Investigation of rectangular solid-core photonic crystal fiber as temperature sensor

Microsystem Technologies - In this article, a rectangular solid-core photonic crystal fiber (PCF) is proposed as temperature sensor. The air-holes of the PCF have been filled with Ethyl alcohol...     

A vision modeling framework for DHM using geometrically estimated FoV

Digital human modeling (DHM) involves modeling of structure, form and functional capabilities of human users for ergonomics simulation. This paper presents application of geometric procedures for investigating the characteristics of human visual capabilities which are particularly important in the context mentioned above. Using the cone of unrestricted directions through the pupil on a tessellated head model as the geometric interpretation of the clinical field-of-view (FoV), the results obtained are experimentally validated. Estimating the pupil movement for a given gaze direction using Listing’s Law, FoVs are re-computed. Significant variation of the FoV is observed with the variation in gaze direction. A novel cube-grid representation, which integrated the unit-cube representation of directions and the enhanced slice representation has been introduced for fast and exact point classification for point visibility analysis for a given FoV. Computation of containment frequency of every grid-cell for a given set of FoVs enabled determination of percentile-based FoV contours for estimating the visual performance of a given population. This is a new concept which makes visibility analysis more meaningful from ergonomics point-of-view. The algorithms are fast enough to support interactive analysis of reasonably complex scenes on a typical desktop computer.     

A blind audio watermarking based on singular value decomposition and quantization

International Journal of Speech Technology - In this work, we have proposed a robust audio watermarking technique in which a binary image is embedded into a host audio signal for copyright...     

On the polynomial solvability of distributionally robust k-sum optimization

In this paper, we define a distributionally robust k-sum optimization problem as the problem of finding a solution that minimizes the worst-case expected sum of up to the k largest costs of the elements in the solution. The costs are random with a joint probability distribution that is not completely specified but rather assumed to be known to lie in a set of probability distributions. For k=1, this reduces to a distributionally robust bottleneck optimization problem while for k=n, this reduces to distributionally robust minimum sum optimization problem. Our main result is that for a Fréchet class of discrete marginal distributions with finite support, the distributionally robust k-sum combinatorial optimization problem is solvable in polynomial time if the deterministic minimum sum problem is solvable in polynomial time. This extends the result of Punnen and Aneja [On k-sum optimization, Oper. Res. Lett. 18(5)(1996), pp. 233–236] from the deterministic to the robust case. We show that this choice of the set of distributions helps preserve the submodularity of the k-sum objective function which is an useful structural property for optimization problems.     

PRATIT: a CNN-based emotion recognition system using histogram equalization and data augmentation

Multimedia Tools and Applications - Emotions are spontaneous feelings that are accompanied by fluctuations in facial muscles, which leads to facial expressions. Categorization of these facial...     

Green Machining to Net Shape Alumina Ceramics Prepared Using Different Processing Routes

In the present study, the net shape manufacturing of alumina ceramics was carried out using computer numerically controlled (CNC) machining of differently processed alumina green bodies using different tool materials and geometries. In case of a carbide-coated tool, severe wear was observed; on the contrary, a diamond-coated tool was used successfully. The profile of the as-machined surface was found to be smooth using diamond-coated flat tool. Near net shape alumina was demonstrated using CNC green machining from optimized machining conditions. Optical micrograph and the surface roughness of the as-machined samples showed good surface finish for the green bodies with higher binder content.     

Synthesis of Nanocrystalline Alumina Using Egg White

A new simplified route to prepare nanocrystalline alumina powders is proposed. The method involved the use of freshly extracted egg white (ovalbumin) and aluminum nitrate in an aqueous medium. Changes in ionic strength upon addition of aluminum nitrate resulted in gelation of ovalbumin. The added metal ions were dispersed in the gelled ovalbumin matrix. Heat treatment of the gelled mass resulted in nanosized γ alumina at as low a temperature as 330°C. TEM analysis showed that the particle size ranged from 15 to 80 nm.     

Graphene-based environmental barriers

Many environmental technologies rely on containment by engineered barriers that inhibit the release or transport of toxicants. Graphene is a new, atomically thin, two-dimensional sheet material, whose aspect ratio, chemical resistance, flexibility, and impermeability make it a promising candidate for inclusion in a next generation of engineered barriers. Here we show that ultrathin graphene oxide (GO) films can serve as effective barriers for both liquid and vapor permeants. First, GO deposition on porous substrates is shown to block convective flow at much lower mass loadings than other carbon nanomaterials, and can achieve hydraulic conductivities of 5 × 10(-12) cm/s or lower. Second we show that ultrathin GO films of only 20-nm thickness coated on polyethylene films reduce their vapor permeability by 90% using elemental mercury as a model vapor toxicant. The barrier performance of GO in this thin-film configuration is much better than the Nielsen model limit, which describes ideal behavior of flake-like fillers uniformly imbedded in a polymer. The Hg barrier performance of GO films is found to be sensitive to residual water in the films, which is consistent with molecular dynamics (MD) simulations that show lateral diffusion of Hg atoms in graphene interlayer spaces that have been expanded by hydration.     

An image encryption scheme using sequence generated by interval bisection of polynomial function

Multimedia Tools and Applications - Chaos based image encryption techniques are well accepted in research communities to perform permutation at pixel/bit level using pseudo-random sequence and...