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

This paper proposes an analytical threshold voltage model for the dielectric pocket double gate (DP-DG) junctionless FETs (JLFETs). The channel potential function has been obtained by solving 2-D Poisson’s equation using an evanescent mode analysis with suitable boundary conditions. The potential function has then been used for modeling the threshold voltage to investigate the effects of the DP thickness and length on the short-channel effects of the structure. The effects of source and drain depletion regions have been included for improving the accuracy of the model. The model results of DP-DG JLFETs have been compared with the simulation data obtained from the 2-D TCAD ATLAS device simulator. [ABSTRACT FROM AUTHOR]

The field-plate (FP) technique suppresses the electric field crowding at the p-n junction by inducing the interface charges in the drift region. However, due to the modeling difficulty, the physical meaning cannot be elaborated via the conventional 2-D methods, not to mention the designing optimization. Therefore, the FP assistant reduced surface field effective concentration profile (ECP) is proposed in this paper to explore the physical insight of the FP assistant 2-D coupling. The ECP simplifies the sophisticated 2-D coupling by equating the FP assistant effect to the variation of the ECP. As a result, a simple and effective 1-D analytical model is presented to qualitatively and quantitatively explore the FP-induced surface field reshaping and its distinctive breakdown mechanism. The analytical solutions are found out to be consistent with the simulation results obtained from MEDICI, a commercial TCAD tool. [ABSTRACT FROM AUTHOR]

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]

The layout-induced cylindrical breakdown may occur as a result of the multifinger or circular layout-induced 3-D curvature effect resulting in the breakdown voltage reduction of the power device significantly. In this paper, by using effective doping concentration (EDC) concept, the inherent 3-D problem is simplified as a 1-D problem. Based on the EDC concept, a 1-D analytical model is presented to qualitatively and quantitatively explore the impact of curvature effect on the breakdown mechanism of SOI lateral double diffused MOS. The analytical solutions are found out to be consistent with the simulation results well obtained from MEDICI, a commercial technology computer-aided design tool. To the best of our knowledge, the proposed model is the first 1-D model which can accurately describe the 3-D curvature effect. [ABSTRACT FROM AUTHOR]

This paper proposes a dynamic model with iron saturation to obtain better dynamic performance and more accurately steady-state performance than the dynamic model without iron saturation for the dual-stator brushless doubly-fed induction generator. Based on the proposed dynamic model, the MATLAB/SIMULINK model is established. The key to the simulation model considering iron saturation is that the magnetizing inductance can be updated for each simulation cycle. The magnetizing inductance used in the simulation is experimentally measured to guarantee the simulation accuracy. Dynamic simulations including the current, voltage, flux linkage, active power, and torque are performed, showing that the dynamic model considering iron saturation contributes to the merits of reducing the setting time and the oscillation amplitudes of the torque and the power in starting stage. Experimental assessment is carried out to verify the effectiveness of the theoretical analysis. [ABSTRACT FROM AUTHOR]

To understand the spatial deployment of base stations (BSs) is the first step to analyze the performance of cellular networks and further design efficient networking protocols. Poisson point process (PPP), which has been widely adopted to characterize the deployment of BSs and established the reputation to give tractable results in the stochastic geometry analyses, usually assumes a static BS deployment density in homogeneous PPP (HPPP) models or delicately designed location-dependent density functions in in-homogeneous PPP models. However, the simultaneous existence of attractiveness and repulsiveness among BSs practically deployed in a large-scale area defies such an assumption, and the $\alpha $ -stable distribution, one kind of heavy-tailed distributions, has recently demonstrated superior accuracy to statistically model the varying BS density in different areas. In this paper, we start with these new findings and investigate the intrinsic feature (i.e., the spatial self-similarity) embedded in the BSs. Afterwards, we refer to a generalized PPP setup with $\alpha $ -stable distributed density and theoretically derive the related coverage probability. In particular, we give an upper bound of the derived coverage probability for high signal-to-interference-plus-noise ratio thresholds and show the monotonically decreasing property of this bound with respect to the variance of BS density. Besides, we prove that our model could reduce to the single-tier HPPP for some special cases and demonstrate the superior accuracy of the $\alpha $ -stable model to approach the real environment. [ABSTRACT FROM AUTHOR]

