A hybrid self-adaptive bees algorithm for examination timetabling problems

A hybrid self-adaptive bees algorithm is proposed for the examination timetabling problems. The bees algorithm (BA) is a population-based algorithm inspired by the way that honey bees forage for food. The algorithm presents a type of neighbourhood search that includes a random search that can be used for optimisation problems. In the BA, the bees search randomly for food sites and return back to the hive carrying the information about the food sites (fitness values); then, other bees will select the sites based on their information (more bees are recruited to the best sites) and will start a random search. We propose three techniques (i.e. disruptive, tournament and rank selection strategies) for selecting the sites, rather than using the fitness value, to improve the diversity of the population. Additionally, a self-adaptive strategy for directing the neighbourhood search is added to further enhance the local intensification capability. Finally, a modified bees algorithm is combined with a local search (i.e. simulated annealing, late acceptance hill climbing) to quickly descend to the optimum solution. Experimental results comparing our proposed modifications with each other and with the basic BA show that all of the modifications outperform the basic BA; an overall comparison has been made with the best known results on two examination timetabling benchmark datasets, which shows that our approach is competitive and works well across all of the problem instances.     

An adaptive artificial bee colony and late-acceptance hill-climbing algorithm for examination timetabling

The artificial bee colony (ABC) is a population-based metaheuristic that mimics the foraging behaviour of honeybees in order to produce high-quality solutions for optimisation problems. The ABC algorithm combines both exploration and exploitation processes. In the exploration process, the worker bees are responsible for selecting a random solution and applying it to a random neighbourhood structure, while the onlooker bees are responsible for choosing a food source based on a selection strategy. In this paper, a disruptive selection strategy is applied within the ABC algorithm in order to improve the diversity of the population and prevent premature convergence in the evolutionary process. A self-adaptive strategy for selecting neighbourhood structures is added to further enhance the local intensification capability (adaptively choosing the neighbourhood structure helps the algorithm to escape local optima). Finally, a modified ABC algorithm is hybridised with a local search algorithm, i.e. the late-acceptance hill-climbing algorithm, to quickly descend to a good-quality solution. The experiments show that the ABC algorithm with the disruptive selection strategy outperforms the original ABC algorithm. The hybridised ABC algorithm also outperforms the lone ABC algorithm when tested on examination timetabling problems.     

基于自适应蜂群优化的DBSCAN聚类算法

针对传统的DBSCAN（Density-Based Spatial Clustering of Application with Noise，DBSCAN）聚类算法全局参数设置不合理、参数选取困难、无法识别重叠模块的问题，以及人工蜂群优化算法（Artificial Bees Colony，ABC）后期收敛速度慢、易陷入局部最优等缺陷进行了研究，提出一种基于自适应人工蜂群优化DBSCAN的聚类算法IABC-DBSCAN。该算法将截断选择机制与锦标赛选择机制相结合，提出一种截断-锦标赛选择机制（Truncation-Championship Selection Mechanism，TCSM），以增强种群多样性、避免跟随蜂选择蜜源陷入局部最优的缺陷；提出一种自适应步长策略（Adaptive Step Strategy，ASS）动态调整跟随蜂的搜索方式，以提高算法局部搜索能力和聚类速度；根据改进的IABC算法动态调节DBSCAN算法中的最优参数，将蜜源位置对应[ε]邻域，蜜源的适应度大小对应DBSCAN的聚类效果，并在多种测试函数和数据集上进行验证。实验结果表明，该算法不仅有效克服ABC和DBSCAN算法的缺陷，且正确率和召回率均有较大提高。     

人工蜂群算法综述

近年来群智能算法发展较为迅速并解决了很多大规模的复杂问题。人工蜂群算法是一种新型的群智能算法, 以其很强的全局收敛性、贪婪启发式的搜索特征以及求解问题的快速性等优越的性能受到广泛关注。简单介绍了人工蜂群算 法提出的生物学背景;由蜜蜂觅食行为与现实问题的求解类比给出了该算法的建模思想;并详细介绍了人工蜂群算法实现的 算法模型;从基于算法的改进以及基于算法的应用两方面讨论了近年来很多学者对人工蜂群算法研究的现状;最后对人工蜂群 算法的研究进行展望,从算法的弱点分析提出了该算法改进的方向以及进一步应用的领域。     

