176 research outputs found

    PATHWAY CONNECTIVITY IN AN EPIGENETIC FLUVIOKARST SYSTEM: INSIGHT FROM A NUMERICAL MODELLING STUDY IN KENTUCKY USA

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    Fluviokarst landscapes are dominated by both fluvial and karst features. Interpreting hydrologic pathways of fluviokarst can be confounded by the unknown connectivity of the various flow regimes. A combined discrete-continuum (CDC) hybrid numeric model for simulating the surface and subsurface hydrology and hydraulics in fluviokarst basins was formulated to investigate fluviokarst pathways. This model was applied to the Cane Run Royal Springs basin in Kentucky USA. A priori constraints on parameterization were avoided via multi-stage optimization utilizing Sobol sequencing and high performance computing. Modelling results provide evidence of hydrologic pathways dominated by fracture flow, epikarst transfer and runoff. Fractures in karst basins with high fracture-matrix permeability ratios may influence both springflow and streamflow. Swallet features can be as important as spring features as they are sink features in streamflow during hydrologic events. Inflections in spring hydrographs represent shifts in the surface-subsurface connectivity via the fractures, as opposed to shifts in dominant storage zones. Existing methods of dual- and triunal hydrograph separation of karst springflow may not be directly transferrable to fluviokarst springs. The numerical model herein has advantages of suggesting dominant pathways in complex terrane and highlighting unforeseen surface-subsurface connectivity. However, disadvantages include computational expense and previous site studies

    Mobilizing Social Capital: A Qualitative and Network Analysis of Human Service Organizations

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    Poverty and homelessness is a social problem that impacts all communities in the U.S. and globally. Social programs that address these issues often focus on mobilizing resources to provide opportunities to increase the social position of their clients and meet their basic needs. Sociological research into this problem, however, has emphasized the influence of social connections in the experiences of individuals in poverty. Social capital is the conceptual representation of actual or potential resources obtained through social network connections. Existing literature regarding social capital has demonstrated that social connections are a critical aspect of human social experience and the ability to overcome obstacles and obtain opportunities for upward social mobility, which may provide an opportunity for individuals to escape poverty. However, much of the literature connecting social capital to homelessness has been directed towards examining the social connections of individuals, and therefore, neglects an analysis of the mobilization of social capital in service organizations. This research addresses this lacuna by examining organizational practices and social network structures in a sample of homeless service providers. The purpose of this study was to analyze the practices of human service organizations that promote the development and utilization of their social network connections. This research thus provides a descriptive review of how organizations mobilize social capital in their community to the benefit of their clients. To frame the analysis, I use sociological theories on social capital, resource mobilization, and social networks to investigate the question of how human service organizations leverage their social connections to the benefit of their clients. To investigate this question, I use a thematic analysis of 10 qualitative interviews, with a sample of organizational leaders from 7 organizations, and a sociometric analysis of the network connections between 83 organizations in the sample’s community. The results demonstrate that the organizations use practices that employ social capital to: a) mobilize collective community resources, b) develop trust and reciprocity between providers and clients, c) produce social solidarity between clients and the community, and d) develop social ties that provide social support and opportunities for upward mobility. The findings provide an outline for identifying social capital in organizations, which can be used in future research to evaluate the effectiveness of mobilizing social capital for individuals experiencing periods of poverty and homelessness. Additionally, the results review the challenges and potential benefits of developing organizational networks. This research contributes to sociological theory and academic literature by offering evidence of social capital in connections between entities other than individuals. In conclusion, this study informs social policy and encourages organizations to act as members of a connected network, as opposed to acting as individual service providers

