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From a consideration of the properties near the edge of a flat finite-thickness strip and an elliptic cross-section strip, it is shown that the divergence that arises in the perturbation method near a sharp edge can be handled by halting the loss calculation at a definite distance just short of the strip edge. This distance can be expressed in terms of the radius of curvature at the tip for a rounded edge, and in terms of the strip thickness for a flat edge.

This paper presents fundamental results about how zero-curvature (paper) surfaces behave near creases and apices of cones. These entities are natural generalizations of the edges and vertices of piecewise-planar surfaces. Consequently, paper surfaces may furnish a richer and yet still tractable class of surfaces for computer-aided design and computer graphics applications than do polyhedral surfaces.

Exact transverse electric and magnetic mode solutions of four triangular cross-section waveguides have been found via a new general method using Snell's law and superposition of plane waves. This paper presents results for 1) equilateral, 2) 30°, 30°, 120°, 3) isosceles right, and 4) 30°, 60° right triangular waveguides. The electric and magnetic field solutions form finite sums of separable rectangular harmonics and are the only waveguides of triangular cross section for which such solutions have been found.

This paper presents a method of determining the characteristic impedance of an ellipse arbitrarily located between parallel conducting planes when the region between the planes is filled with two different dielectric media. The same generalized formulation is then extended to the case when one of the ground planes is moved to infinity. The impedance data for various locations of the dielectric interface with respect to the conductor of elliptic and circular cross sections are presented. The results of some of the special cases are compared with those available in the literature.

A formulation is proposed to calculate the frequencies of the eigenmodes for a resonator with a thin conductor disk placed in the median plane between two infinite parallel conductor plates. The numerical analysis is carried out for the E- and EH-modes, and these eigenvalues are calculated as the function of the ratio of the disk radius to the distance between the disk and one of the infinite conductor plates. It is shown that at a ratio greater than a certain value the exact eigenvalue is smaller than the one predicted by applying the conventional method for two-dimensional bifurcation of rectangular waveguide, but the latter becomes closer to the exact one with increasing ratio. The availability of our exact eigenvalues is demonstrated in determining experimentally the dielectric constant of Teflon plate specimen by applying those values. Then the constancy of the measured dielectric constant is confirmed irrespective of the modes and the ratios.

New quasi-static models for the computer-aided design (CAD) and analysis of open suspended and inverted microstrip lines are reported. The models are obtained through generalizing those reported earlier and are applicable up to epsilon/sub r/= 20, thereby covering all the practically used substrate materials for these structures. The models also cover a larger range of dimension ratios and are accurate to within 0.6 percent for analysis and within 1 percent for synthesis.

The complex potential function W = A (In z + C /sub n/z/sup n/) generates a zero-potential line approximating a regular polygon of N sides very closely, except in the nearly field-free region. By means of this function we work out the characteristic impedance, the power-carrying capacity, and the attenuation constant of the polygonal line of N sides wtth a round inner coaxial conductor in a closed form of elementary functions with good accuracy compared to more complex solutions. Results for N = 3 are believed to he nearly as good as those available in the literature.

It is well known that the fringing capacitances determined for rectangular bars between parallel plates interact with each other when w/(b -t)/spl rarr/0. The limit of this interaction as s/spl rarr/0 for fixed w, b, and t is determined for symmetrical odd-mode fringing capacitances. This limit, together with an exact value known from one rectangular section and the known asymptotic value as s/spl rarr/ 0, permits one to estimate the values for all s. The same is true for the interaction of the symmetrical even-mode fringing capacitances, except that their interaction is readily shown to tend to zero as s/spl rarr/0.

This paper gives a simple method for the determination of the characteristic impedance of an inner regular polygon concentric with an outer circle. The approach makes use of the method of superposition for plane sheets of charge which were radially disposed in the polygon. The results are in good agreemnt with those obtained by Laura and Luisoni.

In the evaluation of "fringing capacitances" one is required to map the specified geometry in the z plane onto the upper half t plane and then to determine the limiting value of the capacitance between the two segments of the real axis---corresponding to the two conductors in the z plane---when one or both of the gaps between them approaches zero. The usual procedure of mapping the upper half t plane onto an infinite parallel plate configuration, which is often more involved than the first mapping, can be eliminated if one recognizes that the capacitance obtained by mapping the upper half t plane onto a rectangle by means of a well-known elliptic function exceeds, in the limit, the correct value by (log 2)//spl pi/, for each gap involved.

A majority of textbooks on antennas neglect to show the use of the dispersion diagram in explaining the properties of a helical antenna. This short paper shows that the region of operation of an axial-mode helical antenna can be easily located on the dispersion diagram. The close relationship between the dispersion diagram as evaluated by Klock and the theory of operation of the helical antenna given earlier by Kraus is also demonstrated.

There is an urgent need to efficiently compress Light Detection and Ranging (LiDAR) point cloud geometries. However, few studies consider geometry inter-prediction for exploiting temporal correlations between different LiDAR point cloud frames. In this paper, we investigate two fundamental problems of geometry inter-prediction: motion estimation (ME) and coding structure under the inter-exploration model of geometry-based point cloud compression (G-PCC). Under the inter-exploration model of G-PCC, the key to a good ME algorithm is to design an accurate criterion for estimating the bit cost of an octree node. In the previous work, a logarithmic relationship between the prediction distortion and the bit cost was used as the criterion. We first note that the multiscale binary prediction residue, instead of the prediction distortion, is the key factor in determining the bit cost. Then, a linear relationship between the number of 1s and 0s in the multiscale binary prediction residue and the bit cost is built and used as the ME criterion. In terms of the coding structure, only the IPPP coding structure is investigated in all previous geometry inter-prediction algorithms. The use of the hierarchical coding structure is first investigated in this paper. We further propose determining the use of the IPPP or hierarchical coding structure at the group of pictures (GoP)-level based on rate distortion optimization to improve the performance. The proposed algorithms are implemented in the inter-exploration model of G-PCC. The experimental results show that compared with the inter-exploration model of G-PCC, the proposed algorithms can provide an average of 2.1% bitrate savings.

