Honors Projects
Showing 151 - 160 of 662 Items
DS-PSO: Particle Swarm Optimization with Dynamic and Static Topologies
Date: 2017-05-01
Creator: Dominick Sanchez
Access: Open access
- Particle Swarm Optimization (PSO) is often used for optimization problems due to its speed and relative simplicity. Unfortunately, like many optimization algorithms, PSO may potentially converge too early on local optima. Using multiple neighborhoods alleviates this problem to a certain extent, although premature convergence is still a concern. Using dynamic topologies, as opposed to static neighborhoods, can encourage exploration of the search space at the cost of exploitation. We propose a new version of PSO, Dynamic-Static PSO (DS-PSO) that assigns multiple neighborhoods to each particle. By using both dynamic and static topologies, DS-PSO encourages exploration, while also exploiting existing knowledge about the search space. While DS-PSO does not outperform other PSO variants on all benchmark functions we tested, its performance on several functions is substantially better than other variants.
Functional redundancy of a non-native foundation species (eelgrass, Zostera japonica) across intertidal stress gradients
Date: 2023-01-01
Creator: S. Maria Garcia
Access: Open access
- Non-native species foundation species can alter ecosystems in both positive and negative ways. The creation of habitat can be beneficial to native species when they provide a limiting resource or in a stressful environment. Yet this creation of habitat can also be detrimental by replacing native species and/or facilitating the presence of more non-native species. In Willapa Bay, WA, a non-native foundation species, Zostera japonica, co-exists with the native foundation species Zostera marina. Zostera japonica persists at the higher intertidal in monocultures, the two species overlap in the mid intertidal, and Z. marina persists in monocultures in the low intertidal. Epifaunal invertebrates, the organisms that live on eelgrass blades, connect eelgrass to higher trophic levels. Through a series of transplants and removals, I used this zonation pattern to ask if the two species can fulfill a similar functional role in respect to epifaunal invertebrates (functional redundancy), and if this was due to the identity of the foundation species or a response to the stress gradient of the intertidal. My results suggest that the epifaunal invertebrate community is responding more to the physiological stress gradient, and the functional redundancy of the two species depends on the location they are found. Z. japonica is expanding the range of vegetated habitat into to the physiologically stressful high zone, which supports a different community. This experiment highlights that the impacts of non- native species are highly localized and that abiotic and biotic factors are important to trophic interactions.
Postmemory’s Shadow Archives: Reshaping the Punctum in Asian Diaspora Poetry This record is embargoed.
Date: 2024-01-01
Creator: Hannah Kim
A Practical Study in Conducting Renaissance and Contemporary Choral Music During the COVID-19 Pandemic Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2021-01-01
Creator: Emily M. Ha
Access: Access restricted to the Bowdoin Community
A Fatal Mistake or a Paradigm Shift? Noguchi Hideyo and the Global Reimagining of Yellow Fever
Date: 2025-01-01
Creator: Seth Gorelik
Access: Open access
Mythologisation, magnification, et modification : La Culture de la langue française
Date: 2025-01-01
Creator: Rachel Houston Scruby
Access: Open access
- Across three chapters, this thesis examines how the French language plays a vital role not only as a vehicle for communication but as an incarnation of culture, and how France makes sense of linguistic and cultural changes today through the lens of its long history. An analysis of historical documents from key moments in this history illuminates French’s central role as an instrument of power reliant on a prioritization of elegance and beauty, an equivalency between language and people based in a grand history, and a global influence. It shows how this history constructed the language as a political tool, capable of bolstering France’s global importance through “soft power.” This created not only the conditions for the imposition of French to combat fears of decline in military and political domains, but also a simultaneous conflict between the language as an expression of elegance and as a tool to be spread widely to assert the country’s dominance, particularly during the colonial period. Close examination of this long and intricate history illuminates our understanding of how France currently works to reconcile its history with its present in a world where the French language is far more widely spoken than at any other period but is no longer the primary possession of France itself.
Fitness and sex effects of a novel microsporidian parasite on its Daphnia host
Date: 2025-01-01
Creator: Gracie Scheve
Access: Open access
- Parasitism can influence host ecology and evolution in powerful ways, although the specific impacts on host fitness and life history may be context dependent and involve complex trade-offs. In this study, I investigated the effects of a novel microsporidian gut parasite on Daphnia ambigua, a freshwater zooplankton with a cyclical parthenogenetic life cycle. Combining extensive field sampling at Sewall Pond, Maine, with chronic exposure experiments in the lab, I assessed the parasite's impact on Daphnia fitness and propensity to shift from asexual to sexual reproduction. Field observations revealed a correlation between gut parasite prevalence and increased production of males and sexual females, independent of known sex inducers such as crowding, food limitation, and photoperiod. Lab experiments confirmed that chronic spore exposure significantly reduced Daphnia survival and reproductive output, particularly in clones previously naïve to this strain of the parasite. However, no induction of sex or male offspring was observed in response to parasite exposure under laboratory conditions. This suggests that more complex environmental interactions might be triggering sex in Daphnia. While sex provides the benefit of increased genetic diversity for future generations, I hypothesize that while Daphnia undergo sexual reproduction their ability to resist or tolerate parasite infection is diminished. Phylogenetic analyses indicate the parasite is closely related to the less virulent microsporidian Ordospora pajunii but genetically distinct, potentially constituting a new species or genus. These findings provide insight into the ecological and evolutionary tradeoffs involved in host-parasite interactions and introduce a new host-parasite system for this study.
Chains for Change: Mathematical Modeling of Boston’s Eviction Court Cases Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Brian Liu
Access: Access restricted to the Bowdoin Community
Mesurer l’identité : pourquoi les jeunes français se détournent du vin ?Measuring Identity: What’s Turning the Young French Away from Wine?
Date: 2025-01-01
Creator: Siyi (Jonathan) Li
Access: Open access
- We use a randomized discrete‑choice experiment with 381 French adults to investigate why France’s wine consumption decline is most pronounced among the young. The treatment group subjects were primed via a video about France’s viticultural heritage, which raises the probability of choosing French red wine over French amber beer by 14 percentage points for Generation X but lowers it by 15 points for Generation Z. Using observational data collected after the experiment, 2SLS estimates show that the decline of wine in France is primarily due to a weakened sense of “French wine identity.” The study provides the first causal evidence for the role of identity in consumption choices and cautions that heritage‑based marketing may backfire with younger cohorts, suggesting instead modernity‑ and sustainability‑oriented strategies for the wine sector.
Building (Cellular) Barriers: Identifying cellularization dynamics involving somatic Xchromosome eliminations in Bradysia coprophila embryonic development This record is embargoed.
Date: 2025-01-01
Creator: Aale J. Agans
Access: Permanent restriction