Ultrasonic guided waves are widely used in industrial nondestructive testing for pipes and plates, where pipe waves and plate waves exhibit similar behaviors for some specific modes. This paper investigates the characteristics of an SH0 mode plate wave converted to a T(0, 1) mode pipe wave based on their similar dispersion and wave structure properties. First, the analytical solution is initially proposed to analyze the characteristics of the SH0-wave propagation in a model of arrayed plates coupled to a pipe. The dispersion curves of the shear horizontal waves are established in a bounded double-layer plate in which the effect of the material and the effect of the thickness ratio of the layers are both considered. An equivalent model of a T-shaped plate wrapped around a pipe is then presented, and the numerical simulation of the SH0-wave propagation in the T-shaped plate is studied. Finally, the validity of the model is verified by experiments in which the periodic permanent magnet (PPM) electromagnet acoustic transducer (EMAT) to generate the SH0-wave, and the arrayed PPM EMAT to detect the T(0, 1)-wave are designed and built. [ABSTRACT FROM AUTHOR]

In this paper, an analytic model is proposed, which provides, in a continuous manner, the current–voltage ( $I$ – $V$ ) characteristic of high-performance tunneling FETs (TFETs) based on direct bandgap semiconductors. The model provides the closed-form expressions for $I$ – $V$ based on: 1) a modified version of the well-known Fowler–Nordheim (FN) formula (in the ON-state) and 2) an equation that describes the OFF-state performance while providing continuity at the ON/OFF threshold by means of a term introduced as the continuity factor. It is shown that the traditional approaches, such as FN, are accurate in TFETs only through correct evaluation of the total band bending distance and the tunneling effective mass. General expressions for these two key parameters are provided. Moreover, it is demonstrated that the tunneling effective mass captures both the ellipticity of evanescent states and the dual (electron/hole) behavior of the tunneling carriers, and it is further shown that such a concept is even applicable to semiconductors with nontrivial energy dispersion. Ultimately, it is found that the $I$ – $V$ characteristics obtained by using this model are in close agreement with the state-of-the-art quantum transport simulations both in the ON- and OFF-state, thus providing the validation of the analytic approach. [ABSTRACT FROM PUBLISHER]

Mid-infrared atmospheric absorption bands centered at 4.3 \mu\mboxm are applied in target detection. Image simulation, as an important tool for the adaption and optimization of a sensor, ought to be conducted for the development of instruments using this spectral range. In this paper, a top-of-atmosphere (TOA) image simulation method is proposed, and this method is tested on two bands of the sensor SPIRIT III (band S1: 4.21–4.37 \mu\mboxm, S2: 4.23–4.47 \mu\mboxm). Band translation models are established for the generation of surface emissivity images, and an analytic radiative transfer model is modified and utilized to simulate TOA radiance fast and accurately. Accuracy analysis of the proposed method shows relative errors of within $\pm$6% and $\pm$1% in simulated surface emissivity and TOA radiance, respectively. Moreover, image simulation is often used for band selection in the sensor design stage. To illustrate how our proposed simulation method was applied in band selection, we used simulated TOA radiance of bands S1 and S2 as an example and compared their possibility of false alarms caused by high-temperature objects. Experimental results show that high-temperature objects are more unlikely to become false alarms on band-S1 images. Therefore, the spectral range of S1 is a better option for target detection application than S2. This TOA simulation method can be also applied in band selection among other 4.3- \mu\mboxm absorption bandwidths, as was done in this paper. [ABSTRACT FROM AUTHOR]

