9,681 research outputs found
User data dissemination concepts for earth resources
Domestic data dissemination networks for earth-resources data in the 1985-1995 time frame were evaluated. The following topics were addressed: (1) earth-resources data sources and expected data volumes, (2) future user demand in terms of data volume and timeliness, (3) space-to-space and earth point-to-point transmission link requirements and implementation, (4) preprocessing requirements and implementation, (5) network costs, and (6) technological development to support this implementation. This study was parametric in that the data input (supply) was varied by a factor of about fifteen while the user request (demand) was varied by a factor of about nineteen. Correspondingly, the time from observation to delivery to the user was varied. This parametric evaluation was performed by a computer simulation that was based on network alternatives and resulted in preliminary transmission and preprocessing requirements. The earth-resource data sources considered were: shuttle sorties, synchronous satellites (e.g., SEOS), aircraft, and satellites in polar orbits
User data dissemination concepts for earth resources: Executive summary
The impact of the future capabilities of earth-resources data sensors (both satellite and airborne) and their requirements on the data dissemination network were investigated and optimum ways of configuring this network were determined. The scope of this study was limited to the continental U.S.A. (including Alaska) and to the 1985-1995 time period. Some of the conclusions and recommendations reached were: (1) Data from satellites in sun-synchronous polar orbits (700-920 km) will generate most of the earth-resources data in the specified time period. (2) Data from aircraft and shuttle sorties cannot be readily integrated in a data-dissemination network unless already preprocessed in a digitized form to a standard geometric coordinate system. (3) Data transmission between readout stations and central preprocessing facilities, and between processing facilities and user facilities are most economically performed by domestic communication satellites. (4) The effect of the following factors should be studied: cloud cover, expanded coverage, pricing strategies, multidiscipline missions
A Baseline Assessment of Furbearers on the Upper Coastal Plain of Virginia
We assessed the status of furbearing mammals on Fort A.P. Hill, Caroline County, Virginia during the 1998-1999 trapping season with the cooperation of local licensed trappers. Our analyses were based on 345 captures representing of 10 mammal species, ranging from one bobcat (Lynx rufus) to 157 beavers (Castor canadensis). Mean number of captures per 100 trap nights was 17.0. Captures varied from 11.9 to 17.9 per 100 trap nights for conibear traps and 9.7 to 18.3 per 100 trap nights for leg-hold traps. External measurements of six species were similar to those reported for other populations in the region. We suggest that valuable insights into the ecology and trends of furbearer populations can be obtained from studies conducted on government installations such as Fort A. P. Hill. Management plans that include evaluations of infectious disease reservoirs and transmission and impacts of furbearers on wetlands, other wildlife, and human activities would aid in long-term evaluation of these mammals from ecosystem and health perspectives
Small Mammal Communities in Riparian and Upland Habitats on the Upper Coastal Plain of Virginia
We compared small mammal communities between riparian (stream corridor) and nearby upland habitats in a hardwood forest ecosystem on Fort A.P. Hill, Caroline County, Virginia. We used a combination of small-scale drift fence/pitfall trap arrays and snap traps to capture small mammals during April ā October 1998, with an additional winter sample in January 1999. We captured seven small mammal species at 14 sites (7 pairs). Numbers of species were not significantly different between habitat types. Bray-Curtis polar ordinations showed that plant and small mammal community compositions were similar in upland sites and that these communities were most varied in riparian sites. Riparian sites supported wetland and moist soil obligate plants that made this habitat type distinct from upland sites. Small mammal communities were dominated by Peromyscus leucopus and Blarina brevicauda. Numbers of individual small mammals captured were higher in riparian sites than in upland sites. Mean number of captures per trap night averaged 2.6 in riparian sites and 1.4 in upland sites but the difference was not statistically significant. Numbers of rodent captures were significantly higher in both habitat types than captures for insectivores. Hardwood habitats in riparian and upland systems support diverse small mammal communities in the upper Coastal Plain of Virginia. Because small mammals use both habitat types extensively, composition of contiguous upland habitats should be considered in studies of these animals in riparian ecosystems
k-d Darts: Sampling by k-Dimensional Flat Searches
We formalize the notion of sampling a function using k-d darts. A k-d dart is
a set of independent, mutually orthogonal, k-dimensional subspaces called k-d
flats. Each dart has d choose k flats, aligned with the coordinate axes for
efficiency. We show that k-d darts are useful for exploring a function's
properties, such as estimating its integral, or finding an exemplar above a
threshold. We describe a recipe for converting an algorithm from point sampling
to k-d dart sampling, assuming the function can be evaluated along a k-d flat.
