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Neutron depolarization experiments have shown that the intragranular magnetic domain structure of polycrystalline ferrites exhibits a marked grain size dependence. Below a grain size of around $3~\mu \text{m}$ , the magnetic domain structure changes from the two-domain to the mono-domain state. Ferrites composed of mono-domain grains exhibit low dissipation at megahertz frequencies. This is attributed to the absence of intragranular domain wall movement, i.e., a microscopic origin for dissipation in ferrites has been identified. The implications of this clear observation and evidence for a transition from the mono- to two-domain state in ferrites for micromagnetic theory when a single particle becomes monodomain, as well as for the initial permeability mechanisms in polycrystalline ferrites, are discussed. [ABSTRACT FROM AUTHOR]

Due to the great demand of throughput and reliability for multimedia applications in Fifth Generation (5G) networks, many broadcasting systems adopt the Millimeter Wave (mmWave) technology to address the lack of the spectrum resources. As one of 5G-PPP projects, Internet of Radio Light (IoRL) project adopts 40GHz mmWave band to support a high-speed and stable Ultra-High-Definition (UHD) television broadcasting service in the indoor environment. Because of the high frequency property, mmWave bands usually suffers from the high path loss and the penetration loss. Thus, in order to overcome these issues, directional antennas are employed to provide additional power gain while increasing transmission distance. However, the mmWave with directional antennas brings additional problems, such as limited transmission angle and more multipath effects. Therefore, in this paper, for better understanding of impact factors on the signal quality and transmission coverage of the directional 40GHz mmWave band in the indoor environment, a measurement campaign is introduced in detail and the channel characteristics are measured and analysed in varying cases. The mainly concerned characteristics are path loss, shadow fading, average Power Delay Profile (PDP), Root-Mean-Square (RMS) delay spread, arrival rate and coherence bandwidth. All Measured characteristic values are summarised in three tables at the end of this paper. Besides of these, as a reference of channel analysis and a metric of signal quality and effective coverage, Error Vector Magnitude (EVM) of received signal in each case is measured and discussed. Moreover, a simulation is performed based on a statistical channel model to validate the measured results. [ABSTRACT FROM AUTHOR]

It is known that the determination of the good-dice-in-bad-neighborhoods (GDBNs) has been regarded as an effective technique to reduce the value of the defect parts per million (DPPM) by identifying and rejecting the suspicious dice even though they are good in testing. Instead of examining eight immediate neighbors in a small-sized $3\times 3$ window or exploiting simple linear regression, a large-sized window can be used to recognize the broad-sighted neighborhoods and accurately infer the suspiciousness level for any given die. In this paper, the artificial neural networks (ANN)-based method can be proposed to solve the GDBN identification. Furthermore, two enhanced techniques can be further presented to improve the inference accuracy of the original ANN-based method by considering the variation of the time-dependent wafer patterns and the wafer-to-wafer relationship between two adjacent wafers. After applying the two enhanced techniques, the business profits can be improved in the new ANN-based method. Various experiments on two datasets clearly reveal the superiority of the proposed ANN-based method over the other existing methods. In addition to the reduction of the DPPM value, the new ANN-based method can achieve the 1.5X–2X better reduction in the cost of the return merchandise authorization (RMA). On the other hand, the experimental results show that the similar result can also be obtained in the other lower-yield products. By using the new ANN-based method, the relationships on bad dice cross wafers can be captured and the highly-accurate inference results can be simultaneously maintained. [ABSTRACT FROM AUTHOR]

This paper focuses on the current distribution and AC loss of BSCCO/REBCO hybrid tapes. Based on their geometry and E-J character of superconductors, a one-dimensional model is established to compute the current distribution and AC loss under an AC operating current in self-magnetic field. The current distributions of hybrid tapes with different number of REBCO tapes and one BSCCO tape are studied. The numerical and experimental results are in good agreement. According to the current distribution characteristics, AC loss of each tape in the hybrid tape is analyzed and calculated. AC losses of 3 kinds of hybrid tapes are measured and discussed. The method proposed in this paper for AC loss simulation is quite effective for hybrid tapes composited by two or more types of superconducting tapes. [ABSTRACT FROM AUTHOR]

This paper provides a survey of various experimental data available on the value of the propagation path loss of radio waves in a cellular wireless environment. It is shown starting with the Okumuraet al.’s paper on propagation measurements and other available published experimental data that they all exhibit that the electric field varies as $\rho ^{-1.5}$ within a cellular radius of a few kilometers, where $\rho $ is the radial distance of the receiving antenna from the transmitting one. This decay in the fields is equivalent to a propagation loss of −9 dB/octave or −30 dB for a decade of the distance. This value is independent of the nature of the ground, whether it be composed of rural, urban, suburban, or water. This is the first time it is stated that the propagation path loss due to the presence of ground generates a path loss of 90 dB when the signals travel a distance of 1 km. This value is rather large when compared to a loss of 30–50 dB produced by buildings, trees, and similar artifacts. Therefore, the experimental data indicate that the effect of trees and buildings have a secondary influence on the decay of the electric field with distance, the dominant one is the propagation loss over an imperfect ground. Contemporary propagation models do not acknowledge this fact. Outside the cellular radius of a few kilometers, the path loss appears to be 12 dB/octave or 40 dB/decade of distance. In a companion paper, it will be demonstrated that the values for the path loss can be explained from an analytical standpoint without taking recourse to statistics which involves a lot of assumptions on the functional variation of the variables of interest. [ABSTRACT FROM AUTHOR]

