Han Hee Song

Learn More
Overlay network monitoring enables distributed Internet applications to detect and recover from path outages and periods of degraded performance within seconds. For an overlay network with <i>n</i> end hosts, existing systems either require <i>O</i>(<i>n</i><sup>2</sup>) measurements, and thus lack scalability, or can only estimate the latency but not(More)
Disruption tolerant networks (DTNs) are a class of networks in which no contemporaneous path may exist between the source and destination at a given time. In such a network, routing takes place with the help of relay nodes and in a store-and-forward fashion. If the nodes in a DTN are controlled by rational entities, such as people or organizations, the(More)
In this paper, we present NetQuest, a flexible framework for large-scale network measurement. We apply <i>Bayesian experimental design</i> to select active measurements that maximize the amount of information we gain about the network path properties subject to given resource constraints. We then apply <i>network inference</i> techniques to reconstruct the(More)
Proximity measures quantify the closeness or similarity between nodes in a social network and form the basis of a range of applications in social sciences, business, information technology, computer networks, and cyber security. It is challenging to estimate proximity measures in online social networks due to their massive scale (with millions of users) and(More)
Overlay network monitoring enables distributed Internet applications to detect and recover from path outages and periods of degraded performance within seconds. For an overlay network with <i>n</i> end hosts, existing systems either require <i>O</i>(<i>n</i><sup>2</sup>) measurements, and thus lack scalability, or can only estimate the latency but not(More)
Measuring real-time end-to-end network path performance metrics is important for several distributed applications such as media streaming systems (e.g., for switching to paths with higher bandwidth and lower jitter) and content distribution systems (e.g., for selecting servers with lower latency). However, it is challenging to perform such end-to-end(More)
Users today access a multitude of online services---among the most popular of which are online social networks (OSNs)---via both web sites and dedicated mobile applications (apps), using a range of devices (traditional PCs, tablets, and smartphones) that are connected via a variety of networks. The resulting infrastructure makes these services conveniently(More)
Networks continue to change to support new applications, improve reliability and performance and reduce the operational cost. The changes are made to the network in the form of upgrades such as software or hardware upgrades, new network or service features and network configuration changes. It is crucial to monitor the network when upgrades are made because(More)
In large-scale IPTV systems, it is essential to maintain high service quality while providing a wider variety of service features than typical traditional TV. Thus service quality assessment systems are of paramount importance as they monitor the user-perceived service quality and alert when issues occurs. For IPTV systems, however, there is no simple(More)
With the proliferation of online social networking (OSN) and mobile devices, preserving user privacy has become a great challenge. While prior studies have directly focused on OSN services, we call attention to the privacy leakage in <i>mobile network data</i>. This concern is motivated by two factors. First, the prevalence of OSN usage leaves identifiable(More)