Matching Items (43,913)
Description
In contemporary U.S. culture, dance is often confined to the young and the trained, isolated on stages and in dance studios, and viewed as entertainment that is disconnected from "real life." Socially engaged dance practices re-connect dance to society in meaningful ways. By connecting individuals to their own bodies, to each other, to ideas, and to social, civic, and educational institutions, socially engaged dance practices use movement, the body, and the tools of participatory art, which contributes to the development of a democratic society, while catalyzing social change, and building healthy communities.
ContributorsJohnson, Elizabeth (Author) / Fitzgerald, Mary (Thesis advisor) / Standley, Eileen (Committee member) / Marshall, Alison (Committee member) / Arizona State University (Publisher)
Created2013
Description
This study focuses on state estimation of nonlinear discrete time systems with constraints. Physical processes have inherent in them, constraints on inputs, outputs, states and disturbances. These constraints can provide additional information to the estimator in estimating states from the measured output. Recursive filters such as Kalman Filters or Extended Kalman Filters are commonly used in state estimation; however, they do not allow inclusion of constraints in their formulation. On the other hand, computational complexity of full information estimation (using all measurements) grows with iteration and becomes intractable. One way of formulating the recursive state estimation problem with constraints is the Moving Horizon Estimation (MHE) approximation. Estimates of states are calculated from the solution of a constrained optimization problem of fixed size. Detailed formulation of this strategy is studied and properties of this estimation algorithm are discussed in this work. The problem with the MHE formulation is solving an optimization problem in each iteration which is computationally intensive. State estimation with constraints can be formulated as Extended Kalman Filter (EKF) with a projection applied to estimates. The states are estimated from the measurements using standard Extended Kalman Filter (EKF) algorithm and the estimated states are projected on to a constrained set. Detailed formulation of this estimation strategy is studied and the properties associated with this algorithm are discussed. Both these state estimation strategies (MHE and EKF with projection) are tested with examples from the literature. The average estimation time and the sum of square estimation error are used to compare performance of these estimators. Results of the case studies are analyzed and trade-offs are discussed.
ContributorsJoshi, Rakesh (Author) / Tsakalis, Konstantinos (Thesis advisor) / Rodriguez, Armando (Committee member) / Si, Jennie (Committee member) / Arizona State University (Publisher)
Created2013
Description
The speech of non-native (L2) speakers of a language contains phonological rules that differentiate them from native speakers. These phonological rules characterize or distinguish accents in an L2. The Shibboleth program creates combinatorial rule-sets to describe the phonological pattern of these accents and classifies L2 speakers into their native language. The training and classification is done in Shibboleth by support vector machines using a Gaussian radial basis kernel. In one experiment run using Shibboleth, the program correctly identified the native language (L1) of a speaker of unknown origin 42% of the time when there were six possible L1s in which to classify the speaker. This rate is significantly better than the 17% chance classification rate. Chi-squared test (1, N=24) =10.800, p=.0010 In a second experiment, Shibboleth was not able to determine the native language family of a speaker of unknown origin at a rate better than chance (33-44%) when the L1 was not in the transcripts used for training the language family rule-set. Chi-squared test (1, N=18) =1.000, p=.3173 The 318 participants for both experiments were from the Speech Accent Archive (Weinberger, 2013), and ranged in age from 17 to 80 years old. Forty percent of the speakers were female and 60% were male. The factor that most influenced correct classification was higher age of onset for the L2. A higher number of years spent living in an English-speaking country did not have the expected positive effect on classification.
ContributorsFrost, Wende (Author) / Gelderen, Elly van (Thesis advisor) / Perzanowski, Dennis (Committee member) / Gee, Elisabeth (Committee member) / Arizona State University (Publisher)
Created2013
Description
With increasing demand for System on Chip (SoC) and System in Package (SiP) design in computer and communication technologies, integrated inductor which is an essential passive component has been widely used in numerous integrated circuits (ICs) such as in voltage regulators and RF circuits. In this work, soft ferromagnetic core material, amorphous Co-Zr-Ta-B, was incorporated into on-chip and in-package inductors in order to scale down inductors and improve inductors performance in both inductance density and quality factor. With two layers of 500 nm Co-Zr-Ta-B films a 3.5X increase in inductance and a 3.9X increase in quality factor over inductors without magnetic films were measured at frequencies as high as 1 GHz. By laminating technology, up to 9.1X increase in inductance and more than 5X increase in quality factor (Q) were obtained from stripline inductors incorporated with 50 nm by 10 laminated films with a peak Q at 300 MHz. It was also demonstrated that this peak Q can be pushed towards high frequency as far as 1GHz by a combination of patterning magnetic films into fine bars and laminations. The role of magnetic vias in magnetic flux and eddy current control was investigated by both simulation and experiment using different patterning techniques and by altering the magnetic via width. Finger-shaped magnetic vias were designed and integrated into on-chip RF inductors improving the frequency of peak quality factor from 400 MHz to 800 MHz without sacrificing inductance enhancement. Eddy current and magnetic flux density in different areas of magnetic vias were analyzed by HFSS 3D EM simulation. With optimized magnetic vias, high frequency response of up to 2 GHz was achieved. Furthermore, the effect of applied magnetic field on on-chip inductors was investigated for high power applications. It was observed that as applied magnetic field along the hard axis (HA) increases, inductance maintains similar value initially at low fields, but decreases at larger fields until the magnetic films become saturated. The high frequency quality factor showed an opposite trend which is correlated to the reduction of ferromagnetic resonant absorption in the magnetic film. In addition, experiments showed that this field-dependent inductance change varied with different patterned magnetic film structures, including bars/slots and fingers structures. Magnetic properties of Co-Zr-Ta-B films on standard organic package substrates including ABF and polyimide were also characterized. Effects of substrate roughness and stress were analyzed and simulated which provide strategies for integrating Co-Zr-Ta-B into package inductors and improving inductors performance. Stripline and spiral inductors with Co-Zr-Ta-B films were fabricated on both ABF and polyimide substrates. Maximum 90% inductance increase in hundreds MHz frequency range were achieved in stripline inductors which are suitable for power delivery applications. Spiral inductors with Co-Zr-Ta-B films showed 18% inductance increase with quality factor of 4 at frequency up to 3 GHz.