The energy transition is aimed to take advantage of the operational flexibility of hydropower to extend the integration of intermittent renewable sources. Consequently, the hydrogenerators will have to operate in regimes far away from their designed best-point operation. In order to accurately assess the impact, this paper presents a useful approach to determine the overall operating efficiency of synchronous generators under intermittent operation. An accumulated average efficiency (AAE) model is proposed and compared against an alternative approach; the weighted average efficiency (WAE) model. It is found that the WAE approach produces unrealistic low efficiencies when the generator operates in synchronous condenser mode (SCM) for long periods. In general, the AAE supersedes the WAE for all the different load distributions that were investigated. This was further illustrated by a worked example and by constructing more complex load distributions. A load distribution dominated by SCM yields a difference as high as $33.18 \,\%$ , while an even distribution deviates $1.43 \,\%$ in their respective efficiencies. Finally, a yearly on-site measurement of our studied $103 \,\mathrm{MVA}$ generator’s concentrated load distribution revealed a discrepancy of $0.67 \,\%$ , which is a significant deviation considering what the operating regime would mean in terms of economic implications. [ABSTRACT FROM AUTHOR]

This paper studies the outage capacity of a network consisting of a multitude of heterogeneous mobile users and operating according to the classical opportunistic beamforming framework. The base station is located at the center of the cell, which is modeled as a disk of finite radius. The random user locations are modeled using a homogeneous spatial Poisson point process. The received signals are impaired by both fading and location dependent path loss. For this system, we first derive an expression for the beam outage probability. This expression holds for all path loss models that satisfy some mild conditions. Then, we focus on two specific path loss models (i.e., an unbounded model and a more realistic bounded one) to illustrate the applications of our results. In the large system limit, where the cell radius tends to infinity, the beam outage capacity and its scaling behavior are derived for the selected specific path loss models. This paper also studies opportunistic schemes that achieve fairness among the heterogeneous users. Numerical evaluations are performed to give further insights and to illustrate the applicability of the outage capacity results even to a cell having a small finite radius. [ABSTRACT FROM PUBLISHER]

This paper presents a decomposed co-design optimization framework for an electric vehicle powertrain equipped with a Continuously Variable Transmission (CVT). We jointly design the sizes of the powertrain components and the energy management strategy, considering the design and the dynamics of the transmission. Specifically, we divide the resulting nonlinear optimization problem into separate hierarchical optimization subproblems leveraging the concept of Analytical Target Cascading (ATC). Furthermore, we compare the proposed decomposition-based strategy with a centralized approach, in which we solve the same problem, and show that the method presented in this paper can be a potential alternative to a centralized optimization formulation for solving the large-scale, complex integrated plant and control system design. Finally, we compare the resulting performance of using a CVT on the vehicle total-cost-of-ownership with that equipped with a Fixed-Gear Transmission (FGT), which is what is commonly implemented in current electric vehicles. Our results show that by jointly optimizing the design of the transmission along with the control strategy, the CVT yields a lower energy consumption and total-cost-of-ownership compared to that of the FGT. [ABSTRACT FROM AUTHOR]

Most researchers focus on designing accurate crowd counting models with heavy parameters and computations but ignore the resource burden during the model deployment. A real-world scenario demands an efficient counting model with low-latency and high-performance. Knowledge distillation provides an elegant way to transfer knowledge from a complicated teacher model to a compact student model while maintaining accuracy. However, the student model receives the wrong guidance with the supervision of the teacher model due to the inaccurate information understood by the teacher in some cases. In this paper, we propose a dual-knowledge distillation (DKD) framework, which aims to reduce the side effects of the teacher model and transfer hierarchical knowledge to obtain a more efficient counting model. First, the student model is initialized with global information transferred by the teacher model via adaptive perspectives. Then, the self-knowledge distillation forces the student model to learn the knowledge by itself, based on intermediate feature maps and target map. Specifically, the optimal transport distance is utilized to measure the difference of feature maps between the teacher and the student to perform the distribution alignment of the counting area. Extensive experiments are conducted on four challenging datasets, demonstrating the superiority of DKD. When there are only approximately 6% of the parameters and computations from the original models, the student model achieves a faster and more accurate counting performance as the teacher model even surpasses it. [ABSTRACT FROM AUTHOR]

The iron loss of doubled-sided linear switch reluctance motor (DLSRM) is analyzed and calculated in this paper. Because of the double salient structure of the switched reluctance motor and the nonlinearity of the magnetization curve of the ferromagnetic material, the flux density waveform is nonsinusoidal. So, it is difficult to calculate the iron loss of DLSRM. This paper mainly introduces the calculation method of dynamic magnetic density of the DLSRM, and basing on this, the simulation model of iron loss of DLSRM is built and compared the iron loss in different parts of the total as a percentage of the motor. Finally, an experimental platform based on DLSRM is built to measure the actual iron loss in the motor and verify the correctness of the calculation of iron loss. [ABSTRACT FROM AUTHOR]

This paper considers the problem of lossy source coding with a specific distortion measure: logarithmic loss. The focus of this paper is on the single-shot approach, which exposes crisply the connection between lossless source coding with list decoding and lossy source coding with log-loss. Fixed-length and variable-length bounds are presented. Fixed-length bounds include the single-shot fundamental limit for average as well as excess distortion. Variable-length bounds include the single-shot fundamental limit for average as well as excess length. Two multi-terminal problems are addressed: coding with side information (Wyner–Ziv) and multiple descriptions coding. In both the cases, the application of the Shannon–McMillan theorem to the single-shot bounds yields the rate-distortion function and the rate distortion-region for stationary ergodic sources. [ABSTRACT FROM PUBLISHER]

