165 research outputs found
Anomalous Nernst and Thermal Hall Effects in Tilted Weyl Semimetals
We study the anomalous Nernst and thermal Hall effects in a linearized
low-energy model of a tilted Weyl semimetal, with two Weyl nodes separated in
momentum space. For inversion symmetric tilt, we give analytic expressions in
two opposite limits: for a small tilt, corresponding to a type-I Weyl
semimetal, the Nernst conductivity is finite and independent of the Fermi
level, while for a large tilt, corresponding to a type-II Weyl semimetal, it
acquires a contribution depending logarithmically on the Fermi energy. This
result is in a sharp contrast to the nontilted case, where the Nernst response
is known to be zero in the linear model. The thermal Hall conductivity
similarly acquires Fermi surface contributions, which add to the Fermi level
independent, zero tilt result, and is suppressed as one over the tilt parameter
at half filling in the Type-II phase. In the case of inversion breaking tilt,
with the tilting vector of equal modulus in the two Weyl cones, all Fermi
surface contributions to both anomalous responses cancel out, resulting in zero
Nernst conductivity. We discuss two possible experimental setups, representing
open and closed thermoelectric circuits
Chirality-dependent transmission of spin waves through domain walls
Spin-wave technology (magnonics) has the potential to further reduce the size
and energy consumption of information processing devices. In the submicrometer
regime (exchange spin waves), topological defects such as domain walls may
constitute active elements to manipulate spin waves and perform logic
operations. We predict that spin waves that pass through a domain wall in an
ultrathin perpendicular-anisotropy film experience a phase shift that depends
on the orientation of the domain wall (chirality). The effect, which is absent
in bulk materials, originates from the interfacial Dzyaloshinskii-Moriya
interaction and can be interpreted as a geometric phase. We demonstrate
analytically and by means of micromagnetic simulations that the phase shift is
strong enough to switch between constructive and destructive interference. The
two chirality states of the domain wall may serve as a memory bit or spin-wave
switch in magnonic devices.Comment: 11 pages, 10 figures (incl. supp. mat.); Phys. Rev. Lett. (accepted
ASLP-MULAN: Audio speech and language processing for multimedia analytics
Our intention is generating the right mixture of audio, speech and language technologies with big data ones. Some audio, speech and language automatic technologies are available or gaining enough degree of maturity as to be able to help to this objective: automatic speech transcription, query by spoken example, spoken information retrieval, natural language processing, unstructured multimedia contents transcription and description, multimedia files summarization, spoken emotion detection and sentiment analysis, speech and text understanding, etc. They seem to be worthwhile to be joined and put at work on automatically captured data streams coming from several sources of information like YouTube, Facebook, Twitter, online newspapers, web search engines, etc. to automatically generate reports that include both scientific based scores and subjective but relevant summarized statements on the tendency analysis and the perceived satisfaction of a product, a company or another entity by the general population
AMIC: Affective multimedia analytics with inclusive and natural communication
Traditionally, textual content has been the main source of information extraction and indexing, and other technologies that are capable of extracting information from the audio and video of multimedia documents have joined later. Other major axis of analysis is the emotional and affective aspect intrinsic in human communication. This information of emotions, stances, preferences, figurative language, irony, sarcasm, etc. is fundamental and irreplaceable for a complete understanding of the content in conversations, speeches, debates, discussions, etc. The objective of this project is focused on advancing, developing and improving speech and language technologies as well as image and video technologies in the analysis of multimedia content adding to this analysis the extraction of affective-emotional information. As additional steps forward, we will advance in the methodologies and ways for presenting the information to the user, working on technologies for language simplification, automatic reports and summary generation, emotional speech synthesis and natural and inclusive interaction
Inclusión de indicadores sociales en el análisis de requerimientos energéticos : El caso de la provincia de Salta
Pese a que desde hace casi veinte años, y como parte de la etapa de privatización del suministro eléctrico disperso, existen en el NOA programas de electrificación rural, el objetivo central de los mismos solo se cumplió parcialmente. En esta región habitan casi cinco millones de habitantes y representan más del diez por ciento de la población total del país. En la región, más del ochenta y cinco por ciento de la población posee redes convencionales de energía, pero el NBI promedio es de algo menos del 28%. Desde el programa PERMER y otros, se asignan recursos para instalar electricidad con paneles fotovoltaicos, y con mini redes de diferentes tipos, en un esfuerzo notable de gobiernos y empresas. Es de destacar, que no todos los sitios habitados podrán gozar del “beneficio”, dado que las solicitudes son numerosas. En otro orden de cosas, la radiación solar promedio en la región es muy adecuada para su aprovechamiento, por lo que con ella se puede paliar la situación pese a lo elevado de la inversión inicial. Se propone un mecanismo para poder seleccionar objetivamente las localidades que puede servir de herramienta para la toma de decisiones, en el marco de un programa de aplicación regional. Conviene aclarar que existen otros, igualmente valiosos.There are almost twenty years in the NOA rural electrification programs, as part of a process of privatization of companies. The central objective of these only partially fulfilled. This region is home to nearly five million people, representing more than ten percent of the total population. In the region, more than eighty-five percent of the population owns conventional 08.09 energy networks, but the average NBI is just under 28%. Since the program PERMER and others, resources are allocated to electrifies with photovoltaic panels, and mini networks of different types, in a remarkable effort of governments and businesses.
It is noteworthy that not all inhabited sites may enjoy the "benefit", given that applications are numerous. In another vein, the average solar radiation in the region is very good for its use, so that it can alleviate the situation despite the high level of initial investment. A mechanism is proposed to objectively select locations that can serve as a tool for decision making in the context of a regional implementation program. It should be clear that there are other, equally valuable.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
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