基于粗糙集加权的文本分类方法研究   总被引：6，自引：0，他引：6  

胡清华  谢宗霞  于达仁 《情报学报》2005,24(1):59-63

文本自动分类是当前智能信息处理中一类重要的研究课题。本文分析了基于统计理论的文本分类的基本特点,提出采用可变精度粗糙集模型中的分类质量构造新的特征词权重计算公式。这种新的加权方法,相对于广泛使用的逆文本频率加权方法,大大改进了文本样本在整个空间中的分布,使得类内距离减少,类间距离增大,在理论上将提高样本的可分性。最后利用支持向量机和K近邻两种分类器,验证了这种新的加权方法对分类效果确实有所提高。  相似文献   

简评三段式分类索刊号——与施振宏、王觊商稚兼谈刊次号设计     

孙月梅  邓永富 《图书馆建设》2005,(6):61-62,94

针对三段式分类索刊号的编号方法及在实际应用中存在的不足提出商讨意见，并对刊次号的设计提出看法。  相似文献   

Analysis of Statistical Question Classification for Fact-Based Questions   总被引：1，自引：0，他引：1  

Donald Metzler  W. Bruce Croft 《Information Retrieval》2005,8(3):481-504

Question classification systems play an important role in question answering systems and can be used in a wide range of other domains. The goal of question classification is to accurately assign labels to questions based on expected answer type. Most approaches in the past have relied on matching questions against hand-crafted rules. However, rules require laborious effort to create and often suffer from being too specific. Statistical question classification methods overcome these issues by employing machine learning techniques. We empirically show that a statistical approach is robust and achieves good performance on three diverse data sets with little or no hand tuning. Furthermore, we examine the role different syntactic and semantic features have on performance. We find that semantic features tend to increase performance more than purely syntactic features. Finally, we analyze common causes of misclassification error and provide insight into ways they may be overcome.  相似文献   

标志中图像和文字的组合式样及意义表述方式     

茅忠德 《连云港职业技术学院学报》2002,15(4):62-64

标志中图形可以分为图像系统和字系统进行研究，一是确定图像和字之间的建构模式，二是确定图形和字之间谁为主要概念和谁为次要概念，以及主次概念在视觉选择过程中对标志内涵的理解方式。  相似文献   

Granularity of algorithmically constructed publication-level classifications of research publications: Identification of topics     

Peter Sjögårde  Per Ahlgren 《Journal of Informetrics》2018,12(1):133-152

The purpose of this study is to find a theoretically grounded, practically applicable and useful granularity level of an algorithmically constructed publication-level classification of research publications (ACPLC). The level addressed is the level of research topics. The methodology we propose uses synthesis papers and their reference articles to construct a baseline classification. A dataset of about 31 million publications, and their mutual citations relations, is used to obtain several ACPLCs of different granularity. Each ACPLC is compared to the baseline classification and the best performing ACPLC is identified. The results of two case studies show that the topics of the cases are closely associated with different classes of the identified ACPLC, and that these classes tend to treat only one topic. Further, the class size variation is moderate, and only a small proportion of the publications belong to very small classes. For these reasons, we conclude that the proposed methodology is suitable to determine the topic granularity level of an ACPLC and that the ACPLC identified by this methodology is useful for bibliometric analyses.  相似文献   

Four pitfalls in normalizing citation indicators: An investigation of ESI’s selection of highly cited papers     

Zhigang Hu  Wencan Tian  Shenmeng Xu  Chunbo Zhang  Xianwen Wang 《Journal of Informetrics》2018,12(4):1133-1145

InCites Essential Science Indicators is becoming increasingly used to identify top-performing research and evaluate the impact of institutes. Unfortunately, our study shows that ESI indicators, as well as other normalized citation indicators, have the following flaws. First, the publication month and the online-to-print delay affect a paper’s probability of becoming a Highly Cited Paper (HCP). Papers published in the earlier months of the year are more likely to accumulate enough citation counts to rank at the top 1% compared with those published in later months of the year. Papers with longer online-to-print delays have an apparent advantage for being selected as HCPs. Research field normalizations lead to the third pitfall. Different research fields have different citation thresholds for HCPs, making research field classification important for a journal. In addition, the uniform thresholds for both articles and reviews in ESI affect the reliability of HCP selection because, on average, reviews tend to have higher citation rates than articles. ESI’s selection of HCPs provides an intuitive feel for the problems of normalized citation impact indicators, such as those provided in InCites and SciVal.  相似文献   

数字调制类型的识别及实现     

宋全有  李万高 《商丘职业技术学院学报》2006,5(2):59-61

通信信号的调制识别是目前研究的热点问题.本文给出一种新的数字调制信号识别方法.高速数字专用芯片ADSP2101是此方法具体实现的重要器件,这一方法在实际通信中有着广泛的应用.  相似文献   

朱子《大学章句》建构体系的梳理与析出——志与功相统一的说理方法     

宋兵超 《鸡西大学学报》2014,(2):54-55

朱熹在建构《大学章句》的体系时,采取了一种志与功相统一的说理方法。这种方法既表现在《大学》经章里,也表现在《大学》传章里,而且在不同的说理层次上,存在着不同的志与功的统一,既有纲领之间的志与功相统一,也有条目之间的志与功相统一,这分别体现在经章与传章里,而且基本上呈现出一一对应的关系。  相似文献   

Writer identification approach based on bag of words with OBI features     

Amal Durou  Ibrahim Aref  Somaya Al-Maadeed  Ahmed Bouridane  Elhadj Benkhelifa 《Information processing & management》2019,56(2):354-366

Handwriter identification aims to simplify the task of forensic experts by providing them with semi-automated tools in order to enable them to narrow down the search to determine the final identification of an unknown handwritten sample. An identification algorithm aims to produce a list of predicted writers of the unknown handwritten sample ranked in terms of confidence measure metrics for use by the forensic expert will make the final decision.Most existing handwriter identification systems use either statistical or model-based approaches. To further improve the performances this paper proposes to deploy a combination of both approaches using Oriented Basic Image features and the concept of graphemes codebook. To reduce the resulting high dimensionality of the feature vector a Kernel Principal Component Analysis has been used. To gauge the effectiveness of the proposed method a performance analysis, using IAM dataset for English handwriting and ICFHR 2012 dataset for Arabic handwriting, has been carried out. The results obtained achieved an accuracy of 96% thus demonstrating its superiority when compared against similar techniques.  相似文献   

Spontaneous spatial strategy use in learning from scientific text     

《Contemporary educational psychology》2017

Two studies explored the role of the spontaneous use of spatial note-taking strategies (i.e., creating maps and drawings) and spatial ability in learning from a scientific passage. In Study 1, college students read and took notes by hand on a 10-paragraph scientific passage about the human respiratory system. Students tended to use verbal strategies such as lists (on 48% of the paragraphs), outlines (29%) and running text (15%), but also used spatial strategies such as maps (28%) and drawings (11%). Regression analyses indicated that spatial ability and the use of spatial strategies (maps or drawings) significantly predicted learning outcomes, with spatial strategy use explaining additional variance beyond spatial ability. In Study 2, students read the same scientific passage and took notes either by hand on paper (paper group), by hand on a large whiteboard (whiteboard group), or on a laptop computer (computer group). A similar general pattern as Study 1 was found for the paper group, but this pattern was not found for the computer or whiteboard groups, suggesting that the relationships found in Study 1 might depend on the note-taking medium. Results also indicated that students in the paper and whiteboard groups spontaneously used more spatial strategies, whereas the computer group tended to use verbal strategies (i.e., words only), suggesting that different note-taking contexts encourage different strategies.  相似文献