bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi‐task framework of precipitation nowcasting
Authors: Zhang Zheng , Luo Chuyao , Zhang Baoquan , Jiang Hao , Zhang Bowen 
Published: January 2023

AbstractPrecipitation forecasting plays an important role in disaster warning, agricultural production, and other fields. To solve this issue, some deep learning methods are proposed to forecast future radar echo images and convert them into rainfall distributions. Prevailing spatiotemporal sequence prediction methods are usually based on a ConvRNN structure that combines a Convolutional Neural Network and Recurrent Neural Network. However, these existing methods ignore the image change prediction, which causes the coherence of the predicted image has deteriorated. Moreover, these approaches mainly focus on complicating model structure to exploit more historical spatiotemporal representations. Nevertheless, they ignore introducing other valuable information to improve predictions. To tackle these two issues, we propose GCMT‐ConvRNN, a multi‐ask framework of ConvRNN. Except for precipitation nowcasting as the main task, it combines the motion field estimation and sub‐regression as auxiliary tasks. In this framework, the motion field estimation task can provide motion information, and the sub‐regression task offers future information. Besides, to reduce the negative transfer between the auxiliary tasks and the main task, we propose a new loss function based on the correlation of gradients in different tasks. The experiments show that all models applied in our framework achieve stable and effective improvement.
Design of Low‐profile ultrawideband Antennas for Body‐Centric Communications using the FDTD method
Authors: Mokraoui Amine , Khodja Merouane 
Published: January 2023

AbstractLow‐profile coplanar waveguide antennas are successfully designed considering body‐centric communications requirements. A finite difference in time‐domain‐based programme, which considers dispersion in human tissues and antenna dielectric substrates, is developed for this purpose. Parametric simulations and visualisation helped to acquire a greater understanding of radiation mechanisms. Consequently, two approaches are investigated. In the first approach, the antenna bandwidth is optimised regardless of its size and travelling wave antennas with characteristics suitable for on‐body communications are obtained. In the second approach, restricting the bandwidth to ultrawideband (UWB) frequencies, while minimising the antenna size, leads to low‐profile antennas useful for on‐body as well as for off‐body applications. For each approach, several prototypes are built to validate the proposed designs and check the repeatability of the results. Measured and simulated return loss and radiation patterns are coherent. Based on the consulted bibliography, the smallest low‐cost and low‐profile omnidirectional wearable antenna is made, which covers the entire UWB frequencies with no special coaxial connectors or expensive dielectric substrates.
A multi‐objective optimisation for compact wideband and efficient superdirective antenna arrays design using network characteristic modes
Authors: Touhami Abdellah , Collardey Sylvain , Sharaiha Ala 
Published: January 2023

AbstractThis paper introduces a procedure for multi‐objective optimisation, for compact wideband superdirective antenna array design, using network characteristic modes. The two main objectives considered are the maximisation of the directivity in the end‐fire direction, simultaneously with the minimisation of the input reflection coefficient in a large bandwidth. The proposed method is used thereafter for designing a three‐element superdirective small Yagi antenna, with an overall dimensions of 0.4λ × 0.37λ × 0.18λ. The length of this mini yagi antenna is 60% shorter than a classical one, with the same performances of gain and bandwidth. The measured results show that the antenna bandwidth, maximum gain, and efficiency are of 11.2%, 8 dBi, and 95% respectively.
Grid interaction of multi‐VSC systems for renewable energy integration
Authors: Ahmadloo Fatemeh , Pirooz Azad Sahar 
Published: January 2023

