bluuebunny/crossref_metadata_2025_split huggingface dataset:
The readiness of industry for a transformative recovery from COVID 19
Authors: Fankhauser Sam , Kotsch Raphaela , Srivastav Sugandha 
Published: December 2020

Non-technical summary
Many countries are committed to emerge from COVID 19 on a more sustainable environmental footing. Here we explore what such a structurally transformative recovery would mean for the manufacturing sector of 14 major economies. We find that all countries have zero-carbon growth opportunities post-COVID and comparative advantages in some sectors, but industrialised countries and the East Asian economies, especially South Korea, appear best positioned, thanks a push in low-carbon innovation that predates the pandemic.
In‐situ Mass Balance Estimates Offshore Costa Rica
Authors: Edwards J. , Kluenser Jared , Silver Eli , Lauer Rachel , Bangs Nathan , Boston Brian 
Published: December 2020

AbstractThe Costa Rican convergent margin has been considered a type erosive margin, with erosional models suggesting average losses up to −153 km3/km/m.y. However, three‐dimensional (3D) seismic reflection and Integrated Ocean Drilling Program data collected offshore the Osa Peninsula images accretionary structures and vertical motions that conflict with the forearc basal erosion model. Here we integrate such data to do an in‐situ accounting of material transfer at the plate boundary across the outermost 10 km of the forearc, characterized by active and inactive megathrusts. Our in‐situ budget finds an approximate balance between sediment recycling via accretion and underplating, 0.7–2.3 km3/km/m.y., and basal erosion, 0.7 km3/km/m.y., while subducting sediment volumes, 7.8 km3/km/m.y., greatly outpace either material transfer volumes. These budget results differ significantly from published estimates based on simple proxies of trench axis deflection and slope subsidence. These budget results are the summation of thin incoming hemipelagic sediments that variably accrete along the deformation front, underplating of hemipelagic sediments on the upthrown‐side and basal erosion on the downthrown‐side of active plate bending faulting landward of the trench axis, and sediment subduction primarily composed of pelagic sediments.
On the benefit of inter‐operator cooperation in C‐RAN
Authors: Kim Donggu , Sung Ki Won , Koh Jeongwan , Kang Joonhyuk 
Published: December 2020

AbstractCooperation of co‐located mobile network operators can provide potential benefits for the capacity expansion without further densification of radio nodes. However, such benefits need to be scrutinised for coexisting cloud radio access network (C‐RAN) operators because the inter‐operator cooperation may compromise the superb interference coordination capability that each C‐RAN has. Furthermore, altering C‐RAN infrastructure for the cooperation incurs a high investment cost. In this paper, quantitative gain of inter‐operator coordination strategies is evaluated to provide the C‐RAN operators with a guideline on their cooperation decisions. The coordination strategies encompass dynamic user association and the spectrum sharing which aim at maximising the total user throughput. A heuristic algorithm is proposed that reduces the computational burden of the coordination significantly. Numerical results suggest that the inter‐operator cooperation is beneficial particularly when the network size of each operator tends to be highly asymmetric. It is also verified that the users who belong to smaller network attain more coordination gains.
MIMO channel estimation with arbitrary angle of arrival incident power spectrum for wireless communications
Authors: Zhou Jie , Wang Xueying , Jiang Hao , Sasaki Shigenobu , Shao Genfu 
Published: December 2020

AbstractThis study proposes an approximate algorithm for the arbitrary angle of arrival (AoA) incident power spectrum in wireless environments. The approach expands approximate algorithms for small angles to the large‐angle AoA PDF. To achieve this, the fading correlation of wireless channels is calculated and derived for various theoretical fittings and measured data. Then, the multiple‐input multiple‐output (MIMO) channel model is reconstructed for special environments using spatial fading correlation (SFC). Following this, the approximate algorithm and its complexity are investigated in depth in the SFC of multi‐antenna arrays with small AoA angles under uniform, Gaussian, and Laplacian distributions, which can function in macrocell and microcell environments. Further, the closed form formulas for SFC are derived for the small angle spread of incident signals. The formulas are extended to simulate these cases with large angle spreads, which result in an increasing calculation complexity, particularly for the actual measured results. The selection of the number of samples and the weighting coefficient in the large angle spreads and its fitting accuracy are considered in detail. Based on this relationship, the properties of the temporal correlation and channel of the MIMO uniform linear array are studied and discussed.
Shaped offset 8PSK and coded shaped offset 8PSK with improved spectrum efficiency for satellite communication
Authors: Liu Yue , Cao Ning , Mao Minghe , Li Gang 
Published: December 2020