Vehicle-to-vehicle (V2V) wireless communications have many envisioned applications for ensuring traffic safety and for addressing traffic congestion. However, developing suitable communication systems and standards for this purpose requires developers to have accurate models for the V2V propagation channel. Likewise, the dynamic evolution of multipath components (MPCs) in V2V channels has not been well modeled in existing models. In this paper, we propose a geometry-based stochastic channel model for a lightly built-up urban environment and then parametrize the model from measurements. The MPCs are extracted based on a high-resolution parameter estimation; they are tracked and clustered through a joint algorithm. The identified clusters are classified as line-of-sight, reflections from static scatterers, reflections from mobile scatterers, multiple-bounce reflections, and diffuse scattering. Specifically, the multiple-bounce reflections are modeled as twin clusters that follow the COST 273/COST2100 approach. The paper gives a full parameterization of the channel model and supplies a step-by-step implementation recipe. We verify the model by comparing two second-order statistics, i.e., the root-mean-square (RMS) delay spread and the angular spreads of arrival/departure derived from the channel model, to the results obtained directly from the measurements. Furthermore, we also identify several key factors that strongly impact the synthetic channel performance.

This paper presents a novel strategy to simultaneously estimate the direction of arrival (DOA) of a source signal and the phase error of a partly calibrated array with arbitrary geometry. We add up the snapshot data of two different sensors, and then extract a knowledge associated with the DOA and phase errors of these two elements by using singular value decomposition. In such a manner, we can establish a series of linear equations with respect to the unknown DOA and phase error, by simply conducting the procedure on any two sensor elements. On this basis, it can be shown that the problem of jointly estimating DOA and phase error is equivalent to a least square (LS) problem with a quadratic equality constraint. To solve this LS problem (so that the DOA and phase error can be obtained), an effective convex–concave procedure is employed. Different from the conventional algorithms that are limited to specific array geometries, the proposed one is suitable for arrays with arbitrary geometries. More importantly, the devised method only requires one extra calibrated sensor, which is not necessarily adjacently located with the reference one. Several simulations are carried out in this paper and the effectiveness of the devised method can be clearly observed.

A new approach for extracting the hairiness from fabric based on the predicted fabric surface plane is presented in this paper to extract the hairiness from the depth image. The depth from focus (DFF) technique is utilized in this study to establish the depth image of the pilled fabrics by using a series of image layers captured under a microscope. A pilled fabric depth image provides information on the hairiness and the fabric surface, and the hairiness is located above the fabric surface. However, the depth value of the fabric surface covered with hairiness cannot be directly obtained. Therefore, for hairiness extraction, a predicted plane of the fabric surface is fitted by selecting several base points on the fabric surface. The target above the predicted plane will be considered as hairiness and will be extracted. The oversegmentation method based on the mean shift algorithm is used in the study to select the base points of the fabric surface. First, several seed points are marked along the Sobel edges; then, several oversegmented areas are formed after the growth of the seed points, which are called split pieces in this paper. The split pieces of the fabric surfaces are selected as the base points according to the depth value as well as the spatial direction of each split piece. Finally, the predicted plane of the fabric surface is established using these base points. The results of significance testing show that is it reasonable to assume that the fabric surface can be expressed as a plane. The results of the residual examination show that the predicted plane can correctly calculate the depth value (z) of the fabric surface at any plane position (x, y). The extracted hairiness images show that hairiness can be correctly and completely obtained through the predicted plane.

Soil Moisture and Ocean Salinity (SMOS) mission has successfully contributed to global soil moisture products since 2009. Validation and calibration activities were conducted worldwide, yet some of the validation results do not fulfill the targeted accuracy of ±0.04 $\text{m}^{3}\text{m}^{-3}$ . This paper presented the site-specific calibration of the V620 retrieval algorithm with in situ data collected at selected agricultural sites in the humid tropical regions, Malaysia. This set of data has been validated where low accuracy of SMOS soil moisture products was found. To improve the SMOS soil moisture retrieval, calibration of SMOS soil moisture retrieval algorithm based on the L-band Microwave Emission and Biosphere model and SMOS Level 1C $\text{T}_{\mathrm {B}}$ products, considering the local parameters was conducted. The calibration proves that these site-specific parameters improve the product’s accuracy. Validation of SMOS Level 2 product with in situ data showed bias, root-mean-square error (RMSE), and unbiased RMSE (ubRMSE) ranging from 0.050 to 0.118 $\text{m}^{3}\text{m}^{-3}$ , 0.068 to 0.142 $\text{m}^{3}\text{m}^{-3}$ , and 0.069 to 0.103 $\text{m}^{3}\text{m}^{-3}$ , respectively. The soil moisture retrieval based on the calibrated model showed an improved bias of 0.020–0.056 $\text{m}^{3}\text {m}^{-3}$ and RMSE of 0.026–0.065 $\text{m}^{3}\text{m}^{-3}$ . The ubRMSE ranges from 0.017 to 0.034 $\text{m}^{3}\text{m}^{-3}$ . Recently released SMOS-IC V105 product was also validated, where small improvements were noticed when compared to the accuracy of SMOS Level 2. This paper shows the importance of local parameters in retrieving soil moisture with higher accuracy compared to the use of global generalized parameters that are used in the original SMOS soil moisture retrieval algorithm.

