Digital Commons Network^™

The Future Of Zoonotic Risk Prediction, Colin J. Carlson, Maxwell J. Farrell, Zoe Grange, Barbara A. Han, Nardus Mollentze, Alexandra L. Phelan, Angela L. Rasmussen, Gregory F. Albery, Bernard Bett, David M. Brett-Major, Lily E. Cohen, Tad Dallas, Evan A. Eskew, Anna C. Fagre, Kristian M. Forbes, Rory Gibb, Sam Halabi, Charlotte C. Hammer, Rebecca Katz, Jason Kindrachuk, Renata L. Muylaert, Felicia B. Nutter, Joseph Ogola, Kevin J. Olival, Michelle Rourke, Sadie J. Ryan, Noam Ross, Stephanie N. Seifert, Tarja Sironen, Claire J. Standley, Kishana Taylor, Marietjie Venter, Paul W. Webala

Faculty Publications

In the light of the urgency raised by the COVID-19 pandemic, global investment in wildlife virology is likely to increase, and new surveillance programmes will identify hundreds of novel viruses that might someday pose a threat to humans. To support the extensive task of laboratory characterization, scientists may increasingly rely on data-driven rubrics or machine learning models that learn from known zoonoses to identify which animal pathogens could someday pose a threat to global health. We synthesize the findings of an interdisciplinary workshop on zoonotic risk technologies to answer the following questions. What are the prerequisites, in terms of open …

Patterns And Trends Of Organic Matter Processing And Transport: Insights From The Us Long-Term Ecological Research Network, Tamara K. Harms, Peter M. Groffman, Lihini Aluwihare, Christopher Craft, William R. Wieder, Sarah E. Hobbie, Sara G. Baer, John M. Blair, Serita D. Frey, Christina K. Remucal, Jennifer A. Rudgers, Scott L. Collins, John S. Kominoski, Becky A. Ball, Lter Om Working Group

Faculty Publications

Organic matter (OM) dynamics determine how much carbon is stored in ecosystems, a service that modulates climate. We synthesized research from across the US Long-Term Ecological Research (LTER) Network to assemble a conceptual model of OM dynamics that is consistent with inter-disciplinary perspectives and emphasizes vulnerability of OM pools to disturbance. Guided by this conceptual model, we identified unanticipated patterns and long-term trends in processing and transport of OM emerging from terrestrial, freshwater, wetland, and marine ecosystems. Cross-ecosystem synthesis combined with a survey of researchers revealed several themes: 1) strong effects of climate change on OM dynamics, 2) surprising patterns …

Moving On Up: Vertical Distribution Shifts In Rocky Reef Fish Species During Climate-Driven Decline In Dissolved Oxygen From 1995 To 2009, Erin L. Meyer-Gutbrod, Li Kui, Mary Nishimoto, Linda Snook, Milton Love

Faculty Publications

Anthropogenic climate change has resulted in warming temperatures and reduced oxygen concentrations in the global oceans. Much remains unknown on the impacts of reduced oxygen concentrations on the biology and distribution of marine fishes. In the Southern California Channel Islands, visual fish surveys were conducted frequently in a manned submersible at three rocky reefs between 1995 and 2009. This area is characterized by a steep bathymetric gradient, with the surveyed sites Anacapa Passage, Footprint and Piggy Bank corresponding to depths near 50, 150 and 300 m. Poisson models were developed for each fish species observed consistently in this network of …

Cognition-Enhanced Machine Learning For Better Predictions With Limited Data, Florian Sense, Ryan Wood, Michael G. Collins, Joshua Fiechter, Aihua W. Wood, Michael Krusmark, Tiffany Jastrzembski, Christopher W. Myers

Faculty Publications

The fields of machine learning (ML) and cognitive science have developed complementary approaches to computationally modeling human behavior. ML's primary concern is maximizing prediction accuracy; cognitive science's primary concern is explaining the underlying mechanisms. Cross-talk between these disciplines is limited, likely because the tasks and goals usually differ. The domain of e-learning and knowledge acquisition constitutes a fruitful intersection for the two fields’ methodologies to be integrated because accurately tracking learning and forgetting over time and predicting future performance based on learning histories are central to developing effective, personalized learning tools. Here, we show how a state-of-the-art ML model can …

Gap-Filling Of 8-Day Terra Modis Daytime Land Surface Temperature In High-Latitude Cold Region With Generalized Additive Models (Gam), Dianfan Guo, Cuizhen Wang, Shuying Zang, Jinxi Hua, Zhenghan Lv, Yue Lin

