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Performance of random walks and sampling for graph search
No full textThis thesis discusses several random walk and sampling algorithms and analyses the expected cost of using these algorithms to find target nodes in large graphs. The first algorithms discussed are degree biased random walks. A degree biased random walk variant is introduced entitled Self Avoiding Walk Jump (SAWJ). The innovation is in roughly upper bounding the expected unit cost for SAWJ to find a maximum degree node using a discrete time Markov chain model. Second this thesis estimates the expected unit and linear cost to find a target node in Erdos Renyi (ER) graphs under three variants of star sampling, where a random node is selected and it and its neighbors are sampled. These estimates are shown numerically to be accurate on ER and some real-world graphs. Third this thesis looks at questions tangentially related to analyzing graph search algorithms. Counter examples are given showing greedy wiring or rewiring algorithms do not necessarily construct maximally assortative simple graphs and an estimate is given of the expected samples to find a near maximum value in a set of elements with known distribution but unknown parameterization.Ph.D., Electrical Engineering -- Drexel University, 201
Mixed Reality Interiors: Exploring Augmented Reality Immersive Space Planning Design Archetypes for the Creation of Interior Spatial Volume 3D User Interfaces
Get PDFAugmented reality is an increasingly relevant medium of interaction and media reception with the advances in user worn or hand-held input/output technologies endowing perception of the digital nested within and reactive to the native physical. Our interior spaces are becoming the media interface and this emergence affords designers the opportunity to delve further into crafting an aesthetics for the medium. Beyond having the virtual assets and applications in correct registration with the real-world environment, critical topics are addressed such as the compositional roles of virtual and physical design features including their purpose, modulation, interaction potentials and implementation into varying indoor settings. Examining and formulating methodologies for mixed reality interior 3D UI schemes derived from the convergence of digital media and interior design disciplines comprise the scope of this design research endeavor. A holistic approach is investigated to produce a framework for augmented reality 3D user interface interiors through research and development of pattern language systems for the balanced blending of complimentary digital and physical design elements. These foundational attributes serve in the creation, organization and exploration of interactive possibilities and implications of these hybrid futuristic spatial interface layouts.M.S., Digital Media -- Drexel University, 201
Effectiveness of Coastal Green Infrastructure Under Compound Events Due to Climate Change
No full textGreen Infrastructure (GI) has become an increasingly prevalent method of supplementing grey infrastructure to manage stormwater. Most GI uses infiltration into the soil as a method of stormwater management and therefore the facilities are generally built with a setback from the coast line due to fear of lack of infiltration into saturated soils in high water tables. This paper analyzes a constructed wetland built in Flushing, New York that was built on the shoreline of Meadow Lake and its performance in stormwater retention. The wetland has been monitored for three seasons and the observed data points were used to calibrate a hydrologic model of the system. The model predicts that for Scenario 1, 42%, 67% and 44% of stormwater was retained in each respective reason, proving the site to be valuable for the area. The model was then subject to two different climate change scenarios that include (1) higher evapotranspiration and higher precipitation, and (2) sea level rise in Meadow Lake that would affect the wetland. Scenario 2 proved that up to 90% of stormwater was managed by the wetland but Scenario 3 showed that as low as 18% was managed. Finally, Scenario 4 managed 87% of stormwater. While this analysis proves to be beneficial to manage stormwater, there may be other ecological effects that were beyond the scope of this research.M.S., Civil Engineering -- Drexel University, 201
Exploring the Experiences of Enlisted Active Duty Soldiers in Obtaining Their Initial College Degree: A Basic Qualitative Study
Get PDFDespite access to institutions of higher learning and readily available funding to attend them, only 12% of U.S. Army Enlisted Soldiers possess any type of college degree. This study identified the factors that provided the greatest challenges to Enlisted Soldiers in attempting to complete an initial college degree. This study utilized interviews as a primary means of data collection as part of a basic qualitative methodology designed to capture the lived experiences of 12 research participants. The research questions used were: (a) What programs in academia and the military do active duty Enlisted Soldiers believe are available to assist them in the completion of an initial degree? (b) What has motivated active duty Enlisted Solders to enroll in degree programs (c) What is the essence of the experiences of active duty Enlisted Soldiers who have considered or attempted a degree during their enlistment? Following in-depth interviews with each of the 12 participants, descriptive and pattern coding were conducted to analyze the results. Relevant literature related to the study was also taken into account when analyzing the findings. Five interpreted results emerged: (a) preparation for transition into civilian life figures prominently as a motive and right to take college courses; (b) experiences and opportunities with civilian education vary greatly due to variables that include dynamic locations, career fields, duty positions, and stages of career; (c) fundamental knowledge of how college works is critical to student success, but often absent; (d) length of time in service enhances the likelihood of course and degree completion; and (d) failure to take full advantage of college opportunities on active duty remains an emotive experience for many. Recommendations resulting from this study that may increase the likelihood of Enlisted Soldiers' success as college students and included: (a) develop greater communication among commands, education centers, and institutions of higher learning that serve Enlisted Soldiers; (b) develop better communication between various local institutions of higher education at individual duty locations to provide opportunities for sharing best practices and streamline the accumulation of credit hours between those schools; (c) assess the possibility of limiting, consolidating, or establishing preferences for degree programs in order to more easily clarify options for Enlisted Soldiers. Keywords: military civilian education, tuition assistance, military outreach, non-traditional student motivation, adult student motivation, basic qualitative study.Ed.D., Educational Leadership and Management -- Drexel University, 201
