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Text Extraction and Enhancement of Binary Images Using Cellular Automata
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作者 G. Sahoo Tapas Kumar +1 位作者 B. L. Raina C. M. Bhatia 《International Journal of Automation and computing》 EI 2009年第3期254-260,共7页
Text characters embedded in images represent a rich source of information for content-based indexing and retrieval applications. However, these text characters are difficult to be detected and recognized due to their ... Text characters embedded in images represent a rich source of information for content-based indexing and retrieval applications. However, these text characters are difficult to be detected and recognized due to their various sizes, grayscale values, and complex backgrounds. Existing methods cannot handle well those texts with different contrast or embedded in a complex image background. In this paper, a set of sequential algorithms for text extraction and enhancement of image using cellular automata are proposed. The image enhancement includes gray level, contrast manipulation, edge detection, and filtering. First, it applies edge detection and uses a threshold to filter out for low-contrast text and simplify complex background of high-contrast text from binary image. The proposed algorithm is simple and easy to use and requires only a sample texture binary image as an input. It generates textures with perceived quality, better than those proposed by earlier published techniques. The performance of our method is demonstrated by presenting experimental results for a set of text based binary images. The quality of thresholding is assessed using the precision and recall analysis of the resultant text in the binary image. 展开更多
关键词 text extraction edge detection cellular automata algorithm text detection thresholding.
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An Efficient HW/SW Design for Text Extraction from Complex Color Image
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作者 Mohamed Amin Ben Atitallah Rostom Kachouri +1 位作者 Ahmed Ben Atitallah Hassene Mnif 《Computers, Materials & Continua》 SCIE EI 2022年第6期5963-5977,共15页
In the context of constructing an embedded system to help visually impaired people to interpret text,in this paper,an efficient High-level synthesis(HLS)Hardware/Software(HW/SW)design for text extraction using the Gam... In the context of constructing an embedded system to help visually impaired people to interpret text,in this paper,an efficient High-level synthesis(HLS)Hardware/Software(HW/SW)design for text extraction using the Gamma Correction Method(GCM)is proposed.Indeed,the GCM is a common method used to extract text from a complex color image and video.The purpose of this work is to study the complexity of the GCM method on Xilinx ZCU102 FPGA board and to propose a HW implementation as Intellectual Property(IP)block of the critical blocks in this method using HLS flow with taking account the quality of the text extraction.This IP is integrated and connected to the ARM Cortex-A53 as coprocessor in HW/SW codesign context.The experimental results show that theHLS HW/SW implementation of the GCM method on ZCU102 FPGA board allows a reduction in processing time by about 89%compared to the SW implementation.This result is given for the same potency and strength of SW implementation for the text extraction. 展开更多
关键词 text extraction GCM HW/SW codesign FPGA HLS flow
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Efficient Text Extraction Algorithm Using Color Clustering for Language Translation in Mobile Phone 被引量:2
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作者 Adrián Canedo-Rodríguez Jung Hyoun Kim +5 位作者 Soo-Hyung Kim John Kelly Jung Hee Kim Sun Yi Sai Kiran Veeramachaneni Yolanda Blanco-Fernández 《Journal of Signal and Information Processing》 2012年第2期228-237,共10页
