-
摘要: 针对最小化最大完工时间的柔性流水车间调度,利用事件建模思想,线性化0-1混合整数规划模型,使得小规模调度问题通过Cplex可以准确求解,同时设计了高效分布估算算法来求解大规模调度问题.该算法采用的是一种新颖的随机规则解码方式,工件排序按选定的规则安排而机器按概率随机分配.针对分布估算算法中的概率模型不能随种群中个体各位置上工件的更新而自动调整的缺点,提出了自适应调整概率模型,该概率模型能提高分布估算算法的收敛质量和速度.同时为提高算法局部搜索能力和防止算法陷入局部最优,设计了局部搜索和重启机制.最后,采用实验设计方法校验了高效分布估算算法参数的最佳组合.算例和实例测试结果都表明本文提出的高效分布估算算法在求解质量和稳定性上均优于遗传算法、引力搜索算法和经典分布估算算法.Abstract: For flexible flow shop scheduling which minimizes the maximum completion time, a 0-1 mixed integer linear programming model is established by using event modeling method, and small-scale scheduling problems can be accurately solved through any linear solver. At the same time, an efficient estimation of distribution algorithm is designed to solve large-scale problems. A novel decoding way with random probability and rules is adopted by the new algorithm, and workpiece sequencing is based on rule while assignment of machines is based on random probability. Since the original probability model does not automatically adjust sampling probability, an improved probability model is put forward. And local search and restart mechanism are designed and adopted to improve the ability of local search and to avoid falling into local optimum. Finally, optimal combination of parameters is decided by using experimental design method, and experimental results show that the new algorithm outperforms genetic algorithm, gravitational search algorithm, and classical estimation of distribution algorithm in terms of quality and stability.1) 本文责任编委 宋士吉
-
表 1 解码方法的伪代码和复杂度
Table 1 Pseudo-code and complexity for decoding method
Algorithm 1. Template of decoding O (max{Snlog (n), nMlog (m)}) Input: π as the coding, and πt as the t-th processed job number, P_m as the probability, O (C) j=1 (j is the index of the stages); O (1) Repeat O (max{Snlog (n), nM log (m)}) t=1; O (1) Repeat O (nmjlog (mj)) Randomly generating a number of [0, 1] which is noted as P m; O (1) Calculating the completion time of πt processed on each machine (Tπt, j, k) according to equation (12); O (mj) If P_m≤P_m, the machine of the minimum Tπt, j, k is chosen and is noted as k*; O (mjlog (mj)) Else, a machine is randomly chosen and is noted as k*; O (mjlog (mj)) Setting Eπt, j=Tπt, j, k, Bπt, j=Tπt, j, k* -Pπt, k*; O (1) t + + O (1) Until t=n O (1) Reorganizing the sequence of jobs according to the ascending order of Eπt, j; O (nlog (n)) Updating π as the sequence of jobs; O (n) j + + O (1) Until j=S O (1) Output: Final solution found. O (C) 表 2 概率矩阵构建与种群更新的伪代码和复杂度
Table 2 Pseudo-code and complexity for constructing probability matrix and updating population
