Digital Commons Network^™

Improving Neural Network Efficiency With Multi-Fidelity And Dimensionality Reduction Techniques, Vignesh Sella, Thomas O'Leary-Roseberry, Xiaosong Du, Mengwu Guo, Joaquim R.R.A. Martins, Omar Ghattas, Karen Willcox, Anirban Chaudhuri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Design problems in aerospace engineering often require numerous evaluations of expensive to-evaluate high-fidelity models, resulting in prohibitive computational costs. One way to address the computational cost is through building surrogates, such as deep neural networks (DNNs). However, DNNs may only be an effective surrogate when sufficient evaluations of the high-fidelity model are required such that the up-front training cost is amortized, or in situations that require real-time responses (such as interactive visualizations). Typically, the data requirements for adequately accurate training of DNNs are often impractical for engineering applications. To alleviate this issue, the proposed work utilizes output dimensionality reduction along …

Tensile Behavior Of Directed Energy Deposited Bi-Metallic Ti-Ni-Based Alloy At Interfacial Area, Yitao Chen, Cesar Ortiz Rios, Frank Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Ti-Ni-based bi-metallic shape memory alloy was fabricated using directed energy deposition, and the tensile testing behavior at two sections after post-heat treatments were focused. The Ti-rich Ti-Ni-Cu ternary shape memory alloy was first fabricated on a TiNi shape memory alloy with near-equiatomic composition to achieve multi-functional shape memory behaviors using powder-based additive manufacturing. The bi-metallic part then underwent 400°C and 600°C heat treatment at the interfacial area, and the interfacial area was subject to tensile loading and unloading. The digital image correlation technique was applied to extract the tensile stress–strain behavior and map out the local strain evolution of …

Advancing Cislunar Space Domain Awareness Through Robust Optimization Framework For Optical Sensors-Based Autonomous Satellite Systems, Smriti Nandan Paul, Siwei Fan, Igor Panfil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The number of cislunar resident space objects is expected to proliferate rapidly because of strategic interests targeting long-term presence on the Moon and exploration of other planets (e.g., Artemis Accords) and liberalization of space through the entry of private space players (e.g., Intuitive Machines). It necessitates expanding current near-Earth space domain awareness (SDA) operation systems and knowledge to the relatively unexplored cislunar region. Besides the traditional complexities, xGEO orbits (orbits beyond the geosynchronous Earth orbit (GEO) region) face additional challenges because of highly non-linear and non-Keplerian dynamics, which results in inaccuracies in uncertainty propagation and state estimation. Further challenges include …

High-Order Dynamic Mode Decomposition For Multidimensional Harmonic Retrieval, Yanming Zhang, Steven Gao, Lijun Jiang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Estimating channel parameters such as azimuth, elevation, Doppler shift, and delay is a key challenge in wireless communication, often formulated as a multidimensional harmonic retrieval (MHR) problem. To address this, we propose a high-order dynamic mode decomposition (HODMD) framework for robust frequency estimation from high-dimensional signals in noisy environments. The HODMD approach combines high-order singular value decomposition (HOSVD) to decompose tensor data into a core tensor and mode matrices, with dynamic mode decomposition (DMD) to extract frequencies from the imaginary parts of the DMD eigenvalues. Simulation examples validate the effectiveness of the proposed method, demonstrating its efficiency in solving MHR …

Characterizing Intralaminar Distal Crack And Delamination In Multidirectional Laminates Under Low Velocity Impact: Modeling Approach With Ultrasound Testing Validation, Niildiip Chandraa, Rachel Van Lear, Arief Yudhanto, Yuqing Zhao, David A. Jack, Douglas E. Smith

