bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diving safety alarm based on the techniques of machine learning
Authors: Ling Ying , Yu Jo‐Hung , Shen Chih‐Chien , Wu Chien‐Hung 
Published: June 2021

AbstractMany countries actively promote the benefits of sports; in particular, water sports are popular among the younger generation. However, despite the mature development of equipment in diving, it requires relevant training to avoid decompression sickness. Sometimes when divers encounter emergencies and they may fail to alert the coach or other companions for rescues. Currently, some divers wear emergency equipment when conducting the exercise; yet, the cost is relatively high, and the operation is complicated that people tend to forget the process when facing emergencies. This article aims to develop a wearable device that has a safety alarm function based on the technique of machine learning. The features of the suggested device are as follows: (1) cost‐effective detectors for monitoring divers' conditions; (2) a combination of an Automatic Identification System (AIS) with a Global Positioning System (GPS) to send a safety alarm with the location of the diver; (3) utilize Bluetooth communication to detect if a diver left the safety range set by the coach; (4) the machine learning technique judges the health status of the diver; (5) the wearable device connects with swim goggles to deliver danger alarms, which enables divers to notice dangerous situations from the lights on the goggles. The approach suggested in this article primarily utilizes wearable devices to ensure divers' safety. The key feature of this device can prevent divers from sweeping away by currents or swimming into risky areas; meanwhile, the device can detect the risk of decompression sickness. The research executed an experiment to verify the design, and the results have proven the feasibility of the study. Additionally, with the cost‐effective detectors installed on the device, the presented equipment has the potential to make it universal and increase the safety of divers.
Imbalance‐based primary frequency control for converter‐fed microgrid
Authors: Suh Jaewan , Lee Jaehyeong , Jung Seungmin , Yoon Minhan 
Published: June 2021

AbstractFrequency droop control is a simple and effective frequency control method. However, it is not appropriate as a primary frequency control for microgrids with energy storage systems and voltage source converters (VSCs) owing to their slow response speed. In addition, it is difficult to determine the grid balance only with frequency deviation. In this paper, a new converter‐fed microgrid primary frequency control method based on the estimated active power imbalance for fast response and less variability in the transmission system is proposed. The active power imbalance is estimated via frequency deviation, frequency drop speed and the modified swing equation. The estimated imbalance indicates the status of the power imbalance more quickly and accurately than the frequency deviation. The proposed method does not require communication devices, responds quickly to frequency drops, and prevents unnecessary operation of the grid‐connected VSC because it uses the estimated imbalance instead of the frequency or angle for droop control. Simulation results show that the proposed method is significantly faster than frequency droop control methods, improves the rate of change of frequency and frequency nadir and reduces variability in the transmission system.
High energy flash X‐ray image restoration using region extrema and kernel optimization
Authors: Wang Xiaolin , Li Qingwu , Xu Jinxin 
Published: June 2021

AbstractThe quality of high energy flash X‐ray images is crucial to the high‐precision diagnosis of object density. High energy flash X‐ray radiography is susceptible to the system blur, which usually causes the poor quality of static images. In response to this, a novel restoration algorithm using region extrema and kernel optimization (REKO) is presented. Based on the observation that the region extrema distribution of blurred high energy flash X‐ray images deviates from opposite ends of image grey domain, the sparseness‐inducing prior for regularizing image region extrema is applied to construct the restoration model. Considering the sparse characteristics of blur kernels, the sparseness‐inducing regularization is incorporated to constrain blur kernels in the restoration model. The non‐convex and non‐linear objective function is gradually minimized through energy alternating minimization and dually linear approximation. Furthermore, a continuity enforced kernel optimization algorithm is proposed to estimate more accurate blur kernels. The discontinuous kernel elements are suppressed by extracting the main structure of blur kernels and constructing kernel continuity function in cross windows. Experimental results demonstrate that our algorithm can more accurately estimate blur kernels and achieve restoration results with sharper edges on high energy flash X‐ray images.
The OTELO survey
Authors: Navarro Martínez Rocío , Pérez-García Ana María , Pérez-Martínez Ricardo , Cerviño Miguel , Gallego Jesús , Bongiovanni Ángel , Barrufet Laia , Nadolny Jakub , Cedrés Bernabé , Cepa Jordi , Alfaro Emilio , Castañeda Héctor O. , de Diego José A. , González-Otero Mauro , Jesús González J. , González-Serrano J. Ignacio , Lara-López Maritza A. , Padilla Torres Carmen P. , Sánchez-Portal Miguel 
Published: June 2021

