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The influence of nonuniform aging has not been considered in the prediction of the frequency domain spectroscopy (FDS) of the transformer oil-paper insulation (OPI) when using the finite element method (FEM). Given this issue, the modified simulation model was constructed based on the XY model and FEM. In the current work, the dielectric response property of the pressboards with different aging conditions in the modified model was characterized by its dielectric response parameters measured in the lab. Then the modified simulation model constructed in a 3-D system would be applied to study the effect of both nonuniform aging and the axial geometry on the FDS of OPI. Finally, the feasibility of the proposed models was verified by comparing the measured FDS and the predicted FDS. This article is expected to provide a model for predicting the FDS of the transformer OPI including the effect of nonuniform aging. [ABSTRACT FROM AUTHOR]

This paper proposed a simulation method for the charge transport in single-layer oil-paper insulation. The method of transient upstream finite-element method (FEM) is derived in order to calculate the time variation of charge densities in medium. The numerical simulation of charge transport in the single-layer oil-paper insulation is realized by applying the transient upstream FEM to the transport equations of bipolar charges. With reasonable microparameter, the charge transport in an experimental object is simulated. The simulation results are consistent with the experimental data. A bent model of oil-paper insulation is analyzed to study the charge distribution under the actual condition. This paper provides an exploratory research to the simulation of charge phenomenon in oil-paper, and has guiding significance to the design of oil-paper insulation. [ABSTRACT FROM AUTHOR]

This paper deals with a low-cost method for the assembly of flexible substrate antennas and UHF RF identification silicon (Si) chips. Such a method exploits a magnetic coupling mechanism, thus not requiring for galvanic contacts between the Si chip and antenna itself. The magnetic coupling is established by a planar transformer, the primary and secondary windings of which are implemented on flexible substrate and Si chip, respectively. As a result, the Si chip can be assembled on the antenna with a mere placing and gluing process. First, the idea has been validated by theory. Electromagnetic simulations of a square heterogeneous transformer (1.0-mm side) show a maximum available power gain (MAG) of -0.4 dB at 868 MHz. In addition, the heterogeneous transformer is also quite tolerant with respect to misalignment between primary and secondary. An offset error of 150 \mu\ m reduces the MAG to -0.5 dB. A sub-optimal matching strategy, exploiting a simple on-chip capacitor, is then developed for antennas with 50-\Omega input impedances. Finally, the idea has been experimentally validated exploiting printed circuit board (PCB) prototypes. A PCB transformer (1.5-mm side) and a transformer rectifier (two-diode Dickson multiplier) have been fabricated and tested. Measurements indicates a MAG of -0.3 dB at 868 MHz for the transformer and the capability of the developed rectifier to supply a 220-\k\Omega load at 1.5 V with a -2-dBm input power. [ABSTRACT FROM AUTHOR]

This article discusses the 2017 ACM SIGARCH/IEEE-CS TCCA Influential ISCA Paper Award, which was given to the 2002 ISCA paper, “Drowsy Caches: Simple Techniques for Reducing Leakage Power.” [ABSTRACT FROM AUTHOR]

This paper proposes a new method to improve re performance of intra-field interpolation which is the mos~ important element of deinterlacing method. Traditional edge- based methods were poor at determining accurate edge iirection which decides interpolation performance. The 7roposed method decides the direction and slope of edge based on locally adaptive-thresholded binary image to mprove efficiency and accuracy, and it also increased the ~orizontal size of search window to 15 for better direction ietermination at gentle slope. Compared to traditional edge- based methods, interpolation based on binary image, which is ,`enerated using the proposed method, leads to great erformance improvement. With computer simulations for a ~`ariety of images, this paper shows the new approach is much ~etter than traditional methods.. [ABSTRACT FROM AUTHOR]

This paper presents an implementation of an ~daptive beamformer in a hands-free unit. The proposec~ ~daptive beamformer suppresses stationary noise an~ nterference sound. The adaptive beamformer and acoustic `cho canceller were implemented in a compact hands-free mit with a low-cost DSP. Experimental results demonstrate he noise reduction performance of the hands-free unit'. [ABSTRACT FROM AUTHOR]

In a series of papers by Pawlikowski and his team, they warned about a deep crisis of credibility in simulation studies for the performance evaluation of telecommunication networks. The goal of this article is to revisit the investigation on simulation credibility and to extend the previous research in this area by presenting the results of a comprehensive survey of over 8370 IEEE publications (2007?2009) on telecommunication networks which appeared in the proceedings of IEEE Transactions on Communications (TC), IEEE/ACM Transactions on Networking (TN), IEEE Infocom, IEEE ICC, and IEEE Globecom. These proceedings were selected based on their popularity and relevance to our study. Besides simulation credibility, we also report on the commonly used simulation tools and performance analysis methodology adopted by the authors of the surveyed papers. Our findings show that a significant number of authors did not provide information of the simulation tools used or, even when they did, there was not enough information about the CI or SE of simulation results presented in the surveyed papers. Thus, there is no significant change with respect to quality and credibility of the simulation studies revised and the deep crisis of credibility still remains. The research design most authors prefer is a hybrid one where both simulation and analytic methods are being used for network performance analysis. Finally, we provide guidelines for the best practice of using simulation tools for the performance evaluation of telecommunication networks. [ABSTRACT FROM PUBLISHER]

