Hybrid bee colony optimization for examination timetabling problems

Swarm intelligence is a branch of artificial intelligence that focuses on the actions of agents in self-organized systems. Researchers have proposed a bee colony optimization (BCO) algorithm as part of swarm intelligence. BCO is a meta-heuristic algorithm based on the foraging behavior of bees. This study presents a hybrid BCO algorithm for examination timetabling problems. Bees in the BCO algorithm perform two main actions: forward pass and backward pass. Each bee explores the search space in forward pass and then shares information with other bees in the hive in backward pass. This study found that a bee decides to be either a recruiter that searches for a food source or a follower that selects a recruiter bee to follow on the basis of roulette wheel selection. In forward pass, BCO is supported along with other local searches, including the Late Acceptance Hill Climbing and Simulated Annealing algorithms. We introduce three selection strategies (tournament, rank and disruptive selection strategies) for the follower bees to select a recruiter to maintain population diversity in backward pass. The disruptive selection strategy outperforms tournament and rank selections. We also introduce a self-adaptive mechanism to select a neighborhood structure to enhance the neighborhood search. The proposed algorithm is evaluated against the latest methodologies in the literature with respect to two standard examination timetabling problems, namely, uncapacitated and competition datasets. We demonstrate that the proposed algorithm produces one new best result on uncapacitated datasets and comparable results on competition datasets.     

An enhanced artificial bee colony algorithm with adaptive differential operators

Artificial bee colony algorithm (ABC) has been shown to be very effective to solve global optimization problems (GOPs). However, ABC performs well in exploration but relatively poorly in exploitation resulting in a slow convergence when it is used to handle complex GOPs. Differential evolution (DE) benefits from its differential operators, namely mutation operator and crossover operator, which could perturb multiple variables simultaneously and has shown a fast convergence speed. In order to improve ABC’s exploitation ability and accelerate its convergence, in this paper, we propose an enhanced ABC algorithm named ABCADE, which remedy the limitation of ABC by exploiting the advantage of differential operators. Particularly, in ABCADE, the employed bees employ differential operators to produce candidate solutions with an increasing probability, and the two important parameters (scale factor F and crossover rate CR) of differential operators are adaptively adjusted through Gaussian distribution. Moreover, to significantly differentiate the good solutions and bad solutions in a population, and put more effort in the exploitation around the good solutions, we design a new selection probability method for onlooker bees. To verify the performance of ABCADE, we compare ABCADE with other representative state-of-the-art ABC and DE algorithms, the comparison results on a set of 22 benchmark functions with various dimension sizes demonstrate that ABCADE obtains superior or comparable performance to other algorithms.     

具有自适应趋向性和引导因子的人工蜂群算法

针对人工蜂群算法中存在的收敛速度慢、寻优精度低的问题,提出了一种改进的人工蜂群算法。该算法将自适应趋向性加入雇佣蜂的搜索方案中,同时在观察蜂的搜索方案中加入引导因子。通过雇佣蜂对优秀蜜源的动态趋向搜索以及观察蜂在引导因子引领下的协同搜索,显著提高了算法的局部搜索能力。基于八个标准测试函数的仿真结果表明,与基本人工蜂群算法相比,改进后的算法在寻优精度和收敛速度方面均有明显提升。     

An adaptive and hybrid artificial bee colony algorithm (aABC) for ANFIS training

In this study, we propose an Adaptive and Hybrid Artificial Bee Colony (aABC) algorithm to train ANFIS. Unlike the standard ABC algorithm, two new parameters are utilized in the solution search equation. These are arithmetic crossover rate and adaptivity coefficient. aABC algorithm gains the rapid convergence feature with the usage of arithmetic crossover and it is applied on two different problem groups and its performance is measured. Firstly, it is performed over 10 numerical ‘benchmark functions’. The results show that aABC algorithm is more efficient than standard ABC algorithm. Secondly, ANFIS is trained by using aABC algorithm to identify the nonlinear dynamic systems. Each application begins with the randomly selected initial population and then average RMSE is obtained. For four examples considered in ANFIS training, train error values are respectively computed as 0.0344, 0.0232, 0.0152 and 0.0205. Also, test error values for these examples are respectively found as 0.0255, 0.0202, 0.0146 and 0.0295. Although it varies according to the examples, performance increase between 4.51% and 33.33% occurs. Additionally, it is seen that aABC algorithm converges bettter than ABC algorithm in the all examples. The obtained results are compared with the neuro-fuzzy based approaches which are commonly used in the literature and it is seen that the proposed ABC variant can be efficiently used for ANFIS training.     

