Showing 491 - 500 of 681 Items
Exploring the Effect of Core Tactics and Demographics on Squash
Gameplay Patterns Using Computer Vision
Date: 2025-01-01
Creator: Abhiroop Reddy Nagireddygari
Access: Open access
- This paper presents a computer vision system for analyzing common tactical and training pat- terns in squash using player locations and movement dynamics. Leveraging convolutional neural networks (CNNs) such as YOLO and TrackNet, we extract player coordinates on a squash court through a lightweight, single-camera framework. Match footage and detections are segmented by gender, skill level, and match phase to enable contextual comparisons. From 2D coordinates, we generate heatmaps of player locations, court coverage percentages, and distance-over-time graphs to visualize movement tendencies. Our results show that women demonstrate greater ball control and accuracy than men across all levels, while professional players exhibit more aggressive court usage than amateurs. We also identify that games 2 and 3 are the most physically demanding, highlighting a balance between slow starts and fatigue.
Demagogues of Disunion: The Role of Honor in Southern Secession Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Evan Robert Cote Chapman
Access: Access restricted to the Bowdoin Community
Energy Policy is a Highway: Federal Energy Policy Evolution in the United States Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2025-01-01
Creator: Chelsea Moody
Access: Access restricted to the Bowdoin Community
La representación literaria y la construcción espacial de la pampa argentina – un
análisis de textos desde el siglo XIX hasta el XXI
Date: 2025-01-01
Creator: Kaitlyn Brunner
Access: Open access
- This paper analyzes the spacialization of the pampa in Argentine literature, both canonical works and contemporary ones. How is rurality and the Argentine countryside represented in these works? How do they expand upon or challenge each other? The immensity of the pampa and its vast plains has served as a focal point of fascination for various authors and Argentine political leaders, intimately related to ideas of frontier and progress. It has served as a site for various political dreams and agendas throughout history and presidential administrations, even to propel its own extermination project to assert dominion over the pampa and assassinate its own Indigenous people. The various conceptualizations of the pampa and the people who inhabit and care for the land—the gauchos and indigenous communities—demonstrate a larger dichotomy of the city and the urban versus the countryside and the rural, or as Sarmiento puts it—civilization and barbarie. The effort to tame the ‘wild’ pampa produces the immense projects of agricultural development that we see today, degrading the land and poisoning the bodies of rural people. More contemporarily, the spacialization of the city and the country in contemporary Argentine literature begins to subvert and defy the traditional binary thinking of the two spaces. I analyze Argentine literature from the 19th century to the 21st century to show how the locus of the pampa and other rural spaces has changed over time, showing the reconfiguration of the country’s landscape in literature.
GEM-PSO: Particle Swarm Optimization Guided by Enhanced Memory
Date: 2019-05-01
Creator: Kevin Fakai Chen
Access: Open access
- Particle Swarm Optimization (PSO) is a widely-used nature-inspired optimization technique in which a swarm of virtual particles work together with limited communication to find a global minimum or optimum. PSO has has been successfully applied to a wide variety of practical problems, such as optimization in engineering fields, hybridization with other nature-inspired algorithms, or even general optimization problems. However, PSO suffers from a phenomenon known as premature convergence, in which the algorithm's particles all converge on a local optimum instead of the global optimum, and cannot improve their solution any further. We seek to improve upon the standard Particle Swarm PSO algorithm by fixing this premature convergence behavior. We do so by storing and exploiting increased information in the form of past bests, which we deem enhanced memory. We introduce three types of modifications to each new algorithm (which we call a GEM-PSO: Particle Swarm Optimization, Guided by Enhanced Memory, because our modifications all deal with enhancing the memory of each particle). These are procedures for saving a found best, for removing a best from memory when a new one is to be added, and for selecting one (or more) bests to be used from those saved in memory. By using different combinations of these modifications, we can create many different variants of GEM-PSO that have a wide variety of behaviors and qualities. We analyze the performance of GEM-PSO, discuss the impact of PSO's parameters on the algorithms' performances, isolate different modifications in order to closely study their impact on the performance of any given GEM-PSO variant, and finally look at how multiple modifications perform. Finally, we draw conclusions about the efficacy and potential of GEM-PSO variants, and provide ideas for further exploration in this area of study. Many GEM-PSO variants are able to consistently outperform standard PSO on specific functions, and GEM-PSO variants can be shown to be promising, with both general and specific use cases.