Most of the literatures dealing with time domain simulation of grounding system response to lightning surges use an electrostatic approach. In this approach frequency dependence of soil electrical parameters and plane-wave propagation constant are not included. In this paper, based on Hybrid Electromagnetic Method and simplification of it, a new method is developed to include frequency dependent parameters of soil in time domain simulation. Since only one convolution is used, the simulation time is significantly reduced. The consistency of the developed formulation while the plane-wave propagation constant is ignored is investigated through comparisons with experimental results and precise frequency domain approaches. Simulations results show ignoring both effects simultaneously can lead to high levels of error (140%), whereas the error significantly reduces when frequency dependence of soil parameters is considered. The developed model exhibits errors of about 2% to 25% compared to the results of models that take into account both effects. However, simulation results showed all these errors to be conservative. Due to neglecting propagation constant, the model is more suitable for lightning studies of grounding system with short length. [ABSTRACT FROM AUTHOR]

In this paper, we propose a design process for a plasmonic grating structure to induce the resonance at a target wavelength. In a specific condition, surface gratings may induce the surface plasmon propagation due to the diffraction and the resonance wavelength of the surface plasmon propagation is dependent on the grating shape. The grating configuration was designed by the topology optimization scheme based on the reaction-diffusion equation. To shift the resonance wavelength to the target wavelength, this paper maps the frequency response function to a probability distribution function (PDF). The mean value from the PDF becomes a part of the objective function and the design objective is set to minimize the distance between the present resonance wavelength and the target wavelength while keeping the energy intensity. The process of simulation and optimization was performed using the commercial package COMSOL combined with MATLAB programming. [ABSTRACT FROM AUTHOR]

This paper presents the results of mathematical simulation of processes in argon-hydrogen inductively coupled plasma/radio frequency induction plasma torch for plasma chemical reactions. This first part starts a series of papers for simulation and study of plasma properties for a variety of gases and mixtures, which could be used for a number of prospective technologies. The results of mathematical simulation allow further research on the mechanisms of chemical reactions in argon-hydrogen plasma to increase effectiveness of obtaining the target product. [ABSTRACT FROM AUTHOR]

Using the barometer for height estimation often requires the use of external reference to correct biases in measurement. These biases are often caused by the change of the ambient pressure environment. The barometric height estimation is especially challenging in tactical and rescue applications where high temperatures or sudden large pressure shocks can change the pressure rapidly. We assess the suitability of barometers for infrastructure-free navigation in tactical applications. First, this paper investigates the effect of transition in seamless indoor/outdoor navigation. Second, we measure the effects of pressure shocks, caused by explosions or firearms, on low-cost and lightweight micro-electromechanical barometers to ensure that the sensors are capable of operating under these conditions. Finally, we investigate the use of sonar measurement to estimate the vertical speed as an alternative to the reference barometer for infrastructure-free navigation. The fusion of barometer and sonar achieved on average 0.46-m root-mean-square error (RMSE) while simple barometric height estimation had a RMSE of 0.65 m. The fusion method had no errors over 1.5 m during the test. This accuracy is generally sufficient to find the correct floor level which is crucial for tactical situational awareness. The goal of this paper is to develop the methods for seamless indoor/outdoor navigation, and therefore the most important result of this paper is that the error caused when transitioning between outdoor and indoor environments is visibly reduced. [ABSTRACT FROM AUTHOR]

Innovations in biomedical ultrasonics cannot be materialized without foundational advances in experimental methods, tools, and protocols. For instance, innovations in ultrasound imaging are often backed up by various investigative and validation tools including, but not limited to: 1)simulation programs, 2)phantom fabrication techniques, and 3)real-time computing frameworks. In the emerging field of therapeutic ultrasound, fundamental advances in engineering methods have also made significant contributions to the the discipline's technical progress. Well-known examples include: 1)techniques for synthesizing microbubbles and nanodroplets, 2) rational design approaches for acoustic exposure instruments, and 3) establishment of suitable cellular and animal models relevant to therapeutic ultrasound experimentation. Nevertheless, these essential techniques and protocols have not always been reported in depth, and many technical details have been relegated as black-box processes in research articles. There is a dire need for a more concentrated effort on the reporting of the key methods used in contemporary biomedical ultrasound research. [ABSTRACT FROM AUTHOR]

Availability of a common, shared benchmark to provide repeatable, quantifiable, and comparable results is an added value for any scientific community. International consortia provide benchmarks in a wide range of domains, being normally used by industry, vendors, and researchers for evaluating their software products. In this regard, a benchmark of untimed Petri net models was developed to be used in a yearly software competition driven by the Petri net community. However, to the best of our knowledge there is not a similar benchmark to evaluate solution techniques for Petri nets with timing extensions. In this paper, we propose an evaluation framework for the comparative analysis of generalized stochastic Petri nets (GSPNs) simulation techniques. Although we focus on simulation techniques, our framework provides a baseline for a comparative analysis of different GSPN solvers (e.g., simulators, numerical solvers, or other techniques). The evaluation framework encompasses a set of 50 GSPN models including test cases and case studies from the literature, and a set of evaluation guidelines for the comparative analysis. In order to show the applicability of the proposed framework, we carry out a comparative analysis of steady-state simulators implemented in three academic software tools, namely, GreatSPN, PeabraiN, and TimeNET. The results allow us to validate the trustfulness of these academic software tools, as well as to point out potential problems and algorithmic optimization opportunities. [ABSTRACT FROM AUTHOR]

The article offers information on the publication of "IEEE Transactions on Computational Social System" and topics covered under the publication which include modeling, simulation and understanding of social system from computational perspectives. The article covered in the publication include social network dynamics, social intelligence and cognition, and computational behavior modeling.

