• A Heuristic to Reduce the Maximum Work-in-Process for Aircraft Maintenance

      Verhine, Harrison Mikeal; School of Engineering
      Air Logistics Complexes (ALCs) provide depot maintenance for aircraft fleets for the United States Air Force (USAF). The rate at which aircraft are inducted into maintenance is in constant flux. For example, initiation of new modification programs, aging aircraft fleets, and demand for new work all impact future workload requirements and planning. The induction schedule identifies the dates that aircraft arrive at a maintenance depot. A good induction schedule can help minimize flow days (time an aircraft is in maintenance) while a poor induction schedule can result in increased work-in-process (WIP) and long aircraft maintenance queues. Depot maintenance can be modeled as a job shop scheduling problem. Many heuristics and metaheuristics have been proposed to solve variations of job shop problems. This paper utilizes a simulation tool, RAMP, which was developed to simulate the maintenance performed on aircraft and produces results about the utilization, queue lengths, and other performance metrics of the system. This thesis describes a developed heuristic, which is used to alter induction schedules in order to smooth WIP curves and reduce queue times. The algorithm keeps most of the induction schedule un-altered by manipulating induction dates for a relative few aircraft around important times in the simulation, namely around large extrema. The algorithm uses a numerical derivative and an application of the second derivative test to detect important extrema. Once these extrema are identified, it attempts to reduce aircraft WIP around peaks and fill aircraft WIP into valleys. This is performed by shifting the induction dates of aircraft around those extrema. The algorithm was successful in reducing the maximum WIP for 12 out of 16 schedules tested. Of the successful runs, there was an average improvement of 8.7% on maximum WIP. Performance of the heuristic is dependent on the parameters used; however, modifications were made to mitigate this dependence. The algorithm can function well in its current version; however, there is still additional work that can be done to further increase performance.
    • A Mixed Methods Study Of The Symptom Experience Following Endovascular Treatment For Lower Extremity Peripheral Arterial Disease

      Gramling, Serena Greenhaw
      Peripheral arterial disease (PAD) is one of the most understudied and undertreated diseases affecting three to ten percent of the general population. Patients with lower extremity PAD must manage multiple symptoms including pain in the hips, thighs, and calves during rest and physical activity. However, evidence is limited about patients' experience, especially following treatment. The purpose of this mixed methods study was to explore the symptom experience of individuals with peripheral arterial disease following endovascular treatment including perceptions of treatment benefit and concerns. Using a convergent parallel mixed methods study design, 65 participants (mean age = 56.9 years, 73.8% female, 95.4% white) participated in a web-based survey. Quantitative data were collected utilizing six questionnaires: a researcher developed demographic and clinical history questionnaire, the Patient Health Questionnaire 9 (PHQ-9), the Walking Impairment Questionnaire (WIQ), the San Diego Claudication Questionnaire (SDCQ), the VascuQOL-25, and the Peripheral Artery Questionnaire (PAQ). Qualitative data were collected using open-ended questions within the web-based survey. The most commonly reported symptom by participants was pain in both legs while walking. Greater age was significantly associated with less symptoms, less pain, being more active, and being more social. Men reported better physical functioning, walking ability, and overall quality of life compared to women. Participants with PHQ-9 scores indicative of depression reported greater difficulty controlling their symptoms. No significant relationships were found between having a diagnosis of diabetes and symptom experience or quality of life. Qualitative data analysis revealed four themes. One theme concerning benefits of treatment was described as continuum of benefit. The three themes related to concerns with treatment were described as outcome, process, and coping. Qualitative data supported the quantitative results related to symptom experience, gender, and depression. Qualitative data diverged with the quantitative results related to age as within the qualitative data younger participants reported more positive treatment outcomes than older participants. The findings from this study have the potential to provide better insight into the experiences of individuals with PAD and guide interventions for improved care and outcomes.
    • A Multiple Case Study Of How Three Lighthouse Middle Schools Meet The Needs Of Gifted And Talented Young Adolescents