The effects of nitric oxide on the modulation of the cardiac system of the American lobster, Homarus americanus, via a peptide (GYSDRNLRFamide)
Date: 2014-08-01
Creator: Sophie Janes
Access: Open access
- The central pattern generator (CPG) is a neural network that controls the rhythmic patterned outputs, which generate locomotion as needed. The lobster provides a good model to study CPGs because it has a relatively simple CPG. The lobster CPG, or cardiac ganglion accommodates for a range of activities and changes in the environment (Cooke, 2002).The small lobster CG is made up of nine neurons that control the neurogenic heart. The lobster CG is located on the inner dorsal wall of the heart and forms long neurites that branch onto the heart muscle. The CG, through an intrinsic mechanism, generates patterned and rhythmic bursts to the heart (Cooke 2002).The H. americanus CG sends information to the heart muscle to regulate the heart beat. The patterned bursts from the CG need to be adjusted in response to changing demands, for example, activity level or blood volume. Two general mechanisms, intrinsic feedback and extrinsic neuromodulation, have been identified to facilitate this adjustment. Through an intrinsic feedback mechanism, the muscle sends information back to the CG via a positive pathway and a negative pathway. In the positive pathway, stretch-sensitive dendrites of cardiac neurons increase the frequency of heart contractions when stretched (Cooke 2002). In the negative pathway, nitric oxide (NO), produced by the cardiac muscle, slows the frequency (Mahadevan et al. 2004). The interplay between the negative and positive feedback pathways regulates the output of the CG. An extrinsic mechanism has also been identified to regulate the CG output. Chemical neuromodulators that are released either locally or as hormones signal to the heart or CG to modulate ganglion activity. The intrinsic and extrinsic mechanisms affect the contraction amplitude and frequency of the heart.Within this simple invertebrate organism, a complex layering of control exists. Studies of the effects of various extrinsic modulators suggest that these modulators may alter how the feedback pathways operate. I examined what effect the neuromodulator GYSDRNLRFamide (GYS), a peptide found in the lobster nervous system, has on the balance between the positive and negative pathways (Ma et al., 2008). Recent experiments have demonstrated that when GYS was applied at high concentrations in the whole heart, the frequency decreased. This suggests that GYS may play a role in the intrinsic feedback pathways, and likely enhances the negative pathway.I looked at if nitric oxide altered the modulation of the heartbeat frequency when enhanced by the extrinsic modulator, GYS. Based on previous experiments, I hypothesized that GYS allows the NO, or negative pathway to predominate. In order to test my hypothesis, I examined the effects of GYS when I removed nitric oxide, which allows the negative pathway to exist. I compared the characteristics of the heartbeat when saline was run through the heart to when GYS was run through the heart. I also compared the characteristics of the heartbeat when the NO inhibitor, L-NA, was applied to when GYS was applied in the presence of L-NA. I finally compared the changes in frequency between these two comparisons. I found a significant difference between the change in frequency of the heart perfused with GYS in saline as opposed to perfused with GYS in L-NA. GYS had a greater negative effect without L-NA. These results demonstrate that NO is likely the cause of the observed decrease in frequency. Final Report of research funded by the Doherty Coastal Studies Research Fellowship.
