Balanced Mode Research Articles

Multiband multiple‐input multiple‐output antenna with high isolation for future 5G smartphone applications

A multiband high-isolation multiple-input multiple-output (MIMO) antenna using balanced mode and coupled neutralization line (NL) is presented in this article. The balanced modes of dipole and loop antennas, which leads to good isolation intrinsically are used for the 8 × 8 MIMO in the LTE bands 42 (3400-3600 MHz)/Chinese 5G band (3300-3400 and 3400-3600 MHz). The unbalanced mode of loop antennas, which optimized by decoupling structure are designed for the 4 × 4 MIMO in the LTE band 40 (2300-2400 MHz). Therefore, the eight-antenna array is formed by four dipole elements and four loop elements. The simulated and measured results show that the proposed antenna can cover 2300 to 2400 and 3300 to 3600 MHz, with reflection coefficient better than −6 dB and isolation higher than 15 dB. Good radiation performance and low envelope correlation coefficient can also be obtained. Specific absorption rate of user's hand is also discussed in this article.

Математическое моделирование асинхронных тяговых электродвигателей локомотивов с короткозамкнутым ротором

Objective: To analyze processes in asynchronous engines in case of failure occurrence in rotor winding. Methods: Mathematical model of asynchronous locomotive propulsion engine with cage rotor (AD) was applied. Model calculations applied for the solution of the differential equation system by means of numerical integration were given. Results: The presented AD mathematical model makes it possible to assess the influence of engine’s parameters and load on transient behavior of motor start, as well as to conduct the research in an asynchronous engine in case of balanced and unbalanced operation modes in a three-phase system of coordinates. The latter allow for an adequate description of physics in stator windings in case of failures of rotor bar windings of AD locomotives. Basic equations for the locomotive propulsion engine stator and rotor of different coordinate systems were presented. A structural computational scheme of a three-phase asynchronous engine with a squirrel-cage rotor was developed, making it possible to calculate AD transients. The mathematical model was implemented with MATLAB Simulink software package. Practical importance: The results obtained by means of locomotive asynchronous engine simulation in case of failures of rotor bar windings, as well as AD twisting moment alteration in time demonstrated the possibility of using such a model in order to detect the specific features of failure occurrence in AD.

A High-Resolution Data Assimilation Framework for Snow Water Equivalent Estimation across the Western United States and Validation with the Airborne Snow Observatory

AbstractNumerical simulations of snow water equivalent (SWE) in mountain systems can be biased, and few SWE observations have existed over large domains. New approaches for measuring SWE, like NASA’s ultra-high-resolution Airborne Snow Observatory (ASO), offer an opportunity to improve model estimates by providing a high-quality validation target. In this study, a computationally efficient snow data assimilation (DA) approach over the western United States at 1.75-km spatial resolution for water years (WYs) 2001–17 is presented. A local ensemble transform Kalman filter implemented as a batch smoother is used with the VIC hydrology model to assimilate the remotely sensed daily MODIS fractional snow-covered area (SCA). Validation of the high-resolution SWE estimates is done against ASO SWE data in the Tuolumne basin (California), Uncompahgre basin (Colorado), and Olympic Peninsula (Washington). Results indicate good performance in dry years and during melt, with DA reducing Tuolumne basin-average SWE percent differences from −68%, −92%, and −84% in open loop to 0.6%, 25%, and 3% after DA for WYs 2013–15, respectively, for ASO dates and spatial extent. DA also improved SWE percent difference over the Uncompahgre basin (−84% open loop, −65% DA) and Olympic Peninsula (26% open loop, −0.2% DA). However, in anomalously wet years DA underestimates SWE, likely due to an inadequate snow depletion curve parameterization. Despite potential shortcomings due to VIC model setup (e.g., water balance mode) or parameterization (snow depletion curve), the DA framework implemented in this study shows promise in overcoming some of these limitations and improving estimated SWE, in particular during drier years or at higher elevations, when most in situ observations cannot capture high-elevation snowpack due to lack of stations there.

