Search

Based on Gaussian distribution, a method for modelling targets is proposed. The trajectories of infrared targets are predicted by Kalman filtering. The Munkres version of the Hungarian algorithm is...

Most of existing particle filtering-based video target tracking algorithms are in Euclidean space, when object posture and scale size changes, and to track high dimensional system, it is difficult to guarantee the tracking effect. This paper describes the covariance descriptor to represent the object image region, the geometric deformation of the object image region can be realized by an affine transformation, and the affine transformation matrix is one element of the Lie group. Then particle filter algorithm based on lie group of manifold is proposed , the video tracking system state lies directly on a low dimensional manifold, state samples are drawn moving on the manifold geodesics, thus state space of intrinsic geometrical characteristic can be in full use, which provides a new idea for improving the tracking efficiency and robustness. Simulation results show that object in the case of geometric deformation including scale size changes, rotating, etc. The proposed manifold particle filtering algorithm can still realize target tracking well and improve the real-time performance.

The mandrel frame is the most commonly used sensitizing structure for scalar fiber hydrophones, and its material properties and structure directly affect hydrophone performance. The finite element simulation model of a hydrophone is established based on the principle of acoustic-structure interaction. Additionally, the influences of the material and structure on hydrophone sensitivity and the working bandwidth are analyzed in detail. The results show that the sensitivity and bandwidth of the hydrophone restrict each other, and the inner mandrel resonance exerts the main limitation on the bandwidth. Increasing the inner mandrel thickness and reducing the inner mandrel radius can widen the working bandwidth while maintaining sensitivity. The accuracy of the model is verified by via experiments in a lake.

For mixed-signal systems, identifying the analog and digital circuit blocks in the transistor-level netlist has many benefits for system analysis and verification. However, existing approaches still have difficulty handling large mixed-signal designs with millions of transistors, especially when multiple analog structure patterns are included. In this paper, we propose an efficient structure recognition methodology to support analyzing highly complex designs with various circuit structures and different devices. In order to tackle the complexity of real cases, a hierarchical partition-based analysis methodology and an encoding-based fast screening technique are proposed in this work. To correctly ascertain the boundary of analog and digital structures, we propose an enhanced direct current connection (DCC) partition method and combine it with the analog structure analysis flow. The non-transistor devices, such as resistors and capacitors, are also included in our recognition flow to improve the recognition capability and accuracy. As demonstrated with two industrial cases, the behavioral models generated from the structure recognition results do help to improve the efficiency of the AMS system verification.

We propose and demonstrate a high-frequency interferometric optical fiber hydrophone based on acoustic resonance isolation. Novel air chambers are introduced into common type of mandrel sensitization structure to prevent acoustic resonance which occurs inside the inner cylindrical cavity of hydrophone frame at specific high frequency acoustic filed. 1kHz-30kHz frequency response of this new kind of hydrophone is measured in a lake. Experiment shows that, by this acoustic structure optimization, the working frequency bandwidth of optical fiber hydrophone, whose acoustic pressure sensitivity is-147dB, is expanded from 10kHz to above 30kHz.

In this paper, a novel phase-sensitive optical time-domain reflectometry ( Φ -OTDR) based on the optimized dual-pulse heterodyne detection scheme (DHDS) is proposed, which is designed to implement distributed vibration sensing with low phase noise and high sensitivity. The optimized DHDS employs an unbalanced interferometer to separate a light pulse into dual probe pulses so that they are generated by the laser at the same time. This ensures that the measurement sensitivity of a phase-interrogation-based Φ -OTDR can be improved simply by increasing the space interval of the dual probe pulses while the phase noise of the Φ -OTDR does not deteriorate. In addition, the proposed DHDS utilizes only one acousto-optic modulator (AOM) to shift the frequencies of the dual probe pulses so as to eliminate the effects of frequency shift jitters, and thus guarantees low phase noise level of a Φ -OTDR. The distributed vibration sensing performances of the Φ -OTDR with the proposed DHDS are theoretically and experimentally studied in terms of multi-event signal restoration and phase noise level. The proposed approach solves the contradiction between the measurement sensitivity and phase noise of a Φ -OTDR and promotes the Φ -OTDR to the applications of distributed weak vibration sensing.

