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Ovarian cancer is among the seven most common types of cancer in women, being the most fatal gynecological tumor, due to the difficulty of detection in early stages. Aptamers are important tools to improve tumor diagnosis through the recognition of specific molecules produced by tumors. Here, aptamers and their potential targets in ovarian cancer cells were analyzed by in silico approaches. Specific aptamers were selected by the Cell-SELEX method using Caov-3 and OvCar-3 cells. The five most frequent aptamers obtained from the last round of selection were computationally modeled. The potential targets for those aptamers in cells were proposed by analyzing proteomic data available for the Caov-3 and OvCar-3 cell lines. Overexpressed proteins for each cell were characterized as to their three-dimensional model, cell location, and electrostatic potential. As a result, four specific aptamers for ovarian tumors were selected: AptaC2, AptaC4, AptaO1, and AptaO2. Potential targets were identified for each aptamer through Molecular Docking, and the best complexes were AptaC2-FXYD3, AptaC4-ALPP, AptaO1-TSPAN15, and AptaO2-TSPAN15. In addition, AptaC2 and AptaO1 could detect different stages and subtypes of ovarian cancer tissue samples. The application of this technology makes it possible to propose new molecular biomarkers for the differential diagnosis of epithelial ovarian cancer. [ABSTRACT FROM AUTHOR]

Developing simulation models for electromagnetic field problems often deals with approximations of the full set of Maxwell’s equations, to obtain performant methods. This is also the case for the so-called Darwin model, which has the capability of including resistive, inductive, and capacitive effects without the need of solving full-wave Maxwell’s equations. However, an issue is the difficulty of prescribing realistic excitations of the model, e.g., via a terminal voltage. In this article, the straightforward prescription of the scalar potential on electric ports is investigated via Poynting’s theorem, with the outcome that it can be considered as physical voltage excitation up to frequencies, where the validity of the Darwin model itself is lost. [ABSTRACT FROM AUTHOR]

With the maturity of CMOS technologies and their use in low-voltage analog applications, the accuracy of SPICE models is very important. Here, an extremely accurate yet simple form of the charge-sheet model is developed using a symmetric polynomial interpolation of the charge in the channel. This formulation of the drain current retains the same simplicity of the industry-standard surface potential MOSFET models based on the symmetric linearization method (SLM). But, unlike the SLM, it is developed without requiring the linearization of the charge in the channel, hence, the asymmetries and the nonlinearity are accurately accounted for. The model, although more accurate, has the same computational efficiency and easy implementation of the SLM. Finally, the equations of the currents and terminal charges can be worked out to have the same mathematical form as the SLM. [ABSTRACT FROM AUTHOR]

Recent long term planning studies have demonstrated the important role of variable renewables (VRE) in decarbonising our energy system. However, cost-optimising models do not capture the visual impact of VREs on the landscape which can act to undermine their public acceptability. Here, we use crowd-sourced scenicness data to derive spatially explicit wind energy capacity potentials for three scenarios of public sensitivity to this visual impact. We then use these scenarios in a cost-optimising model of Great Britain's power system to assess their impact on the cost and design of the electricity system in 2050. Our results show that total system costs can increase by up to 14.2% when public sensitivity to visual impact is high compared to low. It is thus essential for policy makers to consider these cost implications and to find mechanisms to ameliorate the visual impact of onshore wind in local communities. [ABSTRACT FROM AUTHOR]

The launch of synchronous induction coilgun (SICG) is always accompanied by strong thermal and structural effects, which will cause serious damage to the structure of the armature, and multiphysics computation is an effective means to avoid this problem. Compared with the conventional circuit-based model, the finite-element analysis (FEA) is more suitable for the multiphysics computation of SICG, but it is also more time-consuming. In this article, the implicit function and level set (IFLS) method is introduced to rapidly simulate the multiphysics problem of SIGC based on FEA. The armature is modeled implicitly in the material domain and the position of it is updated through the implicit function, avoiding the moving mesh and remesh problems in the arbitrary Lagrangian–Eulerian (ALE) method, which is generally used to dealing with the dynamic mesh problem. Besides, the volume loss density and the Lorentz force per unit in the moving band are transformed back to the initial position to complete the coupling of the thermal and structural field and maintain the accuracy and continuousness of the simulation. A single-stage SICG model is established with the ALE and IFLS methods, and the results show that the computation time of the IFLS method is nearly halved. Finally, the IFLS method is applied to the simulation of multistage SICG, and the computational efficiency is greatly improved. [ABSTRACT FROM AUTHOR]

Electrochemical mechanisms in lithium-ion batteries (LIBs) pose a significant challenge in deriving models that are highly accurate, have low computational complexity, and enable real-time state and parameter estimation. In this article, we propose a machine learning model as an important building block of a physics-based ANCF-e model that was recently proposed for LIBs. This machine learning model is used to estimate nonlinear potentials, including the open-circuit potential, electrolyte potential, and lithium-intercalation overpotential. Such an estimation is shown to result in a much smaller computational complexity and therefore can enable real-time state and parameter estimation. Three different machine learning architectures are explored, including multilayer perceptron, radial basis function (RBF)-based neural networks, and support vector machines. The training of these machine learning models is carried out using current profiles obtained with an electric vehicle model from driving cycles as inputs and ANCF-e model-based outputs. The underlying ANCF-e model is validated both through a high-fidelity numerical approach, including COMSOL and an experimental test using commercial LIBs. Both validations are carried out under both constant current discharging and dynamic load cycles. The resulting performance using these machine learning models is compared using different metrics, including estimation errors, convergence rates, training time, and computational time. The results indicate that an RBF-based neural network leads to better estimation of the underlying potentials in LIBs and that all machine learning models require a computational time that is 95% smaller than a physics-based approach for this estimation. [ABSTRACT FROM AUTHOR]

