26 resultados para reliability and validity
em Digital Commons at Florida International University
Resumo:
There is a growing body of literature that provides evidence for the efficacy of positive youth development programs in general and preliminary empirical support for the efficacy of the Changing Lives Program (CLP) in particular. This dissertation sought to extend previous efforts to develop and preliminarily examine the Transformative Goal Attainment Scale (TGAS) as a measure of participant empowerment in the promotion of positive development. Consistent with recent advances in the use of qualitative research methods, this dissertation sought to further investigate the utility of Relational Data Analysis (RDA) for providing categorizations of qualitative open-ended response data. In particular, a qualitative index of Transformative Goals, TG, was developed to complement the previously developed quantitative index of Transformative Goal Attainment (TGA), and RDA procedures for calculating reliability and content validity were refined. Second, as a Stage I pilot/feasibility study this study preliminarily examined the potentially mediating role of empowerment, as indexed by the TGAS, in the promotion of positive development. ^ Fifty-seven participants took part in this study, forty CLP intervention participants and seventeen control condition participants. All 57 participants were administered the study's measures just prior to and just following the fall 2003 semester. This study thus used a short-term longitudinal quasi-experimental research design with a comparison control group. ^ RDA procedures were refined and applied to the categorization of open-ended response data regarding participants' transformative goals (TG) and future possible selves (PSQ-QE). These analyses revealed relatively strong, indirect evidence for the construct validity of the categories as well as their theoretically meaningful structural organization, thereby providing sufficient support for the utility of RDA procedures in the categorization of qualitative open-ended response data. ^ In addition, transformative goals (TG) and future possible selves (PSQ-QE), and the quantitative index of perceived goal attainment (TGA) were evaluated as potential mediators of positive development by testing their relationships to other indices of positive intervention outcome within a four-step method involving both analysis of variance (ANOVA and RMANOVAs) and regression analysis. Though more limited in scope than the efforts at the development and refinement of the measures of these mediators, the results were also promising. ^
Resumo:
The dissertation reports on two studies. The purpose of Study I was to develop and evaluate a measure of cognitive competence (the Critical Problem Solving Skills Scale – Qualitative Extension) using Relational Data Analysis (RDA) with a multi-ethnic, adolescent sample. My study builds on previous work that has been conducted to provide evidence for the reliability and validity of the RDA framework in evaluating youth development programs (Kurtines et al., 2008). Inter-coder percent agreement among the TOC and TCC coders for each of the category levels was moderate to high, with a range of .76 to .94. The Fleiss' kappa across all category levels was from substantial agreement to almost perfect agreement, with a range of .72 to .91. The correlation between the TOC and the TCC demonstrated medium to high correlation, with a range of r(40)=.68, p<.001 to r(40)=.79, p<.001. Study II reports an investigation of a positive youth development program using an Outcome Mediation Cascade (OMC) evaluation model, an integrated model for evaluating the empirical intersection between intervention and developmental processes. The Changing Lives Program (CLP) is a community supported positive youth development intervention implemented in a practice setting as a selective/indicated program for multi-ethnic, multi-problem at risk youth in urban alternative high schools in the Miami Dade County Public Schools (M-DCPS). The 259 participants for this study were drawn from the CLP's archival data file. The study used a structural equation modeling approach to construct and evaluate the hypothesized model. Findings indicated that the hypothesized model fit the data (χ2 (7) = 5.651, p = .83; RMSEA = .00; CFI = 1.00; WRMR = .319). My study built on previous research using the OMC evaluation model (Eichas, 2010), and the findings are consistent with the hypothesis that in addition to having effects on targeted positive outcomes, PYD interventions are likely to have progressive cascading effects on untargeted problem outcomes that operate through effects on positive outcomes.
