421 research outputs found
Degenerate parametric oscillation in quantum membrane optomechanics
The promise of innovative applications has triggered the development of many
modern technologies capable of exploiting quantum effects. But in addition to
future applications, such quantum technologies have already provided us with
the possibility of accessing quantum-mechanical scenarios that seemed
unreachable just a few decades ago. With this spirit, in this work we show that
modern optomechanical setups are mature enough to implement one of the most
elusive models in the field of open system dynamics: degenerate parametric
oscillation. The possibility of implementing it in nonlinear optical resonators
was the main motivation for introducing such model in the eighties, which
rapidly became a paradigm for the study of dissipative phase transitions whose
corresponding spontaneously broken symmetry is discrete. However, it was found
that the intrinsic multimode nature of optical cavities makes it impossible to
experimentally study the model all the way through its phase transition. In
contrast, here we show that this long-awaited model can be implemented in the
motion of a mechanical object dispersively coupled to the light contained in a
cavity, when the latter is properly driven with multi-chromatic laser light. We
focus on membranes as the mechanical element, showing that the main signatures
of the degenerate parametric oscillation model can be studied in
state-of-the-art setups, thus opening the possibility of studying spontaneous
symmetry breaking and enhanced metrology in one of the cleanest dissipative
phase transitions.Comment: We welcome comments, suggestions, and (constructive) criticis
Robust symmetric multiplication for programmable analog VLSI array processing
This paper presents an electrically programmable analog multiplier. The circuit performs the multiplication between an input variable and an electrically selectable scaling factor. The multiplier is divided in several blocks: a linearized transconductor, binary weighted current mirrors and a differential to single-ended current adder. This paper shows the advantages introduced using a linearized OTA-based multiplier. The circuit presented renders higher linearity and symmetry in the output current than a previously reported single-transistor multiplier. Its inclusion in an array processor based on CNN allows for a more accurate implementation of the processing model and a more robust weight distribution scheme than those found in previous designs.Office of Naval Research (USA) N-00014- 02-1-0884Ministerio de Ciencia y Tecnología TIC2003-09817-C02-0
A Focal-Plane Image Processor for Low Power Adaptive Capture and Analysis of the Visual Stimulus
Portable applications of artificial vision are limited by the fact that conventional processing schemes fail to meet the specifications under a tight power budget. A bio-inspired approach, based in the goal-directed organization of sensory organs found in nature, has been employed to implement a focal-plane image processor for low power vision applications. The prototype contains a multi-layered CNN structure concurrent with 32times32 photosensors with locally programmable integration time for adaptive image capture with on-chip local and global adaptation mechanisms. A more robust and linear multiplier block has been employed to reduce irregular analog wave propagation ought to asymmetric synapses. The predicted computing power per power consumption, 142MOPS/mW, is orders of magnitude above what rendered by conventional architectures
El derecho fundamental a no sufrir discriminación racial
El racismo y la discriminación racial son fenómenos muy extendidos en las sociedades actuales que, por su peculiar configuración y las nuevas formas bajo las que se manifiestan, requieren de respuestas jurídicas adecuadas. Existe un marco normativo e institucional en los niveles internacional y europeo que, sin embargo, no ha encontrado verdadera acogida en el ordenamiento jurídico interno. Para garantizar en España el derecho fundamental a no sufrir discriminación racial es imprescindible asumir plenamente nuestros compromisos y construir un sistema estatal coherente e integrado que se aplique de manera efectiva.Grado en Derech
Hacia políticas públicas de vivienda inclusivas y diversas: derecho a la vivienda y derecho a la igualdad y no discriminación
Este análisis se enmarca temporalmente en mi estancia de investigación en TransJus, entre marzo y abril de 2019, donde tuve la ocasión de trabajar estrechamente con el profesor Juli Ponce Solé y con los demás miembros de este centro de investigación dedicados a problemáticas relativas a la vivienda. A todos ellos les agradezco la afectuosa bienvenida y los enriquecedores intercambios, comentarios y reflexiones surgidos a raíz de mi estancia. Antes de comenzar con el desarrollo de este trabajo, quiero expresar mi reconocimiento
poniendo en valor la labor de aplicación práctica de políticas en materia de vivienda desarrollada durante los últimos años en Barcelona, en el marco de la legislación catalana sobre el derecho a la vivienda, que dan forma a muchas de las reflexiones que expongo a continuación (Falagán, 2019; Observatorio DESC & Instituto de Investigación TransJus, 2018)
