基于最小能量法的无线传感器网络节点能量有效性研究

分析了传统无线网络系统模型中的能耗.利用最小能量编码（ME-Coding）作为信源编码的On/Off Keying(OOK)调制方法,对节点间传输的信号序列进行了优化,结果提高了信噪比,降低了误码率.但实验模拟仿真结果表明,当将链路能耗考虑进总体能量消耗中后,若使用传统系统模型,其总能耗并未得到优化. 因此提出并验证了更加适合最小能量法的系统模型,以便降低系统能耗和延长传感器网络节点的寿命.     

A method for single image restoration based on the principal ergodic

We present a method to extract from a single image both object and point spread function using low contrast features of an extended field of view. Invoking the principal ergodic on stochastic turbulent phenomena, we show that the aberration parameters, characteristics of the earth's turbulence, can be recovered from multiple features within an isoplanatic patch. The ensemble statistics is replacing the spatial statistics of a single realization to derive an equivalent modulation transfer function and to apply usual deconvolution techniques such as Richardson-Lucy algorithms. The reliability of this postprocessing treatment has been tested on synthetic data, on solar granulation observations performed at La Lunette Jean Rosch du Pic du Midi, and during the event of the Venus transit at La Tour Solaire de Meudon.     

Experimental investigation of bearing slip in a wind turbine gearbox during a transient grid loss event

This work investigates the behaviour of the high‐speed stage of a wind turbine gearbox during a transient grid loss event. Dynamometer testing on a full‐scale wind turbine nacelle is used. A combination of external and internal gearbox measurements are analysed. Particular focus is on the characterization of the high‐speed shaft tapered roller bearing slip behaviour. This slipping behaviour is linked to dynamic events by many researchers and described as a potential bearing failure initiator; however, only limited full‐scale dynamic testing is documented. Strain gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing behaviour in detail. It is shown that during the transient event the high‐speed shaft experiences a combined torsional and bending deformation. These unfavourable loading conditions induce roller slip in the bearings during the torque reversals, indicating the potential of the applied load case to go beyond the preload of the tapered roller bearing. Copyright © 2016 John Wiley & Sons, Ltd.     

The effect of surface energy, adsorbed RGD peptides and fibronectin on the attachment and spreading of cells on multiwalled carbon nanotube papers

We report that hydrophilic oxidized multiwalled carbon nanotube papers (CNPs) were efficient substrates for attachment, spreading, and proliferation of MG-63 cells. Complete spreading occurred in the first 4 h of culture even without complete serum or pre-adsorbed adhesion proteins such as collagen or fibronectin. By contrast, the density of adherent cell on hydrophobic CNPs was low. Spreading did not happen after 24 h of culture in absence of serum proteins and growth factors on such papers. Cell viability concomitantly decreased. We also observed that a short RGD peptide, designed to adsorb on both hydrophobic and hydrophilic CNPs, enhanced adhesion, spreading, and proliferation only on hydrophilic CNPs. By contrast, adsorbed fibronectin triggers cell adhesion and spreading on both types of CNPs. Our results show that the imitation of tissue basal membranes with the nanofibrous structure of CNPs is insufficient to trigger the proliferation and spread of cells. Chemical cues are also needed for cells to spread. CNPs, however, offer a better substrate for adhesion protein absorption than do non-porous polymers.     

Effects of geographic source, rearing system, and season on the nutritional quality of wild and farmed Perca fluviatilis

The effects of season, geographic source (Lake Geneva, Rhine River), and rearing system (extensive, semiextensive, and intensive systems) on the lipid content and FA composition of fillets of Perca fluviatilis were studied. Significant differences in the total lipid content were found between fish coming from the Rhine River and Lake Geneva (1.21 and 1.48%, respectively). Seasonal effects were investigated quarterly for perch sampled in the Rhine River. Intensively reared perch displayed a higher lipid content (1.48%) than the other farmed perch, i.e., 1.26% for a semiextensive system and 1.16% for an extensive system. No significant difference in lipid content was found (i) between lacustrine fish and intensively reared fish or (ii) among fish from the Rhine River and the semiextensive or extensive rearing systems. The main FA were 22∶6n−3 (DHA, 21.3–37.1% of total FA), 16∶0 (17.7–20.2%), 20∶5n−3 (EPA, 9.2–13.2%), 18∶1 (8.0–11.5%), 20∶4n−6 [arachidonic acid (ARA), 1.9–10.7%], 16∶1 (4.3–6.0%), and 18∶2n−6 (2.1–6.0%). In comparison with perch coming from the Rhine River, the lacustrine fish were characterized by higher total n−6 PUFA and a lower proportion of both total monounsaturated FA (MUFA) and total n−3 PUFA. Among rearing systems, extensively farmed fish had higher n−6 PUFA and lower n−3 PUFA contents. Wild fish showed higher ARA and 18∶2n−6 than farmed fish. They also had significantly more EPA (12.5–13.2%) than farmed perch (9.2–10.9%). For DHA no difference existed between (i) the lacustrine fish (31.9% of total FA) and the intensively reared fish (33.0%) and (ii) the Rhine (37.1%) and semiextensively reared fish (36%). Effects of size, diet composition, and environmental conditions on the total lipid contents and FA composition are discussed.     