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM PUBLISHER]

An introduction is presented in which the editor discusses various reports within the issue on topics including role of simulation technology, application of electrical circuit simulations in hybrid vehicle development, and Insulated Gate Bipolar Transistor (IGBT).

This paper proposes a new design methodology of dual-band stripline circulator for wireless communications applications. As far as the monoband classic circulator is based on coupling the counter-rotating fundamental modes, the operating principle of dual-band phenomenon is based on studying both fundamental and upper resonant modes within ferrite disks. Electromagnetic (EM) simulations have shown that two categories of dual-band operation could be obtained: simple (unidirectional) and left-handed /right-handed (LH–RH) circulators. The application dedicated to these two original concepts will be discussed, and simulation results will be ensured by the measurement of two prototypes in order to validate the methodology’s reliability. [ABSTRACT FROM AUTHOR]

In this paper, a complete flux scheme (CFS) has been implemented in 1-D fluid model for simulating the pulsed dielectric barrier discharge (DBD) in pure argon at atmospheric pressure. The characteristic quantities of the pulsed DBD have been systematically calculated by using the CFS and presented in comparison with those by using the exponential difference scheme (EDS). This paper shows the following results. There is the two-pulse discharge mode in the present simulation. The two discharge currents obtained using the CFS and EDS converge to the same result in good agreement with the experiment as spatial step length decreases, but the CFS has a fast convergence performance compared to the EDS. With a small grid number, the numerical scheme has an evident effect on the characteristic quantities in the time region corresponding to the first discharge pulse. This paper suggests that in the pulsed DBD, the usage of the CFS with a properly small grid number can give more accurate result and also presents a high calculation efficiency. [ABSTRACT FROM AUTHOR]

The active contour model is a widely used technique for automatic object contour extraction. Existing methods based on this model can perform with high accuracy, even in the case of complex contours, but challenging issues remain, like the need for precise contour initialization for high curvature boundary segments or the handling of cluttered backgrounds. To deal with such issues, this paper presents a salient object extraction method, the first step of which is the introduction of an improved edge map that incorporates edge direction as a feature. The direction information in the small neighborhoods of image feature points is extracted, and the images’ prominent orientations are defined for direction-selective edge extraction. Using such improved edge information, we provide a highly accurate shape contour representation, which we also combine with texture features. The principle of the paper is to interpret an object as the fusion of its components: its extracted contour and its inner texture. Our goal in fusing textural and structural information is twofold: it is applied for automatic contour initialization, and it is also used to establish an improved external force field. This fusion then produces highly accurate salient object extractions. We performed extensive evaluations, which confirm that the presented object extraction method outperforms parametric active contour models and achieves higher efficiency than the majority of the evaluated automatic saliency methods. [ABSTRACT FROM AUTHOR]

Isentropic compression experiments (ICEs) are an important method to study the dynamic characteristics of materials at pressures, temperatures, and stress or strain rate not attainable in conventional shock experiments. Yet it makes high demands toward the precise current pulse tailoring capability of the source. The China Academy of Engineering Physics is now developing a 20-brick parallel discharge driver and a 256-brick parallel discharge driver (CQ-7) to improve the performance and flexibility of compact magnetic compression devices. The load current of ICEs is tailored by optimizing the switch trigger sequence and the brick charging voltage. This paper establishes the equivalent circuit model of the 20-brick parallel discharge driver, taking the distributed inductance, resistance, and capacitance of transmission plates into account based on the partial-element equivalent circuit method. Besides, the equivalent circuit model of discharge brick based on the switch arc resistance model is also established to study the influence of key structural parameters on the output current. Furthermore, by comparing the simulation and experimental results of simultaneous discharge of 20-brick driver, the accuracy of simulation model is confirmed. This paper is of great significance to the design and optimization of multibrick parallel discharge drivers. [ABSTRACT FROM AUTHOR]

The IEEE International Integrated Reliability Workshop (IIRW) focuses on ensuring electronic device reliability through fabrication, design, testing, characterization, and simulation, as well as identification of the defects and physical mechanisms responsible for reliability problems. Submit your two-page abstract by 12 July 2013 to be part of this unique event. For further information visit http://www.iirw.org or contact the TPC chair. [ABSTRACT FROM AUTHOR]

There are few of transient control models are adapted to asynchronous induction coil launcher (AICL) with air core coil. Thus, many papers about AICL were written with the goal of increasing muzzle velocity of projectile. This paper concentrate on how to control the projectile speed and thrust accurately by using improved current filament (CF) method and variable voltage variable frequency (VVVF) scheme. The improved CF method contains mathematical model of three-phase inverter based on switch function, including conventional two level converter and cascaded multilevel converter models. The whole launch process is programmed with MATLAB. Simulation results show that this scheme have a smoother thrust fluctuation on projectile than other driving models. The motor parameters are changing with the temperature and frequency in launching process. Hence, the constant voltage frequency ratio (V/f) in this paper is more simple and reliable than vector control. To verify the control model and simulation results, a nine stages coil launcher prototype is constructed. The measured force and muzzle velocity are basically consistent with simulation results. It is proved that the improved CF method and VVVF strategy is feasible, and it is characterized by its small calculating amount that make it a valuable tool for design of AICL. The simple and excellent control of the thrust during launch process avoids load peaks, which means that the payload is handled more carefully compared to the classical launchers. [ABSTRACT FROM PUBLISHER]

