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- Genre: Masters Thesis
- Creators: Arizona State University
- Creators: Chakraborty, Bijeta
- Member of: ASU Electronic Theses and Dissertations
Description
ABSTRACT Research studies have demonstrated that stereotypes can elicit a priming response. An experiment was conducted to test the effects of priming elderly and young stereotypes on driving behavior. Participants drove in a driving simulator while navigating through two driving routes. Participants were guided by a neutral voice similar to "Siri" that informed them where to turn. Each route primed the participants with names that were deemed "old" or "young" as determined by a survey. The experiment yielded slower driving speeds in the elderly condition than in the young consistent with previous research regarding elderly stereotypes (Bargh et al, 1996; Branaghan and Gray, 2010; Taylor, 2010; Foster, 2012). These findings extend research on priming and behaviors elicited by participants in a simulated driving environment.
ContributorsThew, Lisa (Author) / Branaghan, Russell (Thesis advisor) / Song, Hyunjin (Committee member) / Kuzel, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
Efficiency of components is an ever increasing area of importance to portable applications, where a finite battery means finite operating time. Higher efficiency devices need to be designed that don't compromise on the performance that the consumer has come to expect. Class D amplifiers deliver on the goal of increased efficiency, but at the cost of distortion. Class AB amplifiers have low efficiency, but high linearity. By modulating the supply voltage of a Class AB amplifier to make a Class H amplifier, the efficiency can increase while still maintaining the Class AB level of linearity. A 92dB Power Supply Rejection Ratio (PSRR) Class AB amplifier and a Class H amplifier were designed in a 0.24um process for portable audio applications. Using a multiphase buck converter increased the efficiency of the Class H amplifier while still maintaining a fast response time to respond to audio frequencies. The Class H amplifier had an efficiency above the Class AB amplifier by 5-7% from 5-30mW of output power without affecting the total harmonic distortion (THD) at the design specifications. The Class H amplifier design met all design specifications and showed performance comparable to the designed Class AB amplifier across 1kHz-20kHz and 0.01mW-30mW. The Class H design was able to output 30mW into 16Ohms without any increase in THD. This design shows that Class H amplifiers merit more research into their potential for increasing efficiency of audio amplifiers and that even simple designs can give significant increases in efficiency without compromising linearity.
ContributorsPeterson, Cory (Author) / Bakkaloglu, Bertan (Thesis advisor) / Barnaby, Hugh (Committee member) / Kiaei, Sayfe (Committee member) / Arizona State University (Publisher)
Created2013
Description
Research on priming has shown that exposure to the concept of fast food can have an effect on human behavior by inducing haste and impatience (Zhong & E. DeVoe, 2010). This research suggests that thinking about fast food makes individuals impatient and strengthens their desire to complete tasks such as reading and decision making as quickly and efficiently as possible. Two experiments were conducted in which the effects of fast food priming were examined using a driving simulator. The experiments examined whether fast food primes can induce impatient driving. In experiment 1, 30 adult drivers drove a course in a driving simulator after being exposed to images by rating aesthetics of four different logos. Experiment 1 did not yield faster driving speeds nor an impatient and faster break at the yellow light in the fast food logo prime condition. In experiment 2, 30 adult drivers drove the same course from experiment 1. Participants did not rate logos on their aesthetics prior to the drive, instead billboards were included in the simulation that had either fast food or diner logos. Experiment 2 did not yielded faster driving speeds, however there was a significant effect of faster breaking and a higher number of participants running the yellow light.
ContributorsTaggart, Mistey. L (Author) / Branaghan, Russell (Thesis advisor) / Cooke, Nancy J. (Committee member) / Song, Hyunjin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Research on priming has shown that a stimulus can cause people to behave according to the stereotype held about the stimulus. Two experiments were conducted in which the effects of elderly priming were tested by use of a driving simulator. In both experiments, participants drove through a simulated world guided by either an elderly or a younger female voice. The voices told the participants where to make each of six turns. Both experiments yielded slower driving speeds in the elderly voice condition. The effect was universal regardless of implicit and explicit attitudes towards elderly people.
