Investigation of Magnetocaloric Behavior of Nanocrystalline Nd0.67A0.33MnO3, (A = Ca,Sr, Ba and Pb)

Colossal magnetoresistive (CMR) materials with the compositional formula, Nd_0.67A_0.33MnO₃ (where A = Ca, Sr, Ba, and Pb) in the nanocrystalline form were prepared by the PVA gel technique. After characterizing the samples structurally, a systematic investigation of magnetization has been undertaken, over a temperature range 10–300 K at 0.05 T magnetic field. An effort has been made to calculate the magnetocaloric behavior of all the samples theoretically using the experimental magnetization data. Other important parameters such as maximum entropy change, full width at half-maximum, relative cooling power, and maximum adiabatic temperature change under 0.05 T were also computed. The observed behavior has been explained qualitatively.     

A hybrid clustering procedure for concentric and chain-like clusters

K-means algorithm is a well known nonhierarchical method for clustering data. The most important limitations of this algorithm are that: (1) it gives final clusters on the basis of the cluster centroids or the seed points chosen initially, and (2) it is appropriate for data sets having fairly isotropic clusters. But this algorithm has the advantage of low computation and storage requirements. On the other hand, hierarchical agglomerative clustering algorithm, which can cluster nonisotropic (chain-like and concentric) clusters, requires high storage and computation requirements. This paper suggests a new method for selecting the initial seed points, so that theK-means algorithm gives the same results for any input data order. This paper also describes a hybrid clustering algorithm, based on the concepts of multilevel theory, which is nonhierarchical at the first level and hierarchical from second level onwards, to cluster data sets having (i) chain-like clusters and (ii) concentric clusters. It is observed that this hybrid clustering algorithm gives the same results as the hierarchical clustering algorithm, with less computation and storage requirements.     

Spatial–spectral ant colony optimization for hyperspectral image classification

Hyperspectral satellite images contain a lot of information in terms of spectral behaviour of objects and this information can be extracted by several mechanisms including image classification. Traditional spectral information-based methods of hyperspectral image classification are generally followed by spatial information-driven post-processing techniques such as relaxation labelling and Markov Random Field. Spectral or spatial information alone may lead to different results depending upon scene captured. An algorithm which can incorporate influence of both spectral and spatial features is needed to address this problem. In this article, an ant colony optimisation-based hyperspectral image classification technique is proposed. This method exploits both spatial and spectral features. Five standard hyperspectral data sets have been used to validate the proposed method and comparisons with other approaches have been carried out. It was observed that the proposed method yielded a significant improvement in classification accuracy. For the instance, nearly 10% increase in accuracy was observed when compared to Support Vector Machine for Indian pines, Botswana, and Salinas images.     

Application-Level Fault Tolerance as a Complement to System-Level Fault Tolerance

As multiprocessor systems become more complex, their reliability will need to increase as well. In this paper we propose a novel technique which is applicable to a wide variety of distributed real-time systems, especially those exhibiting data parallelism. System-level fault tolerance involves reliability techniques incorporated within the system hardware and software whereas application-level fault tolerance involves reliability techniques incorporated within the application software. We assert that, for high reliability, a combination of system-level fault tolerance and application-level fault tolerance works best. In many systems, application-level fault tolerance can be used to bridge the gap when system-level fault tolerance alone does not provide the required reliability. We exemplify this with the RTHT target tracking benchmark and the ABF beamforming benchmark.     

A novel DNA-inspired encryption strategy for concealing cloud storage

Over the last few years, the need of a cloud environment with the ability to detect illegal behaviours along with a secured data storage capability has increased largely. This study presents such a secured cloud storage framework comprising of a deoxyribonucleic acid (DNA) based encryption key which has been generated to make the framework unbreakable, thus ensuring a better and secured distributed cloud storage environment. Furthermore, this work proposes a novel DNAbased encryption technique inspired by the biological characteristics of DNA and the protein synthesis mechanism. The introduced DNA based model also has an additional advantage of being able to decide on selecting suitable storage servers from an existing pool of storage servers on which the data must be stored. A fuzzy-based technique for order of preference by similarity to ideal solution (TOPSIS) multi-criteria decisionmaking (MCDM) model has been employed to achieve the above-mentioned goal. This can decide the set of suitable storage servers and also results in a reduction in execution time by keeping up the level of security to an improved grade. This study also investigates and analyzes the strength of the proposed S-Box and encryption technique against some standard criteria and benchmarks, such as avalanche effect, correlation coefficient, information entropy, linear probability, and differential probability etc. After the avalanche effect analysis, the average change in cipher-text has been found to be 51.85%. Moreover, thorough security, sensitivity and functionality analysis show that the proposed scheme guarantees high security with robustness.     

Effects of cobalt (III) complexes of schiff bases on root tip mitosis

Cytological effects of two newly synthesized Cobalt (III) complexes, namely, [Co(BSOP)(NH₃)₂] [NO₃], (1) and [Co(BSOP)(PY)₂] [NO₃], (2) (where, BSOP = dianion of N, N‐orthophenylenebis (salicylal‐dimine), Py = pyridine) were studied on Allium Cepa root tip cells. Many interesting abnormalities, including diplochromatic structure, grouping, stickiness, beadedness, erosion, fragmentation and bridge formation of chromosomes and granulation of the interphase nucleus were observed under the influence of these cobalt (III) complexes. The mitotic index had been simulated at threshold concentrations, but affected at higher concentrations and prolonged treatment. The inhibitory action in prolonged treatment may be due to an accumulation effect. Mechanisms of such effects have been discussed qualitatively and are described as a non‐delayed type.