This paper presents an analysis based on recent Electric Power Research Institute research in which a comparison is made between the “loss factor” calculated directly from annual simulations and a loss factor estimated variously from established equations and published papers and articles. The analysis provides new insights into the use of loss factors in estimating feeder losses. Sources of possible errors are identified and quantified. [ABSTRACT FROM PUBLISHER]

In this paper, a low-complexity color interpolation algorithm is proposed for the very-large-scale integration (VLSI) implementation in real-time applications. The proposed novel algorithm consists of an edge detector, an anisotropic weighting model, and a filter-based compensator. The anisotropic weighting model is designed to catch more information in horizontal than vertical directions. The filter-based compensation methodology includes a Laplacian and spatial sharpening filters, which are developed to improve the edge information and reduce the blurring effect. In addition, the hardware cost was successfully reduced by hardware sharing and reconfigurable design techniques. The VLSI architecture of the proposed design achieves 200 MHz with 5.2-K gate counts, and its core area is 64~236~\mu m ^{\mathrm {\mathbf {2}}} synthesized by a 0.18- \mu $ m CMOS process. Compared with the previous low-complexity techniques, this paper not only reduces gate counts or power consumption by more than 8% or 91.7%, respectively, but also improves the average color peak signal-to-noise ratio quality by more than 1.6 dB. [ABSTRACT FROM PUBLISHER]

The intelligent estimation method (IEM) is based on approximations which can be described by the configuration and behavioral characteristic of the problem. This paper used the IEM in time domain (IEM-TD) which can be utilized to predict the current distribution and maximum current density. A detailed IEM technique to compute the current distribution over the surface of a rail, current profile around the rail, and maximum current density ( J\max) formula will be presented in this paper. The current distribution is computed for rectangular and circular rails that are shown in color figures. Finally, this paper considers the effect of the rail dimensions and material on these parameters that are shown in several figures. The results of this paper are compared to other published studies and FEM simulation. [ABSTRACT FROM AUTHOR]

The use of Miller's Theorem in the determination of the high-frequency cutoff frequency of transistor amplifiers was recently challenged by a paper published in this TRANSACTIONS. Unfortunately, that paper provided no simulation or experimental resuIts to bring credence to the challenge or to validate the alternate method of determination proposed. This paper provides SPICE simulation results that validate the common usage of Miller's Theorem, limit the alternate method provided in that recent paper to a very small class of amplifiers, and reinforce the need to consider transistor amplifiers as two-pole systems. [ABSTRACT FROM AUTHOR]

This paper presents an FPGA-based Digital Real-Time Simulation (DRTS) environment for the analysis of Electromagnetic Transients (EMTs) of power systems that include multiple Power Electronic Converters (PECs). The main features of the proposed DRTS platform are that it i) employs two-value resistor switch model for PECs and thus avoids inaccuracies of Associate Discrete Circuit (ADC) model and ii) does not require separation of PECs by transmission lines (stub lines) and thus accurately represents PECs in close electrical proximity of each other. These features respectively result in a time-variant and large system admittance matrix which significantly increases the computation burden in each simulation time-step and can render it infeasible for real-time applications. To overcome this problem this paper introduces i) Switching-Network Partitioning (SNP) method which is tailored for PECs representation in FPGA and ii) Reformulated Modified Nodal Analysis (RMNA) method to enable computational parallelism between the solution of network and component models in FPGA. SNP enables solution-level partitioning of the PECs and the rest of the system. The developed DRTS platform enables sub-microsecond simulation time-step and provides a fixed hardware irrespective of the system configuration. Performance of the platform is evaluated for a study system and verified versus off-line simulation studies. [ABSTRACT FROM AUTHOR]

The paper discusses the modeling and the simulation of the limiters of proportional integral (PI) controllers included in voltage-sourced converters. Seven PI controller models are considered. These include windup and anti-windup limiters, back calculation with different gains and delayed feedback and the model recommended by the IEEE standard 421.5-2016. The dynamic behavior and numerical issues arising for each PI implementation are thoroughly compared by means of a detailed all-island dynamic model of the Irish system including the HVDC East–West Interconnector and a simplified dynamic model of the Great Britain system; and the Nordic system with inclusion of a STATCOM device. Recommendations on the computer-based implementation of each model are provided in the concluding remarks. [ABSTRACT FROM AUTHOR]

Energy efficiency has become the main concern of IC technology. Tunnel FET (TFET) is recognized to possess the superiority of energy efficiency over MOSFET at ultralow voltage, while variability might limit the voltage reduction and thus the energy saving. Recently, device source doping gradient (SDG) is found to be the dominant variation source in TFET. In this paper, for the first time, with the awareness of SDG variation, the energy efficiency of TFET-based circuits with different activity factors ( $\alpha $ ) is comprehensively reassessed and the device optimization strategy is provided. It is found that the superiority of energy efficiency of TFET will significantly decrease especially for the more active circuit due to the inherent tradeoff between SDG variation and nominal SDG. Based on the quantitative relationship between SDG variation and nominal SDG extracted from the experimental devices, the optimal design of tunnel junction abruptness to maximize the circuit energy efficiency is obtained, leading to significant energy efficiency improvements of TFET-based circuit over MOSFET even for circuit with high $\alpha $. This paper provides helpful device design guidelines for TFET with device variability awareness from the perspective of circuit energy efficiency. [ABSTRACT FROM AUTHOR]

