8,560 research outputs found
An assessement of global energy resource economic potentials
This paper presents an assessment of global economic energy potentials for all major natural energy resources. This work is based on both an extensive literature review and calculations based onto natural resource assessment data. Economic potentials are presented in the form of cost-supply curves, in terms of energy flows for renewable energy sources, or fixed amounts for fossil and nuclear resources, using consistent energy units that allow direct comparisons to be made. These calculations take into account, and provide a theoretical framework for considering uncertainty in resource assessments, providing a novel contribution aimed at enabling the introduction of uncertainty into resource limitations used in energy modelling. The theoretical details and parameters provided in tables enable this extensive natural resource database to be adapted to any modelling framework for energy systems.This work was supported by the Three Guineas Trust, Conicyt (Comisio ́n Nacional de Investigacio ́n Cient ́ıfica y Tec- nolo ́gica, Gobierno de Chile) and the Ministerio de Energie, Gobierno de Chile
Virasoro Orbits, AdS_3 Quantum Gravity and Entropy
We analyse the canonical structure of AdS_3 gravity in terms of the coadjoint
orbits of the Virasoro group. There is one subset of orbits, associated to BTZ
black hole solutions, that can be described by a pair of chiral free fields
with a background charge. There is also a second subset of orbits, associated
to point-particle solutions, that are described by two pairs of chiral free
fields obeying a constraint. All these orbits admit K\"ahler quantization and
generate a Hilbert space which, despite of having ,
does not provide the right degeneracy to account for the Bekenstein-Hawking
entropy due to the breakdown of modular invariance. Therefore, additional
degrees of freedom, reestablishing modular invariance, are necessarily required
to properly account for the black hole entropy.Comment: LaTex file, 12 pages. New references adde
Incident detection using data from social media
This is an accepted manuscript of an article published by IEEE in 2017 IEEE 20th International Conference on Intelligent Transportation Systems (ITSC) on 15/03/2018, available online: https://ieeexplore.ieee.org/document/8317967/citations#citations
The accepted version of the publication may differ from the final published version.© 2017 IEEE. Due to the rapid growth of population in the last 20 years, an increased number of instances of heavy recurrent traffic congestion has been observed in cities around the world. This rise in traffic has led to greater numbers of traffic incidents and subsequent growth of non-recurrent congestion. Existing incident detection techniques are limited to the use of sensors in the transportation network. In this paper, we analyze the potential of Twitter for supporting real-time incident detection in the United Kingdom (UK). We present a methodology for retrieving, processing, and classifying public tweets by combining Natural Language Processing (NLP) techniques with a Support Vector Machine algorithm (SVM) for text classification. Our approach can detect traffic related tweets with an accuracy of 88.27%.Published versio
Marijuana use among young people in an era of policy change: what does recent evidence tell us?
R25 DA030310 - National Institute on Drug Abus
A Note on Einstein Gravity on AdS and Boundary Conformal Field Theory
We find a simple relation between the first subleading terms in the
asymptotic expansion of the metric field in AdS, obeying the Brown-Henneaux
boundary conditions, and the stress tensor of the underlying Liouville theory
on the boundary. We can also provide an more explicit relation between the bulk
metric and the boundary conformal field theory when it is described in terms of
a free field with a background charge.Comment: LateX file, 10 page
Effect of ancilla's structure on quantum error correction using the 7-qubit Calderbank-Shor-Steane code
In this work we discuss the ability of different types of ancillas to control
the decoherence of a qubit interacting with an environment. The error is
introduced into the numerical simulation via a depolarizing isotropic channel.
After the correction we calculate the fidelity as a quality criterion for the
qubit recovered. We observe that a recovery method with a three-qubit ancilla
provides reasonable good results bearing in mind its economy. If we want to go
further, we have to use fault-tolerant ancillas with a high degree of
parallelism, even if this condition implies introducing new ancilla
verification qubits.Comment: 24 pages, 10 Figures included. Accepted in Phys. Rev. A 200
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