University of Maryland, Baltimore County
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Predictors of Parent Involvement in Part C Early Intervention Services
No full textA high degree of parental involvement in early intervention (EI) services for children under age three with developmental delays/disabilities is considered desirable, but there is scant research on predictors of parent involvement in EI. This study adapted a theoretical model of parents' involvement in their children's education and measured three hypothesized predictors of parent involvement in EI: parent role beliefs, parental self-efficacy beliefs, and parental knowledge of child development. Participants were recruited from four county-based EI programs in central and southeastern Ohio (N = 98) to complete questionnaires measuring the three predictors. The EI professionals assigned to each participant reported the participant's attendance and commitment to intervention over the prior six months of enrollment. Hierarchical multiple regression analysis provided partial support for the hypotheses in that parent role beliefs predicted commitment to intervention ratings. No hypothesized predictors were related to attendance. Post-hoc analyses found that specific self-efficacy beliefs and general self-efficacy beliefs each moderated the relation between parent role beliefs and commitment to intervention ratings. Those with high specific parental self-efficacy beliefs/low parent role beliefs had lower commitment to intervention ratings than those with high specific self-efficacy beliefs/high parent role beliefs. Similarly, those with high general self-efficacy beliefs/low parent role beliefs had lower commitment to intervention ratings than those with high general self-efficacy beliefs/high parent role beliefs. Two programs used a written caregiver/provider agreement at enrollment to explain the expectations for involvement in the program. Participants from programs which used written agreements had significantly higher attendance than participants from programs which did not use agreements. Methodological limitations included sampling bias due to recruitment being dependent upon EI providers and volunteer participants, instrumentation issues with the role beliefs measure and the knowledge of child development measure, as well as nesting of participants within professionals and professionals within programs. One implication from the research was that programs should use written agreements at enrollment to clarify expectations for parent involvement. Additional research on parent role beliefs and parental self-efficacy beliefs as well as other predictors of parent involvement in EI is warranted
MODELING AND CONTROL OF AN INFINITELY VARIABLE SPEED CONVERTER WITH APPLICATION TO WIND TURBINES
No full textDifferent types of continuously variable transmission (CVT) have been developed for vehicle and wind turbine applications, which can generate constant-frequency current without using power converters. An infinitely variable speed converter (IVSC) is a type of CVT that can achieve a zero speed ratio and transmit a large torque at low speed ratios. An IVSC with drivers that convert an eccentric motion of cams to a concentric motion of the output shaft through one-way bearings is introduced, and an active control system with a combined feedback and feed forward control that can automatically control the speed ratio of the transmission is developed. The kinematic model of the IVSC is derived and fitted by a polynomial function to serve as the nonlinear feed forward function in the control law. The benefit of the nonlinear feed forward function is exhibited by using it in the control of the Variable Electromotive-Force Generator (VEG). A dynamic model of the IVSC is derived to investigate the effect of the dynamic load on the input and output speeds. Static and dynamic tests were conducted to validate the kinematic model of the IVSC. The variation of the average output speed per revolution of the output shaft is 0.56% with respect to the desired output speed in the simulation and 0.91% in the experiments
EXPLORING METHODS OF ESTIMATING HETEROGENEITY PARAMETERS IN STATISTICAL META-ANALYSIS
No full textIt has been widely recognized that statistical meta-analysis is not only important for estimating average effect size from several studies; but also equally important for investigating and estimating potential sources of heterogeneity of those studies. While the former is known as analytic meta-analysis, we focus more on the latter, which is called exploratory meta-analysis. In meta-analyses, combining results from different studies is likely to imply the existence of heterogeneity due to systematic sources of variation and, possibly, random components which should be considered in a model for exploratory meta-analysis. We refer to the parameter (a scalar or a matrix) describing the variation of the random components as the heterogeneity parameter. When a meta-analysis is done, investigators should consider models which provide for heterogeneity regardless of the size of the heterogeneity parameter as measured by either a scalar quantifying variation (i.e., a variance) or the determinant of a positive definite matrix. This research develops an alternative estimation method, a Hybrid method for estimating heterogeneity parameters in random-effects meta-analysis. It is a Hybrid method because it combines the methods of both moments and iterations in the estimation procedures. Unlike the Sidik and Jonkman method the Hybrid method does not depend on the initial or crude value of the heterogeneity parameter, and it can also be extended to meta-regression and multivariate models. It is a method that provides a positive heterogeneity parameter estimate no matter how homogenous the studies are. In this dissertation, real and simulated data were used to compute the heterogeneity parameters and to compare the performances of the Hybrid method with other estimation methods including the DerSimonian and Laird (DL) method(1986), the maximum likelihood (ML) method (Sidik and Jonkman, 2007), and the restricted maximum likelihood (REML) method (Sidik and Jonkman, 2007). Coverage probabilities of the overall population effect size and bias of the heterogeneity parameter were the basis for comparison in the simulation for one-way and meta-regression