This paper considers the problem of estimating a high-dimensional vector of parameters \theta \in \mathbb R^n from a noisy observation. The noise vector is independent identically distributed Gaussian with known variance. For a squared-error loss function, the James–Stein (JS) estimator is known to dominate the simple maximum-likelihood (ML) estimator when the dimension n exceeds two. The JS-estimator shrinks the observed vector toward the origin, and the risk reduction over the ML-estimator is greatest for {\theta } that lie close to the origin. JS-estimators can be generalized to shrink the data toward any target subspace. Such estimators also dominate the ML-estimator, but the risk reduction is significant only when {\theta } lies close to the subspace. This leads to the question: in the absence of prior information about \theta , how do we design estimators that give significant risk reduction over the ML-estimator for a wide range of \theta ? In this paper, we propose shrinkage estimators that attempt to infer the structure of \theta from the observed data in order to construct a good attracting subspace. In particular, the components of the observed vector are separated into clusters, and the elements in each cluster shrunk toward a common attractor. The number of clusters and the attractor for each cluster are determined from the observed vector. We provide concentration results for the squared-error loss and convergence results for the risk of the proposed estimators. The results show that the estimators give significant risk reduction over the ML-estimator for a wide range of \theta , particularly for large $n$ . Simulation results are provided to support the theoretical claims. [ABSTRACT FROM AUTHOR]

The pseudospectral analytical time-domain (PSATD) particle-in-cell algorithm solves the vacuum Maxwell's equations exactly, has no Courant time-step limit (as conventionally defined), and offers substantial flexibility in plasma and particle beam simulations. It is, however, not free of the usual numerical instabilities, including the numerical Cherenkov instability, when applied to relativistic beam simulations. This paper presents several approaches that, when combined with digital filtering, almost completely eliminate the numerical Cherenkov instability. This paper also investigates the numerical stability of the PSATD algorithm at low beam energies, drawing in many cases on the pioneering work of Prof. Ned Birdsall, in whose memory this paper is dedicated. [ABSTRACT FROM PUBLISHER]

This paper is part of the EFDAs European goal oriented training program on remote handling (RH) GOT-RH. The program aims to train engineers for activities supporting the ITER project and the long-term fusion program. This paper is written based on the results of a project verification and validation (V&V) of ITER RH system using digital mock-ups (DMUs). The purpose of this project is to study an efficient approach of using DMU for the V&V of the ITER RH system design using a system engineering framework. This paper gives an overview of the current trends in product and simulation lifecycle management (PLM/SLM) in the industry. This paper suggests a design verification process centralized around a collaboration platform. The purpose of this paper aims at improving and formalizing the ITER RH design process together with the V&V process. The objective of the suggested process is to improve the cost efficiency and reliability of ITER RH systems. [ABSTRACT FROM PUBLISHER]

This paper outlines a method using finite-element analysis (FEA) to model the magnetization process of a small brushless surface-magnet three-phase motor with isotropic ferrite magnets and concentrated windings. This is aimed at allowing in situ magnetization using the three-phase machine winding. Radial magnetization is the nominal manufactured magnetization pattern; however, the in situ method leads to a variation in the magnetization pattern, and the performance is examined using open-circuit simulations. The properties of the magnet material (a ferrite 5 type) are examined in order to simulate the magnetization. Bulk magnetization Hs\-sat levels for ferrite type 5 indicate that a 10-kOe field is required. In this paper, localized magnetization is examined using FEA, and it is measured in actual rotors by examination of the surface flux density when removed from the stator. Methods for deriving the approximate back electromotive force from both the FEA and the surface measurements are put forward; these show a reasonable correlation. The use of magnetization functions allows the magnetization pattern to be applied to the simulations. This paper uses a standard manufactured machine to carry these out. Open-circuit experiments are conducted to validate the presented method. [ABSTRACT FROM AUTHOR]

Frequency response analysis (FRA) has been globally accepted as a reliable tool to detect mechanical deformation within power transformers. However, because of its reliance on graphical analysis, interpretation of FRA signature is still a challenging area that calls for skilled personnel, as so far, there is no widely accepted reliable standard code for FRA signature identification and quantification. While several papers investigating the impact of various mechanical winding deformations on the transformer FRA signature can be found in the literature, no attention was given to investigate the impact of various bushing faults and transformer oil degradation on the FRA signature. This paper introduces a detailed simulation and practical analyses to elaborate the impact of bushing faults as well as transformer oil degradation on the transformer FRA signature. In this regard, the physical geometrical dimension of a three phase power transformer is simulated using 3D finite element analysis to emulate the real transformer operation. Various bushing faults have been emulated on the studied model and oil degradation is implemented through changing oil permittivity. Practical FRA test is conducted on a three phase 132 kV, 35 MVA power transformer to validate the simulation results. Results show that bushing faults and oil degradation can be visibly detected through FRA signature. [ABSTRACT FROM PUBLISHER]

