MORP: Monocular Orientation Regression Pipeline

Orientation estimation of objects plays a pivotal role in robotics, self-driving cars, and augmented reality. Beyond mere position, accurately determining the orientation of objects is essential for constructing precise models of the physical world. While 2D object detection has made significant strides, the field of orientation estimation still faces several challenges. Our research addresses these hurdles by proposing an efficient pipeline which facilitates rapid creation of labeled training data and enables direct regression of object orientation from a single image. We start by creating a digital twin of a physical object using an iPhone, followed by generating synthetic images using the Unity game engine and domain randomization. Our deep learning model, trained exclusively on these synthetic images, demonstrates promising results in estimating the orientations of common objects. Notably, our model achieves a median geodesic distance error of 3.9 degrees and operates at a brisk 15 frames per second

Mapping issue salience divergence in Europe from 1945 to the present

Issue salience is a fundamental component of party competition, yet we know little about when, where, or why parties’ issue emphases converge or diverge. I propose an original operationalization of issue salience divergence, the extent to which parties’ issue emphases differ from each other in an election, that generates values at the party-election and country-election levels. I leverage data from party manifestos to calculate scores for 2,308 party-election combinations of 381 unique parties in 426 elections across thirty European countries, the most comprehensive dataset to date. I find that issue salience divergence is generally low and has starkly decreased over time, but countries and parties differ substantially. As an initial step in understanding these differences, I propose and test initial expectations of how party and democracy age, electoral systems, and party type alter the incentives for divergent issue salience

Private education and inequality in the knowledge economy

This article explores the consequences of public and private spending on education at all levels, looking at skills and income inequality. We use data for 22 affluent democracies from 1960 or 1995 (depending on data availability) to 2017. High levels of public education spending consistently lower income inequality, both measured as wage dispersion and as the education premium. In contrast, higher levels of private education spending are associated with both higher wage dispersion and a higher education premium. We show that this effect works in part through differential skills acquisition. Public education spending raises the math scores of 15-years old students at the mean and at the 25th percentile, but private education spending has no effect on skills at these levels. We find the same pattern among skills of adults; public education spending raises skills at the 25th percentile and the mean; private spending has no effect. Finally, we also show that higher levels of adult skills indeed depress the education premium

When Does Income Inequality Cause Polarization?

Income inequality has increased across developed democracies in the past thirty years (Piketty, 2014). Conventional wisdom suggests that high income inequality should be associated with political parties taking polarized positions as the left struggles to increase redistribution to its relatively poor voters while the right aims to entrench the position of economic elites (Meltzer and Richard, 1981; Han, 2015; Winkler, 2019). However, this general argument masks substantial within-country and cross-sectional variation. I argue that the connection between party positions and income inequality is contingent upon the construction of partisanship and the content of national elections. This thesis uses data from European national elections from 1996 to 2016 to show that when partisanship is expressed along economic lines - as indicated by a high degree of income differentiation between parties - and when economic issues are salient, the predicted effect of income inequality holds. When these factors are weak, however, income inequality has no discernible relationship with polarization.Master of Art

PARTY BRANDS AND POLITICAL CHANGE

This dissertation examines the long-term development of party brands in advanced democracies and their implications for party strategy and citizens’ engagement with democratic politics. Today, European electorates and party systems are at their most volatile since the Second World War, citizens are less likely to participate in elections, and most of the parties that built the thirty golden years of capitalism and democracy across the West are in retreat. Although many factors have contributed to this change, this dissertation focuses on the extent to which parties, particularly mainstream parties, have struggled to maintain distinct images in voters’ minds and how those images affect public opinion and voter behavior. The first study calculates issue salience divergence—the extent to which parties’ issue emphases diverge—for thirty European countries from 1945 to 2021. By moving beyond country case studies, I am able to identify that issue salience divergence has declined in most European countries. I also identify the effect of the electoral system and party type. The second study assesses the implications of issue salience divergence on the public. First, I verify that citizens notice greater differences between parties when issue salience divergence is elevated. Then, I use mediation analysis to chart the effect of issue salience divergence on satisfaction with democracy and self-reported voter turnout. Low levels of issue salience divergence depress both outcomes. At high levels, turnout becomes more likely, but the relationship between party differences and satisfaction is non-linear, with the most satisfaction occurring at intermediate levels of differentiation. The third study argues that party brands structure the returns to ambivalent and ambiguous electoral appeals. Because ambiguity allows voters to default to their priors, i.e., the party’s brand, they can be used effectively on issues that are central to a party’s brand. Ambivalence, however, signals potential brand deviation. Using an online survey experiment, I identify heterogeneous responses across issues’ brand centrality, appeal type, and the respondent’s partisanship. Together, these studies indicate that parties have become less distinct in the issues they emphasize, electorates incorporate these changes into their decision-making processes, and party brands constrain parties’ strategic opportunities.Doctor of Philosoph

Floquet exceptional contours in Lindblad dynamics with time-periodic drive and dissipation

The dynamics of an isolated quantum system is coherent and unitary. Weak coupling to the environment leads to decoherence, which is traditionally modeled with a Lindblad equation for the system's density matrix. Starting from a pure state, such a system approaches a steady state (mixed or otherwise) in an underdamped or overdamped manner. This transition occurs at an eigenvalue degeneracy of a Lindblad superoperator, called an exceptional point (EP), where corresponding eigenvectors coalesce. Recent years have seen an explosion of interest in creating exceptional points in a truly quantum domain, driven by the enhanced sensitivity and topological features EPs have shown in their classical realizations. Here, we present Floquet analysis of a prototypical qubit whose drive or dissipator strengths are varied periodically. We consider models with a single dissipator that generate global loss (phase damping) or mode-selective loss (spontaneous emission). In all cases, we find that periodic modulations lead to EP lines at small dissipator strengths, and a rich EP structure in the parameter space. Our analytical and numerical results show that extending Lindblad Liouvillians to the Floquet domain is a new, potentially preferred route to accessing exceptional points in the transient dynamics towards the Lindblad steady state.Comment: 4 figures, 7 page

