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排序方式: 共有1716条查询结果,搜索用时 15 毫秒
1.
Alain R. Lamothe 《International Information and Library Review》2020,52(2):139-160
AbstractThis article reports the results of a quantitative and systematic analysis comparing usage rates between English-language and French-language e-monograph titles at Laurentian University, Canada. Full-text viewings were collected as usage metrics. English-language e-monographs exhibited medium strength linear relationships between collection size and usage. On the other hand, French-language e-monographs exhibited weak linear relationships between collection size and usage. The French-language e-monograph collection experienced a higher rate of full-text use, relative to size. The cost-per-viewing ratio for the English-language e-monograph collection was higher than those that calculated for the French-language collection. 相似文献
2.
上海市技术比较优势及其演变分析——基于上海市职务发明专利申请的统计分析 总被引:1,自引:0,他引:1
上海市是我国发明专利申请最活跃和技术创新能力最强的城市之一,充分发挥其技术比较优势,不仅有利于其进一步提升技术创新能力,而且也有利于其代表我国在全球科技竞争中占据制高点。本文在对上海职务发明专利申请进行分技术领域统计的基础上,首先对上海职务发明专利申请态势、技术领域分布及其在全国中的地位进行了分析,其次根据其不同技术领域的显性技术比较优势指数,对其技术比较优势及演变进行了研究,最后对上述分析结果的公共政策含义进行了初步探讨。 相似文献
3.
Ivan Bradaric Athina P. Petropulu Konstantinos I. Diamantaras 《Journal of The Franklin Institute》2002,339(2):161-187
Higher-order statistics (HOS) are well known for their robustness to additive Gaussian noise and ability to preserve phase. HOS estimates, on the other hand, have been criticized for high complexity and the need for long data in order to maintain small variance. Since rank reduction offers a general principle for reduction of estimator variance and complexity, we consider the problem of designing low-rank estimators for HOS. We propose three methods for choosing the transformation matrix that reduces the mean-square error (MSE) associated with the low-rank HOS estimates. We also demonstrate the advantages of using low-rank third-order moment estimates for blind system estimation. Results indicate that the full rank MSE corresponding to some data length N can be attained by a low-rank estimator corresponding to a length significantly smaller than N. 相似文献
4.
本文通过对1994~2003年我国情报学研究论文作者及其地区分布、系统分布、合著情况、高产作者、高产单位等进行分析,以揭示我国情报学研究队伍的现状,为我国情报学研究提供某一角度的数据参考。 相似文献
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着重指出了管理统计在企业管理中应用的重要性,并对企业管理的发展进行了探讨,同时,结合企业管理的实际情况,阐述了管理统计在企业管理中运用的思路。 相似文献
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David Nicholas Paul Huntington Hamid R. Jamali Anthony Watkinson 《Information processing & management》2006
The article employs deep log analysis (DLA) techniques, a more sophisticated form of transaction log analysis, to demonstrate what usage data can disclose about information seeking behaviour of virtual scholars – academics, and researchers. DLA works with the raw server log data, not the processed, pre-defined and selective data provided by journal publishers. It can generate types of analysis that are not generally available via proprietary web logging software because the software filters out relevant data and makes unhelpful assumptions about the meaning of the data. DLA also enables usage data to be associated with search/navigational and/or user demographic data, hence the name ‘deep’. In this connection the usage of two digital journal libraries, those of EmeraldInsight, and Blackwell Synergy are investigated. The information seeking behaviour of nearly three million users is analyzed in respect to the extent to which they penetrate the site, the number of visits made, as well as the type of items and content they view. The users are broken down by occupation, place of work, type of subscriber (“Big Deal”, non-subscriber, etc.), geographical location, type of university (old and new), referrer link used, and number of items viewed in a session. 相似文献
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Dexin Shi Christine DiStefano Heather L. McDaniel Zhehan Jiang 《Structural equation modeling》2018,25(6):924-945
This study examined the effect of model size on the chi-square test statistics obtained from ordinal factor analysis models. The performance of six robust chi-square test statistics were compared across various conditions, including number of observed variables (p), number of factors, sample size, model (mis)specification, number of categories, and threshold distribution. Results showed that the unweighted least squares (ULS) robust chi-square statistics generally outperform the diagonally weighted least squares (DWLS) robust chi-square statistics. The ULSM estimator performed the best overall. However, when fitting ordinal factor analysis models with a large number of observed variables and small sample size, the ULSM-based chi-square tests may yield empirical variances that are noticeably larger than the theoretical values and inflated Type I error rates. On the other hand, when the number of observed variables is very large, the mean- and variance-corrected chi-square test statistics (e.g., based on ULSMV and WLSMV) could produce empirical variances conspicuously smaller than the theoretical values and Type I error rates lower than the nominal level, and demonstrate lower power rates to reject misspecified models. Recommendations for applied researchers and future empirical studies involving large models are provided. 相似文献