AbstractThe development of satellite communication (SATCOM) puts forward demanding requirements for the modulation methods' spectral efficiency (SE) which is mainly subject to the pulse shaping and the utilisation of signal space. To date, there has rare consideration on the modification of high order phase shift keying (HOPSK) to gain higher SE in this literature. In this work, shaped offset 8PSK (SO8PSK) is developed which splits 8PSK bit transmission into three offset paths and then loads the shaping pulse onto them. The obtained modulation with continuous constrained phase and constant envelope is shown to increase the SE compared to 8PSK by about 43% and is applicable for the nonlinear and band‐limited SATCOM environment. To address the HOPSK inherent complexity, a simplified receiver is provided to reduce about two‐third matched filters. Additionally, the iterative encoding of SO8PSK is presented and it is used as the inner code of serial concatenated coding (SCC) . This modification method can be seen as a starting point to the better use of HOPSK for SATCOM.
A new blind image conversion complexity metric for intelligent CMOS image sensors
Authors: Elmezayen Mohamed R. , Ay Suat U. 
Published: December 2020

AbstractMany algorithms have been developed for complementary metal–oxide–semiconductor (CMOS) image sensors to speed up analogue‐to‐digital (A‐to‐D) conversion of captured images. However, there is no objective blind‐image quality metric available to compare and quantify the quality and effectiveness of these speed‐up algorithms. In this work, we developed a blind‐image quality and complexity metric for this purpose. The proposed metric relies on counting the successive zeros in a code histogram. The proposed metric is called the conversion complexity metric (CCM). The CCM is designed to quantify how complex, and to predict how much time and power consuming a captured image is for A‐to‐D conversion, mainly by integrating (ramp) type A‐to‐D converter used in column‐parallel architectures of a CMOS image sensor (CIS). The proposed metric, CCM, is tested for linearity, monotonicity, and sensitivity to many types of introduced distortion. The CCM is compared with other no‐reference and full‐reference image quality and complexity metrics. It accomplished, for brightness change distortion, 99% linearity and 316% sensitivity, providing a computationally efficient blind‐image quality metric that no other metrics provide for CIS to intelligently adjust and optimise on‐chip analogue and digital signal processing.
Size and structures of disks around very low mass stars in the Taurus star-forming region
Authors: Kurtovic N. T. , Pinilla P. , Long F. , Benisty M. , Manara C. F , Natta A. , Pascucci I. , Ricci L. , Scholz A. , Testi L. 
Published: December 2020