Infrared image recognition technology can work day and night and has a long detection distance. However, the infrared objects have less prior information and external factors in the real-world environment easily interfere with them. Therefore, infrared object classification is a very challenging research area. Manifold learning can be used to improve the classification accuracy of infrared images in the manifold space. In this article, we propose a novel manifold learning algorithm for infrared object detection and classification. First, a manifold space is constructed with each pixel of the infrared object image as a dimension. Infrared images are represented as data points in this constructed manifold space. Next, we simulate the probability distribution information of infrared data points with the Gaussian distribution in the manifold space. Then, based on the Gaussian distribution information in the manifold space, the distribution characteristics of the data points of the infrared image in the low-dimensional space are derived. The proposed algorithm uses the Kullback-Leibler (KL) divergence to minimize the loss function between two symmetrical distributions, and finally completes the classification in the low-dimensional manifold space. The efficiency of the algorithm is validated on two public infrared image data sets. The experiments show that the proposed method has a 97.46% classification accuracy and competitive speed in regards to the analyzed data sets.

We report in this paper a miniature adjustable-focus camera module integrated with a solid tunable lens driven by MEMS-thermal actuators. Thanks to the compact structures of the MEMS actuators and the optical-power-variation capability of such solid tunable lenses, such a camera module shows great potential in various applications, especially in tiny underwater imaging systems where an optical zoom or focus-tuning function is required. The camera module presented in this paper consists of a solid tunable lens for optical power tuning, two identical MEMS-thermal actuators for lens component driving and one commercial CMOS chip for image recording, assisted with necessary mechanical parts for supporting and housing. We first introduce the optimal design of the solid tunable lens which consists of two freeform components moving in the direction perpendicular to the optical axis, and subsequently, the MEMS thermal actuators which consist of V-shaped micro beams. The lens components are fabricated by the technique of single-point diamond turning followed by the PMDS modelling process while the MEMS-thermal actuators are materialized by a commercial MUMPS process. The static performance of the designed system, including the temperature distribution, displacement-versus-voltage curve and the optical tuning capability, is characterized in detail, together with the dynamic responding speed, hysteresis and imaging performance stability during tuning. Results show that a maximum output displacement of 135 μm is achieved by the optimized MEMS-thermal actuator with a driving voltage of 10V, and consequently a focal length tuning range from 9.2 to 7.9 mm with a responding speed of about 90 ms is realized by the solid tunable lens. The highest temperate on the actuator is about 690 K during the operation while the temperate increase on the lens components is found to be about 30 K, which guarantees the optical performance stability. Targets placed at different object distances are clearly focused by the assembled miniature camera module with various driving voltages, which demonstrate its adjustable focus capability. Such miniature adjustable-focus camera modules show promising future in underwater applications due to their compact structures and optical-power-variation capability.

We present ALMA observations of the $98.5~\mathrm{GHz}$ dust continuum and the $\mathrm{^{13}CO}~J = 1 - 0$ and $\mathrm{C^{18}O}~J = 1 - 0$ line emissions of the protoplanetary disk associated with HD~142527. The $98.5~\mathrm{GHz}$ continuum shows a strong azimuthal-asymmetric distribution similar to that of the previously reported $336~\mathrm{GHz}$ continuum, with a peak emission in dust concentrated region in the north. The disk is optically thin in both the $98.5~\mathrm{GHz}$ dust continuum and the $\mathrm{C^{18}O}~J = 1 - 0$ emissions. We derive the distributions of gas and dust surface densities, $\Sigma_\mathrm{g}$ and $\Sigma_\mathrm{d}$, and the dust spectral opacity index, $\beta$, in the disk from ALMA Band 3 and Band 7 data. In the analyses, we assume the local thermodynamic equilibrium and the disk temperature to be equal to the peak brightness temperature of $\mathrm{^{13}CO}~J = 3 - 2$ with a continuum emission. The gas-to-dust ratio, $\mathrm{G/D}$, varies azimuthally with a relation $\mathrm{G/D} \propto \Sigma_\mathrm{d}^{-0.53}$, and $\beta$ is derived to be $\approx 1$ and $\approx 1.7$ in the northern and southern regions of the disk, respectively. These results are consistent with the accumulation of larger dust grains in a higher pressure region. In addition, our results show that the peak $\Sigma_\mathrm{d}$ is located ahead of the peak $\Sigma_\mathrm{g}$. If the latter corresponds to a vortex of high gas pressure, the results indicate that the dust is trapped ahead of the vortex, as predicted by some theoretical studies., Comment: 32 pages, 15 figures