This paper evaluates the capability of Sentinel-1 VH-polarized synthetic aperture radar signals, involving 738 scenes in the interferometric wide swath (IW) mode, for ocean surface wind speed retrieval using a novel subswath-based C-band cross-polarized ocean model. When compared with in situ measurements, it is observed that wind speed retrieval accuracy varies progressively along swath, with the most accurate wind speed retrievals being derived from subswath 3 [root-mean-square error (RMSE) of $1.82\,\,\text {m}\cdot \mathrm {s}^{-1}$ ], followed by subswath 2 (RMSE of $1.92\,\,\text {m}\cdot \mathrm {s}^{-1}$ ), while subswath 1 showed the lowest retrieval accuracy (RMSE of $2.37\,\,\text {m}\,\cdot \,\mathrm {s}^{-1}$ ). The average RMSE of wind speeds retrieved from all the three subswaths is $2.08\,\,\text {m}\,\cdot \,\mathrm {s}^{-1}$ under low-to-high wind speed regimes (wind speeds $ ). We further observed that the dependence of VH-polarized normalized radar cross section (NRCS) on incidence angle is attributable to the high and changing noise equivalent sigma zero (NESZ) with incidence angle under low-to-moderate wind speed regimes. And that strong VH-polarized radar signals could overcome the NESZ effect, thereby eliminating the dependence of VH-polarized NRCS on incidence angle under strong wind conditions. For Sentinel-1 IW mode VH-polarized data, the effect of NESZ could be ignored when wind speeds are greater than $15\,\,\text {m}\cdot \mathrm {s}^{-1}$ , as a better wind speed retrieval performance of these data has been recorded in this paper at wind speeds greater than $10\,\,\text {m}\cdot \mathrm {s}^{-1}$ , owing to an RMSE below $1.6\,\,\text {m}\cdot \mathrm {s}^{-1}$ and biases ranging from −0.5 to $0.5\,\,\text {m}\cdot \mathrm {s}^{-1}$ .

We studied the type of cusps on the caustic in the optical model that the coplanar point light source irradiates a singular planar curvilinear mirror in our last paper. In this paper, we give a oneto-one correspondence between the wavefront (orthotomic) and the caustic. According to this one-toone correspondence, we can derive the property of one of them from that of the other one. To prove it, we formulate the involutes of (n, m)-cusp curves and study their singular properties. Furthermore, we give a duality theorem for evolute-involute pairs. This theorem plays a crucial role in the one-to-one correspondence mentioned earlier.

This paper applies time modulation to deal with the design of dual-band antenna arrays in a circular geometry using a micro-strip-fed slot antenna as an element in the frequencies of 2.4 and 5.5 GHz. The motivation for this paper is to exploit the properties and advantages of time-modulated arrays in a dual-band scenario considering a circular geometry. This design considers the optimization of the time switched sequences of the antenna elements in the circular geometry for both operation frequencies. The design process to find the optimal switch- ON intervals of the circular array is carried out by means of the method of differential evolution and particle swarm optimization. The main contribution to the field of this paper is the dual-band performance evaluation of circular antenna arrays considering time modulation and measurements of the antenna element pattern. The performance evaluation and the results and discussion are achieved in terms of the radiation pattern with the measured antenna element, sidelobe level, sideband levels, switching times and efficiency.

International audience; Hybrid broadcast/broadband network (HBBN) presents a potential solution to mitigate the increasing demand for mobile TV. A proper HBBN deployment alleviates the limitations that each standalone network faces, thereby enhancing the global network coverage and efficiency. In this paper, we propose to address the question of performance improvement expected from such HBBN by means of an analytical framework based on stochastic geometry modeling. To this end, we introduce a generic model of the HBBN where multiple broadcast transmitters and a broadband network are deployed in the same area, jointly offering linear services, one of the mobile TV services. Two different approaches derived from stochastic geometry are applied and compared through the analysis of what is commonly referred to as a Point Hole Process (PHP) Original Poisson Point Process (PPP), and reduced PPP. Both approaches are thoroughly analyzed to give better insights into broadcast/broadband coexistence while taking into account the inter-cell interference of both networks. Exact and simplified expressions for the key performance metrics are derived such as the probability of coverage and ergodic capacity. Those expressions are then used to numerically maximize the spectral and power efficiency of the HBBN regarding the broadcast coverage radius and transmitters density. The results show that for a wide range of user density, the HBBN introduces gain compared to either BB or BC networks. To the best of the authors knowledge, this paper presents the first work dealing with the optimization of HBBN based on such a generic model and taking inter-cell and inter-network interference into consideration.

Polarization orientation angle (POA) is an important parameter of polarimetric radar scattering from slopes in mountainous region. It is known that surface tilted in azimuth direction and buildings not aligned in the along-track direction induce polarization orientation shifts. Earlier research has established orientation angle as a function of radar imaging geometry and surface slopes, and that POA estimation can be derived from polarimetric radar data using circular polarization. Besides these, polarimetric scattering from steep slopes and its relation to POA remain not well understood. In this paper, we address these issues by adopting a tilted surface model based on Bragg scattering. We have found that, as the azimuthal slope increases, $\vert $ VV $\vert $ decreases at a faster rate than $\vert $ HH $\vert $ , they become equal, when POA is ±45°, and $\vert $ HH $\vert >\vert $ VV $\vert $ afterward. In other words, the Pauli component, $\vert $ HH - VV $\vert $ reduced to zero at POA = ± 45°, and the typical Bragg scattering characteristics of $\vert $ VV $\vert >\vert $ HH $\vert $ does not apply when steep slope is present inducing $\vert $ POA $\vert > 45^{\circ }$ . Furthermore, the cross-pol $\vert $ HV $\vert $ does not always increase with azimuth slope but also reaches a maximum then decreases to zero. In addition, we investigate the effect of soil moisture on polarimetric SAR (PolSAR) scattering characteristics of steep terrain and the effect of vegetation over surface on POA estimation. The latter is demonstrated with NASA/JPL TOPSAR L-band PolSAR data and C-band InSAR data. Another significance of this paper is that it provides a direct and rigorous derivation of POA equations. The earlier version was derived from a different concept.

