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We establish a trace inequality of symplectic matrices via a more general trace minimization theorem. As a consequence, we derive another proof of a result in [R. Bhatia, T. Jain, On symplectic eigenvalues of positive-definite matrices, J. Math. Phys., 56 (2015),112201.]. [ABSTRACT FROM AUTHOR]

We in this paper define the outer-Perron-Frobenius splitting, which is an extension of the pseudo- Perron-Frobenius splitting defined in [A.N. Sushama, K. Premakumari, K.C. Sivakumar, Extensions of Perron-Frobenius splittings and relationships with nonnegative Moore-Penrose inverse, Linear and Multilinear Algebra 63 (2015) 1-11]. We present some criteria for the convergence of the outer-Perron-Frobenius splitting. The findings of this paper generalize some known results in the literatures.

In this paper, we establish a new version of a Schur–Horn type theorem. Meanwhile, we provide a new proof of a recent result in [Bhatia R, Jain T. A Schur-Horn theorem for symplectic eigenvalues. Linear Algebra Appl. 2020;599:133–139]. [ABSTRACT FROM AUTHOR]

Information on SARS-CoV-2 asymptomatic infection and infectivity in children is limited. In this study, we aimed to report the epidemiological and clinical characteristics of a familial cluster infection including children with SARS-CoV-2. On February 1, 2020, two children(case 1 and case 2), an 8-year-old girl and a 9-year-old boy, were admitted to the isolation ward in Xiangyang Central Hospital, Hubei province, China, with the diagnosis of COVID-19. Before admission, they had been staying at home with their father and never contacted with any confirmed patients except their mother (case 3) who returned from Wuhan on January 22. Both case 1 and case 2 got mild symptoms. Case 3 did not develop any symptoms until February 6, 2020, with an asymptomatic period of 15 days. She was transferred to ICU and administered multiple treatment according to the disease progression and chest CT manifestations. Her nucleic acid test turned positive until Feb 21, 2020, 15 days after symptoms onset, 30 days after her return from Wuhan. Our data showed that patients with SARS-CoV-2 may have the ability to transmit during their asymptomatic period even with the negative of viral nucleic acid in pharyngeal swabs. [ABSTRACT FROM AUTHOR]

In this paper, we prove that some recent Rotfel’d theorem extensions are equivalent. [ABSTRACT FROM AUTHOR]

The broadband Green's function with low wavenumber extractions (BBGFL) consists of low wavenumber method of moments (MoM) solutions combined with modal expansions. BBGFL is suitable for broadband simulations because the modal functions are independent of frequencies. The modal expansion in this paper has sixth-order convergence. Using wavenumber derivatives of the surface current, it is shown that the higher order extraction requires only a single MoM impedance matrix on the left-hand side. For the same number of modes, the sixth-order convergence has significant improvement in accuracy over the \textsecond - and \textfourth-order convergence. Scattering in an arbitrary-shape waveguide is modeled by using a surface integral equation formulated with the sixth-order BBGFL. Using BBGFL, the unknowns are only on the surface of the scatterer. Results of simulations are illustrated and the results are in good agreement with those of direct MoM. [ABSTRACT FROM AUTHOR]

We prove inequalities on non-integer powers of products of generalized matrices functions on the sum of positive semi-definite matrices. For example, for any real number, positive semi-definite matrices,, and generalized matrix functionssuch as the determinant and permanent, etc., we have A general scheme is introduced to prove more general inequalities involvingmpositive semi-definite matrices forthat extend the results of other authors. [ABSTRACT FROM PUBLISHER]

In this paper, the broadband Green’s function with low wavenumber extraction (BBGFL) is applied to modeling of traces connecting vias in arbitrarily shaped power/ground planes of printed circuit boards (PCBs). The proposed modeling method is a hybrid technique based on mode decomposition: BBGFL is used to fast compute the vias in power/ground planes, MoM is used to calculate the impedance matrix of the traces, and a physical circuit model is then applied to combine the vias and traces in the power/ground planes. The present method is compared to the method of moments (MoM) and the commercial tool HFSS. Results show that the results of the present technique are in good agreement with MoM and HFSS on the radiated emissions from PCBs. BBGFL is several hundred times faster than HFSS in CPU time for broadband simulations. The technique provides a fast broadband solution for system-level modeling of high-speed interconnects with vias and traces in electronic design automation design and applications. [ABSTRACT FROM AUTHOR]

