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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]

To analyse the behaviour of marine diesel engines in unsteady states for different purposes, for example to determine the fuel consumption or emissions level, to adjust the control strategy, to manage the maintenance, etc., a goal-based mathematical model that can be easily implemented for simulation is necessary. Such a model usually requires a wide range of operating data, measured on a test stand. This is a time-consuming process with high costs and the relevant data are not available publicly for a selected engine. The present paper delivers a rapid and relatively simple method for preparing a simulation model of a given marine diesel engine, based only on the widely available data in the project guides indicated for steady state conditions. After establishing the framework of the mathematical model, it describes how the parameters of the model can be adjusted for the simulation model and how the results can be verified as well. Conceptually, this is a trial and error method, but the presented case example makes clear how the parameters can be selected to reduce the number of trials and quickly determine the model parameters. The necessary descriptions are given through a case study, which is the MAN-B&W 8S65ME-C8 marine diesel engine. The engine is assumed to be connected to a constant pitch propeller. The presented mathematical model is a mean-value zero-dimensional type with seven state variables. The other variables of the engine are determined based on the state independent variables and the input value, which is the fuel rate. The paper can be used as a guideline to prepare a convenient mathematical model for simulation, with the minimum publicly available data. [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]

The predictive control method deals with the prediction of the motor behavior based on a mathematical model of the motor. This model is dependent on the motor parameters. However, these parameters may not match with their actual values due to the measurement error or they may change during the operation of the motor. All these uncertainties and model inexactitude lead to inaccurate prediction of the motor behavior and deteriorate the performance of the predictive algorithm. This paper presents an extension of the predictive current control (PCC) method to improve the prediction accuracy for a permanent-magnet synchronous motor (PMSM). The proposed strategy not only reduces the current ripple but also improves the robustness of the system against parameter uncertainties. Simulation and experimental results that confirm the good performance of the proposed method are presented. [ABSTRACT FROM PUBLISHER]

The tubeless vortex reducer was used to reduce the pressure drop in a cavity with radial inflow. In previous studies, the mechanism of vortex breakdown in tubeless vortex reducers was not clear, and there was a lack of direct guidance for engineering design. In this paper, we studied the vortex and pressure in the cavity in detail by large-eddy simulation (LES) and experiments. A mathematical model, which has high applicability and compatibility, was established to guide the pre-design of tubeless vortex reducers. The LES results showed that the high-speed and large-scale vortices broke rapidly at the nozzle inlet and reached the minimum size at the nozzle outlet. Furthermore, the enhancement of vortex in the downstream cavity was restrained. When the rotating speed was relatively low, strong negative vortices formed and the pressure drop increased in the downstream cavity. The experiments showed that the nozzle performance directly affected the flow characteristics and pressure drop in the cavity. Compared with the simple cavity, the tubeless vortex reducer generated lower pressure drop. The average relative error between the mathematical model and the experimental results was only 9.3%. [ABSTRACT FROM AUTHOR]

This paper presents the interaction between the overhead transmission lines (OHTLs) and their towers. In this paper, the electric field around the tower of the overhead transmission lines is calculated. The charge simulation method, combined with the image method, is used to develop a model that consists of subconductors of the OHTLs and the tower. The charges on the surface of each subconductor of the overhead transmission lines are simulated by a set of infinite line charges, of various charge densities, along the length of the subconductor, and the induced charges on the surface of the tower are simulated by a set of finite line charges. [ABSTRACT FROM PUBLISHER]

The introduction of communication systems to power system controllers has brought in another layer of complexity in their design and operation. In this paper, a plug-in hybrid electric vehicle charging facility is studied. A linearized model of the facility is built, including both the dc/dc and dc/ac converters of the distributed energy resources. In addition, a control strategy that includes both local and networked loops is proposed to monitor and control the dc bus voltage of a local energy storage unit. This dc bus voltage is crucial to the self-sustaining capabilities of the system. A review of challenges and opportunities in networked control systems is presented, and the impacts of communication factors to the charging facility stability are analyzed. Finally, a real-time simulation platform which combines both electrical and communication networks is presented to validate the small-signal model, control strategy, and stability analysis including the communication effects. [ABSTRACT FROM PUBLISHER]

In this paper, the diagnosis of soft faults in lossy electric transmission lines is studied through the inverse scattering approach, extending a recently reported study on lossless transmission lines. The considered soft faults are modeled as continuous spatial variations of distributed characteristic parameters of transmission lines. The diagnosis of such faults from reflection and transmission coefficients measured at the ends of a line can be formulated as an inverse problem. The relationship between this inverse problem and the inverse scattering theory has been studied by Jaulent in 1982 through transformations from the telegrapher's equations of transmission lines to Zakharov-Shabat equations. The present paper clarifies and completes the computation of the theoretic scattering data required by the inverse scattering transform from the practically measured engineering scattering data. The inverse scattering method is then applied to numerically simulated lossy transmission lines to confirm the feasibility of the studied approach to soft fault diagnosis. [ABSTRACT FROM AUTHOR]

