VictorJuiz/thesis huggingface dataset:
More with Less: Prioritizing U.S. Navy global presence with reductions in defense spending
Keywords: Center for International Security and Cooperation
CISAC
United States Navy
budget
austerity
defense
scenario analysis
Thesis

After a decade of war, America’s defense budget is almost certain to see reductions over the next several years. The full impact of austerity on the Navy as the principle vehicle of U.S. power projection however must be approximated in the context of an evolving geopolitical landscape. Although the Navy is unrivaled in size, capability, and reach, the development of anti- access/ area denial (A2/AD) weapon systems by rising powers in two strategically critical theaters—the Persian Gulf and the Asia Pacific—represents a growing problem. Maritime power dynamics are changing: China’s naval ascendancy combined with its ambitions in the South China Sea risks sparking a naval arms race, while Iranian belligerence in the Gulf threatens the free flow of oil in an already volatile part of the world. If the Navy is to continuing advancing a strategy of global engagement, it must find a way to projecting power even in a constrained future resource environment.
How can the Navy continue to promote U.S. interests while operating on a reduced budget? Using scenario analysis under three different budget cases—status quo, sequestration, and a hypothetical compromise solution—this paper assesses the outlook for U.S. naval presence and power projection in the Persian Gulf and Asia Pacific over the remainder of the decade.
To preserve its global dominance and regional influence, the Navy must invest in developing counter A2/AD systems and continue to emphasize power projection. Rather than shrink from a forward deployed posture, the Navy must adopt a prioritized engagement strategy that allocates ships with region-specific capabilities against region-specific security concerns. By maintaining forward presence, and by focusing on its core-competency—power projection—even with fewer ships, the Navy can do more with less.
Motivating older Americans to walk [electronic resource] : an application of socioemotional selectivity theory
Keywords: Psychology.

Mounting evidence suggests that active lifestyles may help to maintain physical and cognitive independence in old age by preserving good health. Walking is among the most cost-effective and accessible means of exercise. However, older Americans fall far short of meeting the daily recommendations for walking. In my dissertation research, I examine the relevance of socioemotional selectivity theory to the promotion of healthy lifestyles among older adults. In four studies, I examine whether or not considering older adults' preferential attention to positive information may effectively enhance interventions aimed at promoting walking. In Study 1, I compared the effectiveness of positive, negative, and neutral messages to encourage walking (as measured with pedometers). Older adults who were informed about the benefits of walking walked more than those who were informed about the negative consequences of failing to walk, whereas younger adults were unaffected by framing valence. In Study 2, I examined within-person changes in walking in response to positively- or negatively-framed messages over a 28-day period. Once again, positively-framed messages more effectively promoted walking than negatively-framed messages in older adults, and the effect was sustained across the intervention period. Study 3 extended this research to a less affluent population of older adults living in neighborhoods with many obstacles for health behaviors. The effectiveness of positively- compared to negatively-framed messages varied by ethnicity and neighborhood walkability. In Study 4, I examined whether selective adherence to positively-framed health recommendations among older adults was associated with neural and cognitive processes. Brain regions implicated in motivation and memory tracked with the processing of emotionally-valenced compared to neutral information across participants. Older adults remembered positively-framed information about walking better than negatively-framed information. Brain activation and explicit memory were associated with walking. Together, these studies suggest that consideration of age-related changes in preferences for positive and negative information may inform the design of effective interventions to promote healthy lifestyles.
Multimode optical fiber-tip photonic crystal pressure sensors [electronic resource] : toward low-cost, high-precision optical sensing
Keywords: Electrical Engineering.

With advantages in electromagnetic interference immunity, compactness, and tolerance to harsh environments, optical fiber sensors are suitable for a wide variety of applications, especially in corrosive, explosive, and radiative environments. Multimode fiber systems are attractive for their cost savings over single-mode fiber systems, but they also come with challenges associated with the presence of multiple spatial modes in a fiber: modal noise and mode averaging. In the context of pressure sensing, we report on the benefits of designing multimode fiber Fabry-Pérot Interferometers using short optical cavities: the mitigation of mode-averaging-induced sensitivity loss and phase uncertainty, and the mitigation of modal noise, which we further addressed by filtering. In light of the performance-cost tradeoff with multimode sensing, we pursued high sensitivity devices to maximize the benefits of such a low-cost system. Using single-crystal silicon, a material prized for its excellent optical and mechanical properties, we fabricated static pressure diaphragms with photonic crystals on its surface for high broadband reflectance, and assembled them on metallized fiber tips in an extrinsic Fabry-Pérot Interferometer configuration to create highly sensitive pressure sensors that had optical sensitivities that were up to ten times that of a sensor made with bare fiber and a pure silica diaphragm.
Multi-objective optimization using hyper-dual numbers [electronic resource]
Keywords: Aeronautics and Astronautics.

