Size optimization of a PV/wind hybrid energy conversion system with battery storage using response surface methodology

This paper aims to show the use of the response surface methodology (RSM) in size optimization of an autonomous PV/wind integrated hybrid energy system with battery storage. RSM is a collection of statistical and mathematical methods which relies on optimization of response surface with design parameters. In this study, the response surface, output performance measure, is the hybrid system cost, and the design parameters are the PV size, wind turbine rotor swept area and the battery capacity. The case study is realized in ARENA 10.0, a commercial simulation software, for satisfaction of electricity consumption of the global system for mobile communications (GSM) base station at Izmir Institute of Technology Campus Area, Urla, Turkey. As a result, the optimum PV area, wind turbine rotor swept area, and battery capacity are obtained to be 3.95 m², 29.4 m², 31.92 kWh, respectively. These results led to $37,033.9 hybrid energy system cost, including auxiliary energy cost. The optimum result obtained by RSM is confirmed using loss of load probability (LLP) and autonomy analysis.     

Contrast enhancement by modified octagon histogram equalization

Histogram equalization is the common method used for contrast enhancement. The mean brightness of the image is adjusted to middle of the permitted range and hence is not suitable for consumer electronics products. A novel contrast enhancement method using modified octagon histogram equalization is developed to overcome the drawback of conventional technique for gray scale images. The proposed algorithm is applied for boat image, microstructure of steel and human head. The contrast enhanced out of the images mentioned is obtained, and the efficiency of the algorithm is evaluated. Simulation results shows that the proposed method can enhance the different types of images effectively. Besides, the proposed contrast enhancement method using modified octagon histogram equalization has comparable performance with black and white stretching and adaptive histogram equalization.     

Fully differential operational amplifiers with accurate outputbalancing

Design considerations are presented for attaining accurate output balancing in fully differential operational amplifiers over the useful operating frequency of the differential signals. Such output balancing is obtained by merging the common-mode feedback and the differential gain paths as close to the front end of the amplifier as possible, ensuring maximum sharing of circuit components. Two circuit designs implemented in a 5-V, 1.75-μm process are presented, one based on a two-stage topology and one based on a folded cascode topology. Experimental results for both designs are given     

A submicrometer NMOS multiplexer-demultiplexer chip set for 622.08-Mb/s SONET applications

The development of a low-power 12-channel multiplexer-demultiplexer pair that is clocked at the standard synchronous optical network (SONET) rate of 622.08 MHz is discussed. Each device has been integrated in silicon using a 0.75- mu m NMOS VLSI technology that provides high fabrication yield at relatively low cost. Highlighted are the analog interface circuits of the two chips. These include a phase splitter and amplifier for the maser clock input, a precision 50- Omega output driver for high-speed synchronous-transport-signal-12 (STS-12) data, as well as input amplifier and an output stage for low-speed differential STS-1 data.<>     

Theophylline‐loaded pectin‐based hydrogels. I. Effect of medium pH and preparation conditions on drug release profile

In this study, a series of theophylline‐loaded calcium pectin gel films were prepared in three different Ca⁺² concentrations with three different methods for wound dressing applications. Drug release performance of the films were investigated in four different medium pH in order to mimic wound healing pH conditions. Hydrogel films were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy and atomic force microscopy. Their absorbency (fluid handling), swelling behavior, dehydration rate, dispersion characteristic, dressing pH determination, water vapor permeability, oxygen permeability, surface contact angle, flexibility, Shore A hardness, mean mass per unit area and thickness were determined. The effect of the hydrogels on wound healing was evaluated with an in vitro wound healing assay. After evaluating all data, we suggested that the hydrogel film prepared with swelling method using 7% or 10% crosslinker and dried at 26 °C is more suitable for controlled drug release process. We showed that between pH 3.25 and 7.12 the form of the hydrogel did not change, and drug release was continuous. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46731.     

