École Nationale Supérieure d'Architecture de Grenoble

The exponential increase of mobile data traffic requires disrupting approaches for the realization of future 5G systems. In this article, we overview the technologies that will pave the way for a novel cellular architecture that integrates high-data-rate access and backhaul networks based on millimeter-wave frequencies (57-66, 71-76, and 81-86 GHz). We evaluate the feasibility of short- and medium-distance links at these frequencies and analyze the requirements from the transceiver architecture and technology, antennas, and modulation scheme points of view. Technical challenges are discussed, and design options highlighted; finally, a performance evaluation quantifies the benefits of millimeter- wave systems with respect to current cellular technologies.

The ability of using dispersed generation (DG) in the distribution system restoration service in the context of smart networks is presented in this paper. The objectives are to reduce the consequences due to a major blackout in terms of the out-of-service load volume, and the duration of restoration process. Based on knapsack problem formulation and network represented graph modeling, a new restoration procedure for distribution network is proposed. An adapted branch-and-bound algorithm is then used to solve the problem. It maximizes the restored loads in distribution by using the DG availability. Simulation results on a study case will be shown to illustrate the proposed procedure and quantify the benefit of using DG in critical situations.

This article presents the impact of the performance of an FC and control strategies on the benefits of hybridization of fuel cell/supercapacitor hybrid sources for vehicle applications. Then, the storage device can complement the main source to produce the compatibility and performance characteristics needed in a load. The studies of two hybrid power systems for vehicle applications, FC/battery and FC/supercapacitor hybrid power sources, are explained. Experimental results with small-scale devices (a PEMFC of 500 W, 40 A, and 13 V; a lead-xicid battery module of 33 Ah and 48 V; and a supercapacitor module of 292 F, 500 A, and 30 V) in laboratory will illustrate the performance of the system during motor-drive cycles.

This paper presents a framework for studying design thinking. Three paradigmatic approaches are described to measure design cognitive processes: design cognition, design physiology and design neurocognition. Specific tools and methods serve each paradigmatic approach. Design cognition is explored through protocol analysis, black-box experiments, surveys and interviews. Design physiology is measured with eye tracking, electrodermal activity, heart rate and emotion tracking. Design neurocognition is measured using electroencephalography, functional near infrared spectroscopy and functional magnetic resonance imaging. Illustrative examples are presented to describe the types of results each method provides about the characteristics of design thinking, such as design patterns, design reasoning, design creativity, design collaboration, the co-evolution of the problem solution space, or design analysis and evaluation. The triangulation of results from the three paradigmatic approaches to studying design thinking provides a synergistic foundation for the understanding of design cognitive processes. Results from such studies generate a source of feedback to designers, design educators and researchers in design science. New models, new tools and new research questions emerge from the integrated approach proposed and lay down future challenges in studying design thinking.

A novel concept, called the propagator, based upon a partition of the steering vectors matrix and, correlatively, of the received signals' cross-spectral matrix (CSM), is introduced for the characterization of source and noise subspaces without reference to the CSM eigenstructure. A localization technique can thereby be applied for uncorrelated or partially correlated sources with an arbitrary propagation model, which is directly comparable to the MUSIC algorithm. Given the signals produced by one particular source on some of the sensors, the propagator permits the extrapolation of the signals received by the remaining sensors. Various applications of this property can be found. An example is given concerning the estimation of the sensors' complex gains.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Abstract There is a growing interest in adaptive facade technologies to counter overheating problems and well‐being concerns in smart and high‐performance buildings. However, traditional literature review studies do not necessarily provide deep insights into the future trends of adaptive facade technologies. To address these limitations, this paper proposes a novel conceptual framework and technological classification for adaptive facades in the future. Our research methodology includes a literature review expert interviews and content analysis. In‐depth interviews with 27 international adaptive facade experts were conducted with a focus on the European context. The results categorize the adaptive facade technologies under four promising families and present a conceptual framework that identifies human‐centered design, smart building operating systems, service‐driven solutions, circularity, and materials as the main drivers of the facade technological advancements. Overall, this methodology yields new and rich qualitative knowledge related to adaptive facades; however, it has certain limitations, such as being time‐consuming. The research provides insights on future delivery processes and the future structural trends of adaptive facades. The new categorization and framework articulate the multifunctionality and performance requirements of facade technologies including smartness, automation, comfort, and well‐being.

