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排序方式: 共有336条查询结果,搜索用时 218 毫秒
171.
专利是科学技术的重要知识载体,在技术创新升级和产业跨越式发展中,发挥着不可或缺的作用。利用可视化工具,对专利数据库中云计算技术专利进行分析,研究合作网络及其聚类的知识扩散机制,在云计算专利权人特征描述的基础上,绘制云计算专利共被引、专利发明人以及专利发明机构的知识图谱,形象地反映出云计算领域技术发展态势及其研发主体间的合作关系。结合研究结论,提出了引导我国深入布局云计算产业发展蓝图的对策建议。 相似文献
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t both hybrid decompression and two-level corpectomy could obtain satisfying clinical efficacy in the management of three-level CSM for appropriate patients. 相似文献
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An efficient hybrid evolutionary optimization algorithm based on PSO and SA for clustering 总被引:4,自引:0,他引:4
The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the K- means algorithm depends highly on initial cluster centers and converges to local minima. This paper proposes a hybrid evolutionary programming based clustering algorithm, called PSO-SA, by combining particle swarm optimization (PSO) and simulated annealing (SA). The basic idea is to search around the global solution by SA and to increase the information exchange among particles using a mutation operator to escape local optima. Three datasets, Iris, Wisconsin Breast Cancer, and Ripley's Glass, have been considered to show the effectiveness of the proposed clustering algorithm in providing optimal clusters. The simulation results show that the PSO-SA clustering algorithm not only has a better response but also converges more quickly than the K-means, PSO, and SA algorithms. 相似文献
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Modeling user profiles is a necessary step for most information filtering systems – such as recommender systems – to provide personalized recommendations. However, most of them work with users or items as vectors, by applying different types of mathematical operations between them and neglecting sequential or content-based information. Hence, in this paper we study how to propose an adaptive mechanism to obtain user sequences using different sources of information, allowing the generation of hybrid recommendations as a seamless, transparent technique from the system viewpoint. As a proof of concept, we develop the Longest Common Subsequence (LCS) algorithm as a similarity metric to compare the user sequences, where, in the process of adapting this algorithm to recommendation, we include different parameters to control the efficiency by reducing the information used in the algorithm (preference filter), to decide when a neighbor is considered useful enough to be included in the process (confidence filter), to identify whether two interactions are equivalent (δ-matching threshold), and to normalize the length of the LCS in a bounded interval (normalization functions). These parameters can be extended to work with any type of sequential algorithm.We evaluate our approach with several state-of-the-art recommendation algorithms using different evaluation metrics measuring the accuracy, diversity, and novelty of the recommendations, and analyze the impact of the proposed parameters. We have found that our approach offers a competitive performance, outperforming content, collaborative, and hybrid baselines, and producing positive results when either content- or rating-based information is exploited. 相似文献
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【目的】 比较期刊和会议论文集的影响力差异以及二者的关系,探索期刊与会议论文集的混合共被引分析方法。【方法】 以计算机科学领域为例,从澳大利亚计算研究与教育协会的期刊和会议排名系统中获取A类期刊和会议组成的数据集作为研究对象,基于中国计算机协会的计算机学科分类对期刊和会议名称进行学科标注。从Scopus数据库中抽取出大型混合共被引关系。最后构建期刊-会议混合共被引网络进行共被引分析。【结果】 期刊与会议论文集倾向同类内引用;同一学科聚类不明显;会议论文集在核心共被引网络中具有更强中介中心性,期刊文献在总体共被引网络中具有更强的中介中心性。【结论】 期刊与会议论文集倾向同类内引用;计算机科学领域内各学科融合程度高;高水平会议论文集应纳入部分学科学术评价指标。 相似文献
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国外复合数字对象管理研究撷要 总被引:4,自引:0,他引:4
如何对复合数字对象进行有效的管理和服务,是当前数字图书馆研究中的一个热点前沿话题。文章考察和介绍了国外关于复合数字对象管理的几种典型解决方案,以期对国内这方面的研究和实践提供一些借鉴。 相似文献