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395 results on '"Knight, Joseph"'

1. On the EKL-Degree of a Weyl Cover

Author

Knight, Joseph, Swaminathan, Ashvin, and Tseng, Dennis

Subjects
Mathematics - Algebraic Geometry, Mathematics - Number Theory, Mathematics - Representation Theory, 14M15, 55M25, 14F42, 14G27
Abstract

More than four decades ago, Eisenbud, Khim\v{s}ia\v{s}vili, and Levine introduced an analogue in the algebro-geometric setting of the notion of local degree from differential topology. Their notion of degree, which we call the EKL-degree, can be thought of as a refinement of the usual notion of local degree in algebraic geometry that works over non-algebraically closed base fields, taking values in the Grothendieck-Witt ring. In this note, we compute the EKL-degree at the origin of certain finite covers $f\colon \mathbb{A}^n\to \mathbb{A}^n$ induced by quotients under actions of Weyl groups. We use knowledge of the cohomology ring of partial flag varieties as a key input in our proofs, and our computations give interesting explicit examples in the field of $\mathbb{A}^1$-enumerative geometry., Comment: 15 pages

Published
2019

2. Spatial Sciences and Research

Author

Fan, Yingling, Padilla, Irene Bueno, Haynes II, David, Kircher, Amy, Knight, Joseph, Krzyzanowski, Brittany, Pardey, Phil, Pelican, Katey, Singer, Randal, Shekhar, Shashi, Shook, Eric, Thorleifson, Harvey, Van Riper, David, Song, Ying, Manson, Steven M., editor, Kne, Len, editor, Krzyzanowski, Brittany, editor, and Lindelof, Jane, editor

Published
2022
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6. Correction to: Spatial Sciences and Research

Author

Fan, Yingling, primary, Padilla, Irene Bueno, additional, Haynes II, David, additional, Kircher, Amy, additional, Knight, Joseph, additional, Krzyzanowski, Brittany, additional, Pardey, Phil, additional, Pelican, Katey, additional, Singer, Randall, additional, Shekhar, Shashi, additional, Shook, Eric, additional, Thorleifson, Harvey, additional, Van Riper, David, additional, and Song, Ying, additional

Published
2022
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18. Using Voting-Based Ensemble Classifiers to Map Invasive Phragmites australis.

Author

Anderson, Connor J., Heins, Daniel, Pelletier, Keith C., and Knight, Joseph F.

Subjects
PHRAGMITES, PHRAGMITES australis, MACHINE learning, ARTIFICIAL neural networks, RANDOM forest algorithms, INVASIVE plants
Abstract

Machine learning is frequently combined with imagery acquired from uncrewed aircraft systems (UASs) to detect invasive plants. Having prior knowledge of which machine learning algorithm will produce the most accurate results is difficult. This study examines the efficacy of a voting-based ensemble classifier to identify invasive Phragmites australis from three-band (red, green, blue; RGB) and five-band (red, green, blue, red edge, near-infrared; multispectral; MS) UAS imagery acquired over multiple Minnesota wetlands. A Random Forest, histogram-based gradient-boosting classification tree, and two artificial neural networks were used within the voting-based ensemble classifier. Classifications from the RGB and multispectral imagery were compared across validation sites both with and without post-processing from an object-based image analysis (OBIA) workflow (post-machine learning OBIA rule set; post-ML OBIA rule set). Results from this study suggest that a voting-based ensemble classifier can accurately identify invasive Phragmites australis from RGB and multispectral imagery. Accuracies greater than 80% were attained by the voting-based ensemble classifier for both the RGB and multispectral imagery. The highest accuracy, 91%, was achieved when using the multispectral imagery, a canopy height model, and a post-ML OBIA rule set. The study emphasizes the need for further research regarding the accurate identification of Phragmites australis at low stem densities. [ABSTRACT FROM AUTHOR]

Published
2023
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22. Injectable Biomaterials in Surgery

Author

Shafi, Bilal, Mery, Carlos, Binyamin, Gary, Knight, Joseph, Gertner, Michael E., Norton, Jeffrey A., editor, Barie, Philip S., editor, Bollinger, R. Randal, editor, Chang, Alfred E., editor, Lowry, Stephen F., editor, Mulvihill, Sean J., editor, Pass, Harvey I., editor, and Thompson, Robert W., editor

Published
2008
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25. Improving Machine Learning Classifications of Phragmites australis Using Object-Based Image Analysis.

Author

Anderson, Connor J., Heins, Daniel, Pelletier, Keith C., and Knight, Joseph F.

Subjects
PHRAGMITES, PHRAGMITES australis, MACHINE learning, IMAGE analysis, SUPPORT vector machines, INTRODUCED plants
Abstract

Uncrewed aircraft systems (UASs) are a popular tool when surveilling for invasive alien plants due to their high spatial and temporal resolution. This study investigated the efficacy of a UAS equipped with a three-band (i.e., red, green, blue; RGB) sensor to identify invasive Phragmites australis in multiple Minnesota wetlands using object-based image analysis (OBIA) and machine learning (ML) algorithms: artificial neural network (ANN), random forest (RF), and support vector machine (SVM). The addition of a post-ML classification OBIA workflow was tested to determine if ML classifications can be improved using OBIA techniques. Results from each ML algorithm were compared across study sites both with and without the post-ML OBIA workflow. ANN was identified as the best classifier when not incorporating a post-ML OBIA workflow with a classification accuracy of 88%. Each of the three ML algorithms achieved a classification accuracy of 91% when incorporating the post-ML OBIA workflow. Results from this study suggest that a post-ML OBIA workflow can increase the ability of ML algorithms to accurately identify invasive Phragmites australis and should be used when possible. Additionally, the decision of which ML algorithm to use for Phragmites mapping becomes less critical with the addition of a post-ML OBIA workflow. [ABSTRACT FROM AUTHOR]

Published
2023
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30. Evaluation of a Text Compression Algorithm Against Computer-Aided Instruction (CAI) Material.

