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Method for integer ambiguity resolution in GPS network RTK 被引量:5
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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
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A sparse moving array imaging approach for FMCW radar with dualaperture adaptive azimuth ambiguity suppression and adaptive QR decomposition
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作者 Yanwen Han Xiaopeng Yan +3 位作者 Jiawei Wang Sheng Zheng Hongrui Yu Jian Dai 《Defence Technology(防务技术)》 2025年第8期254-271,共18页
Range-azimuth imaging of ground targets via frequency-modulated continuous wave(FMCW)radar is crucial for effective target detection.However,when the pitch of the moving array constructed during motion exceeds the phy... Range-azimuth imaging of ground targets via frequency-modulated continuous wave(FMCW)radar is crucial for effective target detection.However,when the pitch of the moving array constructed during motion exceeds the physical array aperture,azimuth ambiguity occurs,making range-azimuth imaging on a moving platform challenging.To address this issue,we theoretically analyze azimuth ambiguity generation in sparse motion arrays and propose a dual-aperture adaptive processing(DAAP)method for suppressing azimuth ambiguity.This method combines spatial multiple-input multiple-output(MIMO)arrays with sparse motion arrays to achieve high-resolution range-azimuth imaging.In addition,an adaptive QR decomposition denoising method for sparse array signals based on iterative low-rank matrix approximation(LRMA)and regularized QR is proposed to preprocess sparse motion array signals.Simulations and experiments show that on a two-transmitter-four-receiver array,the signal-to-noise ratio(SNR)of the sparse motion array signal after noise suppression via adaptive QR decomposition can exceed 0 dB,and the azimuth ambiguity signal ratio(AASR)can be reduced to below-20 dB. 展开更多
关键词 Frequency modulated continuous wave (FMCW) Sparse motion array Range-azimuth imaging Azimuth ambiguity suppression DAAP Adaptive QR decomposition
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The“two sessions”:institutional investors selloff to avoid ambiguity
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作者 Jiarui Wang Haijun Yang Shancun Liu 《Financial Innovation》 2025年第1期2378-2402,共25页
We construct a model to examine the time-varying ambiguity of investors.When ambiguity occurs concerning recent news,long(short)position investors who are averse to ambiguity reduce(increase)their holdings,resulting i... We construct a model to examine the time-varying ambiguity of investors.When ambiguity occurs concerning recent news,long(short)position investors who are averse to ambiguity reduce(increase)their holdings,resulting in price drops(rises).We empirically analyze how the“two sessions,”a significant event with high policy ambiguity in China,affect the financial market.Our findings suggest that institutional investors mainly sell their holdings between 15 and 5 days before the meetings.Furthermore,the delay in the“two sessions”in 2020 suggests that these selloffs are driven by ambiguity aversion rather than new information. 展开更多
关键词 Two sessions Selloff ambiguity aversion Institutional investors
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Fake News Detection Based on Cross-Modal Ambiguity Computation and Multi-Scale Feature Fusion
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作者 Jianxiang Cao Jinyang Wu +5 位作者 Wenqian Shang Chunhua Wang Kang Song Tong Yi Jiajun Cai Haibin Zhu 《Computers, Materials & Continua》 2025年第5期2659-2675,共17页
With the rapid growth of socialmedia,the spread of fake news has become a growing problem,misleading the public and causing significant harm.As social media content is often composed of both images and text,the use of... With the rapid growth of socialmedia,the spread of fake news has become a growing problem,misleading the public and causing significant harm.As social media content is often composed of both images and text,the use of multimodal approaches for fake news detection has gained significant attention.To solve the problems existing in previous multi-modal fake news detection algorithms,such as insufficient feature extraction and insufficient use of semantic relations between modes,this paper proposes the MFFFND-Co(Multimodal Feature Fusion Fake News Detection with Co-Attention Block)model.First,the model deeply explores the textual content,image content,and frequency domain features.Then,it employs a Co-Attention mechanism for cross-modal fusion.Additionally,a semantic consistency detectionmodule is designed to quantify semantic deviations,thereby enhancing the performance of fake news detection.Experimentally verified on two commonly used datasets,Twitter and Weibo,the model achieved F1 scores of 90.0% and 94.0%,respectively,significantly outperforming the pre-modified MFFFND(Multimodal Feature Fusion Fake News Detection with Attention Block)model and surpassing other baseline models.This improves the accuracy of detecting fake information in artificial intelligence detection and engineering software detection. 展开更多
