A multi-tasking operating system for microcomputers

Powell, Roger Farrington University of Arizona 1986 국내박사

Which way do I go? Strategic representations in rat prefrontal cortex on spatial decision tasks

Powell, Nathaniel James University of Minnesota 2015 해외박사(DDOD)

The role of the Prefrontal Cortex (PFC) in animal behavior is both complex and subtle. This dissertation concerns the role of rat PFC on spatial decision-making tasks, particularly how it represents strategies or rules necessary to solve these tasks. First I review the current state of knowledge about the role of the rat PFC in regard to behavior and decision-making (Chapter 1). Then I describe the spatial decision-making tasks and electrophysiological recording techniques I used to explore the role of PFC in rats (Chapter 2). Using one of these tasks, I found overlapping populations of PFC neurons that simultaneously encoded multiple relevant task parameters, including some cases in which multiple parameters were encoded by single neurons (Chapter 3). I also describe the spatial firing properties of PFC neurons on these tasks and conclude that although these cells do not seem to directly represent space per se, there are important differences in both single-cell and population representations that corresponded to the animal's location on spatial tasks (Chapter 4). Finally, using a population decoding approach that takes advantage of the spatially coded information in the cells, I identify transitions between different strategic representations in the PFC of animals performing these tasks. In general the transition between states occurred after animals received information that caused them to change their strategy but before the actual change in their behavior. Additionally, these transitions cannot be accounted for solely on the basis of changes to either sensory information or motor output, which proves that these transitions between strategic representational states are cognitive processes (Chapter 5).

Dynamics of Large-Scale Convective Onset in the Madden-Julian Oscillation

Powell, Scott Wayne University of Washington 2016 해외박사(DDOD)

The role of large-scale circulation anomalies in the convective onset of the Madden-Julian Oscillation (MJO) over the Indian Ocean during the Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign, conducted Oct. 2011--Feb. 2012, is explained using radar and rawinsonde observations, reanalysis, and regional model simulations. Convective onset was characterized by two episodic and rapid increases in the vertical growth of the cumuliform cloud population over the Indian Ocean: First, the areal coverage of moderately deep (~5 km) convection increased; about 1 week later, the areal coverage of deep (up to the tropopause) convection increased rapidly. Deep tropospheric wavenumber 1 anomalies in zonal wind and vertical velocity circumnavigated the tropics repeatedly during DYNAMO. MJO convective onset occurred when the upward branch of this wavenumber 1 circulation arrived over the Indian Ocean because a reduction in large-scale subsidence cooled the troposphere and steepened the lapse rate below 500 hPa. This made the environment more conducive to development of moderately deep convection. The moderately deep convection moistened the environment during week-long transition periods by transporting moisture vertically from the boundary layer to the free troposphere and detraining it into the clear-air environment, particularly between 650--850 mb. Regional cloud-permitting model simulations of convection during MJO onsets reproduced the distinct transition periods. The modeling results confirmed that rapid cooling of the environment enhanced the areal coverage of, and thus total vertical transport of water within, moderately deep convection at the beginning of transition periods. Evaporation of cloud condensate via entrainment or dissipation of clouds was directly responsible for environmental moistening. Cooling of the climatologically stable layer between 700--850 mb was particularly important because it allowed a greater number of cumulus elements growing out of the boundary layer to completely penetrate the 700--850 mb stable layer and grow upward to the next stable layer near 500 mb. The results are descriptive of MJO convective events observed during DYNAMO, but not necessarily all MJO events. As such, they should not be generalized as the single operative method for MJO convective onset.

