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Detecting Rip Currents from Images
Get PDFRip current images are useful for assisting in climate studies but time consuming to manually annotate by hand over thousands of images. Object detection is a possible solution for automatic annotation because of its success and popularity in identifying regions of interest in images, such as human faces. Similarly to faces, rip currents have distinct features that set them apart from other areas of an image, such as more generic patterns of the surf zone. There are many distinct methods of object detection applied in face detection research. In this thesis, the best fit for a rip current object detector is found by comparing these methods. In addition, the methods are improved with Haar features exclusively created for rip current images. The compared methods include max distance from the average, support vector machines, convolutional neural networks, the Viola-Jones object detector, and a meta-learner. The presented results are compared for accuracy, false positive rate, and detection rate. Viola-Jones has the top base-line performance by achieving a detection rate of 0.88 and identifying only 15 false positives in the test image set of 53 rip currents. The described meta-learner integrates the presented Haar features, which are developed in accordance with the original Viola-Jones algorithm. Ada-Boost, a feature ranking algorithm, shows that the newly presented Haar features extract more meaningful data from rip current images than some of the current features. The meta-classifier improves upon the stand-alone Viola-Jones when applying these features by reducing its false positives by 47% while retaining a similar computational cost and detection rate
Asphalt Magnolias: Women in Southern State Police and Highway Patrol Agencies, 1972-2012
Get PDFWomen are under-represented in both numbers and at the command level of police agencies after over 40 years of women in policing. The national average for women in policing, as reported by the 2012 Federal Bureau of Investigation Uniform Crime Report, was 11.9%. Women in state police and highway patrol agencies are well below the national average, particularly in the southern states where the percentage is below 6%. This study uses qualitative data to examine the role of gender and the gendered organizational structure and culture of police agencies through interview data from 24 women troopers and one academy cadet who are or were employed in seven southern state police and highway patrol agencies between 1972 and 2012. The data from their lived experiences indicate that women continue to encounter barriers and challenges to recruitment, employment, assignment, retention, and promotional opportunities. Understanding how women experience paramilitary policing institutions and the gendered nature of a male-dominated workforce can be used to argue for meaningful social and organizational changes in state police and highway patrol agencies and, by association, the profession of policing.
Keywords: gendered roles, gendered institutions, gendered structure organizations, gendered culture, police, troopers, state police, highway patrol, women police, leadership, hegemonic masculinity, gende
The Experiential Journey of Teacher-Scholars: βIf youβre not a teacher, you just donβt get itβ
Get PDFThe Center of Graduate Schools (2015) published a report detailing applications, enrollment, and trends in graduate schools across the nation showing that approximately one third of all first-time graduate school applicants in masterβs degree programs utilizing the GRE assessment identify their career path in either business or teacher education. The purpose of this study was to examine the lived experiences of classroom teachers who concurrently pursued graduate studies to earn a masterβs degree in education and to understand how adult learning provided opportunities for personal growth and the attainment of professional goals. Individual interviews and two focus groups were conducted to uncover the essence of experiences across participant stories. Seven themes emerged from the data: 1) Teacher-scholarsβ reasons for returning to higher education varied based on their personal and professional needs, 2) The teacher-scholar experience elicits a vast array of emotions, challenges, and successes, 3) Teacher-scholars were self-driven to start their programs however intrinsic and extrinsic motivation provided encouragement for continued desire for success, 4) Teacher-scholarsβ support systems were integral to their success in their masterβs programs, 5) Teacher-scholars were reflective about their teaching and learning and used reflection as a tool to improve their professional capabilities, 6) Teacher-scholars used concrete learning experiences to bring their learning into their classrooms and professional lives, and 7) Teacher-scholarsβ educational journeys provided opportunities for here-and-now learning as well as increased marketability for a future in the field of education. Additionally, a revision to David Kolbβs Experiential Learning Cycle (2015) was presented. Participant data highlighted collaboration as a necessary component to teacher-scholar success yet it was not addressed in Kolbβs original model. Results from this study can be used to inform teacher education programs as well as teacher-scholars on the expectations, experiences, and perceptions of teachers who concurrently pursued higher education
Active Vibration Control of Helicopter Rotor Blade by Using a Linear Quadratic Regulator
Get PDFActive vibration control is a widely implemented method for the helicopter vibration control. Due to the significant progress in microelectronics, this technique outperforms the traditional passive control technique due to weight penalty and lack of adaptability for the changing flight conditions. In this thesis, an optimal controller is designed to attenuate the rotor blade vibration. The mathematical model of the triply coupled vibration of the rotating cantilever beam is used to develop the state-space model of an isolated rotor blade. The required natural frequencies are determined by the modified Galerkin method and only the principal aerodynamic forces acting on the structure are considered to obtain the elements of the input matrix. A linear quadratic regulator is designed to achieve the vibration reduction at the optimum level and the controller is tuned for the hovering and forward flight with different advance ratios