Faculty Publications

Land surface temperature (LST) is a crucial parameter driving the dynamics of the thermal state on land surface. In high-latitude cold region, a long-term, stable LST product is of great importance in examining the distribution and degradation of permafrost under pressure of global warming. In this study, a generalized additive model (GAM) approach was developed to fill the missing pixels of the MODIS/Terra 8-day Land Surface Temperature (MODIS LST) daytime products with the ERA5 Land Skin Temperature (ERA5ST) dataset in a high-latitude watershed in Eurasia. Comparison at valid pixels revealed that the MODIS LST was 4.8–13.0 °C higher than ERA5ST, …

Modeling Of Mos2 Tunnel Field Effect Transistor In Verilog-A For Vlsi Circuit Design, Md Azmot Ullah Khan, Naheem Olakunle Adesina, Jian Xu

Faculty Publications

This paper presents the design of an inverter, half adder, and ring oscillator using compact models of MoS2 channel-based tunnel field effect transistor (TFET). The TFET models (both nand p-type) are written in high-level hardware language Verilog-Analog (Verilog-A) following the analytical model of [1] and the output characteristics of the components are simulated in Cadence/Spectre software. The performance of the designed inverter (a basic building block of VLSI circuit) is analyzed by extracting its different parameters, such as transfer characteristics, power dissipation and consumption, delay, power delay product. The simulated outputs (sum carry) obtained from the half adder circuit exactly …

Automated Drone Detection Using Yolov4, Subroto Singha, Burchan Aydin

Faculty Publications

Drones are increasing in popularity and are reaching the public faster than ever before. Consequently, the chances of a drone being misused are multiplying. Automated drone detection is necessary to prevent unauthorized and unwanted drone interventions. In this research, we designed an automated drone detection system using YOLOv4. The model was trained using drone and bird datasets. We then evaluated the trained YOLOv4 model on the testing dataset, using mean average precision (mAP), frames per second (FPS), precision, recall, and F1-score as evaluation parameters. We next collected our own two types of drone videos, performed drone detections, and calculated the …

Small Studies, Big Decisions: The Role Of Pilot/Feasibility Studies In Incremental Science And Premature Scale-Up Of Behavioral Interventions, Michael William Beets, Lauren Von Klinggraeff, Robert G. Weaver, Bridget Ryan Armstrong, Sarah Burkart

Faculty Publications

Background: Careful consideration and planning are required to establish “sufficient” evidence to ensure an investment in a larger, more well-powered behavioral intervention trial is worthwhile. In the behavioral sciences, this process typically occurs where smaller-scale studies inform larger-scale trials. Believing that one can do the same things and expect the same outcomes in a larger-scale trial that were done in a smaller-scale preliminary study (i.e., pilot/feasibility) is wishful thinking, yet common practice. Starting small makes sense, but small studies come with big decisions that can influence the usefulness of the evidence designed to inform decisions about moving forward with a …

A Southwestern United States Pilot Investigation Of Triatomine–Mite Prevalence, Kyndall C. Dye-Braumuller, Hanna Waltz, Mary K. Lynn, Stephen A. Klotz, Justin O. Schmidt, Alvaro Romero, Marvin Stanley Rodriguez Aquino, Jose Ricardo Palacios Valladares, Pamela Michelle Cornejo Rivas, Melissa Nolan Ph.D., Mph

Faculty Publications

An estimated 70 million persons in the Western Hemisphere are living at risk for Chagas disease, a parasitic infection transmitted to humans by over 156 different competent triatomine insect vector species. Prior Pan American Health Organization insecticide campaigns throughout Latin America in the 1990s and 2000s demonstrated that domestic insecticide spraying had temporary effects, which resulted in the re-establishment of triatomine species within a few years. Serendipitously, our team found ectoparasitic mites parasitizing triatomines collected from the field in multiple locations in the southwestern United States, where human–triatomine interaction was high but human parasite infection remains low. Upon further investigation …

Erratum: Searches For Continuous Gravitational Waves From Nine Young Supernova Remnants (Apj (2015) 813 (39) Doi: 10.1088/0004-637x/813/1/39), J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, A. Ain, P. Ajith, Tiffany Z. Summerscales

