Neuroimaging the effects of light on non-visual brain functions

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Circadian, sleep-wake dependent or both? A preface to the special issue “Circadian rhythm and sleep-wake dependent regulation of behavior and brain function

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Romization: Early Deployment and Customization of Java Systems for Restrained Devices

Memory is the scarcest ressource of embedded and restrained devices. This paper studies the memory footprint benefit of pre-deploying embedded Java systems up to their activation. We find out that the more the system is deployed off-board, the more it can be efficiently and automatically customized in order to reduce its final size. This claim is validated experimentally through the production of memory images that are between 10% and 45% the size of their J2ME CLDC counterparts, while using the J2SE API and being ready-to-run without any further on-board initialization. Embedded solutions like J2ME degrade the Java environment and API right fromtheir specification, limiting their usage perspectives. By contrast, our romization scheme generates and specializes a custom-tailored Java system and API for embedded applications being deployed in a full-fledged J2SE environment

The Web of Things: interconnecting devices with high usability and performance

International audienceIn this paper, we show that Web protocols and technologies are good candidates to design the Internet of Things. This approach allows anyone to access embedded devices through a Web application, via a standard Web browser. This Web of Things requires to embed Web servers in hardware-constrained devices. We first analyze the traffics embedded Web servers have to handle. Starting from this analysis, we propose a new way to design embedded Web servers, using a dedicated TCP/IP stack and numerous cross-layer off-line pre-calculation (where information are shared between IP, TCP, HTTP and the Web application). We finally present a prototype -- named Smews -- as a proof of concept of our proposals. It has been embedded in tiny devices (smart cards, sensors and other embedded devices), with a requirement of only 200 bytes of RAM and 7 kilo-bytes of code. We show that it is significantly faster than other state of the art solutions. We made Smews source code publically available under an open-source license

Serving Embedded Content via Web Applications: Model, Design and Experimentation

International audienceEmbedded systems such as smart cards or sensors are now widespread, but are often closed systems, only accessed via dedicated terminals. A new trend consists in embedding Web servers in small devices, making both access and application development easier. In this paper, we propose a TCP performance model in the context of embedded Web servers, and we introduce a taxonomy of the contents possibly served by Web applications. The main idea of this paper is to adapt the communication stack behavior to application contents properties. We propose a strategies set fitting with each type of content. The model allows to evaluate the benefits of our strategies in terms of time and memory charge. By implementing a real use case on a smart card, we measure the benefits of our proposals and validate our model. Our prototype, called Smews, makes a gap with state of the art solutions both in terms of performance and memory charge

Cross-layer enhancement of Web servers dedicated to small devices

De nos jours, les systèmes embarqués sont de plus en plus nombreux et ont un besoin grandissant d'accessibilité. Au lieu d'utiliser des protocoles dédiés, imposant l'utilisation de logiciels clients et serveurs, nous soutenons que l'utilisation de serveurs Web sur ces cibles en augmente l'accessibilité ainsi que la maintenabilité et facilite le développement. Ainsi, tout le monde peut accéder et configurer un routeur, un capteur de terrain ou un système domotique depuis n'importe quel ordinateur ou PDA, via un simple navigateur Web. En utilisant les technologies modernes du Web telles qu'AJAX, des applications interactives peuvent être servies. Cependant, cette solution est techniquement difficile à mettre en oeuvre à cause des limitations matérielles des systèmes embarqués ciblés (souvent un CPU à quelques MHz et seulement quelques kilo-octets de RAM), comparées à la lourdeur des serveurs Web classiques (et des protocoles du Web). Dans ce rapport, nous présentons tout d'abord une analyse transversale des protocoles TCP/IP lorsqu'utilisés pour servir des applications Web dynamiques. Nous testons des serveurs Web embarqués existants et analysons leurs performances. A partir de cette analyse, nous proposons de nouvelles solutions pour concevoir des serveurs Web efficaces et peu consommateurs de mémoire. Nous avons implémenté toutes nos propositions, engendrant un nouveau serveur Web embarqué, capable de servir efficacement des applications Web dynamiques avec une consommation en RAM de moins d'un kilo-octet, sans aucun système sous-jacent

