可控阵幂敛指数的一个新上界

从局部幂敛指数出发，对局部幂敛指数与其有向图的结构之间的关系进行了细致的分析，得到了1个简单易行的判断可控阵幂敛指数上界的方法，给出了可控阵幂敛指数的1个新的上界。     

关于图的强Helly性质

给出图的点团二分图和边团二分图具有强Helly性质的充分必要条件,证明了使点团二分图具有强Helly性质的图的团贪心性和团不变性。     

An analytical method of stage–fall–discharge rating

This paper presents an analytical method for establishing a stage–fall–discharge rating using hydraulic performance graphs (HPG). The rating curves derived from the HPG are used as the basis to establish the functional relation of stage, fall and discharge through regression analysis following the USGS procedure. In doing so, the conventional trial‐and‐error process can be avoided and the associated uncertainties involved may be reduced. For illustration, the proposed analytical method is applied to establish stage–fall–discharge relations for the Keelung River in northern Taiwan to examine its accuracy and applicability in an actual river. Based on the data extracted from the HPG for the Keelung River, one can establish a stage–fall–discharge relation that is more accurate than the one obtained by the conventionally used relation. Furthermore, the discharges obtained from the proposed rating method are verified through backwater analysis for measured high water level events. The results indicate that the analytical stage–fall–discharge rating method is capable of circumventing the shortcomings of those based on single‐station data and, consequently, enhancing the reliability of flood estimation and forecasting. Copyright © 2008 John Wiley & Sons, Ltd.     

基于知识图谱的增强型混合式学习的教学实践与思考

随着互联网与信息技术的快速发展,线上线下混合式学习逐渐得到普及与应用。混合式学习强调学生的主体作用,注重学生的自主学习、协作学习和个性化学习,是良好的适合高等教育的创造性学习模式。但是在目前的混合式学习模式下,学生对知识的加工、梳理、整合能力不够,构建完整知识体系的自主学习能力稍显薄弱,因此亟需更多引导。文章综合分析了混合式学习模式的优缺点,建议引入人工智能领域的知识图谱概念,作为新的教学元素以引导和加强学生的自主学习过程,由此构建了基于知识图谱的增强型混合式学习模式。该模式在2020年南京大学《古无脊椎动物学》课程中进行了实践,进一步证明其在改善学生自主学习能力方面的潜力。     

Construction of a fluvial facies knowledge graph and its application in sedimentary facies identification

Lithofacies paleogeography is a data-intensive discipline that involves the interpretation and compilation of sedimentary facies. Traditional sedimentary facies analysis is a labor-intensive task with the added complexity of using unstructured knowledge and unstandardized terminology. Therefore, it is very difficult for beginners or non-geology scholars who lack a systematic knowledge and experience in sedimentary facies analysis. These hurdles could be partly alleviated by having a standardized, structured, and systematic knowledge base coupled with an efficient automatic machine-assisted sedimentary facies identification system. To this end, this study constructed a knowledge system for fluvial facies and carried out knowledge representation. Components include a domain knowledge graph for types of fluvial facies (meandering, braided and other fluvial depositional environments) and their characteristic features (bedforms, grain size distribution, etc.) with visualization, a method for query and retrieval on a graph database platform, a hierarchical knowledge tree-structure, a data-mining clustering algorithm for machine-analysis of publication texts, and an algorithm model for this area of sedimentary facies reasoning. The underlying sedimentary facies identification and knowledge reasoning system is based on expert experience and synthesis of publications. For testing, 17 sets literature publications data that included details of sedimentary facies data (bedforms, grain sizes, etc.) were submitted to the artificial intelligence model, then compared and validated. This testing set of automated reasoning results yielded an interpretation accuracy of about 90% relative to the published interpretations in those papers. Therefore, the model and algorithm provide an efficient and automated reasoning technology, which provides a new approach and route for the rapid and intelligent identification of other types of sedimentary facies from literature data or direct use in the field.     

基于边缘图与边缘方向的遥感图像检索

本文在系统介绍遥感图像检索中边缘特征描述方法的基础上,将边缘特征归纳为边缘图和边缘方向两类特征。通过对遥感目标图像库和纹理图像库上所做实验的分析,揭示了不同算法的特性,并指出综合两类特征可进一步提高算法的检索性能。     

平切图大坝地质三维建模及剖切分析

利用剖面图进行地质体建模因其复杂度很高,常常是利用CAD或类似的地质建模软件进行交互式的建模,因此非常耗时。本文以大坝地质平切图(剖面图的一种)为数据源,开发了一种"多段连接"的方法可以自动构建地质体的三维表面模型,以及一种"三次搜索法"用于模型剖切分析,并在实际项目中验证了本文方案的有效性。     

四叉树结构在数字图像分割中的应用

本文讨论了四叉树的基本概念、图像的四叉树表示以及四叉树结构在计算机中的实现；给出了用这种算法实现分裂与合并算法的步骤。实验表明，把四叉树结构引入图像分割，收到了较好的效果。     

地形图线状目标与点状符号的自动分离

提出一种新的图文分离方法．该方法在字符与线划粘连、存在虚线等情况下均能取得满意效果．