Digital Commons Network^™

The Roles Of Vicarious Trauma Exposure And Perceived Social Support In Codeine Syrup Misuse Among Black Men Living In Prisons, Jardin Dogan-Dixon, Shawndaya S. Thrasher, Shemeka Thorpe, Paris Wheeler, Danelle Stevens-Watkins

Faculty Publications

Using General Strain Theory, this study investigates the effects of vicarious trauma exposure and perceived social support on nonmedical codeine syrup misuse among Black incarcerated men nearing community re-entry. Data were drawn from the Helping Incarcerated Men project, a study examining mental health, substance misuse, and human immunodeficiency virus (HIV) risk behaviors among Black men living in prisons who were within 180 days of release. A total of 200 Black men self-reported demographics (i.e., age and length of incarceration after age 18), vicarious trauma exposure (e.g., ever witnessing an assault with a weapon and a sudden accidental death), perceived social …

Deephive: A Reinforcement Learning Approach For Automated Discovery Of Swarm-Based Optimization Policies, Eloghosa Ikponmwoba, Opeoluwa Owoyele

Faculty Publications

We present an approach for designing swarm-based optimizers for the global optimization of expensive black-box functions. In the proposed approach, the problem of finding efficient optimizers is framed as a reinforcement learning problem, where the goal is to find optimization policies that require a few function evaluations to converge to the global optimum. The state of each particle within the swarm is defined as its current position and function value within a design space, and the particles learn to take favorable actions that maximize the reward, which is based on the final value of the objective function. The proposed approach …

Research Gaps And Priorities For Quantitative Microbial Risk Assessment (Qmra), Kerry A. Hamilton, Joanna Ciol Harrison, Jade Mitchell, Mark Weir, Marc Verhougstraete, Charles N. Haas, A. Pouyan Nejadhashemi, Julie Libarkin, Tiong Gim Aw, Kyle Bibby, Aaron Bivins, Joe Brown, Kara Dean, Gwyneth Dunbar, Joseph N.S. Eisenberg, Monica Emelko, Daniel Gerrity, Patrick L. Gurian, Emma Hartnett, Michael Jahne, Rachael M. Jones, Timothy R. Julian, Hongwan Li, Yanbin Li, Jacqueline Mac Donald Gibson, Gertjan Medema, J. Scott Meschke, Alexis Mraz, Heather Murphy, David Oryang, Emmanuel De Graft Johnson Owusu-Ansah, Emily Pasek, Abani K. Pradhan

Faculty Publications

The coronavirus disease 2019 pandemic highlighted the need for more rapid and routine application of modeling approaches such as quantitative microbial risk assessment (QMRA) for protecting public health. QMRA is a transdisciplinary science dedicated to understanding, predicting, and mitigating infectious disease risks. To better equip QMRA researchers to inform policy and public health management, an Advances in Research for QMRA workshop was held to synthesize a path forward for QMRA research. We summarize insights from 41 QMRA researchers and experts to clarify the role of QMRA in risk analysis by (1) identifying key research needs, (2) highlighting emerging applications of …

Computational Modeling Of Tool-Rock Frictional Contact With Anisotropic Damage, Yaneng Zhou, George Z. Voyiadjis

Faculty Publications

The mechanism of frictional contact is investigated between a blunt tool and quasi-brittle rocks with anisotropic damage. A recently developed anisotropic elasto-plastic-damage model is further validated using experimental results under monotonic and cyclic loadings for rocks and concrete. A finite element model of tool-rock frictional contact is validated by analytical results in the two asymptotic regimes of an elastoplastic rock. The mesh sensitivity is reduced using a fracture energy-based method for anisotropic damage. The tool-rock frictional contact is predominantly controlled by three dimensionless parameters: η, ξ, and ζ, which characterize elastoplasticity, brittleness, and anisotropic damage, respectively. The newly introduced damage …

Global Empirical Model Of Sporadic-E Occurrence Rates, Eli V. Parsch, Anthony L. Franz, Eugene V. Dao, Dong L. Wu, Nimalan Swarnalingam, Cornelius C. J. H. Salinas, Daniel J. Emmons