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Multidirectional laminated composites are essential for load-bearing structures, especially under frequent impact loading. While existing modeling techniques simulate various impact damage modes, our understanding of the underlying mechanisms, specifically the initiation and progression of intralaminar distal cracks and interlaminar delamination, needs improvement. Validating these mechanisms is crucial for enhancing modeling accuracy and expediting the design process. In this work, we propose a three-dimensional finite element modeling (3D FEM) approach aimed at elucidating the impact damage mechanisms in multidirectional carbon fiber reinforced polymer (CFRP). Our model incorporates cohesive zone models (CZM) to simulate the behavior of intralaminar cracks at distal points …

Sift Feature-Based Relative Altitude Estimation Enhanced With Siamese Network, Shirin Nasr-Esfahani, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In GPS-denied environments or when GPS signals are unreliable or unavailable, alternative methods of accurate localization with coordinate generation become critical. To address localization, the scale-invariant feature transform (SIFT) algorithm, along with its numerous adaptations, is extensively utilized in computer vision and remote sensing for matching image features to identify objects and perform localization. This article presents a novel approach for estimating the relative altitude of unmanned aerial vehicles (UAVs) using SIFT features' scale (size), omitting the need for additional data like camera intrinsic parameters, as well as extensive image datasets are also required for training. Furthermore, the approach enhances …

Microwave Photonics-Assisted Interrogation Of Fiber-Optic Interferometric Sensors With Joint Frequency-Time Domain Analysis, Ruimin Jie, Jie Huang, Chen Zhu

Electrical and Computer Engineering Faculty Research & Creative Works

Fiber-optic interferometers are widely used in localized sensing applications due to their compact size, high sensitivity, and immunity to electromagnetic interference. In this paper, we propose and experimentally demonstrate a novel interrogation scheme for fiber-optic interferometric sensors, utilizing microwave photonics (MWP) and joint frequency-time domain analysis. As a proof of concept, a miniature fiber in-line Fabry-Perot interferometer (FPI) is integrated with a microwave photonic single-passband filter, enhanced by a dispersion compensation module to improve sensing performance. By applying an inverse Fourier transform to the system's complex frequency response, the time-domain representation of the signal is obtained, translating spectral shifts of …

Enhanced Multidimensional Harmonic Retrieval In Mimo Wireless Channel Sounding, Yanming Zhang, Wenchao Xu, A. Long Jin, Tianquan Tang, Min Li, Peifeng Ma, Lijun Jiang, Steven Gao

Electrical and Computer Engineering Faculty Research & Creative Works

This paper introduces a recursive parallel dynamic mode decomposition (RPDMD) scheme tailored for multidimensional harmonic retrieval (MHR), specifically applied to MIMO wireless channel sounding. The RPDMD algorithm is devised to address the complexities inherent in multidimensional scenarios, leveraging the dynamic mode decomposition (DMD) framework within a recursive parallel structure. Initially, the observed tensorial multidimensional harmonic data is transformed into a two-dimensional matrix format along the r-th dimension. Subsequently, DMD dissects this matrix data into eigenvalues and their associated modes. The real and imaginary components of the DMD eigenvalues yield damping factors and frequencies in the r-th dimension, respectively. Furthermore, recursive …

Miniaturized Wearable Biosensors For Continuous Health Monitoring Fabricated Using The Femtosecond Laser-Induced Graphene Surface And Encapsulated Traces And Electrodes, Homayoon Soleimani Dinani, Tatianna Reinbolt, Bohong Zhang, Ganggang Zhao, Rex E. Gerald, Zheng Yan, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Wearable sensors are increasingly being used as biosensors for health monitoring. Current wearable devices are large, heavy, invasive, skin irritants, or not continuous. Miniaturization was chosen to address these issues, using a femtosecond laser-conversion technique to fabricate miniaturized laser-induced graphene (LIG) sensor arrays on and encapsulated within a polyimide substrate. The femtosecond laser-converted conductive traces can have a size of 20 to 2 μm compared to the traditionally larger CO2 laser dimensions of around 300 to 100 μm. This marks a 93-98% decrease in trace size when using a femtosecond laser. This miniaturization allows for the ability to process temperature, …

