Detecting Stellar Lensing of Gravitational Waves with Ground-Based Observatories

We investigate the ability of ground based gravitational wave observatories to detect gravitational wave lensing events caused by stellar mass lenses. We show that LIGO and Virgo possess the sensitivities required to detect lenses with masses as small as $\sim 30 M_\odot$ provided that the gravitational wave is observed with a signal-to-noise ratio of $\sim30$. Third generation observatories will allow detection of gravitational wave lenses with masses of $\sim 1 M_\odot$. Finally, we discuss the possibility of lensing by multiple stars, as is the case if the gravitational radiation is passing through galactic nucleus or a dense star cluster.Comment: PRD accepte

Analytical characterization of inband and outband D2D Communications for network access

Mención Internacional en el título de doctorCooperative short-range communication schemes provide powerful tools to solve interference and resource shortage problems in wireless access networks. With such schemes, a mobile node with excellent cellular connectivity can momentarily accept to relay traffic for its neighbors experiencing poor radio conditions and use Device-to-Device (D2D) communications to accomplish the task. This thesis provides a novel and comprehensive analytical framework that allows evaluating the effects of D2D communications in access networks in terms of spectrum and energy efficiency. The analysis covers the cases in which D2D communications use the same bandwidth of legacy cellular users (in-band D2D) or a different one (out-band D2D) and leverages on the characterization of underlying queueing systems and protocols to capture the complex intertwining of short-range and legacy WiFi and cellular communications. The analysis also unveils how D2D affects the use and scope of other optimization techniques used for, e.g., interference coordination and fairness in resource distribution. Indeed, characterizing the performance of D2D-enabled wireless access networks plays an essential role in the optimization of system operation and, as a consequence, permits to assess the general applicability of D2D solutions. With such characterization, we were able to design several mechanisms that improve system capabilities. Specifically, we propose bandwidth resource management techniques for controlling interference when cellular users and D2D pairs share the same spectrum, we design advanced and energy-aware access selection mechanisms, we show how to adopt D2D communications in conjunction with interference coordination schemes to achieve high and fair throughputs, and we discuss on end-to-end fairness—beyond the use of access network resources—when D2D communications is adopted in C-RAN. The results reported in this thesis show that identifying performance bottlenecks is key to properly control network operation, and, interestingly, bottlenecks may not be represented just by wireless resources when end-to-end fairness is of concern.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Marco Ajmone Marsan.- Secretario: Miquel Payaró Llisterri.- Vocal: Omer Gurewit

Plant-Growth Promoting Microbes Change the Photosynthetic Response to Light Quality in Spinach

In this study, the combined effect of plant growth under different light quality and the application of plant-growth-promoting microbes (PGPM) was considered on spinach (Spinacia oleracea L.) to assess the influence of these factors on the photosynthetic performance. To pursue this goal, spinach plants were grown in a growth chamber at two different light quality regimes, full- spectrum white light (W) and red-blue light (RB), with (I) or without (NI) PGPM-based inoculants. Photosynthesis-light response curves (LRC) and photosynthesis-CO2 response curves (CRC) were performed for the four growth conditions (W-NI, RB-NI, W-I, and RB-I). At each step of LRC and CRC, net photosynthesis (PN), stomatal conductance (gs), Ci/Ca ratio, water use efficiency (WUEi), and fluorescence indexes were calculated. Moreover, parameters derived from the fitting of LRC, such as light-saturated net photosynthesis (PNmax), apparent light efficiency (Qpp), and dark respiration (Rd), as well as the Rubisco large subunit amount, were also determined. In not-inoculated plants, the growth under RB- regime improved PN compared to W-light because it increased stomatal conductance and favored the Rubisco synthesis. Furthermore, the RB regime also stimulates the processes of light conversion into chemical energy through chloroplasts, as indicated by the higher values of Qpp and PNmax in RB compared to W plants. On the contrary, in inoculated plants, the PN enhancement was significantly higher in W (30%) than in RB plants (17%), which showed the highest Rubisco content among all treatments. Our results indicate that the plant-growth-promoting microbes alter the photosynthetic response to light quality. This issue must be considered when PGPMs are used to improve plant growth performance in a controlled environment using artificial lighting

Introduction. Les défis de la gouvernance métropolitaine

Si la question des conditions d’une gouvernabilité des métropoles nous semble à la fois décisive et pragmatique pour comprendre quels projets peuvent façonner ces nouveaux territoires du politique, de l’économique, du social et du culturel, elle nous semble également propice au croisement des préoccupations scientifiques et politiques. C’est à cette double ambition que on entend contribuer, en mettant à profit cette congruence pour se concentrer, selon une pers- pective internationale et transdisciplinaire, sur les obstacles et les conditions de la construction métropolitaine. On l’aura compris, la gouvernance ne peut être réduite aux seuls champs institutionnel et technique. Elle sera ici entendue selon une acception large et plurielle, en transcendant certaines catégories et frontières qui semblent aujourd’hui inopérantes pour penser la question de la construction métropolitaine, et en comparant des situations métropolitaines très contrastées dans des registres différents de points de vue, de stratégies et d’actions urbaines. Les trajectoires métropolitaines sont en effet toutes uniques et l’observation des pro- cessus à l’œuvre nous montre que, en même temps qu’ils sont reconfigurés par des dynamiques structurelles, les territoires et les pouvoirs qui travaillent l’espace des métropoles, façonnent par eux-mêmes les formes propres de leur gouvernance. Comme l’exprimait l’historien Bernard Lepetit, à propos de la transformation des villes de la France Moderne sous l’effet de la révolution industrielle : « Le système urbain participe à son propre devenir, dont il est à la fois, pour utiliser le vocabulaire de la statistique, une variable explicative et une variable expliquée ». (Lepetit, 1996, p. 10). Ce kaléidoscope de trajectoires métropolitaines fait apparaître des convergences qui nous ont conduits à circonscrire et élargir l’acception du terme de gouvernance autour de trois thèmes saillants : les acteurs de la métropole, la fabrique de la métropole et les cultures de la métropol

