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44 NERSC ANNUAL REPORT 2015 ‘Data Deluge’ Pushes MSI Analysis to New Heights MANTISSA: Massive Acceleration of New Techniques in Science with Scalable Algorithms ASCR—Applied Math, BER—Biological Systems Science Principal Investigators: Prabhat, Lawrence Berkeley National Laboratory; Ben Bowen, University of California, Berkeley OBJECTIVE Researchers are combining mathematical theory and scalable algorithms with computational resources at NERSC to address growing data-management challenges in climate research, high-energy physics and the life sciences. FINDINGS/ACCOMPLISHMENTS To develop better methods for analyzing large datasets, in 2014 Berkeley Lab launched a project dubbed MANTISSA (Massive Acceleration of New Technologies in Science with Scalable Algorithms). MANTISSA’s first order of business was to improve data analysis in mass spectrometry imaging (MSI). Datasets from MSI provide unprecedented characterization of the amount and spatial distribution of molecules in a sample, leading to detailed investigations of metabolic and microbial processes at subcellular to centimeter resolutions. But the raw datasets range from gigabytes to terabytes in size, which can be a challenge for even large computing systems to wade through efficiently. Ion-intensity visualization of the 20 most important ions in a mouse brain segment selected by the CX/CUR algorithm. Of the 20 ions, little redundancy is present, pointing to the effectiveness of the CX approach for information prioritization. Image: Ben Bowen, Lawrence Berkeley National Laboratory Studies applying MANTISSA’s algorithms to MSI datasets have demonstrated how a mathematical theory such as randomized linear algebra (RLA)—commonly used in engineering, computational science and machine learning for image processing and data mining—can be combined with one of the most sophisticated imaging modalities in life sciences to enhance scientific progress. RESEARCH DETAILS Researchers from UC Berkeley and Berkeley Lab ran computations involving two RLA algorithms—CX and CUR—on NERSC’s Edison system using two MSI datasets: mammalian brain and lung sections. They found that using these algorithms streamlined the data analysis process and yielded results that were easier to interpret because they prioritized specific elements in the data. Publication: J. Yang, O. Rubel, Prabhat, M. Mahoney, B.P. Bowen, “Identifying important ions and positions in mass spectrometry imaging data using CUR matrix decompositions,” Analytical Chemistry, 87 (9), 4658-4666, March 31, 2015, doi: 10.1021/ac5040264 Full Story: http://bit.ly/NERSCarMSIDatasets
Science Highlights 45 Could Material Defects Actually Improve Solar Cells? Doping bottleneck, van der Waals Interaction and Novel Ordered Alloy BES—Materials Science OBJECTIVE Scientists at the National Renewable Energy Laboratory (NREL) are using supercomputers to study what may seem paradoxical: that certain defects in silicon solar cells may actually improve their performance. Principal Investigator: Suhuai Wei, National Renewable Energy Laboratory FINDINGS/ACCOMPLISHMENTS Deep-level defects frequently hamper the efficiency of solar cells, but this theoretical research suggests that defects with properly engineered energy levels can improve carrier collection out of the cell or improve surface passivation of the absorber layer. For solar cells and photoanodes, engineered defects could possibly allow thicker, more robust carrier-selective tunneling transport layers or corrosion protection layers that might be easier to fabricate. RESEARCH DETAILS Researchers at NREL ran simulations to add impurities to layers adjacent to the silicon wafer in a solar cell. Namely, they introduced defects within a thin tunneling silicon dioxide layer that forms part of the “passivated contact” for carrier collection and within the aluminum oxide surface passivation layer next to the silicon (Si) cell wafer. In both cases, specific defects were identified to be beneficial. NERSC’s Hopper system was used to calculate various defect levels; the researchers ran a total of 100 calculations on Hopper, with each calculation taking approximately eight hours on 192 cores. Deep-level defects frequently hamper the efficiency of solar cells, but NREL research suggests that defects with properly engineered energy levels can improve carrier collection out of the cell. Image: Roy Kaltschmidt, Lawrence Berkeley National Laboratory Publication: Y. Liu, P. Stradins, H. Deng, J. Luo, S. Wei, “Suppress carrier recombination by introducing defects: The case of Si solar cell,” Applied Physics Letters 108, 022101, January 11, 2016. Full Story: http://bit.ly/NERSCarMaterialDefects
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Page 5 and 6: Table of Contents 3 User Support an
Page 7 and 8: Director's Note 5 In parallel with
Page 9 and 10: NERSC User/Usage Demographics 7 201
Page 15 and 16: Innovations 13 Paving the Way to Ex
Page 17 and 18: Innovations 15 full benefit of the
Page 19 and 20: Innovations 17 Data-Intensive Scien
Page 21 and 22: Innovations 19 installing it on Cra
Page 23 and 24: Innovations 21 The Palomar 48-inch
Page 25 and 26: Innovations 23 distributed data cen
Page 27 and 28: Innovations 25 Operational Excellen
Page 29 and 30: Innovations 27 Environmental Data C
Page 31 and 32: Innovations 29 Despite being target
Page 33 and 34: Science Highlights 31 Simulations L
Page 35 and 36: Science Highlights 33 33 Stabilizin
Page 37 and 38: Science Highlights 35 BISICLES Ice
Page 39 and 40: Science Highlights 37 Supernova Hun
Page 41 and 42: Science Highlights 39 Celeste: A Ne
Page 43 and 44: Science Highlights 41 What Causes E
Page 45: Science Highlights 43 What Ignites
Page 49 and 50: User Support and Outreach 47 NERSC
Page 51 and 52: User Support and Outreach 49 Other
Page 53 and 54: User Support and Outreach 51 Prelim
Page 55 and 56: User Support and Outreach 53 A view
Page 57 and 58: User Support and Outreach 55 Additi
Page 59 and 60: User Support and Outreach 57 The co
Page 61 and 62: Center News 59 NERSC’s New Home:
Page 63 and 64: Center News 61 performance of 1.28
Page 65 and 66: Center News 63 long-term climate da
Page 67 and 68: Center News 65 NERSC’s connection
Page 69 and 70: Center News 67 NERSC 2016 AWARD FOR
Page 71 and 72: Center News 69 In addition to the n
Page 73 and 74: NERSC Director’s Reserve 71 PROJE
Page 75 and 76: Publications 73 Publications Stayin
Page 77 and 78: Appendices 75 Appendix B Office of
Page 79 and 80: Appendices 77 InN Indium Nitride Me
Page 81: DISCLAIMER This document was prepar

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