Many Text Extraction methodologies have been proposed, but none of them are suitable to be part of a real system implemented on a device with low computational resources, either because their accuracy is insufficient,... Many Text Extraction methodologies have been proposed, but none of them are suitable to be part of a real system implemented on a device with low computational resources, either because their accuracy is insufficient, or because their performance is too slow. In this sense, we propose a Text Extraction algorithm for the context of language translation of scene text images with mobile phones, which is fast and accurate at the same time. The algorithm uses very efficient computations to calculate the Principal Color Components of a previously quantized image, and decides which ones are the main foreground-background colors, after which it extracts the text in the image. We have compared our algorithm with other algorithms using commercial OCR, achieving accuracy rates more than 12% higher, and performing two times faster. Also, our methodology is more robust against common degradations, such as uneven illumination, or blurring. Thus, we developed a very attractive system to accurately separate foreground and background from scene text images, working over low computational resources devices. 展开更多
关键词 text extraction COLOR QUANTIZATION text BINARIZATION LANGUAGE TRANSLATION
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A New Method to Extract Text from Natural Scenes
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作者 郝峻晟 戚飞虎 +1 位作者 朱凯华 蒋人杰 《Journal of Donghua University(English Edition)》 EI CAS 2005年第4期52-57,共6页
This paper presents a new method for text detection, location and binarization from natural scenes. Several morphological steps are used to detect the general position of the text, including English, Chinese and Japan... This paper presents a new method for text detection, location and binarization from natural scenes. Several morphological steps are used to detect the general position of the text, including English, Chinese and Japanese characters. Next bonnding boxes are processed by a new “Expand, Break and Merge” (EBM) method to get the precise text areas. Finally, text is binarized by a hybrid method based on Otsu and Niblack. This new approach can extract different kinds of text from complicated natural scenes. It is insensitive to noise, distortedness, and text orientation. It also has good performance on extracting texts in various sizes. 展开更多
关键词 text extraction mathematical morphology bounding boxes binarization
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基于改进TextRank的科技文本关键词抽取方法 被引量:1
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作者 杨冬菊 胡成富 《计算机应用》 CSCD 北大核心 2024年第6期1720-1726,共7页
针对科技文本关键词抽取任务中抽取出现次数少但能较好表达文本主旨的词语效果差的问题,提出一种基于改进TextRank的关键词抽取方法。首先,利用词语的词频-逆文档频率(TF-IDF)统计特征和位置特征优化共现图中词语间的概率转移矩阵,通过... 针对科技文本关键词抽取任务中抽取出现次数少但能较好表达文本主旨的词语效果差的问题,提出一种基于改进TextRank的关键词抽取方法。首先,利用词语的词频-逆文档频率(TF-IDF)统计特征和位置特征优化共现图中词语间的概率转移矩阵,通过迭代计算得到词语的初始得分;然后,利用K-Core(K-Core decomposition)算法挖掘KCore子图得到词语的层级特征,利用平均信息熵特征衡量词语的主题表征能力;最后,在词语初始得分的基础上融合层级特征和平均信息熵特征,从而确定关键词。实验结果表明,在公开数据集上,与TextRank方法和OTextRank(Optimized TextRank)方法相比,所提方法在抽取不同关键词数量的实验中,F1均值分别提高了6.5和3.3个百分点;在科技服务项目数据集上,与TextRank方法和OTextRank方法相比,所提方法在抽取不同关键词数量的实验中,F1均值分别提高了7.4和3.2个百分点。实验结果验证了所提方法抽取出现频率低但较好表达文本主旨关键词的有效性。 展开更多
关键词 科技文本 关键词抽取 textRank K-Core图 平均信息熵
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Smart Approaches to Efficient Text Mining for Categorizing Sexual Reproductive Health Short Messages into Key Themes
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作者 Tobias Makai Mayumbo Nyirenda 《Open Journal of Applied Sciences》 2024年第2期511-532,共22页
