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Comparison of parametric sparse recovery methods for ISAR image formation

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Science China(Information Sciences) 2014年第2期57卷 157-168页

作者： RAO Wei LI Gang wang xiqin XIA XiangGen Department of Electronic Engineering Tsinghua University Department of Electrical and Computer Engineering University of Delaware Department of Electronic Engineering Chonbuk National University

A parametric sparse representation model of the inverse synthetic aperture radar(ISAR)signal has been proposed recently,and the ISAR signal is decomposed as a summation of many basis-signals determined by the target rotation *** on the parametric sparse representation model,several sparsity-driven algorithms are proposed to retrieve both the target rotation rate and the ISAR *** this paper,four parametric sparse recovery algorithms are compared mainly in three aspects:the accuracy of the rotation rate estimation,the ISAR image quality and the computational *** examples are presented to show the advantages and disadvantages for each method.

关键词： ISAR imaging parametric sparse representation adaptive sparse recovery matching pursuit

Water quantity-quality combined evaluation method for rivers＇ water requirements of the instream environment in dualistic water cycle： A case study of Liaohe River Basin

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Journal of Geographical Sciences 2007年第3期17卷 304-316页

作者： wang xiqin ZHANG Yuan LIU Changming School of Natural Resources and Environment Renmin University of China Beijing 100872 China River and Coastal Environmental Research Center Chinese Research Academy of Environmental Sciences Beijing 100012 China Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Key Laboratory for Water and Sediment Sciences of the Ministry of Education Beijing Normal University Beijing 100875 China

In this article the meaning of the quantity and quality of environmental flows of river in dualistic water cycle is discussed, and compared with the meaning of unitary water cycle. Based on the analysis of the relationship between environmental flows of river requirements, the efficiency of water resource usage, the consumption coefficient, and the concentration of waste water elimination, the water quantity and water quality calculation method of the environmental flows of river requirements in dualistic water cycle is developed, and the criteria for environmental flows of river requirements are established, and therefore the water quantity-quality combined evaluation of natural river flows requirements are realized Taking the Liaohe River as a model, the environmental flows of river requirements for Xiliao River, Dongliao River, mainstream Liaohe River, Huntai River and northeast rivers along the coasts of the Yellow and Bohai seas in unitary water cycle are calculated, each taking up 39.3%, 63.0%, 43.9%, 43.3% and 43.5% of runoff respectively. Evaluated according to Tennant recommended flow, the results show that： except Xiliao River is ＂median＂, the rest are all upon ＂good＂, the Dongliao River is even ＂very good＂. The corresponding results in dualistic water cycle are that, the proportion of natural flows for each river is 57.5%, 74.1%, 60.8%, 60.3% and 60.4%; while the combined evaluation results show that： considering ＂quantity＂, except Xiliao River, the rest rivers can all achieve the ＂quantity＂ criteria of the en- vironmental flows of river requirements, but if considering the aspect of ＂quality＂, only Dongliao River can reach the ＂quality＂ standard. By water quantity-quality combined evaluation method, only Dongliao River can achieve the criteria. So the water quality is the main factor that determines whether the environmental flows can meet the river ecosystem demands.

关键词： dualistic water cycle rivers environmental flows of river requirements water quantity water quality evaluation Liaohe River

Evaluation of harmonious development for economy-environment system in coastal cities: a case study of Tianjin Municipality

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Ecological Economy 2006年第2期2卷 152-160页

作者： Li Fen Zhang Yuan Zheng Binghui wang xiqin School of Environment and Natural Resources Renmin University of China Beijing 100873 P. R. China River and Coastal Environmental Research Center. Chinese Research Academy of Environmental Sciences. Beijing 100012. P. R. China

With the aim of the harmonious development of economy-environment system in coastal cities in China. an index ,system used to evaluate the economy-environment system is built up in this paper, which includes four aspects： economy, environment, resources, and ocean industry. Based on the analysis on present condition and future trends of economic development in Tianjin and the quantification of various evaluation indices, the aathor applies integrated index valuation model to valuate the harmonious development af economy-environment of Tianjin. The results show that the coordinated degree of economy-environment would drop down in the future, from 0.95（superior level of harmonious development） in 2000 to 0.59（inferior level of harmonious development） in 2015. under the circumstance of the current economic development mode. The level of comprehensive development of Tianjin also presents to descend. Based on the analyzing of status and future trends of environment-economy coordinated development, the paper puts forward the countermeasures such as industry, structure adjustment, increasing the level of environmental protection investment, strengthening the enforcement of en vironmental policies to improve the coordinated development of environment-economy in Tianjin municipality.