Exploring Parents' Engagement with a Digital Personalized Learning System: A Case Study in an Urban Elementary School
No full textNational data cited by Barton & Coley (2010) indicate that African American males are achieving less than Caucasian males in elementary school-level reading. Taking education beyond the classroom and into the home may be a critically important mechanism for addressing this problem and reducing the negative impact of academic contexts where African American males are experiencing deficiencies in reading. Research by Renth, Buckley, & Puchner (2015) shows parent engagement plays a crucial role in students' academic success in school. However, not all parents are equipped with appropriate instructional tools to promote academic engagement within the home. Beecher & Sweeny (2008) noted that various instructional practices such as enrichment, differentiated instruction, and culturally relevant instruction can positively affect educational disparities in African American males. Their research employed a case study design to better understand parents' engagement with a digital personalized learning system and its influence on their African American boys' reading scores in an urban elementary school. The three literature review streams of the present study included educational disparities, parent engagement, and technology-based learning. Findings suggest that parents perceive Lexia as easily accessible and tailored to the individual learning needs of their child. Parents also reported noticeable improvements in the areas of comprehension and spelling. Furthermore, parents expressed a desire for additional digital learning resources to support academic engagement with their child.Ed.D., Education -- Drexel University, 201
Examining Staff Development: An Assessment of Healthcare Staff Perception of Employee Development Within a Healthcare Facility Located in Southeast Pennsylvania
No full textDeveloping human capita within healthcare facilities has been a continuous anxiety for the Talent Management of healthcare facility Human Resource Department. Utilizing efficient talent management strategies is critical to producing a culture for current and future success. Healthcare facilities are equipped with machinery that would incur a towering economic endowment for the best care of its patients. However, the best investment an organization can make is in the value of its employees. This research study illuminates the perceptions of the talent management process of health care professionals within a hospital organization. The study examines the hiring process, workforce development, and succession planning of a southeastern Pennsylvania healthcare facility. Healthcare organizations have the challenge of developing individuals in a diverse generational workforce economy. Organizations identify there is a current generational gap that serves as a catalyst for employee engagement that would lead to cultivating workforce skill sets. The qualitative method aided in answering the central question; - How does a health care organization in eastern Pennsylvania prepare for successfully addressing the hiring process, the current workforce development plan, and succession planning? The findings, results, and conclusion reveal that the organization relies on its employee culture to manifest strategies for implementation for the hiring process, workforce development, and succession planning.Ed.D., Educational Leadership and Management -- Drexel University, 201
A Fundamental Study of Water Transport in Epoxy/Amine Crosslinked Polymers
No full textEpoxy/amine crosslinked polymers have been historically employed as binders in surface coatings due to their excellent adhesion to high energy surfaces like steel, and aluminium., their good thermal and mechanical properties, and good barrier properties. While there has been a significant effort and relatively large pool of literature on structure to property relationships, such as modulus (E') and glass transition temperature (Tg), for epoxy/amine crosslinked polymers, there is not a good fundamental understanding of how epoxy/amine crosslinking composition correlates to water barrier properties such as solubility of water (S), the diffusivity of water (D), and overall permeability of water (P). Furthermore, a generalized correlation between epoxy/amine crosslinking composition and their water transport properties has not been reported. This study focuses on developing a fundamental relationship between the crosslinking composition of epoxy/amine crosslinked polymers to their water barrier properties and how these properties affect their performance in anti-corrosion coatings. This is done by creating and testing model epoxy/amine polymers and modifying these by adding hydrophobic segments pendant to the network, within the polymer backbone, and as a secondary phase. The concentration of atomic oxygen in the epoxy/amine crosslinked polymers ([O], mol/cc) was found to be the governing parameter for S. The diffusivity to water was also found to be correlated to [O] within sample sets, however, a master curve for D as a function of [O] was not observed. The density (ρ) and the glassy modulus (EG) of epoxy/amine polymers was found to be weakly correlated and inversely proportional to D. An examination of P - the product of S and D - of all epoxy/amine crosslinked polymers studied showcases the challenge remaining in linking physical and structural properties to P - and D. A major finding in this work is the reduction of both S and D with the addition of a hydrophobic chain extender. Design guidelines for tuning S and D in epoxy/amine crosslinked polymers will be shown and may pave the way to new effective and environmentally benign corrosion control.Ph.D., Chemical Engineering -- Drexel University, 201
