4×1000m递增乳酸阈测试在国家皮划艇队备战伦敦奥运周期中的应用研究     

吴玉彪  田中 《湖北体育科技》2013,32(1):91-93

以国家队备战第30届奥运会的重点队员为研究对象,观察国家皮划艇队在备战伦敦奥运会周期的训练过程中如何应用4×1 000m测试对训练计划进行及时有效地监控和调整。结果表明运动员专项成绩提高明显,并在2012年奥运会上取得成绩。所以,在皮划艇训练中,4×1 000m测试对训练强度的监控和比赛成绩的提高具有重要意义。  相似文献   

R&D投资越多越好吗?——基于中国工业部门面板数据的门限回归分析     

孙晓华  辛梦依 《科学学研究》2013,31(3):377-385

R&D投资是转变经济发展方式和增强产业竞争力的关键,近年来随着我国研发经费支出的持续增加,作为要素投入的R&D投资是否越多越好成为亟待讨论的重要问题。本文以中国36个工业行业2002-2009年的面板数据为样本,利用门限回归模型检验了R&D投资对行业绩效的影响,来自全部工业行业数据的实证结果显示,R&D强度存在唯一的门限0.0089。分大类行业的估计结果表明:研发投资的作用机制在不同属性行业中存在明显差异,机械电子和资源加工业的R&D投资门限效应较为显著,且门限值(0.0125,0.0020)反映了行业生产的要素密集度特征;轻纺制造业由于R&D强度处于较低水平,不存在门限效应。  相似文献   

以SARS为例的传染病传播模型     

刘建清  王江荣  王庆龄  邹宏伟 《兰州石化职业技术学院学报》2006,6(4):27-29

以北京疫情的有关数据进行研究,给出SARS病毒传播的SIR模型.定义σ=(λ)/(δ)为接触数.并指出(1)/(σ)是模型SIR的一个阈值.给出了λ及σ的估计值.认为σ对疫情的发展及判断上起到非常重要的作用.利用一元线性回归及MATLAB数学软件拟合出模型中的几个初始值(S0,I0,R0)及参数值(λ,σ).并绘出S(t)、I(t)的相轨线,并对相轨线进行了分析,得到了满意的结果,为预防类SARS传染病及控制疫情发展提供较为可靠的依据.  相似文献   

Supervision learning as conceptual threshold crossing: when supervision gets ‘medieval’     

Susan Carter 《高等教育研究与发展》2016,35(6):1139-1152

This article presumes that supervision is a category of teaching, and that we all learn how to teach better. So it enquires into what novice supervisors need to learn. An anonymised digital questionnaire sought data from supervisors [n226] on their experiences of supervision to find out what was difficult, and supervisor interviews across campus [n7] sought to discover whether there were discipline differences among challenges. Findings suggest that supervision is often troublesome, and that lessons learned during supervision are irreversible, taking the learner to a deeper level of understanding, all aspects of threshold concept crossing. However, there was more that led me from threshold concept to conceptual threshold crossing theory: the darker themes of the data suggest that truly troublesome learning is more like that which occurs in early English literature, where threshold crossing is a common motif. Many early English stories show heroes in liminal, threshold spaces, often the forest, where their skills and methods are inadequate for ordeals. The result is their acquisition of what educational jargon might call leadership attributes and emotional intelligence. The title draws on Tarantino's [1994. Pulp fiction [Motion picture]. United States: Miramax Films] ‘getting medieval’ to mean threatening, unpleasant, off the edge of the known. Medieval English stories specialise in challenge: they focus on the doing, being and feeling of hard learning. When ongoing challenge from the unexpected troubles supervisors, it also enables, or forces, the acquisition of new attitudes, skills and attributes. I expand conceptual threshold crossing theory by adding the heuristic model of the medieval threshold crossing motif to interpret troublesome learning. Findings raise further research questions: how might novices avoid danger in the dark forest as they traverse their supervisory path and how can institutions support those who find themselves there.  相似文献   

