Sedimentation of particulate matter in the south-west lagoon of New Caledonia : spatial and temporal patterns

Suspended and sedimented particulate materials were assessed monthly at five sites on the south-west lagoon of New Caledonia, from May 1986 to April 1987. Sedimentation of particulate matter was measured using sediment traps for 24 h. Resuspension, which accounted for more than 80% of the total sedimentation, was distinguished to calculate net sedimentation values. The mean net sedimentation rate for the lagoon varied according to the site from 0.481 to 1.157 gC/m2/day with a general mean value of 0.756 gC/m2/day. An increasing gradient from the reef to the shore stations was observed for both suspended and sedimented particles. The standing stocks and the fluxes of suspended particles were maximal in February, during the warm season associated with maximal rainfall, and minimal in August. The high C/N ratio in sedimented material compared to suspended particles indicated that organic matter degradation had occurred preferentially in the water column. The mean particulate organic carbon flux was about twice the lagoon pelagic primary production ; sedimented plant material only accounted for a small part of the organic carbon flux. The major source of sedimented organic carbon was therefore allochthonous and derived both from the reef and the shore. The latter seemed to predominate. Relative uncoupling between benthos and pelagos is suggested. (Résumé d'auteur

Adaptive Probabilistic Flooding for Multipath Routing

In this work, we develop a distributed source routing algorithm for topology discovery suitable for ISP transport networks, that is however inspired by opportunistic algorithms used in ad hoc wireless networks. We propose a plug-and-play control plane, able to find multiple paths toward the same destination, and introduce a novel algorithm, called adaptive probabilistic flooding, to achieve this goal. By keeping a small amount of state in routers taking part in the discovery process, our technique significantly limits the amount of control messages exchanged with flooding -- and, at the same time, it only minimally affects the quality of the discovered multiple path with respect to the optimal solution. Simple analytical bounds, confirmed by results gathered with extensive simulation on four realistic topologies, show our approach to be of high practical interest.Comment: 6 pages, 6 figure

Performance théorique d'un neurone à spikes Integrate-and-Fire

International audienceThis paper focuses on the theoretical performance of a neuro-inspired digital communication, where the input signal is below the activation threshold of the neuron, making the noise crucial for the detection. We first derive the error probability of a neuro-inspired detector build upon a single Integrate-and-Fire (IF) neuron and then extend this result to a IF-based detector build upon multiple neurons. In this case, we propose to optimize the number of neurons in parallel, leading to an error probability below 10 −4 for a large noise range, proving the strength of such an IF-based detector.Ce papier se concentre sur les performances théoriques d'un détecteur neuro-inspiré pour une communication numérique où le signal d'entrée est inférieur au seuil d'activation du neurone, rendant le bruit crucial pour la détection. Nous caractérisons dans un premier temps la probabilité d'erreur d'un tel détecteur basé sur un neurone Integrate-and-Fire (IF), puis étendons ce résultat à un détecteur utilisant plusieurs neurones IF en parallèle. Dans ce cas, nous proposons d'optimiser le nombre de neurones en parallèle, permettant d'atteindre une probabilité d'erreur inférieure à 10 −4 pour une large plage de bruit, prouvant ainsi la puissance d'un tel détecteur IF

Cache Side-Channel Attacks Through Electromagnetic Emanations of DRAM Accesses

Remote side-channel attacks on processors exploit hardware and micro-architectural effects observable from software measurements. So far, the analysis of micro-architectural leakages over physical side-channels (power consumption, electromagnetic field) received little treatment. In this paper, we argue that those attacks are a serious threat, especially against systems such as smartphones and Internet-of-Things (IoT) devices which are physically exposed to the end-user. Namely, we show that the observation of Dynamic Random Access Memory (DRAM) accesses with an electromagnetic (EM) probe constitutes a reliable alternative to time measurements in cache side-channel attacks. We describe the EVICT+EM attack, that allows recovering a full AES key on a T-Tables implementation with similar number of encryptions than state-of-the-art EVICT+RELOAD attacks on the studied ARM platforms. This new attack paradigm removes the need for shared memory and exploits EM radiations instead of high precision timers. Then, we introduce PRIME+EM, which goal is to reverse-engineer cache usage patterns. This attack allows to recover the layout of lookup tables within the cache. Finally, we present COLLISION+EM, a collision-based attack on a System-on-chip (SoC) that does not require malicious code execution, and show its practical efficiency in recovering key material on an ARM TrustZone application. Those results show that physical observation of the micro-architecture can lead to improved attacks

Everlasting sensor networks

Poster for " L'énergie demain. Transition énergétique : recherches et ingénierie " symposium. May 30-31, 2013, MINES ParisTechWithin the team CSAM (Circuits, Systèmes et Applications des Microondes) of IEMN (Institut d'Électronique, de Microélectronique et de Nanotechnologie) and within IRCICA (Institut de Recherche sur les Composants logiciels et matériels pour l'Information et la Communication Avancée - USR CNRS 3080) we develop a research on ultra low power sensor networks. Our goal is to minimize the energy consumption so that the life duration of the network could be infinitely long. We develop studies including nanotechnologies (energy harvesting, storage devices), RF front-ends design, energy management but also radio channel and interference modeling and MAC layer optimization

Synthesis of T-Nb2O5 thin-films deposited by Atomic Layer Deposition for miniaturized electrochemical energy storage devices

Atomic Layer Deposition has been used to grow 30 to 90 nm-thick amorphous Nb2O5 films onto Pt current collectors deposited on Si wafer. While T-Nb2O5 polymorph is obtained by further annealing at 750 °C, the film thickness and the resulting electrode areal capacity are successfully controlled by tuning the number of ALD cycles. The electrochemical analysis reveals a lithium ion intercalation redox mechanism in the T-Nb2O5 electrode. An electrode areal capacity of 8 μAh cm-² could be achieved at 1 C, with only 40% capacity loss at 30 C(2 minutes discharging time). This paper aims at demonstrating the use of Atomic Layer Deposition method in the fabrication of Nb205-based on-chip micro-devices for Internet of Things (IoT) applications

Attacking Block Ciphers

Differential Fault Analysis (DFA) was one of the earliest techniques invented to attack block ciphers by provoking a computational error. In the basic DFA scenario the adversary obtains a pair of ciphertexts both of which encrypt the same plaintext. One of these ciphertexts is the correct result while the other is an erroneous one resulting from a faulty computation. Though applications of DFA to DES and AES have proven to be quite effective, other techniques have also been invented which can threaten block ciphers in different ways. This chapter presents some of these fault analysis methods, including Collision Fault Analysis (CFA) and its close variant Ineffective Fault Analysis (IFA). These methods depart from DFA by the fault model they rely on, by their ability to defeat classical countermeasures against DFA or DPA, or by their application to specific implementations