In this work, a physics-based compact model for channel charges and drain current in nanosheet FETs is presented. The model follows the bottom-up approach. The channel charges are calculated using the 1-D density of states (DOS), which seamlessly scales up for devices with 2-D or 3-D DOS as the confinement reduces in a particular direction. The model uses full Fermi–Dirac (FD) statistics and requires only two additional fitting parameters. The accuracy of the model is confirmed by comparing it with data from in-house 2-D coupled Poisson–Schrödinger (PS) solver and Technology Computer Aided Tool (TCAD) simulations. The proposed model accurately predicts the subband energies, inversion charges, channel potential, and drain current for nanosheet FETs (NsFETs) with different dimensions and applied biases. [ABSTRACT FROM AUTHOR]

This article presents a compact quantum threshold voltage (${V}_{\text {th}}$) shift model for a junctionless (JL) quadruple-gate (QG) FET in subthreshold region. Starting from our previous compact model for JL QG FET, the potential and the classical electron density are calculated. Considering 2-D quantum confinement, four types of quantum systems are modeled as a combination of quantum harmonic oscillator (QHO) and quantum well with bottom perturbation potential, depending on the device dimensions. Electron subband energy level for each quantum system is analytically derived to get quantum electron density. The quantum ${V}_{\text {th}}$ shift model is obtained by the ratio of quantum and classical electron line density. The modeling results are validated by 3-D numerical device simulation. It is shown that the proposed model can accurately capture the quantum ${V}_{\text {th}}$ shift in JL QG FET where both fin width and height are 3 nm. Therefore, the proposed ${V}_{\text {th}}$ shift model can be used for quantum corrections for circuit simulation of JL QG FETs. [ABSTRACT FROM AUTHOR]

In order to accelerate the semiconductor device simulation, we propose to use a neural network to learn an approximate solution for desired bias conditions. With an initial solution (predicted by a trained neural network) sufficiently close to the final one, the computational cost to calculate several unnecessary solutions is significantly reduced. Specifically, a convolutional neural network for the metal–oxide–semiconductor field-effect transistor (MOSFET) is trained in a supervised manner to compute the initial solution. In particular, we propose to consider a device template for various devices and a compact expression of the solution based on the electrostatic potential. We empirically show that the proposed method accelerates the simulation significantly. [ABSTRACT FROM AUTHOR]

Thepermissible external field strength described in international exposure guidelines and standards was derived under the assumption that humans are exposed to a uniform field in free space. However, realistic field distributions are partial body exposure to the nonuniform field. Thus, the permissible field strength has overconservative values when applying the spatial peak strength to practical compliance assessment. In this study, we discuss the relationship between the uniform external magnetic field strength and induced electric field in different body part models to help set the permissible field strength for nonuniform magnetic field exposure. We proposed a formula for estimating induced electric field from the electromotive force of cuboid models based on Faraday's law. Then, we applied the formula to homogeneous ellipsoidal and homogeneous realistically shaped models. Furthermore, we investigated the effect of model inhomogeneity to confirm the difference in the induced electric field in anatomical body models. The homogeneous ellipsoidal model was comparable to the homogeneous realistically shaped model, whereas the model inhomogeneity led to an approximately 1.5 times increase in the computed maximum electric field strength. [ABSTRACT FROM AUTHOR]

Power electronic (PE) penetration in energy networks has been increasing rapidly in recent years due to the campaign to rely on distributed generation as a clean, sustainable energy source. This increase leads to new challenges and stability problems occurring because of the increase in the harmonic current injected into the power network. To study and address such issues, accurate and computationally efficient models are required. In this article, a Hammerstein–Wiener-based approach is proposed to develop black-box models for PE devices capable of capturing the devices’ harmonic characteristics. A novel method based on magnitude square coherence is also proposed to compare the results of different models in the frequency domain. The method is implemented in a simulation environment and was further tested and validated through laboratory measurements. [ABSTRACT FROM AUTHOR]

Safe and effective exploitation of lithium ion (Li-ion) batteries requires advanced battery management systems. This article proposes a computationally efficient, control-oriented model of a Li-ion cell. The model describes the spatial nature of both the chemical species and temperature dynamics in a computationally efficient way. The method takes advantage of the algebraic structure that arises from the distributed nature of the model. We show that, by discretizing the model partial differential equations with a finite difference method, the coupling equations take a semiseparable structure for which an efficient algebra exists. This approach yields an efficient modeling tool that can be employed to design model-based estimation and control algorithms. The proposed model is validated against a high order computational fluid dynamics model showing accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Devices fabricated from soft magnetic composites (SMCs) are gaining popularity in research and application. The multiscale characteristics require special attention. Solving the quasi-statics Maxwell’s equations on such devices consumes huge time and memory if the granular scale of SMCs is resolved. We have proposed a localized orthogonal decomposition (LOD) homogenization strategy, which allows us to compute the problem on a middle scale while retrieving the material dimension. The LOD projector has a localization property so that it can be accurately approximated on a local patch. In this work, we explore the localization characteristic further to show that the projector can be reused at different time steps. The requirement for computational time and memory can be greatly reduced. A numerical example in two dimensions is provided to show the feasibility and advantage of this approach. This technique is applied to a domain of SMCs with randomly distributed polygon-shaped granules. Finally, error analysis is provided to show the validation of the LOD projector. [ABSTRACT FROM AUTHOR]

