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Global Solution Strategies for the Network-Constrained Unit Commitment Problem with AC Transmission Constraints

IEEE Transactions on Power Systems

Castillo, Anya; Watson, Jean-Paul W.; Laird, Carl D.

We propose a novel global solution algorithm for the network-constrained unit commitment problem that incorporates a nonlinear alternating current (ac) model of the transmission network, which is a nonconvex mixed-integer nonlinear programming problem. Our algorithm is based on the multi-tree global optimization methodology, which iterates between a mixed-integer lower-bounding problem and a nonlinear upper-bounding problem. We exploit the mathematical structure of the unit commitment problem with ac power flow constraints and leverage second-order cone relaxations, piecewise outer approximations, and optimization-based bounds tightening to provide a globally optimal solution at convergence. Numerical results on four benchmark problems illustrate the effectiveness of our algorithm, both in terms of convergence rate and solution quality.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

Small scale to extreme: Methods for characterizing energy efficiency in supercomputing applications

Sustainable Computing: Informatics and Systems

Younge, Andrew J.

Power measurement capabilities are becoming commonplace on large scale HPC system deployments. There exist several different approaches to providing power measurements that are used today, primarily in-band and out-of-band measurements. Both of these fundamental techniques can be augmented with application-level profiling and the combination of different techniques is also possible. However, it can be difficult to assess the type and detail of measurement needed to obtain insights and knowledge of the power profile of an application. In addition, the heterogeneity of modern hybrid supercomputing platforms requires that different CPU architectures must be examined as well. This paper presents a taxonomy for classifying power profiling techniques on modern HPC platforms. Three relevant HPC mini-applications are analyzed across systems of multicore and manycore nodes to examine the level of detail, scope, and complexity of these power profiles. We demonstrate that a combination of out-of-band measurement with in-band application region profiling can provide an accurate, detailed view of power usage without introducing overhead. Furthermore, we confirm the energy and power profile of these mini applications at an extreme scale with the Trinity supercomputer. This finding validates the extrapolation of the power profiling techniques from testbed scale of just several dozen nodes to extreme scale Petaflops supercomputing systems, along with providing a set of recommendations on how to best profile future HPC workloads.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus
Results 2351–2400 of 9,998
Results 2351–2400 of 9,998