Improving the predictability of time series by chaotic parameter estimation

Limited literature regarding parameter estimation of dynamic systems has been identified as the central-most reason for not having parametric bounds in chaotic time series. However, literature suggests that a chaotic system displays a sensitive dependence on initial conditions, and our study reveals that the behavior of chaotic system: is also sensitive to changes in parameter values. Therefore, parameter estimation technique could make it possible to establish parametric bounds on a nonlinear dynamic system underlying a given time series, which in turn can improve predictability. By extracting the relationship between parametric bounds and predictability, we implemented chaos-based models for improving prediction in time series. ^ This study describes work done to establish bounds on a set of unknown parameters. Our research results reveal that by establishing parametric bounds, it is possible to improve the predictability of any time series, although the dynamics or the mathematical model of that series is not known apriori. In our attempt to improve the predictability of various time series, we have established the bounds for a set of unknown parameters. These are: (i) the embedding dimension to unfold a set of observation in the phase space, (ii) the time delay to use for a series, (iii) the number of neighborhood points to use for avoiding detection of false neighborhood and, (iv) the local polynomial to build numerical interpolation functions from one region to another. Using these bounds, we are able to get better predictability in chaotic time series than previously reported. In addition, the developments of this dissertation can establish a theoretical framework to investigate predictability in time series from the system-dynamics point of view. ^ In closing, our procedure significantly reduces the computer resource usage, as the search method is refined and efficient. Finally, the uniqueness of our method lies in its ability to extract chaotic dynamics inherent in non-linear time series by observing its values. ^

The experiences of Cuban American women attending a Hispanic serving institution and the influences on identity development

The purpose of this study was to gain an understanding and gather insight into the experiences of Cuban American women attending a 4-year, public, Hispanic Serving Institution and how those experiences influenced their identity development. This was accomplished by conducting in-depth interviews and focus groups with 12 self-identified Cuban American women who were classified as sophomores, juniors, seniors, or graduate students. All of the participants had attended Florida International University for at least 1 year. The women had varying degrees of on and off campus academic and campus involvement activities. Participants were asked about six topics: (a) family, (b) cultural influences, (c) gender, (d) ethical and moral development, (e) education, and (f) ethnic identity. Based on the coding of the data provided by the participants, several interconnected themes emerged including the importance of family, familial support, cultural pride, expected gender roles, core values, decision making, biculturalism, and the value of attending a Hispanic Serving Institution. These themes were found to be all related to the identity development of the participants. It was found that looking at identity through a multidimensional lens is essential. Looking at personal growth and development through anthropological, sociological, and psychosocial lenses gave greater insight to a population of students who have been largely underrepresented in the literature. The findings of this case study are that culture is contextual and identity development is complex for first and second generation Cuban American women attending a Hispanic Serving Institution in a majority minority city. It was found that several factors, including the importance of family and gender roles, were not found to be more important than one another; rather they supported each other in regards to the participants' identity development. The notion of biculturalism as it has been presented in the literature was challenged in this study as it was found that the participants' experiences living and attending a school in a majority minority city presented a new way of understanding what it might mean to be bicultural. For professionals in the field, the findings of this study may lead to a broader understanding of nuances within the Hispanic community and a better understanding of the distinctiveness of what it means to be a Cuban American woman.

Stereotype threat and the standardized testing experiences of African American children at an urban elementary school

Stereotype threat (Steele & Aronson, 1995) refers to the risk of confirming a negative stereotype about one’s group in a particular performance domain. The theory assumes that performance in the stereotyped domain is most negatively affected when individuals are more highly identified with the domain in question. As federal law has increased the importance of standardized testing at the elementary level, it can be reasonably hypothesized that the standardized test performance of African American children will be depressed when they are aware of negative societal stereotypes about the academic competence of African Americans. This sequential mixed-methods study investigated whether the standardized testing experiences of African American children in an urban elementary school are related to their level of stereotype awareness. The quantitative phase utilized data from 198 African American children at an urban elementary school. Both ex-post facto and experimental designs were employed. Experimental conditions were diagnostic and non-diagnostic testing experiences. The qualitative phase utilized data from a series of six focus group interviews conducted with a purposefully selected group of 4 African American children. The interview data were supplemented with data from 30 hours of classroom observations. Quantitative findings indicated that the stereotype threat condition evoked by diagnostic testing depresses the reading test performance of stereotype-aware African American children (F[1, 194] = 2.21, p < .01). This was particularly true of students who are most highly domain-identified with reading (F[1, 91] = 19.18, p < .01). Moreover, findings indicated that only stereotype-aware African American children who were highly domain-identified were more likely to experience anxiety in the diagnostic condition (F[1, 91] = 5.97, p < .025). Qualitative findings revealed 4 themes regarding how African American children perceive and experience the factors related to stereotype threat: (1) a narrow perception of education as strictly test preparation, (2) feelings of stress and anxiety related to the state test, (3) concern with what “others” think (racial salience), and (4) stereotypes. A new conceptual model for stereotype threat is presented, and future directions including implications for practice and policy are discussed.