A physically-based model of the Buried Multiple Junction (BMJ) detector has been established with consideration of the device operation in reach-through (RT) conditions. In such a condition, the breakdown voltage of one junction can shift depending on its adjacent junction’s bias voltage. The modeling approach consists in detecting RT conditions, determining depletion limits, electrostatic potential barrier height and thermionic emission current. It allows computations of the detector’s dark currents and spectral responses to monochromatic light illumination. Computations of the detector’s static characteristics have been compared with TCAD simulations and they are in good agreement, which is a model validation. The proposed model explains and determines the detector’s breakdown voltage shift behavior, as well as its changes of spectral responses depending on bias voltages. [ABSTRACT FROM AUTHOR]

One of the most accurate approaches to the lightning-related transient analysis of grounding systems in layered soil is based on the method of moments solution of the integral form of the Maxwell equations. The practical application of this rigorous model to large systems is hindered by a great amount of computer time required for the numerical integration of oscillatory and slowly convergent Sommerfeld integrals (SI). As a result, approximate methods that avoid the solution of SI, e.g., image theory-based methods, are often used for computation of the response of large grounding systems. In this article, we extend the application of the rigorous model for large grounding systems in multilayered soil by applying a procedure that minimizes the number of direct computations of the SI using interpolation over a grid of a small number of sample points. We implement a three-dimensional interpolation scheme that adapts to the problem to minimize the interpolation grid, maintaining the accuracy of the rigorous approach. The developed model is applied for the analysis of transient voltages that might couple to secondary cables and disrupt the operation of connected equipment in case of lightning. The analysis shows that there are cases when the image theory-based models might underestimate the possibly harmful transient voltages. [ABSTRACT FROM AUTHOR]

The modular multilevel converter (MMC) is a popular topology in medium- and high-voltage applications, and many efforts have been spent on MMC modeling. However, the impact of submodule voltage sensor noise (SVSN), which becomes more severe due to increasing switching speed of power semiconductors and compact submodule design, has not been considered in conventional models. In this letter, the SVSN is introduced by coupling capacitances between the sensor and power stage in an MMC switching model. Furthermore, the SVSN impact is considered in an MMC average model based on derivation of the relationship between the SVSN and the duty cycle. The proposed MMC switching model and average model considering the SVSN are validated by comparing simulations with experimental results in an MMC prototype using 10-kV SiC MOSFETS. [ABSTRACT FROM AUTHOR]

A large population in the world has been infected by COVID-19. Understanding the mechanisms of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) is important for the management and treatment of COVID-19. When it comes to the infection process, one of the most important proteins in SARS-CoV-2 is the spike (S) protein, which is able to bind to human Angiotensin-Converting Enzyme 2 (ACE2) and initializes the entry of the host cell. In this study, we implemented multiscale computational approaches to study the electrostatic features of the interfaces of the SARS-CoV-2 S protein receptor binding domain and ACE2. The simulations and analyses were performed on high-performance computing resources in the Texas Advanced Computing Center. Our study identified key residues on SARS-CoV-2, which can be used as targets for future drug design. The results shed light on future drug design and therapeutic targets for COVID-19. [ABSTRACT FROM AUTHOR]

In this article, we present an appropriate compact model of spacer (SP) region for static characteristics of 3-D NAND flash memories. Though many studies on 3-D NAND flash have focused on the intrinsic part, they have not considered analysis on the SP region with gate-surrounded structure which is inevitable for 3-D NAND flash string due to punch-and-plug process. We focus on the electrostatics on the SP region of the 3-D NAND flash and suggest a concept of bias ratio (BR) which can evaluate the average influence of fringing electric field on the parasitic part for efficient implantation to the compact model. First, we introduce the modeling method of the SP region and then verify our modeling results by comparing channel potential using 3-D technology computer-aided design (TCAD) simulation. We also investigate the BR dependences on various device dimensions, and the dependences are comparable with the trends of outer-fringing capacitance. Finally, we demonstrate that our compact model can be efficiently applied to circuit simulation for various bias conditions and varying dimensions such as tapered channel structure, without the necessity of additional parameter extractions for each dimension. [ABSTRACT FROM AUTHOR]

In this article, we discuss numerical aspects related to the accuracy and the computational efficiency of numerical dosimetric simulations, performed in the context of human exposure to static inductive charging systems of electric vehicles. Two alternative numerical methods based on electric vector potential and electric scalar potential formulations, respectively, are here considered for the electric field computation in highly detailed anatomical human models. The results obtained by the numerical implementation of both approaches are discussed in terms of compliance assessment with ICNIRP guidelines limits for human exposure to electromagnetic fields. In particular, different strategies for smoothing localized unphysical outliers are compared, including novel techniques based on statistical considerations. The outlier removal is particularly relevant when comparison with basic restrictions is required to define the safety of electromagnetic fields exposure. The analysis demonstrates that it is not possible to derive general conclusions about the most robust method for dosimetric solutions. Nevertheless, the combined use of both formulations, together with the use of an algorithm for outliers removal based on a statistical approach, allows to determine final results to be compared with reference limits with a significant level of reliability. [ABSTRACT FROM AUTHOR]

