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In the current study, a comprehensive numerical model for analyzing the vibrational characteristics of braided fiber-reinforced composite (BFRC) rotating annular plate with perforations under diverse boundary constraints was introduced. This model employs the differential quadrature finite element method (DQFEM), which was developed based on the first-order shear deformation theory (FSDT) and coordinate transformation approach. The BFRC material, specifically a two-dimensional biaxial orthogonal fabric, was utilized to fabricate the annular plate with two distinct types of holes: circular and sector-shaped. The model's convergence, accuracy, numerical stability, and reliability were confirmed through comparative assessments utilizing data from the literature, from ABAQUS software, and from experimental findings. The analysis focuses on studying the influences of structural properties, material parameters, and boundary restraints on the frequencies of vibration for BFRC rotating annular plates with holes. This theoretical model helps provide scientific basis and technical guidance for the stability and lightweight design of rotating annular plates, such as rotor structures in aircraft engines. [ABSTRACT FROM AUTHOR]

Humans perceive their surrounding environments largely through their experiences of sight and hearing. The perceived environmental information then brings on neurophysiological changes, so as to influence human emotions. These mutually influenced relations have been widely utilized by many environmental psychologists to explore potential avenues for improving human emotions through design interventions. However, to date, no efficient and accurate way has been established to describe these relationships. Inspired by Russell's model of emotion, this study aims to develop an efficient process that uses coordinate mapping and can intuitively describe the impact of visual-aural perceptive attributes on human emotions. Taking typical urban green spaces (UGSs) in Chengdu as examples, this study first measured the visual and aural characteristics of study sites perceived by people and their emotional responses. The study then established the use of emotional status on a coordinate axis, allowing each visual-aural attribute corresponding to each emotional response to be projected onto the coordinates. Results suggested that the dataset composed of 279 evaluations could be classified into three distinct types of visual-aural settings and the distribution of emotions is evidently varied in different settings. It was found that aesthetic and order of visual aspects as well as eventful and harmonious soundscape in environments are more likely to make people feel pleasure, while openness and layering of the visual landscape can easily arouse people's positive status. The research outcome broadens the practical path of soundscape research, centring on human emotions, experiences and feelings, such as the pleasantness and arousal raised in Russell's theory of emotion. The study also makes an empirical contribution to the design of UGSs based on multi-sensory perception and serves the purpose of improving people's environmental experiences. [ABSTRACT FROM AUTHOR]

Summary: A Vienna rectifier is a kind of three‐phase converter with complex operation constraints. Traditional control methods suffer from poor dynamic responses and total harmonic distortion (THD), particularly when operating with adjustable wide‐range power. A novel low‐complexity model predictive control (LC‐MPC) algorithm is proposed based on the optimal switching vector sequence in this paper. First, a model predictive optimization control (MPOC) method is designed to search for the voltage vector sequence and its acting time. Second, the equivalent transformation and coordinate mapping of MPOC are efficiently achieved through the derived correlation factors and lookup table. Supported by the correlation factors, the redundant objective function calculation and repetitive online optimization are eliminated. Meanwhile, the simplified optimal over‐modulation strategy is implemented. Finally, the effectiveness and superiority of the algorithm are verified by comparative experiments. The results show that the proposed LC‐MPC is beneficial in terms of the computation time, dynamic response, over‐modulation, and harmonic content reduction. [ABSTRACT FROM AUTHOR]

