VictorJuiz/thesis huggingface dataset:
Dynamic optimization with random and smoothed constraints [electronic resource]

Stochastic control theory is a well known mathematical framework that is widely applied because of its robustness. This thesis describes the use of stochastic control, convex optimization, and time smoothing, for resource allocation in radio communication systems. As the demand for heterogeneous multimedia services increases, it has become increasingly important to devise more efficient resource allocation strategies. These resource allocation problems can be represented as network flow control problems where the goal is to design flow controllers, which are equivalent to network protocols. We present a stochastic control framework, that integrates adaptive modulation and network utility maximization, for designing simple and implementable adaptive flow rate controllers for efficient and fair resource allocation. For each problem presented, we characterize the exact optimal controller and in a few special cases we show how to compute it. For cases where computing the optimal controller is intractable, we design efficient suboptimal controllers using approximate dynamic programming.

Keywords: Electrical Engineering
Advisor: Boyd Stephen P. primary advisor. Thesis advisor
Gill John T.
O'Neill Daniel
The dynamics of effusive volcanic eruptions [electronic resource] : kinematic and physics-based inversions of observations at Mount St. Helens, 2004-2011

Despite advances in the technology used to monitor volcanoes, our understanding of volcanic systems remains quite rudimentary, in part due to limitations in the techniques typically used to infer properties of magmatic systems from observations recorded at the surface. The kinematic models typically used with geodetic observations have no predictive ability, cannot easily be used to model multiple data sets, and generally cannot be used to infer anything about the actual magmatic processes which give rise to modeled changes in pressures and volumes. The 2004-2008 eruption of Mount St. Helens resulted in a wealth of remarkable data which can be used to better understand key magmatic processes, and also suggests a clear opportunity to move beyond some of the limitations associated with traditional modeling techniques. This work focuses firstly on characterizing and modeling enigmatic cyclic ground tilt events with the goal of gaining insight into critical upper-conduit processes at Mount St. Helens; results are consistent with a mechanism involving extrusion of the semi-solid dacite plug and/or cycles of conduit pressurization. The second part of this work focuses on the development of a physics-based model of an effusive silicic volcanic eruption which is coupled to the host rock and therefore can be used to relate magma physics with diverse surface observations. The third part of this work involves the development of a technique for using a physics-based model of an effusive volcanic eruption in a Bayesian inversion, constrained by diverse data sets and independent information, to estimate key properties of a magmatic system including the volume, pressure, depth, and volatile content of the magma chamber, and properties of the fluid conduit and solid plug. Finally, this technique is applied to the 2004-2008 eruption of Mount St. Helens and is used with observations of ground deformation and lava dome extrusion from that eruption to estimate properties of the magmatic system.

Keywords: Geophysics
Advisor: Segall Paul
Dunham Eric advisor. Thesis advisor
Mahood Gail A.
The dynamics of partisanship within election cycles [electronic resource]

Is party identification immovable and immune from short-term influences or is it swayed by political dynamics that arise during campaigns and elections? Social scientists have debate the answer to this question for over fifty years while relying on data that measures partisanship between elections. This dissertation incorporates data from two unique sources to offer a look into how partisanship behaves within election cycles. First, I observe individual-level systematic changes in partisanship over the course of the 2008 presidential election campaign using 10-wave panel data covering the 13 months leading up to the election. Partisanship becomes entangled by and confused with vote intention. Furthermore, these changes cannot be accounted for by measurement error alone. Next, I use the same data set to evaluate the relative stability of partisanship compared to a diverse set of attitudes and find it as stable, but not more stable, than ideology or evaluations of president's job performance. Finally, by bringing together an aggregate set of data composed of over 160 high quality commercial and academic public opinion polls, I am able to corroborate the patterns found in 2008. Overall, partisan intensity decreases closer to elections and increases further away from the glare and mixed messages of a campaign. Implications for how we understand American politics are discussed.