Algorithm 2. Template of construction probability matrix and updating population O (GPsize(n2 -n)/2) Input: Sp as dominant population. Pt.i(g) as the probability matrix; 0(n2) g as the index evolutional generation, g=0; 0(1) Repeat O (GPsize(n2 -n)/2) Determining the values of ISt, il (g) according to Sp; O (n2|Sp|) Calculating Pt, i(g + 1) by equation (13) and setting Pt, i0 (g + 1)=Pt, i(g + 1); 0(n2) l=l; 0(1) Setting I as the sequence of jobs in the individual l; O (n) Repeat O (Psize(n2 -n)/2) t=1; 0(1) Updating the job of individual l which is arranged at position t according to Pt, i0 (g + 1) by the roulette approach; 0(n -1) Noting the job as i* 0(1) Repeat O ((n2-n)/2) I'={i, i ∈ I/i*} O (n -t) Calculating Pt, i0 (g + 1) by equation (14). O (n -t) Dynamically updating Pt', i(g + 1), as Pt', i'(g + 1), O (n -t) t + + O (1) I=[]; I=I'; O (n -t) Updating the job of individual l which is arranged at position t according to (3 + 1) by the roulette approach; O (n -1) Until t==n O (1) l + + O (1) Until l==Psize O (1) Calculating the target values for all of updated individuals by decoding method; O (Psizesnlog (n)) Sequencing the individuals in ascending order of target values; O (Psixesnlog (n)) Selecting the top η % of individuals as sp; O (|sp|) g + + O (1) Until the termination criteria are achieved O (1) Output: Final solution found. O (C) 表 3 改进概率模型的性能
Table 3 The performance of improved probability model
代数 EDA_I EDA_W 最优值 多样性 时间(s) 最优值 多样性 时间(s) 10代 249.0 0.83 0.93 251.0 0.89 0.97 50代 237.1 0.35 4.78 241.2 0.60 4.80 100代 230.0 0.09 9.71 239.8 0.23 10.02 200代 226.7 0.01 19.38 235.5 0.03 20.72 500代 223.4 0.00 48.31 230.9 0.00 52.60 表 4 重启操作的正交实验结果
Table 4 Results for orthogonal test of restart operation
参数组合 水平 AVG $Div{\_}h$ G_max Res 1 2 2 1 222.30 2 2 1 2 223.75 3 4 1 1 223.90 4 3 2 1 222.40 5 3 1 3 219.60 6 1 3 1 223.90 7 1 1 1 223.55 8 1 1 2 223.10 9 3 1 1 221.25 10 1 2 3 222.25 11 4 2 2 222.55 12 4 1 3 219.65 13 2 1 1 223.00 14 3 3 2 222.40 15 4 3 1 224.40 16 2 3 3 219.95 表 5 重启操作的极差表
Table 5 Rang table of restart operation
水平 $Div{\_}\, h$ G_max Res 1 223.200 222.263 223.088 2 222.150 222.375 222.950 3 221.487 222.563 220.338 4 222.625 - - 极差 1.713 0.300 2.750 等级 2 3 1 表 6 重启操作中三种影响因素的方差分析
Table 6 ANOVA for three factors of restart operation
Source Type Ⅲ sum of squares df Mean square F Sig. Partial eta squared Corrected model 28.553a 7 4.079 4.510 0.025 0.798 Intercept 646 099.042 1 646 099.042 714 322.413 0.000 1.000 $Div{\_}h$ 6.324 3 2.108 2.331 0.151 0.466 G_max 0.240 2 0.120 0.133 0.877 0.032 Res 21.988 2 10.994 12.155 0.004 0.752 表 7 高效EDA算法各操作复杂度
Table 7 The complexity of efficient EDA
操作名称 复杂度 初始化 O$(nP_{size})$ 评价种群 O$(P_{size} Mn\log (n))$ 选择优势种群并计算概率 O$(n^2SP_{size})$ 按概率生产新种群 O$(n^2P_{size})$ 邻域搜索 O$Mn^{3})$或O$Mn^{2})$ 重启操作 O$(P_{size}${$Mn$log($n))$ 表 8 算法参数正交实验结果
Table 8 Results for orthogonal test of algorithm parameters
参数组合 水平 AVG $Div{\_}h$ G_max Res 1 2 2 4 193.40 2 2 1 2 193.94 3 4 1 4 192.66 4 3 2 1 197.29 5 3 1 3 192.51 6 1 3 4 195.14 7 1 1 1 195.54 8 1 4 2 197.54 9 3 4 4 195.40 10 1 2 3 194.26 11 4 2 2 195.29 12 4 4 3 195.97 13 2 4 1 198.71 14 3 3 2 196.29 15 4 3 1 197.14 16 2 3 3 194.46 表 9 高效EDA各参数的极差
