基于支持向量数据描述的报警融合方法

报警融合是入侵检测系统中很重要的一个环节,然而不同的攻击类型具有不同的数据特点,统一的无差别的处理方法势必会存在缺陷。提出了采用基于支持向量数据描述的报警融合算法,并且结合模拟退火的思想,根据不同的攻击类型,选择适合它的属性和核参数,剔除冗余特征,避免样本不均衡产生的影响,通过局部检测、数据融合以及最终的决策分析,提高了报警的检测率,降低了漏报率。通过KDD99数据集对提出的方法进行了验证。     

Characteristics of DC magnetron sputtered ternary cobalt-nickel silicide thin films for ultra shallow junction devices

Ternary cobalt-nickel silicide thin films were synthesized by DC magnetron sputtering from an equiatomic cobalt-nickel alloy target. Grazing incidence XRD, Rutherford back scattering, high-resolution cross-sectional TEM analysis and electrical study were carried out to investigate the formation of silicide, stoichiometry, film thickness, depth profile and sheet resistance of as-deposited and post-deposition annealed films. The ternary silicide layer thickness was calculated from RBS simulated data, which was found to vary 20-43 nm for as-deposited and different vacuum annealed films. A minimum value of sheet resistance 2.73 Ω/sq corresponding to a resistivity of ∼8.4 μΩ-cm was obtained for optimized deposition and annealing conditions.     

Phase Transformation and Carbide Precipitation of Functional Gradient Semi-solid 9Cr18 Steel

The unique phase transformation and carbide evolution in 9Cr18 steel were investigated during semi-solid forming and subsequent heat treatment. The functional gradient thixoforging 9Cr18 component was divided into inner area and edge area. Microstructure evolution was different at each area. After semi-solid cooling, the solid particles in the inner area were retained as meta-austenite. During annealing, M_(23)C_6 carbide began to precipitate when temperature reached 700 °C.Martensite transformation occurred when temperature reached 800 °C. The occurrence of M_(23)C_6 carbide and martensite structure would be harmful to the mechanical properties of inner area. In the edge area, the liquid underwent eutectic transformation to form bar-shape M_7C_3 carbide and secondary austenite after semi-solid cooling. The width of bar-shape carbide would decrease during annealing. By controlling the carbide evolution, we could tailor the functional gradient material with required property.     

Effects of Annealing Temperature on the Structural,Optical,and Electrical Properties of ZnO Thin Films Grown on n-Si<100>Substrates by the Sol–Gel Spin Coating Method

The effects of annealing temperature on the sol–gel-derived ZnO thin films deposited on n-Sh100 i substrates by sol–gel spin coating method have been studied in this paper.The structural,optical,and electrical properties of ZnO thin films annealed at 450,550,and 650 °C in the Ar gas atmosphere have been investigated in a systematic way.The XRD analysis shows a polycrystalline nature of the films at all three annealing temperatures.Further,the crystallite size is observed to be increased with the annealing temperature,whereas the positions of various peaks in the XRD spectra are found to be red-shifted with the temperature.The surface morphology studied through the scanning electron microscopy measurements shows a uniform distribution of ZnO nanoparticles over the entire Si substrates of enhanced grain sizes with the annealing temperature.Optical properties investigated by photoluminescence spectroscopy shows an optical band gap varying in the range of 3.28–3.15 eV as annealing temperature is increased from 450 to 650 °C,respectively.The fourpoint probe measurement shows a decrease in resistivity from 2:1 10 2to 8:1 10 4X cm with the increased temperature from 450 to 650 °C.The study could be useful for studying the sol–gel-derived ZnO thin film-based devices for various electronic,optoelectronic,and gas sensing applications.     

On-line batch process monitoring using batch dynamic kernel principal component analysis

In this paper, a new dynamic and nonlinear batch process monitoring method, referred to as BDKPCA, is developed for on-line batch process monitoring, tactfully integrating kernel PCA and ARMAX time series model through estimating the Average Kernel Matrix (AKM) of all batch runs. AKM is an average of I, the batch number, Single-Batch Kernel Matrixes (SBKM). Each of the I SBKM is also an average of I kernel matrixes for each batch. The AKM contains the information of the stochastic variations and deviations among batches. This information will be very useful for the BDKPCA model to characterize the batch process in detail. The structure of BDKPCA model is very simple, and BDKPCA calculates the Hotelling's T² statistic and the Q-statistic for every time point, enhancing the method's sensitivity to the faults. Two cases are used to investigate the potential application of the proposed method, and its application to on-line batch process monitoring shows better performance than MKPCA.     