In spite of the wide improvement in computer simulation packages, analyzing, and optimizing the simulation model, particularly under uncertainty can still be computationally expensive and time-consuming. This paper aims to tackle these features by proposing a comprehensive methodology applied to black-box stochastic simulation models under uncertainty. For this purpose, the common surrogate model as Kriging metamodel is served to fit the simulation input–output data produced by Latin hypercube sampling experimental design. Taguchi terminology of robust design enables the optimization methods to control uncertainty and uncontrollable environmental factors. So as to formulate robust counterpart optimization, three different models in the class of dual-response surface are integrated with metamodel and robust design. Leave-one-out cross-validation is applied to validate the Kriging metamodel. Finally, a numerical case study as a direct speed control of dc motor under uncertainty is served to demonstrate the applicability of the proposed method in real engineering problems. This simplified and practical mechatronics case illustrates how the proposed procedure can be expanded for analyzing and optimizing the real complex systems. [ABSTRACT FROM AUTHOR]

This paper reports on a novel simulation method combining the speed of analytical evaluation with the accuracy of finite-element analysis (FEA). This method is known as the rapid analytical-FEA technique (RAFT). The ability of the RAFT to accurately predict frequency response orders of magnitude faster than conventional simulation methods while providing deeper insights into device design not possible with other types of analysis is detailed. Simulation results from the RAFT across wide bandwidths are compared to measured results of resonators fabricated with various materials, frequencies, and topologies with good agreement. These include resonators targeting beam extension, disk flexure, and Lamé beam modes. An example scaling analysis is presented and other applications enabled are discussed as well. The supplemental material includes example code for implementation in ANSYS, although any commonly employed FEA package may be used. [ABSTRACT FROM AUTHOR]

By the logical statements and linear inequalities, a new modeling method named bi-switching status modeling (BSM) method is presented to model the dc–dc converters in this paper. Compared with other modeling methods, such as the state-space averaging method and the mixed logical dynamical (MLD) method, first, the BSM method can describe continuous conduction mode and discontinuous conduction mode operations of the dc–dc converters as a unified bi-switching status model. Second, the BSM method is more precise than the state-space averaging method because there is no approximate assumption. Third, the constrains of the operating modes in the BSM method can be simplified as a consolidated inequality, which means that the model obtained by the BSM method is more concise than that obtained by the MLD method. Simulation and available experiments of a buck converter verify the effectiveness of the proposed BSM method. [ABSTRACT FROM PUBLISHER]

In this paper, average modeling and analysis of a dual-supercapacitor bank, actively balanced by a bidirectional buck–boost converter, is presented. In such a system, natural balancing is achieved when the converter is operated in open loop with 50% duty cycle, eliminating the need for measuring the voltage of each storage device. Nevertheless, excessive currents arise even for slight voltage misbalance because of the highly underdamped nature of the system. In order to remedy this drawback, bidirectional pulse-by-pulse inductor current limitation is introduced, which is equivalent to adding a peak-current-mode-like control loop to the system. Since the duty cycle never exceeds 50%, compensation ramp is not required to maintain stability. On the other hand, while the uncontrolled system dynamics is linear, introducing the current limit mechanism turns the closed-loop dynamics into a nonlinear one, burdening the analysis task and thus calling for suitable average model to perform fast simulations for system analysis. Therefore, dynamical equations of the system are developed in order to derive the switching-cycle-averaged model and reveal the tradeoff between current limit level, balancing time and efficiency for the worst case of imbalance. Simulations and experiments support the presented findings. [ABSTRACT FROM PUBLISHER]

The doubly fed induction generator (DFIG) is normally controlled with stator-flux orientation. The DFIG is a poorly damped system with a natural frequency near the grid frequency. This leads to natural oscillations on the stator flux and on other variables. When voltage dips occur, there are oscillations on the stator flux that produces electromotive forces and consequently disturbances on the rotor currents. This paper presents a comprehensive study of the DFIG during voltage dips. The method presented in this paper, valid for symmetric and for asymmetric voltage dips, is based on the classical model of the induction machine with stator flux orientation and neglects only a small part of the cross-coupling terms. The response depends on the design methodology of the proportional-integral inner controllers. Analytical, simulation, and experimental results are shown. The analysis and results can be divided into two sets depending if the voltage dip magnitude is smaller or deeper than 0.5 p.u. [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]