关键词： Coastal cities Economy-environment system Harmonious development Coordination degree Tianjin Municipality

Weak key analysis for chaotic cipher based on randomness properties

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Science China(Information Sciences) 2012年第5期55卷 1162-1171页

作者： YIN RuMing,wang Jian,YUAN Jian,SHAN XiuMing & wang xiqin Department of Electronic Engineering,Tsinghua University,Beijing 100084,China 1. Department of Electronic Engineering Tsinghua University Beijing 100084 China

Weak key analysis is a key issue in the design of chaotic *** most of the existing research focusing on the degradation of the chaotic sequences which causes weak keys,we point out that the parameters for which the chaotic sequences do not degrade are still possible to be weak *** this paper,we propose a new approach based on the rigorous statistical test to improve the weak key *** weak keys of a specific chaotic cipher are investigated by using our method and a large number of new weak keys are *** results verify that our method is more *** the other hand,although statistical tests are now widely adopted to test the chaos-based bit sequences,there are few reports of analysis results on the weak keys or weak sequences of chaotic *** our work may be helpful for current research on statistical tests of chaotic cipher.

关键词： chaos cryptography statistical test weak keys sequence randomness

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教育科技人才一体化发展(笔谈)

中国高教研究 2024年第9期 1-12页

作者：林蕙青管培俊李家俊王希勤张来斌张大良孙维杰李楠李志民马陆亭中国高等教育学会国家自然科学基金委员会《中国高教研究》编辑委员会中国高等教育学会碳中和与清洁能源教育专业委员会中国工程院中国高等教育学会监事会中国高等教育学会科技服务专家指导委员会中国高等教育学会学术发展咨询委员会

党的二十届三中全会是在以中国式现代化全面推进强国建设、民族复兴伟业的关键时期召开的一次十分重要的会议。全会通过的《中共中央关于进一步全面深化改革、推进中国式现代化的决定》为进一步全面深化改革、推进中国式现代化作出了系... 详细信息

党的二十届三中全会是在以中国式现代化全面推进强国建设、民族复兴伟业的关键时期召开的一次十分重要的会议。全会通过的《中共中央关于进一步全面深化改革、推进中国式现代化的决定》为进一步全面深化改革、推进中国式现代化作出了系统部署。全会提出统筹推进教育科技人才体制机制一体改革,为加快建设教育强国、科技强国、人才强国指明了方向。为深入学习贯彻、研究阐释党的二十届三中全会精神,8月1日,中国高等教育学会召开了“学习贯彻党的二十届三中全会精神,推进教育科技人才三位一体协同融合发展”座谈会,教育领域的专家学者围绕座谈会主题深入探讨全会关于教育科技人才的新思想、新论断,本刊特开设“学习贯彻党的二十届三中全会精神”专栏,精选发言人的观点摘编,以期为教育领域深入学习全会精神、贯彻落实党中央决策部署提供参考,深刻把握教育强国建设面临的新形势,推进教育科技人才三位一体协同融合发展,为实现中国式现代化贡献力量。

关键词：科技人才教育强国中国式现代化科技强国人才强国协同融合强国建设三位一体

Ethnopharmacology,chemical composition and functions of Cymbopogon citratus

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Chinese Herbal Medicines 2024年第3期16卷 358-374页

作者： xiqin Du Meng Zhang Shuping wang Jingyang Li Jingze Zhang Dailin Liu Tianjin University of Traditional Chinese Medicine Tianjin 301617China Tianjin Modern Innovation Chinese Medicine Technology Co. Ltd.Tianjin 300380China Characteristic Medical Center of Chinese People’s Armed Police Force Tianjin 300300China Department of Pharmacy Logistics College of Chinese People’s Armed Police ForceTianjin 300309China