Among the emerging technologies that are intended to outperform the current CMOS technology, the field-coupled nanocomputing (FCN) paradigm is one of the most promising. The molecular quantum-dot cellular automata (MQCA) has been proposed as possible FCN implementation for the expected very high device density and possible room temperature operations. The digital computation is performed via electrostatic interactions among nearby molecular cells, without the need for charge transport, extremely reducing the power dissipation. Due to the lack of mature analysis and design methods, especially from an electronics standpoint, few attempts have been made to study the behavior of logic circuits based on real molecules, and this reduces the design capability. In this article, we propose a novel algorithm, named self-consistent electrostatic potential algorithm (SCERPA), dedicated to the analysis of molecular FCN circuits. The algorithm evaluates the interaction among all molecules in the system using an iterative procedure. It exploits two optimizations modes named Interaction Radius and Active Region which reduce the computational cost of the evaluation, enabling SCERPA to support the simulation of complex molecular FCN circuits and to characterize consequentially the technology potentials. The proposed algorithm fulfills the need for modeling the molecular structures as electronic devices and provides important quantitative results to analyze the information propagation, motivating and supporting further research regarding molecular FCN circuits and eventual prototype fabrication. [ABSTRACT FROM AUTHOR]

Induced voltages on overhead distribution lines owing to lightning return strokes cause insulators flashovers and consequently, line outages. Basically, shield wires and surge arresters form the lightning protection system for overhead lines to improve the performance of distribution systems against return strokes. The effectiveness of the lightning protection system depends essentially on the grounding system on which shield wire and surge arrester are installed. This article presents a numerical approach to consider the transient models at the points of discontinuity where the lightning protection system exists on multiconductor overhead line. The finite-difference time-domain method is applied to Agrawal coupling model to solve numerically the electromagnetic wave propagation along the line, whereas the Newton–Raphson method is exclusively used for the points of discontinuity. The results obtained considering the transient model as well as a dc model are compared to clarify the influence of the line discontinuity model on the propagating electromagnetic waves. The computational stability of the proposed method is confirmed for different cases of lightning waveforms, distances between points of discontinuity, and stroke locations with line discontinuities. [ABSTRACT FROM AUTHOR]

This paper presents a general formulation of the generalized multiconductor transmission line (GMTL) method to model a parallel cable harness including straight and bent wires. The parallel cable harness here indicates the uniform cross-sectional wire distribution. The GMTL equations are solved recursively based on the perturbation theory. This GMTL method facilitates an accurate evaluation of the current distributed on a cable harness. On top of that, the current obtained in a radiation problem is decomposed into two traveling currents, i.e., the positive-going and the negative-going currents, based on the least-squares method. With the decomposed currents, the steepest descent method is further adopted to achieve a fast approximation of the total radiated power. Finally, the capability and the limitations of the GMTL method in terms of the electrical wire separation and length are investigated. The necessity of the recursive corrections is also studied. [ABSTRACT FROM AUTHOR]

A new compact model framework is presented to predict the read disturbance induced by hot-carrier injection (HCI) in 3-D NAND flash memory. The physical phenomena that occur during read operation such as band-to-band tunneling (BTBT), impact ionization (II), and HCI, are analyzed through computer-aided design (TCAD) simulation, and the correlations between each other are considered in the compact model. In particular, it is found that a negative feedback process occurs to HCI during read operation due to the geometrical characteristics of 3-D NAND flash. Owing to this phenomenon, time dynamic behavior of HCI is observed during the read operation. The proposed compact model framework includes all of these 3-D NAND flash features. It would help to predict HCI-induced read disturbance without many read measurements. [ABSTRACT FROM AUTHOR]

A conventional input-voltage sensor-based vector-controlled PWM rectifier is used in wide range of applications due to its well-known control structure, simple design, and good dynamic performance. Many existing input voltage sensorless methods have a control structure significantly different from that of conventional vector control, involving additional computational and design efforts. This article proposes a simplified input voltage sensorless control which has the same control structure as that of vector control and can utilize similar controller design procedure. The input voltage required for a phase-locked loop (PLL) is estimated from the current controller output using a simple algebraic equation. The sensorless PLL, so obtained, is mathematically modeled, and its frequency response is shown to be similar to that of a sensor-based PLL. The performance of the proposed method is compared with those of existing methods in terms of input power factor, response to distorted input voltage, sensitivity to system parameter, and computation time requirement through simulations and experiments. Apart from having the lowest computation requirement, the proposed method is shown to achieve the sensorless operation without any performance degradation, compared to the sensor-based operation, and with robustness to parameter variation. The proposed method includes a start-up procedure, which ensures low starting transient current. [ABSTRACT FROM AUTHOR]

