ATD: Collaborative Research: Real-Time Network Pattern Change Detection

互联网上迅速增长的大量社交网络数据为理解人类行为提供了大量信息。首先，网络数据包含稀疏的通信频率和一些密集的聚类，并且聚类随着时间的推移而变化，因此特征生成和选择是必不可少的。该研究项目解决了检测网络中突然类别变化的统计挑战。这对于量化人类动态和准确识别异常事件并预测这些事件所表示的未来威胁非常重要。研究生将参与该项目的某些方面。该项目旨在开发1）对于静态情况：我们将使用零膨胀或障碍模型来表征类链接概率。2)对于类间通信概率随时间变化的动态情形，我们用自激过程来描述类间通信概率。3)我们考虑冷启动问题，其中预测网络与训练网络有很大差异，因此没有足够的样本来训练分类模型。相反，我们将开发矩阵变量聚类和分类模型。该项目包括几个重要的主题，以改善网络用户的类别建模和有效地识别突然的网络模式变化在真实的时间，以及减少离群值的影响。这些方法适用于各种类型的网络数据，如社交网络，生物信号，基因组序列等。PI将提供一个公开的软件包来实现所提出的方法。此外，相应的统计理论和计算技术可以扩展到推进进一步的研究，并可以应用到其他领域。这个项目的主题是为了满足学生在中央佛罗里达大学新的大数据分析项目的实践研究。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

The rapidly booming amounts of social networks data from the Internet offers a lot of information to understand human behaviors. First, the networks data contains sparse communication frequencies and some dense clusters, and the clusters change over time, so that feature generation and selection are essential. This research project addresses the statistical challenges for detecting abrupt categories changes in networks. This is important for quantifying human dynamics and accurately identifying unusual events and forecast future threats indicated by those events. Graduate students will be involved in some aspects of the project.This project aims to develop 1) for the static case: we will use zero-inflated or hurdle models to characterize the class link probability. 2) for the dynamic case: the class communication probability is a variable of time, we model the probability by a self-exciting process. 3) we consider the cold-start problem in which the predicted networks vary a lot from the training network, so that there are no enough samples to train classification models. Instead, we will develop matrix-variate clustering and classification models. This project includes several important topics to improve modeling of the network users' categories and identifying efficiently abrupt network pattern changes in real time as well as reducing the influence of outliers. These methods are applicable to various types of networks data such as social networks, biology signals, genome sequences, and so on. The PIs will provide a publicly-available software packages to implement the proposed methods. Additionally, corresponding statistical theories and computational techniques can be extended to advance further research and can be applied to other fields. This project topics cater to the students with hands-on studies in new Big-Data analysis program at the University of Central Florida.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.