共查询到20条相似文献，搜索用时 672 毫秒
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提出一种基于贝叶斯惊奇计算的视频异常检测方法.用块匹配运动估计方法提取运动特征(如运动幅度、方向),得到多尺度运动矢量直方图.使用空间维度与时间维度上惊奇计算相结合的度量方法,既可以检测“个体异常行为”,也可以应用于“群体异常行为”检测.实验表明,该算法是鲁棒和实用的,且易于实现. 相似文献
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在视频序列中,帧与帧之间存在着很大的空间冗余度,通常要进行运动估计,以去除帧间的冗余信息,保留相关有效信息。运动估计算法很多,常用的简单有效的运动估计算法是块匹配算法,本文通过使用常用序列,对几种块匹配算法(BMA)进行测试比较,最后给出了一种新的匹配算法。 相似文献
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以MODIS/NDVI作为研究植被变化的遥感数据,针对传统变化矢量分析方法无法较好反映植被变化方向性与波动性的不足,本文建立了修正的变化矢量分析公式,并提出了可描述NDVI年际变化波动性的振荡指数bz。为验证修正的变化矢量分析方法与振荡指数的有效性,选取长江上游青衣江流域为试验区,对不同的植被变化检测方法进行比较分析。研究表明:利用修正变化矢量分析方法得到的NDVI矢量变化强度不仅保留了NDVI变化的强度特征和结构特征,而且可以明确地指示每个像元上植被的变化趋势,从而在数量上和趋势上更好地刻画NDVI时空变化特征;基于振荡指数bz计算的振荡强度由于考虑了年内各时间维上NDVI的变化累积,可以有效地反映NDVI年际变化的波动性。 相似文献
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利用中国省域工业面板数据,采用永续盘存法估算了研发资本存量,基于空间面板计量经济模型,实证分析了省域企业、大学研发及产学合作研发投入对工业创新绩效的贡献。结果表明,没有考虑空间依赖性和异质性的经典OLS方法获得的估计结果有偏,而考虑空间效应的空间面板计量模型修正了经典估计结果;省域工业专利和新产品创新存在明显的空间自相关性和依赖性,专利创新存在空间邻近局域集群效应而新产品创新存在空间邻近局域溢出效应,企业研发资本和人力投入对工业创新绩效的贡献显著,但大学研发的影响不明显,产学合作和人力资本的贡献显著,该结论对提升区域工业协同创新能力意义重大。 相似文献
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提出一种新的运动估计快速块匹配算法,基于运动场预测的三角形块运动估计搜索算法（PMVTEXBS）.该算法利用序列图像运动矢量场所具有的中心偏置性和空间相关性,结合“足够好就停止搜索”的思想和六边形搜索模式的高速特性,能快速找到匹配点。并且在块失真度量中使用改进的部分失真准则,进一步降低了算法复杂度。实验结果表明,和菱形算法DS、预测运动场自适应搜索算法（PMVAFST）相比,该算法的计算复杂度和搜索点数都有了明显下降;同时,它的图像质量要优于DS算法,和PMVAFST算法相比只有较小的下降。 相似文献
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用户兴趣的度量和用户兴趣的修正是个性化服务研究的重要内容。本文以用户最小浏览行为组合为基础,通过引入页面浏览率,改进页面驻留时间的计算方法,建立以页面浏览率、驻留时间和浏览速度为变量的兴趣度估计函数,提高用户兴趣度估计的准确性。同时,本文还将兴趣度导入到向量空间模型,采用二层树状结构表示用户兴趣,并提出用户兴趣定期修正方法,以缓解用户兴趣实时修正带来系统性能的下降。 相似文献
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This paper proposes an online video-based approach to handwritten Arabic alphabet recognition. Various temporal and spatial feature extraction techniques are introduced. The motion information of the hand movement is projected onto two static accumulated difference images according to the motion directionality. The temporal analysis is followed by two-dimensional discrete cosine transform and Zonal coding or Radon transformation and low pass filtering. The resulting feature vectors are time-independent thus can be classified by a simple classification technique such as K Nearest Neighbor (KNN). The solution is further enhanced by introducing the notion of superclasses where similar classes are grouped together for the purpose of multiresolutional classification. Experimental results indicate an impressive 99% recognition rate on user-dependant mode. To validate the proposed technique, we have conducted a series of experiments using Hidden Markov models (HMM), which is the classical way of classifying data with temporal dependencies. Experimental results revealed that the proposed feature extraction scheme combined with simple KNN yields superior results to those obtained by the classical HMM-based scheme. 相似文献
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《Information processing & management》2023,60(5):103447
