Detecting DDoS Attacks in Cloud Computing Using Extreme Learning Machine and Adaptive Differential Evolution

Wireless Personal Communications - Distributed denial of service (DDoS) attacks disrupt the availability of cloud services. The detection of these attacks is a major challenge in the cloud...     

RETRACTED ARTICLE: Towards understanding polyhydroxyalkanoates and their use

It is fact that Polymers and their products have changed the face of the world in all the field of the technology. They are the future of the coming up generation of the research of the world. But this is also fact that these synthetic non biodegradable polymers have created a tough situation for the living being for a healthy life. Polyhydroxyalkanoates are polyesters produced by bacteria as intracellular storage materials in response to a variety of nutritional and environmental conditions, such as nitrogen limitation Polyhydroxyalkanoates (PHAs) are gaining increasing attention in the biodegradable polymer market due to their promising properties such as high biodegradability in different environments, not just in composting plants, and processing versatility. Indeed among biopolymers, these biogenic polyesters represent a potential sustainable replacement for fossil fuel-based thermoplastics. Most commercially available PHAs are obtained with pure microbial cultures grown on renewable feedstocks (i.e.glucose) under sterile conditions but recent research studies focus on the use of wastes as growth media.PHA can be extracted from the bacteria cell and then formulated and processed by extrusion for production of rigid and flexible plastic suitable not just for the most assessed medical applications but also considered for applications including packaging, moulded goods, paper coatings, non-oven fabrics, adhesives, films and performance additives. The present paper reviews the PHAs, their main properties, processing aspects, commercially available ones, as well as limitations and related improvements being researched,with specific focus on potential applications of PHAs in packaging.     

Earthworm coelomocytes as nanoscavenger of ZnO NPs

Earthworms can ‘biotransform’ or ‘biodegrade’ chemical contaminants, rendering them harmless in their bodies, and can bioaccumulate them in their tissues. They ‘absorb’ the dissolved chemicals through their moist ‘body wall’ due to the interstitial water and also ingest by ‘mouth’ while soil passes through the gut. Since the advent of the nanotechnology era, the environmental sink has been continuously receiving engineered nanomaterials as well as their derivatives. Our current understanding of the potential impact of nanomaterials and their natural scavenger is limited. In the present investigation, we studied the cellular uptake of ZnO nanoparticles (NPs) by coelomocytes especially by chloragocytes of Eisenia fetida and their role as nanoscavenger. Results from exposure to 100- and 50-nm ZnO NPs indicate that coelomocytes of the earthworm E. fetida show no significant DNA damage at a dose lower than 3 mg/l and have the potential ability to uptake ZnO NPs from the soil ecosystem and transform them into microparticles.     

Coexistence of interfacial stress and charge transfer in graphene oxide-based magnetic nanocomposites

In this paper, the existence of both compressive stress and charge transfer process in hydrothermally synthesized cobalt ferrite–graphene oxide (CoFe₂O₄/GO) nanocomposites has been established. Transmission electron microscopy results reveal the decoration of CoFe₂O₄ nanoparticles on GO sheets. Magnetic response of nanocomposites was confirmed from superconducting quantum interference device magnetometer measurement. Optical properties of these nanocomposites were investigated by Raman spectroscopy. The interfacial compressive stress involved in this system has been evaluated from observed blue shift of characteristic G peak of graphene oxide. Increase in the full-width half-maximum value as well as upshift in D and G peaks is clear indications of involvement of charge transfer process between GO sheets and dispersed magnetic nanoparticles. The effect of charge transfer process is quantified in terms of shifting of Fermi energy level of these nanocomposites. This is evaluated from variation in contact surface potential difference using scanning Kelvin probe microscopy. XRD spectra of CoFe₂O₄/GO confirm the polycrystalline nature of CoFe₂O₄ nanoparticles. Lattice strain estimated from XRD peaks is correlated with the observed Raman shift.     