Variable compression ratio (VCR) technology has long been recognized as a method for improving the engine performance, efficiency, and fuel economy of automobiles, with reduced emissions. In this paper, a novel hydraulic continuous VCR system based on the principle of an adjustable hydraulic volume is introduced. The continuous variable compression ratio of the VCR system is realized by the hydraulic system controlling the rotation of the eccentric pin to change the positions of the top dead center (TDC) and the bottom dead center (BDC). The construction of the mathematical model and simulation model of the VCR system is also presented in this paper. The piston motion characteristics, flow characteristics, and pressure characteristics of the hydraulic system of the VCR system at different engine speeds and adjustment quantities are studied by simulation in this paper. The simulation results show that the VCR system has a fast response and good dynamic characteristics, and can achieve continuous adjustment of the compression ratio. [ABSTRACT FROM AUTHOR]

Co-simulation opens new opportunities to combine mature electromagnetic transients (EMT) and phasor-mode (PM) solvers, and takes advantage of their respective high accuracy and execution speed. In this paper, a relaxation approach is presented, iterating between an EMT and a PM solver. This entails interpolating over time the phasors of the PM simulation, extracting phasors from the time evolutions of the EMT simulation, and representing each subsystem with a proper multiport equivalent when simulating the other subsystem. Various equivalents are reviewed and compared in terms of convergence of the PM-EMT iterations. The paper also considers the update with frequency of the Thévenin impedances involved in the EMT simulation, the possibility to compute the EMT solution only once per time step, and the acceleration of convergence through a prediction over time of the boundary variables. Results are presented on a 74-bus, 23-machine test system, split into one EMT and one PM subsystem with several interface buses. [ABSTRACT FROM PUBLISHER]

Establishing causal relations between random variables from observational data is perhaps the most important challenge in today’s science. In remote sensing and geosciences, this is of special relevance to better understand the earth’s system and the complex interactions between the governing processes. In this paper, we focus on an observational causal inference, and thus, we try to estimate the correct direction of causation using a finite set of empirical data. In addition, we focus on the more complex bivariate scenario that requires strong assumptions and no conditional independence tests can be used. In particular, we explore the framework of (nondeterministic) additive noise models, which relies on the principle of independence between the cause and the generating mechanism. A practical algorithmic instantiation of such principle only requires: 1) two regression models in the forward and backward directions and 2) the estimation of statistical independence between the obtained residuals and the observations. The direction leading to more independent residuals is decided to be the cause. We instead propose a criterion that uses the sensitivity (derivative) of the dependence estimator, the sensitivity criterion allows to identify samples most affecting the dependence measure, and hence, the criterion is robust to spurious detections. We illustrate the performance in a collection of 28 geoscience causal inference problems, a database of radiative transfer models simulations and machine learning emulators in vegetation parameter modeling involving 182 problems, and assessing the impact of different regression models in a carbon cycle problem. The criterion achieves the state-of-the-art detection rates in all cases, and it is generally robust to noise sources and distortions. The presented approach confirms the validity in observational bivariate problems in the earth sciences. [ABSTRACT FROM AUTHOR]

Applying the Jiles-Atherton (JA) model to simulate the dynamics of power electronics circuit is a challenge but very attractive since it is possible to carry out continuous simulation with only several input parameters. Although other methods such as the Preisach-model can result in approximate waveforms for such applications, it is still a far distance to reach exact ones to suit chaos and other high accuracy-requiring researches. In this paper, the JA model has been successfully applied to model the dynamics of resonant inverter for driving a nonlinear load: a fluorescent lamp. The circuit is driven by a high frequency square wave voltage source. A semi-theoretical fluorescent lamp model developed from HID lamp model is adopted in the modeling. The simulation waveforms of voltage across the lamp and current through it are close to those measured ones reported in the literature papers. [ABSTRACT FROM AUTHOR]

This paper presents a new solution method that combines state-space and nodal analysis for the simulation of electrical systems. The presented flexible clustering of state-space-described electrical subsystems into a nodal method offers several advantages for the efficient solution of switched networks, nonlinear functions, and for interfacing with nodal model equations. This paper extends the concept of discrete companion branch equivalent of the nodal approach to state-space described systems and enables natural coupling between them. The presented solution method is simultaneous and enables benefitting from the advantages of two different modeling approaches normally exclusive from one another. [ABSTRACT FROM AUTHOR]

