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121.
本文根据特征平行四边形法和N/(1/2)比值法提出了一种简便快速的电子衍射谱分析方法——图表法,由于它以一些简单的操作取代了常用分析法的数据测量和计算过程,因此具有简便、快速、可靠性高等优点。 相似文献
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为了有效管理数量庞大的业务过程模型,提高检索效率,分析了实际业务过程模型的特点,分析比较了已有的图数据库索引技术和业务过程模型检索的已有研究成果,结果表明,BeehiveZ系统能比较好地结合业务过程模型的特点进行检索,但还需要在嵌套模型检索和基于双互向模拟的模型相似性度量方面开展进一步的工作。 相似文献
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赵国华 《机械制造与自动化》2011,40(2):30-32
介绍了某厂滚齿机、插齿机、数控回转工作台等产品的关键部件——分度蜗杆副的制造,系统地分析了从设计图样、工艺路线、加工设备直至刀具、检验测量各个环节存在的问题,提出了攻关方案并付诸实施,取得了很好的成绩,制造精度由6~5级提高至4级。 相似文献
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Rong Zhao 《Pattern recognition》2002,35(3):593-600
In this paper, we present the results of a project that seeks to transform low-level features to a higher level of meaning. This project concerns a technique, latent semantic indexing (LSI), in conjunction with normalization and term weighting, which have been used for full-text retrieval for many years. In this environment, LSI determines clusters of co-occurring keywords, sometimes, called concepts, so that a query which uses a particular keyword can then retrieve documents perhaps not containing this keyword, but containing other keywords from the same cluster. In this paper, we examine the use of this technique for content-based image retrieval, using two different approaches to image feature representation. We also study the integration of visual features and textual keywords and the results show that it can help improve the retrieval performance significantly. 相似文献
128.
A method is described to extract an index from a binary character image for database storage and retrieval. The index is hierarchical in nature, and different parts can retrieve character image clusters of different sizes. A hierarchy of Kohonen neural networks is used to generate the clusters on which the indexing method is based. The application is the identification of the font from a sample of printed characters. This is particularly important for forensic document examiners who may have to match a document of unknown origin with the equipment that may have produced it. A computerised system is expected to considerably reduce the time required for each document search. 相似文献
129.
在X射线衍射仪上收集了Bi_4(SiO_4)_3的衍射数据;利用Rietveld方法对衍射数据进行指标化,F_(30)=158.90;确定了Bi_4(SiO_4)_3的晶体结构参数。结果发现:该结构中硅氧四面体是变形的孤立四面体,其中两个O-Si-O键角为107.13°,而另两个为114.26°,详细报道了晶体结构,给出了晶体结构图;提出Bi离子最外层孤对的6s2电子的存在是形成这种变形配位多面体的原因。 相似文献
130.
We are currently developing unified query processing strategies for image databases. To perform this task, model-based representations of images by content are being used, as well as a hierarchical generalization of a relatively new object-recognition technique called data-driven indexed hypotheses. As the name implies, it is index-based, from which its efficiency derives. Earlier approaches to data-driven model-based object recognition techniques were not capable of handling complex image data containing overlapping, partially visible, and touching objects due to the limitations of the features used for building models. Recently, a few data-driven techniques capable of handling complex image data have been proposed. In these techniques, as in traditional databases, iconic index structures are employed to store the image and shape representation in such a way that searching for a given shape or image feature can be conducted efficiently. Some of these techniques handle the insertion and deletion of shapes and/or image representations very efficiently and with very little influence on the overall system performance. However, the main disadvantage of all previous data-driven implementations is that they are main memory based. In the present paper, we describe a secondary memory implementation of data-driven indexed hypotheses along with some performance studies we have conducted. 相似文献