Distributed Frequency Control With Operational Constraints, Part I: Per-Node Power Balance

This paper addresses the distributed optimal frequency control of multi-area power system with operational constraints, including the regulation capacity of individual control area and the power limits on tie-lines. Both generators and controllable loads are utilized to recover nominal frequencies while minimizing regulation cost. We study two control modes:the per-node balance mode and the network balance mode. In Part I of the paper, we only consider the per-node balance case, where we derive a completely decentralized strategy without the need for communication between control areas. It can adapt to unknown load disturbance. The tie-line powers are restored after load disturbance, while the regulation capacity constraints are satisfied both at equilibrium and during transient. We show that the closed-loop systems with the proposed control strategies carry out primal-dual updates for solving the associated centralized frequency optimization problems. We further prove the closed-loop systems are asymptotically stable and converge to the unique optimal solution of the centralized frequency optimization problems and their duals. Finally, we present simulation results to demonstrate the effectiveness of our design. In Part II of the paper, we address the network power balance case, where transmission congestions are managed continuously.

Study on the Psychotherapy of Martial Arts’ Yin-Yang Balance Mode for Negative Emotional Energy Conversion of Neurogenic Depression

Objective:The Psychotherapy of Martial Arts’ Yin- Yang Balance mode to convert the negative Emotional Energy of neurodepressive patients was studied. Methodes: By using the self-rating depression scale (SDS) and self-rating anxiety scale (SAS) for pre-test and post-test. Results: The results showed that there were significant differences in depression and anxiety in patients with neurodepression before and after the test, and the emotions of depression and anxiety go from being serious back to normal state. The Psychotherapy of Martial Arts’ Yin- Yang Balance mode has significant effect on the negative emotional energy conversion of neurogenic depression.

The WIG-craft Aerodynamic Model Parameters Calculation

Abstract The problem of determining the aerodynamic parameters of the model of vehicle in the area of the ground-effect, intended for the synthesis of the control system, is considered. The determination of aerodynamic forces and moments for various stationary flight modes is successfully solved by experimental and numerical methods. Each control element is one more additional varied parameter. The volume of calculations is reduced if we consider only the movement in the neighborhood of the balancing modes. We calculate the centering and balancing of the vehicle for a given full model of the dynamics of the object, taking into account the limitations on the control parameters. The vector of control actions in a generalized form is limited to the maximum values of forces and moments. The tasks of centering, balancing and implementing hierarchical control are solved by mathematical programming methods. Synthesis of generalized control is carried out by classical or synergistic methods. Our preliminary calculation of aerodynamic parameters using the COMSOL Multiphysics software package and the CFD module allowed us to solve all these tasks and we will use it to further calculate the aerodynamics of stationary and non-stationary flight modes in the neighborhood of balancing values.

Dual-Functional MIMO Antenna Array With High Isolation for 5G/WLAN Applications in Smartphones

A dual-functional antenna array operating in the long term evolution (LTE) band 42 (3.4-3.6 GHz) and 5.8-GHz wireless wide area network (WLAN) band (5.725-5.875 GHz) for multiple-input multiple-output (MIMO) applications in 5G smartphones is proposed. The proposed 8-antenna array is composed of two different antenna elements, namely, the folded L-shaped antenna and couple-fed U-shaped antenna. It can be applied in the 8 × 8 (by using 8 antenna elements) and 4 × 4 (by using 4 antenna elements) MIMO system across the LTE band 42 and 5.8-GHz WLAN band, respectively. The quasi-orthogonal polarization, balanced mode excitation and pattern diversity are properly used to achieve high isolation within the operation bands. A prototype of the proposed antenna array was fabricated and measured. The measured isolations in the LTE band 42 (6-dB impedance matching) and 5.8-GHz WLAN band (10-dB impedance matching) are better than 17.1 dB and 34.6 dB, respectively. The total efficiencies are 45%-62% and 52%-59% in the two operation bands, respectively. Besides, the measured envelope correlation coefficients (ECCs) are less than 0.045 and 0.0001, the calculated peak ergodic channel capacities are 37.9 bps/Hz and 19.3 bps/Hz in the 8 × 8 or 4 × 4 MIMO system across the operation bands. Furthermore, user's hand and head effects are investigated and desirable results are obtained. The above results show that this proposed antenna array is a good candidate for MIMO applications in smartphones.