Keywords: Sociology.
Advisor: Parigi Paolo
Sandefur Rebecca
Nie Norman H. advisor. Thesis advisor
Ecological and evolutionary connections between genetic and species diversity [electronic resource]

Understanding the causes and consequences of biological diversity remains the unifying goal of ecology and evolutionary. One promising avenue to understand the causes and consequences of genetic diversity within populations is to consider correlations between that genetic diversity and species diversity of the community in which it resides. Both genetic and species diversity can respond to locality characteristics, or each level can influence and be influenced by the other. First, I investigate how area connectivity and gene flow affects the population genetic diversity patterns in the California vole (Microtus californicus). I show that migration across the landscape produces an identical genetic patterns at the local and regional spatial scales in this small mammal (Chapter 1). Next, I explored two ways in which genetic and species diversity influence each other. In one approach, I examine the effects of a species-rich competitor community on the genotypic diversity of a focal community when genetic diversity allows for differential strength of competition with different species. Using computer simulations, I show that species diversity of competitors can act as an important promoter of genotypic diversity within species (Chapter 2). Next, moving to a riparian community in northern Utah, I demonstrate that the genetic diversity of a foundation tree correlates positively with the species diversity of understory plants, including forbs, grasses, and vines (Chapter 3). Finally, I show that both genetic diversity and species richness across the globe show a similar pattern: genetic markers in over 70 vertebrate species show a significant trend of higher diversity at low latitudes than at higher latitudes (Chapter 4). By taking a broad approach to understanding the causes and consequences of intraspecific genetic diversity, with a particular focus on links to species diversity patterns, my dissertation finds general principles that operate across systems. The two levels of diversity can influence each other by creating spatially-varied selection regimes, but gene flow and mutation are two processes operating on the genetic level whose power to scale up to influence species-level patterns is highly contextual.

Keywords: Biology.
Advisor: Dirzo Rodolfo primary advisor. Thesis advisor
Boggs Carol L.
Hadly Elizabeth Anne
Vellend Mark
Ecological importance of large fishes [electronic resource]

In this dissertation I explore how ecosystems change when their largest faunal residents are removed. Specifically I consider how coral reef ecosystems respond to the removal or depletion of a variety of functionally and taxonomically unique large reef fish. There are seven chapters in this thesis. Chapter 1 critically examines the performance of four methods for estimating coastal shark abundance. I compare outputs from field survey trials conducted at Palmyra to results from computer simulations to evaluate the efficacy of these selected methods. In Chapter 2 I present the results of an experiment conducted at our near-pristine reef site where I excluded large fish and tracked the effects of their absence. I observed that the removal of these larger ecosystem constituents affected a variety of responses including algal growth, fish behavior, and invertebrate recruitment. These changes occurred rapidly and were observed to interact in complex ways with one another. Chapter 3 relies on the use of stable isotopes to identify how large fish build linkages across ecosystems. I use isotopes of C and N and mixing models to determine what energy sources large reef predators rely upon and to infer how these utilization patterns influence ecosystem connectivity and functioning. In Chapter 4 I examine some provocative observations made in unfished and fished reefs which suggest that large fish predators control the temporal niche structure of their prey. I observed that the removal of day-time active predators from fished reefs appears to have caused an increase in the abundance of nocturnal prey fishes. Chapter 5 is an investigation of the functional ecology of the world largest parrotfish B. muricatum. Using this animal as a model, I consider how ecologically dominant animals affect the functioning of ecosystems. Conclusions are drawn from intensive field observation and simulation exercises. Chapter 6 utilizes a diversity of research approaches (biogeochemical tools, ecological surveys, animal tracking) to chronicle a long ecological interaction chain that links forests to manta rays. By contrasting processes in disturbed and undisturbed study sites I consider how anthropogenic disturbance more generally affects the length of ecological interaction chains. Finally, in chapter 7 I discuss the importance of protecting remote ecosystems that often harbor intact communities of large animals. I argue that extremely remote environments are critically important and yet vulnerable repositories of biodiversity and I review how existing conservation strategies may be adapted to help protect these special environments.

Keywords: Biology
Advisor: Micheli Fiorenza primary advisor. Thesis advisor
Dirzo Rodolfo advisor. Thesis advisor
Dunbar Robert advisor. Thesis advisor
Estes J. A. (James A.)
Palumbi Stephen R. advisor. Thesis advisor
Ecological studies on seed dispersal networks [electronic resource] : insights from a diverse tropical ecosystem

