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Fast-sparse-spanner: A practical algorithm for constructing low-stretch sparse geometric graphs
No full textWhen constructing geometric graphs (vertices are points and edges are line segments connecting point pairs) on pointsets, stretch-factor (worst-case detour between any point pair) is often considered a quality metric. A low stretch-factor (a quantity that is usually \u3e 1) guarantees short paths between all vertex pairs. A geometric graph having a stretch-factor of t is known as a t-spanner. Creating low stretch-factor geometric graphs for large pointsets with a low number of edges is an open problem in computational geometry.
In this work, we have designed and engineered a new simple and practical (fast and memory-efficient) algorithm named Fast-Sparse-Spanner algorithm for constructing sparse low stretch-factor geometric graphs on large pointsets in the plane. To the best of current knowledge, this is the first practical algorithm capable of constructing fast low stretch-factor graphs on large pointsets with averagedegrees (hence, the number of edges) competitive with that of greedy-spanners, the sparsest known class of Euclidean geometric spanners.
To evaluate the implementation in terms of computation speed, memory usage, and quality of output, extensive experiments were performed with synthetic and real-world pointsets, comparing results to Bucketing, the fastest known greedy spanner algorithm for pointsets in the plane, devised by Alewijnse et al. (Algorithmica, 2017). An experiment constructing a 1.1-spanner on a large synthetic pointset with 128K points uniformly distributed within a square demonstrated more than a 41-fold speedup, using roughly a third of the memory of Bucketing, with only a 3% increase in the average-degree of the resulting graph. When run on a pointset with a million points from the same distribution, a 130-fold speedup was observed, with roughly a fourth of the memory usage, and just a 6% increase in average-degree. In terms of diameter, the graphs generated by FastSparse-Spanner outperform greedy-spanners in most cases, exhibiting substantially lower diameter while maintaining near-greedy average-degree. Furthermore, the algorithm can be easily parallelized to take advantage of parallel environments.
As a byproduct of this research, Fast-Stretch-Factor was designed and engineered as a practical parallelizable algorithm to measure the stretch-factor of any graph generated by Fast-Sparse-Spanner. Experiments demonstrated that it is significantly faster than the naive Dijkstra-based stretch-factor measurement algorithm.
For broader uses and reproducibility of the results obtained, we have shared our code at https://github.com/ghoshanirban/FS
Spatial and temporal patterns in short-term surface sediment deposition and accretion at the Guana Tolomato Matanzas National Estuarine Research Reserve: Implications for resilience of coastal wetlands to sea-level rise
No full textCoastal wetlands are at risk of drowning due to the increasing threat of rising sea levels. Wetlands will have to build in elevation vertically or migrate horizontally to survive. Previous research has demonstrated that some wetlands have the potential to naturally build in elevation over time if deposition and accretion rates from allochthonous sediment delivery are substantial, but work in this area has been limited, and many coastal wetlands remain understudied. Portions of Northeast Florida are especially lacking in short-term surface deposition and accretion data. Without surface rates it is difficult to determine the vulnerability of different wetlands to rising sea levels. This project aims at measuring short-term surface deposition and accretion rates and identifying factors that drive rates in Northeast Florida. For this study, several short-term surface sediment deposition and accretion methods were tested during a 28-day deployment within the Guana Tolomato Matanzas National Estuarine Research Reserve (GTMNERR) to determine which methods were most effective at measuring rates. Ceramic tiles, borosilicate filters and centrifuge tube traps were deployed in varying wetland communities within the Reserve. Some methods were stapled and nailed to test ways to prevent dislodgment during deployments. The methods that were effective were then used during a yearlong study to measure short-term surface deposition and accretion rates seasonally in different wetland communities at the GTMNERR. It was found that the centrifuge tube trap and stapled ceramic tiles were the most efficient methods to measure short-term surface deposition and accretion rates. The main factors driving rates were platform edge distance, elevation, site and season. The results of this project will help to fill the data gap on short-term surface rates in the GTMNERR, Northeast Florida and beyond, which will inform management decisions to improve the resilience of coastal wetlands with rising sea levels
2024-2025 Annual Report