Full-field optical coherence tomography in a balanced detection mode.

We discuss balanced time-domain full-field optical coherence tomography (FF-OCT) realized in a Mach-Zehnder configuration. The balanced detection scheme and spatial phase shifting allow single-shot acquisition and reconstruction in FF-OCT. Combined with a 2D quadrature signal-based demodulation technique applying the Riesz transform, previously illustrated for a dual-shot temporal phase shifting in FF-OCT, we demonstrate the concept for single-shot spatial phase shifting. The monitoring of dynamic processes by time-domain FF-OCT is enabled by this approach. The advantage of single-shot acquisition consists of having no failure due to phase changes over time. However, it demands an accurate registration of both spatially shifted interferograms.

Worst-Case Crosstalk Measurements of Cables—The Multinetwork Analyzer Method

Alien crosstalk (AXT) between Ethernet cables produces interference and poses a potential threat to system security. AXT is challenging to measure in pre-existing installations because of the need for instrumentation at both the near- and far ends. Although commercially available portable equipment for this purpose exists, baluns must be used to excite the balanced modes on Ethernet cables, which restricts the bandwidth and includes the unwanted response of the baluns. Here, a novel measurement system is proposed that does not use baluns. The proposed system uses unbalanced network analyzers that are placed at both ends of the cable run. The analyzers are synchronized and phase locked, and the resulting unbalanced crosstalk measurements are then mathematically converted to balanced and common modes. A new calibration method for multiple network analyzers is presented and validated. Worst-case alien crosstalk measurements of Category 6 unshielded twisted pairs using the proposed system are then presented.

Internal Gravity Wave Emission in Different Dynamical Regimes

AbstractWe aim to diagnose internal gravity waves emitted from balanced flow and investigate their role in the downscale transfer of energy. We use an idealized numerical model to simulate a range of baroclinically unstable flows to mimic dynamical regimes ranging from ageostrophic to quasigeostrophic flows. Wavelike signals present in the simulated flows, seen for instance in the vertical velocity, can be related to gravity wave activity identified by frequency and frequency–wavenumber spectra. To explicitly assign the energy contributions to the balanced and unbalanced (gravity) modes, we perform linear and nonlinear modal decomposition to decompose the full state variable into its balanced and unbalanced counterparts. The linear decomposition shows a reasonable separation of the slow and fast modes but is no longer valid when applied to a nonlinear system. To account for the nonlinearity in our system, we apply the normal mode initialization technique proposed by Machenhauer in 1977. Further, we assess the strength of the gravity wave activity and dissipation related to the decomposed modes for different dynamical regimes. We find that gravity wave emission becomes increasingly stronger going from quasigeostrophic to ageostrophic regime. The kinetic energy tied to the unbalanced mode scales close to Ro2 (or Ri−1), with Ro and Ri being the Rossby and Richardson numbers, respectively. Furthermore, internal gravity waves dissipate predominantly through small-scale dissipation, which emphasizes their role in the downscale energy transfer.

Spontaneous imbalance in the non-hydrostatic Boussinesq equations

Whereas high-frequency waves are valid solutions to the Boussinesq equations in certain limits, their amplitudes are generally observed to be small in large-scale atmospheric and oceanic data. Traditionally, this has led to the development of balance models, reducing the dynamics to only the slow subset. Their solutions, however, can spontaneously generate imbalance in the context of the full equations. To quantify this, we calculate how much energy is transferred from the balanced to the unbalanced part of a turbulent rotating stratified flow that has been initialised to remove high frequencies. We lay out an approach to derive the time evolution of the balanced modes in which their interactions with unbalanced modes are taken into account. This enables us to calculate the budget of balanced (and unbalanced) energy. Our results show that imbalance generation occurs at scales where the Froude and Rossby numbers are still small and the energy spectrum is steep. We find that the scale at which maximum imbalance is generated depends on the peak of the energy spectrum and is invariant to the strength of rotation over the range examined. The unbalanced energy, after being transferred from the balanced component of the flow at larger scales, is cascaded forward and forms a shallow energy spectrum. The steep balanced subrange of the energy spectrum and the shallow subrange cross and form a kink in the total energy spectrum consistent with observed atmospheric and oceanic data. A frequency analysis at different wavenumbers shows that the separation of time scales breaks down at wavenumbers larger than those of maximum imbalance generation, but smaller than the kink of the energy spectrum. Below these scales, there is a single turbulent distribution of frequencies.