The main purpose of this work is to present a better bound than the recent result given by Zhang [Linear Multilinear Algebra. 2015;63:2511–2517]. [ABSTRACT FROM AUTHOR]

In this paper, a novel termination (“match”) scheme is introduced with absorbing material for high-frequency measurements. Through the absorption of electromagnetic waves, absorbing material makes an equivalent absorbing boundary condition at the interface, which creates an equivalent termination condition. The absorbing termination can be used to facilitate on-demand match condition in high-frequency measurements. The proposed technique is particularly useful when resistive termination is difficult to implement or too expensive to apply. For example, the soldering process (soldering-on soldering-off) is time-consuming, hard to control on the precise soldering position, and easy to break the printed circuit board soldering pads. It is useful for various applications, including via crosstalk measurements in socket, package breakout via array, or other dense/fine structures. The absorbing termination method provides an innovative termination solution for RF/microwave measurements. [ABSTRACT FROM PUBLISHER]

In this paper, bond via array (BVA) wirebond is used to achieve compact vertical integration and improve the electrical performance for system in package (SiP). Two techniques are presented. In the first technique, BVA wirebonds are utilized to integrate some passive or active components vertically onto other components. This significantly reduces the horizontal footprint of the entire SiP. In terms of electrical performance, this vertical integration provides much lower parasitic inductance than conventional 2-D horizontal integration design because of shorter interconnection. For example, the proposed technology can significantly reduce power delivery network impedance compared to a conventional design. In the second technique, we propose BVA wirebond wires as an electromagnetic interference (EMI) shield between different domains within SiP. This provides a lower cost solution for EMI shielding, particularly when regions within a package need to be shielded. [ABSTRACT FROM PUBLISHER]

In this paper, we apply the broadband Green's function with low wavenumber extraction (BBGFL) to fast modeling of the radiated emissions from printed circuit boards (PCBs). We study power bus structures for electromagnetic interference/compatibility (EMI/EMC). We use the BBGFL to compute the Green's function over broadband frequencies along the boundary walls of arbitrarily shaped power/ground planes. The broadband Green's function is calculated by using modal expansions and low wavenumber extraction. Because the modal expressions are independent of frequencies, they are computed once and used for all frequencies. The radiated fields are derived from the equivalent magnetic surface currents on boundary walls using Huygen's equivalent principle. Results are illustrated up to 10 GHz and for arbitrary shaped PCB up to 5 inches in size. The accuracy and computational efficiency of the present method are compared with the method of moments (MoM) and the commercial tool HFSS. The BBGFL results are in good agreement with MoM and HFSS. The BBGFL is several hundred times faster than MoM and HFSS for broadband simulations. The significant improvement in computational efficiency makes this technique useful for electronic design automation to EMI/EMC applications. [ABSTRACT FROM PUBLISHER]

In this paper, we propose and investigate two novel applications of absorbing materials to suppress high-frequency couplings in high-speed interconnects. In the first application, absorbing materials are added to connector housing to reduce the noises caused by crosstalk and resonances. In the second application, a low-emission inductor is proposed by applying absorbing materials surrounding the body of an inductor. Full-wave simulations and measurements are performed to verify the proposed techniques. Results show absorbing materials significantly improve the performance of signal/power integrity and greatly reduce electromagnetic interference for high-speed digital system designs. [ABSTRACT FROM PUBLISHER]

A new technology is developed for the mitigation of stub effects in high-speed interconnects. This technology substantially reduces the stub effects for high-speed signaling. It dampens reflected signals on stubs, thus reducing intersymbol interference and harmful coupling, and correcting timing jitter, all typically induced by the stub’s reflected signals. This paper shows two applications for high-speed digital system designs, the mitigation of via stub effects and that of empty connector effects, respectively. However, it is notable that the present method is suitable for reflection suppression for arbitrary types of stubs to improve the signal integrity. [ABSTRACT FROM PUBLISHER]

