Image segmentation is vital when analyzing medical images,especially magnetic resonance(MR)images of the brain.Recently,several image segmentation techniques based on multilevel thresholding have been proposed for med...Image segmentation is vital when analyzing medical images,especially magnetic resonance(MR)images of the brain.Recently,several image segmentation techniques based on multilevel thresholding have been proposed for medical image segmentation;however,the algorithms become trapped in local minima and have low convergence speeds,particularly as the number of threshold levels increases.Consequently,in this paper,we develop a new multilevel thresholding image segmentation technique based on the jellyfish search algorithm(JSA)(an optimizer).We modify the JSA to prevent descents into local minima,and we accelerate convergence toward optimal solutions.The improvement is achieved by applying two novel strategies:Rankingbased updating and an adaptive method.Ranking-based updating is used to replace undesirable solutions with other solutions generated by a novel updating scheme that improves the qualities of the removed solutions.We develop a new adaptive strategy to exploit the ability of the JSA to find a best-so-far solution;we allow a small amount of exploration to avoid descents into local minima.The two strategies are integrated with the JSA to produce an improved JSA(IJSA)that optimally thresholds brain MR images.To compare the performances of the IJSA and JSA,seven brain MR images were segmented at threshold levels of 3,4,5,6,7,8,10,15,20,25,and 30.IJSA was compared with several other recent image segmentation algorithms,including the improved and standard marine predator algorithms,the modified salp and standard salp swarm algorithms,the equilibrium optimizer,and the standard JSA in terms of fitness,the Structured Similarity Index Metric(SSIM),the peak signal-to-noise ratio(PSNR),the standard deviation(SD),and the Features Similarity Index Metric(FSIM).The experimental outcomes and the Wilcoxon rank-sum test demonstrate the superiority of the proposed algorithm in terms of the FSIM,the PSNR,the objective values,and the SD;in terms of the SSIM,IJSA was competitive with the others.展开更多
面向园区综合能源系统中供能方与用能方的角色互换,以及园区低碳经济运行的强约束,提出了一种考虑动态参数的阶梯型碳交易机制和需求响应的园区级综合能源系统主从博弈优化调度方法。首先,将园区级综合能源系统中能源运营商(energy syst...面向园区综合能源系统中供能方与用能方的角色互换,以及园区低碳经济运行的强约束,提出了一种考虑动态参数的阶梯型碳交易机制和需求响应的园区级综合能源系统主从博弈优化调度方法。首先,将园区级综合能源系统中能源运营商(energy system operator,ESO)设定为上层领导者、综合能源系统园区设定为下层跟随者,并且能源运营商以最大化自身效益为目标,通过制定与园区间的购售电价格、碳交易基价、价格增长幅度,引导下层园区优化;下层园区以最小化其运行成本为目标,对上层发布的价格信息做出反应,从而构建主从博弈模型。其次,充分考虑园区级综合能源系统的低碳经济运行约束,在博弈模型中引入考虑动态参数的阶梯型碳交易机制以限制二氧化碳排放量,并在园区侧引入需求响应。最后,利用水母搜索算法对上层发布的购售电价、碳交易基价、价格增长幅度进行优化,利用CPLEX优化下层园区设备出力、需求响应以及购售电计划。仿真结果证明了所提模型和方法的有效性。展开更多
提出一种基于改进双种群水母搜索(Improved Double Population Jellyfish Search,IDPJS)算法的多阈值图像分割法,以解决随着阈值数目的增加,传统的图像分割计算量呈指数级增长,分割时间消耗多的问题.首先,初始化两个水母种群P和P,执行...提出一种基于改进双种群水母搜索(Improved Double Population Jellyfish Search,IDPJS)算法的多阈值图像分割法,以解决随着阈值数目的增加,传统的图像分割计算量呈指数级增长,分割时间消耗多的问题.首先,初始化两个水母种群P和P,执行基本的JS算法.在P中引入组合变异策略,两个种群进行交流学习以提高算法的收敛速度.接着,对当前最好解采用动态反向学习策略,防止算法陷入局部最优.其次,利用CEC2017基准函数对所提IDPJS算法进行测试,并与5种启发式算法进行比较,实验结果显示,所提算法精度高、稳定性好.最后,将其用于多阈值图像分割问题,分别在阈值个数为5,7,9的情况下进行测试实验,实验表明,IDPJS算法是解决多阈值图像分割问题的有效方法.展开更多
基金This research was supported by the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(P0012724,The Competency Development Program for Industry Specialist)and the Soonchunhyang University Research Fund.