Gallium arsenide 0.5–18 GHz antenna front‐end with integrated limiter and differential to single ended low‐noise amplifier

In this study, the authors present a 36:1 relative bandwidth active front-end low-noise amplifier (LNA) with power limiter that has been developed for airborne ultra-wideband receiver systems. The proposed system is driven by an external antenna with a balanced mode with an input impedance of 150 Ω. The whole microwave monolithic integrated circuit (MMIC) embeds a protection from the presence of high-level signals, an ultra-wideband amplifier circuit, an active balun and an impedance transformer. It has a bandwidth ranging from 0.5 to 18.0 GHz with 14 dB gain, 4.5 dB noise figure (NF), 20 dB common-mode rejection and 30 dBm input overload protection. The circuit has a single bias from the output port greatly simplifying its use within a receiving system and can be directly integrated into the antenna mechanical support. Test measurements are also provided.

A balanced fuzzy Cultural Algorithm with a modified Levy flight search for real parameter optimization

Over the last few decades, a plethora of improved evolutionary algorithms was developed with exquisite performance on numerical and real-world problems. Among such algorithms, the Cultural Algorithm is a hyper-heuristic evolutionary algorithm, which explicitly utilizes the knowledge represented in the belief space as an essential component to guide the evolutionary search. In this paper, a new enhanced Cultural Algorithm incorporates a fuzzy system with a modified Levy flight search that is introduced as a new component. The new algorithm namely, b-fCA+mLF, utilizes a balanced search mode using a customized belief space with a quality function to harmonize how the knowledge sources work in parallel. The communication protocols between the population space and the belief space are established through the modified fuzzy acceptance and influence functions. Using these new functions, the best individuals are selected to create new knowledge in an effective manner. Similarly, the best knowledge is selected to evolve the individuals in the population space and guide the evolutionary search towards the promising regions. A modified Levy flight search is proposed and utilizes the information from the belief space as an input to support the evolution process to generate better solutions. The algorithm is tested on the benchmark suite taken from the IEEE-CEC’15 competition on learning-based real-parameter single objective optimization, and is compared with other algorithms including the best performer algorithms in this competition. The results suggest that the proposed algorithm is statistically better and is able to produce higher quality solutions than the other state-of-the-art algorithms. A case study on the well-known 120-bar dome truss design problem is also presented to test the validity of the proposed algorithm for the solution of complex design problems. The results of this problem show the ability of the proposed algorithm to generate good solutions with fewer function evaluations, compared to reported results in the literature and other well-known algorithms.

Mechanical behavior of ECC-encased CFST columns subjected to eccentric loading

To increase the durability and fire resistance of concrete filled steel tube (CFST) columns, engineered cementitious composite (ECC)-encased CFST columns were proposed in this paper. Seven ECC-encased CFST columns with different parameters were tested, the parameters examined included eccentricity ratio, stirrup reinforcement ratio, longitudinal reinforcement ratio and thickness of inner steel tube. The results of the experimental study indicate that the proposed composite column exhibited both superior ductility and high strength under different eccentricity. Three typical failure modes can be observed depending on different eccentricity ratios, which were compression-controlled failure mode, balanced failure mode and tension-controlled failure mode. The thickness of steel tube had significant effects on both load carrying capacity and ductility of ECC-encased CFST columns. The longitudinal reinforcement could enhance the rigidity and loading carrying capacity of ECC-encased CFST columns, and the stirrup could improve the ductility of the composite column. Finally, the failure processes for typical columns were also investigated based on the strain analysis.

