Infoscience - École polytechnique fédérale de Lausanne

    Lausanne, chapitres II ; III, une séquence architecturale

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    Lieu: Lausanne 2020 ; Site: Flon-Sevelin-Sebeillon-Malley-Renens ; Projet: parcours architectural ; Programme: plates-formes, couverts, passerelles, artefacts architecturaux ... ; Stratégie: le montage cinématographique ; Le projet raconte l'histoire d'un parcours effectué à pied à travers une séquence de sites tous différents les uns des autres dans leur état, usage, atmosphère, condition urbanistique et caractère architectural. Un parcours vécu à travers une séquence d'interventions prenant place dans les divers chapitres de l'histoire. Inscrit dans le contexte futur d'un Ouest-lausannois développé et urbanisé, le projet s'attarde sur des questions de mémoire du lieu et d'espaces publics. L'outil du film fut utilisé pour investiguer le lieu, en capturer les acteurs et valoriser l'héritage. En spéculant sur les rapports entre cinéma et architecture, la stratégie du montage cinématographique est utilisée pour scénariser les divers interventions architecturales, introduites tels des artefacts mettant en scène les programmes et leurs protagonistes, pour la plupart, déjà présents sur le site

    La grande traversée de la rade de Genève (GE)

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    Genève est la plus petite des grandes capitales grâce au nombre d’institutions internationales qu’elle abrite, ainsi que par son positionnement sur la scène mondiale. La qualifier de capitale l’élève au rang des grandes villes du monde. Lorsque l’on regarde Paris, Washington ou Berlin, des grandes voies de communication ceinturent ces villes et les améliorent. Ceci génère des centres urbains clairs et un bon système de mobilité. En ajoutant la grande traversée de la rade à Genève, le schéma typologique de la ville se clarifie. Les projections des charges de trafic après la réalisation de la grande traversée de la rade de Genève démontrent son efficacité. En effet, la traversée permet de délester non seulement l’autoroute de contournement, mais aussi de décongestionner le centre-ville, ce qui peut véritablement contribuer à augmenter la qualité de vie des habitants. Le projet proposé est la grande traversée, fonctionnant en symbiose avec un système de voies rapides immergées dans la rade, desservant les quais ponctuellement. Le nouveau potentiel pourrait créer de véritables espaces publics au bord de l’eau. Ce système de tunnel se transforme en pont suspendu lors de la grande traversée, afin de conférer à Genève une image urbaine forte. Les deux piles du pont sont des immeubles, pouvant répondre aux divers besoins programmatiques que la ville nécessite. Le tablier, constitué de bois et de matériaux composites, vole au-dessus de l’eau

    Rencontre verticale: toit sur rue, rue sur toit. Superposition, densification et mixité aux Grottes, Genève

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    Le contexte actuel de densification des villes pousse à la recherche de nouvelles formes urbanistiques, architecturales et sociales. A Genève bourgeonnent des surélévations, opérations ponctuelles, constructions spontanées d'un nouveau niveau urbain. Le projet vise à penser la surélévation comme une opération d'ensemble. La superposition d'un nouvel étage à la ville qui ne renierait pas le sol, mais lui offrirait une extension spatiale, enrichissant l'existant par le nouveau. Le quartier des Grottes à Genève, fort de son histoire alternative et appropriative est le terreau de cette mutation urbanistique. Le quartier se présente en son sein comme une petite urbanité, protégée par des fronts marqués de la grande urbanité genevoise. L'extension de la gare Cornavin rapprochera ces deux mondes. Le projet réagit à cette proximité à venir. Deux impulsions naissent dans le tissu hétérogène du quartier et mettent en tension l'espace public de la rue des Grottes. Elles proposent en deux places une escalade de son air, de ses programmes et de ses gens vers un nouvel étage de relation, de rencontre, de vie en communauté. De cette mutation urbanistique naît un hybride architectural qui s'étend de bâtiment à bâtiment, d'îlot à îlot, et de la toiture à la rue. Entre surélévation et franchissement, il tisse des liens autant physiques que sociaux et climatiques. Un monde particulier, un “vivre ensemble” qui lie l'habitat au programme public par l'atelier, le toit au sol par l'espace social

    Behavioral high-frequency modeling of electrical motors

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    Reliable simulations of electromagnetic interference in motor drive power electronic systems ask for accurate high-frequency motor models. A methodology for creating frequency dependent behavioral circuit models of ac electrical motors is presented in this paper. It is based on the rational function fitting of measured motor network parameters. Stable, causal, and passive equivalent circuits are obtained and their accuracy verified by comparing the simulation results with frequency domain common- and differential-mode measurements

    Towards a Disambiguation Canvas

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    We present Disambiguation canvas, a technique for selection by progressive refinement using a mobile device and consisting of two steps. During the first, the user defines a subset of objects through the orientation sensors of the device and a volume-casting pointing technique. The subsequent step consists of the disambiguation of the desired target among the previously-defined subset of objects, and is accomplished using the mobile device touchscreen. By relying on the touchscreen for the last step the user can disambiguate among hundreds of objects at once, previous progressive refinement techniques do not scale as well as ours. Disambiguation canvas is mainly developed for easy, accurate and fast selection of small objects, or objects inside cluttered virtual environments. User tests show that our technique performs faster than ray-casting for targets with approximate to 0 : 53 degrees of angular size, and is also much more accurate for all the tested target sizes

