Feed screws are used in various industrial machines and robots to convert rotational motions into linear motions. Mechanical screws, such as ball screws and slide screws, transmit force via frictional contacts through which noise and heat are being generated; thus, the drive efficiency is decreased. To address these problems, we have proposed some types of magnetic lead screws (MLSs) without spiral

In recent years, it has been discovered that the magnitude of the connection node voltage is affected by the output power from a photovoltaic (PV) generator and the line impedance when the PV generator, in an increasing trend, is introduced into the distribution system. In this paper, power flow is qualitatively discussed using basic circuit theory comprising the voltage and current vector diagram

In the present work, multiple non existing model order reduction (MOR) techniques for unstable second‐order form systems (SOSs) are proposed. For unstable SOSs, continuous‐time algebraic Lyapunov equations get unsolvable that halt the reduction process. To avoid this problem, unstable SOS is first decomposed into stable and unstable portions and balanced truncation is applied to the stable part. The

In order to develop a detection system of abnormal situations (such as accidents) for a person living alone, SOM (self‐organizing map) of only daily activity sound recorded with a broadband microphone, and detection of abnormal situation are investigated. The SOM was divided into three regions containing 98.9, 1.0, and 0.1% of the number of learned vectors, and transition of the vectors of simulated

High‐throughput screening is important in various fields, and electrochemical approaches are effective because of advantages such as fast response time and electrode array. Hence, we developed a two‐dimensional electrochemical array sensor. However, its signal intensities for lower concentrations of the redox pair (100 μM–100 pM [Fe[CN]6]3−/4−) were unstable; Therefore, in this study, we investigated

Using a lightning mapping array (LMA), we have observed 24 positive cloud‐to‐ground (CG) flashes occurred in three thunderstorm days. These flashes can be apparently grouped into 5 clusters according to their occurrence times. We have obtained the charge structures for both the individual flashes and clusters. It was found that 4 out of 5 clusters of positive CG flashes exhibited either inverter dipolar

This study proposes an extension of the subband adaptive filtering technique to distributed active noise control systems and the details of the algorithm are presented. The computational requirements and convergence performance are examined for a network with a ring topology without constraints in communication. The proposed algorithm divides the signal of each node into several subbands to reduce

The electron temperature and the density of argon arc plasma plume injected into water were observed through optical emission spectroscopic measurement. Argon arc plasma jets were generated with a DC arc current of 40–200 A by a non‐transferred arc discharge plasma torch under atmospheric pressure, and ejected through a nozzle on the anode into water or gas‐phase argon. The electron temperature of

The integrated power system (IPS) with pulse load involves the dynamic processes of millisecond‐level switching period and second‐level pulse period. The characteristics of this kind of multicycle dynamic process cause much difficulty in analyzing system stability. For this reason, this paper presents a multicycle coupling mathematical model of the IPS with pulse load and proposes an algorithm based

Wireless power transmission systems are suitable for use in charging systems for plug‐in hybrid vehicles and electric vehicles, particularly when considering safety and convenience. Wireless power transmission coils are made of litz copper wire to reduce copper losses at high frequencies. However, litz wires are expensive owing to their complicated structure and large number of manufacturing steps

To study the effectiveness of infrared and UV imaging technology to detect zero‐value insulators, the infrared thermal images and UV videos of zero‐value insulators at different positions on insulator strings were collected at different humidities and levels of pollution. The heat and discharge characteristics of the insulator strings were analyzed. The thermal‐electric multi‐physics simulation models

Fifth‐generation mobile communications systems now being developed use antennas with large numbers of antenna elements and are decided to be massive‐MIMO technologies for flexibly changing the antenna beam (beam forming). Obtaining the required directivity for a multielement antenna requires control of the phase and amplitude of the variable phase shifter and variable amplifier built into each antenna

High step‐down DC–DC converters and rectifiers are required for low‐voltage, high‐current applications. This paper proposes a high step‐down all‐passive rectifier to achieve this conversion. In particular, the proposed rectifier is derived via the duality principle from the N‐stage Cockcroft–Walton circuit; the use of the duality principle in designing proposed rectifier is the novelty. In addition

This paper presents an H14 three‐level inverter topology and the corresponding control method for common‐mode voltage (CMV) suppression based on the three phase three‐level neutral‐point‐clamped inverter. Operation performance of the proposed H14 three‐level inverter is first analyzed under different switching patterns, and the corresponding CMV under each operation states is investigated. The control

In this study, we clarify the effectiveness of the energy‐effective techniques for the occupancy lighting control that is based on an occupancy sensor. The time delay from detecting no occupant to turning off the light is used for performing the occupancy control to avoid erroneously turning off the light (hereafter referred to as false‐off). Our experiment was conducted at an actual home environment