摘要Image segmentation is vital when analyzing medical images,especially magnetic resonance(MR)images of the brain.Recently,several image segmentation techniques based on multilevel thresholding have been proposed for medical image segmentation;however,the algorithms become trapped in local minima and have low convergence speeds,particularly as the number of threshold levels increases.Consequently,in this paper,we develop a new multilevel thresholding image segmentation technique based on the jellyfish search algorithm(JSA)(an optimizer).We modify the JSA to prevent descents into local minima,and we accelerate convergence toward optimal solutions.The improvement is achieved by applying two novel strategies:Rankingbased updating and an adaptive method.Ranking-based updating is used to replace undesirable solutions with other solutions generated by a novel updating scheme that improves the qualities of the removed solutions.We develop a new adaptive strategy to exploit the ability of the JSA to find a best-so-far solution;we allow a small amount of exploration to avoid descents into local minima.The two strategies are integrated with the JSA to produce an improved JSA(IJSA)that optimally thresholds brain MR images.To compare the performances of the IJSA and JSA,seven brain MR images were segmented at threshold levels of 3,4,5,6,7,8,10,15,20,25,and 30.IJSA was compared with several other recent image segmentation algorithms,including the improved and standard marine predator algorithms,the modified salp and standard salp swarm algorithms,the equilibrium optimizer,and the standard JSA in terms of fitness,the Structured Similarity Index Metric(SSIM),the peak signal-to-noise ratio(PSNR),the standard deviation(SD),and the Features Similarity Index Metric(FSIM).The experimental outcomes and the Wilcoxon rank-sum test demonstrate the superiority of the proposed algorithm in terms of the FSIM,the PSNR,the objective values,and the SD;in terms of the SSIM,IJSA was competitive with the others.
摘要面向园区综合能源系统中供能方与用能方的角色互换,以及园区低碳经济运行的强约束,提出了一种考虑动态参数的阶梯型碳交易机制和需求响应的园区级综合能源系统主从博弈优化调度方法。首先,将园区级综合能源系统中能源运营商(energy system operator,ESO)设定为上层领导者、综合能源系统园区设定为下层跟随者,并且能源运营商以最大化自身效益为目标,通过制定与园区间的购售电价格、碳交易基价、价格增长幅度,引导下层园区优化;下层园区以最小化其运行成本为目标,对上层发布的价格信息做出反应,从而构建主从博弈模型。其次,充分考虑园区级综合能源系统的低碳经济运行约束,在博弈模型中引入考虑动态参数的阶梯型碳交易机制以限制二氧化碳排放量,并在园区侧引入需求响应。最后,利用水母搜索算法对上层发布的购售电价、碳交易基价、价格增长幅度进行优化,利用CPLEX优化下层园区设备出力、需求响应以及购售电计划。仿真结果证明了所提模型和方法的有效性。
摘要提出一种基于改进双种群水母搜索(Improved Double Population Jellyfish Search,IDPJS)算法的多阈值图像分割法,以解决随着阈值数目的增加,传统的图像分割计算量呈指数级增长,分割时间消耗多的问题.首先,初始化两个水母种群P和P,执行基本的JS算法.在P中引入组合变异策略,两个种群进行交流学习以提高算法的收敛速度.接着,对当前最好解采用动态反向学习策略,防止算法陷入局部最优.其次,利用CEC2017基准函数对所提IDPJS算法进行测试,并与5种启发式算法进行比较,实验结果显示,所提算法精度高、稳定性好.最后,将其用于多阈值图像分割问题,分别在阈值个数为5,7,9的情况下进行测试实验,实验表明,IDPJS算法是解决多阈值图像分割问题的有效方法.