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Impact on Civilians from RSF Attack on Wad al Noura, June 5, 2024
Get PDFThis report details an attack on June 5, 2024 by the Rapid Support Forces (RSF) on and around Wad al Noura, Al Jazirah State and identifies the location of a possible mass grave.Produced with the support of the Bureau of Conflict and Stabilization Operations, United States Department of State
Robust and Fair Distributed Learning
Get PDFDistributed learning plays an important role in solving large-scale machine learning problems. It refers to the paradigm where a number of working nodes collectively carry out the overall task of training a model, typically with the coordination of a central node. As the deployment of machine learning becomes prevalent in modern safety-critical fields where the cost of model failure is extremely high, it is crucial to equip the learning systems with some robust features, such that the risk of model failure is minimized. For distributed learning, a typical and intrinsic safety issue is Byzantine failure, where a portion of workers exhibit abnormal or even adversarial behavior in the training phase, invalidating the learning result. In addition, due to the distributional shifts between training data and test data, the trained model may exhibit poor out-of-sample performance. Although many works dedicate to addressing either Byzantine attacks or distributional shifts separately, few consider these two issues at the same time. In this thesis, we propose a new algorithm that equips distributed learning with robustness measures against both Byzantine attacks and distributional shifts. This algorithm is built on recent advances in distributionally robust optimization (DRO) as well as norm-based screening (NBS), a robust aggregation scheme. Theoretical guarantees on the convergence of the proposed algorithm are provided, and the experimental results demonstrate the effectiveness of our algorithm against both robustness issues. In the meantime, as ML algorithms are increasingly used to make decisions of social consequences, the demand of model fairness has been increasingly emphasized in the latest ML research. Although tremendous efforts have been made to make ML algorithms fair, not many works devote such endeavors to distributed learning, and even fewer works consider fairness and robustness simultaneously in the distributed setting. To this end, we propose a distributed learning framework termed “H-nobs” that achieves Byzantine robustness and a sense of fairness simultaneously. H-nobs adopts the NBS scheme to gain resilience against Byzantine failure while employing a decomposable fairness-promoting objective function to realize the parallel goal of fairness. In this work, thorough convergence analysis is done for H-nobs. Moreover, the inherent conflicts between fairness and robustness are examined through empirical exploration for the very first time. Finally, we consider the decentralized setting, a practical variant of distributed learning where the central server is absent and the workers are self-coordinated and only able to communicate with their one-hop neighbors. We extend the H-nobs framework to this setting and propose DH-nobs for robust and fair decentralized learning. Compared to H-nobs, DH-nobs exhibits clearer advantages over other benchmarks in the decentralized setting. Interestingly, we find that in contrast to the distributed setting, there appears to be no obvious conflicts between robustness and fairness in decentralized learning, an observation worth further investigation
The Political Economy of Utopia and Dystopia
Get PDFThis dissertation seeks to use the lens of political economy to investigate notions of utopia and dystopia. The first chapter examines the failures of utopian projects, from small actions centered around individuals, to nationwide efforts to manage markets or societies. Despite promises from their advocates, utopian attempts fall victim to the same sort of knowledge and incentive problems and difficulties exporting institutions across cultures as other, less utopian, visions of economic development or nation-building. In fact, the very ambition of these efforts inspired their dystopian consequences leaving the participants worse off than had they never attempted the exercise at all. At the same time utopian visions serve useful purposes, so the chapter attempts to develop a positive theory of utopia grounded in reality but still capable of inspiring change. The second chapter examines the social criticism and social science of Karl Marx. The chapter contends that the success of the two projects is not linked - that valid social criticism has not resulted in successful predictive or prescriptive social science, but also that the failure of the latter does not necessarily invalidate the social criticism itself. The chapter shows that, in fact, much of the social criticism remains relevant and supported by a variety of contemporary voices in economic sociology, who collectively identify the threat of a dystopian future for individuals within a capitalist economy. The third chapter uses the 2020 COVID-19 pandemic as an example of a shock drawing on dystopian themes and fears. During the pandemic a variety of mitigation strategies were aggressively pursued which fell victim to the same challenges facing planners during past crises: knowledge problems regarding mitigation strategies, opportunities for corruption, etc. These mitigations were enacted in part because of the dystopian character of the early pandemic. Later mitigations would prove more effective at improving health outcomes, but paradoxically would see less use. The chapter argues that the lessons of past crises remain even more relevant during times of existential threat
