bluuebunny/crossref_metadata_2025_split huggingface dataset:
Learning‐based control for discrete‐time constrained nonzero‐sum games
Authors: Mu Chaoxu , Peng Jiangwen , Tang Yufei 
Published: March 2021

AbstractA generalized policy‐iteration‐based solution to a class of discrete‐time multi‐player non‐zero‐sum games concerning the control constraints was proposed. Based on initial admissible control policies, the iterative value function of each player converges to the optimum approximately, which is structured by the iterative control policies satisfying the Nash equilibrium. Afterwards, the stability analysis is shown to illustrate that the iterative control policies can stabilize the system and minimize the performance index function of each player. Meanwhile, neural networks are implemented to approximate the iterative control policies and value functions with the impact of control constraints. Finally, two numerical simulations of the discrete‐time two‐player non‐zero‐sum games for linear and non‐linear systems are shown to illustrate the effectiveness of the proposed scheme.
Intelligent hybrid automatic repeat request retransmission for multi‐band Wi‐Fi networks
Authors: Wang Zhou , Fang Xuming , Yan Li , He Rong , Long Yan 
Published: March 2021

AbstractWith the increase of Wi‐Fi connections and throughput, the problems posed by unreliable connection and unstable delay need to be urgently solved through advanced methods. The IEEE 802.11ax standard was designed to improve the reliability of connection and increase the throughput in dense Wi‐Fi scenario where the inter‐site interference becomes more serious and the spectral resources are more insufficient. Furthermore, in the next generation of Wi‐Fi standard IEEE 802.11be, the hybrid automatic repeat request (HARQ) and multi‐band technologies will be introduced to solve the problems of unstable delay, serious interference and insufficient spectrum resources. In this paper, retransmission schemes combined multi‐band and hybrid automatic repeat request are deeply studied to improve the retransmission efficiency. Combining hybrid automatic repeat request with multi‐band, this paper proposes three kinds of retransmission mode: insisting on the current frequency band (ICFB) retransmission, switching to the backup frequency band (SBFB) retransmission and concurrent retransmitting on dual‐band (CRDB). Then, an intelligent selection algorithm of retransmission mode based on machine learning is designed to determine the optimal mode. Theoretical analysis and experimental results show that the proposed method can greatly improve the retransmission efficiency and thereby reduce the transmission latency and increase the throughput for multi‐band Wi‐Fi networks.
Eccentricity fault detection in brushless doubly fed induction machines
Authors: Afshar Mojtaba , Abdi Salman , Oraee Ashknaz , Ebrahimi Mohammad , McMahon Richard 
Published: March 2021

AbstractA new fault diagnosis method for detecting the rotor eccentricity faults including static, dynamic and mixed eccentricity is proposed for brushless doubly‐fed induction machines (BDFIMs). BDFIMs are attractive alternatives for the conventional doubly‐fed induction generator (DFIG) for offshore wind power generation; therefore, paying attention to their fault detection is essential. Existing fault detection methods for conventional induction machines cannot be directly applied to the BDFIM due to its special rotor structure and stator winding configurations as well as complex magnetic field patterns. This article proposes a novel fault detection method based on motor current signal analysis to determine stator current harmonics, induced by the nested‐loop rotor slot harmonics (NRSHs), as fault indices. The analysis is performed under healthy conditions and with different types of rotor eccentricity. Finally, a sensitivity analysis is carried out to confirm the practicability of the proposed technique with various fault intensities and load conditions. Analytical winding function approach, finite element analysis and experimental tests on a prototype D180 BDFIM are used in this study to validate the proposed fault detection technique.
A hybrid method for recloser and sectionalizer placement in distribution networks considering protection coordination, fault type and equipment malfunction
Authors: Safari Majid , Haghifam Mahmoud‐Reza , Zangiabadi Mansoureh 
Published: March 2021

