共查询到20条相似文献,搜索用时 0 毫秒
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Li Tianzhu 《计算机科学技术学报》1992,7(4):356-362
Static optimization of logical queries is,in substance,to move selections down as far as possible in evaluating logical queries.This paper extends Ullman‘s RGG(Rule/Goal Graph)^[6] and introduces Pgraph,with which a wide range of recursive logical queries can be statically optimized top-down and evaluated bottom-up,some of which are usually optimized by dynamic approaches.The paper also shows that for some logical queries the complexity of pushing selections down and computing bottom-up is related to the complexity of base relation in the queries. 相似文献
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基于中间语言的翻译系统的关键是中间语言设计。文中介绍了汉英翻译系统ICENT 中间语言设计,实用的角度出发,在内容上权衡了语法和语义知识的比例,并根据汉英两种语言的特点,采用框架结构,通过描述词之间的语法关系来描述整个句子的结构,取得了比较满意的结果。 相似文献
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一个基于GLR算法的英汉机器翻译浅层句法分析器 总被引:5,自引:0,他引:5
浅层句法分析是指短语级的自然语言句法分析。在研制MatLink英汉机器翻译系统的过程中,提出了扩充的CFG文法用于描述英语短语句法,并改进了GLR算法,设计实现了用于英汉翻译的英语浅层句法分析器。该分析器采用多出口的分析表结构,引入符号映射函数实现短语边界的自动识别,用孩子兄弟树描述短语的句法结构,并通过短语转换模式实现源语言向目标语言的短语级转换。最后,通过对一个实例句子的分析阐述了该浅层句法分析器的设计思想和工作过程。 相似文献
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藏汉机器翻译技术跟汉英机器翻译技术有所不同,其中,很重要的一个方面,藏语更依赖于格助词等虚词在句子中的作用,格助词种类繁多,用法差异很大。针对藏语格助词进行分析,在藏语短语句法树库的基础上,加入了藏语本体特征的语义信息,形成融合藏语语义信息的藏汉机器翻译方法。通过对比基于短语和句法的实验分析,该方法可以很好地应用于藏汉机器翻译系统。 相似文献
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本文介绍了汉英机器翻译系统中从中间媒介语言生成英语的生成系统的词汇结构和功能,描述了生成系统各个层次之间的转换原理。为了说明清楚,在叙述中注意了列举从中间媒介中间媒介语言到目标语句的生成实例。 相似文献
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Sergei Nirenburg 《Machine Translation》1989,4(1):5-24
This paper provides an overview of the KBMT-89 project at Carmegie Mellon University's Center for Machine Translation, as well therefore of the special number of this journal, which reports on the project. The knowledge-based approach to machine translation is presented and defended in a historical context. Various components of the system, key parts of which are described in subsequent papers of the issue, are introduced and paired with their computational motivations. 相似文献
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Toward a lexicalized grammar for interlinguas 总被引:1,自引:0,他引:1
In this paper we present one aspect of our research on machine translation (MT): capturing the grammatical and computational relation between (i) the interlingua (IL) as defined declaratively in the lexicon and (ii) the IL as defined procedurally by way of algorithms that compose and decompose pivot IL forms. We begin by examining the interlinguas in the lexicons of a variety of current IL-based approaches to MT. This brief survey makes it clear that no consensus exists among MT researchers on the level of representation for defining the IL. In the section that follows, we explore the consequences of this missing formal framework for MT system builders who develop their own lexical-IL entries. The lack of software tools to support rapid IL respecification and testing greatly hampers their ability to modify representations to handle new data and new domains. Our view is that IL-based MT research needs both (a) the formal framework to specify possible IL grammars and (b) the software support tools to implement and test these grammars. With respect to (a), we propose adopting a lexicalized grammar approach, tapping research results from the study oftree grammars for natural language syntax. With respect to (b), we sketch the design and functional specifications for parts of ILustrate, the set of software tools that we need to implement and test the various IL formalisms that meet the requirements of a lexicalized grammar. In this way, we begin to address a basic issue in MT research, how to define and test an interlingua as a computational language — without building a full MT system for each possible IL formalism that might be proposed. 相似文献
