Input Phase Research Articles

Summation of Temporal L-Cone- and M-Cone-Contrast in the Magno- and Parvocellular Retino-Geniculate Systems in Glaucoma.

PurposeThe purpose of this study was to characterize summation of temporal L- and M-cone contrasts in the parvo- (P-) and magnocellular (M-) pathways in glaucoma and the relationship between the respective temporal contrast sensitivities (tCS) and clinical parameters.MethodsPerifoveal tCS to isolated or combined L- and M-cone contrasts (with different contrast ratios, and therefore different luminance and chromatic components) were measured at different temporal frequencies (at 1 or 2 Hz and at 20 Hz) using triple silent substitution in 73 subjects (13 healthy, 25 with glaucoma, and 35 with perimetric glaucoma). A vector summation model was used to analyze whether perception was driven by the P-pathway, the M-pathway, or both. Using this model, L- and M-cone input strengths (AL, AM) and phase differences between L- and M-cone inputs were estimated.ResultsPerception was always mediated by the P-pathway at low frequencies, as indicated by a median phase angle of 179.84 degrees (cone opponency) and a median AL/AM ratio of 1.04 (balanced L- and M-cone input strengths). In contrast, perception was exclusively mediated by the M-pathway at higher frequencies (input strength not balanced: AL/AM = 2.94, median phase angles = 130.17 degrees). Differences in phase were not significant between diagnosis groups (Kruskal-Wallis = 0.092 for P- and 0.35 for M-pathway). We found differences between groups only for the M-pathway (L-cone tCS deviations at 20 Hz were significantly lower in the patients with glaucoma P = 0.014, with a strong tendency in M-cones P = 0.049). L-cone driven tCS deviations at 20 Hz were linearly correlated with perimetric mean defect (MD) and quadratically correlated with retinal nerve fiber layer (RNFL) thickness.ConclusionsUnaltered phase angles between L- and M-cone inputs in glaucoma indicated intact temporal processing. Only in the M-pathway, contrast sensitivity deviations were closely related to diagnosis group, MD, and RNFL thickness, indicating M-pathway involvement.

Space-vector modulation for three-phase indirect matrix converters to reduce common-mode voltage

This paper presents a space vector modulation strategy for a three-phase indirect matrix converter to reduce the common-mode voltage and maintain the output performance. To reduce the peak value of the common-mode voltage to 57.7% of the input phase voltage, three active voltage vectors are used to generate the desired output voltage with arbitrary amplitude and frequency, instead of using both active and zero voltage vectors as in the traditional space vector modulation strategy. Although the common-mode voltage is reduced, the output waveform quality of the three-phase indirect matrix converter deteriorates due to the absence of the zero voltage vectors. To overcome this problem, the proposed space vector modulation strategy is redesigned to control the rectifier stage of the indirect matrix converter by utilizing three active current vectors instead of two as usual. Consequently, the constant average dc-link voltage is achieved, which can improve the output performance in terms of the output voltage and current harmonic distortion. The simulation is implemented by PSIM software and experimental results are provided to verify the effectiveness of the proposed space vector modulation strategy.

Smart city projects against COVID-19: Quantitative evidence from China

The outbreak of COVID-19 pandemic worldwide has brought huge challenges to urban governance. Whether the smart city projects play a significant role in the COVID-19 prevention and control process is a question worthy of attention. Based on the data of COVID-19 confirmed cases and the smart cities projects investment in China cities, our empirical results show that smart city projects have significantly reduced the number of COVID-19 confirmed cases. Specifically, for every 1 million yuan increase in smart city investment per 10,000 people, the number of COVID-19 confirmed cases per 10,000 people would decrease by 0.342. The heterogeneity analysis results show that the effect of the smart city projects on COVID-19 in the spread phase inside a city is stronger than that in the input phase. In addition, the effect differs for cities with different population sizes. This study provides quantitative evidence of the impact of smart city projects on COVID-19 prevention and control.