Some soft magnetic materials are strongly dependent on the temperature, because of their low Curie temperature. In order to predict their behavior in electrical devices, engineers need hysteresis models able to consider the temperature. This paper is an attempt to consider the temperature in an existing model of static hysteresis through its parameters. Variations of some parameters with temperature are issued or build thanks to the literature. At the end, all needed parameters have an analytical law versus temperature. The simulation results are compared with measurements and discussed. [ABSTRACT FROM AUTHOR]

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Many computational models of visual attention performing well in predicting salient areas of 2D images have been proposed in the literature. The emerging applications of stereoscopic 3D display bring an additional depth of information affecting the human viewing behavior, and require extensions of the efforts made in 2D visual modeling. In this paper, we propose a new computational model of visual attention for stereoscopic 3D still images. Apart from detecting salient areas based on 2D visual features, the proposed model takes depth as an additional visual dimension. The measure of depth saliency is derived from the eye movement data obtained from an eye-tracking experiment using synthetic stimuli. Two different ways of integrating depth information in the modeling of 3D visual attention are then proposed and examined. For the performance evaluation of 3D visual attention models, we have created an eye-tracking database, which contains stereoscopic images of natural content and is publicly available, along with this paper. The proposed model gives a good performance, compared to that of state-of-the-art 2D models on 2D images. The results also suggest that a better performance is obtained when depth information is taken into account through the creation of a depth saliency map, rather than when it is integrated by a weighting method. [ABSTRACT FROM AUTHOR]

This paper deals with the development of a hardware-in-the-loop (HIL) real-time simulation setup for vehicular systems. In modeling a vehicular drivetrain, the battery model poses the greatest challenge. Mathematical battery models suitable for real-time and transient simulation are often inaccurate due to internal electrochemical reactions in the battery and external factors such as loading conditions. To model these phenomena precisely while maintaining low computational intensity as required for real-time simulation is a prohibitively difficult task. In lieu of a mathematical model, this paper presents a simulation setup where actual batteries are interfaced with a real-time simulator. It provides a platform to test the emerging battery technologies for which dependable models may not be readily accessible. Results are presented for an HIL model of a planetary-gear-system hybrid electric vehicle with actual batteries in the loop of the simulation. [ABSTRACT FROM PUBLISHER]

Transient simulation programs, either nodal analysis-based electromagnetic transient program (EMTP-like) or state-variable-based, are used very extensively for modeling and simulation of various power and energy systems with electrical machines. It has been shown in the literature that the method of interfacing machine models with the external electrical network plays an important role in numerical accuracy and computational performance of the overall simulation. This paper considers the state-variable-based simulation packages, and provides a constant-parameter decoupled RL-branch equivalent circuit for interfacing the ac induction and synchronous machine models with the external electrical network. The proposed interfacing circuit is based on the voltage-behind-reactance formulation which has been shown to have advantageous properties. For the synchronous machines, this paper describes both implicit and explicit (approximate) interfacing methods. The presented case studies demonstrate the advantages of using the proposed interfacing method over the traditional qd-models that are conventionally used in many simulation packages. [ABSTRACT FROM AUTHOR]

This paper proposes a model that adequately describes the operation of the transformer at deep saturation, suitable for power-electronics applications, and a method for determining its parameters. Simulation and experimental results are presented to confirm the validity of the model and the method. [ABSTRACT FROM PUBLISHER]

Switched-mode power supplies (SMPS) are becoming an essential part of many electronic systems as the industry drives toward miniaturization and energy efficiency. However, practical SMPS design courses are seldom offered. In this paper, a generalized MATLAB/SIMULINK modeling technique is first presented. A proposed practical SMPS design course at Lunghua University, Taiwan, which incorporates this technique, is then described. In order to validate the correctness of the proposed modeling technique, four prototype SMPS are provided in this paper. These prototype circuits also serve as the laboratory section of the proposed course. The main objective of the course is to teach final-year undergraduate students and first-year Master's students how to design an SMPS in real life. The positive response from students indicates that the proposed technique is useful for SMPS design courses. [ABSTRACT FROM PUBLISHER]