Mutualisms between animals and plants, such as pollination, seed dispersal and ant-plant protection, are key ecological processes in many ecosystems throughout the world. Like any other ecological interaction, plant-animal mutualisms occur in a community context. Therefore, one-to-one interactions are very rare in nature and the majority of species, both animals and plants, have more than one partner. Recently, studies on mutualistic interactions at the community level have used the "network approach" in order to simplify complex interactions and to determine both the pattern of interaction and the properties of species in networks. In this dissertation, I use network theory combined with long-term field work, phylogenetic and multivariate analysis, species extinctions simulations and experimental manipulation to identify the pattern of interaction in a seed dispersal network, to assess the contribution of particular animal species to network stability and robustness, and to address the extent to which seed dispersal interactions can structure plant communities. To do so, I studied a hyper-diverse seed dispersal network sampled in the Brazilian Pantanal, which includes interactions among plant species from 28 families and seed dispersers, both native and exotic species, from 25 families and 4 taxonomic groups. This study contributes novel information on seed dispersal at the community level, especially because I examined a diverse and relatively complete seed dispersal network, which may provide insights for other diverse systems, especially in the tropics. Besides generating information on the ecology and evolution of plant-animal interactions, this study also shows that not all seed disperser species are equal at the community level; and body size of dispersers seem to be a useful proxy of relative importance for dispersal services. Since contemporary defaunation differentially affects species depending on body size, this work illustrates how human activities, such as hunting, land use and climate change, affect not only taxa, but also crucial processes in which animals of different body size play different roles. This study emphasizes that conservation science needs to look at the conservation of ecological processes driven by species interactions.

Keywords: Biology.
Advisor: Dirzo Rodolfo primary advisor. Thesis advisor
Boggs Carol L.
Micheli Fiorenza advisor. Thesis advisor
The effect of grain boundaries on scintillation in rare-earth doped transparent ceramics [electronic resource]

The need for large-scale, low-cost, novel materials for the active component in nuclear detector systems has sparked an interest in optically transparent ceramic scintillators as an alternative to single crystals. Ceramics may be produced in large sizes and to near net shapes, using standard methods of ceramic forming and sintering. Additionally, bulk slabs of certain materials compositions that may not be accessible by single-crystal growth may be produced as ceramics. Although ceramic scintillators have been used in commercial CT scanners for some time now, in other applications, they have not reached the levels of performance that single-crystal scintillators have. Research into the properties of ceramic scintillators has been restricted to a small number of materials, processed under a limited number of conditions. Many studies on ceramic scintillators point to possible "defects at the boundaries" as a source of degraded scintillator performance and an origin of deep trapping, but the true effect of grain boundary defect states on scintillator performance has not been well-characterized. Additionally, the unique processing methods required to produce not only dense, but transparent ceramics had only been used on a handful of materials prior to 15 years ago, and limited work has been done on materials with non-cubic crystal structures. In order to address these two limitations, this dissertation focuses on the sintering and scintillation properties of ceramics of three model materials, Eu:Y2O3, Ce:Y3Al5O12 (Ce:YAG) and Eu:SrI2. Transparent ceramics of these materials were sintered, including non-cubic Eu:SrI2 for the first time by inducing grain texture in ceramics of the material. Eu:SrI2 ceramics were found to have as proportional a response as single crystals and a light yield of 25% of single crystals and 55% of Tl:NaI. Through parametric studies of ceramic processing parameters, grain size, and bulk scintillation, the effect of grain boundaries on scintillator performance was compared to that from other sources of charge carrier trapping and light yield degradation. Using models for charge carrier generation and transport in a ceramic and a new micro-scintillation technique, X-ray radioluminescence microscopy, the localized effect of grain boundaries on scintillation was also characterized. Based on these micro-scale studies, a greater understanding of the effect of grain boundaries on bulk scintillation was developed. Based on the conclusions of these sintering and scintillation studies, a number of criteria are suggested for identifying new and existing scintillator materials that may be of interest for further investigation as ceramics, because of their potential to maintain high levels of scintillator performance and optical transparency when fabricated in ceramic form.

Keywords: Materials Science and Engineering
Advisor: Cui Yi
Feigelson Robert S.
McIntyre Paul Cameron advisor. Thesis advisor
The effects of college diversity experiences on student academic and democracy outcomes [electronic resource]

Institutions of higher education claim they prepare their students to be leaders and positive contributors to society. In pursuit of these aims, institutions promote opportunities for diversity experiences among schoolmates. The legality of these claims has been challenged in court, and social science research on the effects of diversity experiences has played a pivotal role in shaping court rulings. Mixed results in previous studies and important unexamined questions in this research area prompt this examination of college diversity experiences. Classroom-based experiences, participation in diversity events, and the informal interactions students have with racially/ethnically dissimilar schoolmates are the foci of the study. Their relationships with democracy and academic outcomes are examined, and investigative emphasis is placed on the racial/ethnic heterogeneity of friendship groups and the relative position of students as outliers or majority-group members in primarily racially/ethnically homogeneous friendship groups. In addition to analyses of the full sample of University of Michigan students, analyses are performed on students based on their primary racial/ethnic identification and their status as racial/ethnic outliers or majority-group members. The results suggest that the three types of college diversity experiences benefit students. They are orthogonal to student outcomes for Asian-Americans, but significant positive relationships are seen across the analyses of White and Underrepresented Minority student groups. Outliers appear to benefit from diversity experiences in fewer ways than majority-group members, but the results are equivocal due to a statistical power issue. Implications for the research community are discussed.

