A novel bat flower pollination algorithm for synthesis of linear antenna arrays

In this paper, a novel algorithm, namely bat flower pollination (BFP) is proposed for synthesis of unequally spaced linear antenna array (LAA). The new method is a combination of bat algorithm (BA) and flower pollination algorithm (FPA). In BFP, both BA and FPA interact with each other to escape from local minima. The results of BFP for solving a set of 13 benchmark functions demonstrate its superior performance as compared to variety of well-known algorithms available in the literature. The novel proposed method is also used for the synthesis of unequally spaced LAA for single and multi-objective design. Simulation results show that BFP is able to provide better synthesis results than wide range of popular techniques like genetic algorithm, differential evolution, cuckoo search, particle swarm optimization, back scattering algorithm and others.

     

Design optimization of circular antenna arrays using Taguchi method

This paper presents the application of Taguchi method (TM) to design optimization of non-uniform circular antenna array (CAA) for suppression of sidelobe levels (SLLs). TM, a robust design approach, takes signal-to-noise ratio and orthogonal array tools from the statistical design of experiments. These tools allow instead of full factorial parametric analysis minimize the design parameters; thus, increase the convergence speed and generate more accurate solutions. TM is used to determine an optimal set of amplitudes and positions of CAA for 8, 10, and 12 elements. Comparison of the results of the TM with those of latest meta-heuristic algorithms in the literature reveals that the CAA design with TM provides the best SLL reduction performance in all cases.

     

Application of mutation operators to flower pollination algorithm

Flower pollination algorithm (FPA) is a recent addition to the field of nature inspired computing. The algorithm has been inspired from the pollination process in flowers and has been applied to a large spectra of optimization problems. But it has certain drawbacks which prevents its applications as a standard algorithm. This paper proposes new variants of FPA employing new mutation operators, dynamic switching and improved local search. A comprehensive comparison of proposed algorithms has been done for different population sizes for optimizing seventeen benchmark problems. The best variant among these is adaptive-Lévy flower pollination algorithm (ALFPA) which has been further compared with the well-known algorithms like artificial bee colony (ABC), differential evolution (DE), firefly algorithm (FA), bat algorithm (BA) and grey wolf optimizer (GWO). Numerical results show that ALFPA gives superior performance for standard benchmark functions. The algorithm has also been subjected to statistical tests and again the performance is better than the other algorithms.     

t-分布扰动策略和变异策略的花授粉算法

为了解决传统花授粉算法(FPA)收敛速度慢、易陷入局部最优、寻优精度低等缺陷,提出了一种t-分布扰动策略和变异策略的花授粉算法(t MFPA).首先利用混沌映射初始化花朵个体的位置,然后在全局授粉过程中,利用t-分布扰动的随机个体和莱维飞行共同实现个体位置更新,加快收敛速度的同时提高搜索空间的多样性;在局部授粉过程中,加入具有两个差分向量的变异策略和小概率策略,结合两种策略使算法能够跳出局部最优.实验结果表明,t MFPA相比于FPA和其他启发式智能算法具有更好的寻优精度和收敛速度,相对于其他改进算法具有更好的收敛性能.     

混合花粉算法求解全局优化问题

元启发式算法可以用作寻找近似最优解的有效工具,因此,对元启发式算法进行改进,提高算法性能是有必要的。本文介绍花粉算法(Flower Pollination Algorithm, FPA)的增强变体,将花粉算法与极值优化算法(Extremal Optimization, EO)混合形成FPA-EO算法。FPA-EO算法综合利用了FPA的全局搜索能力和EO的局部搜索能力,并将其应用于11个基准测试函数来测试新算法。同时将该算法与其他4种著名优化算法（标准花粉算法(FPA)、蝙蝠算法(BAT)、萤火虫算法(FA)、模拟退火算法(SA)）进行比较。综合结果表明,本文算法能够找到比其他4种算法更精确的解。     

多策略增强花授粉算法及其应用

针对经典花授粉算法容易陷入局部最优解和收敛速度慢的缺点,提出一种增强型透镜成像策略和随机邻域变异策略的花授粉算法。通过增强型透镜成像策略扩展花授粉算法的搜索空间,增加解的多样性,有助于算法跳出局部最优解。引入随机邻域变异策略,借助邻域内的信息指导算法搜索,增强算法的收敛精度和搜索速度。对改进后的花授粉算法和四种其他改进算法在CEC2013测试函数上进行比较,实验证明改进后的多策略花授粉算法不论是收敛精度还是搜索速度都比对比算法优秀。最后把多策略花授粉算法应用在汽车传动参数模型上研究该算法的实际效用,结果表明多策略花授粉算法在汽车传动参数优化问题上都优于对比算法。     