We extend the 3-D numerical method of Maxwell's equation (NMM3D) for rough soil surface scattering from L-band to C-, X-, and Ku-bands. We illustrate the results for copolarization, cross-polarization, and polarization ratio (HH/VV). Copolarized and cross-polarized backscattering coefficients from NMM3D are analyzed for frequency dependence, incident angle dependence, and soil moisture dependence. We also cross compare results from analytical and empirical models. The 16 $\times$ 16 squared wavelength $(\lambda^2)$ of rough surface is applied for NMM3D using 256 processors on NSF Extreme Science and Engineering Discovery Environment clusters. Polarization ratio, HH/VV, is studied to address the feature of dependence on frequency for same fields (same physical parameters for the model). HH/VV is shown useful to provide additional information to study land surface. Results from NMM3D are also validated with POLARSCAT measurement data-1. NMM3D shows good agreement with data and better performance while considering copolarization, cross-polarization, and polarization ratio (HH/VV) together. The key advancement in computation efficiency in this paper is the implementation of a physically based near-field precondition algorithm in NMM3D to accelerate parallel computation. With precondition, the computation time is faster by ten times for larger root-mean-square height. [ABSTRACT FROM PUBLISHER]

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 paramters 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. [ABSTRACT FROM PUBLISHER]

Active and passive microwave remote sensing has been used for monitoring the soil moisture and snow water equivalent. In the interactions of microwaves with bare soil, the effects are determined by scattering of electromagnetic waves by random rough surfaces. In the interactions of microwaves with terrestrial snow, the effects are determined by volume scattering of dense media characterized by densely packed particles. In this paper, we review the electromagnetic full-wave simulations that we have conducted for such problems. In volume scattering problems, one needs many densely packed scatterers in a random medium sample to simulate the physical solutions. In random rough surface scattering problems, one needs many valleys and peaks in the sample surface. In random media and rough surface problems, the geometric characterizations of the media and computer generations of statistical samples of the media are also challenges besides electromagnetic computations. In the scattering of waves by soil surfaces, we consider the soil to be a lossy dielectric medium. The random rough surface is characterized by Gaussian random processes with exponential correlation functions. Surfaces of exponential correlation functions have fine-scale structures that cause significant radar backscattering in active microwave remote sensing. Fine-scale features also cause increase in emission in passive microwave remote sensing. We apply Monte Carlo simulations of solving full 3-D Maxwell's equations for such a problem. A hybrid UV/PBTG/SMCG method is developed to accelerate method of moment solutions. The results are illustrated for coherent waves and incoherent waves. We also illustrate bistatic scattering, backscattering, and emissivity which are signatures measured in microwave remote sensing. For the case of scattering by terrestrial snow, snow is a dense medium with densely packed ice grains. We have used two models: densely packed particles and bicontinuous media. For the case of densely packed particles, we used the Metropolis shuffling method to simulate the positions of particles. The particles are also allowed to have adhesive properties. The Foldy–Lax equations of multiple scattering are used to study scattering from the densely packed spherical particles. The results are illustrated for the coherent waves and incoherent waves. For the case of bicontinuous media, the method developed by Cahn is applied to construct the interfaces from a large number of stochastic sinusoidal waves with random phases and directions. The volume scattering problem is then solved by using CGS–FFT. We illustrate the results of frequency and polarization dependence of such dense media scattering. [ABSTRACT FROM PUBLISHER]

A hybrid UV/PBTG/SMCG method is developed to accelerate the solution of NMM3D for 3-D electromagnetic wave scattering by random rough soil surfaces. It takes only 1.5 min using 16 processors on a cluster of NSF TeraGrid to compute 3-D solution of Maxwell equations of 8 by 8 square wavelengths. With the improved computational efficiency, we computed results using areas up to 32 by 32 square wavelengths. With the larger surface area, we were able to compute cases with larger rms heights up to 8 cm at SMAP radar frequency of 1.26 GHz that corresponds to kh = 2.28. New results computed include the cross-polarization. The five tests on the accuracy of results were performed: convergence with realizations, convergence with discrete samplings, convergence with sample surface sizes, energy conservation for each realization, and reciprocity for each realization. The numerical results show that for a single realization VH = HV within 0.5 dB in the backscattering direction showing that reciprocity is obeyed. Results were compared with experimental data, and both co-polarization and cross-polarization were in good agreements with experimental data. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, The Weighted Moore-Penrose of intuitionistic fuzzy matrices and weighted left (right) cancelable intuitionistic fuzzy matrices were defined. Finally we derive the equivalent condition for the existence of the Weighted Moore-Penrose and give an algorithm for computing the Weighted Moore-Penrose of Intuitionistic Fuzzy Matrices. [Copyright &y& Elsevier]