To promote behavioral change among adolescents in Zambia, the National HIV/AIDS/STI/TB Council, in collaboration with UNICEF, developed the Zambia U-Report platform. This platform provides young people with improved a... To promote behavioral change among adolescents in Zambia, the National HIV/AIDS/STI/TB Council, in collaboration with UNICEF, developed the Zambia U-Report platform. This platform provides young people with improved access to information on various Sexual Reproductive Health topics through Short Messaging Service (SMS) messages. Over the years, the platform has accumulated millions of incoming and outgoing messages, which need to be categorized into key thematic areas for better tracking of sexual reproductive health knowledge gaps among young people. The current manual categorization process of these text messages is inefficient and time-consuming and this study aims to automate the process for improved analysis using text-mining techniques. Firstly, the study investigates the current text message categorization process and identifies a list of categories adopted by counselors over time which are then used to build and train a categorization model. Secondly, the study presents a proof of concept tool that automates the categorization of U-report messages into key thematic areas using the developed categorization model. Finally, it compares the performance and effectiveness of the developed proof of concept tool against the manual system. The study used a dataset comprising 206,625 text messages. The current process would take roughly 2.82 years to categorise this dataset whereas the trained SVM model would require only 6.4 minutes while achieving an accuracy of 70.4% demonstrating that the automated method is significantly faster, more scalable, and consistent when compared to the current manual categorization. These advantages make the SVM model a more efficient and effective tool for categorizing large unstructured text datasets. These results and the proof-of-concept tool developed demonstrate the potential for enhancing the efficiency and accuracy of message categorization on the Zambia U-report platform and other similar text messages-based platforms. 展开更多
关键词 Knowledge Discovery in text (KDT) Sexual Reproductive Health (SRH) text Categorization text Classification text extraction text Mining Feature extraction Automated Classification Process Performance Stemming and Lemmatization Natural Language Processing (NLP)
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Text extraction method for historical Tibetan document images based on block projections 被引量:3
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作者 段立娟 张西群 +1 位作者 马龙龙 吴健 《Optoelectronics Letters》 EI 2017年第6期457-461,共5页
Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of te... Text extraction is an important initial step in digitizing the historical documents. In this paper, we present a text extraction method for historical Tibetan document images based on block projections. The task of text extraction is considered as text area detection and location problem. The images are divided equally into blocks and the blocks are filtered by the information of the categories of connected components and corner point density. By analyzing the filtered blocks' projections, the approximate text areas can be located, and the text regions are extracted. Experiments on the dataset of historical Tibetan documents demonstrate the effectiveness of the proposed method. 展开更多
关键词 HISTORICAL TIBETAN document filtered BLOCKS bounding CORNER APPROXIMATE projection COORDINATE
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A Hybrid Method of Extractive Text Summarization Based on Deep Learning and Graph Ranking Algorithms 被引量:1