Design of planar concentric circular antenna arrays with reduced side lobe level using symbiotic organisms search

This paper investigates the design of concentric circular antenna arrays (CCAAs) with optimum side lobe level reduction using the Symbiotic Organisms Search (SOS) algorithm. Both thinned and full CCAAs are considered. SOS represents a rather new evolutionary algorithm for antenna array optimization. SOS is inspired by the symbiotic interaction strategies between different organisms in an ecosystem. SOS uses simple expressions to model the three common types of symbiotic relationships: mutualism, commensalism, and parasitism. These expressions are used to find the global minimum of the fitness function. Unlike other methods, SOS is free of tuning parameters, which makes it an attractive optimization method. The results obtained using SOS are compared to those obtained using several optimization methods, like Biogeography-Based Optimization (BBO), Teaching-Learning-Based Optimization (TLBO), and Evolutionary Programming (EP). It is shown that the SOS is a robust straightforward evolutionary algorithm that competes with other known methods.

     

Circular antenna array synthesis using firefly algorithm

In this article, the design of circular antenna arrays (CAAs) and concentric circular antenna arrays (CCAAs) of isotropic radiators with optimum side lobe level (SLL) reduction is studied. The newly proposed global evolutionary optimization method; namely, the firefly algorithm (FA) is used to determine an optimum set of weights and positions for CAAs, and an optimum set of weights for CCAAs, that provides a radiation pattern with optimum SLL reduction with the constraint of a fixed major lobe beamwidth. The FA represents a new algorithm for optimization problems in electromagnetics. It is shown that the FA results provide a SLL reduction that is better than that obtained using well‐known algorithms, like the particle swarm optimization, genetic algorithm (GA), and evolutionary programming. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:139–146, 2014.     

Synthesis of thinned concentric circular antenna arrays using teaching‐learning‐based optimization

In this article, the design of thinned concentric circular antenna arrays (CCAAs) of isotropic radiators with optimum side lobe level (SLL) reduction is studied. The newly proposed global evolutionary optimization method; namely, the teaching‐learning‐based optimization (TLBO) is used to determine an optimum set of turned ON elements of thinned CCAAs that provides a radiation pattern with optimum SLL reduction. The TLBO represents a new algorithm for optimization problems in electromagnetics and antennas. It is shown that the TLBO provides results that are somewhat better than those obtained using other evolutionary algorithms, like the firefly algorithm and biogeography based optimization. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:443–450, 2014.     

Optimization of circular antenna arrays using the cuckoo search algorithm

This article presents a study of circular antenna array design and optimization using the cuckoo search (CS) algorithm. The goal of optimization is to minimize the maximum sidelobe level with and without null steering. The CS algorithm is used to determine the parameters of the array elements that produce the desired radiation pattern. We illustrated the effectiveness of the CS in the design and optimization of circular antenna arrays by means of extensive numerical simulations. We compared our results with other methods from the literature whenever possible. We presented numerous examples that show the excellent performance and robustness of the CS algorithm and the results reveal that the design of circular antenna arrays using the CS algorithm provides acceptable enhancement compared with the uniform array or the design obtained using other optimization methods.     

Accelerated biogeography-based optimization with neighborhood search for optimization

Biogeography-based optimization (BBO) inherently lacks exploration capability that leads to slow convergence. To address this limitation, authors present a memetic algorithm (MA) named as aBBOmDE, which is a new variant of BBO. In aBBOmDE, the performance of BBO is accelerated with the help of a modified mutation and clear duplicate operators. Then modified DE (mDE) is embedded as a neighborhood search operator to improve the fitness from a predefined threshold. mDE is used with mutation operator DE/best/1/bin to explore the search near the best solution. The length of local search is a choice that balances between the search capability and the computational cost. In aBBOmDE, migration mechanism is kept same as that of BBO in order to maintain its exploitation ability. Modified operators are utilized to enhance the exploration ability while a neighborhood search operator further enhances the search capability of the algorithm. This combination significantly improves the convergence characteristics of the original algorithm. Extensive experiments have been carried out on forty benchmark functions to show the effectiveness of the proposed algorithm. The results have been compared with original BBO, DE, CMAES, other MA and DE/BBO, a hybrid version of DE and BBO. aBBOmDE is also applied to compute patch dimensions of rectangular microstrip patch antennas (MSAs) with various substrate thicknesses so as to be used a CAD formula for antenna design.     