An adaptive artificial bee colony algorithm based on objective function value information

Artificial bee colony (ABC) algorithm is a novel biological-inspired optimization algorithm, which has many advantages compared with other optimization algorithm, such as less control parameters, great global optimization ability and easy to carry out. It has proven to be more effective than some evolutionary algorithms (EAs), particle swarm optimization (PSO) and differential evolution (DE) when testing on both benchmark functions and real issues. ABC, however, its solution search equation is poor at exploitation. For overcoming this insufficiency, two new solution search equations are proposed in this paper. They apply random solutions to take the place of the current solution as base vector in order to get more useful information. Exploitation is further improved on the basis of enhancing exploration by utilizing the information of the current best solution. In addition, the information of objective function value is introduced, which makes it possible to adjust the step-size adaptively. Owing to their respective characteristics, the new solution search equations are combined to construct an adaptive algorithm called MTABC. The methods our proposed balance the exploration and exploitation of ABC without forcing severe extra overhead in respect of function evaluations. The performance of the MTABC algorithm is extensively judged on a set of 20 basic functions and a set of 10 shifted or rotated functions, and is compared favorably with other improved ABCs and several state-of-the-art algorithms. The experimental results show that the proposed algorithm has a higher convergence speed and better search ability for almost all functions.     

An artificial bee colony algorithm for learning Bayesian networks

One basic approach to learn Bayesian networks (BNs) from data is to apply a search procedure to explore the set of candidate networks for the database in light of a scoring metric, where the most popular stochastic methods are based on some meta-heuristic mechanisms, such as Genetic Algorithm, Evolutionary Programming and Ant Colony Optimization. In this paper, we have developed a new algorithm for learning BNs which employs a recently introduced meta-heuristic: artificial bee colony (ABC). All the phases necessary to tackle our learning problem using this meta-heuristic are described, and some experimental results to compare the performance of our ABC-based algorithm with other algorithms are given in the paper.     

自适应人工蜂群算法的盲源分离

盲源分离(BSS)是传感器信号处理领域研究热点,针对传统盲源分离算法大多存在收敛速度慢、分离精度低、适用场合窄的缺点,提出了一种基于自适应人工蜂群算法的盲源分离.利用Givens旋转变换降低计算量,搜索策略引入自适应全局指导项动态调节最优解导向作用,选择策略采用自适应Boltz-mann轮盘赌作改进平衡迭代各阶段选择压力集中程度.实验表明:基于自适应人工蜂群算法的盲源分离,能够加快收敛速度并显著提高分离精度至约3个数量级.     

改进的蜂群算法

针对蜂群算法收敛速度缓慢、容易出现早熟的问题,提出一种改进的蜂群算法(IABC)。IABC在跟随阶段食物源更新中根据邻域个体食物源质量调整信息共享程度,并且随着搜索进程减弱当前食物源的影响、增强邻域信息共享强度,使蜂群在搜索初期快速收敛到最优食物源所在区域、在搜索后期提高全局收敛性能。函数测试结果表明,IABC有效地提高了ABC的收敛速度和优化精度,特别适合复杂函数的优化问题。     

求解车辆路径问题的人工蜂群算法

采用人工蜂群算法对车辆路径问题进行求解,给出食物源的自然数编码方法,并采用邻域倒位方法生成候选食物源。应用算法求解了多个车辆路径问题的实例,并将结果与其它一些启发式算法进行了比较和分析。计算结果表明,人工蜂群算法可以有效求解车辆路径问题,同时也为算法求解其它一些组合优化问题提供了有益思路。     