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作者 SHI Hui WANG Tiexin 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2022年第S01期158-165,共8页
In the era of Big Data,we are faced with an inevitable and challenging problem of“overload information”.To alleviate this problem,it is important to use effective automatic text summarization techniques to obtain th... In the era of Big Data,we are faced with an inevitable and challenging problem of“overload information”.To alleviate this problem,it is important to use effective automatic text summarization techniques to obtain the key information quickly and efficiently from the huge amount of text.In this paper,we propose a hybrid method of extractive text summarization based on deep learning and graph ranking algorithms(ETSDG).In this method,a pre-trained deep learning model is designed to yield useful sentence embeddings.Given the association between sentences in raw documents,a traditional LexRank algorithm with fine-tuning is adopted fin ETSDG.In order to improve the performance of the extractive text summarization method,we further integrate the traditional LexRank algorithm with deep learning.Testing results on the data set DUC2004 show that ETSDG has better performance in ROUGE metrics compared with certain benchmark methods. 展开更多
关键词 extractive text summarization deep learning sentence embeddings LexRank
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A Method of Text Extremum Region Extraction Based on Joint-Channels 被引量:1
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作者 Xueming Qiao Weiyi Zhu +4 位作者 Dongjie Zhu Liang Kong Yingxue Xia Chunxu Lin Zhenhao Guo Yiheng Sun 《Journal on Artificial Intelligence》 2020年第1期29-37,共9页
Natural scene recognition has important significance and value in the fields of image retrieval,autonomous navigation,human-computer interaction and industrial automation.Firstly,the natural scene image non-text conte... Natural scene recognition has important significance and value in the fields of image retrieval,autonomous navigation,human-computer interaction and industrial automation.Firstly,the natural scene image non-text content takes up relatively high proportion;secondly,the natural scene images have a cluttered background and complex lighting conditions,angle,font and color.Therefore,how to extract text extreme regions efficiently from complex and varied natural scene images plays an important role in natural scene image text recognition.In this paper,a Text extremum region Extraction algorithm based on Joint-Channels(TEJC)is proposed.On the one hand,it can solve the problem that the maximum stable extremum region(MSER)algorithm is only suitable for gray images and difficult to process color images.On the other hand,it solves the problem that the MSER algorithm has high complexity and low accuracy when extracting the most stable extreme region.In this paper,the proposed algorithm is tested and evaluated on the ICDAR data set.The experimental results show that the method has superiority. 展开更多
关键词 Feature extraction scene text detection scene text feature extraction extreme region
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A Deep Look into Extractive Text Summarization
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作者 Jhonathan Quillo-Espino Rosa María Romero-González Ana-Marcela Herrera-Navarro 《Journal of Computer and Communications》 2021年第6期24-37,共14页