High-fidelity analysis tools can provide accurate predictions of the performance of a design. However, these tools often have a higher computational cost when compared to lower-fidelity tools. This can greatly increase the computational expense of tasks that require many repeated calls to the analysis tool, such as numerical optimization methods or uncertainty quantification techniques. There are various strategies that can be employed to reduce the computational cost. One strategy is to make use of additional information, such as the gradient (first-derivative information) or Hessian (second-derivative information). Gradient-based optimization methods can converge faster and require fewer function evaluations than non-gradient based methods. Optimization methods that use the Hessian, or an approximation to the Hessian, can further improve the rate of convergence and may require even fewer function evaluations. Response surfaces created using a few evaluations of the high-fidelity tool can also be used as surrogates for the high-fidelity analysis to reduce the computational cost. More accurate response surfaces can be created, using fewer sample locations, by incorporating first-derivative information. Including second-derivative information may provide a further benefit, provided it can be computed accurately and efficiently. Generalized complex numbers can be used to compute effectively exact first derivatives, by reducing the truncation error to below machine precision. Higher-dimensional extensions of generalized complex numbers can produce effectively exact second (or higher) derivatives, provided they have the property that multiplication is commutative. This dissertation develops a new number of this type, called hyper-dual numbers, in order to produce exact second derivatives. The mathematics of hyper-dual numbers enable first- and second-derivative calculations that are free from both subtractive cancellation error and truncation error, and therefore exact. This dissertation develops the mathematical properties of hyper-dual numbers and discusses their implementation in several programming languages. The implementations allow hyper-dual numbers to be easily applied to codes of arbitrary complexity. This is demonstrated on a 3D, parallel, unstructured computational fluid dynamics code, and the resulting derivative calculations are validated against exact results. Hyper-dual numbers are then applied to a multi-objective optimization method and two response surface creation methods.
Multiple antenna transmitter design under power constraints [electronic resource]
Keywords: Electrical Engineering.

Multiple-antenna technique is one of the fundamental building blocks for modern wireless communication systems. The spatial degrees of freedom provided by multiple antennas when used with appropriate transmit coding and receive signal processing, offer several performance advantages including array gain, diversity gain and multiplexing gain. Most theoretical results in multiple-antenna theory assume a sum-power constraint for the transmit antennas. However, practical multiple-antenna transmitters are often subject to per-Power Amplifier (PA) constraint and sometimes also Effective Isotropic Radiated Power (EIRP) constraint. These constraints are motivated by bio-safety, interference reduction and lower cost. However, per-PA power constrained systems suffer from performance loss under imbalances in channel gains at the transmit antennas that often occur in the presence of fading. This thesis studies point-to-point and multi-point-to-point transmission under per-PA power and EIRP constraints, focusing on techniques to increase link performance and to reduce algorithmic complexity. The first part of this thesis studies the use of a Power Combining Network (PCN) to improve link performance under a per-PA power constraint. A PCN switches the outputs of PAs associated with antennas with poor channels to antennas with good channels. The PCN balances the higher coupling gain of the PA power with the loss of array gain or diversity gain. We also study PCN design when an additional EIRP constraint is imposed. We develop fast algorithms for determining the optimal PCN under both a per-PA power constraint alone or with an additional EIRP constraint. We demonstrate the effectiveness of PCN through performance analysis and numerical evaluation. The second part of this thesis is motivated by reducing computational complexity of transmit beamforming algorithms in multi-point-to-point, so called a Coordinated Multi-Point (CoMP), transmission. Algorithmic complexity is high in CoMP since calculating the joint optimal transmit beamformers typically involves an iterative computation of intermediate solutions across the multiple base stations. We present a low-complexity minimum-mean-squared-error beamforming algorithm for CoMP transmission under per-PA power constraint. We decompose the original beamforming problem at each base station into a series of simpler sub-problems. Solution of each sub-problem is derived in a closed-form, and convergence proof and complexity analysis are presented. We demonstrate significant saving in computational complexity without compromising performance which is confirmed by numerical evaluation.
Multivariate density estimation by Bayesian sequential partitioning and its applications [electronic resource]
Keywords: Statistics.

