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Multi-dimensional Ambiguity function for subarray-based space-time coding radar

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Journal of Systems Engineering and Electronics 2019年第5期30卷 886-896页

作者： LAN Lan LIAO Guisheng XU Jingwei WANG Hanbing National Laboratory of Radar Signal Processing Xidian University

Space-time coding radar has been recently proposed and investigated.It is a radar framework which can perform transmit beamforming at the receiver.However,the range resolution decreases when the number of the transmit element increases.A subarray-based space-time coding(sub-STC)radar is explored to alleviate the range resolution reduction.For the proposed radar configuration,an identical waveform is transmitted and it introduces a small time offset in different subarrays.The multidimensional Ambiguity function of sub-STC radar is defined by considering resolutions in multiple domains including the range,Doppler,angle and probing direction.Analyses on properties of the multi-dimensional Ambiguity function of the sub-STC radar with regard to the spatial coverage,resolution performance and low sidelobes are also given.Results reveal that the range resolution and low sidelobes performance are improved with the proposed approach.

关键词： space-time coding radar multi-dimensional Ambiguity function range resolution wide spatial coverage subarray sidelobe

Analysis of the Ambiguity of log-constrained seismic impedance inversion

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Petroleum Science 2011年第2期8卷 151-156页

作者： Li Guofa Li Hao Ma Yanyan Xiong Jinliang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum (Beijing) Beijing 102249 China Key Laboratory of Geophysical Prospecting China National Petroleum Corporation Beijing 102249 China Dagang Oil field PetroChina Tianjin 300280 China

Although the Ambiguity of seismic inversion is widely recognized in both theory and practice, so far as a concrete inversion example is concerned, there is not any objective, controllable method or any standard for how to evaluate and determine its Ambiguity and reliability, especially for the high frequency components beyond the effective seismic frequency band. Taking log-constrained impedance inversion as an example, a new appraisal method is proposed on the basis of analyzing a simple geological model. Firstly, the inverted impedance model is transformed to a reflection coefficient series. Secondly, the maximum effective frequency of the real seismic data is chosen as a cutoff point and the reflection coefficient series is decomposed into two components by low-pass and high-pass filters. Thirdly, the geometrical reflection characteristics of the high-frequency components and that of the real seismic data are compared and analyzed. Then, the reliability of the inverted impedance model is appraised according to the similarity of geometrical characteristics between the high-frequency components and the real seismic data. The new method avoids some subjectivity in appraising the inverted result, and helps to enhance the reliability of reservoir prediction by impedance inversion technology.

关键词： Log-constrained impedance reflection coefficients seismic inversion Ambiguity

Adaptive Robust Filtering Algorithm for BDS Medium and Long Baseline Three Carrier Ambiguity Resolution

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Journal of Geodesy and Geoinformation Science 2020年第2期3卷 53-61页

作者： Yangjun GAO Zhiwei LV Pengjin ZHOU Zhengyang JIA Lundong ZHANG Dianwei CONG Institute of Geospatial Information Information Engineering UniversityZhengzhou 450001China

For classical TCAR(three carrier Ambiguity resolution)algorithm is affected by ionospheric delay and measurement noise,it is difficult to reliably fix Ambiguity at medium and long baselines.An improved TCAR algorithm which takes the influence of ionospheric delay into account and has good adaptive robustness is proposed.On the basis of the non-geometric TCAR model,ionospheric delay is obtained by linearly combining extra-wide-lane with fixed Ambiguity,and then wide-lane Ambiguity is solved.Solving narrow-lane Ambiguity by adaptive robust filtering by constructing optimal combination observation,which can effectively improve the fixed success rate of narrow-lane Ambiguity and reduce the adverse effects of gross error.Experimental results show that the improved TCAR algorithm can guarantee a high fixed correct rate of wide-lane Ambiguity,effectively improve fixed success rate of narrow-lane Ambiguity,and has a good ability to resist gross error.

关键词： adaptive robust filter Beidou wide-lane narrow-lane Ambiguity TCAR

Measurement for Phase Difference Rate without Phase Ambiguity

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Journal of Electronic & Information Systems 2019年第1期1卷 3-17页

作者： Yu Tao 51 st Research Institute of CETC Shanghai201802China

Firstly,the direction finding solution at the midpoint of a single base array is given for the purpose of this paper and the several functions relation between phase and frequency is also described.Then,the expression of phase difference rate is described based on the multichannel phase difference measurement.With stripping time difference item correspond to the baseline length from phase difference rate,a function is extracted which signifies the differential characteristics of wavelength integer and phase difference in a unit of length.Simulation calculation found that the variation of differential function of path difference in a unit of length is very regular.The corresponding corrected value can is determine directly by distinguishing the range of differential item of phase difference obtained by actual measurement.Thus,the function expression can be obtained that is equivalence with the quondam differential function of path difference and that is nothing to do with the difference item of wavelength integer.On this basic,several parameters are analyzed by using the method of phase difference measurement without phase Ambiguity.The research results in this paper may provide a powerful technical support for engineering practical design related to the phase measuring.

