network science

Optimal resource allocation for remediating networked contagions

Dynamic interventions for networked contagions

We study the problem of designing dynamic intervention policies for minimizing networked defaults in financial networks. Formally, we consider a dynamic version of the celebrated Eisenberg-Noe model of financial network liabilities and use this to …

Online Collaborative-Filtering on Graphs

A common phenomena in modern recommendation systems is the use of feedback from one user to infer the 'value' of an item to other users. This results in an exploration vs. exploitation trade-off, in which items of possibly low value have to be …

Personalized pagerank estimation and search: A bidirectional approach

We present new algorithms for Personalized PageRank estimation and Personalized PageRank search. First, for the problem of estimating Personalized PageRank (PPR) from a source distribution to a target node, we present a new bidirectional estimator …

Bidirectional PageRank Estimation: From Average-Case to Worst-Case

We present a new algorithm for estimating the Personalized PageRank (PPR) between a source and target node on undirected graphs, with sublinear running-time guarantees over the worst-case choice of source and target nodes. Our work builds on a recent …

Fast Bidirectional Probability Estimation in Markov Models

We develop a new bidirectional algorithm for estimating Markov chain multi-step transition probabilities: given a Markov chain, we want to estimate the probability of hitting a given target state in $\ell$ steps after starting from a given source …

Epidemic Spreading With External Agents

We study epidemic spreading processes in large networks, when the spread is assisted by a small number of external agents: infection sources with bounded spreading power, but whose movement is unrestricted vis-a-vis the underlying network topology. …

FAST-PPR: scaling personalized pagerank estimation for large graphs

We propose a new algorithm, FAST-PPR, for estimating personalized PageRank: given start node $s$ and target node $t$ in a directed graph, and given a threshold $\delta$, FAST-PPR estimates the Personalized PageRank $\pi_s(t)$ from $s$ to $t$, …

The behavior of epidemics under bounded susceptibility

We investigate the sensitivity of epidemic behavior to a bounded susceptibility constraint -- susceptible nodes are infected by their neighbors via the regular SI/SIS dynamics, but subject to a cap on the infection rate. Such a constraint is …

Epidemic thresholds with external agents