There is a growing interest in the frequency modulated continuous wave (FM-CW) SAR for its small cubage, light weight, cost-effective and high resolution. In this paper, the author deduced the imaging process in detai...
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ISBN:
(纸本)9780780395824
There is a growing interest in the frequency modulated continuous wave (FM-CW) SAR for its small cubage, light weight, cost-effective and high resolution. In this paper, the author deduced the imaging process in detail, discussed the production and the removing of Residual video phase (RVP) as well as the Slope factor, then the improved imaging algorithm is presented by combination de-sloping, range migration correction with pulse compression. The derivation and the simulation proved the algorithm is feasible and correct.
This paper first puts forward a case based system framework based on data mining techniques. Then the paper examines the possibility of using neural networks as a method of retrieval in such a case based system. In ...
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This paper first puts forward a case based system framework based on data mining techniques. Then the paper examines the possibility of using neural networks as a method of retrieval in such a case based system. In this system we propose data mining algorithms to discover case knowledge and other algorithms.
In this paper,we introduce the Auto-Annotation LDA models(aa LDA),a statistical model of non-labeled *** model generates the annotation of LDA *** derive the annotation of LDA using a k-means methods combined with a p...
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In this paper,we introduce the Auto-Annotation LDA models(aa LDA),a statistical model of non-labeled *** model generates the annotation of LDA *** derive the annotation of LDA using a k-means methods combined with a pre-processing of the *** this paper,we use aa LDA models to categorize "zhongwenshilei" corpus,which is a famous Chinese *** we make a compare with the traditional LDA methods.
In the field of electromagnetic radiation source location, using UAVs to locate the radiation source target has become a new location method. At present, the UAV swarm cooperative optimization method for high-precisio...
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This paper describes a method for reducing the information contained in an image sequence, while retaining the information necessary for the interpretation of the sequence by a human observer. The method consists of f...
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This paper describes a method for reducing the information contained in an image sequence, while retaining the information necessary for the interpretation of the sequence by a human observer. The method consists of first locating the redundant information, reducing the degree of redundancy, and coding the result. The sequence is treated as a single 3-D data volume, the voxels of which are grouped into several regions, obtained by a 3-D split and merge algorithm. To find these regions, we first obtain an initial region space by splitting the image sequence until the gray-level variation over each region can be approximated by a 3-D polynomial, to a specified accuracy. This results in a set of parallelepipedic regions of various sizes. To represent the gray-level variation over these regions, the coefficients of the approximating polynomial are used as features. The most similar regions are then merged, using a region adjacency graph. The information is coded by representing the borders of the regions using a pyramidal structure in the x, y, t space. The coefficients of the approximating polynomials are coded in a straightforward manner. For 256 x 256 pixel, 25 frames/s image sequences, compressions allowing transmission rates near 64 kbit/s are obtained.
Network traffic encryption brings security to network communication, however it also brings challenges to network monitoring. As more and more major websites use encryption protocol to protect imformation of visitors,...
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ISBN:
(纸本)9781510830981
Network traffic encryption brings security to network communication, however it also brings challenges to network monitoring. As more and more major websites use encryption protocol to protect imformation of visitors, it is a burning issue to identify client when session is encrypted. In this paper, we present browser identification of HTTPS client based on packet length. The sequence of request packet length is different among browsers and our experiment shows that it is possible to recognize what kind of browser the traffic comes from according to length sequence. We theoretically analyze the possibility of using the request packet length to identify browsers and show the method of using length sequence to establish dictionary. The dictionaries are used to distinguish unknown traffic flow. Our experiment results show that we can get accurate results of browser identification in HTTPS communication through packet length analysis.
Troposcatter propagation is one of major way that ultrashort wave and microwave propagate over horizon. It often forms irregular or stable air layer above sea, so wave propagate by means of incoherent reflecting of th...
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ISBN:
(纸本)9781467309653
Troposcatter propagation is one of major way that ultrashort wave and microwave propagate over horizon. It often forms irregular or stable air layer above sea, so wave propagate by means of incoherent reflecting of the irregular layer or coherent reflecting of the stable layer. The accuracy direction finding of over-water troposcatter propagation signals make sense of situation awareness of targets beyond the horizon. The troposcatter propagation model is built up. The effect of troposcatter propagation mechanism acts on direction finding error is analyzed. This paper has guiding value for amendment of direction finding error.
A new full-aperture imaging algorithm for Spaceborne/ Airborne hybrid sliding spotlight bistatic SAR is proposed in this paper. The SAR configuration under discussion has great advantage over traditional ones, yet suf...
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ISBN:
(纸本)9781849196031
A new full-aperture imaging algorithm for Spaceborne/ Airborne hybrid sliding spotlight bistatic SAR is proposed in this paper. The SAR configuration under discussion has great advantage over traditional ones, yet suffers from the double square-root term in the bistatic slant range equation and severe spatial variance. The proposed method firstly eliminates azimuth spectrum folding by the SPECAN operation, and then corrects the RCM by Chirp Scaling Algorithm. Without interpolation and sub-aperture operations, the algorithm is high in the computational efficiency and simple in the flow. Simulation results confirm the validity of the proposed algorithm.
Random numbers and sequences are widely used in various areas, especially the cryptography for information security. Statistical randomness test is used to evaluate the deviation from randomness. There are lots of sta...
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ISBN:
(纸本)9781467391672
Random numbers and sequences are widely used in various areas, especially the cryptography for information security. Statistical randomness test is used to evaluate the deviation from randomness. There are lots of statistical randomness tests. However, most of the randomness tests focused on the number of occurrences of pre-specified pattern, and lost the information of the distribution of occurrence position. Hence, in this paper, I proposed a new test focusing on the distribution of occurrence position of pre-specified pattern, and proved it by mathematical method. The experimental results show that there has a consistency between the new test and NIST test suite, and in the sense of the distribution of occurrence position of the pre-specified pattern, the new test has advantage over the NIST test suite.
This paper proposed a novel calibration algorithm for sensor position errors of moving sensors by using calibration emitters. The algorithm presented is based on time difference of arrival(TDOA) measurements received ...
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ISBN:
(纸本)9781510845541
This paper proposed a novel calibration algorithm for sensor position errors of moving sensors by using calibration emitters. The algorithm presented is based on time difference of arrival(TDOA) measurements received by sensor network with sensor position error. Firstly, the linear relation between sensor position errors and TDOA measurements is derived by Taylor's series expansion. Then, a linear minimum mean square error(LMMSE) estimator of sensor position errors is derived based on the linear model. At last, on the assumption that sensor position errors of moving sensors are steady in a short time, a sequential LMMSE algorithm for sensor position errors estimation is proposed. Simulation results demonstrate the good performance of the proposed algorithm.
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