Displays that render colors using combinations of more than three lights are referred to as multiprimary displays. For multiprimary displays, the gamut, i.e., the range of colors that can be rendered using additive combinations of an arbitrary number of light sources (primaries) with modulated intensities, is known to be a zonotope, which is a specific type of convex polytope. Under the specific three-dimensional setting relevant for color representation and the constraint of physically meaningful nonnegative primaries, we develop a complete, cohesive, and directly usable mathematical characterization of the geometry of the multiprimary gamut zonotope that immediately identifies the surface facets, edges, and vertices and provides a parallelepiped tiling of the gamut. We relate the parallelepiped tilings of the gamut, that arise naturally in our characterization, to the flexibility in color control afforded by displays with more than four primaries, a relation that is further analyzed and completed in a Part II companion paper. We demonstrate several applications of the geometric representations we develop and highlight how the paper advances theory required for multiprimary display modeling, design, and color management and provides an integrated view of past work on on these topics. Additionally, we highlight how our work on gamut representations connects with and furthers the study of three-dimensional zonotopes in geometry.

This paper presents the numerical calculation of the relative sliding distance between the pad and the wafer in a rotary-type chemical-mechanical planarization (CMP) system. The numerical scheme developed in this paper considered most of the possible kinematical and geometrical variables. While the pad was rotating, and the wafer was rotating and sweeping, the point trajectories on the wafer were calculated by standard coordinate transformations. The effect of groove patterns on the pad surface was investigated for the relative sliding distance of the wafer. Three types of pad surface geometries, namely flat, circular-type, and rectangular-type grooves, were considered. From the simulation results, we evaluated the nonuniformity (NU) of the relative sliding distance distribution on the polished wafer surface. It was found that the groove patterns have a significant effect on the result of the CMP, as well as the width and pitch of the groove. It was found that the groove patterns increase the NU of the sliding distance distribution. The circular-type groove caused the greater NU than the rectangular-type groove under the identical operating conditions. The optimized operating conditions were varied for different types of the groove patterns. The simulation method proposed in this paper may be further extended to analyze other process variables.

Terrestrial laser scanning is a promising tool for estimating leaf angle (including leaf inclination and azimuthal angles) distribution (LAD). However, previous studies focus on the retrieval of leaf inclination angle distribution, very few studies have considered the distribution of leaf azimuthal angle due to the restriction of measurement techniques. In this paper, we developed a new method to obtain more accurate leaf inclination and azimuthal angle estimations based on leaf point cloud segmentation and filtration and then fit LAD functions using two-parameter Beta-distribution model. In addition, we constructed a new projection coefficient model with two parameters $G(\theta $ , $\varphi$ ) using Nilson’s algorithm based on the accurate retrieval of LAD. To assess the influence of leaf numbers on leaf inclination and azimuthal angle estimations, we modeled 160 individual leaves and 10 trees with different leaf numbers. In addition, to validate the final results, we also sampled three magnolia trees with different leaf numbers and manually measured leaf inclination and azimuthal angles of all their leaves using an angle measurement device. All results showed that the method proposed in this paper can provide accurate leaf inclination and azimuthal angles (leaf inclination angle: $R^{2} = 0.98$ , RMSE = 24° and leaf azimuthal angle: $R^{2} = 0.99$ , RMSE = 3.44°). The simulated LAD and $G(\theta $ , $\varphi$ ) estimations based on these leaf inclination and azimuthal angles were strongly correlated with those obtained from ground truth measurements ( $P >0.05$ ).

In this paper, we investigated the plasmon coupling, quantum yield (QY) and effect of tip geometry of gold nanoparticles (AuNPs) using finite-difference time-domain (FDTD) simulation. Standalone AuNPs spectra have been obtained using the most reliable electromagnetic theory such as Mie theory for spherical nanoparticle such as gold nanosphere (AuNS) and Mie-Gans theory for ellipsoidal AuNPs such as gold nanorod (AuNR). We reported the scattering cross section for standalone and coupling particle using the modified dielectric constant, where the size effect of small particles and the retardation effect of large particles have been taken into consideration for both the analytical calculation and FDTD simulation. Plasmon coupling effect of AuNS dimer of 80-nm diameter and AuNR dimer (side-by-side geometry) of aspect ratio 3.8 has been investigated using FDTD simulation. We also quantified the QY in terms of cluster to monomer ratio for AuNS and AuNR, which is analogous to the ratio of acceptor and donor chromophore in biological systems. The QY of monomer, dimer, and trimer of 40-nm diameter AuNS has been perceived using FDTD simulation, integrating the whole spectrum over 400-1000 nm wavelength regime. Additionally, effect of tip geometry of AuNPs has been investigated and significant field enhancement due to the variation in shapes such as AuNS, AuNR, gold dumbbell, and gold bipyramid has also been reported. The novelty of the paper lies in the presentation of a systematic study of the plasmon coupling of different sizes and shapes of AuNP, quantification of the QY, and probing the effect of tip geometry for a single material such as AuNP using the FDTD simulation. Moreover, we believe that our in-depth analysis of AuNP laid the foundation to determine the scattering cross-section, QY, and near-field enhancement for more complex structures and geometries of other novel materials. Conclusively, the investigation results demonstrate that plasmonic nanoparticle can be used as a molecular probe for bioimaging, sensing, cell signaling, and biological therapeutic intervention.

This paper presents a geometry-based stochastic channel model (GSCM) for a 3GPP millimeter-wave (mmWave) high-speed train (HST) scenario. An important demand of the mmWave HST channel model is the spatial consistency during movement. In order to meet this requirement, the environment pattern containing the most effective geometry information is proposed, which is useful for generating an integral and accurate channel geometry. Since the measurement of a mmWave channel is deficient for high mobility, the proposed channel model is developed using a ray-tracing (RT) simulator that is validated with the channel measurements performed in the HST scenario at 93.2 GHz. The paper gives a full parameterization for the proposed model and its implementation for channel simulation. The verification is made through a comparison of the proposed model and the measurement-validated RT simulations in terms of the power delay profile, the Ricean $K$ -factor, and the second-order statistics for the delay and angle domains. Finally, for the design of mmWave HST communication systems, the time-varying channel characteristics are evaluated in the delay and Doppler domains.