Resumo:
The purpose of this study was to evaluate the impact of the ropes course on the self-esteem of undergraduate and graduate students. The ropes course provides challenging experiential activities that facilitate personal confidence and group teamwork. The study relates to adult education, experiential education, and program evaluation within the context of hospitality and tourism management education. Quantitative data were based on the assessment of self-esteem through the completion of the Coopersmith Self-Esteem Inventory (SEI-C) modified for this study. Qualitative data were based on assessment of participants' reflective papers stating their perceptions of the ropes course. ^ The study compared a treatment group (31 undergraduate and 25 graduate students) which participated in the ropes course, and a control group (31 undergraduate and 25 graduate students) which did not participate. Both groups completed the pre- and post-treatment SEI-C at the same time intervals. The quantitative data were analyzed using a two-way repeated-measures analysis of variance (ANOVA). The qualitative data, comprised of reflective papers voluntarily written by 44 (79%) of the treatment group, were coded using four major themes reflecting the students' perceptions about the ropes course. ^ Scores on the pretest and posttest of the SEI-C were not significantly different for the two groups. The qualitative data showed a favorable impact of the ropes course. The discrepancy in the outcomes based on these two measures suggests that the SEI-C self-report paper-and-pencil instrument may not be sufficiently refined to evaluate the complex issue of self-esteem. The SEI-C, if used, should be supplemented by other evaluation measures, since the two measures may be evaluating different components of self-esteem. They may be also differentially affected by bias in scoring, or by statistical characteristics of reliability and validity. ^
Resumo:
The purpose of this study was to create a scale that could measure compartmentalization. In the first of two studies 311 working undergraduates were asked to indicate agreement with 119 items that measured compartmentalization. The resulting scale's reliability and validity were evaluated by having a second sample of 312 working students complete the items that comprise a sphere overlap scale, two measures of spillover, and a measure of personality, coping, and demoralization. Although the study's original goal was not realized, its procedures were successful in developing a short (10-item) measure of work-to-home spillover whose items loaded on a single factor. Structural equation modeling indicated that SOS items were correlated with existing measures of spillover and could be discriminated from related concepts of personality and coping. The SOS was also more highly correlated with demoralization than existing measures of spillover in hierarchical analyses that controlled for demographic factors, personality characteristics, and coping style. It is concluded that the SOS shows enough promise to warrant the cost of its appraisal as an alternative measure of spillover in a longitudinal study.
Resumo:
The dissertation reports on two studies. The purpose of Study I was to develop and evaluate a measure of cognitive competence (the Critical Problem Solving Skills Scale – Qualitative Extension) using Relational Data Analysis (RDA) with a multi-ethnic, adolescent sample. My study builds on previous work that has been conducted to provide evidence for the reliability and validity of the RDA framework in evaluating youth development programs (Kurtines et al., 2008). Inter-coder percent agreement among the TOC and TCC coders for each of the category levels was moderate to high, with a range of .76 to .94. The Fleiss’ kappa across all category levels was from substantial agreement to almost perfect agreement, with a range of .72 to .91. The correlation between the TOC and the TCC demonstrated medium to high correlation, with a range of r(40)=.68, p Study II reports an investigation of a positive youth development program using an Outcome Mediation Cascade (OMC) evaluation model, an integrated model for evaluating the empirical intersection between intervention and developmental processes. The Changing Lives Program (CLP) is a community supported positive youth development intervention implemented in a practice setting as a selective/indicated program for multi-ethnic, multi-problem at risk youth in urban alternative high schools in the Miami Dade County Public Schools (M-DCPS). The 259 participants for this study were drawn from the CLP’s archival data file. The study used a structural equation modeling approach to construct and evaluate the hypothesized model. Findings indicated that the hypothesized model fit the data (χ2 (7) = 5.651, p = .83; RMSEA = .00; CFI = 1.00; WRMR = .319). My study built on previous research using the OMC evaluation model (Eichas, 2010), and the findings are consistent with the hypothesis that in addition to having effects on targeted positive outcomes, PYD interventions are likely to have progressive cascading effects on untargeted problem outcomes that operate through effects on positive outcomes.
