Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
Browse
3 results
Search Results
Item Predicting Cancer Prognosis and Drug Response from the Tumor Microbiome(2021) Hermida, Leandro Cruz; Ruppin, Eytan; Patro, Robert; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Tumor gene expression is predictive of patient prognosis in some cancers. However, RNA-seq and whole genome sequencing data contain not only reads from host tumor and normal tissue, but also reads from the tumor microbiome, which can be used to infer the microbial abundances in each tumor. Here, we show that tumor microbial abundances, alone or in combination with tumor gene expression data, can predict cancer prognosis and drug response to some extent – microbial abundances are significantly less predictive of prognosis than gene expression, although remarkably, similarly as predictive of drug response, but in mostly different cancer-drug combinations. Thus, it appears possible to leverage existing sequencing technology, or develop new protocols, to obtain more non-redundant information about prognosis and drug response from RNA-seq and whole genome sequencing experiments than could be obtained from gene expression or mutation data alone.Item How Grammars Grow: Argument Structure and the Acquisition of Non-Basic Syntax(2019) Perkins, Laurel; Lidz, Jeffrey; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the acquisition of argument structure as a window into the role of development in grammar learning. The way that children represent the data for language acquisition depends on the grammatical knowledge they have at any given point in development. Children use their immature grammatical knowledge, together with other non-linguistic conceptual, pragmatic, and cognitive abilities, to parse and interpret their input. But until children have fully acquired the target grammar, these input representations will be incomplete and potentially inaccurate. Our learning theory must take into account how learning can operate over input representations that change over the course of development. What allows learners to acquire new knowledge from partial and noisy representations of their data, one step at a time, and still converge on the right grammar? The case study in this dissertation points towards one way to characterize the role of development in grammar acquisition by probing more deeply into the resources that learners bring to their learning task. I consider two types of resources. The first is representational: learners need resources for representing their input in useful ways, even early in development. In two behavioral studies, I ask what resources infants in their second year of life use to represent their input for argument structure acquisition. I show that English learners differentiate the grammatical and thematic relations of clause arguments, and that they recognize local argument relations before they recognize non-local predicate-argument dependencies. The second type of resource includes mechanisms for learning from input representations even when they are incomplete or inaccurate early in development. In two computational experiments, I investigate how learners could in principle use a combination of domain-specific linguistic knowledge and domain-general cognitive abilities in order to draw accurate inferences about verb argument structure from messy data, and to identify the forms that argument movement can take in their language. By investigating some of the earliest steps of syntax acquisition in infancy, this work aims to provide a fuller picture of what portion of the input is useful to an individual child at any single point in development, how the child perceives that portion of the input given her current grammatical knowledge, and what internal mechanisms enable the child to generalize beyond her input in inferring the grammar of her language. This work has implications not only for theories of language learning, but also for learning in general, by offering a new perspective on the use of data in the acquisition of knowledge.Item SUBJECTIVE INTEGRATION OF PROBABILISTIC INFORMATION FROM DESCRIPTION AND FROM EXPERIENCE(2009) Shlomi, Yaron; Wallsten, Thomas S.; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Subjective integration of probabilistic information obtained via description and experience underlies potentially consequential judgments and choices. However, little is known about the quality of the integration and the underlying processes. I contribute to filling this gap by investigating judgments informed by integrating probabilistic information from the two sources. Building on existing information integration frameworks (e.g., N. Anderson, 1971), I develop and subsequently test computational models that represent the integration process. Participants in three experiments estimated the percentage of red balls in a bag containing red and blue balls based on two samples drawn from the bag. They experienced one sample by observing a sequence of draws and received a description of the other sample in terms of summary statistics. Subjective integration was more sensitive to information obtained via experience than via description in a manner that depended on the extremity of the experienced sample relative to the described one. Experiment 1 showed that experience preceding description leads to integration that is less biased towards experience than the reverse presentation sequence. Following this result, Experiment 2 examined the effect of memory-retrieval demands on the quality of the integration. Specifically, we manipulated the presence or absence of description- and experience- based decision aids that eliminate the need to retrieve source-specific information. The results show that the experience aid increased the bias, while the description aid had no interpretable effect. Experiment 3 investigated the effect of the numerical format of the description (percentage vs. frequency). When description was provided in the frequency format, the judgments were unbiased and the leading model suggested that the two sources are psychologically equivalent. However, when the description was provided in the percentage format, the leading model implied a tradeoff between the two sources. Finally, participants in Experiment 3 also rated how much they trusted the source of the description. The participants' ratings were correlated with how they used the description and with the quality of their judgments. The findings have implications for interpreting the description-experience gap in risky choice, for information integration models, and for understanding the role of format on the use of information from external sources. In addition, the methods developed here can be applied broadly to study how people integrate information from different sources or in different formats.