Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Adaptive strategy to drought conditions: diurnal variation in water use of a Central Asian desert shrub

Wang S-S., Chen X., Zhou K.-F., Wang Q.

Polish Journal of Ecology

2015

Vol. 63, nr 1

63--76

Water availability is one of the most important factors limiting photosynthetic assimilation of carbon dioxide and growth of individual plants in terrestrial ecosystems. It is especially important for desert shrubs because the diurnal water availability is particularly sensitive to climate change in arid ecosystems. Water use efficiency (WUE) is an indicator of water availability and is frequently used to assess plant performance in various ecosystems, particularly in arid ecosystems. The WUE of plants has been widely assessed using ecological methods and field measurements; however, these approaches are impractical to obtain numerous near-simultaneous estimates of plant water status at the landscape-scale. Consequently, landscape-scale assessments of plant water status are practically pursued through modeling. In this study, measurement and modeling of the diurnal variations of WUE were conducted for a native dominant desert shrub, Tamarix ramosissima, in its original habitat on the periphery of the Gurbantunggut Desert, China. The diurnal net photosynthesis (An), stomatal conductance (gs), and transpiration (Tr) were measured for each individual using a portable photosynthesis system. A coupled model of stomatal conductance, photosynthesis, and transpiration was applied to simulate the diurnal dynamics of An, gs, Tr, and WUE. The model explained 83, 47, 83, and 55% of the variance in the measured An, gs, Tr, and WUE values, respectively, for this desert ecosystem in which T. ramosissima is sparsely distributed. The results demonstrated that the coupled photosynthesis-stomatal conductance-transpiration model strategy is a promising approach to estimate water availability in desert ecosystems in Central Asia.

An Edge-based Image Copy Detection Scheme

Lin C-C., Wang S-S.

Fundamenta Informaticae

2008

Vol. 83, nr 3

299-318

This paper presents a novel scheme to detect copied versions of digital images, particularly in an Internet environment based on edge information of images. The edge information is used to generate the signature set for a corresponding image. The edge-based signature sets are then used to compute the distortions between query images and test images, from among which a user wants to find copies. Experimental results confirm that the proposed scheme not only withstands various modifications of an original image but also offers good detection performance in dealing with various rotations, shifting of 17.5% of the width or height of an image, and cutting out up to 45% of the area of an image, which previous research work has found difficult to detect. Therefore, our proposed scheme could be very helpful in detecting copies of digital images transmitted in an Internet environment.