Molecular communication (MC) will enable the exchange of information among nanoscale devices. In this novel bio-inspired communication paradigm, molecules are employed to encode, transmit and receive information. In the most general case, these molecules are propagated in the medium by means of free diffusion. An information theoretical analysis of diffusion-based MC is required to better understand the potential of this novel communication mechanism. The study and the modeling of the noise sources is of utmost importance for this analysis. The objective of this paper is to provide a mathematical study of the noise at the reception of the molecular information in a diffusion-based MC system when the ligand-binding reception is employed. The reference diffusion-based MC system for this analysis is the physical end-to-end model introduced in a previous work by the same authors, where the reception process is realized through ligand-binding chemical receptors. The reception noise is modeled in this paper by following two different approaches, namely, through the ligand-receptor kinetics and through the stochastic chemical kinetics. The ligand-receptor kinetics allows to simulate the random perturbations in the chemical processes of the reception, while the stochastic chemical kinetics provides the tools to derive a closed-form solution to the modeling of the reception noise. The ligand-receptor kinetics model is expressed through a block scheme, while the stochastic chemical kinetics results in the characterization of the reception noise using stochastic differential equations. Numerical results are provided to demonstrate that the analytical formulation of the reception noise in terms of stochastic chemical kinetics is compliant with the reception noise behavior resulting from the ligand-receptor kinetics simulations. [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]

Hybrid vector clock(s) (HVC) provide a mechanism to combine the theory and practice of distributed systems. Improving on traditional vector clock(s) (VC), HVC utilizes synchronized physical clocks to reduce the size by focusing only on causality where the physical time associated with two events is within a given uncertainty window $\epsilon$ and letting physical clock alone determine the order of events that are outside the uncertainty window. In this paper, we develop a model for determining the bounds on the size of HVC. Our model uses four parameters, $\epsilon$ : uncertainty window, $\delta$ : message delay, $\alpha$ : communication frequency and $n$ : number of nodes in the system. We derive the size of HVC in terms of a delay differential equation, and show that the size predicted by our model is almost identical to the results obtained by simulation. We also identify closed form solutions that provide tight lower and upper bounds for useful special cases. We show that for many practical applications and deployment environments in Amazon EC2, the size of HVC remains only as a couple entries and substantially less than $n$ . Finally, although the analytical results rely on a specific communication pattern they are useful in evaluating size of HVC in different communication scenarios. [ABSTRACT FROM AUTHOR]

Model-based observers are widely applied in state-of-charge (SOC) estimation. The existing model-based observers can achieve high precision in theory, but the estimation precision is influenced by many factors in practical application. The impact of the possible error sources on the SOC estimation needs to be clarified in order to enhance the practical estimation accuracy. In this paper, the effect of five error sources in the model-based SOC observer is analyzed, including the initial error, the capacity error, the current measurement error, the voltage measurement error, and the model prediction error. Both theoretical derivation and simulation analysis are implemented. The results show that the initial SOC error converges to zero during the iteration, while the errors of the capacity, current, voltage, and model cause the SOC estimation error in different extents. Quantitative comparisons of these different error sources are carried out in order to determine the critical factors of the SOC estimation. The SOC estimation accuracy is mainly limited by the model precision under the current hardware and software conditions of the battery management system, indicating a possible improving direction of the SOC estimation. [ABSTRACT FROM AUTHOR]

This paper proposes a general methodology to analyze the interleaved pulse width modulation (PWM) dc–dc converter. A unified and simple model is constructed and the complete electrical behaviors of the interleaved PWM dc–dc converter could be predicted. Features of the interleaved PWM dc–dc converter are investigated based on this model. Insightful conclusions are derived and can be used to guide designs. This model could serve as a solid foundation for further research, and it is valid to all the common interleaved PWM dc–dc topologies. As an example of its applications, the input current of the interleaved boost converter is investigated in detail. Simulation and experimental results have successfully validated against theoretical analysis. [ABSTRACT FROM AUTHOR]