钻孔灌注桩首批混凝土灌注量之实用计算

为避免钻孔灌注桩因首批混凝土灌注量不足而导致水或泥浆进入导管，影响灌注桩的质量，按《公路桥涵施工技术规范》中公式计算的首批混凝土灌注量应乘以扩孔系数。     

A continuous photocatalysis system in the degradation of herbicide

The performance of both batch and continuous photo-catalytic reactors was studied to evaluate their capabilities in removing the sulfonyl urea herbicide of metsulfuron methyl (MM). It was found in a batch reactor that the addition of a small amount of powder activated carbon (PAC) significantly increased the rate of degradation of MM. The continuous photo-catalytic system resulted in 57% of MM removal. When a small dose of activated carbon was added in the photo-catalytic system, MM removal increased to 78–86% MM removal for retention times between of 5.25–21 min (corresponding to withdrawal rates of 10–40 mLmin⁻¹). In this study, the pseudo first order rate constants of a continuous photo-catalytic system revealed that shorter retention times were associated with lower rate constants. Solid phase micro extraction/gas chromatography (SPME/GC) results showed that high concentrations of MM were broken down to small volatile organic compounds (VOCs) by photo-catalytic oxidation. PAC adsorbed the photo-products and increased the degradation of MM.     

Mechanical behavior and microstructural evolution upon annealing of the accumulative roll-bonding (ARB) processed Al alloy 1100

The results of mechanical testing on ultra-fine grained aluminum processed by accumulative roll-bonding (ARB) were analyzed with TEM observation and in accordance of the microstructural evolution upon annealing. It was found that rapid grain growth, with the corresponding decrease in strength, did not occur until the annealing temperature of 200 °C or higher. The oxide rolled into the material near the bonding interfaces was seen to act as an obstruction for grain boundary migration across said interfaces. More interestingly, the strain near the interface due to the surface preparation technique used during ARB was found to form discontinuous segregates consisting of smaller grains formed during annealing or even ARB processing of higher number of cycles. Such phenomenon is attributed to recovery or polygonization due to the strain incurred. This study has also demonstrated that yield point phenomenon may be observed in a commercially pure fcc metal when the grain size is within a certain range.     

Assessment of the thermal stability of anodic alumina membranes at high temperatures

The thermal stability of anodic alumina membranes (AAMs) annealed in air from 750 °C up to 1100 °C was investigated. AAMs were produced by single-step anodising of laminated AA1050 in 0.30 M oxalic acid medium. The barrier layer provided thermal stability to the membranes, since it avoided or minimized bending and cracking phenomena. X-ray diffraction (XRD) analyses revealed that as-synthesized AAMs were amorphous and converted to polycrystalline after heat-treating above 750 °C. However, porous and barrier layers did not re-crystallize in the same way. The porous layer mainly crystallized in the γ-Al₂O₃ phase within the range of 900–1100 °C, while the barrier layer was converted to the α-Al₂O₃ phase at 1100 °C. Different grain sizes were also estimated from Scherrer's formula. Scanning electron microscopy (SEM) images pointed out that cell wall dilation of the porous layer explained membrane cracking, which was avoided in presence of the barrier layer.     

Prediction of H2 Content and Inert Gas Circulation Rate Effects on Batch Annealing Process

Steel strip coils need to be annealed after they leave the cold-rolling process. The purpose of annealing is to improve steel strip formability and to remove residual internal stresses imparted during rolling. Simultaneous increase of circulation rate and inert gas hydrogen content may have considerable effects on reducing the annealing process time. A mathematical model was developed to obtain a more accurate evaluation of the effects of these two parameters on heating and cooling cycles in the annealing process. The results from the simulation of an ordinary annealing process by the proposed model were compared with values measured at site and the accuracy of the model was confirmed. Finally, the effects of increasing hydrogen content and circulation rate were investigated, first independently from each other and then simultaneously. The predictions by the model showed that reduction of annealing time would be considerable when both parameters were simultaneously increased.