- 标题
- 摘要
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- 实验方案
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An optimization model for robust FSO network dimensioning
摘要： FSO (Free Space Optics) is a well established wireless optical transmission technology considered as an alternative to radio communications, for example in metropolitan wireless mesh networks. An FSO link is established by means of a laser beam connecting the transmitter and the receiver placed in the line of sight. A major disadvantage of FSO links (with respect to fiber links) is their sensitivity to weather conditions such as fog, rain and snow, causing substantial loss of the transmission power over the optical channel due mostly to absorption and scattering. Thus, although the FSO technology allows for fast and low-cost deployment of broadband networks, its operation will be affected by this sensitivity, manifested by substantial losses in links’ transmission capacity with respect to the nominal capacity. Therefore, a proper approach to FSO network dimensioning should take such losses into account so that the level of carried traffic is satisfactory under all observed weather conditions. In the paper we describe such an approach. We introduce a relevant dimensioning problem and present a robust optimization algorithm for such enhanced dimensioning. A substantial part of the paper is devoted to present a numerical study of two FSO network instances that illustrates the promising effectiveness of the proposed approach.
关键词： Free space optics,Multicommodity flows,Linear and mixed-integer programming,Robust optimization,Resilient and survivable networks,Variable link capacity
更新于2025-09-09 09:28:46
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[IEEE 2018 26th European Signal Processing Conference (EUSIPCO) - Roma, Italy (2018.9.3-2018.9.7)] 2018 26th European Signal Processing Conference (EUSIPCO) - Robust Detection and Estimation of Change-Points in a Time Series of Multivariate Images
摘要： In this paper, we study the problem of detecting and estimating change-points in a time series of multivariate images. We extend existent works to take into account the heterogeneity of the dataset on a spatial neighborhood. The classic complex Gaussian assumption of the data is replaced by a complex elliptically symmetric assumption. Then robust statistics are derived using Generalized Likelihood Ratio Test (GLRT). These statistics are coupled to an estimation strategy for one or several changes. Performance of these robust statistics have been analyzed in simulation and compared to the one associated with standard multivariate normal assumption. When the data is heterogeneous, the detection and estimation strategy yields better results with the new statistics.
关键词： Multivariate Images,Complex Elliptically Symmetric,Robust Change Detection,Image Time Series
更新于2025-09-04 15:30:14
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A Robust and Rapid Camera Calibration Method by One Captured Image
摘要： A robust and rapid camera calibration method is essential in vision measurement. This paper proposes a camera calibration method using a 2.5-D coding target that requires just a single captured image and is capable of identifying the intrinsic and extrinsic parameters of a camera system simultaneously. The calibration target consists of four fixed planes to which coded patterns are attached. The fixed planes of the target prevent the ill condition that arises in Zhang’s method, and they provide four different homography matrices at the same time. The extrinsic parameters of the cameras are calculated using the geometric constraints of the feature circles on each plane. The coded pattern allows the four planes to be distinguished automatically. The proposed method is first verified by comparison experiments with three classical calibration methods. The results confirm that the proposed method has the greatest accuracy and smallest variance of errors. The influences on the calibration results of geometric parameters such as the dihedral angle and the area ratio of the feature circles are then investigated by systematic experiments. This proposed camera calibration method using a single captured image represents a breakthrough in a camera calibration technology and has a broad potential for application to machine vision and vision measurement.
关键词： Camera calibration,target,ill-conditioned system,rapid,robust
更新于2025-09-04 15:30:14
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Desired Compensation Adaptive Robust Control of Electrical-optical Gyro-stabilized Platform with Continuous Friction Compensation Using Modified LuGre Model
摘要： Continuous friction compensation along with other modeling uncertainties is concerned in this paper, to result in a continuous control input, which is more suitable for controller implementation. To accomplish this control task, a novel continuously differentiable nonlinear friction model is synthesized by modifying the traditional piecewise continuous LuGre model, then a desired compensation version of the adaptive robust controller is proposed for precise tracking control of electrical-optical gyro-stabilized platform systems. As a result, the adaptive compensation and the regressor in the proposed controller will depend on the desired trajectory and on-line parameter estimates only. Hence, the effect of measurement noise can be reduced and then high control performance can be expected. Furthermore, the proposed controller theoretically guarantees an asymptotic output tracking performance even in the presence of modeling uncertainties. Extensively comparative experimental results are obtained to verify the effectiveness of the proposed control strategy.