This paper is Part II of a two paper series on electrical machine iron loss predictions. The Part II paper is focused on application of, and experimental data comparisons for, a new and unique method for predicting machine iron losses using transient finite element methods. A significant difference of the new method is the manner in which the predictive surface function of loss versus frequency and flux density is arrived at given lamination steel experimental loss test data. [ABSTRACT FROM AUTHOR]

This paper presents several V-band (50–75 GHz) WR-15 and W-band (75–110 GHz) WR-10 waveguide components fabricated using both direct metal laser sintering in aluminum, nickel-chromium, maraging steel (MS), and copper alloys and stereolithography in copper-coated plastic. Printing resolution is analyzed with respect to feature creation. The RF performance and surface roughness are measured, and the loss due to surface roughness quantified. The measured loss for WR-10 at 92.5-GHz ranges from 5.5 dB/m for the copper-plated plastic waveguides to 36.9 dB/m for the nickel alloy and for WR-15 at 62.5-GHz ranges from 11.0 dB/m for the aluminum alloy to 14.4 dB/m for the MS alloy. From a loss budget study, it is found that standard models do not accurately predict loss due to surface roughness for rough surfaces where the height variation is much larger than skin depth $\delta$ . It is also found that for internally complex printing, the MS alloy versions maintain the closest structure to designed components and expected RF performance. This paper presents the current state-of-the-art in available additive-manufactured waveguide components at V- and W-bands. [ABSTRACT FROM PUBLISHER]

In this paper, we consider how to incorporate psychophysical measurements of human visual perception into the loss function of a deep neural network being trained for a recognition task, under the assumption that such information can reduce errors. As a case study to assess the viability of this approach, we look at the problem of handwritten document transcription. While good progress has been made towards automatically transcribing modern handwriting, significant challenges remain in transcribing historical documents. Here we describe a general enhancement strategy, underpinned by the new loss formulation, which can be applied to the training regime of any deep learning-based document transcription system. Through experimentation, reliable performance improvement is demonstrated for the standard IAM and RIMES datasets for three different network architectures. Further, we go on to show feasibility for our approach on a new dataset of digitized Latin manuscripts, originally produced by scribes in the Cloister of St. Gall in the the 9th century. [ABSTRACT FROM AUTHOR]

Vehicular visible light communication (V-VLC) aims to provide secure complementary vehicle-to-everything-communications (V2X) to increase road safety and traffic efficiency. V-VLC provides directional transmissions, mainly enabling line-of-sight (LoS) communications. However, reflections due to nearby objects enable non-line-of-sight (NLoS) transmissions, extending the usage scenarios beyond LoS. In this paper, we propose wide-band measurement based NLoS channel characterization, and evaluate the performance of direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) V-VLC scheme for NLoS channel. We propose a distance based NLoS V-VLC channel path loss model considering reflection surface characteristics and NLoS V-VLC channel impulse response (CIR) incorporating the temporal broadening effect due to vehicle reflections through weighted double gamma function. The proposed path loss model yields higher accuracy up to 14 dB when compared to single order reflection model whereas CIR model estimates the full width at half maximum up to 2 ns accuracy. We further demonstrate that the target bit-error-rate of $10^{-3}$ can be achieved up to 7.86 m, 9.79 m, and 17.62 m distances for black, orange and white vehicle reflection induced measured NLoS V-VLC channels for DCO-OFDM transmissions. [ABSTRACT FROM AUTHOR]

Reconfigurable intelligent surfaces (RISs) provide an interface between the electromagnetic world of wireless propagation environments and the digital world of information science. Simple yet sufficiently accurate path loss models for RISs are an important basis for theoretical analysis and optimization of RIS-assisted wireless communication systems. In this paper, we refine our previously proposed free-space path loss model for RISs to make it simpler, more applicable, and easier to use. The impact of the antenna’s directivity of the transmitter, receiver, and the unit cells of the RIS on the path loss is explicitly formulated as an angle-dependent loss factor. The refined model gives more accurate estimates of the path loss of RISs comprised of unit cells with a deep sub-wavelength size. Based on the proposed model, the properties of a single unit cell are evaluated in terms of scattering performance, power consumption, and area, which allows us to unveil fundamental considerations for deploying RISs in high frequency bands. Two fabricated RISs operating in the millimeter-wave (mmWave) band are utilized to carry out a measurement campaign. The measurement results are shown to be in good agreement with the proposed path loss model. In addition, the experimental results suggest an effective form to characterize the power radiation pattern of the unit cell for path loss modeling. [ABSTRACT FROM AUTHOR]

This paper presents the simulation and experimental results of the tests conducted for losses and temperature assessments on a belt-driven starter generator designed for 48-V mini-hybrid powertrains. In particular, a double three-phase 10-kW induction machine has been selected as the suitable candidate for the application. This paper reports and discusses in detail the experimental calibration of the lumped-parameter steady-state thermal model, particularly concerning the heat transfer thermal parameters. The testing activity has been conducted on a water-cooled prototype. Therefore, the validated thermal model has been used to predict the thermal behavior of the prototype at different load conditions in accordance with the design specifications. In the final part of this paper, some considerations regarding the prototype packaging and the embedded power electronics thermal issues are also reported. [ABSTRACT FROM AUTHOR]

In this paper, previous theory and results regarding Low-Voltage (LV) distribution losses are validated through power-flow simulation using real load data with standard metering resolution. The validated results are then used to build a generalized loss prediction model for arbitrary grid topologies and metering resolutions. The paper provides the theoretical background to build and generalize a loss prediction model based on load variances together with an approach to estimate such variances. The prediction model uses as explanatory variables the variances of the loads. Yet, such variances are usually unknown for the higher metering resolutions, so the model also proposes a method to predict the higher resolution variances based on the standard metering ones. Results are presented to illustrate the approach proposed and to estimate the increase in losses expected for typical LV grids. [ABSTRACT FROM AUTHOR]

