Comparing apples with oranges? An approach to link TIMSS and the National Educational Panel Study in Germany via equipercentile and IRT methods     

《Studies in Educational Evaluation》2015

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A multi-class large margin classifier     

Liang Tang  Qi Xuan  Rong Xiong  Tie-jun Wu  Jian Chu 《浙江大学学报(A卷英文版)》2009,10(2):253-262

Currently there are two approaches for a multi-class support vector classifier （SVC）. One is to construct and combine several binary classifiers while the other is to directly consider all classes of data in one optimization formulation. For a K-class problem （K〉2）, the first approach has to construct at least K classifiers, and the second approach has to solve a much larger optimization problem proportional to K by the algorithms developed so far. In this paper, following the second approach, we present a novel multi-class large margin classifier （MLMC）. This new machine can solve K-class problems in one optimization formulation without increasing the size of the quadratic programming （QP） problem proportional to K. This property allows us to construct just one classifier with as few variables in the QP problem as possible to classify multi-class data, and we can gain the advantage of speed from it especially when K is large. Our experiments indicate that MLMC almost works as well as （sometimes better than） many other multi-class SVCs for some benchmark data classification problems, and obtains a reasonable performance in face recognition application on the AR face database.  相似文献   

利用淘汰的大容量电池组改装UPS电源     

程皞琳 《大众科技》2012,(5):116-118

随着广播电视事业的发展,对安全播出的要求不断提高,这样不间断电源UPS就越来越需要。但由于各种原因,某发射台一直没有配备UPS电源。2009年由于全省微波数字化改造完成,原有的微波设备被淘汰,其中包含有大容量的蓄电池组,利用其和原有的直流屏组合可稳定的输出24V直流电,据此将它们改装为一个输出220V工频交流电的UPS电源,供信号机房内重要的信号源设备使用,提高了安全播出的可靠性。  相似文献   

The innovation potential of new infrastructure development: An empirical study of Heathrow airport's T5 project     

Nuno Gil  Marcela MiozzoSilvia Massini 《Research Policy》2012,41(2):452-466

We propose a conceptual framework to analyze technology adoption in mega infrastructure projects, and assess their potential to innovating large socio-technical systems. Drawing on an in-depth empirical analysis of Heathrow airport's Terminal 5 project, we find that innovation hinges on technology adoption decisions that are governed systematically by two intertwined determinants - assessment of expected profitability and development of absorptive capacity, both of which are distributed across various interdependent actors. On an ad hoc basis, technological decisions are also affected by other factors, namely attitudes toward risk, politics, and (lack of) established standards. We reveal how a schedule-driven project framing creates an underlying boundary condition that constrains the longitudinal process of building a ‘whole collective’ with capacity to absorb new technologies. The innovation potential of mega projects is thus subjected to a fundamental, unifying tension: on the one hand, they offer a one-off opportunity to invest in cutting-edge technologies and innovate socio-technical systems; on the other hand, project stakeholders have limited time to develop capacity to absorb novel technologies and negotiate differences on assessments of profitability and risk. Stakeholders may therefore be compelled to agree to adopt proven technologies upfront to reduce uncertainty and mitigate risks, thus limiting the innovation potential of new infrastructure development.  相似文献   

重大科技基础设施预先研究管理解析及思考     

樊潇潇  李泽霞  宋伟  陈娟 《科技管理研究》2019,39(2)

重大科技基础设施是国家科技强国发展战略的重要技术支撑。预先研究一直是我国设施建设和发展的薄弱环节,严重制约着我国设施实现从跟跑到并跑、领跑的跨越发展。这篇文章通过对我国设施建设项目郭守敬望远镜以及500米口径球面射电望远镜两个实例,分析预先研究阶段对于顺利完成工程建设的重要性。且通过对美国国家基金会以及欧洲科技基础设施战略论坛对于设施预先研究的管理及投资情况,剖析国外设施预先研究阶段管理要点。在此基础上提出要高度重视设施预先研究工作,建议建立适宜设施可持续发展的预先研究管理体制机制。  相似文献   

德国重大科技基础设施路线图制定与启示     

樊潇潇  李泽霞  宋伟  吕琨 《科技管理研究》2019,39(8)

重大科技基础设施作为国家的重要战略科技力量,深化研究设施发展战略、科学制定设施规划对实现国家总体发展目标具有重要意义。这篇文章深入解读了德国在制定本国重大科技基础设施发展路线图的研究方法以及管理要点,并提出了关于准确把握重大科技基础设施内涵、以及优化我国设施规划制定程序等问题的思考,以期对国家制定重大科技基础设施发展战略和规划提供借鉴。  相似文献   

基于数据实证的大型科学仪器共享单位内置属性研究     

吴斌  李鑫  邬平  马继涛  邓艺 《科技管理研究》2019,39(15)

为找出大型仪器共享服务过程中影响仪器管理单位实施共享服务的“内置属性”,以云南省大型科学仪器开放共享管理平台共享服务记录数据为实证基础,利用复杂网络的连出度、连接权值、服务频次等指标项分析大型仪器管理单位的内生需求、定向服务需求和对外服务需求,获得大型仪器共享单位服务对象属性矩阵。基于服务对象属性矩阵,定量分析了以市场需求、教育科研和公共服务为不同职能目标的大型仪器共享服务单位所提供仪器共享服务的需求成分,获得了仪器管理单位不同的内置属性,为大型科学仪器共享管理制度以及共享服务绩效考评指标的制定提供依据和参考。  相似文献   

初中武术单元教学实验研究   总被引：3，自引：0，他引：3  

林越英陈涵  徐志诚 《福建体育科技》2002,21(4):62-64

本文就我国学校体育课教学普遍实行的小单元教学产生的弊病和大单元的实施问题进行探讨 ,并针对我省中学体育实验教材 ,武术教学内容大单元在教学实践中进行实验 ,两者学生相比 ,各项差异显著。  相似文献   

一种对数据库进行压缩的关联规则挖掘算法     

赵伟 《科技广场》2005,(10):8-12

关联规则挖掘算法为了发现事先未知的关联规则,需要用高效的方法计算出数据库中的大项目集。影响数据挖掘效率的两个因素,一个是数据库大小,另一个是算法的效率。本文算法通过将数据库进行高度压缩,使数据库中的数据量大大减少,同时算法采用逻辑运算方法计算项集的支持数,计算效率较高。  相似文献   

《运动生理学》大班教学有效性探讨     

郭玉萍 《安阳师范学院学报》2011,(2):154-156

高校招生规模的扩大和教育资源发展的相对滞后,使得很多课程处于大班教学环境。大班教学中存在很多教学不利条件,只有更新教学理念,采取有效的教学组织方式才能够克服这些潜在的不利因素,提高课堂教学的效果。  相似文献