VictorJuiz/thesis huggingface dataset:
Localized Structures in Forced Oscillatory Systems

This dissertation studies nonlinear partial differential equations (PDEs) describing pattern formation, using a combination of analytical and numerical techniques. A major part focuses on spatially localized states in/nthe 1:1 forced complex Ginzburg-Landau equation/n(FCGLE)/n\begin{equation*}/nA_t=(\mu +i\nu)A-(1+i\beta )|A|^{2}A +(1+i\alpha )\nabla^2A+\gamma, \quad A=U+iV\in\mathbb{C}, \quad U,V\in\mathbb{R},/n\end{equation*}/nwhich is the normal form for a 1:1 resonantly forced Hopf bifurcation in spatially extended systems./nOne-dimensional (1D) steady localized states can be fruitfully studied using tools from dynamical systems theory./n%The steady-state ordinary differential equation (ODE) is treated as a dynamical system in the space variable using numerical continuation techniques, and time evolutions of these steady solutions are performed using direct numerical simulation for PDEs./nIn particular, the localized states consisting of a Turing pattern embedded in a background equilibrium are shown to grow along its bifurcation curve via a new mechanism called defect-mediated snaking (DMS). In this growth mechanism new rolls are nucleated from the center of the wavetrain, in contrast to standard homoclinic snaking observed in the generalized Swift-Hohenberg equation. The temporal dynamics of localized states outside the snaking region are mediated by successive phase slips resulting from the Eckhaus instability. The spatial dynamics of DMS are explained by an asymptotic theory near a saddle-center bifurcation in a planar reversible map./nAside from DMS, a new class of steady localized states consisting of phase-winding states, namely spatially periodic states with $U$ and $V$ out of phase, are shown to grow via collapsed snaking mediated by a central pacemaker defect rather than standard homoclinic snaking. Parameter regimes exhibiting localized spatiotemporal chaos (STC) are also identified, and weak STC is interpreted in terms of its underlying coherent structures./nTwo-dimensional (2D) spatially localized states that exist in the same parameter regimes as their 1D counterparts include localized ring patterns, planar and circular localized hexagons, as well as 2D localized STC. These solutions are studied in detail using numerical continuation and direct numerical simulations./nThe final chapter derives a nonlocal pattern equation for weakly nonlinear Rayleigh-B\'enard convection with large aspect ratio using the Bogoliubov method coupled with a diagrammatic technique. A Lyapunov functional for the nonlocal pattern equation is found and a necessary condition for finding stable localized states in variational PDEs is formulated.

Advisor: Knobloch, Edgar
Moral Hazard, Adverse Selection, and Mortgage Markets

This dissertation considers problems of adverse selection and moral hazard in secondary mortgage markets. Chapters 2 and 3 consider moral hazard and adverse selection respectively. While Chapter 4 investigates the predictions of the model presented in Chapter 2 using data from the commercial mortgage backed securities market./nChapter 2 derives the optimal design of mortgage backed securities (MBS) in a dynamic setting with moral hazard. A mortgage underwriter with limited liability can engage in costly eﬀort to screen for low risk borrowers and can sell loans to a secondary market. Secondary market investors cannot observe the eﬀort of the mortgage underwriter, but they can make their payments to the underwriter conditional on the mortgage defaults. The optimal contract between the underwriter and the investors involves a single payment to the underwriter after a waiting period. Unlike static models that focus on underwriter retention as a means of providing incentives, the model shows that the timing of payments to the underwriter is the key incentive mechanism. Moreover, the maturity of the optimal contract can be short even though the mortgages are long-lived. The model also gives a new reason for mortgage pooling: selling pooled mortgages is more eﬃcient than selling mortgages individually because pooling allows investors to learn about underwriter eﬀort more quickly, an information enhancement eﬀect. The model also allows an evaluation of standard contracts and shows that the "ﬁrst loss piece" is a very close approximation to the optimal contract./nChapter 3 considers a repeated security issuance game with reputation concerns. Each period, an issuer can choose to securitize an asset and publicly report its quality. However, potential investors cannot directly observe the quality of the asset and a lemons problem ensues. The issuer can credibly signal the asset's quality by retaining a portion of the asset. Incomplete information about issuer type induces reputation concerns which provide credibility to the issuer's report of asset quality. A mixed strategy equilibrium obtains with the following 3 properties: (i) the issuer misreports asset quality at least part of the time, (ii) perceived asset quality is a U-shaped function of the issuer's reputation, and (iii) the issuer retains less of the asset when she has a higher reputation./nChapter 4 documents empirical evidence that subordination levels for commercial mortgage backed securities (CMBS) depend on issuer reputation in a manner consistent with the model of Chapter 3. Speciﬁcally, issuer retention is negatively correlated with issuer reputation. New measures for both issuer reputation and retention are considered.

