Réverbère

Résumé

Un lampadaire, ou réverbère, est un dispositif d'éclairage public placé en périphérie des voies de circulation publiques et qui s'allume le soir. Si l'on veut que sa lumière n'éblouisse pas les usagers de la voie publique (piétons ou usagers motorisés) la source d'éclairage des réverbères se doit d'être la plus haute et la plus directionnelle (vers le bas) possible ; cependant, la diminution du nombre de réverbères pour raisons économiques (et donc l'augmentation de leur espacement) peut obliger à contrevenir à cette règle. Certains réverbères sont munis de photodétecteurs qui les allument automatiquement au crépuscule ou lorsqu'il fait sombre et qui les éteignent à l'aube ou lorsqu'il fait clair. Étymologie Son synonyme, le mot « lampadaire » provient des lampades. Dans la mythologie grecque, ces nymphes servaient Hécate. Les lampades portaient des torches desquelles émanait un halo de lumière. Le mot « réverbère » vient du Latin reverbero ( « frappe

Source officielle

https://fr.wikipedia.org/wiki/R%C3%A9verb%C3%A8re

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Recently, European Union advocates the smart Solid-State Lighting (SSL). The key factors are a smart-control scheme and an interaction with other networks, such as communication networks and traffic monitoring sensor networks. Public lighting represents a significant share of city total electricity costs, accounting for up to 60% of the budget. The adoption and deployment of new technologies, such as SSL that is based on Light-Emitting Diodes (LED), offer great opportunities to improve efficiencies and reduce costs. When combined with smart light management systems, SSL can save up the electricity used for lighting and significantly reduce energy and maintenance costs compared to current lighting installations. Moreover, streetlights are the infrastructures erecting beside or in the middle of the streets, so they seem to be the ideal observers of the traffic situations. Even though, other functional sensors, e.g., for measuring temperatures, CO2 and even particulate matter 2.5 (PM2.5), could be integrated in the smart-streetlights. Nowadays there are no sensors embedded in commercial available streetlights, except for the infrared motion sensor used only for pedestrian detection since their range is limited to about 10 meters, as well as there are limited networking capabilities, both in data-rate and functionalities, e.g. it is possible the dimming of only the entire file of streetlights. Hence, the idea to develop aWireless Sensor Front-End (WSFE), which is capable of working as motion sensor, namely a Doppler radar sensor, to monitor the road traffic as well as transceiver to communicate with the other network nodes. Such kind of WSFE could enable many streetlights futures, for example the lighting can be adapted to the traffic conditions and the presence of pedestrians on the sideways. Meanwhile, the communication function can build up a wireless network that can be used to manage the streetlight infrastructure and to collect information on traffic conditions, sensor reading, network status and so on. This thesis proposes a 24GHz 4-channel Phased-Array (Ph-A) front-end for smart-streetlight applications. The design exploits a 90nm Complementary Metal-Oxide-Semiconductor (CMOS) technology to benefit of the low-cost offered by CMOS technology. The architecture of the selected front-end allows the implementation of transceivers as well as Doppler radar sensors. Furthermore, the Ph-A technology is applied to the Doppler radar sensor in order to realizemulti-lane road scanning and pedestrian detection. The intercommunication between streetlights is based on a time-sharing mechanism and uses the same FE reconfigured as transceiver.[...]

EPFL2014

Chargement

Building Blocks for a 24 GHz Phased-Array Front-End in CMOS Technology for Smart Streetlights

Cyril Botteron, Pierre-André Farine, Gabriele Tasselli, Ban Wang

According to a recent European Union report, lighting represents a significant share of electricity costs and the goal of reducing lighting power consumption by 20% demands the coupling of light-emitting diode (LED) lights with smart sensors and communication networks. In this context, this paper proposes the integration of these three elements into a smart streetlight, incorporating a 24 GHz phased-array (Ph-A) front-end (FE). The main building blocks of this Ph-A FE integrated in a low cost 90 nm complementary metal-oxide-semiconductor (CMOS) technology are fully characterized. The selected FE’s architecture allows the implementation of transceivers as well as Doppler radar sensors functionalities. More specifically, the Ph-A technology is applied to a Doppler radar sensor in order to realize multi-lane road scanning and pedestrian detection. That way, the smart streetlight can become eco-friendly by turning on the LEDs only when necessary as well as to measure traffic parameters such as vehicle speed, type and direction. Intercommunication between the smart streetlights is based on a time-sharing mechanism that uses the same FE reconfigured as transceiver. Thanks to this functionality, the recorded traffic information can be relayed through adjacent streetlights to a control center, and control commands and warnings can be spread through the network. The system requirements are derived assuming a simplified model of the operating scenario with a typical inter-light distance of 50 m and line-of-sight between lights. The radar range is around 60 m, which allows for continuous coverage from one streetlight to the adjacent one. Meanwhile, a communication range of 140 m is derived as a fundamental requirement for reliable communication between streetlight sensors because it allows bypassing of one node in case of failure. For the developed building blocks — a low-noise amplifier, a variable-gain amplifier, a voltage-controlled oscillator and a vector modulation phase shifter — the design methodology is presented together with measurement results. The system power, consumption, noise figure and gain are estimated by means of a system analysis based on the measured data from the implemented blocks and the state of the art performances for the missing parts. It is shown that the requirements can be fulfilled with a total power consumption of around 375 mW in Doppler radar sensor mode and around 190 mW in transceiver mode. To the authors’ knowledge, this kind of integration is new and overcomes some limitations of the currently used solutions based on infrared sensors and low-throughput communications.

2014

Chargement

Bayesian optimization of visual comfort

David Lindelöf

We propose a self-commissioning, user-adaptive blinds and electric lighting controller for small office rooms. Self-commissioning, in this context, means that the controller builds an internal representation of the room, in particular of the room's daylighting characteristics, automatically and without user input. By user-adaptive, we mean that the illuminances the controller will seek to maintain are derived from a statistical analysis of the user's behaviour on the manually overridable blinds and electric lighting. Self-commission and user-adaptation are implemented by two decoupled software elements. The first element is a method for modeling the daylighting illuminance on arbitrary locations in the office room, when the windows are shaded by one or two venetian blinds (though the method can be generalized to an arbitrary number and kinds of window shadings). It uses the past history of illuminance distributions in the office room for a similar scene configuration, and models the current illuminance on a given point as a linear combination of outdoor global and diffuse irradiance. The second element is an algorithm for the estimation of the user's visual discomfort probability. It is a function of the current illuminance distribution in that office room, and of the past history of the user's interactions with the blinds' and lighting controls. A bayesian formalism is applied to infer the probability that any illuminance distribution should be considered by the user as visually uncomfortable. We describe how these elements have been integrated in a blinds and electric lighting controller. That controller runs today on an office room of the experimental LESO building and we present the results of the algorithm's adaptation to the preferences of that room's user. We have also assessed that controller's performance on computer-simulated virtual office rooms. We have let the controller run for one year simulated time on six different combinations of office room location (Rome and Brussels) and orientation (north, west and south). These simulations have let us evaluate the energy savings made possible with such a controller, and the improvement of the user's visual comfort.

EPFL2007

Chargement

Building Blocks for a 24 GHz Phased-Array Front-End in CMOS Technology for Smart Streetlights

Cyril Botteron, Pierre-André Farine, Gabriele Tasselli, Ban Wang

2014

EPFL2014

Bayesian optimization of visual comfort

David Lindelöf

EPFL2007