A series of bimetallic rare-earth complexes {[μ-η1:(μ-η1:η1):η1-1-(2-C5H4N)-3-(2-C7H4NS)C8H4N]RE(CH2SiMe3)2}2 (RE = Y(7a), Er(7b), Yb(7c), Lu(7d)) were synthesized by treatment of rare-earth metal trialkyl complexes RE(CH2SiMe3)3(THF)2 with one equiv. of the proligand 1-(2-C5H4N)-3-(2-C7H4NS)C8H5N (6) in good isolated yields. Complex 7c can be converted to the divalent rare-earth metal complexes (η4:σ:κ1-L)2YbII [L = 1-(2-C5H4N)-3-(2-C7H4NS)C8H4N(CHSiMe3)] (8) at elevated temperature in toluene solution. Complexes 7a, 7d and 8 were characterized by NMR spectroscopy. Additionally, the yttrium (7a), erbium (7b) and lutetium (7d) complexes exhibited high activity in the polymerization of 2-vinylpyridine with isotactic selectivity and high molecular weight. [ABSTRACT FROM AUTHOR]

Track Editors Maurizio Bozzi Zhizhang D. Chen James Hwang Natalia Nikolova David Ricketts Anding Zhu [ABSTRACT FROM AUTHOR]

Presents a listing of reviewers who contributed to this publication in 2018. [ABSTRACT FROM AUTHOR]

In this paper, we present an approach to reduce the cavity resonant edge effects in printed circuit boards (PCBs) and semiconductor packages. Power supply noise, in the form of fast changing currents (di/dt), traverses the power-return paths of PCBs and semiconductor packages using power vias. The cavity effects produce considerable level of noise along the edges of PCB and integrated circuit (IC) package power planes due to signal coupling between vias and reflection from PCB edges with transient currents. The cavity effects also amplify the electromagnetic radiation from PCB edges, which are major sources of EMI/EMC problems in electronic devices. By using absorbing material and decoupling capacitors (de-caps) on power distribution networks (PDNs), we observe considerable mitigation in impedance noise, signal noise and electromagnetic interference/compatibility (EMI/EMC) issues caused by the cavity effects. In particular, simulation results show notable reduction of upper peak (anti-resonant) impedance noise and reduction in radiated emissions by as much as 20 dB. This article presents a comparative case-study using various models (Section 3) and report on their effectiveness to reduce the cavity effects. The models are listed as (1) "Original" model, (2) "Absorbing material along the edge" model, (3) "MURATA based De-cap only" model and (4) "Absorbing material along the edge w/De-cap" model. The used capacitance ranges between 0.1 μF and 22μF. The ESR and ESL range between 2mOhm-20mOhm and 238 pH-368 pH, respectively. Conclusively, we learn by adding absorbing material along the PCB edges with a few decoupling capacitors. The PDN impedance noise is improved and EMI issues in PCBs and semiconductor packages suppress the cavity effects. [ABSTRACT FROM AUTHOR]

In this paper, a novel broadband equalizer optimization technique is introduced for high-speed digital system designs. Through effectively compensating both conductor loss and dielectric loss, this technique provides a new solution to find optimal equalizer for high-speed signaling over printed circuit board (PCB) with continuous time linear equalizer (CTLE) as an application. The coefficients of CTLE are quickly identified through searching the minimum of the variation of total transfer functions over the low-mid frequency range. Channel simulations with different server interfaces of 12Gbps and 25 Gbps are performed, respectively. Simulation results are presented to validate the technique. [ABSTRACT FROM AUTHOR]

In this paper, a new de-embedding technique with Look-Up Table (LUT) is proposed for accurate and efficient characterization of interconnects, particularly printed circuit board (PCB) transmission lines including microstrip and stripline. LUT is pre-created to cover various fixture effects including the reference structures inside and/or outside test printed circuit boards (PCBs). The pre-established LUT is introduced to eliminate the errors of "probing and launching fixtures" in characterization of transmission lines. It is applied to characterization of loss of microstrip and stripline. Simulations and measurements are performed to verify its accuracy and feasibility. Results show it is in good agreement with conventional Delta-L like methods but significantly reduces the cost of characterization. It provides an accurate but cost-effective solution for characterization of high speed interconnects, in particular for high volume manufacturing environments. [ABSTRACT FROM AUTHOR]

An abstract of the article "High-density SNP-based genetic map for Odontobutis potamophila" by Hongwei Zhang and colleagues is presented.