Silicon offers an attractive material platform for hardware realization of quantum computing. In this study, a microscopic stochastic simulation method is developed to model the effect of random interface charge traps in silicon metal-oxide-semiconductor (MOS) quantum gates. The statistical results show that by using a fast two-qubit gate in isotopically purified silicon, the two-qubit silicon-based quantum gates have the fidelity >98% with a probability of 75% for the state-of-the-art MOS interface quality. By using a composite gate pulse, the fidelity can be further improved to >99.5% with the 75% probability. The variations between the quantum gate devices, however, are largely due to the small number of traps per device. The results highlight the importance of variability consideration due to random charge traps and potential to improve fidelity in silicon-based quantum computing. [ABSTRACT FROM AUTHOR]

The paper comprises a new systematic approach to determine the critical ambient field needed for positive streamer propagation in nonuniform field gaps. It is shown that such critical streamer penetration field is a function of the basic value previously established for uniform field gaps and the degree of ambient field nonuniformity. The latter quantity is defined by the ratio of the maximum to mean ambient electric fields along the streamer propagation path, which can be determined either analytically or by charge simulation. Such functional dependence of the critical streamer penetration gradient on field nonuniformity has been determined for different rod topologies of rod-plane gap as well as for single and bundle conductor plane gaps. The model is used to determine critical streamer penetration fields and streamer lengths under different impulse voltage levels for different gap configurations and for a tall ground structure exposed to ambient impulse field. The findings of this method are compared to available experimental results and the agreement is found satisfactory. [ABSTRACT FROM AUTHOR]

This letter describes how to evaluate a previously derived full-wave scattering center model directly in time domain. The direct time-domain evaluation is particularly important in the case of moving targets, where the time dependency of the radar cross section (RCS) prevents the efficient usage of the scattering center model in frequency domain. The time-domain formulation generates the scattered signal directly in baseband. [ABSTRACT FROM AUTHOR]

This paper emphasizes the importance of including unbalanced distribution systems for voltage stability studies in power systems. The paper aims to: discuss the various simulation methods for power system analysis; highlight the need for modeling unbalanced distribution system for accurate load margin assessment; demonstrate the influence of net-load unbalance (NLU) on voltage stability margin (VSM). We also share a T&D co-simulation interface with commercial power system solvers. The distribution system is evolving rapidly with high proliferation of distributed energy resources (DERs); these are not guaranteed to proliferate in a balanced manner and uncertainty resulting due to these DERs is well acknowledged. These uncertainties cannot be captured or visualized without representing the distribution system in detail along with the transmission system. We show the impact of proliferation of DERs in various 3-phase proportions on voltage stability margin through T&D co-simulation. We also study the impact of volt/VAR control on voltage stability margin. This analysis is only possible by representing the distribution system in detail through T&D co-simulation. Higher percentage of net-load unbalance (NLU) in distribution system aggravates the voltage stability margin of the distribution system, which can further negatively influence the overall voltage stability margin of the system. [ABSTRACT FROM AUTHOR]

We propose a hierarchical distributed algorithm to solve optimal power flow (OPF) problems that aim at dispatching controllable distributed energy resources (DERs) for voltage regulation at minimum cost. The proposed algorithm features unprecedented scalability to large multi-phase distribution networks by jointly exploring the tree/subtrees structure of a large radial distribution network and the structure of the linearized distribution power flow (LinDistFlow) model to derive a hierarchical, distributed implementation of the primal-dual gradient algorithm that solves OPF. The proposed implementation significantly reduces the computation loads compared to the centrally coordinated implementation of the same primal-dual algorithm without compromising optimality. Numerical results on a 4,521-node test feeder show that the designed algorithm achieves more than 10-fold acceleration in the speed of convergence compared to the centrally coordinated primal-dual algorithm through reducing and distributing computational loads. [ABSTRACT FROM AUTHOR]

Smoothly clamping the drain–source voltage to its saturated value is a common technique used in compact modeling of transistors, such as MOSFETs, JFETs, and HEMTs. The most widely used approach, based on the power function, is not C∞. This article proposes general formulas to construct C∞ clamping functions. Specifically, a new square root form is proposed, which is better than the existing methods and other forms in terms of derivatives and computational efficiency. The new clamping function is verified in the PSP model. It improves both the Gummel symmetry and the harmonic balance simulation. [ABSTRACT FROM AUTHOR]

This paper investigates the in-depth mechanism of commutation failure for a line-commuted converter-based high-voltage direct current (LCC-HVDC) system. The commutation failure prevention control (CFPREV) and the initial fault voltage angle (IFVA) are considered from the view of the voltage-time area (VTA) in the analysis. It is revealed that the IFVA is among the dominant factors for commutation failures when the voltage drop of the inverter bus is relatively small, and CFPREV further intensifies the impact of the IFVA on commutation failures, while the fluctuation of the direct current plays a dominant role in commutation failures under a greater voltage reduction at the inverter bus. A quantitative division of the severity of AC faults is proposed to determine dominant factors for commutation failures. The relationship between the chance of commutation failures to occur and the IFVA is built, and the method used for computing probability of commutation failures is proposed. The influence of the dynamic of CFPREV output on our research is studied. Simulations based on a typical monopole LCC-HVDC system using PSCAD/EMTDC software are conducted to verify the correctness of the theoretic analysis and the effectiveness of the proposed computing methods. [ABSTRACT FROM AUTHOR]

