Baudrit C.,French National Institute for Agricultural Research |
Destercke S.,Sorbonne Universites |
Wuillemin P.H.,University Pierre and Marie Curie
Information Sciences | Year: 2016
Modeling complex dynamical systems from heterogeneous pieces of knowledge varying in precision and reliability is a challenging task. We propose the combination of dynamical Bayesian networks and of imprecise probabilities to solve it. In order to limit the computational burden and to make interpretation easier, we also propose to encode pieces of (numerical) knowledge as probability intervals, which are then used in an imprecise Dirichlet model to update our knowledge. The idea is to obtain a model flexible enough so that it can easily cope with different uncertainties (i.e., stochastic and epistemic), integrate new pieces of knowledge as they arrive and be of limited computational complexity. © 2016 Elsevier Inc.
Dorzhiev V.,Novosibirsk State Technical University |
Karami A.,Sorbonne Universites |
Basset P.,University Paris Est Creteil |
Dragunov V.,Novosibirsk State Technical University |
Galayko D.,Sorbonne Universites
Journal of Physics: Conference Series | Year: 2014
The paper is devoted to a novel study of monophase MEMS electrostatic Vibration Energy Harvester (e-VEH) with conditioning circuit based on Bennet's doubler. Unlike the majority of conditioning circuits that charge a power supply, the circuit based on Bennet's doubler is characterized by the absence of switches requiring additional control electronics, and is free from hardly compatible with batch fabrication process inductive elements. Our experiment with a 0.042 cm3 batch fabricated MEMS e-VEH shows that a pre-charged capacitor as a power supply causes a voltage increase, followed by a saturation which was not reported before. This saturation is due to the nonlinear dynamics of the system and the electromechanical damping that is typical for MEMS. It has been found that because of that coupled behavior there exists an optimal power supply voltage at which output power is maximum. At 187 Hz / 4 g external vibrations the system is shown to charge a 12 V supply with a output power of 1.8 μW. © Published under licence by IOP Publishing Ltd.
Blain S.,Sorbonne Universites |
Blain S.,French National Center for Scientific Research |
Capparos J.,Sorbonne Universites |
Capparos J.,French National Center for Scientific Research |
And 6 more authors.
Biogeosciences | Year: 2015
During KEOPS2 (Kerguelen Ocean and Plateau Compared Study 2), we determined dissolved inorganic and organic nitrogen and phosphorus species in the naturally fertilized region of Kerguelen Island (Southern Ocean). Above 150 m, stations were clearly separated by the polar front (PF), with concentrations of NO3-, NO2- and PO43- overall lower north of the PF than south. Though less pronounced, a similar trend was detectable for dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP). At all stations offshore and above the plateau, a subsurface maximum of NH4+ was observed between 50 and 150 m. We examined nutrient stoichiometry by calculating the linear combination N∗ Combining double low line [NO3-]-16 [PO43-]. The majority of stations and depths revealed N∗ close to g'3 Î1/4M; however, for surface waters north of the PF, N∗ increased up to 6 Î1/4M. This suggests a preferential uptake of PO43- versus NO3- by fast-growing diatoms. Using the tracer TNxs Combining double low line [TDN]-16[TDP] (TDN, total dissolved nitrogen; TDP, total dissolved phosphorus) revealed that the dissolved organic fraction significantly contributed to changes in TNxs. TNxs values were negative for most stations and depths, and relatively constant in the 0-500 m layer. As for N∗, the stations north of the PF had higher TNxs in the 0-100 m layer. We discuss this stoichiometric anomaly with respect to possible external sources and sinks of N and P. Additional data collected in February 2013 at two sites revealed the occurrence of a subsurface minimum of N∗ located just below the pycnocline, which denotes a layer where remineralization of particulate organic matter with low N : P ratio P, possibly associated with preferential remineralization of P versus N, persists throughout the season. © 2015 Author(s).