This paper proposes a new configuration of acoustic sensors—the collocation of three cardioid sensors in perpendicular orientation, in order to increase the mainlobe-to-sidelobe height ratio (possibly to $\infty$ ). This paper will analyze such a proposed triad's “spatial matched filter” beam-pattern that is independent of the frequency/spectrum of the incident signals. Specifically, this paper will analytically derive the mainlobe's pointing error in azimuth-elevation, the mainlobe's two-dimensional beam “width,” the necessary and sufficient conditions for a sidelobe to exist, the mainlobe-to-sidelobe height ratio, and the array gain. These above characteristics depend on the cardioids’ “cardiodicity parameter” and on the beam's nominal “look direction.”

Working with prescribed velocity gradients is a promising approach to efficiently and robustly simulate highly viscous SPH fluids. Such approaches allow to explicitly and independently process shear rate, spin, and expansion rate. This can be used to, e.g., avoid interferences between pressure and viscosity solvers. Another interesting aspect is the possibility to explicitly process the vorticity, e.g., to preserve the vorticity. In this context, this paper proposes a novel variant of the prescribed-gradient idea that handles vorticity in a physically motivated way. In contrast to a less appropriate vorticity preservation that has been used in a previous approach, vorticity is diffused. The paper illustrates the utility of the vorticity diffusion. Therefore, comparisons of the proposed vorticity diffusion with vorticity preservation and additionally with vorticity damping are presented. The paper further discusses the relation between prescribed velocity gradients and prescribed velocity Laplacians which improves the intuition behind the prescribed-gradient method for highly viscous SPH fluids. Finally, the paper discusses the relation of the proposed method to a physically correct implicit viscosity formulation.

This paper aims to develop a high-precision detection approach for catenary geometry parameters of electrical railway based on vision technology. The novel idea of the proposed detection method is that, the image coordinates of the spot formed on the contact line by a laser emitter are mapped to the world system to obtain the conductor height and stagger. In the proposed detection system, the key factors that affect the detection accuracy include two components, the localization of the spot and the correction of the detection value. To solve these problems, the genetic particle filter algorithm based on particle swarm optimization (PSO-GAPF) is presented to track and locate the spot in the image. Compared with the standard particle filter, PSO-GAPF can improve the particle deprivation and increase the accuracy of state estimation. In addition, Kalman filter (KF) is used for correcting the detected value of catenary geometry parameters. In this paper, first of all, the model of spot target is established according to the feature distribution of gray color histogram, and the tracking and locating of the spot in the image are realized by PSO-GAPF. Second, the detection formulas of catenary geometry parameters are deduced by utilizing the space coordinate transformation to compute the conductor height and stagger. At last, the correcting of the catenary geometry parameters is achieved by KF. The real-life detection results show that the proposed method has high precision, and can meet the requirements of real-time catenary geometry parameters detection system.

In this paper, the resonant cavity problem with anisotropic fully conducting media, complex geometrical structure and perfect electric conductor walls is investigated. We solve this problem based on the finite element method (FEM) with tangential and linear normal (CT/LN) element and standard linear element. An effective numerical method is proposed by us such that it is free of nonphysical modes. After the FEM discretization, we need to solve a quadratic algebraic eigenvalue problem with a linear constraint condition. In order to overcome this difficulty in the field of numerical algebra, we change this algebraic eigenvalue problem into a generalized eigenvalue problem by introducing an auxiliary zero eigenvector. Moreover, when the permittivity and conductivity are two constants, both the eigenmodes of infinite algebraic multiplicity and all the nonphysical modes are also removed by linearization method. Several numerical experiments show that computational method in this paper can suppress all the spurious modes.

The nonconformal domain decomposition methods (DDMs) of the hybrid finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) are presented for computing large electromagnetic scattering/radiation problems. The numerical performance of different transmission conditions between finite element method (FEM) subdomains, and FEM and BI domains is studied in this paper. The Dirichlet transmission condition (DTC) employed at the interface between FEM and BI domains has faster convergence than the Robin-type transmission condition, and this finding is different from the conclusions for the FEM DDMs published in the literature. Furthermore, the cement-element (CE)-based dual-primal finite element tearing and interconnecting (FETI-DP) DDM has faster convergence than the Lagrange-multiplier-based FETI-DP method under the FE-BI system, and is also different from that under the system of the FEM with the absorbing boundary condition (FEM-ABC). It shows that the DDMs of FE-BI-MLFMA have some essential differences from those of FEM-ABC. The analysis of these numerical phenomena is presented in this paper. Further comparison between the DDMs of FE-BI-MLFMA and FEM-ABC demonstrates that the DDMs of FE-BI-MLMFA have essential advantages over those of FEM-ABC. Various numerical experiments confirm the accuracy, efficiency, and flexibility of the nonconformal DDM of FE-BI-MLFMA, which is the CE-based FETI-DP DDM with DTC connecting FEM and BI.

In this paper, a new method for achieving absolute position information is proposed. As opposed to the common approach of matching magnetoresistive (MR) sensors to specific pole pitch patterns on medium, this paper validates the possibility of mismatching between the two with the same element spacing in MR sensors over pole pitch variation from 1.1 to 1.3 mm in two-row magnetic patterns. The first row is the incremental row, which has the same 1 mm pole pitch as the sensor. The second row serves as the absolute row with the tweaked pole pitch pattern. With different pole pitches in the two rows, an offset between each pole exists before the two different pole pitches reach their common multiple. Through analyzing Lissajous profiles resulted from both rows, it is found that the relation between two rows on each position is unique, and hence can be used as a mean to determine absolute position.