Stalling of residential air conditioners (RACs) following a transient fault can delay the voltage recovery ranging from 3 to 20 seconds. This phenomenon is referred to as fault-induced delayed voltage recovery (FIDVR). Several aggregated RAC models have been presented to replicate the actual FIDVR events. However, they usually have two main drawbacks as: i) considering independent stalling voltage and stalling time for all RACs, ii) resulting in only two ultimate modes; either 100% stalled or 100% normal running. This paper amends the abovementioned shortcomings by proposing a simple and effective performance-based RAC model. The proposed model utilizes a simple explicit relation between the stalling voltage and its required time to stall the RAC, furthermore, it can stall a fraction of RACs based on the voltage dip characteristics. The experimental results support the proposed model and computer simulations employing the IEEE 118-bus test system and Iran's electricity grid reveal the effectiveness of the proposed model. [ABSTRACT FROM AUTHOR]

Voltage model observer is a simple and economical technique for flux estimation in induction motor sensorless drives. However, it shows poor performance in low-speed regions. Therefore, in most cases, the use of this observer is limited. On the other hand, using a simple but accurate estimator is important when the control method is sophisticated and requires heavy computation. This issue will be important in predictive control more than the other methods because the accuracy of the prediction is dependent on the flux estimation. In this paper, a modified closed-loop technique based on voltage model observer is proposed for flux estimation. The feedback loop is supported by the proposed model reference adaptive system direct flux magnitude estimation technique. The dependence of the feedback loop on the stator resistance is eliminated. Therefore, the drift error will be avoided. This will allow the method to withstand the high stator resistance error even at low speeds. Also, a new Lyapunov-based technique for the stator resistance estimation via reduced-order model is proposed. By using the proposed observer, the predictive direct voltage control technique is used as the control method in order to achieve a control method that requires low computation. The proposed method is validated through the experimental results. [ABSTRACT FROM AUTHOR]

Tangible user interface for touch screens, where interaction happens through tangible objects placed on the screen, is one possible option for addressing the lack of haptic feedback in touch screens. For the development of tangible user interface for mutual capacitance touch screens, it is of interest to be able to model how a tangible on the screen surface is seen by the touch screen controller. Finite Element Method simulations for this case is very demanding in terms of both computational resources and time. In this article, we present a computationally efficient model for simulating the capacitance image of arbitrarily shaped conductive sheets on full size mutual capacitance touch screen panels, with calculation time in the order of milliseconds. Output data from the model show good agreement with corresponding measurement data from experiments, with a root mean square deviation of 1.5% of the peak to peak of the measured values for the modeled screen area. [ABSTRACT FROM AUTHOR]

Permissible field strengths in the international guidelines/standard for human protection are derived from peripheral nerve system stimulation at the intermediate frequencies where electrostimulation (attributable to axon activation) is more dominant than thermal effect. Recently, multiscale computation has been used to investigate neuron stimulation thresholds by incorporating individual neurons into realistic head models. However, the consistency of excitation models and permissible levels to specific target tissues (central nervous system) needs to be clarified. This article aims to investigate brain cortical stimulation thresholds using a multiscale computational approach for different scenarios of magnetic field exposures. The magnetic exposures include transcranial magnetic stimulation, uniform exposure, and wireless power transfer systems. Our results confirmed the consistency of the multiscale computations of the cortical thresholds between two independent groups for electromagnetic exposure of transcranial magnetic stimulation (thresholds in the range of motor cortex activation). We also quantified the conservativeness of permissible field strengths of international guidelines/standards at intermediate frequencies. Finally, with the multiscale approach, we confirmed that 10 000 kW of transmitting power of wireless power transfer (WPT) in an electric vehicle charging system may not induce an adverse effect for cortical activation. [ABSTRACT FROM AUTHOR]

In this article, an analytical predictive model of interface charge traps in symmetric, long-channel double-gate, junctionless transistors (JLTs) is proposed based on a charge-based model. Interface charge traps arising from exposure to chemicals, high-energy ionizing radiation, or aging mechanism could degrade the charge–voltage characteristics. The model is predictive in a range of temperatures from 77 to 400 K. The validity of the approach is confirmed by extensive comparisons with numerical technology computer-aided design (TCAD) simulations in all regions of operation from deep depletion to accumulation and from linear to saturation. [ABSTRACT FROM AUTHOR]

In this article, we present a transposable three-transistor static random access memory (3T-SRAM) array consisting of independent double-gate feedback field-effect transistors as binary synaptic devices and access transistors. The synaptic functions of the ${2} \times {2}$ SRAM array are investigated through mixed-mode technology computer-aided design simulations. This 3T-SRAM array provides parallel and bidirectional synaptic updates with fast operating speed. Furthermore, a simplified spike-timing-dependent plasticity learning rule is implemented by adjusting the widths of memory pulses. A compact cell area and a low-leakage power consumption allow this 3T-SRAM array to be used for adaptive synaptic devices in a large-scale neuromorphic system. [ABSTRACT FROM AUTHOR]

Variability in power generation at multiple consumer-owned renewable energy sources can cause random voltage fluctuations, which may result in voltage violations at multiple nodes in a power distribution system. Traditional methods of voltage control are ineffective to address fast voltage variations. New dynamic methods of voltage control using end-user devices can significantly benefit from the knowledge of the dominant influencer of voltage fluctuation (DIVF). This paper introduces information theoretic metrics to identify DIVF for every node in the power distribution system. A node can be DIVF due to its location in the distribution system and its capacity to generate and change its power. Use of traditional power flow algorithms to identify the DIVF is computationally complex, which limits their use in real-time applications. In this paper, information theoretic indicators of the DIVF are computed analytically in a computationally efficient manner, and their effectiveness to identify the DIVF is tested using the IEEE 69 node test system. From simulations, it is shown that differential entropy, Kullback–Leibler distance, and Frechet distance are effective indicators of the DIVF and can successfully identify the most influential nodes providing the foundation for intelligent voltage control. [ABSTRACT FROM AUTHOR]