models. This research extends to multivariate meta-analysis in random-effects models to compare the Hybrid method with other methods of multivariate meta-analysis. In addition to the Hybrid method, the extended version of Sidik and Jonkman method(2005) is also applied in estimating a matrix of heterogeneity parameters and evaluated against other methods, namely, the extended DerSimonian and Laird methods of Jackson, et al. (2009) and Chen, et al. (2012). In multivariate setup, the extended DL, the restricted maximum likelihood and the maximum likelihood methods are extensively discussed and compared with the underlying Hybrid and the Sidik and Jonkman methods in estimated heterogeneity matrices in terms of distance from the true matrix. Although there are several approaches and methods used in estimating the heterogeneity parameters in random-effects meta-analyses, the proposed Hybrid method is an attractive alternative due to several reasons: it always yields a unique positive value in the univariate case, and a positive definite matrixestimate in multivariate case with better performance in terms of bias from the true parameter and coverage rates closer to the nominal value
Detecting Frequency Dependence in the D14 Coefficient of Dehydrated Cow Bone
No full textControversy exists over the source of strain induced polarization in bone. The debate has spanned five decades and in recent years most authors have focused their attention on the promise of streaming potentials. However, there is strong evidence that traditional piezoelectricity contributes to polarization in bone. But there is also evidence in the literature that piezoelectricity does not act alone. At low frequencies the piezoelectric response was found to be on the order of 100 times greater than at high frequencies in the d31 axial coefficient. When the literature is considered as a whole this disparity is apparent. There is convincing evidence that piezoelectricity acts in conjunction with Maxwell-Wagner effects. Presented here is an examination of the prospect that classic piezoelectricity and Maxwell-Wagner effects are responsible for the disparity observed. Considerable effort is dedicated to detecting the small deformations in bone and distinguishing usable data from electromagnetic and mechanical noise. Because of the sensitivity limitations of the equipment used in the present experiment, only the d14 coefficient was measured. Strong frequency dependence was observed in both the real and imaginary coefficient values. However, the experimental results show no evidence of Maxwell Wagner like dispersion. This is possibly due to the elimination of the microcapillary regions of water. While dry bone is still a composite material composed of mineral and collagen, it is most likely that the Maxwell-Wagner effects, if present, happen at the interface between the pockets of water in bone and the organic regions of hydrated bone
Fast Modular Exponentiation Using Residue Domain Representation: A Hardware Implementation and Analysis
No full textUsing modular exponentiation as an application, we engineered on FPGA fabric and analyzed the first implementation of two arithmetic algorithms in Reduced-Precision Residue Number Systems (RP-RNS): the partial-reconstruction algorithm and quotient-first scaling algorithm. Residue number systems (RNS) provide an alternative representation to the binary system for computation. They offer full parallel computation for addition, subtraction, and multiplication. However, base extension, division, and sign detection become harder operations. Phatak's RP-RNS uses a time-memory trade-off to achieve O(lg N) running time for base extension and scaling, where N is the bit-length of the operands, compared with Kawamura's Cox-Rower architecture and its derivatives, which appear to take O(N) steps and therefore O(N) delay to the best of our knowledge. We implemented the fully parallel RP-RNS architecture based on Phatak's description and architecture diagrams. Our design decisions included distributing the lookup tables among each channel, removing the adder trees, and removing the parallel table access thus trading size for speed. In retrospect, we should have hosted the tables in memory off the FPGA. We measured the FPGA utilization, storage size, and cycle counts. The data we present, though less than optimal, confirms the theoretical trends calculated by Phatak. FPGA utilization grows proportional K log(K) where K is the number of hardware channels. Storage grows proportional to O(N^3 lg lg N). When using Phatak's recommendations, cycle count grows proportional to O(lg N). Our contributions include documentation of our design, architecture, and implementation; a detailed testing methodology; and performance data based on our implementation to enable others to replicate our implementation and findings
The Physiological, Ecological, and Evolutionary Basis of Polychromatic Ultraviolet Sensitivity In Stomatopod Crustaceans
No full textThe eyes of stomatopods are the most functionally diverse photoreceptor array found in nature. These marine crustaceans possess at least sixteen spectral types of photoreceptors, as well as sensitivity to various forms of polarized light. These visual aptitudes are the product of a variety of unique anatomical, neurological, molecular, and optical modifications to the retina and optical components of the eye. The sixteen peak sensitivities of their photoreceptors are spread evenly from 310 nm in the deep ultraviolet to 700 nm in the far-red. While the optics, visual pigments, and behavioral sensitivity of these photoreceptors have been examined in great detail at human-visible wavelengths, little is known about the UV receptors beyond their electrophysiological spectral sensitivities. Here, I present a physiological explanation for the five narrowly tuned ultraviolet receptor types in the retina of the stomatopod, Neogonodactylus oerstedii, including opsin transcript expression, visual pigment absorption, and the discovery of a unique ultraviolet-specific optical filter pigment set found in the crystalline cones of the midband. Additionally, I present a survey of these filters in twenty-one additional species of stomatopods, including data on their diverse absorbance spectra, a reconstruction of their evolution in the order, and the factors influencing their spectral tuning. Furthermore, this broad survey identifies additional ultraviolet filters in the peripheral ommatidia, suggesting an even greater level of photoreceptor spectral specialization than was previously estimated in these animals. Finally, I present behavioral evidence for ultraviolet sensitivity in stomatopods, as well as ultraviolet reflectance patterns associated with their threat displays, that may represent a covert deep-ultraviolet communication system