      Wetherington, Terry
      The middle school years, grades sixth through eighth, have been identified as a time when gifted and talented young adolescents’ needs have not been met. The Association for Middle Level Education (AMLE) and the National Association for Gifted Children (NAGC) agreed that gifted and talented young adolescents have needs which may differ from their peers and should be addressed by educators. There were no research studies of how schools identified as exemplary middle schools by the Forum to Accelerate Middle Grades Reform and designated as Georgia Lighthouse Schools To Watch © met the needs of gifted and talented young adolescents. The purpose of this multiple case study was to describe how the needs of gifted and talented young adolescents were met at three Georgia Lighthouse Schools To Watch ©. The following research question was a guide for this investigation: how are the needs of gifted and talented young adolescents met at three Georgia Lighthouse Schools To Watch © within the middle school philosophy? Three cases were selected using purposeful criterion sampling from designated Georgia Lighthouse Schools To Watch © as identified on the Georgia Middle School Association website. A qualitative multiple case study design was used. Participants included principals and teachers from three Georgia Lighthouse Schools To Watch ©. Data were collected using interviews, focus groups, and documents analyzed. Data were analyzed using single case analyses and a cross-case analysis where categories and subcategories were identified as well as similarities and differences between the findings of each case. The research findings were organized and reported based on the following categories which emerged during data analysis: (a) middle school philosophy and gifted education, (b) identification and grouping of gifted students, (c) services, (d) assessment, and (e) professional learning opportunities. Research findings indicated the needs of gifted and talented young adolescents were met when educators intentionally implemented services with differentiated curriculum and instruction based on individual needs. Future research is needed to better identify, refer, and serve students who are typically underrepresented in gifted programmings such as economically disadvantaged students, students with disabilities, and students from cultural and ethnic minorities.
    • A Narrative Inquiry of Work-Life Balance Among Faculty Mothers in Higher Education

      Riley, Lozarie; Tift College of Education
      Despite women outnumbering men as doctoral degree recipients, women remain underrepresented in higher education leadership roles. Specifically, women at the childbearing age serving as faculty often face challenges such as inadequate maternity leave and family policies that impede pathways for tenure, promotion, and elevation to senior administration. As such, the aim of this study was to explore the work-life balance experiences related to maternity leave and/or family policies of female employees on the path to higher education leadership. To address the research questions of this study, the researcher utilized narrative inquiry to capture the stories of four faculty mothers who gave birth and took a maternity leave period while working to earn tenure. Women’s Ways of Knowing theory served as a framework to understand how participants made sense of their experience. Through core story creation, developed by Polkinghorne (1988) and further extended by Emden (1998), narrative analysis of the stories resulted in a narrative specific to each participant, as well as a narrative of the faculty mother work-life balance culture. Four themes emerged that offer recommendations to advance the faculty mother work-life balance experience: Mentorship, Support to Return to Work After Leave, Advancing Leave Policies, and Work-Life Balance. The findings of this study implied that faculty mothers are disadvantaged by the Family Medical Leave Act, while desiring the creation of university level leave policies specific to pregnancy and motherhood. Recommendations for future studies include qualitative and quantitative study designs.
    • A Narrative Study Of Foster Youth Perceptions Of Learning Climate Through A Self Determination Lens

      Ward, Kim
      ABSTRACT A NARRATIVE STUDY OF FOSTER YOUTH PERCEPTIONS OF LEARNING CLIMATE THROUGH A SELF DETERMINATION LENS Under the direction of KAREN WELLER SWANSON, Ed. D. Foster youth or former foster youth face many educational, social, and emotional struggles in the classroom. Through a lens of self-determination, this study investigates the perceptions of foster youth or former foster youth about teacher autonomy support in the classroom, as well as how they perceive that teacher autonomy support affects their motivation and achievement. The five themes that arose from research question one in this study are: Theme 1 – Acceptance, Respect, Understanding, Family-Like Atmosphere; Theme 2 – Confidence, Trustworthiness, and Encouragement; Theme 3 – Understanding the Goal of the Class; Theme 4 – Comfortable Learning Environment for Dialogue and Listening; and Theme 5 – Choices and Options in the Classroom. These themes suggest ways that teachers can provide for the needs of foster youth while also improving their motivation and academic performance. The four themes which emerged from research question two are: Theme 1 - Confidence, Theme 2 - Motivation; Theme 3 – Inspiration; and Theme 4 – Emotional State. These themes concern the effect on the foster child of having autonomy supportive requirements met.
    • A Novel Design Of A Hip Brace Mechanism For Rehabilitation Of Limited Range Of Motion