Table 9 Rang for the parameters of efficient EDA
水平 $Div{\_}\, h$ G_max Res 1 195.620 193.663 197.170 2 195.128 195.060 195.765 3 195.373 195.758 194.300 4 195.265 196.905 194.150 极差 0.492 3.242 3.020 等级 3 1 2 表 10 高效EDA的三种参数的方差分析
Table 10 ANOVA for three parameters of efficient EDA
Source Type Ⅲ sum of squares df Mean square F Sig. Partial eta squared Corrected model 46.692a 9 5.188 39.490 0.000 0.983 Intercept 610 562.518 1 610 562.518 4 647 478.731 0.000 1.000 $P_{size}$ 0.520 3 0.173 1.320 0.352 0.398 $\eta $ 22.063 3 7.354 55.980 0.000 0.966 a 24.108 3 8.036 61.169 0.000 0.968 表 11 四种算法的均值及标准差
Table 11 The mean and standard deviation of these four algorithms
解码方法 Mean Std. deviation N GA 规则 200.8500 13.46325 40 随机规则 197.2000 13.49112 40 Total 199.0250 13.51696 80 GSA 规则 198.5750 13.51331 40 随机规则 189.7000 12.44928 40 Total 194.1375 13.66020 80 EDA 规则 199.43 13.454 40 随机规则 193.20 12.113 40 Total 196.31 13.100 80 EDA_H 规则 188.68 13.234 40 随机规则 184.42 13.042 40 Total 186.55 13.229 80 表 12 组间因素测试结果
Table 12 Test results of between-subjects
Source Square sum df Mean square F Sig. Partial eta squared Intercept 12 044 296.013 1 12 044 296.013 19 397.610 0.000 0.996 Decode 2 645.000 1 2 645.000 4.260 0.042 0.052 Error 48 431.488 78 620.917 - - - 表 13 多元变量测试结果
Table 13 Test results of multivariate
Effect Value F Hypoth-esis df Error df Sig. Partial eta squared 算法 Pillai's trace 0.882 190.021a 3.000 76.000 0.000 0.882 Wilks' lambda 0.118 190.021a 3.000 76.000 0.000 0.882 Hotelling's trace 7.501 190.021a 3.000 76.000 0.000 0.882 Roy's largest root 7.501 190.021a 3.000 76.000 0.000 0.882 算法加解码 Pillai's trace 0.314 11.617a 3.000 76.000 0.000 0.314 Wilks' lambda 0.686 11.617a 3.000 76.000 0.000 0.314 Hotelling's trace 0.459 11.617a 3.000 76.000 0.000 0.314 Roy's largest root 0.459 11.617a 3.000 76.000 0.000 0.314 表 14 三个实例在四种算法及原文献中的结果对比
Table 14 Comparison for the results of three cases under these four algorithms and original documents
次数 文献结果 GA GSA EDA_W EDA_I L1 L2 L3 L1 L2 L3 L1 L2 L3 L1 L2 L3 L1 L2 L3 1 23 297 14 22 298 13.5 22 297 13.5 23 298 13.5 21 297 13 2 24 297 14 22 297 13.5 22 297 13.5 22 297 14 22 297 13 3 23 297 15 22 298 13.5 22 297 13.5 21 300 13.5 21 297 13 4 23 297 14 22 298 13.5 21 298 13.5 22 298 13.5 21 297 13.5 5 23 298 14 22 297 13.5 22 297 13.5 22 297 14 21 297 13 6 23 297 14.5 22 300 13.5 22 298 13.5 21 297 13.5 21 297 13 7 24 297 14 22 298 13.5 21 298 13.5 23 300 14 21 298 13 8 24 298 14.5 22 298 13.5 22 297 13.5 22 197 13.5 21 297 13.5 9 23 298 14 22 298 13.5 22 298 13.5 23 298 13.5 21 297 13 10 24 298 14 22 299 13.5 22 298 13.5 22 298 14 21 297 13 -
