bluuebunny/crossref_metadata_2025_split huggingface dataset:
Closed‐loop input current control strategy based on waveform similarity index for the emerging matrix converters with harmonic injection technique
Authors: Yang Zhichao , Lei Jiaxing , Gao Bingtuan , Chen Wu 
Published: January 2025

AbstractHarmonic injection matrix converter (HIMC) achieves direct AC‐AC power conversion with maximum voltage transfer and reduced transistor capacity. However, the existing open‐loop current control method for HIMC may bring in low‐order harmonics if the injected harmonic current deviates from its desired value. To address this issue, this paper proposes a closed‐loop input current control strategy based on the waveform similarity index (WSI) for these emerging MC topologies. The WSIs are defined as the ratios of the corresponding input currents against the maximum and minimum input voltages. Multi resonant controllers are adopted to regulate the WSI difference so that its low‐order harmonics are eliminated, which generate an additional signal to correct the injected harmonic current. By adopting the proposed current control strategy, the 5th and 7th harmonics are suppressed to lower than 1.0% under the sinusoidal input voltages and nominal load scenario. Even with inaccuracies in the reference harmonic current generation, the proposed strategy enables the input currents to approach sinusoidal waveforms with significantly reduced WSIs difference, thus enhancing the input power factor over the conventional open‐loop method. Besides, the proposed method is effective under unbalanced and distorted conditions through the experimental verification.
Comprehensive analysis of admittance matrix estimation considering different noise models
Authors: de Albuquerque Felipe Proença , Lemes Francisco Rodrigues , Nascimento Rafael , Costa Eduardo C. Marques , Caballero Pablo Torrez 
Published: January 2025

AbstractThe previous knowledge of the admittance matrix represents an important issue in power system analysis, specifically regarding load flow, voltage stability, and protection setting. Some parameter estimation techniques in technical literature determine the admittance matrix of electric power grids, leading to notable advances in measurement and monitoring. This paper proposes a robust approach to determine the admittance matrix using deep learning techniques. Throughout the paper, results demonstrate that the proposed approach handles Gaussian and non‐Gaussian noise reliably, outperforming other works in the technical literature. This paper also evaluates the proposed method in several scenarios, including different numbers of samples and varying noise level, as well as loads with non‐linear variations. The proposed method has low computational complexity because it considers only a few features while estimating admittance parameters. Results demonstrate that the proposed approach sustains accuracy and robustness, even when subjected to high noise levels in the measurements. This paper evaluates the proposed approach by estimating the parameters of the IEEE 14‐bus and 57‐bus systems and presents the performance of all parameters for the 14‐bus system.
Reliability and validity of computer vision‐based markerless human pose estimation for measuring hip and knee range of motion
Authors: Hellstén Thomas , Arokoski Jari , Karlsson Jonny , Ristolainen Leena , Kettunen Jyrki 
Published: January 2025

AbstractTelerehabilitation requires accurate joint range of motion (ROM) measurement methods. The aim of this study was to evaluate the reliability and validity of a computer vision (CV)‐based markerless human pose estimation (HPE) application measuring active hip and knee ROMs. For this study, the joint ROM of 30 healthy young adults (10 females, 20 males) aged 20–33 years (mean: 22.9 years) was measured, and test–retests were assessed for reliability. For validity evaluation, the CV‐based markerless HPE application used in this study was compared with an identical reference picture frame. The intraclass correlation coefficient (ICC) for the CV‐based markerless HPE application was 0.93 for active hip inner rotation, 0.83 for outer rotation, 0.82 for flexion, 0.82 for extension, and 0.74 for knee flexion. Correlations (r) of the two measurement methods were 0.99 for hip‐active inner rotation, 0.98 for outer rotation, 0.87 for flexion, 0.85 for extension, and 0.90 for knee flexion. This study highlights the potential of a CV‐based markerless HPE application as a reliable and valid tool for measuring hip and knee joint ROM. It could offer an accessible solution for telerehabilitation, enabling ROM monitoring.
Future prospects for measuring 1PPN parameters using observations of S2 and S62 at the Galactic center
Authors: de Mora Losada Victor , Della Monica Riccardo , de Martino Ivan , De Laurentis Mariafelicia 
Published: January 2025