Bee colony optimization for the p-center problem

Bee colony optimization (BCO) is a relatively new meta-heuristic designed to deal with hard combinatorial optimization problems. It is biologically inspired method that explores collective intelligence applied by the honey bees during nectar collecting process. In this paper we apply BCO to the p-center problem in the case of symmetric distance matrix. On the contrary to the constructive variant of the BCO algorithm used in recent literature, we propose variant of BCO based on the improvement concept (BCOi). The BCOi has not been significantly used in the relevant BCO literature so far. In this paper it is proved that BCOi can be a very useful concept for solving difficult combinatorial problems. The numerical experiments performed on well-known benchmark problems show that the BCOi is competitive with other methods and it can generate high-quality solutions within negligible CPU times.     

基于排序选择和精英引导的改进人工蜂群算法

针对人工蜂群算法收敛速度较慢、收敛精度不高的问题,提出一种基于排序选择和精英引导的改进人工蜂群算法.分析观察蜂概率选择方法在适应值变化时对于精英个体优选的不足,提出一种排序选择方法,用以替代概率选择方法,从而提高算法的收敛速度.利用精英个体对搜索的引导作用,分别提出针对采蜜蜂和观察蜂的改进邻域搜索方程,从而提高算法的搜索效率.与其他人工蜂群算法的对比结果表明,所提出的改进方法能够有效提升算法的收敛速度和收敛精度.     

多选择背包问题的人工蜂群算法*

多选择背包问题是组合优化中的NP难题之一,采用一种新的智能优化算法——人工蜂群算法进行求解。该算法通过雇佣蜂、跟随蜂和侦察蜂的局部寻优来实现全局最优。基于算法实现的核心思想,用MATLAB编程实现,对参考文献的算例进行仿真测试。与其他算法进行了比较,获得了满意的结果。这说明了算法在解决该问题上的可行性与有效性,拓展了人工蜂群算法的应用领域。     

An evolutionary image matching approach

Bee colony optimization (BCO) is a meta-heuristic technique inspired by natural behavior of the bee colony. In this paper, the BCO technique is exploited to tackle the shape matching problem with the aim to find the matching between two shapes represented via sets of contour points. A number of bees are used to collaboratively search the optimal matching using a proposed proximity-regularized cost function. Furthermore, the proposed cost function considers the proximity information of the matched contour points; this is in the contrast to that these contour points are treated independently in the conventional approaches. Experimental results are presented to demonstrate that the proposed approach is able to provide more accurate shape matching than the conventional approaches.     

求解多目标不相关并行机调度问题的多群体人工蜂群算法

针对具有预防性维修(PM)和顺序相关准备时间(SDST)的不相关并行机调度问题,提出一种多群体人工蜂群算法(MABC)以同时最小化完工时间和总延迟时间.该算法将雇佣蜂分割成s个雇佣蜂群,除最差雇佣蜂群外,每个雇佣蜂群都对应1个跟随蜂群.结合2个目标函数、PM和SDST的特征设计3种邻域搜索,采用全局搜索和邻域搜索的不同...     

Neighborhood search techniques for solving uncapacitated multilevel lot-sizing problems

In this paper, several neighborhood search techniques for solving uncapacitated multilevel lot-sizing problems are investigated. We introduce three indexes: distance, changing range, and changing level that have great influence on the searching efficacy of neighborhood search techniques. These insights can help develop more efficient heuristic algorithms. As a result, we have developed an iterated neighborhood search (INS) algorithm that is very simple but that demonstrates good performance when tested against 176 benchmark instances under different scales (small, medium, and large), with 25 instances having been updated with new best known solutions in the computing experiments.     

