Toward a blockchain-based framework for challenge-based collaborative intrusion detection

International Journal of Information Security - Network intrusions are a big threat to network and system assets, which have become more complex to date. To enhance the detection performance,...     

Application of Strong Fluctuation Random Medium Theory to Scattering from Vegetation-Like Half Space

A model for vegetation scatter is developed using the theory of electromagnetic wave propagation in random medium with strong permittivity fluctuations. In applying the strong fluctuation theory, the singularity of the dyadic Green's function is taken into account. Backscattering coefficients are computed using the distorted Born approximation and illustrated as a function of incidence angle, frequency and moisture content of the vegetation. The mixing formula of the de Loor [28] was used in estimating the permittivity of leaves. The correlation function of Fung and Fung [18], and Fung and Ulaby [19] is used for the random medium.     

Creep and shrinkage analysis of reinforced concrete frames by history‐adjusted and shrinkage‐adjusted elasticity moduli

Consideration of the time‐dependent deformations due to creep and shrinkage is often necessary to ensure satisfactory behavior of complex concrete structures. The stresses and deformations of a reinforced concrete frame can be analyzed by the finite element method using time integration. However, as the full stress history prior to each time interval considered is necessary, with the increase in the number of time intervals used, the amount of computations increases dramatically. The concept of age‐adjusted elasticity modulus is further explored to develop new functions for efficient evaluation of time‐dependent behavior of concrete frames. The history‐adjusted elasticity modulus is devised so that stage construction can be modeled more accurately. Likewise, the shrinkage‐adjusted elasticity modulus is introduced to enable shrinkage analysis to be carried out using one single step. The methods can cope with frame structures built and loaded in several stages. Accurate results can be obtained by considering just a few large time intervals instead of those fine time steps used in time integration. Numerical examples are presented to demonstrate the usefulness of the new methods. Copyright © 2007 John Wiley & Sons, Ltd.     

Biomonitoring using accessible human cells for exposure and health risk assessment

We describe a nonradioactive preembedding in situ hybridization protocol using digoxigenin-labeled RNA probes and tyramide signal amplification to increase the sensitivity of detection. The protocol is sensitive enough for electron microscopic localization of endogenous messenger RNAs encoding beta-actin and amphoterin. Three visualization methods were compared: diaminobenzidine enhanced by nickel, Nanogold enhanced by silver and gold toning, and fluorescently labeled tyramides. Diaminobenzidine and Nanogold can be used in both light and electron microscopy. The nickel-enhanced diaminobenzidine was the most sensitive visualization method. It is easy to accomplish but a drawback is poor spatial resolution, which restricts its use at high magnifications. Nanogold visualization has considerably better spatial resolution and is therefore recommended for electron microscopy. Fluorescent tyramides, especially TRITC-tyramide, offer a good detection method for fluorescence and confocal microscopy. The methods were used to localize amphoterin and beta-actin mRNAs in motile cells. Both mRNAs were found in the soma and cell processes. In double labeling experiments, beta-actin mRNA localized to filamentous structures that also contained ribosomal proteins. Especially in the cortical cytoplasm, beta-actin mRNA was associated with actin filaments. Direct localization to microtubules was only rarely seen. (J Histochem Cytochem 47:99-112, 1999)     

Process Capability Improvement for Multistage Processes

While the quality control procedures for multistage has been considerably studied, multistage process capability analysis has not been explored much at all. Fostering on the recent development of the multistage process variation transmission model, a multistage process capability analysis algorithm is developed to prioritize process improvement efforts. The application of algorithm is demonstrated with two 2-stage industrial process examples and a 4-stage process example for its expandability.     

Evaluations of P/M Gamma Titanium Aluminides

For the last five years, the Structures, Materials and Propulsion Laboratory of the Institute for Aerospace Research, National Research Council of Canada, has devoted a significant amount of effort investigating powder metallurgy gamma titanium aluminides. The main results of the studies on microstructural evolution, hot workability, creep behaviour and microstructure-mechanical property relationships for P/M gamma alloys are reviewed in this article. Work is in progress to apply the knowledge gained to cast gamma alloys for gas turbine applications.     

NO Reduction with Hydrogen over Cobalt Molybdenum Nitride and Molybdenum Nitride: A Comparison Study

Cobalt molybdenum nitride (Co₃Mo₃N) and molybdenum nitride (Mo₂N) were investigated for the catalytic reduction of NO with H₂. The latter deactivated rapidly with time on stream, whereas the former remained active and stable over a test period of 30 h. The results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and H₂-temprature-programmed reduction (H₂-TPR) characterization indicated that the deactivation of Mo₂N was due to the bulk oxidation of Mo₂N to MoO₂. As for the Co₃Mo₃N catalyst, despite partial decomposition into Mo₂N and Co, it remained resistant to oxidation. The results suggest that compared to the monometallic nitride, the bimetallic one is more suitable for NO reduction with H₂.     

Preparation,characterization and photocatalytic activity of Bi2O3–MgO composites

A series of Bi₂O₃–MgO composites were synthesized by solvent-thermal method. It was found that the Bi₂O₃–MgO composites perform much better than TiO₂ (P25), Bi₂O₃ and MgO in the photocatalytic degradation of rhodamine B (RhB) in the presence of HCl and under irradiation of visible light (λ > 400 nm). The effects of Bi/Mg molar ratio, crystallization temperature of Bi₂O₃–MgO and reaction conditions on photocatalytic activity were studied. The best performance was observed over the composite with Bi:Mg molar ratio equal to 2:1 that had been subject to crystallization at 120 °C for 20 h. In addition, the photocatalytic efficiency of the composite can be significantly enhanced by the presence of hydrochloric acid. The prepared samples were characterized by XRD and UV–vis DRS techniques. The relationships between the structure and photocatalytic performance of the as-prepared Bi₂O₃–MgO samples were also investigated.