MLMS算法的收敛性能和步长的研究     

候维岩  邓记才  汪敏  陈伯时 《上海大学学报(英文版)》2003,7(4):410-413

1　Introduction　Asanimportantadaptivealgorithm ,leastmeansquare (LMS)algorithmiswidelyusedinsignalpro cessingandcommunicationapplications[1,2 ] .Howev er ,itisdifficulttosetaproperstepsizeintheLMSalgorithm .Furthermore ,convergenceofthestandardLMSisslow[3] .Inordertosolvethesetwoproblems ,amodifiedleastmeansquare (MLMS)algorithmhasbeenpresented[4 ] .Intheliterature[4 ,6 ] ,ithasbeenpointedoutthatMLMSconvergeswithoutboundmeetingthereqirementofapproachingunbiasedesti mate .InRef.[5 ]ith…  相似文献   

Tunable polarization of high numerical-aperture objective with phase plate     

LI Jin-song  GAO Xiu-min  WANG Jian  LI Chen-xia 《重庆大学学报(英文版)》2007,6(2):125-129

The intensity distribution of depolarized field in the focal region of a high numerical-aperture optical system was investigated and found that the depolarization effect is tunable by the plate. The depolarization effect gains with the increase of the inner convergence angle of the phase plate, goes through a dramatic descent when the angle is larger than 30° and begins to come back when the angle reaches a threshold of respectively 60°and 65° for the orthogonal diffractive field and the longitudinal diffractive fields. This reveals two convergence points where the depolarization effect is the strongest and weakest, respectively, suggesting that the pure phase plate can be a promising method for altering depolarization diffractive fields and constructing optical instruments.  相似文献   

脉冲接种和具有双时滞的SEIR模型     

徐河苗 《长治学院学报》2012,29(2):40-44

讨论了一类脉冲接种和具有双时滞的SEIR模型,得到了其无病周期解。结果表明：接种率R＊〈1时,疾病消除;接种率R＊〉1时,疾病将成为地方病。  相似文献   

一种基于排列组合的视觉密码方案     

张慧  王洪君 《廊坊师范学院学报(自然科学版)》2012,12(6):7-10

视觉密码技术是近年来兴起的一种信息安全加密技术,为了得到一种简单有效的加密方法,可以从Naor和Shamir的视觉密码的基本思想出发,进行分析拓广,制定出一种基于排列组合原理的方案,基础矩阵构造根据每列中代表黑色像素的"1"的个数的变化选取。算法简单可行,易于操作,有实际意义。  相似文献   

突击创新的形成及对创新成果作用机制研究     

俞立平 《科技管理研究》2022,42(1):14-21

在界定突击创新概念的基础上,从理论上分析突击创新的形成机制以及对创新成果的作用机制,并基于中国高技术产业统计年鉴,综合采用面板数据模型、面板门槛模型、贝叶斯向量自回归模型进行实证,并基于BP人工神经网络模型进行稳健性检验.研究结果表明,突击创新的出现是一种必然,对科技成果具有明显的作用机制;突击创新对创新成果绩效显著;...  相似文献   

Social moderation,assessment and assuring standards for accounting graduates     

Kim Watty  Mark Freeman  Bryan Howieson  Phil Hancock  Brendan O’Connell  Paul de Lange 《Assessment & Evaluation in Higher Education》2014,39(4):461-478

Evidencing student achievement of standards is a growing imperative worldwide. Key stakeholders (including current and prospective students, government, regulators and employers) want confidence that threshold learning standards in an accounting degree have been assured. Australia’s new higher education regulatory environment requires that student achievements are benchmarked against intended programme learning outcomes, guided by published disciplinary standards and a national qualifications framework, and against other higher education providers. Here, we report on a process involving academics from 10 universities, aided by professional practitioners, to establish and equip assessors to reliably assure threshold learning standards in accounting that are nationally comparable. Importantly, we are learning more about how standards are interpreted. Based on the premise that meaning is constructed from tacit experiences, social interactions and intentional reflection on explicit information, we report outcomes of three multi-part calibration interventions, situated around judgements of the quality of the written communication skills exhibited in student work and their related assessment tasks. Qualitative data from 30 participants in the calibration process suggest that they perceive that the process both assists them both in developing a shared understanding of the accounting threshold learning standards and in the redesign of assessment tasks to more validly assess the threshold learning standards.  相似文献