Computational Science

CSRC Colloquium - Prasanna Balaprakash
2023-04-07 15:30 - 16:30 UTC | Virtual Zoom Seminar
Title: Democratizing Deep Learning Development with DeepHyper
Abstract: In recent years, deep neural networks (DNNs) have achieved considerable success in learning complex nonlinear relationships between features and targets from large datasets. Nevertheless, designing high-performing DNN architecture for a given data set is an expert-driven, time-consuming, trial-and-error manual task. A major bottleneck in the construction of DNNs is the vast search space of architectures that need to be explored in the face of new data sets. Moreover, DNNs typically require user-specified values for hyperparameters, which strongly influence performance factors such as training time and prediction accuracy. In this talk, we will introduce participants to DeepHyper, a scalable automated machine learning package for developing deep neural networks. DeepHyper provides an infrastructure that targets experimental research in neural architecture search (NAS) and hyperparameter search (HPS) methods, scalability, and portability across diverse supercomputers through the use of the different workflow manager.
Speaker: Prasanna Balaprakash, Computer Scientist, Argonne National Laboratory
Bio: Prasanna Balaprakash is a computer scientist with a joint appointment in the Mathematics and Computer Science Division and the Leadership Computing Facility at Argonne National Laboratory. His research work spans the areas of artificial intelligence, machine learning, optimization, and high-performance computing. He is a recipient of the U.S. Department of Energy 2018 Early Career Award. Prior to Argonne, he worked as a Chief Technology Officer at Mentis Sprl, a machine learning startup in Brussels, Belgium. He received his PhD from CoDE-IRIDIA (AI Lab), UniversitÃ Libre de Bruxelles, Brussels, Belgium, where he was a recipient of European Commissions Marie Curie and Belgian F.R.S-FNRS Aspirant fellowships.
Presenter Website: http://pbalapra.github.io/
Department Link: https://deephyper.readthedocs.io/en/latest/

CSRC Colloquium - Sven Leffer
2023-03-03 15:30 - 16:30 | Virtual Zoom Seminar
Title: Nonlinear Optimization at the National Labs
Abstract: We review a range of challenging DOE applications in design and control that are formulated as nonlinear optimization problems, ranging from the modeling of gas and electricity networks, over the design of new materials, to the analysis of complex data. We show how research into new algorithms and solution techniques enables DOE scientists to solve these applications.
Speaker: Sven Leffer, Mathematics and Computer Science, Argonne National Laboratory
Bio: Sven Leyffer joined the Mathematics and Computer Science Division at Argonne in 2002, where he is now a senior computational mathematician. Sven is a SIAM Fellow, and a senior fellow of the University of Chicago/Argonne Computation Institute. Leyffer obtained his Ph.D. in 1994 from the University of Dundee, Scotland, and held postdoctoral research positions at Dundee, Argonne, and Northwestern University.
Presenter Website: https://wiki.mcs.anl.gov/leyffer/
Host: Jose Castillo (CSRC) and the Sustainable Horizons Institute CRLC Virtual Seminar Series