Faculty Publications

Equation (7) of the published article (Aasi et al. 2015) is in error; it should read (Equation presented). The upper limits on ò presented in the published article are unaffected by this error. Equation (8) of the published article is in error; it should read (Equation presented) The upper limits on α presented in Figure 3 and Table 4 of the published article were computed incorrectly. The revised Figure 3 (bottom) shows the corrected upper limits on α for the G266.2-1.2 (Vela Jr.) wide search. The revised Table 4 is provided here. The correct lowest upper limit on α (quoted …

Maternal Diet In Pregnancy And Child’S Respiratory Outcomes: An Individual Participant Data Meta-Analysis Of 18 000 Children, Sara M. Mensink-Bout, Evelien R. Van Meel, Johan C. De Jongste, Isabella Annesi-Maesano, Adrien M. Aubert, Jonathan Y. Bernard, Ling-Wei Chen, Cyrus Cooper, Sarah R. Crozier, Wojciech Hanke, Nicholas C. Harvey, James R. Hébert Scd, Barbara Heude, Joanna Jerzynska, Cecily C. Kelleher, John Mehegan, Fionnuala M. Mcauliffe, Catherine M. Phillips, Kinga Polanska, Caroline L. Relton, Nitin Shivappa Mbbs, Mph, Ph.D., Matthew Suderman, Vincent W.V. Jaddoe, Liesbeth Duijts

Faculty Publications

Rationale Severe fetal malnutrition has been related to an increased risk of respiratory diseases later in life, but evidence for the association of a suboptimal diet during pregnancy with respiratory outcomes in childhood is conflicting. We aimed to examine whether a pro-inflammatory or low-quality maternal diet during pregnancy was associated with child's respiratory health.

Methods We performed an individual participant meta-analysis among 18 326 mother–child pairs from seven European birth cohorts. Maternal pro-inflammatory and low-quality diets were estimated by energy-adjusted Dietary Inflammatory Index (E-DII) and Dietary Approaches to Stop Hypertension (DASH) scores. Preschool wheezing and school-age asthma were measured using …

Dynamic Simulation Of A Novel Nuclear Hybrid Energy System With Large-Scale Hydrogen Storage In An Underground Salt Cavern, An Ho, Kasra Mohammadi, Matthew Memmott, John Hedengren, Kody Powell

Faculty Publications

In this study, a nuclear hybrid energy system (NHES) with large-scale hydrogen storage integrated with a gas turbine cycle is proposed as a flexible system for load following. The proposed system consists of a nuclear reactor, a steam Rankine cycle, a hydrogen electrolyzer, a storage system for hydrogen in an underground salt cavern, and a Brayton cycle that uses hydrogen as fuel to generate additional electricity to meet peak demand. A dynamic mathematical model is developed for each subsystem of the NHES. To evaluate the potential benefits of the system, a one-year study is conducted, using scaled grid demand data …

Application Of Stoichiometric Hydrogen Atoms For Balancing Organic Combustion Reactions, Pong Kau Yuen, Cheng Man Diana Lau

Faculty Publications

Combustion is a common redox reaction, and organic combustion is one of the basic contents in chemistry curriculum. The transferred H-atom is commonly used as a redox indicator in organic chemistry and biochemistry. Nevertheless, the relationship between the number of transferred H-atoms and the number of transferred electrons has not been fully revealed. Oxidation number (ON) is an electron-counting concept. Without knowing the ONs, the number of transferred electrons cannot be counted and therefore, the redox reactions cannot be classified, defined, and balanced. This paper explores the new H-atom method for counting the number of transferred H-atoms. It provides a …

Biogeochemical And Hydrological Variables Synergistically Influence Nitrate Variability In Coastal Deltaic Wetlands, Alicia Sendrowski, Edward Castañeda-Moya, Robert Twilley, Paola Passalacqua

Faculty Publications

Coastal river deltas are centers of surface water nitrate processing, yet the mechanisms controlling spatio-temporal patterns in nutrient variability are still little understood. Nitrate fluctuations in these systems are controlled by complex interactions between hydrological and biogeochemical drivers, which act together to transport and transform inorganic nutrients. Distinguishing the contributions of these drivers and identifying wetland zones where nitrate processing is occurring can be difficult, yet is critical to make assessments of nutrient removal capacity in deltaic wetlands. To address these issues, we analyze relationships among regional “external” (river discharge, tides, wind) and local “internal” (water level, temperature, turbidity, and …

An Integrated Energy Simulation Model Of A Compressed Air System For Sustainable Manufacturing: A Time‐Discretized Approach, Vansh Vyas, Hyun Woo Jeon, Chao Wang

