IEVCA: An efficient image encryption technique for IoT applications using 2-D Von-Neumann cellular automata

Multimedia Tools and Applications - Present era is marked by exponential growth in transfer of multimedia data through internet. Most of the Internet-of-Things(IoT) applications send images to...     

An improved transport layer protocol for wireless sensor networks

Wireless sensor networks (WSNs) are a kind of communication networks having independent sensor nodes that form multi-hop ad hoc network to transfer data. In the past few years, various transport control protocols in wireless sensor networks (WSNs) have been developed and proposed in the literature. In this paper, we have analyzed pump slowly, fetch quickly (PSFQ) protocol and presented an improved transport layer protocol for wireless sensor networks. The improved protocol has been analyzed based on various factors such as average latency and average error tolerance and it is found that the proposed protocol is better than PSFQ in terms of these factors.     

Renewable hydrogen generation by steam reforming of glycerol over zirconia promoted ceria supported catalyst

The study focuses on hydrogen production from steam reforming of glycerol over nickel based catalyst promoted by zirconia and supported over ceria. Catalyst was prepared by the wet-impregnation method and characterized by BET surface area analysis, X-ray diffraction technique and scanning electron microscopy (SEM) analysis. The performance of the catalyst was evaluated in terms of hydrogen yield, selectivity and glycerol conversion at 700 °C in a tubular fixed bed reactor. The effect of glycerol concentration in feed, space time (W/F_AO), temperature and time on stream (TOS) was analyzed for the catalyst Ni–ZrO₂/CeO₂ which showed the complete conversion of glycerol and high H₂ yield that corresponds to 3.95 mol of H₂ out of 7 mol. Thermodynamic analysis was also carried out using Aspen HYSYS for system having glycerol concentration 10 wt% and 20 wt% and experimental results were compared with thermodynamics. Kinetic study was carried out for the steam reforming of glycerol over Ni–ZrO₂/CeO₂ catalyst using the power law model. The values of activation energy and order of reaction were found to be 43.4 kJ/mol and 0.3 respectively.     

Development and evaluation of orally disintegrating tablets of cilostazol-β-cyclodextrin inclusion complexes

Context: The clinical applications of cilostazol (CLZ) are limited by its low aqueous solubility (<5?µg/ml) and high biovariability.

Objective: The aim of this study was to enhance the solubility of CLZ by forming inclusion complexes (ICs) with beta cyclodextrin (β-CD) and formulating them into oral disintegrating tablets.

Methods: Phase solubility study of CLZ with β-CD was performed in water. Job’s plot was constructed to determine the stoichiometry of ICs. ICs, prepared by spray-drying technique, were characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, hot stage microscopy, powder X-ray diffraction and nuclear magnetic resonance. Molecular modeling studies were performed to understand the mode of interaction of CLZ with β-CD. The formulation process was undertaken using a reproducible design of experiment generated model, attained by variation of diluents and disintegrants at three levels. Tablets were evaluated for drug content, hardness, friability, disintegration time (DT), wetting time (WT) and dissolution profiles.

Results and discussion: Phase solubility studies suggested an A_L type curve with stability constant (K_s) of 922.52?M^?1. Job’s plot revealed 1:2 stoichiometry. All analytical techniques confirmed inclusion complexation. Molecular modeling revealed dispersive van der Waals interaction energy as a major contributor for stabilization of complex. The spray-dried complexes showed higher solubility and faster dissolution compared to plain CLZ. The optimized formulation showed DT of 11.1?±?0.8?s, WT of 8.7?±?0.9?s and almost complete dissolution of CLZ in 15?min.

Conclusion: The prepared tablets with low DT and fast dissolution will prove to be a promising drug delivery system with improved bioavailability and better patient compliance.     

Silver nanoparticle anchored with novel crosslinked beaded polystyrene/polyamidoxime sequential interpenetrating polymer networks (IPNs) and its antibacterial activity

The present article describes the synthesis of silver nanoparticles (SNPs) impregnatated crosslinked beaded polystyrene/polyamidoxime (PSD/PAMD) interpenetrating polymer networks (IPNs). The developed SNPs‐IPNs were tested for the antibacterial activity for water purification. Intially, the crosslinked beaded polystyrene/polyacrylonitrile (PSD/PAN) polymer was synthesized by radical sequential suspension polymerization method therafter, it has been converted into PSD/PAMD‐IPN comprising amidoxime group, which acts as capping agent to anchor the silver ions. The silver ions impregnated with PSD/PAMD‐IPN were converted into SNPs by chemical reduction methodology followed by stabilization without any deterioration or loss in polymer. IR and solid‐state ¹³C NMR spectra were use for the structural characterization of developed SNPs‐IPN, while morphological characterization was examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD). The size of the SNPs formed with the networks were found less than 5 nm. The disinfection potential of SNPs‐IPN was evaluated by different antibacterial test. The bactericidal test of SNPs‐IPN revealed the promissing antibacterial efficieny with complete microbial inhibition within 4–6 h. The reusability of the SNPs‐IPN beads was also tested for its repeated use for industrial application. POLYM. COMPOS., 70–80, 2016. © 2014 Society of Plastics Engineers     