Complex scattering targets are often made by structures constituted by wedges and penetrable substrates which may interact at near field. In this paper, we describe a complete procedure to study this problem with possible developments in radar technologies (like GPR), antenna development, or electromagnetic compatibility (tips near substrates). The diffraction of an incident plane wave by a perfectly conducting (PEC) wedge over a dielectric half-space is studied using generalized Wiener–Hopf equations (GWHEs), and the solution is obtained using analytical and numerical–analytical approaches that reduce the Wiener-Hopf (WH) factorization to integral equations (IEs). The mathematical aspects are described in a unified and consistent theory for angular and layered region problems. The proposed procedure is valid for the general case and the paper focuses on E-polarization at normal incidence. The solutions are given in terms of geometrical/uniform theory of diffraction (GTD/UTD) diffraction coefficients and total far fields for engineering applications. This paper presents several numerical test cases that show the validity of the proposed method.

Due to the special principle of synthetic aperture radar (SAR), SAR images exhibit many special phenomena. This becomes more obvious on high-resolution (HR) SAR images, as much more details are contained. We firmly believe that these details are where the advantages of a SAR image lie on and they provide some key clues for building the framework to understand SAR images. It comes to our attention that many special details in SAR images are due to the mechanism of multipath (MP) scattering. Dominated by the synthetic aperture progress, MP scattering reveals many interesting properties in SAR images. In this paper, we first analyze the mechanism of MP scattering by using the ray perspective on typical structure units. The main characteristics of the MP scattering in the SAR image are presented, such as the offset, prolong, segment, and blurring. Then, the analysis is extended to typical structures with MP scattering, such as bridges, buildings, and oil tanks by using Terra-SAR images. Finally, we explore the utilization of characteristics of MP scattering on geometry extraction from HR SAR images. The results prove the validity and the precision of our analysis. Some advices are also provided on the applications of the characteristics of the MP scattering in the SAR image. It is expected that this paper is helpful for the SAR image understanding and application.

This paper proposes a design solution for static eccentricity (SE) in axial flux resolvers (AFRs). There are two definitions for SE in AFRs. The first approach is based on the definition of SE in conventional radial flux resolvers, wherein the rotor axis does not coincide with the stator bore, but the rotor rotates around its own shaft. In other words, it is different in the angular inclination of the rotor and stator axis. Thus, the air gap of the motor is not uniform. In the second approach, which is more common in AFRs, when SE occurs, air-gap length remains uniform. Rotor axis remains parallel with the stator axis, although it does not coincide with the stator bore. This means that there is radial misalignment of the rotor and stator axis. In this paper, both definitions are considered, and an innovative design solution is proposed to decrease the effect of both types of SE in the accuracy of detected position. 3-D time stepping finite-element analysis is used to show the success of proposed designs. Finally, both models were evaluated using experimental results.

This paper concerns the detection of local magnetic induction in peripheral regions of transformer cores. Induction distributions are important for the interpretation of local losses and magnetostriction. Most authors use advanced numerical modeling-like FEM for the computation of local induction values. However, effective estimations tend to be impossible due to non-linearity, extreme anisotropy, and complex effects of hysteresis. As an alternative to FEM, the conventional method for local measurements is to use arrays of single-turn search coils. However, this method is laborious, and it affects the measured values in strong ways due to the thickness of the arranged wires and artifacts from the drilled holes. This paper presents a novel approach for peripheral core regions based on measurements with a tangential induction coil, i.e., a field coil with a ferromagnetic core. The sensor was tested on a model transformer core stacked from three packages of different widths of grain-oriented electrical steel, for the nominal induction of 1.7 T. As an advantageous effect, the sensor does not cause any interlaminar air gaps and detects the amplitude of the induction not only in planar, but also in lateral positions. Results from $\boldsymbol {\sim }100$ measuring positions are presented. They show that the induction distribution is inhomogeneous with variations up to $\boldsymbol {\sim }15$ %. High induction values were measured in the widest main package of the core, in contrast to much lower ones in the outer packages. On the other hand, the corners, yokes, and T-joints show much more uniformly flux distribution. The findings of this paper can be assumed to be relevant for industry in order to optimize the construction of cores for the purpose of their uniform utilization.

Nowadays FinFETs integrated into complex circuit applications can fulfill the demand of smartphones and tablets for better performance and make chips that can compute faster. This paper studies the impact of $H_{{\rm Fin}}$ and $W_{{\rm Fin}}$ variations on various performance matrices including static as well as dynamic figures of merit (FOMs). With the help of aspect ratio ( $W_{{\rm Fin}}/H_{{\rm Fin}}$ ), the device is branched into three parts, i.e., FinFET, Trigate, and Planar MOSFET. This unique report is a presentation of a detailed analysis about the impact of fin height ( $H_{{\rm Fin}}$ ) and width ( $W_{{\rm Fin}}$ ) on various performances including the dc as well as ac FOMs. The static or low-frequency performances like threshold voltage ( $V_{{\rm th}}$ ), on current ( $I_{{\rm on}}$ ), off current ( $I_{{\rm off}}$ ), power dissipation, transconductance ( $g_{{\rm m}}$ ), output conductance ( $g_{{\rm d}}$ ), transconductance generation factor ( $TGF = g_{{\rm m}}/I_{{\rm D}}$ ), early voltage ( $V_{{\rm EA}}$ ), gain ( $A_{{\rm V}}$ ), and dynamic or high-frequency performances as gate capacitance ( $C_{{\rm gg}}$ ), cutoff frequency ( $f_{{\rm T}}$ ), output resistance ( $R_{{\rm 0}}$ ), intrinsic delay are systematically presented with the variation of device geometry parameters. The results presented in this paper can be of great help to device engineers in designing 3-D devices as per their requirement.