Resumo:
Little is known about students’ perceptions of online enrollment processes. Student satisfaction is part of the assessment required for accreditation, but evidence suggests that college administrators are oriented to retention and graduation rates rather than to consumer perception. The purpose of this descriptive quantitative study was to develop and validate a model that enables the measurement of online enrollment processes by the analysis of the students’ perceptions. The theoretical framework used to support this study was the process virtualization theory while the conceptual framework was based on Technology Acceptance Model (TAM). TAM is the most valid framework for studying user acceptance of technology and virtual processes. The model was modified, adding a new variable to fit this study. Research questions were used to determine if an institution knows how its students perceive online enrollment processes and how they can become more efficient and effective, improving usage and satisfaction. Descriptive data were collected and analyzed in phases: the pilot study phase, data collection phase, and analysis phases. Inferential statistics were used to draw information from sampled observations of the population; a Cronbach Alpha was conducted to determine the reliability and validity of the model. The study demonstrated that the modified TAM is valid, reliable, and fit to assess the perceptions of the users of online enrollment processes. This study will effect positive social change by providing enrollment managers and administrators information on how to analyze the acceptance their online enrollment processes from the perspective of their students as customers of an institution of higher learning.
Resumo:
The purpose of this study was to examine the phenomenological aspect in the empowerment process of mothers of children with disabilities, and to determine if the coding categories used by Dunst & Trivette (1996) could be replicated. Three mothers of children with disabilities agreed to participate in the study. A semistructured interview was used to determine the specific events that lead to empowerment. Interviews were audio-taped and transcribed by the researcher. Fifteen coding categories and four majors themes of empowerment were identified. Triangulation was used to assure reliability and validity. The findings demonstrated that the coding stages of empowerment as outlined by Dunst & Trivette (1996) are reproducible, as well as the envisionment of the future for their children is the essence of empowerment for these mothers. Specific suggestions are made by which occupational therapists can facilitate the empowerment process of mothers who have children with disabilities.
Resumo:
BACKGROUND: The Pro Children Eating Habits Questionnaire has been evaluated as a valid and reliable tool in Europe to measure determinants of fruit and vegetable intake for children; however, it has not been validation for United States populations. The purpose of this study was to (1) assess the reliability and discrimination validity of fruit and vegetable correlates for the Pro Children Eating Habits Questionnaire; (2) investigate the predictive validity of determinants of fruit and vegetable consumption for multi-ethnic elementary school children; and, (3) to assess the association of social determinants with fruit and vegetable consumption. METHODS: One hundred and thirty elementary school students from the 3rd and 5th grades completed this cross-sectional study. RESULTS: Fruit and vegetable determinants, had satisfactory internal consistencies. No differences were found between the test and the retest for the individual questions with the exception of the question for mean perceived vegetable intake. The discriminatory validity indicated the questionnaire could show differences across grade and gender levels for barriers of fruit and vegetables but not for other factors. Grade together with gender explained barriers to eating fruit and vegetables. Greater availability of fruit in the home and school was associated with higher frequency of consumption. CONCLUSIONS: The results of this study indicate the Pro-Children Eating Habits Questionnaire may be a reliable and valid tool for assessing fruit and vegetable consumption of children in the United States.
Resumo:
This thesis extends previous research on critical decision making and problem-solving by refining and validating a self-report measure designed to assess the use of critical decision making and problem solving in making life choices. The analysis was conducted by performing two studies, and therefore collecting two sets of data on the psychometric properties of the measure. Psychometric analyses included: item analysis, internal consistency reliability, interrater reliability, and an exploratory factor analysis. This study also included regression analysis with the Wonderlic, an established measure of general intelligence, to provide preliminary evidence for the construct validity of the measure.