Consider a class of densities which are piecewise constant functions over partitions of the sample space defined by sequential coordinate partitioning. We introduce a prior distribution for a density in this function class and derive in closed form the marginal posterior distribution of the corresponding partition. A computationally efficient method, based on sequential importance sampling, is presented for the inference of the partition from this posterior distribution. Compared to traditional approaches such as the kernel method or the histogram, the Bayesian sequential partitioning (BSP) method proposed here is capable of providing much more accurate estimates when the sample space is of moderate to high dimension. We illustrate this by simulated as well as real data examples. The examples also demonstrate how BSP can be used to design new classification methods and data compression methods competitive with or even superior to the state of the art. For the data compression application, we use sequence data of format FASTQ from human chromosome 21 and validate the performance of our method on both lossless and lossy compression.
The musical reception of Torquato Tasso's Rime, 1571-1620 [electronic resource]
Keywords: Music.

Arguably the most prominent poet of late 16th-century Italy, Torquato Tasso (1544-1595) produced throughout his career more than 1,500 lyric poems, collectively known as Rime. About 180 of these poems, for the most part madrigali liberi, enjoyed a remarkable musical fortune in the late 16th and early 17th centuries. Indeed, between 1571 and 1620 they received about 500 polyphonic settings by composers of varied geographical provenance, ranging from central Europe to Sicily. In this dissertation I explore this vast poetic-musical repertoire, to which both literary scholars and musicologists have so far devoted limited attention. In so doing, I pursue two main research avenues: the first is to understand how these poems became musical hits; the second is to determine how composers set them to music, providing a snapshot of compositional personalities and schools. The dissertation is divided in two parts. Part I is titled "Selected Centers" and is composed of four chapters, each on a center where Tasso's lyric poems received a particularly large number of settings. The centers I examine are Ferrara, Mantua, Genoa, and Prague. In these chapters, I study how local literary trends and contacts with Tasso and his entourage influenced the production of Rime settings in each center. In addition, I analyze the musical settings, determining how they fit within local compositional styles. Part II is titled "Selected Poems" and is composed of three chapters that explore the musical reception of two specific poems, "Non è questa la mano" and "La bella pargoletta, " and of group of poems, the canzonettas. In these chapters I focus on the question of transmission, tracing where composers drew the texts from, and on stylistic analysis. The dissertation is accompanied by an appendix with an up-to-date list of the extant settings of Tasso's lyric poems.
My Little (Homo)Nationalist Pony: a Critique of Zoophilia
Keywords: queer theory
queer studies
zoophilia
neocolonialism
queer activism
ecofeminism
sexual identity
sexual violence
dehumanization of racialized sexualities
human-animal relationships
bestiality
non-human animal erotica
Stanford University Feminist Gender and Sexuality Studies
Thesis

This essay won the 2013 Stanford University's Michelle Zimbalist Rosaldo Prize for undergraduate work. It provides a theoretical framework on zoophilia and post-humanist thinking in relationship to racism and neo-colonialism.
The myth of school improvement [electronic resource] : more than a decade of reform in one school and what it suggests about the American school improvement project
Keywords: Education.

For more than a decade, state and federal accountability policies have operated on the assumption that the school organization may improve continuously over a period of time, whether by adopting the behaviors of effective schools or by implementing Comprehensive School Reform. This dissertation takes a critical look at the problem of school improvement by documenting what happened at a California K-8 school from its origins in 1992 through 2008. The featured case was established as a developmental, multiage program and for ten years participated as a leadership site in the Bay Area School Reform Collaborative (BASRC). Drawing on institutional and organizational theory, this study uses a longitudinal, process-sequencing approach to document what happened inside the school. Multiple instances of principal turnover, episodes of major teacher turnover and policy changes affected the school's identity, organizational boundaries, curriculum and instruction and routines and relationships. Over time the school was isomorphic with its environment, changing in response to changes in district, state and federal regulatory policies, with certain events having path-dependent consequences for the school's trajectory. Under state and federal accountability policies individual schools are held responsible for improvement; this case illustrates how these same policies shifted significant decisions and authority over curriculum and instruction to the district and state levels. School principals were instrumental in establishing a tone of trust by making and breaking decision-making agreements and structures, but these structures were increasingly symbolic in nature. This case thus suggests limits to ideals such as school leadership, data-driven decision-making and continuous improvement, and raises questions about the notion of school capacity. Given continuous churn in policies and people comprising a school, the concept of school improvement deserves revaluation. Additionally, the study contributes to theory about schools as loosely-coupled systems, suggesting that tighter administrative control over schools does not necessarily make the system more tightly coupled. Finally, I argue that school improvement has become institutionalized across the field, but churn in the policies and people that comprise a school may make the school organization a meaningless unit of change.
Nanometer tip-based ultrafast electron sources [electronic resource] : emission processes and direct pulse characterization techniques
Keywords: Physics.

