- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - An Interior Point Method for Nonnegative Sparse Signal Reconstruction
摘要： We present a primal-dual interior point method (IPM) with a novel preconditioner to solve the (cid:96)1-norm regularized least square problem for nonnegative sparse signal reconstruction. IPM is a second-order method that uses both gradient and Hessian information to compute effective search directions and achieve super-linear convergence rates. It therefore requires many fewer iterations than first-order methods such as iterative shrinkage/thresholding algorithms (ISTA) that only achieve sub-linear convergence rates. However, each iteration of IPM is more expensive than in ISTA because it needs to evaluate an inverse of a Hessian matrix to compute the Newton direction. We propose to approximate each Hessian matrix by a diagonal matrix plus a rank-one matrix. This approximation matrix is easily invertible using the Sherman-Morrison formula, and is used as a novel preconditioner in a preconditioned conjugate gradient method to compute a truncated Newton direction. We demonstrate the efficiency of our algorithm in compressive 3D volumetric image reconstruction. Numerical experiments show favorable results of our method in comparison with previous interior point based and iterative shrinkage/thresholding based algorithms.
关键词： nonnegative sparse,3d volumetric image reconstruction,primal-dual preconditioned interior point method,(cid:96)1-norm regularized optimization,compressive sensing
更新于2025-09-23 15:22:29
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Estimation of the number of endmembers in hyperspectral data using a weight-sequence geometry method
摘要： The terrestrial reflection or emission spectrum obtained by the remote sensor is recorded in units of pixels. In most cases, a pixel usually contains many types of terrains. This pixel is a mixed pixel, and each of the terrains in the mixed pixels is called 'endmember'. Estimating the number of endmembers is a significant step in many hyperspectral data mining techniques, such as target classification and endmember extraction. The paper proposes a separative detection method by the use of a weight-sequence geometry to estimate the number of endmembers. This method projects the spectral matrix into the orthogonal subspace by eigenvalue decomposition at first. Then, on the basis of the normalized eigenvalue sequence, the separative detection method innovatively uses a geometric criterion to find the separation point between the main factors and minor factors. Finally, the number of endmembers is determined by the sequence of the 'separation point'. Validation through a series of simulated and real hyperspectral data, it indicates that the proposed method can accurately and rapidly detect the number of endmembers in the hyperspectral data without any prior information. In addition, the new method is also applicable to the ultra-high resolution remote spectral data in the future.
关键词： number of endmembers,Hyperspectral data,separative detection method,hyperspectral unmixing
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - High Precision Control of an Inertially Stabilized Platform for Aerial Remote Sensing Applications
摘要： Inertially stabilized platform (ISP) is an important component of the aerial remote sensing system, which is used to make the imaging sensors stable so as to obtain the high quality images by disturbance rejection. To improve the stabilization accuracy of an ISP under multi-source disturbance environment, an active disturbance rejection control (ADRC) control scheme is prosed, which is composed of three components, i.e., a tracking differentiator (TD), a nonlinear state error feedback (NLSEF) and an extended state observer (ESO). To verify the method, the experiments are carried out. The results show that the proposed method can improve the stabilization accuracy due to significant ability in disturbances rejection.
关键词： Inertially stabilized platform,empirical method,active disturbance rejection control,disturbances rejection
更新于2025-09-23 15:22:29
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A methodology for topology optimization based on level set method and its application to piezoelectric energy harvester design
摘要： Compared to a density based procedure, the level set method can acquire a clear boundary without any intermediate density elements, and has become a topical issue in topology optimization studies. In this method, the material properties of the discretized elements are usually defined as the design variables, giving rise to the so called discrete or sawtooth topologies. In this paper, a topology optimization methodology based on level-set method (LSM) and radial basis function (RBF) is proposed. To enhance the performance of the LSM, an improved material interpolation model is proposed. The RBF based post-processor is proposed to smooth the preliminary optimized topology. The proposed method is applied to the topology design of a piezoelectric energy harvester. The effect of different penalization factors is compared and analyzed. The numerical results validate the feasibility and effectiveness of the proposed method.
关键词： Coupled problems,topology optimization,level set method
更新于2025-09-23 15:22:29
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[IEEE 2018 Prognostics and System Health Management Conference (PHM-Chongqing) - Chongqing, China (2018.10.26-2018.10.28)] 2018 Prognostics and System Health Management Conference (PHM-Chongqing) - A Remaining Useful Life Prediction Method for T/R Module Based on Index Similarity
摘要： T/R module is an important part of large phased array radar antenna array, the remaining useful life (RUL) prediction is of great significance for equipment support personnel to master current health status and improve maintenance support ability. At first, the key indexes of multi-state degradation are extracted by association rule, by calculating the similarity of the key indexes and combining the RUL of similar samples, the RUL information corresponding to the key indexes is obtained. The RUL prediction results of T/R module are obtained according to the weight of different indexes. The practicability and effectiveness of the proposed method are verified by example analysis and comparison, which provide theoretical guidance for the RUL prediction of electronic equipment. The proposed method is of great significance for maintenance support personnel of the military equipment to plan the maintenance resources reasonably and improve the combat effectiveness of the equipment.