Context. The parameterized post-Newtonian (PPN) formalism offers an agnostic framework for evaluating theories of gravity that extend beyond general relativity. Departures from general relativity are represented by a set of dimensionless parameters that, at the first order in the expansion, reduce to β and γ, which describe deviations in spatial curvature and nonlinear superposition effects of gravity, respectively.
Aims. We exploit future observations of stars at the Galactic center, orbiting the supermassive black hole Sagittarius A*, to forecast the ability to constrain the first-order PPN parameters γ and β.
Methods. We have generated a mock catalog of astrometric and spectroscopic data for S2, based on the Schwarzschild metric, simulating observations over multiple orbital periods with the GRAVITY and SINFONI instruments. Our analysis includes the effects of relativistic orbital precession and line-of-sight velocity gravitational redshift. Since future data for S2 can only provide constraints on a linear combination of the PPN parameters β and γ, we also analyzed the impact of future observations of the gravitational lensing on stars that pass closer in the sky to Sgr A*, such as the known star S62, which can potentially provide tight constraints on the parameter γ, which alone regulates the amplitude of the astrometric deviations due to lensing.
Results. When combining lensing observations for S62, and the precise orbital tracking of S2, one obtains independent constraints on both γ (with a potential precision as good as and β (with a corresponding precision of ~2%), providing a precision test of general relativity and its extensions.
Horizontal flows in the atmospheres of chemically peculiar stars
Authors: ud-Doula A. , Krtička J. , Kubátová B. 
Published: January 2025

Context. Classical chemically peculiar stars exhibit atmospheres that are often structured by the effects of atomic diffusion. As a result of these elemental diffusion and horizontal abundance variations, the photospheric temperature varies at a given height in the atmosphere. This may lead to horizontal flows in the photosphere. In addition, the suppression of such flows by a magnetic field can alter the elemental transport processes.
Aims. Using a simplified model of such a structured atmosphere and 2D magnetohydrodynamic simulations of a typical He-rich star, we examined atmospheric flows in these chemically peculiar stars, which often are strongly magnetic.
Methods. We used Zeus-MP, which is a publicly available Fortran 90-based parallel finite element modular code.
Results. We find that for non-magnetic stars of spectral type BA, the atmospheric flow related to the horizontal temperature gradient can reach 1.0 km s−1, yielding mixing timescales of the order of tens of days. For the magnetic counterparts, the flow speeds are an order of magnitude lower, allowing for the stratification of chemical elements.
Conclusions. Magnetic fields can significantly influence the dynamics in atmospheres. A strong horizontal magnetic field inhibits flow in the vertical direction, while a strong vertical magnetic field can suppress horizontal atmospheric flow and prevent elemental mixing.
Repeated pattern of γ-ray flares in the blazar PKS 1502+106 coincident with the IC190730A neutrino event
Authors: Blinov Dmitry , Novikova Polina 
Published: January 2025

Context. It has been demonstrated that at least 10% of the brightest blazars in the fourth Fermi-LAT catalog of γ-ray sources exhibit repeating patterns of γ-ray flares. These events may be associated with the presence of a non-uniform sheath surrounding a fast jet spine in some blazars. Theoretical models suggest that such a sheath could facilitate neutrino production in these structured jets.
Aims. We aim to test the marginal statistical evidence previously reported for a connection between repeating patterns of γ-ray flares in blazars and high-energy neutrino events that are positionally consistent with these sources.
Methods. We identified a repeating pattern of flares in the γ-ray light curve of the blazar PKS 1502+106, which lies within the 50% uncertainty region of the IC190730A neutrino candidate event. This occurrence is combined with two other high-energy (≥200 TeV) neutrino events from ICECAT-1, which arrived in both positional and temporal coincidence with two blazars exhibiting ongoing repeating flare patterns. We conducted a Monte Carlo simulation to evaluate the likelihood of accidental coincidences between the repeating flare patterns and neutrino events, accounting for potential unrecognized systematic uncertainties in the arrival directions of the ICECAT-1 events.
Results. Our findings indicate the probability of a random coincidence, in both time and arrival direction for three high-energy neutrino candidates and three blazars with ongoing recurring patterns of γ-ray flares, is 1.56 × 10−3 (3.2σ).
Half-time range description for the free space wave operator and the spherical means transform
Authors: Kuchment P , Kunyansky L 
Published: January 2025