An overview and experimental analysis of furniture fire safety regulations in Europe

The regulation requirements for upholstered furniture are nationally defined and lead to very different safety levels across Europe. This paper studies the fire performance of upholstered furniture across Europe and demonstrates the differences in the fire safety of sofas in different countries. Real sofas were purchased over Europe and tested first alone then for several of them in a room scenario. The fire performance of such upholstered furniture is related to their constitution and possibly to the improvement of their performance by physical and/or chemical means. Results are presented from a performance point of view and not focusing on the different technical solutions that can be envisaged, such as fire barriers or flame retardants. The results clearly show the effect of stricter regulations, not necessarily on the maximum heat release but mainly on the time available to escape, which is critical in many fire scenarios. Such regulations may have a positive effect, but they have to be performance-based, evaluated properly, and implemented considering market surveillance.     

Hybrid atomistic�Ccontinuum simulations of fluid flows involving interfaces

In this work, we use an hybrid atomistic–continuum (HAC) simulation method to study transient and steady isothermal flows of Lennard-Jones fluids near interfaces. Our hybrid method is based on a domain decomposition algorithm. The flow domain is composed of two overlapping regions: an atomistic region described by molecular dynamics, and a continuum region described by a finite volume discretization of the incompressible Navier–Stokes equations. To show the interest of such an hybrid method to compute flows near fluid/solid interface, we first applied our hybrid scheme to the classical Couette flow, where the moving wall is modelled at the atomistic scale. In addition, we also studied an oscillatory shear flow. Then, to compute flows near fluid/fluid interface, we applied our method to a two-phase Couette flow (liquid/gas), where the interface is modelled at the molecular scale. We show that hybrid results can sometimes differ from those provided by analytical solutions deduced from continuum mechanics equations combined with usual boundary/interface relations. For the Couette and oscillatory shear flows, a good agreement is found between hybrid simulations and macroscopic analytical solutions, however, we noticed that the fluid in contact with the wall can be more entailed than what expected. For the liquid/gas Couette flow, the hybrid simulation exhibits an unexpected jump of the velocity in the interfacial region, corresponding to a partial slip between the two fluid phases. Those interesting results highlight the interest of using an HAC method to deal with systems for which surfaces/interfaces effects are important.     

Architecture of a morphological malware detector

Most of malware detectors are based on syntactic signatures that identify known malicious programs. Up to now this architecture has been sufficiently efficient to overcome most of malware attacks. Nevertheless, the complexity of malicious codes still increase. As a result the time required to reverse engineer malicious programs and to forge new signatures is increasingly longer. This study proposes an efficient construction of a morphological malware detector, that is a detector which associates syntactic and semantic analysis. It aims at facilitating the task of malware analysts providing some abstraction on the signature representation which is based on control flow graphs. We build an efficient signature matching engine over tree automata techniques. Moreover we describe a generic graph rewriting engine in order to deal with classic mutations techniques. Finally, we provide a preliminary evaluation of the strategy detection carrying out experiments on a malware collection.     

Identification of New Purpuroine Analogues from the Arctic Echinodermata Pteraster militaris That Inhibit FLT3-ITD+ AML Cell Lines

Isolation of bioactive products from the marine environment is considered a very promising approach to identify new compounds that can be used for further drug development. In this work we have isolated three new compounds from the purpuroine family by mass-guided preparative HPLC; purpuroine K-M. These compounds where screened for antibacterial- and antifungal activity, antibiofilm formation and anti-cell proliferation activity. Additionally, apoptosis-, cell cycle-, kinase binding- and docking studies were performed to evaluate the mechanism-of-action. None of the compounds showed activity in antibacterial-, antibiofilm- or antifungal assays. However, one of the isolated compounds, purpuroine K, showed activity against two cell lines, MV-4-11 and MOLM-13, two AML cell lines both carrying the FTL3-ITD mutation. In MV-4-11 cells, purpuroine K was found to increase apoptosis and arrest cells cycle in G1/G0, which is a common feature of FLT3 inhibitors. Interactions between purpuroine K and the FLT3 wild type or FLT3 ITD mutant proteins could however not be elucidated in our kinase binding and docking studies. In conclusion, we have isolated three novel molecules, purpuroine K-M, one of which (purpuroine K) shows a potent activity against FLT3-ITD mutated AML cell lines, however, the molecular target(s) of purpuroine K still need to be further investigated.