Learning a continuous dense low-dimensional representation of knowledge graphs (KGs), known as knowledge graph embedding (KGE), has been viewed as the key to intelligent reasoning for deep learning (DL) and gained much attention in recent years. To address the problem that the current KGE models are generally ineffective on small-scale sparse datasets, we propose a novel method RelaGraph to improve the representation of entities and relations in KGs by introducing neighborhood relations. RelaGraph extends the neighborhood information during entity encoding, and adds the neighborhood relations to mine deeper level of graph structure information, so as to make up for the shortage of information in the generated subgraph. This method can well represent KG components in a vector space in a way that captures the structure of the graph, avoiding underlearning or overfitting. KGE based on RelaGraph is evaluated on a small-scale sparse graph KMHEO, and the MRR reached 0.49, which is 34 percentage points higher than that of the SOTA methods, as well as it does on several other datasets. Additionally, the vectors learned by RelaGraph is used to introduce DL into several KG-related downstream tasks, which achieved excellent results, verifying the superiority of KGE-based methods. 相似文献
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跨界水冲突、合作与全球水政治关系时空演化 总被引：1，自引：0，他引：1
全球水资源危机不断凸显,水资源矛盾不断激化,国家（地区）间水政治关系已成为国际社会亟需面对和解决的复杂地缘关系之一。基于1948—2008年国际水事件数据库数据,以“嵌入型”视角从冲突、合作两个方面解构了全球水政治关系,并从网络关系特征和空间演化特征两个方面厘清了全球水政治格局的动态变化趋势。结果显示：①国家（地区）间水冲突网络与水合作网络热点区域在空间上发生了明显位移,水冲突网络热点由中亚向南亚、东南亚转移,而南亚、东南亚地区亦逐渐成为水合作的热点区;②国家（地区）间水冲突网络与水合作网络均表现为显著的核心—边缘结构,各个圈层间存在明显的更迭过程;③国家（地区）间水政治关系网络社团分化明显,相较于国家（地区）间水冲突的社团集聚模式,国家（地区）间水合作网络社团结构更为紧密,地理邻近特征更显著;④根据国家（地区）间水政治关系值,可将水政治双边关系分为紧张关系、友好关系和相对和缓关系。美洲地区前期水政治友好关系突出,东南亚国家后期水政治友好互动频繁,中东地区水政治关系较为紧张。 相似文献
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《Information processing & management》2023,60(4):103399
Developing a tourism forecasting function in decision support systems has become critical for businesses and governments. The existing forecasting models considering spatial relations contain insufficient information, and the spatial aggregation of simple tourist volume series limits the forecasting accuracy. Using human-generated search engines and social media data has the potential to address this issue. In this paper, a spatial aggregation-based multimodal deep learning method for hourly attraction tourist volume forecasting is developed. The model first extracts the daily features of attractions from search engine data; then mines the spatial aggregation relationships in social media data and multi-attraction tourist volume data. Finally, the model fuses hourly features with daily features to make forecasting. The model is tested using a dataset containing several attractions with real-time tourist volume at 15-minute intervals from November 27, 2018, to March 18, 2019, in Beijing. And the empirical and Diebold-Mariano test results demonstrate that the proposed framework can outperform state-of-the-art baseline models with statistically significant improvements at the 1% level. Compared with the best baseline model, the MAPE values are reduced by 50.0% and 27.3% in 4A attractions and 5A attractions, respectively; and the RMSE values are reduced by 48.3% and 26.1%, respectively. The method in this paper can be used as a function embedded in the decision support system to help multi-department collaboration. 相似文献