Humans perceive their surrounding environments largely through their experiences of sight and hearing. The perceived environmental information then brings on neurophysiological changes, so as to influence human emotions. These mutually influenced relations have been widely utilized by many environmental psychologists to explore potential avenues for improving human emotions through design interventions. However, to date, no efficient and accurate way has been established to describe these relationships. Inspired by Russell’s model of emotion, this study aims to develop an efficient process that uses coordinate mapping and can intuitively describe the impact of visual-aural perceptive attributes on human emotions. Taking typical urban green spaces (UGSs) in Chengdu as examples, this study first measured the visual and aural characteristics of study sites perceived by people and their emotional responses. The study then established the use of emotional status on a coordinate axis, allowing each visual-aural attribute corresponding to each emotional response to be projected onto the coordinates. Results suggested that the dataset composed of 279 evaluations could be classified into three distinct types of visual-aural settings and the distribution of emotions is evidently varied in different settings. It was found that aesthetic and order of visual aspects as well as eventful and harmonious soundscape in environments are more likely to make people feel pleasure, while openness and layering of the visual landscape can easily arouse people’s positive status. The research outcome broadens the practical path of soundscape research, centring on human emotions, experiences and feelings, such as the pleasantness and arousal raised in Russell’s theory of emotion. The study also makes an empirical contribution to the design of UGSs based on multi-sensory perception and serves the purpose of improving people’s environmental experiences.

Ship dimensions are an important component of static AIS information, and are a key factor in identifying the risks of ship collisions. We describe a method of extracting and correcting ship contour information using inland waterway surveillance video combined with AIS information that does not depend on ship dimension data. A lightweight object detection model was used to determine the ship's position in an image. Dynamic AIS information was included to produce multigroup control points, solve the optimal homography matrix, and create a transformation model to map image coordinates onto water surface coordinates. A semantic segmentation DeepLabV3+ model was used to determine ship contours from the images, and the actual dimensions of the ship contours were calculated using homography matrix transformation. The mAP of the proposed object detection model and the MIoU of the semantic segmentation model were 86.73% and 91.07%, respectively. The calculation error of the ship length and width were 5.8% and 7.4%, respectively. These statistics indicate that the proposed method rapidly and accurately detected target ships in images, and that the model estimated ship dimensions within a reasonable range. [ABSTRACT FROM AUTHOR]

To simulate a warp-knitted product with a specific shape, a mesh-based model for modeling and simulation is proposed. The three-dimensional geometry of the final fabric is represented as a set of polygons, each of them containing information about the 3D orientation of the yarns in the warp knitted structure. Using spatial mapping, stitch coordinates are transformed from the flat mesh model to the three-dimensional mesh model and the final rendering is accomplished. The method provides yarn level data for the complete structure and can be used for speeding up the design process of clothing with warp-knitted products. Several challenges with the larger data amount and possible ways for their solutions are discussed.

Ship dimensions are an important component of static AIS information, and are a key factor in identifying the risks of ship collisions. We describe a method of extracting and correcting ship contour information using inland waterway surveillance video combined with AIS information that does not depend on ship dimension data. A lightweight object detection model was used to determine the ship’s position in an image. Dynamic AIS information was included to produce multigroup control points, solve the optimal homography matrix, and create a transformation model to map image coordinates onto water surface coordinates. A semantic segmentation DeepLabV3+ model was used to determine ship contours from the images, and the actual dimensions of the ship contours were calculated using homography matrix transformation. The mAP of the proposed object detection model and the MIoU of the semantic segmentation model were 86.73% and 91.07%, respectively. The calculation error of the ship length and width were 5.8% and 7.4%, respectively. These statistics indicate that the proposed method rapidly and accurately detected target ships in images, and that the model estimated ship dimensions within a reasonable range.

Acousto-optical tunable filter (AOTF) does not conform to the pinhole model due to the acousto-optic interaction. A calculation method of AOTF aberrations under the condition of incident light with a large arbitrary angle is proposed to solve the problem of coordinate mapping between object space and image space of the AOTF system without refractive index approximation. This approach can provide accurate pointing information of the interested targets for the tracking and searching system based on AOTF. In addition, the effect of cut angle values of the paratellurite crystal on aberrations was analyzed to optimize the design of AOTF cutting according to different application requirements. Finally, distribution characteristics and quantitative calculation results of AOTF aberrations were verified by experiments with different targets, respectively. The experimental results are in good agreement with the simulations. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to create a new computer-aided design method based on layered stitches that can be used in the geometric structure simulation of various axial weft-knitted fabrics, including flat and cylindrical structures. Based on the analysis of structural characteristics, fabric mesh models were constructed. Layered loop spatial geometry models were established and a method of layered transparent graphic mapping was developed to represent fabrics. Structures were stratified according to the stitch graphic units, and coordinates in the fabric coordinate system were calculated by establishing the loop translation matrix and the rotation matrix. By comparing the simulation effect and time of different layers, yarn counts and fabric sizes, the simulation results showed that the simulation efficiency was affected by layers and sizes. This approach realized the three-dimensional structural simulation of flat and cylindrical axial weft-knitted fabrics with multiple layers distinctly, which reveals the intermesh relationship between different layers and provides a modeling basis for the production, processing and even performance research of industrial axial fabrics. [ABSTRACT FROM AUTHOR]