    Boundary Terms and Junction Conditions for the DGP Pi-Lagrangian and Galileon

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    In the decoupling limit of DGP, Pi describes the brane-bending degree of freedom. It obeys second order equations of motion, yet it is governed by a higher derivative Lagrangian. We show that, analogously to the Einstein-Hilbert action for GR, the Pi-Lagrangian requires Gibbons-Hawking-York type boundary terms to render the variational principle well-posed. These terms are important if there are other boundaries present besides the DGP brane, such as in higher dimensional cascading DGP models. We derive the necessary boundary terms in two ways. First, we derive them directly from the brane-localized Pi-Lagrangian by demanding well-posedness of the action. Second, we calculate them directly from the bulk, taking into account the Gibbons-Hawking-York terms in the bulk Einstein-Hilbert action. As an application, we use the new boundary terms to derive Israel junction conditions for Pi across a sheet-like source. In addition, we calculate boundary terms and junction conditions for the galileons which generalize the DGP Pi-lagrangian, showing that the boundary term for the n-th order galileon is the (n-1)-th order galileon.Comment: 23 pages, 1 figure. Extended the analysis to the general galileon field. Version to appear in JHE

    Single-Snapshot File System Analysis

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    Abstract—Metadata snapshots are a common method for gaining insight into filesystems due to their small size and relative ease of acquisition. Since they are static, most researchers have used them for relatively simple analyses such as file size distributions and age of files. We hypothesize that it is possible to gain much richer insights into file system and user behavior by clustering features in metadata snapshots and comparing the entropy within clusters to the entropy within natural partitions such as directory hierarchies. We discuss several different methods for gaining deeper insights into metadata snap-shots, and show a small proof of concept using data from Los Alamos National Laboratories. In our initial work, we see evidence that it is possible to identify user locality information, traditionally the purview of dynamic traces, using a single static snapshot. I

    Weakly-Supervised Semantic Segmentation of Ships Using Thermal Imagery

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    The United States coastline spans 95,471 miles; a distance that cannot be effectively patrolled or secured by manual human effort alone. Unmanned Aerial Vehicles (UAVs) equipped with infrared cameras and deep-learning based algorithms represent a more efficient alternative for identifying and segmenting objects of interest - namely, ships. However, standard approaches to training these algorithms require large-scale datasets of densely labeled infrared maritime images. Such datasets are not publicly available and manually annotating every pixel in a large-scale dataset would have an extreme labor cost. In this work we demonstrate that, in the context of segmenting ships in infrared imagery, weakly-supervising an algorithm with sparsely labeled data can drastically reduce data labeling costs with minimal impact on system performance. We apply weakly-supervised learning to an unlabeled dataset of 7055 infrared images sourced from the Naval Air Warfare Center Aircraft Division (NAWCAD). We find that by sparsely labeling only 32 points per image, weakly-supervised segmentation models can still effectively detect and segment ships, with a Jaccard score of up to 0.756

    Examining the Focus of SoTL Literature—Teaching and Learning?

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    Although the Scholarship of Teaching and Learning (SoTL) claims to focus on student learning, some have argued that SoTL studies often adopt a narrow view of learning and focus more on teaching than on learning. In this paper, we explore whether teaching is the primary focus of recent articles published from 2013-2017 in three international, self-identified SoTL journals: Teaching and Learning Inquiry: The ISSOTL Journal (TLI), The International Journal for the Scholarship of Teaching and Learning (ijSOTL), and The Journal of the Scholarship of Teaching and Learning (JoSoTL). Based on our analysis of the 299 empirical articles, we argue that they portray SoTL as a field focused primarily on teacher activity rather than student learning, despite efforts to broaden its scope

    DataMoves:Entangling data and movement to support computer science education

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    In the domain of computing education for children, much work has been done to devise creative and engaging methods of teaching about programming. However, there are many other fundamental aspects of computing that have so far received relatively less attention. This work explores how the topics of number systems and data representation can be taught in a way that piques curiosity and captures learners’ imaginations. Specifically, we present the design of two interactive physical computing artefacts, which we collectively call DataMoves, that enable students, 12-14 years old, to explore number systems and data through embodied movement and dance. Our evaluation of DataMoves, used in tandem with other pedagogical methods, demonstrates that the form of embodied, exploration-based learning adopted has much potential for deepening students’ understandings of computing topics, as well as for shaping positive perceptions of topics that are traditionally considered boring and dull
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