A design of 1 to 4 GHz broadband high‐efficiency power amplifier with two‐way concurrent active load modulation method

Active load modulation and harmonic injection can be used to boost the power amplifier's (PA) efficiency, but these techniques must add a fundamental external source or a harmonic generator. In this paper, a two-way power amplifier architecture is introduced to extend high-efficiency operation bandwidth by utilizing concurrent active load modulation with a waveform mapping method. Active load modulation is realized in between the two branches with the aid of independent input amplitude and phase control. Based on a calculated waveform database, high-efficiency operations for both transistors from 1 to 4 GHz are designed in a self-defined optimization platform considering waveform distance and input parameters. Finally, this PA is fabricated and measured to offer 41.6 to 45.0 dBm power, 8.2 to 11.7 dB gain, and 56% to 89% drain efficiency from 0.85 to 3.85 GHz.

A Fully Integrated 47.6% Fractional Bandwidth GaN MMIC Distributed Efficient Power Amplifier With Modified Input Matching and Power Splitting Network

This article presents a fully integrated distributed efficient power amplifier (DEPA) for fifth-generation (5G) massive multiple-input multiple-output (MIMO) applications. In conventional DEPA, an individual input matching network (IMN), power splitter, and phase compensation line are used for each auxiliary power amplifier (PA) unit, resulting in a large overall size. To facilitate integration, an energy-efficient and compact DEPA with modified input matching and power splitting network is proposed, where a distributed input matching network (DIMN) is used for the auxiliary PA. A broadband input matching, reasonable power splitting, and phase alignment can be achieved simultaneously by adjusting the dimensions of gate transmission lines (TLs) between different auxiliary PA units. An integrated DEPA is implemented in a commercial 0.25- μm GaN-HEMT process to validate the proposed architecture. The fabricated DEPA shows a saturated output power of 40.4-41.7 dBm, an 8-dB back-off drain efficiency (DE) of 35%-50%, and a saturated DE of 46%-56% from 3.2 to 5.2 GHz, with a compact size of 3.4×3.0 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Applying a 100-MHz orthogonal frequency division multiplexing (OFDM) signal with a 7.8-dB peak-to-average power ratio (PAPR), an average efficiency of 35.7%-47% is measured over the entire bandwidth, and the adjacent channel power ratio (ACPR) is better than -46 dBc after digital predistortion (DPD). To the best of our knowledge, the proposed DEPA demonstrates the widest bandwidth among all reported fully integrated back-off efficient PAs without using digital techniques or reconfiguration.

Quasi‐phase resolved partial discharge pattern analysis of surface discharges arising on the tar polluted porcelain bushing of an electrostatic precipitator unit under high voltage DC

AbstractThis paper investigates on understanding the DC electrical discharges arising on the surface of feed‐through type indoor bushing with tar depositions. Such information not only provides diagnostic status but also characterizes the multitude of species forming tar depositions which is currently unavailable in literatures. The current practice on analyzing surface discharges initiated under DC voltage employs primitive methods that accounts for the individual discharge events over a larger span rendering it less sensitive and time consuming. The usual practice is to count the discharge events initiated under DC voltage as PD pulses and count the events, repetition rates, time of occurrence, and so forth, to estimate the severity of the fault condition. On contrary, synchronizing these discharge pulses to the phase of the AC voltage, input to the rectifier unit, manifests a pattern, which is time independent and is sensitive in revealing diagnostic status of the bushing. These objectives are initially verified on a sample extracted from a tar polluted bushing. A half‐wave bridge rectifier that produces an uncontrolled positive and negative DC voltage is selected to initiate surface discharges. Pertinent pulses are then correlated to the phase of the AC voltage input to the rectifier and a quasi‐phase resolved partial discharge pattern (QPRPD) is developed. Using this QPRPD pattern, the significance of positive and negative DC voltages applied on the surface of the polluted sample is studied and the inception of discharges events and their correlation to the defect conditions are evaluated. Following this, the pertinent findings are validated on an actual bushing installed in an electrostatic precipitator unit applied for cleaning producer gas generated in a biomass gasification plant.