In this paper, we present a physics-based model for accurate simulation of intermodulation distortion (IMD) in GaAs pseudomorphic HEMTs at 2 GHz. We combine the surface-potential-based drain-current model previously developed by us with the standard topology used in these devices for accurate nonlinear simulations. The proposed model is in excellent agreement with measured IMD data at multiple dc bias points varying from close-to cutoff voltage to the high-conduction region. We also analyze the impact of various model elements and physical effects on IMD behavior of the device. Furthermore, the popular Volterra series coefficients for the drain current nonlinearity are analyzed and their relative importance with respect to the overall device nonlinearity is assessed. [ABSTRACT FROM PUBLISHER]

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]

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]

Photovoltaic (PV) system performance is influenced by several factors, including irradiance, temperature, shading, degradation, mismatch losses, soiling, etc. Shading of a PV array, in particular, either complete or partial, can have a significant impact on its power output and energy yield, depending on array configuration, shading pattern, and the bypass diodes incorporated in the PV modules. In this paper, the effect of partial shading on multicrystalline silicon (mc-Si) PV modules is investigated. A PV module simulation model implemented in P-Spice is first employed to quantify the effect of partial shading on the I–V curve and the maximum power point (MPP) voltage and power. Then, generalized formulae are derived, which permit accurate enough evaluation of MPP voltage and power of mc-Si PV modules, without the need to resort to detailed modeling and simulation. The equations derived are validated via experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, we analyze an IEEE 802.11e enhanced distributed channel access (EDCA) based single-hop ad hoc network under bursty traffic addressing all four differentiation parameters. We investigate the performance of the network considering both nonsaturation and saturation regimes under an error-prone channel. We develop an accurate analytical model for the network and validate it with a simulation model. Our results indicate that adjusting the transmission opportunity (TXOP) limit in accordance with the burst size distribution can considerably improve the performance of the network and the burst delay, which is an important parameter for the application. Although large TXOP allocations improve the medium utilization and extend the stability region of the network, serious unfairness and security concerns due to the possibility of denial of service attacks may arise. The results also show that under bursty traffic, the TXOP limit can play an important role in helping the lower priority classes avoid starvation. [ABSTRACT FROM PUBLISHER]

Although different broadcasting techniques are widely deployed in wireless networks, there are limited comprehensive analytical frameworks to evaluate the performance of such schemes. In this paper, based on a rigorous theoretical analysis, upper bounds on the network coverage and the total number of transmissions (corresponding to network energy consumption) of flooding and its popular variant probabilistic flooding are derived. The analysis is performed for a static multihop ad hoc wireless network when the network is in saturated condition. To consider a realistic medium-access control (MAC) layer algorithm, successful signal reception is based on the protocol model, and nodes employ carrier-sense multiple access. Based on the concept of marked point process, two different approaches, i.e., hop based and time based, are proposed. In the hop-based approach, an upper bound on network coverage and energy consumption is derived for any serving policy and queuing delay that broadcasted packets experience. This approach can be easily extended to multiple-source scenarios. The time-based approach is appropriate for the case of known service policy and queuing delay, and it predicts the time-domain behavior of the broadcasting schemes, as well as other mentioned parameters. We show that the two bounds are very close to each other. The first approach has less complexity, whereas the second approach provides a tighter bound. As an interesting result, we analytically demonstrate that the disjoint analysis of MAC and network layers provides a much simpler solution, whereas the obtained results are also upper bounds on the network coverage. Simulation results validate our analytical model and demonstrate its tightness for real scenarios. [ABSTRACT FROM PUBLISHER]

Networks-on-chip (NoCs) have recently emerged as a scalable alternative to classical bus and point-to-point architectures. To date, performance evaluation of NoC designs is largely based on simulation which, besides being extremely slow, provides little insight on how different design parameters affect the actual network performance. Therefore, it is practically impossible to use simulation for optimization purposes. In this paper, we present a mathematical model for on-chip routers and utilize this new model for NoC performance analysis. The proposed model can be used not only to obtain fast and accurate performance estimates, but also to guide the NoC design process within an optimization loop. The accuracy of our approach and its practical use is illustrated through extensive simulation results. [ABSTRACT FROM AUTHOR]