The Natural History of Marijuana Use Among Young Adult Medical Marijuana Patients in Los Angeles: From Initiation to Current Use
No full textBackground: The legalization of medical marijuana in California in 1996 was a step towards providing more medical alternatives to individuals with chronic health conditions. Since then, studies have focused primarily on the medicinal benefits of marijuana and/or patient characteristics among adults, but focused less on young adults who might be most vulnerable to the effects of marijuana use and are among the most impacted by legislative changes regarding access to marijuana. Specifically, limited data exist on health histories of young adult medical marijuana patients, their motives and patterns of marijuana use before and after getting a doctor's recommendation and the role of medical marijuana dispensaries on their motives and use behaviors. Methods: A total of 40 young adults (aged 18 to 26), who had a valid doctor's recommendation for medical marijuana use, were recruited in Los Angeles to complete a quantitative survey as well as a semi-structured qualitative interview in 2014-15. Study participants were asked about health histories, their motivations for marijuana use before and after obtaining recommendation, how their health condition was linked to marijuana use, and their perception on medical marijuana dispensaries. Simple descriptive analysis was utilized to present frequency results from the quantitative survey. A qualitative thematic analysis was used to analyze transcripts and results present the main themes extracted from the interviews. In addition, geospatial analysis was applied to assess the accessibility of dispensaries. Results: Initial reasons to use marijuana were not linked up to participants' health histories even though all experienced one or more medical conditions in their teenage and/or young adulthood period. The majority of the participants discovered the medicinal benefits of marijuana either before or after becoming a medical marijuana patient and a minority of them continued using marijuana largely for recreational purposes. For a majority of participants, early health histories and motivations for use linked up the reason reported to the doctor for getting the recommendation. Participants' marijuana use increased during the early phase after obtaining a medical marijuana recommendation. After a while, a majority found a balance between their marijuana use and life responsibilities. Medical marijuana dispensaries reported by the participants can be roughly categorized into two types: professional and transactional. Professional dispensaries offered quality customer service. Dispensaries were spread across almost all parts of Los Angeles but participants were generally willing to travel a long distance to reach their primary dispensary of choice. Conclusions: Young adult medical marijuana patients experienced various health conditions in their teenage and/or young adulthood period. For a majority, their health condition served as a strong motivating factor to continue to use marijuana and ultimately, to seek a doctor's recommendation for medical marijuana. Legal access to marijuana resulted in more marijuana use. After a while, marijuana use stabilized in accordance with their life responsibilities. Results also suggest the importance of professional medical marijuana dispensaries in educating patients.Dr.P.H., Community Health and Prevention -- Drexel University, 201
Beyond Lifestyle Factors: Exploring The Role of The Social Determinants of Health in Weight Loss Attempts in People with Serious Mental Illness Living in Supportive Housings Settings
No full textBackground: People with serious mental illness (SMI) experience marked health disparities from preventable and treatable conditions and a prevalence of overweight/obesity almost twice the general US population. The problems and proposed solutions to obesity-related morbidity in people with SMI have mainly focused on the individual level. Difficulties with healthy eating and physical activity are attributed to behavior or lifestyle factors, such as poor diet, sedentary routines, and low motivation, as well as increasing use of second generation antipsychotic medications. Larger system level factors have received limited attention in the response to this epidemic and past research has not adequately involved people with SMI in a deeper exploration of these issues. Health disparities involving the problem of obesity in people with SMI have not been considered using a human rights framework. Methods: This dissertation used a participatory action orientation with a mixed-methods sequential explanatory model to explore the healthy equity factors that facilitate or limit clinically significant weight loss in people with SMI who are overweight or obese and participating in a 12-month, peer-led, group healthy lifestyle intervention. Study one utilized baseline data of 93 participants in the intervention arm of the parent Peer Group Lifestyle Balance study. Quantitative analysis was used to explore associations between the predictor variable of food security at baseline and the outcome variable of 6-month weight change. Studies two and three were developed through a participatory Photovoice project with 8 participant co-researchers. Study two explored the lived experience of healthy eating and physical activity through 7 weekly sessions with the co-researchers consisting of individual photo-elicitation and group discussion of photos and captions. Study three explored the co-researchers experience of presenting at four varied community events. Results: The results of the quantitative analysis revealed that 76.2% percent of the sample reported some level of food insecurity, 22.6% with marginal food security, 28.6% with low food security, and 25.0% with very low food security. The mean weight change at 6 months was -2.86 pounds (SD = 