关键词 Fake news detection MULTIMODAL cross-modal ambiguity computation multi-scale feature fusion
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基于Radon-Ambiguity变换的多分量LFM信号检测与参数估计 被引量:12
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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
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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
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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
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REGULARIZATION APPROACH FOR FAST INTEGER AMBIGUITY RESOLUTION OF MEDIUM-LONG BASELINE GPS NETWORK RTK 被引量:4
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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
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ALGORITHM FOR AMBIGUITY RESOLUTION IN RANGE AND VELOCITY 被引量:1
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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
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Ambiguity in our daily language usage in both English and Chinese 被引量:1
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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
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在单脉冲内利用Hough-Ambiguity变换估计目标加速度研究
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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
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Charlotte Bronte's writing career: The consistent ambiguity of gender
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作者 杨红霞 《Sino-US English Teaching》 2009年第12期60-63,共4页
Although many Chinese scholars have concentrated on Jane Eyre, yet few of them have made research on the other works of Charlotte Bronte. This paper will analyze Jane Eyre, Shirley and Villette in terms of ambiguity o... Although many Chinese scholars have concentrated on Jane Eyre, yet few of them have made research on the other works of Charlotte Bronte. This paper will analyze Jane Eyre, Shirley and Villette in terms of ambiguity of gender, in order to disclose the writing career of Charlotte and the influence that she has placed on the latter women writers. 展开更多
关键词 CHARLOTTE Jane Eyre Shirley VILLETTE ambiguity of gender
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Correlation between Chinese learners' tolerance of ambiguity and their English achievement
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作者 李素真 《Sino-US English Teaching》 2008年第3期35-38,共4页
Tolerance of ambiguity, an important emotional factor, imposes vital influence on second language acquisition. In this study, questionnaires are adopted to investigate the correlation between non-English major's tole... Tolerance of ambiguity, an important emotional factor, imposes vital influence on second language acquisition. In this study, questionnaires are adopted to investigate the correlation between non-English major's tolerance of ambiguity and their English achievement. The result shows that students with different degrees of tolerance of ambiguity can be significantly different in their language performance. Based on the analysis, this article proposes some effective measures to improve the degree of tolerance of ambiguity in English teaching. 展开更多
关键词 tolerance of ambiguity English achievement CORRELATION
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English and Chinese language ambiguity
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作者 程海 《魅力中国》 2009年第13期44-45,共2页
This article from the Voice of Ambiguity, Lexical Ambiguity and Ambiguity in the three aspects of the grammatical structure of English and Chinese languages are compared ambiguity And analysis. Ambiguity in English an... This article from the Voice of Ambiguity, Lexical Ambiguity and Ambiguity in the three aspects of the grammatical structure of English and Chinese languages are compared ambiguity And analysis. Ambiguity in English and Chinese language through the comparison, resulted in two languages to explore the reasons for ambiguity; analysis of the characteristics of English language ambiguities; Research Should not be some ambiguity on how to avoid the emergence of the phenomenon. 展开更多
关键词 speech ambiguity Lexical ambiguity ambiguous grammatical structure
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An Unambiguity and Anti-Range Eclipse Method for PD Radar Using Biphase Coded Signals
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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
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A Systemic-Functional Approach to English Ambiguity
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作者 张静 《海外英语》 2014年第6X期254-255,共2页
