Software systems produce long sequences of call graphs, in particular, if the graphs are generated during runtime and not revision by revision. Visualizing, analyzing, and interacting with such long dynamic graphs with respect to different properties is a challenging task. In this article we describe an interactive visualization technique for dynamic call graphs that supports the observation of the data in vertex, edge, and time dimensions based on properties related to the graph topology, inherent vertex hierarchy, involved links, and graph-theoretic problems. Moreover, we provide a time-aligned view on several dynamic graphs with the goal to compare them visually. We also provide standard node-link diagrams for individual graphs or aggregated dynamic graph subsequences as a details-on-demand technique and for supporting graph comparisons on different temporal granularities. We illustrate the usefulness of the dynamic graph visualization by applying it to the call relations at runtime of the open source software project JHotDraw. We evaluated the interactive visualization by reflecting on the static and dynamic patterns we could identify in the dataset by changing the graph properties under exploration. Moreover, we conducted a controlled user study with 20 participants investigating three typical tasks like finding graph sequences, identifying a complete graph, and exploring the reason for a change in a shortest path algorithm. Finally, we discuss scalabilities and limitations of our approach.

软件系统会生成较长的调用图序列，特别是如果这些图是在运行时生成的，而不是逐个修订的。可视化，分析并与如此长的动态图进行交互以具有不同的特性，这是一项艰巨的任务。在本文中，我们描述了一种用于动态调用图的交互式可视化技术，该技术基于与图拓扑，固有顶点层次结构，所涉及的链接和图论问题相关的属性，支持在顶点，边沿和时间维度上观察数据。此外，我们在几个动态图上提供了时间对齐的视图，目的是在视觉上进行比较。我们还为单个图或聚合的动态图子序列提供标准的节点链接图，作为按需详细信息技术，并支持在不同时间粒度上进行图比较。我们通过在开源软件项目JHotDraw的运行时将其应用于调用关系来说明动态图可视化的有用性。我们通过思考可以通过更改正在探索的图形属性在数据集中识别的静态和动态模式来评估交互式可视化。此外，我们与20名参与者进行了一项受控用户研究，研究了三个典型任务，例如查找图序列，识别完整图以及探索最短路径算法发生变化的原因。最后，我们讨论了方法的可扩展性和局限性。