We present the first sub-arcsecond images of 49 Ceti in the [C I]3P1-3P0 emission and the 614 micron dust continuum emission observed with ALMA, as well as that in the CO(J=3-2) emission prepared by using the ALMA archival data. The spatial distribution of the 614 micron dust continuum emission is found to have a broad-ring structure with a radius of about 100 au around the central star. A substantial amount of gas is also associated with 49 Ceti. The [C I] emission map shows two peaks inside the dust ring, and its overall extent is comparable to that of the dust continuum emission and the CO emission. We find that the [C I]/CO(J=3-2) intensity ratio significantly varies along the major axis. The ratio takes the minimum value of 1.8 around the dust peak position, and increases inwards and outwards. The enhanced ratio around the central star (~3) likely originates from the stellar UV radiation, while that in the outer disk (~10) from the interstellar UV radiation. Such complex distributions of the [C I] and CO(J=3-2) emission will be a key to understand the origin of the gas in 49 Ceti, and will also provide a stringent constraint on physical and chemical models of gaseous debris disks., 21 pages, 7 figures, 1 table; accepted for publication in ApJ

Four species of the genus Eretmocera Zeller, 1852 from China are reviewed. Three species are described as new: Eretmocera yingjiangensis Li, sp. nov., E. octopunctata Li, sp. nov. and E. artemisiae Li, sp. nov. Eretmocera impactella (Walker, 1864) is redescribed based on specimens founded on Yunnan, China. Photographs of adults and genitalia are provided, and a key to the Eretmocra species that occur in China is given.

The mechanical properties of multi-use multilayers including the apparent tensile strength are important for estimating the multilayer's reliability. Yet in biaxial flexure, there exist enhanced or weakened performances when measuring apparent strength of laminates, resembling those found in uniaxial tensile load. In this paper, a model is proposed to predict the effect of thin film on apparent strength in terms of the applied tensile load. Six cases are discussed to characterize the enhanced or weakened performances of laminated membranes by introducing Apparent Strength Enhancement Factor (ASEF). It is notable that the ASEF is independent from thermal residual stresses in the case where substrate can continue to sustain the entire external load solely when film cracks first. Experimental results show clearly that fracture stress of laminated half-cell is lower than that of corresponding anode substrate. The prediction capability of the proposed model has been validated by the experimental results, though additional experiments are still required in order to critically assess the model's predictions over a range of bilayer laminates. In addition, comparison of the reverse mechanical performances between different types of loading reveals that the present analysis is significative for design and discussion of the mechanical integrity for multi-use multilayers. Keywords: Multilayer laminated systems, Residual stresses, Apparent fracture strength, Strength enhancement factor

In a faunal study of insects in the Habahu National Nature Reserves of Ningxia, seven species of the genus Scythris of Scythrididae are recognized. One species, S. fustivalva Li, sp. nov., is described as new; five species are newly recorded in China: S. caballoides Nupponen, 2009, S. mikkolai Sinev, 1993, S. orientella Sinev, 2001, S. pallidella Passerin d'Entrèves et Roggero, 2006 and S. sinevi Nupponen, 2003. Photos of adults and genitalia are provided, and a list of Scythrididae in China is given.

As the most important component in steel structure engineering, the working dimensions and machining accuracy of junction plates often have to vary to suit the requirements of different structures and complex stress state. This thesis has presented a common design method which, by confirming all details of the plate, parameterizes its machining features including property, application range, contour, plate thickness, welding seam, arrangements of connecting bores, bore diameters and position, and makes flexible combinations to adapt to different linking patterns as orthogonal, oblique, slope changes, etc. The junction plate designed in this way has become an information model that covers all steps in junction plate designing.