Stateless Detection of Malicious Traffic: Emphasis on User Privacy
No full textIn order to allow flexibility in deployment location and to preserve user privacy we have performed research into stateless classification of network traffic. Stateless detection allows for feasibility in deployment location because traffic on a network does not necessarily follow the same path to and from the end points. By only requiring a single direction of traffic, we have the ability to deploy this classifier anywhere on a network. We also do not require the data from a packet which preserves user privacy and allows for the classification of encrypted traffic. Our research shows that it is possible to determine if traffic is malicious by using packets traveling in a single direction and without the data contained in the packet. Our research shows that with the use of the timing of the packets, time to live value, and source and destination IP addresses and ports, it is possible to determine if the traffic is malicious. In this way we are able to deploy the classifier anywhere on a network, preserve user privacy, and classify encrypted traffic
Chronic Illness Narratives: Conceptualizations of a Cancer Diagnosis Among Chronically Ill Older Adults
No full textChronically-ill older adults (age 65+) who receive a new cancer diagnosis face many unique challenges (e.g., medication management, fractioning of care, etc.), yet very little had been known about how this group of individuals understood and attached meaning to their experiences. This qualitative study therefore sought to describe, in part, how chronically ill, older individuals experienced a new cancer diagnosis and the effects this had on their overall healthcare trajectories and notions of personal health, well-being, and life satisfaction. Thus, a series of three, semi-structured interviews was conducted with each of fifteen informants over the course of approximately three weeks. The interviews asked questions that explored each person's life history (Interview One), individual experiences of co-morbid, chronic disease (Interview Two), and direct experiences with cancer and their cancer diagnosis, in particular (Interview Three). The audio-recorded interviews were transcribed for subsequent large-level coding and analyses. Interviews were analyzed thematically to describe how the sample of individuals presented and described the personal meaning of the cancer experience through descriptions of their diagnosis and the events preceding it: the stories of illness, its meaning, and its consequences. In this way, three overarching themes arose from the data: (1) Time in Illness, (2) Meaning of Illness, and (3) Identity as Affected by Illness. There were a variety of subthemes and these are all discussed at length throughout the dissertation. Understanding how each of these areas connects to the illness experience enhances the quality of illness management by eliciting common areas of stress throughout the diagnosis and illness experience for older individuals, particularly in light of multi-morbidity
Oppositional Narratives: Embedded Tales, Social Justice, and the Reader
No full textOppositional narratives are texts that work to disrupt dominant ideology and interrogate social injustices through tactical and thematic interactions with readers. Tactically, oppositional narratives activate embedded tales, small stories inserted in the frame narratives, to question dominant conceptions about marginalized people. Embedding operates through gathering, retasking, and projecting, which I substantiate with coalitional and rhetorical narrative theories. Oppositional narratives give voice to the silenced and sketch an inclusive humanity that offers hope for social justice by gathering multiple embedded tales that connect heterogeneous individualities across shared experiences, enabling revisions of dominant culture through retasking, and projecting imagined possibilities for change. Through readers' ethical experiences with multiple tales and tellers, oppositional narratives create possibilities for empathy and understanding across differences. I consider how embedded tales work oppositionally in Sanora Babb's Whose Names are Unknown, Marita Bonner's Frye Street and Environs, Jack Conroy's The Disinherited, Jessie Redmon Fauset's Comedy: American Style, Langston Hughes' Not Without Laughter, Josephine W. Johnson's Now in November, Meridel Le Sueur's The Girl, and Tillie Olsen's Yonnondio. Embedded tales empower these narratives thematically to validate social justice for the marginalized through models of oppositional consciousness; disrupt ideological constrictions of those othered by class, race, and gender ideologies; and expose objectifying physical exploitations
Noninvasive Transdermal Glucose Monitoring using a Fluorescent Glucose Binding Protein
No full textThe current technology for determining infant glucose levels uses either a bedside glucose analyzer or a laboratory enzymatic method, which subjects the infant to pain from multiple invasive blood draws. A non-invasive method for neonatal glucose monitoring would be desirable. We exploit transepidermal water loss (TEWL) to detect skin glucose using modified glucose binding protein (GBP) and correlate with blood glucose. This GBP-based assay is four orders of magnitude more sensitive than prior methods. We use a membrane covered glucose-solution filled chamber as a human blood-skin model. Cellulose acetate and porcine ear skin are used as in vitro models for human skin. We successfully demonstrate that surface glucose concentration is proportional to internal concentration for both models. An optimum noninvasive protocol is created using adult volunteers. The GBP detects skin glucose at low concentrations, which correlates well to blood glucose. The GBP assay shows comparable results to the standard analytical method using high-performance anion-exchange chromatography (HPAEC)