10,399 research outputs found
Learning Economic Parameters from Revealed Preferences
A recent line of work, starting with Beigman and Vohra (2006) and
Zadimoghaddam and Roth (2012), has addressed the problem of {\em learning} a
utility function from revealed preference data. The goal here is to make use of
past data describing the purchases of a utility maximizing agent when faced
with certain prices and budget constraints in order to produce a hypothesis
function that can accurately forecast the {\em future} behavior of the agent.
In this work we advance this line of work by providing sample complexity
guarantees and efficient algorithms for a number of important classes. By
drawing a connection to recent advances in multi-class learning, we provide a
computationally efficient algorithm with tight sample complexity guarantees
( for the case of goods) for learning linear utility
functions under a linear price model. This solves an open question in
Zadimoghaddam and Roth (2012). Our technique yields numerous generalizations
including the ability to learn other well-studied classes of utility functions,
to deal with a misspecified model, and with non-linear prices
The first INTEGRAL-OMC catalogue of optically variable sources
The Optical Monitoring Camera (OMC) onboard INTEGRAL provides photometry in
the Johnson V-band. With an aperture of 50 mm and a field of view of 5deg x
5deg, OMC is able to detect optical sources brighter than V~18, from a
previously selected list of potential targets of interest. After more than nine
years of observations, the OMC database contains light curves for more than
70000 sources (with more than 50 photometric points each). The objectives of
this work have been to characterize the potential variability of the objects
monitored by OMC, to identify periodic sources and to compute their periods,
taking advantage of the stability and long monitoring time of the OMC. To
detect potential variability, we have performed a chi-squared test, finding
5263 variable sources out of an initial sample of 6071 objects with good
photometric quality and more than 300 data points each. We have studied the
periodicity of these sources using a method based on the phase dispersion
minimization technique, optimized to handle light curves with very different
shapes.In this first catalogue of variable sources observed by OMC, we provide
for each object the median of the visual magnitude, the magnitude at maximum
and minimum brightness in the light curve during the window of observations,
the period, when found, as well as the complete intrinsic and period-folded
light curves, together with some additional ancillary data.Comment: Accepted by Astronomy & Astrophysics; 13 pages, 16 figures. Figures'
resolution has been degraded to fit astro-ph constraint
Regulating altruistic agents
Altruism or `regard for others' can encourage self-restraint among generators of negative externalities, thereby mitigating the externality problem. We explore how introducing impure altruism into standard regulatory settings alters regulatory prescriptions. We show that the optimal calibration of both quantitative controls and externality taxes are affected. It also leads to surprising results on the comparative performance of instruments. Under quantity-based regulation welfare is increasing in the propensity for altruism in the population; under price-based regulation the relationship is non-monotonic. Price-based regulation is preferred when the population is either predominantly altruistic or predominantly selfish, quantity-based regulation for cases in between
Force measurements with optical tweezers inside living cells
The force exerted by optical tweezers can be measured by tracking the momentum changes of the trapping beam, a method which is more general and powerful than traditional calibration techniques as it is based on first principles, but which has not been brought to its full potential yet, probably due to practical difficulties when combined with high-NA optical traps, such as the necessity to capture a large fraction of the scattered light. We show that it is possible to measure forces on arbitrary biological objects inside cells without an in situ calibration, using this approach. The instrument can be calibrated by measuring three scaling parameters that are exclusively determined by the design of the system, thus obtaining a conversion factor from volts to piconewtons that is theoretically independent of the physical properties of the sample and its environment. We prove that this factor keeps valid inside cells as it shows good agreement with other calibration methods developed in recent years for viscoelastic media. Finally, we apply the method to measuring the stall forces of kinesin and dynein in living A549 cells.Publisher PD
An Innovative Methodology to Optimize Aerospace Eco-efficiency Assembly Processes
Sustainability and eco-efficiency have been researched in multiple
scientific papers since the last years. However the literature is not so abundant
when applying those concepts to industrial assembly processes. This paper
presents an innovate methodology to optimize aerospace assembly processes.
Authors propose the introduction of a new element, the eco-efficiency, along
with the traditional criteria, cost and time, currently used for optimization. Using
a large Aero-Structure as an industrial case of study, the methodology analyzes
the eco-efficiency of an assembly process in connection with a Life Cycle
Assessment (LCA) to compute the environmental impact. Results are shown in a
dashboard along with the relevant Key Process Indicator (KPI) to help the
engineers to select the best assembly processEuropean Union (UE). H2020 DILECO 785367European Union H2020-EU.3.4.5.4-IT
Sobre el contraste de pareceres: la tecnocracia franquista ante las nuevas fórmulas de representación política
La promoción de las asociaciones políticas
vino condicionada por el articulado de la Ley
Orgánica del Estado aprobada en 1967 como culminación del proceso institucional del franquismo.
La redefinición del Movimiento como comunión de los españoles en los Principios Fundamentales de 1958, suponía el triunfo de la concepción ideológica tradicionalista asumida por el equipo de la Presidencia,
frente a las posturas estatistas representadas por la Secretaría General del Movimiento. Esta dicotomía de pareceres en la definición institucional, venía animada tanto por la diversidad de tendencias en el seno del Régimen como por las repercusiones
derivadas de la esfera internacional. En cualquier caso, la discusión de planteamientos sobre la participación política estaría condicionada por la rigidez
intrínseca del sistema.------------------The promotion of the political associations was determined by the articles of the Organic
Law of the State, approved in 1967 as the culmination of the institutional process of Franco’s regime.
The redefinition of the Movement as the communion of the spaniards in the Fundamental Principles of 1958, supposed the triumph of the ideological traditionalist conception assumed by the Presidency’s
team, over the totalitarian positions represented by the General Secretariat of the Movement. This dichotomy of opinions in the institutional definition, was encouraged by the diversity of trends inside the Regime as well as the repercussions derived from the international sphere. Nevertheless, the political participation discussion would be determined by the system’s own inflexibility
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