Author

Air Force Systems Command, L.G. Hanscom Field, MA. Electronic Systems Div. and Knight, Joseph M.

Abstract

This report describes the initial evaluation of a text compression algorithm against computer assisted instruction (CAI) material. A review of some concepts related to statistical text compression is followed by a detailed description of a practical text compression algorithm. A simulation of the algorithm was programed and used to obtain compression ratios for a small sample of both traditional frame-structured CAI material and a new type of information-structured CAI material. The resulting compression ratios are to 1.5: 1 for both types of material. The simulation program was modified to apply the algorithm to the lesson files of a particular frame-structured CAI subsystem used in the Air Force Phase II Base Level System. The compression in this case was found to be 1.3: 1 because some uncompressible, frame-formating bytes were present in the lesson file. The modified simulation program was also used to take letter occurrence statistics on the text being compressed. From these, a theoretical compression was calculated using a probalistic model of the compression algorithm. Theoretical compression was within two percent of measured compression, thus verifying the model's applicability. (Author)

Published
1972

31. Significant Attenuation of Lightly Damped Resonances Using Particle Dampers

Author

Smith, Andrew, LaVerde, Bruce, Hunt, Ron, and Knight, Joseph Brent

Subjects
Acoustics
Abstract

When equipment designs must perform in a broad band vibration environment it can be difficult to avoid resonances that affect life and performance. This is especially true when an organization seeks to employ an asset from a heritage design in a new, more demanding vibration environment. Particle dampers may be used to provide significant attenuation of lightly damped resonances to assist with such a deployment of assets by including only a very minor set of modifications. This solution may be easier to implement than more traditional attenuation schemes. Furthermore, the cost in additional weight to the equipment can be very small. Complexity may also be kept to a minimum, because the particle dampers do not require tuning. Attenuating the vibratory response with particle dampers may therefore be simpler (in a set it and forget it kind of way) than tuned mass dampers. The paper will illustrate the use of an "equivalent resonance test jig" that can assist designers in verifying the potential resonance attenuation that may be available to them during the early trade stages of the design. An approach is suggested for transforming observed attenuation in the jig to estimated performance in the actual service design. KEY WORDS: Particle Damper, Performance in Vibration Environment, Damping, Resonance, Attenuation, Mitigation of Vibration Response, Response Estimate, Response Verification.

Published
2015

40. Multi-Source EO for Dynamic Wetland Mapping and Monitoring in the Great Lakes Basin

Author

Battaglia, Michael J., primary, Banks, Sarah, additional, Behnamian, Amir, additional, Bourgeau-Chavez, Laura, additional, Brisco, Brian, additional, Corcoran, Jennifer, additional, Chen, Zhaohua, additional, Huberty, Brian, additional, Klassen, James, additional, Knight, Joseph, additional, Morin, Paul, additional, Murnaghan, Kevin, additional, Pelletier, Keith, additional, and White, Lori, additional

Published
2021
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50. An immediate access dialysis graft designed to prevent needle-related complications: Results from the initial pre-clinical studies

Author

Dalton Sycks, Knight Joseph, Lawson Michael, Craig Nichols, Roberto J. Manson, and Shawn M. Gage

Subjects
medicine.medical_specialty, Time Factors, medicine.medical_treatment, Sus scrofa, Vascular access, Hemodialysis, Home, Prosthesis Design, Article, Catheterization, Blood Vessel Prosthesis Implantation, Arteriovenous Shunt, Surgical, Materials Testing, medicine, Animals, Intensive care medicine, Dialysis, Sheep, Domestic, Vascular Patency, business.industry, Blood Vessel Prosthesis, Prosthesis Failure, surgical procedures, operative, Nephrology, Needles, Models, Animal, Abandonment (emotional), Feasibility Studies, Surgery, Female, business
Abstract

Introduction: No technology has been specifically developed with the intent to reduce needle-related vascular access injuries; a significant source of complications and abandonment. We present the initial pre-clinical study results of a novel, self-sealing, immediate cannulation dialysis graft that aims to prevent needle-related complications; to promote safe, reliable needle access; to reduce catheter use; and could facilitate home hemodialyisis. Methods: The innovative graft design consists of two cannulation chambers with self-sealing properties and materials that prevent side and back wall needle puncture. Study and control grafts (expanded polytetrafluoroethylene) were implanted in one pig and 10 sheep in two studies over the course of 1 year. First cannulation occurred immediately post implant for all study grafts. Post-cannulation time to hemostasis, hematoma and seroma formation, infection, and patency were recorded. Results: The two studies account for nearly 60 weeks (average 6.4 weeks/graft) of study graft follow-up. In the ovine study, average study graft time to hemostasis was 27.3 s (standard deviation = 26.3, range = 0–120), and the control averaged 177.2 s (standard deviation = 113.4, range = 60–600), p Discussion: All novel grafts in the studies were implanted successfully and functioned as intended. There were no complications related to tunneling of the study graft and the chamber prevented back/side wall needle injury. This novel technology may help to mitigate these needle-related complications, while allowing for early/immediate cannulation which could also reduce catheter contact time.

Published
2019

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