Light-weight antenna arrays require utilizing the same antenna aperture to provide multiple functions (e.g., communications and radar) in separate frequency bands. In this paper, we present a novel antenna element design for a dual-band array, comprising interleaved printed dipoles spaced to avoid grating lobes in each band. The folded dipoles are designed to be resonant at octave-separated frequency bands (1 and 2 GHz), and inkjet-printed on photographic paper. Each dipole is gap-fed by voltage induced electromagnetically from a microstrip line on the other side of the substrate. This nested element configuration shows excellent corroboration between simulated and measured data, with 10-dB return loss bandwidth of at least 5% for each band and interchannel isolation better than 15 dB. The measured element gain is 5.3 to 7 dBi in the two bands, with cross-polarization less than -25 dBi. A large array containing 39 printed dipoles has been fabricated on paper, with each dipole individually fed to facilitate independent beam control. Measurements on the array reveal broadside gain of 12 to 17 dBi in each band with low cross-polarization. [ABSTRACT FROM PUBLISHER]

This paper presents a novel two-terminal fault location algorithm without using line parameters. The algorithm is formulated using unsynchronized voltage and current phasors of the fundamental frequency at both ends. The novelty of the proposed method lies in the fact that it takes into account different angles of synchronism mismatch in pre-fault and fault conditions while considering distributed parameter line model and its solution is in closed form. Simulation results and performance comparison with existing methodology are presented under different fault conditions. The simulations were performed on EMTP-RV platform. The algorithm has also been tested with practical data of Power Grid Corporation of India Limited (PGCIL). The test result shows the validity and accuracy of the developed fault location algorithm. [ABSTRACT FROM AUTHOR]

A fast finite element (FE) based method for the calculation of eddy current losses in the stator windings of randomly wound electric machines is presented in this paper. The method is particularly suitable for implementation in large-scale design optimization algorithms where a qualitative characterization of such losses at higher speeds is most beneficial for identification of the design solutions that exhibit the lowest overall losses including the ac losses in the stator windings. Unlike the common practice of assuming a constant slot fill factor $s_f$ for all the design variations, the maximum $s_f$ in the developed method is determined based on the individual slot structure/dimensions and strand wire specifications. Furthermore, in lieu of detailed modeling of the conductor strands in the initial FE model, which significantly adds to the complexity of the problem, an alternative rectangular coil modeling subject to a subsequent flux mapping technique for determination of the impinging flux on each individual strand is pursued. Rather than pursuing the precise estimation of ac conductor losses, the research focus of this paper is placed on the development of a computationally efficient technique for the derivation of strand eddy current losses applicable in design optimization, especially where both the electromagnetic and thermal machine behavior are accounted for. A fractional-slot concentrated winding permanent magnet synchronous machine is used for the purpose of this study due to the higher slot leakage flux and slot opening fringing flux of such machines, which are the major contributors to strand eddy current losses in the windings. The analysis is supplemented with an investigation on the influence of the electrical loading on ac winding loss effects for this machine design, a subject that has received less attention in the literature. Experimental ac loss measurements on a 12-slot 10-pole stator assembly will be discussed to verify the existing trends in the simulation results. [ABSTRACT FROM AUTHOR]

This paper describes Ka-band inductor-shared RF switches and their applications to a 35.2-ps 6-bit true-time-delay (TTD) switched-line (SL) phase shifter (PS). The inductor-shared RF switches share an inductor to match the input and output (I/O) ports of different states, which are realized with a switched inductor for SP ${n}\text{T}$ case and with a shared matching network for DP ${n}\text{T}$ case. The switches are applied to controlling most significant 3 bits of the proposed TTD SL PS. The delay lines and reference lines of the PS are implemented with microstrip lines and inverted microstrip lines in the same space, respectively. The dual-side microstrip lines allow it to have not only a small size but also compensation of the loss difference between the signal lines with different lengths. The least significant 3 bits are implemented with the modified structure of the SL PS, which reduces the size further by replacing a reference line by a series switch. The test chip is fabricated in a 65-nm CMOS process. It operates in the range of 20–30 GHz occupying a 0.18 mm2 core size. Its measured insertion loss and IP1dB are 11 dB and 6.5 dBm at 28 GHz, respectively. The measured gain error and rms delay error are less than 2 dB and 0.7 ps at operation frequencies. [ABSTRACT FROM AUTHOR]

This paper proposes an air-core transformer integration method, which mounts the transformer straight into the multilayer printed circuit board (PCB), and maintains a proper distance between the inner transformer and other components on the top layer. The integration method reduces the PCB area significantly, ensuring higher power density. The design of the complete structure is accomplished with finite element analysis (FEA) to ensure that the unconstrained transformer magnetic field does not affect other components. It is applied to three resonant flyback converters operating at 20 MHz with Si mosfets, 30 MHz, and 50 MHz with enhancement-mode gallium nitride (eGaN) high-electron mobility transistors, respectively. The 30-MHz eGaN prototype achieves the full load efficiency of 80.1% (an increase of 1.1% compared with the 20-MHz Si prototype) and power density of 32 W/in3 at 5-V input and 5 V/ 2 W output. The 50-MHz eGaN prototype achieves the power density of 39.4 W/in3, which is 41% higher than the 20-MHz Si prototype. With the similar efficiency, the overall height of the converters in this paper is less than half of the commercial products, very suitable for low thickness and profile applications. [ABSTRACT FROM AUTHOR]