Lane detection is a significant technology for autonomous driving. In recent years, a number of lane detection methods have been proposed. However, the performance of fast and slim methods is not satisfactory in sophisticated scenarios and some robust methods are not fast enough. Consequently, we proposed a fast and robust lane detection method by combining a semantic segmentation network and an optical flow estimation network. Specifically, the whole research was divided into three parts: lane segmentation, lane discrimination, and mapping. In terms of lane segmentation, a robust semantic segmentation network was proposed to segment key frames and a fast and slim optical flow estimation network was used to track non-key frames. In the second part, density-based spatial clustering of applications with noise (DBSCAN) was adopted to discriminate lanes. Ultimately, we proposed a mapping method to map lane pixels from pixel coordinate system to camera coordinate system and fit lane curves in the camera coordinate system that are able to provide feedback for autonomous driving. Experimental results verified that the proposed method can speed up robust semantic segmentation network by three times at most and the accuracy fell 2% at most. In the best of circumstances, the result of the lane curve verified that the feedback error was 3%.

To allow mobile robots to visually observe the temperature of equipment in complex industrial environments and work on temperature anomalies in time, it is necessary to accurately find the coordinates of temperature anomalies and obtain information on the surrounding obstacles. This paper proposes a visual saliency detection method for hypertemperature in three-dimensional space through dual-source images. The key novelty of this method is that it can achieve accurate salient object detection without relying on high-performance hardware equipment. First, the redundant point clouds are removed through adaptive sampling to reduce the computational memory. Second, the original images are merged with infrared images and the dense point clouds are surface-mapped to visually display the temperature of the reconstructed surface and use infrared imaging characteristics to detect the plane coordinates of temperature anomalies. Finally, transformation mapping is coordinated according to the pose relationship to obtain the spatial position. Experimental results show that this method not only displays the temperature of the device directly but also accurately obtains the spatial coordinates of the heat source without relying on a high-performance computing platform.

This study addresses control-oriented modeling and control design of tensegrity-membrane systems. Lagrange's method is used to develop a control-oriented model for a generic system. The equations of motion are expressed as a set of differential-algebraic equations (DAEs). For control design, the DAEs are converted into second-order ordinary differential equations (ODEs) based on coordinate partitioning and coordinate mapping. Because the number of inputs is less than the number of state variables, the system belongs to the class of underactuated nonlinear systems. A nonlinear adaptive controller based on the collocated partial feedback linearization (PFL) technique is designed for system deployment. The stability of the closed-loop system for the actuated coordinates is studied using the Lyapunov stability theory. Because of system complexity, numerical tests are used to conduct stability analysis for the dynamics of the underactuated coordinates, which represents the system's zero dynamics. For the tensegrity-membrane systems studied in this work, analytical proof of zero dynamics stability remains an open theoretical problem. An H∞ controller is implemented for rapid stabilization of the system at the final deployed configuration. Simulations are conducted to test the performance of the two controllers. The simulation results are presented and discussed in detail. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper focuses on analytical methods of a finite-element method (FEM)-based edge heating system. The edge heating system plays a role in maintaining the temperature in the hot rolling process of carbon steel. Carbon steel moves along the production line and maintains the temperature by the edge heating system in the process. Power-of-the-edge heating system is transmitted to carbon steel during the process. Eddy currents are generated in carbon steel by Faraday’s law of electromagnetic induction, and eddy current loss serves as a heat source to increase the temperature. Thus, there is a need for accurate electromagnetic-field analysis and thermal analysis because the eddy current path generated in carbon steel greatly affects the heat distribution in carbon steel. This multiphysics analysis requires high reliability. Accordingly, this paper presents a coupling analysis method using an FEM-based coordinate mapping method as a more accurate analytical method. This paper also established an analytical approach to the edge heating system using the ductility analytical method of this coordinate mapping method. [ABSTRACT FROM AUTHOR]