An efficient and robust artificial bee colony algorithm for numerical optimization

Artificial bee colony (ABC) algorithm has already shown more effective than other population-based algorithms. However, ABC is good at exploration but poor at exploitation, which results in an issue on convergence performance in some cases. To improve the convergence performance of ABC, an efficient and robust artificial bee colony (ERABC) algorithm is proposed. In ERABC, a combinatorial solution search equation is introduced to accelerate the search process. And in order to avoid being trapped in local minima, chaotic search technique is employed on scout bee phase. Meanwhile, to reach a kind of sustainable evolutionary ability, reverse selection based on roulette wheel is applied to keep the population diversity. In addition, to enhance the global convergence, chaotic initialization is used to produce initial population. Finally, experimental results tested on 23 benchmark functions show that ERABC has a very good performance when compared with two ABC-based algorithms.     

A grey artificial bee colony algorithm

Artificial bee colony (ABC) algorithm is a very popular population-based algorithm. Unfortunately, there exists a shortcoming of slow convergence rate, which partly results from random choices of neighbor individuals regarding its solution search equation. A novel scheme for the choice of neighbors is introduced based on grey relational degrees between a current individual and its neighbors to overcome the insufficiency. Then, the chosen neighbor is used to guide the search process. Additionally, inspired by differential evolution, a solution search equation called ABC/rand/2 is employed to balance the previous exploitation and a new perturbation scheme is also employed. What is more, solution search equations using information of the best individual, an opposition-based learning method and a chaotic initialization technique are also integrated into the proposed algorithm called grey artificial bee colony algorithm (GABC for short). Subsequently, the effectiveness and efficiency of GABC are validated on a test suite composed of fifty-seven benchmark functions. Furthermore, it is also compared with a few state-of-the-art algorithms. The related experimental results show the effectiveness and superiority of GABC.     

一种转轴人工蜂群算法

为了提高人工蜂群(ABC)算法的局部搜索能力,加快其收敛速度,将Rosenbrock转轴搜索的方法引入ABC算法,提出了一种转轴ABC算法.该算法每隔一定的迭代次数,就在ABC算法找到的当前极值的邻域内用Rosenbrock方法进行一次转轴搜索,以引导算法找到函数值下降最快的方向.此外,新算法利用对立策略对算法随机产生的初始种群进行调整,得到了质量较高的初始种群.通过对几个标准测试函数的性能测试,验证了算法的快速收敛性和稳定性,说明对其的改进是可行且有效的.     

人工蜂群算法研究综述*

人工蜂群算法自提出以来,受到很多学者的关注,并涌现出大量的研究文献。本文介绍了2013年以来国内外蜂群算法的研究成果,包括加快收敛、提高开采能力、提高算法性能方面的改进;针对约束优化、平行化运行、多目标寻优等多方面的研究;以及人工蜂群算法在神经网络、无线传感网、决策调度、图像信号处理等多个领域的研究现状,并指出人工蜂群算法有待进一步解决的问题及未来的研究方向。     

Elite-guided multi-objective artificial bee colony algorithm

Multi-objective optimization has been a difficult problem and a research focus in the field of science and engineering. This paper presents a novel multi-objective optimization algorithm called elite-guided multi-objective artificial bee colony (EMOABC) algorithm. In our proposal, the fast non-dominated sorting and population selection strategy are applied to measure the quality of the solution and select the better ones. The elite-guided solution generation strategy is designed to exploit the neighborhood of the existing solutions based on the guidance of the elite. Furthermore, a novel fitness calculation method is presented to calculate the selecting probability for onlookers. The proposed algorithm is validated on benchmark functions in terms of four indicators: GD, ER, SPR, and TI. The experimental results show that the proposed approach can find solutions with competitive convergence and diversity within a shorter period of time, compared with the traditional multi-objective algorithms. Consequently, it can be considered as a viable alternative to solve the multi-objective optimization problems.     