Engagement experiences of Hispanic Generation 1.5 English language learners at a Massachusetts community college

Hispanic Generation 1.5 students are foreign-born, U.S. high school graduates who are socialized in the English dominant K-12 school system while still maintaining the native language and culture at home (Allison, 2006; Blumenthal, 2002; Harklau, Siegal, & Losey, 1999; Rumbault & Ima, 1988). When transitioning from high school to college, these students sometimes assess into ESL courses based on their English language abilities, and because of this ESL placement, Hispanic Generation 1.5 students might have different engagement experiences than their mainstream peers. Engagement is a critical factor in student success and long-term retention because students’ positive and negative engagement experiences affect their membership and sense of belonging at the institution. The purpose of this study was to describe the engagement and membership experiences of Hispanic Generation 1.5 students’ at a Massachusetts community college. This study employed naturalistic inquiry within an embedded descriptive case study design that included three units of analysis: the students’ engagement experiences in (a) ESL courses, (b) developmental courses, and (c) mainstream courses. The main source of data was in-depth interviews with Hispanic Generation 1.5 students at Commonwealth of Massachusetts Community College. Criterion sampling was used to select the interview participants, ensuring that all participants were native Spanish speakers and were taking or had taken at least one ESL course at the institution. The study findings show that these Hispanic Generation 1.5 students at the college did not perceive peer engagement as critical to academic success. Most times the participants avoided peer engagement outside of the classroom, especially with fellow Hispanic students, who they felt would deter them from their English language development and general academic work. Engagement with ESL faculty and ESL academic support staff played the most critical role in the participants’ sense of belonging and success, and students who were required to engage with faculty and academic support staff outside of the classroom were the most satisfied with their educational experiences. While the participants were all disappointed with some aspect of their ESL placement, they valued the ESL engagement experiences more than the engagement experiences while completing developmental and credit coursework.

Mentoring Experiences of Indo-Caribbean Immigrants in the United States

This research explored perceptions of Indo-Caribbean protégés in cross-cultural mentoring experiences with White, Black, Black Cherokee, Indian and Hispanic mentors. Environmental forces, mentor influences, and knowledge sharing shaped these relationships. This research implies that mentors’ and protégés’ understanding of each others’ values, beliefs, and attitudes enhance outcomes of the relationship.

Two Educators’ Experiences of Double Dose Reading Classes

The purpose of this qualitative study was to gain knowledge of the phenomenon of double dose reading classes. A reading coach and a reading teacher were interviewed. Data revealed teachers navigate a complicated set of negotiations in order to deliver quality instruction while simultaneously satisfying mandated requirements from supervisors.

The Lived Experiences of African American Males in an Urban University Setting

The purpose of this phenomenological study was to explore lived experiences of African American males who have advanced into higher education. The goal of the study was to identify reasons African American males attend college so higher education institutions can work toward increasing the number of African American males in higher education.

A comprehensive assessment of self -report experiences of adoptive parents of special needs children in Florida