Expectation and Evaluation in Moral and Non-Moral Contexts

Powell, Derek ProQuest Dissertations & Theses University of Cali 2016 해외박사(DDOD)

People's evaluations of events often depend on their expectations about those events. There is often disappointment when events fail to meet expectations---sometimes even when the events are still positive overall---and there is a special thrill to having one's expectations exceeded. In this dissertation I propose a theory of event evaluation based on contrasts between global representations of states of the world that accounts for the role of expectations in evaluations. I then present four studies showing evidence for this model in moral and non-moral domains. In Study 1, I generated quantitative predictions from the model to fit existing data describing people's emotional reactions to risky monetary gambles. Study 2 is a naturalistic study examining football fans' reactions after wins and losses based on their Twitter activity. Fans' reactions are influenced by their prior expectations of winning or losing each game. The evaluation of events is intimately linked to the evaluation of actions, in that one mode for evaluating action is simply to evaluate the events brought about by those actions. Consequently, Studies 3 and 4 shift focus to judgments of moral actions. In Study 3, participants were asked to contrast pairs of identical actions taken against victims in different circumstances. Participants' expectations about victims' prior risk affected their moral judgments of the actions so that a victim's greater prior risk mitigated the severity of their moral judgments. Study 4 examined a naturalistic dataset of global Twitter activity in response to terrorism events. Terrorism events evoked larger public reactions when those events were surprising, with weaker reactions resulting when terrorism occurred in countries that suffer from high rates of terrorism. Finally, I discuss the implications of these findings for the normative status of human moral judgments. I discuss how expectations may play a role in the omission-commission distinction, moral luck, and victim blaming. Although it seems justifiable that expectations influence evaluations of non-moral events, in judgments of moral actions this tendency may lead to pervasive moral error.

Teachers and professional reading: A study of reading experience and administrative support across traditional, Paideia, and PDS schools

Powell, Michelle Pettijohn Baylor University 2006 해외박사(DDOD)

The present study explored the perceived level of support teachers experience while pursuing professional reading as part of professional development. In order to do so, a descriptive study was designed to investigate the professional reading of teachers working in nine public schools located in Texas, Tennessee, and North Carolina during the Spring of 2005. There teachers participating in this study worked at elementary, middle, and high schools, as well as at Paideia, professional development schools (PDSs), and non-PDS schools. The Teacher Survey of Professional Reading (TSPR) was created specifically for this study, and is a 38 question instrument designed to gather information regarding reading as part of personal and professional growth, reading as part of professional growth, support for professional reading, reading as part of professional development, and demographic information. Teachers, in general, view professional reading as helping them grow in their profession. While teachers do not have enough time to read as they would like, they find the materials easily understood, applicable, and accessible. In addition, teachers working on Paideia campuses have strong beliefs regarding the use of professional reading as part of staff development, as they were more likely to find that professional reading helps them grow in their profession, and were more likely to find the materials applicable, relevant, and worthwhile to what they teach as compared to teachers working on PDS and non-PDS campuses. A discussion of the findings of practical significance and suggestions for future research are included.

"You Don't Just Stay in One Place": The Intergenerational Pedagogy of Two African American Families in the South

Powell, Jessica S The University of North Carolina at Chapel Hill 2013 해외박사(DDOD)

This postcritical ethnography shares the intergenerational stories of the Jordan and Cooper families, two African American families living in Parrish City, a medium sized city in the southeastern United States. In this study I explore the Cooper and Jordan family narratives across three generations to understand the varied histories of schooling, education, segregation, and desegregation that are embodied in the stories they share. While the experiences of the Cooper and Jordan families are unique, they also reflect patterns of race and family-school dynamics evident in our culture and society. Their stories describe an intergenerational family pedagogy defined as the moves, choices, and messages shared across generations to support the educational and social mobility of their children and grandchildren. This pedagogy enabled the families to navigate de jure and de facto segregated communities in hopes for a better future for themselves , their children, and the generations to follow. The family stories not only counter deficit portrayals of the segregated Black communities of the past, but also provide a critique of contemporary schooling. Through thematic interpretations and the conceptual framework of Community Cultural Wealth (Yosso,2005), I argue that the family narratives illustrate a strong cultural capital evident though an intergenerational family pedagogy, which has persisted through generations.