[1] Salvador M S. A solution to a special class of flow shop scheduling problems. In:Proceedings of the 1973 Symposium on the Theory of Scheduling and Its Applications. Berlin, Germany:Springer, 1973. 83-92 [2] 李铁克, 苏志雄.炼钢连铸生产调度问题的两阶段遗传算法.中国管理科学, 2009, 17(4):68-74 http://www.cnki.com.cn/Article/CJFDTOTAL-ZGGK200905010.htmLi Tie-Ke, Su Zhi-Xiong. Two-stage genetic algorithm for SM-CC production scheduling. Chinese Journal of Management Science, 2009, 17(4):68-74 http://www.cnki.com.cn/Article/CJFDTOTAL-ZGGK200905010.htm [3] 王圣尧, 王凌, 许烨.求解相同并行机混合流水线车间调度问题的分布估算算法.计算机集成制造系统, 2013, 19(6):1304-1312 http://www.cnki.com.cn/Article/CJFDTOTAL-JSJJ201306018.htmWang Sheng-Yao, Wang Ling, Xu Ye. Estimation of distribution algorithm for solving hybrid flow-shop scheduling problem with identical parallel machine. Computer Integrated Manufacturing Systems, 2013, 19(6):1304-1312 http://www.cnki.com.cn/Article/CJFDTOTAL-JSJJ201306018.htm [4] 王凌, 周刚, 许烨, 金以慧.混合流水线调度研究进展.化工自动化及仪表, 2011, 38(1):1-8, 22 http://www.cnki.com.cn/Article/CJFDTOTAL-HGZD201101002.htmWang Ling, Zhou Gang, Xu Ye, Jin Yi-Hui. Advances in the study on hybrid flow-shop scheduling. Control and Instruments in Chemical Industry, 2011, 38(1):1-8, 22 http://www.cnki.com.cn/Article/CJFDTOTAL-HGZD201101002.htm [5] 王凌, 周刚, 许烨, 王圣尧.求解不相关并行机混合流水线调度问题的人工蜂群算法.控制理论与应用, 2012, 29(12):1551-1557 http://www.cnki.com.cn/Article/CJFDTOTAL-KZLY201212004.htmWang Ling, Zhou Gang, Xu Ye, Wang Sheng-Yao. An artificial bee colony algorithm for solving hybrid flow-shop scheduling problem with unrelated parallel machines. Control Theory & Applications, 2012, 29(12):1551-1557 http://www.cnki.com.cn/Article/CJFDTOTAL-KZLY201212004.htm [6] Graham R L, Lawler E L, Lenstra J K, Kan A H G R. Optimization and approximation in deterministic sequencing and scheduling:a survey. Annals of Discrete Mathematics, 1979, 5:287-326 doi: 10.1016/S0167-5060(08)70356-X [7] Linn R, Zhang W. Hybrid flow shop scheduling:a survey. Computer & Industrial Engineering, 1999, 37(1-2):57-61 http://www.ingentaconnect.com/content/els/03608352/1999/00000037/00000001/art00023 [8] Kis L, Pesch E. A review of exact solution methods for the non-preemptive multiprocessor flowshop problem. European Journal of Operational Research, 2005, 164(3):592-608 doi: 10.1016/j.ejor.2003.12.026 [9] Azizoğlu M, Çakmak E, Kondakci S. A flexible flowshop problem with total flow time minimization. European Journal of Operational Research, 2001, 132(3):528-538 doi: 10.1016/S0377-2217(00)00142-9 [10] Nawaz M, Enscore E E Jr, Ham I. A heuristic algorithm for the m-machine, n-job flow-shop sequencing problem. Omega, 1983, 11(1):91-95 doi: 10.1016/0305-0483(83)90088-9 [11] Palmer D S. Sequencing jobs through a multi-stage process in the minimum total time-a quick method of obtaining a near optimum. Journal of the Operational Research Society, 1965, 16(1):101-107 doi: 10.1057/jors.1965.8 [12] Campbell H G, Dudek R A, Smith M L. A heuristic algorithm for the n job, m machine sequencing problem. Management Science, 1970, 16(10):B630-B637 doi: 10.1287/mnsc.16.10.B630 [13] Ruiz