基于单纯形法和自适应步长的花朵授粉算法

针对花朵授粉算法易陷入局部极值、后期收敛速度慢的不足,提出一种基于单纯形法和自适应步长的花朵授粉算法。该算法在基本花朵授粉算法的全局寻优部分采用自适应步长策略来更新个体位置,步长随迭代次数的增加而自适应地调整,避免局部极值;在局部寻优部分对进入下一次迭代的部分较差个体采用单纯形法的扩张、收缩/压缩操作,提高局部搜索能力,进而提高算法的寻优能力。通过八个CEC2005benchmark测试函数进行测试比较,结果表明,改进算法的寻优性能明显优于基本的花朵授粉算法,且其收敛速度、收敛精度、鲁棒性均较对比算法有较大提高。     

Color image quantization using flower pollination algorithm

Flower pollination algorithm (FPA) is a swarm-based optimization technique that has attracted the attention of many researchers in several optimization fields due to its impressive characteristics. This paper proposes a new application for FPA in the field of image processing to solve the color quantization problem, which is use the mean square error is selected as the objective function of the optimization color quantization problem to be solved. By comparing with the K-means and other swarm intelligence techniques, the proposed FPA for Color Image Quantization algorithm is verified. Computational results show that the proposed method can generate a quantized image with low computational cost. Moreover, the quality of the image generated is better than that of the images obtained by six well-known color quantization methods.

     

Power-pattern synthesis for energy beamforming in wireless power transmission

This paper proposed a power-pattern optimization method for suppressing the maximum side lobe level outside of the collection region (CSL) of energy beamforming for wireless power transmission based on the biogeography-based optimization with local search (BBOLS). Two improved components, local search operator and selection operator, are introduced into the normal biogeography-based optimization to improve the performance of the algorithm. These two introduced factors can significantly help the algorithm to improve the convergence rate, prevent the candidate solutions from being trapped into the local optimum. Simulation results show that the CSL of the planar antenna array obtained by BBOLS can be depressed effectively while the beam collection efficiency can be enhanced. Moreover, the accuracy and the convergence rate of BBOLS are better than other algorithms. In addition, the power-pattern performance obtained by BBOLS is also verified by the electromagnetic simulations.

     

Cells to Switches Assignment in Cellular Mobile Networks Using Metaheuristics

Cabling, handoff, and switching costs play pivotal roles in the design and development of cellular mobile networks. The assignment pattern consisting of which cell is to be connected to which switch can have a significant impact on the individual cost. In the presence of the limitation on the number of cells that can be assigned to a switch, the problem of the cell to switch assignment (CSA) becomes nondeterministic polynomial time hard to solve with all effective solutions being based on metaheuristic optimization algorithms (MOA) approach. This article applies three recently evolved MOA, namely, flower pollination algorithm (FPA), hunting search (HuS), and wolf search algorithm (WSA) for solving CSA problem. Comprehensive computational experiments conducted to collate the performance of the three algorithms indicate that FPA is superior to both HuS and WSA with respect to attaining the global best value and faster convergence with desired CSA.     

Enhancing the performance of biogeography-based optimization using polyphyletic migration operator and orthogonal learning

Biogeography-based optimization (BBO) is a powerful population-based algorithm inspired by biogeography and has been extensively applied to many science and engineering problems. However, its direct-copying-based migration and random mutation operators make BBO possess local exploitation ability but lack global exploration ability. To remedy the defect and enhance the performance of BBO, an enhanced BBO variant, called POLBBO, is developed in this paper. In POLBBO, a proposed efficient operator named polyphyletic migration operator can formally utilize as many as four individuals’ features to construct a new solution vector. This operator cannot only generate new features from more promising areas in the search space, but also effectively increase the population diversity. On the other hand, an orthogonal learning (OL) strategy based on orthogonal experimental design is employed. The OL strategy can quickly discover more useful information from the search experiences and efficiently utilize the information to construct a more promising solution, and thereby provide a systematic and elaborate reasoning method to guide the search directions of POLBBO. The proposed POLBBO is verified on a set of 24 benchmark functions with diverse complexities, and is compared with the basic BBO, five state-of-the-art BBO variants, five existing OL-based algorithms, and nine other evolutionary algorithms. The experimental results and comparisons demonstrate that the polyphyletic migration operator and the OL strategy can work together well and enhance the performance of BBO significantly in terms of the quality of the final solutions and the convergence rate.     