关键词： Phase difference rate Phase Ambiguity Doppler frequency shift Path difference Passive location

The Trend of Indo-Pacific Strategy and its Impact on the U.S.-Japan Alliance——Creating and evolving of dual Ambiguity, dual assurance and dual check strategies

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Peace 2019年第1期 57-69页

作者： Gao Lan the Center for Japanese Studies Fudan University

In recent years, since the Obama Administration, the policy discussions on the Indo-Pacific region have gradually moved from conceptualization to strategy. The Indo-Pacific strategy is established during the Trump Administration, in which, Japan played a leading role. The Indo-Pacific strategy is advanced jointly by the United States and Japan. In this process, the three characteristics of dual Ambiguity, dual assurance and dual check are taking shape, which has a compound influence on the Japan-U.S. alliance and showed the interaction between tension and synergy. Compared with the Asia-Pacific strategy, building a huge Indo-Pacific strategy requires more costs, and Indo-Pacific countries are paying close attention to its development trend.

关键词： Creating and evolving of dual Ambiguity Japan Alliance Indo-Pacific Strategy

燕卜荪Ambiguity理论在中国的跨语际实践

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燕卜荪ambiguity理论在中国的跨语际实践

作者：周春梅重庆师范大学

学位级别：硕士

威廉·燕卜荪于20世纪30年代末期来中国任教，他的Ambiguity理论对中国诗学界产生了重大影响。燕卜荪Ambiguity理论作为西方语境下产生的文学理论伴随着新批评的引进和燕卜荪来华执教而为中国学者所接受。但是这一理论在中国语境下的传... 详细信息

威廉·燕卜荪于20世纪30年代末期来中国任教，他的Ambiguity理论对中国诗学界产生了重大影响。燕卜荪Ambiguity理论作为西方语境下产生的文学理论伴随着新批评的引进和燕卜荪来华执教而为中国学者所接受。但是这一理论在中国语境下的传播并非一成不变，而是在接触、冲突、交流中发生变异，最终成为中国现当代文论中的一部分。燕卜荪的Ambiguity理论对中国现代文论的构建和丰富具有积极作用。目前国内对燕卜荪的学术研究较少，尚无对燕卜荪Ambiguity理论在中国语境下的传播实践进行系统研究的文章和专著，因此仍有一些值得探讨、分析的问题。本论文遵循理论分析与史料梳理相结合的原则，对燕卜荪Ambiguity理论在中国的跨语际实践展开横向的多角度分析。论文按燕卜荪Ambiguity理论在中国实现跨语际实践的原因、途径、结果的逻辑顺序进行探讨。重点探究该理论跨语际实践的结果，主要从燕卜荪Ambiguity理论本体、批评实践、对中国文论的影响及其对文学创作的影响等方面进行分析，使其呈现出层面差异性和内在关联性。同时，又以燕卜荪Ambiguity理论在时间序列的发展变化为线索，以呈现其丰富性和立体感。研究燕卜荪Ambiguity理论在中国的语际实践是对燕卜荪理论研究的继续，更是对中国现代文论的丰富，同时也是为中国文学理论、批评实践和文学创作提供借鉴。

关键词：燕卜荪 Ambiguity 跨语际实践

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文学术语Ambiguity的翻译探究

中国科技术语 2017年第4期19卷 29-35页

作者：魏亮 <中国科技术语>杂志社北京100717

燕卜荪的Ambiguity这一文学术语在中国曾有过十余种译法,至今仍是"复义""含混""朦胧""歧义"等多种译法并存。根据Ambiguity在英语中本来的含义和在燕卜荪理论中的意涵,"朦胧""含混"等译法涵盖是不全面的,也偏离了概念的本质,"歧义""多义... 详细信息

燕卜荪的Ambiguity这一文学术语在中国曾有过十余种译法,至今仍是"复义""含混""朦胧""歧义"等多种译法并存。根据Ambiguity在英语中本来的含义和在燕卜荪理论中的意涵,"朦胧""含混"等译法涵盖是不全面的,也偏离了概念的本质,"歧义""多义"等译法也各有不妥之处。"复义"改自"复意",两个词的差异在于"义"和"意"的区别。据此,Ambiguity应当译作"复意"。

关键词： Ambiguity 燕卜荪复义复意

Review of Tolerance of Ambiguity

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海外英语 2015年第18期 224-225,230页

作者：王爽爽山东师范大学外国语学院

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.

关键词： tolerance of Ambiguity foreign language teaching

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基督教美术中牛的形象与歧义