This paper describes an approach for ground moving targets detection and relocation in heterogeneous environment which requires three consecutive operations as follows: Firstly, some deleterious factors correction tec...
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This paper describes an approach for ground moving targets detection and relocation in heterogeneous environment which requires three consecutive operations as follows: Firstly, some deleterious factors correction techniques are adopted before clutter rejection. Secondly, different window selection strategies, aiming at different image coregistration error, are given to form the joint data vector for clutter rejection. Finally, the true target steering vector is derived in the presence of image coregistration error and channel mismatch, based on which the radial velocities of moving targets can be determined. Results of measured dataprocessing are included to verify the robustness of this algorithm.
The brain is the most complex organ in the human body, and it is also the most complex organ in the whole biological system, making it the most complex organ on the planet. According to the findings of current studies...
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The present paper describes the development of geophysical navigation (GN) methods for small, affordable underwater robotic vehicles. The proposed GN methods includes a classical, bathymetric-based terrain-aided navig...
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ISBN:
(纸本)9781509015375
The present paper describes the development of geophysical navigation (GN) methods for small, affordable underwater robotic vehicles. The proposed GN methods includes a classical, bathymetric-based terrain-aided navigation (TAN) approach, a magnetic-based geophysical navigation solution (MAGNAV), and an integration of both methods (TAN-MAGNAV). Due to insufficient topographic features in the adopted test site, the classical TAN approach performed poorly in terms of positioning accuracy. To mitigate this, the complementarity of magnetic and topographic terrain information was exploited, initially using only magnetic data to estimate the vehicle position and later by fusing magnetic and altitude data. The results obtained illustrate the high potential of using magnetic data for geophysical navigation of autonomous underwater vehicles. The navigation methods described are validated in simulated trials using real magnetic, topographic, and navigation data acquired with an autonomous marine vehicle in real trials. The equipment employed in the proposed solution consists of standard navigation sensors, a sonar altimeter, and an affordable total field magnetometer.
In order to apply the statistical approach to the classification of multisensor remote sensing data, one of the main problems lies in the estimation of the joint probability density functions (pdfs) f(X\omega (k)) of ...
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ISBN:
(纸本)081943826X
In order to apply the statistical approach to the classification of multisensor remote sensing data, one of the main problems lies in the estimation of the joint probability density functions (pdfs) f(X\omega (k)) of the data vector X given each class omega (k), due to the difficulty of defining a common statistical model for such heterogeneous data. A possible solution is to adopt non-parametric approaches which rely on the availability of training samples without any assumption about the statistical distributions involved. However, as the multisensor aspect involves generally numerous channels, small training sets make difficult a direct implementation of non-parametric pdf estimation. In this paper, the suitability of the concept of dependence tree for the integration of multisensor information through pdf estimation is investigated. First, this concept, introduced by Chow and Liu, is used to provide an approximation of a pdf defined in an N-dimensional space by a product of N-1 pdfs defined in two-dimensional spaces, representing in terms of graph theoretical interpretation a tree of dependencies. For each land cover class, a dependence tree is generated by minimizing an appropriate closeness measure. Then, a non-parametric estimation of the second order pdfs f(x(j)\x(j),omega (k)) is carried out through the Parzen approach, based on the implementation of two-dimensional Gaussian kernels. In this way, it is possible to reduce the complexity of the estimation, while capturing a significant part of the interdependence among variables. A comparative study with two other non-parametric multisensor data fusion methods, namely: the Multilayer Perceptron (MLP) and K-nearest neighbors (K-nn) methods, is reported. Experimental results carried out on a multisensor (ATM and SAR) data set show the interesting performances of the fusion method based on dependence trees with the advantage of a reduced computational cost with respect to the two other methods.
In modern warfare, radar signals are becoming more and more complex. How to quickly and accurately obtain the category information of target tracks from various radar detection data with huge amount of data, and provi...
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The association of the received signals with exact targets is the most basic and the vital problem in the multitarget applications. In the literature, this problem is known as data association. In the multitarget case...
