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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

Blast Response of Composite Sandwich Panels

Palla, Leela Prasad January 2008 (has links)
No description available.
312

Efficacy of Partial ROM Squat in Maximal Strength Training

Bazyler, Caleb 01 August 2013 (has links) (PDF)
Eighteen well trained males (1RM Squat: 150.57 ± 26.79 kg) were assigned to two groups: full ROM training (control) and full ROM with partial ROM training (CP) for the seven-week training intervention. There was a significant time effect (p
313

An Investigation into the Structure of Self-Control

Dreves, Parker A 01 May 2019 (has links) (PDF)
Self-control has been measured using a variety of methods including self-report measures, cognitive inhibition tasks, delay discounting and delay of gratification tasks, and persistence and willpower tasks. Although these are all theoretically linked to processes involved in self-control, recent evidence has shown that these diverse measurement techniques relate only minimally to one another. Assuming that self-control is a reflective construct, this would indicate that many of these tasks are poor indicators of self-control. The present research challenges the common assumption that self-control is a reflective construct and instead proposes that self-control is a formative construct. Conceptualizing self-control as a formative construct could reconcile some of the inconsistencies in the literature, in particular the fact that many indicators for self-control do not correlate highly. To examine the possibility of a formative model of self-control, this research examines 13 commonly used measures of self-control and investigates indicator intercorrelations, indicator relationships with the theoretical consequences of self-control, and performs a vanishing tetrad test (Bollen & Ting, 2000). Results show that in general, indicator intercorrelations are low and nonsignificant as well as indictor correlations with theorized construct consequences. The results of the vanishing tetrad test suggest a reflective interpretation of self-control, but concerns with uniformly low covariances between indicators limit the interpretation of this test.
314

Acoustics of the Salt Lake Tabernacle: Characterization and Study of Spatial Variation

Rollins, Sarah 21 November 2005 (has links) (PDF)
In order to preserve the acoustics of the Salt Lake Tabernacle after the seismic renovation of 2005-2006, it was necessary to characterize these acoustics immediately preceding the renovation. This thesis discusses the characterization process that began with the measurement of hundreds of impulse responses for five different source positions and several receiver locations throughout the hall seating areas. The acoustics were further characterized by deriving various parameters from these responses that correlate with subjective preferences for music and speech. Impulse responses were also generated by a CATT-Acoustic™ computer model of the Tabernacle for the same purpose. The parameter values were then mapped over diagrams of the seating areas of the hall to show the spatial variation of the acoustics. To further investigate the variation, statistics were calculated for each parameter and an algorithm was developed to determine the minimum number of receiver locations necessary to adequately characterize the hall. Computer models were also used to investigate focusing effects of the curved ceiling and historical comments made about the improvements to the acoustics with addition of the balcony in 1870.
315

Development and Comparison of Methods for Measuring Directional Sound Arrivals in Rooms

Thornock, Brian Trevor 06 October 2009 (has links) (PDF)
In room acoustics, the directional information of sound arrivals at a listening location can be used to diagnose the origins of problematic reflections so offending surfaces or other features can be properly treated. It can also be used for other purposes, including the study of psychoacoustic indicators. Many methods have been developed in the past to derive directional information, but despite their benefits, each has had significant drawbacks that have necessitated further research into their properties and development of an improved method. This thesis presents a review of past methods, their benefits and shortcomings. It discusses many theoretical and practical issues pertaining to the Polar ETC method and methods using the cross-correlation function. It also presents a new short-time correlation-based method (STCM) for gathering directional information of sound arrivals in rooms. Computer programs were developed for the implementation of the theory. Numerical simulations and experimental measurements are shown and the results are compared to those obtained by the Polar Energy Time Curve (ETC) method. The STCM is shown to be an improvement over past methods in terms of its ability to distinguish between simultaneous arrivals, its accuracy, its computational efficiency and its equipment requirements. Limitations of the method are also discussed.
316

Are our Hedonic Motivation and Emotions Triggered by Influencers’ Monetary Sales Promotions to Impulse Buy Online? : An explanatory study