Smews: Smart and Mobile Embedded Web Server

International audienceIn this paper, we show that Web protocols and technologies are good candidates to design the Internet of Things, through a user-centric architecture (the user simply has to use a standard Web browser). We detail how this Web of Things can handle typical embedded devices interaction needs. We discuss the technical feasibility of embedded Web servers, and, thanks to an analysis of the Web protocols, we propose new cross-layer solutions for efficient tiny embedded Web servers design. The problem of event notification for Web applications is also discussed. We finally present a prototype -- named Smews -- as a proof of concept of the Web of Things. Smews implements our proposals and has been embedded in tiny devices (smart cards, sensors and other embedded devices), with a requirement of only 200~bytes of volatile memory and 7~kilo-bytes of code. We show that it is significantly faster than other state of the art solutions. We made Smews source code publically available under an open-source license

Consistency and scalability in event notification for embedded Web applications

International audienceA new way to interact with small devices consists in embedding tiny Web servers, allowing the devices to serve fully-fledged Web applications. When the device needs to keep its users up-to-date of its internal state, the Web application has to use an event publication solution. Several works have recently been conducted in order to evaluate the trade-offs of various Web-based event notification solutions. In this paper, we propose to evaluate the feasibility of event notification in embedded Web applications. We conduct a large set of experiments in order to compare various push and pull based approaches for embedded systems. We show that a push-based approach can be very efficient in most situations, both in terms of client consistency and of scalability

A Low-Footprint Java-to-Native Compilation Scheme Using Formal Methods

Ahead-of-Time and Just-in-Time compilation are common ways to improve runtime performances of restrained systems like Java Card by turning critical Java methods into native code. However, native code is much bigger than Java bytecode, which severely limits or even forbids these practices for devices with memory constraints. In this paper, we describe and evaluate a method for reducing natively-compiled code by suppressing runtime exception check sites, which are emitted when compiling bytecodes that may potentially throw runtime exceptions. This is made possible by completing the Java program with JML annotations, and using a theorem prover in order to formally prove that the compiled methods never throw runtime exceptions. Runtime exception check sites can then safely be removed from the generated native code, as it is proved they will never be entered. We have experimented our approach on several card-range and embedded Java applications, and were able to remove almost all the exception check sites. Results show memory footprints for native code that are up to 70% smaller than the non-optimized version, and sometimes as low than 115% the size of the Java bytecode when compiled for ARM thumb

Trophic niches of thirteen damselfishes (Pomacentridae) at the Grand Récif of Toliara, Madagascar

The damselfishes, with more than 340 species, constitute one of the most important families that live in the coral reef environment. Most of our knowledge of reef-fish ecology is based on this family, but their trophic ecology is poorly understood. The aim of the present study was to determine the trophic niches of 13 sympatric species of damselfishes by combining stable isotope (d15N and d13C) and stomach content analyses. Isotopic signatures reveal three main groups according to their foraging strategies: pelagic feeders (Abudefduf sexfasciatus, A. sparoides, A. vaigiensis, Chromis ternatensis, C. dimidiata, Dascyllus trimaculatus and Pomacentrus caeruleus), benthic feeders (Chrysiptera unimaculata, Plectroglyphidodon lacrymatus and Amphiprion akallopisos) and an intermediate group (D. aruanus, P. baenschi and P. trilineatus). Stomach contents reveal that planktonic copepods and filamentous algae mainly represent the diets of pelagic feeders and benthic feeders, respectively. The intermediate position of the third group resulted from a partitioning of small planktonic prey, small vagile invertebrates and filamentous algae. In this last feeding group, the presence of a wide range of d13C values in P. trilineatus suggests a larger trophic niche width, related to diet-switching over time. Some general considerations about the feeding habits of damselfishes reveal that their choice of habitat on the reef and their behavior appear to be good predictors of diet in this group. Benthic (algae and/or small invertebrates) feeders appear to be solitary and defend a small territory on the bottom; zooplankton feeders remain in groups just above the reef, in the water column.Peer reviewe