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Search Results: 1 - 10 of 28215 matches for " Wen Yanping "
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Video Management Using Oracle Database

Wen Yanping,

现代图书情报技术 , 2004,
Abstract: The store and retrieval of digital video documents are important parts of video management. The article analyzes the data model of video in Oracle database, presents an example to show how to store and retrieve the video using Oracle8i interMedia.
Research on Content-based Image Retrieval System

Wen Yanping,

现代图书情报技术 , 2001,
Abstract: The article reviews the development of image retrieval system, and summarizes the technology and current state of image retrieval, especially of content-based image retrieval. It discusses the key technology in Content-based Image Retrieval System(CBIRS). After introducing some famous CBIRS, it gives a new type of CBIRS.
Convolution Back-Projection Imaging Algorithm for Downward-Looking Sparse Linear Array Three Dimensional Synthetic Aperture Radar
Xueming Peng;Weixian Tan;Yanping Wang;Wen Hong;Yirong Wu
PIER , 2012, DOI: 10.2528/PIER12051302
Abstract: General side-looking synthetic aperture radar (SAR) cannot obtain scattering information about the observed scenes which are constrained by lay over and shading effects. Downward-looking sparse linear array three-dimensional SAR (DLSLA 3D SAR) can be placed on small and mobile platform, allows for the acquisition of full 3D microwave images and overcomes the restrictions of shading and lay over effects in side-looking SAR. DLSLA 3D SAR can be developed for various applications, such as city planning, environmental monitoring, Digital Elevation Model (DEM) generation, disaster relief, surveillance and reconnaissance, etc. In this paper, we give the imaging geometry and dechirp echo signal model of DLSLA 3D SAR. The sparse linear array is composed of multiple transmitting and receiving array elements placed sparsely along cross-track dimension. The radar works on time-divided transmitting-receiving mode. Particularly, the platform motion impact on the echo signal during the time-divided transmitting-receiving procedure is considered. Then we analyse the wave propagation, along-track and cross-track dimensional echo signal bandwidth before and after dechrip processing. In the following we extend the projection-slice theorem which is widely used in computerized axial tomography (CAT) to DLSLA 3D SAR imaging. In consideration of the flying platform motion compensation during time-divided transmitting-receiving procedure and parallel implementation on multi-core CPU or Graphics processing units (GPU) processor, the convolution back-projection (CBP) imaging algorithm is proposed for DLSLA 3D SAR image reconstruction. At last, the focusing capabilities of our proposed imaging algorithm are investigated and verified by numerical simulations and theoretical analysis.
3D Bistatic Omega-K Imaging Algorithm for Near Range Microwave Imaging Systems with Bistatic Planar Scanning Geometry
Yaolong Qi;Weixian Tan;Yanping Wang;Wen Hong;Yirong Wu
PIER , 2011, DOI: 10.2528/PIER11090205
Abstract: By introducing bistatic geometry to near range microwave imaging systems, this paper proposes a near range three dimensional (3D) bistatic imaging geometry based on planar scanning aperture and establishes corresponding echo model. Then, the paper deduces the 3D bistatic Omega-K imaging algorithm based on implicit spectral decomposition, in which the impacts of residual phase, including position displacement, range, azimuth and elevation defocusing, are analyzed and compensated. Finally, the 3D bistatic imaging geometry and algorithm are investigated and verified via numerical simulations and experiments using a near range imaging system.
A Novel Spherical-Wave Three-Dimensional Imaging Algorithm for Microwave Cylindrical Scanning Geometries
Weixian Tan;Wen Hong;Yanping Wang;Yirong Wu
PIER , 2011, DOI: 10.2528/PIER10100307
Abstract: With the increasing threat of terrorism in recent years, the detection of concealed weapons, plastic bombs and other contraband at secure locations attracts more and more countries' attention all over the world. Three-dimensional (3D) microwave imaging surveillance systems, allowing for acquisition of full 3D microwave images of volumetric scatters of human body, have been developed for security applications. In this paper, we firstly propose a 3D imaging algorithm which not only accounts for the free space propagation losses and wavefront curvature but also avoids 3D interpolation in the 3D wavenumber domain without suffering from any approximations and truncation errors. Then, the sampling constraints and the resolution issues associated with proper and alias-free implementation of the 3D reconstruction are analyzed. Finally, the focusing capabilities of our proposed imaging algorithm are investigated and verified by means of numerical simulations as well as theoretical analysis, and an approach for better displaying projected images is examined.
A Three-Dimensional Range Migration Algorithm for Downward-Looking 3D-SAR with Single-Transmitting and Multiple-Receiving Linear Array Antennas
Du Lei,Wang Yanping,Hong Wen,Tan Weixian
EURASIP Journal on Advances in Signal Processing , 2010,