AbstractIntegration of converter‐interfaced renewable energy sources (RESs) into the power system and the transfer of power from RESs to remote load centres over high‐voltage direct current (HVDC) lines may require connecting multiple voltage‐sourced converters (VSCs) to a common alternating current (AC) system. Because of this connection, control loops of various converters will interact through the AC grid, leading to instability and an undesirable transient response. This paper focuses on the system‐level integration of multi‐VSC systems for the integration of RESs. μ analysis is used to determine under which control modes the independently stabilized VSCs connected to a common AC system ensure the multi‐VSC system stability. Furthermore, a sufficient criterion is proposed for the design of the converters' outer control loops independently to ensure the stability of the interconnected multi‐VSC system. For cases of severe interactions, where the interconnected multi‐VSC system may become unstable even if individual VSCs are stable, a joint controller design for converters is proposed to stabilize the multi‐VSC system. The interaction analysis indicates that employing AC voltage control mode by all the converters causes the highest interaction level, and having more converters in reactive power control mode reduces the impact of interactions on the interconnected system stability.
Improving the flexibility of power systems using transportable battery, transmission switching, demand response, and flexible ramping product market in the presence of high wind power
Authors: Shoferpour Alireza , Karimi Ali 
Published: January 2023

AbstractWith the increasing demand for electricity and the significant growth of renewable energy sources (RES), especially wind power, the need for new services to increase system flexibility has increased more than ever. Flexibility services can enhance system security. This paper proposes a framework for enhancing system flexibility by integrating emerging services for running the day‐ahead energy, spinning, and flexible ramping product (FRP) markets, considering high wind power penetration. Due to the uncertainty of wind power production, this framework is presented as a stochastic network‐constraint unit commitment (NCUC) problem. The services that are implemented simultaneously in the problem include transmission switching (TS), demand response (DR) program, and transportable battery energy storage (TBES). Moreover, two new indices are introduced to evaluate the effects of flexibility services. Another contribution of this paper is performing comprehensive studies for comparing various case studies in normal and the worst contingency conditions of the network. The IEEE RTS‐79 test system is employed to approve the effectiveness of the proposed framework. The results of various case studies show that using emerging services together increases power grid flexibility and reduces system operating costs.
Rossby waves on stellar equatorial β planes: Uniformly rotating radiative stars
Authors: Albekioni M. , Zaqarashvili T. V. , Kukhianidze V. 
Published: January 2023

Context. Rossby waves arise due to the conservation of total vorticity in rotating fluids and may govern the large-scale dynamics of stellar interiors. Recent space missions have collected a lot of information about the light curves and activity of many stars, which triggered observations of Rossby waves in the stellar surface and interiors.
Aims. We aim to study the theoretical properties of Rossby waves in stratified interiors of uniformly rotating radiative stars with a sub-adiabatic vertical temperature gradient.
Methods. We used the equatorial β plane approximation and linear vertical gradient of temperature to study the linear dynamics of equatorially trapped Rossby and inertia-gravity waves in interiors of radiative stars. The governing equation was solved by the method of separation of variables in the vertical and latitudinal directions.
Results. Vertical and latitudinal solutions of the waves are found to be governed by Bessel functions and Hermite polynomials, respectively. Appropriate boundary conditions at the stellar surface and poles define analytical dispersion relations for Rossby, Rossby-gravity, and inertia-gravity waves. The waves are confined in surface layers of 30–50 H0, where H0 is the surface density scale height, and they are trapped between the latitudes of ±600. Observable frequencies (normalised by the angular frequency of the stellar rotation) of Rossby waves with m = 1 (m = 2), where m is the toroidal wavenumber, are in the interval of 0.65–1 (1.4–2), depending on the stellar rotation, radius, and surface temperature.
Conclusions. Rossby-type waves can be systematically observed using light curves of Kepler and TESS (Transiting Exoplanet Survey Satellite) stars. Observations and theory then can be used for the sounding of stellar interiors.
Probing the spacetime and accretion model for the Galactic Center: Comparison of Kerr and dilaton black hole shadows
Authors: Röder Jan , Cruz-Osorio Alejandro , Fromm Christian M. , Mizuno Yosuke , Younsi Ziri , Rezzolla Luciano 
Published: January 2023