Adoption of special needs children is now seen as a life long event whereby the adoptive child and family have unique needs. The need for postplacement resources throughout the life cycle of the adoption process is evident. This exploratory-descriptive research employed a random stratified cross-sectional design. The purpose of the study was to describe, identify, examine, and assess the relative influence of identified empirically and conceptually relevant variables of self-report experiences of adoptive parents of special needs children. Primary areas of exploration included: (1) adoptive children and families' characteristics, (2) postplacement service needs, utilization and satisfaction, and (3) adoptive parents' perceptions of their adoption experiences. A proportionate stratified random mail survey was used to obtain 474 families who had adopted special needs children from the 15 geographic districts which make up the state adoption social service agency in Florida. A 144-item survey questionnaire was used to collect basic information on demographic data, service provision, and adoption experiences. Four research questions were analyzed to test the effect the predictor variables had on willingness to adopt another special needs child, successful adoption, satisfying experience, and realism about problems. All four research questions revealed that the full model and the child's antecedent and the adoptive parents' intervening variable blocks were significant in explaining the variance in the dependent variables. The child's intervening variables alone were only significant in explaining the variance for one of the dependent variables. The results of the statistical analysis on the fifth research question and the three hypotheses determined that (1) only one postplacement service, crisis intervention, had a statistically significant impact on the adoptive parents' perceived level of satisfaction with the adoption experience; (2) adoptive parents who rate their adoption as successful are more likely to express a desire to adopt another special needs child; (3) the more adequate information on the child the adoptive parents perceived that they had prior to placement, the more they perceived they were realistic about the problems they would encounter; and (4) six specific postplacement services were found to be significant in predicting successful adoptions--crisis intervention, outpatient drug/alcohol treatment, maintenance subsidy, physical therapy, special medical equipment, and family counseling. Implications for the social work field and future research are discussed. ^

The Next Generation of Scientists: Examining the Experiences of Graduate Students in Network-Level Social-Ecological Science

By integrating the research and resources of hundreds of scientists from dozens of institutions, network-level science is fast becoming one scientific model of choice to address complex problems. In the pursuit to confront pressing environmental issues such as climate change, many scientists, practitioners, policy makers, and institutions are promoting network-level research that integrates the social and ecological sciences. To understand how this scientific trend is unfolding among rising scientists, we examined how graduate students experienced one such emergent social-ecological research initiative, Integrated Science for Society and Environment, within the large-scale, geographically distributed Long Term Ecological Research (LTER) Network. Through workshops, surveys, and interviews, we found that graduate students faced challenges in how they conceptualized and practiced social-ecological research within the LTER Network. We have presented these conceptual challenges at three scales: the individual/project, the LTER site, and the LTER Network. The level of student engagement with and knowledge of the LTER Network was varied, and students faced different institutional, cultural, and logistic barriers to practicing social-ecological research. These types of challenges are unlikely to be unique to LTER graduate students; thus, our findings are relevant to other scientific networks implementing new social-ecological research initiatives.

Perceptions and experiences of intimate partner violence among Hispanic college students

Intimate partner violence (IPV) is recognized as a serious, growing problem on college campuses. IPV rates among college students exceed estimates reported for the general population. Few studies have examined the impact of IPV among the Hispanic college student (HCS) population or explored how HCSs perceive and experience IPV. Focusing on young adults (ages 18 to 25 years), this mixed methods study was designed to explore the perceptions and experiences of IPV focusing on levels of victimization and perpetration in relation to gender role attitudes and beliefs, exposure to parental IPV, acculturation, and religiosity. A sample of 120 HCSs was recruited from two south Florida universities. A subsample of 20 participants was randomly selected to provide qualitative responses. All participants completed a series of questionnaires including a demographic survey, the FPB, CTS2-CA, SASH, ERS and CTS2. Bivariate correlational techniques and multiple regressions were used to analyze data. Marked discrepancy between participants' perceived experience of IPV (N = 120) and their CTS2 responses (n = 116, 96.7%). Only 5% of the participants saw themselves as victims or perpetrators of IPV, yet 66% were victims or 67% were perpetrators of verbal aggression; and 31% were victims or 32.5% were perpetrators of sexual coercion based on their CTS2 scores. Qualitative responses elicited from the subsample of 20 students provided some insight regarding this disparity. There was rejection of traditional stratified gender roles. Few participants indicated that they were religious (20.8%, n = 25). Evidence for the theory of intergenerational transmission of violence was noted. Recall of parental IPV was a significant predictor of level of IPV victimization (β = 0.177, SE = 0.85, p = 0.041). Nursing and social service providers must be cognizant that contributing factors to either victimization and/or perpetration of IPV among college students must be addressed first (i.e., perceptions of IPV), both in acute (i.e., emergency department) and community (i.e., college and university) settings for optimum intervention outcome.

An investigation into the lived experiences of racism among African -American nurses

The purpose of this study was to investigate the lived experience of racism among African-American nurses. Utilizing a qualitative phenomenological approach, data were collected by interviewing 10 African-American nurses currently practicing in Dade county. The interviews were tape recorded and transcribed verbatim. Data were analyzed using the seven step method of Colaizzi (1978). The findings of this study indicate that racism encompasses attitudes and beliefs which generate behaviors reflecting ethnocentric ideations. The process of racism creates glass ceilings that hinder the career advancement of African-American nurses. Internalizing these experiences of racism engenders feelings of betrayal and erodes unity and cohesion within the group. This study points out the need to openly confront racism in the nursing profession, from the classroom to the workplace.