ContributorsFoster, L Bryant (Author) / Branaghan, Russell (Thesis advisor) / Becker, David (Committee member) / Cooke, Nancy J. (Committee member) / Arizona State University (Publisher)
Created2012
Description
Class D Amplifiers are widely used in portable systems such as mobile phones to achieve high efficiency. The demands of portable electronics for low power consumption to extend battery life and reduce heat dissipation mandate efficient, high-performance audio amplifiers. The high efficiency of Class D amplifiers (CDAs) makes them particularly attractive for portable applications. The Digital class D amplifier is an interesting solution to increase the efficiency of embedded systems. However, this solution is not good enough in terms of PWM stage linearity and power supply rejection. An efficient control is needed to correct the error sources in order to get a high fidelity sound quality in the whole audio range of frequencies. A fundamental analysis on various error sources due to non idealities in the power stage have been discussed here with key focus on Power supply perturbations driving the Power stage of a Class D Audio Amplifier. Two types of closed loop Digital Class D architecture for PSRR improvement have been proposed and modeled. Double sided uniform sampling modulation has been used. One of the architecture uses feedback around the power stage and the second architecture uses feedback into digital domain. Simulation & experimental results confirm that the closed loop PSRR & PS-IMD improve by around 30-40 dB and 25 dB respectively.
ContributorsChakraborty, Bijeta (Author) / Bakkaloglu, Bertan (Thesis advisor) / Garrity, Douglas (Committee member) / Ozev, Sule (Committee member) / Arizona State University (Publisher)
Created2012
Description
Modern day driving continues to burgeon with attention detractors found inside and outside drivers' vehicles (e.g. cell phones, other road users, etc.). This study explores a regularly disregarded attention detractor experienced by drivers: self-regulation. Results suggest self-regulation and WMC has the potential to affect attentional control, producing maladaptive changes in driving performance in maximum speed, acceleration, and time headway.
ContributorsSinocruz, Jerome Q (Author) / Sanchez, Christopher A (Thesis advisor) / Branaghan, Russel J (Committee member) / Becker, David V (Committee member) / Arizona State University (Publisher)
Created2012
Description
Previous literature was reviewed in an effort to further investigate the link between notification levels of a cell phone and their effects on driver distraction. Mind-wandering has been suggested as an explanation for distraction and has been previously operationalized with oculomotor movement. Mind-wandering’s definition is debated, but in this research it was defined as off task thoughts that occur due to the task not requiring full cognitive capacity. Drivers were asked to operate a driving simulator and follow audio turn by turn directions while experiencing each of three cell phone notification levels: Control (no texts), Airplane (texts with no notifications), and Ringer (audio notifications). Measures of Brake Reaction Time, Headway Variability, and Average Speed were used to operationalize driver distraction. Drivers experienced higher Brake Reaction Time and Headway Variability with a lower Average Speed in both experimental conditions when compared to the Control Condition. This is consistent with previous research in the field of implying a distracted state. Oculomotor movement was measured as the percent time the participant was looking at the road. There was no significant difference between the conditions in this measure. The results of this research indicate that not, while not interacting with a cell phone, no audio notification is required to induce a state of distraction. This phenomenon was unable to be linked to mind-wandering.
ContributorsRadina, Earl (Author) / Gray, Robert (Thesis advisor) / Chiou, Erin (Committee member) / Branaghan, Russell (Committee member) / Arizona State University (Publisher)
Created2019
Description
In this thesis, a digital input class D audio amplifier system which has the ability
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
to reject the power supply noise and nonlinearly of the output stage is presented. The main digital class D feed-forward path is using the fully-digital sigma-delta PWM open loop topology. Feedback loop is used to suppress the power supply noise and harmonic distortions. The design is using global foundry 0.18um technology.
Based on simulation, the power supply rejection at 200Hz is about -49dB with
81dB dynamic range and -70dB THD+N. The full scale output power can reach as high as 27mW and still keep minimum -68dB THD+N. The system efficiency at full scale is about 82%.
ContributorsBai, Jing (Author) / Bakkaloglu, Bertan (Thesis advisor) / Arizona State University (Publisher)
Created2015
Description
In 2013, 1.8 million US drivers were responsible for rear-end collisions with other vehicles (NHTSA 2014), for which driver distraction has been identified as the main factor (Campbell, Smith & Najm, 2003; Knipling, Mironer, Hendricks, Tijerina, Everson, Allen & Wilson 1993; Wang, Knipling & Goodman, 1996). The ubiquity of cell phones and their use behind the wheel has played a major role in distracting these drivers. To mitigate this, some manufacturers are equipping vehicles with forward collision warning (FCW) systems.
Generally, warnings that are perceived as being urgent produce lower response times. One technique for increasing perceived urgency of a warning is called looming, where the signal increases in or more dimensions over time. Looming warning signals have been shown to produce low response times, likely because the recipient perceives the signal as a potential approaching threat, prompting defensive reactions (Graziano and Cooke, 2006).
