扇区划分是平衡管制员工作负荷、提升空域通行能力的有效技术措施。采用Voronoi图自顶向下切割空域的方法具有自动保证扇区凸性、连通性和压缩性的特性,但计算时间过长。根据航迹状态计算工作负荷,构建了Voronoi图自顶向下切割空域模型...扇区划分是平衡管制员工作负荷、提升空域通行能力的有效技术措施。采用Voronoi图自顶向下切割空域的方法具有自动保证扇区凸性、连通性和压缩性的特性,但计算时间过长。根据航迹状态计算工作负荷,构建了Voronoi图自顶向下切割空域模型,设计了动态步长蚁群搜索算法。测试结果表明,在太原高空划分成4个扇区的情况下,与MC-CLFV(Monte Carlo method by changing location of flexible vertices)算法相比较,采用动态步长蚁群搜索算法求解,扇区的不平衡性显著减少,总工作负荷也减少了11.2%。大规模重复实验表明,随扇区数量增加,解的质量差异减少,但解的效率差异却不断增大,划分8个扇区时,动态步长蚁群搜索算法的计算时间统计中位数值仅为MC-CLFV算法的1/10。这说明该算法在一次划分数量少的时候,质量高而且计算时间短,在采用多层规划扇区的时候,应该采用组合数字和较小的划分方案。研究结果为采用Voronoi图直接切割空域形成管制扇区奠定了基础。展开更多
In this paper,a novel zero-watermark copyright authentication scheme based on Internet public certification system is proposed.This approach utilizes Haar integer wavelet transform based on a lifting scheme and adapti...In this paper,a novel zero-watermark copyright authentication scheme based on Internet public certification system is proposed.This approach utilizes Haar integer wavelet transform based on a lifting scheme and adaptive Harris corner detection to extract image features,which will be used to produce a binary feature map,and the map is very crucial to the generation of watermark registered later.By properly choosing the parameters of aforementioned techniques such as the threshold T and the radius of local feature region R,the feature map is so much more stable and distinguishing that it can be used to construct robust watermark.Simulations demonstrate that the proposed scheme is resistant to many kinds of signal processing and malicious attacks such as Gaussian blurring,additive noising,JPEG lossy compression,cropping,scaling and slight rotation operation.Compared with a relative scheme such as that of Chang＇s,the scheme in this paper is more practicable and reliable and can be applied to the area of copyright protection.展开更多
文摘扇区划分是平衡管制员工作负荷、提升空域通行能力的有效技术措施。采用Voronoi图自顶向下切割空域的方法具有自动保证扇区凸性、连通性和压缩性的特性,但计算时间过长。根据航迹状态计算工作负荷,构建了Voronoi图自顶向下切割空域模型,设计了动态步长蚁群搜索算法。测试结果表明,在太原高空划分成4个扇区的情况下,与MC-CLFV(Monte Carlo method by changing location of flexible vertices)算法相比较,采用动态步长蚁群搜索算法求解,扇区的不平衡性显著减少,总工作负荷也减少了11.2%。大规模重复实验表明,随扇区数量增加,解的质量差异减少,但解的效率差异却不断增大,划分8个扇区时,动态步长蚁群搜索算法的计算时间统计中位数值仅为MC-CLFV算法的1/10。这说明该算法在一次划分数量少的时候,质量高而且计算时间短,在采用多层规划扇区的时候,应该采用组合数字和较小的划分方案。研究结果为采用Voronoi图直接切割空域形成管制扇区奠定了基础。
基金Supported by the National Natural Science Foundation of China (60873117)the Key Program of Natural Science Foundation of Tianjin (07JCZDJC06600)
文摘In this paper,a novel zero-watermark copyright authentication scheme based on Internet public certification system is proposed.This approach utilizes Haar integer wavelet transform based on a lifting scheme and adaptive Harris corner detection to extract image features,which will be used to produce a binary feature map,and the map is very crucial to the generation of watermark registered later.By properly choosing the parameters of aforementioned techniques such as the threshold T and the radius of local feature region R,the feature map is so much more stable and distinguishing that it can be used to construct robust watermark.Simulations demonstrate that the proposed scheme is resistant to many kinds of signal processing and malicious attacks such as Gaussian blurring,additive noising,JPEG lossy compression,cropping,scaling and slight rotation operation.Compared with a relative scheme such as that of Chang＇s,the scheme in this paper is more practicable and reliable and can be applied to the area of copyright protection.