R, Vázquez-Rodríguez J A. The hybrid flow shop scheduling problem. European Journal of Operational Research, 2010, 205(1):1-18 doi: 10.1016/j.ejor.2009.09.024 [14] Shiau D F, Huang Y M. A hybrid two-phase encoding particle swarm optimization for total weighted completion time minimization in proportionate flexible flow shop scheduling. The International Journal of Advanced Manufacturing Technology, 2012, 58(1):339-357 doi: 10.1007/s00170-011-3378-3 [15] Tran T H, Ng K M. A water-flow algorithm for flexible flow shop scheduling with intermediate buffers. Journal of Scheduling, 2011, 14(5):483-500 doi: 10.1007/s10951-010-0205-x [16] 宋代立, 张洁.蚁群算法求解混合流水车间分批调度问题.计算机集成制造系统, 2013, 19(7):1640-1647 http://www.cnki.com.cn/Article/CJFDTOTAL-JSJJ201307024.htmSong Dai-Li, Zhang Jie. Batch scheduling problem of hybrid flow shop based on ant colony algorithm. Computer Integrated Manufacturing Systems, 2013, 19(7):1640-1647 http://www.cnki.com.cn/Article/CJFDTOTAL-JSJJ201307024.htm [17] 王圣尧, 王凌, 许烨, 周刚.求解混合流水车间调度问题的分布估计算法.自动化学报, 2012, 38(3):437-443 doi: 10.3724/SP.J.1004.2012.00437Wang Sheng-Yao, Wang Ling, Xu Ye, Zhou Gang. An estimation of distribution algorithm for solving hybrid flow-shop scheduling problem. Acta Automatica Sinica, 2012, 38(3):437-443 doi: 10.3724/SP.J.1004.2012.00437 [18] Guinet A G P, Solomon M M. Scheduling hybrid flowshops to minimize maximum tardiness or maximum completion time. International Journal of Production Research, 1996, 34(6):1643-1654 doi: 10.1080/00207549608904988 [19] Engin O, Döyen A. A new approach to solve hybrid flow shop scheduling problems by artificial immune system. Future Generation Computer Systems, 2004, 20(6):1083-1095 doi: 10.1016/j.future.2004.03.014 [20] Kahraman C, Engin O, Kaya I, Yilmaz M K. An application of effective genetic algorithms for solving hybrid flow shop scheduling problems. International Journal of Computational Intelligence Systems, 2008, 1(2):134-147 doi: 10.1080/18756891.2008.9727611 [21] Niu Q, Zhou T J, Ma S W. A quantum-inspired immune algorithm for hybrid flow shop with makespan criterion. Journal of Universa1 Computer Science, 2009, 15(4):765-785 https://www.researchgate.net/publication/220349710_A_Quantum-Inspired_Immune_Algorithm_for_Hybrid_Flow_Shop_with_Makespan_Criterion [22] Baluja S. Population-based incremental learning:a method for integrating genetic search based function optimization and competitive learning, Technical Report CMU-CS-94-163, Computer Science Department, Carnegie Mellon University, USA, 1994. [23] Mühlenbein H, Paaß G. From recombination of genes to the estimation of distributions Ⅰ. binary parameters. In:Proceedings of the 4th International Conference on Parallel Problem Solving from Nature. Berlin, Germany:Springer, 1996. 178-187 [24] Larrańaga P, Lozano J A. Estimation of Distribution Algorithms:A New Tool for Evolutionary Computation. Boston, USA:Kluwer Press, 2002. 