AbstractAn effective way to improve distribution system reliability is to place switches and protective equipment in the optimal location. Commonly, in the placement problem, the use of equipment in the designated location is assumed to be possible. But in practice, to establish protection coordination between the equipment, it is necessary to remove or relocate some of the equipment. This paper aims to increase distribution companies' profits and reduce customer interruption costs through a feasible solution. A new hybrid method for equipment placement has been proposed that simultaneously solves the protection coordination problem. While determining the optimal number and location of reclosers and sectionalizers, the proposed method ensures protection coordination between equipment (new and existing devices). Furthermore, to achieve a more realistic and accurate model, factors such as equipment malfunction, fault types (transient and permanent), and the relationship between these faults have been carefully considered to formulate the proposed method. In this method, to solve the optimization problems related to equipment placement and protection coordination, genetic algorithm, and linear programming in MATLAB software have been used, respectively. A real‐life distribution network has been utilized to evaluate the proposed method, and the results show the capability and robustness of this method.
CSNet: Cascade stereo matching network using multi‐information cost volume
Authors: Shao XiaoTao , Zhang Wen , Guo MingKun , Guo SiQi , Qian ManYi 
Published: March 2021

AbstractThe disparity map produced by matching a pair of rectified stereo images provides estimated depth information and accurate distance calculations for autonomous driving. For most stereo matching networks, cost volume plays a crucial role in the accuracy of disparity maps. To increase the accuracy of disparity maps, an improved cost volume method called multi‐information cost volume (MICV) is proposed, with the fusion of concatenation volume and improved correlation volume, which is calculated both in inner product space and Euclidean space, to measure the correlation similarity between features in the left and right images. The inclusion of a squeeze and excitation (SE) module further improves MICV by adjusting the contribution of the correlation volume. To refine the disparity map and enhance the semantics of small objects, a cascade stereo network called CSNet is proposed, with a dilation feature fusion unit (DFFU) to calculate and integrate disparity maps from three different scale branches. The smaller scale branches are gradually integrated into the larger scale branches to implement the transmission of semantic information. The proposed method was evaluated using several established benchmarks including the Sceneow, KITTI2012 and KITTI2015 datasets. Experimental results demonstrate that authors' method produces more accurate disparity maps compared with existing state‐of‐the‐art methods.
Tuneable resonance frequency vibrational energy harvester with electret‐embedded variable capacitor
Authors: Ma Xingchen , Yang Xiaoya , von Seggern Heinz , Dai Ying , He Pengfei , Sessler Gerhard M. , Zhang Xiaoqing 
Published: March 2021

AbstractAn electret‐based electrostatic energy harvester featuring tuneable resonance frequency, small size, light weight, and high output power was designed and its performance predicted by the finite element method and verified by experiment. The device consists of a resilient fluorinated polyethylene propylene (FEP) electret film that is metallised on one side with a small seismic mass attached to its centre and an arc‐shaped counter electrode. In principle, such an energy harvester is mechanically a mass‐spring system and electrically a self‐bias voltage variable capacitor and converts vibrational energy into electrical energy by electromechanical coupling. For an energy harvester sample with dimensions of 30 × 10 × 9 mm for which the last dimension denotes the initial depth of the centre of the harvester, the resonance frequency can be tuned from 17 to 70 Hz by stretching the length of the FEP film loaded with a given seismic mass of 0.06 g. For a seismic mass of 0.1 g, the harvester generated a power up to 797 μW to a matching resistor at its resonance frequency of 17 Hz at an acceleration of 1×g, where g is the gravity of the earth. Such energy harvesters are promising candidates for use in self‐powered electronic devices and wireless sensor network nodes.
Lightweight models for detection of denial‐of‐service attack in wireless sensor networks
Authors: Abidoye Ademola P. , Kabaso Boniface 
Published: March 2021

AbstractWireless sensor networks (WSNs) are becoming more popular in recent times due to the availability of low cost, the short transmission range of sensor nodes and their easy deployment in different application areas; however, security is crucial for WSNs due to the nature of data they transmit in most cases in their locations. Sensor nodes transmit through an open medium and due to the short communication range of each sensor node, a node may need to transmit through many hops to a final destination. Denial‐of‐service (DoS) is one of the attacks that can be launched against WSNs to prevent legitimate nodes from transmitting/receiving data packets. Developing an attack detection and countermeasure system to mitigate the effect of DoS is not an easy task. This work proposes lightweight models for DoS attack detection in WSNs. We developed different lightweight models and algorithms for the detection and elimination of DoS in WSNs and experimented the same. The performance of data delivery ratio, delay, detection rate, energy consumption, and false‐positive was carried out. The experimental results show that the proposed scheme achieved a high true‐positive detection rate, low false‐positive detection rate, energy‐efficient, and high data reliability. Numerical examples are presented to further validate the effectiveness of the proposed scheme.
Update Mammakarzinom 2020 Teil 4 – fortgeschrittenes Mammakarzinom
Authors: Tesch Hans , Müller Volkmar , Wöckel Achim , Ettl Johannes , Belleville Erik , Schütz Florian , Hartkopf Andreas , Thill Marc , Huober Jens , Fasching Peter A. , Kolberg Hans-Christian , Schulmeyer Carla E. , Welslau Manfred , Overkamp Friedrich , Fehm Tanja N. , Lux Michael P. , Schneeweiss Andreas , Lüftner Diana , Janni Wolfgang 
Published: March 2021

