NS Seminar

Date and Location

Apr 20, 2018 - 1:00pm to 2:00pm
Bldg 434, room 122


Efficient snapshot retrieval over historical graph data (presented by Isaac Mackey, Computer Science)

Khurana, U., & Deshpande, A. (2013). Efficient snapshot retrieval over historical graph data. In Data Engineering (ICDE), 2013 IEEE 29th International Conference (pp. 997-1008).

We address the problem of managing historical data for large evolving information networks like social networks or citation networks, with the goal to enable temporal and evolutionary queries and analysis. We present the design and architecture of a distributed graph database system that stores the entire history of a network and provides support for efficient retrieval of multiple graphs from arbitrary time points in the past, in addition to maintaining the current state for ongoing updates. Our system exposes a general programmatic API to process and analyze the retrieved snapshots. We introduce DeltaGraph, a novel, extensible, highly tunable, and distributed hierarchical index structure that enables compactly recording the historical information, and that supports efficient retrieval of historical graph snapshots for single-site or parallel processing.


Dynamic Network Embedding by Modeling Triadic Closure Process (presented by Furkan Kocayusufoglu, Computer Science)

Zhou, L., Yang, Y., Ren, X., Wu, F., & Zhuang, Y. (2018). Dynamic Network Embedding by Modeling Triadic Closure Process.

Network embedding, which aims to learn the low dimensional representations of vertices, is an important task and has attracted considerable research efforts recently. In real world, networks, like social network and biological networks, are dynamic and evolving over time. However, almost all the existing network embedding methods focus on static networks while ignore network dynamics.

In this paper, we present a novel representation learning approach, DynamicTriad, to preserve both structural information and evolution patterns of a given network. The general idea of our approach is to impose triad, which is a group of three vertices and is one of the basic units of networks. In particular, we model how a closed triad, which consists of three vertices connected with each other, develops from an open triad that has two of three vertices not connected with each other. This triadic closure process is a fundamental mechanism in the formation and evolution of networks, thereby makes our model being able to capture the network dynamics and to learn representation vectors for each vertex at different time steps.

Experimental results on three real-world networks demonstrate that, compared with several state-of-the-art techniques, DynamicTriad achieves substantial gains in several application scenarios. For example, our approach can effectively be applied and help to identify telephone frauds in a mobile network, and to predict whether a user will repay her loans or not in a loan network.