A dynamic multi-colony artificial bee colony algorithm for multi-objective optimization

This paper suggests a dynamic multi-colony multi-objective artificial bee colony algorithm (DMCMOABC) by using the multi-deme model and a dynamic information exchange strategy. In the proposed algorithm, K colonies search independently most of the time and share information occasionally. In each colony, there are S bees containing equal number of employed bees and onlooker bees. For each food source, the employed or onlooker bee will explore a temporary position generated by using neighboring information, and the better one determined by a greedy selection strategy is kept for the next iterations. The external archive is employed to store non-dominated solutions found during the search process, and the diversity over the archived individuals is maintained by using crowding-distance strategy. If a randomly generated number is smaller than the migration rate R, then an elite, defined as the intermediate individual with the maximum crowding-distance value, is identified and used to replace the worst food source in a randomly selected colony. The proposed DMCMOABC is evaluated on a set of unconstrained/constrained test functions taken from the CEC2009 special session and competition in terms of four commonly used metrics EPSILON, HV, IGD and SPREAD, and it is compared with other state-of-the-art algorithms by applying Friedman test on the mean of IGD. The test results show that DMCMOABC is significantly better than or at least comparable to its competitors for both unconstrained and constrained problems.     

基于改进混合蜂群算法的非线性电路谐波平衡分析

针对射频电路非线性分析中谐波平衡方程求解问题,提出一种基于高斯扰动、锦标赛选择策略以及拟牛顿局部寻优算子的改进混合蜂群算法,该算法在搜索方程中引入基于当前全局最优解的高斯扰动,能有效防止算法陷入局部最优并加快算法收敛;跟随蜂采用锦标赛选择策略在一定程度上避免了算法的早熟现象;采用拟牛顿算子进行局部寻优,可使算法快速收敛。实验结果表明,改进混合蜂群算法成功应用于谐波平衡方程求解,与其他求解算法对比,收敛时间较短,性能较优。     

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。     

The continuous artificial bee colony algorithm for binary optimization

Artificial bee colony (ABC) algorithm, one of the swarm intelligence algorithms, has been proposed for continuous optimization, inspired intelligent behaviors of real honey bee colony. For the optimization problems having binary structured solution space, the basic ABC algorithm should be modified because its basic version is proposed for solving continuous optimization problems. In this study, an adapted version of ABC, ABC_bin for short, is proposed for binary optimization. In the proposed model for solving binary optimization problems, despite the fact that artificial agents in the algorithm works on the continuous solution space, the food source position obtained by the artificial agents is converted to binary values, before the objective function specific for the problem is evaluated. The accuracy and performance of the proposed approach have been examined on well-known 15 benchmark instances of uncapacitated facility location problem, and the results obtained by ABC_bin are compared with the results of continuous particle swarm optimization (CPSO), binary particle swarm optimization (BPSO), improved binary particle swarm optimization (IBPSO), binary artificial bee colony algorithm (binABC) and discrete artificial bee colony algorithm (DisABC). The performance of ABC_bin is also analyzed under the change of control parameter values. The experimental results and comparisons show that proposed ABC_bin is an alternative and simple binary optimization tool in terms of solution quality and robustness.     

An improved artificial bee colony algorithm based on the strategy of global reconnaissance

The artificial bee colony (ABC) algorithm is a recently introduced swarm intelligence optimization algorithm based on the foraging behavior of a honeybee colony. However, many problems are encountered in the ABC algorithm, such as premature convergence and low solution precision. Moreover, it can easily become stuck at local optima. The scout bees start to search for food sources randomly and then they share nectar information with other bees. Thus, this paper proposes a global reconnaissance foraging swarm optimization algorithm that mimics the intelligent foraging behavior of scouts in nature. First, under the new scouting search strategies, the scouts conduct global reconnaissance around the assigned subspace, which is effective to avoid premature convergence and local optima. Second, the scouts guide other bees to search in the neighborhood by applying heuristic information about global reconnaissance. The cooperation between the honeybees will contribute to the improvement of optimization performance and solution precision. Finally, the prediction and selection mechanism is adopted to further modify the search strategies of the employed bees and onlookers. Therefore, the search performance in the neighborhood of the local optimal solution is enhanced. The experimental results conducted on 52 typical test functions show that the proposed algorithm is more effective in avoiding premature convergence and improving solution precision compared with some other ABCs and several state-of-the-art algorithms. Moreover, this algorithm is suitable for optimizing high-dimensional space optimization problems, with very satisfactory outcomes.     