Ferroelectric and negative-capacitance field-effect transistors (FeFETs and NCFETs) have recently garnered great attention as devices for applications in memory and low-power logic, respectively. As these technologies are pursued, it is critical to have a variety of measurement approaches, including methods familiar to the electron-device and microwave communities that can aid in fully understanding the behavior of ferroelectrics in FeFETs and NCFETs. In this paper, we propose and show the viability of using frequency-domain electrical measurement techniques employing the well-known microwave S-parameters, and their large-signal generalization and X-parameters. Our methods provide the means to trace the intrinsic polarization versus electric-field curve of the ferroelectric, i.e., with the parasitics de-embedded, thereby showing the innate ferroelectric response, which cannot be done using conventional techniques. These methods also enable extraction of all the parameters of the Landau–Khalatnikov equation, which is commonly used to model ferroelectric behavior in FeFETs and NCFETs. This paper hence takes a useful step toward methods familiar to the electron-device community that can help to better understand and optimize FeFET and NCFET technologies. [ABSTRACT FROM AUTHOR]

This paper extends Johnson’s classical theory [Johnson, Proc. IRE 43, 684 (1955)] for the threshold of backward-wave oscillation (BWO) in a traveling-wave tube by considering the effects of: 1) small random variations of the circuit phase velocity along the tube axis and 2) end reflections. We find that both the BWO threshold and BWO frequency are minimally affected by random variations of the phase velocity, but we find that the oscillation threshold depends sensitively on the magnitude and phase of the composite reflection coefficients. [ABSTRACT FROM AUTHOR]

Non-oriented (NO) electrical steels are widely used as core materials in rotating electrical machines, whereas for measurements under alternating magnetization (AM), standardized methods exist; measurements under rotational magnetization (RM) prove to represent a significant problem. In this paper, we performed measurements of both circular rotational and alternating losses in rolling and transverse directions for four types of NO materials of different Si contents and thicknesses by means of a hexagonal rotational single-sheet tester at different frequencies and flux density values. The losses were measured by the electrodynamical method and for confirmation also by the thermal (rise-of-temperature) method. The estimated rotational losses by means of established well-known methods are correlated with the measured ones. Literature reports attempt to estimate losses $P^{\mathrm {(RM)}}$ for circular RM on the basis of losses $P^{\mathrm {(AM)}}$ for AM. A loss ratio factor $\Gamma = P^{\mathrm {(RM)}}/P^{\mathrm {(AM)}}$ is defined which is reported to be close to $\Gamma = 2$. In this paper, $\Gamma $ factors were determined for three different grades of material. The results indicate a rather weak dependence of $\Gamma $ on the grade, however, a strong one on the intensity $B$ of induction. In approximation, $\Gamma = 2$ is valid for rather weak induction of the order $B = 0.6$ T. Induction increases in steps of $\Delta B = 0.1$ T yield decreases of loss ratio by about $\Delta \Gamma = 3$ %. This enables a rough estimation of rotational losses. However, the possibility of estimation is restricted to the circular case of constant modulus and angular velocity of the $B$ vector. Other cases are characterized by different values of both eddy current losses and hysteresis losses, RM involving completely different domain reconstructions compared to AM. For increased frequency, the decrease in $\Gamma $ becomes weaker due to more dominant eddy current losses. [ABSTRACT FROM AUTHOR]

Harmonic loads and unbalanced loading in a distribution transformer lead to higher losses, an increase in temperature that leads to premature failure, and a shorter lifetime. To prevent these difficulties, the rated power of a transformer supplying nonlinear loads or unbalanced load is reduced; commonly known as derating. In this paper, an alternative to traditional loss based derating is proposed. It is shown that derating might actually not be required when contrasted with the traditional approach. A perspective is presented on how to make the kVA rating “adaptive” and utilize the same kVA rating with or without harmonics. Actual field data are presented to support this viewpoint. [ABSTRACT FROM AUTHOR]

This paper describes the traceable measurement of no-load losses of high-voltage transmission lines, including actual no-load loss measurements of 220-kV transmission lines in coastal Peru. The measurement methodology and the evaluation of the no-load losses are discussed in this paper. The development of a new measurement methodology to allow for future live line connections is also described. [ABSTRACT FROM AUTHOR]

This paper describes the calibration of the Volcano ray-tracing engine against channel measurements collected in an urban environment with a state-of-the-art 28-GHz directional channel sounder. A discrete set of rays, representing planar wavefronts propagating between the transmitter and receiver, were extracted from the measurements and characterized in path gain, delay, and 3D angle-of-arrival through super-resolution techniques, with average errors of only 1.2 dB, 0.55 ns, and 2.05° respectively. The extracted rays were then tracked over space as the receiver, mounted on a mobile rover equipped with military-grade GPS, traversed 66 m while amassing a total of 488 channel acquisitions. The tracked rays were then mapped to rays predicted from ray-tracing, originating through specular reflection or diffuse scattering from ambient objects. The mapping enabled object-specific calibration, namely calibrating distinct diffuse-scattering models for buildings, vehicles, and foliage. To our knowledge, this is the first effort to calibrate ray-tracing with object-specific diffuse scattering models against rays individually mapped in the path gain, delay, angle, and space domains. Results, in terms of calibrated ray-tracing parameters, fit-error statistics, and lessons learned, are included. Our chief finding was that, while most papers on millimeter-wave ray-tracing do not even consider diffuse scattering, it accounted for 20% of the total received power, whereas diffraction accounted for less than 1%. [ABSTRACT FROM AUTHOR]