Chirichella C.,Telecom ParisTech |
Rossi D.,Telecom ParisTech |
Testa C.,Telecom ParisTech |
Friedman T.,Sorbonne Universites |
Pescape A.,University of Naples Federico II
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013
"Bufferbloat" is the growth in buffer size that has led Internet delays to occasionally exceed the light propagation delay from the Earth to the Moon. Manufacturers have built in large buffers to prevent losses on Wi-Fi, cable and ADSL links. But the combination of some links' limited bandwidth with TCP's tendency to saturate that bandwidth results in excessive queuing delays. In response, new congestion control protocols such as BitTorrent's uTP/LEDBAT aim at explicitly limiting the delay that they add over the bottleneck link. This work proposes and validate a methodology to monitor the upstream queuing delay experienced by remote hosts, both those using LEDBAT, through LEDBAT's native one-way delay measurements, and those using TCP (via the Timestamp Option). © 2013 Springer-Verlag Berlin Heidelberg.
Barbera M.V.,University of Rome La Sapienza |
Stefa J.,University of Rome La Sapienza |
Viana A.C.,French Institute for Research in Computer Science and Automation |
De Amorim M.D.,Sorbonne Universites |
Boc M.,French Atomic Energy Commission
2011 International Conference on Distributed Computing in Sensor Systems and Workshops, DCOSS'11 | Year: 2011
We propose the use of opportunistic delegation as a data traffic offload solution to the recent boost up of mobile data consumption in metropolitan areas, by investigating two main questions: (i) How to gain insights into social mobile networking scenarios? and (ii) How to utilize such insights to design solutions to alleviate overloaded 3G networks?. The purpose of our solution is to leverage usage of mobile applications requiring large data transfers by channeling the traffic to a few, socially selected important users in the network called VIP delegates. The proposed VIP selection strategies are based on social network properties and are compared to the optimal solution (that covers 100% of users with minimum number of VIPs). Our extensive experiments with real and synthetic traces show the effectiveness of VIP delegation both in terms of coverage and required number of VIPs down to 7% in average of VIPs are needed in campuslike scenarios to offload about 90% of the traffic. © 2011 IEEE.
Lertsinsrubtavee A.,University of Cambridge |
Malouch N.,Sorbonne Universites
IEEE Transactions on Mobile Computing | Year: 2016
Spectrum sharing is a key function to provide fairness allocation as well as service satisfaction across multiple users in cognitive radio networks. Even though spectrum sharing can benefit from spectrum handoff to enhance rate performance by switching from unavailable channels to available ones, the negative impact on handoff delay can cause significant service degradation. In this work, we present a hybrid spectrum sharing strategy that includes novel static and dynamic spectrum sharing algorithms based essentially on a rate compensation approach and adapted best fit algorithms. The static scheme is applicable for some specific network configurations where spectrum handoff is not necessary. Conversely, the dynamic scheme can benefit from spectrum handoff to increase the achieved rate and also compensate for the lost rate from the unavailable periods. These two sharing schemes are operated adaptively according to the current network environment. We compare our hybrid strategy with a fully dynamic one and an optimization framework. The proposed hybrid spectrum sharing demonstrates its effectiveness in terms of improving the overall service satisfaction and reducing the number of handoffs while the achieved rate is fulfilling compared to the optimal. © 2016 IEEE.
Honorat A.,Sorbonne Universites |
Potop-Butucaru M.,Sorbonne Universites |
Tixeuil S.,Sorbonne Universites
Theoretical Computer Science | Year: 2014
Most distributed solutions for swarms of oblivious mobile robots consider that individual robots are represented by points that can overlap, which is physically impossible. A recent trend is to consider "fat" robots, i.e. robots that are represented by unit discs and cannot overlap, but still assume that robots can be seen if there exists a point in the unit disc that has a line of sight with the target robot. Again, this does not match practical sensing devices implementations. We propose a new model for sensing devices that originates from embedded omnidirectional cameras, sonars, or lasers found on real robots. This model opens new algorithmic issues since the visibility relation becomes asymmetric. As a case study, we consider the gathering problem for four volumic robots and provide an algorithm to solve the problem in the fully asynchronous setting in our extended model. © 2014 Elsevier B.V.
