scholarly journals Optimal Unimodular Sequences Design Method for Active Sensing Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ze Li ◽  
Ping Li ◽  
Xinhong Hao ◽  
Xiaopeng Yan

In active sensing systems, unimodular sequences with low autocorrelation sidelobes are widely adopted as modulation sequences to improve the distance resolution and antijamming performance. In this paper, in order to meet the requirements of specific practical engineering applications such as suppressing certain correlation coefficients and finite phase, we propose a new algorithm to design both continuous phase and finite phase unimodular sequences with a low periodic weighted integrated sidelobe level (WISL). With the help of the transformation matrix, such an algorithm decomposes the N-dimensional optimization problem into N one-dimensional optimization problems and then uses the iterative method to search the optimal solutions of the N one-dimensional optimization problems directly. Numerical experiments demonstrate the effectiveness and the convergence property of the proposed algorithm.

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1800
Author(s):  
Mengjian Zhang ◽  
Daoyin Long ◽  
Tao Qin ◽  
Jing Yang

In order to solve the problem that the butterfly optimization algorithm (BOA) is prone to low accuracy and slow convergence, the trend of study is to hybridize two or more algorithms to obtain a superior solution in the field of optimization problems. A novel hybrid algorithm is proposed, namely HPSOBOA, and three methods are introduced to improve the basic BOA. Therefore, the initialization of BOA using a cubic one-dimensional map is introduced, and a nonlinear parameter control strategy is also performed. In addition, the particle swarm optimization (PSO) algorithm is hybridized with BOA in order to improve the basic BOA for global optimization. There are two experiments (including 26 well-known benchmark functions) that were conducted to verify the effectiveness of the proposed algorithm. The comparison results of experiments show that the hybrid HPSOBOA converges quickly and has better stability in numerical optimization problems with a high dimension compared with the PSO, BOA, and other kinds of well-known swarm optimization algorithms.


2018 ◽  
Vol 65 (5) ◽  
pp. 506-514 ◽  
Author(s):  
Khalid Rashid ◽  
Anees Khadom

PurposeThe purpose of this study is to investigate the corrosion inhibition of mild steel alloy in 2 M H3PO4solution by the pomegranate peel extract as a friendly inhibitor was studied at various temperatures, inhibitor concentrations and immersion times.Design/methodology/approachA weight loss method was used to evaluate the corrosion rate. The experimental Taguchi design method was used for the distribution of experiments. The experimental design gave results which were impossible to show graphically. However, this problem was solved effectively with the aid of regression analysis.FindingsCorrosion rate increased with temperature according to Arrhenius equation. It was found that the efficiency of inhibition was increased with an increase in the concentration of inhibitor and immersion time. However, this diminishes with increased temperature. According to Langmuir isotherm, the inhibitor was adsorbed physically on steel surface. The negative sign of estimated heat of adsorption suggests a stable spontaneous inhibition process. Combination of mathematical and statistical analysis was proposed to demonstrate the results of corrosion rate with high correlation coefficients. In addition, Fourier transform infrared spectrometer examinations confirmed that the organic inhibitor consists of phenolic components as main materials.Originality/valueUsing unconventional approach for evaluation of environmentally friendly inhibitor for corrosion of mild steel in phosphoric acid solution.


2020 ◽  
pp. 1-14
Author(s):  
Nita H. Shah ◽  
Poonam Prakash Mishra

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