High-frequency copper losses, or copper losses produced during switching in switching-mode power supplies, are very much related to variations of the magnetic field distribution within the core window. When operating at high frequency, the current flowing through the windings of a magnetic component experiences redistribution across the section of the conductor due to skin and proximity effects. Current redistribution depends not only on actual frequency, but also on conductor size and layer distribution. While previous works aim to optimize windings size by considering just the current flowing through that winding, this paper shows that, in most of the cases, current redistribution is strongly affected by the currents at the other transformer windings, which should also be taken into account. This paper derives a mathematical expression to calculate the evolution, in the time domain, of the magnetic field during the switching, which will be later used to obtain the current density distribution and copper losses in the component. An easy-to-calculate expression will be derived that allows magnetic windings to be analyzed and/or optimized, because losses are expressed as a function of the winding geometry and position. An application example is also included. All the equations derived are verified by comparing them with the results obtained from a differential equations solver, and with previous works when applicable. Experimental results are also provided.

This paper presents a methodology for generating geometries for interior permanent magnet (IPM) motors in electric vehicles (EVs) through the application of artificial intelligence (AI) and image processing (IP) techniques. Due to the implementation of green agreements and policies aimed at reducing greenhouse gas emissions, EVs have become popularity. As a consequence, the improvement studies on the powertrain and battery system of EVs are focused. Especially for the powertrain, design optimization studies of e-motor have increased in the literature. One of the most widely used e-motor topologies is interior permanent magnet (IPM) motor. However, designing the IPM motor presents a challenge due to the dynamic considerations with geometric constraints. Therefore, e-motor designers encounter challenges related to determining initial geometry and the long time of the optimization process. To address these challenges, a novel approach is proposed that leverages machine learning (ML) techniques in combination with IP to generate initial geometries and design parameters for IPM motors. The proposed approach generates images of the motor geometry and extract dimensional features from the resulting images by using artificial neural networks (ANNs). The proposed method performs an analysis of the input vectors to reduce their size using techniques such as Histogram, 2D Maximum, 2D Mean, 2D Minimum, 2D Standard Deviation, and 2D Variance to enhance feature extraction. Additionally, FFT (Fast Fourier Transform) and IFFT (Inverse Fast Fourier Transform) are used to improve the neural network process in generating the image geometry. Further, the generated image geometry is improved by applying digital filtering techniques such as Log, FFT, Log+FFT, Laplacian, Sobel, and Histogram Equalization. Finally, the trained ANNs are tested to validate the results by using Ansys RMXprt and Maxwell. Eventually, the proposed method represents an innovative solution to generating initial geometries for IPM motors in EVs that satisfies desired design requirements. This approach leverages the power of AI and image processing techniques, which could lead to significant improvements in the optimization process for IPM motors, accelerate the designer’s analysis process, and enhance the performance of EVs.

The aim of this paper is to investigate the effects of overlaying dielectric layer and its local geometry on keep-out zone (KOZ) induced from through-silicon via (TSV) in 3-D integrated circuit applications. Prior to the study, the saturated current changes (or corresponding carrier mobility changes) of both nMOS and pMOS transistors from the finite element simulations are validated with experimental data. After the model verification, six cases with various local dielectric structures are proposed to minimize KOZ. The results show that the case with an embedded SiO 2 on the top of Cu TSV has the least effect on saturated current change (or the minimum KOZ) among those cases. Furthermore, the various embedded-SiO 2 depths on the top of Cu TSV are further investigated. It is found that saturated current change of pMOS placed in both horizontal and vertical directions on Si substrate can be minimized using a 6-μm-deep embedded SiO 2 . Besides those results, the effects of other parameters such as the thickness of overlaying dielectric layer, shallow trench isolation, and silicon crystal orientations of [110] and [100] are also presented and discussed in this paper.

Since the curved surface of a cable-network reflector is generally approximated by regular flat facets, the electromagnetic performance of the cable-network reflector is determined by the size and shape of the facets. In many cases, the geometric approximation errors of the facets are periodically distributed on the surface, which can result in strong grating lobes. First, in this paper, the periodicity of the geometric approximation error and the effects of this periodicity on the EM performance are investigated. Second, the periodic geometric approximation errors of the regularly faceted configurations are disturbed by three proposed approaches, and three new types of surface configurations are thus formed. The first approach is to introduce radial direction disturbance parameters, the second one is to change the shape of the outlines and the last one is to use a Penrose-tiling-like configuration. The first two approaches are carried out in combination with the optimization strategies. Finally, the effects of the mentioned disturbance parameters on the EM performance are simulated, and some numerical examples are given to show that the surface configurations proposed in this paper can reduce the grating lobes level obviously, without either decreasing the gain or increasing the structural complexity of the cable-network reflectors.

Keller's landmark paper in 1962 formulated the Geometrical Theory of Diffraction (GTD). This was the beginning of a long process that brought the Geometrical Theory of Diffraction into practice, making it one of the most ubiquitous analysis methods in electromagnetics. This paper provides a personal historical trace of the Geometrical Theory of Diffraction: in particular, its further development in the 1970s and 1980s, and its realization into computer codes. The latter provided the first step for the analysis of complex realistic structures. The second half of the paper discusses the historical development of diffraction coefficients for impedance wedges using first- and higher-order generalized impedance boundary conditions.

In this paper, we derive an expression of the brightness temperatures of a vegetated surface based on the tau-omega model with the rough surface boundary condition that replaces the conventional exp(-h) model by NMM3D (Numerical Simulations of 3D Maxwell equations). A purpose of the paper is that the same physical rough surface scattering model based on NMM3D and the same physical parameters of rms heights and correlation lengths can be used for both passive and active remote sensing of the same scene of vegetated surfaces. The bistatic scattering of rough surfaces are decomposed into the coherent wave and the co-polarization and the cross-polarization of the incoherent waves to quantify the contribution of each of these components. Numerical results are illustrated for a variety of roughness conditions. Comparisons are made with the exp(-h) model. Results are compared with the experimental passive measurements of PORTOS 1993 for bare soil cases. Data cubes for grassland are calculated for both active and passive signatures at L band. Comparisons are then made with the L band PALS data for the grassland of SGP99 using these data cubes.