EXPLORING CLASSROOM TEACHERS’ EXPERIENCES OF PD ABOUT EMERGENT BILINGUALS: AN INTERPRETATIVE PHENOMENOLOGICAL ANALYSIS
Get PDFThis study addresses the need for educators who are well-prepared to meet the needs of emergent bilinguals in the context of increasing cultural and linguistic diversity in U.S. schools. Using interpretative phenomenological analysis, this study explores the experiences of five classroom teachers in professional development (PD) related to emergent bilinguals. Six themes emerged through interviews with educators: including (a) PD promotes empathy, (b) PD as a catalyst for change, (c) importance of the PD context, (d) the content teachers want, (e) a community of practice, and (f) lack of pre-service preparation. These findings underscore the need for comprehensive and ongoing PD to better support teachers and students. School districts and policymakers must prioritize comprehensive, ongoing PD for educators to support emergent bilingual students effectively. Additional implications for teacher preparation programs, school leaders, policymakers, and future research are discussed
Ground-based Light Curve Follow-up Validation observations of TESS object of interest TOI 3945.01
Get PDF“The following paper covers the follow-up validation observations of the TESS Object of Interest (TOI) 3945.01 using images taken by the 0.8m telescope located on the George Mason University campus. The respective images of this TOI were then used to distinguish whether this candidate can be confirmed as an exoplanet or a false positive as part of the TESS Follow-up Observation Program (TFOP). The TESS mission, which aims to find and validate possible exoplanet contenders, has searched through over 200,000 stars near the sun and has found over 7,200 possible contenders as of June 26th, 2024 since its launch in April of 2018. Only 475 exoplanets have been confirmed out of these contenders. (Nowakowski, 2024). The goal of this research is to provide a ground-based follow up validation of the proposed exoplanet TOI 3945.01 and to confirm whether it is a transiting exoplanet of a false-positive, in this case most likely a nearby eclipsing binary (NEB). We carried out the research by using the application AstroImageJ to data reduce and plate-solve various darks, flats, and sciences taken by the George Mason University 0.8m telescope on the night of June 25, 2024. Following the plate-solving process, aperture and multi-aperture photometry allowed us to determine a light curve of our target. The following light curve provided us with more information about the planet including its p-value and other relevant statistics such as Research was carried out using the application AstroImageJ and a light curve was generated. Failed NEB checks and examinations of the outliers do not prove that there are no NEBs present, however NEB signals seemingly are not detected. Further work and research would have to be done to verify the presence of a planet, but the light curve is the first step forward in improving this research. If the planet were to exist, it would be classified as a hot Jovian planet due to its sub-10-day orbital period and radius (R_earth) of 9.59744.
Exploring the Design Process of an Online Teacher Professional Development for Korean Language Teachers to Adopt a Multiliteracies-Based Pedagogy in the K–12 Context: An Informed Exploration Phase of a Design-Based Research Study
Get PDFThis qualitative case study conducted under the informed exploration phase of design-based research explored the design process of an online teacher professional development (OTPD) prototype course for Korean language teachers to adopt a multiliteracies-based pedagogy in the K–12 context. This study is a response to the lack of research on professional development entailing the adoption of a multiliteracies-based pedagogy within the K–12 foreign language field that reflects the voices of practicing teachers. The first research question addressed how the designer’s experience and design principles were constructed in designing OTPD for Korean language teachers’ adoption of a multiliteracies pedagogy. The second research question examined how the participating Korean language teachers experienced and perceived a multiliteracies pedagogy approach during the design process of OTPD. The qualitative case study research analyzed qualitative data, which encompassed interviews with participating teachers, their participation in the sample activities and design document review, as well as the designer’s notes and design documents. The designer’s experience during the design process is summarized in six generated themes that affected the designer’s decisions from initial to revised design— considering students, making real-world connections, and acknowledging the boundaries of the curriculum and program—and from revised to final design—adapting to gradual change and the coexistence of pedagogies, developing a collaboration space for authentic texts for the new pedagogy, and demonstrating practical leading for modeling instructional languages and providing feedback. Subsequently, 12 design principles were generated to guide the design of