Context. In the 2017 observation campaign, the Event Horizon Telescope (EHT) for the first time gathered enough data to image the shadow of the supermassive black hole (SMBH) in M 87. Most recently in 2022, the EHT has published the results for the SMBH at the Galactic Center, Sgr A*. In the vicinity of black holes, the influence of strong gravity, plasma physics, and emission processes govern the behavior of the system. Since observations such as those carried out by the EHT are not yet able to unambiguously constrain models for astrophysical and gravitational properties, it is imperative to explore the accretion models, particle distribution function, and description of the spacetime geometry. Our current understanding of these properties is often based on the assumption that the spacetime is well described by the Kerr solution to general relativity, combined with basic emission and accretion models. We explore alternative models for each property performing general relativistic magnetohydrodynamic (GRMHD) and general relativistic radiative transfer (GRRT) simulations.
Aims. By choosing a Kerr solution to general relativity and a dilaton solution to Einstein-Maxwell-dilaton-axion gravity as exemplary black hole background spacetimes, we aim to investigate the influence of accretion and emission models on the ability to distinguish black holes in two theories of gravity.
Methods. We carried out 3D GRMHD simulations of both black holes, matched at their innermost stable circular orbit, in two distinct accretion scenarios: standard and normal evolution (SANE) and a magnetically arrested disk (MAD). Using GRRT calculations, we modeled the thermal synchrotron emission and subsequently applied a nonthermal electron distribution function, exploring representative parameters to compare with multiwavelength observations. We further considered Kerr and dilaton black holes matched at their unstable circular photon orbits, as well as their event horizons.
Results. From the comparison of GRMHD simulations, we find a wider jet opening angle and higher magnetization in the Kerr spacetime. Generally, MAD models show larger magnetic flux than SANE, as is expected. The GRRT image morphology shows differences between spacetimes due to the Doppler boosting in the Kerr spacetime. However, from pixel-by-pixel comparison, we find that in a real-world observation an imaging approach may not be sufficient to distinguish the spacetimes using the current finite resolution of the EHT. From multiwavelength emission and spectral index analysis, we find that the accretion model and spacetime have only a small impact on the spectra compared to the choice of the emission model. Matching the black holes at the unstable photon orbit or the event horizon further decreases the observed differences.
Detailed composition of iron ions in interplanetary coronal mass ejections based on a multipopulation approach
Authors: Gu Chaoran , Heidrich-Meisner Verena , Wimmer-Schweingruber Robert F. , Yao Shuo 
Published: January 2023

Context. Coronal mass ejections (CMEs) are extremely dynamical, large-scale events in which plasma – but not only the coronal plasma – is ejected into interplanetary space. If a CME is detected in situ by a spacecraft located in the interplanetary medium, it is then called an interplanetary coronal mass ejection (ICME). This solar activity has been studied widely since coronagraphs were first flown into space in the early 1970s.
Aims. Charge states of heavy ions reflect important information about the coronal temperature profile due to the freeze-in effect and it is estimated that iron ions freeze in at heights of ∼5 solar radii. However, the measured charge-state distribution of iron ions cannot be composed of only one single group of plasma. To identify the different populations of iron charge-state composition of ICMEs and determine their sources, we developed a model that independently uses two, three, and four populations of iron ions to fit the measured charge-state distribution in ICMEs detected by the Advanced Composition Explorer (ACE) at 1 AU.
Methods. Three parameters are used to identify a certain population, namely freeze-in temperature, relative abundance, and kappa value (κ), which together describe the potential non-Maxwellian kappa distributions of coronal electrons. Our method chooses the reduced chi-squared to describe the goodness of fit of the model to the observations. The parameters of our model are optimized with the covariance-matrix-adaptation evolution strategy (CMA-ES).
Results. Two major types of ICMEs are identified according to the existence of hot material, and both, that is, the cool type and the hot type, have two main subtypes. Different populations in those types have their own features related to freeze-in temperature and κ. The electron velocity distribution function usually contains a significant hot tail in typical coronal material and hot material, while the Maxwellian distribution appears more frequently in mid-temperature material. Our model is also suitable for all types of solar wind and the existence of hot populations as well as the change of temperatures of individual populations may indicate boundaries between ICMEs and individual solar wind streams.
Telemedizinische Unterstützung der feto-neonatalen Versorgung
in einer Region – Teil I: Bedarfsanalyse am Beispiel
Ost-Sachsen
Authors: Kaufmann Maxi , Eckart Falk , Rüdiger Mario , Birdir Cahit , Mense Lars 
Published: January 2023

