2,048 research outputs found

    Holographic interconnections in photorefractive waveguides

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    An architecture for implementing large scale holographic interconnections in photorefractive waveguides is described. Methods for controlling the hologram using unguided light are considered and experimentally demonstrated

    An Explanation of the Supervisory Model used by Elementary Principal Supervisors in the State of Missouri

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    The goal for this paper was to discuss the efforts a school district has taken to utilize elementary principal supervisors to build and develop principals’ leadership capacities. The question considered was: (1) How are principals supervised and evaluated in one district? Attempting to answer this question is an important step in operationalizing guiding principles that can be shared with principal supervisors. The discussion included the importance of standards, the modeling of instructional supervision by principal supervisors, the reliance of guiding questions and potential data sources. Additional critical factors included coaching with two-way communication based on a trusting, reflective relationship. As the role of principals’ leadership is elevated to increase the performance of teachers and thus the academic performance of students, principal supervisors should be able to provide principals ownership in their supervision and evaluation, evaluate performance based on standards and indicators, deliver feedback, develop trusting relationships, all by making frequent visits to principals’ schools to further the application of principals’ instructional leadership

    Survival of the selfish: contrasting self-referential and survival-based encoding

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    Processing information in the context of personal survival scenarios elicits a memory advantage, relative to other rich encoding conditions such as self-referencing. However, previous research is unable to distinguish between the influence of survival and self-reference because personal survival is a self-referent encoding context. To resolve this issue, participants in the current study processed items in the context of their own survival and a familiar other person’s survival, as well as in a semantic context. Recognition memory for the items revealed that personal survival elicited a memory advantage relative to semantic encoding, whereas other-survival did not. These findings reinforce suggestions that the survival effect is closely tied with self-referential encoding, ensuring that fitness information of potential importance to self is successfully retained in memory

    From Caution to College: The Effects on Veterans with Self- Reported Trauma Symptoms Sharing their Experiences with the Campus Community

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    Over 900,000 veterans are using benefits for higher education today; the vast majority of them served in the Global War on Terrorism (GWOT). Over 25% of GWOT service members that have been treated by the Veterans Affairs (VA) are reported to have symptoms of posttraumatic stress or posttraumatic stress disorder (PTS/PTSD). PTS/PTSD negatively impacts student veterans’ abilities to navigate stressful environments such as college and university settings. The Veterans Embracing Transition (VET) Connect Program at San José State University (SJSU) is designed to connect veterans with non-veterans as peer educators. Five of the 13 VET Connect peer educators (38.5%) who were interviewed reported having symptoms of PTSD. Through their service as peer educators on and off campus, these participants demonstrated signs of healthy coping effects through sharing experiences and educating non-veterans of the struggles related to military culture, service, combat, and loss. This study was conducted in collaboration with Sophia Alcala. We worked on independent research questions and observations using data derived from the same larger study simultaneously under the supervision of Dr. Klaw

    Visual sensitivity, blur and the sources of variability in the amplitude spectra of natural scenes

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    AbstractA number of researchers have suggested that in order to understand the response properties of cells in the visual pathway, we must consider the statistical structure of the natural environment. In this paper, we focus on one aspect of that structure, namely, the correlational structure which is described by the amplitude or power spectra of natural scenes. We propose that the principle insight one gains from considering the image spectra is in understanding the relative sensitivity of cells tuned to different spatial frequencies. This study employs a model in which the peak sensitivity is constant as a function of frequency with linear bandwith increasing (i.e., approximately constant in octaves). In such a model, the “response magnitude” (i.e., vector length) of cells increases as a function of their optimal (or central) spatial frequency out to about 20 cyc/deg. The result is a code in which the response to natural scenes, whose amplitude spectra typically fall as 1/f, is roughly constant out to 20 cyc/deg. An important consideration in evaluating this model of sensitivity is the fact that natural scenes show considerable variability in their amplitude spectra, with individual scenes showing falloffs which are often steeper or shallower than 1/f. Using a new measure of image structure (the “rectified contrast spectrum” or “RCS”) on a set of calibrated natural images, it is shown that a large part of the variability in the spectra is due to differences in the sparseness of local structure at different scales. That is, an image which is “in focus” will have structure (e.g., edges) which has roughly the same magnitude across scale. That is, the loss of high frequency energy in some images is due to the reduction of the number of regions that contain structure rather than the amplitude of that structure. An “in focus” image will have structure (e.g., edges) across scale that have roughly equal magnitude but may vary in the area covered by structure. The slope of the RCS was found to provide a reasonable prediction of physical blur across a variety of scenes in spite of the variability in their amplitude spectra. It was also found to produce a good prediction of perceived blur as judged by human subjects

    Space-Time Projection Optical Tomography: Search Space and Orbit Determination

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    In a companion article, we discussed the radiometric sensitivity and resolution of a new passive optical sensing technique, Space-Time Projection Optical Tomography (SPOT), to detect and track sub-cm and larger space debris for Space Situational Awareness. SPOT is based on the principle that long synthetic exposure can be achieved if the phase-space trajectory of a hypothetical point-source is precisely predictable within a very wide telescope field-of-view, which is the case for orbiting debris. This article discusses the computational search space for debris mining as well as a recursive measure-and-fit algorithm based on a generalized Hough transform for orbit determination.Comment: Space Situational Awarenes
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