亦秀亦豪 腕挟风雷——从Jesperson的rank、junction、nexus角度赏析张晓风的行文风格

该文首先阐述了Jesperson的rank、junction与nexus的基本内涵。在大量实例分析的基础上,作者指出张晓风散文中修饰首品词的次品词别具一格,妙趣横生。然而可以充分体现张晓风散文非凡艺术创造力的淋漓健笔还在于充满动感、富有气势的nexus结构的大量采用。     

Which percentile-based approach should be preferred for calculating normalized citation impact values? An empirical comparison of five approaches including a newly developed citation-rank approach (P100)

For comparisons of citation impacts across fields and over time, bibliometricians normalize the observed citation counts with reference to an expected citation value. Percentile-based approaches have been proposed as a non-parametric alternative to parametric central-tendency statistics. Percentiles are based on an ordered set of citation counts in a reference set, whereby the fraction of papers at or below the citation counts of a focal paper is used as an indicator for its relative citation impact in the set. In this study, we pursue two related objectives: (1) although different percentile-based approaches have been developed, an approach is hitherto missing that satisfies a number of criteria such as scaling of the percentile ranks from zero (all other papers perform better) to 100 (all other papers perform worse), and solving the problem with tied citation ranks unambiguously. We introduce a new citation-rank approach having these properties, namely P100; (2) we compare the reliability of P100 empirically with other percentile-based approaches, such as the approaches developed by the SCImago group, the Centre for Science and Technology Studies (CWTS), and Thomson Reuters (InCites), using all papers published in 1980 in Thomson Reuters Web of Science (WoS). How accurately can the different approaches predict the long-term citation impact in 2010 (in year 31) using citation impact measured in previous time windows (years 1–30)? The comparison of the approaches shows that the method used by InCites overestimates citation impact (because of using the highest percentile rank when papers are assigned to more than a single subject category) whereas the SCImago indicator shows higher power in predicting the long-term citation impact on the basis of citation rates in early years. Since the results show a disadvantage in this predictive ability for P100 against the other approaches, there is still room for further improvements.     

基于GSP拍卖模型的搜索引擎竞价排名机制研究

在GSP拍卖下单纯竞价模型的基础上进行改进,建立了GSP拍卖下有效竞价排名模型,给出了GSP拍卖下单纯竞价模型中"局部无嫉妒均衡"条件和广告主整体最优竞价策略在有效竞价模型中的等价表述,并证明了有效竞价排名能够使搜索引擎企业和广告主的总体收益实现最优,从而是帕累托有效的,但不能保证搜索引擎企业的收入相对于其他排名方式下的收入也是最高的,除非满足有效竞价排名"搜索引擎最优条件"。     

辽宁省农业气候资源变化特征分析

利用1971年～2000年辽宁地区54个气象站30年气候资料,应用线性气候倾向率方法对年和春、夏、秋、冬四季的光热水等主要农业气候资源要素进行诊断分析,应用Mann-Kendall方法完成了对主要农业气候资源要素的突变性检测。结果表明,近30年来,辽宁省增温趋势明显,热量资源更加丰富,特别是平均最低气温增温幅度尤其显著,冬季增温比春、夏、秋季都显著;气温、积温、无霜期等热量资源在20世纪80年代末期同步发生突变。降水量出现减少的趋势,趋势并不剧烈,但季节性明显,秋季降水减少的贡献最大,与降水有密切关系的蒸发潜力和降水蒸发差的变化趋势并不明显,不存在突变现象。太阳辐射与日照时数变化趋势一致,在1982年发生突变,并一直呈下降趋势,太阳辐射量和日照时数的减少,主要表现为夏季的欠缺。辽宁总体的农业气候变化存在以“气温显著升高,降水、日照减少”为主要特点的暖干化趋势,这种趋势在秋季表现得更为明显一些。最后简要讨论了农业气候资源的变化给辽宁农业生产带来的主要影响问题。     

表/数据库文件中名次数据的自动添加

本文针对FOX系列中用SORT命令不能给表 /数据库文件自动地填上名次字段这一问题 ,较为巧妙地使用两种实现方法解决了这一问题 ,具有较强的实践性和可参考性     

搜索力经济研究

目前,由搜索引擎所引领的另类网络虚拟经济形态一“搜索力经济”正在迅速崛起。作为互联网新经济的核心价值,搜索力正引领着互联网的现在和未来。本文将对这一“热点区域”对“搜索力经济”的概念、出现原因及引发的变革等相关问题进行分析,帮助读者对互联网的新领域有更深刻的了解。     

学术文本词汇功能识别——在关键词自动抽取中的应用

传统的关键词自动抽取常以候选词的出现频次、位置等非语义信息构建特征,并未考虑关键词在学术文献中承担的特定语义角色,即词汇功能。通过对现有数据统计,本文发现作者标注关键词中约有67.99%是研究问题或研究方法词。因此,本文将关键词的词汇功能分为三类:"研究问题""研究方法"和"其他",在传统的词频特征以及位置特征基础上,融合词汇功能特征,使用计算机领域的学术文献基于分类和排序两种思想进行关键词抽取实验。实验结果表明,融合词汇功能后,关键词抽取效果得到明显提升。相较于基准实验,二分类模型的准确率Acc和F值分别相对提升24.63%和25.19%,达到了0.840和0.666;排序模型的MAP、NDCG@5和P@5分别相对提升168.32%、189.50%和148.30%,提升至0.813、0.828和0.447,证明了学术文献词汇功能特征在关键词自动抽取中具有重要作用。     

Comparison of Chinese Gaokao and Western university undergraduate admission criteria: Australian ATAR as an example

ABSTRACT

This is the first study that examines the comparative validity of the Chinese National College Entrance Exam (known as Gaokao) to a Western end-of-secondary-school performance measure, Australian Tertiary Admission Rank (ATAR), as admission criteria to an Australian undergraduate degree programme. The study offers a strong warning about using just an aggregate Gaokao score as a sole admission criterion. However, the findings suggest that with adjustments for gender and time, Gaokao is found to be as good an admission criterion as ATAR, hence justifying its use for selection purposes if such adjustments are made. Supplementing selection criteria by also using the Gaokao English result is found to be a further improvement. The findings can help inform the admission policy relevant to Chinese international students into undergraduate degree programmes globally.     

Comparing Numerical Methods to Estimate Vertical Jump Height Using a Force Platform

ABSTRACT

Males (n = 29) and females (n = 34) performed vertical jumps. Jump height was estimated from force platform data using five numerical methods and compared using intraclass correlation (ρ), and linear and rank regression standard error of estimate (SEE). Take-off velocity plus center of mass height at take-off and mechanical work methods were identical (ρ = 1.000) with small linear (SEE < 0.0001 cm) and rank order (SEE = 0) error. Integrating acceleration to displacement was nearly identical (ρ > 0.999), with small linear (SEE = 0.1 cm) and rank order (SEE < 1) errors compared to the above methods. Take-off velocity (ρ = 0.517) and flight time (ρ = 0.573) estimates were less than all other methods and had large linear (SEE ≥ 2.1 cm) and rank order (SEE > 4) errors. Take-off velocity and flight time methods should be avoided due to systematic and random error.     

关于欧氏环Ⅰ上的线性方程组的解的确定

本文给出了欧氏环I上的线性方程组的解的判定条件及有关解法.