Students’ Soft Skills, Hard Skills, and Competitiveness (SHC): A Suggested Model for Indonesian Higher Education Curriculum

This study develops a model for students and graduates of Soft Skills, Hard Skills, and Competitiveness (SHC) and seeks user validation after the development process. The development process uses the Analysis, Design, Development, Implementation, and Evaluation (ADDIE) model. A quantitative survey using questionnaires and descriptive quantitative analysis was applied in obtaining user validation as the study objective. The development results validated the students' SHC Development model, which has 3 main phases, including Input, Process and Output. The Input phase comprises course content, SHC component, and strategy of students’ center approach. The Process phase consists of blended course design, instruction and students' engagement, and evaluation. The Output phase comprises soft and hard skills achievement, as well as students’ competitiveness level. Users perceived the model’s phases and components as wholly acceptable, appropriate, and applicable for implementation through curriculum, teaching, and learning at the university. This study contributes to graduate preparation for employability skills in the challenging and complex working environment in revolution industry 4.0.

Medial olivocochlear reflex effects on amplitude growth functions of long- and short-latency components of click-evoked otoacoustic emissions in humans.

Functional outcomes of medial olivocochlear reflex (MOCR) activation, such as improved hearing in background noise and protection from noise damage, involve moderate to high sound levels. Previous noninvasive measurements of MOCR in humans focused primarily on otoacoustic emissions (OAEs) evoked at low sound levels. Interpreting MOCR effects on OAEs at higher levels is complicated by the possibility of the middle-ear muscle reflex and by components of OAEs arising from different locations along the length of the cochlear spiral. We overcame these issues by presenting click stimuli at a very slow rate and by time-frequency windowing the resulting click-evoked (CE)OAEs into short-latency (SL) and long-latency (LL) components. We characterized the effects of MOCR on CEOAE components using multiple measures to more comprehensively assess these effects throughout much of the dynamic range of hearing. These measures included CEOAE amplitude attenuation, equivalent input attenuation, phase, and slope of growth functions. Results show that MOCR effects are smaller on SL components than LL components, consistent with SL components being generated slightly basal of the characteristic frequency region. Amplitude attenuation measures showed the largest effects at the lowest stimulus levels, but slope change and equivalent input attenuation measures did not decrease at higher stimulus levels. These latter measures are less commonly reported and may provide insight into the variability in listening performance and noise susceptibility seen across individuals.NEW & NOTEWORTHY The auditory efferent system, operating at moderate to high sound levels, may improve hearing in background noise and provide protection from noise damage. We used otoacoustic emissions to measure these efferent effects across a wide range of sound levels and identified level-dependent and independent effects. Previous reports have focused on level-dependent measures. The level-independent effects identified here may provide new insights into the functional relevance of auditory efferent activity in humans.

Adaptive beam clean-up of high power slab lasers using least-squares wavefront reconstruction algorithm with performance-based filtering

The edge effects of high-power slab lasers cause severe wavefront distortions with large amplitude and gradients, which is a great challenge for the adaptive optics systems for improving the beam qualities. The standard least-squares wavefront reconstruction method would inherently assign higher priorities to correcting the edge aberrations which contribute little to the laser power in the near diffraction-limit areas in the far-field, while the other aberrations are not well corrected. To solve the problems, we propose a least-squares reconstruction algorithm with performance-based filtering, in which the correction capability of the deformable mirror is analyzed in the spatial frequency domain, and then the input phase distortions are filtered accordingly. The uncorrectable components of input distortions are ignored so that the residuals of the correctable components could be further minimized. Experiments with a 20 kW Nd:YAG slab laser indicate that the proposed method is effective to improve the beam quality of high-power slab laser with edge effect.

Discontinuous Conduction Mode Analysis of High Gain Extended-Duty-Ratio Boost Converter

A typical non-isolated photovoltaic (PV) microinverter requires a high conversion ratio in the dc-dc stage as well as needs to support a wide range of input-output voltage operation accommodating partial shading scenario. An extended-duty-ratio (EDR) boost converter is a good candidate for such application as it provides a high efficiency solution with a hybrid of interleaved inductor and switched capacitor configuration significantly lowering the switch voltage stress, switching losses, and providing inherent equal current sharing among the input phases. However, these advantages of EDR boost converter in continuous conduction mode (CCM) is only true for a limited duty ratio range. On the contrary, it is observed that the discontinuous conduction mode (DCM) can support a wider range of duty ratio operation, maintaining lower voltage stress on the devices and ensuring inherent equal current sharing among the boost inductors. Nevertheless, even in the DCM, the operation in the region with least voltage gain becomes very complex and requires a thorough understanding. This paper presents an extensive analysis of an EDR boost converter for DCM operation for all the operating regions. The operating characteristics of an EDR boost converter in DCM is analysed and its gain is derived. The detailed analysis presented in this paper enables in designing the components and judiciously deciding the operating range of EDR boost converter in DCM operation for any application. In order to verify the analysis, the simulation and experimental results from a 300 W EDR boost hardware prototype are also provided.

