• Publications
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Speeding up the Xbox recommender system using a euclidean transformation for inner-product spaces
A prominent approach in collaborative filtering based recommender systems is using dimensionality reduction (matrix factorization) techniques to map users and items into low-dimensional vectors. Expand
How To Grade a Test Without Knowing the Answers - A Bayesian Graphical Model for Adaptive Crowdsourcing and Aptitude Testing
We propose a new probabilistic graphical model that jointly models the difficulties of questions, the abilities of participants and the correct answers to questions in aptitude testing and crowdsourcing settings. Expand
Personality and patterns of Facebook usage
We show how users' activity on Facebook relates to their personality, as measured by the standard Five Factor Model. Expand
Approximating power indices: theoretical and empirical analysis
We suggest and analyze randomized methods to approximate power indices such as the Banzhaf power index and the Shapley–Shubik power index. Expand
Studying User Income through Language, Behaviour and Affect in Social Media
Automatically inferring user demographics from social media posts is useful for both social science research and a range of downstream applications in marketing and politics. We present the firstExpand
Divide and conquer: false-name manipulations in weighted voting games
In this paper, we study false-name manipulations in weighted voting games. Weighted voting is a well-known model of cooperation among agents in decision-making domains. In such games, each of theExpand
Open-ended Learning in Symmetric Zero-sum Games
We introduce a geometric framework for formulating agent objectives in zero-sum games, in order to construct adaptive sequences of objectives that yield open-ended learning. Expand
Bitcoin Mining Pools: A Cooperative Game Theoretic Analysis
We examine dynamics of pooled mining and the rewards that pools manage to collect, and use cooperative game theoretic tools to analyze how pool members may share these rewards. Expand
The Cost of Stability in Coalitional Games
A key question in cooperative game theory is that of coalitional stability, usually captured by the notion of the core --the set of outcomes such that no subgroup of players has an incentive to deviate. Expand
Approximating power indices
The height of a continuous tobacco stream between a first side which is supported by a conveyor and an uneven second side is monitored by an opto-electrical level detector which directs a row of parallel light rays transversely across the stream and has a battery of photosensitive elements. Expand