VictorJuiz/thesis huggingface dataset:
Optimization Models for Kidney Paired Donation
Keywords: Branch-and-Price
Decision Diagrams
Integer Programming
Kidney Paired Donation
Large Scale Decompositions
Robust Optimization

Kidney paired donation is a living-donor transplantation scheme allowing patients with end-stage renal disease to get a compatible donor when their own is not a match. Compatibilities among donors and patients can be modelled in a digraph, whose vertex set represents a donor with or without a paired patient and an arc depicts compatibility between donors and patients. Kidney allocation in this context consists of finding a matching, i.e., a set of vertex-disjoint cycles and chains. Despite the broad attention that kidney paired donation has received, some questions at algorithmic, operational and managerial levels remain open. This dissertation addresses the design and analysis of more realistic matching models in settings of real-world interest. This dissertation investigates new techniques from large-scale optimization to solve existing and new research questions on kidney allocation within the scheme of kidney paired donation. The central thesis of this dissertation is that optimization methods can assist kidney paired donation in the search of equitable, policy-wise flexible, failure-aware and computationally tractable kidney allocation in static and dynamic settings. Throughout this work, we address this thesis by designing novel models and solution methodologies to decide on what actions to take, when to take them and the mechanisms to protect allocation decisions from failure. Our first project presents the first branch-and-price algorithm to successfully integrate short-long cycles and chains. Empirical evidence shows the importance of long chains in creating more matching opportunities for hard-to-match patients. The second project addresses uncertainty in a two-stage optimization framework, whose solution approach is the first to address both homogeneous and non-homogeneous failure and offers flexibility on the policies that allow a failed matching to be repaired. Our algorithms for the first two chapters outperform the state of the art in their domain on publicly available instances. The last project studies the long-term implications of selecting a deterministic and robust solution in a dynamic setting using simulation.
Advanced Microscopy to Investigate Nanoparticle Transport Mechanism
Keywords: Nanoparticle delivery
Nanotechnology
Protein corona
Tumour-associated macrophage

Nanoparticles are used as delivery platforms for cancer therapeutics or imaging agents to tumours. However, the translation of nanoparticle therapy is hindered by the limited understanding of the transport of nanoparticles in the body. Recent advancements have shown that cellular mechanism dictates the transport of nanoparticles. In my thesis, I examine 1) locally released platelet factor 4 in injured blood vessels leads to local uptake of nanoparticles in the endothelial cells; 2) the new mechanism of nanoparticle transport by tumour-associated macrophage migration; 3) the contribution of macrophage-mediated transport of nanoparticles over passive diffusion. The knowledge presented in this thesis will help guide future nanoparticle design and therapeutic by 1) manipulating the protein adsorption to tune the uptake in cells and 2) utilizing the different mechanisms of transport to improve nanoparticle distribution in the tumour microenvironment.
Frankenbike Re-imagined for Percussion Quartet and Electronics
Keywords: bicycle
percussion
sound installation

Frankenbike re-imagined is an audio-visual installation of instruments built from re-purposed scrap metal bike frames and parts. This interactive installation explores the points of control on a bike and uses them in a tactile way to generate sound. The main components of the installation are the rotation of the drivetrain system and its counterparts, the tension of the cable and spoke systems, and engaging with the external components as percussive found sounds. It modifies them to enhance the sounds they naturally produce, creating a sonic landscape from mechanical gestures. The installation contains a main structure of two bike frames balancing on each other, and two additional mechanic stands holding suspended resonant objects. The installation uses a combination of contact, close, and external microphones for amplification, pedal effects for signal processing, and stereo output. Frankenbike re-imagined can be presented in two versions—in a concert setting with an accompanying score for percussion quartet, or in a gallery space as an interactive installation. Urban bike culture has its roots in living sustainably and economically. Bike commuting has gained popularity as a low-cost and ecological alternative to driving or taking public transportation. Connecting to these themes, Frankenbike re-imagined was built entirely from re-purposed parts—all materials used were either damaged or not suitable for reuse. The installation seeks to give them a life other than being discarded as scrap metal, existing beyond the purpose for which they were intended. Do-It-Yourself culture is also prevalent amongst city bike riders as an affordable option for bike repair, as well as to learn the skills necessary to do your own bike maintenance. Refurbishing older bikes, as well as building bikes entirely from used parts, are also low budget options. Currently I work as a mechanic in a bike repair shop where I am constantly listening to these mechanical sounds when I work. I often consider the relationship of these sounds to their functions—a sound often signifies a problem in the system that needs to be corrected, and a quiet bike usually indicates a well functioning bike. Through this project I seek to embrace these imperfections and re-imagine my mechanical skills for creative applications.
On the Structure of Information Cohomology
Keywords: Entropy
Homological Algebra
Information Theory
Lattice
Operads
Order Theory

