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排序方式： 共有180条查询结果，搜索用时 15 毫秒
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73.
Knowledge coherence, variety and economic growth: Manufacturing evidence from Italian regions 总被引：2，自引：0，他引：2
Francesco Quatraro 《Research Policy》2010,39(10):1289-1302
This paper elaborates a view on knowledge as a result of a combinatorial search activity, so as to investigate its effects on economic growth at the regional level. Empirical estimations corroborate the hypothesis that knowledge coherence and variety, besides the traditional measure of knowledge stock, matter in shaping regional economic performances. The check for spatial dependence suggests that cross-regional externalities exert additional triggering effects on growth, without debasing the effects of knowledge properties. Important policy implications stem from the analysis, in that regional innovation strategies should be carefully coordinated so as to reach a higher degree of internal coherence and trigger economic performances. 相似文献
74.
The launch of Google Scholar Metrics as a tool for assessing scientific journals may be serious competition for Thomson Reuters' Journal Citation Reports, and for the Scopus‐powered Scimago Journal Rank. A review of these bibliometric journal evaluation products is performed. We compare their main characteristics from different approaches: coverage, indexing policies, search and visualization, bibliometric indicators, results analysis options, economic cost, and differences in their ranking of journals. Despite its shortcomings, Google Scholar Metrics is a helpful tool for authors and editors in identifying core journals. As an increasingly useful tool for ranking scientific journals, it may also challenge established journals products. 相似文献
75.
ABSTRACTEducation is the main vehicle for empowering adults, and can contribute to community wellbeing. However, regarding mature adults (MAs) (over 45 years old), age has been identified in various studies as a significant barrier to accessing educational activities. This paper focuses on MAs’ motivations to learn through an exploratory survey undertaken in six European countries. A K-means cluster analysis based on 16 variables has been run on n = 846 valid cases. Four clusters describing distinctive behaviours and attitudes of MAs towards learning activities were identified. The study confirms that MAs’ motivations to learn are very diverse, overcoming some of the so-called myths of global aging, such as the homogeneity of MAs or the correlation between age and a decline in motivation to learn. Furthermore, analysing the main motivations of MA learners can be useful for adapting education to cater to their specific needs, boosting a more inclusive education, and promoting MAs’ empowerment. 相似文献
76.
Query reformulation mining: models,patterns, and applications 总被引：1，自引：0，他引：1
Paolo Boldi Francesco Bonchi Carlos Castillo Sebastiano Vigna 《Information Retrieval》2011,14(3):257-289
Understanding query reformulation patterns is a key task towards next generation web search engines. If we can do that, then
we can build systems able to understand and possibly predict user intent, providing the needed assistance at the right time,
and thus helping users locate information more effectively and improving their web-search experience. As a step in this direction,
we build a very accurate model for classifying user query reformulations into broad classes (generalization, specialization,
error correction or parallel move), achieving 92% accuracy. We then apply the model to automatically label two very large
query logs sampled from different geographic areas, and containing a total of approximately 17 million query reformulations.
We study the resulting reformulation patterns, matching some results from previous studies performed on smaller manually annotated
datasets, and discovering new interesting reformulation patterns, including connections between reformulation types and topical
categories. We annotate two large query-flow graphs with reformulation type information, and run several graph-characterization
experiments on these graphs, extracting new insights about the relationships between the different query reformulation types.
Finally we study query recommendations based on short random walks on the query-flow graphs. Our experiments show that these
methods can match in precision, and often improve, recommendations based on query-click graphs, without the need of users’
clicks. Our experiments also show that it is important to consider transition-type labels on edges for having recommendations
of good quality. 相似文献
77.
A historical case study concerning the serious doubts that arose in early 1930s about the validity of the law of energy conservation in nuclear disintegrations, and the hypothesis of neutrino, will be closely analyzed with the goal of promoting understanding of the nature of science. This work is based upon primary archival and printed sources, with a particular focus on the proceedings of the first International Conference of Nuclear Physics which was held in Rome on October 1931. 相似文献
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