18,419 research outputs found
A predictive pan-European economic and production dispatch model for the energy transition in the electricity sector
The energy transition is well underway in most European countries. It has a
growing impact on electric power systems as it dramatically modifies the way
electricity is produced. To ensure a safe and smooth transition towards a
pan-European electricity production dominated by renewable sources, it is of
paramount importance to anticipate how production dispatches will evolve, to
understand how increased fluctuations in power generations can be absorbed at
the pan-European level and to evaluate where the resulting changes in power
flows will require significant grid upgrades. To address these issues, we
construct an aggregated model of the pan-European transmission network which we
couple to an optimized, few-parameter dispatch algorithm to obtain time- and
geographically-resolved production profiles. We demonstrate the validity of our
dispatch algorithm by reproducing historical production time series for all
power productions in fifteen different European countries. Having calibrated
our model in this way, we investigate future production profiles at later
stages of the energy transition - determined by planned future production
capacities - and the resulting interregional power flows. We find that large
power fluctuations from increasing penetrations of renewable sources can be
absorbed at the pan-European level via significantly increased electricity
exchanges between different countries. We identify where these increased
exchanges will require additional power transfer capacities. We finally
introduce a physically-based economic indicator which allows to predict future
financial conditions in the electricity market. We anticipate new economic
opportunities for dam hydroelectricity and pumped-storage plants.Comment: 6 pages, 8 figure
On the Buchsbaum index of rank two vector bundles on P3
We classify rank two vector bundles on P3 with Buchsbaum index equal to three
and also give some results on the H1-module of "negative instanton"bundles.Comment: Submitted to the proceedings of the Pau-Trieste conferences Vector
bundles day
How fast can one overcome the paradox of the energy transition? A physico-economic model for the European power grid
The paradox of the energy transition is that the low marginal costs of new
renewable energy sources (RES) drag electricity prices down and discourage
investments in flexible productions that are needed to compensate for the lack
of dispatchability of the new RES. The energy transition thus discourages the
investments that are required for its own harmonious expansion. To investigate
how this paradox can be overcome, we argue that, under certain assumptions,
future electricity prices are rather accurately modeled from the residual load
obtained by subtracting non-flexible productions from the load. Armed with the
resulting economic indicator, we investigate future revenues for European power
plants with various degree of flexibility. We find that, if neither carbon
taxes nor fuel prices change, flexible productions would be financially
rewarded better and sooner if the energy transition proceeds faster but at more
or less constant total production, i.e. by reducing the production of thermal
power plants at the same rate as the RES production increases. Less flexible
productions, on the other hand, would see their revenue grow more moderately.
Our results indicate that a faster energy transition with a quicker withdrawal
of thermal power plants would reward flexible productions faster.Comment: 13 pages, 11 figures and 2 table
Epitope prediction improved by multitask support vector machines
Motivation: In silico methods for the prediction of antigenic peptides
binding to MHC class I molecules play an increasingly important role in the
identification of T-cell epitopes. Statistical and machine learning methods, in
particular, are widely used to score candidate epitopes based on their
similarity with known epitopes and non epitopes. The genes coding for the MHC
molecules, however, are highly polymorphic, and statistical methods have
difficulties to build models for alleles with few known epitopes. In this case,
recent works have demonstrated the utility of leveraging information across
alleles to improve the performance of the prediction. Results: We design a
support vector machine algorithm that is able to learn epitope models for all
alleles simultaneously, by sharing information across similar alleles. The
sharing of information across alleles is controlled by a user-defined measure
of similarity between alleles. We show that this similarity can be defined in
terms of supertypes, or more directly by comparing key residues known to play a
role in the peptide-MHC binding. We illustrate the potential of this approach
on various benchmark experiments where it outperforms other state-of-the-art
methods
Kernel methods for in silico chemogenomics
Predicting interactions between small molecules and proteins is a crucial
ingredient of the drug discovery process. In particular, accurate predictive
models are increasingly used to preselect potential lead compounds from large
molecule databases, or to screen for side-effects. While classical in silico
approaches focus on predicting interactions with a given specific target, new
chemogenomics approaches adopt cross-target views. Building on recent
developments in the use of kernel methods in bio- and chemoinformatics, we
present a systematic framework to screen the chemical space of small molecules
for interaction with the biological space of proteins. We show that this
framework allows information sharing across the targets, resulting in a
dramatic improvement of ligand prediction accuracy for three important classes
of drug targets: enzymes, GPCR and ion channels
Analytical matrix elements of the Uehling potential in three-body systems, and applications to exotic molecules
Exact analytical expressions for the matrix elements of the Uehling potential
in a basis of explicitly correlated exponential wave functions are presented.
The obtained formulas are then used to compute with an improved accuracy the
vacuum polarization correction to the binding energy of muonic and pionic
molecules, both in a first-order perturbative treatment and in a
nonperturbative approach. The first resonant states lying below the n=2
threshold are also studied, by means of the stabilization method with a real
dilatation parameter
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