    Enhancing the Performances of H-plane SIW Horn Antennas

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    The performances of SIW horns antennas diminish significantly when the substrate thickness is much smaller than the free space wavelength lambda(0). Specifically, the mismatch between the antenna aperture and the air yields to unwanted back radiation and poor matching. This paper presents a fully printed structure etched after the horn aperture to simultaneously solve these two problems. Models based on transmission line and array theory have been developed to analyse and synthesize this new type of structure. They provide simple design rules to characterize the SIW horn geometry and to reasonably predict its electromagnetic performances. In addition, the horn profile is further optimized by reducing its dimensions needed for a given directivity. The presented concepts are verified by manufacturing a prototype in a substrate thinner than lambda(0)/10 working between 14.2-15.4 GHz. Its excellent performances (|S-11| 15 dB) together with simple and low-cost construction opens the door to the use of SIW horns in many other applications

    Kinetics Of Desorption Of Water, Ethanol, Ethyl Acetate, And Toluene From A Montmorillonite

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    Desorption processes of low-molecular-weight compounds from the surface of smectites into the gas phase determine a number of processes, e.g. those involved in drug delivery and the release of herbicides. The desorption has not been investigated thoroughly and is not well understood. The present study was undertaken in order to understand better the factors influencing these desorption mechanisms. Starting with a very pure standard (Na+-rich) montmorillonite (Kunipia-F), which was exchanged against cations with different hydration properties (Ca2+, Li+, phenyltrimethylammonium, hexyltrimethylammonium), the experiments explored the rate of desorption of volatiles with different chemical functionalities (water, ethanol, ethyl acetate, and toluene). The desorption was monitored by thermogravimetry and differential scanning calorimetry under isothermal conditions, and by ramping the temperature at a constant rate. The experiments were compared with numerical calculations based on finite-element methods and with analytical models. These data point to a two-step mechanism where the desorption follows the curve of the equilibrium desorption isotherms of those molecules on the montmorillonite. The bulk-like volatiles (i.e. volatiles with release kinetics close to that of the bulk liquids) were desorbed in a first step. With a decrease in the degree of coverage of the volatile on the montmorillonite, the desorption was increasingly dominated by the strength of interaction between the volatile and the interlayer cations of the montmorillonite

    Assessing the potential of using telecommunication microwave links in urban drainage modelling

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    The ability to predict the runoff response of an urban catchment to rainfall is crucial for managing drainage systems effectively and controlling discharges from urban areas. In this paper we assess the potential of commercial microwave links (MWL) to capture the spatio-temporal rainfall dynamics and thus improve urban rainfall-runoff modelling. Specifically, we perform numerical experiments with virtual rainfall fields and compare the results of MWL rainfall reconstructions to those of rain gauge (RG) observations. In a case study, we are able to show that MWL networks in urban areas are sufficiently dense to provide good information on spatio-temporal rainfall variability and can thus considerably improve pipe flow prediction, even in small subcatchments. In addition, the better spatial coverage also improves the control of discharges from urban areas. This is especially beneficial for heavy rainfall, which usually has a high spatial variability that cannot be accurately captured by RG point measurements

    From big smartphone data to worldwide research: The Mobile Data Challenge

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    This paper presents an overview of the Mobile Data Challenge (MDC), a large-scale research initiative aimed at generating innovations around smartphone-based research, as well as community-based evaluation of mobile data analysis methodologies. First, we review the Lausanne Data Collection Campaign (LDCC), an initiative to collect unique longitudinal smartphone dataset for the MDC. Then, we introduce the Open and Dedicated Tracks of the MDC, describe the specific datasets used in each of them, discuss the key design and implementation aspects introduced in order to generate privacy-preserving and scientifically relevant mobile data resources for wider use by the research community, and summarize the main research trends found among the 100+ challenge submissions. We finalize by discussing the main lessons learned from the participation of several hundred researchers worldwide in the MDC Tracks

    Achieving and sustaining advanced scenarios in ITER modelled by CRONOS and DINA-CH

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    The heating and current drive characteristics for accessing advanced scenarios in ITER, close to those obtained in present-day experiments, are analysed together with the plasma performance using the prescribed-boundary CRONOS suites of codes. For the hybrid scenario, a sensitivity analysis shows the sensitivity to the parameter range which leads to an appropriate control of the safety factor and pressure profiles. A steady-state regime with no internal transport barrier is obtained as a natural extension of the hybrid regime. These prescribed-boundary scenario developments are used as an initial step for a complete free-boundary simulation carried out with the DINA-CH code coupled to CRONOS, which once again underlines how sensitive the ITER advanced scenarios are to small plasma geometry changes. Both scenarios were achieved within the technical limits of ITER, specifically the poloidal field coil currents, voltages, forces and fields
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