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In this paper, we propose a new language model, namely, a dependency structure language model, for topic detection and tracking (TDT) to compensate for weakness of unigram and bigram language models. The dependency structure language model is based on the Chow expansion theory and the dependency parse tree generated by a linguistic parser. So, long-distance dependencies can be naturally captured by the dependency structure language model. We carried out extensive experiments to verify the proposed model on topic tracking and link detection in TDT. In both cases, the dependency structure language models perform better than strong baseline approaches. 相似文献
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自然语言的理解是机器翻译(简称M T)的基础。机器理解汉语所面临的主要困难,包括自动分词,歧义消解,意义的多层次解读等。自然语言处理中的这些难题使得计算机难以对汉语语句做出正确的描述。基于规则的汉英机器翻译的质量还有待提高。基于语料库的方法为机器翻译研究提供了新的途径。将基于规则的理性主义方法同基于语料库的经验主义方法结合起来,必将极大地提高汉英机器的翻译的质量。 相似文献
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应用人工智能技术产生高速公路事件响应预案,提出了基于规则推理、案例推理和贝叶斯网络推理3种方法的事件响应框架. 首先, 建立了基于规则推理的高速公路事件管理系统(RK-IMS), 并应用于宁连高速公路北段事件管理过程中. 然后, 通过分析RK-IMS系统2年的运营数据, 确定了事件案例的结构表示与事件响应的贝叶斯网络结构. 最后, 应用k近邻算法计算相似性案例, 并研究了基于该算法的预案产生和控制策略. 利用2006年RK-IMS事件管理系统的实际数据对模型进行了验证. 对比分析结果表明, 该方法是有效可信的. 相似文献
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为了研究目前主流的异常检测算法,并了解基于相同数据集的异常检测算法之间性能的差异,首先简要分类综述现有异常检测技术,然后着重实验分析,选取5个具有代表性的异常检测算法,应用于10组不同维数和大小的标准数据集上,执行误差性能(FNR,FPR,AUC)对比,最后试验结果表明,基于统计的高斯混合(Gaussian Mixture)算法具有较大优势。 相似文献
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本文以LFG为基本参考模型,提出了一个具体语法开发平台的系统框架与功能结构。语法开发平台包括三个子系统:语法提取子系统、语法分析子系统、语义分析处理子系统。文章对语法提取子系统进行了全面的系统设计,既为语法分析子系统奠定了基础,又为构造具体的应用系统留有程序接口。 相似文献
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本文以数字图书馆的资源检索为应用背景,研究本体支持下的基于规则推理的语义检索机制.在本体知识库支持下,检索系统面向基于本体结构的元数据,依据概念关联及相关推理规则,寻求蕴涵关系,发掘隐含信息.本文从数字图书馆资源的语义关系中提炼出推理规则,并选用正向链推理算法实现推理,基于正向链接的规则推理依照事先定义的规则集,能够从已有事实出发挖掘已存事实中的隐含结论,适用于无确定推理目标且解空间很大的一类推理检索任务.本文通过实例分析验证了这一方法在智能检索系统中应用的可行性,并提出采用先推理后检索的策略解决在面向庞大数据集和复杂推理规则时产生的推理时效问题. 相似文献
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Shallow semantic parsing assigns a simple structure (such as WHO did WHAT to WHOM, WHEN, WHERE, WHY, and HOW) to each predicate in a sentence. It plays a critical role in event-based information extraction and thus is important for deep information processing and management. This paper proposes a tree kernel method for a particular shallow semantic parsing task, called semantic role labeling (SRL), with an enriched parse tree structure. First, a new tree kernel is presented to effectively capture the inherent structured knowledge in a parse tree by enabling the standard convolution tree kernel with context-sensitiveness via considering ancestral information of substructures and approximate matching via allowing insertion/deletion/substitution of tree nodes in the substructures. Second, an enriched parse tree structure is proposed to both well preserve the necessary structured information and effectively avoid noise by differentiating various portions of the parse tree structure. Evaluation on the CoNLL’2005 shared task shows that both the new tree kernel and the enriched parse tree structure contribute much in SRL and our tree kernel method significantly outperforms the state-of-the-art tree kernel methods. Moreover, our tree kernel method is proven rather complementary to the state-of-the-art feature-based methods in that it can better capture structural parse tree information. 相似文献
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杨婕 《青海师范大学学报(哲学社会科学版)》2012,(2):10-14
青海省经济快速发展的同时城乡二元经济问题日趋严重,并成为经济发展的障碍,本文运用实证分析与规范分析,依据青海省近三十年经济发展数据对青海城乡二元经济的表现,及对经济社会发展的现实和长远影响进行探讨和分析.通过分析,现阶段青海城乡二元经济对比是在扩大的,城镇化战略对缓解青海省城乡二元经济作用不显著.以此为基础对缓解青海城乡二元问题提供理论依据. 相似文献
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Priti Shankar 《Resonance》2007,12(8):8-26
The term compiler was coined in the late forties, by Grace Murray Hopper, a pioneer who rose to the challenges of programming the first computers.
The problem of translation from a source language into a target language was viewed as a ‘compilation’ of a sequence of machine
language subprograms selected from a library. In this article we briefly trace the evolution of compilers from their beginnings
as huge sprawling algorithms in the early fifties, to their current elegant, phase ordered forms.
Priti Shankar is with the Department of Computer Science and Automation at the Indian Institute of Science, Bangalore. Her
interests are in theoretical computer science and error correcting codes. 相似文献