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Research Progress on Discretization of Linear Canonical Transform
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作者 Yannan Sun bingzhao li Ran Tao 《Journal of Beijing Institute of Technology》 EI CAS 2021年第3期205-216,共12页
Linear canonical transformation(LCT)is a generalization of the Fourier transform and fractional Fourier transform.The recent research has shown that the LCT is widely used in signal processing and applied mathematics,... Linear canonical transformation(LCT)is a generalization of the Fourier transform and fractional Fourier transform.The recent research has shown that the LCT is widely used in signal processing and applied mathematics,and the discretization of the LCT becomes vital for the applic-ations of LCT.Based on the development of discretization LCT,a review of important research progress and current situation is presented,which can help researchers to further understand the discretization of LCT and can promote its engineering application.Meanwhile,the connection among different discretization algorithms and the future research are given. 展开更多
关键词 linear canonical transform(LCT) discrete linear canonical transform sampling Wign-er-Ville distribution fast algorithm
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中国乳腺癌自然史参数选择的优化方法
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作者 尹娟 王乐 +7 位作者 白晓宁 李燕婕 王鑫 张在坤 李炳照 李扬 石菊芳 李庆娜 《中国科学:数学》 CSCD 北大核心 2023年第6期895-913,共19页
乳腺癌是女性最常见的恶性肿瘤之一。为了提出有效的筛查策略并评估其效果,一个基本且重要的步骤是在中国乳腺癌自然史模型中选择合适的参数,即转移概率.选择合理的转移概率有两个挑战.首先,由于乳腺癌的流行病学特性,其他国家使用的转... 乳腺癌是女性最常见的恶性肿瘤之一。为了提出有效的筛查策略并评估其效果,一个基本且重要的步骤是在中国乳腺癌自然史模型中选择合适的参数,即转移概率.选择合理的转移概率有两个挑战.首先,由于乳腺癌的流行病学特性,其他国家使用的转移概率不一定适用于中国.其次,可用的筛查样本数据很少,这使得传统的基于统计的方法(如极大似然估计法)失效.本文从优化角度提出一种乳腺癌自然史参数选择的方法,基于公布的统计数据建立数学优化模型.该模型的挑战在于目标函数高度非线性且无显式表达式,本文提出一种坐标下降算法来处理这个挑战.最后,本文提出一种最佳匹配方法来估计每个转移概率的分布.本文所提出的方法为进一步提出合理的中国乳腺癌筛查策略和分析乳腺癌的经济负担提供了坚实的基础. 展开更多
关键词 乳腺癌 自然史 参数选择黄金分割法 无导数法 坐标下降法
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基于多活性代理的人工系统架构调整方法
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作者 赵志纯 李炳照 +1 位作者 胡进 王越 《中国科学:信息科学》 CSCD 北大核心 2019年第12期1559-1571,共13页
在现实动态强对抗强约束的社会环境下,固化的人工系统架构通常无法满足复杂多变的服务任务需求.本文根据多活性代理系统理论,增强管理者的管控作用,通过替换主代理或增加新的活性代理,对系统架构进行调整,使人工系统的活性自组织机理机... 在现实动态强对抗强约束的社会环境下,固化的人工系统架构通常无法满足复杂多变的服务任务需求.本文根据多活性代理系统理论,增强管理者的管控作用,通过替换主代理或增加新的活性代理,对系统架构进行调整,使人工系统的活性自组织机理机能发生改变,使环境对抗矛盾发生转变占据主导地位,系统功能活性得以保持和提升,以满足任务需求.本文首先对多活性代理系统理论进行了简要回顾,然后提出了基于多活性代理的人工系统架构调整方法,最后以对抗美制P2V-7侦察机入侵的防空系统为实例对所提方法的有效性进行了验证. 展开更多
关键词 多活性代理系统理论 人工系统 活性代理 系统架构调整 活性度
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Real-time,in situ probing of gamma radiation damage with packaged integrated photonic chips 被引量:1
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作者 QINGYANG DU JEROME MICHON +8 位作者 bingzhao li DEREK KITA DANHAO MA HAIJIE ZUO SHAOliANG YU TIAN GU ANURADHA AGARWAL MO li JUEJUN HU 《Photonics Research》 SCIE EI CSCD 2020年第2期186-193,共8页
Integrated photonics is poised to become a mainstream solution for high-speed data communications and sensing in harsh radiation environments,such as outer space,high-energy physics facilities,nuclear power plants,and... Integrated photonics is poised to become a mainstream solution for high-speed data communications and sensing in harsh radiation environments,such as outer space,high-energy physics facilities,nuclear power plants,and test fusion reactors.Understanding the impact of radiation damage in optical materials and devices is thus a prerequisite to building radiation-hard photonic systems for these applications.In this paper,we report real-time,in situ analysis of radiation damage in integrated photonic devices.The devices,integrated with an optical fiber array package and a baseline-correction temperature sensor,can be remotely interrogated while exposed to ionizing radiation over a long period without compromising their structural and optical integrity.We also introduce a method to deconvolve the radiation damage responses from different constituent materials in a device.The approach was implemented to quantify gamma radiation damage and post-radiation relaxation behavior of SiO2-cladded SiC photonic devices.Our findings suggest that densification induced by Compton scattering displacement defects is the primary mechanism for the observed index change in SiC.Additionally,post-radiation relaxation in amorphous SiC does not restore the original pre-irradiated structural state of the material.Our results further point to the potential of realizing radiation-hard photonic device designs taking advantage of the opposite signs of radiation-induced index changes in SiC and SiO2. 展开更多
关键词 SCATTERING DAMAGE RELAXATION
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