Context. The discovery of giant planets orbiting very low mass stars (VLMS) and the recent observed substructures in disks around VLMS is challenging planet formation models. Specifically, radial drift of dust particles is a catastrophic barrier in these disks, which prevents the formation of planetesimals and therefore planets.
Aims. We aim to estimate if structures, such as cavities, rings, and gaps, are common in disks around VLMS and to test models of structure formation in these disks. We also aim to compare the radial extent of the gas and dust emission in disks around VLMS, which can give us insight about radial drift.
Methods. We studied six disks around VLMS in the Taurus star-forming region using ALMA Band 7 (~340 GHz) at a resolution of ~0.1″. The targets were selected because of their high disk dust content in their stellar mass regime.
Results. Our observations resolve the disk dust continuum in all disks. In addition, we detect the 12CO (J = 3−2) emission line in all targets and 13CO (J = 3−2) in five of the six sources. The angular resolution allows the detection of dust substructures in three out of the six disks, which we studied by using UV-modeling. Central cavities are observed in the disks around stars MHO 6 (M 5.0) and CIDA 1 (M 4.5), while we have a tentative detection of a multi-ringed disk around J0433. We estimate that a planet mass of ~0.1 MJup or ~0.4 MSaturn is required for a single planet to create the first gap in J0433. For the cavities of MHO 6 and CIDA 1, a Saturn-mass planet (~0.3 MJup) is required. The other three disks with no observed structures are the most compact and faintest in our sample, with the radius enclosing 90% of the continuum emission varying between ~13 and 21 au. The emission of 12CO and 13CO is more extended than the dust continuum emission in all disks of our sample. When using the 12CO emission to determine the gas disk extension Rgas, the ratio of Rgas∕Rdust in our sample varies from 2.3 to 6.0. One of the disks in our sample, CIDA 7, has the largest Rgas∕Rdust ratio observed so far, which is consistent with models of radial drift being very efficient around VLMS in the absence of substructures.
Conclusions. Given our limited angular resolution, substructures were only directly detected in the most extended disks, which represent 50% of our sample, and there are hints of unresolved structured emission in one of the bright smooth sources. Our observations do not exclude giant planet formation on the substructures observed. A comparison of the size and luminosity of VLMS disks with their counterparts around higher mass stars shows that they follow a similar relation.
Speed limits for radiation-driven SMBH winds
Authors: Luminari A. , Nicastro F. , Elvis M. , Piconcelli E. , Tombesi F. , Zappacosta L. , Fiore F. 
Published: December 2020

Context.Ultra-fast outflows (UFOs) have become an established feature in analyses of the X-ray spectra of active galactic nuclei (AGN). According to the standard picture, they are launched at accretion disc scales with relativistic velocities, up to 0.3−0.4 times the speed of light. Their high kinetic power is enough to induce an efficient feedback on a galactic scale, possibly contributing to the co-evolution between the central supermassive black hole (SMBH) and the host galaxy. It is, therefore, of paramount importance to gain a full understanding of UFO physics and, in particular, of the forces driving their acceleration and the relation to the accretion flow from which they originate.Aims.In this paper, we investigate the impact of special relativity effects on the radiative pressure exerted onto the outflow. The radiation received by the wind decreases for increasing outflow velocity,v, implying that the standard Eddington limit argument has to be corrected according tov. Due to the limited ability of the radiation to counteract the black hole gravitational attraction, we expect to find lower typical velocities with respect to the non-relativistic scenario.Methods.We integrated the relativistic-corrected outflow equation of motion for a realistic set of starting conditions. We concentrated on a range of ionisations, column densities, and launching radii consistent with those typically estimated for UFOs. We explore a one-dimensional, spherical geometry and a three-dimensional setting with a rotating, thin accretion disc.Results.We find that the inclusion of special relativity effects leads to sizeable differences in the wind dynamics and thatvis reduced up to 50% with respect to the non-relativistic treatment. We compare our results with a sample of UFOs from the literature and we find that the relativistic-corrected velocities are systematically lower than the reported ones, indicating the need for an additional mechanism, such as magnetic driving, to explain the highest velocity components. Finally, we note that these conclusions, derived for AGN winds, are generally applicable.
PI-RADS 2.1 – Image Interpretation: The Most Important Updates and Their Clinical Implications
Authors: Beyer Thomas , Schlemmer Heinz-Peter , Weber Marc-André , Thierfelder Kolja M. 
Published: December 2020

Background Multiparametric magnetic resonance imaging (MRI) of the prostate plays a central role in the diagnosis of patients with suspected prostate cancer. The increasing distribution and application of the guideline for the standardization of image acquisition, evaluation, and reporting (Prostate Imaging – Reporting and Data System, PI-RADS), which was updated in 2019 to version 2.1, contributes to the success of the technique.
Materials and Methods The most important updates of PI-RADS version 2.1 presented in 2019 compared to the previous version PI-RADS 2.0 are highlighted and interpreted with regard to their clinical implications.
Results PI-RADS version 2.1 aims to simplify the application of the scoring scheme without changing the basic concept of dominant sequences (DWI in the peripheral zone, T2 in the transition zone). Of particular importance are the increasing role of diffusion-weighted imaging in the transition zone, the now mandatory high b-value of at least 1400 s/mm2, and new information on the assessment of the central zone and the anterior fibromuscular stroma.
Conclusion PI-RADS version 2.1 published in 2019 addresses a number of changes to the previous version, including both the examination technique and image interpretation. Prospective clinical studies have yet to prove the extent to which the goals of reducing interreader variability and increasing the detection rate in the transition zone will be achieved.
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Effects of a cathode fall region on deposition rate of copper atoms in Dc plasma sputtering source
Authors: Yahya Khalid A 
Published: December 2020

