1,720,964 research outputs found
Checking simulations of a geolithological model obtained by means of nested truncated bigaussian method
No full textCharacterizing the spatial distribution of major lithotypes and their relationships is a key aspect in the process of hydrogeological modeling of aquifers in that assignment of lithotypes-specific hydraulic and hydrochemical properties requires the knowledge of the layout of the lithotypes themselves. Truncated bigaussian simulation is a procedure derived from the truncated Gaussian model, used to simulate random sets, and, in particular, variable geological characteristics, expressed as categorical variables. Anyway, in cases of many lithotypes having not homogeneous spatial behaviors, this methodology might not explain at best the relations existing among the lithotypes themselves; a more general method is therefore required to represent this variability. In this paper, that concerns a site whose geologic asset has already been reconstructed, in order to better characterize the aquifer geolithological architecture, nested simulation for a macro-unit of the previously realized geolithologic model has been carried out, together with a check phase of the results obtained by the mentioned simulation. The proposed methodology can represent a useful instrument for the modeling of complex geological layouts other than in the detailed characterizations of hydrogeological studies, for a better interpretation of the complex phenomena that take place in groundwater circulation and contaminant propagation
Stochastic geolithological reconstruction coupled with artificial neural networks approach for hydrogeological modeling
No full textWhen simulating fluid flow and solute transport a more accurate modeling of the lithologic, geological and structural characters of an aquifer is of extreme importance in order to improve the reliability of the numerical simulations. On the other hand the information available for the setting up of a hydrogeological model is subjected to ambiguities due to not univocal interpretations or to uncertainties linked to the methodologies of measurement of the variables of interest. Therefore, hydrogeological characterization of heterogeneous aquifers, if carried out up to a high degree of detail, should not identify a univocal model but a set of "equifinal" solutions. In the present paper the application of Artificial Neural Network approach coupled with a Nested Sequential Indicator simulation has allowed to obtain the distribution of hydrogeologic parameters that are not only conditioned by the in situ measured values but also by the soft information coming from geolithology. The results show a fairly good relationship between parameters such as Transmissivity and Storage coefficient and the geolithologic architecture of the examined aquifer
Checking simulations of a geolithological model obtained by means of nested truncated bigaussian method
No full textCharacterizing the spatial distribution of major lithotypes and their relationships is a key aspect in the process of hydrogeological modeling of aquifers in that assignment of lithotypes-specific hydraulic and hydrochemical properties requires the knowledge of the layout of the lithotypes themselves. Truncated bigaussian simulation is a procedure derived from the truncated Gaussian model, used to simulate random sets, and, in particular, variable geological characteristics, expressed as categorical variables. Anyway, in cases of many lithotypes having not homogeneous spatial behaviors, this methodology might not explain at best the relations existing among the lithotypes themselves; a more general method is therefore required to represent this variability. In this paper, that concerns a site whose geologic asset has already been reconstructed, in order to better characterize the aquifer geolithological architecture, nested simulation for a macro-unit of the previously realized geolithologic model has been carried out, together with a check phase of the results obtained by the mentioned simulation. The proposed methodology can represent a useful instrument for the modeling of complex geological layouts other than in the detailed characterizations of hydrogeological studies, for a better interpretation of the complex phenomena that take place in groundwater circulation and contaminant propagation
Stochastic geolithological reconstruction coupled with artificial neural networks approach for hydrogeological modeling
No full textWhen simulating fluid flow and solute transport a more accurate modeling of the lithologic, geological and structural characters of an aquifer is of extreme importance in order to improve the reliability of the numerical simulations. On the other hand the information available for the setting up of a hydrogeological model is subjected to ambiguities due to not univocal interpretations or to uncertainties linked to the methodologies of measurement of the variables of interest. Therefore, hydrogeological characterization of heterogeneous aquifers, if carried out up to a high degree of detail, should not identify a univocal model but a set of "equifinal" solutions. In the present paper the application of Artificial Neural Network approach coupled with a Nested Sequential Indicator simulation has allowed to obtain the distribution of hydrogeologic parameters that are not only conditioned by the in situ measured values but also by the soft information coming from geolithology. The results show a fairly good relationship between parameters such as Transmissivity and Storage coefficient and the geolithologic architecture of the examined aquifer
Multivariate Geostatistical and Natural Attenuation Model Approach for remediation of chlorinated compounds
No full textModelling spatial variability of environmental parameters through the application of modern techniques of geostatistics has permitted to acquire elements apt to evaluate the possibility of using Natural Attenuation as a remediation technique for groundwater contaminated by chlorinated compounds.
Moreover, a precise delineation of hazardous areas in a polluted site is strongly based on accurate predictions of contaminant concentrations, a task that is complicated by the presence of censored data and highly positively skewed distributions.
The present paper proposes a geostatistical approach that includes different methods for the study and the control of the ongoing activity of Natural Attenuation in an abandoned industrial area. The considered variables in this application are the values of concentration in groundwater of some aliphatic chlorinated carcinogenic compounds (PCE and TCE), measured in numerous piezometers, which show highly skewed distributions, characterized by a considerable number of values below the detection limit of the instrument.
Indicator Kriging has been applied and the areas with 90% probability of exceeding the detection limit have been considered, inside which the variables were transformed through Gaussian Anamorphosis. The application of geostatistics has put into evidence the existence of a correlation between them not only from the chemical point of view, but also from the point of view of their spatial distribution: the shared presence of “hot spot” areas might be imputed to the existence of localized hazard sources. In those areas it is possible to detect coherence between the concentrations of the contaminants in study and the distribution of the parameters that control the phenomenon, which might be considered a clue that the degrading chemical activity is in progress.
Successively, some punctual considerations have been done on the basis of the concentration values of contaminants coming from a following sampling plan on the same area, in order to verify this result. At the same time, an analytical model has been implemented to quantify the Natural Attenuation
The application of multivariate geostatistical techniques for the study of natural attenuation processes of chlorinated compounds
No full textThe application of multivariate geostatistical techniques for the study of natural attenuation processes of chlorinated compounds
No full textModeling spatial variability of environmental parameters through the application of modem techniques of geostatistics has permitted to acquire elements apt to evaluate the possibility of using natural attenuation as a remediation technique for groundwater contaminated by chlorinated compounds. Moreover, a precise delineation of hazardous areas in a polluted site is strongly based on accurate predictions of contaminant concentrations, a task that is complicated by the presence of censored data and highly positively skewed distributions.
The present work proposes a geostatistical approach that includes different methods for the study and the control of the ongoing activity of natural attenuation in an abandoned industrial area. The considered variables in this application are the values of concentration in groundwater of some aliphatic chlorinated carcinogenic compounds (PCE and TCE), measured in numerous piezometers, which show highly skewed distributions, characterized by a considerable number of values below the detection limit of the instrument.
Indicator Kriging has been applied and the areas with 90% probability of exceeding the detection limit have been considered, inside which the variables were transformed through gaussian anamorphosis. The application of geostatistics has put into evidence the existence of a correlation between them not only from the chemical point of view, but also from the point of view of their spatial distribution: the shared presence of "hot spot" areas might be imputed to the existence of localized hazard sources. In those areas it is possible to detect coherence between the concentrations of the contaminants in study and of the parameters that control the phenomenon, which might be considered a clue that the degrading chemical activity is in progress.
In the areas characterized by higher uncertainty for both variables (PCE and TCE), it is possible to presume that the phenomenon of attenuation is in progress, because it is in those areas that the transformations from PCE to TCE may happen in function of the parameters that control the phenomenon
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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