Abstract
The forward problem arising in several hybrid imaging modalities can be modeled by the Cauchy problem for the free space wave equation. Solution to this problems describes propagation of a pressure wave, generated by a source supported inside unit sphere S. The data g represent the time-dependent values of the pressure on the observation surface S. Finding initial pressure f from the known values of g consitutes the inverse problem. The latter is also frequently formulated in terms of the spherical means of f with centers on S. Here we consider a problem of range description of the wave operator mapping f into g. Such a problem was considered before, with data g known on time interval at least

[
0
,
2
]

(assuming the unit speed of sound). Range conditions were also found in terms of spherical means, with radii of integration spheres lying in the range

[
0
,
2
]

. However, such data are redundant. We present necessary and sufficient conditions for function g to be in the range of the wave operator, for g given on a half-time interval

[
0
,
1
]

. This also implies range conditions on spherical means measured for the radii in the range

[
0
,
1
]

.
WR-3 wideband waveguide diplexers based on the perfectly symmetric Y-junction
Authors: Ding Jiangqiao , Jiang Luying , Lei Yalin , Zhao Yun , Li Sheng , Wang Caixia , Jiang Jun 
Published: January 2025

Abstract
In this work, two WR-3 band waveguide diplexers based on symmetrical H-plane and E-plane Y-junctions are developed, fabricated, and compared to highlight bandwidth performance. Both symmetrical H-plane and E-plane Y-junctions are first analyzed to determine the conditions for implementing wideband waveguide diplexers. Then a mid-band H-plane diplexer-I and a wideband E-plane diplexer-II are designed and demonstrated through CNC-milling technology. The measured results of H-plane diplexer-I show central frequencies of 251.5 GHz and 294 GHz, 3 dB fractional bandwidths (FBWs) of 5.6% and 3.3%, as well as insertion losses (ILs) of about 2 dB. The practical E-plane waveguide diplexer-II has achieved central frequencies of 264.5 GHz and 309 GHz, 3 dB FBWs of 11.4% and 6.2%, low ILs of 1.5 dB, as well as high isolation exceeding 50 dB. All the measured performance agree well with the simulation, verifying that the symmetrical E-pane Y-junction is optimal for the wideband waveguide diplexer. Additionally, such compact and scalable THz waveguide diplexers for future transceivers can meet the current CNC manufacturing constraints.
Enhancing photodetector performance via interlayer energy transfer in 2D hybrid perovskite heterostructures
Authors: Han Bin , Tang Yanren , Qiu Qi , Lian Bingtao , Liu Bo , Ding Shukai , Ma Shufang , Li Guoqiang , Xu Bingshe , Hsu Hsien-Yi 
Published: January 2025

Abstract
Two-dimensional (2D) organic–inorganic hybrid perovskites (OIHPs) have emerged as promising materials for optoelectronic devices due to their exceptional properties. However, their application is often hindered by limited charge transfer (CT) capabilities, attributed to the insulating organic spacer layers. In this study, we address this challenge by introducing a BA2MA2Pb3I10/PEA2MA2Pb3I10 heterostructure, which leverages interlayer energy transfer (ET) to overcome CT limitations. This ET mechanism leads to a substantial enhancement in photoluminescence (PL) emission, with the heterostructure displaying a ∼2.4-fold increase in PL intensity compared to pristine PEA2MA2Pb3I10. Additionally, encapsulating the heterostructure boosts PL emission by 5.2 times. The impact of ET on device performance was further demonstrated in photodetectors based on this heterostructure. These devices exhibited significant improvements in photoresponse, achieving a maximum responsivity of 10 A W−1, which are almost 10 times greater than those of devices fabricated from the individual BA2MA2Pb3I10 and PEA2MA2Pb3I10 devices. Additionally, the heterostructure device demonstrates rapid response times, with a rise time of 7 ms and a decay time of 4 ms, significantly outperforming both the pure BA2MA2Pb3I10 device (450 ms rise, 470 ms decay) and the PEA2MA2Pb3I10 device (350 ms rise, 370 ms decay). These findings highlight ET as an effective strategy for enhancing the optoelectronic performance of 2D OIHP-based devices, paving the way for high-efficiency applications in future photodetectors and other optoelectronic technologies.
Structural diversity and electronic properties of neodymium borides under high pressure
Authors: Sun Weiguo , Li Xiaofeng , Zhang Chuanzhao , Ju Meng 
Published: January 2025