Blanco M.,Sorbonne universites
Savoirs et Clinique | Year: 2013
We claim that the nickname « Gongora of the psychoanalysis» given in the fifties to Jacques Lacan by a part of his public, according to his own account in one of his writings - involves a creation of meaning. The Spanish baroque poet Luis de Góngora (1561-1627) was criticised, in his time and later, for being abstruse and obscure, almost beyond understanding. A similar reproach was directed at Lacan, and the reasons of the critics and the arguments of the defence are very alike, in spite of the huge gap between both writers. For Lacan as for Góngora, the obscurity stems from a material depth, and not from an ideal profundity. Both take into account, at every step of their discourse, the stratified thickness that every element of language owes to the unique peculiarity of its history. Copyright © 2013 ERES.
Costache V.,Sorbonne Universites |
McDougall A.,Sorbonne Universites |
Dumollard R.,Sorbonne Universites
Biochemical and Biophysical Research Communications | Year: 2014
Like most metazoans, eggs of echinoderms and tunicates (marine deuterostomes, there is no data for the cephalochordates) arrest awaiting fertilization due to the activity of the Mos/MEK/MAPK cascade and are released from this cell cycle arrest by sperm-triggered Ca2+ signals. Invertebrate deuterostome eggs display mainly three distinct types of cell cycle arrest before fertilization mediated by potentially different cytostatic factors (CSF): one CSF causes arrest during meiotic metaphase I (MI-CSF in tunicates and some starfishes), another CSF likely causes arrest during meiotic metaphase II (amphioxus), and yet another form of CSF causes arrest to occur after meiotic exit during G1 of the first mitotic cycle (G1-CSF). In tunicates and echinoderms these different CSF activities have been shown to rely on the Mos//MAPK pathway for establishment and on Ca2+ signals for their inactivation. Despite these molecular similarities, release of MI-CSF arrest is caused by APC/C activation (to destroy cyclin B) whereas release from G1-CSF is caused by stimulating S phase and the synthesis of cyclins. Further research is needed to understand how both the Mos//MAPK cascade and Ca2+ achieve these tasks in different marine invertebrate deuterostomes. Another conserved feature of eggs is that protein synthesis of specific mRNAs is necessary to proceed through oocyte maturation and to maintain CSF-induced cell cycle arrest. Then activation of development at fertilization is accompanied by an increase in the rate of protein synthesis but the mechanisms involved are still largely unknown in most of the marine deuterostomes. How the sperm-triggered Ca2+ signals cause an increase in protein synthesis has been studied mainly in sea urchin eggs. Here we review these conserved features of eggs (arrest, activation and protein synthesis) focusing on the non-vertebrate deuterostomes. © 2014 Elsevier Inc. All rights reserved.
Pedneault E.,Laval University |
Galand P.E.,Sorbonne Universites |
Galand P.E.,CNRS Benthic Ecogeochemistry Laboratory |
Potvin M.,Laval University |
And 2 more authors.
Scientific Reports | Year: 2014
Thaumarchaeota and the gene encoding for a subunit of ammonia monooxygenase (amoA) are ubiquitous in Polar Seas, and some Thaumarchaeota also have a gene coding for ureC, diagnostic for urease. Using quantitative PCR we investigated the occurrence of genes and transcripts of ureC and amoA in Arctic samples from winter, spring and summer. AmoA genes, ureC genes and amoA transcripts were always present, but ureC transcripts were rarely detected. Over a 48â h light manipulation experiment amoA transcripts persisted under light and dark conditions, but not ureC transcripts. In addition, maxima for amoA transcript were nearer the surface compared to amoA genes. Clone libraries using DNA template recovered shallow and deep amoA clades but only the shallow clade was recovered from cDNA (from RNA). These results imply environmental control of amoA expression with direct or indirect light effects, and rare ureC expression despite its widespread occurrence in the Arctic Ocean.