Solving the mystery of vanishing rivers in China

A major controversy was sparked worldwide by a recent national water census claiming that the number of Chinese rivers with watersheds ≥100 km² was less than half the previous estimate of 50 000 rivers, which also stimulates debates on the potential causes and consequences. Here, we estimated the number of rivers in terms of stream-segmentation characteristics described by Horton, Strahler and Shreve stream-order rules, as well as their mixed mode for named rivers recorded in the Encyclopedia of Rivers and Lakes in China. As a result, the number of ‘vanishing rivers’ has been found to be highly relevant to statistical specifications in addition to the erroneous inclusion of pseudo-rivers primarily generated in arid or frost-thaw areas. The modified Horton stream-order scheme reasonably depicts the configuration of complete natural streams from headwater to destination, while the Strahler largely projects the fragmentation of the named river networks associated with human aggregation to the hierarchical river systems.     

Arts audience segmentation: data,profiles, segments and biographies

ABSTRACT

This article critically examines how segmentation is used to identify, understand and engage arts audiences. Policy reports and academic publications are reviewed to establish the priorities of arts policymakers and practitioners for understanding arts audiences and their continued focus on audience data and segmentation. This article then makes two contributions. Firstly, critical perspectives on the use of data for audience profiling are applied to arts audience segmentation. Secondly, research using biographical methods is introduced as a new approach for critically evaluating arts audience segmentation. This research, employing biographical methods, shows the exploration and negotiation of audience identity positions. This article takes these insights to critically examine the implications of how profiles and segments are used to define and understand audiences for the arts. The conclusion addresses the implications of segmentation in terms of the design and communication of cultural experiences, the complexities of aligning audiences’ identities with segments, and the seemingly inevitability of exclusion. This article will be of relevance in the scholarly study of arts audiences and for arts and cultural organisations and policymakers in reflecting on the implications of quantitative and qualitative approaches in designing and undertaking audience research.     

智能交通领域中机动车牌照自动识别技术研究

对车牌图像预处理和字符识别做了系统的阐述,针对字符分割采用了一种基于投影变换的分割算法,并就字符特征向量提取及字符识别方法进行了描述,设计了一种机动车牌照自动识别系统的解决方案。     

基于RUS-CHN标准的手腕骨骨化中心识别分割算法

摘要：骨龄是儿童青少年生长发育的重要指标,目前自动化骨龄判读算法研究中,针对骨化中心的准确分割提取是重要一环。然而之前的研究多采用单一算法、过度追求算法效率,导致稳定性、准确度不高。本研究基于《中国人手腕骨发育标准-中华05》中RUS-CHN方法,针对13处骨化中心的提取问题,改进了骨化中心提取的准确度和稳定性。所用算法包括： Canny边缘识别、基于局部图像灰度特征的边缘筛选,边缘连接、骨中轴线多项式拟合、基于Gabor纹理分析的骨化中心精确定位算法。实验表明：对随机抽样的980张待分割样本,本研究应用综合算删除法,对RUS-CHN判读方法所关注的13个骨化中心区域进行分割,13个骨化中心均正确识别并分割的成功率达到了99.2%。     

基于阈值优先分割的光通信网络冲突解决方法

针对光通信网络中不同优先级业务突发冲突问题,导致数据服务质量差与丢包率高的问题,提出一种基于阈值优先分割的光通信网络冲突解决方法,该方法根据阈值分割准则来控制偏射路径,当不同优先级数据包冲突时,首先分割优先级较低的数据包进行偏射,然后根据阈值优先分割准则在冲突路由节点寻找最优路径,最后将冲突数据包通过预置或空闲路径传输,使得不同优先级业务数据包分配更加合理,最大限度地降低了由突发冲突引起的高阻塞率与丢包率。仿真结果表明,该方法可以有效降低总丢包率并保证其服务质量,且网络延时较小,从而改善整个OBS网络的服务质量性能。     

网络教育服务中的客户细分策略分析

随着终身学习理念的深入人心,网络教育服务市场前景会更加广阔,同时竞争也在加剧。对客户进行细分,提供有针对性的营销策略、服务模式将有助于提高网络教育服务机构市场竞争力。从客户终身价值、学习者媒介偏好、利益细分等角度分析网络教育服务中的客户细分策略。     

谢无量《中国大文学史》得失论

谢无量的《中国大文学史》是一部得失兼具的早期文学史论著。该书内容丰富、分期合理、材料翔实,充分体现了文学史编写内容由宽而泛向纯而专过渡的积极意义;但也明显存在着结构有失均衡,资料引证过繁,未能谨守“纯文学观”而出现的偏颇。     

基于多尺度小波的城市遥感图像纹理特征提取

遥感技术为人们提供了大量的图像数据,如何从中提取所需信息,是遥感图像处理技术研究的热点。基于多尺度小波变换,可提取城市图像的纹理特征。根据城市影像中地物特征和小波技术的特点,确定合适的窗口大小,采用逐一滑动窗口的方法,对每一窗口提取相应的小波统计特征;应用小波变换的多尺度特性,在不同尺度上提取出子图像特征,构造出纹理特征矢量,为遥感图像的分类提供纹理特征。     

SVM for density estimation and application to medical image segmentation

A method of medical image segmentation based on support vector machine （SVM） for density estimation is presented. We used this estimator to construct a prior model of the image intensity and curvature profile of the structure from training images. When segmenting a novel image similar to the training images, the technique of narrow level set method is used. The higher dimensional surface evolution metric is defined by the prior model instead of by energy minimization function. This method offers several advantages. First, SVM for density estimation is consistent and its solution is sparse. Second, compared to the traditional level set methods, this method incorporates shape information on the object to be segmented into the segmentation process. Segmentation results are demonstrated on synthetic images, MR images and ultrasonic images.     

Collection-based compound noun segmentation for Korean information retrieval

Compound noun segmentation is a key first step in language processing for Korean. Thus far, most approaches require some form of human supervision, such as pre-existing dictionaries, segmented compound nouns, or heuristic rules. As a result, they suffer from the unknown word problem, which can be overcome by unsupervised approaches. However, previous unsupervised methods normally do not consider all possible segmentation candidates, and/or rely on character-based segmentation clues such as bi-grams or all-length n-grams. So, they are prone to falling into a local solution. To overcome the problem, this paper proposes an unsupervised segmentation algorithm that searches the most likely segmentation result from all possible segmentation candidates using a word-based segmentation context. As word-based segmentation clues, a dictionary is automatically generated from a corpus. Experiments using three test collections show that our segmentation algorithm is successfully applied to Korean information retrieval, improving a dictionary-based longest-matching algorithm.