Faculty Publications

A compressed air system (CAS) is one of the most common and energy‐consuming systems in manufacturing. To practice more economically and environmentally sustainable manufacturing, manufacturers need ways to reduce the energy costs and carbon footprint, resulting from a CAS in their production systems. While preliminary energy studies on a CAS and on machining processes are available separately, existing research studies rarely analyze energy costs using a tool that considers both a CAS and production systems. Therefore, in this study, we propose an energy simulation tool that combines a CAS and a production system to evaluate the effects of a CAS …

An Earth-Mass Planet In A Time Of Covid-19: Kmt-2020-Blg-0414lb, Weicheng Zang, Cheongho Han, Iona Kondo, Jennifer C. Yee, Chung Uk Lee, Andrew Gould, Shude Mao, Leandro De Almeida, Yossi Shvartzvald, Xiangyu Zhang, Michael D. Albrow, Sun Ju Chung, Kyu Ha Hwang, Youn Kil Jung, Yoon Hyun Ryu, In Gu Shin, Sang Mok Cha, Dong Jin Kim, Hyoun Woo Kim, Seung Lee Kim, Dong Joo Lee, Yongseok Lee, Byeong Gon Park, Richard W. Pogge, John Drummond, Thiam Guan Tan, José Dias Do Nascimento, Dan Maoz, Matthew T. Penny, Wei Zhu, Ian A. Bond, Fumio Abe, Richard Barry

Faculty Publications

We report the discovery of KMT-2020-BLG-0414Lb, with a planet-to-host mass ratio q2 = 0:9- 1:2 × 10-5 = 3-4 q⊕ at 1σ, which is the lowest mass-ratio microlensing planet to date. Together with two other recent discoveries (4. q=q⊕. 6), it fills out the previous empty sector at the bottom of the triangular (log s; log q) diagram, where s is the planet-host separation in units of the angular Einstein radius θE. Hence, these discoveries call into question the existence, or at least the strength, of the break in the mass-ratio function that was previously suggested to account for the …

A Tale Of Two Representations: Energy And Time In Photoabsorption, A. R.P. Rau

Faculty Publications

This essay is based on a talk at Advances in Atomic, Molecular, and Optical Sciences 2020 (AAMOS20) in a symposium honoring Prof. S. T. Manson's decades-long contribution to photoabsorption studies. Quantum physics introduced into physics pairs of conjugate quantities bearing a specific complementary relationship, energy and time being one such pair. This gives rise to two alternative representations, a time-dependent and a time-independent one, seemingly very different but both capable of embracing the same physics. They give complementary descriptions and insight, with technical questions, theoretical and experimental, determining which may be the more convenient and practicable at any juncture. Two …

Symmetries And Geometries Of Qubits, And Their Uses, A. R.P. Rau

Faculty Publications

The symmetry SU(2) and its geometric Bloch Sphere rendering have been successfully applied to the study of a single qubit (spin-1/2); however, the extension of such symmetries and geometries to multiple qubits—even just two—has been investigated far less, despite the centrality of such systems for quantum information processes. In the last two decades, two different ap-proaches, with independent starting points and motivations, have been combined for this purpose. One approach has been to develop the unitary time evolution of two or more qubits in order to study quantum correlations; by exploiting the relevant Lie algebras and, especially, sub-algebras of the …

Directly Determined Properties Of Hd 97658 From Interferometric Observations, Tyler G. Ellis, Tabetha Boyajian, Kaspar Von Braun, Roxanne Ligi, Denis Mourard, Diana Dragomir, Gail H. Schaefer, Christopher D. Farrington

Faculty Publications

We conducted interferometric observations with the CHARA Array of transiting super-Earth host HD 97658 and measured its limb-darkened angular diameter to be theta(LD) = 0.314 +/- 0.004 mas. The combination of the angular diameter with the Gaia EDR3 parallax value with zero-point correction (pi = 46.412 +/- 0.022 mas, d =21.546 +/- 0.011 pc) yields a physical radius of R-star = 0.728 +/- 0.008 R-circle dot. We also measured the bolometric flux of the star to be F-bol = 2.42 +/- 0.05 x 10(-8) erg s(-1) cm(-2), which, together with angular size, allows a measurement of the effective temperature T-eff …

Global Flash Drought Monitoring Using Surface Soil Moisture, Vinit Sehgal, Nandita Gaur, Binayak P. Mohanty

