We propose a strategy in designing an optimal set of filter parameters, such as the order of interpolating polynomial and the filter length for a Savitzky–Golay derivative filter. The proposed strategy is based on the ‘principle of parsimony’ while satisfying the optimality conditions. The optimality conditions are based on the Durbin–Watson lag-1 test statistic and the Derringer–Suich desirability function. While the former checks for an appropriate data fitting, the latter, on the other hand, ensures minimal shape distortion of the reconstructed response. The proposed strategy of designing filter parameters is developed and validated through numerical experiments using Gaussian pulse as a test function which is contaminated with additive white Gaussian noise. In the numerical tests, the polynomial orders used were 3, 5 and 7, but the filter length for each polynomial was varying until the optimality conditions were satisfied. The Savitzky–Golay derivative filtering is used in obtaining the robust reconstruction of noisy geophysical anomaly and the robust estimation of its first- and second-order derivatives. We validated the proposed technique on the published self-potential anomaly data using a data-based interpretation technique where the reconstructed anomaly and its first- and second-order derivatives were used in estimating model parameters. The data-based interpretation using the proposed technique of Savitzky–Golay derivative filtering provides a close agreement with the published results. 相似文献
The main objective of the present research was to examine the risk of fluoride-rich groundwater in the Shanmuganadhi River basin, south India on human health. The non-carcinogenic risks were estimated into two classes: (1) risks associated with oral intake of water and (2) risks associated with dermal contact. Hazard Quotient for oral intake and dermal contact was separately calculated for adult men, adult women and children from the geochemical results of 61 representative samples collected from the wells constructed in hard rock aquifers during the post- (January-2018) and pre-monsoon (May-2018) seasons. The collected samples were analyzed immediately after the field work for all the major ions and fluoride. Finally, total hazard index was calculated for adults (men and women) and children to evaluate the risk. It directed that 41%, 49% and 74% of post-monsoon samples and 30%, 43% and 62% of pre-monsoon samples possessed a non-carcinogenic risk for men, women and children, respectively. Because the basin falls in the drought-prone region, the water supply for drinking and cultivation are commonly based on groundwater resources. The study revealed that the minerals such as apatite, fluorite, biotite and pyroxene in the hornblende–biotite gneiss formation contribute fluoride ions to the groundwater system due to water–rock interaction mechanism. The Durov diagram depicted that dissolution of silicate minerals and cation exchange are the foremost hydrogeochemical activities, which decide the overall chemical composition of groundwater in this region. The ionic concentrations including fluoride increased with respect to depth of occurrence of groundwater. Escalation of the water table due to monsoon recharge and artificial recharge through a check dam decreased the total dissolved solids and fluoride ion concentration. The investigation conducted around the existing check dam at Kaldurai village highlighted that the fluoride concentration is below the allowable limit of 1.5 mg/l (WHO in World health statistics 2017: monitoring health for the SDGs, Sustainable Development Goals. World Health Organization, Geneva, 2017) in the wells closer to the check dam toward the downstream side. The concentration increased with distance, which lead the groundwater unsuitable for consumption. Therefore, it is recommended to implement the managed aquifer recharge using check dams in the other parts of the basin to enrich the quantity and applicability of groundwater.
A cosmological model has been constructed in the framework of Brans-Dicke(BD) gravity,based on an inter-conversion between matter and dark energy, for a spatially flat universe in the era of pressureless dust. To account for the non-conservation of the matter content, a function of time f(t) has been arbitrarily put into the expression for the density of matter(ρa^3= f(t)ρ_0 a_0~3). By definition, f(t) is proportional to the matter content of the universe. Using suitable ansatzes for the scale factor and scalar field, the functional form of f(t) has been determined from the BD field equations. The scale factor has been so chosen that it would cause a signature flip in the deceleration parameter with time. The function f(t) decreases monotonically with time, indicating a transformation of matter into dark energy. The time dependence of the proportions of matter and dark energy in the universe has been determined. The effect of non-conservation of the matter content upon various cosmological parameters has been explored in the present study. Two models of matter-energy interaction have been proposed and f(t) has been expressed as a function of their interaction term. The dark energy equation-of-state(EoS) parameter has been expressed and analyzed in terms of f(t). 相似文献
Present study deals with the vegetation type mapping, structure and composition analysis of the tropical forests, spread over
1,294 km2 area in South Andaman Islands. Seventeen vegetation classes spreading over 89.92% forested area of the islands were mapped
with the overall accuracy of 88.89%. Evergreen, semi-evergreen and mangrove forests were reasonably well distributed forests,
while moist deciduous and littoral evergreen were narrowly restricted. The stocking was quite variable across the forest types.
60.04% of forested area was under medium to high canopy density. Secondary and degraded forest types were mapped. Information
on floristic composition, structure and diversity of various forest types were obtained from 84 field sample plots. An inventory
of 423 species of plants from 101 families included 155 trees, 84 shrubs, 150 herbs and 84 climbers. Tree density and mean
basal area ranged from 517 to 900 stems ha−1 and 36.15 to 53.58 m2 ha−1 respectively. Evergreen forests accounted for highest diversity followed almost equally by semi-evergreen and moist deciduous
forests. 相似文献
Landscape ecology, inter alia, addresses the question as to how altered landscape patterns affect the distribution, persistence, and abundance of a species.
Landscape ecology plays an important role in integrating the different scales of biodiversity from habitat patch to biome
level. Satellite remote sensing technology with multi-sensor capabilities offers multi-scale information on landscape composition
and configuration. Advances in geospatial analytical tools and spatial statistics have improved the capability to quantify
spatial heterogeneity. Globally, landscape level characterization of biodiversity has become an important discipline of science.
Considering the vast extent, heterogeneity, and ecological and economic importance of forest landscapes, significant efforts
have been made in India during the past decade to strengthen landscape level biodiversity characterization. The generic frame
work of studies comprises preparation of national databases providing information on composition and configuration of different
landscapes using multi-scale remote sensing techniques, understanding the landscape patterns using geospatial models to elicit
disturbance and diversity patterns and application of this information for bioprospecting and conservation purposes. Studies
on hierarchical linkage of multi-scale information to study the processes of change, landscape function, dynamics of habitat
fragmentation, invasion, development of network of conservation areas based on the understanding of multi-species responses
to landscape mosaics, macro-ecological studies to understand environment and species richness, habitat and species transitions
and losses, landscape level solutions to adaptation and mitigation strategies to climate change are a few of the future challenges.
The paper presents the current experiences and, analyses in conjunction with international scenario and identifies future
challenges of Indian landscape level biodiversity studies. 相似文献
Fisheries are complex human-in-nature systems. The conventional approach to fisheries systems has been to treat them as predictable and controllable. As complex systems they are neither of the two and have to be approached differently. Complex systems often exhibit the capacity to self-organize or adapt, even without outside influence. If this is true of fisheries, it should lead to a radically different approach to management of fisheries systems that places much emphasis on enabling self-organization, learning and adaptation. Conceptual and practical frameworks for enabling activities are needed. 相似文献