No full textAnnual report for the FY 2024-25 that includes impact highlights for student & faculty engagement, digital innovation, special collections, instruction & research, student awards, and more
President Limayem, Grand Opening Ceremony of the Allen Lastinger Center for Florida History - 2
No full textDr. Moez Limayem, President, University of North Florida, speaks at the Grand Opening Ceremony of the Allen Lastinger Center for Florida History, Thomas G. Carpenter Library. Date: September 5, 2025https://digitalcommons.unf.edu/alcfh-events/1010/thumbnail.jp
President Limayem, Grand Opening Ceremony of the Allen Lastinger Center for Florida History
No full textDr. Moez Limayem, President, University of North Florida, speaks at the Grand Opening Ceremony of the Allen Lastinger Center for Florida History, Thomas G. Carpenter Library. Date: September 5, 2025https://digitalcommons.unf.edu/alcfh-events/1009/thumbnail.jp
Analysis of bin packing variants
No full textThe Bin Packing problem is a classic and widely studied optimization problem that arises naturally in applications like manufacturing, logistics, and memory allocation, where space and resource constraints are critical. In this thesis, we first demonstrate the NP-completeness of Bin Packing via a reduction from Three-Dimensional Matching, establishing its foundational complexity. We then survey core heuristics for the one-dimensional case and extend our analysis to two and three-dimensional variants, including both offline and online strategies. Special attention is given to stochastic bin packing, where item sizes are modeled as random variables drawn from distributions such as uniform, truncated normal, and multinomial. Our experimental results show that classical heuristics can vary significantly in efficiency depending on the underlying distribution, revealing both limitations and potential adjustments needed for real-world, uncertain environments
Diversity makes me uncomfortable: Effects of diversity language on university student belonging
No full textDiversity statements and experiences form the first impressions students have of their prospective universities and employers, setting the stage for perceived feelings of belonging, otherness, and comfort within new environments (Baleria, 2021; O’Keeffe, 2013; Starck et al., 2021). Diversity statements can signal feelings of comfort and belonging or feelings of stress depending on the way in which diversity is framed (Chaney, 2022; Trawalter et al., 2016). This is especially true for students, who are more often affected mentally and physically by changes in university diversity perspectives (Sladek et al., 2021) The current study thus uses a novel blood pressure measure to examine potential biomarkers for diversity language discomfort in a 2 (Diversity is Good/Diversity is Fair) x2 (Diversity is Moral/Diversity is Instrumental) study design. Student participants’ (n=48) blood pressure was measured via a BioPac NIBP100-EHD finger and arm cuff as they read a proposed university diversity statement. Contrary to expectations, students did not show significant changes in comfort, belonging, diversity motivation, affirmative action knowledge/confidence, or agreement between Good/Fair and Moral/Instrumental conditions. Student agreement with diversity was linked to student comfort with diversity, however. Above-baseline scale scores also suggest that students felt generally positive feelings of comfort, belonging, diversity-oriented motivation, affirmative action knowledge/confidence, and agreement after reading a diversity statement. Future studies will account for students’ political viewpoints as well as seek larger, more diverse samples to better determine how different diversity statements can benefit long-term student belonging outcomes
Tensions Between Education Policies and Standards and Educators’ Multilingual Practices: Two Case Studies from India and the United States
No full textThrough two case studies from India and the United States, we explore how educational policies and standards focused on multilingualism are interpreted and enacted within early childhood education classrooms. Recent education policies in both contexts are aimed at fostering culturally responsive and linguistically inclusive pedagogy for greater academic success for students whose home language(s) differs from the language of instruction. However, the policy implementation varies significantly based on educators’ language ideologies and cultural beliefs. We examine a critical gap between policy intentions and classroom realities. Our findings suggest that while broad educational policies provide important frameworks, their effectiveness relies upon educators’ interpretation and beliefs, highlighting a need for clearer guidelines to better implement policy to enhance emergent multilingual learners’ language acquisition
Glassboro Estate Postcard
No full textCorrespondence: M. C. Kendrick, General Representative, Glassboro Estate, Norfolk, Virginia postcard. Undated. Part of Miscellaneous postcards