Numerous research efforts have been conducted to simulate the crowd movements, while relatively few of them are specifically focused on multihazard situations. In this paper, we propose a novel crowd simulation method by modeling the generation and contagion of panic emotion under multihazard circumstances. In order to depict the effect from hazards and other agents to crowd movement, we first classify hazards into different types (transient and persistent, concurrent and nonconcurrent, and static and dynamic) based on their inherent characteristics. Second, we introduce the concept of perilous field for each hazard and further transform the critical level of the field to its invoked-panic emotion. After that, we propose an emotional contagion model to simulate the evolving process of panic emotion caused by multiple hazards. Finally, we introduce an emotional reciprocal velocity obstacles (RVOs) model to simulate the crowd behaviors by augmenting the traditional RVO model with emotional contagion, which for the first time combines the emotional impact and local avoidance together. Our experimental results demonstrate that the overall approach is robust, can better generate realistic crowds and the panic emotion dynamics in a crowd. Furthermore, it is recommended that our method can be applied to various complex multihazard environments. [ABSTRACT FROM AUTHOR]

Line-commutated converters are extensively used as the interface between ac grids and classic HVDC systems. At the inverter side, commutation failure of switches is one of the most common faults that can pose threats to the system operation. Practical and reliable study of such phenomena relies on accurate and efficient converter models for simulations. Recently, a parametric average-value model (PAVM) has been presented for ac–dc rectifiers, which considers the internal faults of the converter. In this paper, the PAVM methodology is extended to the dc–ac inverter systems, including the commutation failure of switches. The proposed PAVM also augments an automatic fault detection technique to determine the faulty switches. Using comprehensive simulation studies, the developed model is verified to accurately predict the commutation failure of switches and reconstruct the waveforms consistent with the detailed switching models of inverters while being computationally more efficient. The proposed PAVM is envisioned to be an efficient and accurate asset for simulation of HVDC systems and inevitable when faults of switches need to be considered. [ABSTRACT FROM AUTHOR]

Frequency-dependent coupling (FDC) emerges as a new method to introduce the finite-position transmission zeros (TZs) in the synthesis and design of filtering networks. In this paper, several fundamental building blocks with FDCs are introduced and studied. The higher order filters with many TZs can be constructed by cascading these fundamental building blocks. As compared with the conventional coupled-resonator filters with only constant couplings, the inclusion of FDCs can potentially create more TZs with the same coupling topology. It is also shown that to realize the same TZs, a filter can be realized in a simplified structure with less cross-couplings by using FDCs. In this paper, one complete filter design procedure is illustrated, including the steps of the circuit model synthesis by the method introduced in this paper, physical dimensioning of the filter by the electromagnetic simulation and measurement of the fabricated filter. The measurement results are in very good agreement with the theoretical predictions, which validates the modular design strategy for filters with FDCs. [ABSTRACT FROM AUTHOR]

The haze problem in cities poses a great threat to human health. Although there are many factors that cause fog and haze, the main reason is the increase of the PM2.5 concentration. Due to the complexity of the particles motion, it is difficult to use traditional methods obtain information about PM2.5 (including its sources, influencing factors, and distribution forecast). This paper presents a cellular automata (CA) model based on a multivariate regression model and several physical models to analyze the generation and diffusion of PM2.5. In Beijing for example, after the researches, the multiple regression confirmed that the major source of PM2.5 is vehicle pollution, which accounts for 39.2% of the pollution generated in Beijing. The secondary source is from the residential areas, accounting for 27.5% in the winter. Besides, 32% of the total pollution comes from nearby areas. In addition, it is also confirmed that the weather factors, such as, temperature, wind, pressure and relative humidity, and radiation are all have a great impact on PM2.5. The CA model is demonstrated to be an effective simulation and prediction method for PM2.5 since it allows for the estimation of the governance results by simulating the control scheme and predicting the concentration of PM2.5 accurately in the next 48 h. In the prediction experiment, 77.5% of prediction error is less than $20~ {\mu }\text{g} / {\text {m}}^{3}$. [ABSTRACT FROM AUTHOR]

This paper focuses on the problem of maximizing the minimum power gain in a wide main lobe for an array antenna. To obtain the desired power gain pattern, current literatures solve the problem known as shaped beam pattern synthesis (SBPS) by setting the beam pattern expression as the cost function. The power gain in a certain direction of the array antenna is comprehensively decided by the array radiated power density and the total radiated power. Both these two parameters are affected by the selection of array elements’ weights. However, the SBPS-based methods do not take the total radiated power into account. Therefore, the SBPS-based methods cannot obtain the power gain pattern directly, and the optimal power gain pattern, consequently, cannot be guaranteed. To overcome this deficiency, this paper maximizes the minimum power gain in the desired wide main lobe by directly setting the power gain expression as the cost function. Aiming at optimizing the cost function, this paper first sets up a power gain optimization problem which has concave form. Termed this optimization problem as the power gain pattern synthesis (PGPS) problem. The concave PGPS problem is then converted to a series of convex subproblems and an iterative algorithm is proposed to solve it efficiently. Solution to the PGPS problem is proven to be able to achieve higher minimum power gain in a desired wide main lobe than the results from the SBPS-based algorithms. Simulations are carried out with both linear array antenna and planar array antenna. Comparisons with the existed SBPS-based algorithms validate the effectiveness and advantages of the proposed PGPS-based algorithm. In addition, further improvement on suppressing the sidelobe level for the PGPS problem is discussed. [ABSTRACT FROM AUTHOR]