This thesis chooses the theory of rank scale and the theory of meta-function in the framework of Systemic-Functional Grammar(SFG)to study ambiguity.It firstly analyzes ambiguities occurring at the rank of morpheme,wor... This thesis chooses the theory of rank scale and the theory of meta-function in the framework of Systemic-Functional Grammar(SFG)to study ambiguity.It firstly analyzes ambiguities occurring at the rank of morpheme,word or phrase.Then it studies ambiguities at the rank of clause,from ideational ambiguity to textual ambiguity.This study shows that SFG can give a systematic and comprehensive interpretation of English ambiguity. 展开更多
关键词 English ambiguity SFG RANK scale meta-function
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Review of Tolerance of Ambiguity
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作者 王爽爽 《海外英语》 2015年第18期224-225,230,共3页
In this paper,definitions of tolerance of ambiguity both at home and abroad are reviewed first.Then studies of tolerance of ambiguity and foreign language teaching both home and abroad are introduced.At last,the paper... In this paper,definitions of tolerance of ambiguity both at home and abroad are reviewed first.Then studies of tolerance of ambiguity and foreign language teaching both home and abroad are introduced.At last,the paper proposed that it is of great significance and practicality for us to make further studies on tolerance of ambiguity. 展开更多
关键词 TOLERANCE of ambiguity FOREIGN LANGUAGE TEACHING
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A Brief Analysis of Ambiguity of Words' Meaning in Translation
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作者 杨柳 《海外英语》 2016年第7期140-141,共2页
As you can see from the title,we try to provide a brief analysis of ambiguity of words' meaning in translation practice,namely,what is ambiguity of a meaning of a word and how it is caused,and how it affects trans... As you can see from the title,we try to provide a brief analysis of ambiguity of words' meaning in translation practice,namely,what is ambiguity of a meaning of a word and how it is caused,and how it affects translation.What effective methods are available to help us achieve a successful translation? Although a perfect solution for the problems presented by the ambiguity of words' meaning is difficult to find,we try to do what it can to contribute to the solution and draw people's attention to those problems. 展开更多
关键词 ambiguity MEANING of WORDS TRANSLATION
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Analysis of Ambiguity in Newspaper Headlines from a Cognitive Perspective
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作者 刘启迪 《海外英语》 2011年第15期310-312,共3页
Ambiguity in newspaper headlines have been studied by many people, which mostly focuses upon the traditional linguistics perspective: lexical, grammatical and syntactical. In this paper, the author intends to study th... Ambiguity in newspaper headlines have been studied by many people, which mostly focuses upon the traditional linguistics perspective: lexical, grammatical and syntactical. In this paper, the author intends to study the ambiguity in newspaper headlines from the cognitive perspective in order to find how people perceive the ambiguous headlines. To support the analysis, many examples of ambiguous headlines are collected to investigate into way people perceive them. Finally, the author concluded that in the cognitive perspective, people are prone to accept one of the two or more interpretations about the ambiguous headlines according to the following factors: their back ground knowledge, the common sense, the social-cultural environment as well as their personal altitudes, which are drawn upon from the image schema theory. 展开更多
关键词 ambiguity NEWSPAPER HEADLINE COGNITIVE PERSPECTIVE
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Feature study for improving Chinese overlapping ambiguity resolution based on SVM 被引量:1
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作者 熊英 朱杰 《Journal of Southeast University(English Edition)》 EI CAS 2007年第2期179-184,共6页
In order to improve Chinese overlapping ambiguity resolution based on a support vector machine, statistical features are studied for representing the feature vectors. First, four statistical parameters-mutual informat... In order to improve Chinese overlapping ambiguity resolution based on a support vector machine, statistical features are studied for representing the feature vectors. First, four statistical parameters-mutual information, accessor variety, two-character word frequency and single-character word frequency are used to describe the feature vectors respectively. Then other parameters are tried to add as complementary features to the parameters which obtain the best results for further improving the classification performance. Experimental results show that features represented by mutual information, single-character word frequency and accessor variety can obtain an optimum result of 94. 39%. Compared with a commonly used word probability model, the accuracy has been improved by 6. 62%. Such comparative results confirm that the classification performance can be improved by feature selection and representation. 展开更多
关键词 support vector machine Chinese overlapping ambiguity Chinese word segmentation word probability model
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