Faculty Publications

Intense ionization enhancements in the Earth’s ionosphere, known as sporadic-E (E_s), can degrade and severely disrupt the propagation of radio signals. Although many previous studies have analyzed the characteristics and morphologies of sporadic-E, few efforts have attempted to model global E_s occurrence rates (ORs) at high time resolutions. This study develops a global empirical model of blanketing sporadic-E occurrence rates using a Karhunen–Loéve Expansion (KLE) of a global OR climatology built with Global Navigation Satellite System radio occultation (GNSS-RO) and ionosonde observations. Using an fbE ≥ threshold of 3 MHz, the model outputs a blanketing sporadic-E …

Privacy Law's Incumbency Problem, Peter Ormerod

Faculty Publications

Policymakers and scholars concerned with the power of informational platforms are questioning how traditional doctrinal silos like privacy law and antitrust law interact in digital markets. Their interaction has taken on new urgency in recent years as states have enacted a flurry of consent-based privacy laws and as digital markets have become increasingly dominated by the same few firms

Contemporary debates about the interaction of competition and privacy tend to ask what role, if any, privacy should play in the antitrust analysis. Little has been written about how new privacy laws shape the competitive landscape. This Article argues that consent-based …

The Power Of All: Tort In The Age Of Constitution, Cristina Carmody Tilley

Faculty Publications

Life in a multicultural nation can be fraught. The United States is a case in point, with hostile tension between members of competing identity groups playing out today on streets, in offices, and across the media. Modern Americans assume that bridging race, gender, and class inequity is the stuff of public—constitutional—law. This assumption follows the lead of modern American lawyers, who migrated to this body of law just as historians, sociologists, and economists began to insist that the private law of tort was exclusively concerned with the accidental physical harms inevitable in a modern economy. According to this econostory, tort …

Variations Of Aquaculture Structures, Operations, And Maintenance With Increasing Ocean Energy, Kevin G. Heasman, Nicholas Scott, Tyler Sclodnick, Michael Chambers, Barry Costa-Pierce, Tobias Dewhurst, Wolf Isbert, Bela H. Buck

Faculty Publications

Aquaculture in exposed and/or distant ocean sites is an emerging industry and field of study that addresses the need to improve food security along with the challenges posed by expansion of urban and coastal stakeholders into nearshore and sheltered marine waters. This move necessitates innovative solutions for this industry to thrive in high-energy environments. Some innovative research has increased understanding of the physics, hydrodynamics, and structural requirements enabling the development of appropriate systems. The blue mussel (Mytilus edulis), the New Zealand green shell or green lipped mussel (Perna canaliculus), and the Pacific Oyster (Magallana gigas), are the primary targets for …

Variations Of Aquaculture Structures, Operations, And Maintenance With Increasing Ocean Energy, Kevin G. Heasman, Nicholas Scott, Tyler Sclodnick, Michael Chambers, Barry Costa-Pierce, Tobias Dewhurst, Wolf Isbert, Bela H. Buck

Faculty Publications

Aquaculture in exposed and/or distant ocean sites is an emerging industry and field of study that addresses the need to improve food security along with the challenges posed by expansion of urban and coastal stakeholders into nearshore and sheltered marine waters. This move necessitates innovative solutions for this industry to thrive in high-energy environments. Some innovative research has increased understanding of the physics, hydrodynamics, and structural requirements enabling the development of appropriate systems. The blue mussel (Mytilus edulis), the New Zealand green shell or green lipped mussel (Perna canaliculus), and the Pacific Oyster (Magallana gigas), are the primary targets for …

How Do Scholars Conceptualize And Conduct Health And Digital Health Literacy Research? Survey Of Federally Funded Scholars, Mayank Sakhuja, Brooks Yelton Ma, Lmsw, Simone Kabarana, Lauren Schaurer, Jancham Rachel Rumthao, Samuel Noblet, Michelle Angelique Arent, Mark M. Macauda Phd, Mph, Lorie Donelle Phd, Rn, Fcan, Daniela B. Friedman Ph.D.

