基于域加权词频法的XML文档级检索实现与评价

利用BM25F模型,通过实验,在INEX 04数据集的基础上,实现了对多个域(元素)词频进行加权的XML文档级检索。XML文档结构的确蕴含了一定的语义信息。利用这些语义信息,可以提高检索性能。表2。图1。参考文献16。     

基于嵌入式技术网络测试仪的研究及设计

本文就网络发展现状进行分析,重点研究了嵌入式技术,C8051F340处理器和TCP/IP协议。提出了一种基于嵌入式技术的网络终端测试仪的设计。     

分析与实践:索尔蒂斯的公共教育哲学观

当前我国教育领域的改革和讨论越来越激烈,而教育研究和实践之间的"沟壑"仍然没有减缓,这种局面如何才能打破,教育专业人士如何参与到公众的讨论中,如何在大众的教育导向中发挥作用,这些都是当前亟待解决的问题.美国学者索尔蒂斯为我们提供了有益的启示.本文从他的"公共教育哲学"观出发,以分析和实践为线索,介绍这一思想形成的背景、基础和图景,寻找其对我国教育发展可能产生的影响.     

无显示屏多功能计算器设计研究

系统采用盛群公司的HT46F49E单片机为主控单元,使用矩阵式键盘和LED阵列作为输入输出设备,应用单片机将输入值或内部值进行运算后把结果输出到对应键盘上的LED灯显示,并以语音的形式读出相应的数字．系统可进行常用的四则运算和查看并以语音读出日历、时间、星期．具有结构新颖、电路简单等优点,避免了传统的显示屏显示参数的弊端,特别适合盲人、老人使用．     

半B-(E,F)-凸规划的性质

研究了半B-(E,F)-凸规划的可行解集、最优解集的基本性质,随后研究了在半B-(E,F)-凸性条件的限制下使得局部最优解成为全局最优解及全局最优解的唯一性,这些结论对于半B-(E,F)-凸规划的最优性条件的研究提供了必要的理论支持。     

化学反应动力学

氟原子加氢分子及其同位素分子的反应(F+H2/D2/HD)在化学反应动力学的研究发展中一直扮演着重要的角色。在过去的10年里,科学家们通过精心设计的实验和高精度的理论计算,使得有关该反应体系的态-态动力学研究,特别是对反应机制、过渡态结构及其动力学性质、非绝热效应的认识有了长足的进步,得到了有关F+H2这个教科书式的反应体系动力学行为的结论性的研究成果。     

2012—2014年F5000农业科学类论文来源及作者的文献计量学分析

【目的】对2012—2014年F5000中农业科学类论文的来源及作者进行文献计量学分析。【方法】筛选2012—2014年入选F5000的农业科学类论文,通过中国知网对其相关信息进行完善,利用EXCEL2007对论文的来源及作者信息进行统计与分析。【结果】共选出829篇论文,来自188家单位,其中中国科学院、中国农业科学院等23家高产单位共产出530篇。该类论文主要发表于少数知名度较高的中国精品科技期刊;北京和江苏产出的论文篇数远大于其他省区。论文的合著率为97.47％,合作度为4.999,20～30岁的硕士、博士作者是其核心作者群体。【结论】明确了2012—2014年F5000中农业科学类论文的来源和作者概况,为农业科技期刊编辑同仁组约高水平研究论文提供了方向。     

The role of ICT knowledge flows for international market share dynamics

This paper investigates the role of Information and Communication Technologies (ICTs) related knowledge flows for international market shares. Using bibliometric data on scientific publications, we analyse the relationship between the strength of 14 OECD countries in four ICT-related scientific fields and the ability of those countries to maintain and acquire export market shares in the OECD market, across 16 manufacturing industries over the period 1981-2003. We find that domestic and foreign ICT-related scientific knowledge flows have a positive and significant impact on export market shares in ICT industries, while only domestic flows positively affect export shares in non-ICT industries. We also find that small open economies benefit more than other countries from foreign knowledge flows both in ICT and in non-ICT industries.     

Intellectual property infringements due to R&D abroad? A comparative analysis between firms with international and domestic innovation activities

This paper aims to analyse the risk of intellectual property (IP) infringements by competitors from abroad and in particular to consider whether this risk is higher for international innovating firms. We distinguish three different types of IP infringements from abroad: the usage of firms’ technical inventions, product piracy, and copying of corporate names and designs. Our analysis rests on the German data from the Europe-wide Community Innovation Survey (CIS). We use a unique data set of about 900 observations, which are retrieved from two survey waves. While the earlier wave contains information about international and domestic innovation activities, the later wave reports IP infringements. In a second analysis, the likelihood of infringements from innovation host countries and no-innovation host countries abroad is examined. Before the empirical analysis, an exploratory study was carried out in China with interviews of German firms with innovation activities in China and with a legal advisor for small and medium-sized German enterprises. The results show that firms with international R&D activities are increasing their chances of losing technological knowledge to their local competitors abroad. R&D activities in countries with weak intellectual property rights increase the risk for all types of IP infringements compared to domestic R&D activities. Infringements by competitors from the host country are driven by the production of new produces in this country. Export intensity is the major driver of infringements from no-innovation host countries. R&D activities in China and North America also increase the risk of an infringement. However, firms that innovate only in their home country experience significantly more product piracy cases than international innovating firms.     

R&D co-operation and innovation a microeconometric study on French firms

The scope of this paper is to report new empirical evidence on the determinants of R&D co-operation. Indeed, the literature on the capabilities of firms emphasises the role of knowledge in the performance and evolution of firms who use knowledge developed in others to build their own knowledge capital. R&D co-operation between firms is one of the many strategies by which this knowledge may be transmitted. Several theoretical models have stressed that R&D co-operation is more likely when the level of spillovers is high. While this supposition is used in many theoretical models, it has rarely been tested before. Our results do not lend strong support to this intuition. Indeed, our spillover variables (national pure spillovers, national rent spillovers and imports of machine tools), which were supposed to match the theoretical notion of spillovers used in these theoretical models have a positive but not a significant role when explaining R&D co-operation. The R&D co-operation increases with size and with R&D intensity, but not with market share. It also increases with the budget spent on paying license fees and on acquiring patents and labour from foreign firms. In this study, we also analyse the determinants of innovation. In more precise terms, we compare the effects of R&D co-operation to those played by traditional internal factors and those exerted by external, pure and rent spillovers on the innovation capacity of the firms. Our results show that the commercial success of innovations of French firms depends mainly on size, market share, R&D intensity and human capital. Inward FDI from industrialised countries exerts a positive and significant effect. The finding highlights the important role of the absorptive capacity of firms. Spillover measurements, such as the acquisition of machine tools, foreign patents, licenses, and technological opportunities have a positive impact on innovation.