Fast remote but not extreme quantiles with multiple factors. Applications to Solvency II and Enterprise Risk Management

For operational purposes, in Enterprise Risk Management or in insurance for example, it may be important to estimate remote (but not extreme) quantiles of some function ƒ of some random vector. The call to ƒ may be time- and resource-consuming so that one aims at reducing as much as possible the number of calls to ƒ. In this paper, we propose some ways to address this problem of general interest. We then numerically analyze the performance of the method on insurance and Enterprise Risk Management real-world case studies.

Pas de quartier pour le sexe ?

Cet article vise à examiner différents espaces de la drague et des rencontres sexuelles, et la manière qu'ont eu les sciences sociales de laisser certaines formes de désir sexuel dans l'ombre en particulier du point de vue du genre et de l’orientation sexuelle. Fondé sur trois enquêtes sur les terrains de la prostitution, des lieux de drague entre hommes et de la sociabilité sexuelle entre hommes et femmes, il aborde à la fois la question du contrôle auquel les territoires sexuels semblent soumis à première vue et, en même temps, s’efforce de dégager les conditions qui rendent les pratiques tantôt spectaculaires, tantôt invisibles, aussi bien dans des espaces publics réels que « prises » dans l’opinion contemporaine, productions scientifiques comprises.This article proposes to analyse different spaces dedicated to sexual cruising and encounters, and the way social sciences have sometimes neglected certain forms of sexual desire, in particular regarding gender and sexual identity. Grounded on three fieldwork surveys on sex work, men-to-men cruising for sex, and men and women sexual sociability venues, it outlines the way sexual territories seem to be under control at first sight, and tries to show that sexual conducts alternatively appear spectacular or remain invisible, both in material public spaces and in contemporary debates, including academic research

Prospectives

Tiré de: Prospectives, vol. 16, no 4, déc. 1980Titre de l'écran-titre (visionné le 24 janv. 2013

Improving local wind estimation for the automated control of blinds

Blinds are usually installed on building façade to improve the visual and thermal comfort of the oc-cupants. They are now often linked to an automat-ed system that helps control the glare and decrease overheating. These automated systems are linked to a weather station that is located on top of the buildings on which they are installed. In the cur-rent study, we show that the use of such stations does not provide accurate and reliable information to the control algorithm. It is proposed to couple a model that can calculate wind speed and direction in an urban canopy to the control algorithm. The model is compared to data from an experimental setup on the EPFL campus, Switzerland. We demonstrate that there is very good agreement between the models and the data that have been collected. Furthermore, a new control algorithm was proposed in order to improve the response of the system during strong gusts and to prevent er-ratic behaviour of the automated system

Modeling the phase equilibria of refrigerant fluids with the COSMO-SAC and COSMO-RS approaches. Application to process simulation

International audienceOn account of the constraints imposed by the European and International legislations, the refrigerant industry must constantly find alternative refrigerant fluids that have lower impacts on the global warming of Earth and Ozone layer. Working with refrigerant blends is often preferable to pure component fluids for energy saving and flexibility of operation. In order to select the optimal mixture composition for the design and operation of a refrigeration process, it is necessary to know the phase diagram and thermodynamic properties of mixtures. Vapor-liquid equilibria (VLE) and the location of azeotropes must be accurately known. In this work three different thermodynamic models based on the COSMO approach have been used to predict the phase equilibria of mixtures of refrigerant molecules: the COSMO-RS model developed by Klamt and co workers [1, 2], the 2002 version of COSMO-SAC model [3], and the COSMO-SAC-dsp model [4] that includes a dispersion term. The vapor-liquid equilibria can be reasonably well predicted by the COSMO-RS model, however bad predictions are obtained with COSMO-SAC 2002. In particular, the COSMO-SAC model is unable to predict the azeotropic behavior observed in mixtures of alkanes and fluorinated molecules. By adjusting some universal parameters, it is possible to obtain reasonable predictions with the COSMO-SAC dsp model