Faculty Publications

Background: The concept of health literacy (HL) is constantly evolving, and social determinants of health (SDoH) have been receiving considerable attention in public health scholarship. Since a 1-size-fits-all approach for HL fails to account for multiple contextual factors and as a result poses challenges in improving literacy levels, there is a need to develop a deeper understanding of the current state of HL and digital health literacy (DHL) research. Objective: This study examined scholars’ conceptualization and scope of work focused on HL and DHL. Methods: Using a search string, investigators (N=2042) focusing on HL, DHL, or both were identified from …

The Impact Of Film Cooling On The Heat Release Within A Rotating Detonation Combustor, Shreyas Ramanagar Sridhara, Antonio Andreini, Marc D. Polanka, Myles D. Bohon

Faculty Publications

Rotating detonation combustors establish a detonation wave that continuously circulates inside a small annulus. The presence of the detonation wave and the downstream oblique shock within the small annulus coupled with high mass flow induces a high heat load to the combustor wall. Preliminary analysis shows that for higher thermal power, internal air cooling alone is not sufficient to remove the heat out of the walls to maintain them below the maximum temperature of the metal. A possible solution is to use film cooling to reduce the heat flux to the combustor walls. One issue, though, is that the introduction …

The Structure, Oxidation States, And Energetics Of Co Nanoparticles On Ceo2(111): An Stm And Dft Study, Md Saeedur Rahman, Nishan Paudyal, Linze Du Hill, Jing Zhou, Ye Xu

Faculty Publications

Co nanoparticles (NPs) dispersed on ceria have been widely studied as active catalytic materials for many industrially relevant reactions. The detailed nature of such particles and the factors affecting their interaction with ceria remain to be better understood. In this study, a very low coverage (∼0.02 ML) of Co is deposited on a model CeO2(111) thin-film surface and is examined using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). The Co NPs that nucleate on terrace sites grow with coverage in this range to a maximum size of ca. 40 Co atoms, with an average diameter and height of …

Modeling Reversible Volume Change In Automotive Battery Cells With Porous Silicon Oxide-Graphite Composite Anodes, Taylor R. Garrick, Brian J. Koch, Miguel A. Fernandez, Erin Efimoff, Hunter Teel, Matthew D. Jones, Mingjie Tu, Sirivatch Shimpalee

Faculty Publications

Automotive battery manufacturers are working to improve the individual cell and overall pack design by increasing durability, performance, and range, while reducing cost, and active material volume change is a key aspect that needs to be considered during this design process. Recently, silicon oxide-graphite composite anodes are being explored to increase total anode capacity while maintaining a tolerable amount of cell level reversible volume expansion due to the relatively lower reversible volume change of the silicon oxide compared to pure battery grade or metallurgical grade silicon. To predict the blended anode response and contribution to the overall cell volume change, …

Oyster Grower Perspectives On Green Crab (Carcinus Maenas) Interactions: Using Applied Social Science To Inform Research And Engagement, Kelsey Meyer-Rust, Lindsey Williams, Krystin Ward, Bonnie Brown

Faculty Publications

Research that informs the New Hampshire Aquaculture industry, which has grown significantly over the past few years, and helps the overall associated watershed community to keep Great Bay Estuary healthy is vital. Specific study of green crabs, Carcinus maenas, and their potential effects on oysters, Crassostrea virginica, is important to gain a better understanding of the impact invasive species may have on these ecologically and economically important bivalves. The aim of this study was to document and understand New Hampshire (NH) oyster growers’ perspectives on the issue of green crab predation of oysters. Through a survey, this study documented a …

Evaluation And Lessons Learned From The Dissemination And Implementation Science Scholars Program In The National Cancer Prevention And Control Research Network, Daniela B. Friedman, Cam Escoffery, Elaine H. Morrato, Cynthia A. Thomson, Courtney N. Petagna, Freda Allyson Hucek, Mary Wangen, Aubrey Villalobos, James R. Hébert Scd, Samuel Noblet, Mayank Sakhuja, David O. Garcia, Jennifer L. Cruz, Stephanie B. Wheeler

Faculty Publications

Background:

The Centers for Disease Control and Prevention (CDC)-funded Cancer Prevention and Control Research Network (CPCRN) has been a leader in cancer-related dissemination & implementation (D&I) science. Given increased demand for D&I research, the CPCRN Scholars Program launched in 2021 to expand the number of practitioners, researchers, and trainees proficient in cancer D&I science methods. Methods:

The evaluation was informed by a logic model and data collected through electronic surveys. Through an application process (baseline survey), we assessed scholars’ competencies in D&I science domains/subdomains, collected demographic data, and asked scholars to share proposed project ideas. We distributed an exit survey …