Convergence to multi-resource fairness under end-to-end window control

International audienceThe paper relates to multi-resource sharing between flows with heterogeneous requirements as arises in networks with wireless links or software routers implementing network function virtualization. Bottleneck max fairness (BMF) is a sharing objective in this context with good performance. The paper shows that BMF results when local fairness is imposed at each resource while flow rates are controlled by an end-to-end window. We analytically prove convergence to BMF under a fluid model when flows share a network limited to 2 resources while numerical results confirm BMF convergence for larger networks. Simulation results illustrate the impact of packetized transmission

On the Impact of IoT Traffic on the Cellular EPC

One of the most disruptive innovations in next- generation cellular networks will be the massive support of Machine Type and IoT (MTC/IoT) communications. This type of communications exhibits very different requirements from traditional cellular traffic: in MTC/IoT, the same base station may need to provide service to thousands of nodes, each of them transmitting small and infrequent data. In this context, it is critical to evaluate the impact of MTC/IoT on the Evolved Packet Core (EPC) network. We do so by quantifying analytically the signaling load on the EPC due to MTC/IoT bearer instantiation in both standard and 3GPP IoT-optimized LTE networks. Our analysis, validated via simulation, provides useful insights on the impact of the traffic load on each component of the EPC, as well as on the system design.This work was supported by the European Commission through the H2020 5G-TRANSFORMER project (Project ID 761536)

Paris, métropoles. Le défi de la gouvernance

Les Mini-Métropolitaines, lancées il y a plus de deux ans par le Secrétariat Général de la Ville de Paris et par Pierre Mansat, l’Adjoint au Maire de Paris en charge de Paris Métropole et des relations avec les collectivités d’Île-de-France, rencontrent un succès croissant. Chaque mois, pour une conférence-débat d’une heure et demie, un expert ou un chercheur vient à la rencontre d’un public de plus en plus divers : cadres territoriaux, enseignants et chercheurs, membres d’associations, acteurs de terrain ou citoyens intéressés par les questions métropolitaines. Il s’agit non seulement de comprendre la métropole parisienne, mais aussi de se familiariser avec les enjeux liés au phénomène de métropolisation à l’oeuvre partout dans le monde. Il est question de Paris mais aussi des autres grandes métropoles mondiales, qu’elles se situent dans les pays industrialisés, émergents ou en voie de développement. Et, dans le même esprit d’ouverture, les Mini-Métropolitaines ont choisi de croiser toutes les disciplines : sociologie, histoire, géographie, urbanisme… Ce numéro 2 des Cahiers rend compte des différentes interventions qui ont rythmé l’année 2011-2012. Au menu : une explication de la gouvernance du Grand Londres (Christian Lefèvre), un point sur l’histoire de l’approvisionnement parisien des Halles à Rungis (Guy Chemla), un bilan sur la fin de la sectorisation scolaire (Marco Oberti), une évocation du rap et de la notion de territoire (Olivier Cachin), un focus sur quinze ans d’expérience de démocratie participative (Philippe Subra), un aperçu de “l’émiettement de la métropole” en de multiples communes périurbaines (éric Charmes), une mise au point sur la biodiversité en ville et sa prise en considération dans les politiques d’aménagement (Philippe Clergeau) et un entretien croisé au sujet de la voiture en ville (Bruno Marzloff et Mathieu Flonneau). Diversité des thèmes abordés, variété des compétences : les Mini-Métropolitaines décryptent la complexité des phénomènes urbains et les enjeux majeurs auxquels doivent faire face les grandes villes du monde avec un regard particulièrement attentif porté sur la métropole parisienne. (Présentation

Distributed PCA-based anomaly detection in telephone networks through legitimate-user profiling

In my thesis I present a distributed mechanism based on Principal Component Analysis (PCA) to profile the behavior of the legitimate users in telephone networks. The idea is to take advantage of probes distributed over the network to obtain a compact snapshot of the users they serve. A collector node collects and effectively combines such information to gather the description of the legitimate-user behavior. Eventually, it distributes the profile to probes, which perform anomaly detection. Experimental results on five weeks of phone data collected by a telecom operator show that the profiling mechanism is stable over time and allows an operator to decentralize the anomaly detection stage directly to its probes. Furthermore, when compared to a centralized-PCA approach, the technique has the advantage of preventing the creation of polluted profiles, since it avoids that widespread anomalies, that are localized within one (or few) probes, enter into the description of the legitimate-user behavior