ZusammenfassungEine optimale feto-neonatale Versorgung schafft die Grundlage für ein
gesundes Aufwachsen und erfordert die Zusammenarbeit verschiedener Akteure des
Gesundheitswesens. Bundesweite demographische Veränderungen mit einem
zunehmenden Rückzug der Bevölkerung aus dem ländlichen
Raum erfordern auch in Ostsachsen eine Anpassung der Strukturen, um eine
wohnortnahe, höchsten Qualitätsansprüchen
genügende Versorgung sicher zu stellen. Für die Region
Ostsachsen wurden mehrere Bereiche identifiziert, in denen ein besonderer Bedarf
an regionaler, perinataler Zusammenarbeit besteht: (I) multiprofessionelle
Beratung bei Hinweisen auf fetale Erkrankungen, (II) sofortige neonatologische
Expertise bei einer Neugeborenen-Reanimation, (III) evidenzbasierte neonatale
Antibiotikatherapie, (IV) heimatnahe Entlassung extrem unreifer
Frühgeborener und kranker Neugeborener, (V) adäquate
psychosoziale Unterstützung von Familien Früh- und kranker
Neugeborener. Telemedizin ermöglicht eine rasche, zeiteffiziente
Kommunikation zwischen Partnern und einen audiovisuellen Eindruck des Patienten.
In der Zusammenarbeit des Zentrums für Feto/Neonatale Gesundheit
mit den regionalen Partnern wird in Ostsachsen mit der Hilfe telemedizinischer
Verfahren ein Versorgungsnetz „Sichere Geburt“ aufgebaut, und
als Projekt des Innovationsfonds des G-BA evaluiert, das potentiell für
andere Regionen Modellcharakter haben kann.
Risk of total metachronous advanced neoplasia at surveillance colonoscopy after detection of serrated lesions: a matched case–cohort study
Authors: Djinbachian Roupen , Lafontaine Marie-Lyssa , Anderson Joseph C. , Pohl Heiko , Dufault Talia , Boivin Michel , Bouin Mickael , von Renteln Daniel 
Published: January 2023

Background Serrated lesions are potential colorectal cancer precursors. This study evaluated the presence of total metachronous advanced neoplasia (T-MAN) at follow-up in patients with index serrated lesions compared with a matched cohort without serrated lesions.
Methods Patients aged 45–74 years with serrated lesions were matched 2:1 by sex, age, synchronous polyps, and timing of index colonoscopy, to patients without serrated lesions. The primary outcome was T-MAN (advanced adenoma or high-risk serrated lesion) at follow-up. Secondary outcomes included presence of T-MAN stratified by synchronous polyps and serrated lesion characteristics.
Results 1425 patients were included (475 patients, 642 serrated lesions; 950 controls; median follow-up 2.9 versus 3.6 years). Patients with serrated lesions had greater risk of T-MAN than those without (hazard ratio [HR] 6.1, 95 %CI 3.9–9.6). Patients with serrated lesions and high-risk adenoma (HRA) had higher risk of T-MAN than those with HRA alone (HR 2.6, 95 %CI 1.4–4.7); similarly, patients with serrated lesions plus low-risk adenoma (LRA) had higher risk than those with LRA alone (HR 7.0, 95 %CI 2.8–18.4), as did patients with serrated lesions without adenoma compared with no adenoma (HR 14.9, 95 %CI 6.5–34.0). Presence of proximal sessile serrated lesion (SSL; HR 9.3, 95 %CI 5.4–15.9), large SSL (HR 17.8, 95 %CI 7.4–43.3), and proximal large SSL (HR 25.0, 95 %CI 8.8–71.3), but not distal SSL, were associated with greater risk for T-MAN.
Conclusion Patients with serrated lesions had higher risk for T-MAN regardless of synchronous adenomas. Patients with serrated lesions and HRA, and those with large or proximal SSLs, were at greatest risk.
Strategies of clausal postmodification in learner English
Authors: Vuuren Sanne van , Berns Janine , Bank Marketa 
Published: January 2023