DisABC: A new artificial bee colony algorithm for binary optimization

Artificial bee colony (ABC) algorithm is one of the recently proposed swarm intelligence based algorithms for continuous optimization. Therefore it is not possible to use the original ABC algorithm directly to optimize binary structured problems. In this paper we introduce a new version of ABC, called DisABC, which is particularly designed for binary optimization. DisABC uses a new differential expression, which employs a measure of dissimilarity between binary vectors in place of the vector subtraction operator typically used in the original ABC algorithm. Such an expression helps to maintain the major characteristics of the original one and is respondent to the structure of binary optimization problems, too. Similar to original ABC algorithm, DisABC's differential expression works in continuous space while its consequence is used in a two-phase heuristic to construct a complete solution in binary space. Effectiveness of DisABC algorithm is tested on solving the uncapacitated facility location problem (UFLP). A set of 15 benchmark test problem instances of UFLP are adopted from OR-Library and solved by the proposed algorithm. Results are compared with two other state of the art binary optimization algorithms, i.e., binDE and PSO algorithms, in terms of three quality indices. Comparisons indicate that DisABC performs very well and can be regarded as a promising method for solving wide class of binary optimization problems.     

基于变异精密搜索的蜂群聚类算法

针对K-means 聚类算法过度依赖初始聚类中心、局部收敛、稳定性差等问题, 提出一种基于变异精密搜索的蜂群聚类算法. 该算法利用密度和距离初始化蜂群, 并根据引领蜂的适应度和密度求解跟随蜂的选择概率P;  然后通过变异精密搜索法产生的新解来更新侦查蜂, 以避免陷入局部最优; 最后结合蜂群与粗糙集来优化K-means. 实验结果表明, 该算法不仅能有效抑制局部收敛、减少对初始聚类中心的依赖, 而且准确率和稳定性均有较大的提高.

     

A swarm intelligence approach to the quadratic minimum spanning tree problem

The quadratic minimum spanning tree problem (Q-MST) is an extension of the minimum spanning tree problem (MST). In Q-MST, in addition to edge costs, costs are also associated with ordered pairs of distinct edges and one has to find a spanning tree that minimizes the sumtotal of the costs of individual edges present in the spanning tree and the costs of the ordered pairs containing only edges present in the spanning tree. Though MST can be solved in polynomial time, Q-MST is NP-Hard. In this paper we present an artificial bee colony (ABC) algorithm to solve Q-MST. The ABC algorithm is a new swarm intelligence approach inspired by intelligent foraging behavior of honey bees. Computational results show the effectiveness of our approach.     

具有自适应全局最优引导快速搜索策略的人工蜂群算法

针对人工蜂群算法存在开发与探索能力不平衡的缺点,提出了具有自适应全局最优引导快速搜索策略的改进算法.在该策略中,首先采蜜蜂利用自适应搜索方程平衡了不同搜索方法的探索和开发能力;其次跟随蜂利用全局最优引导邻域搜索方程对蜜源进行精细化搜索,以提高其收敛精度和全局搜索能力.14个标准测试函数的仿真结果表明,相比其他算法,所提出的改进算法有效平衡了算法的开发与探索能力,并提高了其最优解的精度及收敛速度.     

A variable neighborhood search based approach for uncapacitated multilevel lot-sizing problems

In this paper, an effective approach based on the variable neighborhood search (VNS) algorithm is presented to solve the uncapacitated multilevel lot-sizing (MLLS) problems with component commonality and multiple end-items. A neighborhood structure for the MLLS problem is defined, and two kinds of solution move policies, i.e., move at first improvement (MAFI) and move at best improvement (MABI), are used in the algorithm. A new rule called Setup shifting is developed to conduct a more efficient neighborhood search for the MLLS problems. Computational studies are carried out on two sets of benchmark problems. The experimental results show that the VNS algorithm is capable of solving MLLS problems with good optimality and high computational efficiency as well, outperforming most of the existing algorithms in comparison.