关键词： three-axis electrical-optical gyro-stabilized platform (TEOGSP),desired compensation friction compensation,Adaptive robust control
更新于2025-09-04 15:30:14
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Robust active control based milling chatter suppression with perturbation model via piezoelectric stack actuators
摘要： Milling, as the most widely used processing method, plays an important role in advanced manufacturing. However, milling chatter has severely restricted the development of advanced manufacturing industry. Therefore, it is of great theoretical significance and application value to study the active control of milling chatter. This paper focuses on the design of robust controller for chatter suppression. At first, the milling dynamic equations with active control force are established and simplified with the approximate linear time-invariant model for robust controller design. Then, the perturbation modeling of modal parameters and milling parameters are built and analyzed. Based on the perturbation models, the control algorithm is designed. The numerical simulation in milling process verifies the effectiveness of the designed controller. In order to validate the practical effect, the flank milling and end milling tests are implemented, respectively. The experimental results show that the designed algorithm is able to suppress chatter greatly and lead to the better workpiece surface, which prove the effectiveness and robustness of the designed controller.
关键词： Milling chatter suppression,Piezoelectric stack,Zero order Fourier expansion,Robust active control,Pade approximation,Parameters perturbation
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Robust Design of Low Side Lobe Level Microstrip Antenna Array by Using Lossy Superstrate
摘要： The side lobe level (SLL) suppression technique using lossy superstrate for robust antenna design is proposed. It is conduct by optimizing the dielectric parameters (i.e., relative permittivity, thickness and loss tangent) based on the spectral Green’s function. To validate our method, a 2*2 microstrip antenna array loaded by 2-layer dielectric superstrate is optimized for low SLL. The optimization results show that using lossless dielectric superstrate the optimized SLL can reach -35.2 dB at 35 GHz without considering the fabrication error. Taking the available precision of air gap thickness ((cid:3399)0.02 mm) into consideration, the SLL is raised to -30.4 dB while using lossy superstrate it can be reduced to -35.6 dB at the cost of gain by 5.6 dB. With involving the effect of the feed network in the simulation, the SLL is deteriorated to -34 dB and is lower than -32.3 dB over the operating band from 34.65 GHz to 35.2 GHz.
关键词： robust design,lossy superstrate,Side lobe suppression,dielectric loaded antenna
更新于2025-09-04 15:30:14
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Dual-loop Controller Design Considering Robust Vibration Suppression in Piezo-actuated Stage Systems
摘要： This paper presents a controller design approach considering robust vibration suppression against resonant frequency variations in piezo-actuated systems. In piezo-actuated systems, the improvement of suppression performance with respect to external disturbances and nonlinearities such as hysteresis and creep by the expansion of feedback control bandwidth is indispensable for achieving high-precision positioning. The vibration suppression approach is a key technology for the expansion of bandwidth. From a practical point of view, a minor feedback loop including a simple compensator with a few parameters to increase the design freedom is added to the general feedback control system. In the minor-loop design, the reduction of sensitivity gain at around the resonant frequencies is considered to suppress the residual vibration of the references and disturbances, and the loop-shaping approach based on the frequency domain is adopted to provide an intuitive and practical design guideline. A major-loop for an augmented plant, including the minor-loop, is designed by considering the system stability, servo bandwidth, and settling performance. The proposed approach is veri?ed by conducting experiments using a commercial piezo-actuated stage system.