Oyster Grower Perspectives On Green Crab (Carcinus Maenas) Interactions: Using Applied Social Science To Inform Research And Engagement, Kelsey Meyer-Rust, Lindsey Williams, Krystin Ward, Bonnie Brown

Faculty Publications

Research that informs the New Hampshire Aquaculture industry, which has grown significantly over the past few years, and helps the overall associated watershed community to keep Great Bay Estuary healthy is vital. Specific study of green crabs, Carcinus maenas, and their potential effects on oysters, Crassostrea virginica, is important to gain a better understanding of the impact invasive species may have on these ecologically and economically important bivalves. The aim of this study was to document and understand New Hampshire (NH) oyster growers’ perspectives on the issue of green crab predation of oysters. Through a survey, this study documented a …

Joint Subarray Acoustic Tweezers Enable Controllable Cell Translation, Rotation, And Deformation, Liang Shen, Zhenhua Tian, Kaichun Yang, Joseph Rich, Jianping Xia, Neil Upreti, Jinxin Zhang, Chuyi Chen, Nanjing Hao, Zhichao Pei, Tony Jun Huang

Faculty Publications

Contactless microscale tweezers are highly effective tools for manipulating, patterning, and assembling bioparticles. However, current tweezers are limited in their ability to comprehensively manipulate bioparticles, providing only partial control over the six fundamental motions (three translational and three rotational motions). This study presents a joint subarray acoustic tweezers platform that leverages acoustic radiation force and viscous torque to control the six fundamental motions of single bioparticles. This breakthrough is significant as our manipulation mechanism allows for controlling the three translational and three rotational motions of single cells, as well as enabling complex manipulation that combines controlled translational and rotational motions. …

Coastal Wetlands In The Anthropocene, John Day, Edward Anthony, Robert Costanza, Douglas Edmonds, Joel Gunn, Charles Hopkinson, Michael E. Mann, James Morris, Michael Osland, Tracy Quirk, Andre Rovai, John Rybczyk, Thomas Spencer, Jessica Stephens, Jaia Syvitski, Robert Twilley, Jenneke Visser, John R. White

Faculty Publications

We review the functioning and sustainability of coastal marshes and mangroves. Urbanized humans have a 7,000-year-old enduring relationship to coastal wetlands. Wetlands include marshes, salt flats, and saline and freshwater forests. Coastal wetlands occur in all climate zones but are most abundant in deltas. Mangroves are tropical, whereas marshes occur from tropical to boreal areas. Quantification of coastal wetland areas has advanced in recent years but is still insufficiently accurate. Climate change and sea-level rise are predicted to lead to significant wetland losses and other impacts on coastal wetlands and the humans associated with them. Landward migration and coastal retreat …

Hydrodynamic Exposure – On The Quest To Deriving Quantitative Metrics For Mariculture Sites, Oliver Lojek, Nils Goseberg, Heidi Moe Føre, Tobias Dewhurst, Thea Bölker, Kevin Gerald Heasman, Bela H. Buck, David W. Fredriksson, Samuel Rickerich

Faculty Publications

This work attempts to define metrics for hydrodynamic exposure, using known oceanographic variables to provide a universal site assessment method for mariculture structures. Understanding environmental conditions driving open-ocean mariculture siting is crucial in establishing consistent ocean governance, minimizing adverse environmental impacts, and facilitating economically sustainable farm operations. To provide a metric of oceanic conditions and associated requirements for structural design and operation of aquaculture systems, six Exposure Indices (EI) are proposed that consider physical energy levels related to hydrodynamic forces at a site. Four of the proposed indices consider only environmental conditions, while the other two also consider the dimensions …

Personalized Learning Path Problem Variations: Computational Complexity And Ai Approaches, Sean A. Mochocki, Mark Reith, Brett J. Borghetti, Gilbert L. Peterson, John Jasper, Laurence D. Merkle

Faculty Publications

E-learning courses often suffer from high dropout rates and low student satisfaction. One way to address this issue is to use personalized learning paths (PLPs), which are sequences of learning materials that meet the individual needs of students. However, creating PLPs is difficult and often involves combining knowledge graphs (KGs), student profiles, and learning materials. Researchers typically assume that the problem of creating PLPs belong to the nondeterministic polynomial (NP)-hard class of computational problems. However, previous research in this field has neither defined the different variations of the PLP problem nor formally established their computational complexity. Without clear definitions of …