ContributorsWu, Hao (Author) / Yu, Hongbin (Thesis advisor) / Bakkaloglu, Bertan (Committee member) / Cao, Yu (Committee member) / Chickamenahalli, Shamala (Committee member) / Arizona State University (Publisher)
Created2013
Description
Recent legislation allowing educational agencies to use Response to Intervention (RTI) in determining whether a child has a specific learning disability, coupled with a focus on large-scale testing and accountability resulted in the increasing use of curriculum based measurement (CBM) as a tool for understanding students' progress towards state standards, particularly in reading through the use of oral reading fluency measures. Extensive evidence of oral reading fluency's predictability of reading comprehension exists, but little research on differential effects across racial, gender, and socioeconomic subgroups is available. This study investigated racial, gender, and socioeconomic bias in DIBELS Oral Reading Fluency (DIBELS ORF) probes predictive and concurrent relationship with MAP reading comprehension scores for African American and Caucasian students. Participants were 834 second through fifth grade students in a school district located in a southeastern US state. The dataset consisted of student fall and spring DIBELS ORF scores and spring MAP reading comprehension scores. Concurrent correlation results between spring DIBELS ORF and MAP reading comprehension scores were moderate to large and statistically significant across all grades and demographic groups; however, correlations between fall DIBELS ORF and MAP reading comprehension scores were generally weak. Stepwise multiple regression analyses were used to examine the best variable, or combination of variables, in predicting MAP reading comprehension scores. Models differed for each grade level; however, spring DIBELS ORF scores were always included, whether alone or in combination with demographic variables, in the best prediction model. Potthoff's procedure was used to simultaneously test for slope and intercept differences among regression equations to determine if DIBELS ORF scores from fall and spring differentially predicted MAP reading comprehension scores across demographic groups. Nine of 24 simultaneous contrasts demonstrated a significant effect; seven were related to race, one was related to gender, and one was related to socioeconomic status. Racial bias in predicting MAP reading comprehension performance from spring DIBELS ORF was found. Differential prediction among gender and SES groups was not consistent indicating little to no practical significance. Results are discussed in the context of practical implications of differential validity, both predictive and concurrent, and potential impact on disproportionality.
ContributorsAdkins, Jill (Author) / Caterino, Linda C. (Thesis advisor) / Atkinson, Robert (Committee member) / Nakagawa, Kathryn (Committee member) / Arizona State University (Publisher)
Created2013
Description
Silicon solar cells with heterojunction carrier collectors based on a-Si/c-Si heterojunction (SHJ) have a potential to overcome the limitations of the conventional diffused junction solar cells and become the next industry standard manufacturing technology of solar cells. A brand feature of SHJ technology is ultrapassivated surfaces with already demonstrated 750 mV open circuit voltages (Voc) and 24.7% efficiency on large area solar cell. Despite very good results achieved in research and development, large volume manufacturing of high efficiency SHJ cells remains a fundamental challenge. The main objectives of this work were to develop a SHJ solar cell fabrication flow using industry compatible tools and processes in a pilot production environment, study the interactions between the used fabrication steps, identify the minimum set of optimization parameters and characterization techniques needed to achieve 20% baseline efficiency, and analyze the losses of power in fabricated SHJ cells by numerical and analytical modeling. This manuscript presents a detailed description of a SHJ solar cell fabrication flow developed at ASU Solar Power Laboratory (SPL) which allows large area solar cells with >750 mV Voc. SHJ cells on 135 um thick 153 cm2 area wafers with 19.5% efficiency were fabricated. Passivation quality of (i)a-Si:H film, bulk conductivity of doped a-Si films, bulk conductivity of ITO, transmission of ITO and the thickness of all films were identified as the minimum set of optimization parameters necessary to set up a baseline high efficiency SHJ fabrication flow. The preparation of randomly textured wafers to minimize the concentration of surface impurities and to avoid epitaxial growth of a-Si films was found to be a key challenge in achieving a repeatable and uniform passivation. This work resolved this issue by using a multi-step cleaning process based on sequential oxidation in nitric/acetic acids, Piranha and RCA-b solutions. The developed process allowed state of the art surface passivation with perfect repeatability and negligible reflectance losses. Two additional studies demonstrated 750 mV local Voc on 50 micron thick SHJ solar cell and < 1 cm/s effective surface recombination velocity on n-type wafers passivated by a-Si/SiO2/SiNx stack.