      Leslie, Morgan
      Osteoarthritis (OA) and femoroacetabular impingement (FAI) are both conditions that can cause destruction of the hip joint – resulting in pain, limited range of motion, and gait imbalances. The purpose of this study is to analyze the gait and muscle activity in patients with OA and FAI and propose and test the effectiveness of a rehabilitative mechanism that aims to help balance muscle activity to improve gait. Each of the three subjects (one baseline, one with FAI, and one with OA) underwent electromyographic (EMG) analysis and 2-D gait analysis for three conditions: with no brace, with just the brace, and with the mechanism. The FAI subject showed low peak gluteal activity in the affected side compared to the unaffected (14.70% less affected gluteus medius (GMD), 11.77% less affected gluteus maximus (GMX)). The device increased GMD activity on the affected side to be closer to that of the unaffected side at 5.5% less. The GMX peak activity increased by 21.83%, even though the affected side was still less by 11.51%. The OA subject showed higher mean gluteal activity on the affected side when compared to the unaffected side. The GMD and GMX activity was 9.6% and 0 7% greater, respectively. With the device added, the GMD and GMX means on the affected side was 13.6% and 0.7% greater, respectively. The subject with FAI showed at 14.57o less hip range of motion (ROM) on the affected side when compared to the baseline value of 50o. When the device added, the ROM decreased further by 1.79o. The FAI subject showed 2.42o more pelvis ROM than that of the baseline subject. With the device, the difference between the FAI subject and the baseline subject was only 0.61o. The OA subject showed a percent difference less of 33.06% between his double step length on the affected side and the normal value of 1.41 m. With the device, the percent difference less becomes 29.27%. With no brace or device, this subject shows 7.7% less time in stance phase than the normal value of 60% and only 0.83% more when the device is worn. Finite element analysis (FEA) was conducted to determine the mechanical integrity and fatigue life of the mechanism and free body diagrams (FBDs) with calculations were done to estimate the change in muscular forces with the mechanism. The FEA found a maximum stress of 32.51 ksi. The margin of safety for fatigue of an unnotched condition was calculated to be 2.46. In a notched case, the cycles until failure was determined to be 213,797 cycles. The FBDs found that there is a muscle activity increase of 4.3% and 2.6% for extension and flexion, respectively. Future studies would need to be done with a larger pool of subjects, different design ideas (to optimize results), and trials done after the subjects have used the device for a time.
    • A Novel Design of a Knee Brace for Patients with Spinocerebellar Ataxia: A Comparative Study

      Speece, Brooke; School of Engineering
      Spinocerebellar ataxia (SCA) is an inherited degenerative disease of the central nervous system leading to the deterioration of the cerebellum, the voluntary motor control center of the brain. Patients with SCA are unable to maintain balance and normal posture and have an ataxic gait, resulting in increased abnormalities in gait parameters. Some patients may increase muscle co-activation to provide stability during gait by stiffening their joints. A compensation that typically results in reduced joint range of motion and a decrease of gait parameters. The subject of this study is a 47-year-old female with spinocerebellar ataxia type 2 and presents with difficulty standing, abnormal ataxic gait, and poor balance. The purpose of this study was to design and construct a brace to provide stability and aid the patient in walking as well as standing and sitting. Two braces were designed, constructed, and tested to compare the efficacy of each: a tension brace with an adjustable Velcro tension band attachment on the anterior portion of the brace and a spring brace with a torsional spring and 3D printed housing attached to the brace knee joint. Electromyography analysis determined the knee antagonist co-activation index (CAI) increased by 86.3% during stance and by 168.7% during swing with the spring brace, indicating greater stability and motor control. The tension brace had little to no effect on CAI. During standing, the tension brace increased quadriceps activity by 65.4% and the spring brace increased activity by 37.2%, indicating both braces could help to rehabilitate weak muscle function. Joint angle diagrams obtained in the gait analysis determined both braces aid the knee during the terminal stance and pre-swing. With the spring brace, cadence increased by 8.7% (72.4 steps/min) and velocity by 8% (0.53 m/s), while the tension brace increased cadence 4.9% (69.7 steps/min) and velocity remained unchanged. The F-Scan pressure analysis determined the spring brace decreases abnormal peak force during loading which can indicate balance problems at heel strike. The patient preferred using the spring brace to the tension brace. She felt it provided her more stability and speed and elected to keep the brace after testing.
    • A NOVEL DESIGN OF AN ANKLE BRACE TO STABILIZE THE ANTERIOR TALOFIBULAR LIGAMENT DURING ACTIVITY

