Statistical Modeling and Analysis of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Conditions

Recently, mobile-to-mobile (M2M) cooperative network technology has gained considerable attention for its promise of enhanced system performance with increased mobility support. As this is a new research field, little is known about the statistical properties of M2M fading channels in cooperative networks. So far, M2M fading channels have mainly been modeled under the assumption of non-line-of-sight (NLOS) conditions. In this paper, we propose a new model for M2M fading channels in amplify-and-forward relay links, where it is assumed that a line-of-sight (LOS) component exists in the direct link between the source mobile station and the destination mobile station. Analytical expressions will be derived for the main statistical quantities of the channel envelope, such as the mean value, variance, probability density function (PDF), level-crossing rate (LCR), and average duration of fades (ADF) as well as the channel phase. Our results show that the statistical properties of the proposed M2M channel are quite different from those of double Rayleigh and double Rice channels. In addition, a high-performance channel simulator will be presented for the new M2M channel model. The developed channel simulator is used to confirm the correctness of all obtained theoretical results by simulations.     

Fabrication of cadmium titanate nanofibers via electrospinning technique

Here we present an electrospinning technique for the fabrication of cadmium titanate/polyvinyl-pyrrolidone composite nanofibers. The composite nanofibers are then annealed at 600 °C to obtain ilmenite rhombohedral phase cadmium titanate nanofibers. The structure, composition, thermal stability and optical properties of as synthesized and annealed cadmium titanate nanofibers are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and ultraviolet–visible spectroscopy. The average diameter and length of the nanofibers are found to be ～150–200 nm and ～100 μm, respectively.     

A new approach for image encryption and watermarking based on substitution box over the classes of chain rings

Multimedia Tools and Applications - The meanings of passing information from one side to other side by a conventional way is been changed because of internet and communication technology. The...     

Wavelets-based facial expression recognition using a bank of support vector machines

A human face does not play its role in the identification of an individual but also communicates useful information about a person’s emotional state at a particular time. No wonder automatic face expression recognition has become an area of great interest within the computer science, psychology, medicine, and human–computer interaction research communities. Various feature extraction techniques based on statistical to geometrical data have been used for recognition of expressions from static images as well as real-time videos. In this paper, we present a method for automatic recognition of facial expressions from face images by providing discrete wavelet transform features to a bank of seven parallel support vector machines (SVMs). Each SVM is trained to recognize a particular facial expression, so that it is most sensitive to that expression. Multi-classification is achieved by combining multiple SVMs performing binary classification using one-against-all approach. The outputs of all SVMs are combined using a maximum function. The classification efficiency is tested on static images from the publicly available Japanese Female Facial Expression database. The experiments using the proposed method demonstrate promising results.     

Fabrication of covalently bonded nanostructured thin films of epoxy resin and polydimethylsiloxane for oil adsorption

Thin films of architectures PEI(CNER_a/PDMS)_n, PEI(CNER_b/PDMS)_n, (PEI/CNER_b)_n and PEI(CNER_b/NH₂-MMT/PEI)_n have been fabricated via covalent layer-by-layer technique. Different film deposition parameters such as solvent type, polymer concentration, polymer ratio and dipping time have been optimized to achieve a uniform growth of layers. The effect of polymer concentration and dipping time on film thickness was also studied via ellipsometer. The optimized ratio of polymer concentration was 1:1 and 1:2 for PEI(CNER_a/PDMS)_n and PEI(CNER_b/PDMS)_n, respectively. AFM analysis indicated that the films were homogeneous while contact angle measurements revealed that although films were hydrophobic in nature yet they have wetting property due to the presence of hydroxyl groups formed during curing process. These epoxy-based multilayers have shown significant oil adsorption capacity. All the fabricated films qualify scotch tape test and were found resistant towards strong acids, bases and organic solvents.     

Novel vinyl-modified sepiolite-based polymer nanocomposites: synthesis and characterization

An environmental-friendly synthesis of polymer clay nanocomposites (PCNs) was carried out by incorporation of nanoclay into polymer matrix for their potential application as sorbent of metals present in aqueous media. Polyacrylonitrile was chemically grafted onto 77% vinyl triethoxysilane-modified sepiolite. The polymerization was carried out with benzoyl peroxide (BPO, C₁₄H₁₀O₄) initiator in three different weight ratios of 1.0, 2.0, and 3.0%. The maximum polymer grafting of about 83% was obtained in nanocomposite initiated by 2.0% ratio of BPO. The surface modification of nanocomposites was carried out using hydroxyl amine hydrochloride (NH₂OH·HCl). The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, thermogravimetric analysis, and Brunauer–Emmett–Teller technique. The copper removal tendency of nanocomposites was studied by atomic absorption spectroscopy. The maximum adsorption of copper was 86%, which could be achieved by nanocomposites synthesized with 2% initiator. The results have revealed the practical potential of the prepared PCN as efficient adsorbents.