On the limited accuracy of balancing the axial fan impeller by automatic ball balancers

The study explores the process of dynamic balancing of the impeller of an axial fan VО 06-300 (Ukraine) by two automatic ball balancers. The computer simulation of the dynamics of the fan in the absence and presence of automatic balancers has confirmed the qualitative results of a previously conducted field full-scale experiment. Thus, the presence of automatic balancers reduces the following: – the mean square value of the vibration velocity in the segment from the rotor start to the beginning of automatic balancing, – the vibration velocity values at two resonant peaks when the rotor is running down, and – the peaks of the vibration velocities in the section of the start of automatic balancing (74 times in the 3D modelling; 5.4 times in the field experiment). The computer simulation of the dynamics of the axial fan with the «on» and «off» gravity forces has allowed determining the following: – the effect of gravity on the accuracy of balancing the impeller decreases rapidly with increasing the cruising speed of the impeller, – when increasing the forces of viscous resistance to the motion of the balls, the effect of gravity on the accuracy of the rotor balancing increases; – at low speeds of rotation (15 r/s), the impeller can be balanced not better than by accuracy class G 2.5, but at the rated speed of 25 r/s, it is balanced according to accuracy class G 1. Herewith, the residual vibration velocities that are caused only by gravity decrease with increasing the rotor speed. The residual vibration velocities that are caused only by the eccentricities of the raceways increase directly proportionally to the rotor speed. Therefore, fast-turning rotors need a more precise installation of automatic balancers. It is recommended to reduce the eccentricity of the raceway of the automatic balancer at least 2.5 times in relation to the maximum permissible value. Residual vibration velocities in the automatic balancing mode (up to 3 mm/s) on the test fan are mostly caused by gravity. The probable causes of residual vibration velocities are eccentricities of the raceways of the automatic balancers, standstill of the balls (lack of reaction to small unbalances), etc. Therefore, residual vibration velocities can be reduced at the stages of manufacturing and installing automatic balancers into a fan.

Сравнительный анализ результатов экспериментального исследования несимметричных режимов работы трехфазного трансформатора и данных полнофазного моделирования

Achieving better energy efficiency and quality of electrical power supply in distribution networks is a multipronged problem, which should be solved with reference to unbiased criteria. Data obtained from load flow analysis of the network under study serve as the main criterion in estimating the efficiency of technical solutions and administrative measures aimed at decreasing technical and commercial losses and improving the key electric energy quality indicators. At the same time, achieving better accuracy of a numerical analysis of electrical networks with loads unevenly distributed among the phases, including, in particular, distribution networks, still remains a significant problem in the electric power industry. The single-line equivalent circuits, which are conventionally used in engineering applications, do not allow the steady-state operating conditions of a three-phase electric network containing multiple sources of imbalance to be analyzed with sufficient accuracy. Under such conditions, it is reasonable to make a shift for using a three-phase representation of the network under study. This approach involves the need to construct three-phase equivalent circuits of electrical equipment, determine their parameters and use them for analysis. The article describes a conceptual approach for constructing the three-phase model of a three-phase two-winding transformer with a wye - grounded wye winding connection circuit, which is widely used in distribution networks. The following experiments were carried out on the test bench: open-circuit test, short-circuit test, load operation tests, open-circuit test under zero sequence supply voltage, and open-circuit test and load operation tests with one phase disconnected. Part of the experimental data was used to calculate the parameters of the three-phase equivalent circuit and to model a three-phase transformer in the MATLAB environment based on the described method.A comparison between the simulated and the experimental data testifies that the performed simulation of various transformer operating conditions yields highly reliable and accurate results. In the balanced mode, the maximum and minimum errors of simulating the main parameters were found to be 4.78 and 2.13%, respectively. In the unbalanced mode, the maximum and minimum errors of simulating the main parameters were found to be 6.6 and 0.78%, respectively. The obtained results allow a conclusion to be drawn that the proposed model of a three-phase two-winding transformer with the wye - grounded wye winding connection circuit adequately reflects the properties of a real transformer. The proposed technique allows the key properties of a three-phase transformer to be revealed, namely, the redistribution of magnetic fluxes among the magnetic core legs and the presence of voltage across the secondary winding when one of the primary winding phases is open. It can also be inferred that a three-phase transformer has a balancing effect.

