105 research outputs found
Non-homogeneous Behaviour of the Spatial Distribution of Macrospicules
In this paper the longitudinal and latitudinal spatial
distribution of macrospicules is examined. We found a statistical
relationship between the active longitude determined by
sunspot groups and the longitudinal distribution of macrospicules.
This distribution of macrospicules shows an inhomogeneity and
non-axysimmetrical behaviour in the time interval from June
2010 until December 2012 covered by observations of the Solar
Dynamic Observatory (SDO) satellite. The enhanced positions
of the activity and its time variation has been calculated. The
migration of the longitudinal distribution of macrospicules shows
a similar behaviour as that of the sunspot groups
An efficient and principled method for detecting communities in networks
A fundamental problem in the analysis of network data is the detection of
network communities, groups of densely interconnected nodes, which may be
overlapping or disjoint. Here we describe a method for finding overlapping
communities based on a principled statistical approach using generative network
models. We show how the method can be implemented using a fast, closed-form
expectation-maximization algorithm that allows us to analyze networks of
millions of nodes in reasonable running times. We test the method both on
real-world networks and on synthetic benchmarks and find that it gives results
competitive with previous methods. We also show that the same approach can be
used to extract nonoverlapping community divisions via a relaxation method, and
demonstrate that the algorithm is competitively fast and accurate for the
nonoverlapping problem.Comment: 14 pages, 5 figures, 1 tabl
MARBLE: Music Audio Representation Benchmark for Universal Evaluation
In the era of extensive intersection between art and Artificial Intelligence (AI), such as image generation and fiction co-creation, AI for music remains relatively nascent, particularly in music understanding. This is evident in the limited work on deep music representations, the scarcity of large-scale datasets, and the absence of a universal and community-driven benchmark. To address this issue, we introduce the Music Audio Representation Benchmark for universaL Evaluation, termed MARBLE. It aims to provide a benchmark for various Music Information Retrieval (MIR) tasks by defining a comprehensive taxonomy with four hierarchy levels, including acoustic, performance, score, and high-level description. We then establish a unified protocol based on 14 tasks on 8 public-available datasets, providing a fair and standard assessment of representations of all open-sourced pre-trained models developed on music recordings as baselines. Besides, MARBLE offers an easy-to-use, extendable, and reproducible suite for the community, with a clear statement on copyright issues on datasets. Results suggest recently proposed large-scale pre-trained musical language models perform the best in most tasks, with room for further improvement. The leaderboard and toolkit repository are published at this https URL to promote future music AI research
Aqueous batteries as grid scale energy storage solutions
Energy storage technologies are required to make full use of renewable energy sources, and electrochemical
cells offer a great deal flexibility in the design of energy systems. For large scale electrochemical
storage to be viable, the materials employed and device production methods need to be low cost, devices
should be long lasting and safety during operation is of utmost importance. Energy and power densities
are of lesser concern. For these reasons, battery chemistries that make use of aqueous electrolytes are
favorable candidates where large quantities of energy need to be stored. Herein we describe several
different aqueous based battery chemistries and identify some of the research challenges currently
hindering their wider adoption. Lead acid batteries represent a mature technology that currently dominates
the battery market, however there remain challenges that may prevent their future use at the
large scale. Nickel–iron batteries have received a resurgence of interest of late and are known for their
long cycle lives and robust nature however improvements in efficiency are needed in order to make them
competitive. Other technologies that use aqueous electrolytes and have the potential to be useful in
future large-scale applications are briefly introduced. Recent investigations in to the design of nickel–iron
cells are reported with it being shown that electrolyte decomposition can be virtually eliminated by
employing relatively large concentrations of iron sulfide in the electrode mixture, however this is at the
expense of capacity and cycle life
HiRISE - High-Resolution Imaging and Spectroscopy Explorer - ultrahigh resolution, interferometric and external occulting coronagraphic science
Recent solar physics missions have shown the definite role of waves and magnetic fields deep in the inner corona, at the chromosphere-corona interface, where dramatic and physically dominant changes occur. HiRISE (High Resolution Imaging and Spectroscopy Explorer), the ambitious new generation ultra-high resolution, interferometric, and coronagraphic, solar physics mission, proposed in response to the ESA Voyage 2050 Call, would address these issues and provide the best-ever and most complete solar observatory, capable of ultra-high spatial, spectral, and temporal resolution observations of the solar atmosphere, from the photosphere to the corona, and of new insights of the solar interior from the core to the photosphere. HiRISE, at the L1 Lagrangian point, would provide meter class FUV imaging and spectro-imaging, EUV and XUV imaging and spectroscopy, magnetic fields measurements, and ambitious and comprehensive coronagraphy by a remote external occulter (two satellites formation flying 375 m apart, with a coronagraph on a chaser satellite). This major and state-of-the-art payload would allow us to characterize temperatures, densities, and velocities in the solar upper chromosphere, transition zone, and inner corona with, in particular, 2D very high resolution multi-spectral imaging-spectroscopy, and, direct coronal magnetic field measurement, thus providing a unique set of tools to understand the structure and onset of coronal heating. HiRISE’s objectives are natural complements to the Parker Solar Probe and Solar Orbiter-type missions. We present the science case for HiRISE which will address: i) the fine structure of the chromosphere-corona interface by 2D spectroscopy in FUV at very high resolution; ii) coronal heating roots in the inner corona by ambitious externally-occulted coronagraphy; iii) resolved and global helioseismology thanks to continuity and stability of observing at the L1 Lagrange point; and iv) solar variability and space climate with, in addition, a global comprehensive view of UV variability
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