Lie to Me: Linguistic Markers of Deception in Relation to Individual Differences in Executive Control Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2014-05-01
Creator: Lauren Pashkowski
Access: Access restricted to the Bowdoin Community
"I Deny Your Authority to Try My Conscience:" Conscription and Conscientious Objectors In Britain During the Great War
Date: 2019-05-01
Creator: Albert William Wetter
Access: Open access
- During the Great War, the Military Service Act was introduced on January 27, 1916 and redefined British citizenship. Moreover, some men objected to the state’s military service mandate, adamant that compliance violated their conscience. This thesis investigates how the introduction of conscription reshaped British society, dismantled the “sacred principle” of volunteerism, and replaced it with conscription, resulting in political and popular debates, which altered the individual’s relationship with the state. British society transformed from a polity defined by the tenets of Liberalism and a free-will social contract to a society where citizenship was correlated to duty to the state. Building off Lois Bibbings’ research on conscientious objectors, this thesis nuances the analysis with the case studies of David Blelloch and Norman Gaudie. Framed by two theories—Benedict Anderson’s imagined community and Barbara Rosenwein’s emotional community—these case studies demonstrate how conscientious objectors exposed the incongruence of the British imagined and emotional community, and the redefinition of citizenship. By weaving these theories into the British Great War tapestry, this thesis contends that the British nation was imagined differently before the war than it was after the war because of the introduction of conscription. Drawing from parliamentary debate transcripts, newspaper articles, and archival material from the Imperial War Museum in London, and the Liddle Personal Collection at the University of Leeds, Blelloch’s and Gaudie’s respective case studies ultimately bait the question: “What does it mean to be British?”
Characterization of Dissolved Organic Matter in Local Marine and Terrestrial Waters
Date: 2014-08-01
Creator: Anna Bearman
Access: Open access
- There are numerous anthropogenic pollutants present in both marine and terrestrial waters.1 Though many of these chemicals do not absorb light and therefore cannot undergo photolyic degradation on their own, dissolved organic matter (DOM), found alongside pollutants in natural aquatic waters, can act as a catalyst in the attenuating process of contaminants. DOM is a complex mixture of organic compounds derived from decaying plants, animals and microorganisms. Since DOM can absorb light, it can transfer energy to contaminants, allowing them to break into smaller and often less hazardous molecules. The behavior of DOM is largely determined by its functional chemical components, and the character of DOM is constantly changing with the environment. For example, two International Humic Substances Society standards Pony Lake DOM from Antarctica and Suwannee River DOM from Georgia demonstrate very different compositions and characteristics2. More important than simply identifying varying functional groups in DOM these standards, however, may be understanding how our local water in the Androscoggin River and Gulf of Maine behaves and attenuates contaminants. The goal for this project was to first isolate DOM from the Androscoggin River and the Gulf of Maine. DOM was extracted using the Thurman and Malcolm procedure,3 beginning with collection and filtration of water from the Androscoggin River boat launch and Simpson’s Point. The water was then run through a chromatography column, through the method of absorption chromatography the dissolved organic matter sticks to the resin within the column. DOM was then eluted from the column, concentrated, and protonated with an ion exchange column. The resulting concentrated DOM solution was then freeze-dried to obtain the final powdered DOM fraction. Because the quantity of DOM isolated from the Gulf of Maine was too small for characterization, we determined that a new collection method using equipment suited for sampling larger volumes of water will be necessary for future DOM characterization. Instead we focused on collecting samples from the Androscoggin on a weekly basis. Following isolation, the Androscoggin River DOM was dissolved in Type I water to make 3mg/L DOM samples and then characterized through UV-Vis absorption and 3D fluorescence Excitation-Emission Matrix (EEM) spectroscopy techniques. The data was then processed using the parallel factor analysis (PARAFAC) method.4 PARAFAC deconvolutes the fluorescence spectra into the distinct fluorescent components present in the complex DOM mixture (Figure 1). This preliminary analysis indicates that Androscoggin River DOM is made up of at least six specific fluorophores. In the future, I will identify the types of molecules responsible for each component signature and attempt to ascertain the relative concentration of each photoactive constituent in the DOM samples. This information will have significant implications for the photochemistry of natural and anthropogenic chemicals in natural waters. Funded by the Henry L. Grace Doherty Coastal Studies Research Fellowship and James Stacy Coles Summer Research Fellowship in Chemistry.
Using metabolic oligosaccharide engineering to induce immune-mediated cell killing of bacterial pathogens Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Brendan H. Pulsifer
Access: Access restricted to the Bowdoin Community