We study the cohomology of information structure. Specifically, we formulate and prove analogues to results from other cohomology theories, and use order theory (specifically lattice theory) to obtain information-specific results. We then apply those results. The homological nature of Shannon entropy has been a subject of interest to some for well over fifty years, and yet new approaches are still being suggested and studied. Most recently, P. Baudot and D. Bennequin, and later J. P. Vigneaux have approached this using topoi whose cohomology of Ext functors contain the entropy function as a 1-cocycle. Moreover, both sets of authors have proven, under some conditions on their respective constructions, that the entropy in fact generates all of H^1. This leaves open questions regarding the general structure (algebraic and categorical) of information structures and the possible higher order cocycles. This thesis is aimed at extending the theory behind the constructions of J. P. Vigneaux. In particular, we produce new results arising as analogues to results from other cohomology theories, namely: - The Mayer-Vietoris long exact sequence, to allow for decomposition of information structures into closed information structures; - Shapiro's lemma, to allow for some novel elementary computations, and lastly; - The Hochschild-Serre spectral sequence, to allow for cohomology computations by means of sub- and quotient structures. We also provide structural results of algebraic and order-theoretic nature: we provide means to produce useful projective and injective sheaves over information structures, and furthermore prove a general structural result for projective sheaves. This enables easy computations of projective and injective resolutions that provide novel bounds on the cohomological dimension of information structures. Additionally, by taking into account the order-theoretic nature of information structures, we are able to produce an improved bound based on combinatorial invariants. We finally utilise our results to study the second cohomology groups of some information structures and, in one particular case of interest, find new families of 2-cocycles. Lastly, we provide the alternative perspective in which we can view entropy function as a 1-cocycle by investigating it through the lens of operads rather than topoi. We prove that, in this new theory also, the Shannon entropy generates H^1.
Increasing the Efficiency of Electrochemical Nitrogen Fixation by Using a Direct Nitrate-to-Urea Pathway
Keywords: ammonia synthesis
C-N coupling
CO2 reduction
electrocatalysis
nitrate reduction
urea synthesis

With the increasing demand and application of nitrogen fertilizers, electrochemical urea synthesis from CO2 and NO3- is seen as a great alternative to bypass heavily fossil fuel-based production and remediate agricultural leaching. However, urea synthesis remains underdeveloped with a handful of existing literature due to the lack of understanding of reaction conditions. This thesis summarizes my efforts to understand nitrogen electrochemical reduction (Chapter 2), carbon dioxide reduction (Chapter 3), and the combination of two reactions to synthesize urea (Chapter 4). Chapter 2 describes a strategy to improve nitrogen conversion to ammonia catalytic performance via catalyst facet design. We challenged conventional wisdom and found that smooth low-energy facets outcompete irregular high-energy facets on nickel sulfide catalysts. Chapter 3 describes a carbon dioxide conversion project with molecular catalysts to understand CO2 reduction in aqueous systems. We showed adjusting terminal functional groups on metalloporphyrins could affect the electron density on the metal center, thus further altering the reaction pathway. Chapter 4 initially describes our experience in reproducing early studies results, the electrolyte impacts on urea electrosynthesis, and limitations on previous urea detection methods. Initially, we concluded urea synthesis is achievable on a copper catalyst with small current densities and proper electrolyte conditions. NO3- concentration is the most impactful factor and can vary urea selectivity from 0% to 50%. NO2- is observed as the major competing product under small bias and shares a scaling relationship with urea. In the second part of Chapter 4, we demonstrate that limitations in the current colorimetric and 13C NMR methods can lead to false conclusions, which overthrow our previous results. We provide guidelines for reliable urea detection and advocate liquid chromatography-mass spectrometry (LC-MS) as the ultimate detection method due to its high sensitivity for ppm-level urea and isotope-coupled resolving ability. By using a simple LC-MS protocol, ppm-level urea concentrations can be firmly proven with/without isotope labeling reactants.
Achievement and Mental Well-Being in Post-Secondary Education (PSE) Students with Attention Deficit Hyperactivity Disorder (ADHD)
Keywords: Achievement
Attention Deficit Hyperactivity Disorder (ADHD)
Leisure activities
Mental Well being
Physical Activity
Resilience