This paper proposed a new image deformation calculative method, which was suited to both triangle and quadrilateral topology structures. The similar mapping principle in the geometric space was found between the triangle coordinates and quadrilateral coordinates by geometric method. Based on the intuitive geometric definition, the mapping reduced the quadrilateral coordinates solutions' space from 3-dimension in BC to 2-dimension. Besides, the method realized image non-linear deformation by combining the solutions with spline interpolation or physical models to construct the deformation space. Experiments show that this method has the advantages of intuitiveness and convenience when fulfiiling the image's linear and non-linear deformation and is an efficient way for image deformation. [ABSTRACT FROM AUTHOR]

Abstract: Matrix iterative algorithm LSQR is proposed for solving the linearly constrained matrix least squares (LS) problem. With the special properties of constraint matrix, Kronecker product and the coordinate mapping from the constrained space to its (independent) parameter space, we transform the constrained matrix LS problem to the unconstrained long vector least squares problem and rewrite the corresponding vector-form algorithm back to the matrix one. The resulting matrix-form iteration only consists of matrix–matrix product and does not involve the Kronecker product. Numerical results are reported to show the feasibility of the proposed method. [Copyright &y& Elsevier]

This paper describes a novel visual information concealment technique, referred to as optical watermarking, for the authentication of original printed documents. An optical watermark is a two-dimensional binary image. It can be of any shape and can be printed on any part of a document. The hidden information is embedded using phase modulation. Based on properties of the human visual system and modulation principle, the hidden information becomes visible to the human eyes only when a right "key" is positioned on top of the optical watermark with the right alignment. Here, "keys" play the similar role as keys in encryption, that is, to decode hidden information. Thus, with such a "lock and key" approach, it greatly improves the security level of the optical watermark. Due to its high security and tight link with electronic document systems, which requires documents to be finally printed on paper, the optical watermark has been applied to various electronic document systems. These are online ticketing, online bill of lading, and remote signing and printing of documents, where critical and unique information are embedded in watermarks and printed together with individual documents for future authentication. It has also been used in offline and traditional anti forgery applications, such as brand protection, preprinted high-value tickets, and identification documents. [ABSTRACT FROM AUTHOR]

The analysis and design of lightweight plate structures require efficient computational tools, because exact analytical solutions for vibrating plates are currently known only for some standard shapes in conjunction with a few basic boundary conditions. This paper deals with vibration analysis of Kirchhoff plates of general shape with non-standard boundary conditions, adopting a Rayleigh-Ritz approach. Three different coordinate mappings are considered, using different kinds of functions: 1) trigonometric and polynomial interpolation functions for mapping the shape of the plate, 2) trigonometric and polynomial interpolation functions for mapping a constraint domain of general shape, 3) products of linearly independent eigenfunctions evaluated from a standard beam in flexural vibration for describing the transverse displacement field of the plate. Flexural free vibration analysis of different shaped plates is then performed using the same approach: skew, trapezoid and triangular plates, plates with parabolic curved edges, sectors of circular plates, circular and elliptic annular plates. Purely elastic plates are considered, but the method may also be applied to the analysis of viscoelastic plates. The results are compared with those available in the literature and using standard finite element analysis. [ABSTRACT FROM PUBLISHER]

