32 research outputs found

    A Synergetic Pattern Matching Method Based-on DHT Structure for Intrusion Detection in Large-scale Network

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    AbstractResearch in network security, with the attacks becoming more frequent, increasing complexity means, for the large-scale network intrusion detection, this paper presents a warning by analyzing the behavior of the log, the contents of the relevant association, through the DHT(Distributed Hash Table) distributed architecture, the Collabarative matching, fusion, and ultimately determine the method of attack paths. First, by improving the classical Apriori algorithm, greatly improving the efficiency of the association. At the same time, through the behavior pattern matching algorithms to extract information about the behavior of the alert and the behavior sequence elements to match the template, and through the right path to finally determine the value of the threat of the network path. After the design of a DHT network, the distributed collaborative match the path used to find complex network attacks. Finally, the overall algorithm flow, proposed a complete threat detection system architecture

    Roll-to-Roll Manufacturing of Robust Superhydrophobic Coating on Metallic Engineering Materials

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    Creating a robust superhydrophobic surface on the conventional engineering materials at mass production is of great importance for self–cleaning, anti–icing, non–wetting surface and low flow resistance in industrial applications. Herein, we report a roll–to–roll strategy to create durable and robust superhydrophobic surfaces with designed micro–/nano– scale hierarchical structures on many conventional engineering materials by combining electrical discharge machining, coating of carbon nanoparticles, and followed by oil penetration and drying. The treated surface shows good superhydrophobic properties with static water contact angle of 170±2o and slide angle of 3±1o. The treated surface also exhibits good resilience and maintains the performance after tested in various harsh conditions including water flushing for several days, sand abrasion, scratching with sandpapers and corrosive solution. Significantly, the superhydrophobic surfaces also shows a high efficiency of self–cleaning properties even after oil–contamination during applications

    Tunable electronic properties of graphene through controlling bonding configurations of doped nitrogen atoms

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    Single–layer and mono–component doped graphene is a crucial platform for a better understanding of the relationship between its intrinsic electronic properties and atomic bonding configurations. Large–scale doped graphene films dominated with graphitic nitrogen (GG) or pyrrolic nitrogen (PG) were synthesized on Cu foils via a free radical reaction at growth temperatures of 230–300 °C and 400–600 °C, respectively. The bonding configurations of N atoms in the graphene lattices were controlled through reaction temperature, and characterized using Raman spectroscopy, X–ray photoelectron spectroscopy and scanning tunneling microscope. The GG exhibited a strong n–type doping behavior, whereas the PG showed a weak n–type doping behavior. Electron mobilities of the GG and PG were in the range of 80.1–340 cm2 V−1·s−1 and 59.3–160.6 cm2 V−1·s−1, respectively. The enhanced doping effect caused by graphitic nitrogen in the GG produced an asymmetry electron–hole transport characteristic, indicating that the long–range scattering (ionized impurities) plays an important role in determining the carrier transport behavior. Analysis of temperature dependent conductance showed that the carrier transport mechanism in the GG was thermal excitation, whereas that in the PG, was a combination of thermal excitation and variable range hopping

    Short-Observation Measurement of Multiple Sinusoids With Multichannel Sub-Nyquist Sampling

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    Host Plants Identification for Adult Agrotis ipsilon, a Long-Distance Migratory Insect

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    In this study, we determined the host relationship of Agrotis ipsilon moths by identifying pollen species adhering them during their long-distance migration. Pollen carried by A. ipsilon moths was collected from 2012 to 2014 on a small island in the center of the Bohai Strait, which is a seasonal migration pathway of this pest species. Genomic DNA of single pollen grains was amplified by using whole genome amplification technology, and a portion of the chloroplast rbcL sequence was then amplified from this material. Pollen species were identified by a combination of DNA barcoding and pollen morphology. We found 28 species of pollen from 18 families on the tested moths, mainly from Angiosperm, Dicotyledoneae. From this, we were able to determine that these moths visit woody plants more than herbaceous plants that they carry more pollen in the early and late stages of the migration season, and that the amounts of pollen transportation were related to moth sex, moth body part, and plant species. In general, 31% of female and 26% of male moths were found to be carrying pollen. Amounts of pollen on the proboscis was higher for female than male moths, while the reverse was true for pollen loads on the antennae. This work provides a new approach to study the interactions between noctuid moth and their host plants. Identification of plant hosts for adult moths furthers understanding of the coevolution processes between moths and their host plants

    Experimental and Numerical Studies on Permeability Properties of Thermal Damaged Red Sandstone under Different Confining Pressures

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    The stability and safety of underground rock mass engineering are closely related to the permeability process of fluids and permeability properties of rocks. To reveal the flow behavior of fluid in thermal damaged rock, first, a rock seepage testing system was applied to study the permeability properties of red sandstone specimens after different high-temperature treatments from 200 to 800°C under different confining pressures of 10 to 30 MPa. Meanwhile, the microstructures of the red sandstone specimens were characterized by the mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). Then, the permeability process of pore water pressure and the flow form of fluid also were investigated by the numerical modeling method. The results show that the permeability properties of red sandstone specimens after high-temperature exposure follow linear Darcy’s law, and the relation between confining pressures and equivalent permeability coefficient (K0 ) can be described by a power function. Besides, the phenomenon that microscopic structural deterioration is intensified with increasing temperature and the average pore size and porosity of the red sandstone specimens are both power functions is related to the equivalent permeability coefficient. Furthermore, the results of numerical modeling indicated that the flow field within the range affected by confining pressures gradually becomes stable and orderly from disorder, and flow lines of the fluid become smooth and straight, and perpendicular to the isosurface of pore water pressure as time goes by. Moreover, the nonlinear correlation between pore water pressure and seepage path length changes to a linear correlation, which is consistent with linear Darcy’s law

    Electronic Properties of Microscale Reduced Graphene Oxide Patterned by Micromolding

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    Highly uniform reduced graphene oxide (rGO) array patterns with both stripe and square shapes have been fabricated on various substrates using PDMS based soft lithography. Morphology, structure and electrical properties of the GO patterns before and after annealing at 800 °C in H2 atmosphere were investigated. The conductivity and carriers mobilities of the rGO patterns were improved by four orders after H2-reduction. Temperature-dependent electrical measurements showed that charge transport occurs via a variable range hopping mechanism

    Chi-square test and Student’s t-test for pollen deposition frequencies of <i>Mythimna separata</i>.

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    <p>Chi-square test and Student’s t-test for pollen deposition frequencies of <i>Mythimna separata</i>.</p

    Frequencies of pollen deposition on migratory <i>Mythimna separata</i> near the Bohai Sea area in different migration stages during 2013–2015.

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    <p>Bars sharing the same letter mean that there were no significant differences at the 5% level by Tukey’s HSD tests.</p

    Identification of host plant use of adults of a long–distance migratory insect, <i>Mythimna separata</i> - Fig 2

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    <p>(A) Frequencies of pollen deposition on female and male proboscises, antennae and the total (proboscis and antennae) of <i>Mythimna separata</i> moths; (B) Frequencies of pollen deposition on the proboscis and antennae of female, male and total (female and male) <i>M</i>. <i>separata</i> moths. Single asterisk (*) or double asterisks (**) indicates that there was significant difference at the 1% or 5% level as determined by a Student’s t-test, and ns indicates that there was no significant difference.</p
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