50107 research outputs found
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Community-Based Tourism in Hogsback, Eastern Cape: A Pathway to Sustainable Development
No full textThis paper will explore the potential of Community-Based Tourism (CBT) as a driver for sustainable development within rural communities, using Hogsback in the Eastern Cape of South Africa as a case study. The paper will focus on community participation, sustainable tourism management, and local empowerment, aiming to uncover how CBT can foster economic resilience, cultural preservation, and environmental stewardship. The methodology will involve qualitative research techniques, including semi-structured interviews, focus groups, and participant observation to gather diverse perspectives from stakeholders. This research is anticipated to contribute valuable insights to the field of rural tourism and sustainable development, informing policymakers, practitioners and community stakeholders about the benefits and challenges of implementing CBT in similar contexts
Soil Moisture Estimates Using -Band Airborne SAR Over Forests Replicating NISAR Observations<italic/>
No full textAirborne SAR observations of soil moisture conditions at 6-m resolution are analyzed over deciduous and evergreen forests in the U.S. Northeast during the 10-day spring and 14-day summer periods in 2022. During the summer, the dynamic range of HH is about 1 dB, associated mostly with soil moisture changes. Larger changes in backscattering are found between the two seasons, reflecting the vegetation effect. In spring, backscattering decreases in time, suggesting the impact of drying trunks and thickening foliage. In summer, sigma degrees correlates highly with in situ soil moisture, consistently between ascending and descending viewing geometry on flat terrain and on slopes only when imaged at similar incidence angles. The consistency benefits NISAR's retrieval by allowing more frequent consistent retrievals of soil moisture. Soil moisture was retrieved using HH to replicate NISAR observations and its accuracy in the eight sites is 0.067 m(3)/m(3) in unbiased RMSE, assessed over a 140-m domain per in situ site. The results are very encouraging as an independent test of the retrieval algorithm under the challenging conditions of surface slope or forest vegetation. Deficiencies in the retrieval algorithm appear to originate from the modeling of vegetation effect and topography. As long as the two causes are temporally static, they introduce a bias error. However, the temporal range of the retrieval is the most useful property for applications and matches well with in situ observations
Parsing social context in auditory forebrain of male zebra finches
No full textTo understand the influence of natural behavioral context on neural activity requires studying awake-behaving animals. Microdrive devices facilitate bridging behavior and physiology to examine neural dynamics across behavioral contexts. Impediments to long-term single unit recordings in awake-behaving animals include tradeoffs between weight, functional flexibility, expense, and fabrication difficulty in microdrive devices. We describe a straightforward and low-cost method to fabricate versatile and lightweight microdrives that remain functional for months in awake-behaving zebra finches (Taeniopygia guttata). The vocal and gregarious nature of zebra finches provide an opportunity to investigate neural representations of social and behavioral context. Using microdrives, we report how auditory responses in an auditory association region of the pallium are modulated by two naturalistic contexts: self- vs. externally-generated song (behavioral context), and solitary vs. social listening (social context). While auditory neurons exhibited invariance across behavioral contexts, in a social context, response strength and stimulus selectivity were greater in a social condition. We also report stimulus-specific correlates of audition in local field potentials. Using a versatile, lightweight, and accessible microdrive design for small animals, we find that the auditory forebrain represents social but not behavioral context in awake-behaving animals
PDMS Brushes as Soft Materials in Elastomers and Photonic Crystals
No full textBottlebrush polymers exhibit ultra-softness and low viscosity compared to linear polymers due to minimal chain entanglement. These unique properties make them highly suitable for applications such as elastomers and photonic crystals, where their fast assembly and large domain spacing are advantageous. This dissertation focuses on three key developments: 1) PDMS brush polymers with hydrogen bonding for self-healing, 2) the development of polyrotaxane crosslinked bottlebrush polymers 3) the study of stretchable photonic crystals based on PDMS block bottlebrush copolymers are discussed.