Aims.We study a sample of Hβemission line sources atz ∼ 0.9 to identify the star-forming galaxies sample and characterise them in terms of line luminosity, stellar mass, star formation rate, and morphology. The final aim is to obtain the Hβluminosity function of the star-forming galaxies at this redshift.Methods.We used the red tunable filter of the instrument Optical System for Imaging low Resolution Integrated Spectroscopy (OSIRIS) at Gran Telescopio de Canarias to obtain the pseudo spectra of emission line sources in the OTELO field. From these pseudo spectra, we identified the objects with Hβemission. As the resolution of the pseudo spectra allowed us to separate Hβfrom [O III], we were able to derive the Hβflux without contamination from its adjacent line. Using data from the extended OTELO catalogue, we discriminated AGNs and studied the star formation rate, the stellar mass, and the morphology of the star-forming galaxies.Results.We find that our sample is located on the main sequence of star-forming galaxies. The sources are morphologically classified, mostly as disc-like galaxies (76%), and 90% of the sample are low-mass galaxies (M* < 1010 M⊙). The low-mass star-forming galaxies atz ∼ 0.9 that were detected by OTELO present similar properties as low-mass star-forming galaxies in the local universe, suggesting that these kinds of objects do not have a favorite epoch of formation and star formation enhancement fromz ∼ 1 to now. Our sample of 40 Hβstar-forming galaxies include the faintest Hβemitters detected so far. This allows us to constrain the faint end of the luminosity function for the Hβline alone with a minimum luminosity of logL = 39 erg s−1, which is a hundred times fainter than previous surveys. The dust-corrected OSIRIS Tunable Emission Line Object survey (OTELO) Hβluminosity function established the faint-end slope asα = −1.36 ± 0.15. We increased the scope of the analysis to the bright end by adding ancillary data from the literature, which was not dust-corrected in this case. The obtained slope for this extended luminosity function isα = −1.43 ± 0.12.
X-ray emission from BH+O star binaries expected to descend from the observed galactic WR+O binaries
Authors: Sen K. , Xu X.-T. , Langer N. , El Mellah I. , Schürmann C. , Quast M. 
Published: June 2021

Context. In the Milky Way, ∼18 Wolf-Rayet+O star (WR+O) binaries are known with estimates of their stellar and orbital parameters. Whereas black hole+O star (BH+O) binaries are thought to evolve from WR+O binaries, only one such system is known in the Milky Way. To resolve this disparity, it was suggested recently that upon core collapse, the WR stars receive large kicks such that most of the binaries are disrupted.
Aims. We reassess this issue, with a particular emphasis on the uncertainty in predicting the X-ray emission from wind-accreting BHs in BH+O binaries, which is key to identifying such systems.
Methods. BH+O systems are thought to be X-ray bright only when an accretion disk forms around the BHs. We followed the methodology of previous work and applied an improved analytic criterion for the formation of an accretion disk around wind accreting BHs. We then used stellar evolutionary models to predict the properties of the BH+O binaries which are expected to descend from the observed WR+O binaries if the WR stars would form BHs without a natal kick.
Results. We find that disk formation sensitively depends on the O stars’ wind velocity, the amount of specific angular momentum carried by the wind, the efficiency of angular momentum accretion by the BH, and the spin of the BH. We show that whereas the assumption of a low wind velocity may lead to the prediction that most of the BH+O star binaries will have an extended X-ray bright period, this is not the case when typical wind velocities of O stars are considered. We find that a high spin of the BH can boost the duration of the X-ray active phase as well as the X-ray brightness during this phase. This produces a strong bias for detecting high mass BH binaries in X-rays with high BH spin parameters.
Conclusions. We find that large BH formation kicks are not required to understand the sparsity of X-ray bright BH+O stars in the Milky Way. Probing for a population of X-ray silent BH+O systems with alternative methods can likely inform us about BH kicks and the necessary conditions for high energy emission from high mass BH binaries.
Necrosis or Flap Loss After Deep Inferior Epigastric Perforator Reconstruction: Impact of Perforators and Recipient Vessels
Authors: Palve Johanna S. , Luukkaala Tiina H. , Kääriäinen Minna T. 
Published: June 2021