Multiphase (more than three phases) power electronic converters are required mainly for feeding variable-speed multiphase drive systems. This paper presents one such solution by using a direct ac–ac converter that can be used to supply a nine-phase drive system. The input is a fixed-voltage and fixedfrequency three-phase input, and the output is a variable-voltage and variable-frequency nine-phase output. A simple pulsewidthmodulation technique is developed for the proposed ac–ac converter named as a nonsquare three-to-nine-phase matrixconverter configuration. The developed modulation technique is based on the comparison of a high-frequency carrier signal with the duty ratios. Although the carrier-based scheme is widely employed for the control of back-to-back converters, it has recently been used for controlling a three-to-three-phase matrix converter. This concept is extended in this paper for controlling a threeto-nine-phase matrix converter. With the two techniques that are proposed, one outputs 0.75 of the input magnitude and the other outputs reach 0.762 of the input. This is the maximum value of the output voltage in the linear modulation range that can be achieved in this configuration of the matrix converter. The viability of the proposed control techniques is proved analytically through simulation and an experimental approach. [ABSTRACT FROM PUBLISHER]

This paper suggests a pedagogical approach to teaching the subject of behavioral modeling of switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The methodology is oriented toward electrical engineering (EE) students at the undergraduate level, enrolled in courses such as “Power Electronics,” “Industrial Electronics,” or the like. The proposed approach is demonstrated by simulation example of a realistic active power factor corrector (APFC) system. The paper discusses the derivation of PSPICE/ORCAD-compatible behavioral models, their software implementation, and fast time domain, frequency domain, and stability analysis simulation techniques suitable for virtual study of complex nonlinear feedback systems. Some “tricks of the trade” are also suggested. The paper can be helpful to instructors of a “Virtual Power Electronics Laboratory” course wanting to conduct a software experiment on a PFC system. [ABSTRACT FROM AUTHOR]

This paper presents an improved semitheoretical fluorescent lamp model by including the effect of the lamp tube temperature on the lamp electrical parameters at different dimming levels. The experimental results have verified that the lamp tube temperature is a linear function of the lamp's input power and has significant influence on the lamp's electrical parameters during the dimming process. The comparison on the simulation and measurements shows that the improved lamp model can predict the lamp electrical characteristics accurately in a wide dimming range under both low- and high-frequency operations. [ABSTRACT FROM AUTHOR]

This paper presents the evaluation of the performance, in terms of uncertainty, of a tool designed to estimate the main parameters of a model of a photovoltaic panel (PVP) under real and/or simulated working conditions. The presented tool permits the characterization of the panel, and it is useful to predict its behavior in whatever working condition; in this way, it is possible to compare the actual and expected performance to prevent any decrease in the output power, so permitting the replacement of the monitored module before it goes out of order or its efficiency falls under a given threshold. The well-known two-diode model is used to estimate the parameters of the electrical equivalent circuit of the PVP and to simulate the I–V and P–V characteristic curves in any given environmental condition of irradiance and/or temperature. The model and the estimation algorithm are implemented with MATLAB functions, whereas data acquisition and result presentation are managed by a LabVIEW graphics user interface. The presented tool has been validated against an experimentally characterized PVP. The environmental parameters of the model such as irradiance and temperature have been set (with their respective uncertainties) during simulations or directly measured during the outdoor tests, whereas the others parameters have been evaluated using a best-fit algorithm on the measured data. The estimation is based on the minimization of a new objective function and on a modified expression of the model resistances, which differ from those mentioned in the available literature. After a review of the state of the art, this paper provides the description of the estimation technique and its validation by means of simulations and experiments. Some results are also provided to illustrate the performance of the proposed test method. [ABSTRACT FROM AUTHOR]

This paper studies microgrids where loads are supplied by parallel-connected inverters controlled by decentralized active power/voltage frequency and reactive power-/voltage-magnitude droop control laws. A paralleled ac system, such as a multiinverter microgrid, is susceptible to circulating currents due to differences in voltage magnitude, frequency, phase angle, or dc offset. Circulating currents due to differences in voltage magnitude and dc offset have been known issues reported in literature. However, an in-depth analysis of the problem is required to ascertain the deviation of the system-operating condition from the desired condition. This paper provides a mathematical model that predicts the effect of voltage-magnitude offsets on reactive power sharing between inverters. Simulation and experimental results verify the accuracy of the analytical results obtained from the mathematical model. We examine the effect of dc-circulating currents and propose a simple capacitor emulation control law implemented in software to eliminate dc-circulating currents. This solution is a possible alternative for hardware implementation to eliminate dc-circulating currents. The effectiveness of the capacitor emulation control law has been verified through experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, a real-time walking trajectory generation method with three-mass models at constant body height for 3-D biped robots is extended for a diagonal walking. By realization of the diagonal walking, the availability is improved. The modeling of this method is more precise than that of conventional real-time walking trajectory generation methods. In this method, the zero-moment point equation of a body is derived, and an analytic solution of a body trajectory at a constant body height in a single support phase is obtained. Because the analytic solution is used, real-time trajectory generation can be realized. In addition, this method has advantages of the body trajectory at the constant body height. The validities are confirmed from simulations of the 2-D walking and an experiment of the 3-D diagonal walking. [ABSTRACT FROM AUTHOR]