      Williams, Jania D; School of Engineering
      Acute ankle sprains are one of the most common musculoskeletal injuries that affect everyone. Gait and muscle strength are negatively impacted, especially by chronic ankle sprains. The period of rest and immobilization causes muscle atrophy from nonuse. In this study, three braces were used: a hinged design, lace up, and engineered brace. The engineered brace’s main components are neoprene material, a drawstring, and elastic band. Three testing systems were used to capture data: Mat Scan, 2D gait analysis, and electromyography (EMG). Mat Scan uses a pressure mat for single and double limb support balancing. 2D gait analysis uses Simi Aktisys software to test movements of the hip, knee, and ankle joint with LED markers. EMG measures muscle activity from electrical signals of the targeted muscles: tibialis anterior(TA), peroneal longus(PL), lateral gastrocnemius(LG), and medial stabilizing structures(MSS), bilaterally at 3 walking speeds. Mat Scans COF testing revealed anterior shifts due to higher activity from plantar flexors. Patients compensate for muscle weakness by increasing loads on the anterior portion of one limb and the posteriorly on another. The hinged design brace increased pressure and load to the uninjured limb. The elastic band from the engineered brace and the lace up style brace’s compression enabled the joint to bear more weight and perform optimally. A one-way ANOVA was used to analyze the hip, knee, and ankle for each phase at all three speeds combined. All joints exceeded the confidence interval, except for the hip joint in the engineered brace. This phase also contained the lowest p-values. Analyzing the EMG data revealed the muscle strength and tendon condition. TA performed consistently and best in initial data. PL had optimal performance while wearing the lace up and engineered brace due compression. LG performed poorly in all designs due to a lack of support in stabilizing the joint. MSS performed the most inconsistently, but the best when lateral support was present, like the engineered brace. Expansion of this research should include manipulation of the tension band to vary in width and strength. Athletes and patients with preexisting conditions displayed the need for specialized sizing and bracing options.
    • A Painting of Cultural Mismatch: A Case Study Exploring thee Relationship Between Teacher Perceptions of Black English and Their Instructional Choices

      Evans, Amberly; Tift College of Education
      Most U.S. Black students experience a cultural mismatch when they attend U.S. public schools, which usually subscribe to Eurocentric Anglo-Saxon cultural norms, as seen throughout the curriculum, literature selection, and rules and norms. One consequence of this mismatch is lower mastery level performance of Black students on standardized national reading and mathematics assessments than their White peers. Thus, the current education system is oppressive toward Black students, for it denies access to a culturally and linguistically affirming education that reflects and sustains their cultural ways of being. This research aimed to better understand current teacher perceptions of Black English use in the classroom and how those perceptions influence instructional decisions made by teachers of Black English-speaking students. Applying the principles of a case study with elicitation and traditional interviews and document analysis, the researcher studied six elementary teachers of Black English speakers. The major conceptions identified across participants’ responses were that teachers held positive perceptions of Black English use outside of school but struggled to transfer those same perceptions to their instructional decisions. More often teachers viewed their role as responsible for equipping students for the future and obligated to teach prescribed standards and curricula to promote students’ academic success. As a result, their instructional choices more often privileged linguistic varieties aligned with White Anglo-Saxon norms—the curriculum. Consequently, rather than employing asset-based teaching, they asked Black English speakers to “erase” their Black English use to better meet the expectations of school. This often looked like writing and speaking Mainstream American English rather than Black English. Therefore, teachers’ instructional choices often resulted in deficit thinking results, which notices a cultural mismatch but upholds dominant culture while viewing cultural differences as unsuitable for the setting. Study findings suggest implications for curriculum designers and teachers to create spaces for Black students in the curriculum and classroom to fully see, hear, and represent themselves to take advantage of opportunities to fully be present in their education experience. Future research recommendations include exploration of the role and influence of professional development, curriculum redesign, and teachers’ choices on Black English speakers’ self-development and identity.