Influence Of Redox Engineering On The Trade-Off Relationship Between Thermopower And Electrical Conductivity In Lanthanum Titanium Based Transition Metal Oxides, Mohammad El Loubani, Gene Yang, Seyed Morteza Taghavi Kouzehkanan, Tae-Sik Oh, Santosh Kiran Balijepalli, Dongkyu Lee

Faculty Publications

Discovery of new materials plays a critical role in developing advanced high-temperature thermoelectric (TE) applications. Transition metal oxides (TMOs) are one of the attractive candidates for high-temperature TE applications due to their thermal and chemical stability. However, the trade-off relationship between thermopower (S) and electrical conductivity (σ) limits the maximum attainable power factor (PF), thereby hindering improvements in TE conversion efficiency. To overcome this trade-off relationship, the emerging approach of the redox-driven metal exsolution in TMOs shows promise in improving both S and σ. However, the effect of metal exsolution with different particle sizes and …

Chatgpt Might Slow You Down: Verification Moderates Ai Uses And Learning Efficiency Among College Students, Ruonan Zhang, Nicky Chang Bi, Kate Salerno, Pelqin Chen

Faculty Publications

Generative artificial intelligence without a doubt is one of the most discussed topics in high-er education. It is still unclear whether ChatGPT is contributing to or hindering students’ learning efficiency. Built on the Technology Acceptance Model (TAM), this study is designed to examine the influence of ChatGPT usage of college stu-dents on their learning efficiency; to investigate the moderating effects of verification on the relationship between ChatGPT usage and learn-ing efficiency; and to investigate the relationship among ChatGPT usage and its antecedents, in-cluding subjective norm, job relevance, perceived usefulness, perceived ease of use, and intention to use. Using survey data …

Data-Driven Sparse Sensor Placement Optimization On Wings For Flight-By-Feel: Bioinspired Approach And Application, Alex C. Hollenbeck, Atticus J. Beachy, Ramana V. Grandhi, Alexander M. Pankonien

Faculty Publications

Flight-by-feel (FBF) is an approach to flight control that uses dispersed sensors on the wings of aircraft to detect flight state. While biological FBF systems, such as the wings of insects, often contain hundreds of strain and flow sensors, artificial systems are highly constrained by size, weight, and power (SWaP) considerations, especially for small aircraft. An optimization approach is needed to determine how many sensors are required and where they should be placed on the wing. Airflow fields can be highly nonlinear, and many local minima exist for sensor placement, meaning conventional optimization techniques are unreliable for this application. The …

Rootzone Soil Moisture Dynamics Using Terrestrial Water-Energy Coupling, Vinit Sehgal, Binayak P. Mohanty, Rolf H. Reichle

Faculty Publications

A lack of high-density rootzone soil moisture (θRZ) observations limits the estimation of continental-scale, space-time contiguous θRZ dynamics. We derive a proxy of daily θRZ dynamics — active rootzone degree of saturation (SRZ) — by recursive low-pass (LP) filtering of surface soil moisture (θS) within a terrestrial water-energy coupling (WEC) framework. We estimate the LP filter parameters and WEC thresholds for the piecewise-linear coupling between SRZ and evaporative fraction (EF) at remote sensing and field scale over the Contiguous U.S. We use θS from the Soil Moisture Active-Passive (SMAP) satellite and 218 in-situ stations, with EF from the Moderate Resolution …

Numerically Efficient Coherent Mode Representations For Partially Coherent Beams With Separable Phases, Milo W. Hyde, Carolina Rickenstorff

Faculty Publications

We present a method to numerically compute the coherent mode representations (CMRs) for partially coherent beams with separable phases. This special class of random light field has the ability to self-focus and is resistant to turbulence-induced degradation, making it potentially useful in applications such as optical communications. We validate our method by generating (in simulation) two such sources from the literature using their computed CMRs. Lastly, we conclude with a summary of our approach and a discussion of potential applications.