Drta: Dynamic Reward Scaling For Reinforcement Learning In Time Series Anomaly Detection, Bahareh Golchin, Banafsheh Rekabdar, Kunpeng Liu

Computer Science Faculty Publications and Presentations

Anomaly detection in time series data is important for applications in finance, healthcare, sensor networks, and industrial monitoring. Traditional methods usually struggle with limited labeled data, high false-positive rates, and difficulty generalizing to novel anomaly types. To overcome these challenges, we propose a reinforcement learning-based framework that integrates dynamic reward shaping, Variational Autoencoder (VAE), and active learning, called DRTA. Our method uses an adaptive reward mechanism that balances exploration and exploitation by dynamically scaling the effect of VAE-based reconstruction error and classification rewards. This approach enables the agent to detect anomalies effectively in low-label systems while maintaining high precision and …

Scitopic: Enhancing Topic Discovery In Scientific Literature Through Advanced Llm, Pengjiang Li, Zaitian Wang, Xinhao Zhang, Ran Zhang, Lu Jiang, Pengfei Wang, Yuanchun Zhou

Computer Science Faculty Publications and Presentations

Topic discovery in scientific literature provides valuable insights for researchers to identify emerging trends and explore new avenues for investigation, facilitating easier scientific information retrieval. Many machine learning methods, particularly deep embedding techniques, have been applied to discover research topics. However, most existing topic discovery methods rely on word embedding to capture the semantics and lack a comprehensive understanding of scientific publications, struggling with complex, high-dimensional text relationships. Inspired by the exceptional comprehension of textual information by large language models (LLMs), we propose an advanced topic discovery method enhanced by LLMs to improve scientific topic identification, namely SciTopic. Specifically, we …

Formal Financing Of Small And Medium Scale Enterprises In Nigeria: A Path To Economic Development?, Kingsley Onyekachi Onyele, Eberechi Ikwuagwu, Innocent Umezurike

The Journal of Entrepreneurial Finance

This investigation assessed the influence of formal financing for small and medium-sized enterprises (SMEs) on the economic advancement of Nigeria, utilising annual time series data ranging from 1992 to 2022. Employing the Cobb-Douglas framework, control variables, including capital formation and labour, which could influence economic development, were incorporated into the empirical model to mitigate bias. Following initial tests for stationarity, it was determined that all variables achieved stationarity upon the first difference, a finding that validated the Vector Error Correction Mechanism (VECM) application. The analysis revealed that the credit extended to SMEs by commercial banks and the loans provided by …

Size Premium In Small Business Valuation: Analysis Of Closely-Held Firms, Craig S. Galbraith

The Journal of Entrepreneurial Finance

One of the most misunderstood components of valuing a small closely-held business is how to address the impact of small size. Most closely-held enterprises are relatively small in size, with market values less than $1million. Many small mom and pop operations, or single owner-operator family businesses, often have market values even smaller. The most common method to account for size is to use the size premium reports from Kroll or another financial data service provider. However, these small firm premiums are determined exclusively from publicly-traded firms, where even the category of the smallest publicly-traded firms are still magnitudes larger than …

The Game Of Going Public: Market Timing, Information Asymmetry, And The Signaling Effects Of Initial Public Offerings (Ipos) In The Technology Industry, Kiana Seva

Scripps Senior Theses

My thesis explores the game of going public in the technology industry, specifically the strategic decision-making process of issuing an initial public offering (IPO), the advantages a company may gain from its market timing, and the signaling effects of its IPO. Existing research on this subject is vast but fragmented into areas that focus on the decision to go public, game theoretical analysis of the advantages, analysis of the advantages using quantitative data, and signaling effects. To address this gap, I developed and analyzed three game theoretic models which account for all these factors that affect the success of an …

Severance As Metaserial Dystopia: Penal Spectatorship And Critical Reintegration, Sofia Buntz