Keywords: Education.
Advisor: Antonio Anthony Lising
Carter Prudence L.
Gordon Leah advisor. Thesis advisor
Ramirez Francisco O. advisor. Thesis advisor
Effects of priming and work relationship on linguistic alignment in computer-mediated communication and human-computer interaction [electronic resource]

People engaged in a conversation tend to express themselves in similar ways by using comparable or identical words, phrases, sentence structures, accent, speech rate, etc. This process and end results are termed "linguistic alignment, " and have also been observed in both computer-mediated communication (CMC) and human-computer interaction (HCI). Many researchers have demonstrated that linguistic alignment can be easily induced through priming, while others focus on the social aspect of linguistic alignment. Moreover, previous research work on linguistic alignment mostly focused on conversation within dyads. In this dissertation, I report two experimental studies that, in the context of a triadic conference chat setting, investigated the co-presence of alignment as a result of priming and alignment attributable to difference in work relationship (cooperation vs. competition). Similarities and differences observed in the HCI and CMC conditions were also examined. Results show that priming is a strong predictor of alignment even when interlocutors do not directly communicate with each other, but work relationship between interlocutors and communication type (i.e., HCI vs. CMC) could also sway the degree of alignment. Additionally, the priming effect on certain stylistic dimensions (e.g., vocabulary complexity) lasted relatively longer than the effect on other features (e.g., capitalization). As a whole, the dissertation proposes a holistic way of examining and understanding linguistic alignment, and offers researchers a new methodology utilizing realistic user contexts and tasks to study human language behaviors in general and those specific to HCI and CMC.

Keywords: Communication
Advisor: Nass Clifford Ivar primary advisor. Thesis advisor
Bailenson Jeremy advisor. Thesis advisor
Jurafsky Dan
Reeves Byron
Efficiencies of slowness [electronic resource] : the politics of contemporary collective creation

This project focuses on the process and performance of three contemporary collective creation groups: Goat Island, Elevator Repair Service, and Nature Theater of Oklahoma. I draw processual and aesthetic connections between collective creation methodologies and the consequences of those methodologies in performance, claiming that processes leave footprints that are ultimately visible to audiences, though their visibility requires new ways of seeing. Taking into account an American genealogy of collective creation, I outline the footprints of method through the images of everyday employment, instances of untrained bodies enacting danced gesture, and the speeds and velocities that characterize the work of these three contemporary groups. Through these aesthetics we can locate evidence of methodological principles that constitute a politics. In the work of Goat Island, Elevator Repair Service, and Nature Theater of Oklahoma, this politics does not play out through the ideological content of performance, but is embedded within collaborative acts of making.

Keywords: Drama
Advisor: Jakovljević Branislav primary advisor. Thesis advisor
Elam Harry Justin advisor. Thesis advisor
Ross Janice advisor. Thesis advisor
Efficient access to bryostatin and functional bryostatin analogs [electronic resource] : design, synthesis and evaluation of potent bryostatin analogs and the total synthesis of bryostatin 9 using B-ring annulative macrocyclization strategies

The bryostatins are a family of structurally complex natural products isolated from the marine bryozoan Bugula neritina. Bryostatin 1 is currently being investigated for cancer, Alzheimer's and HIV/AIDS indications. Despite these remarkable activities, research on the bryostatins is hampered by their low natural abundance. Efficient access by total chemical synthesis has been in large part precluded by the bryostatins' structural complexity. This dissertation describes the design, synthesis, and preliminary biological evaluation of functional bryostatin analogs that possess biological activities comparable or superior to the natural product. These fully synthetic analogs were convergently assembled in a uniquely step-economical manner using novel macrocyclization strategies, including macroacetalization and Prins-driven macrocyclization approaches. Bryostatin analogs were identified that possess unique affinities (subnanomolar) and selectivities for protein kinase C (PKC). Synthetic bryostatin analogs also exhibit subnanomolar antileukemic activity in in vitro assays. The convergent total synthesis of bryostatin 9, a highly potent congener of the natural product family, is also described.

Keywords: Chemistry
Advisor: Wender Paul A. primary advisor. Thesis advisor
Chen James Kenneth advisor. Thesis advisor
Du Bois Justin advisor. Thesis advisor