A modified artificial bee colony algorithm

Artificial bee colony algorithm (ABC) is a relatively new optimization technique which has been shown to be competitive to other population-based algorithms. However, there is still an insufficiency in ABC regarding its solution search equation, which is good at exploration but poor at exploitation. Inspired by differential evolution (DE), we propose an improved solution search equation, which is based on that the bee searches only around the best solution of the previous iteration to improve the exploitation. Then, in order to make full use of and balance the exploration of the solution search equation of ABC and the exploitation of the proposed solution search equation, we introduce a selective probability P and get the new search mechanism. In addition, to enhance the global convergence, when producing the initial population, both chaotic systems and opposition-based learning methods are employed. The new search mechanism together with the proposed initialization makes up the modified ABC (MABC for short), which excludes the probabilistic selection scheme and scout bee phase. Experiments are conducted on a set of 28 benchmark functions. The results demonstrate good performance of MABC in solving complex numerical optimization problems when compared with two ABC-based algorithms.     

人工蜂群算法的改进

为改善人工蜂群算法(ABC)的深度搜索能力,提出一种改进的人工蜂群算法(SABC)。借鉴混合蛙跳算法(SFLA)的进化机制,将蜂群划分为多个模因组,使每个新个体与自身所在模因组的最坏个体进行优劣比较,能够更加容易保存群体中的"新生"个体,改善群体的整体质量,增加算法的深度搜索能力。通过7个测试函数进行实验,统计结果表明了SABC算法在求解函数优化问题时具有较好的算法性能。     

Gaussian bare-bones artificial bee colony algorithm

As a relatively new global optimization technique, artificial bee colony (ABC) algorithm becomes popular in recent years for its simplicity and effectiveness. However, there is still an inefficiency in ABC regarding its solution search equation, which is good at exploration but poor at exploitation. To overcome this drawback, a Gaussian bare-bones ABC is proposed, where a new search equation is designed based on utilizing the global best solution. Furthermore, we employ the generalized opposition-based learning strategy to generate new food sources for scout bees, which is beneficial to discover more useful information for guiding search. A comprehensive set of experiments is conducted on 23 benchmark functions and a real-world optimization problem to verify the effectiveness of the proposed approach. Some well-known ABC variants and state-of-the-art evolutionary algorithms are used for comparison. The experimental results show that the proposed approach offers higher solution quality and faster convergence speed.     

深层加速搜索的蜂群算法

蜂群(ABC)算法是近年来提出的一种求解优化问题的较新型的仿生进化算法。针对蜂群算法的不足,依据反向搜索的思想,提出一种改进的蜂群算法。在改进算法中,每次邻域搜索之后,通过比较新旧食物源位置的花蜜值(而非适应度)来选择保留较优解。同时,在采蜜蜂采蜜后以一定概率进行反向搜索,保留较优解。邻域搜索的维数也不再限定某一维。基于五个标准测试函数的仿真结果表明,本算法能有效加快收敛速度,提高最优解的精度,其性能明显优于基本的蜂群算法。     

Improved artificial bee colony algorithm for global optimization

The artificial bee colony algorithm is a relatively new optimization technique. This paper presents an improved artificial bee colony (IABC) algorithm for global optimization. Inspired by differential evolution (DE) and introducing a parameter M, we propose two improved solution search equations, namely “ABC/best/1” and “ABC/rand/1”. Then, in order to take advantage of them and avoid the shortages of them, we use a selective probability p to control the frequency of introducing “ABC/rand/1” and “ABC/best/1” and get a new search mechanism. In addition, to enhance the global convergence speed, when producing the initial population, both the chaotic systems and the opposition-based learning method are employed. Experiments are conducted on a suite of unimodal/multimodal benchmark functions. The results demonstrate the good performance of the IABC algorithm in solving complex numerical optimization problems when compared with thirteen recent algorithms.