The Fullness of time

THE FULLNESS OF TIME is a novel about the quest for identity that transcends the limitations of moral duty, social status, and cultural conventions. Set in Tarpon Springs, Florida, in 1969, it is the story of Victor Lucas, a young Greek immigrant forced to go to war in Vietnam in another man's place in order to save the woman he loves. He must survive the war to return and reclaim his love and his rightful place in society. Based on the archetypal hero's quest as articulated by Joseph Campbell, the narrative is told from the limited third-person perspective of the main character. Though the journey is particular to Tarpon Springs in the 1960s, it echoes the human struggle and triumph in the wanderings of Ulysses. The novel's influences include Thomas Hardy's The Mayor of Casterbridge, but is also thematically related to contemporary works exploring cultural turbulence and upheaval.

A Basic Interpretive Study of the Experiences of University Students Who Have Dropped or Failed an Online Course

Online courses have increased in enrollments over the past few decades. As the number of students taking online courses have increased, so has the number of students who have dropped or failed an online course. According to the literature, online courses may have higher drop rates than traditional, face-to-face courses. The number of students who fail an online course is, also, of concern. As online courses may continue to grow over the next few decades, studies on persistence in online courses may benefit students, administrators, instructional designers, educators, and researchers. Although previous research studies have addressed persistence in online courses, very few examine it from the perspectives of students who were unsuccessful in their courses. These students may have unique insights about the online experience that may have related to their lack of success. The purpose of this study was to understand the experiences of university students who have failed or dropped an online course through the lenses of transactional distance theory and Kember’s model of dropout in distance education. Transactional distance theory discusses the dialog, structure, and learner autonomy involved in an online course, while, Kember’s model presents categories that may relate to dropping an online course. Together, the theory and model may help in understanding the experiences of students who have dropped or failed an online course. In this study, semi-structured interviews were conducted with 20 participants from a large Southeastern university in the United States. Based on the participants’ responses, the data was sorted and ranked according to the amount of transactional distance in their courses, as well as the categories of Kember’s model. Many of the participants who experienced low or high transactional distance have, also, expressed an issue with the goal commitment category of Kember’s model. Additionally, there were important differences in the student characteristics of those who dropped or failed an online course. Furthermore, suggestions for improving online courses were given by the participants. Some of these suggestions included more student-instructor interactions, the use of more technology tools in their online course, and for orientations to the online environment to be offered.

Stereotype Threat and the Standardized Testing Experiences of African American Children at an Urban Elementary School

Stereotype threat (Steele & Aronson, 1995) refers to the risk of confirming a negative stereotype about one’s group in a particular performance domain. The theory assumes that performance in the stereotyped domain is most negatively affected when individuals are more highly identified with the domain in question. As federal law has increased the importance of standardized testing at the elementary level, it can be reasonably hypothesized that the standardized test performance of African American children will be depressed when they are aware of negative societal stereotypes about the academic competence of African Americans. This sequential mixed-methods study investigated whether the standardized testing experiences of African American children in an urban elementary school are related to their level of stereotype awareness. The quantitative phase utilized data from 198 African American children at an urban elementary school. Both ex-post facto and experimental designs were employed. Experimental conditions were diagnostic and non-diagnostic testing experiences. The qualitative phase utilized data from a series of six focus group interviews conducted with a purposefully selected group of 4 African American children. The interview data were supplemented with data from 30 hours of classroom observations. Quantitative findings indicated that the stereotype threat condition evoked by diagnostic testing depresses the reading test performance of stereotype-aware African American children (F[1, 194] = 2.21, p < .01). This was particularly true of students who are most highly domain-identified with reading (F[1, 91] = 19.18, p < .01). Moreover, findings indicated that only stereotype-aware African American children who were highly domain-identified were more likely to experience anxiety in the diagnostic condition (F[1, 91] = 5.97, p < .025). Qualitative findings revealed 4 themes regarding how African American children perceive and experience the factors related to stereotype threat: (1) a narrow perception of education as strictly test preparation, (2) feelings of stress and anxiety related to the state test, (3) concern with what “others” think (racial salience), and (4) stereotypes. A new conceptual model for stereotype threat is presented, and future directions including implications for practice and policy are discussed.