关键词： loop-shaping,vibration suppression,piezo-actuated stages,robust property,high-precision positioning
更新于2025-09-04 15:30:14
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Infrared Patch-tensor Model with Weighted Tensor Nuclear Norm for Small Target Detection in A Single Frame
摘要： The robust and ef?cient detection of infrared small target is a key technique for infrared search and track systems. Several robust principal component analysis (RPCA) based method have been developed recently, which have achieved state-of-the-art performance. However, there are still two drawbacks: 1) the false alarm ratio would raise under the heavy background clutters and noises, 2) these methods are usually time-consuming and not suitable for real-time processing. To solve this problem, an infrared patch-tensor model based on weighted tensor nuclear norm is proposed in this paper. First, the infrared image is transformed into the infrared patch-tensor (IPT). Considering the sum of nuclear norms (SNN) adopted in the IPT model is not the convex envelope of the tensor rank, and the solution is substantially suboptimal. The tensor nuclear norm is adopted to recover the underlying low-rank background tensor and spare target tensor, and the computation complexity can be reduced dramatically with the help of the tensor Singular Value Decomposition (t-SVD). Moreover, to further suppress the background clutters, a weight tensor is incorporated with tensor nuclear norm to preserve the background edges better. Then the separation between target and background is formulated as a convex weighted tensor RPCA (TRPCA) model. Finally, the proposed model can be solved by the Alternating Direction Method of Multipliers (ADMM). Extensive experiments demonstrate that the proposed model outperforms the other state-of-the-arts in performance and ef?ciency.
关键词： Infrared patch-tensor model,small target detection,weighted tensor robust principal component analysis
更新于2025-09-04 15:30:14
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An Image Copy-Move Forgery Detection Scheme Based on A-KAZE and SURF Features
摘要： The popularity of image editing software has made it increasingly easy to alter the content of images. These alterations threaten the authenticity and integrity of images, causing misjudgments and possibly even affecting social stability. The copy-move technique is one of the most commonly used approaches for manipulating images. As a defense, the image forensics technique has become popular for judging whether a picture has been tampered with via copy-move, splicing, or other forgery techniques. In this paper, a scheme based on accelerated-KAZE (A-KAZE) and speeded-up robust features (SURF) is proposed for image copy-move forgery detection (CMFD). It is dif?cult for most keypoint-based CMFD methods to obtain suf?cient points in smooth regions. To remedy this defect, the response thresholds for the A-KAZE and SURF feature detection stages are set to small values in the proposed method. In addition, a new correlation coef?cient map is presented, in which the duplicated regions are demarcated, combining ?ltering and mathematical morphology operations. Numerous experiments are conducted to demonstrate the effectiveness of the proposed method in searching for duplicated regions and its robustness against distortions and post-processing techniques, such as noise addition, rotation, scaling, image blurring, joint photographic expert group (JPEG) compression, and hybrid image manipulation. The experimental results demonstrate that the performance of the proposed scheme is superior to that of other tested CMFD methods.
关键词： image forensics,accelerated-KAZE (A-KAZE) feature,copy-move forgery detection (CMFD),speeded-up robust features (SURF)
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Nara, Japan (2018.10.9-2018.10.12)] 2018 IEEE 7th Global Conference on Consumer Electronics (GCCE) - Multiple Watermarking for Compressed Sensing with Robust Transmission Applications
摘要： Compressed sensing (CS) is a new research branch in multimedia compressing, which is famous for its superior performance. Due to its digital nature, it is easy to copy and distribute the compressed files in digital format, and the issues relating to digital rights management (DRM) applications would be in urgent need. We propose to hide multiple watermarks in compressed sensing coefficients. Color images consisting of three color planes with high correlations are selected for watermark embedding. Multiple watermarks are embedded into the CS coefficients corresponding to different color planes. With our method, watermarked images are suitable for transmitting over lossy channels, while the copyright of color images can be retained. Simulations have presented the effectiveness for the proposed algorithm.
关键词： color planes,compressed sensing,multiple watermarking,robust transmission
更新于2025-09-04 15:30:14