ZusammenfassungNachdem in den letzten Jahren bei der Behandlung von Patientinnen mit fortgeschrittenem Mammakarzinom zunehmend Substanzen mit einer guten Effektivität zum Einsatz kommen, die spezifische Signalwege angreifen, sind nun neue Therapien und Ansätze hinzugekommen, die sich tatsächlich auf ganz spezifische Veränderungen beziehen wie die Behandlung von Patientinnen mit HR+/HER2−-Tumoren mit einer PIK3CA-Mutation. Ebenso ist die Behandlung von Patientinnen mit einer BRCA1- oder BRCA2-Mutation durch die Einführung der PARP-Inhibitoren verbessert worden. Nun wird zunehmend versucht, Therapieindikationen aufgrund molekularer Muster auszudehnen und weitere Patientinnen zu identifizieren, die von einer Therapie profitieren könnten, und die neu etablierten Therapiemethoden in bestehende Therapiesequenzen einzubinden. Diese Übersichtsarbeit fasst die neuesten Erkenntnisse in diesem Zusammenhang zusammen.
Head Impact Situations in Professional Football (Soccer)
Authors: Beaudouin Florian , Demmerle Daniel , Fuhr Christoph , Tröß Tobias , Meyer Tim 
Published: March 2021

AbstractTo assess head impact incidents (HIIs) and to distinguish diagnosed head injuries from other incidents, a video observation analysis of match HIIs was conducted in the German Bundesliga (2017/18 season). Video recordings of each match were screened to identify the respective events. Head injury data were identified by a prospective injury registry. HII and head injury incidence rates (IR) were calculated with 95% CIs. The total number of HIIs was 1,362 corresponding to an IR of 134.9/1000 match hours (95% CI 127.9–142.2). In 123 HII (IR 12.2, 95% CI 10.2–14.5) the contact was classified as severe. Head contact with the opponent was the most frequent cause (85%). The most frequent mechanism was in 44% (combined) the arm and elbow-to-head, followed by head-to-head and hand-to-head contacts (each 13%). In 58%, the HIIs occurred during header duels. Twenty-nine head injuries were recorded (IR 2.9, 95% CI 2.0–4.1). Concussions/traumatic brain injuries accounted for 48%, head/facial fractures 24%, head/facial contusions 21%, and lacerations/abrasions 7%. The number of HIIs not classified as concussions/more severe trauma was high. Identification of HIIs and head injury severity should be improved during on-field assessment as many head injuries might go unrecognised based on the large number of HIIs.
Microstructure, elastic modulus, and energy storage properties of portion II in the locust semi-lunar process
Authors: Chen Xiaoyong , Hao Zhixiu 
Published: March 2021

A locust stores the energy needed for jumping in its semi-lunar processes (SLPs) at the end of the hind leg femur, and portion II of the SLP plays a key role in the energy storage–release process. In this paper, scanning electron microscopy and transmission electron microscopy tests were conducted on portion II to determine its microstructure. The elastic moduli of different directions of portion II were tested by atomic force microscopy. Test data demonstrate that portion II is a layered structure formed by lamination of composite layers with a thickness of 1.09 ± 0.44 µm and chitin layers with a thickness of 0.10 ± 0.02 µm, and the composite layer is a fiber-reinforced structure. The elastic moduli of the composite layers along the fiber direction and perpendicular to the fiber direction are 11.32 ± 1.09 GPa and 10.36 ± 2.64 GPa, respectively. Furthermore, the influence of the change in the thickness of the composite layer, the volume ratio of the composite layer, and the fiber volume content in the composite layer on the maximum von Mises stress and strain energy of portion II was analyzed using the finite element method. The analysis results show that the strain energy corresponding to the actual parameters of portion II is close to the maximum. Under this premise, the maximum von Mises stress is close to the minimum. This suggests that the actual parameters give portion II almost the largest energy storage and then the longest fatigue life.
Oligomeric assembly regulating mitochondrial HtrA2 function as examined by methyl-TROSY NMR
Authors: Toyama Yuki , Harkness Robert W. , Lee Tim Y. T. , Maynes Jason T. , Kay Lewis E. 
Published: March 2021