The rotation of human head and the eye are modeled as a perfect sphere with the rotation actuated by external torques. For the head movement, the axis of rotation is constrained by a law proposed in the 19th century by Donders. For the saccadic eye movement, Donders' Law is restricted to a law that goes by the name of Listing's Law. In this paper, head movement and saccadic eye movement are modeled using principles from classical mechanics and the associated Euler Lagrange's equations (EL) are analyzed. Geodesic curves are obtained in the space of allowed orientations for the head and the eye and projections of these curves on the space S2 of pointing directions of the eye/head are shown. A potential function and a damping term has been added to the geodesic dynamics from EL and the resulting head and eye trajectories settle down smoothly towards the unique point of minimum potential. The minimum point can be altered to regulate the end point of the trajectories (potential control). Throughout the paper, the restricted dynamics of the eye and the head movement have been compared with the unrestricted rotational dynamics on SO(3) and the corresponding EL equations have been analyzed. A version of the Donders' Theorem, on the possible head orientations for a specific head direction, has been stated and proved in Appendix I. In the case of eye movement, Donders' Theorem restricts to the well known Listing's Theorem. In Appendix II, a constraint on the angular velocity and the angular acceleration vectors is derived for the head movement satisfying Donders' constraint. A statement of this constraint that goes by the name “half angle rule,” has been derived.

In this paper, the discontinuous Galerkin (DG) finite-element time-domain (FETD) method is developed to model electromagnetic (EM) structures with waveguide excitations. Several specific issues about the DG-FETD modeling are addressed. First, the higher order tetrahedral elements are employed to accurately model the geometry of EM structures and effectively reduce the dispersion error so that the efficiency of the FETD method is increased. To further increase the efficiency of the DG-FETD method, the local time-stepping scheme is applied. Secondly, the conformal perfect matching layer (PML) is applied to terminate the waveguide. The formulation of the conformal PML is presented in this paper. Thirdly, a novel approach is proposed to extract the S-parameters of waveguide structures. This approach applies the surface magnetic current to excite the EM fields in the waveguide structures. Taking advantage of the relationship between the excitation current and excited fields in the uniform waveguide, one can readily obtain the incident electric fields that are required for calculating the S-parameters. This approach avoids the pre-simulation of the uniform waveguide. Finally, the numerical results are given to validate the DG-FETD modeling.

At low speed, the rotor-position estimation in sensorless control is often carried out based on the evaluation of the phase-current ripples resulting from the supply of high-frequency voltage test signals. However, the rotor-position estimation is affected by cross-saturation in the machine, resulting in less accurate position estimations at higher loads. As the importance of sensorless control of interior permanent-magnet synchronous machines (IPMSMs) increases, it is useful to design IPMSMs in such a way that they are optimized for accurate sensorless control. The goal of this paper is to determine design aspects in the rotor geometry of an IPMSM to minimize the position estimation error due to cross-saturation. Simulations of a sensorless drive are usually based on a state-space model with constant q- and d-axis inductances and no mutual inductances. In this paper, this technique is improved by calculating the inductance matrix from several finite-element models, which allows the study of the effect of variable q- and d-axis inductances and cross-saturation on the performance of the sensorless control. The rotor design is discussed, for both IPMSMs with and without flux barriers, in order to reduce the estimation error caused by cross-saturation.

This paper disproves an hypothesis that this author had made in an earlier paper from the observation that the values of the plane wave scattering coefficients computed with his numerical method could vary substantially with the physical separation distance between the integration box and the scatterer enclosed within the box. This variation was observed when the edges and corners of the integration box were strongly illuminated with the scattered field. It was hypothesized that this variation was due to the use of a box as the integration surface because a box is not the smooth integration surface that is supposed to be needed for the application of Huygens' principle on which is based the computation of the far-field values with the steady-state near-to-far field transformation. In this paper, it is found by reconstructing the spatial field distribution that corresponds to the error spectrum, and noting that this distribution is not confined to the edges and corners of the integration box, that the use of the box is not the cause for the variation and thus, that the hypothesis is false. It turned out that the variation nearly disappeared when the FDTD mesh size was of the order of 100 cells per wavelength. It is shown that the variation was due to the second-order accuracy of the FDTD stencil.

This paper describes a novel approach for extracting the centerline geometry of road/railway alignments in the form of traditional design elements (i.e., straight lines, circle arcs, and clothoids). As opposed to previous research, the proposed method attempts a completely general and a fully automated solution to the problem in a rigorous mathematical manner. Centerline locations originate in a ground-based mobile mapping system (e.g., global navigation satellite system/inertial navigation system vehicle trajectory or kinematic laser scanning profiles of the road/railway corridor). The core of the algorithm resides on the use, manipulation, and suitable reformulations of the bearing diagram of the centerline locations and its first- and second-order derivatives. To ensure highly accurate and consistent results, the algorithm practices a series of specifically designed/dynamically tuned filters that fully adhere to the fractal properties of the centerline location data. Extended test runs were undertaken to validate the correctness of the mathematical model and the feasibility of the algorithms and associated software. In this paper, test results using a simulated and a real (based on a multisensor geodetic survey) subset of a railway track data are discussed.

The problem of collision prediction in dynamic environments appears in several diverse fields, which include robotics, air vehicles, underwater vehicles, and computer animation. In this paper, collision prediction of objects that move in 3-D environments is considered. Most work on collision prediction assumes objects to be modeled as spheres. However, there are many instances of object shapes where an ellipsoidal or a hyperboloid-like bounding box would be more appropriate. In this paper, a collision cone approach is used to determine collision between objects whose shapes can be modeled by general quadric surfaces. Exact collision conditions for such quadric surfaces are obtained in the form of analytical expressions in the relative velocity space. For objects of arbitrary shapes, exact representations of planar sections of the 3-D collision cone are obtained.