This investigation has presented an approach to Extractive Automatic Text Summarization (EATS). A framework focused on the summary of a single document has been developed, using the Tf-ldf method (Frequency Term, Inve... This investigation has presented an approach to Extractive Automatic Text Summarization (EATS). A framework focused on the summary of a single document has been developed, using the Tf-ldf method (Frequency Term, Inverse Document Frequency) as a reference, dividing the document into a subset of documents and generating value of each of the words contained in each document, those documents that show Tf-Idf equal or higher than the threshold are those that represent greater importance, therefore;can be weighted and generate a text summary according to the user’s request. This document represents a derived model of text mining application in today’s world. We demonstrate the way of performing the summarization. Random values were used to check its performance. The experimented results show a satisfactory and understandable summary and summaries were found to be able to run efficiently and quickly, showing which are the most important text sentences according to the threshold selected by the user. 展开更多
关键词 text Mining Preprocesses text Summarization extractive text Sumarization
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基于BiGRU TextCNN框架的漏洞自动分类技术研究
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作者 张浩 何东昊 《信息安全研究》 CSCD 北大核心 2024年第5期446-452,共7页
通用缺陷枚举(CVE)信息可以用于记录已知漏洞并提供标准化的语义描述,利用CWE信息对漏洞进行分类,可以为漏洞挖掘提供更丰富的背景知识和更详细的预防措施.但由于人工分类的不确定性和漏洞本身信息参数的变化,在具体实践中漏洞分类的准... 通用缺陷枚举(CVE)信息可以用于记录已知漏洞并提供标准化的语义描述,利用CWE信息对漏洞进行分类,可以为漏洞挖掘提供更丰富的背景知识和更详细的预防措施.但由于人工分类的不确定性和漏洞本身信息参数的变化,在具体实践中漏洞分类的准确性亟待提高,此外大量且不断增加的新漏洞对人工分类的效率和准确性也提出了巨大挑战.为解决这一问题,提出了一个基于BiGRU TextCNN模型的漏洞分类方法,可用于对漏洞信息的处理、训练和预测,并根据漏洞自身所表征的描述信息自动进行分类.为验证所提方法的适用性和可行性,首先对不同分类模型进行对比分析,然后利用所提出的框架模型通过对漏洞所表征的描述信息进行预测分类,结果证明了所提方法的正确性. 展开更多
关键词 漏洞分类 文本分类 条件抽取 深度学习 安全告警
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Performance Analysis of Optimized Content Extraction for Cyrillic Mongolian Learning Text Materials in the Database
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作者 Bat-Erdene Nyandag Ru Li G. Indruska 《Journal of Computer and Communications》 2016年第10期79-89,共12页
This paper had developed and tested optimized content extraction algorithm using NLP method, TFIDF method for word of weight, VSM for information search, cosine method for similar quality calculation from learning doc... This paper had developed and tested optimized content extraction algorithm using NLP method, TFIDF method for word of weight, VSM for information search, cosine method for similar quality calculation from learning document at the distance learning system database. This test covered following things: 1) to parse word structure at the distance learning system database documents and Cyrillic Mongolian language documents at the section, to form new documents by algorithm for identifying word stem;2) to test optimized content extraction from text material based on e-test results (key word, correct answer, base form with affix and new form formed by word stem without affix) at distance learning system, also to search key word by automatically selecting using word extraction algorithm;3) to test Boolean and probabilistic retrieval method through extended vector space retrieval method. This chapter covers: to process document content extraction retrieval algorithm, to propose recommendations query through word stem, not depending on word position based on Cyrillic Mongolian language documents distinction. 展开更多
关键词 Cyrillic Mongolian Language Content extraction Formatting Learning text Materials Style
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Mathematical Expression Extraction in Text Fields of Documents Based on HMM
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作者 Xuedong Tian Ruihan Bai +2 位作者 Fang Yang Jinyuan Bai Xinfu Li 《Journal of Computer and Communications》 2017年第14期1-13,共13页