Abstract
A theoretical investigation was carried out to show the effect of the length of the cathode fall region on the deposition rate of copper atoms on a substrate using dc plasma sputtering source. The effects of the discharge voltage (−1 to −3 kV) and argon gas pressure (1 × 10–2 to 5 × 10–1 mbar) on the length of the cathode fall region of the proposed plasma source were investigated. The flux energies of gas ions, neutral’s gas atoms and electrons in one dimension were calculated to determine the length of the cathode fall region, total current density and the rate of deposition of copper atoms. The results show that the length of the cathode fall region increases when low gas pressure is used at high values of the discharge voltage for the plasma source. There is also a relationship between the length of the cathode fall region and the rate of deposition of copper atoms on the substrate, where the deposition rate increased by 76% when the cathode fall length increased by 120% at the discharge voltage −3 kV and the pressure of gas 1 × 10–2 mbar.
New Observations with Gemini and GTC of the VHE Blazar KUV 00311–1938: About Its Redshift and Environment
Authors: Pichel A. , Donzelli C. , Rosa-Gonzalez D. , Alonso M. Fernandez , Rovero A. C. , Muriel H. , Mayya Y. D. , Aretxaga I. , González J. Becerra , Carramiñana A. , Mendez-Abreu J. , Vega O. , Terlevich E. , Terlevich R. J. 
Published: December 2020

Abstract
Extragalactic very-high-energy (VHE; E > 100 GeV) sources are unique objects to study the most powerful particle accelerators in nature, as active galactic nuclei are likely sources of ultra-high-energy cosmic rays. BL Lacertae blazars are the most frequent extragalactic objects found in the VHE gamma-ray catalogs. It is very difficult to estimate their redshifts, considering they have no strong enough optical spectral features, hence ∼20% of them have unknown or poorly constrained redshifts. KUV 00311–1938 is a VHE BL Lacertae blazar, with an uncertain redshift in the range of 0.5 < z < 0.98. We have obtained deep spectroscopy using Gemini and the GTC telescopes of KUV 00311–1938 and its surroundings with high signal-to-noise ratio in 2016–2017. The lack of features did not allow us to determine the spectroscopic redshift of KUV 00311–1938; nevertheless, we obtain a lower limit of z ≳ 0.475. We determined the redshifts of 41 galaxies observed in the field-of-view of the blazar and through a population study, identified three pairs and four groups consisting of 3 or 4 members with redshifts in the range z = 0.1468–0.4756. Due to the absence of a large group of galaxies, we could not associate KUV 00311–1938 with any of the groups detected.
Shannon unicity distance, ε-secrecy criterion and Holevo information in quantum cryptography
Authors: Arbekov I M , Molotkov S N 
Published: December 2020

Abstract
In this paper, we consider the relationship between C Shannon’s unicity distance, which is determined by the number of symbols of the encrypted message required to uniquely find the encryption key of the cryptosystem in information-theoretical sense, ε-secrecy criterion in quantum cryptography and Holevo information. A lower bound for the unicity distance for ε-secret keys in quantum cryptography is obtained. The relationship between unicity distance, ε-secrecy criterion in quantum cryptography and Holevo information is demonstrated.
Asymptotic learning curves of kernel methods: empirical data versus teacher–student paradigm
Authors: Spigler Stefano , Geiger Mario , Wyart Matthieu 
Published: December 2020