This paper discusses the impulse analysis of horizontal ground electrode buried in uniform and two-layer soils, describing applications of a recently developed model based on transmission line approach for the analysis of high frequency and transient behavior of grounding systems. Simulations were carried out to compute the ground electrode’ potential and the impulse impedance. A practical method to estimate the effective length of horizontal ground electrodes is presented. The results have been successfully compared with those computed using formulas reported in the literature and only developed for uniform soils. The proposed method is intended for estimation of the effective length of horizontal electrodes buried in soils having a two-layer stratification, which has not yet been considered so far. Based on this method, parametric analysis carried out has shown that the parameters influencing the effective length are mainly the soil resistivity and the rise time of the injected current for uniform soils or associated with the upper layer depth and the refection factor for two-layer soils. Using a genetic algorithm, mathematical expressions for the effective length of horizontal ground electrodes are proposed in terms of these parameters. [ABSTRACT FROM AUTHOR]

This paper presents a continuous control set model-predictive control with a receding horizon for a three-phase voltage-source inverter with an LCL filter. In this proposal, a reduced model of the converter with an embedded integrator and a Kalman filter are used to obtain the inverter-side currents without oscillation. Then, a cost function makes use of these currents to generate the optimum duty cycles for the space vector modulator. With the proposed method, active damping performances, a zero state error, and a reduction of the computational burden are achieved. Compared to the finite control set model-predictive control, the proposed method operates with a fixed switching frequency. Simulations and experimental results show that this proposal works correctly even in the case of grid harmonics and voltage sags. [ABSTRACT FROM AUTHOR]

In many parts of the world, access to basic electricity services remains a significant challenge. The status quo mode of electrification is central grid extension; however, in many areas, off-grid (OG) technologies like minigrids (MGs) and standalone (SA) systems are more suitable for promoting electricity access under cost constraints. Unfortunately, these opportunities are often overlooked due to the complexities of electrification planning, especially for large areas. Researchers have designed technoeconomic planning tools that can be scaled to cut through aspects of this complexity and be fit to address different places and contexts. This paper describes a computer-based optimization model—named the reference electrification model (REM)—which performs automatic electrification planning and is able to identify lowest cost system designs to most effectively provide desired levels of electricity access to populations of any given size. In doing so, REM determines the most suitable modes of electrification for each individual consumer by specifying whether customers should be electrified via grid extension, OG MGs, or SA systems. For each system, REM supplies detailed technical designs at the individual customer level. We have used this model in real planning activities in sub-Saharan Africa and South Asia. The description of REM’s capabilities is supported by case examples. REM stands apart from other electrification planning models because of its high granularity and its capability to provide concrete plans for a wide range of geographical scales. Because of these benefits, REM has the potential to help rationalize electrification planning and expedite progress toward universal electricity access worldwide. [ABSTRACT FROM AUTHOR]

Near-threshold voltage (NTV) digital VLSI circuits, though important, have their sequential elements vulnerable to soft errors. The critical charge for a single event upset for a D-latch depends on its fan-out load, supply voltage, and transistor level parameters. A SPICE simulation-based estimation of the critical charge is highly resource/time intensive. In this paper, we propose a physics-based semianalytical model to estimate the critical charge of a static D-latch as a function of its fan-out load, supply voltage, temperature, and transistor levels parameters. It can, therefore, be used while considering process voltage temperature (PVT) variations. The critical charge estimated by the model is in good agreement with SPECTER simulations with a maximum error of less than 3.4% employing STMicroelectronics 65-nm process design kit (PDK). We also validated the model at 32-nm technology node using technology computer-aided design (TCAD) mixed-mode simulations (a maximum error of less than 7.5% is observed). Using this model, we devise a methodology to estimate the critical charge using a few dc simulations and a single transient SPICE simulation for a given PDK. This is an end-to-end method to include an accurate estimation of the critical charge for latches in NTV standard cell library characterization. [ABSTRACT FROM AUTHOR]

An analytical drain current model is presented for the double-gate monolayer transition metal dichalcogenide (TMD) tunneling FET. The potential in the channel is obtained by applying Gauss’s law to the channel region. Based on Kane’s band-to-band tunneling model, analytical expressions for the tunneling generation rate and drain current are derived by using the tangent line approximation method, which could provide accurate results without any fitting parameters and improve the computational efficiency. The effects of device parameters on the potential profile and transfer characteristics are investigated. The accuracy of the proposed model is verified by comparing with the simulation tool. [ABSTRACT FROM AUTHOR]

