2,884 research outputs found

    Using Lidar to geometrically-constrain signature spaces for physics-based target detection

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    A fundamental task when performing target detection on spectral imagery is ensuring that a target signature is in the same metric domain as the measured spectral data set. Remotely sensed data are typically collected in digital counts and calibrated to radiance. That is, calibrated data have units of spectral radiance, while target signatures in the visible regime are commonly characterized in units of re°ectance. A necessary precursor to running a target detection algorithm is converting the measured scene data and target signature to the same domain. Atmospheric inversion or compensation is a well-known method for transforming mea- sured scene radiance values into the re°ectance domain. While this method may be math- ematically trivial, it is computationally attractive and is most e®ective when illumination conditions are constant across a scene. However, when illumination conditions are not con- stant for a given scene, signi¯cant error may be introduced when applying the same linear inversion globally. In contrast to the inversion methodology, physics-based forward modeling approaches aim to predict the possible ways that a target might appear in a scene using atmospheric and radiometric models. To fully encompass possible target variability due to changing illumination levels, a target vector space is created. In addition to accounting for varying illumination, physics-based model approaches have a distinct advantage in that they can also incorporate target variability due to a variety of other sources, to include adjacency target orientation, and mixed pixels. Increasing the variability of the target vector space may be beneficial in a global sense in that it may allow for the detection of difficult targets, such as shadowed or partially concealed targets. However, it should also be noted that expansion of the target space may introduce unnecessary confusion for a given pixel. Furthermore, traditional physics-based approaches make certain assumptions which may be prudent only when passive, spectral data for a scene are available. Common examples include the assumption of a °at ground plane and pure target pixels. Many of these assumptions may be attributed to the lack of three-dimensional (3D) spatial information for the scene. In the event that 3D spatial information were available, certain assumptions could be levied, allowing accurate geometric information to be fed to the physics-based model on a pixel- by-pixel basis. Doing so may e®ectively constrain the physics-based model, resulting in a pixel-specific target space with optimized variability and minimized confusion. This body of work explores using spatial information from a topographic Light Detection and Ranging (Lidar) system as a means to enhance the delity of physics-based models for spectral target detection. The incorporation of subpixel spatial information, relative to a hyperspectral image (HSI) pixel, provides valuable insight about plausible geometric con¯gurations of a target, background, and illumination sources within a scene. Methods for estimating local geometry on a per-pixel basis are introduced; this spatial information is then fed into a physics-based model to the forward prediction of a target in radiance space. The target detection performance based on this spatially-enhanced, spectral target space is assessed relative to current state-of-the-art spectral algorithms

    Project-Based Learning and Perceived Overlap of Self-Regulation and Project-based Learning Techniques for Students with Adverse Childhood Experiences: A Case Study

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    The purpose of this qualitative case study was to explore the perception of educators transitioning from a traditional learning environment to a project-based learning (PBL). Teachers’ perception of student self-regulation in ages from 8 to 17 were captured. Data were collected from 1-1 interviews with five participants with Missouri teacher certification ranging in grade levels from elementary to high school working with a total of 175 students within a mental health residential school throughout Missouri. Additional data were collected from daily logs, participant interviews, behavioral logs, and regulation logs from classrooms of students with the same background as teacher participants over the last four school years, 2018-22, of teachers who have taught project-based learning units. Daily logs, regulation logs, behavioral logs, and participant interview responses were manually coded twice and then coded a third time using electronic coding via NVivo to ensure bias from Dr Foster was not present. This study supports using project-based learning units with students who have a history of  adverse childhood experiences (ACEs). While study findings support the teacher perception that project-based learning activities increase self-regulation from interview responses, regulation logs, and daily logs data could not triangulate this perceived relationship. These findings support the importance of relationships with students with ACEs during PBL to increase self-regulation

    Project-Based Learning and Perceived Effect on Behaviors for Students with Adverse Childhood Experiences: A Case Study