This paper presents an analytical model for input, output, and reverse capacitance of a normally on AlGaN/GaN high-electron mobility transistor (HEMT) with a gate field-plate structure, when the device is in the subthreshold regime. Together with the existing model for the output I–V characteristics, the proposed capacitance model provides the complete set of analytical equations that relate the physical design parameters to the electrical characteristics of the device. The model was verified by the experimental characterization of a HEMT. In comparison to the physics-based models implemented in Finite Element Analysis tools, the obtained capacitance model has substantially lower level of complexity and, therefore, it is more suitable for implementation into iterative design optimization algorithms. In order to verify the proposed model for such usage, the prototype of a high-frequency buck converter was built, using previously modeled GaN HEMT as the main switch. The hybrid analytical-behavioral power loss model of a high-frequency buck converter was implemented into Simplorer simulation tool, using the proposed physics-based model as the device description for the capacitive part. The efficiency measurements showed good agreement with the simulation results, even at 20 MHz of switching frequency in the low range of the output power. [ABSTRACT FROM AUTHOR]

From the controller design framework, a simple analytical model that captures the dominant behavior in the range of interest is the optimal. When modeling resonant circuits, complex mathematical models are obtained. These high-order models are not the most suitable for controller design. Although some assumptions can be made for simplifying these models, variable frequency operation or load uncertainty can make these premises no longer valid. In this study, a systematic modeling order reduction technique, slowly varying amplitude and phase (SVAP), is considered for obtaining simpler analytical models of resonant inverters. SVAP gives identical results as the classical model-order residualization technique from automatic control theory. A slight modification of SVAP, slowly varying amplitude derivative and phase (SVADP) is applied in this paper to obtain a better validity range. SVADP is validated for a half-bridge series resonant inverter and for a high-order plant, a dual-half bridge series resonant inverter giving analytical second-order transfer functions for both topologies. Simulation and experimental results are provided to show the validity range of the reduced-order models. [ABSTRACT FROM PUBLISHER]

In this paper, the modeling and tracking control problem of unmanned turret system (UTS) is addressed. To guarantee the feasibility of modeling and control, three-axis stabilization is analyzed. A complete mathematical model for UTS is then established based on robotic analysis technique. The coupling model also takes inner parameters perturbation and external disturbances into consideration. To achieve rapid response and high tracking precision, a fast nonsingular terminal sliding mode control scheme is designed compounding with extended state observer (ESO). Owing to the estimating ability of ESO, this control scheme can reduce the chattering phenomena remarkably. Finally, simulation results are presented to illustrate effectiveness of the control strategies. [ABSTRACT FROM PUBLISHER]

This paper presents results on behavior modeling of a general purpose metal–oxide–semiconductor field-effect transistor (MOSFET) for simulation of power electronics systems requiring accuracy both in steady state and in switching conditions. Methods of parameters extraction, including nonlinearity of parasitic capacitances and steady-state characteristics, are based on manufacturer datasheet and externally measurable characteristics. The MOSFET template is written in the MAST language and simulated in the SABER simulator. Experimental validation of the N-channel power MOSFET-type IRFP240 (Fairchild Semiconductor) rated at 20 A/200 V is performed in a dc/dc boost converter. The main features of the developed model have been compared with the properties of an analytical MOSFET model and a general MOSFET model embedded to a SABER simulator. [ABSTRACT FROM PUBLISHER]

The step-stress model is becoming quite popular for analyzing lifetime data obtained from accelerated life testing experiments. In the usual step-stress experiment, stress levels are allowed to change at each step to get rapid failure of the experimental units. The simple step-stress model under different censoring schemes based on Weibull lifetimes is considered in this paper. It is assumed that the lifetime distributions of the experimental units have different scale parameters at different stress levels, but they have the same shape parameter. Moreover, it is assumed that the lifetimes follow the Khamis-Higgins model. It is further assumed that, as the stress level increases, the scale parameter also increases. We provide Bayesian inference of the unknown parameters of the Weibull distribution under this order restriction on the scale parameters. Monte Carlo simulations have been performed to see the effectiveness of the proposed method, and a data set has been analyzed for illustrative purposes. [ABSTRACT FROM PUBLISHER]