《通过对改造前后建筑物数据进行聚类分析确定影响办公建筑能源消耗的关键变量》

本研究旨在确定影响空调办公建筑能耗的关键建筑设计变量。本研究基于热带气候条件下的新加坡进行。结合56个办公楼改造前后能源审计报告数据进行评估分析。从这些报告中提取的14个建筑变量的列表构成了超集。对这些数据进行系统分析,得出影响能耗和改造决策的关键变量。为此,利用k均值聚类确定了一个稳健的迭代过程。该过程对14个变量的所有组合进行了测试,以应对改造前后条件下的能源使用强度(EUI,kW·h/m~2·a)的变化。结果表明,最佳变量包括:1)总建筑面积(GFA);2)非空调能耗;3)冷却装置的平均效率;4)冷却装置的装机容量。这些信息可以用来探索需要改造的办公楼的节能潜力。由此产生的集群还可以用来根据改造前的条件和节能潜力来对建筑物进行基准测试。     

An improved multimodal medical image fusion scheme based on hybrid combination of nonsubsampled contourlet transform and stationary wavelet transform

This research proposes an improved hybrid fusion scheme for non-subsampled contourlet transform (NSCT) and stationary wavelet transform (SWT). Initially, the source images are decomposed into different sub-bands using NSCT. The locally weighted sum of square of the coefficients based fusion rule with consistency verification is used to fuse the detailed coefficients of NSCT. The SWT is employed to decompose approximation coefficients of NSCT into different sub-bands. The entropy of square of the coefficients and weighted sum-modified Laplacian is employed as the fusion rules with SWT. The final output is obtained using inverse NSCT. The proposed research is compared with existing fusion schemes visually and quantitatively. From the visual analysis, it is observed that the proposed scheme retained important complementary information of source images in a better way. From the quantitative comparison, it is seen that this scheme gave improved edge information, clarity, contrast, texture, and brightness in the fused image.     

HEART: Unrelated parallel machines problem with precedence constraints for task scheduling in cloud computing using heuristic and meta-heuristic algorithms

Cloud computing is becoming a profitable technology because of it offers cost-effective IT solutions globally. A well-designed task scheduling algorithm ensures the optimal utilization of clouds resources and reducing execution time dynamically. This research article deals with the task scheduling of inter-dependent subtasks on unrelated parallel computing machines in a cloud computing environment. This article considers two variants of the problem-based on two different objective function values. The first variant considers the minimization of the total completion time objective function while the second variant considers the minimization of the makespan objective function. Heuristic and meta-heuristic (HEART) based algorithms are proposed to solve the task scheduling problems. These algorithms utilize the property of list scheduling algorithm of unrelated parallel machine scheduling problem. A mixed integer linear programming (MILP) formulation has been provided for the two variants of the problem. The optimal solution is obtained by solving MILP formulation using A Mathematical Programming Language (AMPL) software. Extensive numerical experiments have been performed to evaluate the performance of proposed algorithms. The solutions obtained by the proposed algorithms are found to out-perform the existing algorithms. The proposed algorithms can be used by cloud computing service providers (CCSPs) for enhancing their resources utilization to reduce their operating cost.     

Virtualization layer security challenges and intrusion detection/prevention systems in cloud computing: a comprehensive review

Virtualization plays a vital role in the construction of cloud computing. However, various vulnerabilities are existing in current virtualization implementations, and thus there are various security challenges at virtualization layer. In this paper, we investigate different vulnerabilities and attacks at virtualization layer of cloud computing. We examine the proposals of cloud intrusion detection system (IDS) and intrusion detection and prevention system frameworks. We recommend the cloud IDS requirements and research scope to achieve desired level of security at virtualization layer of cloud computing.     

Preparation and characterization of spray-dried mucoadhesive microspheres of aceclofenac

Objective: Microencapsulation of the anti-inflammatory drug aceclofenac (ACE) was investigated as a means of controlling drug release and minimizing or eliminating local side effects. Method: Microspheres were prepared by a spray-drying technique using solutions of ACE and three polymers, namely, carbopol, chitosan, and polycarbophil, in different weight ratios. Results: The spray-dried mucoadhesive microspheres were characterized in terms of shape (scanning electron microscope), size (6.60–8.40 μm), production yield (34.10–55.62%), and encapsulation efficiency (58.14–90.57%). In vitro release studies were performed in phosphate buffer (pH 6.8) up to 10 hours. The spray-drying process of solutions of ACE with polymeric blends can give prolonged drug release. The in vitro release data were well fit into Higuchi and Korsmeyer–Peppas model and followed Fickian diffusion mechanism. In vivo data showed that the administration of ACE in polymeric microspheres prevented the gastric side effects. Conclusion: The formulations here described can be proposed for the oral administration of nonsteroidal anti-inflammatory drugs with minimal side effects on gastric mucosa.