Measurement of the impact of buildings on meteorological variables

A meteorological tower was installed on the EPFL campus in a semi-urban environment for the high frequency monitoring of the micro-climate. This project was done in the larger framework of the measurement of the meteorological profiles and also a quantification of the energy consumption and the outdoor human comfort. A long-term monitoring of various meteorological variables like wind speed, air temperature, turbulence, humidity is realized by the use of 3D sonic anemometers, surface temperature sensor and a meteorological station so as to analyse the micro-climate in an urban context. The preliminary results from the experimental setup confirms that the wind speed is considerably modified in the urban canopy. We show that the decrease in the wind speed will have a significant effect on the heat convection coefficient. Furthermore, we demonstrate that it is possible to reconstruct the air temperature along the vertical axis with a correction using the data from the meteorological station. In the near future, a net radiometer will be installed to analyse the influence of the incoming and outgoing radiation in the urban setup on the energy balance of the district

Continuous or interrupted pledgeted suture technique in stented bioprosthetic aortic valve replacement:a comparison of in-hospital outcomes

Background: There is ambiguity in the literature regarding the continuous suture technique (CST) for aortic valve replacement (AVR). At our center, there has been a gradual shift towards CST over the interrupted pledgeted technique (IPT). This study aims at comparing outcomes for both techniques. Methods: We performed a retrospective analysis of a single-center study of patients undergoing AVR between January 2011 and July 2020. Patients were divided into two groups: Continuous suture technique and interrupted pledget-reinforced sutures. The pre-operative and In-hospital clinical characteristics and echocardiographic hemodynamics (i.e. transvalvular gradients and paravalvular leakage) were compared between CST and IPT. Results: We compared 791 patients with CST to 568 patients with IPT (median age: 73 and 74 years, respectively, p = 0.02). In CST there were 35% concomitant procedure vs. 31% in IPT (p = 0.16). Early mortality was 3.2% in CST versus 4.8% in IPT (p = 0.15), and a second cross-clamp due to a paravalvular-leak in 0.5% vs. 1.2%, respectively (p = 0.22). The CST was not associated with new-onset conduction-blocks mandating pacemaker implants(OR 1.07, 95% CI 0.54–2.14; P = 0.85). The postoperative gradients on echocardiography were lower in CST compared to IPT, especially in smaller annuli (peak gradients: 15.7mmHg vs. 20.5mmHg, in valve size &lt; 23 mm, p &lt; 0.001). Conclusions: The continuous suture technique was associated with lower postoperative gradients and shorter cross-clamp time compared to interrupted pledgeted technique. Differences in paravalvular leaks were non-significant, although slightly less in the continuous suture technique. There were no further differences in valve-related complications. Hence, continues suture technique is safe, with better hemodynamics compared to the interrupted pledgeted technique. This may be of clinical importance, especially in smaller size annular size.</p

Assessment of Circadian Weighted Radiance Distribution Using a Camera-Like Light Sensor

Suboptimal light distribution in a room can cause visual discomfort and glare. Next to rods and cones, perception of light is also governed by a third class of photoreceptors, important for circadian rhythm regulation and non-visual functions such as alertness, mood and hormonal secretion. These receptors show greatest sensitivity in the blue part of the visible light spectrum. In order to assess light distribution with respect to non-visual sensitivity functions, we aimed at validating a new device to create light distribution maps with a circadian weighted radiance (Lec) which accounts for this difference in sensitivity. We utilized a camera-like light sensor (CLLS) to assess the distribution of Lec. For this purpose, we equipped the device with customized filters to adapt the camera’s spectral sensitivity to circadian sensitivity, similarly, as we had previously reported for the photometric calibration with the same device [1]. After spectral calibration and circadian weighted radiance calibration, we validated the CLLS in real scenes. The results showed that circadian luminance maps of a room can be efficiently assessed in a very short time (i.e. within 100 ms) under electric lighting as well as under daylighting conditions. We also used the CLLS to compare the Lec values between two rooms, equipped with different daylighting systems such as LightLouverTM and standard venetian blinds. Our results showed different dynamics of luminance and Lec in the course of the day with highest values at noon. We also found higher luminance and Lec values in the test room with the venetian blinds, when compared to the room equipped with LightLouversTM. Taken together, the validation of circadian luminance maps under real dynamic lighting conditions offers new possibilities to integrate the CLLS into advanced (day-) light sensors systems. This would allow to instantly adapting ambient lighting conditions with respect to tailored biological user needs