Showing 2151 - 2160 of 5831 Items
Date: 2024-01-01
Creator: David Ma
Access: Open access
- Particle swarm optimization (PSO) is a metaheuristic optimization method that finds near- optima by spawning particles which explore within a given search space while exploiting the best candidate solutions of the swarm. PSO algorithms emulate the behavior of, say, a flock of birds or a school of fish, and encapsulate the randomness that is present in natural processes. In this paper, we discuss different initialization schemes and meta-optimizations for PSO, its performances on various multi-minima functions, and the unique intricacies and obstacles that the method faces when attempting to produce images for basins of attraction, which are the sets of initial points that are mapped to the same minima by the method. This project compares the relative strengths and weaknesses of the Particle Swarm with other optimization methods, namely gradient-descent, in the context of basin mapping and other metrics. It was found that with proper parameterization, PSO can amply explore the search space regardless of initialization. For all functions, the swarm was capable of finding, within some tolerance, the global minimum or minima in fewer than 60 iterations by having sufficiently well chosen parameters and parameterization schemes. The shortcomings of the Particle Swarm method, however, are that its parameters often require fine-tuning for different search spaces to most efficiently optimize and that the swarm cannot produce the analytical minimum. Overall, the PSO is a highly adaptive and computationally efficient method with few initial restraints that can be readily used as the first step of any optimization task.
Date: 2018-05-01
Creator: Angela M Dahl
Access: Open access
Date: 2013-09-01
Creator: Kanokwan Champasa, Scott A. Longwell, Aimee M. Eldridge, Elizabeth A. Stemmler, Danielle H., Dube
Access: Open access
- Virulence of the gastric pathogen Helicobacter pylori (Hp) is directly linked to the pathogen's ability to glycosylate proteins; for example, Hp flagellin proteins are heavily glycosylated with the unusual nine-carbon sugar pseudaminic acid, and this modification is absolutely essential for Hp to synthesize functional flagella and colonize the host's stomach. Although Hp's glycans are linked to pathogenesis, Hp's glycome remains poorly understood; only the two flagellin glycoproteins have been firmly characterized in Hp. Evidence from our laboratory suggests that Hp synthesizes a large number of as-yet unidentified glycoproteins. Here we set out to discover Hp's glycoproteins by coupling glycan metabolic labeling with mass spectrometry analysis. An assessment of the subcellular distribution of azide-labeled proteins by Western blot analysis indicated that glycoproteins are present throughout Hp and may therefore serve diverse functions. To identify these species, Hp's azide-labeled glycoproteins were tagged via Staudinger ligation, enriched by tandem affinity chromatography, and analyzed by multidimensional protein identification technology. Direct comparison of enriched azide-labeled glycoproteins with a mock-enriched control by both SDS-PAGE and mass spectrometry-based analyses confirmed the selective enrichment of azide-labeled glycoproteins. We identified 125 candidate glycoproteins with diverse biological functions, including those linked with pathogenesis. Mass spectrometry analyses of enriched azide-labeled glycoproteins before and after cleavage of O-linked glycans revealed the presence of Staudinger ligation-glycan adducts in samples only after beta-elimination, confirming the synthesis of O-linked glycoproteins in Hp. Finally, the secreted colonization factors urease alpha and urease beta were biochemically validated as glycosylated proteins via Western blot analysis as well as by mass spectrometry analysis of cleaved glycan products. These data set the stage for the development of glycosylation-based therapeutic strategies, such as new vaccines based on natively glycosylated Hp proteins, to eradicate Hp infection. Broadly, this report validates metabolic labeling as an effective and efficient approach for the identification of bacterial glycoproteins. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.
Date: 2018-05-01
Creator: Corinne Alini
Access: Open access
- Computer Vision involves the extraction of data from images that are analyzed in order to provide information crucial to many modern technologies. Object recognition has proven to be a difficult task and programming reliable object recognition remains elusive. Image processing is computationally intensive and this issue is amplified on mobile platforms with processor restrictions. The real-time constraints demanded by robotic soccer in RoboCup competition serve as an ideal format to test programming that seeks to overcome these challenges. This paper presents a method for ball recognition by analyzing the movement of the ball. Major findings include enhanced ball discrimination by replacing the analysis of static images with absolute change in brightness in conjunction with the classification of apparent motion change.