Advisor: Wallace, Nancy E
Tchistyi, Alexei
Corporate Default Prediction

In the literature of predicting corporate default, it is an ad-hoc process to select the predictors and different models often use different predictors. We study the predictors of U.S corporate default by Forward Stepwise and Lasso model selection methods. Out of 30 candidate default predictors that have been used in the default-predicting literature, we identify a set of eight default predictors that have strong effects in predicting default using the U.S corporate default data from 1984-2009. We compare the eight default predictors' predicting effect over the past three major economic recessions and find that the recession in early 1990 and the recent sub-prime mortgage crisis share some common default characteristics, while the recession in 2000 is different from the other two. We then present a decision-based default prediction framework where we incorporate the default forecaster's loss utility into default classification and derive an optimal decision rule for this classification problem. By combining the default forecaster's loss utility into Support Vector Machines(SVMs), we show that minimizing the utility adjusted hinge loss is consistent with minimizing utility adjusted classification loss. Our empirical classification result of the decision-based Support Vector Machines demonstrates more classification accuracy and flexibilities in meeting different default forecasters' goals in comparison to traditional statistical methods.

Advisor: Guo, Xin
Global Affinities: Portuguese Marranos (Anusim), Traveling Jews, and Cultural Logics of Kinship

This dissertation explores issues of identification, relatedness, and belonging on a global scale, through an ethnographic study of Portugal's urban Marranos (descendants of fifteenth-century forced converts to Catholicism) and foreign Jews who travel from abroad to meet them. Although not Jewish according to Jewish law, given centuries of intermarriage, Marranos are nonetheless widely considered to be part of "the Jewish family," "lost brethren" who should be welcomed back to the Jewish people. Many Jews view them within the metanarrative of Jewish destruction and survival, the "eternal spark" that remains despite the Inquisition's attempted elimination of Judaism from the Portuguese landscape. However, for numerous local reasons the present-day Marranos are not welcomed by Portugal's tiny normative Jewish community. As a result, the urban Marranos, who feel strongly that they are Jews by descent, turn to foreign Jewish travelers as sources of educational, spiritual, and material assistance in their bid to join the Jewish world and attain recognition as Jews in the present./nBased on two years of fieldwork in Marrano organizations in Lisbon and Porto and traveling alongside Jewish tourists and outreach workers, the dissertation undertakes a processual analysis of the constitution of ancestral Jewish identity and of the role of transnational, cross-cultural affective ties in affording a sense of global Jewish belonging. The primary questions driving this work are, first, how and why do far-flung people come to feel that they are related to one another, and what terms do they use to characterize and think through that feeling of relatedness? Second, to what extent are their perceptions of essential connection disrupted or transformed by face-to-face contact? By interrogating the cultural logics of kinship writ large--the language and conceptual frameworks people use to articulate and make sense of their feelings of relatedness to one another--and then examining how those logics play out "on the ground," this study provides a fine-grained ethnographic analysis of the mechanisms through which global and ancestral imaginings become concretized in social interaction. Ultimately, I argue, physical proximity remains the productive sphere for identification and belonging, even as global interconnection provides new opportunities for encounter.

Advisor: Graburn, Nelson H.H.
Money and Mad Ambition: Economies of Russian Literature 1830-1850

This dissertation offers a sustained examination of the economic paradigms that structure meaning and narrative in Russian literature of the 1830s-1840s, the formative years of nineteenth-century Russian prose. Exploring works by Alexander Pushkin, Nikolai Gogol, Fyodor Dostoevsky, and Faddei Bulgarin, I view tropes such as spending, counterfeiting, hoarding, and gambling, as well as plots of mad or blocked ambition, in relation to the cultural and economic history of Nicholas I's reign and in the context of the importation of economic discourse and literary conventions from abroad. Furthermore, I consider the impact of culturally and economically conditioned affects--ambition, avarice, and embarrassment--on narrative tone. From the post-Revolutionary French plot of social ambition to the classic character type of the miser, the western economic models Russian writers routinely invoked seemed strangely out of place in Russia's autocratic and serf-based society. At a historical moment when the question of Russian specificity was frequently posed with reference to Europe, and the modern European discourses of aesthetics, the emotions, and political economy were solidifying in opposition to one another, Russian writers made prolific and paradoxical use of economic paradigms to explore the role of literature and the nature of feeling in a society in which the state, rather than the bourgeoisie, was the primary motor of history. Incorporating the perspectives of New Economic Criticism as well as the history of emotions, Money and Mad Ambition strives to account for the interrelationship between Russian literature and economics in the second quarter of the nineteenth century.

Advisor: Ram, Harsha
Do Online Game Players Overplay?

