Robust Aggregation Mechanism in WSN for Mitigating Attacks

Wireless Sensor Network (WSN) is a collection of sensor nodes connected to base station which is characterized by many to one communication. Many sensor nodes will send data to base station making it many to on communication. The sensor nodes can act as sender and receiver of data as the data is sent to base station through intermediary nodes. The nodes are resource constrained as they are deployed in hostile environment or environment where resources are limited. The nodes are expected to participate in sensing or surveillance. WSNs are widely used in civilian and military applications for sending data and surveillance. As WSN is becoming increasingly popular, security needs to be provided in the network as the nodes are vulnerable to various attacks. Since the nodes are energy constrained, it is very useful to use some aggregation technique in order to reduce communication overhead and also energy consumption. Recently Roy et al. focused on aggregation in WSN for filtering out the impact of attackers on the network. Their focus was to use aggregation in WSN in order to reduce communication overhead and reduce the impact of attacks on WSN. In this paper we implement a variant of protocol that takes care of secure communications over WSN besides reducing energy consumption and mitigating attack impact. The simulation results are encouraging DOI: 10.17762/ijritcc2321-8169.15065

Group Based Secure Sharing of Cloud Data with Provable Data Freshness

With cloud computing technology it is realized that data can be outsource and such data can also be shared among users of cloud. However, the data outsourced to cloud might be subjected to integrity problems due to the problems in the underlying hardware or software errors. Human errors also may contribute to the integrity problems. Many techniques came into existence in order to ensure data integrity. Most of the techniques have some sort of auditing. Public auditing schemes meant for data integrity of shared data might disclose confidential information. To overcome this problem, recently, Wang et al. proposed a novel approach that supports public auditing and also do not disclose confidential information. They exploited ring signatures that are used to compute verification metadata on the fly in order to audit the correctness of shared data. The public verifiers do not know the identity of the signer. It does mean that the verifier can verify data without knowing the identity of the signer. However, this scheme does not consider the freshness of data which is very important in cloud services. Obtaining latest copy of data is very important to avoid stale data access in cloud. Towards this end, in this paper, we proposed an algorithm for ensuring freshness of the data while retrieving the outsourced data in multi-user environment. Our empirical results revealed that the proposed algorithm is efficient. DOI: 10.17762/ijritcc2321-8169.15065

A Framework for Protecting Cloud Users from Third Party Auditors

Cloud computing has merged to be a now computing paradigm that lets public to access shared pool of resources without capital investment. The users of cloud need to access resources through Internet in pay per use fashion. Thus there is increased use of storage services of cloud in the real world. This service is known as Infrastructure as a Service (IaaS). However, there are security concerns as this service runs in entrusted environment. To ensure data integrity many public verification or auditing schemes came into existence. Nevertheless, there is a concern when the so called Third Party Auditor (TPA) has malicious intentions. In such cases, protection is required against malicious TPAs. Towards this end, recently, Huang et al. proposed a scheme in which users can directly check the integrity of stored data using a feedback based audit scheme. TPA takes process proof from cloud server and gives feedback to cloud user. The feedback is unforgivable and the TPA cannot make any malicious attacks. Based on this scheme, in this paper, we implemented a prototype application that demonstrates the proof of concept. The empirical results are encouraging. DOI: 10.17762/ijritcc2321-8169.15065

Investigation of the obscure spin state of Ti-doped CdSe

Using computational and experimental techniques, we examine the nature of the 2+ oxidation of Ti-doped CdSe. Through stoichiometry and confirmed through magnetization measurements, the weakly-doped material of Cd1-xTixSe (x = 0.0043) shows the presence of a robust spin-1 magnetic state of Ti, which is indicative of a 2+ oxidation state. Given the obscure nature of the Ti2+ state, we investigate the electronic and magnetic states using density functional theory. Using a generalized gradient approximation with an onsite potential, we determine the electronic structure, magnetic moment density, and optical properties for a supercell of CdSe with an ultra-low concentration of Ti. We find that, in order to reproduce the magnetic moment of spin-1, an onsite potential of 4-6 eV must be in included in the calculation. Furthermore, the electronic structure and density of states shows the presence of a Ti-d impurity band above the Fermi level and a weakly metallic state for a U = 0 eV. However, the evolution of the electronic properties as a function of the Hubbard U shows that the Ti-d drop below the Fermi around 4 eV with the onset of a semiconducting state. The impurity then mixes with the lower valence bands and produces the 2+ state for the Ti atom