This paper presents an online procedure for the automatic search of the maximum-torque-per-ampere operating region for a synchronous reluctance motor. The algorithm is based on a signal-injection method with a random-based perturbation pattern applied to a common direct-torque-controlled drive. Among motor parameters, only the stator resistance is required to perform the automatic procedure. Simulations and experimental results are presented in the paper, demonstrating the benefits of the proposed algorithm. The solution is easily extended to any ac drive. [ABSTRACT FROM PUBLISHER]

This paper presents a finite-element-based simulation methodology to improve on multiscale modeling and analysis limitations of power electronics development. The method utilizes homogenization and nonmatching grid concepts to offer a high degree of flexibility and reduce computational effort. The applied homogenization method provides effective material properties to realize full-chip modeling performance without the need to model geometric details. The concept of nonmatching grids allows the inclusion of a subregion with substantially finer mesh than its surrounding regions. This allows the flexible integration of micrometer scale geometries with a high degree of detail within the full-chip model. Both concepts are thoroughly introduced and an application to a state-of-the-art power electronics semiconductor technology is presented. This paper focuses on electrothermal interaction and is experimentally verified on a dedicated test structure. The presented results provide electrothermal insights in current power electronic technologies and emphasize their potential to further improve the robustness and reliability of next generation technologies. [ABSTRACT FROM PUBLISHER]

A simplified pulse width modulation (PWM) strategy for a neutral-point-clamped three-level converter with unbalanced dc links is proposed in this paper to achieve high-quality line-to-line output voltages and to maximize the linear modulation range. The simplified strategy takes the direct output voltage modulation by calculating the special solutions of the voltage–second balance equations without detecting the position of the reference vector in the asymmetrical and complicated space voltage vector diagrams to reduce the calculation time. A novel solution based on the state transition is proposed to extend the maximum linear modulation index to 1.15. Furthermore, the asymmetric control of the split dc link by the proposed PWM is implemented by adjusting the special solutions. The difference between the conventional space vector PWM and the proposed strategy is conducted to illustrate the advantages of the simplified strategy. The effectiveness of the proposed modulation strategy is verified by simulation and experiment results. [ABSTRACT FROM PUBLISHER]

This paper presents a novel oversampling deadbeat current control approach for permanent magnet synchronous motor drives capable of operating at a controller sampling frequency multiple of the power converter switching frequency. Model-based controllers suffer from heavy computational demand and performance degradation due to parameter uncertainties. The proposed controller concurrently with field-programmable gate array implementation permits to achieve a constant switching frequency and an optimal current ripple along with a high current-loop bandwidth and robust behavior to parameter variation. A disturbance observer has been added to the proposed controller in order to compensate for the converter voltage distortions. The proposed control strategy is tested through both simulations and experiments. [ABSTRACT FROM AUTHOR]

Compressed sensing (CS) based radar imaging requires the use of a mathematical model of the observation process. Inaccuracies in the observation model may cause defocusing in the reconstructed images. In the observation process, the observation positions are usually not known perfectly. Imperfect knowledge of the observation positions is a major source of model errors in imaging. In this paper, a method is proposed to compensate the observation position errors in CS-based radar imaging. Instead of treating the observation-position-induced model errors as phase errors in the data, the proposed method can determine the observation position errors as part of the imaging process. It uses an iterative algorithm, which cycles through steps of target reconstruction and observation position error estimation and compensation. The proposed method can estimate the observation position errors accurately, and the reconstruction quality of the target images can be improved significantly. Simulation results and experimental results from rail-mounted radar and airborne synthetic aperture radar are presented to show the effectiveness of the proposed method. [ABSTRACT FROM PUBLISHER]

This paper presents an electric circuit-based battery and a capacity fade model suitable for electric vehicles (EVs) in vehicle-to-grid applications. The circuit parameters of the battery model (BM) are extracted using genetic algorithm-based optimization method. A control algorithm has been developed for the battery, which calculates the processed energy, charge or discharge rate, and state of charge limits of the battery in order to satisfy the future requirements of EVs. A complete capacity fade analysis has been carried out to quantify the capacity loss with respect to processed energy and cycling. The BM is tested by simulation and its characteristics such as charge and discharge voltage, available and stored energy, battery power, and its capacity loss are extracted. The propriety of the proposed model is validated by superimposing the results with four typical manufacturers’ data. The battery profiles of different manufacturers’ like EIG, Sony, Panasonic, and Sanyo have been taken and their characteristics are compared with proposed models. The obtained battery characteristics are in close agreement with the measured (manufacturers’ catalogue) characteristics. [ABSTRACT FROM PUBLISHER]