The amount of time youth spend on game-playing is significant, with a recent representative survey pinning the number at 0.84 hours per day. To investigate the extent to which gameplaying can be attributed to self-control problems, I first present a model of leisure consumption, followed by implementing two field experiments to test the implications of the model./nThe model has four predictions. First, players who are aware of their time-inconsistency play weakly shorter and weakly fewer sessions. Second, only players aware of their time-inconsistency would use a commitment device. Third, when commitment is available, sophisticated players play weakly shorter but weakly more sessions. Fourth, the model predicts that only cue-sensitive players would use multiple commitment devices during the same game session./nIn the first experiment, I monitored the amount of time 105 undergraduates spent playing online games for a period of 3.5 months. Students assigned to the treatment group were additionally given software that they could use to limit their duration of play. I found that the demand for commitment appears limited---while 79 percent of the treatment subjects used the software voluntarily in the first four weeks, the fraction eventually dropped to around 5 percent. At the end of the experiment, 10.4 percent of treatment subjects had a positive willingness-to-pay for the software. There is suggestive evidence that usage of the commitment device reduces duration of play but not frequency of play---subjects in the treatment group played an estimated 66.4 percent less than those in the control group, as measured by total hours played. The difference is driven by a reduction among heavy players, and persists even after most subjects stopped using the devices. Lastly, I find that players on average overestimated how long they would play./nIn the second experiment, I find that 12-35 percent of subjects provided with a commitment device manifested a demand for it, depending on what threshold one uses to categorize a subject as having a demand. The availability of commitment device reduces the number of long sessions while increasing that of short sessions. Lastly, players with commitment devices stay longer with the game.

Advisor: DellaVigna, Stefano
Room to Read: Tracking the Evolution of a New Secondary School Library

Room to Read: Tracking the Evolution of a New Secondary School Library/nby/nMarjorie Cummings Goodin/nDoctor of Philosophy in Education/nUniversity of California, Berkeley/nProfessor P. David Pearson, Chair/nThe purpose of this study was to examine and describe the evolution of a new school library, one that was a site for learning and practicing literacy in collaborative ways. By tracking the construction of school library resources and programs at a secondary school where no library existed, I was able to explore the processes and elements of library formation as it impacts the literacy environment. My hunch was that by improving the available resources in a distributed library, the opportunities for access and choice, and by developing the library dispositions of the students there might be observable changes in students' reading attitudes, engagement and achievement at the school. These library dispositions include developing habits of mind and attitudes that guide student thinking and intellectual behaviors, and that may be measured through actions taken to access library resources and to read independently./nIn this study I viewed the school library project as an intervention--one that sought to develop a culture of reading and information use with adolescents--by attending to access, choice, motivation and engagement in reading, and by collaborating with amenable content area teachers on instructional supports. My initial research concerns included how library dispositions are taken up in a school, or not, as a distributed library was developed on site; what barriers and benefits of building library resources and instructional connections to students and content area curricula might be evident; and how increased access to resources might impact the attitudes about reading and reading achievement of a focal group of students. The design research approach allows an examination of the impact of the library as intervention (the product) as it is engineered and adapted with input from the school community (the process)./nThis dissertation argues that the school library exists in an academic Third Space animated by constant tensions: in the ideological space between traditional in-school instructional goals and out-of-school learning priorities, in the curricular space between explicit curricular requirements and independent learning desires, and in the physical space between facility competitions for access to group learning space versus individual learning space.

Advisor: Pearson, P. David
Quantum Jumps and Measurement Backaction in a Superconducting Qubit

Real-time monitoring of a quantum state provides powerful tools for studying the backaction of quantum measurement and performing quantum feedback. Historically, this monitoring capability has been the exclusive province of atomic and optical physics. This thesis describes the implementation of the first such high-fidelity readout scheme in a solid state circuit, a superconducting quantum bit (qubit) coupled to a microwave cavity in the circuit quantum electrodynamics (circuit QED) architecture. The qubit-state-dependent resonance frequency of the cavity is probed with a microwave drive tone, and the resulting signal amplified using a fast, ultralow-noise superconducting parametric amplifier. This arrangement enables the observation of quantum jumps between the qubit states in real time./nThe ability to monitor the qubit continuously with high fidelity and resolve quantum jumps can be used to investigate the backaction of the measurement process on the qubit. This thesis examines the quantum Zeno effect--where strong measurement inhibits the evolution of a quantum system-- as well as the transition to non-ideal measurement with increasing measurement strength in the circuit QED architecture, a phenomenon shown to be due to the upconversion of low-frequency dephasing noise. These data allow probes of ``universal'' flux noise in previously inaccessible frequency ranges. The work presented here opens the door for quantum feedback and error correction in solid-state quantum systems using continuous weak measurement.