EQUAL: Energy and QoS Aware Resource Allocation Approach for Clouds

The popularity of cloud computing is increasing by leaps and bounds. To cope with resource demands of increasing number of cloud users, the cloud market players establish large sized data centers. The huge energy consumption by the data centers and liability of fulfilling Quality of Service (QoS) requirements of the end users have made resource allocation a challenging task. In this paper, energy and QoS aware resource allocation approach which employs Antlion optimization for allocation of resources to virtual machines (VMs) is proposed. It can operate in three modes, namely power aware, performance aware, and balanced mode. The proposed approach enhances energy efficiency of the cloud infrastructure by improving the utilization of resources while fulfilling QoS requirements of the end users. The proposed approach is implemented in CloudSim. The simulation results have shown improvement in QoS and energy efficiency of the cloud.

Regional Transport Matrix Study of PM2.5 in Jingjinji Region, 2015

By coupling particle source apportionment technology (PSAT) with a comprehensive air quality model with extensions (CAMx), the regional transport matrix of PM2.5 was built for 13 cities in the Jingjinji Region in 2015. Results showed that the major contributor to PM2.5 was local source emissions, contributing 21.49%-68.74%, The internal transport from in-region sources contributed 13.31%-54.62% and the external transport from out-region sources contributing 13.32%-45.02% were also significant. The spatio-temporal distribution of the PM2.5 transport matrix was characterized by geographical, meteorological, and source patterns. Local emissions exerted the most significant impact on the central part of Jingjinji in winter, while regional transport contributed more to the southern region in other seasons. By assessing the input/output and activity of PM2.5 transport, Langfang, Hengshui, Chengde, Qinhuangdao, and Xingtai were receptors; Tianjin, Cangzhou, Tangshan, Beijing, Shijiazhuang, and Handan were sources, and Zhangjiakou and Baoding had a balanced transportation mode. The seasonal matrix of PM2.5 showed significant transport between Beijing and Langfang, Baoding, Chengde, Tianjin, Cangzhou, while the city list for Tianjin and Shijiazhuang differed slightly.

A Hybrid Switched-Capacitor Battery Management IC With Embedded Diagnostics for Series-Stacked Li–Ion Arrays

This paper presents a small form factor dc–dc converter that can be used in a ladder architecture to provide state-of-charge equalization for large-scale lithium-ion arrays. A resonant switched-capacitor converter is implemented in a 180-nm bulk CMOS process that uses a merged-interleaving architecture to affect two-phase interleaving with only a single inductor. The approach has the advantage of reducing passive component volume for a given efficiency and voltage ripple constraint. A bidirectional current-mode control scheme is outlined that uses regulated zero-current switching and partial zero-voltage switching. The design also supports electrochemical diagnostic functions through a fully digital spectroscopic perturbation of cell current. Cell voltage and current are digitized through 10-b SAR analog to digital converters (ADCs), filtered and decimated for off-chip impedance extraction. The converter achieves 94.8% conversion efficiency in 1:1 balancing mode with a total board area less than 1 cm2, and supports bidirectional power transfer >3.7 W.

Awakening strategies from a sleeping mode to a balancing mode for a sphere robot

This paper presents the strategy of awakening a sphere robot from a sleep mode to a balancing mode. The sphere robot is designed on the basis of a single-wheel robot covered with two hemispheres to have the sphere shape with casters to maintain the sleep mode at a specific angle. The sleep angle has been empirically found to be 16 degrees for enabling the sphere robot to be upright position. The gyroscopic force is controlled to perform the awakening strategy of the robot system. Firstly, the key design features such as angular momentum, agility, and controllable bandwidth are investigated to identify three phases such as triggering, stumbling, and stabilizing for the awakening strategy. Secondly, the sphere robot is modeled as an inverted stick and the phase portrait of the model is analyzed. Thirdly, a control law with a compensation algorithm is proposed to enhance the stabilizing performance. Finally, the proposed awakening strategy is verified through experimental studies.