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61.
62.
Relational database systems may serve to evaluate an open query under closed-world semantics. The evaluation returns an explicit output relation complemented with an often implicit statement about the completeness of that relation. The output relation is formed from all those tuples that both fit the format and satisfy the properties expressed in the query. Using first-order logic for specifying formal semantics, the output relation can be seen as a set of (ground) sentences obtained from the query formula by suitable substitutions of free variables by constants. A statement about the completeness of a relation can also explicitly be formalized as a sentence of first-order logic. Inference control for enforcing a confidentiality policy has to inspect and to possibly distort not only the sentences representing the tuples of the output relation but also the completeness sentences. Previously designed and formally verified control procedures employ theorem-proving for such inspections while iteratively considering candidates for those sentences and determining termination conditions, respectively. In this article, we outline an implementation of these control procedures and treat improvements of their runtime efficiency, in particular to overcome shortcomings of the underlying theorem prover, which is repeatedly called with an input comprising a completeness sentence of increasing size. The improvements are obtained by an equivalent rewriting of completeness sentences, exploiting the active domain or introducing new constants for combinations of the original constants, respectively, as well as by optimizing the number of such calls. Besides theoretical complexity considerations, we also present practical evaluations for some examples. These examples include queries that—without control—would return the whole underlying database relations and—with control—can be used for confidentiality-preserving data publishing. 相似文献
63.
Current models of bilingualism (e.g., BIA+) posit that lexical access during reading is not language selective. However, much of this research is based on the comprehension of words in isolation. The authors investigated whether nonselective access occurs for words embedded in biased sentence contexts (e.g., A. I. Schwartz & J. F. Kroll, 2006). Eye movements were recorded as French–English bilinguals read English sentences containing cognates (e.g., piano), interlingual homographs (e.g., coin, meaning corner in French), or matched control words. Sentences provided a low or high semantic constraint for target-language meanings. Both early-stage comprehension measures (e.g., first fixation duration, gaze duration, and skipping) and late-stage comprehension measures (e.g., go-past time and total reading time) showed significant cognate facilitation and interlingual homograph interference for low-constraint sentences. For high-constraint sentences, however, only early-stage comprehension measures were consistent with nonselective access. There was no evidence of cognate facilitation or interlingual homograph interference for late-stage comprehension measures. Thus, nonselective bilingual lexical access at early stages of comprehension is rapidly resolved in semantically biased contexts at later stages of comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
64.
Tun Patricia A.; Benichov Jonathan; Wingfield Arthur 《Canadian Metallurgical Quarterly》2010,25(3):730
Older adults with good hearing and with mild-to-moderate hearing loss were tested for comprehension of spoken sentences that required perceptual effort (hearing speech at lower sound levels), and two degrees of cognitive load (sentences with simpler or more complex syntax). Although comprehension accuracy was equivalent for both participant groups and for young adults with good hearing, hearing loss was associated with longer response latencies to the correct comprehension judgments, especially for complex sentences heard at relatively low amplitudes. These findings demonstrate the need to take into account both sensory and cognitive demands of speech materials in older adults' language comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
Staub Adrian; Grant Margaret; Clifton Charles Jr.; Rayner Keith 《Canadian Metallurgical Quarterly》2011,37(5):1326
In this brief rejoinder, we respond to Farmer, Monaghan, Misyak, and Christiansen (2011). We argue that the data still do not support the claim that reading time is affected by the phonological typicality of a word for its part of speech. We also question Farmer et al.'s claim that interleaving syntactic structures in an experiment modifies grammatically based syntactic expectations. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
66.
基于实例的机器翻译系统需要双语句对的支持。为大量获取双语句对,则需要以篇章对齐的双语文本为输入,实现句子的自动对齐。通过分析汉英双语法律文本的特征,提出了法律文本对齐假设。首先识别出法规源文和译文中的结构标识和句子,然后在句子一级对齐法律文本。该方法在150篇汉英法律文本语料上,取得了80.98%的对齐准确率。 相似文献
67.
基于C/C++与ORACLE9i的嵌入式SQL编程技术 总被引:6,自引:4,他引:6
针对嵌入式SQL编程技术,本文论述了C/C 语言与ORACLE9i的嵌入式SQL的形式,嵌入式SQL语句与C/C 宿主语言之间的通信.并给出了代码实例。 相似文献
68.
基于长度的扩展方法的汉英句子对齐 总被引:7,自引:4,他引:7
本文提出了一种用于汉英平行语料库对齐的扩展方法。该扩展方法以基于长度的统计对齐方法为主,然后根据双语词典引入了词汇信息,而基于标点的方法作为对齐的后处理部分。这种扩展方法不仅避免了复杂的中文处理,例如,汉语分词和词性标注,而且在统计方法中引入了关键词信息,以提高句子对齐的正确率。本文中所用的双语语料是LDC 的关于香港的双语新闻报道。动态规划算法用于系统的实现。和单纯的基于长度的方法和词汇方法相比,我们的扩展方法提高了句子对齐的正确率,并且结果是比较理想的。 相似文献
69.
句型转换是指将感叹句和各种疑问句变为陈述句语序的转换。我们在研制MatLink英汉机器翻译系统的过程中,提出了扩展的基于信息的格语法(EICG)及其应用原则,并且利用EICG设计实现了英语句型转换器。该分析器采用多出口结构,针对感叹句和不同类型疑问句提出相应的分析实现算法,并通过实例分析阐述了实现不同句型间转换的设计思想和工作过程。 相似文献
70.
The programming technology about Embedded SQL discuss the form of Embedded SQL base on C/C language and ORACLE9i DBMS in this paper. We have also discussed the communications between the sentence of Embedded SQL and C/C language and have provided the code. 相似文献