Система прямого керування струмом активного фільтра

The main direction of research is the optimization of the active filter, simplification of the control system and the identification of new algorithms for calculating the compensating currents. There has been improved the direct current control system of active filter with the formation of sinusoidal signals equal to the fundamental harmonic of phase load currents, as well as non-sinusoidal asymmetric signals, as the difference between input phase currents of load and fundamental harmonics, to filter higher harmonics and balancing currents filtering of higher harmonics and balancing of nonlinear asymmetric loads. The control system, which consists of two units: the unit for generating the current compensation of higher harmonics and the unit for converting currents from the phase coordinate system to the coordinate system of instantaneous symmetrical components, provides almost complete compensation for linear and nonlinear distortion. In the case of using one unit for converting currents from the phase coordinate system to the coordinate system of instantaneous symmetrical components, which significantly simplifies the implementation of the control system, provides sufficient for mass consumers quality compensation of higher harmonics (provides compensation of the third, fifth, seventh and ninth current harmonics , and the level of uncompensated higher harmonics is determined by the eleventh and thirteenth harmonics, the content of which is significantly lower) and full load balancing. It is shown that the system of direct current control of the active filter in the case of using the vector of phase currents and the vector of phase voltages can be used for full compensation of reactive power. In this case, there is a slight initial overregulation of the reactive power, which is automatically compensated. The reactive power is regulated indirectly by the voltage support circuit on the capacitor of the active filter voltage inverter.

DEVELOPMENT OF NEURAL THERMAL SCATTERING (NeTS) MODULES FOR REACTOR MULTI-PHYSICS SIMULATIONS

Modern multi-physics codes, often employed in the simulation and development of thermal nuclear systems, depend heavily on thermal neutron interaction data to determine the space-time distribution of fission events. Therefore, the computationally expensive analysis of such systems motivates the advancement of thermal scattering law (TSL) data delivery methods. Despite considerable improvements on past strategies, current implementations are limited by trade-offs between speed, accuracy, and memory allocation. Furthermore, many of these implementations are not easily adaptable to additional input parameters (e.g., temperature), relying instead on various interpolation schemes. In this work, a novel approach to this problem is demonstrated with a neural network trained on beryllium oxide thermal scattering data generated by theFLASSHnuclear data code of the Low Energy Interaction Physics (LEIP) group at North Carolina State University. Using open-source deep learning libraries, this approach maps a unique functional form to theS(α,β,T) probability distribution function, providing a continuous representation of the TSL across the input phase space. For a given material, the result is a highly accurate, neural thermal scattering (NeTS) module that enables rapid sampling and execution with minimal memory requirements. Moreover, extension of the NeTS phase space to other parameters of interest (e.g., pressure, radiation damage) is highly possible. Consequently, NeTS modules for different materials under various conditions can be stored together in material “lockers” and accessed on-the-fly to generate problem specific cross-sections.

Delayed flow is a risk to patient safety: A mixed method analysis of emergency department patient flow

IntroductionIncreasing emergency department (ED) demand and crowding has heightened focus on the need for better understanding of patient flow. AimThis study aimed to identify input, throughput and output factors contributing to ED patient flow bottlenecks and extended ED length of stay (EDLOS). MethodConcurrent nested mixed method study based on retrospective analysis of attendance data, patient flow observational data and a focus group in an Australian regional ED. ResultsAnalysis of 89 013 ED presentations identified increased EDLOS, particularly for patients requiring admission. Mapping of 382 patient journeys identified delays in time to triage assessment (0–39 mins) and extended waiting room stays (0–348 mins). High proportions of patients received care outside ED cubicles. Four qualitative themes emerged: coping under pressure, compromising care and safety, makeshift spaces, and makeshift roles. ConclusionThree key findings emerged: i) hidden waits such as extended triage-queuing occur during the input phase; ii) makeshift spaces are frequently used to assess and treat patients during times of crowding; and iii) access block has an adverse effect on output flow. Data suggests arrival numbers may not be a key predictor of EDLOS. This research contributes to our understanding of ED crowding and patient flow, informing service delivery and planning.