AbstractBackground The aim of this study is to analyze the impact of the number and location of perforators harvested and the recipient vessels used on deep inferior epigastric perforator (DIEP) flap survival and the occurrence of flap necrosis requiring re-operation.Patients and Methods Four hundred and seventy-one DIEP flap reconstructions, performed between January 2008 and December 2019, were retrospectively analyzed.Results Flap necrosis requiring re-operation was observed in 40 (9%) of flaps and total flap loss rate was 1% (n = 6). No significant differences were observed between internal mammary vessels (IMV, n = 287, 61%) and thoracodorsal vessels (TDV, n = 184, 39%) regarding postoperative re-anastomosis (p = 0.529) or flap survival (p = 0.646). Intraoperative conversion from IMV to TDV was performed on 64 (14%) patients. TDV were more commonly associated with problems in preparation of the vessels than IMV (p < 0.001). Second vein anastomosis was performed on 18 (4%) patients. In total, 81 flaps (17%) had one perforator, 165 (35%) had two, 218 (46%) had three to five, and 7 (2%) had more than five perforators. Flaps with three to five perforators were more commonly associated with flap necrosis (p < 0.001) than flaps with one or two perforators. Independent factors associated with necrosis were body mass index (BMI) > 30 (odds ratio [OR]: 2.28; 95% confidence interval: 1.06–4.91, p = 0.035) and perforator/s located on the lateral row (OR: 3.08, 95% CI 1.29–7.33, p = 0.011).Conclusion We conclude that the occurrence of flap necrosis requiring re-operation may be higher in DIEP flaps with more than two perforators or perforator/s located on the lateral row and in obese patients. Neither the recipient vessels used nor the number of perforators harvested had any impact on the flap survival rate.
Are the First and Second Hip in Staged Bilateral Total Hip Arthroplasty Equal? A Hospital Adverse Event and Perioperative Risk Comparison
Authors: Villa Jesus M. , Pannu Tejbir S. , Higuera Carlos A. , Suarez Juan C. , Patel Preetesh D. , Barsoum Wael K. 
Published: June 2021

AbstractHospital adverse events remain a significant issue; even “minor events” may lead to increased costs. However, to the best of our knowledge, no previous investigation has compared perioperative events between the first and second hip in staged bilateral total hip arthroplasty (THA). In the current study, we perform such a comparison. A retrospective chart review was performed on a consecutive series of 172 patients (344 hips) who underwent staged bilateral THAs performed by two surgeons at a single institution (2010–2016). Based on chronological order of the staged arthroplasties, two groups were set apart: first-staged THA and second-staged THA. Baseline-demographics, length of stay (LOS), discharge disposition, hospital adverse events, and hospital transfusions were compared between groups. Statistical analyses were performed using independent t-tests, Fisher's exact test, and/or Pearson's chi-squared test. The mean time between staged surgeries was 465 days. There were no significant differences in baseline demographics between first-staged THA and second-staged THA groups (patients were their own controls). The mean LOS was significantly longer in the first-staged THA group than in the second (2.2 vs. 1.8 days; p < 0.001). Discharge (proportion) to a facility other than home was noticeably higher in the first-staged THA group, although not statistically significant (11.0 vs. 7.6%; p = 0.354). The rate of hospital adverse events in the first-staged THA group was almost twice that of the second (37.2 vs. 20.3%; p = 0.001). There were no significant differences in transfusion rates. However, these were consistently better in the second-staged THA group. When compared with the first THA, our findings suggest overall shorter LOS and fewer hospital adverse events following the second.
Level of Evidence Level III.
Testing the effects of Facebook usage in an ethnically polarized setting
Authors: Asimovic Nejla , Nagler Jonathan , Bonneau Richard , Tucker Joshua A. 
Published: June 2021