Scripps Senior Theses

Typical prison media, while purporting to represent incarceration and its social meaning to the public, transforms lived realities of state-sanctioned violence into entertainment spectacle and operates under strict material and ideological constraints that prevent it from meaningfully questioning the legitimacy and function of the prison as a built institution. The television series Severance (2022), however, represents incarceration in the form of the dystopian office-prison where the innies are trapped, employing metaserial and science fictional narrative mechanisms to critically implicate the spectator. The show’s science fictional premise links the explicit violence of incarceration to the more subtle form of disciplinary control …

El Maíz Del Abuelo: Fidel Márquez Sanchez’S Legacy And Mexico’S Historical Maize Agriculture, Lucia Marquez-Uppman

Scripps Senior Theses

The Green Revolution was an era of scientific development in productive agricultural methods and technologies in the mid-twentieth century. High-yielding seed varieties, artificial fertilizers, irrigation infrastructure, pesticides, and herbicides all developed from this period. Texcoco, Mexico was the center of much of the Green Revolution's education and research from the 1940s onward at the Autonomous University of Chapingo, a prestigious agricultural school, with funding from the US-based philanthropic Rockefeller Foundation. Powerful consequences in the globe's agriculture emerged from the Green Revolution, including the production of maize, a staple crop in Mexico, especially for Indigenous and campesino populations. My abuelo, Fidel …

Achieving Public Goals Using Private Tools: Build-Operate-Transfer Projects In Southeast Asia, Angela J. Niederberger

Scripps Senior Theses

This thesis investigates the infrastructural challenges impeding economic development in Southeast Asia, with a particular focus on the energy and transportation sectors. It examines how Build-Operate-Transfer (BOT) models, a form of Public-Private Partnerships (PPP), have emerged as viable mechanisms to address the region’s persistent infrastructure deficits. Drawing from six case studies across Laos, Vietnam, and Indonesia—including successful and unsuccessful BOT initiatives—this research evaluates the financial, political, and administrative constraints that affect project outcomes. It further explores the role of institutional frameworks, international organizations, and legal reforms in enhancing BOT performance and mitigating risks such as corruption, capacity gaps, and public …

“From Craft To Collection: A Conservation Case Study On A Prisoner Of War Napoleonic Bone Model Guillotine”, Anna Shobe

Scripps Senior Theses

For my thesis, I have the ambition of creating a sort of guide on the treatment and analysis of this model guillotine, first by filling in some historical background about the object, informed by prisoner accounts and scholarship around similar Napoleonic bone models. As well as the materiality of the object, which will be discovered through instrumental analysis using a Microfadeometer to test for light sensitivity of the bone itself and the colored pigments present and a Scanning Electron Microscope/Energy Dispersive X-ray Spectroscopy to attempt to test for the classification of said pigments. These methods will not only inform the …

Constructing Bodies Of Subversion And Resistance: The Carceral Quarantine Of Hiv-Positive Haitian Refugees At Guantanamo Bay Under U.S. Imperialism, Isabelle E. Oringer

Scripps Senior Theses

This thesis investigates the detention of HIV-positive Haitian refugees at Guantánamo Bay in the early 1990s as a case study of medicalized racism and U.S. imperialism. It explores how U.S. public health policy, immigration law, and Cold War-era foreign interventions converged to criminalize and confine Black Haitian bodies, constructing them as threats to national security and public health. By analyzing primary testimonies and media coverage alongside the works of scholars such as Paul Farmer and Naomi Paik, the project reveals how racialized conceptions of disease and subversion informed discriminatory practices that disproportionately targeted Haitian refugees. Furthermore, it examines how the …

Die Baukästen Des Bauhauses: Futurität Und Affekt In Entwürfen Von Alma Siedhoff-Buscher, Clara R. Louden

Scripps Senior Theses

In den frühen 1900er Jahren manifestierte sich die wachsende Besorgnis über Kinder und ihre Entwicklung in den Arten von Spielzeug, die entwickelt und vermarktet wurden. Die Entwürfe von Alma Siedhoff-Buscher, einer Bauhaus-Schülerin, verkörpern am besten die Zukunftsorientierung der Designschule und die latenten Ängste, die um die nächste Generation kreisen. Durch die Analyse ihres Schiffbauspiels und des Kinderspielschranks werden die Fragen nach Normalität, Kreativität und dem „richtigen“ Kind deutlich.