Abstract
Rare earth (RE) borides have garnered significant attention due to their high mechanical strength, superconductivity, and novel electronic properties. In this study, we systematically investigate the structural, electronic, and mechanical properties of RE neodymium borides across a wide range of pressures. Various stoichiometries of Nd–B compounds are predicted using the unbiased CALYPSO structure search method and density functional theory calculations. Our findings indicate that the newly predicted NdB5, NdB7, and NdB8 compounds are thermodynamically and mechanically stable at high pressures. Detailed analyses of the electronic band structure and density of states reveal that all neodymium borides exhibit metallic behaviour. The hardness of the stable phases has been evaluated using an empirical model. Notably, NdB5 compound could also be dynamically and mechanically stable at ambient pressure with an estimated hardness of approximately 24.82 GPa, suggesting that NdB5 is a potential hard metal boride. Our results provide valuable insights into the structural, electronic, and mechanical properties of Nd–B compounds, enhancing our understanding of their potential applications in various fields.
Human fall detection based on adaptive local region-duration features using MIMO radar
Authors: Lin Jinhong , Yang Zhaocheng , Chu Ping , Lian Tongsheng , Zhou Jianhua 
Published: January 2025

Abstract
The existing radar-based human fall detection methods mostly consider relatively simple fall actions, overlooking the complexity of actual human falls involving different postures and speeds. Additionally, the dynamic changes in household items such as electric fans and curtains in real indoor environments can affect the performance of fall detection. To address these problems, we propose a human fall detection approach based on adaptive local region-duration features using multi-input multi-output radar. We first utilize multiple target detection and tracking to obtain target trajectory information. Then, we select local region and extract multidimensional dynamic sequences of targets based on their trajectory information. Finally, we adaptively intercept corresponding information sequences through suspicious fall event detection and extract adaptive local region-duration features for the classification of fall and non-fall events. The experimental results show that the proposed approach is capable of detecting various complex fall actions with different durations. Moreover, the proposed approach achieves an average accuracy of 98.2% and 98.0% in the absence and presence of interference, respectively.
Anatomy-wise lung ventilation imaging for precise functional lung avoidance radiation therapy
Authors: Chen Zhi , Li Zihan , Huang Yu-Hua , Teng Xinzhi , Zhang Jiang , Xiong Tianyu , Dong Yanjing , Song Liming , Ren Ge , Cai Jing 
Published: January 2025

Abstract

Objective. This study aimed to propose a method for obtaining anatomy-wise lung ventilation image (VIaw) that enables functional assessment of lung parenchyma and tumor-blocked pulmonary segments. The VIaw was used to define multiple functional volumes of the lung and thereby support radiation treatment planning. Approach. A super-voxel-based method was employed for functional assessment of lung parenchyma to generate VIsvd. In the VIsvd of the 11 patients with tumor blockage of the airway, the functional value in tumor-blocked segments was set to 0 to generate the VIaw. The lung was divided into regions of high functional volume (HFV), unrecoverable low functional volume (LFV), and recoverable LFV (rLFV, the region in the tumor-blocked segment with a high function value based on the VIsvd) to design three intensity-modulated photon plans for five patients. These plans were an anatomical-lung-guided plan (aPlan), a functional-lung-guided plan (fPlan), and a recoverable functional-lung-guided plan (rfPlan) where the latter protected both HFV and rLFV. Main results. The LFV in the reference ventilation images and the tumor-blocked segments had a high overlap similarity coefficient value of 0.90 ± 0.07. The mean Spearman correlation between the VIaw and reference ventilation images was 0.72 ± 0.05 for the patient with tumor blockage of the airway. The V20 and mean dose of rLFV in rfPlan were lower than those in aPlan by 12.1 ± 8.4% and 13.0 ± 6.4%, respectively, and lower than those in fPlan by 14.9 ± 9.8% and 15.9 ± 6.5%, respectively. Significance. The VIaw can reach a moderate-strong correlation with reference ventilation images and thus can identify rLFV to support treatment planning to preserve lung function.
Antenna miniaturization and application in-band interference reduction using dipole array mirror reflector FSS for Sub 6 GHz applications
Authors: Ara Shabnam , Prasanthi Kumari Nunna , Varshney Atul 
Published: January 2025