T‐type pulse width modulation controlled three‐level circuit is the mainstream topology in current medium power distributed PV inverters, charging station and active power filter system with the advantages of high equivalent switching frequency, high efficiency, small filter inductance and small grid current harmonic. Aiming at the inherent problems of midpoint voltage fluctuation and complex of the

Large‐volume pulsed discharge plasmas have been studied to gain insight on their phenomena and to realize their applications in various areas, such as sterilization, water treatment, and cancer treatment. Since 2000, when a review paper titled ‘Streamer Discharges in Liquids and their Application’ was published, a number of related papers have been reported in the literature; these reports are summarized

We added nanofillers of MgO, Mg(OH)2, SiO2, and TiO2 to epoxy resin by high‐pressure shearing at a content of 1 vol%. The glass transition temperature (Tg), dielectric properties, and mechanical properties were measured for these nanocomposites. As a result, Tg decreases in all the nanocomposites. When the filler is MgO or Mg(OH)2, the increase of the real part (ϵr′) and that of the imaginary part

With the large‐scale integration of wind power and photovoltaic power, as well as the rapid development of power systems in recent years, it is of great significance to study meticulous day‐ahead scheduling methods further. A robust security‐constrained unit commitment (SCUC) approach with the considerations of uncertainty outputs and the corresponding probability correlations is proposed in this paper

To study the influence of environmental factors such as temperature, humidity, wind speed, and air pressure on the detection of corona discharge using ultraviolet imaging, the rod‐plate gap model was used, and the ultraviolet video signals of AC discharge under different environmental conditions were recorded by CoroCAM504 ultraviolet imager, and the environmental factors affecting UV discharge from

This paper presents a novel distributed method for dynamic economic dispatch (DED) problems with cubic fuel cost functions based on the dual alternating direction method of multipliers (D‐ADMM) and interior point method (IPM). This scheme enables us to combine the excellent parallelism of ADMM with the superior convergence properties of the IPM. The idea adopted by the proposed algorithm is that the

With the increase of energy demand, the scale of power grid is expanding, and the difficulty of power grid fault diagnosis is increasing. Aiming at the problem of large power grid fault diagnosis, a method of partition fault diagnosis based on improved Probabilistic neural network (PNN) and gray relational analysis (GRA) integral is proposed. Firstly, the large power grid divided into small areas for

In this study, we propose a new optimization method to determine the control parameters of a step voltage regulator (SVR) to maximize its voltage control characteristic in distribution networks (DNs) with photovoltaic systems. Considering the service life of an SVR, the proposed method evaluates the expected number of tap operations and the voltage control performance based on the past voltage measurements

Although 5G era has come, the comprehensive coverage of 5G will take a long time for the vast number of underdeveloped countries and regions. Therefore, it is still significant to improve the depth coverage of 4G network. Massive Multi‐in Multi‐out (MIMO) is an application of 5G key technology in 4G network. In this study, based on the theoretical principle of beamforming, a special beamforming was

Multifocus image fusion is a technique that can integrate the focus information of different source images into a single composite image. At present, most fusion methods still suffer from problems such as block artifacts, artificial edges, halo effects, ringing effects, and contrast reduction. To address these problems, a novel multifocus image fusion method based on a convolutional deep belief network

Facial micro‐expression recognition is a natural mechanism of facial behavior with subtle muscle movements and short duration, which is widely considered to be hard to recognize. In this paper, we propose the temporal sampling deformation (TSD) to normalize the temporal lengths and conserve time domain information for micro‐expression sequences. A three‐stream combining 2D and 3D convolutional neural

Most face detection and recognition tasks are based on the training of intact facial images and corresponding labels. Both the three‐dimensional (3D) structure and two‐dimensional (2D) appearance from the frontal view of human faces are bilaterally symmetrical in general. However, sometimes, illumination on the left and right halves of faces is uneven. In such cases, the symmetrical characteristic

In this study, population‐based meta‐heuristic algorithms—artificial bee colony, differential evolution, particle swarm optimization, and real‐coded genetic algorithm—are applied to affine template matching for performance comparison. It is necessary to optimize six parameters for affine template matching. This is a combinatorial optimization problem, and the number of candidate solutions is very large

The packaging technology for the medium‐voltage silicon carbide (SiC)‐metal oxide semiconductor field‐effect transistor (MOSFETs) has come a long way since its inception. Now, it is feasible to design half‐bridge power modules based on 10‐kV SiC‐MOSFETs for higher current applications. This paves the way for many application areas for these devices, particularly for medium‐voltage and high‐power applications

A novel tubular single‐phase linear generator with an axially magnetized permanent magnets (PM) mover is proposed in this paper for the application of free‐piston engine, which is an alternative power generation system of next‐generation electric vehicle. The transient 3D with motion electromagnetic field finite element model is created to analyze the EMF and thrust force characteristics of the linear