Disproportionately few young adults with Attention Deficit Hyperactivity Disorder (ADHD) are admitted to post-secondary education. If admitted, they are more likely to withdraw from classes or fail to graduate, relative to post-secondary education (PSE) students without ADHD. They are reported to have lower levels of academic self-efficacy, confidence, and competence levels, which ultimately affect their overall achievement and Mental Well-being. Recommended treatments for people with ADHD typically include medication, accommodations to their learning environment, cognitive behavioural therapy, and social supports. In this study, 96 PSE students attending undergraduate and graduate programs at a Canadian university completed surveys to gauge their Mental Well-being, to estimate their current achievement (GPA), and the extent of their ADHD symptoms. They also completed open-ended questions about their physical activity levels, leisure activities, social supports, and coping strategies. Of the 96 participants, 75 responded to the surveys after the start of the COVID-19 pandemic lockdowns. The results showed the effects of physical activity, social supports and coping strategies, and a negative correlation of self-reported symptomology, on the Mental Well-being and achievement scores of the participants. The responses of the majority of those who completed the survey during the COVID-19 pandemic lockdown also demonstrated adaptations and coping strategies that were strength-based, and that indicated resilience and self-determination. The findings suggest that more emphasis should be placed on supporting the self-determination of this population.
Moral Conflict and Socialization
Keywords: Millennial
Moral conflict
Moral development
Polarization
Social Movements
Socialization

Growing polarization in civil society has motivated scholars to explore the sources of conflict. While top-down explanations emphasizing opportunistic political leaders and changes to media structures have been instructive, micro foundations from the bottom-up remain comparatively less understood. This dissertation addresses the topic by bringing socialization into the fold. I argue that understanding the cleavages and dynamics of political conflict in post-industrial society requires examining reproduction of those moral orientations that underlie it. The dissertation comprises of three studies that elaborate this theme in different ways. Collectively, they focus on a cohort of US Millennials born between 1986-1990 and apply longitudinal data analysis to nationally representative sample following their transition from adolescence into early adulthood (2002-2013). Each chapter takes a staple topic in political sociology as its entry point. Chapter two revisits earlier collective behaviour theories on alienation and social movements. Against current wisdom, the analysis finds that alienation in the forms of meaninglessness and social isolation are among the strongest predictors of participation in populist movements of both left-wing and right-wing persuasions. Chapter three examines moral socialization in higher education with an eye to ‘culture war’ conflict. It challenges the self-selection hypothesis by finding evidence of substantial moral change. Students mostly move in a liberal direction, prioritizing individual harm reduction over traditionalism and come to believe morality ought to be reformed to reflect social changes. They depart from the typical liberal profile on moral relativism, however, by becoming increasingly assured of definite rights and wrongs. Chapter four explores social reproduction of expressive individualism – a moral orientation valorizing change over conservation. While modernization theory treats expressivism as an aggregate phenomenon, the study finds that diffusion proceeds more unevenly, affecting the population at differential rates. Reproduction involves both continuity and conflict: expressive orientations can be transmitted through liberal aesthetic upbringings but are also associated with parent-child conflict where explicit parental transmission isn’t required.Taken together, the studies unpack the micro foundations of polarization by situating moral orientations underlying conflict and change at the tail-end of early-life enculturation processes.
The Helping Paradox: Understanding the Psychological and Emotional Effects of Bystander Intervention in Situations of Sexual and Dating Violence on Campus
Keywords: Bystander Intervention
Dating Violence
Intimate Partner Violence
Mental Health
Sexual Violence
Student mental health

Prevalence of gender-based violence (GBV) on postsecondary school campuses is a major public and institutional concern. Effective prevention includes bystander intervention training, which fosters a culture of responsibility among community members for each other’s safety. Bystanders’ prosocial response is critical for reducing harm, though little is known about the mental health impacts of intervention on student bystanders. This study’s purpose was to: 1) examine the psychological and emotional effects student bystanders to GBV experienced; 2) identify individual and situation-specific factors influencing these outcomes; and 3) determine the role of effects on intentions to help in the future and to participate in intervention training. Participants were students at Canadian postsecondary schools who indirectly encountered sexual or dating violence during their tenure (N = 126). The study relied on a cross-sectional design and was conducted via online survey. Measures assessed psychological and emotional experiences and reflected underlying theoretical constructs of vicarious trauma (VT), secondary traumatic stress (STS), and vicarious posttraumatic growth (VPTG). More bystanders intervened (n = 100) than not (n = 26), often in situations perceived as serious and when closely connected to the victim involved. Participants reported positive and negative psychological and emotional effects. Multivariate analyses investigating differences in impacts between groups revealed a mediation model; variables related to incident seriousness, validation, and confusion explained the relationship between intervention behaviour and outcomes. Upon further exploration of predictors, regression analyses also identified bystanders’ personal GBV history and self-mastery influenced outcomes. Positive feelings and perceived ineffectiveness in bystander action emerged as significant positive predictors of most outcomes, though the latter had greater influence on negative psychological and emotional effects. Moreover, bystanders’ willingness to help in the future and to partake in training were affected by their intervention behaviour and some psychological and emotional experiences. This study contributes to a deeper understanding of the ripple effect of trauma on students indirectly exposed to GBV, including the factors associated with their experiences of VT, STS, and VPTG. Findings underscore the importance of intervention training to improve bystanders’ knowledge and skills to respond effectively when confronted with an incident and perhaps lessen potential adverse impacts.
Real-time Hybrid Simulation with Higher-fidelity Numerical Substructure: Methodology, Implementation, and Application
Keywords: adaptive controller
concentrated plasticity
gyromass damper
multi-rate
real-time hybrid simulation