关键词： index,T/R module,association rule,multi-state degradation,remaining useful life prediction,entropy weight method
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - Radar Cross Section of Modified Target Using Gaussian Beam Methods: Experimental Validation
摘要： The aim of this paper is to study the Radar Cross Section (RCS) of modified radar targets (plate with notch) using Gaussian Beam techniques. The Gaussian methods used in this work are Gaussian Beam Summation (GBS) and Gaussian Beam Launching (GBL). We establish the theoretical formulation of the GBS and GBL techniques and analyze the influence of the main Gaussian beam parameters on the variation of the scattered field. Then, we present the simulations of RCS. The numerical results are compared with PO, MoM methods, and also with experimental measurements performed in the anechoic chamber at Lab-STICC (ENSTA Bretagne).
关键词： Radar Cross Section (RCS),Physical Theory of Diffraction (PTD),Physical Optic (PO),Gaussian Beam Summation (GBS),Gaussian Beam Launching(GBL),Method of Moment (MoM)
更新于2025-09-23 15:22:29
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Hydration accelerator and photocatalyst of nanotitanium dioxide synthesized via surfactant-assisted method in cement mortar
摘要： To develop TiO2-based cement materials, the effect of TiO2 on the cement hydration and photocatalytic reaction should be investigated. The phase, size and shape of TiO2 are important factors for better understanding its application in cement. TiO2 nanoparticles were synthesized by a surfactant-assisted, reverse micelle method to control phase, size and shape by three selected surfactants namely: sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and TritonX-100. The synthesized TiO2 nanoparticles were characterized by XRD, SEM and TEM for observation of phase, size and shape. The modified micro structures of admixed cements with the different synthesized TiO2 nanoparticles incorporated were also examined by SEM. Particularly, the hydration process and photocatalytic reaction of the cement mixture were evaluated by heat flow calorimetry and methylene blue (MB) degradation, respectively. Results showed that anatase-rich and smaller size TiO2 nanoparticles provided accelerated cement hydration and the ability to degrade MB photocatalytically at the surface of admixed-TiO2 cement.
关键词： Surfactant-assisted method,Photocatalytic activity,Hydration,Cement,Titanium dioxide nanoparticle
更新于2025-09-23 15:22:29
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Synthesis of broad yellow phosphors by co-doping and realization of high quality of white light
摘要： In order to obtain high quality white light, we synthesized yellow phosphors by doping europium and other lanthanoids such as holmium and lutetium. We successfully obtained yellow phosphors with green emissions with a wavelength of 510 nm for Li2SrSiO4 by co-doping europium and holmium. Unlike single doping of europium, a lower reduction temperature seemed to be preferable. When we simulated the chromaticity of white light at 5000 K, achieved by mixing blue light, which was used for excitation, and this phosphor, it resulted in better quality than commercially available products.
关键词： europium,sol-gel method,white light,Co-doping
更新于2025-09-23 15:22:29
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Enhancement of flexoelastic ratio of nematic liquid crystal doped with hydrogen-bonded bimesogen molecules
摘要： We synthesized a new liquid crystal (LC) dopant 4-[7-(4′-Cyanobiphenyl-4-yl)hexyloxy]bezoic acid (CBO7OBA) which can form dimers by hydrogen-bonding. We mixed the hydrogen-bondable CBO7OBA dopants with commercial nematic liquid crystal (NLC) mixtures and investigated the change of the flexoelastic ratio of the mixture. The flexoelastic ratio of the CBO7OBA-doped NLC mixture was increased up to 4.7 C/Nm, while that of the pure NLC was 2.0 C/Nm at room temperature. The greater flexoelastic ratio of the CBO7OBA-doped NLC mixture is thought to be due to the bent-shape and the large dipole moment of the CBO7OBA molecules.
关键词： Flexoelectric effect,Flexoelectro-optic method,Flexoelastic ratio,Bimesogenic liquid crystal
更新于2025-09-23 15:22:29
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[IEEE 2018 5th International Conference on Information Technology, Computer, and Electrical Engineering (ICITACEE) - Semarang (2018.9.27-2018.9.28)] 2018 5th International Conference on Information Technology, Computer, and Electrical Engineering (ICITACEE) - Compressive Sensing Approach with Double Layer Soft Threshold for ECVT Static Imaging
摘要： Electrical Capacitance Volume Tomography (ECVT) is a capacitance based tomography technology which is developed since its advantages on non-invasive properties, low energy, and portability. One of the challenge on developing this tomography technology is on its imaging algorithm. Naturally the imaging method forms under-determined linear system which is indicated by dimension of the measurement is much smaller compared to the projected value dimension. Mathematically it implies ill-posed inverse problem. Therefore Compressive Sensing framework is used to solve the corresponding inverse problem. To improve the accuracy of the predicted image reconstruction, new threshold approach, Double Layer Soft Threshold, is proposed and attached to the proposed Compressive Sensing based ECVT imaging method. The simulations results show that the proposed method is able to improve the conventional ECVT imaging method, Iterative Linear Back Projection (ILBP), by significantly eliminating the elongation error.
关键词： Imaging method,Electrical Capacitance Volume Tomography,Compressive Sensing,Double Layer Soft Threshold
更新于2025-09-23 15:22:29