二次曲线拟合算法的统计性能分析与改进     

杨忠根  姜桂祥  陈红亮 《上海海事大学学报》2003,24(1):46-51

传统的二次曲线拟合使用标准特征值分析算法。通过统计分析技术 ,可知该技术在拟合数字二次曲线时 ,存在估计偏差大、均方误差大的缺点。其产生原因是数据噪声的有色性和自相关函数矩阵的条件数过大 ,因此白化数据噪声和正则化变换是提高曲线拟合的有效措施。这从理论上有力地支持了Hartley提出的正则化算法。通过理论分析和计算机仿真实验 ,表明了降维EVD技术固有地同时具备噪声预白化功能和数据正则化功能 ,因此它能给出均方误差相当小的无偏估计。由于它无须进行预白化变换或正则化变换 ,并把最优化过程的维数从 6降为 2 ,所以它还具有计算快速、实现简单方便的优点。  相似文献   

体育科研三维方法述要(上)   总被引：1，自引：0，他引：1  

张洪潭 《体育与科学》2003,24(2):34-39

将常规的体育科研方法区分为三个相互关联的维度，其中，取材维含括观察、实验、假设三层阶，分别强调思考、目标、理论的不可或缺性；程序维依循一般思辨、专一选题、采集素材、整理素材、推理判断，验察修正六环节；课题维则从生物性学科和社会性学科两大方面寻求变革。最后还论及撰写文章十要点和缩减文字三要诀。  相似文献   

Research universities on the ResearchGate social networking site: An examination of institutional differences,research activity level,and social networks formed     

Weiwei Yan  Yin Zhang 《Journal of Informetrics》2018,12(1):385-400

As one of the largest active academic social networking sites, ResearchGate (RG) has been utilized by scholars to share publications, seek collaborators, communicate work in progress, and build scholarly reputation. This study collects data from RG users from 61 U.S. research universities at different research activity levels, as categorized by the Carnegie Classification of Institutions of Higher Education, to examine the impact of institutional differences on RG reputational metrics. The results confirm that RG is a research-oriented academic social networking site that closely and realistically mirrors the research activity level of institutions. With an increase in the research activity level of a university, its affiliated RG users tend to have higher RG scores, more publications and citations, and more profile views and followers, while the average number of reads of their publications and followees tend to be lower and fluctuant. In addition, RG users primarily follow others from institutions of a higher research activity level, forming virtual social networks centered around esteemed institutions. The study suggests academic social networks can serve as indicators in evaluation of research activities among research institutions, and such sites can be helpful and credible for acquiring resources, keeping informed about research, and promoting academic influence.  相似文献   

Proximal advantage in knowledge diffusion: The time dimension     

Jue Wang  Liwei Zhang 《Journal of Informetrics》2018,12(3):858-867

This paper intends to explore the impact of geographic proximity on the diffusion of knowledge in the form of publication citations, and argues that codified knowledge is transmitted faster in proximity and is subject to similar geographic constraints as tacit knowledge. The geographic proximity advantage would be particularly relevant in the early stage of dissemination. We collected three sets of research articles published in 1990, 2000 and 2010 and compared the longitudinal citations they received domestically and from abroad. The study found that domestic citations accumulate faster and reach their peak much earlier than foreign citations, and the difference is most evident in the first few years after publication. The result shows that geographic proximity does play a role in the speed of knowledge diffusion and points to the network effect for citations. Those located closer to the knowledge origin would be exposed and react to publications faster due to the additional opportunities of research exchange and network.  相似文献   

浅论科学研究对医院发展的贡献     

曹天然  聂瑛洁 《教育文化论坛》2020,12(3):112-115

采用文献研究法、定性分析法和定量分析法,对目前国内外部分医院科研现状进行分析,总结医院的科研现状和发展规律,分析医院科研对医院的贡献,为提高医院科研水平提供参考依据。结果表明:医院科研给医院带来的贡献包括科研产出和科研声誉;医院开展科研,在SCI发文量和专利获得量上,给医院带来了巨大的贡献;同时,良好的科研会提高医院在医院排行榜上的位置,提高医院声誉。  相似文献   

Global dimension of weak smash product     

JIA Ling LI Fang 《浙江大学学报(A卷英文版)》2006,7(12):2088-2092

INTRODUCTION In (Auslander, 1995), the author established the relationship of homological dimension between skew group algebra ΛG and Λ. Recall from Corollary 4.7 and Corollary 4.10 in (Auslander, 1995) that gl.dim(ΛG)=gl.dim(Λ) where ΛG is a skew group algebra with the order of G invertible in Λ. Recently, more and more mathematicians have studied homological dimension for Hopf algebra. Yang (2002) gave the relationship of homological dimension between smash product algebra A#H…  相似文献   

A Publisher Perspective: How One Publisher is Responding to the Changing World of Scholarly Communication     

Jayne Marks  Chris Bulock 《期刊图书馆员》2016,70(1-4):7-13

For this talk, Marks was tasked with summarizing the important trends in scholarly publishing in 45 minutes. The speaker reflected on the rapid changes that have occurred in journal publishing, which followed more than 300 years of relatively slow progress. Marks discussed key technology trends such as data curation, Open Access (OA) mandates, and the changes occurring in the global landscape of scholarly communications and library budgets. Wolters Kluwer Health has been responding to these trends with new publishing experiments including a Platinum OA model in emerging markets. Marks discussed the ways that publishers and libraries need to alter their traditional practices and instill a focus on their customers and communities.  相似文献   

诚信如节,市场和谐——社会主义市场经济下的诚信精神     

尹田生 《黄冈职业技术学院学报》2003,5(4):9-10

诚信精神是基本道德规范,是社会主义市场经济有序运行的重要条件。必须大力培育诚信精神  相似文献   

新时代高校辅导员工作理念转变的三个维度     

庞德英  祝晓斐 《高校辅导员学刊》2019,11(2):14-18

中国特色社会主义进入新时代为高校思想政治工作带来了新的起点,面对党和国家对思想政治工作的新要求,面对大学生成长发展的新期待,高校辅导员要从三个维度转变工作理念:从灌输走向对话,努力做大学生政治思想的积极引导者;从管理走向服务,努力做大学生成长成才的科学指导者;从经验走向研究,努力做大学生思想政治教育的潜心研究者。  相似文献   

用幻方引进向量空间—德国数学建模实例     

杨军  张明善 《涪陵师范学院学报》2002,18(5):67-68

用幻方作为一种具体的向量模型，直观引入向量空间的基本概念，反过来又用高观点指导幻方结构的研究。  相似文献