ContributorsHerasimenka, Stanislau Yur'yevich (Author) / Honsberg, C. (Christiana B.) (Thesis advisor) / Bowden, Stuart G (Thesis advisor) / Tracy, Clarence (Committee member) / Vasileska, Dragica (Committee member) / Holman, Zachary (Committee member) / Sinton, Ron (Committee member) / Arizona State University (Publisher)
Created2013
Description
The digital forensics community has neglected email forensics as a process, despite the fact that email remains an important tool in the commission of crime. Current forensic practices focus mostly on that of disk forensics, while email forensics is left as an analysis task stemming from that practice. As there is no well-defined process to be used for email forensics the comprehensiveness, extensibility of tools, uniformity of evidence, usefulness in collaborative/distributed environments, and consistency of investigations are hindered. At present, there exists little support for discovering, acquiring, and representing web-based email, despite its widespread use. To remedy this, a systematic process which includes discovering, acquiring, and representing web-based email for email forensics which is integrated into the normal forensic analysis workflow, and which accommodates the distinct characteristics of email evidence will be presented. This process focuses on detecting the presence of non-obvious artifacts related to email accounts, retrieving the data from the service provider, and representing email in a well-structured format based on existing standards. As a result, developers and organizations can collaboratively create and use analysis tools that can analyze email evidence from any source in the same fashion and the examiner can access additional data relevant to their forensic cases. Following, an extensible framework implementing this novel process-driven approach has been implemented in an attempt to address the problems of comprehensiveness, extensibility, uniformity, collaboration/distribution, and consistency within forensic investigations involving email evidence.
ContributorsPaglierani, Justin W (Author) / Ahn, Gail-Joon (Thesis advisor) / Yau, Stephen S. (Committee member) / Santanam, Raghu T (Committee member) / Arizona State University (Publisher)
Created2013
Description
Natural photosynthesis dedicates specific proteins to achieve the modular division of the essential roles of solar energy harvesting, charge separation and carrier transport within natural photosynthesis. The modern understanding of the fundamental photochemistry by which natural photosynthesis operates is well advanced and solution state mimics of the key photochemical processes have been reported previously. All of the early events in natural photosynthesis responsible for the conversion of solar energy to electric potential energy occur within proteins and phospholipid membranes that act as scaffolds for arranging the active chromophores. Accordingly, for creating artificial photovoltaic (PV) systems, scaffolds are required to imbue structure to the systems. An approach to incorporating modular design into solid-state organic mimics of the natural system is presented together with how conductive scaffolds can be utilized in organic PV systems. To support the chromophore arrays present within this design and to extract separated charges from within the structure, linear pyrazine-containing molecular ribbons were chosen as candidates for forming conductive linear scaffolds that could be functionalized orthogonally to the linear axis. A series of donor-wire-acceptor (D-W-A) compounds employing porphyrins as the donors and a C60 fullerene adduct as the acceptors have been synthesized for studying the ability of the pyrazine-containing hetero-aromatic wires to mediate photoinduced electron transfer between the porphyrin donor and fullerene acceptor. Appropriate substitutions were made and the necessary model compounds useful for dissecting the complex photochemistry that the series is expected to display were also synthesized. A dye was synthesized using a pyrazine-containing heteroaromatic spacer that features two porphyrin chromophores. The dye dramatically outperforms the control dye featuring the same porphyrin and a simple benzoic acid linker. A novel, highly soluble 6+kDa extended phthalocyanine was also synthesized and exhibits absorption out to 900nm. The extensive functionalization of the extended phthalocyanine core with dodecyl groups enabled purification and characterization of an otherwise insoluble entity. Finally, in the interest of incorporating modular design into plastic solar cells, a series of porphyrin-containing monomers have been synthesized that are intended to form dyadic and triadic molecular-heterojunction polymers with dedicated hole and electron transport pathways during electrochemical polymerization.
ContributorsWatson, Brian Lyndon (Author) / Gust, Devens (Thesis advisor) / Gould, Ian (Committee member) / Moore, Ana L (Committee member) / Arizona State University (Publisher)
Created2013
ContributorsJin, Leon (Performer) / Duo, Hongzuo (Performer) / Bergstedt, David (Performer) / Ellis, Gage (Performer) / Novak, Gail (Performer) / ASU Library. Music Library (Publisher)
Created2021-02-24
ContributorsFletcher, Olivia (Performer) / Gatchel, David (Performer) / ASU Library. Music Library (Publisher)
Created2021-02-23