In this paper, a modified firefly algorithm (MFA) is proposed to find the optimal multilevel threshold values for color image. Kapur's entropy, minimum cross entropy and between-class variance method is used as th...
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In this paper, a modified firefly algorithm (MFA) is proposed to find the optimal multilevel threshold values for color image. Kapur's entropy, minimum cross entropy and between-class variance method is used as the objective functions. To test and analyze the performance of the MFA algorithm, the presented method are tested on ten test color image and the results are compared with basic firefly algorithm (FA), Brownian search based firefly algorithm (BFA) and Levy search based firefly algorithm (LFA). The experimental results show that the presented MFA algorithm outperforms all the other algorithms in term of the optimal threshold value, objective function, PSNR, SSIM value and convergence. In MFA algorithm, chaotic map is used to the initialization of firefly population, which can enhance the diversification. In addition, global search method of particle swarm optimization (PSO) algorithm is introduced into the movement phase of fireflies. Compared with the other methods, the MFA algorithm is an effective method for multilevel color image thresholding segmentation. (C) 2017 Elsevier B.V. All rights reserved.
Significant energy savings can be achieved by optimizing chiller operation and design in heating, ventilation and cooling (HVAC) systems. In terms of optimization, various metaheuristics have been proposed to the opti...
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Significant energy savings can be achieved by optimizing chiller operation and design in heating, ventilation and cooling (HVAC) systems. In terms of optimization, various metaheuristics have been proposed to the optimal chiller loading problem. New metaheuristics are also emerging recently, between them the firefly algorithm. firefly algorithm is a nature inspired algorithm based on the idealized behavior of the flash pattern and characteristics of fireflies. This study proposes a new improved firefly algorithm (IFA) based on Gaussian distribution function to the optimal chiller loading design. To testify the performance of the proposed method, the paper adopts two case studies comparing the results of the developed model using IFA with those of traditional firefly algorithm and other optimization methods in literature. In this paper, the optimization problem is minimize energy consumption of multi-chiller systems, where the objective function is energy consumption and the optimum parameter is the partial loading ratio of each chiller. The results of both case studies show that the proposed IFA outperform several optimization methods of the literature in terms of minimum energy consumption solution of the optimal chiller loading problem. (C) 2013 Elsevier B.V. All rights reserved.
To design the tunnel excavations, the most important parameters are the engineering properties of rock, e.g., Young's modulus (E) and unconfined compressive strength (UCS). Numerous researchers have attempted to p...
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To design the tunnel excavations, the most important parameters are the engineering properties of rock, e.g., Young's modulus (E) and unconfined compressive strength (UCS). Numerous researchers have attempted to propose methods to estimate E and UCS indirectly. This task is complex due to the difficulty of preparing and carrying out such experiments in a laboratory. The main aim of the present study is to propose a new and efficient machine learning model to predict E and UCS. The proposed model combines the extreme gradient boosting machine (XGBoost) with the firefly algorithm (FA), called the XGBoost-FA model. To verify the feasibility of the XGBoost-FA model, a support vector machine (SVM), classical XGBoost, and radial basis function neural network (RBFN) were also employed. Forty-five granite sample sets, collected from the Pahang-Selangor tunnel, Malaysia, were used in the modeling. Several statistical functions, such as coefficient of determination (R-2), mean absolute percentage error (MAPE) and root mean square error (RMSE) were calculated to check the acceptability of the methods mentioned above. A review of the results of the proposed models revealed that the XGBoost-FA was more feasible than the others in predicting both E and UCS and could generalize.
The current study deals with the optimization of significant parameters of aluminium and copper rectangular porous fins using firefly algorithm with reflective boundary condition. The study has been done considering c...
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The current study deals with the optimization of significant parameters of aluminium and copper rectangular porous fins using firefly algorithm with reflective boundary condition. The study has been done considering convective heat transfer, in the first case, as well as combined convective and radiative modes of heat transfer, in the second case. To solve the non-linear governing equation, a semi analytical technique, differential transformation method is adopted. The results obtained by differential transformation method are validated by the numerical solution obtained by the finite difference method. The performance of firefly algorithm is evaluated by comparing with the results obtained by particle swarm optimization where it is seen that for the current set of equations, firefly algorithm took lesser number of iterations and computational time to converge than particle swarm optimization for all the cases. The analysis has been done for three different fin volumes and the effect of important variables which directly influence the heat transfer rate through porous fins has been discussed.
Hydraulic jumps can occur downstream of hydraulic structures, such as normal weirs, gates and ogee spillways. The roller length is one of the most important parameters of hydraulic jumps in open channels. In this stud...
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Hydraulic jumps can occur downstream of hydraulic structures, such as normal weirs, gates and ogee spillways. The roller length is one of the most important parameters of hydraulic jumps in open channels. In this study, the roller length of a hydraulic jump on a rough bed is predicted using a hybrid of adaptive neuro-fuzzy inference systems and the firefly algorithm (ANFIS-FA). First, the effect of parameters including the Froude number (Fr), sequent depth (h (2)/h (1)) and relative roughness (ks/h (1)) upstream of a hydraulic jump is studied. Following the modeling result analysis, ANFIS-FA is introduced as the superior model for estimating the roller length of a hydraulic jump on a rough bed according to Fr, h (2)/h (1) and ks/h (1). The calculated MAPE, RMSE and correlation coefficient values for the superior model are 7.606, 1.771 and 0.970, respectively. ANFIS-FA predicted approximately 40 % of the results with less than 5 % error, and only 36 % of data had more than 10 % error.