The effect of localized damage (interface states and/or trapped charges) on the ohmic region characteristics of electrically stressed MOSFET's is analyzed using the two-dimensional (2-D) solution of Poisson's equation. The device aging induced by hot-electron injection is summarized in the formation of a narrow defective interface region whose nature, extension, and position in the channel are the parameters of our investigation. Fundamental differences are observed between the effect of interface states and that of fixed oxide charges. In addition, the channel conductance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</tex> is shown to be greatly influenced by the extension and position of the zone of defects. The correlation between the degradation of the maximum transconductance and that of the threshold voltage is modeled and demonstrated to be an important tool in the diagnosis of device degradation. The interaction between the damaged and undamaged channel regions is found to produce a transconductance overshoot that attenuates the aging effects. A negative transconductance degradation (i.e., transconductance increase) in the case of positively charged defects and an apparent amelioration of the mobility degradation factor θ in the case of localized acceptor states are two direct consequences of this effect. The errors arising from the modeling of aged devices with 1-D homogeneous analytical models are outlined.

The sense of embodiment refers to the sensations of being inside, having, and controlling a body. In virtual reality, it is possible to substitute a person’s body with a virtual body, referred to as an avatar. Modulations of the sense of embodiment through modifications of this avatar have perceptual and behavioural consequences on users that can influence the way users interact with the virtual environment. Therefore, it is essential to define metrics that enable a reliable assessment of the sense of embodiment in virtual reality to better understand its dimensions, the way they interact, and their influence on the quality of interaction in the virtual environment. In this review, we first introduce the current knowledge on the sense of embodiment, its dimensions (senses of agency, body ownership, and self-location), and how they relate the ones with the others. Then, we dive into the different methods currently used to assess the sense of embodiment, ranging from questionnaires to neurophysiological measures. We provide a critical analysis of the existing metrics, discussing their advantages and drawbacks in the context of virtual reality. Notably, we argue that real-time measures of embodiment, which are also specific and do not require double tasking, are the most relevant in the context of virtual reality. Electroencephalography seems a good candidate for the future if its drawbacks (such as its sensitivity to movement and practicality) are improved. While the perfect metric has yet to be identified if it exists, this work provides clues on which metric to choose depending on the context, which should hopefully contribute to better assessing and understanding the sense of embodiment in virtual reality.

Following the Galerkin projective technique, first-order triangular finite elements are derived for the nonlinear diffusion equation-in the general form which includes both time-dependent and notional terms. The method is applied to a simplified model of a single-sided linear induction motor, for which the finite element equations are solved by an implicit method in time, and iteratively in space. The results suggest that the screening effect of eddy currents in the iron is quite strong.

Many canal control methods and algorithms have been developed, but only some of them are being used on operating canal projects. As a part of the ASCE task committee on canal automation algorithms, this paper discusses field application of automatic control algorithms. Based on available data, information is presented on the implementation of canal algorithms. These algorithms are categorized as implicit algorithms in self-regulating gates, local automatic feedback controllers, and supervisory control algorithms. For each algorithm, brief information is provided on water projects that are using the algorithm, the type of application, implementation history, and algorithm performance.

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We performed an experiment of surface-enhanced second-harmonic generation on silver gratings of various groove depths. Using gratings with constant periodicity (1800 grooves/mm), we measured the intensity of the diffracted orders 0 and -1 at the second-harmonic frequency. This was done by varying the angle of incidence of the pump beam and also testing several different groove depths. We get an enhancement of the second-harmonic intensity by a factor of about 36 as compared to the flat silver case. Our data show that this enhancement, which arises from the surface-plasmon resonance at the pump frequency, depends strongly on the groove depth. In addition, we demonstrate an important and new result: There exists an optimum value of the groove depth for which this enhancement is maximum. A good agreement is found between our measurements and results predicted by the theory of diffraction in nonlinear optics [R. Reinisch and M. Neviere, Phys. Rev. B 28, 1870 (1983)].