La décision du comité des droits économiques, sociaux et culturels dans l¿affaire lópez albán c. Espagne : La nécessité d¿un contrôle de proportionnalité dans les procédures d¿expulsion locative
On 30 October 2019, the UN Committee on Economic, Social and Cultural Rights made public its decision in the case of López Albán v. Spain. The case concerned a single mother with six children occupying a vacant apartment owned by a financial entity out of necessity, after being excluded from the possibility of obtaining public housing. The family was eventually evicted without adequate alternative accommodation. The Committee found that this eviction violated the right to adequate housing enshrined in the International Covenant on Economic, Social and Cultural Rights. This article summarises the case, provides a contextual analysis in light of recent developments, makes a comparison with the case law of the European Court of Human Rights, and notes some legal avenues the Committee could explore in future decisionsLe Comité des droits économiques, sociaux et culturels a publié sa décision dans l¿affaire López Albán c. Espagne le 30 octobre 2019. Il s¿agit d¿une affaire où une mère célibataire avec six enfants occupait un appartement vide propriété d¿un établissement financier par nécessité, après avoir été exclue de la possibilité d¿obtenir un logement public. La famille fût finalement expulsée, sans une alternative de relogement adéquate. Le Comité a trouvé que cette expulsion a constitué une violation du Pacte international relatif aux droits économiques, sociaux et culturels. Cet article présente un sommaire de l¿affaire, offre une analyse contextuelle à la lumière de certains développements récents, fait une comparaison avec la jurisprudence de la Cour européenne des droits de l¿homme, et remarque quelques avenues juridiques que le Comité pourrait explorer dans ses décisions à venirUniversidad Pablo de Olavid
CESCR decisions on the right to housing in Spain. Domestic case law and legislative responses
Este artículo examina los pronunciamientos del Comité de Derechos Económicos, Sociales y Culturales de Naciones Unidas (Comité DESC) sobre el derecho a la vivienda relativos a España y adoptados en el período 2017¿2018, en particular en cuanto a los desalojos forzosos. Destaca, por su importancia y novedad, el dictamen del Comité DESC en el caso Ben Djazia et al. Seguidamente, se exponen y analizan las novedades jurisprudenciales y legislativas estatales en conexión con estos pronunciamientos, con el fin de evaluar si estas respuestas siguen la línea marcada por el Comité DESC e incorporan las garantías que rodean al derecho a una vivienda adecuada en Derecho internacional y europeo de los derechos humanosThis article examines the decisions taken by the UN Committee on Economic, Social and Cultural Rights (CESCR) regarding the right to housing in Spain between 2017 and 2018, in particular concerning forced evictions. The Committee¿s views in the case of Ben Djazia et al. are especially noteworthy.
Domestic case law and legislative developments are then presented and analysed, in order to evaluate whether these responses are aligned with the CESCR¿s interpretation and whether they incorporate the guarantees surrounding the right to adequate housing in international and European human rights law.Universidad Pablo de Olavid
A low-area reference-free power supply sensor
Power supply unpredictable uctuations jeopardize the functioning of several types of current electronic systems. This work presents a power supply sensor based on a voltage divider followed by buffer-comparator cells employing just MOSFET transistors and provides a digital output. The divider outputs are designed to change more slowly than the thresholds of the comparators, in this way the sensor is able to detect voltage droops. The sensor is implemented in a 65nm technology node occupying an area of 2700?m2 and displaying a power consumption of 50?W. It is designed to work with no voltage reference and with no clock and aiming to obtain a fast response
Smart-Pixel Cellular Neural Networks in Analog Current-Mode CMOS Technology
This paper presents a systematic approach to design CMOS chips with concurrent picture acquisition and processing capabilities. These chips consist of regular arrangements of elementary units, called smart pixels. Light detection is made with vertical CMOS-BJT’s connected in a Darlington structure. Pixel smartness is achieved by exploiting the Cellular Neural Network paradigm [1], [2], incorporating at each pixel location an analog computing cell which interacts with those of nearby pixels. We propose a current-mode implementation technique and give measurements from two 16 x 16 prototypes in a single-poly double-metal CMOS n-well 1.6-µm technology. In addition to the sensory and processing circuitry, both chips incorporate light-adaptation circuitry for automatic contrast adjustment. They obtain smart-pixel densities up to 89 units/mm2, with a power consumption down to 105 µW/unit and image processing times below 2 µs
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