When to test the failure stress of Solid Oxide Fuel Cell system, bending approach is consider as one of the convenient ways. The failure stresses are calculated by the elasticity multi -layered theory, in which the neutral axis is determined by the mechanical properties of materials and the thickness of the layers. When cooling from the sintered temperature, residual stresses arise in the multi-layered system due to the mismatch of the thermal expansion coefficients, in this case, the thermal elastic theory point out that the neutral axis depends on residual stress. In this paper, the effect of residual stress on the shift of neutral axis and consequently the failure stress of SOFCs presented, the finite element method was also employed to calculate the SOFCs before and after reduction. The results show that the residual stresses has a distribution along the thickness of the layers, the neutral axis also shifts with the residual stress and the external bending moment, when to test and value the bending stress, the shift of neutral axis should be considered.

In the present paper, integrity assessment is made to the defects in weld metal zone of pressure piping of X52 steel using the two basic routes, FAD and CDF, which are provided in the European flaw assessment procedure SINTAP. Based on the experimental data various analysis levels of SINTAP are discussed, including the uncommonly used J-integral level in particular. Furthermore, to meet the need of the reliability assessment of pressure piping containing defects in engineering applications, probabilistic procedures are employed to obtain several probability curves with given survivability on the J-integral level with respect to the great scatter of the tested fracture toughness which is required in the J-integral level analysis.

Genetic variation plays a significant role in maintaining the evolutionary potential of a species. Comparing the patterns of adaptive and neutral diversity in extant populations is useful for understanding the local adaptations of a species. In this study, we determined the fine-scale genetic structure of 6 extant populations of the giant panda (Ailuropoda melanoleuca) using mtDNA and DNA fingerprints, and then overlaid adaptive variations in 6 functional Aime-MHC class II genes (DRA, DRB3, DQA1, DQA2, DQB1, and DQB2) on this framework. We found that: (1) analysis of the mtDNA and DNA fingerprint-based networks of the 6 populations identified the independent evolutionary histories of the 2 panda subspecies; (2) the basal (ancestral) branches of the fingerprint-based Sichuan-derived network all originated from the smallest Xiaoxiangling (XXL) population, suggesting the status of a glacial refuge in XXL; (3) the MHC variations among the tested populations showed that the XXL population exhibited extraordinary high levels of MHC diversity in allelic richness, which is consistent with the diversity characteristics of a glacial refuge; (4) the phylogenetic tree showed that the basal clades of giant panda DQB sequences were all occupied by XXL-specific sequences, providing evidence for the ancestor-resembling traits of XXL. Finally, we found that the giant panda had many more DQ alleles than DR alleles (33∶13), contrary to other mammals, and that the XXL refuge showed special characteristics in the DQB loci, with 7 DQB members of 9 XXL-unique alleles. Thus, this study identified XXL as a glacial refuge, specifically harboring the most number of primitive DQB alleles.

Inhomogeneous re-oxidation, which causes graded NiO content along anode thickness, has been confirmed to be a key reason for Ni-based cell cracking during redox progress. In this paper, an analytical model is developed to estimate the impact of inhomogeneous re-oxidation on Ni-based solid oxide fuel cell (SOFC) oxidation resistance. And experiments, in which the SOFC was partially re-oxidized, were implemented for model trial. Model results show that electrolyte internal stress can be significantly reduced (from 367 MPa to 135 MPa, when the oxidation degree is 60%), and the electrolyte can remain intact even when the oxidation degree reaches about 70%, if the anode was re-oxidized uniformly. This impact of inhomogeneous re-oxidation on stress in the electrolyte decreases as the anode thickness increases. Scanning electron microscopic (SEM) images of partially oxidized anode cross-sections confirmed that Ni oxidation was inhomogeneous, in which the outer regions of the anode became almost fully oxidized, while the inner regions remained metallic. And the inhomogeneity increases with the redox times. Consequently, it is important to avoid gradients in NiO content during oxidation progress to prevent cell cracking.

著者人数: 35名, Accepted: 2016-04-04, 資料番号: SA1160183000