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1.
Online review mining has been used to help manufacturers and service providers improve their products and services, and to provide valuable support for consumer decision making. Product aspect extraction is fundamental to online review mining. This research is aimed to improve the performance of aspect extraction from online consumer reviews. To this end, we augment a frequency-based extraction method with PMI-IR, which utilizes web search in measuring the semantic similarity between aspect candidates and target entities. In addition, we extend RCut, an algorithm originally developed for text classification, to learn the threshold for selecting candidate aspects. Experiment results with Chinese online reviews show that our proposed method not only outperforms the state of the art frequency-based method for aspect extraction but also generalizes across different product domains and various data sizes.  相似文献   
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为建立知识管理系统的自学习与自组织机制,本文将基于案例推理的技术思想引入知识管理自学习子系统,对知识管理自学习案例的平行结构体方面相似度进行系统而深入地研究。首先,论文对相关文献进行述评,阐明了本文研究的出发点,诠释了知识管理自学习案例平行结构体方面的内涵及其特征;继而,分七种情况深入讨论了平行结构体方面维度相似度的计算方法,并在此基础上提出了方面相似度的计算策略;最后,通过算例分析了相关技术策略与实施细节。  相似文献   
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Aspect mining, which aims to extract ad hoc aspects from online reviews and predict rating or opinion on each aspect, can satisfy the personalized needs for evaluation of specific aspect on product quality. Recently, with the increase of related research, how to effectively integrate rating and review information has become the key issue for addressing this problem. Considering that matrix factorization is an effective tool for rating prediction and topic modeling is widely used for review processing, it is a natural idea to combine matrix factorization and topic modeling for aspect mining (or called aspect rating prediction). However, this idea faces several challenges on how to address suitable sharing factors, scale mismatch, and dependency relation of rating and review information. In this paper, we propose a novel model to effectively integrate Matrix factorization and Topic modeling for Aspect rating prediction (MaToAsp). To overcome the above challenges and ensure the performance, MaToAsp employs items as the sharing factors to combine matrix factorization and topic modeling, and introduces an interpretive preference probability to eliminate scale mismatch. In the hybrid model, we establish a dependency relation from ratings to sentiment terms in phrases. The experiments on two real datasets including Chinese Dianping and English Tripadvisor prove that MaToAsp not only obtains reasonable aspect identification but also achieves the best aspect rating prediction performance, compared to recent representative baselines.  相似文献   
5.
Most document clustering algorithms operate in a high dimensional bag-of-words space. The inherent presence of noise in such representation obviously degrades the performance of most of these approaches. In this paper we investigate an unsupervised dimensionality reduction technique for document clustering. This technique is based upon the assumption that terms co-occurring in the same context with the same frequencies are semantically related. On the basis of this assumption we first find term clusters using a classification version of the EM algorithm. Documents are then represented in the space of these term clusters and a multinomial mixture model (MM) is used to build document clusters. We empirically show on four document collections, Reuters-21578, Reuters RCV2-French, 20Newsgroups and WebKB, that this new text representation noticeably increases the performance of the MM model. By relating the proposed approach to the Probabilistic Latent Semantic Analysis (PLSA) model we further propose an extension of the latter in which an extra latent variable allows the model to co-cluster documents and terms simultaneously. We show on these four datasets that the proposed extended version of the PLSA model produces statistically significant improvements with respect to two clustering measures over all variants of the original PLSA and the MM models.  相似文献   
6.
黄河源区玛多县草地覆被变化分析   总被引:6,自引:1,他引:5  
张帅  邵全琴  刘纪远  徐新良 《资源科学》2008,30(10):1547-1554
草地是黄河源区最主要的覆被类型,采用黄河源区玛多县1977年、1990年和2003年3期夏季时相的MSS/TM遥感影像,通过人机交互式目视解译方法,首次采用草地覆被变化分类系统,提取了玛多县1977年~2003年间草地覆被时空变化特征,在此基础上分析了玛多县20世纪70年代以来的草地覆被时空变化特征,以及草地覆被变化与高程、坡度和坡向之间的关系。主要结论有:①玛多县的草地退化格局在20世纪70年代已经基本形成,之后退化过程一直持续发生,1990年~2003年间退化程度略有加强;②草地覆被变化以轻度和中度退化为主,主要类型为破碎化和覆盖度下降,这2种类型对应的草地面积比重为27.62%;③草地覆被变化主要发生在海拔4 200m~4 700m的范围;④草地覆被变化主要发生在坡度0°~15°范围内,在此以上的坡度发生的变化较少,坡度在5°以下时,各种草地覆被变化类型的发生随着坡度的增加而增加,当坡度大于12°时,变化的发生随着坡度的增加而减少;⑤随着坡向的变化,草地覆被的变化的发生没有太大的差异。  相似文献   
7.
Aspect level sentiment analysis is important for numerous opinion mining and market analysis applications. In this paper, we study the problem of identifying and rating review aspects, which is the fundamental task in aspect level sentiment analysis. Previous review aspect analysis methods seldom consider entity or rating but only 2-tuples, i.e., head and modifier pair, e.g., in the phrase “nice room”, “room” is the head and “nice” is the modifier. To solve this problem, we novelly present a Quad-tuple Probability Latent Semantic Analysis (QPLSA), which incorporates entity and its rating together with the 2-tuples into the PLSA model. Specifically, QPLSA not only generates fine-granularity aspects, but also captures the correlations between words and ratings. We also develop two novel prediction approaches, the Quad-tuple Prediction (from the global perspective) and the Expectation Prediction (from the local perspective). For evaluation, systematic experiments show that: Quad-tuple PLSA outperforms 2-tuple PLSA significantly on both aspect identification and aspect rating prediction for publication datasets. Moreover, for aspect rating prediction, QPLSA shows significant superiority over state-of-the-art baseline methods. Besides, the Quad-tuple Prediction and the Expectation Prediction also show their strong ability in aspect rating on different datasets.  相似文献   
8.
波兰哲学家、文艺美学家罗曼.英伽登将现象学方法运用到美学研究上,对文学的艺术作品的基本结构和存在方式予以描述。作为一种独特的存在领域,文学的艺术作品既不是实在的客体,也不是观念的客体,而是一种意向性客体;文学的艺术作品在审美上由语音层、意义层、再现客体层和图式观相层构成,实际只是一种图式化结构,只有当这些构成要素在阅读中被读者具体化时,文学的艺术作品才成其为审美对象。罗曼.英伽登关于文学作品结构的思想,已经被人们普遍地接受为进一步思考的出发点。  相似文献   
9.
传统意义上,回指主要指篇章中指称代词、名词与其先行词的对应关系。作为语言一种范畴和语义表现形式,体貌作为语篇回指研究的可能性以及回指机制的研究未能得到重视和深入的研究。本文采用兰纳克的认知语法体貌分析框架,依据回指研究的基本理念,尝试勾画出认知语法视角下的体貌回指认知图示。  相似文献   
10.
在现代英语中,动词进行体的使用非常广泛,引起了国内外许多学者广泛关注和研究。他们主要从语义实质、语用功能、be动词进行体、语篇连贯和英汉对比等方面进行了深入的研究。  相似文献   
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