Marin, Bianca, Bergström, Michelle, Memisevic, Anneli January 2022 (has links)
Background: Social media influencers provide their followers with different monetary sales promotions to increase purchases by the brands they endorse. Hedonic motivation and emotions initiate each other and are fulfilled through consumers' need to act. As a result, monetary sales promotions will encourage consumers to buy unplanned purchases. Previous research recommends additional quantitative research on sales promotions and influencers, and others propose more research to fill the gap on influencers' impact on society. The interest lies in how these, in turn, affect consumers' impulsive buying behavior.  Purpose: This study aims to explain the effects of hedonic motivation and emotions, triggered by social media influencers' monetary sales promotions on consumers' impulse buying online.   Methodology: This paper is explanatory, with a deductive approach to research while utilizing a quantitative strategy to achieve a cross-sectional research design. The study has three hypotheses that were deducted based on the concepts within the theoretical framework, and the data was collected through a self-completion questionnaire to receive its final results: if the hypotheses were rejected or accepted. Furthermore, the questionnaire received a total of 105 responses. Findings: All hypotheses were statistically insignificant when tested with the control variables. However, hedonic motivation was accepted when disregarding the control variables by only testing the independent variables against the dependent. Nevertheless, all hypotheses are rejected based on their statistical insignificance. Furthermore, the findings portray that the variables are too intercorrelated. While the results did not provide any practical contribution, it acknowledged the difficulties with measuring hedonic motivation, pleasure, and arousal simultaneously with impulse buying online.   Conclusion: Based on the findings of this study, it is concluded that there are no positive effects of hedonic motivation and emotions and that these are triggered by social media influencers' monetary sales promotion on consumers' impulse buying behavior online.
317

Positive Impulse Phase versus Propulsive Impulse Phase: Correlations between Asymmetry and Countermovement Jump Performance

Painter, Keith B., Hornsby, William G., Carroll, Kevin, Mizuguchi, Satoshi, Stone, Michael H. 05 April 2022 (has links)
The relationship between asymmetry and performance is still undetermined in the literature. Methods of assessing asymmetry have been inconsistent and focused on the analysis of jumping asymmetry. Dual ground reaction forces are prevalent in athlete monitoring, though underutilized in asymmetry research. The purpose of this study was to assess the relationship of countermovement jump (CMJ) impulse asymmetry to performance in collegiate soccer athletes. Male and female athletes were selected from an ongoing athlete research repository database of NCAA D-I soccer athletes. All athletes contributed two maximal effort unweighted (CMJ0) and weighted countermovement jumps (CMJ20) using the mean for calculations. Propulsive phase asymmetry scores (PrPAS) and positive impulse asymmetry scores (PIAS) were calculated to determine the magnitude of asymmetry for each prospective phase. Statistically significant correlations were found between CMJ0 jump height and unweighted PIAS ( = -0.43) in females. Males had statistically significant correlations between CMJ20 jump height and weighted PIAS ( = -0.49). Neither unweighted PrPAS nor weighted PrPAS produced statistically significant correlations ( < 0.26) to their prospective jump heights. When assessing CMJ asymmetry, it is recommended to conduct both weighted and unweighted CMJ testing, utilizing PIAS as the metric to be assessed.
318

Impulsivity And Attention-Deficit/Hyperactivity Disorder (ADHD) Testing Competing Predictions From The Working Memory And Behavioral Inhibition Models Of Adhd

