bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silicon circuits for chip‐to‐chip communications in multi‐socket server board interconnects
Authors: Moralis‐Pegios Miltiadis , Pitris Stelios , Mitsolidou Charoula , Fotiadis Konstantinos , Ramon Hannes , Lambrecht Joris , Bauwelinck Johan , Yin Xin , Ban Yoojin , De Heyn Peter , Van Campenhout Joris , Lamprecht Tobias , Lehnman Andreas , Pleros Nikos , Alexoudi Theoni 
Published: March 2021

AbstractMulti‐socket server boards (MSBs) exploit the interconnection of multiple processor chips towards forming powerful cache coherent systems, with the interconnect technology comprising a key element in boosting processing performance. Here, we present an overview of the current electrical interconnects for MSBs, outlining the main challenges currently faced. We propose the use of silicon photonics (SiPho) towards advancing interconnect throughput, socket connectivity and energy efficiency in MSB layouts, enabling a flat‐topology wavelength division multiplexing (WDM)‐based point‐to‐point (p2p) optical MSB interconnect scheme. We demonstrate WDM SiPho transceivers (TxRxs) co‐assembled with their electronic circuits for up to 50 Gb/s line rate and 400 Gb/s aggregate data transmission and SiPho arrayed waveguide grating routers that can offer collision‐less time of flight connectivity for up to 16 nodes. The capacity can scale to 2.8 Gb/s for an eight‐socket MSB, when line rate scales to 50 Gb/s, yielding up to 69% energy reduction compared with the QuickPath Interconnect and highlighting the feasibility of single‐hop p2p interconnects in MSB systems with >4 sockets.
Co‐packaged datacenter optics: Opportunities and challenges
Authors: Minkenberg Cyriel , Krishnaswamy Rajagopal , Zilkie Aaron , Nelson David 
Published: March 2021

AbstractHigh‐capacity, high‐density, power‐, and cost‐efficient optical links are undoubtedly of critical importance for datacenter infrastructure. However, the optics roadmap has come to a fork in the road: Is it right to continue on the tried and proven path of pluggable modules or is it time to adopt a new deployment model that involves co‐packaged optics? Herein, we aim to shed light on the trade‐offs involved, enabling technologies, paths to adoption, and potential impact on datacenter network architecture.
Transient and steady‐state study of a speed sensorless IPMSM drive with an advanced integrator‐based stator flux estimator
Authors: Sharma Toshi , Bhattacharya Avik , Ahmed Haris 
Published: March 2021

AbstractIn this paper, an advanced integrator is proposed for the estimation of stator flux in a direct torque control (DTC) drive. A two‐level lookup table‐based direct torque‐controlled interior permanent magnet synchronous motor (IPMSM) drive is implemented. DTC has the inherent disadvantage of DC drift and saturation in stator flux estimation due to a pure integrator. In the proposed work, a different approach to estimate stator flux is reported overcoming the constraints of a pure integrator in DTC. An advanced integrator with an adaptive controller is implemented to determine the stator flux and enrich the performance of the drive. A comparison of transient and steady‐state analysis is carried out when IPMSM is fed by a low‐pass filter‐based DTC and proposed stator flux estimator‐based DTC. To make the system mechanically robust, stator current‐based model reference adaptive control is executed to estimate the motor speed. A mathematical derivation for the stability study of the adaptation mechanism is carried out using Popov's hyperstability criteria. The proposed algorithm is implemented in the MATLAB/Simulink environment and the soundness of the proposed work is presented by simulation results. Moreover, the experimental analysis using dSPACE1104 justifies the simulation results of the proposed system.
Arm current reversal‐based modular multilevel DC‐DC converter
Authors: Nazih Yousef , Hossam‐Eldin Ahmed , Elserougi Ahmed 
Published: March 2021