Real-time assessment of potential peak local specific absorption rate value without phase monitoring: Trigonometric maximization method for worst-case local specific absorption rate determination.

PurposeMulti‐transmit MRI systems are typically equipped with dedicated hardware to sample the reflected/lost power in the transmit channels. After extensive calibration, the amplitude and phase of the signal at the feed of each array element can be accurately determined. However, determining the phase is more difficult and monitoring errors can lead to a hazardous peak local specific absorption rate (pSAR10g) underestimation. For this purpose, methods were published for online maximum potential pSAR10g estimation without relying on phase monitoring, but these methods produce considerable overestimation. We present a trigonometric maximization method to determine the actual worst‐case pSAR10g without any overestimation.Theory and MethodThe proposed method takes advantage of the sinusoidal relation between the SAR10g in each voxel and the phases of input signals, to return the maximum achievable SAR10g in a few iterations. The method is applied to determine the worst‐case pSAR10g for three multi‐transmit array configurations at 7T: (1) body array with eight fractionated dipoles; (2) head array with eight fractionated dipoles; (3) head array with eight rectangular loops. The obtained worst‐case pSAR10g values are compared with the pSAR10g values determined with a commonly used method and with a more efficient method based on reference‐phases.ResultsFor each voxel, the maximum achievable SAR10g is determined in less than 0.1 ms. Compared to the reference‐phases‐based method, the proposed method reduces the mean overestimation of the actual pSAR10g up to 52%, while never underestimating the true pSAR10g.ConclusionThe proposed method can widely improve the performance of parallel transmission MRI systems without phase monitoring.

Remote Control, Protection and Monitoring of Pump for Agricultural Purposes

With the increasing pressure on our natural resources and diminishing soil quality, there is a need to make better efforts to conserve them. This project aims to help control the irrigation in a small field. The motor pump set equipped at the field is prone to a variety of operational issues like Power Quality issues, Reverse run of the pump, Irregular Power Supply. Using an ATMEGA Microcontroller equipped with GSM Module for connectivity, this model is able to provide the user with remote control for the motor pump set equipped at his field. Additionally, this model comes with protection schemes for detection of Input Phase Sequence Supply and protection against Over Voltage and Over Current. This system aims to reduce the man power requirement in the field by providing remote or at home control of the pump set applied on the field with cost effective and easy control which can be used by unskilled operators as well.

Accelerating triangle-like singular beam

We demonstrate a type of singular beam that accelerates along a parabolic trajectory and has a cross-section intensity pattern exhibiting a dark central region surrounded by multiple rings with the innermost (main) ring resembling an equilateral triangle. The key to creating such beams is to replace the standard triangle with a rounded one, made up of six circular arcs connected end to end. The individual input phase mask for each arc can be analytically computed, and the whole input phase mask for the beam is thus obtained by piecing together these individual phases. Furthermore, the continuity of field forces of these triangle-like modes is discrete; that is, an index similar to the topological charge of vortex beams arises. Numerical results show that the energy flow in the beam's cross section circulates around the dark center along the triangle-like main ring, suggesting a possible application in orbiting particles along an irregular path.

In Silico Study on Tumor-Size-Dependent Thermal Profiles inside an Anthropomorphic Female Breast Phantom Subjected to Multi-Dipole Antenna Array.