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The fundamental idea of the work reported here is to extract index phrases from texts with the help of a single word concept dictionary and a thesaurus containing relations among concepts. The work is based on the fact, that, within every phrase, the single words the phrase is composed of are related in a certain well denned manner, the type of relations holding between concepts depending only on the concepts themselves. Therefore relations can be stored in a semantic network. The algorithm described extracts single word concepts from texts and combines them to phrases using the semantic relations between these concepts, which are stored in the network. The results obtained show that phrase extraction from texts by this semantic method is possible and offers many advantages over other (purely syntactic or statistic) methods concerning preciseness and completeness of the meaning representation of the text. But the results show, too, that some syntactic and morphologic “filtering” should be included for effectivity reasons. 相似文献
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研究了基于CityGML的多层次细节3D城市模型快速建模方法,并将其结合到3DUGIS中用于数字城市建设。建模过程中考虑空间关系、拓扑关系和语义信息,建模过程自动化程度高,能够在三维空间直接进行空间分析,方便海量数据的交换与数据挖掘。并给出了上海世博园区三维信息系统结合具体应用案例。 相似文献
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国土空间规划作为“多规合一”改革的重要成果,反映了生态文明建设的根本要求和转变国土空间治理方式的现实需要,其中有大量理论和实践问题需要深入研究。本文重点讨论了十个基本关系问题。其中,规划与市场、空间规划与发展规划两大关系,是国土空间规划的基本关系,处理好这两大关系,才能合理确定国土空间规划的功能定位和职责边界,保证“多规合一”改革的正确走向;高质量发展与高品质国土、集聚开发与均衡发展、新型城镇化与乡村振兴、新城开发与城市更新四大关系,是国土空间规划的时代主题和主要内容,处理好这四大关系,才能有效发挥国土空间规划的作用;“三区”划分与“三线”划定、规范化与特色化、政策创新与技术创新、规划编制与规划实施四大关系,是国土空间规划的方法论,处理好这四大关系,是科学编制和有效实施国土空间规划的前提和基础。 相似文献
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《Information processing & management》2003,39(4):543-559
In this paper, we present a new method to improve the performance of query processing in a spatial database. The previous approach can process the retrieval of spatial objects by topological relations using R-tree structures based on minimum bounding rectangles. In our approach, we add internal rectangle to the leaf nodes of the R-tree as additional information for helping objects retrieval. As a result, the number of false hits can be reduced and part of the true hits can be identified at the early stage of searching. The experiments demonstrated that the performance of database systems can be improved because both the number of objects accessed and the number of objects requiring detailed inspection are much less than those in the previous approach. 相似文献
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由于公众支付意愿（WTP）存在空间差异,以距离为依据,研究空间尺度下的CVM评价方法问题。通过构建WTP的空间滞后模型,结合Moran’s I指数和空间分割效应探讨WTP的空间作用关系,弥补了传统CVM模型在空间效应分析中的不足。针对二分式CVM数据是区间数据的特点,应用概率效用函数提出WTP空间滞后模型的参数估计方法。以松花江为例进行实证分析,结果表明：①WTP空间滞后模型能够有效处理空间尺度下的二分式CVM数据;②得到不同空间尺度下的WTP存在距离衰减效应,且公众认知程度是影响其衰减的主要动因;③得到2012年松花江生态价值为83.15亿元·年。研究结论为CVM评价生态资源环境价值提供新的途径,提高CVM评价结论的科学性及有效性,为相关环境经济政策的费用负担及利益分配提供参考依据。 相似文献