Real-time hybrid simulation (RTHS) is an efficient experimental testing technique proposed for the seismic evaluation of structures. In RTHS, structural components that are challenging to characterize numerically are physically tested using actuators, known as the experimental substructures, while the remaining part is numerically modeled, referred to as the numerical substructure. The real-time execution mode of RTHS enables the capture of rate-dependent behaviors, but it also presents challenges in actuator control for the experimental substructure and computational efficiency for the numerical substructure. To address these limitations, this study proposes outer-loop controllers to minimize tracking errors while applying target displacement to the experimental substructure during testing. An adaptive phase-lead compensator (APLC) supplemented with a proportional-integral-derivative controller has been introduced to enhance the performance of the actuators in trajectory tracking and applied to study a benchmark control problem defined for RTHS. Following the adaption logic of APLC, a model-based adaptive outer-loop controller, namely an adaptive discrete feedforward controller (ADFC), formulated as the inverse of the transfer function model of the servo-hydraulic loading system in RTHS, has been proposed. Additionally, a computational tool, namely Hybrid2D, optimized for real-time execution, has been developed to enable a concentrated plasticity model in RTHS, improving the fidelity of the numerical substructure. Modeling theory, along with the procedure to interface the Hybrid2D with real-time targets, is elaborated. To address the challenge when the complexity and the number of the computational degrees of freedom (DOFs) of the numerical substructure exceed the limit of computational hardware, multi-rate RTHS (mrRTHS) has been introduced, where the actuator control with experimental substructure and the computation with numerical substructure are executed at different rates. After investigating the data transmission within mrRTHS, the proposed ADFC is applied to compensate for the experimental errors in mrRTHS. In the end, an mrRTHS example, which investigates the seismic performance of a nine-story five-bay base-isolated structure controlled by gyromass dampers, is conducted to demonstrate the effectiveness and potential of the proposed ADFC, Hybrid2D, and mrRTHS implementation strategy in facilitating the application of RTHS in complex structural systems.
Fair and Efficient Social Decision Making
Keywords: algorithmic fairness
computational social choice

Algorithms have had a remarkable impact on human. Consequently, it is more important than ever to design decision-making algorithms that treat people fairly, use limited resources efficiently, and foster social good. We contribute toward this direction by optimizing decision-making for social good, analyzing and recommending improvements to methods of civic participation, and suggesting novel notions of fairness for domains like machine learning and peer review. In Part I, we focus on optimizing decision-making for social good in two real-life applications. First, we consider the problem of allocating pooled diagnostic tests during an epidemic. We design novel algorithms that approximately maximize the social welfare and complement our theoretical results with experiments on real data. Second, we analyze the effect of different grading systems on student performance and identify conditions under which certain grading systems are optimal. In Part II, we study three approaches used to increase civic participation. The first approach, called sortition, is based on the idea of choosing representatives for decision-making by lot. We suggest selection algorithms that satisfy fairness and efficiency guarantees. The second approach, called participatory budgeting, engages citizens in decision-making by having them vote on the allocation of limited public resources. We formalize the idea of individual fairness in participatory budgeting and study to what extent it can be guaranteed. The last approach is to conduct polls for an election to betterengage citizens, and we study the effectiveness of polls for predicting the outcome of ranked-choice elections. In Part III, we leverage the economic literature to propose meaningful notions of fairness for novel application domains. First, inspired by the idea of core in economics, we provide approximate fairness guarantees for clustering. Second, we utilize Nash welfare from welfare economics to design fair algorithms for a multi-agent variant of the classical multi-armed bandits problem. Third, we adopt a popular fairness notion from the fair division literature, namely envy-freeness, to two-sided matching markets. Fourth, we also import core, to the problem of reviewer assignment and to the problem of teamformation.