Differentiated State of Initiating Tumor Cells Is Key to Distinctive Immune Responses Seen in H-Ras

Heterogeneity in tumor immune responses is a poorly understood yet critical parameter for successful immunotherapy. In two doxycycline-inducible models where oncogenic H-RasG12V is targeted either to the epidermal basal/stem cell layer with a Keratin14-rtTA transgene (K14Ras), or committed progenitor/suprabasal cells with an Involucrin-tTA transgene (InvRas), we observed strikingly distinct tumor immune responses. On threshold doxycycline levels yielding similar Ras expression, tumor latency, and numbers, tumors from K14Ras mice had an immunosuppressed microenvironment, whereas InvRas tumors had a proinflammatory microenvironment. On a Rag1-/- background, InvRas mice developed fewer and smaller tumors that regressed over time, whereas K14Ras mice developed more tumors with shorter latency than Rag1+/+ controls. Adoptive transfer and depletion studies revealed that B-cell and CD4 T-cell cooperation was critical for tumor yield, lymphocyte polarization, and tumor immune phenotype in Rag1+/+ mice of both models. Coculture of tumor-conditioned B cells with CD4 T cells implicated direct contact for Th1 and regulatory T cell (Treg) polarization, and CD40-CD40L for Th1, Th2, and Treg generation, a response not observed from splenic B cells. Anti-CD40L caused regression of InvRas tumors but enhanced growth in K14Ras, whereas a CD40 agonist mAb had opposite effects in each tumor model. These data show that position of tumor-initiating cells within a stratified squamous epithelial tissue provokes distinct B- and CD4 T-cell interactions, which establish unique tumor microenvironments that regulate tumor development and response to immunotherap

Maximum union-free subfamilies

An old problem of Moser asks: how large of a union-free subfamily does every family of m sets have? A family of sets is called union-free if there are no three distinct sets in the family such that the union of two of the sets is equal to the third set. We show that every family of m sets contains a union-free subfamily of size at least \lfloor \sqrt{4m+1}\rfloor - 1 and that this bound is tight. This solves Moser's problem and proves a conjecture of Erd\H{o}s and Shelah from 1972. More generally, a family of sets is a-union-free if there are no a+1 distinct sets in the family such that one of them is equal to the union of a others. We determine up to an absolute multiplicative constant factor the size of the largest guaranteed a-union-free subfamily of a family of m sets. Our result verifies in a strong form a conjecture of Barat, F\"{u}redi, Kantor, Kim and Patkos.Comment: 10 page

Vibration-Heating in ADR Kevlar Suspension Systems

The cryogenics group at NASA's Goddard Space Flight Center has a long-standing development and test program for laboratory and space-flight adiabatic demagnetization refrigerators (ADRs). These devices are used to cool components to temperatures as low as 0.05 K. At such low temperatures the ADR systems can provide a few micro-Watts of cooling power, so it is important to minimize the conduction of heat to these cold stages from the surroundings. The cold ADR elements are held in place by thin tensioned strings made of Kevlar, chosen for its high strength and stiffness and low thermal conductivity. During laboratory testing, we have observed that occasional significant additional heat loads on the coldest ADR stages correlate with unusually high vibration levels in the cryostat due to a noisy mechanical cryocooler. We theorized that this heat results from plastic deformation of the Kevlar fibers and frictional interactions among them, driven by the cryostat vibrations. We describe tests and calculations performed in attempt to confirm this source of the heating, and we discuss possible strategies to reduce this effect in future ADR suspension systems

Postpartum behaviour as predictor of weight change from before pregnancy to one year postpartum

<p>Abstract</p> <p>Background</p> <p>Postpartum weight retention affects many women and increases the risk of becoming overweight. The research objective was to study modifiable factors contributing to weight change at one year postpartum.</p> <p>Methods</p> <p>In this prospective cohort, postpartum behavior, such as physical activity, sedentary behavior, sleep, and intake of total energy, total fat and saturated fatty acids of 118 Dutch women were assessed in 2003/2004 by self-report at 6 weeks, 6 and 12 months postpartum. Mean postpartum scores were computed for the behavioral measures. In linear regression models it was determined which factors were associated with average weight change from before pregnancy to one year postpartum. Furthermore, factors associated with substantial postpartum weight retention (≥ 5 kg) were also studied in logistic regression models.</p> <p>Results</p> <p>At one year postpartum, the average weight of participants had increased by 0.9 kg (SD 4.4). Moreover, 20% of the women retained ≥ 5 kg. Women who perceived themselves more physically active than others were almost ten times less likely to retain ≥ 5 kg than women who perceived themselves equally active (OR = 0.11, 95%CI: 0.02 - 0.66). Exceeding the guideline for saturated fatty acid intake (OR = 3.40, 95%CI: 1.04 - 11.11), total gestational weight gain (OR = 1.14/kg, 95%CI: 1.01 - 1.27), and not having completed post high school education (OR = 5.13, 95%CI: 1.66 - 15.90) increased the odds of retaining ≥ 5 kg.</p> <p>Conclusions</p> <p>Since one in five women had substantial weight retention postpartum, effective interventions for the prevention of weight retention are much needed. Future studies should evaluate whether interventions focusing on the identified modifiable postpartum factors are successful in reducing weight retention after childbirth.</p