3-D hybrid finite-element (FE) boundary integral equation (BIE) formulations are widely used because of their ability to simulate large inhomogeneous structures in both open and bounded simulation domains by applying each method where it is the most efficient. However, some formulations suffer from breakdown frequencies at which the solution is not uniquely defined and errors are introduced due to internal resonances. In this paper, we investigate the occurrence of spurious solutions resulting from these resonances by using the concept of the Poincaré–Steklov or Dirichlet-to-Neumann operator, which provides a relation between the tangential electric field and the electric current on the boundary of a domain. By identifying this operator in both the FE and BIE method, several new properties of internal resonances in 3-D hybrid FE-BIE formulations are easily derived. Several conformal and nonconformal formulations are studied and the theory is then applied to a scattering problem. [ABSTRACT FROM AUTHOR]

The paper deals with the developing of the methodological backgrounds for the modeling and simulation of complex dynamical objects. Such backgrounds allow us to perform coordinate transformation and formulate the algorithm of its usage for transforming the serial mathematical model into parallel ones. This algorithm is based on partial fraction decomposition of the transfer function of a dynamic object. Usage of proposed algorithms is one of the ways to decrease calculation time and improve PC usage while a simulation is being performed. We prove our approach by considering the example of modeling and simulating of fourth order dynamical object with various eigenvalues. This example shows that developed parallel model is stable, well-convergent, and high-accuracy model. There is no defined any calculation errors between well-known serial model and proposed parallel one. Nevertheless, the proposed approach's usage allows us to reduce calculation time by more than 20% by using several CPU's cores while calculations are being performed. [ABSTRACT FROM AUTHOR]

Road traffic simulation is a useful tool for studying road traffic and evaluating solutions to traffic problems. Large-scale agent-based road traffic simulation is computationally intensive, which triggers the need for conducting parallel simulation. This paper deals with the synchronization problem in parallel agent-based road traffic simulation to reduce the overall simulation execution time. We aim to reduce synchronization operations by introducing some redundant computation to the simulation. There is a trade-off between the benefit of reduced synchronization operations and the overhead of redundant computation. The challenge is to minimize the total overhead of redundant computation and synchronization. First, to determine the amount of redundant computation, we proposed a way to define extended layers of partitions in the road network. The sizes of extended layers are determined by the behavior of agents and the topology of road networks. Second, due to the dynamic nature of road traffic, a heuristic was proposed to adjust the amount of redundant computation according to traffic conditions during simulation run-time to minimize the overall simulation execution time. The efficiency of the proposed method was investigated in a parallel agent-based road traffic simulator using real-world network and trip data. Results have shown that the method can reduce synchronization overhead and improve the overall performance of the parallel simulation significantly. [ABSTRACT FROM PUBLISHER]

Using mathematical models of physiological systems in medicine has allowed for the development of diagnostic, treatment, and medical educational tools. However, their complexity restricts, in most cases, their application for predictive, preventive, and personalized purposes. Although there are strategies that reduce the complexity of applying models based on fitting techniques, most of them are focused on a single instant of time, neglecting the effect of the system's temporal evolution. The objective of this research was to introduce a dynamic fitting strategy for physiological models with an extensive array of parameters and a constrained amount of experimental data. The proposed strategy focused on obtaining better predictions based on the temporal trends in the system's parameters and being capable of predicting future states. The study utilized a cardiorespiratory model as a case study. Experimental data from a longitudinal study of healthy adult subjects undergoing aerobic exercise were used for fitting and validation. The model predictions obtained in a steady state using the proposed strategy and the traditional single-fit approach were compared. The most successful outcomes were primarily linked to the proposed strategy, exhibiting better overall results regarding accuracy and behavior than the traditional population fitting approach at a single instant in time. The results evidenced the usefulness of the dynamic fitting strategy, highlighting its use for predictive, preventive, and personalized applications. [ABSTRACT FROM AUTHOR]