Cymbopogon citratus in the gramineous family,also known as lemongrass(LG),is a perennial ***,a drug and food homologous medicine,has a widely recorded medicinal value and food *** date,158 LG compounds have been reported,including terpenoids,flavonoids,phenolic *** and clinical studies have indicated that LG has antibacterial,neuroprotective,hypoglycemic,hypotensive,anti-inflammatory,and anti-tumor *** article reviews LG in ethnopharmacology,chemical composition,pharmacology,food,medicine,and daily chemical applications to provide a basis for the subsequent development of food and medicine.

关键词： chemical composition Cymbopogon citratus(DC.)Stapf drug and food homologous medicine ethnopharmacology lemongrass medicine and food applications

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自适应中心加权的改进均值滤波算法

清华大学学报（自然科学版） 1999年第9期39卷 76-78页

作者：张宇王希勤彭应宁清华大学电子工程系信号检测教研组北京100084

为了在滤除退化图像中混合噪声的同时能更好地保护图像的细节，文中提出了基于改进均值滤波（ＭＴＭ）结构的新算法，其特点为：１）用中心加权中值滤波算法替代ＭＴＭ方法中的中值滤波算法以更好地保护细节；２）提出了一... 详细信息

为了在滤除退化图像中混合噪声的同时能更好地保护图像的细节，文中提出了基于改进均值滤波（ＭＴＭ）结构的新算法，其特点为：１）用中心加权中值滤波算法替代ＭＴＭ方法中的中值滤波算法以更好地保护细节；２）提出了一种直接利用滤波结果来估计混合噪声中高斯噪声方差的方法，估计的结果被用于滤波器系数的调整，使得新算法有很好的鲁棒性。实践证明新方法的处理结果优于传统的ＭＴＭ

关键词：中心加权自适应图像处理噪声均值滤波算法

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一种用于夜间图像增强的算法

清华大学学报（自然科学版） 1999年第9期39卷 79-80页

作者：张宇王希勤彭应宁清华大学电子工程系信号检测教研组北京100084

为了提高夜间图像的清晰度，文中提出了一种适用于此类图像增强的新算法，其特点为：１）将对比度增强算法与直方图均衡算法级联，使得图中的局部信息与全局信息在增强时都能被利用；２）经对各种函数的实际处理效果进行比较，提出... 详细信息

为了提高夜间图像的清晰度，文中提出了一种适用于此类图像增强的新算法，其特点为：１）将对比度增强算法与直方图均衡算法级联，使得图中的局部信息与全局信息在增强时都能被利用；２）经对各种函数的实际处理效果进行比较，提出了一个适合夜间图像增强的对比度变换函数。

关键词：图像增强灰度变换对比度增强夜间图像清晰度

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教育的全面性

中国高教研究 2023年第9期 3-5,8页

作者：王希勤清华大学北京100084 中国高等教育学会北京100191

教育的基本问题是个体发展与社会发展的关系问题。教育是在一个系统中发展的,与国家的发展具有统一性。我们党和国家主张把人的全面发展与社会全面进步相统一,强调教育的全面性,这是中国教育的价值取向。与我们党和国家教育方针不同,以... 详细信息

教育的基本问题是个体发展与社会发展的关系问题。教育是在一个系统中发展的,与国家的发展具有统一性。我们党和国家主张把人的全面发展与社会全面进步相统一,强调教育的全面性,这是中国教育的价值取向。与我们党和国家教育方针不同,以美国为代表的西方教育理念具有片面性。当今时代从教育的全面性反思大学的使命,需要构建更具全面性的教育体系。要坚定教育自信,坚守全面性的价值取向,反对简单的“个体本位论”或“社会本位论”,主张“人的全面发展与社会全面进步相统一”;坚持对教育的逻辑体系做完备的分析,反对止步于“个体的原子化”和“培养公民的通识教育”,主张“人的全面素质(德智体美劳)和人的全面角色(功利性加超越性)相统一”。

关键词：人的全面发展社会全面进步教育全面性