This paper investigates the debt clearing problem in a debt network with complicated debt relations among various debtors. Each pair of debt relations is modeled with both forward debt chain and backward debt chain to simplify the whole debt network with a developed algorithm. A debt clearing strategy is derived and its benefits and managerial implications are shown in risk management. This paper further demonstrates the validation of the approach for sovereign debt analysis and risk analytics using real debt data from ten developed countries. [ABSTRACT FROM AUTHOR]

The significance of measurement data transfer over unreliable channel has emerged in the last decade, due to the spread of sensor networks and the idea of Internet of things. This paper investigates the behavior of the fast Fourier transform (FFT)-based power spectral density (PSD) estimation in the case of data loss. There are different methods available to estimate the PSD, but the hegemony of the FFT is beyond dispute, especially in real-time applications. This paper investigates the behavior of the PSD estimator in the case of different data loss models, and then offers some simple solutions on how the data loss can be handled in PSD estimation, when only moderate computing resources are available. The efficiency of the proposed method is demonstrated by the simulation and measurement results. [ABSTRACT FROM AUTHOR]

In this paper, optimization of the control of an electrical machine allowing a minimization of its total losses is described. It is based on the use of an iron loss model [loss surface (LS) model] coupled to the electromagnetic finite-element simulations of the machine. The LS model is a scalar and dynamic hysteresis model developed many years ago at G2Elab and tested for iron loss prediction in several cases of electric machines. It is first characterized and improved in this paper for M330-35A SiFe sheets. Then, it is associated with a finite-element analysis to compute, in a post-processor mode, the local and global magnetic losses in the machine. For electric vehicle application, the whole torque–speed variation should be investigated. To do that, a quick response surface is constructed from a small number of simulations and the iron loss is determined. Then, a suitable optimization algorithm is developed. This approach is then illustrated by a case study and compared with classical optimization in which only the copper losses in conductors are considered. Gains of up to 50% reduction in the total losses of the machine in certain operating areas are observed. [ABSTRACT FROM AUTHOR]

A switched reluctance motor (SRM) is one of the candidates of rare-earth-free motors for hybrid electric vehicles (HEVs). An SRM has been developed with same interior permanent magnet synchronous motor (IPMSM) dimensions having competitive maximum torque, operating area, and maximum efficiency. However, this SRM has a windage loss of 1.3 kW due to the salient poles of the SRM driven at the maximum rotational speed. In addition, considerable acoustic noise is caused by the salient poles. In this paper, a simple design of a cylindrical outer shape rotor is proposed, and a comparison with the conventional SRM rotor is carried out. It is found that the efficiency is improved due to the windage loss reduction. It is also found that the acoustic noise is significantly reduced in the proposed rotor design. [ABSTRACT FROM AUTHOR]

This paper proposes eye diagram estimation methods for linear feedback shift register (LFSR)-based bit streams in pseudorandom binary sequence (PRBS) test and scrambling. The PRBS test uses the LFSR as a random data source; scrambling suppresses the radiated EMI by exclusive-OR (XOR) between the data and the LFSR. Both cases include the LFSR as the last block, thus, the LFSR dominantly determines the eye diagram. This paper introduced the deterministic and statistical eye diagram for the PRBS test and scrambling, respectively. The deterministic eye diagram was verified by comparing to the measurement; the statistical eye diagram was verified by comparing to the transient simulation. We also compared the voltage bathtub curves for the scrambling. The measurement and proposed method were correlated up to the BER of 10−10. [ABSTRACT FROM AUTHOR]

In this paper, we propose an integral data rectification strategy for phasor measurement units (PMUs) in multi-area power systems, comprising local data processing and central data recovery modules. The local data processing is designed for the purpose of detecting and eliminating false PMU measurements, which is performed in a decentralized manner, based on our previously developed dynamic state estimation technique; whereas the data recovery is performed in a centralized manner at the control center, based on a newly proposed adaptive-phasor approach. The recovered PMU measurements are then utilized in a low-frequency oscillation damping enhancement scheme, which is achieved by a modified proportional-integral (PI) power system stabilizer (PSS) mechanism embedded in the automatic voltage regulator structure of a synchronous generator. Control parameters of the PI-PSS are optimized by maximizing the critical damping ratio of the power system. This paper is intended to make a contribution to the need of high-quality data transmission in modern power grids with contemporary measuring technologies. [ABSTRACT FROM AUTHOR]

The practical considerations for a 50 000 r/min switched reluctance machine are studied in this paper. A novel rotor design topology with a flux bridge is proposed to reduce the windage losses at high speed. The electromagnetic characteristics of this design are analyzed in this paper. In addition, the practical problems of fabricating the prototype and testing it at high speed are discussed. Finally, experimental results are presented and compared with finite-element analysis simulation results. [ABSTRACT FROM PUBLISHER]

This paper discusses fundamental physical mechanisms that are responsible for specific errors of standardized methods of magnetic loss measurements on laminated soft magnetic materials. It is shown that the Poyntings theorem offers an exact distinction between localized loss portions on the one hand and total losses on the other hand. Further, a clear distinction is suggested between mechanisms of hysteresis and eddy currents. The correct applicability of experimental measurements proves to be restricted to cases where the Poynting vector is restricted to normal off-plane components. This represents the only case where total losses can be determined on the basis of surface field and cross-sectional averaged induction. As a consequence, physically “correct” loss measurements are to be restricted to sample regions that exhibit mere axial magnetization, in exact ways. This is attainable with a single sheet tester, the homogeneously magnetized region of which is equipped with an induction coil and a large-area tangential field coil, in consistent ways. [ABSTRACT FROM AUTHOR]

