Dikdörtgen şekilli mikroşerit antenlerin vekil model yöntemi ile analizi : rezonans frekansı ve bant genişliği hesabı için modelin oluşturulması ve eniyilenmesi

TEZ 621.3824/TOKdKaynakça: 40-43 ss.[Özet Yok

A novel euler chaotic map for image encryption

A novel chaotic map based on Euler number namely Euler Map (EMAP) is suggested for image encryption algorithms (IEAs). The chaotic behavior of EMAP is appreciated with bifurcation analysis and Lyapunov Exponent (LE). The LE is the best due to the ultimate and most stable characteristic in case compared with the literature. A two-stage IEA, permutation and diffusion, is used to demonstrate the successful performance of EMAP, and this is how the success of EMAP is verified. The IEA with EMAP is examined in secure cryptanalyses and computational complexity. Some results are validated with the state of the arts. In the comparison, the suggested EMAP-based IEA stands out due to the diversity and complexity performance. It achieves a cropped image having minimum loss, a good operation time of 0.2297s and a low computational complexity. Therefore, the proposed EMAP can be applied to realistic systems

An optimized surrogate model using differential evolution algorithm for computing parameters of antennas

WOS:000692850500001In this study, a method based on surrogate model (SM) for computational analysis of antenna parameters such as the resonant frequency (RF) and bandwidth (BW) is presented. Moreover, it is attempted to optimize the SM using evolutionary optimization algorithms in order to further improve the accuracy of the SM. In the conventional computational approaches, the weighting vectors of the SM have been analytically determined. We have optimally achieved the weighting vectors of the SM through differential evolution (DE) and particle swarm optimization (PSO) algorithms. The capabilities of the algorithms are hereby compared with each other. The methodology is applied to the analysis of rectangular microstrip antenna (RMA), including a number of 33 measured RMAs with different geometrical and electrical parameters. From the total number of RMAs, 27 and 6 RMAs are, respectively, used in the construction and the test of the SM. Furthermore, the SM is verified through a comparison with the literature in terms of total absolute errors (TAEs). The results show that the SM with DE computes the most accurate RF and BW with the TAEs of 0.0099 GHz and 0.131%, respectively. The accuracy of the SM is further raised by 78%, thanks to the optimization of SM with DE. Therefore, a novel computational analysis method based on SM is implemented to computation of an antenna parameter with higher accuracy, and SM is successfully optimized by DE. The proposed method is able to easily implement to the stringent engineering problems based on simulated or measured data for computer-aided design (CAD)

Surrogate-based computational analysis and design for H-shaped microstrip antenna

A conceptual Kriging surrogate model (KSM) for the computational analysis and design of H-shaped microstrip antennas (HMAs) is proposed in this study. A dataset contains 216 simulated HMAs with different physical/electrical parameters of the HMAs and the respective resonant frequency (RF) values are employed in construction and test processes of the KSM. The performance of the KSM is tested and verified through 20 and 13 HMAs by an extensive comparison with the state-of-the-art models. The results illustrate that KSM computes the most accurate RF values of 20 and 13 HMAs with absolute percent error (APE) of 0.48% and 0.76%, respectively. Moreover, a miniaturized HMA is optimally designed through the KSM as 27% smaller than the smallest design in the dataset for operating at about 2.40 GHz. Therefore, the performance of the proposed method is validated by means of the fabrication of the miniaturized HMA

Chaotic map optimization for image encryption using triple objective differential evolution algorithm