First, the self-healing properties were achieved in PDMS brush polymers by crosslinking via hydrogen bonding. Three different strengths of hydrogen bonding were evaluated, and their temperature response was compared as hydrogen bond association is a function of temperature. Additionally, PDMS brush polymers were crosslinked using polyrotaxane, a slide-ring crosslinker known to improve elongation and toughness. This novel combination of polyrotaxane and bottlebrush polymers was successfully synthesized.
Finally, leveraging the softness and rapid assembly behavior of block bottlebrush copolymers, stretchable photonic crystals were developed. These photonic crystals were fabricated using two sets of PDMS-based block bottlebrush copolymers with different molecular weights and additives, forming spherical structures that exhibited red and blue colors, respectively. The reflection spectra of these crystals responded to applied strain, demonstrating color shifts (or no color shifts) that were influenced by the degree of crosslinking and polymer structure, highlighting the potential for switchable optical properties in flexible photonic materials.Doctor of Philosophy (Ph.D.)2026-02-0
Study of Charged Macromolecule Phase Behavior using Conventional and Modern Modeling Methods
No full textCharged macromolecule systems serve as a wonderful basis for the study of the fundamental physics underlying biological phenomena. They provide relatively clean, simple systems, displaying rich physics due to their many degrees of freedom, short-ranged van der Waals interactions, long-ranged Coulomb interactions, entropic contributions arising from the mobile species, and chain connectivity. The self-assembly of charged macromolecules likely played a vital role in the emergence of life through equilibrium phase behavior like liquid-liquid phase separation and complex coacervation. In this work, we study the equilibrium phase behavior of charged macromolecule systems using conventional modeling techniques, like free energy minimization using numerical methods, and modern methods, like machine learning models, when computational barriers restrict more systematic analysis. We study the pH-responsive complex coacervation between polyzwitterions and polyelectrolytes — an interesting class of complex coacervates that are found to be stable at pH values considerably different from complex coacervates formed between polyelectrolytes. Developing new theory, we probe the many physicochemical parameters to explore the characteristics of their phase behavior. We then study the microphase separation transition behavior of sequence-defined polymers, those in which can only be distinguished by their unique monomer sequence and are analogous to proteins. The influence of monomer ordering plays a well known role in the assembly and conformations of charge macromolecules. Those sequence- dependent effects are only beginning to become unraveled and a systematic molecular dynamics study faces computational barriers. A machine learning-aided study of sequence-dependent effects on charged sequence-defined polymer phase behavior is conducted. First, we train a gradient boosted decision tree model to predict the microphase separation transition from the monomer sequence. From there, we study the learned patterns from the model to provide qualitative relationships between monomer order and microphase behavior.PPG Fellowship, NSF DMR-2309539, NSF CHE-1904660, AFOSR Grant FA9550-23-1-0584. NIH 2R01HG002776-14A1Doctor of Philosophy (Ph.D.)2026-02-0
Experimental Mechanics of a Highly Articulated Backbone for Soft Snake Robots
No full textBackbones are a critical component of bioinspired snake robots, providing structural support and actuator attachment points. Current soft snake robots overwhelmingly rely on
continuum backbones, which are continuous strips or rods. Continuum backbones are straightforward to manufacture and integrate, but also tie torsional stiffness, bending
stiffness, buckling load and maximum curvature, e.g., increasing cross-section size to raise buckling load must increase bending stiffness in at least one direction. Biological snakes, in contrast, have highly articulated backbones that break these scalings but also have complex vertebra geometry and musculature to manage the articulation.
In this work, we develop and test a concept for a highly articulated, snake-inspired backbone and a corresponding actuator layout with two actuator types. The artificial
vertebrae and actuator layout include versions of key features identified in biology literature, such as articulation points and motion limiters. We experimentally identify
bending range of motion in two planes, note emergent twist, and demonstrate locomotion.