Abstract
This work contributes a compact FSS antenna novel dual-band miniaturized planar antenna for 5G Sub 6 GHz implementations and its design considered the challenge of designing an antenna with reduced dimensions, which in turn is expected to be more cost-effective to produce and exhibit lower interferences compared to existing market solutions. The low-loss double-layered miniaturized rectangular microstrip antenna consists a dipole strip array mirror reflector frequency selective surface (FSS) layer beneath the antenna ground at an optimized gap that makes the antenna multi-layered and improves its directional radiation characteristics. The existing antennas are based on the same principle of Fabry–Perot cavity interference and achieve ultra-wideband (UWB) bandwidth with a larger substrate size. Therefore, they have in-band applications interferences issues with 5G. These issues are remedies by reduction in the UWB bandwidth and substrate size miniaturization trade-off. A 74.11% antenna size miniaturization is achieved with a 47.6% reduction in the –10 dB bandwidth in comparison to the base antenna of size 49 × 49 mm2. The introduced notch-band (5.63–5.85 GHz) bifurcate the UWB bandwidth. Therefore, the notch band works as the boundary between the extra-applications bands (5.85–8.62 GHz) and 5G applications band (1.70–5.63 GHz) and eliminates in-band applications interferences. The overall volume of the 3D antenna is controlled by optimizing the two substrates gap. A parametric study of the modified miniaturized antenna dimensions has been conducted, and the simulation results were validated through experimental measurements. Since the antenna covers almost FR1 (1.0–6.0 GHz) range, therefore, it is the most appropriate candidate for all 5G bands including the main n77 (3.3–4.2 GHz), n78 (3.3–3.8 GHz), and n79 (4.4–5.0 GHz), Global System for Mobile Communication, Personal Communication Services (PCS), Wi-Fi/WLAN/Bluetooth, Wi-MAX (3.5 GHz), HiperLAN (5.8 GHz), C-band (5.85–8.0 GHz), and Lower 6G band (7.125–8.40 GHz) applications.
Ab-initio study of anomalous Hall and Nernst effects in equiatomic quaternary heusler alloy CoFeVGe
Authors: Pradhan Ripan , Rana Monika , Sharma Anurodh , Pathipati Srinivasa Rao , Turpu G R , Das Pradip , Lingam Chittari Bheema , Rambabu P 
Published: January 2025

Abstract
First-principles calculations were performed to investigate the electronic, magnetic, and topological properties of the nearly half-metallic ferromagnetic Heusler alloy CoFeVGe. The compound was found to exhibit mechanical and dynamical stability. We conducted a comprehensive study of the anomalous Hall and Nernst effects, attributed to Berry curvature induced by spin–orbit coupling (SOC). The maximum anomalous Hall conductivity (AHC) and anomalous Nernst conductivity (ANC) were determined to be −340.2S/m and −1.26Am−1 K−1 at 300 K, respectively, within an energy window of ±300meV around the Fermi level E

F
. The temperature and chemical potential dependence of the anomalous Nernst conductivity was also explored. The Curie temperature (T

c
), estimated using mean-field approximation and magnetic Heisenberg exchange interactions, was found to be 489.3K. Additionally, magneto-optical Kerr effect calculations yielded a maximum polar Kerr angle of 0.19∘. Our results suggest that CoFeVGe is a promising candidate for spintronic and magneto-optical applications.
Invariant measures for some dissipative systems from the Jacobi last multiplier
Authors: Ghosh Aritra 
Published: January 2025

Abstract
Hamiltonian dynamics describing conservative systems naturally preserves the standard notion of phase-space volume, a result known as the Liouville’s theorem which is central to the formulation of classical statistical mechanics. In this paper, we obtain explicit expressions for invariant phase-space measures for certain (generally dissipative) mechanical systems, namely, systems described by conformal vector fields on symplectic manifolds that are cotangent bundles, contact Hamiltonian systems, and systems of the Liénard class. The latter class of systems can be described by certain generalized conformal vector fields on the cotangent bundle of the configuration space. The computation of the invariant measures is achieved by making use of the formalism of Jacobi last multipliers.