نتایج جستجو برای: semi cover
تعداد نتایج: 249360 فیلتر نتایج به سال:
Closed-form analytical expressions and normalized charts provide the conditions for the maximum sensitivity of transverse electric (TE) and transverse magnetic (TM) evanescent-wave step-index waveguide sensors. The analysis covers both cases where the measurand is homogeneously distributed in the semi-infinite waveguide cover, and where it is an ultrathin film at the waveguide-cover interface.
in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...
Extensive changes in land cover during the 20th century are known to have had detrimental effects on biodiversity in rural landscapes, but the magnitude of change and their ecological effects are not well known on regional scales. We digitized historical maps from the beginning of the 20th century over a 1652 km(2) study area in southeastern Sweden, comparing it to modern-day land cover with a ...
In this paper, we introduce a package for semi-supervised learning research in the R programming language called RSSL. We cover the purpose of the package, the methods it includes and comment on their use and implementation. We then show, using several code examples, how the package can be used to replicate well-known results from the semi-supervised learning literature.
1. Restoration of semi-arid shrub ecosystems often requires control of invasive grasses but the effects of these grass-control treatments on native and exotic forbs have not been investigated adequately to assess long-term stability. In southern California, coastal sage scrub (CSS) vegetation is one semi-arid shrub community that has been invaded extensively by both exotic grasses and exotic fo...
The present study discusses a method used to produce updated information about vegetation cover in arid and semi-arid zones, using RS data and GIS technique. In this method, Landsat ETM+ data in 2002 was collected in an area of about 60000 ha in Nodoushan basin, Yazd, Iran. To collect the necessary ground data, 50 sites of different vegetation types were selected and the percentage of vegetatio...
Urban ecosystem assessments increasingly rely on widely available map products, such as the U.S. Geological Service (USGS) National Land Cover Database (NLCD), and datasets that use generic classification schemes to detect and model large-scale impacts of land-cover change. However, utilizing existing map products or schemes without identifying relevant urban class types such as semi-natural, y...
Understanding the spatio-temporal dynamics of land surface phenology is important to understanding changes in landscape ecological processes of semi-arid savannas in Southern Africa. The aim of the study was to determine the influence of variation in tree cover percentage on land surface phenological response in the semi-arid savanna of Southern Africa. Various land surface phenological metrics...
Understanding landscape conversion is vital for assessing the impacts of ecological and anthropogenic disturbances at regional and global scales. Since rangelands cover nearly half of the global land surface, and because a large part of rangelands is located in semi-arid ecosystems, they serve as critical land cover types for determining regional biodiversity, global biogeochemical cycles, and ...
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