The modular multilevel converter (MMC) has attracted extensive research in recent years. An appropriate model is necessary to analyze stability or to design MMC controllers. Several published MMC models have been derived in single-phase form to simplify the modeling mathematics. However, little attention is given to the zero-sequence voltage, which introduces coupling in the single-phase model and leads to significant error. In this paper, after revealing the mechanism behind the zero-sequence voltage, a more accurate generalized single-phase MMC model is proposed, which eliminates the zero-sequence voltage coupling effect and is linearized based on harmonic state space (HSS) theory to precisely characterize the internal harmonic features of MMC. A systematic HSS modeling process is presented for both open-loop and closed-loop conditions. And the proposed model is generalized as it can incorporate different control strategy by controller transfer function substitution. Hence it is valuable to analyze MMC stability and dynamics. Model effectiveness is verified by simulation results. [ABSTRACT FROM AUTHOR]

In this letter, we integrated a floating bottom gate (BG) as a light shielding layer in a thin-film transistor (TFT). We observed abnormal ${I}_{D}$ – ${V}_{D}$ output characteristics and unsaturated current characteristics. In addition, drain-induced barrier lowering has a significant impact on ${I}_{D}$ – ${V}_{D}$ characteristics as the drain voltage increases. These phenomena are due to changes in electrical potential that occur due to the capacitive coupling effect. Technology computer aided design simulations explained and correlated well with our observations. Then, a physical model is proposed to verify the abnormal electrical characteristics. Grounding the BG light shield was found to provide better control over the threshold voltage and total current performance. This letter results may lead to better applications in the TFT driving circuits. [ABSTRACT FROM AUTHOR]

Accurate estimation of power capacity is critical to ensure battery safety margins and optimize energy utilization. Power capacity estimators based on online identified equivalent circuit model have been widely investigated due to the high accuracy and affordable computing cost. However, the impact of noise corruption which is common in practice on such estimators has never been investigated. This paper scrutinizes the effect of noises on model identification, state of charge (SOC) and power capacity estimation. An online model identification method based on adaptive forgetting recursive total least squares (AF-RTLS) is proposed to compensate the noise effect and attenuate the identification bias of model parameters. A Luenberger observer is further used in combination with the AF-RTLS to estimate the SOC in real time. Leveraging the estimated model parameters and SOC, a multiconstraint analytical method is proposed to online estimate the power capacity. Simulation and experimental results verify that the proposed method is superior in terms of estimation accuracy and the robustness to noise corruption. [ABSTRACT FROM AUTHOR]

The hysteresis behavior of piezoelectric actuators is primarily responsible for the decrease of the precision and performance of the nanopositioning systems. To compensate for hysteresis, an inverse model is proposed in this paper as a segment similarity feedforward compensator. Furthermore, the inverse model is improved by using an adaptive method to eliminate the accumulated error of the similarity compensator. The proposed adaptive similarity compensator has the advantages of simple structure, less storage space, and fast calculation speed, and it is available for most engineering situations. Experiments are carried out with the proposed similarity compensator and adaptive similarity compensator. The experimental results show that the compensator can achieve good results and better performance, especially for high-frequency excitations. [ABSTRACT FROM AUTHOR]

Radiation-induced single event transients (SETs) are expected to evolve to single event multiple transients (SEMTs) due to the downscaling of transistor feature size, which also increases the difficulty of the vulnerability estimation for large-scale digital integrated circuits. In this paper, a novel layout-based soft error vulnerability estimation approach which is termed LBSEVEA is proposed to evaluate the impact of heavy ions on the vulnerability of combinational circuits. The physical process of interaction between particles and devices, especially nuclear reaction and scattering process are included in the LBSEVEA. In addition, ambipolar diffusion and bipolar amplification effect, which induce additional charge collection of the adjacent transistors and the hitting transistor, are also considered. A new method calculating the collected charge induced by the bipolar amplification effect is presented. By introducing the layout information of the target circuits into the identification of the adjacent cells, SEMTs effect can be considered in the vulnerability estimation. A fast SPICE simulation tool is adopted to conduct the fault injected netlist simulations, which can make a favorable compromise between the consumption of computer resources and simulation precision. Furthermore, induced soft error numbers, distributions of charge collected by the hitting nodes and the adjacent nodes, and SET pulse width distributions are presented. Besides, heatmaps of induced pulse widths for the layout of two benchmark circuits are provided. Finally, the constraints, the flexibility, and the scalability of the LBSEVEA are discussed. The ability to estimate the impact of process variations on the vulnerability is also presented. Compared with simulation and experimental results, the LBSEVEA can fairly estimate the vulnerability of combinational circuits. [ABSTRACT FROM AUTHOR]

Permanent magnet (PM) synchronous machines (PMSMs) with concentrated windings (CW) exhibit high content of space harmonics leading to non–sinusoidal distribution of PM flux linkage and phase inductances in addition to the non-sinusoidal wave shape of the induced electromotive force. The ideal single reference frame-based PMSM model considers these parameters to be sinusoidal and does not include the effect of harmonics. Hence, computation of electromagnetic torque using ideal model can lead to deviation from the actual waveform. In this paper, a novel analytical model for electromagnetic torque has been derived using multiple reference frames (MRF) incorporating non-sinusoidal aspects of CW PMSM. Initially, the PM flux linkage and inductances in abc frame are extended by incorporating higher order harmonics. Then, the extended model is transformed into dq–axis using MRF rotating at speeds of dominant harmonics in PM flux linkages and inductances, the fundamental being the electrical rotor frequency. Based on this MRF model, a comprehensive electromagnetic torque model for the CW PMSM is derived. Simulation and experiments are conducted on a CW PMSM to validate the proposed model under different operating conditions. [ABSTRACT FROM AUTHOR]