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Beyond Classical Statistics: Optimality in Transfer Learning and Distributed Learning
No full textDuring modern statistical learning practice, statisticians are dealing with increasingly huge, complicated and structured data sets. New opportunities can be found during the learning process with better structured data sets as well as powerful data analytic resources. Also, there are more and more challenges we need to address when dealing with large data sets, due to limitation of computation, communication resources or privacy concerns. Under decision-theoretical framework, statistical optimality should be reconsidered with new type of data or new constraints. Under the framework of minimax theory, this thesis aims to address the following four problems: 1. The first part of this thesis aims to develop an optimality theory for transfer learning for nonparametric classification. An near optimal adaptive classifier is also established. 2. In the second part, we study distributed Gaussian mean estimation with known variance under communication constraints. The exact distributed minimax rate of con- vergence is derived under three different communication protocols. 3. In the third part, we study distributed Gaussian mean estimation with unknown variance under communication constraints. The results show that the amount of additional communication cost depends on the type of underlying communication protocol. 4. In the fourth part, we investigate the minimax optimality and communication cost of adaptation for distributed nonparametric function estimation under communication constraints
The Hard-to-Measure Aspects of Firms
No full textThis dissertation explores the aspects of firms that are hard-to-measure, hard-to-observe, and hard-to-quantify. Chapter 1 investigates amenities of work that go beyond a wage. Using matched employee-employer data for the United States, this chapter estimates the joint distribution of wages, amenities, and job satisfaction across firms. There are three main findings. First, high-paying firms are high-satisfaction firms because they offer better amenities. Second, workers, especially high-earners, are willing to pay for job satisfaction, gaining in amenity value at least 50 percent of the average wage when moving from the worst- to the best-amenity firms. Third, since the elasticity of total compensation inclusive of amenity value to wages across firms exceeds one, incorporating non-wage amenities raises total compensation variance across firms by at least 52 percent. Chapter 2 investigates firm reputation. Using workers\u27 volunteered reviews on the platform Glassdoor, we find that the content most valuable to jobseekers (negative information) is the kind most risky to supply, pointing to a Catch-22. Higher ratings increase labor supply to less well-known firms, creating an incentive for smaller firms to discourage negative reviews. Concerns about employer retaliation discourage negative reviews and motivate employees who do disclose to conceal aspects of their identity, degrading the information’s value. Reputation institutions provide valuable but partial solutions to workers\u27 information problems. Chapter 3 investigates firm culture. Using a sample of corporate scandals and data from the website Glassdoor, we study how negative reputation shocks affect the relationship between firms and their employees. Worker sentiment declines sharply and persistently following scandals, driven by diminished perceptions of management and culture. While base earnings and fringe benefits remain unchanged, variable compensation falls 10 percent. Our results demonstrate that rank-and-file employees are adversely impacted by corporate misconduct
Improvements in Interferometric Data Modeling for the New Era of Radio Cosmology
No full textThe redshifted 21 cm line promises to provide a wealth of information about the evolution of our universe but remains as yet undetected. The general theme of this thesis is developing increasingly realistic models of the raw data we collect from a radio telescope. This is important because at the end of the day extracting the cosmological signal from the data will be accomplished by achieving a level of understanding of all the possible alternative sources that might mimic the cosmological signal, to a degree that we can confidently reject those alternatives as causes of our detection. The work presented in this thesis has been done in the context of working on the HERA experiment which aims to make the first measurements of spatial fluctuations in the emission from neutral hydrogen. In this thesis I emphasized aspects of the visibility function that are important for efficient and realistic visibility simulations including full account of polarization effects, in particular using a harmonic parameterization of the integrand. I assessed the effect of potential ionospheric attenuation on the suppression of polarization contamination in 21 cm power spectrum measurements using visibility simulations based on historical ionospheric plasma density data. I showed how we can use closed-form calculations of the cross-frequency angular power spectrum on the sky to generate simple mock cosmological signal simulations that are useful for validating data analysis methods. I showed how the window functions associated with a 21 cm power spectrum estimate can be approximated by simple forms that are much cheaper to evaluate than the general definition. Finally, I produced a new Southern Sky Model that combines the best available diffuse radio emission surveys that cover HERA\u27s field of view and observing bandwidth with a point source catalog without double counting flux
Penn Library\u27s Ms. Codex 1664 - [Compendium alchimiae]. (Video Orientation)
No full texthttps://repository.upenn.edu/sims_video/1145/thumbnail.jp
Collation Model for Ms. Codex 1156: Epithome artis epistolaris ... [etc.] [manuscript].