Exchange in silicon-based quantum computer architecture

The silicon-based quantum computer proposal has been one of the intensely pursued ideas during the past three years. Here we calculate the donor electron exchange in silicon and germanium, and demonstrate an atomic-scale challenge for quantum computing in Si (and Ge), as the six (four) conduction band minima in Si (Ge) lead to inter-valley electronic interferences, generating strong oscillations in the exchange splitting of two-donor two-electron states. Donor positioning with atomic scale precision within the unit cell thus becomes a decisive factor in determining the strength of the exchange coupling--a fundamental ingredient for two-qubit operations in a silicon-based quantum computer.Comment: 5 pages, 2 figure

Understanding the spin-glass state through the magnetic properties of Mn-doped ZnTe

Magnetic measurements on the spin-glass behavior in the bulk II-VI diluted magnetic semiconductor (DMS) ZnMnTe were made on two crystals of concentrations x = 0.43 and 0.55 taken from the same boule. Magnetization and density functional theory studies have shown paramagnetic behavior in both samples between 30 and 400 K. Below 30 K, there is a prominent peak at Tc = 15 and 23.6 K for concentrations x = 0.43 and 0.55, respectively. The splitting of the field cooled (FC) and zero field cooled (ZFC) data below this peak is indicative of a transition to a spin-glass state at low temperature for semiconductors. Therefore, through the p− and d− orbits hybridization a magnetic exchange produces the spin-glass behavior seen in the DMS ZnMnTe

FORMULATION AND EVALUATION OF GASTRORETENTIVE FLOATING TABLETS OF LAFUTIDINE

The purpose of this research was to develop a novel gastroretentive drug delivery system based on wet granulation technique for sustained delivery of active agent. Quick GI transit could result in incomplete drug release from the drug delivery system above the absorption zone leading to decreased efficacy of the administered dose and thus less patient compliance. Gastroretentive floating tablets, which was designed to provide the desired sustained and complete release of drug for prolonged period of time. Gastroretentive floating tablets of lafutidine were prepared by wet granulation technique using different concentrations of Gum Kondagagu, Gum olibanum and Locust bean Gum. The optimized formulation (LF14) exhibited 99.54% drug release in 12 hrs, while the buoyancy lag time was 33 sec. In-vitro drug release kinetics was found to follow both the Zero order and the possible mechanism of lafutidine release from the optimized formulation might be attributed to super case II transport mechanism. The Optimized formulation (LF14) showed no significant change in physical appearance, drug content, floating lag time, in vitro dissolution studies after 75%±5% RH at 40±20C relative humidity for 6 months. Keyword: Wet granulation, Floating lag Time, Gastroretentive, Lafutidin

Direct observation by resonant tunneling of the B^+ level in a delta-doped silicon barrier

We observe a resonance in the conductance of silicon tunneling devices with a delta-doped barrier. The position of the resonance indicates that it arises from tunneling through the B^+ state of the boron atoms of the delta-layer. Since the emitter Fermi level in our devices is a field-independent reference energy, we are able to directly observe the diamagnetic shift of the B^+ level. This is contrary to the situation in magneto-optical spectroscopy, where the shift is absorbed in the measured ionization energy.Comment: submitted to PR

Evolution of magnetic polarons and spin-carrier interactions through the metal-insulator transition in Eu1−x_{1-x}Gdx_{x}O

Raman scattering studies as functions of temperature, magnetic field, and Gd-substitution are used to investigate the evolution of magnetic polarons and spin-carrier interactions through the metal-insulator transition in Eu$_{1-x}$Gd$_{x}$O. These studies reveal a greater richness of phase behavior than have been previously observed using transport measurements: a spin-fluctuation-dominated paramagnetic (PM) phase regime for T $>$ T$^{*}$ $>$ T$_{C}$, a two-phase regime for T $<$ T$^{*}$ in which magnetic polarons develop and coexist with a remnant of the PM phase, and an inhomogeneous ferromagnetic phase regime for T $<$ T$_{C}$