Cooperative Diversity in Secondary Systems: Efficient Relaying Protocol for Cognitive Radio

Wireless Personal Communications - This paper considers half-duplex cooperative spectrum sharing scheme where both primary and secondary systems mutually cooperate with each other to exploit...     

Electromechanical analytical model of shape memory alloy based tunable cantilevered piezoelectric energy harvester

International Journal of Mechanics and Materials in Design - The resonant frequency of electromechanical energy harvester should be tuned to ambient frequency so as to maximize the harvester power....     

Association Rule Mining Frequent-Pattern-Based Intrusion Detection in Network

In the network security system, intrusion detection plays a significant role. The network security system detects the malicious actions in the network and also conforms the availability, integrity and confidentiality of data information resources. Intrusion identification system can easily detect the false positive alerts. If large number of false positive alerts are created then it makes intrusion detection system as difficult to differentiate the false positive alerts from genuine attacks. Many research works have been done. The issues in the existing algorithms are more memory space and need more time to execute the transactions of records. This paper proposes a novel framework of network security Intrusion Detection System (IDS) using Modified Frequent Pattern (MFP-Tree) via K-means algorithm. The accuracy rate of Modified Frequent Pattern Tree (MFPT)-K means method in finding the various attacks are Normal 94.89%, for DoS based attack 98.34%, for User to Root (U2R) attacks got 96.73%, Remote to Local (R2L) got 95.89% and Probe attack got 92.67% and is optimal when it is compared with other existing algorithms of K-Means and APRIORI.     

Modeling basal ganglia for understanding Parkinsonian reaching movements

We present a computational model that highlights the role of basal ganglia (BG) in generating simple reaching movements. The model is cast within the reinforcement learning (RL) framework with correspondence between RL components and neuroanatomy as follows: dopamine signal of substantia nigra pars compacta as the temporal difference error, striatum as the substrate for the critic, and the motor cortex as the actor. A key feature of this neurobiological interpretation is our hypothesis that the indirect pathway is the explorer. Chaotic activity, originating from the indirect pathway part of the model, drives the wandering, exploratory movements of the arm. Thus, the direct pathway subserves exploitation, while the indirect pathway subserves exploration. The motor cortex becomes more and more independent of the corrective influence of BG as training progresses. Reaching trajectories show diminishing variability with training. Reaching movements associated with Parkinson's disease (PD) are simulated by reducing dopamine and degrading the complexity of indirect pathway dynamics by switching it from chaotic to periodic behavior. Under the simulated PD conditions, the arm exhibits PD motor symptoms like tremor, bradykinesia and undershooting. The model echoes the notion that PD is a dynamical disease.     

A review of channel estimation and security techniques for CRNS

Cognitive Radio Network (CRN) is an intelligent wireless communication system that adapts itself to variations in the incoming radio frequency stimuli by modifying the operating parameters. Using the spectrum sensing techniques, the idle channels are detected, and allocated to the Secondary Users (SUs). The existing cooperative spectrum sensing techniques such as centralized sensing technique, Distributed sensing technique, and External sensing technique exploit efficient prediction models for allocating the frequency spectrum to SUs. For an optimal assignment of the channel using channel parameters, the channel estimation techniques such as pilot-assisted channel estimation, blind and semi blind estimation technique, and decision directed channel estimation technique are analyzed. The flexible nature of the CRN introduces various security attacks such as Primary User Emulation Attack, Objective Function Attack, Jamming Attack, Spectrum Sensing Data Falsification (SSDF), Control Channel Saturation DoS Attack (CCSD), Selfish Channel Negotiation (SCN), Sinkhole Attacks, HELLO Flood Attacks and Lion Attack. From the surveyed results, it is observed that the existing spectrum sensing, and prediction-based techniques consume more energy, and minimal data transmission rate for detecting the idle channel. Further, the end-to-end delay, energy consumption, end-to-end delay, and bandwidth are not minimized by the existing techniques.     

Synthesis and characterization studies of ZnSe quantum dots

ZnSe QDs have been synthesized by wet chemical, template free process by zinc acetate and elemental selenium powder in presence of ethylene glycol, hydrazine hydrate and a defined amount of water at 90 °C. The product was in strong quantum confinement regime, having yield as high as 50 %. The transmission electron microscopy image indicated that the particles were well dispersed and spherical in shape. The X-ray diffraction analysis showed that the ZnSe nanoparticles were of the Cubic structure, with average particle diameter of about 3.50 nm. The FTIR characteristic indicates that the N₂H₄ molecule has intercalated into the complex and formed a molecular precursor.     

Effect of SiC on Mechanical and Microstructural Characteristics of Al Based Functionally Graded Material

Silicon - In this study, an attempt was made to enhance the mechanical and microstructural properties of aluminium (Al) based FGM with the influence of silicon carbide (SiC) elements. The five...     

Radioactive contamination measurements of the primary sodium pipes in FBTR by gamma spectrometry

Gamma spectrometric measurements were carried out in the primary sodium pipes of FBTR, twice during shut down state of the reactor with sodium circulating at 180 °C and once after draining the primary sodium from pipes. However, the first two measurements were mainly the feasibility studies of undertaking gamma spectrometric measurements inside the primary sodium cells and to establish a reference on the build up of radiation field in the cells due to the deposition of radionuclides on the walls of the primary sodium pipelines. For estimating the specific activity of radionuclides in the circulating sodium as well as deposited ones on the interiors of pipes, calibration curves were generated by simulating the geometry conditions. Third spectral measurement was performed after 651 EFPD of reactor operation under two scenarios, sodium circulating at 180 °C and sodium drained out from the primary sodium pipes. The radionuclides observed before draining of sodium are ⁵⁴Mn, ⁵⁸Co and ⁶⁰Co due to corrosion products and ²⁰³Hg, ²²Na and ²⁴Na due to activation products of coolant and the soluble impurities in it. Trace quantities of ⁶⁵Zn, ⁵⁹Fe and ¹²⁴Sb were also seen. Once the primary sodium is drained from the pipelines, the major radionuclides deposited inside the walls of the pipelines and their specific activities are, ⁵⁴Mn (17,700 kBq/m²), ²²Na, ⁶⁰Co and ⁵⁸Co (∼350 kBq/m² each) and ⁶⁵Zn (250 kBq/m²). These results indicate that the handling of components for maintenance work inside the cells housing primary sodium pipes, if warranted, is not much of a radiological concern.