The present study evaluates the effect of veridical (intensity increases at the rate of closure with the lead vehicle) and high urgency (intensity increases at a rate of Time to Collision minus 0.5 seconds) looming FCW, as well as a static FCW, on drivers’ brake reaction times in the presence of a secondary texting task. Participants’ brake reaction times were recorded as they followed a lead car in a driving simulator, encountering multiple sudden-braking events across the five conditions (a control condition as well as four counterbalanced conditions using a secondary texting task). In the four conditions with a secondary task, participants received no FCW, static FCW, veridical FCW, and high-urgency FCW, respectively. Performance data was analyzed using a repeated measures ANOVA, and a series of pairwise comparisons were then made using Bonferroni corrected pairwise t-tests.
The presence of a visually and manually distracting secondary task (texting) seems to diminish the performance of the looming signals as compared to previous studies that did not use a distraction component. While looming FCW do seem to effectively lower BRTs when the driver is distracted, it is recommended that further research investigate the relationship between secondary task types and their respective levels of distraction, and the effectiveness of auditory looming FCW.
Generally, warnings that are perceived as being urgent produce lower response times. One technique for increasing perceived urgency of a warning is called looming, where the signal increases in or more dimensions over time. Looming warning signals have been shown to produce low response times, likely because the recipient perceives the signal as a potential approaching threat, prompting defensive reactions (Graziano and Cooke, 2006).
The present study evaluates the effect of veridical (intensity increases at the rate of closure with the lead vehicle) and high urgency (intensity increases at a rate of Time to Collision minus 0.5 seconds) looming FCW, as well as a static FCW, on drivers’ brake reaction times in the presence of a secondary texting task. Participants’ brake reaction times were recorded as they followed a lead car in a driving simulator, encountering multiple sudden-braking events across the five conditions (a control condition as well as four counterbalanced conditions using a secondary texting task). In the four conditions with a secondary task, participants received no FCW, static FCW, veridical FCW, and high-urgency FCW, respectively. Performance data was analyzed using a repeated measures ANOVA, and a series of pairwise comparisons were then made using Bonferroni corrected pairwise t-tests.
The presence of a visually and manually distracting secondary task (texting) seems to diminish the performance of the looming signals as compared to previous studies that did not use a distraction component. While looming FCW do seem to effectively lower BRTs when the driver is distracted, it is recommended that further research investigate the relationship between secondary task types and their respective levels of distraction, and the effectiveness of auditory looming FCW.
ContributorsBecker, Mike (Author) / Gray, Robert (Thesis advisor) / Branaghan, Russell (Committee member) / Craig, Scotty (Committee member) / Arizona State University (Publisher)
Created2016
Description
The issue of women driving remains to be highly debated in Saudi Arabia. Recent developments on its legalization have sparked conversation and discourse, particularly in social media sites like Twitter. Several hashtags have been used to indicate either support or criticism towards the movement.
Examining Twitter tweets and hashtags, the study explored how the discourse on women driving had been executed, particularly in between genders. The study analyzed a sizeable number of tweets as well as their context via linguistic corpora analysis. Following Norman Fairclough’s framework, the two opposing perspectives were investigated both at a level of textual analysis. The selected tweets were representative of the three hashtags that emerged on the heat of the discourse regarding the issue of women driving in Saudi Arabia: #Women_car_driving, #I_will_drive_my_car_June15, and #I_will_enter_my_kitchen_June15.
The results showed, among others, that tweets with the hashtag #Women_car_driving presented a tremendous support towards the movement. On the other hand strong opposing reactions emerged from the hashtags #I_will_drive_my_car_June15 and #I_will_enter_my_kitchen_June15.
Examining Twitter tweets and hashtags, the study explored how the discourse on women driving had been executed, particularly in between genders. The study analyzed a sizeable number of tweets as well as their context via linguistic corpora analysis. Following Norman Fairclough’s framework, the two opposing perspectives were investigated both at a level of textual analysis. The selected tweets were representative of the three hashtags that emerged on the heat of the discourse regarding the issue of women driving in Saudi Arabia: #Women_car_driving, #I_will_drive_my_car_June15, and #I_will_enter_my_kitchen_June15.
The results showed, among others, that tweets with the hashtag #Women_car_driving presented a tremendous support towards the movement. On the other hand strong opposing reactions emerged from the hashtags #I_will_drive_my_car_June15 and #I_will_enter_my_kitchen_June15.
ContributorsAljarallah, Rayya Sulaiman (Author) / Adams, Karen (Thesis advisor) / Gelderen, Elly van (Committee member) / Prior, Matthew (Committee member) / Arizona State University (Publisher)
Created2017