AbstractNowadays, most of the converters used in high‐power high‐voltage (HV) applications are the conventional modular multilevel converters (MMC). However, in the case of DC‐DC conversion, an imbalance of the capacitor voltages occurs and the conventional MMC fails to operate correctly. This paper introduces an arm current reversal‐based modular multilevel DC‐DC converter, which successfully provides balance among the capacitor voltages while operating in DC‐DC conversion. The proposed configuration is used in medium voltage DC grids to feed DC loads or to interconnect between two DC grids of different voltage levels. The proposed converter is a two‐stage DC‐DC modular converter, which consists of a single‐phase half‐bridge MMC with half‐bridge submodules (HBMMC) followed by a single‐phase H‐bridge MMC with half‐bridge submodules (SMs). The operational concept of the proposed converter is based on reversing the arm current direction and reversing the output terminals with the help of the H‐bridge MMC stage, which ensures the same direction of the voltage at the load terminals. The proposed converter provides a high conversion ratio, bidirectional power flow, simple architecture, and a simple control scheme. Detailed illustrations, analysis, and design of the proposed converter are presented. Besides, MATLAB‐based and Opal RT‐based simulation results and experimental results are presented to validate the proposed configuration claims.
A novel active current co‐efficient extraction‐based control for grid‐tied solar photovoltaic system
Authors: Jalan Subham Kumar , Babu B. Chitti , Patel Nirav , Kumar Ajay , Gupta Nitin 
Published: March 2021

AbstractIn this paper, a novel active current co‐efficient extraction (ACCE)‐based control method is presented for a three‐phase grid‐interfaced voltage source inverter (VSI). Since the VSI performance largely depends on the reference current generation method, it is of significance to identify the active current co‐efficient of the load current contaminated with harmonics, as it is a key governing factor that decides the shape of the compensating current. The proposed ACCE structure functions with minimal mathematical operators like product, sum, and integrators and thereby identifies the fundamental current with computational effectiveness. Besides, in comparison to existing prevalent state‐of‐the‐art methods, the proposed ACCE structure is devoid of any low‐pass filter and zero‐crossing detector, and hence serves the following two distinctive purposes: (i) Ensures minimum steady‐state oscillations and (ii) exhibits improved dynamic performance under disturbances in the grid and load. The proposed structure effectively confronts the various power quality challenges while injecting the active power into the utility grid. Further, the incremental‐conductance‐based maximum power point tracking algorithm is equipped to extract the maximum possible power from the photovoltaic array. Finally, the effectiveness of the proposed ACCE structure has been investigated through MATLAB/Simulink software studies followed by dSPACE‐1104‐based experimental setup.
Generalized diamond‐type single DC‐source switched‐capacitor based multilevel inverter with step‐up and natural voltage balancing capabilities
Authors: Deliri Saeid , Varesi Kazem , Siwakoti Yam P. , Blaabjerg Frede 
Published: March 2021

AbstractThis paper proposes a diamond‐shaped high step‐up switched‐capacitor based basic multilevel inverter topology. The basic switched‐capacitor (SC) stage consists of 2 active switches, 2 diodes, and 2 capacitors. Using a single DC source with the unfolding circuit (10 switches, 5 capacitors, and 5 diodes) results in the production of 17 voltage‐steps at the output with the gain of up to 8 times of the input voltage. By extending the diamond‐shaped switched‐capacitor stages, higher voltage levels and voltage gains can be possible. The suggested topology employs two half‐bridges (instead of a full‐bridge) to produce positive, zero, and negative steps, which reduces the Voltage Stress (VS) on two output switches and consequently reduces Total Voltage Stress (TVS). In addition, the natural voltage balancing of capacitors eliminates the need to an additional control circuitry and consequently reduces the total converter size, complexity, and cost. In addition, modularity, scalability, low voltage ripple on capacitors, low total voltage stress, high power quality, and capability of supplying low/medium power factor (R‐L) loads are some of the merits of the proposed topology. The low Cost Function (CF) obtained in the comparison section as well as experimental results verifies the advantages of the proposed topology.
Day‐ahead wind power combination forecasting based on corrected numerical weather prediction and entropy method
Authors: Yang Mao , Dai Bozhi , Wang Jinxin , Chen Xinxin , Sun Yong , Li Baoju 
Published: March 2021

