Changhyun Lee

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Twitter, a microblogging service less than three years old, commands more than 41 million users as of July 2009 and is growing fast. Twitter users tweet about any topic within the 140-character limit and follow others to receive their tweets. The goal of this paper is to study the topological characteristics of Twitter and its power as a new medium of(More)
Topic modeling has been widely used for analyzing text document collections. Recently, there have been significant advancements in various topic modeling techniques, particularly in the form of probabilistic graphical modeling. State-of-the-art techniques such as Latent Dirichlet Allocation (LDA) have been successfully applied in visual text analytics.(More)
Twitter offers an explicit mechanism to facilitate information diffusion and has emerged as a new medium for communication. Many approaches to find influentials have been proposed, but they do not consider the temporal order of information adoption. In this work, we propose a novel method to find influentials by considering both the link structure and the(More)
The nature of congestion feedback largely governs the behavior of congestion control. In datacenter networks, where RTTs are in hundreds of microseconds, accurate feedback is crucial to achieve both high utilization and low queueing delay. Proposals for datacenter congestion control predominantly leverage ECN or even explicit innetwork feedback (e.g.,(More)
A main bottleneck in integrating computational methods with visual analytics is their significant computational cost, which hinders real-time interactive visualization with them. To solve this, we present PIVE (Per-Iteration Visualization Environment), which visualizes intermediate results from algorithm iterations, thus allowing users to efficiently(More)
Non-profit Micro-finance organizations provide loaning opportunities to eradicate poverty by financially equipping impoverished, yet skilled entrepreneurs who are in desperate need of an institution that lends to those who have little. Kiva.org, a widely-used crowd-funded micro-financial service, provides researchers with an extensive amount of publicly(More)
Many measurement systems have been proposed in recent years to shed light on the internal performance of the Internet. Their common goal is to allow distributed applications to improve end-user experience. A common hurdle they face is the need to deploy yet another measurement infrastructure. In this work, we demonstrate that without any new measurement(More)
1389-1286/$ see front matter 2010 Elsevier B.V doi:10.1016/j.comnet.2010.10.004 ⇑ Corresponding authors. Tel.: +82 42 350 3588; f E-mail addresses: dklee@an.kaist.ac.kr (DK Lee ac.kr (K. Jang), chlee@an.kaist.ac.kr (C. Lee), gianlu com (G. Iannaccone), sbmoon@kaist.edu (S. Moon). Internet-wide services and applications depend on accurate information about(More)