Transmission protocols in Cognitive Radio Mesh Networks

A Cognitive Radio (CR) is a radio that can adjust its transmission limit based on available spectrum in its operational surroundings. Cognitive Radio Network (CRN) is made up of both the licensed users and unlicensed users with CR enable and disabled radios. CR’S supports to access dynamic spectrum and supports secondary user to access underutilized spectrum efficiently, which was allocated to primary users. In CRN’S most of the research was done on spectrum allocation, spectrum sensing and spectrum sharing. In this literature, we present various Medium Access (MAC) protocols of CRN’S. This study would provide an excellent study of MAC strategies

Novel Approach for Control Data Theft Attack in Cloud Computing

Information security is a major problem faced by cloud computing around the world. Because of their adverse effects on organizational information systems, viruses, hackers, and attackers insiders can jeopardize organizations capabilities to pursue their undertaken effectively. Although technology based solutions help to mitigate some of the many problems of information security, even the preeminent technology can’t work successfully unless effective human computer communication occurs.IT experts, users and administrators all play crucial role to determine the behavior that occurs as people interact with information technology will support the maintenance of effective security or threaten it. In the present paper we try to apply behavioral science concepts and techniques to understanding problems of information security in organizations

Mitigation of Insider Attacks through Multi-Cloud

The malicious insider can be an employees, user and/or third party business partner. In cloud environment, clients may store sensitive data about their organization in cloud data centers. The cloud service provider should ensure integrity, security, access control and confidentiality about the stored data at cloud data centers. The malicious insiders can perform stealing on sensitive data at cloud storage and at organizations. Most of the organizations ignoring the insider attack because it is harder to detect and mitigate. This is a major emerging problem at the cloud data centers as well as in organizations. In this paper, we proposed a method that ensures security, integrity, access control and confidentiality on sensitive data of cloud clients by employing multi cloud service providers. The organization should encrypt the sensitive data with their security policy and procedures and store the encrypted data in trusted cloud. The keys which are used during encryption process are again encrypted and stored in another cloud area. So that organization contains only keys for keys of encrypted data. The Administrator of organization also does not know what data kept in cloud area and if he accesses the data, easily caught during the auditing. Hence, the only authorized used can access the data and use it and we can mitigate insider attacks by providing restricted privileges

A Study on IP Network Recovery through Routing Protocols

Internet has taken major role in our communication infrastructure. Such that requirement of internet availability and reliability has increasing accordingly. The major network failure reasons are failure of node and failure of link among the nodes. This can reduce the performance of major applications in an IP networks. The network recovery should be fast enough so that service interruption of link or node failure. The new path taken by the diverted traffic can be computed either at the time of failures or before failures. These mechanisms are known as Reactive and Proactive protocols respectively. In this paper, we surveyed reactive and proactive protocols mechanisms for IP network recovery

Structural and Electrochemical Characterization of Nanostructured Titanium Thin Films Prepared by DC Magnetron Sputtering with Supported Discharge

In this study, nanostructured titanium (Ti) thin films were prepared by direct current magnetron sputtering (diode mode) and supported discharge (triode mode) on a stainless steel substrate. The X-ray diffraction pattern shows a preferred orientation (002) plane and exhibits a hexagonal cubic structure for the film prepared at a lower working pressure (0.7 Pa). The electrical resistivity was found to be 15 mu ohm-cm. The scanning electron microscopy analysis indicates that the coatings in triode mode have agglomerates with larger grains compared to the DC magnetron sputtering diode mode. The surface topography was examined by atomic force microscopy. The electrochemical studies of the Ti thin films coated at a lower working pressure (0.7 Pa) provide evidence for better corrosion resistance

Influence of annealing on physical properties of evaporated SnS films

The effect of annealing on the composition, crystal structure, surface features and electro-optical properties of tin mono-sulfide (SnS) films, deposited by thermal evaporation at 300 °C, has been studied. Elemental analysis of the films shows sulfur deficiency, which increases at higher annealing temperatures (T<SUB>a</SUB>). The SnS structure in the as-deposited and annealed films remains orthorhombic. With an increase in T<SUB>a</SUB>, the grain size and the surface roughness are reduced. The electrical resistivity also decreases with increasing T<SUB>a</SUB>. The variation of activation energy and optical parameters with T<SUB>a</SUB> has been explained by taking into account the degree of preferred orientation of the grains. The films annealed at 100 °C show some unusual features compared to those annealed at other temperatures

The effect of substrate surface on the physical properties of SnS films

The effect of substrates on the physical properties of tin mono-sulphide (SnS) films has been studied. The SnS films were deposited using the resistive thermal evaporation method on CORNING 7059 glass, ITO-coated glass, Si wafer and Ag-coated glass substrates. The as-deposited films exhibited nearly stoichiometry between Sn and S elements with a Sn/S at.% ratio of ~1.05. Structural analysis of these films indicated that the films are crystallized in the form of an orthorhombic crystalline structure and showed (1 1 1) as a dominant peak, except for the films grown on Si substrates. Si/SnS films exhibited (0 4 0) as a dominant peak. The ITO/SnS films showed high values of rms roughness (~14.9 nm) and average grain size (~225 nm), along with a low electrical resistivity of 8.9 × 10-3 Ω cm as compared to SnS films grown on glass, Si and Ag substrates. The ITO/SnS films exhibit low resistivity, probably due to the large size of grains, and could be suitable for optoelectronic device applications

Microstructure dependent physical properties of evaporated tin sulfide films

In the field of photovoltaics, semiconductors of the III-V group such as GaAs and InP have been considered as the most efficient absorber materials due to their direct energy band gap and high mobility. In these compounds, arsenic and phosphorus are highly toxic and expensive. In this work we present systematic preparation of low cost SnS thin films and characterize these films to test their suitability for photovoltaic applications. We have observed that the films (with thickness ≅ 0.5 μ m) grown at the substrate temperature of 275°C exhibit a low resistive single SnS phase and have a direct optical band gap of 1.35 eV with an absorption coefficient of ~ 10<SUP>5</SUP> cm<SUP>-1</SUP>. SnS films could be alternative semiconductor materials as absorbers for the fabrication of photovoltaic devices