融合正弦余弦算法和精英算子的花授粉算法

针对花授粉算法（FPA）具有寻优精度较低,稳定性不高的问题,提出了一种融合正弦余弦算法和精英算子的花授粉算法（SCA-EFPA）。针对花授粉算法的局部授粉过程,授粉范围小且易陷入局部最优值的问题,利用正弦余弦算法的“局部开发”和“全局搜索”特性,并作简化改进后引入;针对其全局授粉过程,搜索范围较大且寻优精度低的问题,引入精英花粉算子以提高寻优精度并且进行变异和交叉操作以保持种群多样性。达到整个改进后的算法具有提高寻优精度的目的。选取多组标准测试函数来测试改进算法的各项性能。结果表明,与基本花授粉算法、粒子群算法和差分变异算法等相比,融合正弦余弦算法和精英算子的花授粉算法具有更高的寻优精度,更好的稳定性和收敛性。     

Empirical analysis of five nature-inspired algorithms on real parameter optimization problems

In the past few years nature-inspired algorithms are seen as potential tools to solve computationally hard problems. Tremendous success of these algorithms in providing near optimal solutions has inspired the researchers to develop new algorithms. However, very limited efforts have been made to identify the best algorithms for diverse classes of problems. This work attempts to assess the efficacy of five contemporary nature-inspired algorithms i.e. bat algorithm (BA), artificial bee colony algorithm (ABC), cuckoo search algorithm (CS), firefly algorithm (FA) and flower pollination algorithm (FPA). The work evaluates the performance of these algorithms on CEC2014 30 benchmark functions which include unimodal, multimodal, hybrid and composite problems over 10, 30, 50 and 100 dimensions. Control parameters of all algorithms are self-adapted so as to obtain best results over benchmark functions. The algorithms have been evaluated along three perspectives (a) statistical significance using Wilcoxon rank sum test (b) computational time complexity (c) convergence rate of algorithms. Experimental results and analysis revealed that ABC algorithm perform best for majority of the problems on high dimension, while on small dimension, CS is the best choice. FPA attain the next best position follow by BA and FA for all kinds of functions. Self adaptation of above algorithms also revealed the best values of input parameters for various algorithms. This study may aid experts and scientists of computational intelligence to solve intricate optimization problems.     

A hybrid biogeography-based optimization algorithm for job shop scheduling problem

In this paper, a hybrid biogeography-based optimization (HBBO) algorithm has been proposed for the job-shop scheduling problem (JSP). Biogeography-based optimization (BBO) is a new bio-inpired computation method that is based on the science of biogeography. The BBO algorithm searches for the global optimum mainly through two main steps: migration and mutation. As JSP is one of the most difficult combinational optimization problems, the original BBO algorithm cannot handle it very well, especially for instances with larger size. The proposed HBBO algorithm combines the chaos theory and “searching around the optimum” strategy with the basic BBO, which makes it converge to global optimum solution faster and more stably. Series of comparative experiments with particle swarm optimization (PSO), basic BBO, the CPLEX and 14 other competitive algorithms are conducted, and the results show that our proposed HBBO algorithm outperforms the other state-of-the-art algorithms, such as genetic algorithm (GA), simulated annealing (SA), the PSO and the basic BBO.     

Low-sidelobe marine radar microstrip array antenna based on hybrid algorithm and metamaterial

A microstrip array antenna with low sidelobe level (SLL) for X-band marine radar is proposed. The antenna is composed of a 32-element patch array and a three-layer near-zero-index metamaterial (NZIM). The IABC-Kmeans algorithm, which combines the improved artificial bee colony algorithm and K-means clustering algorithm, is used to optimize the current amplitude of the array elements to obtain a lower SLL. The NZIM is loaded in front of the array antenna to reduce the beamwidth of the E-plane. The antenna is designed and fabricated. The measurement results show that the gain of the antenna at the center frequency is 22.7 dBi, the SLLs of H-plane and E-plane are ?30.66 dB and ? 26.78 dB respectively, and the half-power beamwidth of H-plane is 5.9°. Compared with the previous similar antenna structures, the antenna has lower SLL under the premise of narrow beam and high gain, which is very suitable for X-band marine radar of small and medium fishing vessels.