Abstract. The Town Energy Balance (TEB) model has been refined and improved in order to explicitly represent street trees and their impacts on radiative transfer: a new vegetated stratum on the vertical plane, which can shade the road, the walls, and the low vegetation has been added. This modification led to more complex radiative calculations, but has been done with a concern to preserve a certain level of simplicity and to limit the number of new input parameters for TEB to the cover fraction of trees, the mean height of trunks and trees, their specific leaf area index, and albedo. Indeed, the model is designed to be run over whole cities, for which it can simulate the local climatic variability related to urban landscape heterogeneity at the neighborhood scale. This means that computing times must be acceptable, and that input urban data must be available or easy to define. This simplified characterization of high vegetation necessarily induces some uncertainties in terms of the solar radiative exchanges, as quantified by comparison of TEB with a high-spatial-resolution solar enlightenment model (SOLENE). On the basis of an idealized geometry of an urban canyon with various vegetation layouts, TEB is evaluated regarding the total shortwave radiation flux absorbed by the elements that compose the canyon. TEB simulations in summer gathered best scores for all configurations and surfaces considered, which is precisely the most relevant season to assess the cooling effect of deciduous trees under temperate climate. Mean absolute differences and biases of 6.03 and +3.50 W m−2 for road, respectively, and of 3.38 and +2.80 W m−2 for walls have been recorded in vegetationless canyons. In view of the important incident radiation flux, exceeding 1000 W m−2 at solar noon, the mean absolute percentage differences of 3 % for both surfaces remain moderate. Concerning the vegetated canyons, we noted a high variability of statistical scores depending on the vegetation layout. The greater uncertainties are found for the solar radiation fluxes received and absorbed by the high vegetation. The mean absolute differences averaged over the vegetation configurations during summertime are 21.12 ± 13.39 W m−2 or 20.92 ± 10.87 % of mean absolute percentage differences for the total shortwave absorption, but these scores are associated with acceptable biases: −15.96 ± 15.93 W m−2.

The research discussed in this article is motivated by the search for an optimal classification of the different types of atrial fibrillation (AF) on the basis of recorded atrial signals. This would facilitate the selection of an optimal therapy. This article focuses on the biophysical models of the genesis of ECG waveforms during AF. The model of the electric activity of the atria was found to have sufficient realism to be used to describe the electric sources during AF. The inclusion of the volume conduction model resulted in electrocardiographic signals that are in all aspects similar to those observed clinically. The model is currently applied to solve various problems related to optimal signal preprocessing and extraction of features in AF signals for the classification of AF abnormalities. The biophysical model of the atrial activity is an essential element in this research, since it is capable of describing the electric source specifications derived from different hypotheses relating to the etiology of AF

Résumé La thématique de la marche en ville occupe la littérature du xix e siècle. Au point qu’aujourd’hui, la figure du flâneur de Benjamin domine encore nos représentations. Pour autant, si marcher en ville requiert un art du voir dont le flâneur demeure un artiste accompli, il engage aussi le corps et les sens du piéton. Le propos de cet article est de révéler cette dimension sensorielle de la marche. Il s’appuie sur une lecture des travaux récents de l’anthropologie, de la sociologie et de l’urbanisme. Décrite comme une « technique du corps », comme un « acte social ordinaire », la marche reste « l’instrument de composition de la ville ». Elle demeure surtout un moyen de s’ancrer à la ville.

In this paper we present an immersive virtual reality user study aimed at investigating how customers perceive and if they would purchase non-standard (i.e. misshaped) fruits and vegetables (FaVs) in supermarkets and hypermarkets. Indeed, food waste is a major issue for the retail sector and a recent trend is to reduce it by selling non-standard goods. An important question for retailers relates to the FaVs' “level of abnormality” that consumers would agree to buy. However, this question cannot be tackled using “classical” marketing techniques that perform user studies within real shops since fresh produce such as FaVs tend to rot rapidly preventing studies to be repeatable or to be run for a long time. In order to overcome those limitations, we created a virtual grocery store with a fresh FaVs section where 142 participants were immersed using an Oculus Rift DK2 HMD. Participants were presented either “normal”, “slightly misshaped”, “misshaped” or “severely misshaped” FaVs. Results show that participants tend to purchase a similar number of FaVs whatever their deformity. Nevertheless participants' perceptions of the quality of the FaV depend on the level of abnormality.