OTPD, specifically for the adoption of a multiliteracies pedagogy. During the design process, the participating teachers displayed positive perceptions of authentic texts and a multiliteracies-based pedagogy. Nonetheless, they also indicated their need for mutual and practical advice concerning text searching, task scaffolding, and instructional examples and expressed concerns about aligning multiliteracies with their curriculum goals and students’ language proficiency. The study’s findings confirm the Community of Inquiry framework and provide additional design considerations, thus contributing to the existing knowledge base concerning online design aimed at developing teachers’ professional learning for the adoption of a multiliteracies pedagogy. The findings also clarify Korean teachers’ practical needs when adopting a multiliteracies pedagogy and identify areas for further research on a multiliteracies-based pedagogy for Korean language teaching
Filter Feeders in the Making: Examining the Evolution, Expansion, and Ecology of the Stem Mysticetes
No full textThis work is embargoed by the author and will not be publicly available until May 2029.While modern baleen whales are toothless and possess keratinous baleen pates which allow them to filter feed, the earliest members of this group possessed functional dentition, and fundamentally different ecologies than their descendants. The relationships and ecology of this group have been controversial in recent years, with back-and-forth studies supporting differing hypotheses of mysticete relationships and feeding ecology. This dissertation tests these disputed hypotheses of stem mysticete evolution and morphology. It conducts a phylogenetic analysis by creating a supermatrix from existing datasets, and coding data for relatively new taxa which were not previously included in analyses with those matrices. The resulting phylogenetic trees form the framework for a paleobiogeographic analysis which informs the oceanographic regions where stem mysticete clades originated. Elliptic Fourier Analysis of heterodont cetacean cheek teeth provided the first quantitative method of differentiating isolated archaeocete, odontocete, and mysticete teeth from the latest Eocene and the Oligocene. Finally, this dissertation assesses a recent scientific controversy in the evolution of baleen. The longstanding hypothesis that lateral palatal foramina with sulci in stem mysticetes are indicative of baleen is directly tested. A large dataset of palatal foraminal observations in extant mysticetes and odontocetes falsifies this hypothesis with the report of unambiguous lateral palatal foramina in extant toothed whales.2029-05-1
The Influence of Political Action Committee Contributions and Public Demand on U.S. Congressional Roll-Call Votes for a Pro-Environmental Policy
Get PDFPrevious studies have underscored the substantial impact of Political Action Committee (PAC) contributions on congressional policymaking, yet it remains unclear how political contributions might affect Senate voting behavior regarding environmental policies. Additionally, the extent to which political contributions may outweigh or complement the role of public opinion in shaping U.S. Senate votes remains unclear. To address this gap, this study collected data on PAC donations, public sentiment, and Senate votes on a selected pro-environmental bill. The results reveal a declining trend in PAC contributions over the past decade. Additionally, no correlation was found between PAC contributions and Senate votes, while issue salience showed a significant positive effect. This research elucidates the complex dynamics between political contributions, public demand, and legislative behavior, offering valuable insights for policymakers and stakeholders in the field of environmental policy
Transit Depth Variations of Young Warm Neptune AU Mic b
Get PDFWe present a study of transit depth variations of AU Mic b. The 33 transit observations used in this study were made by nine telescopes and were previously used to investigate the transit timing variations of the AU Mic planetary system. We modeled the light curves with EXOFASTv2, allowing for independent constraints on planetary parameters and allowed for each transit to have an independent transit depth. We then constructed a broadband transmission spectrum. Then, we modeled AU Mic b’s atmospheric spectrum using NASA’s Planetary Spectrum Generator (PSG). AU Mic b’s 7-4 spin orbit resonance with its host star allowed us to probe transit depth at one of four possible stellar longitude ranges per transit number. At 0.7865 microns, as observed by TESS, AU Mic b has an average Rp/R⋆ of 0.05048+0.00073−0.00088, while at 4.5 microns, as observed by Spitzer, AU Mic b has an average Rp/R⋆ of 0.04552+0.00092−0.00097. Our model atmospheres, with an average Rp/R⋆ of 0.05111 at 4.5 microns, indicate AU Mic b should be larger if unaffected by noise or stellar activity. Our investigation of transit depth per stellar longitude range shows no obvious effect of spot modulation. Given these results, and the previous studies on the young warm Neptune K2-33b, that resulted in the rejection of starspots and photochemical hazes, we conclude circumplanetary material is likely to exist around AU Mic b. If AU Mic b has circumplanetary material, this would present the opportunity to study it at an early age and close distance. This would be useful because circumplanetary material is challenging to observe