AbstractTo satisfy the grid operation scheduling requirements for wind power forecasting model accuracy, the measured wind speed near the height of the wind turbine hub is added to the wind power combined forecasting model. First, the relationship between the numerical weather prediction wind speed and the measured wind speed at different heights are analysed, and the correlation between each wind speed and the wind power is compared. Second, the random forest algorithm combined with the cumulative contribution rate is used to select several meteorological types of numerical weather prediction data as the input of the long short‐term memory network to predict wind speed. Third, while inputting the meteorological data provided by numerical weather prediction, which is highly related to wind power, the wind power prediction network also uses the predicted wind speed of the upper network as input to predict wind power. Finally, the entropy method is used to dynamically determine the combined weights of each forecasting model and improve the adaptability of the model. Research and analysis using measured data from two wind farms located in northeast China have verified the effectiveness of the method.
Fundamental study related to the development of modular solar panel for improved durability and repairability
Authors: Majdi Abdulrhman , Alqahtani Mohammed Dhafer , Almakytah Abdulmalik , Saleem Muhammad 
Published: March 2021

AbstractSolar panels around the globe are primarily designed as a plug‐and‐play solution and the end users are not allowed to repair the panel in case of damage. Natural loadings such wind, snow, sand and hail can lead to irreparable damage to the solar panels and the easiest solution to fix the damaged solar panel is to replace it. This design philosophy leads to a huge quantity of electronic waste as it completely ignores the repairability of the solar panels. In this regard, the presented research work details the development and testing of modular solar panel with performance similar to the traditional design. The modular design was tested for power transfer, re‐connection upon impact and the ability to replace the selected parts in case of permanent damage without the need of replacing the entire solar panel. This experimental research work delivers a modular solar panel design that has ease of repairability in case of damage. Furthermore, a detailed economic analysis has been provided for several real‐world scenarios that indicate its suitability over existing commercially available solutions.
Design and optimisation of a bidirectional flux modulation machine for AC and DC power supplies
Authors: Qifang Lin , Niu Shuangxia , Wu Huihuan , Fu Weinong 
Published: March 2021

AbstractThis study proposes a novel power supply system that utilises wind power to produce AC and DC power. A special designed generator based on bidirectional flux modulation effect is the key part of the proposed power supply system. The novel power system has a compact structure since the proposed generator has two electric port. There are three essential points that make the proposed system outstanding. One is the contra‐rotating rotors, which will cluster wind power even under low wind speed. Second one is the dual armature winding structure, which will provide AC and DC power simultaneously. There are two electric port in the proposed generator. One port can produce AC power to the non‐sensitive resistive load. The other can provide AC power with different frequency to the rectifier to obtain DC power. The induced voltage due to flux modulation effect can be used to offer AC power, and the induced voltage due to the outer rotor can be used to offer DC power. The voltage frequency of two sets windings is different. The last one is the air gap flux rotation speed amplification due to flux modulation effect. Time stepping finite element method is used to analyse the dynamic performance of the proposed machine.
Coordinated control of rotor kinetic energy and pitch angle for large‐scale doubly fed induction generators participating in system primary frequency regulation
Authors: Yang Peihong , He Bin , Wang Biao , Dong Xiaoling , Liu WenYing , Zhang Jihong , Wu ZhenKui , Liu Jing‐Xia , Qin Zhigang 
Published: March 2021

AbstractThis paper presents a control strategy of large‐scale wind‐thermal power joint primary frequency regulation. First, an integrated control strategy is established rotor kinetic energy control and pitch angle control for wind turbine generators participation in frequency regulation within a wide range of wind velocity; Second, a fuzzy PI controller is designed for the recovery control of the wind turbine, which can avoid the occurrence of the frequency secondary drop accident during the wind generator exits the frequency regulation. Third, an optimal allocation power strategy of wind generator frequency modulation based on weighting factors is proposed in different operating conditions to make full use of the frequency modulation capability of wind turbine rotor kinetic energy control, and the strategy of orderly exiting the frequency modulation of the wind generators is established. Finally, the control framework for proposing the strategy is constructed to enhance the primary frequency regulation ability of large‐scale wind generators connected to power systems. The feasibility of proposing the strategy is verified by two examples. The results show that the presented strategy is able to heighten the characteristics of the power system frequency response availably and provide a reference for power system scheduling with large‐scale wind power.
A co‐occurrence matrix‐based matching area selection algorithm for underwater gravity‐aided inertial navigation
Authors: Wang Chenglong , Wang Bo , Deng Zhihong , Fu Mengyin 
Published: March 2021

