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Radiofrequency ice dielectric measurements at Summit Station, Greenland
- Juan Antonio Aguilar, Patrick Allison, Dave Besson, Abby Bishop, Olga Botner, Sjoerd Bouma, Stijn Buitink, Maddalena Cataldo, Brian A. Clark, Kenny Couberly, Zach Curtis-Ginsberg, Paramita Dasgupta, Simon de Kockere, Krijn D. de Vries, Cosmin Deaconu, Michael A. DuVernois, Anna Eimer, Christian Glaser, Allan Hallgren, Steffen Hallmann, Jordan Christian Hanson, Bryan Hendricks, Jakob Henrichs, Nils Heyer, Christian Hornhuber, Kaeli Hughes, Timo Karg, Albrecht Karle, John L. Kelley, Michael Korntheuer, Marek Kowalski, Ilya Kravchenko, Ryan Krebs, Robert Lahmann, Uzair Latif, Joseph Mammo, Matthew J. Marsee, Zachary S. Meyers, Kelli Michaels, Katharine Mulrey, Marco Muzio, Anna Nelles, Alexander Novikov, Alisa Nozdrina, Eric Oberla, Bob Oeyen, Ilse Plaisier, Noppadol Punsuebsay, Lilly Pyras, Dirk Ryckbosch, Olaf Scholten, David Seckel, Mohammad Ful Hossain Seikh, Daniel Smith, Jethro Stoffels, Daniel Southall, Karen Terveer, Simona Toscano, Delia Tosi, Dieder J. Van Den Broeck, Nick van Eijndhoven, Abigail G. Vieregg, Janna Z. Vischer, Christoph Welling, Dawn R. Williams, Stephanie Wissel, Robert Young, Adrian Zink
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- Journal:
- Journal of Glaciology , First View
- Published online by Cambridge University Press:
- 09 October 2023, pp. 1-12
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We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.
Combining satisfiability techniques from AI and OR
- HEIDI E. DIXON, MATTHEW L. GINSBERG
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- Journal:
- The Knowledge Engineering Review / Volume 15 / Issue 1 / March 2000
- Published online by Cambridge University Press:
- 06 March 2012, pp. 31-45
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The recent effort to integrate techniques from the fields of artificial intelligence and operations research has been motivated in part by the fact that scientists in each group are often unacquainted with recent (and not so recent) progress in the other field. Our goal in this paper is to introduce the artificial intelligence community to pseudo-Boolean representation and cutting plane proofs, and to introduce the operations research community to restricted learning methods such as relevance-bounded learning. Complete methods for solving satisfiability problems are necessarily bounded from below by the length of the shortest proof of unsatisfiability; the fact that cutting plane proofs of unsatisfiability can be exponentially shorter than the shortest resolution proof can thus in theory lead to substantial improvements in the performance of complete satisfiability engines. Relevance-bounded learning is a method for bounding the size of a learned constraint set. It is currently the best artificial intelligence strategy for deciding which learned constraints to retain and which to discard. We believe these two elements or some analogous form of them are necessary ingredients to improving the performance of satisfiability algorithms generally. We also present a new cutting plane proof of the pigeonhole principle that is of size n2, and show how to implement some intelligent backtracking techniques using pseudo-Boolean representation.
Rogues' Gallery of Contributing Authors
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- By Ramon Abola, Rishimani Adsumelli, Syed Azim, Tazeen Beg, Helene Benveniste, Louis Chun, Ramtin Cohanim, Dominick Coleman, Joseph Conrad, Tommy Corrado, Jason Daras, Michelle DiGuglielmo, Vedan Djesevic, Andrew Drollinger, Kathleen Dubrow, Brian Durkin, Ralph Epstein, Christopher J. Gallagher, Xiaojun Guo, Sofie Hussain, Ron Jasiewicz, Anna Kogan, Ursula Landman, Rany Makaryus, Daryn Moller, Tate Montgomery, Matthew Neal, Khoa Nguyen, Marco Palmieri, Shaji Poovathor, Eric Posner, Deborah Richman, Andrew Rozbruch, Misako Sakamaki, Joy Schabel, Bharathi Scott, Peggy Seidman, Shiena Sharma, Vishal Sharma, Ellen Steinberg, Neera Tewari, Jane Yi, Jonida Zeqo, Peter Chung, John Denny, Steven H. Ginsberg, Jeremy Grayson, Jonathan Kraidin, Stephen Lemke, Tejal Patel, Salvatore Zisa, Charles Cowles, Marc Rozner, Shawn Banks, Deborah Brauer, Lebron Cooper, V. Samepathi David, Steve Gayer, Steven Gil, Eric A. Harris, Murlikrishna Kannan, Michael C. Lewis, David A. Lindley, Carlos M. Mijares, Sana Nini, Shafeena Nurani, Sujatha Pentakota, Edgar Pierre, Amy Klash Pulido, Michael Rossi, Miguel Santos, Nancy Setzer-Saade, Adam Sewell, Omair H. Toor, Ashish Udeshi, Patricia Wawroski, Lauren C. Berkow, Dan Berkowitz, Ramola Bhambhani, Kerry K. Blaha, Veronica Busso, Adam J. Carinci, Paul J. Christo, R. Blaine Easley, Ralph J. Fuchs, Samuel M. Galvagno, Nishant Gandhi, Andrew Goins, Robert S. Greenberg, Sayeh Hamzehzadeh, Theresa L. Hartsell, Eugenie Heitmiller, Jeremy M. Huff, Brijen L. Joshi, Sapna Kudchadkar, Jennifer K. Lee, Ira Lehrer, Peter Lin, Justin Lockman, Christine L. Mai, Christina Miller, Nanhi Mitter, Gillian Newman, Daniel Nyhan, Lale Odekon, Rabi Panigrahi, Melissa Pant, Alexander Papangelou, Mark Rossberg, Adam Schiavi, Steven J. Schwartz, Deborah A. Schwengel, Brandon M. Togioka, Tina Tran, Emmett Whitaker, Bradford D. Winters, Christopher Wu, Elena J. Holak, Paul S. Pagel
- Edited by Christopher J. Gallagher, State University of New York, Stony Brook, Michael C. Lewis, University of Miami School of Medicine, Deborah A. Schwengel
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- Book:
- Core Clinical Competencies in Anesthesiology
- Published online:
- 06 July 2010
- Print publication:
- 12 April 2010, pp xi-xii
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