Date: 2014-05-01
Creator: Graham Harper Edwards
Access: Open access
- Morainal and lacustrine sediments in Linnédalen, Spitsbergen, Svalbard, record the fluctuations of a glacier in a currently unglaciated mountain cirque during the Little Ice Age (LIA). This study attempts to reconstruct Late Holocene glacial activity within this cirque from geochemical, physical, and visual stratigraphic variation of the Linnévatnet lacustrine sediment record. A 57 cm lacustrine sediment core (D10.5) from Linnévatnet was analyzed at a high-resolution for variations in X-Ray Fluorescence (XRF)-measured elemental composition, spectral reflectance, and magnetic susceptibility. The visual stratigraphy was observed at a microscopic scale. An age-depth model for D10.5 is developed by extrapolating sedimentation rates from dated horizons, measured by 239+240Pu radionuclide fallout dating and chemostratigraphic enrichment of atmospheric anthropogenic pollutants. Visual stratigraphy of the sediment record indicates two periods of cirque glacier sediment delivery to Linnévatnet during the LIA (1329-1363 CE, 1816 CE-Present) and a third period of sediment delivery during the Medieval Climate Anomaly (MCA; 984-1082 CE). During non-glacial periods, stratigraphic variation in XRF-measured Ti and K appear to be associated with fluctuations in North Atlantic Oscillation (NAO)-regulated precipitation. Within the LIA glacial intervals, decadal-scale variations in sediment Ti and K geochemistry may result from advance and retreat of the cirque glacier ice-margin or fluctuations in precipitation. Stratigraphic variation in Fe content indicates complex erosional and hydrological processes associated with MCA precipitation and glacial meltwater. Stratigraphic and geochemical variations in the lacustrine record of Linnévatnet indicate that both cirque glacier activity and sediment transport in Linnédalen are more sensitive to climatological change than previously thought.
Date: 2019-05-01
Creator: James Little
Access: Open access
- Isolation-Based Scene Generation (IBSG) is a process for creating synthetic datasets made to train machine learning detectors and classifiers. In this project, we formalize the IBSG process and describe the scenarios—object detection and object classification given audio or image input—in which it can be useful. We then look at the Stanford Street View House Number (SVHN) dataset and build several different IBSG training datasets based on existing SVHN data. We try to improve the compositing algorithm used to build the IBSG dataset so that models trained with synthetic data perform as well as models trained with the original SVHN training dataset. We find that the SVHN datasets that perform best are composited from isolations extracted from existing training data, leading us to suggest that IBSG be used in situations where a researcher wants to train a model with only a small amount of real, unlabeled training data.
Date: 2008-11-17
Creator: Leon G. Billings
Access: Open access
Biographial Note
Leon Billings was born in Helena, Montana, on November 19, 1937. His parents, Harry and Gretchen Billings, were progressive journalists. He was graduated from high school in Helena, Montana, in 1955 and then attended Reed College for one year in Portland, Oregon. He completed his undergraduate studies and took graduate courses toward an M.A. at the University of Montana. Billings worked as a reporter and organizer for farm groups in Montana and California. He met his first wife, Pat, in California; they married in Montana and moved to Washington, D.C., on January 4, 1963. While in Washington, Billings worked for the American Public Power Association for three years as a lobbyist. In March 1966, he accepted a job on the Subcommittee on Air and Water Pollution on the Public Works Committee. He worked for Sen. Edmund Muskie helping to coordinate work on environmental policy. From 1966 to 1978, he served as Muskie’s chief of staff. He served on the Democratic Platform Committee staff in 1968 and in 1974 was co-chairman of a Democratic National Committee task force on Energy and the Environment. He later served as president of the Edmund S. Muskie Foundation, a tax-exempt foundation endowed with an appropriation from Congress to perpetuate the environmental legacy of Senator Muskie. Leon Billings passed away on November 15, 2016.
Summary
Interview includes discussion of: Edmund S. Muskie's political career and vice-presidential campaign (1968); Mitchell's 1974 Maine gubernatorial campaign (1974) and his U.S. Senate appointment (1980); environmental legislation; personal comparisons between Muskie and Mitchell and comparisons of their respective administrative offices; and Mitchell's decision to retire from the U.S. Senate.
Date: 2009-06-16
Creator: Charlene Sturbitts
Access: Open access
Biographial Note
Charlene Sturbitts was born in Evanston, Illinois, on June 16, 1950, to Mary Jane and William Sturbitts. She grew up in Washington, D.C., where her father was employed on the overt side of the CIA. She attended private schools and Sweet Briar College, where she volunteered for the Muskie presidential primary campaign. After graduating from college, she spent a summer as an intern on the Subcommittee on Air and Water Pollution and was then hired in the fall by Leon Billings as a researcher for the subcommittee. She attended law school at night at Catholic University while continuing her work preparing drafts for what would become the 1977 Clean Air Amendment, graduating in late 1978. When Senator Muskie left the Senate to become secretary of state, Charlene was asked by George Mitchell to join his staff working on environmental issues. She became his legislative director before leaving after five years to work as a lawyer. At the time of this interview, she was an attorney and advisor in the Office of Legislation and Regulatory Law in the Office of the General Counsel of the U.S. Department of Energy.