Advisor: Siddiqi, Irfan
The Instrumental Model

The goal of this dissertation is to enable better predictive models by engaging raw experimental data through the Instrumental Model. The Instrumental Model captures the protocols and procedures of experimental data analysis. The approach is formalized by encoding the Instrumental Model in an XML record. Decoupling the raw experimental data from the data analysis procedure, the Instrumental Model provides means for rigorous uncertainty quantification of predictive model./nThe concept of the Instrumental Model and its data model, which governs how the data is described, is discussed in this work. The Instrumental Model XML record is linked to raw experimental data records and calibration data records, providing a complete description of the experimental data./nThe Instrumental Model approach is first demonstrated using a set of formaldehyde oxidation shock-tube experiments. In those experiments, the transmitted laser light intensity was measured by a photodiode and the produced voltages were recorded by a computer. The corresponding Instrumental Model transforms these raw data into CO concentration upon the user's request./nThe Instrumental Model is expanded by performing uncertainty quantification of model predictions using raw data from a more complex experiment - a stoichiometric C2H2/O2/Ar premixed laminar flame mapped with VUV-photoionization molecular-beam mass spectrometry. The experimental signals were modeled with a premixed laminar flame code augmented with an Instrumental Model, designed to link raw signals to derived properties. The consistency of the model and raw experimental data are quantified and predictions for weak-signal observations of O, OH, C2H3 and unknown background H2O mole fractions are made.

Advisor: Frenklach, Michael
Pluralizing Nationalism: Narrative, Politics and the Figure of the Revolutionary in the Hindi Novel from the 1930s to the 1950s

This dissertation investigates the figure of the revolutionary in the Hindi novel by establishing its lineage in the literary tradition of the Bengali novel from the eighteen eighties to the nineteen twenties, as well/nas its lineage in the historical world of the nineteen twenties in the/ndebate between Gandhi and the several revolutionaries who were hanged by colonial authorities. The usefulness of the Hindi novels of the nineteen thirties to the nineteen fifties is that they served as the primary site for an elaborated introspection of the aims and motivations of the revolutionaries. The novel-form yields a diversity of responses to the meaning of revolutionary action. Each of the three Hindi novelists/ndiscussed has a singular perspective. Jainendra uses the interruption of/nthe apathetic middle-class household by the revolutionary to probe the/nunexpected opening of political as well as sexual desire. Agyeya uses the/nimminence of punitive death by the colonial authorities as an occasion for/nan extended meditation on the entirety of the subjective forces that/nshaped the revolutionary's brief life. Yashpal uses the revolutionary/nfigure to demonstrate a variety of evolving political thought in the/ninterwar years, especially the relation of older forms of anti-colonialism/npredicated on the simple experience of injustice to the new, unabsorbed,/nmutating ideas of international socialism. All three novelists extended/nthe bare political ideal of anti-colonial revolution into new domains of/nheterosexual desire and modes of subjectivation, thus facilitating the/ncross-fertilization of the novelistic form between, on the one hand,/nconventional social realism and on the other hand, the many emergent and experimental modernist forms.

Advisor: Dalmia, Vasudha
Ultra-low field MRI of prostate cancer using SQUID detection

In this dissertation, I investigate various applications of prepolarized magnetic resonance imaging (MRI) at ultralow fields, typically at 132 µT, detected with a superconducting quantum interference device (SQUID). One of the major advantages of working at ultralow fields is enhanced longitudinal-relaxation-time (T1)-weighted contrast. I measure T1 of healthy and cancerous prostate tissue specimens--within a few hours of their surgical removal--from approximately 50 patients. The measurements involve a field-cycling imaging technique in which I prepolarize protons in fields up to 150 mT. After this field turns off, the image of each pair of samples is encoded using magnetic field gradients, and the proton nuclear magnetic resonance signal is measured using a SQUID inductively coupled to an untuned, second-derivative gradiometer. The observed T1 contrast is significantly greater than that at (say) 1.5 T, suggesting that one may be able to distinguish tumors from healthy tissue without a contrast agent: on average I find that T1 of 100% tumor is 66% that of 100% normal prostate tissue. To make this imaging system suitable for in vivo imaging of human prostates, I integrate a 200-A, 150-mT prepolarizing coil that will adequately polarize the human prostate. Assuming a prepolarizing field of 150 mT at the prostate, and a noise of 0.2 fT Hz-1/2, we can acquire a T1 weighted contrast image of the prostate with resolution 2×2×3 mm3 in 22 minutes with a contrast-to-noise ratio of 4. Measurements of preliminary standard phantoms designed by NIST in Boulder, CO for measuring T1, proton density, and resolution are discussed. I also present calculations for a method of tuning the input coil of the SQUID at low frequencies (~10 kHz) while adding minimal noise. This tuning would be useful to block very low frequency, high amplitude drifts of the ambient second-order gradient magnetic field while preserving the high balance of the gradiometer.

Advisor: Clarke, John