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The association of the received signals with exact targets is the most basic and the vital problem in the multitarget applications. In the literature, this problem is known as data association. In the multitarget case, after the association of the received signal with the correct targets, these associated signals can be used in many applications such as target localization and target tracking. The errors in data association is caused to increase the error in the following steps which use the wrong associated signals. In this paper, a new initial data association method is proposed for the frequency-only systems in multitarget case. In general, the time, frequency and phase informations of the received signal are used for data association. If the time resolution of the used signals is not good or enough (such as in unmodulated continuous wave (CW) signals), in this case instead of time information, using the frequency information is better.
Question recognition is crucial in Q&A systems. An effective recognition method significantly enhances the accuracy and efficiency of information retrieval. Advances in natural language processing (NLP) technology...
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ISBN:
(纸本)9798400709777
Question recognition is crucial in Q&A systems. An effective recognition method significantly enhances the accuracy and efficiency of information retrieval. Advances in natural language processing (NLP) technology have spurred the development of statement recognition techniques. However, many methods rely on extensive datasets, and numerous sectors struggle to keep pace with intelligent advancements due to data scarcity. Policy-related questions, which often involve a plethora of technical terms, exemplify this challenge. For colloquial questions with intricate structures, models require enhanced natural language understanding capabilities. These models must prioritize key information and filter out irrelevant data, particularly when data availability is limited. To address these issues, this study utilized medical insurance approval items and related questions as data sources. It employed sentence vectors and question structures as analytical frameworks and explored innovative solutions. Specifically, the twin network fine-tuning pre-training model RoBERTa was applied to classify medical insurance items, integrating syntactic structure and question word features to pinpoint question targets. This method outperformed standard text classification models in the medical insurance domain and has potential applicability in other policy-oriented Q&A systems, thereby offering precise services to the public.
Inverse Synthetic Aperture Radar produces images which can be trained to recognize by human operators. Because of varying angular motions (roll, pitch, and yaw), the cross-range resolution is produced. So the Automati...
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Inverse Synthetic Aperture Radar produces images which can be trained to recognize by human operators. Because of varying angular motions (roll, pitch, and yaw), the cross-range resolution is produced. So the Automatic Target Recognition (ATR) of ship can be implemented. The centre-line of ship is an important feature. This paper addresses the problem of centre-line detection and length estimation for ship targets. The aim is to calculate the length of ship for recognition. In order to obtain more accurate results, a new analytical model is proposed, the position of mainmast and the differential Doppler concerning the centre-line is used in the estimation the length of ship. The performance of the proposed algorithm is shown by real data and simulated data.
This paper provids a new method for recongizing quantity of aircraft in radar targets based on neural network for the first *** method turns many duplicate cycle intermediate frequency narrow bandwidth signal received...
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This paper provids a new method for recongizing quantity of aircraft in radar targets based on neural network for the first *** method turns many duplicate cycle intermediate frequency narrow bandwidth signal received by radar which once scans targets into complex envelope signal,caculates its autocorrelation matrix,and autocorrelation matrix characteristic value,make these as primary charactor of radar target recognition In order to decrease coherency between characteristic *** divergence,reduce characteristic space dimensions,compress its primary characteristic data through APEX(Adaptive Principal Component Extraction) algorithm,use BP(Back Propagation ) algorithm reeongnize the compressed data as the quadratic *** trial shows the aircraft number information extract from intermediate frequency narrow bandwidth signal using this method,influenced little by targets space position or posture and it has stronger curb noise *** compressing primary characteristic data applying APEX algorithm,make targets characteristic stable and efficient,and has a relatively well recognition result in applying BP algorithm to target recognition.
Aiming at the inaccurate tracking and the difficulty of the track initialization during multi-target tracking in marine rescue scenes, this article proposes an intelligent processing method for marine tracking data ba...
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ISBN:
(纸本)9781665404136;9781665447300
Aiming at the inaccurate tracking and the difficulty of the track initialization during multi-target tracking in marine rescue scenes, this article proposes an intelligent processing method for marine tracking data based on fuzzy clustering. The measurement information received by the sensor of the measuring device is subjected to the fuzzy clustering process in a period of time, then the entropy from the subjection matrix is used to judge the change in the number of targets. In this way, the number of the target quantity can be determined and the target can be tracked more accurate. This article also analyzes and improves the method through simulation experiments to solve to problems such as inaccurate clustering in real situations. And the method can meet the needs of tracking velocity and tracking accuracy.
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