Vehicle platooning systems are often equipped with vehicle-to-vehicle (V2V) communication technologies to improve both the road efficiency and road safety by exchanging vehicle information over wireless networks to maintain relatively small inter-vehicle distance. The road safety often relies on the quality of service delivered by the V2V communication. The V2V networks are, however, subject to channel fading and often have limited communication bandwidth. The limited bandwidth inevitably compromises the road safety as the vehicular network will easily get congested if the number of vehicles joining the network increases. To address the challenges of ensuring vehicle safety under unreliable wireless network with limited bandwidth, this paper first uses a two-state Markov chain to model the channel fading in vehicular networks. Under the Markov chain model, this paper further develops a novel distributed event triggered strategies under which the vehicle platooning system achieves stochastic $\mathcal {L}_2$ string stability while ensuring an efficient use of the limited communication bandwidth. The simulation results are provided to verify the effectiveness and advantages of the proposed methods. [ABSTRACT FROM AUTHOR]

This paper proposes an adaptively scaled belief (ASB) in Gaussian belief propagation (GaBP) designed for use in large multi-user multi-input multi-output (MU-MIMO) detection under higher order modulation schemes. In practical MU-MIMO systems, the dominant factor in the poor convergence of GaBP iterative detection is approximation errors arising from the fact that the law of large numbers does not work well in many such applications as a result of physical system limitations. Unfortunately, the approximation errors become more severe when there is higher correlation among typical bit-wise prior beliefs when higher order quadrature amplitude modulation schemes are used. To cope with the impairments arising from inter-bit correlation, symbol-wise beliefs can be defined for GaBP self-iterative detection, although this still does not remove approximation errors. As a simple method for mitigating the harmful effects of approximation error, this paper proposes a novel method for adaptive belief scaling while stabilizing the dynamics of random MIMO channels. Based on the functionality of ASB, we also propose a method for approximately calculating conditional expectations with lower computational complexity without sacrificing detection capability. Finally, the validity of using ASB for symbol-wise iterative detection in suppressing the bit-error-rate floor level is confirmed. [ABSTRACT FROM AUTHOR]

A residue number system (RNS) has an inherent parallel structure that can be utilized for improving computer hardware systems. An RNS represents large integer numbers as a smaller integer set, or residues of a modulo set, without carry propagation between them. Hence mathematical operations, such as addition or subtraction, can be performed on the residues independently. This paper proposes an RNS implementation of motion estimation for the latest video coding standard known as high-efficiency video coding (HEVC) or H.265. Since motion estimation is the most computationally intensive task in video coding, several simplified algorithms are proposed for mitigating the problem, but the majority of them result in a worsening peak signal-to-noise ratio (PSNR) or bit-rate performance, or sometimes both. This paper also proposes a modified algorithm based on a test-zone (TZ) search algorithm, a widely used fast-search algorithm with good rate-distortion performance, suitable for hardware implementation for encoding ultra-high-definition videos in real time. The results show that worst-case PSNR degradation and bit-rate increases compared with the TZ search in the HEVC reference software implementation are negligible, and the hardware gate count is less than for many other designs in the literature. [ABSTRACT FROM AUTHOR]

Two challenges are combined when compressed tests are computed for path delay faults: 1) path delay faults that are important to detect are associated with long paths, and many of these faults are undetectable and 2) it may not be possible to compress a given test for a path delay fault. This paper addresses these challenges in the context of test data compression methods that are based on a linear-feedback shift-register (LFSR). The basic approach that this paper uses modifies initially random seeds for the LFSR into seeds that produce tests for detecting target faults. This approach can find seeds even if the available tests cannot be compressed into seeds. In addition, the procedure described in this paper also selects detectable path delay faults to address the presence of undetectable path delay faults in the set of target faults. For this purpose it uses a metric that measures the similarity between target and detected path delay faults, and attempts to compute seeds that increase the values of this metric. Experimental results are presented to demonstrate the ability of the procedure to detect path delay faults in benchmark circuits. [ABSTRACT FROM AUTHOR]

Noise power estimation is central to efficient radio resource allocation in modern wireless communication systems. In the literature, there exist many noise power estimation methods that can be classified based on underlying theoretical principle; the most common are spectral averaging, eigenvalues of sample covariance matrix, information theory, and statistical signal analysis. However, how these estimation methods compare against each other in terms of accuracy, stability, and complexity is not well studied, and the focus instead remains on the enhancement of individual methods. In this paper, we adopt a common simulation methodology to perform a detailed performance evaluation of the prominent estimation techniques. The basis of our comparison is the signal-to-noise ratio estimation in the simulated industrial, scientific and medical band transmission, while the reference noise signal is acquired from an industrial production plant using a software-defined radio platform, USRP-2932. In addition, we analyze the impact of different techniques for noise-samples’ separation on the estimation process. As a response to defects in the existing techniques, we propose a novel noise-samples’ separation algorithm based on the adaptation of rank-order filtering. Our analysis shows that the proposed solution, apart from its low complexity, has a very good root-mean-squared error of 0.5 dB and smaller than 0.1-dB resolution, thus achieving a performance comparable with the methods exploiting information theory concepts. [ABSTRACT FROM AUTHOR]