CSRC Colloquium - Youngsoo Choi
2023-02-03 15:30 - 16:30 | Virtual Zoom Seminar
Title: Physics-constrained data-driven methods for accurately accelerating simulations
Abstract: A data-driven model can be built to accurately accelerate computationally expensive physical simulations, which is essential in multi-query problems, such as inverse problem, uncertainty quantification, design optimization, and optimal control. In this talk, two types of data-driven model order reduction techniques will be discussed, i.e., the black-box approach that incorporates only data and the physics-constrained approach that incorporates the first principle as well as data. The advantages and disadvantages of each method will be discussed. Several recent developments of generalizable and robust data-driven physics-constrained reduced order models will be demonstrated for various physical simulations as well. For example, a hyper-reduced time-windowing reduced order model overcomes the difficulty of advection-dominated shock propagation phenomenon, achieving a speed-up of O(20~100) with a relative error much less than 1% for Lagrangian hydrodynamics problems, such as 3D Sedov blast problem, 3D triple point problem, 3D Taylor Green vortex problem, 2D Gresho vortex problem, and 2D Rayleigh Taylor instability problem. The nonlinear manifold reduced order model also overcomes the challenges posed by the problems with Kolmogorov’s width decaying slowly by representing the solution field with a compact neural network decoder, i.e., nonlinear manifold. The space time reduced order model accelerates a large-scale particle Boltzmann transport simulation by a factor of 2,700 with a relative error less than 1%. Furthermore, successful application of these reduced order models for mate-material lattice structure design optimization problems will be presented. Finally, the library for reduced order modeling tool, i.e., libROM (https://www.librom.net), and its webpage and several YouTube tutorial videos will be introduced.
Speaker: Youngsoo Choi, Research Scientist, Lawrence Livermore National Laboratory
Bio: Youngsoo is a research scientist in Center for Applied Scientific Computing at LLNL. His research focuses on developing efficient reduced order models for various physical simulations for time-sensitive decision-making multi-query problems, such as inverse problems, design optimization, and uncertainty quantification. His expertise includes various scientific computing disciplines. He has also developed the component-wise reduced order model optimization algorithm, which enables fast and accurate computational modeling tool for lattice-structure design. He is currently leading data-driven surrogate modeling development team for various physical simulations, with whom he developed an open source code, libROM. He has earned his undergraduate degree for Civil and Environmental Engineering from Cornell University and his PhD degree for Computational and Mathematical Engineering from Stanford University. He was a postdoc at Sandia National Laboratories and Stanford University prior to joining LLNL in 2017.
Presenter Website: https://people.llnl.gov/choi15
Department Link: https://computing.llnl.gov/casc

Host: Jose Castillo (CSRC) and the Sustainable Horizons Institute CRLC Virtual Seminar Series

CSRC Colloquium - Bashir Mohammed
2022-12-02 15:30 - 16:30 | Virtual Zoom Seminar
Title: Towards an Intelligent Self-Learning Network for Science
Abstract: Without human intervention, network automation promises configuration, management, testing, deployment, and network infrastructure operations. Although a self-driving network is still at its early stage, many time-consuming and complex network management tasks are being automated; thanks to the virtualization of network components, software-defined networking, advancements in artificial intelligence, and insights learned from data. In the first part of my talk, I will discuss my work at Berkeley Lab and how we have explored novel machine learning techniques to allow distributed high-speed network infrastructures to learn intelligently. I will then conclude by demonstrating how we applied some of the novel techniques in multidisciplinary collaborative research with the applied physics division at the Lab.

Speaker: Bashir Mohammed, Scientific Data Division, Berkeley Lab
Bio: Bashir Mohammed is a postdoctoral research scientist working on the Deep Learning and Artificial Intelligence High-Performance Networks (DAPHNE) project at Berkeley Lab. His current research focuses on developing AI and machine-learning algorithms to optimally control high-speed distributed network resources, minimize network downtime and avoid network traffic congestion for critical exascale scientific workflows. Bashir received his MS in Control Systems from the University of Sheffield and a Ph.D. in Computer Science from the University of Bradford UK, before moving to the United States in 2019 to start his postdoctoral work. He interned with Rolls-Royce in Sheffield, where he developed a control and optimization algorithm to model gas turbine engines. In 2019 he was among six postdoctoral fellows from US National Labs invited to Washington DC to speak to the Capitol Hill audience about their research. Outside the Lab, Bashir enjoys playing basketball while pursuing his love of acting on stage in local theatres.
Presenter Website: https://bashirmohd.github.io/
Department Link: https://crd.lbl.gov/divisions/scidata/sdm/staff/bashir-mohammed/
Host: Jose Castillo (CSRC) and the Sustainable Horizons Institute CRLC Virtual Seminar Series

*Cancelled* CSRC Colloquium - Hichem Hajaiej
2022-11-18 15:30 - 16:30 | GMCS 314
*Please note, this event has been cancelled*
Title: From Carthage to the World
Abstract: We will discuss major contributions to the field of rearrangement inequalities in the continuous setting and their applications in optics, physics, and other fields. We will also talk about symmetrization in the discrete case, which seems to have very promising applications in computer science. Many open questions are still unsolved in this direction.
Speaker: Hichem Hajaiej, Mathematics, CSU Los Angeles
Host: Ricardo Carretero