Dual‐band circularly polarized dielectric resonator antenna for wireless applications

This letter investigates an integrated antenna configuration for WLAN/WiMAX applications. The proposed composite antenna configuration is simply the grouping of ring dielectric resonator along with reformed square‐shaped slot antenna. Three significant characteristics of proposed article are: (1) aperture act as magnetic dipole and excite HE_11δ mode in ring dielectric resonator antenna; (2) reforming of square aperture generates orthogonal modes in ring DRA and creates CP in lower frequency band; (3) annular‐shaped Microstrip line along with reformed square aperture creates CP wave in upper frequency band. With the purpose of certifying the simulated outcomes, prototype of proposed structure is fabricated and tested. Good settlement is to be got between experimental and software generated outcome. Experimental outcomes show that the proposed radiating structure is operating over 2 frequency bands that is, 2.88‐3.72 and 5.4‐5.95 GHz. Measured 3‐dB axial ratio bandwidth in lower and upper frequency band is approximately 9.52% (3.0‐3.4 GHz) and 5.85% (5.64‐5.98 GHz), respectively. These outcomes indicate that the proposed composite antenna structure is appropriate for WLAN and WiMAX applications.     

Buccoadhesive Tablets of Nifedipine: Standardization of A Novel Buccoadhesive-Erodible Carrier

Buccoadhesive tablets of nifedipine were obtained by incorporation of nifedipine in suitable carrier systems standardised based on bioadhesion and dissolution. The carrier systems were formulated using sodium alginate as the bioadhesive. Mannitol, lactose, polyethylene glycol 6000 and polyethylene glycol 4000 were incorporated as solubilisers, singly or in combination. Carrier systems having a diameter of 11 mm and weighing about 200 mg were obtained by standard tabletting techniques using polyvinylpyrolidone as the binder. The systems were evaluated for bioadhesion and dissolution, 'in vitro' and 'in vivo' in seven normal healthy human volunteers. Based on these studies, nifedipine (5 mg) was incorporated in selected carrier systems to obtain buccoadhesive tablets of nifedipine. These tablets exhibited rapid 'in vitro' drug release.     

Modified circular common element four‐port multiple‐input‐multiple‐output antenna using diagonal parasitic element

A four‐port multiple input multiple‐output (MIMO) antenna with common radiating element is proposed for 2.4 GHz Wi‐Fi applications. It comprises a modified circular radiator fed by four identical modified feedlines, partial ground planes, and a diagonal parasitic element (DPE). The parasitic element is used to enhance the interport isolation. The antenna has a 2:1 Voltage standing wave ratio (VSWR) impedance band 2.34‐2.56 GHz and nearly omnidirectional radiation patterns. The radiation efficiency is more than 79% and gain is 2 dBi at resonant 2.43 GHz. The isolation in the given frequency band is 10 dB. At the 2.43 GHz, the isolation between adjacent ports (1, 2 and 1, 4) is 14 dB and between opposite ports (1, 3) is 12 dB. The mean effective gain (MEG) ≤ ?2.7 dB and envelope correlation coefficient is <0.01. The ?10 dB total active reflection coefficient bandwidth is 202 MHz. The antenna is designed for a Wi‐Fi device and the effectiveness of antenna has been checked for distance of ½ feet from the human head. The specific absorption rate (SAR) is found to be ≤0.17 W/Kg by CST simulation tool.     

Ground observation of electromagnetic emissions related to clusters of earthquakes

Ultra-low frequency (ULF) and very low frequency (VLF) data obtained from three ground-based experiments at Agra station (latitude 27.2° N, longitude 78.0° E) in India, namely measurement of ULF magnetic field emissions using a three-component search coil magnetometer, the vertical component of VLF electric field emissions with a borehole antenna, and the phase and amplitude of fixed frequency VLF transmitter signals using an Absolute Phase and Amplitude Logger (AbsPAL) receiver, were analysed in search of possible precursors of two major seismic activities that occurred in Sumatra (Indonesia) during the post-tsunami period between January and April 2005. These two major seismic events occurred as clusters of earthquakes during 27–29 January and 28–30 March 2005. The results show that, apart from the borehole antenna, all the experiments showed precursors due to these clusters of earthquakes. Such precursors were not seen in the case of isolated large-magnitude earthquakes. Furthermore, the precursory duration was influenced by a magnetic storm that occurred about a week before the clusters. The mechanism of ULF propagation to long distances between Sumatra and Agra and perturbations in the ionosphere before the clusters are discussed.