英文科技文献内核识别方法研究     

祝清松  冷伏海  王林  韩涛 《情报理论与实践》2012,35(9):112-116

针对英文科技文献的特征,提出一种规则和统计相结合的关键内容识别方法。该方法首先通过对源文档进行特征标识,将其转换成更易于处理的中间文档;然后利用特征还原、线索词匹配、主题识别和临近分析等,从中间文档抽取代表文本的主要信息,生成目标文档。该方法能够有效地辅助科研人员阅读大量的英文科技文献,提高阅读效率。  相似文献   

基于云计算的生物DNA指纹图谱大范围比对方法     

张文静 《科技通报》2012,28(6):92-95

针对DNA特征比对过程中,产生的生物DNA特征图谱特征较为复杂,生物特征极为琐碎,海量生物DNA特征的对比,依然是一项十分复杂的工作。传统算法多是基于单个DAN特征进行车轮式对比。一旦生物特征过于繁琐,造成比对匹配耗时,效率较低。本文提出了一种基于云计算的生物DNA特征海量数据对比技术。建立云计算网络模型,计算生物DNA泳道特征系数,将DNA限制性片断形成的谱带从背景中分离出来,完成海量DNA数据对比。实验证明,这种算法能够避免由于DNA图谱数量过大造成的匹配耗时缺点,提高了生物DNA指纹图谱大范围比对的效率。  相似文献   

电脑测配色系统的应用     

贡建宏 《科学中国人》2012,34(9)

简述了电脑测配色的基本工作原理及在实际工作中的应用,如色样准确性的控制和提供品管测色报告,利用配色软件选配较好的处方来方便快捷的解决同色异谱现象,有效提高了打样的效率。同时指出了电脑测配色在使用时的不足及解决方法。  相似文献   

论罪责刑相适应原则在刑法适用解释中的作用——以一起转化型抢劫案为视角     

张健 《涪陵师专学报》2010,(5):88-90

罪责刑相适应原则作为刑法的基本原则之一,在刑法中具有全局性的指导作用。当一个行为被认定为犯罪后,罪责刑相适应原则不仅能影响量刑,使得刑罚与犯罪相适应;在一些典型案件中根据犯罪可能判处的刑罚还可能影响定罪,从而做到罪责刑相适应。只有以罪责刑相适应原则为指导,才能正确地进行刑法的适用解释,进而合理地适用刑法。  相似文献   

基于加权XML模型的XML数据与DTD模式匹配*     

李树青程国达  王维民 《现代图书情报技术》2010,26(1):57-65

首先说明利用加权XML数据模型分别得到标准XML参考实例和XML数据实例的方法,并对DTD约束修饰符的表达方法进行介绍。其次,详细阐述相似度算法的实现方法,重点说明在XML数据实例中寻找与标准XML参考实例的匹配节点算法和计算标准 XML参考实例与XML数据实例的相似度算法。最后,对相关实验及其结论进行总结。  相似文献   

An Evaluation of Latent Growth Models for Propensity Score Matched Groups     

Walter L. Leite  Robert Sandbach  Rong Jin  Jann W. MacInnes  M. Grace-Anne Jackman 《Structural equation modeling》2013,20(3):437-456

Because random assignment is not possible in observational studies, estimates of treatment effects might be biased due to selection on observable and unobservable variables. To strengthen causal inference in longitudinal observational studies of multiple treatments, we present 4 latent growth models for propensity score matched groups, and evaluate their performance with a Monte Carlo simulation study. We found that the 4 models performed similarly with respect to model fit, bias of parameter estimates, Type I error, and power to test the treatment effect. To demonstrate a multigroup latent growth model with dummy treatment indicators, we estimated the effect of students changing schools during elementary school years on their reading and mathematics achievement, using data from the Early Childhood Longitudinal Study Kindergarten Cohort.  相似文献   

试论广告设计的色彩搭配     

蔚小燕 《山西广播电视大学学报》2013,(4):60-62

色彩的巧妙运用是现代广告设计中不可缺少的因素,它在广告中具有重要的艺术功能,能更好地阐述广告要表达的内涵,文章从分析色彩与消费者的感官心理出发,阐述色彩在广告设计中的艺术功能,讨论在广告设计中色彩的配色规律及应用原则。  相似文献   

低碳试点政策对城市碳排放绩效的影响评估及机制分析     

周迪  周丰年  王雪芹 《资源科学》2019,41(3):546-556

低碳试点是实现中国低碳经济发展的一项重要政策,客观评价其实施效果,不仅有利于低碳试点地区更好地推进低碳工作,而且对于低碳试点政策的进一步推广具有重要意义,但低碳试点政策能否实现碳排放绩效的提升尚未得出一致的结论。本文以第二批低碳试点政策为例,基于2012—2016年的地级市面板数据,采用倾向得分匹配—双重差分（PSM-DID）方法研究低碳试点政策对降低城市碳排放强度的影响,以有效降低样本自选择及政策内生性等问题导致的处理效应偏差。研究发现：低碳试点政策对城市的碳排放强度下降具有显著且持续的推动作用;进一步的机制识别结果显示,低碳试点城市主要是通过能源效率的提高以及产业结构升级等方式实现碳强度的下降,且产业升级的效果有逐年增强的趋势,但通过城市绿地碳汇水平的提高而降低碳排放的目标尚未实现。基于此结论,本文认为中国应进一步推广低碳试点政策,积极探索低碳城市的发展模式,特别是提升宜居绿色的城市环境。  相似文献   

Validation of a videogrammetry technique for analysing American football helmet kinematics     

Ann Bailey  James Funk  David Lessley  Chris Sherwood  Jeff Crandall  William Neale 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(5):678-700

ABSTRACT

Professional American football games are recorded in digital video with multiple cameras, often at high resolution and high frame rates. The purpose of this study was to evaluate the accuracy of a videogrammetry technique to calculate translational and rotational helmet velocity before, during and after a helmet impact. In total, 10 football impacts were staged in a National Football League (NFL) stadium by propelling helmeted 50th percentile male crash test dummies into each other or the ground at speeds and orientations representative of concussive impacts for NFL players. The tests were recorded by experienced sports film crews to obtain video coverage and quality typically available for NFL games. A videogrammetry procedure was used to track the position and rotation of the helmet throughout the relevant time interval of the head impact. Compared with rigidly mounted retroreflective marker three dimensional (3-D) motion tracking that was concurrently collected in the experiments, videogrammetry accurately calculated changes in translational and rotational velocity of the helmet using high frame rate (two cameras at 240 Hz) video (7% and 15% error, respectively). Low frame rate (2 cameras at 60 Hz) video was adequate for calculating pre-impact translational velocity but not for calculating the translational or rotational velocity change of the helmet during impact.  相似文献   

Is academic tracking related to gains in learning competence? Using propensity score matching and differential item change functioning analysis for better understanding of tracking implications     

《Learning and Instruction》2020

This study analyzes gains in cognitive components of learning competence with respect to cohorts based on ability tracking in a Czech longitudinal study. Propensity score matching is used to form parallelized samples of academic and non-academic track students and to eliminate the effect of selective school intake. We applied regression models on the total scores to test for the overall track effect. Furthermore, we analyze scores and gains on the subscores and check for differential item functioning in Grade 6 and in change to Grade 9. While after 3 years, no significant difference between the two tracks was apparent in the total learning competence score, we did, however, find significant differences in some subscores and in the functioning of some items. We argue that item-level analysis is important for deeper understanding of the tracking implications and may provide the basis for more precise evidence-based decisions regarding the tracking policy.  相似文献