SignificanceAmid growing belief that social media exacerbates polarization, little is known about the causal effects of social media on ethnic outgroup attitudes. Through an experiment in Bosnia and Herzegovina where users refrained from Facebook usage during 1 wk of heightened identity salience, we find that—counter expectations—people who deactivated their accounts reported lower outgroup regard than the group that remained active, but this effect was likely conditional on the level of ethnic heterogeneity of respondents’ residence. Additionally, we replicate findings from a study on US users: Deactivation led to a decrease in news knowledge and suggestive improvements in subjective wellbeing. Our findings bring nuance to popular beliefs, frequently dichotomous and simplistic, of social media’s impact on societal dynamics.
Nonlinear Finite Element Analysis of RC Beam Exposed To Fire With and Without CFRP Strengthening
Authors: Obied Wissam , Stematiu Dan 
Published: June 2021

Abstract
The Nonlinear finite element (FE) model can accurately predict the behaviour of reinforced concrete (RC) with the RC beam’s safety with and without CFRP that is designed for resistance against high temperatures. Transient thermal finite element analysis is performed using the ANSYS software. The beam was subjected to a short-duration, high-intensity (SDHI) fire at the bottom and side surfaces, in the form of transient temperatures versus time, whereas maintaining constant transversal loading on the highest body. The validation of the finite element model without CFRP is confirmed by comparing the results with experimental testing results that are carried out at similar model conditions within the same geometry, reinforced, and boundary conditions. After that, added the carbon fiber reinforced polymer sheet (CFRP) at the bottom and side surfaces of the RC beam during fire exposure as a parametric study to investigate the effect of CFRP on the strength and stiffness of the RC beam at high temperatures. The results showed that CFRP strengthening would have a significant impact on RC beam stiffness.
The Status Quo of Renewable Energy Development and Utilization and the Prospects of Industrial Development
Authors: Liu Lei , Xiao Hanli , Shen Liang 
Published: June 2021

Abstract
Nowadays, the development and utilization of the renewable energy is more and more favored by countries all over the world for the purpose of solving the contradiction between the energy demand and the environmental protection. The application of renewable energy (including hydraulic energy, ocean energy, wind energy, solar energy, biomass energy and hydrogen energy) in our country develops rapidly and promotes the development of related industries at present. The optimization of energy structure will be realized, and the application prospect of the renewable energy industry will be broadened under the guidance of carbon peak and requirements of carbon neutral in the future.
Design of flexibility mechanism for electricity market to promote the consumption of new energy
Authors: Fang Yin , Xie Yi , Shi Yichuan 
Published: June 2021

Abstract
With the development of new energy, it is an irresistible trend for the demand side to consume new energy on a large scale and in a high proportion. At present, China’s installed capacity of new energy is growing rapidly, but the flexibility of the power system is insufficient, new energy consumption is difficult, and a large number of abandoned wind and light phenomena appear. In view of the high proportion of new energy consumption in the current environment, this paper designs the overall framework of the flexibility mechanism of the power market to promote new energy consumption, and puts forward the benefits of various market mechanisms in improving flexibility and promoting new energy consumption. Based on each market mechanism, the contribution index is put forward, the role of each market mechanism is analyzed quantitatively, and the considerable benefit of the market flexibility mechanism in promoting the consumption of new energy is proved by an example.
The Development of Integrated Centralized Control Platform for Electricity Meter Verification Device
Authors: Yan Liu , Jing-fen Zhang , Ying Yi , Jiang-ying Qin , Ji-ye Qin 
Published: June 2021