Raiker, Joseph S 01 January 2011 (has links)
Impulsivity is a hallmark of two of the three DSM-IV ADHD subtypes and is associated with myriad adverse outcomes. Limited research, however, is available concerning the mechanisms and processes that contribute to impulsive responding by children with ADHD. The current study tested predictions from two competing models of ADHD – working memory (WM) and behavioral inhibition (BI) – to examine the extent to which ADHD-related impulsive responding was attributable to model-specific mechanisms and processes. Children with ADHD (n = 21) and typically developing children (n = 20) completed laboratory tasks that provided WM (domaingeneral central executive [CE], phonological/visuospatial storage/rehearsal) and BI indices (stopsignal reaction time [SSRT], stop-signal delay, mean reaction time). These indices were examined as potential mediators of ADHD-related impulsive responding on two diverse laboratory tasks used commonly to assess impulsive responding (CPT: continuous performance test; VMTS: visual match-to-sample). Bias-corrected, bootstrapped mediation analyses revealed that CE processes significantly attenuated between-group impulsivity differences, such that the initial large-magnitude impulsivity differences were no longer significant on either task after accounting for ADHD-related CE deficits. In contrast, SSRT partially mediated ADHD-related impulsive responding on the CPT but not VMTS. This partial attenuation was no longer significant after accounting for shared variance between CE and SSRT; CE continued to attenuate the ADHD-impulsivity relationship after accounting for SSRT. These findings add to the growing literature implicating CE deficits in core ADHD behavioral and functional impairments, and suggest that cognitive interventions targeting CE rather than storage/rehearsal or BI processes may hold greater promise for alleviating ADHD-related impairments
319

Design of a Low Power Cargo Security Device Using a Micropower Ultra-Wideband Impulse Radar

Wihl, Brian M 01 December 2013 (has links) (PDF)
Each year, thousands of cargo containers are broken into during shipping, costing billions of dollars in lost and damaged goods. In addition to removing its contents, intruders can also add unwanted and dangerous materials to a container, posing a threat to National Security. The possibilities of cargo container break-ins require that the containers go through check points at which they are physically searched. These searches often require the opening of the container, unloading and inspecting all cargo, and then loading the container and resealing it. This is a long and costly process. Because of the high costs of break-ins and inspections, many security devices have been developed to ensure the safety and detect the tampering of cargo containers. Most of these mechanisms involve more intricate door locks and electronic seals that are able to add a degree of security to the containers. Other “smart” cargo security devices exist, which employ a variety of sensors to detect intrusion, however, none of the current solutions are reliable and practical enough to eliminate the necessity for frequent inspection of cargo containers. The shipping industry is in need of a reliable, unobtrusive, low-cost, low-effort cargo security device. Over the last two decades, Lawrence Livermore National Laboratory (LLNL) has been developing a micropower impulse radar capable of detecting objects and motion within a short to medium range. Due to its past uses for intrusion and motion detection, the LLNL micropower impulse radar is a top prospect for a sensor technology used in a cargo security device. This paper describes the design of a low-power, low-cost cargo security device which uses the LLNL micropower impulse radar for the detection of shipping container intrusions. With the evaluation of the impulse radar as well as various other sensors, a device was created which successfully detected intrusions over 98% of the time with the capability of lasting 5 to 6 months when powered by two AA batteries.
320

Channel Impulse Response and Its Relationship to Bit Error Rate at 28 GHz

Miniuk, Mary 10 February 2004 (has links)
Over the years, the Internet has become increasingly popular and people's dependence on it has increased dramatically. Whether it be to communicate to someone across the world, find blueprints, or check sports scores, the Internet has become a necessary resource for everyone. In emergency situations, this need increases further. After the terrorist attacks on the Pentagon, it took several days to restore communications. This is not an acceptable time frame when people's lives are at stake. Virginia Tech's Center for Wireless Telecommunication has developed a prototype of a rapidly deployable high bandwidth wireless communication system at 28 GHz (Local Multipoint Distribution Service frequency). This system provides a large bandwidth radio link to a disaster zone up to 5 km away and puts Ethernet speeds and 802.11 accesses to users within hours. Because of the possible variability in locations that the system can be deployed, it is necessary to find the most useable channel at the site as quickly as possible. In addition to 28GHz radio links, the system also has a built-in channel sounder that measures and captures the channel impulse response of the current channel. Until now, there has been limited research on the relationship between the channel impulse response and the usability of the channel quantified using bit error rate. This thesis examines several different channels captured by CWT's channel sounder and simulates the BER using Cadence's SPW with time-domain models of the channels. This thesis goes on further to show that BER greatly depends on the channel impulse response and the symbol rate. / Master of Science

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