Electric motors and the drive systems approximately consume half of the global electricity consumption. In the European Union (EU), electric motors and the drive systems are estimated to account for about 70% of all industrial electricity consumption. Therefore, mandatory applications accrue from the legislation of governments or unions like the EU for customs and market surveillance or eco-design requirements. The mandatory applications and the global market size find out the necessity of efficiency measurement. There are several compliance and precompliance efficiency test methods in the literature. The compliance tests should execute reliable, accurate, and reproducible results. The purpose of this paper is to define a simple field method that will be used for measuring and determining in-service efficiency at industrial conditions. The proposed method in this paper is an inexpensive and easy method that would help to energy managers and engineers to make correct decision in replacing inefficient motors with efficient and new ones. In this paper, a novel induction motor-efficiency model function has been proposed based on the International Electrotechnical Commission 60034-2-1 standard equations, and a new field test procedure has been used in efficiency estimation. The new efficiency model function variables and constants are determined from the regression analysis, which depends on 86 tests of 437 different load points’ efficiency data. Furthermore, the proposed field test procedure, equations, and compliance test methods are tested on a sample motor in laboratory, and the results are compared to each other. [ABSTRACT FROM PUBLISHER]

Reliable voltage measurement is a pre-requisite for correct operation of a relay's voltage-dependent functions. The secondary circuit of a relay's voltage transformer (VT) is usually fuse-protected. The blowing of a VT's three-phase fuses prevents correct voltage measurement, commonly referred to as the loss-of-voltage (LOV) condition. Relays are equipped with different methods to detect the LOV conditions and avoid confusing them with grid faults. However, this paper shows that existing LOV detection methods are prone to misoperation in the presence of inverter-based resources (IBRs). The paper's findings are corroborated by hardware-in-the-loop testing of relays with the state-of-the-art LOV detection methods. This paper also develops a new LOV detection method for transmission system relays that addresses the unveiled problem. The proposed method considers the fault behavior of IBRs and detects LOVs by examining certain conditions in three stages, namely phase-voltage-check, phase-current-check, and current-transients-check. Simulation studies are used to verify the dependable and secure operation of this new method for different LOVs, faults, IBRs, and VT configurations. The obtained results demonstrate that this method performs successfully regardless of the type of generation units. Moreover, it is sufficiently fast to prevent relay misoperation during LOV conditions and does not require extra hardware. [ABSTRACT FROM AUTHOR]

This paper focuses on the errors affecting the estimation of power switching losses in power semiconductor devices based on integration of the voltage by current product. It is shown that the measured waveforms are not simply delayed by the probes, but some overshoots and distortions are due to the probes, which may not easily be corrected. These effects are the source of errors, particularly in fast transients. This paper shows analyses of simulation and measurements, including probe models. [ABSTRACT FROM PUBLISHER]

This paper investigates the iron loss calculation of permanent magnet (PM) machines undertaking unconventional operations, where the high-frequency alternating armature field is only a fraction of the constant PM field. It is found that the iron loss of PM machines undertaking such unconventional operations cannot be calculated reliably as the conventional summation of all the iron loss harmonics predicted by finite-element (FE) methods due to fake iron loss harmonics. Further investigation is conducted on the influence of current frequency and magnitude, FE mesh, and convergence tolerance on the FE predicted iron loss under unconventional operations. It is then proposed in this paper that the iron loss of PM machines undertaking unconventional operations can be calculated as the summation of only the iron loss harmonics, which are insensitive to the convergence tolerance. The analyses are validated by the experimental results. [ABSTRACT FROM AUTHOR]

The stray load losses in electrical machines represent a non-negligible contribution of the total losses and are a key point for an accurate evaluation of the energy efficiency of the considered device. In this paper, a methodology using the 3-D finite-element (FE) modeling approach and a posteriori loss calculation is presented for the estimation of the stray load losses. The case of a cage induction motor is investigated, and results are compared with the experiment. The simulation is performed at different load conditions using a 3-D FE model with external circuit coupling. [ABSTRACT FROM AUTHOR]

An electrical motor’s inverse thermal model formulates the precision with which its power losses can be predicted from noisy local temperature measurements. This paper proposes constrained linear least square optimization followed by noise smoothing as a method to accurately predict a 37 kW induction motor’s power loss components. The anisotropic heat transfer and complex geometry of the motor are represented well by the motor’s lumped thermal network and 3-D finite element models, which characterize its intrinsic heat-transfer processes. With the inverse solution method, satisfactory temperature to power inverse mapping was achieved for different sets of noisy temperature inputs simulated from analytical and numerical forward solutions. This paper demonstrates that even with measurement noise in input data, if reliable information about the expected response of the system is available, an accurate reconstruction of power losses can be achieved. [ABSTRACT FROM AUTHOR]

A novel scheme for substrate integrated waveguide (SIW) transitions to planar transmission lines is proposed. The idea is the insertion of impedance matching network along with the mode transition realized by a combination of lumped elements. We published earlier similar work. It was a set of the transitions between SIW and microstrip (MS) using lumped elements, and its application as an SIW quadrature power splitter. Throughout that work, the proposed SIW transition using lumped elements was realized focusing only on the MS structure. Now is to widen the use of the proposed transition scheme using lumped elements. In this paper, we propose that transition scheme also works with SIW-to-coplanar waveguide (CPW) and SIW-to-grounded CPW. Also, in addition to the above quadrature power splitter, we show that the proposed scheme can also be used as an SIW balun. Most of the proposed transition schemes yield approximately 0.8- ± 0.5-dB passband insertion losses per target band. Others, such as SIW quadrature power splitter, work with 4- ± 0.5-dB insertion loss per band of 4.2–5.5 GHz, 90° ± 5° phase variation per 4.49–5.9 GHz, and SIW balun works with 4- ± 0.5-dB insertion loss in 4.34–5.29 GHz, 180° ± 5° phase variation in 4.6–5.34 GHz. [ABSTRACT FROM PUBLISHER]