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Although many linguistic theories and formalisms have been developed and discussed on the problem of parsing algorithm in the past decades,the efficiency and accuracy of parsing are still serious problems in practical machine translation systems.This paper presents a parsing algorithm wit dynamic rule selection and the experimental results.By describing the design and practice of the inproved algorithm ,the paper discusses in detail the designing method for a high speed and efficient parser. 相似文献
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This article presents translations of works by Troyanskii describing his 1933 proposals for a mechanical translation device, some later elaborations of the linguistic and technical features, and also translated extracts from commentaries made in 1959 by the Russian editors of his papers. The paper includes extensive assessments of Troyanskii's proposals, and places his work in the context of his time and in the light of subsequent research in machine translation. 相似文献
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A common problem when writing compilers for programming languages or little, domain‐specific languages is that an input token may have several interpretations, depending on context. Solutions to this problem demand programmer intervention, obfuscate the language's grammar, and may introduce subtle bugs. We present a technique which is simple and without the above drawbacks—allowing a token to simultaneously have different types—and show how it can be applied to areas such as little language processing and fuzzy parsing. We also describe ways that compiler tools can support this technique. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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稀疏数据严重影响句子结构分析模型的结果, 而句法结构是语义内容和句法分析形式的结合。本文在语义结构信息标注的基础上提出了一种基于语义搭配关系的词聚类模型和算法,建立基于语义类的头驱动句子结构分析统计模型。该语言模型不但比较成功地解决了数据稀疏问题, 而且句子结构分析系统性能也有了明显的提高。句子结构分析实验结果表明,基于语义类的头驱动的句子结构分析统计模型,其召回率和精确率的值相应为88.26%和88.73%,综合指标改进了8.39%。 相似文献
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句子的语义处理是自然语言处理的重要难题与挑战。抽象语义表示(Abstract meaning representation, AMR)是近几年国际上新兴的句子级语义表示方法,突破了传统的句法树结构的限制,将一个句子语义抽象为一个单根有向无环图,很好地解决了论元共享问题,成为语言资源建设和句子语义解析的研究热点。本文从AMR概念与规范、解析算法和应用等方面对AMR相关研究进行系统的梳理,特别对AMR的各种解析算法进行了比较深入的分析和比较,指出了现有算法存在的问题和不足,同时介绍了中文AMR的开发进展,最后展望了AMR未来的研究方向。 相似文献
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该文通过研究国内外相关的句法分析算法与理论,再结合维吾尔语自身的特点对基于规则的维吾尔语句法分析方法进行讨论,由于维吾尔语作为一种自然语言,具有自然语言所共有的一些规则,发现国外经典的句法分析方法同样适合于维吾尔语的句法分析,本论文主要讨论了自项向下的的自动句法分析方法。 相似文献
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专利文献翻译中并列结构的处理 总被引:1,自引:0,他引:1
针对专利文献翻译中的复杂并列结构的处理,提出了一种预处理和后处理的方法——拆分合并法。它弥补了统计翻译系统在复杂结构方面的劣势,同时保留统计翻译在经验句式、人力成本等方面优于规则系统的特点。实验表明,这种方法稳定地提高了翻译系统的准确率。此外,它独立于具体的统计翻译系统,可以方便地移植到不同的统计翻译系统上。 相似文献
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为解决基于短语统计机器翻译存在的调序能力不足的问题,尝试利用句法分析器对基于短语统计机器翻译的输入汉语句子进行句法分析,然后利用转换器进行调序操作,并对部分类型短语进行预先翻译,然后再利用基于短语统计机器翻译的解码器进行翻译。重点测试了汉语中“的”字引导的复杂定语调序、介词短语、特定搭配短语、方位词短语的调序及预翻译产生的效果。实验结果表明,这些调序及预翻译操作可以显著地提高基于短语的统计机器翻译的英文译文结果的BLEU值。 相似文献
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针对现代藏语句法,在参照宾大中文树库的基础上,构建藏语短语句法树库,并建立了树库编辑工具,为藏汉机器翻译服务。在短语句法树库的基础上,提出一种融合藏语句法特征的藏汉机器翻译方法。实验分析结果表明,该方法可以很好地应用于藏汉机器翻译系统。 相似文献
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在统一框架下对双语语料库的平行文档进行分析建模,提取语言之间的潜在语义对应关系,在潜在中间语义空间中进行检索,从而实现跨语言信息检索.作者在自建的中英平行语料库和蒙特利尔大学提供的英法平行语料库基础上,对平行文档进行分析建模,在TREC5&9和SDA数据集上进行了中、英、法三种语言的跨语言信息检索实验,且与单语言的信息检索模型进行了比较,实验结果显示本文的模型表现了较好的性能. 相似文献