目标信号。 展开更多
关键词 目标检测 局部Radon-ambiguity变换 线性调频信号 反辐射导弹
下载PDF
Ambiguity in our daily language usage in both English and Chinese 被引量:1
16
作者 雷春林 《Sino-US English Teaching》 2008年第1期9-14,44,共7页
Ambiguity is a unique linguistic feature and is caused by many factors. This paper first introduces the definitions of ambiguity and then mainly illustrates ambiguity in our daily language usage in both English and Ch... Ambiguity is a unique linguistic feature and is caused by many factors. This paper first introduces the definitions of ambiguity and then mainly illustrates ambiguity in our daily language usage in both English and Chinese from phonetic level and syntactic level. People can learn the relationships among those levels and grasp the rule of learning language. Thus, people can realize the complexity and importance of using language and know that it is not easy to express ideas accurately. 展开更多
关键词 ambiguity phonetic level syntactic level daily language usage
下载PDF
在单脉冲内利用Hough-Ambiguity变换估计目标加速度研究
17
作者 贾舒宜 王国宏 杜文超 《海军航空工程学院学报》 2008年第1期33-36,共4页
根据雷达发射恒定载频信号时匀加速目标的回波为线性调频(LFM)信号的特点,研究了在单脉冲内基于Hough—Ambiguity变换(HAT)估计目标径向加速度的问题。首先,采用Hough—Ambiguity变换得到信号的调频斜率;进而,根据调频斜率估计... 根据雷达发射恒定载频信号时匀加速目标的回波为线性调频(LFM)信号的特点,研究了在单脉冲内基于Hough—Ambiguity变换(HAT)估计目标径向加速度的问题。首先,采用Hough—Ambiguity变换得到信号的调频斜率;进而,根据调频斜率估计出目标径向加速度;最后,仿真实验结果验证了方法的有效性。 展开更多
关键词 Hough—ambiguity变换 径向加速度 线性调频信号
下载PDF
在单脉冲内基于Radon-Ambiguity变换的加速度估计方法研究 被引量:4
18
作者 贾舒宜 王国宏 杜文超 《宇航学报》 EI CAS CSCD 北大核心 2008年第3期989-994,共6页
根据雷达发射恒定载频信号时匀加速目标回波为线性调频(LFM)信号的特点,研究了在单脉冲内基于Radon-Ambiguity变换(RAT)估计目标径向加速度的问题,首先采用Radon-Ambiguity变换(RAT)得到信号的调频斜率,进而根据调频斜率估计出目标径向... 根据雷达发射恒定载频信号时匀加速目标回波为线性调频(LFM)信号的特点,研究了在单脉冲内基于Radon-Ambiguity变换(RAT)估计目标径向加速度的问题,首先采用Radon-Ambiguity变换(RAT)得到信号的调频斜率,进而根据调频斜率估计出目标径向加速度。分析了加速度分辨率和加速度估计效率,讨论了信号时长和搜索步长对测量加速度精度的影响,最后仿真实验结果验证了方法的有效性。 展开更多
关键词 RADON-ambiguity变换 径向加速度 线性调频信号 RADON-WIGNER变换 WIGNER-HOUGH变换
下载PDF
基于Radon-Ambiguity变换和解调频技术的SAR运动目标检测 被引量:2
19
作者 姜义成 韩逸飞 《现代雷达》 CSCD 北大核心 2005年第5期41-44,共4页
详细探讨了合成孔径雷达中运动目标的检测问题,根据机载合成孔径雷达运动目标回波信号的特点,提出了基于Radon- Ambiguity变换和解调频技术的一种新的机载运动目标检测方法,给出了动目标检测、参数估计的主要步骤,分析了在单目标和多目... 详细探讨了合成孔径雷达中运动目标的检测问题,根据机载合成孔径雷达运动目标回波信号的特点,提出了基于Radon- Ambiguity变换和解调频技术的一种新的机载运动目标检测方法,给出了动目标检测、参数估计的主要步骤,分析了在单目标和多目标情况下的检测性能。该方法与常用的Wigner- Ville分布和Radon变换结合的方法相比计算量明显减少,在多目标情况下能够较好地抑制交叉项,提高检测性能。且使用解调频技术与RAT相配合,解决了单纯RAT无法估计Chirp信号初始频率的问题。仿真试验结果证明了算法的有效性。 展开更多
关键词 合成孔径雷达 运动目标检测 RADON-ambiguity变换 解调频技术
下载PDF
基于Radon-Ambiguity变换的LFM信号时/频差快速联合估计 被引量:1
20
作者 杨林森 张子敬 郭付阳 《电波科学学报》 EI CSCD 北大核心 2016年第6期1074-1080,共7页
提出了一种基于Radon-Ambiguity变换(Radon-Ambiguity Transform,RAT)的线性调频(Linear Frequency Modulated,LFM)信号时/频差快速联合估计的算法.根据LFM信号在多个不同角度上的RAT峰值位置建立一组以信号间时差和频差为未知量的方程... 提出了一种基于Radon-Ambiguity变换(Radon-Ambiguity Transform,RAT)的线性调频(Linear Frequency Modulated,LFM)信号时/频差快速联合估计的算法.根据LFM信号在多个不同角度上的RAT峰值位置建立一组以信号间时差和频差为未知量的方程组,求解方程组即可得到时/频差的估计值.对于存在噪声的信号,RAT误差会导致方程组不能直接求解,为了抑制噪声干扰,采用最小二乘法估计时/频差.本文算法无需计算二维平面上各点的模糊函数值,并且由于离散RAT可以通过快速傅里叶变换快速实现,具有所需运算量低的优点.仿真实验表明,相比于常见的基于模糊函数峰值搜索的时/频差估计算法,本文算法在保证时/频差估计精度的同时能够显著提高运算效率. 展开更多
关键词 RADON-ambiguity变换 最小二乘法 时/频差 线性调频信号
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部