Aiming at the problem that the mathematical expressions in unstructured text fields of documents are hard to be extracted automatically, rapidly and effectively, a method based on Hidden Markov Model (HMM) is proposed... Aiming at the problem that the mathematical expressions in unstructured text fields of documents are hard to be extracted automatically, rapidly and effectively, a method based on Hidden Markov Model (HMM) is proposed. Firstly, this method trained the HMM model through employing the symbol combination features of mathematical expressions. Then, some preprocessing works such as removing labels and filtering words were carried out. Finally, the preprocessed text was converted into an observation sequence as the input of the HMM model to determine which is the mathematical expression and extracts it. The experimental results show that the proposed method can effectively extract the mathematical expressions from the text fields of documents, and also has the relatively high accuracy rate and recall rate. 展开更多
关键词 Mathematical Expression extractION Hidden MARKOV Model text FIELDS DOCUMENTS SYMBOL Combination Features
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基于改进的TextRank的自动摘要提取方法 被引量:41
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作者 余珊珊 苏锦钿 李鹏飞 《计算机科学》 CSCD 北大核心 2016年第6期240-247,共8页
经典的TextRank算法在文档的自动摘要提取时往往只考虑了句子节点间的相似性,而忽略了文档的篇章结构及句子的上下文信息。针对这些问题,结合中文文本的结构特点,提出一种改进后的iTextRank算法,通过将标题、段落、特殊句子、句子位置... 经典的TextRank算法在文档的自动摘要提取时往往只考虑了句子节点间的相似性,而忽略了文档的篇章结构及句子的上下文信息。针对这些问题,结合中文文本的结构特点,提出一种改进后的iTextRank算法,通过将标题、段落、特殊句子、句子位置和长度等信息引入到TextRank网络图的构造中,给出改进后的句子相似度计算方法及权重调整因子,并将其应用于中文文本的自动摘要提取,同时分析了算法的时间复杂度。最后,实验证明iTextRank比经典的TextRank方法具有更高的准确率和更低的召回率。 展开更多
关键词 中文文本 自动摘要提取 textRank 篇章结构 无监督学习方法
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一种基于TextRank的文本二次聚类算法 被引量:3
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作者 潘晓英 胡开开 朱静 《计算机技术与发展》 2016年第8期7-11,共5页
针对传统文本聚类技术中存在的聚类精度一般或者运算时间复杂度过高等问题,文中首先介绍了两种较为常用的文本聚类技术:基于划分的K-means和基于主题模型的LDA。在分析各自缺陷的基础上,提出一种基于TextRank的文本二次聚类算法。该算... 针对传统文本聚类技术中存在的聚类精度一般或者运算时间复杂度过高等问题,文中首先介绍了两种较为常用的文本聚类技术:基于划分的K-means和基于主题模型的LDA。在分析各自缺陷的基础上,提出一种基于TextRank的文本二次聚类算法。该算法借鉴主题模型的思想,在传统的聚类过程中引入词聚类,并在关键词提取阶段融合词语的位置与跨度特征,减少了由局部关键词作为全局关键词带来的误差。实验结果表明,改进后的算法在聚类效果上要优于传统的VSM聚类和基于主题模型的LDA算法。 展开更多
关键词 文本聚类 textRank 关键词提取 向量空间模型 LDA
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融合多特征的TextRank藏文文本关键词抽取方法研究 被引量:4
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作者 艾金勇 《情报探索》 2020年第7期1-6,共6页
[目的/意义]旨在为提升藏文文本关键词的抽取效果提供参考。[方法/过程]分析中英文文本关键词抽取方法的特点和存在问题,针对藏文文本特点,提出一种融合多特征的TextRank关键词抽取方法,通过实验获取不同特征的相对最优权重系数,并将权... [目的/意义]旨在为提升藏文文本关键词的抽取效果提供参考。[方法/过程]分析中英文文本关键词抽取方法的特点和存在问题,针对藏文文本特点,提出一种融合多特征的TextRank关键词抽取方法,通过实验获取不同特征的相对最优权重系数,并将权值计算公式应用于TextRank的初始权值与转移概率的计算中。[结果/结论]该方法通过融合藏文文本的结构特征以及词语之间语法关系等关键词提取影响因素,实现了候选关键词的量化权值,相比于传统方法关键词抽取效果有明显提升,同时证明融合结构特征与语法特征能有效改善TextRank算法的性能。 展开更多
关键词 多特征 textRank 藏文文本 关键词抽取
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一种基于TextRank的单文本关键字提取算法 被引量:20
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作者 柳林青 余瀚 +1 位作者 费宁 陈春玲 《计算机应用研究》 CSCD 北大核心 2018年第3期705-710,共6页
作为一种经典的文本关键字提取和摘要自动生成算法,TextRank将文本看做若干单词组成的集合,并通过对单词节点图的节点权值进行迭代计算,挖掘单词之间的潜在语义关系。在TextRank节点图模型的基础上,将马尔可夫状态转移模型与节点图相结... 作为一种经典的文本关键字提取和摘要自动生成算法,TextRank将文本看做若干单词组成的集合,并通过对单词节点图的节点权值进行迭代计算,挖掘单词之间的潜在语义关系。在TextRank节点图模型的基础上,将马尔可夫状态转移模型与节点图相结合,提出节点间边权为条件概率的新模型生成算法TextRank_Revised。通过对有标记和无标记的验证集进行验证,证明新的算法在不提升时间复杂度的前提下,通过计算单文本得出的单词排序结果相较于原TextRank算法更加吻合人工对文档的关键字提取结果。 展开更多
关键词 textRank 单文本关键字 提取算法 有向带权图 马尔可夫状态转移模型
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基于TextRank算法和互信息相似度的维吾尔文关键词提取及文本分类 被引量:8
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作者 阿力甫.阿不都克里木 李晓 《计算机科学》 CSCD 北大核心 2016年第12期36-40,共5页
针对维吾尔语文本的分类问题,提出一种基于TextRank算法和互信息相似度的维吾尔文关键词提取及文本分类方法。首先,对输入文本进行预处理,滤除非维吾尔语的字符和停用词;然后,利用词语语义相似度、词语位置和词频重要性加权的TextRank... 针对维吾尔语文本的分类问题,提出一种基于TextRank算法和互信息相似度的维吾尔文关键词提取及文本分类方法。首先,对输入文本进行预处理,滤除非维吾尔语的字符和停用词;然后,利用词语语义相似度、词语位置和词频重要性加权的TextRank算法提取文本关键词集合;最后,根据互信息相似度度量,计算输入文本关键词集和各类关键词集的相似度,最终实现文本的分类。实验结果表明,该方案能够提取出具有较高识别度的关键词,当关键词集大小为1250时,平均分类率达到了91.2%。 展开更多
