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InTheLoop | 04.21.2014

April 21, 2014

Clocking the Early Universe's Expansion Rate

Astronomers have made the most accurate calculation yet of the expansion rate of the young Universe with help from supercomputers at the U.S. Department of Energy’s National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory (Berkeley Lab). Their findings could help scientists discover the nature of dark energy, the mysterious, repulsive force that pervades our universe causing it to expand at an accelerating rate. 

By analyzing the light of distant quasars gathered by the Baryon Oscillation Spectroscopic Survey (BOSS), two teams of scientists found the 4 billion year-old Universe was expanding by one percent every 44 million years. Measuring this rate over the Universe’s entire history is key to determining the nature of the dark energy. Understanding dark energy, in turn, informs our understanding of the fundamental nature of our Universe. »Read more.

NERSC, CRD Security Experts Featured in New York Times Heartbleed Coverage

The New York Times turned to security researchers at Berkeley Lab’s Computational Research Division and NERSC in their April 16 coverage of the Heartbleed SSL vulnerability. Vern Paxson, a CRD researcher who authored the Bro Network Security Monitor in the 1990s, and Jim Mellander of NERSC, among others, found that it is still possible to look for past Heartbleed exploits by measuring the size of any messages sent to the vulnerable part of the OpenSSL code, called the Heartbeat, and the size of the information request that hit a server. The team worked with other Bro users to implement signature detection for Heartbleed and then ran historical data through the signature looking for any past attempts to see if they were successful. »Read more.

Michael Wehner Discusses Climate Change on Pacifica Radio

CRD's Michael Wehner was interviewed on Pacifica Radio network show about climate modelling and climate change on April 7. His interview followed the release of the second part of the most recent United Nations Intergovernmental Panel on Climate Change (IPCC) report. Wehner's segment begins at around the 7 minute mark. »Listen to the interview.

Tomorrow: Recycle Unwanted Electronics on Earth Day

As part of its Earth Day events, Sustainable Berkeley Lab and EHS have partnered with the US Postal service to collect unwanted electronics for recycling. Drop off items at the cafeteria from 11am to 1:30pm on Earth Day, April 22. A collection box will be available in the OSF lobby area that same day.

  • This program is for personal items only, not LBNL or DOE property.
  • Some examples of items accepted include cell phones, tablets, digital cameras, laptops, PCs, servers, and storage devices (up to 20 pounds).
  • Any personal information left on an item will be wiped clean following NIST 800-88 guidelines (the protocol used by the Department of Defense).
  • Before dropping off your tablet, cell phone or smartphone, consider visiting BlueEarth.usps.gov to determine if it qualifies for cash back. If it does, you are encouraged to ship your package directly with the USPS. »Get more information.
  • If you cannot make it to the cafeteria, volunteers will be available to pick up items. »Request a pick up.

Berkeley Lab Scientists Host 12 Albany Students for Annual Job Shadow Day

For the sixth consecutive year, researchers across Berkeley Lab hosted 12 juniors from Albany High School in conjunction with the school’s annual Job Shadow Day. In advance of the event, students select areas of career interest and parent volunteers match them with mentors around the Bay Area. Ten of the students spent the morning of Thursday, April 10 at the lab, ending their visit with lunch with their mentors. Two other students gave up a day of their spring break to visit mentors on April 15 and 17. Six CRD staffers hosted seven Albany HS students. Jon Bashor, Computing Sciences communications manager, organized the mentor-student matchups. »Read more and see photos.

Alice Koniges Profiled by Scientific Computing

Alice Koniges of NERSC was recently profiled by Scientific Computing where we learn that Koniges was first woman to earn a PhD in Applied and Computational Mathematics at Princeton University. She joined NERSC in 1984, when the center was still located at LLNL. »Read more.

Remembering NERSC's Roots

As part of NERSC's 40th anniversary celebration, Kirby Fong recalls the center's early days. When he arrived in June of 1976, the National Magnetic Fusion Energy Computer Center (NMFECC), as NERSC was then known, was running on a borrowed CDC 6600 computer and a CDC 7600 of its own. He recalls the ups and downs of the early days, including an earthquake that set a newly constructed machine room on its ear and taught some valuable lessons. »Read more

DOE Releases 2014 Strategic Plan

The Department of Energy last week released its 2014 Strategic Plan, a comprehensive blueprint to guide the agency's core mission of ensuring America's security and prosperity by addressing its energy, environmental, and nuclear challenges through transformative science and technology solutions.The DOE Strategic Plan is organized into 12 strategic objectives aimed at three objectives: science and energy, nuclear security and management and performance. These objectives represent the broad cross-cutting and collaborative efforts taking place across the department's headquarters, site offices and national laboratories. »Download the plan.

This Week's CS Seminars

Towards the Hybrid Simulation of Floating Vertical-Axis Wind Turbines

Wednesday, April 23, 3:30pm – 4:30pm, 939 Evans Hall, UC Berkeley Campus
Sam Kanner, University of California, Berkeley

Vertical-axis wind turbines (VAWTs) are becoming popular in the offshore wind energy field due to their superiority over horizontal-axis wind turbines (HAWTs) on a floating platform. Though they are more stable and easier to service than HAWTs, a single VAWT must have a more complex mooring system. A novel platform has been designed and will be tested at a model-scale using hybrid simulation. This type of simulation combines the advantages of both the experimental and computational domains, which is necessary for such a model that is subject to varying winds and waves. In order to simulate the aerodynamics of the turbines, a high-order discontinuous Galerkin ILES method is first used to estimate the forces on a single airfoil in 2D and 3D over large angles of attack at low chord Reynolds numbers. This methodology is also applied to rotating wind turbines undergoing prescribed motion. The forces on the blades are compared to experimental data as well as analytical turbine models. Finally, some results from a moving mesh method using an element flipping technique are shown. The talk is based on joint work with Per-Olof Persson and Luming Wang (UC Berkeley).

Pole expansion for solving a type of parametrized linear systems

Thursday, April 24, 2:00pm - 3:00pm, 50B-2222
Anil Damle, Institute for Computational and Mathematical Engineering (ICME), Stanford University

Given a parmetrized linear system of the form (A-zI)x = b we would like to efficiently compute solutions for a large number of distinct z. When z has non-positive real part, A is Hermitian, and either A is positive definite or there are restrictions on b, solutions to this set of linear systems for all parameters can be accurately approximated by linear combinations of solutions to linear systems for a small set of fixed parameters. Combined with either direct solvers or preconditioned iterative solvers for each linear system with a fixed parameter, the method is particularly suitable for situations when solutions for a large number of distinct parameters or a large number of right hand sides are required. The method is also simple to parallelize. The applicability of the method is demonstrated via the calculation of the response functions in electronic structure theory. We demonstrate the numerical performance of the method using a benzene molecule and a DNA molecule.