Electromagnetic hyperthermia as a potent adjuvant for conventional cancer therapies can be considered valuable in modern oncology, as its task is to thermally destroy cancer cells exposed to high-frequency electromagnetic fields. Hyperthermia treatment planning based on computer in silico simulations has the potential to improve the localized heating of breast tissues through the use of the phased-array dipole applicators. Herein, we intended to improve our understanding of temperature estimation in an anatomically accurate female breast phantom embedded with a tumor, particularly when it is exposed to an eight-element dipole antenna matrix surrounding the breast tissues. The Maxwell equations coupled with the modified Pennes’ bioheat equation was solved in the modelled breast tissues using the finite-difference time-domain (FDTD) engine. The microwave (MW) applicators around the object were modelled with shortened half-wavelength dipole antennas operating at the same 1 GHz frequency, but with different input power and phases for the dipole sources. The total input power of an eight-dipole antenna matrix was set at 8 W so that the temperature in the breast tumor did not exceed 42 °C. Finding the optimal setting for each dipole antenna from the matrix was our primary objective. Such a procedure should form the basis of any successful hyperthermia treatment planning. We applied the algorithm of multi for multi-objective optimization for the power and phases for the dipole sources in terms of maximizing the specific absorption rate (SAR) parameter inside the breast tumor while minimizing this parameter in the healthy tissues. Electro-thermal simulations were performed for tumors of different radii to confirm the reliable operation of the given optimization procedure. In the next step, thermal profiles for tumors of various sizes were calculated for the optimal parameters of dipole sources. The computed results showed that larger tumors heated better than smaller tumors; however, the procedure worked well regardless of the tumor size. This verifies the effectiveness of the applied optimization method, regardless of the various stages of breast tumor development.

An Improved Three-Phase Buck Rectifier With Low Voltage Stress on Switching Devices

An improved three-phase buck rectifier (3ph-BR) with low voltage stress on switching devices is proposed in this letter. In the conventional 3ph-BR, the voltage stress on MOSFET s is higher than the amplitude of input phase voltage. However, in the proposed 3ph-BR, the voltage stress on MOSFET s is lower than the amplitude of input phase voltage, which results in reduction of voltage stress on MOSFET s. Therefore, the cost-efficient and low voltage rating MOSFET s with low on-resistance can be utilized, which makes the proposed 3ph-BR suitable for applications that require high-efficiency and high-density. A 1.5-kW experimental prototype of the proposed rectifier is built to verify the analysis results.

NKCC-1 mediated Cl\u2212 uptake in immature CA3 pyramidal neurons is sufficient to compensate phasic GABAergic inputs

Activation of GABAA receptors causes in immature neurons a functionally relevant decrease in the intracellular Cl− concentration ([Cl−]i), a process termed ionic plasticity. Amount and duration of ionic plasticity depends on kinetic properties of [Cl−]i homeostasis. In order to characterize the capacity of Cl− accumulation and to quantify the effect of persistent GABAergic activity on [Cl−]i, we performed gramicidin-perforated patch-clamp recordings from CA3 pyramidal neurons of immature (postnatal day 4–7) rat hippocampal slices. These experiments revealed that inhibition of NKCC1 decreased [Cl−]i toward passive distribution with a time constant of 381 s. In contrast, active Cl− accumulation occurred with a time constant of 155 s, corresponding to a rate of 15.4 µM/s. Inhibition of phasic GABAergic activity had no significant effect on steady state [Cl−]i. Inhibition of tonic GABAergic currents induced a significant [Cl−]i increase by 1.6 mM, while activation of tonic extrasynaptic GABAA receptors with THIP significantly reduced [Cl−]i.. Simulations of neuronal [Cl−]i homeostasis supported the observation, that basal levels of synaptic GABAergic activation do not affect [Cl−]i. In summary, these results indicate that active Cl−-uptake in immature hippocampal neurons is sufficient to maintain stable [Cl−]i at basal levels of phasic and to some extent also to compensate tonic GABAergic activity.

Adaptive leakage signal cancellation algorithm in heterodyne FMCW system

To mitigate the leakage signal that obstructs the target information extraction in miniatured frequency modulated continuous wave (FMCW) radar system, an adaptive leakage signal cancellation algorithm is proposed in this paper. Without any help of the additional auxiliary path, all the processing for the intermediate frequency (IF) signal can be conducted in the digital domain. The basic principle to cancel leakage signal is to produce a cancelling signal, which has the same amplitude and anti-phase with the leakage signal. Differently, in this paper, the input phase parameter of the proposed method can be arbitrary and it can be modified by the corresponding corrected function. Besides, to acquire the phase noise in the leakage signal conveniently when generating cancelling signal, the information geometry theory is applied to transform the complex phase noise model into statistical characteristics calculation of the input signal. The effectiveness of the model and the proposed algorithm is verified by simulated results. Furthermore, a real FMCW system is designed to collect the practice echo signals. The resulting data denotes that the leakage signal in the received signal is greatly suppressed and the leakage signal power drops by −15.92 dB.