关键词 维吾尔语 文本分类 关键词提取 textRank算法 互信息相似度
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融合TextRank算法的中文短文本相似度计算 被引量:5
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作者 卢佳伟 陈玮 尹钟 《电子科技》 2020年第10期51-56,共6页
传统的VSM向量空间模型忽略了文本语义,构建的文本特征矩阵具有稀疏性。基于深度学习词向量技术,文中提出一种融合改进TextRank算法的相似度计算方法。该方法利用词向量嵌入的技术来构建文本向量空间,使得构建的向量空间模型具有了语义... 传统的VSM向量空间模型忽略了文本语义,构建的文本特征矩阵具有稀疏性。基于深度学习词向量技术,文中提出一种融合改进TextRank算法的相似度计算方法。该方法利用词向量嵌入的技术来构建文本向量空间,使得构建的向量空间模型具有了语义相关性,同时采用改进的TextRank算法提取文本关键字,增强了文本特征的表达并消除了大量冗余信息,降低了文本特征矩阵的稀疏性,使文本相似度的计算更加高效。不同模型的仿真实验结果表明,融合改进的TextRank算法与Bert词向量技术的方法具有更好的文本相似度计算性能。 展开更多
关键词 文本相似度 关键字提取 textRank算法 Bert 词向量技术 向量空间模型
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Automatic extraction and structuration of soil–environment relationship information from soil survey reports 被引量:8
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作者 WANG De-sheng LIU Jun-zhi +3 位作者 ZHU A-xing WANG Shu ZENG Can-ying MA Tianwu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2019年第2期328-339,共12页
In addition to soil samples, conventional soil maps, and experienced soil surveyors, text about soils(e.g., soil survey reports) is an important potential data source for extracting soil–environment relationships. Co... In addition to soil samples, conventional soil maps, and experienced soil surveyors, text about soils(e.g., soil survey reports) is an important potential data source for extracting soil–environment relationships. Considering that the words describing soil–environment relationships are often mixed with unrelated words, the first step is to extract the needed words and organize them in a structured way. This paper applies natural language processing(NLP) techniques to automatically extract and structure information from soil survey reports regarding soil–environment relationships. The method includes two steps:(1) construction of a knowledge frame and(2) information extraction using either a rule-based method or a statistic-based method for different types of information. For uniformly written text information, the rule-based approach was used to extract information. These types of variables include slope, elevation, accumulated temperature, annual mean temperature, annual precipitation, and frost-free period. For information contained in text written in diverse styles, the statistic-based method was adopted. These types of variables include landform and parent material. The soil species of China soil survey reports were selected as the experimental dataset. Precision(P), recall(R), and F1-measure(F1) were used to evaluate the performances of the method. For the rule-based method, the P values were 1, the R values were above 92%, and the F1 values were above 96% for all the involved variables. For the method based on the conditional random fields(CRFs), the P, R and F1 values for the parent material were, respectively, 84.15, 83.13, and 83.64%; the values for landform were 88.33, 76.81, and 82.17%, respectively. To explore the impact of text types on the performance of the CRFs-based method, CRFs models were trained and validated separately by the descriptive texts of soil types and typical profiles. For parent material, the maximum F1 value for the descriptive text of soil types was 90.7%, while the maximum F1 value for the descriptive text of soil profiles was only 75%. For landform, the maximum F1 value for the descriptive text of soil types was 85.33%, which was similar to that of the descriptive text of soil profiles(i.e., 85.71%). These results suggest that NLP techniques are effective for the extraction and structuration of soil–environment relationship information from a text data source. 展开更多
关键词 soil–environment relationship text natural LANGUAGE processing extraction STRUCTURATION
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