DC hybrid power systems are of interest for future low emission, fuel-efficient vessels. In spite of the advantages they offer onboard a ship, they result in a complex, interconnected system, which requires effective analysis tools to enable a full realization of the advantages. Modeling and simulation are essential tools to facilitate design, analysis, and optimization of the system. This paper reviews modeling of hybrid electric ship components including mechanical and electrical elements. Power electronic converters are modeled by nonlinear averaging methods to suit system-level studies. A unified model for bidirectional converters is proposed to avoid transitions between two separate models. A simulation platform using the derived models is developed for the system-level analysis of hybrid electric ships. Simulation results of power sharing among two diesel generators, a fuel cell module, and an energy storage system are presented for three modes of operation. [ABSTRACT FROM AUTHOR]

This paper proposes a dynamic time simulation model for long-term generation capacity investment decisions in the presence of either perfect or imperfect electricity market. The model is based on system dynamics concept in which the dynamics of capacity construction is traced using the forecast of electricity price cleared in the short-term electricity market. Both the perfect and oligopolistic competitions are considered and a market power index is defined to evaluate the competition level of the electricity market. The short-term and long-term dynamic analysis are used to represent the generation firms' behavior in bidding strategy and capacity investment, respectively. Both possibilities of using forward bilateral contracts and application of wind power generation have been assessed individually in the proposed model in order to mitigate the market power. The time simulation results derived from a case study demonstrate the effectiveness of the model in illustrating the oligopoly in electricity marketplace and also the alternative decisions to attenuate it. Such a decision tool enables both the generation firms and the regulators to gain perfect insight into the oligopoly and its consequences in the long-term capacity investment in the electricity market. [ABSTRACT FROM PUBLISHER]

A behavioral average-circuit model that analyzes hybrid converters that include a switched inductor and switched capacitors is presented. The model can be used to calculate or to simulate the average static, dynamic, and small-signal responses of hybrid converters. The model is valid for all operation modes of the switched capacitor converters (SCCs) operating in the continuous and discontinuous conduction modes of the switched inductor converter and is compatible with circuit simulators that include dependent sources. The model was verified with simulations and experimentally. The experimental converter included a boost converter followed by a \times 3 SCC. Good agreement was found between the behavior of the proposed average model, full circuit simulations, and experimental results. [ABSTRACT FROM PUBLISHER]

In this paper, we use dynamic-bubblesort technology [4] to analyze general first-in-first-out K-queue homogenous fork/join queuing (HFJ) systems for any K \ge 2. Jobs arrive with a mean rate \lambda and a general arrival distribution. Upon arrival, a job forks into K tasks. Task k,k= 1,2, \ldots,K, is assigned to the kth queuing system, which is a first-in-first-out server with a general service distribution and an infinite capacity queue. A job leaves the HFJ system as soon as all its tasks complete their service. We mathematically prove an upper bound solution for the mean response time that we denote by T_K. The upper bound solution of general K-queue HFJ systems for any K \ge 2 is very simple and practical—one only needs to simulate a small number of queues (e.g., 16 queues). The tightness is evaluated by comparing with the simulation of thousands of queues for three different HFJ cases. The maximum offset for our upper bounds over all the simulations is less than 5 percent. The corresponding source codes (reusable) are offered on our website for others to use. [ABSTRACT FROM AUTHOR]

Surface-potential-based drain current model is presented for amorphous InGaZnO thin-film transistors considering both exponential deep and tail trap states densities in the energy gap. The trap states densities are determined by the numerical calculation on the basis of the assumption that the trapped carrier concentration is much higher than the free carrier concentration. The analytical drain current model is developed consistent with the numerical calculation, and verified by the experimental data at different temperatures. [ABSTRACT FROM PUBLISHER]

This letter establishes the stationary frame equivalent model of proportional-integral (PI) controller in dq synchronous frame. Although both PI controller in dq synchronous frame and proportional-resonant (PR) controller in stationary frame achieve zero steady-state error when tracing fundamental frequency reference, their amplitude and phase characteristics differ greatly from each other except for fundamental frequency. Using stationary frame PR controller to replace PI controller in dq synchronous frame directly leads to analytical errors, especially in low frequency stage. Another straightforward analysis method is to use stationary frame PI controller to replace PI controller in dq synchronous frame, however the coupling terms in dq synchronous frame are ignored and the approximation is not accurate. The accurate stationary frame equivalent model of PI controller is established. For system controlled in dq synchronous frame, the established model can be used to precisely predict system performance and thus guides control parameters design process. Theoretical analysis is presented and validity of the model is evaluated by simulation. [ABSTRACT FROM AUTHOR]