Resumo:
Success in mathematics has been identified as a predictor of baccalaureate degree completion. Within the coursework of college mathematics, College Algebra has been identified as a high-risk course due to its low success rates. ^ Research in the field of attribution theory and academic achievement suggests a relationship between a student's attributional style and achievement. Theorists and researchers contend that attributions influence individual reactions to success and failure. They also report that individuals use attributions to explain and justify their performance. Studies in mathematics education identify attribution theory as the theoretical orientation most suited to explain academic performance in mathematics. This study focused on the relationship among a high risk course, low success rates, and attribution by examining the difference in the attributions passing and failing students gave for their performance in College Algebra. ^ The methods for the study included a pilot administration of the Causal Dimension Scale (CDSII) which was used to conduct reliability and principal component analyses. Then, students (n = 410) self-reported their performance on an in-class test and attributed their performance along the dimensions of locus of causality, stability, personal controllability, and external controllability. They also provided open-ended attribution statements to explain the cause of their performance. The quantitative data compared the passing and failing groups and their attributions for performance on a test using One-Way ANOVA and Pearson chi square procedures. The open-ended attribution statements were coded in relation to ability, effort, task difficulty, and luck and compared using a Pearson chi square procedure. ^ The results of the quantitative data comparing passing and failing groups and their attributions along the dimensions measured by the CDSII indicated statistical significance in locus of causality, stability, and personal controllability. The results comparing the open-ended attribution statements indicated statistical significance in the categories of effort and task difficulty. ^
Resumo:
Over the last 10 years, the development and the understanding of the mechanical properties of thin film material have been essential for improving the reliability and lifetime in operation of microelectromechanical systems (MEMS). Although the properties of a bulk material might be well characterized, thin-film properties are considerably different from those of the bulk and it cannot be assumed that mechanical properties measured using bulk specimens will apply to the same materials when used as a thin film in MEMS. For many microelectronic thin films, the material properties depend strongly on the details of the deposition process and the growth conditions on its substrate. ^ The purpose of this dissertation is to determine the temperature dependence of a gold thin film membrane on the pull down voltage of a MEMS switch as the temperature is varied from room temperature (300 K) to cryogenic temperature (10 K). For this purpose, an RF MEMS shunt switch was designed and fabricated. The switch is composed of a gold coplanar waveguide structure with a gold bridge membrane suspended above an area of the center conductor which is covered by a dielectric (BaTiO3). The gold membrane is actuated by an electrostatic force acting between the transmission line and the membrane when voltage is applied. ^ Material characterization of the gold evaporated thin film membrane was obtained via AFM, SEM, TEM and X-ray diffraction analyses. A mathematical relation was used to estimate the pull down voltage of the switch at cryogenic temperature and results showed that the mathematical theory match the experimental values of the tested MEMS switches. ^
Resumo:
The tragic events of September 11th ushered a new era of unprecedented challenges. Our nation has to be protected from the alarming threats of adversaries. These threats exploit the nation's critical infrastructures affecting all sectors of the economy. There is the need for pervasive monitoring and decentralized control of the nation's critical infrastructures. The communications needs of monitoring and control of critical infrastructures was traditionally catered for by wired communication systems. These technologies ensured high reliability and bandwidth but are however very expensive, inflexible and do not support mobility and pervasive monitoring. The communication protocols are Ethernet-based that used contention access protocols which results in high unsuccessful transmission and delay. An emerging class of wireless networks, named embedded wireless sensor and actuator networks has potential benefits for real-time monitoring and control of critical infrastructures. The use of embedded wireless networks for monitoring and control of critical infrastructures requires secure, reliable and timely exchange of information among controllers, distributed sensors and actuators. The exchange of information is over shared wireless media. However, wireless media is highly unpredictable due to path loss, shadow fading and ambient noise. Monitoring and control applications have stringent requirements on reliability, delay and security. The primary issue addressed in this dissertation is the impact of wireless media in harsh industrial environment on the reliable and timely delivery of critical data. In the first part of the dissertation, a combined networking and information theoretic approach was adopted to determine the transmit power required to maintain a minimum wireless channel capacity for reliable data transmission. The second part described a channel-aware scheduling scheme that ensured efficient utilization of the wireless link and guaranteed delay. Various analytical evaluations and simulations are used to evaluate and validate the feasibility of the methodologies and demonstrate that the protocols achieved reliable and real-time data delivery in wireless industrial networks.