Snow albedo plays an important role in the global climate system. There are notable missing data and error uncertainties in the current remote sensing snow albedo products that are attributed to the limits of remote-sensing technology. Due to the uncertainties of meteorological factors and the differences in various forward model simulation methods, snow albedo forward simulations also have considerable uncertainties. This paper suggests a long-time-series reconstruction of snow albedo utilizing a forward radiation-transferring model and a remote-sensing retrieval model together with multisource remotely sensed data and meteorological data. The key to this paper is to estimate snow information for areas lacking data utilizing a forward model for snow albedo with clear physical mechanisms. The estimated snow information can be used as reliable data for snow albedo reconstructions. The results indicate that the long time series of snow albedo data obtained by coupling the snow albedo retrieval model and forward simulation model is highly accurate. The mean absolute error, root mean square error, Pearson’s correlation coefficient (R), and Nash–Sutcliffe efficiency coefficient of the observed and reconstructed snow albedos are 0.11, 0.14, 0.79, and 0.69, respectively. The reconstructed snow albedo data are underestimated by only 11% relative to the in situ snow surface albedo measurements. In the alpine mountain regions, the proposed method has a simulation accuracy that is 6% greater than that of the MOD10A1 SAD. This paper provides an effective reconstruction solution that improves the accuracy of estimations of snow albedo and fills gaps in the data. [ABSTRACT FROM AUTHOR]

On transmission lines where switching surges are not mitigated with closing resistors and/or surge arresters, high-speed reclosing on a line with trapped charge will produce high overvoltages that have been measured above 3 p.u. Careful simulations of these switching events using available electromagnetic transient (EMT) programs consistently produce significantly higher voltages than the measurements. This indicates a phenomenon present on the line that acts to reduce the switching surge magnitudes but is not typically modeled. This paper aims to identify the required simulation practices in reproducing the field measured overvoltages in EMT simulations and investigates the sensitivity of results to modeling approaches and electrical parameters. Field measurements from a switching surge test of a 230-kV line without surge mitigation have been used for model comparisons. Variations in frequency-dependent line modeling, ground resistivity, skin effect, shunt conductance, parallel lines, and source-side detail have been tested in an unsuccessful attempt to decrease the difference between the field measurements and the higher simulation overvoltages. It is demonstrated that even though the pattern of the transient voltage waveforms can be reproduced very well using frequency-dependent line models, the magnitude of the maximum overvoltage is significantly overestimated unless the effect of corona is considered. Two types of corona models are tested, and both demonstrate that corona is the primary factor that allows the simulations to correctly reproduce high peak overvoltage measurements. [ABSTRACT FROM AUTHOR]

This paper analyzes different models for evaluating investments in energy storage systems (ESS) in power systems with high penetration of renewable energy sources. First of all, two methodologies proposed in the literature are extended to consider ESS investment: a unit commitment model that uses the “system states” (SS) method of representing time; and another one that uses a “representative periods” (RP) method. Besides, this paper proposes two new models that improve the previous ones without a significant increase of computation time. The enhanced models are the “system states reduced frequency matrix” model which addresses short-term energy storage more approximately than the SS method to reduce the number of constraints in the problem, and the “representative periods with transition matrix and cluster indices” (RP-TM&CI) model which guarantees some continuity between representative periods, e.g., days, and introduces long-term storage into a model originally designed only for the short term. All these models are compared using an hourly unit commitment model as benchmark. While both system state models provide an excellent representation of long-term storage, their representation of short-term storage is frequently unrealistic. The RP-TM&CI model, on the other hand, succeeds in approximating both short- and long-term storage, which leads to almost 10 times lower error in storage investment results in comparison to the other models analyzed. [ABSTRACT FROM AUTHOR]

In this paper, a new circuit model is proposed to simulate plasma-induced damage (PID). It includes the two sheaths of the plasma, the blocking capacitor, and the RF power source coupled with the victim device. As a result, this model accounts for both the ac behavior of the plasma and the local voltage imbalance induced by differences in shading factors. The advantage of this approach, compared with the previous works, is that it can yield the waveform impinged by the plasma on the transistor gate, which is known to influence the amount of reliability degradation experienced by the device. Finally, this model is also utilized to elucidate the impact of a parasitic capacitance connected to the transistor gate on the extent of the PID inflicted on the victim device. [ABSTRACT FROM AUTHOR]

Surface acoustic wave sensors find their application in a growing number of fields. This interest stems in particular from their passive nature and the possibility of remote interrogation. Still, the sensor package, due to its size, remains an obstacle for some applications. In this regard, packageless solutions are very promising. This paper describes the potential of the AlN/ZnO/LiNbO3 structure for packageless acoustic wave sensors. This structure, based on the waveguided acoustic wave principle, is studied numerically and experimentally. According to the COMSOL simulations, a wave, whose particle displacement is similar to a Rayleigh wave, is confined within the structure when the AlN film is thick enough. This result is confirmed by comprehensive experimental tests, thus proving the potential of this structure for packageless applications, notably temperature sensing. [ABSTRACT FROM AUTHOR]

This paper proposes an accurate modeling method to inspect the resistance of JFET region in a silicon carbide (SiC) MOSFET in which piecewise linear approximation of doping profile of the p-well is utilized to simplify the calculation process. With depletion width and scatter width both considered, the newly developed model could obtain the JFET resistance more accurately than the conventional models reported. Sentaurus TCAD simulations and experimental studies are performed to verify the accuracy of the proposed model method. Additional nitrogen implantations for the JFET region are also included to further demonstrate the accuracy of the model. The developed model could help analyze the percent of JFET resistance in the total device on-state resistance, thus providing a guideline for the optimization of SiC MOSFETs. [ABSTRACT FROM AUTHOR]