AbstractThe matching area selection algorithm is one of the key technologies for underwater gravity‐aided inertial navigation system, which directly affects the positioning accuracy and matching rate of underwater navigation. The traditional matching area selection algorithms usually use the statistical characteristic parameters of gravity field. However, the traditional algorithms are difficult to reflect the spatial relation characteristic of gravity field, which always miss some latent matching areas with obvious change of gravity field. In order to solve this problem, the matching area selection algorithm based on co‐occurrence matrix is proposed. The proposed algorithm establishes gravity anomaly co‐occurrence matrix and extracts spatial relation characteristic parameters to reflect the gravity field. The comprehensive spatial characteristic parameter is built by entropy and is used to select the matching area by maximization of inter‐class variance. The experimental results show that the proposed algorithm can select more effective matching areas than the traditional algorithms.
Numerical analysis of the Volterra differential equations via a combination of evolutionary algorithms with moving least squares and finite difference methods
Authors: Mahmoodabadi Mohammad Javad 
Published: March 2021

AbstractIn this paper, the Volterra differential equations governing on the predator‐prey dynamics is numerically solved through the combination of evolutionary algorithms with Moving Least Squares as well as the Finite Difference Method. Among the numerous evolutionary algorithms, the Genetic Algorithms and Particle Swarm Optimization, as two powerful and effective approaches, are selected. The penalty method is chosen to impose the initial conditions on the objective function, while the Moving Least Squares is implemented to interpolate the derivatives in the differential equations. In order to illustrate the effectiveness of the Moving Least Squares, the results are compared with those obtained via the Finite Difference Method based evolutionary algorithms. Moreover, the results are associated with those of a numerical method and an analytical scheme to evaluate the obtained populations of the prey and the predator. These comparisons clearly illustrate the reliability and efficiency of the proposed methodology to solve nonlinear differential equations.
A SOPHIE RV search for giant planets around young nearby stars (YNS)
Authors: Grandjean A. , Lagrange A.-M. , Meunier N. , Rubini P. , Desidera S. , Galland F. , Borgniet S. , Zicher N. , Messina S. , Chauvin G. , Sterzik M. , Pantoja B. 
Published: March 2021

Context.The search of close (a≲ 5 au) giant planet (GP) companions with radial velocity (RV) around young stars and the estimate of their occurrence rates is important to constrain the migration timescales. Furthermore, this search will allow the giant planet occurrence rates to be computed at all separations via the combination with direct imaging techniques. The RV search around young stars is a challenge as they are generally faster rotators than older stars of similar spectral types and they exhibit signatures of magnetic activity (spots) or pulsation in their RV time series. Specific analyses are necessary to characterize, and possibly correct for, this activity.Aims.Our aim is to search for planets around young nearby stars and to estimate the GP occurrence rates for periods up to 1000 days.Methods.We used the SOPHIEspectrograph on the 1.93 m telescope at the Haute-Provence Observatory to observe 63 A−Myoung (<400 Myr) stars. We used our Spectroscopic data via Analysis of the Fourier Interspectrum Radial velocities software to compute the RVs and other spectroscopic observables. We then combined this survey with the HARPSYNS survey to compute the companion occurrence rates on a total of 120 youngA−Mstars.Results.We report one new trend compatible with a planetary companion on HD 109647. We also report HD 105693 and HD 112097 as binaries, and we confirm the binarity of HD 2454, HD 13531, HD 17250 A, HD 28945, HD 39587, HD 131156, HD 142229, HD 186704 A, and HD 195943. We constrained for the first time the orbital parameters of HD 195943 B. We refute the HD 13507 single brown dwarf (BD) companion solution and propose a double BD companion solution. Two GPs were previously reported from this survey in the HD 113337 system. Based on our sample of 120 young stars, we obtain a GP occurrence rate of 1−0.3+2.2% for periods lower than 1000 days, and we obtain an upper limit on BD occurrence rate of 0.9−0.9+2% in the same period range. We report a possible lack of close (P∈ [1;1000] days) GPs around young FK stars compared to their older counterparts, with a confidence level of 90%.
Modeling chemistry during star formation: water deuteration in dynamic star-forming regions
Authors: Jensen S. S. , Jørgensen J. K. , Furuya K. , Haugbølle T. , Aikawa Y. 
Published: March 2021