57-61 [25] 周树德, 孙增圻.分布估计算法综述.自动化学报, 2007, 33(2):113-124 doi: 10.1360/aas-007-0113Zhou Shu-De, Sun Zeng-Qi. A survey on estimation of distribution algorithms. Acta Automatica Sinica, 2007, 33(2):113-124 doi: 10.1360/aas-007-0113 [26] 王圣尧, 王凌, 方晨, 许烨.分布估计算法研究进展.控制与决策, 2012, 27(7):961-966, 974 http://www.cnki.com.cn/Article/CJFDTOTAL-KZYC201207002.htmWang Sheng-Yao, Wang Ling, Fang Chen, Xu Ye. Advances in estimation of distribution algorithms. Control and Decision, 2012, 27(7):961-966, 974 http://www.cnki.com.cn/Article/CJFDTOTAL-KZYC201207002.htm [27] Rabiee M, Rad R S, Mazinani M, Shafaei R. An intelligent hybrid meta-heuristic for solving a case of no-wait two-stage flexible flow shop scheduling problem with unrelated parallel machines. The International Journal of Advanced Manufacturing Technology, 2014, 71(5):1229-1245 https://www.researchgate.net/publication/262686363_An_intelligent_hybrid_meta-heuristic_for_solving_a_case_of_no-wait_two-stage_flexible_flow_shop_scheduling_problem_with_unrelated_parallel_machines?_sg=hC1vVOP0bkPT-eYhm4xL-WBqnnvcOKuG0_yYX3VDOVqmnKCf1gfvUNCxgms3TSRH93CGqFpMCG-oSMaXMYEdmw [28] 张凤超.改进的分布估计算法求解混合流水车间调度问题研究.软件导刊, 2014, 13(8):23-36 http://www.cnki.com.cn/Article/CJFDTOTAL-RJDK201408010.htmZhang Feng-Chao. An improved estimation of distribution algorithm to solve the hybrid flow shop scheduling problem. Software Guide, 2014, 13(8):23-36 http://www.cnki.com.cn/Article/CJFDTOTAL-RJDK201408010.htm [29] Shaik M A, Floudas C A. Unit-specific event-based continuous-time approach for short-term scheduling of batch plants using RTN framework. Computers & Chemical Engineering, 2008, 32(1-2):260-274 https://www.researchgate.net/publication/223556750_Unit-specific_event-based_continuous-time_approach_for_short-term_scheduling_of_batch_plants_using_RTN_framework [30] Li J, Floudas C A. Optimal event point determination for short-term scheduling of multipurpose batch plants via unit-specific event-based continuous-time approaches. Industrial & Engineering Chemistry Research, 2010, 49(16):7446-7469 https://www.researchgate.net/publication/231391276_Optimal_Event_Point_Determination_for_Short-Term_Scheduling_of_Multipurpose_Batch_Plants_via_Unit-Specific_Event-Based_Continuous-Time_Approaches [31] Li J, Xiao X, Tang Q H, Floudas C A. Production scheduling of a large-scale steelmaking continuous casting process via unit-specific event-based continuous-time models:short-term and medium-term scheduling. Industrial & Engineering Chemistry Research, 2012, 51(21):7300-7319 https://www.researchgate.net/publication/263954240_Production_Scheduling_of_a_Large-Scale_Steelmaking_Continuous_Casting_Process_via_Unit-Specific_Event-Based_Continuous-Time_Models_Short-Term_and_Medium-Term_Scheduling [32] 陈荣秋.生产计划与控制:概念、方法与系统.武汉:华中理工大学出版社, 1995. 