Abstract
How many training data are needed to learn a supervised task? It is often observed that the generalization error decreases as n
−β
where n is the number of training examples and β is an exponent that depends on both data and algorithm. In this work we measure β when applying kernel methods to real datasets. For MNIST we find β ≈ 0.4 and for CIFAR10 β ≈ 0.1, for both regression and classification tasks, and for Gaussian or Laplace kernels. To rationalize the existence of non-trivial exponents that can be independent of the specific kernel used, we study the teacher–student framework for kernels. In this scheme, a teacher generates data according to a Gaussian random field, and a student learns them via kernel regression. With a simplifying assumption—namely that the data are sampled from a regular lattice—we derive analytically β for translation invariant kernels, using previous results from the kriging literature. Provided that the student is not too sensitive to high frequencies, β depends only on the smoothness and dimension of the training data. We confirm numerically that these predictions hold when the training points are sampled at random on a hypersphere. Overall, the test error is found to be controlled by the magnitude of the projection of the true function on the kernel eigenvectors whose rank is larger than n. Using this idea we predict the exponent β from real data by performing kernel PCA, leading to β ≈ 0.36 for MNIST and β ≈ 0.07 for CIFAR10, in good agreement with observations. We argue that these rather large exponents are possible due to the small effective dimension of the data.
Design and implementation of silicon photomultiplier characterization setup for plasma physics applications
Authors: Baquero P A , Castañeda L F , Hernandez W A , Fuentes F , Cruz-Cardozo J L 
Published: December 2020

Abstract
Silicon photomultipliers are devices widely used and have direct applications in multiple scientific fields. Currently, the Universidad Antonio Nariño, Colombia, finance the research project Characterization of the coherent structures in the edge region of the plasma column in the TCABR tokamak using Langmuir probes in collaboration with Universidade de Sao Paulo, Brazil. In this project, we research plasma, and recently, we proposed a silicon photomultiplier to measure X-ray emissions from the plasma column. In this application, we have to know specific characteristics of silicon photomultiplier in behavior controlled conditions to establish its possible changes during exposure to radiation of plasma; one of silicon photomultiplier characteristics more important is gain due to its temperature dependence that generates disturbances on its response. To characterize the silicon photomultiplier in controlled conditions, we developed an analog integral proportional temperature automatic control system for the control of a silicon photomultiplier characterization setup that lets temperature variations from room temperature to 50°C reaching reference temperature in 1 minute with a steady state error less than 2% and overshoot of 5.53%.
Fractal analysis for estimating electricity demand through the application of Hurst’s re-staging exponent
Authors: Mesa F , Devia D M , Ospina R 
Published: December 2020

Abstract
This article presents a methodology for fractal analysis using the Hurst re-staging exponent for the generation prediction of a hydroelectric power plant. Which is an innovative technique to address this problem since literature usually performs it through classical and lately Bayesian statistical processes. The importance of the work implies amalgamation of concepts from fractal theory, chaos, phase space, delay time and Hurst exponent, necessary in the analysis that will determine an estimate of the future behavior of a chaotic series. Thus, the problem is addressed from the qualitative analysis through the theory of chaos.
Calibration of physicochemical parameters in aquaculture. A case study of tilapia breeding in Mozambique
Authors: Mulema S A , Prada-Núñez R , Mendoza-Lizcano S M 
Published: December 2020

Abstract
This paper discusses the adequacy of methods used in monitoring the aquatic environment in aquaculture. It is assumed that the strategy of controlling each of the environmental parameters by observing their compliance with the technical limits established in aquaculture is not sufficient to highlight all the aspects that may compromise the quality of the process. Therefore, the univariate methods that are usually used in water monitoring in aquaculture cannot show aspects of the process derived from the joint variability between the parameters. Thus, a multivariate method for monitoring the aquatic environment in aquaculture based on Hotelling’s T2 chart was proposed in this paper. Data on four physicochemical parameters (oxygen, temperature, pH and transparency) were collected from four aquatic species breeding ponds at the company Aquapesca in Mozambique, located in southeastern Africa. The correlation structure evidenced in the four physicochemical parameters analyzed showed a strong and positive relationship between temperature and pH, oxygen and transparency are inversely correlated. This correlation structure indicates that a possible reduction in water temperature also reduces the pH and vice versa, while a reduction in transparency implies an increase in dissolved oxygen. The multivariate method used shows the relationship between the parameters and the strategies to manage them, as well as the control strategy of the multivariate structure through Hotelling’s T2 chart, pointing out and correcting all the aspects that may compromise the quality of the breeding of the species in aquaculture.