Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathem...Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathematical formulation.However,poor performance of existing level set models on noisy images and weak boundary limit its application in image segmentation.In this paper,we present a region consistency constraint term to measure the regional consistency on both sides of the boundary,this term defines the boundary of the image within a range,and hence increases the stability of the level set model.The term can make existing level set models significantly improve the efficiency of the algorithms on segmenting images with noise and weak boundary.Furthermore,this constraint term can make edge-based level set model overcome the defect of sensitivity to the initial contour.The experimental results show that our algorithm is efficient for image segmentation and outperform the existing state-of-art methods regarding images with noise and weak boundary.展开更多
This paper presents an improved method for H-two control with regional stability constraints for the closedloop system. The controller is given by the convex combination of a set of fixed gains. Both continuous and di...This paper presents an improved method for H-two control with regional stability constraints for the closedloop system. The controller is given by the convex combination of a set of fixed gains. Both continuous and discrete-time systems in a known polytopic domain are investigated. New LMI-based sufficient conditions for the existence of parameterdependent Lyapunov functions are proposed. Numerical examples are given to show the proposed conditions provide useful and less conservative results for the problems of H-two control with regional stability constraints.展开更多
The aim of this paper is to explore the concept of observability with constraints of the gradient for distributed parabolic system evolving in spatial domain Ω, and which the state gradient is to be observed only on ...The aim of this paper is to explore the concept of observability with constraints of the gradient for distributed parabolic system evolving in spatial domain Ω, and which the state gradient is to be observed only on a part of the boundary of the system evolution domain. It consists in the reconstruction of the initial state gradient which must be between two prescribed functions in a subregion Γ of Ω. Two necessary conditions are given. The first is formulated in terms of the subdifferential associated with a minimized functional, and the second uses the Lagrangian multiplier method. Nu-merical illustrations are given to show the efficiency of the second approach and lead to open questions.展开更多
针对近端策略优化(PPO)算法难以严格约束新旧策略的差异和探索与利用效率较低这2个问题,提出一种基于裁剪优化和策略指导的PPO(COAPG-PPO)算法。首先,通过分析PPO的裁剪机制,设计基于Wasserstein距离的信任域裁剪方案,加强对新旧策略差...针对近端策略优化(PPO)算法难以严格约束新旧策略的差异和探索与利用效率较低这2个问题,提出一种基于裁剪优化和策略指导的PPO(COAPG-PPO)算法。首先,通过分析PPO的裁剪机制,设计基于Wasserstein距离的信任域裁剪方案,加强对新旧策略差异的约束;其次,在策略更新过程中,融入模拟退火和贪心算法的思想,提升算法的探索效率和学习速度。为了验证所提算法的有效性,使用MuJoCo测试基准对COAPG-PPO与CO-PPO(PPO based on Clipping Optimization)、PPO-CMA(PPO with Covariance Matrix Adaptation)、TR-PPO-RB(Trust Region-based PPO with RollBack)和PPO算法进行对比实验。实验结果表明,COAPG-PPO算法在大多数环境中具有更严格的约束能力、更高的探索和利用效率,以及更高的奖励值。展开更多
基金supported in part by the NSFC-Zhejiang Joint Fund of the Integration of Informatization and Industrialization(U1609218)NSFC(61772312,61373078,61772253)+1 种基金the Key Research and Development Project of Shandong Province(2017GGX10110)NSF of Shandong Province(ZR2016FM21,ZR2016FM13)
文摘Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathematical formulation.However,poor performance of existing level set models on noisy images and weak boundary limit its application in image segmentation.In this paper,we present a region consistency constraint term to measure the regional consistency on both sides of the boundary,this term defines the boundary of the image within a range,and hence increases the stability of the level set model.The term can make existing level set models significantly improve the efficiency of the algorithms on segmenting images with noise and weak boundary.Furthermore,this constraint term can make edge-based level set model overcome the defect of sensitivity to the initial contour.The experimental results show that our algorithm is efficient for image segmentation and outperform the existing state-of-art methods regarding images with noise and weak boundary.
基金This work was supported by the Science Foundation of Education Commission of Hubei Province(No.D200613002)the Doctoral Pre-ResearchFoundation of Three Gorges University.
文摘This paper presents an improved method for H-two control with regional stability constraints for the closedloop system. The controller is given by the convex combination of a set of fixed gains. Both continuous and discrete-time systems in a known polytopic domain are investigated. New LMI-based sufficient conditions for the existence of parameterdependent Lyapunov functions are proposed. Numerical examples are given to show the proposed conditions provide useful and less conservative results for the problems of H-two control with regional stability constraints.
文摘The aim of this paper is to explore the concept of observability with constraints of the gradient for distributed parabolic system evolving in spatial domain Ω, and which the state gradient is to be observed only on a part of the boundary of the system evolution domain. It consists in the reconstruction of the initial state gradient which must be between two prescribed functions in a subregion Γ of Ω. Two necessary conditions are given. The first is formulated in terms of the subdifferential associated with a minimized functional, and the second uses the Lagrangian multiplier method. Nu-merical illustrations are given to show the efficiency of the second approach and lead to open questions.
文摘针对近端策略优化(PPO)算法难以严格约束新旧策略的差异和探索与利用效率较低这2个问题,提出一种基于裁剪优化和策略指导的PPO(COAPG-PPO)算法。首先,通过分析PPO的裁剪机制,设计基于Wasserstein距离的信任域裁剪方案,加强对新旧策略差异的约束;其次,在策略更新过程中,融入模拟退火和贪心算法的思想,提升算法的探索效率和学习速度。为了验证所提算法的有效性,使用MuJoCo测试基准对COAPG-PPO与CO-PPO(PPO based on Clipping Optimization)、PPO-CMA(PPO with Covariance Matrix Adaptation)、TR-PPO-RB(Trust Region-based PPO with RollBack)和PPO算法进行对比实验。实验结果表明,COAPG-PPO算法在大多数环境中具有更严格的约束能力、更高的探索和利用效率,以及更高的奖励值。