The coherence of third generation synchrotron beams makes a trivial form of phase-contrast imaging possible. It is based on propagation and corresponds to the defocusing technique of electron microscopy. The propagation technique can be used either in a qualitative way, mainly useful for edge- detection, or in a quantitative way, involving numerical retrieval of the phase from images recorded at different distances (typically three or four) from the sample. The combination with tomography allows to reconstruct the electron density in the sample with micrometer resolution. This combined approach is called holotomography. It was applied to several problems in materials and life sciences when it is crucial to enhance the sensitivity or reduce the dose compared to absorption tomography. Pure phase objects such as foams and fleece structures can be imaged with excellent contrast and resolution. Holotomography turned out to be a invaluable tool to study semi-solid materials with two metallurgical phases that have similar attenuation coefficients. The attenuation and density map yield in this case complementary information, the latter being the useful one to study the connectivity of the solid phase. The dose reduction and increased sensitivity in phase imaging are crucial for imaging thick (millimeter range) biological samples in their natural, wet environment. Results obtained on Arabidopsis plant indicate the possibility to investigate at the micron scale the spatial organisation of plant cells.

An analytical model of conductance and transconductance for enhanced-mode MOSFETs is presented. Based on an inversion charge dependent mobility, the model enables the calculation of the conductance and transconductance MOSFET characteristics against several parameters such as bulk bias, oxide thickness, channel length, source-drain series resistance, surface states density, mobility reduction factor and/or potential fluctuation rate. The maximum field effect mobility and the extrapolated threshold voltage deduced from transfer characteristics are then investigated as a function of these parameters. It is finally emphasized that this MOSFET modelprovides a simple but useful tool for analysing the limitations of scaled down devices. Un modéle analytique de conductance et de transconductance pour MOSFET á enrichissement est présenté. Ce modele basé sur une dépendance de la mobilité avec la charge d'inversion permet de calculer la conductance et la transconductance de MOSFETs en fonction des paramétres tels que la polarisation du substrat, L'épaisseur de L'oxide de grille, la longueur du canal,la résistance série source-drain, la densité d'états d'interface, le facteur de réduction de la mobilité et/ou le taux de fluctuation de potentiel. Le maximum de la mobilité d'effet de champ et la tension de seuil extrapolée déduites des caractéristiques de transfert sont analysées en fonction de ces parametres. II est finalement soulignéque ce modéle de MOSFET procure un outil simple mais utile pour L'investigation des limitations propres á la miniaturisation des dispositifs.

Thermal dissipation in power electronics systems is becoming an extremely important issue with the continuous growth of power density in their components. The primary cause of failure in this equipment is excessive temperatures in the critical components, such as semiconductors and transformers. This problem is particularly important in power electronic systems for space applications. These systems are usually housed in completely sealed enclosures for safety reasons. The effective management of heat removal from a sealed enclosure poses a major thermal-design challenge since the cooling of these systems primarily rely on natural convection. In this context, the presented paper treats the heat pipes as effective heat transfer devices that can be used to raise the thermal conductive path in order to spread a concentrated heat source over a larger surface area. As a result, the high heat flux at the heat source can be reduced to a smaller and manageable level that can be dissipated through conventional cooling methods. The objective of our work is to describe the feasibility of a cooling system with miniature heat pipes embedded in a direct bonded copper (DBC) structure. The advantage of this type of heat pipe is the possibility for implementation of the component layout on the heat pipe itself, which eliminates the existence of a thermal interface between the device and the cooling system

This paper presents an analytical electromagnetic model of a rectilinear actuator. The model is based on a reluctance network, which can be solved with the same techniques as for an electric circuit. The analytical model was originally built to be used with an algorithm of geometric optimization for design purposes. The authors first show the way in which leakage flux are taken into account. They then describe the innovative method they have developed for the reluctance evaluation of different parts of the actuator. The method considers magnetic saturation and flux routes in remarkable cylindrical geometries. The authors also describe an equivalent model of the air gap, which gives the values of force applied on the moving part and the corresponding reluctance value of the air gap. An evaluation of the model accuracy by comparison with a numeric determination (finite elements) makes it possible to carry out further optimizations of the rectilinear actuator. Finally, the authors interpret the model deviations, and they suggest corresponding improvements of the analytical model.