Abstract
The verification of power equipment in power grid is one of the basic guarantees to ensure the normal operation of power grid system. It is necessary to carry on the related verification to the electric power equipment of different specifications and models to ensure the functions, performance and stability of the equipment, so as to ensure the normal, safe and accurate operation of the power grid system. In this paper, a kind of electric energy meter verification device is designed. The verification platform can control the electric energy meter verification devices of different manufacturers and different models to carry out automatic verification of electric energy metering equipment. The verification platform is highly expandable, so long as the driver of the control device is implemented according to the interface method stipulated by the verification platform, the device can be seamlessly integrated into the verification platform.
Analysis of foundation bearing capacity and structural stability of suction bucket for offshore wind power
Authors: Xu Zhang 
Published: June 2021

Abstract
The large-scale wide and shallow bucket foundation of offshore wind power has a unique bucket top bearing mode, and the bucket foundation is provided with partition plates, which has greater bearing capacity as a whole. By numerical method, the solid and structural elements such as bucket body, rib plate connector and silo plate, as well as bucket-soil contact element are established, and the real three-dimensional complex model of bucket foundation and foundation soil is constructed in detail. The nonlinear contact calculation of bucket foundation under the combined loading modes such as horizontal load, wave force, vertical load and bending moment are simulated, and the deformation, bearing characteristics and safety of suction bucket are analyzed. The ultimate bearing capacity of foundation under horizontal load, vertical load and bending moment are calculated by Flac3d finite difference method, which provide reference for the foundation structure selection, bucket foundation design, implementation and safety evaluation of offshore wind farm projects.
Numerical simulation of fluid-solid coupling of stress failure characteristics of floor in coal mining face
Authors: Wu Weizheng , Wang ZHonghua 
Published: June 2021

Abstract
In order to explore the characteristics of floor stress failure in the mining face under the action of non-uniform water pressure, a fluid-solid coupling model of non-uniform water-bearing area was established. FLAC-3D simulation software was used to simulate and analyze the changes in the initial mining stage, the sudden stress increase stage, the stress slow increase stage, and the stable stress stage during the mining process of the working face, and the failure characteristics of the floor were analyzed. It reveals the reasons why water inrush accidents are likely to occur at the front of the working face, which has a certain significance for understanding the mechanism of water inrush from the floor.
Research on the Operation Measurement and Evaluation Method of Retail Packages under the Background of Electricity Market
Authors: Fei Wenjing , Tang Wei , Chen Ling , Ding Wenjiao , Yang Saite 
Published: June 2021

Abstract
With the liberalization of the electricity market, building a diversified and open competitive electricity retail market has become the focus of market reform and development. In the initial stage of the the retail market, the operating status of retail companies is an important evidence for the analysis of the current development of the retail market and the formulation of relevant rules. This paper designs a retail allocation method and proposes different business calculation and analysis methods based on 9 different types of retail packages in Yunnan electricity retail market. Based on a two-tier evaluation index system for retail packages and the electricity sales company, the FCE method combined with the AHP is used to evaluate the operating states of the electricity sales company and the retail packages.
Study on Extraction of Flavonoe Coated in Physalis alkekengi L
Authors: Li Ci Li , Huang Yu Yang , Yu Shi You 
Published: June 2021

Abstract
Flavones were extracted from Physalis alkekengi L. coating by ultrasonic method. Effects of material ratio, concentration of alcohol, ultrasonic time, temperature and power on the yield of flavones were studied. Optimal extracting conditions were determined through single factor and orthogonal experiments. The results showed that when ultrasonic power was 450 W, ratio of material to liquid was 1:50, the optimal extracting conditions were as follows: concentration of alcohol 50%, ultrasonic time 20 min, ultrasonic temperature 80°C, under above conditions, extraction yield of flavones was 1.93%. which approximated the predicted value of 2.05%.