Shaping National Subjects: Recognition, Subjectivity, And Governmental Philosophies In Finnish And Singaporean Education, Katherine S. Cherney

Scripps Senior Theses

Examining the divergent educational systems of Finland and Singapore, two nations achieving consistently high PISA rankings, reveals how distinct governmental philosophies and recognition methods cultivate different forms of subjectivity in students. Recognition is how individuals, including students and educators, are acknowledged and valued within educational systems, influencing self-perception and identity. Subjectivity pertains to how individuals understand themselves and their existence within the academic and national order, encompassing agency, beliefs, and sense of self relative to norms and power structures. Analysis utilizes theoretical frameworks from Judith Butler, Paulo Freire, Jacques Rancière, Henry Giroux, and Michel Foucault to explore power dynamics, subjection, …

A Song Of Soil And Seeds: The Delicious History Of Tunisian Grain Agriculture And Its Solution To Contemporary Food Scarcity., Ella Schonberger

Scripps Senior Theses

“A Song of Soil and Seeds: The Delicious History of Tunisian Cereal Agriculture and Its Solution to Contemporary Food Scarcity” by Ella Schonberger explores the history of Tunisian grain agriculture as a continuous narrative of adaptation, resilience, and colonial disruption. This thesis traces the historical journey of Tunisian grain agriculture, from its indigenous Amazigh roots through successive waves of Roman, Ottoman, and French agro-colonialism, to the environmental and agricultural pressures of the Green Revolution and today’s climate crisis.

Combining archaeological evidence, historical records, agronomic research, oral interviews, and firsthand culinary experimentation, this paper examines how Tunisia’s heirloom grains—sorghum, millet, and …

A Perspective On Imbalance: A Memoir Through The Lens Of Eating Disorders Anonymous, Samantha C. Lasky

Scripps Senior Theses

A Perspective on Imbalance uses a crab shell essay format within the adjusted framework of Eating Disorder Anonymous’ “Perspective on Balance” letter. This original letter speaks to how physical, social/emotional, and spiritual balance came to exist in the founder’s life after working the 12 steps of the program, but the author of this thesis felt more inclined to examine what life looks like in each of those categories before the 12 steps, as well as what happens when you choose not to work them (as this has been her experience thus far). The resulting linear prose essay includes themes of …

Geographies Of Freedom: Marronage, Slavery, And Black Cosmopolitanism In The Early North American Borderlands, Gemma K. Lynch

Scripps Senior Theses

This thesis reconceptualizes the colonial U.S. South through the lens of the Atlantic World, revealing the mobility, and influence of Black actors. It emphasizes the role of Black people who, rooted in Africa and dispersed across the American colonies, developed and used a cosmopolitan understanding of the Atlantic to negotiate their freedoms. Focusing on Spanish Florida, Georgia borderlands, and French New Orleans, it unveils how enslaved Africans and their descendants navigated and exploited imperial conflicts between British, Spanish, French, and Native Americans. By uncovering the linkages between the colonial Southeast and contextualizing them with the greater Caribbean, this study reframes …

Sticking Out And Fitting In: Experiences Of Black And Asian Pacific Islander Desi American Students At Scripps College, Grace Njoki Gitau

