Computer modelling of porous silicon formation

Porous silicon formation has been simulated by the finite diffusion length (FDL) model. This considers a dynamic isoconcentration profile from which the aggregating particles begin their random walks. In this paper we report on the isoconcentration profile non-uniformities which increase as the finite diffusion length is increased. The implementation of the FDL model with zero diffusion length generates non-fractal structures with a fractal dimension close to 1. It is found that Eden clusters cannot be generated at zero diffusion length, due to the problem of sinking isoconcentration profile. We conclude that these are limitations that should be considered in the FDL model for improving the understanding of physical phenomena such as formation and morphology of porous silicon.     

Layered Approach Using Conditional Random Fields for Intrusion Detection

Intrusion detection faces a number of challenges; an intrusion detection system must reliably detect malicious activities in a network and must perform efficiently to cope with the large amount of network traffic. In this paper, we address these two issues of Accuracy and Efficiency using Conditional Random Fields and Layered Approach. We demonstrate that high attack detection accuracy can be achieved by using Conditional Random Fields and high efficiency by implementing the Layered Approach. Experimental results on the benchmark KDD '99 intrusion data set show that our proposed system based on Layered Conditional Random Fields outperforms other well-known methods such as the decision trees and the naive Bayes. The improvement in attack detection accuracy is very high, particularly, for the U2R attacks (34.8 percent improvement) and the R2L attacks (34.5 percent improvement). Statistical Tests also demonstrate higher confidence in detection accuracy for our method. Finally, we show that our system is robust and is able to handle noisy data without compromising performance.     

DeepKnuckle: revealing the human identity

Multimedia Tools and Applications - Identification and authentication are ubiquitous questions which pan across various systems. In certain domains, they are of paramount importance. Like, security...     

Conductometric Study of Some Metal Halides in Glycerol + Water Mixtures

Electrolytic conductivities of potassium halides, KX (X = Cl⁻, Br⁻, I⁻) have been investigated in 10, 20, and 30 mass% glycerol + H₂O mixtures at 298.0, 308.0, and 318.0 K. The conductance data have been analyzed by the Fuoss-conductance–concentration equation in terms of the limiting molar conductance (Λ⁰), the association constant (K _A ), and the distance of closest approach of ion (R). The association constant (K _A ) tends to increase in the order: 10 mass% < 20 mass% < 30 mass% glycerol + water mixtures, while it decreases with temperature. Thermodynamic parameters ΔH ⁰, ΔG ⁰, and ΔS ⁰ are obtained and discussed. Also, Walden products (Λ⁰η) are reported. The results have been interpreted in terms of ion–solvent interactions and structural changes in the mixed solvents.     

Globally linearized control on diabatic continuous stirred tank reactor: a case study

This paper focuses on the promise of globally linearized control (GLC) structure in the realm of strongly nonlinear reactor system control. The proposed nonlinear control strategy is comprised of: (i) an input-output linearizing state feedback law (transformer), (ii) a state observer, and (iii) an external linear controller. The synthesis of discrete-time GLC controller for single-input single-output diabatic continuous stirred tank reactor (DCSTR) has been studied first, followed by the synthesis of feedforward/feedback controller for the same reactor having dead time in process as well as in disturbance. Subsequently, the multivariable GLC structure has been designed and then applied on multi-input multi-output DCSTR system. The simulation study shows high quality performance of the derived nonlinear controllers. The better-performed GLC in conjunction with reduced-order observer has been compared with the conventional proportional integral controller on the example reactor and superior performance has been achieved by the proposed GLC control scheme.     

An ultra-low power high-performance CMOS temperature sensor with an inaccuracy of − 0.3 °C/ + 0.1 °C for aerospace applications

Microsystem Technologies - In the current paper, a new temperature sensor with improved temperature inaccuracy and with very low power consumption has been designed for avionic industry. The...     

Evaluation of the effect of heat input in superduplex stainless steel deposition by the plasma powder process*

Plasma powder surfacing is one of the latest processes for application of coatings, with control of dilution as its main feature. Surfacing with superduplex stainless steels is an interesting option for the construction and repair of equipment for applications in a highly corrosive environment, allowing the desired characteristics to be achieved: corrosion resistance and good mechanical properties. The aim of this work is to assess the ferrite content in the weld metal and the mechanical characteristics via microhardness profiles in surfacing of C-Mn steel pipes with deposition of UNS S32760 by plasma powder surfacing. Welding operations were carried out on pipes with deposition of SDSS, employing three welding heat input levels, varying the welding speed or the welding current. Then the geometry was analysed, the ferrite content in the weld metal was quantified and the microhardness profile was recorded. Variation in welding heat input caused changes in weld bead geometry, with variation in the welding current producing the most significant changes. Increase in heat input caused decrease in ferrite content of the weld metal. Regarding microhardness, only the condition with a higher level of welding current gave sufficiently high levels of microhardness in the weld metal.     

Determination of satellite nadir and azimuth angles for a tilting sensor

The procedure for the determination of satellite nadir and azimuth angles has beenverifiedusing the Coastal Zone Color Scanner (CZCS) geolocation algorithm formulated by Wilson and co-workers in 1981. The error involved in the determination of satellite nadir and azimuth angles for positive and negative tilt of the mirror using the above method is discussed. A simple method to determine nadir and azimuth angles for a tilting mirror is proposed. The nadir and azimuth angles after roll, pitch and yaw of the satellite are presented.