Recent Projects


Information Diffusion and Opinion Formation in Networked Systems. This is a collaborative project with Profs. Kartik Hosanagar (Penn, Wharton Business School), Santosh Venkatesh (Penn, ESE department), and Yong Tan (U. Washington, Business School). The project was supported by NSF grant CCF-1137519 and sought to explore opinion formation and (product) adoption decisions in (social) networks.

The project involved three complementary efforts. The first targeted an empirical investigation of opinion formation in social networks, the second dealt with the development of analytical models to study opinion formation in networks, and the third consisted of an investigation of adoption of competing products that exhibit strong network effects.

The goal of the empirical study is to construct a predictive statistical framework to investigate the mechanisms of opinion formation and evolution in online communities where social interactions take place.

The development of analytical models of opinion formation assumes that individuals could be influenced by their network peers, and more importantly that the weights of those influences are biased based on an individual’s party affiliation. This is motivated by an interest in how external structures such as parties play a role in shaping the evolution of (networked) opinions.

The topic of adoption of competing (network) products is aimed at understanding how connections between network users (the network topology) affect their decision to adopt either one or both of two competing products. Product adoption depends on the stand-alone quality of the products (how good they are) and their user base (a social network is more attractive once all my friends are on it).


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Exploring the Challenges of Network Migration - An IPv6 Case Study and its Consequences. This is a joint project initiated with Comcast and supported by NSF grant CNS-1116039. Its goals are were to assess, understand, and encourage the adoption of IPv6. Specifically, as we were rapidly approach the date at which the current set of IPv4 addresses will have been exhausted, i.e., in 2011, migrating to IPv6 was becoming increasingly important. This migration is, however, largely dependent on ensuring that the current IPv4 Internet, and in particular its content, becomes itself accessible over IPv6. Tracking the extent to which this is happening is the main purpose of this project. This tracking is performed by a monitoring client that queries the Domain Name System (DNS) for IPv4 and IPv6 addresses (A and quad-A records) for a number of known sites. The list of sites queried includes the top one million (1M) web sites according to the ranking maintained by Alexa, and possibly additional sites beyond the top 1M (the monitoring system currently tracks the Ipv6 accessibility of over 6M web sites, including Alexa's top 1M).


Content is deemed IPv6 accessible if DNS returns a quad-A record for the site. Sites identified as being both IPv4 and IPv6 accessible are then queried for content, and deemed IPv4 and IPv6 reachable if the same content can be retrieved over both. The relative performance of content retrieval over IPv4 and IPv6 is then compared based on a succession of queries. One of the project's goals is to analyze this data to understand when, where and why differences exist between Ipv4 and IPv6 access, and how these should be addressed or used to foster a faster a migration to IPv6. In addition, in order to provide a more comprehensive perspective on the level of IPv6 adoption across the Internet, the monitoring software is being deployed at multiple locations. The goal is to ultimately make the information gathered across locations publicly available to facilitate research and evaluation by others.

Project Website

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On the Economic Viability of Network Architectures. This was a joint project with Prof. Kartik Hosanagar from the Wharton Business School and Profs. Andrew Odlyzko and Zhi-Li Zhang from the University of Minnesota, which was funded by NSF under the FIND initiative (NSF grant CNS-0721610). The project had three main thrust areas aimed at assessing the economic viability of new network architectures:


  1. Investigate and quantify the potential benefits of key proposed architectural features such as virtualization, integration, and diversity;

  2. Explore when and why the existence of a formidable incumbent (today’s Internet) can affect the emergence of new technologies;

  3. Develop models that account for how the openness and flexibility of a network architecture can foster the adoption of new technology, and its ultimate success.

Project Website

Related Publications