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981.
提出了一种新的相似视频快速检索方法.根据视频的时空分布统计得到图像特征码和视频单元,通过统计视频单元数量度量视频相似性.为了适应可扩展计算的需要,提出了基于聚类索引表的检索方法.通过对大规模数据库的查询测试证明该相似性检索算法快速有效.  相似文献   
982.
马荣康  王艺棠 《科研管理》2021,42(5):153-160
随着我国发明专利申请数量的迅猛增加,如何通过事前和事后指标测度并识别技术和经济价值高的突破性技术发明就成为学术界面临的焦点问题。针对我国专利普遍缺乏引文信息的现状,本文利用专利的国际专利分类(IPC)信息构建两两专利相似度指标,并引入时间维度对过去、当前以及未来三个时间段的专利相似度比较,测度专利的新颖性、独特性和影响力,从而构建突破性技术发明的综合识别方案。然后,以纳米技术为例,利用美国专利商标局(USPTO)在1975-2015年的授权发明专利数据进行实证检验。结果表明:(1)基于专利IPC四位和六位分类的相似度指标分别可以识别出6.23%和5.06%的纳米技术专利为突破性技术发明;(2)基于专利相似度识别的突破性技术发明与基于专利被引数识别的突破性技术发明具有显著的正相关关系,但是,两类识别方法得到的结果中仅有不足总样本的0.5%是相同的,表明以往单纯依赖专利被引数据识别突破性技术发明可能存在一定偏差;(3)对突破性技术发明来源特征的实证检验表明,基于专利相似度和基于专利被引数的突破性技术发明的发明人和组织来源特征基本一致,而发明层面的知识来源特征呈现不一致的结果,进一步反映出两类识别方案的差异性。本文基于专利相似度构建的突破性技术发明识别方案既为企业在实践中挖掘和利用高价值的发明专利提供参考,也对未来突破性技术发明相关研究达成一致结论具有重要意义。  相似文献   
983.
Machine reading comprehension (MRC) is a challenging task in the field of artificial intelligence. Most existing MRC works contain a semantic matching module, either explicitly or intrinsically, to determine whether a piece of context answers a question. However, there is scant work which systematically evaluates different paradigms using semantic matching in MRC. In this paper, we conduct a systematic empirical study on semantic matching. We formulate a two-stage framework which consists of a semantic matching model and a reading model, based on pre-trained language models. We compare and analyze the effectiveness and efficiency of using semantic matching modules with different setups on four types of MRC datasets. We verify that using semantic matching before a reading model improves both the effectiveness and efficiency of MRC. Compared with answering questions by extracting information from concise context, we observe that semantic matching yields more improvements for answering questions with noisy and adversarial context. Matching coarse-grained context to questions, e.g., paragraphs, is more effective than matching fine-grained context, e.g., sentences and spans. We also find that semantic matching is helpful for answering who/where/when/what/how/which questions, whereas it decreases the MRC performance on why questions. This may imply that semantic matching helps to answer a question whose necessary information can be retrieved from a single sentence. The above observations demonstrate the advantages and disadvantages of using semantic matching in different scenarios.  相似文献   
984.
Automatically assessing academic papers has enormous potential to reduce peer-review burden and individual bias. Existing studies strive for building sophisticated deep neural networks to identify academic value based on comprehensive data, e.g., academic graphs and full papers. However, these data are not always easy to access. And the content of the paper rather than other features outside the paper should matter in a fair assessment. Furthermore, while BERT models can maintain general semantics by pre-training on large-scale corpora, they tend to be over-smoothing due to stacked self-attention layers among unfiltered input tokens. Therefore, it is nontrivial to figure out distinguishable value of an academic paper from its limited content. In this study, we propose a novel deep neural network, namely Dual-view Graph Convolutions Enhanced BERT (DGC-BERT), for academic paper acceptance estimation. We combine the title and abstract of the paper as input. Then, a pre-trained BERT model is employed to extract the paper’s general representations. Apart from hidden representations of the final layer, we highlight the first and last few layers as lexical and semantic views. In particular, we re-examine the dual-view filtered self-attention matrices via constructing two graphs, respectively. After that, two multi-hop Graph Convolutional Networks (GCNs) are separately employed to capture pivotal and distant dependencies between the tokens. Moreover, the dual-view representations are facilitated by each other with biaffine attention modules. And a re-weighting gate is proposed to further streamline the dual-view representations with the help of the original BERT representation. Finally, whether the submitted paper could be acceptable is predicted based on the original language model features cooperated with the dual-view dependencies. Extensive data analyses and the full paper based MHCNN studies provide insights into the task and structural functions. Comparison experiments on two benchmark datasets demonstrate that the proposed DGC-BERT significantly outperforms alternative approaches, especially the state-of-the-art models like MHCNN and BERT variants. Additional analyses reveal significance and explainability of the proposed modules in the DGC-BERT. Our codes and settings have been released on Github (https://github.com/ECNU-Text-Computing/DGC-BERT).  相似文献   
985.
