中文摘要：

词云是一种典型的用于文本分析的可视化形式,更美观的可视化效果和更佳的实用性是研究者们研究的主题.针对边界约束下语义聚集的词云在单词发生改变时的紧凑布局和单词间拓扑结构保持的问题,提出一种适用于元组确定式文本的词云布局方式,在确定元组数目的基础上,用Power图剖分显示界面,利用单词间的属性依赖实现词云的初始布局;然后提出边界约束词云的拓扑保持算法,定义了5种约束规则、单词间相对约束力以及边界约束力,规定了词云在布局过程中的约束条件,以保证词云拓扑保持的同时实现单词在确定边界下的无重叠布局.针对词云的不同边界形状详细定义边界约束力,并分别对不同形状的词云进行局部单词放大、删除、缩小实验,结果显示,文中的拓扑保持算法在词云内单词发生变化时较好地保证视觉效果,同时有效地保持了原有的拓扑结构.

英文摘要：

As a classical visualization tool for text analysis, the word cloud has received many attentions. However,the word cloud with bounded constraint may be unstable when words changed. To solve this problem, thispaper first proposes a word cloud layout method for certain amount of words. The method uses the Power diagramto divide the space into certain areas. Thereafter, the words are placed into different areas according to theirattributes initially. Then this paper adopts five kinds of constraint rules, a relative force between words and aboundary force. These rules and forces help preserve the topology in bounded constraint word clouds. Finally, thispaper defines the boundary forces for different shaped boundaries respectively. Furthermore, the experiment resultsshow that the final topology of the word cloud is similar with the original one, when we increase or decreasethe size of words or even delete the words in the word cloud.