Tri-level scrambling and enhanced diffusion for DICOM image cipher- DNA and chaotic fused approach

Tele-health and e-healthcare are some of the innovative e-commerce appliances that can eliminate the barrier between time and distance among health care centres and patients. The proposed work approaches the obstacle to secure digital medical image data in a public cloud. The most crucial part of e-healthcare and telemedicine industries is cyber-attacks. To thwart cyber-attacks, it is necessary to protect the medical images and transmit them securely. In this paper, a novel way of scrambling and Deoxyribonucleic Acid (DNA) sequence operations is performed to encrypt the digital medical images. A chaotic tri-level scrambling is carried out by a two dimensional Tinkerbell map. Experimental outcomes and security analyses such as statistical, differential, keyspace, encryption quality, along with chosen-plaintext attack analysis have been perpetrated to determine the feasibility and potency of the proposed Digital Imaging and Communications in Medicine (DICOM) image encryption method. The algorithm attains average entropy of 7.99 and near-zero correlation with NPCR and UACI of 99.6 and 33.4, respectively. Further, the efficiency of the algorithm is compared with the state of the literature encryption techniques.

     

Feature selection using swarm-based relative reduct technique for fetal heart rate

Fetal heart rate helps in diagnosing the well-being and also the distress of fetal. Cardiotocograph (CTG) monitors the fetal heart activity to estimate the fetal tachogram based on the evaluation of ultrasound pulses reflected from the fetal heart. It consists in a simultaneous recording and analysis of fetal heart rate signal, uterine contraction activity and fetal movements. Generally CTG comprises more number of features. Feature selection also called as attribute selection is a process of selecting a subset of highly relevant features which is responsible for future analysis. In general, medical datasets require more number of features to predict an activity. This paper aims at identifying the relevant and ignores the redundant features, consequently reducing the number of features to assess the fetal heart rate. The features are selected by using unsupervised particle swarm optimization (PSO)-based relative reduct (US-PSO-RR) and compared with unsupervised relative reduct and principal component analysis. The proposed method is then tested by applying various classification algorithms such as single decision tree, multilayer perceptron neural network, probabilistic neural network and random forest for maximum number of classes and clustering accuracies like root mean square error, mean absolute error, Davies–Bouldin index and Xie–Beni index for minimum number of classes. Empirical results show that the US-PSO-RR feature selection technique outperforms the existing methods by producing sensitivity of 72.72 %, specificity of 97.66 %, F-measure of 74.19 % which is remarkable, and clustering results demonstrate error rate produced by US-PSO-RR is less as well.     

Optical Brain Imaging to Enhance UAV Operator Training, Evaluation, and Interface Development

As the use of unmanned aerial vehicles expands to near earth applications and force multiplying scenarios, current methods of operating UAVs and evaluating pilot performance need to expand as well. Many human factors studies on UAV operations rely on self reporting surveys to assess the situational awareness and cognitive workload of an operator during a particular task, which can make objective evaluations difficult. Functional Near-Infrared Spectroscopy (fNIR) is an emerging optical brain imaging technology that monitors brain activity in response to sensory, motor, or cognitive activation. fNIR systems developed during the last decade allow for a rapid, non-invasive method of measuring the brain activity of a subject while conducting tasks in realistic environments. This paper investigates deployment of fNIR for monitoring UAV operator’s cognitive workload and situational awareness during simulated missions. The experimental setup and procedures are presented with some early results supporting the use of fNIR for enhancing UAV operator training, evaluation and interface development.     

Effect of novel (Gd,Cu) substitution on the electrical properties and magnetoelectric coupling of bismuth ferrite ceramics

The influence of Gd dopant and (Gd, Cu) dopants on the ferroelectric, dielectric and magnetoelectric properties of single phase BiFeO₃ (BFO) were investigated. Nanoparticles of undoped BiFeO₃, Bi_0.95Gd_0.05FeO₃ and Bi_1?xGd_xFe_0.98Cu_0.02O₃ (x?=?1, 2, 3, 4 and 5%) were prepared by sol–gel method. X-ray diffraction reveals that all the samples crystallize in rhombohedral phase. The simultaneous Gd and Cu doping at BFO lattice has significantly enhanced the ferroelectric properties of BFO compared to that of BFO. Substitution of Gd alone at the Bi site, gave rise to attractively enhanced remnant polarization. Though the (Gd, Cu) doped BFO samples exhibit relatively less enhancement, their values of remnant polarization are appreciable. Doping of (Gd, Cu) in the BFO lattice leads to an appreciable dielectric properties. An effective magnetoelectric coupling has been recorded for doped BFO when compared to BFO.