Context. Recent observations of the HDO/H2O ratio toward protostars in isolated and clustered environments show an apparent dichotomy, where isolated sources show higher D/H ratios than clustered counterparts. Establishing which physical and chemical processes create this differentiation can provide new insights into the chemical evolution of water during star formation and the chemical diversity during the star formation process and in young planetary systems.
Aims. We seek to determine to what degree the local cloud environment influences the D/H ratio of water in the hot corinos toward low-mass protostars and establish which physical and chemical conditions can reproduce the observed HDO/H2O and D2O/HDO ratios in hot corinos.
Methods. The evolution of water during star formation is modeled using 3D physicochemical models of a dynamic star-forming environment. The physical evolution during the protostellar collapse is described by tracer particles from a 3D MHD simulation of a molecular cloud region. Each particle trajectory is post-processed using RADMC-3D to calculate the temperature and radiation field. The chemical evolution is simulated using a three-phase grain-surface chemistry model and the results are compared with interferometric observations of H2O, HDO, and D2O in hot corinos toward low-mass protostars.
Results. The physicochemical model reproduces the observed HDO/H2O and D2O/HDO ratios in hot corinos, but shows no correlation with cloud environment when similar initial conditions are tested. The observed dichotomy in water D/H ratios requires variation in the initial conditions, for example the duration and temperature of the prestellar phase. Reproducing the observed D/H ratios in hot corinos requires a prestellar phase duration t ~ 1−3 Myr and temperatures in the range T ~ 10−20 K prior to collapse. Furthermore, high cosmic-ray ionization rates (ξH2 ~ 10−15 s−1) appear to be incompatible with the observed D/H ratios toward low-mass protostars.
Conclusions. This work demonstrates that the observed differentiation between clustered and isolated protostars stems from differences in the molecular cloud or prestellar core conditions and does not arise during the protostellar collapse itself. The observed D/H ratios for water in hot corinos are consistent with chemical inheritance of water, and no resetting during the protostellar collapse, providing a direct link between the prestellar chemistry and the hot corino.
Auswirkungen geburtshilflicher Analgesie mit systemischen Opioiden auf das Neugeborene – eine Übersichtsarbeit
Authors: Seiler Berenike , Deindl Philipp , Somville Thierry , Ebenebe Chinedu Ulrich , Hecher Kurt , Singer Dominique 
Published: March 2021

Zusammenfassung
Einleitung Dreiviertel aller Gebärenden erhalten während der Geburt eine Analgesie. Es stehen regionale und systemische Analgesieverfahren zur Verfügung. Diese Übersichtsarbeit analysiert die Datenlage zu den Auswirkungen einer geburtshilflichen Analgesie mit systemischen Opioiden auf das Neugeborene.
Methoden Die Datenbanken PubMed und Cochrane Library wurden nach den folgenden Begriffen durchsucht: „Meptazinol“, „Meptid“, „analgesia“, „painkiller“, „pain reliever“, „obstetrics“, „labor“, „labour“, „delivery“, „neonate“, „newborn“, „child“, „baby“, „infant“, „fetus“, „fetal“, „opioid“ und „opiate“ sowie zusätzlich eine MeSH Terms Suche in PubMed durchgeführt.
Ergebnisse Von 355 potenziell relevanten Studien wurden 23 Studien in diese Arbeit eingeschlossen. Die Studien variierten stark in Qualität, Stichprobengröße und Outcome-Kriterien. Das neonatale Outcome war häufig nur ein sekundärer Endpunkt. Selten wurden signifikante Unterschiede bezogen auf das Outcome der Neugeborenen zwischen den verschiedenen systemischen Opioiden oder im Vergleich zu Kontrollgruppen berichtet. In 12 Studien wurden die APGAR-Werte der Neugeborenen zwischen Behandlungsgruppen verglichen, wobei sich bei 10 (83%) dieser Studien keine Unterschiede zeigten.
Diskussion/Ausblick Die Evidenzlage zu Auswirkungen geburtshilflicher Analgesie mit systemischen Opioiden ist insgesamt gering und Studien zum Langzeit-Outcome von Neugeborenen fehlen. Auch die Frage, ob eine postnatale Überwachung der Neugeborenen notwendig ist, kann nicht klar beantwortet werden. Studien mit prospektivem Studiendesign sollten durchgeführt werden.