Thursday, September 30, 2021

Thursday, September 30, 2021 — 10:00 to 10:00 AM EDT

Title: Semidefinite Optimization Approaches for Reactive Optimal Power Flow Problems

Speaker: Miguel Anjos Affiliation: University of Edinburgh Zoom: Register through The Fields Institute

Abstract:

The Reactive Optimal Power Flow (ROPF) problem consists in computing an optimal power generation dispatch for an alternating current transmission network that respects power flow equations and operational constraints. Some means of voltage control are modelled in ROPF such as the possible activation of shunts, and these controls are modelled using discrete variables. The ROPF problem belongs to the class of nonconvex MINLPs, which are NP-hard problems. We consider semidefinite optimization approaches for solving ROPF problems and their integration into a branch-and-bound algorithm.

Thursday, September 30, 2021 — 11:00 to 11:00 AM EDT

Title: Structured (In)Feasibility: Nonmonotone Operator Splitting in Nonlinear Spaces

Speaker: Bissan Ghaddar Affiliation: Western University Zoom: Register through The Fields Institute

Abstract:

Several challenging optimization problems in power networks involve operational decisions, non-linear models of the underlying physics described by the network as well as uncertainty in the system parameters. However, these networks exhibit a nice structure. This talk provides an overview of approaches that combine recent advances in robust optimization and conic relaxations of polynomial optimization problems along with exploiting the structure of the underlying problem. These approaches are demonstrated on applications arising in power networks.

Thursday, September 30, 2021 — 1:00 PM EDT

Title: Forcing Quasirandomness in Permutations

Speaker: John Noel Affiliation: University of Victoria Zoom: Contact Steve Melczer

Abstract:

A striking result in graph theory is that the property of a graph being quasirandom (i.e. resembling a random graph) is characterized by the number of edges and the number of 4-cycles being close to the expected number in a random graph. Král’ and Pikhurko (2013) proved an analogous result for permutations; i.e. that quasirandom permutations are characterized by the densities of all permutations of length 4.

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