Significance
The HtrA2 protease plays a critical role in ensuring proper cellular function and in regulating a variety of different processes, including programmed cell death. Although the three-dimensional structure of a trimeric form of the enzyme has been determined, the mechanism by which this important molecule is regulated remains to be elucidated. Our data reveal that this is accomplished through a second conformation of the enzyme in which it forms a hexamer with much lower affinity for substrate and by the fact that the enzyme remains in a low-activity state until substrate binding leads to domain reorientations, exposing the catalytic center. Together, these two regulatory features help to minimize proteolysis of nonsubstrate proteins that are required for cellular health.
Projective and amplified symmetries in metric–affine theories
Authors: García-Parrado Alfonso , Minguzzi Ettore 
Published: March 2021

Abstract
In this paper we extend the projective symmetry of the full metric–affine Einstein–Hilbert theory to a new symmetry transformation in the space of affine connections called the amplified symmetry. We prove that the Lagrangian of the standard model of particle physics is invariant under this new symmetry. We also show that the gravitational Lagrangian can be modified so that the amplified symmetry extends to the gravitational sector and hence to the whole action. The new theory so constructed is shown to be dynamically equivalent to Einstein–Cartan’s though genuinely metric–affine.
Black holes in the quadratic-order extended vector–tensor theories
Authors: Minamitsuji Masato 
Published: March 2021

Abstract
We investigate the static and spherically black hole solutions in the quadratic-order extended vector–tensor theories without suffering from the Ostrogradsky instabilities, which include the quartic-order (beyond-)generalized Proca theories as the subclass. We start from the most general action of the vector–tensor theories constructed with up to the quadratic-order terms of the first-order covariant derivatives of the vector field, and derive the Euler–Lagrange equations for the metric and vector field variables in the static and spherically symmetric backgrounds. We then substitute the spacetime metric functions of the Schwarzschild, Schwarzschild–de Sitter/anti-de Sitter, Reissner–Nordström-type, and Reissner–Nordström–de Sitter/anti-de Sitter-type solutions and the vector field with the constant spacetime norm into the Euler–Lagrange equations, and obtain the conditions for the existence of these black hole solutions. These solutions are classified into the two cases 1) the solutions with the vanishing vector field strength; the stealth Schwarzschild and the Schwarzschild–de Sitter/anti-de Sitter solutions, and 2) those with the nonvanishing vector field strength; the charged stealth Schwarzschild and the charged Schwarzschild–de Sitter/anti-de Sitter solutions, in the case that the tuning relation among the coupling functions is satisfied. In the latter case, if this tuning relation is violated, the solution becomes the Reissner–Nordström-type solution. We show that the conditions for the existence of these solutions are compatible with the degeneracy conditions for the class-A theories, and recover the black hole solutions in the generalized Proca theories as the particular cases.
Deriving and validating an electrodynamic model of a voltage transformer from scratch
Authors: El Hage Fabio S , Vieira Fabio P B , Carareto Rodrigo 
Published: March 2021

Abstract
Comprehending the in-depth functioning of a voltage transformer beyond the trivial voltage ratio, generally deducted from the application of Faraday’s law to an open secondary circuit, can be quite challenging for both students and teachers. In this paper, the authors propose an approach that uses Faraday’s and Ohm’s laws alone to derive an electric equivalent circuit for a transformer, with which is possible to accurately explain and predict currents and voltages in its primary and secondary coils under different load resistors connected to the secondary. The authors intend to use a common real-world application as motivation for students to learn Faraday’s law in the context of a modelling and simulation framework, which consists of deriving a model from fundamental physical laws that, after experimental validation, is capable of accurately predicting and explaining a complex phenomenon.
Impact of stoichiometry and strain on Ge1−x
Sn
x
alloys from first principles calculations
Authors: O’Donnell Conor , Sanchez-Soares Alfonso , Broderick Christopher A , Greer James C 
Published: March 2021