Summary
Interview includes discussion of: how Sturbitts became interested in politics; volunteering on the Muskie campaign; first became aware of Mitchell; how she was hired by Mitchell; the difference between working on a committee staff and a personal staff; the first environmental legislation Sturbitts worked on for Mitchell, putting environmental protections into legislation that changed coal power plants over to natural gas; how Mitchell became interested in environmental matters and acid rain, and how that became an issue in his 1982 campaign; positioning Mitchell as the ranking member of a subcommittee; becoming Mitchell’s legislative director and what the job entailed; staff meetings; the chief of staff’s role and the power structure in Mitchell’s office; Mitchell’s leadership style within the office; Mitchell’s position on the Tennessee-Tombigbee project; field hearings; comparing Mitchell and Muskie’s offices; issues that were priorities for Mitchell; Senators Moynihan, Simpson, Stafford, and Bentsen; Dole’s role under the Reagan administration; Mitchell’s relationship with the Reagan administration; Sturbitts’s decision to leave the Senate office; her reaction to Mitchell’s decision to retire; changes Sturbitts has observed on the Hill and in the attitudes of those who work there; Gayle Cory’s role; the attitude toward women on the Hill and how it has evolved over time; Sturbitts’s current job at the Department of Energy; and Mitchell’s contribution to the Senate.
Date: 2009-07-17
Creator: William 'Bill' W Bradley
Access: Open access
Biographial Note
William Warren “Bill” Bradley was born July 28, 1943, in Crystal City, a suburb of St. Louis, Missouri. His parents were Warren and Susan Bradley, a banker and a teacher respectively. He excelled academically and athletically, as a basketball player, through high school. He entered Princeton in 1961, and in 1964 he was a member of the gold-medal Olympic basketball team before going on to be named the 1965 NCAA Player of the Year during his senior year. He won a Rhodes Scholarship to study at Oxford for two years. Upon returning to the U.S., he played professional basketball for the New York Knicks from the 1967-1968 season until his retirement in 1977. Subsequently, he determined to run for the U.S. Senate from New Jersey; he was elected in 1978 and re-elected in 1984 and 1990. He left the Senate in 1997, and in 1999 he announced his candidacy for the 2000 presidential election. Failing to win the Democratic nomination, he supported Al Gore. He has published six non-fiction books, is a corporate director of Starbucks, and is a partner at the investment bank Allen & Company in New York City.
Summary
Interview includes discussions of: the bipartisan group in the U.S. Senate class of 1978; Bradley’s appointments to the Finance Committee and Energy and Natural Resources Committee; getting to know Mitchell on the Finance Committee; debating the 1986 tax bill; Mitchell’s election to majority leader; Finance issues when Reagan was coming into office and the 1980s; Mitchell’s major contributions as a legislator; Mitchell’s involvement with health care; the frustration surrounding the Iran-Contra investigation; Mitchell as a great majority leader; Bradley’s public statement that “politics was broken;” Bradley’s run for president and Mitchell’s help; contacts with Mitchell and his appointment by Obama; and the trip to the Soviet Union with Mitchell.
Date: 2008-08-07
Creator: Janet 'Jan' P Barrett
Access: Open access
Biographial Note
Jan (Plourde) (Welch) Barrett was born and raised in Lewiston, Maine. Her father was in the military and, although she and her mother traveled with him, they always returned to Lewiston-Auburn and stayed with her grandparents, the Duponts, owners of Sonny Boy Bread. She attended St. Louis School until the eighth grade and was graduated from Lewiston High School in 1965. Barrett attended two years at the Chandler's School for Women in Boston. After college, she stayed in Boston for work, meeting Don Nicoll after graduation; a few months later he offered her a job on Senator Muskie’s staff as the secretary to the press secretary. She worked in the Waterville state Senate office during Muskie’s tenure until he left the Senate in 1980 and continued with Senator Mitchell until his retirement in 1995.
Summary
Interview includes discussion of: Lewiston/Auburn community; Don Nicoll; Muskie vice presidential campaign of 1968; Mitchell senate years; Mitchell’s personality; diplomacy of both Mitchell and Muskie; the pride she took in her work and the honor and prestige she felt working for Mitchell; and Jan’s role in the original organization of the Muskie Archives.