This paper presents a multiphysics simulation and layout design technique for complementary metal–oxide–semiconductor–microelectromechanical systems (MEMS) (CMOS-MEMS) based on an electrical circuit simulator. An equivalent circuit model for the mechanical equation of motion has been translated into a Verilog-A-compatible hardware description language (HDL) in the Cadence Virtuoso environment to attain new designing capabilities such as automatic mask-layout synthesis, design rule check, and layout-versus-schematic verification for MEMS structures. Microelectromechanical components such as parallel-plate actuator and bending suspension, whose analytical equation models are already known, are also interpreted into HDL-coded equivalent circuits. Behavior of a MEMS device, including the electrostatic displacement hysteresis and the negative spring constant effect, is numerically simulated as a lumped mass-and-spring system, which has been verified to quantitatively agree with that of the corresponding analytical simulation results. A multiphysics model for the Colpitts oscillator circuit has been built in the developed simulation environment by replacing a quartz resonator with a compact model of an electrostatic silicon resonator, and its self-excited resonance has been confirmed by the simulation after the coordination of the device and circuit parameters. A prototype conversion tool for MEMS parameterized cell has also been developed to demonstrate automatic generation of mask layouts for a silicon resonator, which has been cross-checked against the experimental measurements to verify the simulation accuracy.\hfill[2012-0365] [ABSTRACT FROM AUTHOR]

In this paper, the balance control of a ball and beam system is considered. Based on the T-S fuzzy modeling, the dynamic model of the ball and beam system is formulated as a strict feedback form with modeling errors. Then, an adaptive dynamic surface control (DSC) is utilized to achieve the goal of ball positioning subject to parameter uncertainties. The robust stability of the closed-loop system is preserved by using the Lyapunov theorem. In addition to simulation results, the proposed T-S fuzzy model-based adaptive dynamic surface controller is applied to a real ball and beam system for practical evaluations. Simulation and experimental results illustrate that the proposed control scheme has much better performance than that of conventional DSC. Furthermore, parameter uncertainties and external disturbance are considered to highlight the robustness of the proposed control scheme. [ABSTRACT FROM PUBLISHER]

The tandem rolling of hot metal strip is a highly complex and nonlinear process which presents a difficult control challenge. The control of the threading phase of this process is particularly difficult as the model of the process changes significantly and rapidly as the head of the strip is sequenced from stand to stand during threading. Moreover, to improve the quality of the final product during threading, it is necessary to reduce excursions in the strip tension, looper position, and strip thickness. In this paper, we present a comprehensive model of the threading process plus the results of our initial work to develop a suitable controller which handles the rapid changes in the model during threading. The success of our initial work is demonstrated by simulations. [ABSTRACT FROM PUBLISHER]

Periodic circuits driven by multitone signals are still a challenging simulation problem despite several numerical methods being presented in the literature. In this paper, a mixed time–frequency method for the solution of this problem and suitable for both autonomous and nonautonomous circuits is presented. The method is based on an extension of the envelope following method, which allows us to reduce the number of unknowns involved in the steady-state problem with respect to previous mixed time–frequency approaches, and a suitable reformulation of the periodicity constraint that allows us to obtain a significant acceleration in the determination of the solution by reducing the time interval along which the envelope analysis must be performed. The method is first presented for nonautonomous circuits and then extended to autonomous ones. [ABSTRACT FROM AUTHOR]

In this paper, we present an accurate and computationally efficient model for circuit simulation of ultrathin-body silicon-on-insulator MOSFETs with strong back-gate control. This work advances previous works in terms of numerical accuracy, computational efficiency, and behavior of the higher order derivatives of the drain current. We propose a consistent analytical solution for the calculation of front- and back-gate surface potentials and inversion charge. The accuracy of our surface potential calculation is on the order of nanovolts. The drain current model includes velocity saturation, channel-length modulation, mobility degradation, quantum confinement effect, drain-induced barrier lowering, and self-heating effect. The model has correct behavior for derivatives of the drain current and shows an excellent agreement with experimental data for long- and short-channel devices with 8-nm-thin silicon body and 10-nm-thin BOX. [ABSTRACT FROM AUTHOR]

The modular multilevel converter (MMC) is one of the most potential converter topologies for high-power/voltage systems, specifically for high-voltage direct current (HVDC). One of the main technical challenges of an MMC is to eliminate/minimize the circulating currents of converter arms while the capacitor voltages are maintained balanced. This paper proposes a model predictive control (MPC) strategy that takes the advantage of a cost function minimization technique to eliminate the circulating currents and carry out the voltage balancing task of an MMC-based back-to-back HVDC system. A discrete-time mathematical model of the system is derived and a predictive model corresponding to the discrete-time model is developed. The predictive model is used to select the best switching states of each MMC unit based on evaluation and minimization a defined cost function associated with the control objectives of MMC units and the overall HVDC system. The proposed predictive control strategy: 1) enables control of real and reactive power of the HVDC system; 2) achieves capacitor voltage balancing of the MMC units; and 3) mitigates the circulating currents of the MMC units. Performance of the proposed MPC-based strategy for a five-level back-to-back MMC-HVDC is evaluated based on time-domain simulation studies in the PSCAD/EMTDC software environment. The reported study results demonstrate a satisfactory response of the MMC-HVDC station operating based on the proposed MPC strategy, under various conditions. [ABSTRACT FROM AUTHOR]

