No-chatter model-free sliding mode control for synchronization of chaotic fractional-order systems with application in image encryption

Multimedia Tools and Applications - Synchronization of different Chaotic dynamical systems is one of the main issues in engineering which has a lot of applications in applied sciences like secure...     

Predicting roadheader performance by using artificial neural network

With growing use of roadheaders in the world and its significant role in the successful accomplishment of a tunneling project, it is a necessity to accurately predict performance of this machine in different ground conditions. On the other hand, the existence of some shortcomings in the prediction models has made it necessary to perform more research on the development of the new models. This paper makes an attempt to model the rate of roadheader performance based on the geotechnical and geological site conditions. For achieving the aim, an artificial neural network (ANN), a powerful tool for modeling and recognizing the sophisticated structures involved in data, is employed to model the relationship between the roadheader performance and the parameters influencing the tunneling operations with a high correlation. The database used in modeling is compiled from laboratory studies conducted at Azad University at Science and Research Branch, Tehran, Iran. A model with architecture 4-10-1 trained by back-propagation algorithm is found to be optimum. A multiple variable regression (MVR) analysis is also applied to compare performance of the neural network. The results demonstrate that predictive capability of the ANN model is better than that of the MVR model. It is concluded that roadheader performance could be accurately predicted as a function of unconfined compressive strength, Brazilian tensile strength, rock quality designation, and alpha angle R ² = 0.987. Sensitivity analysis reveals that the most effective parameter on roadheader performance is the unconfined compressive strength.     

Landsat ETM+ imaging for mineral potential mapping: application to Avaj area,Qazvin, Iran

The Avaj area is located in the northwestern part of Iran, on the boundary between the Orumieh-Dokhtar and Sanandaj-Sirjan geological zones. It corresponds to two different geological sub-zones:Abe-Garm, to the north, which is related to the volcanic belt of Orumieh-Dokhtar; and the Razan sub-zone, to the south, which is related to the Sanandaj-Sirjan zone. Lithological aspects of different rock units indicate the presence of four distinct volcanic groups of andesite, basalt, tuff, and dacite. The present research utilizes various Landsat Enhanced Thematic Mapper Plus (ETM+) image-processing techniques, including false colour composite images, colour composite ratio images, and standard principal component (PC) image analysis on six bands and colour composite selective PC images, filtering and supervised classification. Nonetheless, colour composite selective images may be the most reliable method for enhancement of areas with hydrothermal alteration. All the techniques used clearly show the pervasive alteration of kaolinite-argillite in the area. These alterations are mainly related to the andesite, and tuffs have the same trend as fault directions.     

A Unified Approach to Similarity Measures Between Intuitionistic Fuzzy Sets

Two general classes of similarity measures between intuitionistic fuzzy sets (hereafter IFSs) are introduced. Some properties of these measures are investigated with respect to some well‐known reasonable axioms. It is shown that several similarity measures between IFSs introduced elsewhere can be expressed by these definitions as special cases. Some illustrative and practical examples from the areas of pattern recognition, fuzzy clustering analysis, and decision making will be used to investigate the performance of the proposed measures with respect to some common measures. The results indicate that these measures can provide a useful way for measuring the degree of similarity between IFSs and that the proposed approach performs well in pattern recognition, fuzzy clustering, and decision making.     

A low-overhead scheme for testing a bit-level finite ring systolic array

Testing large VLSI circuits is a difficult and challenging problem for designers. Large unstructured circuits are often impossible to test. The number of test vectors also tend to be large and difficult to generate using automated tools for testing. In this paper, we have investigated the testing of systolic arrays built from a finite ring cell that has been proposed recently for digital signal processing functions. The cell has been shown to allow encoding, decoding and general inner product type computations for residue number system applications, with considerable advantages over equivalent binary implementation. As a further feature, we show, in this paper, that an array of such cells is remarkably easy to test for stuck-at faults. Generating test vectors for these arrays is also straightforward.     

Tolerances in self-cohering antenna arrays of arbitrary geometry

In a conventional array, the location of each element must be known to an accuracy of aboutlambda/10for phasing and scanning purposes. A larger tolerance on the element location results in the loss of gain and deterioration of the radiation pattern. In a self-cohering phased array, the phasing of the array elements is accomplished closed-loop and adaptively; therefore, no information on the element location is necessary. On the other hand, to scan the adaptively formed beam about the direction of the received wave, which has to be performed open-loop, one requires information on the element locations. In this paper, basic relations pertaining to the open-loop scanning of adaptive antenna arrays of arbitrary geometry are derived for both far-field and near-field scanning problems, and the transition between the two cases and the required accuracy in the knowledge of the same distance are explored. It is shown that the tolerance requirement on the element locations is the conventional tolerance divided by the maximum scan angle. In large systems designed for target imaging, it is shown that the tolerance on element location can be two or more orders of magnitude larger than that in a conventional array.     

Computer simulation of the effect of post annealing parameters on the microstructure inhomogeneity of the non-uniformly deformed copper

A computer simulation on the basis of the Finite Element Method and Monte Carlo Model is developed to simulate the microstructure of the non-uniformly deformed copper workpiece after annealing. Using the computer simulation, the effects of annealing time and temperature on the microstructure inhomogeneity of the workpiece are simulated and investigated quantitatively, by defining an Inhomogeneity Factor, to design an annealing program for reducing the microstructure inhomogeneity. The results show that with increasing the parameters of annealing time and temperature, the inhomogeneity is decreased when one of the parameters is constant. Also, at high annealing temperature, the annealing time changes the inhomogeneity slowly compared with which occurs at low annealing temperature. The simulation results agree well with the experimental values.     

Thickness and scratch resistance of adsorbed film formed by triblock symmetrical copolymer solutions

The thickness and scratch resistance of adsorbed films formed on mild steel samples (MS1020), which have been immersed in water copolymer solutions, are reported. The effects of bulk temperature and the copolymer structures, normal, poly(ethylene oxide)_m‐poly(propylene oxide)_n‐poly(ethylene oxide)_m, and reverse, poly(propylene oxide)_n‐poly(ethylene oxide)_m‐poly(propylene oxide)_n, are elucidated. The films' thicknesses are independent of structure but not of temperature. The adsorbed films of above cloud point solutions are thicker than below cloud point. However, nanoscratch experiments carried out to measure the scratch resistance of the films reveal that despite of thicker film formed by above cloud point solutions, it is relatively more prone to being detached than the thinner films of below cloud point solutions. The effect of extreme pressure additive, alkyl phosphate ester (APE), is also investigated suggesting the normal copolymer has comparable scratch resistance with APE when used at below the cloud point. Copyright © 2016 John Wiley & Sons, Ltd.     

Reaction sintering of nano-sized ZnO–Nb2O5 powder mixture: sintering,microstructure and microwave dielectric properties

Sintering behavior, microstructures and microwave dielectric properties of ZnNb₂O₆ (ZN) ceramics prepared by reaction-sintering method were investigated. The X-ray diffraction patterns of the sintered samples revealed single-phase formation with a columbite structure after 1–5 h sintering at 1,025–1,125 °C. After sintering at 1,125 °C for 5 h, the ZN ceramics with the density of 5.56 g/cm³ (98.9 % of the theoretical density) and good microwave dielectric properties of ε_r = 23.9, Q × f = 51,000 and τ_f = ?62 ppm/°C were obtained. The obtained results demonstrated that the reaction-sintering process is a simple and effective method to prepare the ZN ceramics for applications on microwave dielectric resonators.