Faculty Publications

Abrupt onset and swift intensification characterize flash droughts. Global surface soil moisture (θRS) from NASA's Soil Moisture Active Passive (SMAP) satellite can facilitate a near-real-time assessment of emerging flash droughts at a 36-km footprint. However, a robust flash drought monitoring using θRS must account for the (a) short observation record of SMAP, (b) nonlinear geophysical controls over θRS dynamics, and (c) emergent meteorological drivers of flash droughts. We propose a new method for near-real-time characterization of droughts using Soil Moisture Stress (SMS, drought stress) and Relative Rate of Drydown (RRD, drought stress intensification rate)—developed using SMAP θRS (March 2015–May 2021), …

Fourth-Order Adjoint Sensitivity And Uncertainty Analysis Of An Oecd/Nea Reactor Physics Benchmark: I. Computed Sensitivities, Ruixian Fang, Dan Gabriel Cacuci

Faculty Publications

This work extends the investigation of higher-order sensitivity and uncertainty analysis from 3rd-order to 4th-order for a polyethylene-reflected plutonium (PERP) OECD/NEA reactor physics benchmark. Specifically, by applying the 4th-order comprehensive adjoint sensitivity analysis methodology (4th-CASAM) to the PERP benchmark, this work presents the numerical results of the most important 4th-order sensitivities of the benchmark’s total leakage response with respect to the benchmark’s 180 microscopic total cross sections, which includes 180 4th-order unmixed sensitivities and 360 4th-order mixed sensitivities corresponding to the largest 3rd-order ones. The numerical results obtained in this work reveal that the number of 4th-order relative sensitivities that …

Prevalence, Awareness, And Control Of Hypertension Among Bangladeshi Adults: An Analysis Of Demographic And Health Survey 2017-18, Gulam Muhammed Al Kibria, Rajat Das Gupta Ph.D., Jannatun Nayeem

Faculty Publications

Background

The prevalence of hypertension is increasing in Bangladesh, however, few recent studies investigated the proportion of people and factors associated with prevalence, awareness, and control of this condition in this country. This study investigated these among Bangladeshi adults.

Methods

Using Bangladesh Demographic and Health Survey 2017–18 data, a cross-sectional study was conducted. Multilevel logistic regression analysis was employed after descriptive analysis and prevalence estimation.

Results

Among 12,926 persons (mean age: 40 years, 57% women), the prevalence of hypertension was 27.4% (n = 3551), it was 28.4 and 26.2% among females and males, respectively. Among hypertensive people, about 42.4% …

Robust Method Of Determining Microfacet Brdf Parameters In The Presence Of Noise Via Recursive Optimization, Michael W. Bishop, Samuel D. Butler, Michael A. Marciniak

Faculty Publications

Accurate bidirectional reflectance distribution function (BRDF) models are essential for computer graphics and remote sensing performance. The popular microfacet class of BRDF models is geometric-optics-based and computationally inexpensive. Fitting microfacet models to scatterometry measurements is a common yet challenging requirement that can result in a model being fit as one of several unique local minima. Final model fit accuracy is therefore largely based on the quality of the initial parameter estimate. This makes for widely varying material parameter estimates and causes inconsistent performance comparisons across microfacet models, as will be shown with synthetic data. We proposed a recursive optimization method …

Data-Driven Algorithm To Classify The Degree Of Isotropy In The Bidirectional Reflectance Distribution Function, Anne W. Werkley, Samuel D. Butler, Todd V. Small, Michael A. Marciniak

Faculty Publications

The bidirectional reflectance distribution function (BRDF) is used to describe reflectances of materials by calculating the ratio of the reflected radiance to the incident irradiance. While it was found that the isotropic models maintained symmetry about ϕ_s  =  π, such symmetry was not maintained about the θ_s  =  θ_i axis, except for close to the specular peak. This led to the development of a data-driven metric for how isotropic a BRDF measurement is. Research efforts centered around developing an algorithm that could determine material anisotropy without having to fit to models. This algorithm was tested using high …

The Impact Of Laser Control On The Porosity And Microstructure Of Selective Laser Melted Nickel Superalloy 718, Travis E. Shelton, Gregory R. Cobb, Carl R. Hartsfield, Benjamin M. Doane, Cayla C. Eckley, Ryan A. Kemnitz