AbstractThe difficulty of automatically extracting syntactic structures from authentic learner data has previously limited the kinds of questions addressed by meansof Contrastive Interlanguage Analysis(CIA;Granger, 2015), or has forced researchers to resort to manual analysis of smaller corpora. This study responds to the call for greater use of parsed corpora by using automated parsing and refined corpus analysis software to investigate advanced EFL learners’ use of relative and participial clauses for nominal postmodification. The use of clausal postmodifiers inside the noun phrase may be seen as a marker of proficiency and syntactic maturity in academic writing, but the proportional use of relative and participial clauses for nominal postmodification may also be subject to L1 transfer. To investigate the role of transfer and syntactic maturity in the use of nominal postmodification, we compare texts written by Dutch EFL learners with those produced by learners from typologically distinct L1s, i.e. Czech and French, and by native speakers of English. Use of participial clauses and relative clauses in Dutch learners’ EFL texts is then compared with their use in L1 Dutch. The high degree of L1-interlanguage congruity suggests that transfer plays an important role in the Dutch learners’ strong preference for relative clauses for nominal postmodification. Based on the comparison with both other learner groups, we hypothesize that such transfer effects in the use of clausal postmodification can only emerge once the learner has reached a sufficient level of syntactic maturity in the target language.
Key comparison COOMET.QM-K120 "Carbon dioxide in air at urban level (480–800) μmol/mol"
Authors: Konopelko L , Kolobova A , Chubchenko I , Efremova O , Rozhnov M , Melnyk D , Kisel S , Levbarg O , Shpilnyi S , Yakubov S , Mironchik A , Aleksandrov V , Kai F M , Wu T Y , Fang J , Cui Y , Mou J , Liu W 
Published: January 2023

Main text
This article presents the report on the COOMET key comparison COOMET.QM-K120, which is designed as linking to the appropriate CCQM comparison - CCQM-K120.b "Carbon dioxide in air at urban level (480–800) μmol/mol" carried out in 2016-2018.
CCQM-K120.b is considered as a Track A comparison and tests core skills and competencies required in gravimetric preparation, analytical certification and purity analysis. Participants successful in CCQM-K120.b and the linked COOMET.QM-K120 comparison may use their results in the flexible scheme and underpin claims for all core mixtures in accordance with the GAWG strategy document.
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Numerical investigation of localization in two-dimensional quasiperiodic mosaic lattice
Authors: Wang Hui-Hui , Wang Si-Si , Yu Yan , Zhang Biao , Dai Yi-Ming , Chen Hao-Can , Zhang Yi-Cai , Zhang Yan-Yang 
Published: January 2023

Abstract
A one-dimensional lattice model with mosaic quasiperiodic potential is found to exhibit interesting localization properties, e.g. clear mobility edges (Wang et al 2020 Phys. Rev. Lett.
125 196604). We generalize this mosaic quasiperiodic model to a two-dimensional version, and numerically investigate its localization properties: the phase diagram from the fractal dimension of the wavefunction, the statistical and scaling properties of the conductance. Compared with disordered systems, our model shares many common features but also exhibits some different characteristics in the same dimensionality and the same universality class. For example, the sharp peak at

g
∼
0

of the critical distribution and the large g limit of the universal scaling function β resemble those behaviors of three-dimensional disordered systems.
Magnetic fields produced by ‘seen arc’ and ‘unseen arc’ of ideal solenoids are the same in magnitude but opposite in direction
Authors: Khalifah Ardi , Abdullah Mikrajuddin 
Published: January 2023

Abstract
We divide the solenoid into ‘seen arc portion’ and ‘unseen arc portion’ when observed from the point of measurement. The magnitudes of fields produced by the two portions are the same but in opposite directions. This is the reason why the magnetic field outside an ideal solenoid is zero. Interestingly, the magnitude of the field produced by each portion follows the change of angle of view to the outer boundary of the solenoid when observed from the point of measurement. We have also distributed questionaries to students to get feedback on whether the topics discussed in this paper are easy for undergraduate students to understand.