Perspectives on firm decision making during risky technology acquisitions

Powell, Adam C University of Pennsylvania 2011 해외박사(DDOD)

A novel survey dataset on computed tomography (CT) machine acquisition is used to explore which theories best answer two questions from the decision making literature. First, what determines how much uncertainty a firm has when investing in updated technology? Second, what determines the value of the acquisition? In answering these questions, two theoretical comparisons are conducted. In the first, economic theory, behavioral theory (the Behavioral Theory of the Firm and Prospect Theory), and Bounded Rationality are tested as potential determinants of acquisition uncertainties. In the second, economic theory and Prospect Theory are tested as potential determinants of the value of the machine acquired. To answer these questions, hospitals were surveyed about the acquisition of their most valuable computed tomography machine. From the survey data, support was found for the Bounded Rationality hypothesis; firms have less uncertainty about an acquisition's performance on attributes that correspond to more strongly held objectives. Support was also found for the behavioral theory hypothesis; firms whose prior machines perform below aspiration levels seek more uncertainty in their subsequent acquisitions, while firms whose machines perform above aspiration levels seek less uncertainty. No support was found for the normative hypothesis; acquisition uncertainty is determined by economic attributes. In the second comparison, partial support was found for the normative theory hypothesis and no support was found for Prospect Theory hypothesis. The value of the acquisition increased as the minimum lifespan of the acquisition increased. Perceived revenue, operating cost, and financial factor uncertainty did not significantly influence acquisition value, providing no support for Prospect Theory. However, greater uncertainty over the acquisition's ability to fulfill customer desires was associated with the acquisition of a less expensive machine. Studies of the influence of uncertainty on capital investment decision making have traditionally focused on financial forms of uncertainty. The results of this study suggest that the influence of uncertainty related to an acquisition's ability to fulfill customer desires may have an even stronger influence on the value of an acquisition than variables related to the non-perceptual characteristics of the acquirer.

Creating an Osage Future: Art, Resistance, and Self-representation

Powell, Jami C ProQuest Dissertations & Theses The University of 2018 해외박사(DDOD)

Creating an Osage Future: Art, Resistance, and Self-Representation , examines the ways Osage citizens---and particularly artists---engage with mainstream audiences in museums and other spaces in order to negotiate, manipulate, subvert, and somet. In addition to object-centered ethnographic research with contemporary Osage artists and Osage citizens and collections-based museum research at various museums, this dissertation is informed by three recent exhibitions featuring the work of Osa.

The Financial Management Practices of Small, Private, Non-Profit Colleges

Powell, James R University of Virginia 2011 해외박사(DDOD)

Small, private, non-profit colleges in the United States are generally highly tuition dependent for the majority of their revenue. As a result, the financial management practices of these types of institutions are critical to their survival. The recent economic downturn has affected the financial condition of all institutions of higher education, but especially small private colleges. The purpose of this study was to explore the financial management practices of these types of colleges that contributed to their financial difficulties and to discover what strategies these institutions are utilizing to ameliorate these financial circumstances. A qualitative approach was employed. Seven institutions, from three different regional accreditation areas, agreed to participate in the study. Data collection included interviews with senior level administrators at each of the participating institutions in addition to an analysis of available financial data for these colleges. Five themes concerning financial management practices emerged and included the following: 1) that communication of financial data with the college governing board and other key personnel has to be a priority, 2) the importance of enrollment management activities to effective financial management, 3) that fundraising has to be enhanced and focused to find donors who will support the college's mission, 4) that college officials should know their debt status and the potential drain this could be on the budget, and 5) the importance of measuring financial management success. Recommendations for successful financial management of these types of higher education institutions, derived from the experiences of the participating colleges, are provided.

The uncertainty principle in harmonic analysis and Bourgain's theorem

Powell, Alexander M University of Maryland College Park 2003 해외박사(DDOD)

We investigate the uncertainty principle in harmonic analysis and how it constrains the uniform localization properties of orthonormal bases. Our main result generalizes a theorem of Bourgain to construct orthonormal bases which are uniformly well-localized in time and frequency with respect to certain generalized variances. In a related result, we calculate generalized variances of orthonormalized Gabor systems. We also answer some interesting cases of a question of H. S. Shapiro on the distribution of time and frequency means and variances for orthonormal bases.