Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item EXAMINING THE IMPACT OF PEER ASSISTANCE AND REVIEW (PAR) ON TEACHERS' PRACTICE(2018) Curry, David G.; Timmons-Brown, Stephanie; McLaughlin, Margaret J.; Education Policy, and Leadership; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Researchers, practitioners, and policy makers widely recognize teacher quality as the school-related factor that has the largest influence on a child’s academic performance. While research has documented the central role that teacher quality plays in promoting student achievement, studies have not yet yielded a consensus on the factors that enhance teacher quality. Understanding which professional development practices prove most effective in addressing district needs can potentially impact how district leaders look to improve both teacher performance and teacher retention. Districts must assess the degree to which existing teacher development activities are helping teachers attain key skills. The purpose of this descriptive study was to examine the impact of Peer Assistance and Review (PAR) on the teaching practices of non-tenured teachers as assessed by the teacher observation tool, Framework for Teaching (FfT). This study sought to identify whether there was a statistically significant difference in ratings from a teacher’s first to last formal observation after participating in PAR. In this mixed methods study, quantitative methods were used to examine formal observation data in order determine whether participation in PAR impacted the performance ratings of teachers. Furthermore, qualitative methods, in the form of interviews, were used to gain insight on a teacher’s perception about their participation in PAR and how it has impacted their instructional practices. Results from this study confirm that there was a statistically significant difference in first to last formal observation ratings recorded for all of the eight instructional components tested. Furthermore, data showed that participating teachers believe that their participation in PAR positively influenced the improvement of their instructional practices. This study enriches the literature on Peer Assistance and Review and the impact the program can have on teachers.Item mapping photosynthetically active radiation (PAR) using multiple remote sensing data(2007-07-11) zheng, tao; Liang, Shunlin; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Incident Photosynthetically Active Radiation (PAR) is an important parameter for terrestrial ecosystem models. Presently, deriving PAR using remotely sensed data is the only practical approach to meet the needs for large scale ecosystem modeling. The usefulness of the currently available PAR products is constricted by their limited spatial and temporal resolution. In addition, the applicability of the existing algorithms for deriving PAR using remotely sensed data are limited by their requirements for external atmospheric information. This study develops new algorithms to estimate incident PAR using remotely sensed data from MODIS (Moderate Resolution Imaging Spectroradiometer), GOES (Geostationary Operational Environmental Satellite), and AVHRR (Advanced Very High Resolution Radiometer). The new PAR algorithms differ from existing algorithms in that the new algorithms derive surface properties and atmospheric optical properties using time-series of at-sensor radiance without external atmospheric information. First, a new PAR algorithm is developed for MODIS visible band data. The validity of the algorithm's underpinning theoretical basis is examined and associated errors are analyzed in light of their impact on PAR estimation accuracy. Second, the MODIS PAR algorithm is adapted to AVHRR in order to take advantage of the long data acquisition record of AVHRR. In addition, the scaling of remote sensing derived instantaneous PAR to daily PAR is addressed. Last, the new algorithm is extended to GOES visible band data. Two major improvements of GOES PAR algorithm over that of MODIS and AVHRR are the inclusion of the bi-directional reflectance distribution function for deriving surface reflectance, and the procedure for excluding cloud-shadowed pixels in searching for observations made under clear skies. Furthermore, the topographic impact on PAR is accessed and corrected. To assess the effectiveness of the newly developed PAR algorithms, validation efforts have been made using ground measurements made at FLUXNET sites. The validations indicate that the new PAR algorithms for MODIS, GOES, and AVHRR are capable of reaching reasonably high accuracy with no need for external atmospheric information. This work is the first attempt to develop a unified PAR estimation algorithm for both polar-orbiting and geostationary satellite data. The new algorithms developed in this study have been used to produce incident PAR over North America routinely to support the North America Carbon Program.