Abstract: Recent research on small amplitude helical pipes for use as bypass grafts and arterio-venous shunts, suggests that mixing may help prevent occlusion by thrombosis. It is proposed here that joining together two helical geometries, of different helical radii, will enhance mixing, with only a small increase in pressure loss. To determine the velocity field, a coordinate transformation of the Navier–Stokes equations is used, which is then solved using a 2-D high-order mesh combined with a Fourier decomposition in the periodic direction. The results show that the velocity fields in each component geometry differ strongly from the corresponding solution for a single helical geometry. The results suggest that, although the mixing behaviour will be weaker than an idealised prediction indicates, it will be improved from that generated in a single helical geometry. [Copyright &y& Elsevier]

Abstract: We have developed a three-dimensional (3D) spectral hydrodynamic code to study vortex dynamics in rotating, shearing, stratified systems (e.g., the atmosphere of gas giant planets, protoplanetary disks around newly forming protostars). The time-independent background state is stably stratified in the vertical direction and has a unidirectional linear shear flow aligned with one horizontal axis. Superposed on this background state is an unsteady, subsonic flow that is evolved with the Euler equations subject to the anelastic approximation to filter acoustic phenomena. A Fourier–Fourier basis in a set of quasi-Lagrangian coordinates that advect with the background shear is used for spectral expansions in the two horizontal directions. For the vertical direction, two different sets of basis functions have been implemented: (1) Chebyshev polynomials on a truncated, finite domain, and (2) rational Chebyshev functions on an infinite domain. Use of this latter set is equivalent to transforming the infinite domain to a finite one with a cotangent mapping, and using cosine and sine expansions in the mapped coordinate. The nonlinear advection terms are time-integrated explicitly, the pressure/enthalpy terms are integrated semi-implicitly, and the Coriolis force and buoyancy terms are treated semi-analytically. We show that internal gravity waves can be damped by adding new terms to the Euler equations. The code exhibits excellent parallel performance with the message passing interface (MPI). As a demonstration of the code, we simulate the merger of two 3D vortices in the midplane of a protoplanetary disk. [Copyright &y& Elsevier]

Lane detection is a significant technology for autonomous driving. In recent years, a number of lane detection methods have been proposed. However, the performance of fast and slim methods is not satisfactory in sophisticated scenarios and some robust methods are not fast enough. Consequently, we proposed a fast and robust lane detection method by combining a semantic segmentation network and an optical flow estimation network. Specifically, the whole research was divided into three parts: lane segmentation, lane discrimination, and mapping. In terms of lane segmentation, a robust semantic segmentation network was proposed to segment key frames and a fast and slim optical flow estimation network was used to track non-key frames. In the second part, density-based spatial clustering of applications with noise (DBSCAN) was adopted to discriminate lanes. Ultimately, we proposed a mapping method to map lane pixels from pixel coordinate system to camera coordinate system and fit lane curves in the camera coordinate system that are able to provide feedback for autonomous driving. Experimental results verified that the proposed method can speed up robust semantic segmentation network by three times at most and the accuracy fell 2% at most. In the best of circumstances, the result of the lane curve verified that the feedback error was 3%. [ABSTRACT FROM AUTHOR]

To allow mobile robots to visually observe the temperature of equipment in complex industrial environments and work on temperature anomalies in time, it is necessary to accurately find the coordinates of temperature anomalies and obtain information on the surrounding obstacles. This paper proposes a visual saliency detection method for hypertemperature in three-dimensional space through dual-source images. The key novelty of this method is that it can achieve accurate salient object detection without relying on high-performance hardware equipment. First, the redundant point clouds are removed through adaptive sampling to reduce the computational memory. Second, the original images are merged with infrared images and the dense point clouds are surface-mapped to visually display the temperature of the reconstructed surface and use infrared imaging characteristics to detect the plane coordinates of temperature anomalies. Finally, transformation mapping is coordinated according to the pose relationship to obtain the spatial position. Experimental results show that this method not only displays the temperature of the device directly but also accurately obtains the spatial coordinates of the heat source without relying on a high-performance computing platform. [ABSTRACT FROM AUTHOR]