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    The purpose of this qualitative case study was to explore the perception of educators transitioning from a traditional learning environment to a project-based learning activity environment. Teachers’ perceptions of student behaviors ranging in age from 8 to 17 were captured. Data were collected from 1-1 interviews with five participants with Missouri teacher certification ranging in grade levels from elementary to high school working with a total of 175 students within a mental health residential school for children and youth throughout Missouri. Additional data were collected from lesson reflections, lesson plans, behavioral logs, regulation logs, and supplemental data from critical incident reports from classrooms of students with the same background as teacher participants over the last four school years, 2018-22, of teachers who have taught project-based learning units. Study findings support the teacher's perception that project-based learning activities decrease negative behaviors for students with adverse childhood experiences while increasing engagement, academic skills, and self-regulation. Further, implications from these findings support that project-based learning activities increase student choice, allowing students within a residential mental health classroom to have control

    Some Student Perceptions of Grades Received on Speeches

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    Frequent evaluation of student work is standard practice in basic courses. Frequent evaluation assumes a relationship between the evaluation and improved performance. In higher education, evaluations are often expressed as grades. This study examines the relationship between twelve grades students receive on their speeches, and the affective and motivational effects those grades might have. Generally, the study found that students prefer higher grades but are motivated by lower grades. Specifically, the study indicates disparity between instructor intention in using pluses and minuses with grades and student reaction to the pluses and minuses

    The Yuma Territorial Prison Cemetery: Cold Cases of Grave Importance

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    Cemeteries, via grave markers and burial records, usually offer sufficiently scant data to enable a reconstruction of the communities they represent, but cemeteries of total institutions, here, the Yuma Territorial Prison, often yield even less data. With only the variables of ethnicity, sex, prisoner number, date of death, and cause of death, prison conditions were reconstructed for the 111 who died during the prison’s operation (1876-1909), and likely for the other 2,958 who were incarcerated there. First, prisoner number had a high, positive correlation with year of death, indicating that those who died in prison did not live long after incarceration. Further investigation found statistical dependence between the ethnicity of the prisoner and cause (and thus, manner) of death, with tuberculosis disproportionately effecting Hispanics and Native Americans, perhaps suggesting segregation by ethnicity. Hispanics were the only ones shot and killed attempting escape, though numerous escapes were attempted. Also statistically dependent was the decade of death by ethnicity, perhaps reflecting some ethnic sequence of incarceration. Finally, cause and manner of death, over time, were also dependent, likely reflecting deteriorating prison conditions. That so few variables can reveal so much refutes the adage that dead men tell no tales

    Rhodoliths and rhodolith beds

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    Rhodolith (maërl) beds, communities dominated by free living coralline algae, are a common feature of subtidal environments worldwide. Well preserved as fossils, they have long been recognized as important carbonate producers and paleoenvironmental indicators. Coralline algae produce growth bands with a morphology and chemistry that record environmental variation. Rhodoliths are hard but often fragile, and growth rates are only on the order of mm/yr. The hard, complex structure of living beds provides habitats for numerous associated species not found on otherwise entirely sedimentary bottoms. Beds are degraded locally by dredging and other anthropogenic disturbances, and recovery is slow. They will likely suffer severe impacts worldwide from the increasing acidity of the ocean. Investigations of rhodolith beds with scuba have enabled precise stratified sampling that has shown the importance of individual rhodoliths as hot spots of diversity. Observations, collections, and experiments by divers have revolutionized taxonomic studies by allowing comprehensive, detailed collection and by showing the large effects of the environment on rhodolith morphology. Facilitated by in situ collection and calibrations, corallines are now contributing to paleoclimatic reconstructions over a broad range of temporal and spatial scales. Beds are particularly abundant in the mesophotic zone of the Brazilian shelf where technical diving has revealed new associations and species. This paper reviews selected past and present research on rhodoliths and rhodolith beds that has been greatly facilitated by the use of scuba

    Quark mass dependence of hadron masses from lattice QCD

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    We discuss lattice methods to obtain the derivatives of a lattice meson mass with respect to the bare sea and valence quark masses. Applications are made to quenched and dynamical fermion configurations. We find evidence for significant differences between quenched and dynamical fermion configurations. We discuss how to relate dependence on the bare lattice parameters to more phenomenologically useful quantities.Comment: 18 pages, 5 figures, typos fixed and reference adde
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