13.67) with a range of -47.6 to 33.0. At six months, 65% of the total sample had a weight lower than their baseline weight. The association between metformin use and diagnosis of diabetes with weight change was significant with the metformin group losing a mean of 6.7lbs vs 0.3lbs in intervention participants not taking metformin. The analysis of the main effect for baseline food security on weight change between baseline and 6 months approached significance (F (2, 81) = 3.075, p =.052, partial η2 = .071). In the Photovoice project, the eight co-researchers selected a total of 33 photos and captions to represent their experience and organized the photos into five themes: 1) Corner stores in our neighborhood, 2) Challenges to healthy eating and exercise, 3) Healthy eating ideas with limited supplies, 4) Exercise: Challenges and options, and 5) Recovery: Body, mind, and spirit. The themes from the photographs reflected two overarching themes: structural barriers and overcoming structural barriers. Four overlapping themes emerged from the analysis of the post-advocacy presentations: 1) Empowerment, 2) Influence, 3) Barriers to participation, and 4) The system. Conclusion: The strengths of this study are grounded in the mixed-methods exploration of the impact of the social determinants of health on healthy eating and physical activity in a highly marginalized population with significant health disparities resulting in part from obesity-related conditions. The human rights framework provides an organizing lens to understand the findings of this study. The qualitative findings provided concrete explanations of the quantitative findings. The Adult Food Security Survey revealed a 76% rate of any level of food insecurity in the sample. Fifty-four percent of the sample reported low or very low food security, higher than the national average of 12.3% (United States Department of Agriculture, 2015). The main effect of food security on 6-month weight change approached significance. Documenting this rate of food insecurity in the population is a critical finding and suggests many people with SMI are not achieving the right to food, despite living in supportive housing settings and receiving Supplemental Nutrition Assistance Program (SNAP) benefits. The reasons for this inequality are complex and the Photovoice project described in Chapter 3 provides some insights into this situation from the population itself. The high cost of poor quality food available in urban corner stores and fast food establishments as well as the cost of transportation out of the neighborhood contribute directly to food insecurity. The use of food pantries, with variable food quality is a consequence of food insecurity and limited SNAP benefits in the population. These situations are a threat not just to the right to healthy food, but the right to health itself. The easy availability of tobacco and alcohol products through neighborhood convenience stores, the lack of safe places to exercise, and increased rates of violence seriously impede opportunities to live a healthy life. The qualitative findings were also useful in expanding not only our understanding of the problem, but the strengths of the populations, and potential real-world solutions. Multiple level factors are making a positive contribution to the rights of people with psychiatric disabilities. The quantitative analysis showed that 65% of the total sample had lost weight in the first 6 months of participation in the project. Co-researchers in the Photovoice project reported many examples of knowledge and skills they had learned or improved through participation in the PGLB study. These skills, which were taught and modeled by specially trained peer specialists, were used to overcome structural barriers to healthy eating and physical activity, and likely contributed to weight loss. Co-researchers in the advocacy sessions of the project discussed experiences of segregation, stigma, distrust, and indignity arising from a system that does not always respect the rights of people with psychiatric disabilities. Most people with SMI have experienced significant past social traumas that contribute to, or arise from, their experience of psychiatric disability. Nevertheless, the co-researchers in this project displayed and articulated a sense of empowerment and pride in raising awareness of their experiences and being heard by stakeholders, advocates, and peers during their presentations. These experiences provide evidence that multiple groups in public health and local government are interested in and committed to the rights of people with disabilities.Dr.P.H., Community Health and Prevention -- Drexel University, 201
Effects of Production Pressure on CRNA Practice and Patient Safety
No full textProduction pressure is often discussed in the anesthetic community with regards to its effects on patient safety, but has been rarely scrutinized. The purpose of this project was to examine the primary sources of production pressure and how they relate to patient safety in the practice of the Certified Registered Nurse Anesthetist (CRNA). This quality improvement project surveyed 2000 CRNA’s via email to assess the phenomenon and its impact on safety. There were 239 total responses with 17 incomplete surveys that were not used in the statistical analysis. Questions asked related to the sources of production pressure, communication, and errors caused by production pressures as well as basic demographic information. In this survey, it was determined that the phenomenon of production pressure has a significant impact on CRNA practice and safety. The production pressures relating to on time starts, turnover time, working hours and staffing levels were perceived by CRNAs to have the most significant effects on their practice. It is apparent that a culture of deviance continues to overshadow the culture of safety given the fact that greater than 55% of CRNAs witnessed errors due to production pressures with the potential to harm patients and 27% self-reported making those errors. The effects of production pressure on CRNA practice and safety are of significant concern and need to be reduced. The balance between safe, patient centered care and cost effectiveness needs to be constantly reevaluated.D.N.P., Nursing Practice -- Drexel University, 201