Get PDFEpithome artis epistolaris, the predominant work, is a treatise on rhetoric and letter writing based on authors and sources ranging from classical antiquity to the Renaissance. Rhegius draws strongly on Cicero, Quintilian, and Poliziano, but also references Aristotle, Plutarch, Pliny the Younger, Ovid, Juvenal, Terence, Vergil, Horace, Lucretius, Caesar, Livy, Augustine, passages from Psalms and Exodus, Albertus Magnus, Erasmus, Giorgio Valla, Ermolau Barbaro, Heinrich Bebel, Franciscus Niger, and Ulrich Zasius; many of these references are noted in the margins. The treatise explores the classical tenets of rhetoric, including inventio, dispositio, exordium, and elocutio; marginal annotations also make reference in Greek to various tools of rhetoric, including metaphor and periphrasis. Although the authorship of Epithome artis epistolaris was originally uncertain, it has been attributed to Urbanus Rhegius early in his career (Rhegius\u27 name appears multiple times throughout the manuscript in both Hebrew and Roman letters: see f. 6r-v, 8v, 9r, 16v). The predominant work is preceded by an excerpt from a medieval comedic poem, several pages of which have been removed, and several brief writings concerning rhetoric and philosophy.https://repository.upenn.edu/sims_models/1043/thumbnail.jp
Collation Model for Ms. Codex 1263: Confessione generale [manuscript].
Get PDFA two-part manual of confession for use by a female penitent, probably in a religious order. The first part gives the form for the penitent to confess, structured in a customary way around the ten commandments, the seven mortal sins, the five senses, the twelve articles of faith, the three theological virtues, the four cardinal virtues, and the seven spiritual gifts. The text uses feminine endings and forms, and includes the penitent\u27s confessions of sin, written in the first person and sometimes referring to wrongdoing against her sisters. The second part is a manual to guide priests through the sacrament of confession, again structured around the ten commandments, the seven mortal sins, the five senses, and the theological and cardinal virtues. References to Saint Augustine in both parts (f. 1r, 9v, 29v) may suggest that the context of this manuscript was a religious community under the Rule of Saint Augustine.https://repository.upenn.edu/sims_models/1045/thumbnail.jp
Natural Gas Conversion into Clean Hydrogen and Carbon for Li-ion Battery Electrodes Using Renewable Energy
Get PDFThe global green hydrogen market, set to increase 54% by 2030, was valued at 1.83 billion USD in 2021 (Precedence Research, 2022). Making use of the recent availability and affordability of solar energy as well as the high demand for green hydrogen, major strides have been made in the decarbonization of the commodity chemicals industry. Traditionally energy intensive processes, such as steam methane reforming (SMR) for the production of hydrogen and natural gas fired furnaces (NGFF) for the production of carbon black, can be replaced with alternative renewable electricity powered processes. This project proposes one such process in which solar energy is used to power the conversion of methane from renewable natural gas (RNG) into green hydrogen and acetylene black. The microwave conversion of renewable natural gas reduces water consumption by 86.7% and carbon dioxide emissions by 99.9% compared to SMR. Compared to NGFF, this process reduces water consumption by 99.5% and carbon dioxide emissions by 99.8%. Leveraging low carbon fuel standards in Southern California, the plant will produce 10 TPD of hydrogen sold at a premium. The plant was found to have an ROI of 113%, IRR of 86%, and a NPV of 20,625,800 USD
Penn Library\u27s LJS 408 - [Sharḥ al-Mulakhkhaṣ fī al-hayʼah]. (Video Orientation)
No full texthttps://repository.upenn.edu/sims_video/1161/thumbnail.jp
Be the Change: How Living With Virtue Contributes to the Collective Good
Get PDFThe vast majority of humans yearn for a better world. Underlying that desire is a hope that others will be better. We want politicians to act with integrity; social media CEOs to prioritize our mental health; energy executives to care for our planet; romantic partners to understand our needs; children to spend less time online. In short, we want people to live more virtuously. But how do go about achieving this? I believe Gandhi’s teachings provide the answer. He taught that we need not wait for others to change, instead, we can be the change that we are seeking. Gandhi believed humans are interconnected and that when one person changes, the collective also changes. To some, this might sound far-fetched, but scientific research is emerging that demystifies this wisdom. This paper underscores the benefits to the collective when individuals live with virtue. It begins with a review of Gandhi’s life, then highlights research related to sustainable behavior change, and culminates with an amalgamation of research that demonstrates behavior contagion from individuals to the collective. As we strive to create a better world for future generations, we\u27d be smart to be the change that we are seeking
Psychedelics, Positive Psychology, and Positive Humanities
Get PDFPublic and scientific interest in the effect of psychedelic drugs on wellbeing has risen significantly. Preliminary data show that psychedelic drugs, specifically classic psychedelics (DMT, psilocybin, mescaline, and LSD), may have the potential to treat mood disorders and increase wellbeing through their acute subjective effects. The acute subjective effects and enduring effects of psychedelics on wellbeing seem to relate to positive psychological frameworks (e.g., resilience factors and PERMA) considerably. Moreover, optimizing acute subjective effects indicates the importance of set (individual’s internal (mental) factors) and setting (individual’s external factors) in psychedelics administration as moderating factors. A new subfield in positive psychology, positive humanities, has the potential to inform set and setting studies significantly. This literature review investigates the potential for positive psychology and positive humanities in enhancing psychedelic studies, specifically the research areas of acute subjective effects and set and setting. Due to the seeming alignment between the operation of psychedelic drugs and both positive psychology and the positive humanities, there appear to be opportunities for research and scholarship at the intersection of these fields