A novel cosimulation algorithm that combines physical-model-based multiphysics simulation with equivalent-model-based circuit simulation is proposed. In the algorithm, multiphysics simulation couples multiple physical equations (e.g., the electromagnetic, semiconductor transport, thermodynamics equations, etc.) to be solved numerically by an iterative approach. The multiphysics simulation is for modeling the electrothermal behavior of semiconductor devices, and then, it is incorporated into the circuit simulation to extend the simulation from semiconductor devices to circuits. Employing the proposed algorithm, sample numerical results for the temperature effect on circuits comprising commercial p-type–intrinsic–n-type diodes with a model number of mot_bal99lt1 are obtained and compared to measurement data. The comparison shows a good agreement between these two sets of data, which validates the feasibility and accuracy of the proposed algorithm. Moreover, the proposed algorithm can provide a useful physical mechanism for understanding temperature effect on semiconductor devices and circuits. [ABSTRACT FROM PUBLISHER]

Model-set design is one of the most important topics of the multiple-model (MM) approach, which is the state of the art for many estimation, control, and modeling problems. The work presented here proposes a general systematic model-set design method in the parameter space of a system based on number theoretic (NT) methods for design of statistical experiments. The system is characterized by uncertain parameters that describe the mode space, and the models used in the model set are designed to approximate the mode by minimizing distribution mismatch. Two types of $F$-uniform model sets that perform well are proposed: one by the NT methods, the other according to an $F$-centered discrepancy. In order to improve the performance of the $F$-uniform model sets further, two types of expected mode augmentation (EMA) are applied. Simulation examples are given and compared with results from the Monte-Carlo method to demonstrate the designs and their performance. [ABSTRACT FROM PUBLISHER]

An analytical compact drain current model for undoped (or lightly doped) short-channel triple-gate fin-shaped field-effect transistors (finFETs) is presented, taking into account quantum-mechanical and short-channel effects such as threshold-voltage shifts, drain-induced barrier lowering, and subthreshold slope degradation. In the saturation region, the effects of series resistance, surface roughness scattering, channel length modulation, and saturation velocity were also considered. The proposed model has been validated by comparing the transfer and output characteristics with device simulations and with experimental results. The good accuracy and the symmetry of the model make it suitable for implementation in circuit simulation tools. [ABSTRACT FROM PUBLISHER]

Numerical addition theorems of both axially anisotropic and axially isotropic parallel-plate modes are derived using a method based on boundary integral equations. This leads to a generalized multiple scattering (GMS) method for signal/power integrity analysis of dense vias in an arbitrarily shaped plate pair, which overcomes the limitation of the conventional multiple scattering method depending on the analytical addition theorems in an infinitely large or a finite circular plate pair. Both the numerical addition theorems and the GMS method have been validated by comparing results with either analytical expressions for special cases or full-wave simulations for more general cases. Several examples are provided to demonstrate the advantages of the generalized method over previous via models by taking into account the axially anisotropic modes due to the asymmetry caused by dense vias and/or arbitrarily shaped power/ground plate edges on via performance. [ABSTRACT FROM AUTHOR]

We propose a closed-form Gaussian sum smoother and, more importantly, closed-form smoothing solutions for increasingly complex problems arising from practice, including tracking in clutter, joint detection and tracking (in clutter), and multiple target tracking (in clutter) via the probability hypothesis density. The solutions are based on the corresponding forward–backward smoothing recursions that involve forward propagation of the filtering densities, followed by backward propagation of the smoothed densities. The key to the exact solutions is the use of alternative forms of the backward propagations, together with standard Gaussian identities. Simulations are also presented to verify the proposed solutions. [ABSTRACT FROM PUBLISHER]