WOS:000741352800001Chaotic maps used to shuffle and manipulate the image pixels are important for image encryption (IE). In this study, a novel 2D optimized chaotic map (OPMAP) using a triple-objective differential evolution (TODE) algorithm is presented for IE. A model for OPMAP with eight decision variables is empirically designed, and then its variables are determined utilizing TODE through minimizing a triple-objective function that involving Lyapunov exponent (LE), entropy and 0-1 test. OPMAP is assessed with respect to credible measurements like bifurcation, 3D phase space, LE, 0-1 test, permutation entropy (PE) and sample entropy (SE). The capability of OPMAP is then verified through an IE scheme including permutation and diffusion through various cryptanalyses: key space 2298, mean entropy 7.9995, mean correlation 13.61E-5, number of pixels changing rate (NPCR) 99.6093, unified average changing intensity (UACI) 33.4630 and encryption processing time (EPT) 0.2919 (s). A detailed review of IE schemes reported elsewhere is presented and IE performance of OPMAP is also validated by comparison with those IE schemes with and without optimization used. The 2D-OPMAP-based IE is faster and has low computational complexity. Moreover, the proposed it shows better cryptanalysis results for the most of the comparisons

2D eπ-map for image encryption

A chaotic map generally employed to generate chaotic sequence is key element for an image encryption algorithm (IEA). In this study, an IEA using novel 2D chaotic map, which is based on Euler and Pi numbers so-called eπ-map, is presented. eπ-map exploits infinity diversity attribute of these numbers. Moreover, a diffusion operation referred to as “bit reversion” in which the bits of the pixels are symmetrically reverted is proposed for manipulating the pixel value. eπ-map is exhaustively examined through bifurcation and trajectory diagrams, Lyapunov exponent (LE), sample entropy (SE), permutation entropy (PE) and 0-1 test. The encryption performance of the IEA is then investigated across various cryptanalysis such as key-space, key sensitivity, histogram, information entropy, correlation coefficient, differential attack, cropping attack, noise attack and encryption execution time. Furthermore, the results are compared with the most recent literature. It is demonstrated that eπ-map has superior hyperchaotic performance in views of ergodicity, complexity and randomness. The IEA based on eπ-map and bit reversion is a secure and reliable algorithm thanks to its outperforming cryptanalysis results

An UWB antenna design having band-reject characteristic by y-hhaped strip

23rd International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) -- SEP 24-27, 2018 -- Tbilisi, GEORGIAWOS:000468985000037In this study, an ultra-wide band (UWB) antenna having band-notched operation for WLAN application has been designed. To model the antenna design, HyperLynx (R) 3D electromagnetic simulation program is used. The UWB antenna operates between the frequencies of 2.5 GHz and 11 GHz. To obtain the ideal rejecting characteristic over the desired frequency band, a Y-shaped strip is added into the full UWB antenna radiator. Thus, a frequency rejection response is obtained in band range of 5.0 GHz and 6.0 GHz for WLAN application. By changing the size of the Y-shaped strip, not only center frequency for interval 5 GHz and 6 GHz but also rejected bandwidth can be readily shifted. As a result, A suitable notch characteristic is achieved for desired band thanks to optimized strip geometry.IEEE, IEEE Microwave Theory & Tech Soc, IEEE Electron Devices Soc, IEEE Antennas & Propagat Soc, Univ Tphilisensis, Ivane Javakhishvili Tbilisi State Univ, NASU, Pidstryhach Inst Appl Problems Mech & Math, IEEE MTT ED AP Georgia Chapter, IEEE Ukraine Sect W MTT ED AP EP SSC Soc Joint Chapter, IEEE Ukraine Sect, IEEE Elect Packaging Soc, IEEE Solid State Circuits So

A new Pi-based chaotic map for ımage encryption

Novel chaotic map (CM) based on pi number socalled Pi-map is introduced for image encryption scheme (ImES). The chaotic behavior of the Pi-map is appreciated with respect to Lyapunov Exponent (LE) and bifurcation graphs. The LE which is stable and highest is also compared those reported elsewhere. The image encryption performance of Pi-map is corroborated on a simple ImES consisting of only two operations which are permutation and diffusion. The ImES with Pi-map is crypto-studied through various analysis and, they are even crosschecked with the others in the literature. It is shown that ImES is eminent and reliable thanks to the capability of the Pi-map regarding randomness and complexness