Faculty Publications

Additively manufacturing high performance metals by laser processing represents an exciting opportunity to exploit localized properties by varying input parameters throughout the process. This work explores the solidification and microstructural properties of selectively laser melted (SLM) Inconel 718 (IN718) using unique processing parameters. By employing traditional pulsed laser physics techniques, samples were manufactured with a continuous wave laser to study a potential ubiquitous approach. While the overall power density was controlled, the power, speed, and hatch spacing were varied. The porosity and grain sizes of the samples were characterized by optical and scanning electron microscopes. The influence of processing parameters …

Evaluating The Vulnerability Of Farming Communities To Winter Storms In Iowa, Us, Yiyi Zhang, Bingquing Liang

Faculty Publications

Winter storms have been reported as the second-most frequent catastrophe in the Midwest of the United States and can create non-negligible impacts on farming communities that highly rely on climatic-sensitive resources and activities. However, few studies have attempted to assess the vulnerability to winter storms in rural contexts. Focusing on all counties in Iowa, US, as the study area, this research aimed to evaluate the vulnerability of farming communities to winter storms and its major determinants. It first identified both climatic and non-climatic indicators for quantifying winter storm exposure, sensitivity, and adaptive capacity by reviewing previous related studies and examining …

Ocean Regime Shift Is Driving Collapse Of The North Atlantic Right Whale Population, Erin L. Meyer-Gutbrod, Charles H. Greene, Kimberley T.A. Davies, David G. Johns

Faculty Publications

Ocean warming linked to anthropogenic climate change is impacting the ecology of marine species around the world. In 2010, the Gulf of Maine and Scotian Shelf regions of the Northwest Atlantic underwent an unprecedented regime shift. Forced by climate-driven changes in the Gulf Stream, warm slope waters entered the region and created a less favorable foraging environment for the endangered North Atlantic right whale population. By mid-decade, right whales had shifted their late spring/summer foraging grounds from the Gulf of Maine and the western Scotian Shelf to the Gulf of St. Lawrence. The population also began exhibiting unusually high …

Bright And Blind Spots Of Water Research In Latin America And The Caribbean, Alyssa J. Devincentis, Hervé Guillon, Romina Díaz Gómez, Noelle K. Patterson, Francine Van Den Brandeler, Srthur Koehl, Pablo Ortiz-Partida, Laura E. Garza-Díaz, Jennifer Gamez-Rodríguez, Erfan Goharian, Samuel Sandoval Solis

Faculty Publications

Water resources management in Latin America and the Caribbean is particularly threatened by climatic, economic, and political pressures. To assess the region's ability to manage water resources, we conducted an unprecedented literature review of over 20 000 multilingual research articles using machine learning and an understanding of the socio-hydrologic landscape. Results reveal that the region's vulnerability to water-related stresses, and drivers such as climate change, is compounded by research blind spots in niche topics (reservoirs and risk assessment) and subregions (Caribbean nations), as well as by its reliance on an individual country (Brazil). A regional bright spot, Brazil, produces well-rounded …

Microbial Activity Responses To Water Stress In Agricultural Soils From Simple And Complex Crop Rotations, Jorg Schnecker, D. Boone Meeden, Francisco Calderon, Michel Cavigelli, R. Michael Lehman, Lisa K. Tiemann, A. Stuart Grandy

Faculty Publications

Increasing climatic pressures such as drought and flooding challenge agricultural systems and their management globally. How agricultural soils respond to soil water extremes will influence biogeochemical cycles of carbon and nitrogen in these systems. We investigated the response of soils from long-term agricultural field sites under varying crop rotational complexity to either drought or flooding stress. Focusing on these contrasting stressors separately, we investigated soil heterotrophic respiration during single and repeated stress cycles in soils from four different sites along a precipitation gradient (Colorado, MAP 421 mm; South Dakota, MAP 580 mm; Michigan, MAP 893 mm; Maryland, MAP 1192 mm); …

Encirclement Of Moving Targets Using Noisy Range And Bearing Measurements, Cammy Peterson, Puneet Jain, Randal Beard

Faculty Publications

This paper presents theoretically justified controllers that use relative range and bearing measurements to steer a team of autonomous vehicles, operating without inertial position information, to circular trajectories around a constant-acceleration, constant-velocity, or stationary target. An extended Kalman filter is used to improve the noisy relative measurements and estimate the velocity of the moving target. These estimated values are used in the control laws to encircle constant-velocity moving targets. Lyapunov techniques are utilized to show that the vehicle will converge to the desired circular formations. Additionally, cooperating vehicles are shown to converge to a circular formation with equal temporal spacing …