In this paper, issues related to parameter identification and high-performance control of the drive system with an elastic joint are discussed. After a brief introduction, the mathematical model of the drive and the proposed high-performance control structure are presented. The effect of the location of closed-loop poles and cancellation of zeros of the structure is examined. Then, the mathematical models of the Kalman filters used in this study are presented, and the results of the identification procedure are described. The effectiveness of the proposed structure has been examined under simulation and experimental study. [ABSTRACT FROM PUBLISHER]

Total variation (TV) has been used as a popular and effective image prior model in regularization-based image processing fields, such as denoising, deblurring, super-resolution (SR), and others, because of its ability to preserve edges. However, as the TV model favors a piecewise constant solution, the processing results in the flat regions of the image being poor, and it cannot automatically balance the processing strength between different spatial property regions in the image. In this paper, we propose a spatially weighted TV image SR algorithm, in which the spatial information distributed in different image regions is added to constrain the SR process. A newly proposed and effective spatial information indicator called difference curvature is used to identify the spatial property of each pixel, and a weighted parameter determined by the difference curvature information is added to constrain the regularization strength of the TV regularization at each pixel. Meanwhile, a majorization–minimization algorithm is used to optimize the proposed spatially weighted TV SR model. Finally, a significant amount of simulated and real data experimental results show that the proposed spatially weighted TV SR algorithm not only efficiently reduces the “artifacts” produced with a TV model in fat regions of the image, but also preserves the edge information, and the reconstruction results are less sensitive to the regularization parameters than the TV model, because of the consideration of the spatial information constraint. [ABSTRACT FROM AUTHOR]

This is the first part of a two-paper series and presents the modeling methodology for all of the main components of a typical wind power plant for power system transient studies. The models developed are intended for investigation of the temporary overvoltages, switching overvoltages, and lightning overvoltages. The component models developed include the high-frequency models of the vacuum and SF6 circuit breakers, three core cables for the collector grid, and quad core cables for the wind turbine tower, turbine transformer, doubly fed asynchronous generator, and surge arrester. The models developed are wideband in nature and can be used for all studies, except the transformer model which requires two variations for the low–mid frequency range and mid–high frequency range. Detailed user-defined models developed for both vacuum and SF6 circuit breakers take account of the restrikes, reignitions, prestrikes, low-frequency high-current interruption, and high-frequency low-current interruption. The generator and transformer transient models include a representation of the various high-frequency capacitive couplings. The success criteria for each individual component model are discussed, and the model performance is validated against these criteria. [ABSTRACT FROM AUTHOR]

This paper treats the problems of the particle-in-cell (PIC) models at higher pressures. We discuss the influence of the time discretization on the results of a model of a highly collisional plasma using a simplified analytical model. A new algorithm is proposed that calculates the collisions independently of the simulation time step, thus eliminating the errors introduced by the time discretization. The benchmarks at the pressure of the neutral gas of 665 Pa show that the presented algorithm is approximately seven times faster than a classical PIC model with the same accuracy. [ABSTRACT FROM AUTHOR]

Many probabilistic maintenance models developed for maintenance scheduling and optimization are based on state diagrams. Classical maintenance models based on state diagrams provide inaccurate results when inspection rates are nonperiodic. An attempt has been made to rectify some modeling properties through the use of an alternative graph; however, it requires Monte Carlo simulation to accurately calculate reliability. This paper highlights an idealistic property of classical state diagrams and proposes new state diagrams to correct it. The accuracy of Markov models based on proposed state diagrams is verified through a theoretical discussion. Significant differences between the results given by classical and proposed maintenance models are shown through a numerical example for imperfect maintenance. The behavior of mean time between failures is also analyzed to validate the proposed models. With the proposed model, reliability analysis of different maintenance activities can be calculated analytically without the use of Monte Carlo simulation. [ABSTRACT FROM PUBLISHER]

This paper presents an electromagnetic interference (EMI) model to evaluate the conducted common mode (CM) disturbances produced by matrix converters (MCs). The model is based on obtaining a high frequency (HF) equivalent circuit with HF sources representing the switching devices. The circuit resolution in the frequency domain allows the calculation of any EMI parameter with very low computational burden and avoids convergence problems, which are common in time domain methods. The original contribution lies in the source model implementation and placement. The simulation and experimental results for CM leakage currents validate the EMI model. [ABSTRACT FROM PUBLISHER]