To enhance the torque of short‐time duty permanent magnet (PM) dual‐redundancy brushless DC motors (DR‐BLDCM) and avoid the motor overheating under a fixed outer diameter and length, a design method based on the optimization of split ratio and stator magnetic density (Bm) considering thermal limitations is presented. The global thermal limitation of DR‐BLDCM is set by limiting loss density. The local

This letter presents several combinations of a convolutional neural network (CNN) and its learning method for rotation‐invariant digit recognition. Rotation data augmentation is widely used for improving rotation invariance. Data augmentation commonly assigns the same label to all augmented images of the same source. However, this learning method causes some collisions between original and rotated

Due to the threshold voltage of diode switches, existing symmetrical voltage equalizers suffer from voltage drops across battery cells. To overcome this problem, this letter presents a novel voltage equalizer for series‐connected batteries. The proposed inductor‐less cross‐coupled topology allows the voltage of each battery cell to be balanced evenly without a threshold voltage drop, because no diode

In recent years, deep learning has achieved very good results because large amounts of learning data have become easily available due to improvements in computer capabilities and big data. However, it has a problem that the accuracy becomes very bad for strong noise. Therefore, in this study, we compare the classification accuracy of existing mainstream neural networks, including broad learning, convolutional

This letter introduces a step‐up multiple‐input single‐output (MISO) ac/dc converter for vibration energy harvesting. Unlike existing ac/dc converters for vibration energy harvesting, the proposed converter generates a stepped‐up output by utilizing some vibration inputs. Furthermore, the proposed converter offers an inductor‐less design without full‐bridge circuits. The effectiveness of the proposed

Correction to the article TEE23147 published in the July issue of IEEJ Transactions on Electrical and Electronic Engineering, Vol. 15, No. 7, 2020, pp. 1032–1039. DOI:10.1002/tee.23147 Table II of the above article was incorrect. It should have read as follows: Table II. Reduction rates (%) in the voltage violating time Case No. 71.7% PV installation 100% PV installation Method 1 Method 2 Method 1

Mathematical modeling of a system plays a vital role in controller design, tuning to meet the desired specifications and process parameter optimization. In this paper, different identification algorithms are implemented in the four‐tank system to demonstrate the superiority of the recommended subspace system identification method (Numeric Algorithms for Subspace State Space System Identification [N4SID])

A battery energy storage system (BESS) is a promising technology to augment the benefits provided by photovoltaic (PV) power generation. This study proposes a method to evaluate the optimal capacity of a BESS for commercial electricity consumers with PV systems. This method considers the aging effect of a BESS and the PV output uncertainty through linear programming and a real‐time control method.

Accurate and reliable fault location technology is essential to the stable operation of the modular multilevel converter‐high voltage direct current (MMC‐HVDC) system. Aiming at the difficulty of locating high‐resistance ground faults on MMC‐HVDC transmission lines, this paper proposes a method for fault location of transmission lines based on wavelet transform and deep belief network (DBN). First

Semantic segmentation has become one of the trending topics in the world of computer vision and deep learning. Recently, due to an increasing demand to solve a semantic segmentation task simultaneously with attribute recognition of objects, a new task named attribute‐aware semantic segmentation has been introduced. Since the task requires to handle pixel‐wise object class estimation with its attributes

Small model interrupters are convenient to investigate interrupting performance of high‐voltage gas circuit breakers in terms of efficiency. However, the equivalence of interruption phenomena of small model interrupters (e.g., interrupting performance, interruption criteria, and geometric sensitivity) to product‐scale interrupters has not been clarified. Interrupting tests with small and large model

To obtain the larger output torque and the higher stability speed accuracy, a novel dual‐magnet brushless DC motor is proposed, and its structure is introduced. The mathematical model is established by the equivalent surface current method, and the magnetic circuit is analyzed by finite element method. The radial and tangential air gap magnetic flux densities of the dual‐magnet scheme are larger and

In the actual operation, converter transformer valve side bushings are subjected to high voltages and large current loads with large number of harmonics simultaneously. In our previous papers, using the 3‐D electromagnetic‐fluid‐thermal coupling analysis method, the 3‐D temperature distribution of a converter transformer valve side bushing was researched, and the heating and dissipation characteristics

Hyperglycemia in critically ill patients leads to severe complications and even death. It was shown that keeping blood glucose (BG) within the range of 80–110 mg/dl (4.4–6.1 mmol/l) reduces mortality and morbidity in intensive care units (ICUs), and many researches for achieving such BG control have been performed. However, maintaining BG within such range is not easy mainly due to the time variability

Chip solder degradation is one of the main factors affecting the reliable operation of insulated gate bipolar transistor (IGBT) modules. However, there are still many challenges to get the real lifetime of chip solder. This paper proposes a lifetime consumption prediction method based on chip solder failure. First, the constant high junction temperature fluctuations are applied to IGBT modules for