Scripps Senior Theses

There is a lack of research about the experiences of students of color at predominantly white women’s colleges. Women’s colleges are institutions that have evolved over hundreds of years to support the education of marginalized genders, including transgender women and nonbinary people in recent years. Many women’s colleges have a white majority of students, which can have adverse effects on students of color pursuing their education. Collecting data from Scripps College, a women’s college with 40% students of color, 12 interviews were conducted with students who self-identified as Black or Asian American. Results found that students of color who experience …

Finding Futures: Refusing Canva And The Homogenization Of The D.I.Y. Political Post(Er), Cassidy Bensko

Scripps Senior Theses

The convergence of corporate technology and subversive political expression is not new. Canva, like Xerox, is but another made-for-the-office technological innovation employed to political ends. Its ease-of-use has made it a staple tool for students, office workers, event planners, and political organizers alike. However, it is easy to use because it eliminates the need for creative decision-making, empowering users to quickly and easily produce designs that all look the same. This paper asks: Is the homogenization of D.I.Y. political posters, a medium that has historically been characterized by design elements that are as subversive as the politics they represent, indicative …

“Ignorance Is No Excuse”: Reproducing The Normative Female Body Through Mass Consumerism In Post-Wwii Women’S Magazines, Hannah E. Lorenz-Meyer

Scripps Senior Theses

In the Post-War era, women’s magazines took on a key role in cultural production, publishing literature, non-fiction articles, and advice on everything from marriage to fashion. Women’s magazines served a a form of propaganda, promoting a specific form of femininity that upheld the status quo. And that form of femininity was overwhelmingly affluent and White. By establishing magazines as a solution to women’s personal problems, editors served to shape the image of the post-war American woman. Nowhere is this vision more intimate than the way it was applied to the female body and reproduction. In this thesis, I analyze how …

Preserving The Stolen: Cultural Appropriation And The Case Of Seattle's Totem Pole, Olga S. Koutroulis

Scripps Senior Theses

This thesis investigates the cultural appropriation and conservation of the Chief-of-All-Women totem pole, originally stolen by Seattle businessmen from the Tlingit village of Tongass in 1899 and later reinstalled in Pioneer Square as a symbol of the city. By framing the totem pole as a site of both physical and cultural displacement, I trace its journey from sacred object to public monument, and ultimately to federally funded replica. Drawing on conservation theory, oral history, archival research, and an interview with Haida artist Sondra Segundo, I argue that the pole’s removal, replication, and continued display reflect broader patterns of settler colonialism …

A Proof Of Np-Completeness For The K-Means Clustering Algorithm, Brooke C. Feinberg

Scripps Senior Theses

The k-means clustering algorithm is one of the most widely used clustering techniques in data analysis and machine learning, yet its exact computational complexity remains subject to ongoing theoretical investiga- tion. This work establishes the NP-completeness of k-means by proving (1) it is NP-hard and (2) it lies in NP. To demonstrate NP-hardness, we construct a series of polynomial-time reductions from well-known NP-complete problems. Specifically, we reduce 3sat to Vertex Cover, and then reduce Vertex Cover to k-means, thereby establishing the computational hardness of the k-means clustering problem. We then prove k-means is in NP, and thus conclude it is …

New Insights Into Fertilisation With Animal Manure For Annual Double-Cropping Systems In Nitrate-Vulnerable Zones Of Northeastern Spain, Dolores Quilez, Monica Guillen, Marta Valles, Arturo Dauden, Beatriz Moreno-Garcia

Biological and Agricultural Engineering Faculty Publications and Presentations

Maize double-cropping production systems in Mediterranean areas have a great nitrogen extraction capacity and high nitrogen (N) requirements. This study aims to assess whether in these farming systems, animal manure can be applied, using adequate management practices, at levels exceeding the maximum annual amount of livestock manure established in the European Nitrate Directive for vulnerable zones (170 kg N ha-1) without increasing the risk of water nitrate contamination. We compare the risk of nitrate leaching under two fertilisation strategies, one with synthetic fertilisers and the second with a maximised application of pig slurry, exceeding the limits of the EU Nitrate …