Since the first half of the 20th century, metal tips ending in hemispheres with a radius of curvature of hundreds of nanometers or less have been used as stochastic field emission electron sources because the small radius of curvature allows the application of very strong electric fields to the tip apex. These tips are high brightness electron sources because they have very small virtual source sizes-typically smaller than the tip radius. In this work, field emission tips are operated as pulsed electron sources triggered by a femtosecond laser; thus, the temporal profile of the electron emission is determined by the laser pulse, but the source size is much smaller than the diffraction-limited laser focal spot. Furthermore, due to optical field enhancement at the tip apex, it is possible to get into the strong field regime, where electron emission happens on a time-scale shorter than the optical period. Possible applications of these sources include ultrafast x-ray tubes, improved ultrafast time-resolved electron microscopy and diffraction, injectors for laser accelerators, and quantum optics experiments with time-tagged electrons. The first part of this thesis presents a unified picture of the ultrafast laser-induced emission processes (photo-assisted field emission, multiphoton emission and strong field photoemission, thermally enhanced field emission) and experimental characterization of these processes. The second half describes two ongoing experiments that seek to directly characterize the electron pulses in time. The first is based on streaking the bias field of the tip, which maps the electron emission time onto electron kinetic energy. The second is a cross-correlator for electrons and photons, where an electron absorbs a photon in the near field created by scattering light from a nanostructure. These experiments will constitute not only the first direct measurement of the electron pulse duration in this system but will also point the way towards new techniques for manipulating ultrafast electron pulses with optical and microwave fields.
Nanophotonic computational design [electronic resource]
Keywords: Electrical Engineering.

In contrast to designing nanophotonic devices by tuning a handful of device parameters, we have developed a computational method which utilizes the full parameter space to design linear nanophotonic devices. We show that our method may indeed be capable of designing any linear nanophotonic device by demonstrating designed structures which are fully three-dimensional and multi-modal, exhibit novel functionality, have very compact footprints, exhibit high efficiency, and are manufacturable. In addition, we also demonstrate the ability to produce structures which are strongly robust to wavelength and temperature shift, as well as fabrication error. Critically, we show that our method does not require the user to be a nanophotonic expert or to perform any manual tuning. Instead, we are able to design devices solely based on the user's desired performance specification for the device.
Nanophotonics [electronic resource] : near-field light propagation and optical force
Keywords: Applied Physics.

Nanophotonics is the study of light at a nanometer to micrometer scale. In this thesis, I present my work on two sub-fields of nanophotonics: near-field light propagation and optical force. In the near-field limit, where the light's propagation distance is shorter than the wavelength of light, light propagation is not restricted by the macroscopic diffraction limit. As a result, field patterns with sub-wavelength feature size are allowed. I will show that it is possible to intuitively describe this system in wavevector space. I will also show that it is possible to enhance the field in this system by the use of an interface between a positive- and a negative-permittivity material. This field enhancement can be used to compensate the decay that is characteristic of near-field propagation in free-space. It also allows the system to be optimized for image-transfer purposes, where the goal is to have the image resembles the original input field. In optical force studies, the presence of light in optical systems can exert an electromagnetic force on an object. For example, two parallel waveguides with light propagating along them can experience a force that pushes or pulls the two waveguides. The force in this system allows us to design a non-volatile optical memory, which, unlike conventional optical memory, can maintain a state without the need of continuous input power. I will also study the force between a waveguide and a coupled resonator. I will show that there is a fundamental limit on the system, and show a more complicated setup where the limit is overcome. Finally, I study the existence of an optical equilibrium in the optical force in the waveguide-resonator system. I will show that optical equilibrium cannot be obtained in a single-resonance system and requires the interaction between two resonances.