This paper deals with iron losses caused by fringing fluxes generated by the concentrated stator windings of an axial-flux permanent-magnet synchronous machine. Fringing fluxes enter the laminated stator stack perpendicularly to the plane of the laminated silicon steel sheets. They cause additional eddy currents and losses in the sheets. Three approaches for reducing these losses are compared experimentally with a dedicated setup. The setup has no moving parts and makes accurate iron loss measurement possible. The first method directly restricts the eddy-current losses by segmenting the lamination surface. The second method deflects the fringing flux by using soft magnetic composite. The third method magnetically short circuits the fringing flux using ferromagnetic wires. The first method gives the best results, with a reduction of 6% of the total iron loss at an induction level of 0.6 T and a frequency of 200 Hz. [ABSTRACT FROM PUBLISHER]

This paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two sitting) and two dynamic (walk in a fixed place and real walk). The measurement equipment and measurement procedures are described. The mean path loss component is modeled as a log function of distance, the path loss exponent being in the range between 0.4 and 1.6, while a statistical perspective is taken for the other two components, i.e., body shadowing is found to be well modeled by a ognormal distribution and multipath fading by Rice or Nakagami- m distributions, depending on body motion characteristics. The correlation between the selected distributions and empirical data is not lower than 0.95, typically being greater than 0.98. The novelty of this model is that it takes the statistical influence of various parameters and features present in BANs into account, such as body influence, placement of the wearable antennas, user orientation in the environment, dynamism of the BAN scenario, and propagation conditions. [ABSTRACT FROM AUTHOR]

Power system state estimation (SE) plays a crucial role in the success of advanced tools employed for power system analysis and control in Energy Management Systems. SE is responsible for providing a consistent real-time dataset, free from errors that may compromise decision-making and put the system at risk. The presence of criticalities involving elements such as network branches, measuring units or measurements may impose difficulties for the detection/identification of gross errors in the acquired data. The simultaneous unavailability of the elements that form a given criticality makes the grid unobservable. This paper presents a flexible and effective network-based methodology for the integrated identification of critical groups of branches, measurements and measuring units in SE. The proposed algorithms are constructed, having the properties of such criticalities as their central pillar. Tests performed with IEEE 14-, 30-, and 118-bus benchmark systems are presented, and the obtained results show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper introduces experimental and numerical analysis of nozzle ablation in SF6 gas circuit breakers. Ablation and changes in the diameter of a nozzle were measured in the experiments. In addition, an ablation model was developed and simulations of nozzle ablation were carried out. The relationship between geometric changes to the nozzle due to ablation and the injection energy was investigated using both experimental measurements and data predicted by simulation. The predicted values for mass loss and geometric changes to the nozzles tested show similar tendencies to the experimental results. Also, the developed ablation model was applied to the mixture of fluoronitrile and CO2 gas. By predicting flow and pressure changes due to the ablation effect, the interruption performance of gas circuit breakers after repeated testing can be analyzed. [ABSTRACT FROM AUTHOR]

This paper shows that there is very little effect of the silicon content on the hysteresis component of the magnetic losses when two steels with 2.45% and 3.3% silicon were compared. Two non-oriented steels with 2.45 wt% and 3.3 wt% Si have been investigated. The Hysteresis component was measured by two techniques, in an Epstein frame: by a quasi-static test at 5 MHz and by extrapolating the total loss from frequencies above 50 Hz. The results showed that the quasi-static hysteresis loss (5 MHz) is not affected by increased Si content. The method of measurement by extrapolating—from frequencies above 50 Hz—($W_{h}^\ast $) proved inaccurate, as it is influenced by the electrical resistivity of the steels. [ABSTRACT FROM AUTHOR]

In this paper, converters of TE $^{\Box }_{{10}}$ –TE $^{\circ }_{{21}}$ mode and TE $^{\Box }_{{10}}$ –TE $^{\circ }_{{01}}$ mode with similar exciting topologic structures are designed and verified for a cold test of gyro-TWT. Both the proposed converters are composed of three sections, including TE $^{\Box }_{{10}}$ to TE $^{\Box }_{{20}}$ mode converter with ridged twist waveguide, TE $^{\Box }_{{20}}$ to TE+22 mode converter with variable cross-shaped waveguide, and the last section TE+22 to TE $^{\circ }_{{21}}$ or TE $^{\circ }_{{01}}$ mode converter ($^{\Box }$ represents the rectangular waveguide, + represents the cross-shaped waveguide, and ° represents the circular waveguide). The mode converters can be designed step-by-step and exhibit excellent wideband performance and high conversion efficiency. Simulation results reveal that the proposed TE $^{\circ }_{{21}}$ mode and TE $^{\circ }_{{01}}$ mode converters have less than 0.04 and 0.03 dB loss over 13.5- and 12-GHz bandwidths, respectively, while the return loss is below −25 dB. Prototype TE $^{\circ }_{{21}}$ and TE $^{\circ }_{{01}}$ mode converters were fabricated and back-to-back millimeter-wave measurements were performed to verify the design. [ABSTRACT FROM AUTHOR]