Abstract: This paper presents a three-dimensional (3D) range migration algorithm (RMA) suitable for downward-looking 3D-SAR with single-transmitting and multiple-receiving linear array antennas (STMR-LAA). As the round-trip range equation in 3D-SAR with STMR-LAA is a dual square root, the signal spectrum in 3D wavenumber domain contains nonlinear phase terms besides constant and linear phase terms. In this paper, the approximate expression of the signal spectrum is derived by expanding the implicit phase term to its Taylor series. Then the constant and nonlinear phase terms are calculated and compensated by multiplying the wavenumber filters. Finally, a 3D wavenumber mapping is proposed to make the signal evenly sampled in 3D wavenumber domain. Some simulating results are presented to validate the correctness of the analysis and the feasibility of the algorithm. In addition, the required accuracy on the platform position is analyzed at the end of the paper.
Autonomous Navigation Airborne Forward-Looking SAR High Precision Imaging with Combination of Pseudo-Polar Formatting and Overlapped Sub-Aperture Algorithm
Xueming Peng,Yanping Wang,Wen Hong,Weixian Tan,Yirong Wu
Remote Sensing , 2013, DOI: 10.3390/rs5116063
Abstract: Autonomous navigation airborne forward-looking synthetic aperture radar (SAR) observes the anterior inferior wide area with a short cross-track dimensional linear array as azimuth aperture. This is an application scenario that is drastically different from that of side-looking space-borne or air-borne SAR systems, which acquires azimuth synthetic aperture with along-track dimension platform movement. High precision imaging with a combination of pseudo-polar formatting and overlapped sub-aperture algorithm for autonomous navigation airborne forward-looking SAR imaging is presented. With the suggested imaging method, range dimensional imaging is operated with wide band signal compression. Then, 2D pseudo-polar formatting is operated. In the following, azimuth synthetic aperture is divided into several overlapped sub-apertures. Intra sub-aperture IFFT (Inverse Fast Fourier Transform), wave front curvature phase error compensation, and inter sub-aperture IFFT are operated sequentially to finish azimuth high precision imaging. The main advantage of the proposed algorithm is its extremely high precision and low memory cost. The effectiveness and performance of the proposed algorithm are demonstrated with outdoor GBSAR (Ground Based Synthetic Aperture Radar) experiments, which possesses the same imaging geometry as the airborne forward-looking SAR (short azimuth aperture, wide azimuth swath). The profile response of the trihedral angle reflectors, placed in the imaging scene, reconstructed with the proposed imaging algorithm and back projection algorithm are compared and analyzed.
Airborne Downward Looking Sparse Linear Array 3-D SAR Heterogeneous Parallel Simulation
Xueming Peng,Yanping Wang,Wen Hong,Weixian Tan,Yirong Wu
Remote Sensing , 2013, DOI: 10.3390/rs5105304
Abstract: The airborne downward looking sparse linear array three dimensional synthetic aperture radar (DLSLA 3-D SAR) operates nadir observation with the along-track synthetic aperture formulated by platform movement and the cross-track synthetic aperture formulated by physical sparse linear array. Considering the lack of DLSLA 3-D SAR data in the current preliminary study stage, it is very important and essential to develop DLSLA 3-D SAR simulation (echo generation simulation and image reconstruction simulation, including point targets simulation and 3-D distributed scene simulation). In this paper, DLSLA 3-D SAR imaging geometry, the echo signal model and the heterogeneous parallel technique are discussed first. Then, heterogeneous parallel echo generation simulation with time domain correlation and the frequency domain correlation method is described. In the following, heterogeneous parallel image reconstruction simulation with two imaging algorithms, e.g., 3-D polar format algorithm, polar formatting and L1 regularization algorithm is discussed. Finally, the point targets and the 3-D distributed scene simulation are demonstrated to validate the effectiveness and performance of our proposed heterogeneous parallel simulation technique. The 3-D distributed scene employs airborne X-band DEM and P-band Circular SAR image of the same area as simulation scene input.
Ensemble-based active learning for class imbalance problem  [PDF]
Yanping Yang, Guangzhi Ma
Journal of Biomedical Science and Engineering (JBiSE) , 2010, DOI: 10.4236/jbise.2010.310133
Abstract: In medical diagnosis, the problem of class imbalance is popular. Though there are abundant unlabeled data, it is very difficult and expensive to get labeled ones. In this paper, an ensemble-based active learning algorithm is proposed to address the class imbalance problem. The artificial data are created according to the distribution of the training dataset to make the ensemble diverse, and the random subspace re-sampling method is used to reduce the data dimension. In selecting member classifiers based on misclassification cost estimation, the minority class is assigned with higher weights for misclassification costs, while each testing sample has a variable penalty factor to induce the ensemble to correct current error. In our experiments with UCI disease datasets, instead of classification accuracy, F-value and G-means are used as the evaluation rule. Compared with other ensemble methods, our method shows best performance, and needs less labeled samples.
Study for System of Nonlinear Differential Equations with Riemann-Liouville Fractional Derivative  [PDF]
Yanping Zheng, Wenxia Wang
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.47A002

In this work, we study existence theorem of the initial value problem for the system of fractional differential equations \"\"where Dα denotes standard Riemann-Liouville fractional derivative, 0 < α < 1, \"\" \"\"and A  is a square matrix. At the same time, power-type estimate for them has been given.

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