Week of Events
Estimating the physical location of Twitter users with the von Mises-Fisher distribution (Mike Izbicki, UC Riverside)
Estimating the physical location of Twitter users with the von Mises-Fisher distribution (Mike Izbicki, UC Riverside)
Approximately 500 million tweets are sent everyday. Scientists monitor these tweets to predict the spread of disease, better allocate social welfare services, help first responders during natural disasters, and many other important tasks. A key step in each of these tasks is estimating the location the tweet was sent from. In this talk, I discuss how to combine machine […]
Lattices from group frames and vertex transitive graphs (Lenny Fukshansky, CMC)
Lattices from group frames and vertex transitive graphs (Lenny Fukshansky, CMC)
Tight frames in Euclidean spaces are widely used convenient generalizations of orthonormal bases. A particularly nice class of such frames is generated as orbits under irreducible actions of finite groups of orthogonal matrices: these are called irreducible group frames. Integer spans of rational irreducible group frames form Euclidean lattices with some very nice geometric properties, […]
Algebraic and Polyhedral Perspectives on Combinatorial Neural Codes (Robert Davis, Harvey Mudd)
Algebraic and Polyhedral Perspectives on Combinatorial Neural Codes (Robert Davis, Harvey Mudd)
In the 1970s, James O’Keefe and his team observed that certain neurons in the brain, called place cells, spike in their firing rates when the animal is in a particular physical location within its arena. If a place cell is thought of as either “active” or “silent,” then one may represent the co-firing patterns of […]