We demonstrate that k-d darts are more efficient than point-wise samples in
high dimensions, depending on the characteristics of the sampling domain: e.g.
the subregion of interest has small volume and evaluating the function along a
flat is not too expensive. We present three concrete applications using line
darts (1-d darts): relaxed maximal Poisson-disk sampling, high-quality
rasterization of depth-of-field blur, and estimation of the probability of
failure from a response surface for uncertainty quantification. In these
applications, line darts achieve the same fidelity output as point darts in
less time. We also demonstrate the accuracy of higher dimensional darts for a
volume estimation problem. For Poisson-disk sampling, we use significantly less
memory, enabling the generation of larger point clouds in higher dimensions.Comment: 19 pages 16 figure
Alternate forms of cytochrome c in the mi-1 (poky) mutant of Neurospora crassa
Alternate forms of cytochrome c in the mi-1 (poky) mutant of Neurospora crass
Habitat Use by Bats on the Upper Coastal Plain of Virginia
We monitored bat activity on the upper Coastal Plain of Virginia using mist nets and acoustic detection (ANABAT) during April-October 2000 and April-August 2001. We classified forty sites into three forest-cover classes (pine forest, mixed pine, and hardwood forest) and three landscape-feature classes (permanent water, riparian corridor, and upland). We captured 406 bats (8 species) in mist nets; red bats (Lasiurus borealis; n = 281), big brown bats (Eptesicus fuscus; n = 47), and eastern pipistrelles (Pipistrellus subflavus; n = 36) were the most commonly captured species. We captured fewer than 30 individuals of five other species. There were no significant differences in captures per 100 net nights for overall captures or for individual species among forest-cover classes. Overall captures per 100 net nights differed significantly among landscape-feature classes; however, post-hoc analyses could not tease out significantly different pairs. Captures of L. borealis were higher over permanent waters than along riparian corridors or in uplands. Bray-Curtis polar ordination suggested that landscape features such as beaver ponds and impoundments influenced habitat use by bats more than forest-cover type. Discriminant function analysis identified 713 bat calls (ā„ 95% confidence) using ANABAT II detectors. Lasiurus borealis and P. subflavus were more frequently recorded by ANABAT II than northern myotis (Myotis septentrionalis) among the three forest-cover classes and among the three landscape-feature classes. Planned, a priori, contrast indicated that for 25 nights when mists nets and acoustic detectors were used simultaneously, mean number of bat species detected for the pooled results of both techniques was higher than the average number of species detected by the mean of each of the two techniques separately. Mean number of bat species detected by the ANABAT II system was higher than mean number detected by mist netting
VoroCrust: Voronoi Meshing Without Clipping
Polyhedral meshes are increasingly becoming an attractive option with
particular advantages over traditional meshes for certain applications. What
has been missing is a robust polyhedral meshing algorithm that can handle broad
classes of domains exhibiting arbitrarily curved boundaries and sharp features.
In addition, the power of primal-dual mesh pairs, exemplified by
Voronoi-Delaunay meshes, has been recognized as an important ingredient in
numerous formulations. The VoroCrust algorithm is the first provably-correct
algorithm for conforming polyhedral Voronoi meshing for non-convex and
non-manifold domains with guarantees on the quality of both surface and volume
elements. A robust refinement process estimates a suitable sizing field that
enables the careful placement of Voronoi seeds across the surface circumventing
the need for clipping and avoiding its many drawbacks. The algorithm has the
flexibility of filling the interior by either structured or random samples,
while preserving all sharp features in the output mesh. We demonstrate the
capabilities of the algorithm on a variety of models and compare against
state-of-the-art polyhedral meshing methods based on clipped Voronoi cells
establishing the clear advantage of VoroCrust output.Comment: 18 pages (including appendix), 18 figures. Version without compressed
images available on https://www.dropbox.com/s/qc6sot1gaujundy/VoroCrust.pdf.
Supplemental materials available on
https://www.dropbox.com/s/6p72h1e2ivw6kj3/VoroCrust_supplemental_materials.pd
Playful Tarot: Adaptations of Tarot In, Through, and Across Games.
The magical practice of divination through tarot emanates from the sacred, ritualistic power of play. Long before tarot accretes esoteric symbolism as a divinatory tool, Italians played it as the parlour game tarrochi. Extending this history, many games implement tarot as a mechanical framework and a source of visual imagery. Yet, not all implementations of tarot are equally successful artistically and spiritually. Ludic tarot is often mechanistic (just another way to think about buffs and stats) or superficially thematic (visual imagery without underlying semiotic content). In this paper, we will unravel the intertwined history of games and tarot, exploring its relationship to other cartomantic practices, including the dark Gnostic āGame of Saturnā decoded by Peter Mark Adams in the Sola-Busca deck, the pragmatically cryptic Lenormand deck, and the divinatory use of standard 52-card playing decks in folk witchcraft. Building upon this historical insight, we will then analyse three related tabletop games as case studies: Chalice (in which tarot generates narratives of a failed Grail quest), Alas Vegas (which resolves conflict and generates narrative through tarot-driven blackjack), and Invisible Sun (which reinvents tarot through the circular Sooth deck driving its magic system). All three of these games weave resonant connections between the imagery and mechanics of cards and fictional gameworlds, thereby investing tarot with an eerie sense of meaningful coincidence or synchronicity. Understanding the techniques that create a more resonant experience of tarot can open the way for a deeper implementation of tarot in game development, as well as enable playful reflection and insight within the magical practice. Specifically, insights into non-digital ludic implementations of tarot can pave the way for richer and more resonant digital tarot applications, building upon and deepening the recent use of tarot in videogames (such as Tanya X. Shortās Cartomancy anthology and Adam Maloneās VR tarot)
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