Abstract
We calculate the electronic structure of germanium-tin (Ge1−x
Sn
x
) binary alloys for

0
⩽
x
⩽
1

using density functional theory (DFT). Relaxed alloys with semiconducting or semimetallic behaviour as a function of Sn composition x are identified, and the impact of epitaxial strain is investigated by constraining supercell lattice constants perpendicular to the [001] growth direction to the lattice constants of Ge, zinc telluride, or cadmium telluride substrates. It is found that application of 1% tensile strain reduces the Sn composition required to bring the (positive) direct band gap to zero by approximately 5% compared to a relaxed Ge1−x
Sn
x
alloy having the same gap at Γ. On the other hand, compressive strain has comparatively less impact on the alloy band gap at Γ. Using DFT calculated alloy lattice and elastic constants, the critical thickness for Ge1−x
Sn
x
thin films as a function of x and substrate lattice constant is estimated, and validated against supercell DFT calculations and experiment. The analysis correctly predicts the Sn composition range at which it becomes energetically favourable for Ge1−x
Sn
x
/Ge to become amorphous. The influence of stoichiometry and strain is examined in relation to reducing the magnitude of the inverted (‘negative’)

Γ

7

−

–

Γ

8

+

band gap, which is characteristic of semimetallic alloy electronic structure. Based on our findings, strategies for engineering the semimetal-to-semiconductor transition via strain and quantum confinement in Ge1−x
Sn
x
nanostructures are proposed.
Acoustic wave surfing: spin waves and spin pumping driven by elastic wave
Authors: Froes D , Arana M , Sampaio L C , Sinnecker J P 
Published: March 2021

Abstract
In magnon spintronics it is fundamental that magnons can propagate over large distances to allow spin flux or information to be processed. Through micromagnetic simulations we investigate the spin-wave propagation driven by acoustic excitation in narrow Ni stripes, varying the level of coupling between spin and acoustic waves. We consider different cases depending on the extension of the acoustic wave propagation, which is generated on the left end of the stripe. When acoustic waves are confined at the origin, the spin waves are free to propagate but vanish after the decay length, which is dependent on the dissipation. On the other hand, when the acoustic waves are present in the whole stripe, spin and acoustic waves propagate together with the spin wave maintaining a constant amplitude. Images of the spin-wave propagation modes and the dispersion relations are discussed for different acoustic wave attenuation lengths. Motivated by recent experiments, we consider a Pt line over and crossing the Ni stripe and calculate the spin and charge current maps at the Ni/Pt interface and the Pt line, respectively, and the AC and DC components of the inverse spin Hall effect voltage.
Realizing stable half-metallicity in zigzag silicene nanoribbons with edge dihydrogenation and chemical doping
Authors: Song Lingling , Yang Zhihong , Liu Lu , Yuan Liwei , Zhao Han , Chen Xing , Zhang Yan , Zheng Xiaohong 
Published: March 2021

Abstract
Although many schemes have been proposed to obtain full half-metallicity in zigzag silicene nanoribbons with edge monohydrogenation (H–H ZSiNRs) by chemical modification, the resulted negligible energy difference between the antiferromagnetic (AFM) and ferromagnetic (FM) configurations makes the half-metallicity hardly observable practically. In this work, based on density functional calculations, we find that the ZSiNRs with edge dihydrogenation (H2–H2 ZSiNRs) can be tuned to be half-metallic by replacing the central two zigzag Si chains with two zigzag Al–P chains, and more importantly, the FM–AFM energy difference is significantly increased compared with the H–H cases. The obtained half-metallicity originates from the different potential between two edges of the ribbon after doping, which results in the edge states of two spin channels shifting oppositely in energy. This mechanism is so robust that the half-metallicity can always be achieved, irrespective of the ribbon width. Our finding provides a fantastic way for achieving stable half-metallicity in ZSiNRs.