While only a first step, this work demonstrates a potential alternative approach to soft snake robot design, and suggests that increasing mechanical complexity of soft robots
may be more tolerable than previously assumed. Emergent behaviors suggest a path forward for producing complex movements from simple actuation inputs, but further work is needed to model robot mechanics.Master of Science (M.S.)2025-11-1
Counterfeits: Stories
No full textThe following short story collection, Counterfeits, includes nine stories and serves as the culmination of my work as an M.F.A. candidate at the University of Massachusetts, Amherst. This collection is intended to explore in close detail the lives of modern women and girls. The stories contained within are not explicitly interconnected, but are loosely thematically cohesive. As a writer of fiction, I am particularly interested in relationships between and among women, and in the ways systems of oppression are often upheld and enforced by the very people they victimize. Beyond this, I also intend for the collection to explore the ways in which systemic forces, more specifically capitalism, class conflict, sexual and relational dynamics, and gender roles, play out in the most private spaces of womens’ lives. These themes are, intentionally, rather general -- I hope mostly to emulate some of my favorite story collections, which simply compile a number of very good stories in a single book. To this end, I focused my revision process on polishing and strengthening each individual piece. I hope that this hard work and effort is visible in the draft that follows. I would like to extend my thanks to the members of my committee for your tutelage and guidance over the past three years, and your close reading of this book.Graduate Teaching Associateship, Writing Program, UMass AmherstMaster of Fine Arts (M.F.A.)2030-05-1
Earthquake Weather
No full textThis is a collection of short stories.Master of Fine Arts (M.F.A.)2030-05-1
Care Full: A Novel
No full textCare Full is a novel set in a dystopian world similar to ours where there are Siphoners, workers similar to therapists who take on physical “bloat” in addition to the emotional, and where care is lashed to capitalism and there are few swimmable bodies of water due to the effects of climate change. The novel is told through the perspective of a Siphoner called Nettie, who among other things, is looking for complete annihilation of ego through their work caring for others, and tries to avoid “bloatout”, this world’s version of burnout. At the cult-like clinic Nettie works for, they are told they can avoid bloat out through “becoming water”, and they enroll in a mysterious study to learn how to do so, all the while taking care of mentally ill teenagers and bonding with their colleagues in a hot tub warehouse called the Tub ‘N Tan. While Nettie learns to excel at becoming water, they soon learn with the help of their Internet friend from childhood, their participation in the study and resultant practice may be making them easier to exploit. Worse yet, it may be causing harm to others.Master of Fine Arts (M.F.A.)2030-05-1
DEVELOPING AN OPTIMAL 360-DEGREE VIDEO STREAMING SYSTEM USING MULTICASTING FOR IMPROVED QUALITY OF EXPERIENCE
No full textThe growing popularity of 360-degree video content has ushered in new opportunities for immersive multimedia experiences, enabling users to explore visual content from any perspective. However, the substantial bandwidth requirements for transmitting such content, especially over mobile networks, pose significant challenges. Current streaming techniques often fail to efficiently manage the increased data load, particularly when multiple users are
engaged simultaneously.
In this thesis, we propose a novel multicast-based approach to optimize the transmission of 360-degree video. By leveraging tiling techniques, our system divides video into segments corresponding to a user’s Field of View (FoV). Only the relevant FoV tiles are streamed at the highest quality, while other areas are transmitted at lower resolutions, reducing unnecessary band width consumption. Additionally, our multicast strategy groups users with similar viewing patterns to share common video tiles, further improving bandwidth efficiency without compromising the Quality of Experience (QoE).
The proposed system is designed to adapt dynamically to user behavior and network conditions, utilizing a linear optimization model to intelligently select and multicast tiles. We evaluate our approach using real-world user data and various network conditions. Experimental results demonstrate significant reductions in bandwidth usage while maintaining superior video quality, as measured by Video Multi-Method Assessment Fusion (VMAF) scores.
This thesis offers a scalable solution for bandwidth-efficient 360-degree video streaming, opening the door to more accessible immersive media experiences, especially in bandwidth-constrained environments. Future work includes exploring hybrid approaches and expanding the system’s implementation to wireless networks.Master of Science (M.S.)2025-11-1