We study the selection of transfer languages for different Natural Language Processing tasks, specifically sentiment analysis, named entity recognition and dependency parsing. In order to select an optimal transfer language, we propose to utilize different linguistic similarity metrics to measure the distance between languages and make the choice of transfer language based on this information instead of relying on intuition. We demonstrate that linguistic similarity correlates with cross-lingual transfer performance for all of the proposed tasks. We also show that there is a statistically significant difference in choosing the optimal language as the transfer source instead of English. This allows us to select a more suitable transfer language which can be used to better leverage knowledge from high-resource languages in order to improve the performance of language applications lacking data. For the study, we used datasets from eight different languages from three language families.  相似文献   
986.
Recently, graph neural network (GNN) has been widely used in sequential recommendation because of its powerful ability to capture high-order collaborative relations, greatly promoting recommendation performance. However, some existing GNN-based methods fail to make full use of multiple relevant features of nodes and ignore the impact of semantic association between nodes on extracting user preferences. To this end, we propose a multi-feature fused collaborative attention network MASR, which sufficiently learns the temporal and positional features of nodes, and innovatively measures the importance of these two features for analyzing the nodes’ dynamic patterns. In addition, we incorporate semantic-enriched contrastive learning into collaborative filtering to enhance the semantic association between nodes and reduce the noise from the structural neighborhood, which has a positive effect on the sequential recommendation. Compared with the baseline models, the performance of MASR on MovieLens, CDs and Beauty datasets is improved by 2.0%, 2.1% and 1.7% respectively, proving its effectiveness in the sequential recommendation.  相似文献   
987.
郭水良 《科技通报》1998,14(5):369-372
应用七级目测法对浙江金华地区16个麦田样点中随机取样的160个样方的杂草进行了优势度等级调查,将所得数据转换成重要值。以杂草在16个样点中的重要值为运算指标,应用主成分分析和图论聚类中的最小生成树法,对22种杂草的生态学相似性进行了比较。结果表明,22种杂草中,野燕麦与猪殃殃、波斯婆婆纳、卷耳、艾蒿及荠菜等杂草的生态学相似性较大,而看麦娘与雀舌草、牛繁缕、水苦荬则与棒头草、稻槎菜、一年蓬及Wang  相似文献   
988.
同训是《尔雅.释诂》中使用最多的一种训释方式。但是,所谓的“同训”并不是如字面上所讲的“同义互训”。有的“同训”是利用释词的一个义素来解释一组被释词,有的“同训”则是利用释词的几个完全不同的义素来解释几组被释词。由于同训方式的不同,这些被释词形成了不同的语义场。  相似文献   
989.
海量科学文献和数据为科学研究和交流带来了前所未有的巨大挑战,而传统出版物存在机器可读性差、缺乏知识关联性、不利于新的科学结论发现与传播等不足。本文以概念网络联盟(Concept Web Alliance)提出的纳米出版物模式(Nanopublication)为例,介绍面向大数据处理的新的知识资源语义表示、组织和出版模式,介绍其含义、核心模型、表示形式、构建方法,并从出版、知识组织、知识服务等多角度探讨其应用价值,以期为研究者了解知识资源的语义表达、组织和出版提供参考和帮助。图3。表1。参考文献18。  相似文献   
990.
本文在了解分布式数据库概念及分布式查询优化方法的基础上,主要讨论了如何利用语义信息对分布查询进行优化,以期达到提高查询效率,缩短响应时间的目的。  相似文献   
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