Resumo:
The purpose of this investigation was to develop and implement a general purpose VLSI (Very Large Scale Integration) Test Module based on a FPGA (Field Programmable Gate Array) system to verify the mechanical behavior and performance of MEM sensors, with associated corrective capabilities; and to make use of the evolving System-C, a new open-source HDL (Hardware Description Language), for the design of the FPGA functional units. System-C is becoming widely accepted as a platform for modeling, simulating and implementing systems consisting of both hardware and software components. In this investigation, a Dual-Axis Accelerometer (ADXL202E) and a Temperature Sensor (TMP03) were used for the test module verification. Results of the test module measurement were analyzed for repeatability and reliability, and then compared to the sensor datasheet. Further study ideas were identified based on the study and results analysis. ASIC (Application Specific Integrated Circuit) design concepts were also being pursued.
Resumo:
Distance learning is growing and transforming educational institutions. The increasing use of distance learning by higher education institutions and particularly community colleges coupled with the higher level of student attrition in online courses than in traditional classrooms suggests that increased attention should be paid to factors that affect online student course completion. The purpose of the study was to develop and validate an instrument to predict community college online student course completion based on faculty perceptions, yielding a prediction model of online course completion rates. Social Presence and Media Richness theories were used to develop a theoretically-driven measure of online course completion. This research study involved surveying 311 community college faculty who taught at least one online course in the past 2 years. Email addresses of participating faculty were provided by two south Florida community colleges. Each participant was contacted through email, and a link to an Internet survey was given. The survey response rate was 63% (192 out of 303 available questionnaires). Data were analyzed through factor analysis, alpha reliability, and multiple regression. The exploratory factor analysis using principal component analysis with varimax rotation yielded a four-factor solution that accounted for 48.8% of the variance. Consistent with Social Presence theory, the factors with their percent of variance in parentheses were: immediacy (21.2%), technological immediacy (11.0%), online communication and interactivity (10.3%), and intimacy (6.3%). Internal consistency of the four factors was calculated using Cronbach's alpha (1951) with reliability coefficients ranging between .680 and .828. Multiple regression analysis yielded a model that significantly predicted 11% of the variance of the dependent variable, the percentage of student who completed the online course. As indicated in the literature (Johnson & Keil, 2002; Newberry, 2002), Media Richness theory appears to be closely related to Social Presence theory. However, elements from this theory did not emerge in the factor analysis.
Resumo:
High efficiency of power converters placed between renewable energy sources and the utility grid is required to maximize the utilization of these sources. Power quality is another aspect that requires large passive elements (inductors, capacitors) to be placed between these sources and the grid. The main objective is to develop higher-level high frequency-based power converter system (HFPCS) that optimizes the use of hybrid renewable power injected into the power grid. The HFPCS provides high efficiency, reduced size of passive components, higher levels of power density realization, lower harmonic distortion, higher reliability, and lower cost. The dynamic modeling for each part in this system is developed, simulated and tested. The steady-state performance of the grid-connected hybrid power system with battery storage is analyzed. Various types of simulations were performed and a number of algorithms were developed and tested to verify the effectiveness of the power conversion topologies. A modified hysteresis-control strategy for the rectifier and the battery charging/discharging system was developed and implemented. A voltage oriented control (VOC) scheme was developed to control the energy injected into the grid. The developed HFPCS was compared experimentally with other currently available power converters. The developed HFPCS was employed inside a microgrid system infrastructure, connecting it to the power grid to verify its power transfer capabilities and grid connectivity. Grid connectivity tests verified these power transfer capabilities of the developed converter in addition to its ability of serving the load in a shared manner. In order to investigate the performance of the developed system, an experimental setup for the HF-based hybrid generation system was constructed. We designed a board containing a digital signal processor chip on which the developed control system was embedded. The board was fabricated and experimentally tested. The system's high precision requirements were verified. Each component of the system was built and tested separately, and then the whole system was connected and tested. The simulation and experimental results confirm the effectiveness of the developed converter system for grid-connected hybrid renewable energy systems as well as for hybrid electric vehicles and other industrial applications.