Development And Evaluation Of A Colorimetric Lamp Based-Assay Targeting The Bacteroides Hf183 Marker For Tracking Sewage Pollution In Environmental Waters, Mariah C.A. Do Nascimento, Wendy J.M. Smith, Metasebia Gebrewold, Yawen Liu, Stuart L. Simpson, Aaron Bivins, Paula Rahal, Warish Ahmed

Faculty Publications

Surface waters are vulnerable to contamination by human and animal feces, posing risks to human health due to potential exposure to enteric pathogens. This research developed a colorimetric loop-mediated isothermal amplification (cLAMP) assay to detect sewage associated Bacteroides dorei HF183/BacR287 (HF183) marker in wastewater and environmental water samples. The host sensitivity and host specificity of the assay were evaluated, and their performance was compared to the Bacteroides HF183 qPCR assay using control materials (gBlocks), environmental water samples seeded with untreated sewage, and ambient environmental water samples. In serial dilutions of control materials, qPCR produced quantifiable data across all dilutions, while …

Social Isolation And Loneliness Prevention Among Rural Older Adults Aging-In-Place: A Needs Assessment, Jodi L. Southerland, Shimin Zheng, Kayla Dodson, Erin Mauck, Juanita-Dawne R. Bacsu, Monique J. Brown Ph.D., Mph, Jeremy Holloway, Steffi M. Kim, Ayse Malatyali, Matthew Lee Smith

Faculty Publications

Introduction: The adverse effects of social isolation and loneliness (SI/L) have been documented among older adults in rural communities and contribute to poor health outcomes, premature disability and mortality, and increased burden on the healthcare system. The identification of factors contributing to SI/L among older adults can build the foundation for rural policymakers and leaders to allocate resources and develop tailored strategies more efficiently. The purpose of this article is to describe findings from a needs assessment designed to understand local factors that contribute to SI/L among rural older adults in a county in Northeast Tennessee. Findings from the needs …

Distributed Software Build Assurance For Software Supply Chain Integrity, Ken Lew, Arijet Sarker, Simeon Wuthier, Jinoh Kim

Faculty Publications

Computing and networking are increasingly implemented in software. We design and build a software build assurance scheme detecting if there have been injections or modifications in the various steps in the software supply chain, including the source code, compiling, and distribution. Building on the reproducible build and software bill of materials (SBOM), our work is distinguished from previous research in assuring multiple software artifacts across the software supply chain. Reproducible build, in particular, enables our scheme, as our scheme requires the software materials/artifacts to be consistent across machines with the same operating system/specifications. Furthermore, we use blockchain to deliver the …

Adding The Third Dimension: 3d Convolutional Neural Network Diagnosis Of Temporal Lobe Epilepsy, Erik Kaestner, Reihaneh Hassanzadeh, Ezequiel Gleichgerrcht, Kyle Hasenstab, Rebecca W. Roth, Allen Chang, Theodor Rüber, Kathryn A. Davis, Patricia Dugan, Ruben Kuzniecky, Julius Fridriksson Ph.D., Alexandra Parashos, Anto I. Bagić, Daniel L. Drane, Simon S. Keller, Vince D. Calhoun, Anees Abrol, Leonardo Bonilha, Carrie R. Mcdonald

Faculty Publications

Convolutional neural networks (CNN) show great promise for translating decades of research on structural abnormalities in temporal lobe epilepsy into clinical practice. Three-dimensional CNNs typically outperform two-dimensional CNNs in medical imaging. Here we explore for the first time whether a three-dimensional CNN outperforms a two-dimensional CNN for identifying temporal lobe epilepsy-specific features on MRI. Using 1178 T1-weighted images (589 temporal lobe epilepsy, 589 healthy controls) from 12 surgical centres, we trained 3D and 2D CNNs for temporal lobe epilepsy versus healthy control classification, using feature visualization to identify important regions. The 3D CNN was compared to the 2D model and …

Closed-Loop Adaptive Optics In The Presence Of Speckle And Weak Scintillation, Derek J. Burrell, Mark F. Spencer, Ronald G. Driggers

Faculty Publications

In this paper, we show that speckle averaging helps to improve adaptive-optics (AO) performance in closed loop as a result of reduced measurement error associated with a Shack–Hartmann wavefront sensor (SHWFS); however, this reduction is rendered ineffective with increasing beacon anisoplanatism. We do so operating in a weak-scintillation regime, where the SHWFS offers robust performance, and using in-plane translation of the illuminated rough surface to accomplish frame-to-frame speckle diversity. Understanding these trade-space limitations is critical when performing AO with non-cooperative, extended-source beacons.