48Chen Rong-Qiu. Production Planning and Control:Concept, Method and System. Wuhan:Huazhong University of Technology Press, 1995. 48 [33] Shaffer C A[著], 张铭, 刘晓丹等[译].数据结构与算法分析(C++版) (第3版).北京:电子工业出版社, 2013. 31Shaffer C A[Author], Zhang Ming, Liu Xiao-Dan, et al[Translator]. Data structure and Algorithm Analysis in C++(Third edition). Beijing:Publishing House of Electronics Industry, 2013. 31 [34] Pan Q K, Ruiz R. An estimation of distribution algorithm for lot-streaming flow shop problems with setup times. Omega, 2012, 40(2):166-180 doi: 10.1016/j.omega.2011.05.002 [35] 屈国强.瓶颈指向的启发式算法求解混合流水车间调度问题.信息与控制, 2012, 41(4):514-521, 528 http://www.cnki.com.cn/Article/CJFDTOTAL-XXYK201204019.htmQu Guo-Qiang. Bottleneck focused heuristic algorithm for hybrid flow shop scheduling problem. Information and Control, 2012, 41(4):514-521, 528 http://www.cnki.com.cn/Article/CJFDTOTAL-XXYK201204019.htm [36] 潘全科, 高亮, 李新宇.流水车间调度及其优化算法.武汉:华中科技大学出版社, 2013. 97-101Pan Quan-Ke, Gao Liang, Li Xin-Yu. Flow Shop Scheduling and Optimization Algorithms. Wuhan:Huazhong University of Technology Press, 2013. 97-101 [37] Pan Q K, Ruiz R. An effective iterated greedy algorithm for the mixed no-idle permutation flowshop scheduling problem. Omega, 2014, 44:41-50 doi: 10.1016/j.omega.2013.10.002 [38] Vallada E, Ruiz R. Genetic algorithms with path relinking for the minimum tardiness permutation flowshop problem. Omega, 2010, 38(1-2):57-67 doi: 10.1016/j.omega.2009.04.002 [39] Wineberg M, Oppacher F. The underlying similarity of diversity measures used in evolutionary computation. Genetic and Evolutionary Computation. Berlin, Heidelberg:Springer, 2003. 1493-1504 [40] Ruiz R, Maroto C, Alcaraz J. Two new robust genetic algorithms for the flowshop scheduling problem. Omega, 2006, 34(5):461-476 doi: 10.1016/j.omega.2004.12.006 [41] 王凌.车间调度及其遗传算法.北京:清华大学出版社, 2003. 127Wang Ling. Shop Scheduling with Genetic Algorithms. Beijing:Tsinghua University Press, 2003. 127 [42] Ruiz R, Maroto C. A genetic algorithm for hybrid flowshops with sequence dependent setup times and machine eligibility. European Journal of Operational Research, 2006, 169(3):781-800 doi: 10.1016/j.ejor.2004.06.038 [43] Han X H, Chang X M. A chaotic digital secure communication based on a modified gravitational search algorithm filter. Information Sciences, 2012, 208:14-27 doi: 10.1016/j.ins.2012.04.039 [44] Bahrololoum A, Nezamabadi-Pour H, Bahrololoum H, Saeed M. A prototype classifier based on gravitational search algorithm. Applied Soft Computing, 2012, 12(2):819-825 doi: 10.1016/j.asoc.2011.10.008 [45] 谷文祥, 李向涛, 朱磊, 周俊萍, 胡艳梅.求解流水线调度问题的万有引力搜索算法.智能系统学报, 2010, 5(5):411-418 http://www.cnki.com.cn/Article/CJFDTOTAL-ZNXT201005005.htmGu Wen-Xiang, Li Xiang-Tao, Zhu Lei, Zhou Jun-Ping, Hu Yan-Mei. A gravitational search algorithm for flow shop scheduling. CAAI Transactions on Intelligent Systems, 2010, 5(5):411-418 http://www.cnki.com.cn/Article/CJFDTOTAL-ZNXT201005005.htm