For a gas‐solid insulation system with direct current (DC) voltage, the surface charge accumulation and decay phenomenon are directly related to the capacitive‐resistive electric field transition process. The accumulated charges will affect the electrical insulation performance of a gas‐solid insulation system, which is a challenge for the development of DC gas‐insulated metal‐enclosed transmission

The perturbation and observation method (P&O method) is commonly used for maximum power point tracking in wind energy conversion systems. However, the selection of a suitable step size for this method is the key challenge when employing this technique. To address this, the paper presents a new method, called the FLC‐P&O method, in which a combination of fuzzy logic control (FLC) and the conventional

Dissolved gas analysis is an important way to diagnose transformer faults. Compared with the method of establishing a single classifier based on artificial intelligence for diagnosis, ensemble learning (EL) can combine multiple classifiers to achieve stronger generalization ability and better diagnostic performance. But the traditional EL belongs to homogenous ensemble in which the base learners are

A high‐voltage direct‐current circuit breaker is a key equipment to construct a flexible direct current transmission system. Most of the existing design schemes have some shortcomings such as slow fault‐breaking speed, poor current‐limiting effect, large capacity of the arrester, and long reclosing operation time. To solve the above problems, this paper proposes an H‐type high‐voltage direct current

Partial Discharge (PD) detection is an effective tool to diagnose the insulation condition of high voltage (HV) equipment. Among detection methods of PD, the ultra‐high frequency (UHF) method is distinguished by high sensitivity and safety operation. However, the UHF band includes many communication and broadcasting line spectral frequencies, which can be interference against the UHF method. From the

In recent years, with the large‐scale access of distributed generation (DG), the line voltage of the distribution network will be offset, which will adversely affect users. This paper aims at the voltage adjustment of the distribution network. Firstly, the reactive power control methods of distributed static synchronous compensator (DSTATCOM) and electric spring (ES) are studied separately, and then

The conventional artificial neural network (ANN) model is an effective way to detect harmonic signals. However, the solution of the model cannot converge when the initial value of the excitation function (IVEF) is not suitable, causing a large error in harmonic detection, especially in the case of power system noise. We improve the back propagation (BP) neural network (BNN) model by using an adjustable

Time series forecasting is an important type of quantitative model used to predict future values given a series of past observations for which the generation process is unknown. Two of the most well‐known methods for the modeling of linear time series are the autoregressive integrated moving average (ARIMA) and the autoregressive fractionally integrated moving average (ARFIMA). For different datasets

In both the research and engineering fields, missing data is a serious problem that cannot be overlooked. Therefore, available datasets with missing data are a challenge to be modeled by conventional global prediction models. In this paper, we propose a hybrid model consisting of an autoencoder and a gated linear network for solving the regression problem under missing value scenario. A sophisticated

In recent years, several studies have been performed on methods of investigating the periphery of power lines using remote sensing. Among the survey methods using unmanned aerial vehicles (UAVs), those methods are being studied wherein the environment around power lines is photographed by a UAV, and separation measurements are performed by reconstructing the three‐dimensional (3D) point cloud between

This paper presents a deep learning‐based face recognition device. It aims to instantly remind users of the identities of those who they met before in parties or conferences. When greeted, one, who is correctly identified, may frequently feel more respected than another who is mistaken for someone else in the first place. The golden rule suggests one to treat others with respect, and then others will

We have developed a piezoelectric acoustic sensor that responds to rodents' audible frequency range as a front‐end device for a small hearing prosthesis system appropriate for animal experiments. The proposed piezoelectric transducer uses a biomimetic hearing mechanism that mimics bandpass‐filtering functions realized biologically in the cochlear membranes and hair cells of rodents via a frequency‐selective

For pulse train (PT) controlled switching converter operating in continuous conduction mode (CCM), a problem of low frequency oscillation is existed, which enlarges the output voltage ripple. In order to solve this issue, a constant on/off time pulse train (COOT‐PT) control technique with a buck converter is proposed, and the working principle is introduced in detail. Based on the variation of the

When optimizing the design of electrical machines, it is recommended to take into account the effect of the manufacturing processes on the core losses and magnetic properties of the electrical steel. This paper demonstrates a methodology for incorporating the effects of interlocking, a process frequently applied to fix a stack of laminations, on the magnetic properties of the machine core. The methodology

Theoretically, normally‐off silicon carbide (SiC) junction field‐effect transistors (JFETs) do not require a negative gate voltage supply because they are in an off‐state when the gate–source voltage is 0 V. However, most gate drivers for normally‐off SiC JFETs require not only a positive power supply for turning on the JFET but also a negative power supply for turning it off and maintaining a negative