978 research outputs found
Algorithme de récupération de porteuse pourdes systèmes de communication de lumièrevisible adaptées au contexte
International audienceLa communication parlumì ere visible (VLC) suscite beaucoup d'intérêt à la fois dans la communauté scientifique et industrielle. En dépit de cet intérêt croissant, VLC en est encorè a ses balbutiements et il a été réalisé que les techniques de communication de contrôle physique et d'accès au support (MAC) bien évaluées dans les contextes de communication traditionnels (sans fil) ne peuvent pas être appliquées dans le domaine VLC. En effet, les interférences externes sont de nature et d'impact différents. Les lumières artificielles et la lumière du soleil peuvent perturber la communication et nous avons observé que les conditions extérieures changent demanì ere imprévisible et abrupte. Sur la base de ces considérations, il a été réalisé que les émetteurs et les récepteurs doivent être équipés d'une sorte d'intelligence les rendant capables de réagir dynamiquement aux changements externes afin de rendre le système de communication plus robuste. Dans ce travail, nous avons étudié l'impact de la longueur du préambule afin de réaliser un mécanisme de récupération de porteuse efficace entre unémetteurun´unémetteur et un récepteur. Nous avons remarqué que différentes conditions externes nécessitent des longueurs de préambule différentes afin de réaliser une récupération de porteuse efficace avec un faible impact en termes de taux d'erreur de morsure (BER). Nous avons étudié les différentes conditions externes et leur impact sur le système de communication et nous avons proposé une formulation de bandit multi-bras de la définition de la longueur du préambule basée sur l'approche d' échantillonnage de Thompson. Cette logique d'intelligence artificielle a été implémentée côté récepteur et une preuve de concept a été implémentée afin de valider l'approche dans un environnement réel avec de réels changements externes. Les résultats montrent que l'approche d' échantillonnage de Thompson est très réactive aux conditions externes
A Noise Mitigation Approach for VLC Systems
International audienceVisible Light Communication (VLC) is based on the dual use of the illumination infrastructure for wireless data communication. The major interest on this communication technology lies on its specific features to be a secure, cost-effective wireless technology. Recently, this technology has gained an important role as potential candidate for complementing traditional RF communication systems. Anyway a major issue for the VLC development is a deep comprehension of the noise and its impact on the received signal at the receiver. In this work, we present a simple but effective approach to analyze the noise and drastically reduce it through a signal processing method. In order to validate the effectiveness of this analytical approach, we have developed an USRP-based testbed. Experimental results have been carried out by evaluating the symbol error rate (SER) and show the effectiveness of the noise mitigation approach in different interference conditions and at different distance between the transmitter and the receiver
Emerging treatments in the management of psoriasis: biological targeting with ustekinumab
Psoriasis is a chronic, genetically determined, immune-mediated, inflammatory skin disease affecting approximately 2% to 3% of Caucasian population. Given the well-established role of the immuno-mediated inflammation in the pathogenesis of psoriasis, in the past few years several key steps in the pathogenesis of this disease have been elucidated and the increased knowledge led to the development of specific drugs, commonly defined as “biologics” targeting one or more of these steps. At present an anti-CD11a antibody (efalizumab), an anti-LFA3/CD2 receptor (alefacept) and 3 antitumor necrosis factor alpha agents (adalimumab, etanercept, infliximab) are now commercially available for the treatment of both psoriasis and psoriatic arthritis. Recent studies have demonstrated that interleukins (IL) 12 and 23 play an important role in the pathophysiology of psoriasis. In fact members of the IL-12 family of cytokines have the potential to act as the next major cytokine(s) in pathogenesis and the treatment of psoriasis. Ustekinumab (CNTO 1275, Centocor Inc, Malvern, PA, USA) is a human monoclonal antibody that binds to the shared p40 protein subunit of human interleukins 12 and 23 with high affinity and specificity, thereby preventing interaction with their surface IL-12Rβ1 receptor. Different clinical studies have been conducted to date. In particular a phase II study and two phase III studies, PHOENIX 1 together with PHOENIX 2, show very encouraging results. This review reports on the latest progress made in the clinical use of biologic drugs for psoriasis focusing on the new human IL-12/23 monoclonal antibody, ustekinumab, for psoriasis
Generation of an ultrastable 578 nm laser for Yb lattice clock
In this paper we described the development and the characterization of a 578 nm laser source to be the clock laser for an Ytterbium Lattice Optical clock. Two independent laser sources have been realized and the characterization of the stability with a beat note technique is presente
A Symphony of Regulations Centered on p63 to Control Development of Ectoderm-Derived Structures
The p53-related transcription factor p63 is critically important for basic cellular functions during development of the ectoderm and derived structure and tissues, including skin, limb, palate, and hair. On the one side, p63 is required to sustain the proliferation of keratinocyte progenitors, while on the other side it is required for cell stratification, commitment to differentiate, cell adhesion, and epithelial-mesenchymal signaling. Molecules that are components or regulators of the p63 pathway(s) are rapidly being identified, and it comes with no surprise that alterations in the p63 pathway lead to congenital conditions in which the skin and other ectoderm-derived structures are affected. In this paper, we summarize the current knowledge of the molecular and cellular regulations centered on p63, derived from the comprehension of p63-linked human diseases and the corresponding animal models, as well as from cellular models and high-throughput molecular approaches. We point out common themes and features, that allow to speculate on the possible role of p63 downstream events and their potential exploitation in future attempts to correct the congenital defect in preclinical studies
Neurobehavioural Effects of Monochromatic Light Exposure
Our study is an attempt of partial replication of the study on the effects of monochromatic lights from Sahin and Figueiro (2013).
We conducted a two-way crossover comparison between the effects of two Light Emitting Diodes (LED) Monochromatic Lights (Red, Blue) administered at 40lx. In the first part (Part I) we explored the possibility of an alerting effect of light comparing basal morning alertness levels, post prandial alertness and post light exposure. According to previous results by the authors (Sahin and Figueiro, 2013)
In the second part (Part II) we were partially replicating the study by Sahin and Figueiro (2013). Adopting the same light technology and specifications, alerting effect of light were evaluated by means of repeated EEG measurements of alertness. Our study showed that there is no effect of Monochromatic Light exposure on subjective and objective measure of alertness. Results observed in the analysis of EEG signal highlight a possible role of subcortical regions responsible for arousal regulation that are influenced by exposure to lights of short wavelength. These effects have been found during light exposure; but our results support the possibility that these alerting effects can influence EEG activity even after Monochromati
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