Theses and Dissertations from UMD
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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.
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Item A DATA-INFORMED MODEL OF PERFORMANCE SHAPING FACTORS FOR USE IN HUMAN RELIABILITY ANALYSIS(2009) Groth, Katrina M.; Mosleh, Ali; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Many Human Reliability Analysis (HRA) models use Performance Shaping Factors (PSFs) to incorporate human elements into system safety analysis and to calculate the Human Error Probability (HEP). Current HRA methods rely on different sets of PSFs that range from a few to over 50 PSFs, with varying degrees of interdependency among the PSFs. This interdependency is observed in almost every set of PSFs, yet few HRA methods offer a way to account for dependency among PSFs. The methods that do address interdependencies generally do so by varying different multipliers in linear or log-linear formulas. These relationships could be more accurately represented in a causal model of PSF interdependencies. This dissertation introduces a methodology to produce a Bayesian Belief Network (BBN) of interactions among PSFs. The dissertation also presents a set of fundamental guidelines for the creation of a PSF set, a hierarchy of PSFs developed specifically for causal modeling, and a set of models developed using currently available data. The models, methodology, and PSF set were developed using nuclear power plant data available from two sources: information collected by the University of Maryland for the Information-Decision-Action model [1] and data from the Human Events Repository and Analysis (HERA) database [2] , currently under development by the United States Nuclear Regulatory Commission. Creation of the methodology, the PSF hierarchy, and the models was an iterative process that incorporated information from available data, current HRA methods, and expert workshops. The fundamental guidelines are the result of insights gathered during the process of developing the methodology; these guidelines were applied to the final PSF hierarchy. The PSF hierarchy reduces overlap among the PSFs so that patterns of dependency observed in the data can be attribute to PSF interdependencies instead of overlapping definitions. It includes multiple levels of generic PSFs that can be expanded or collapsed for different applications. The model development methodology employs correlation and factor analysis to systematically collapse the PSF hierarchy and form the model structure. Factor analysis is also used to identify Error Contexts (ECs) – specific PSF combinations that together produce an increased probability of human error (versus the net effect of the PSFs acting alone). Three models were created to demonstrate how the methodology can be used provide different types of data-informed insights. By employing Bayes' Theorem, the resulting model can be used to replace linear calculations for HEPs used in Probabilistic Risk Assessment. When additional data becomes available, the methodology can be used to produce updated causal models to further refine HEP values.Item An Investigation of Exclamatives in English and Japanese: Syntax and Sentence Processing(2006-08-24) Ono, Hajime; Lasnik, Howard; Linguistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation is a case study of the syntax of the left periphery, using exclamatives in English and Japanese. In the first part, I discuss exclamatives in Japanese in detail by focusing on the properties of the exclamative wh-phrases and particles that function as licensors for wh-phrases in exclamatives. We argue that licensing exclamatives involves at least three functional heads: Finite, Focus, and Mood. Especially, the necessity of the Mood head differentiates exclamatives from interrogatives. On the other hand, we claim that having these three functional projections does not type the clause as exclamative, and show that the presence of a wh-phrase of a distinct form is in fact a crucial part of the clause-typing for exclamation. This conclusion supports the claim that clause type should not be directly encoded into syntax as an independent functional category. The second part of dissertation deals with English exclamatives. We show that sluicing is available in English exclamatives, suggesting that focus is playing a role for the availability of sluicing, assuming that both interrogatives and exclamatives involve focus. Another conclusion about English exclamatives is that exclamative wh-clauses are licensed, not by selection, but by being c-commanded by a factive operator or a factive predicate. This goes against the traditional observation; our conclusion is empirically justified based on the observation that it is possible to license exclamative wh-clauses by a non-local licensor. We argue that this property is similar to what has been observed for the aggressively non-D-linked wh-phrases, accounting for the distribution and behavior of those non-standard wh-phrases. Finally, we investigate how Japanese exclamatives are processed by native speakers of Japanese with an on-line self-paced reading study and two off-line sentence fragment completion studies on the processing of wh-exclamative sentences in Japanese. These studies investigate the real-time formation of sentential structures with higher functional categories, and show that the parser immediately engages to build syntactic structures with discourse-oriented higher functional projections before coming across the head, favoring the incremental processing model.