In this study, a recently developed metaheuristic optimization algorithm, the firefly algorithm (FA), is used for solving mixed continuous/discrete structural optimization problems. FA mimics the social behavior of fi...
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In this study, a recently developed metaheuristic optimization algorithm, the firefly algorithm (FA), is used for solving mixed continuous/discrete structural optimization problems. FA mimics the social behavior of fireflies based on their flashing characteristics. The results of a trade study carried out on six classical structural optimization problems taken from literature confirm the validity of the proposed algorithm. The unique search features implemented in FA are analyzed, and their implications for future research work are discussed in detail in the paper. (C) 2011 Elsevier Ltd. All rights reserved.
This paper presents a novel hybrid algorithm combining firefly algorithm (FA) and Nelder Mead (NM) simplex method for solving power system Optimal Reactive Power Dispatch (ORPD) problems. The ORPD is a very important ...
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This paper presents a novel hybrid algorithm combining firefly algorithm (FA) and Nelder Mead (NM) simplex method for solving power system Optimal Reactive Power Dispatch (ORPD) problems. The ORPD is a very important aspect of power system operation and is a highly nonlinear, non-convex optimization problem, consisting of both continuous and discrete control variables. Like many other general purpose optimization methods, the original FA often traps into local optima and in order to overcome the shortcoming, in this paper, an efficient local search method called NM simplex subroutine is introduced in the internal architecture of the original FA algorithm. The proposed Hybrid firefly algorithm (HFA) avoids premature convergence of original FA by exploration with FA and exploitation with NM simplex. The proposed method is applied to determine optimal settings of generator voltages, tap positions of tap changing transformers and VAR output of shunt capacitors to optimize two different objective functions;such as minimization of real power loss and voltage deviations. The program is developed in Matlab and the proposed hybrid algorithm is examined on two standard IEEE test systems for solving the ORPD problems. For validation purpose, the results obtained with the proposed approach are compared with those obtained by other methods. It is observed that the proposed method has better convergence characteristics and robustness compared to the original version of FA and other existing methods. It is revealed that the proposed hybrid method is able to provide better solutions. (C) 2014 Elsevier Ltd. All rights reserved.
The computation procedure for structural shape optimization is based on the heuristic optimization procedures, such as swarm intelligence (SI), that use patterns found in self-organizing phenomena observed in nature. ...
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The computation procedure for structural shape optimization is based on the heuristic optimization procedures, such as swarm intelligence (SI), that use patterns found in self-organizing phenomena observed in nature. Most SI techniques including particle swarm optimization (PSO) and artificial bee colony (ABC), attain a global optimal solution. The firefly algorithm (FA) can attain both a global optimal and local optimal solutions by setting suitable computational parameters. However, the method for setting these parameters is comparatively difficult. In order to simplify the setting of these parameters, we implement a computational scheme where the distance between two fireflies in the design variable space is dimensionless. The effectiveness and the validity of this FA are clarified by showing the diversified solution for a global optimal solution and local optimal solutions using a local search in the structural shape optimization of a free-form surface shell.
In this research, we propose a variant of the firefly algorithm (FA) for classifier ensemble reduction. It incorporates both accelerated attractiveness and evading strategies to overcome the premature convergence prob...
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In this research, we propose a variant of the firefly algorithm (FA) for classifier ensemble reduction. It incorporates both accelerated attractiveness and evading strategies to overcome the premature convergence problem cif the original FA model. The attractiveness strategy takes not only the neighboring but also global best solutions into account, in order to guide the firefly swarm to reach the optimal regions with fast convergence while the evading action employs both neighboring and global worst solutions to drive the search out of gloomy regions. The proposed algorithm is subsequently used to conduct discriminant base classifier selection for generating optimized ensemble classifiers without compromising classification accuracy. Evaluated with standard, shifted, and composite test functions, as well as the Black-Box Optimization Benchmarking test suite and several high dimensional UCI data sets, the empirical results indicate that, based on statistical tests, the proposed FA model outperforms other state-of-the-art FA variants and classical metaheuristic search methods in solving diverse complex unimodal and multimodal optimization and ensemble reduction problems. Moreover, the resulting ensemble classifiers show superior performance in comparison with those of the original, full-sized ensemble models. (C) 2017 Elsevier Ltd. All rights reserved.
The cut-off distance of the density peaks clustering (DPC) algorithm need to be set manually;the two local densities of the algorithm have a large difference in the clustering effect on the same dataset. To address th...
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The cut-off distance of the density peaks clustering (DPC) algorithm need to be set manually;the two local densities of the algorithm have a large difference in the clustering effect on the same dataset. To address the issue, the paper proposes an improved DPC based on firefly algorithm. It combines the cut-off kernel and the Gaussian kernel defined by the DPC algorithm, and balances the effects of the two kernels by the weighting factor. Meanwhile, a cluster-like centre evaluation criterion based on local density and relative distance of preference coefficient is constructed. In order to determine the parameters of the cut-off distance, weighting factor and preference coefficient, the three parameters are optimised by the firefly algorithm with the Rand index as the objective function. The experiment results show that the performance of the proposed method on synthetic datasets and real datasets is better than DPC and its variants.
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