1,720,953 research outputs found
Effects of digital elevation model data resolution on hydrological modelling using SWAT: a case study of the Swartkops river catchment
Full text linkDigital Elevation Models (DEMs) are widely used as input to model hydrological processes. Using the appropriate resolution of DEMs is critical in producing accurate simulations of hydrological processes using hydrological models such as the Soil and Water Assessment Tool (SWAT) model. As a result of the availability of DEMs in recent decades and land use/cover (LULC) change impacts on hydrological regimes, the aim of this study was to investigate the effect of DEM data resolution on SWAT model performance for analysing the hydrological response to LULC changes in the Swartkops River catchment. This included using the SWAT model to analyse runoff conditions in the catchment. The main objectives of the study were: (1) to generate LULC maps and analyse LULC changes using Multi-Temporal Landsat TM and OLI images from 1990 to 2022 within the Swartkops catchment using IDRISI Terrset and ArcMap 10.7; (2) to assess the influence of different DEM data resolutions on SWAT model performance via the quantification of model results; and (3) to utilise the SWAT model with optimal performance to analyse the impact of LULC change on the hydrological response (i.e., runoff generation) of the Swartkops catchment using ArcSWAT. To do this, 1990 and 2022 Landsat images were acquired, pre-processed, and classified using supervised image classification via the Maximum Likelihood algorithm. Idrisi Terrset software was used process the Landsat images by generating natural colour composite images which were then used to sample training sites. A stratified random sampling approach was employed which produced spectral signature files which were the basis for employing the Maximum Likelihood classifier to classify the images. Classified images were exported to ArcMap 10.7 where they underwent classification accuracy assessments. An error matrix approach was implemented, and the accuracy of the maps was assessed using the producer’s, user’s, overall and Kappa accuracy. Thereafter, LULC changes were quantified using ArcMap 10.7 by determining the area difference of each LULC type between 1990 and 2022. The SWAT models for the different resolution DEMs (i.e., 20m, 30m, and 90m) were set up on ArcSWAT, and the Swartkops catchment was delineated, subdivided into Hydrological Response Units, and run by inserting all the relevant input data such as LULC data (i.e., 1990, and 2022 classified maps), topographic data (i.e., the DEMs), soil data (i.e., FAO map), and weather data. Statistical evaluations for the performance rating of the models were conducted and incorporated the use of statistical parameters such as Nash-Sutcliffe Efficiency (NSE), Percentage of Bias (PBIAS), Coefficient of determination ((R2), and RMSE-Observation standard deviation ratio (RSR) for assessing the performance of each SWAT model. The model producing the most satisfactory performance was used to compute runoff conditions for the Swartkops catchment. Computations were conducted using the Soil Conservation Service (SCS) curve number method. Fieldwork, which incorporated measuring iii runoff for different LULC types using Gerlach troughs at hillslope scale, was conducted to validate the results of the SWAT model. Results indicated that the 1990 and 2022 LULC maps had an overall accuracy of 87.11% and 94.89%, respectively which was highly satisfactory. The Kappa statistics reflected similar results where the 1990 map had a value of 0.84 while the 2022 map had a value of 0.94, indicating high statistical agreement between the classified maps and the reference data. The study also found that bare areas exuberated the greatest area change with a decline of 9.49%, while built-up areas manifested the highest increase of 5.97% from 1990 to 2022. Agricultural land increased by 4.79% in conjunction with a slight increase of 0.44% by green vegetation while water declined by 1.71%. To determine the ideal DEM to analyse hydrological response, the LULC maps in conjunction with other input data were inserted into the SWAT model to assess model performance. It was found that the 30m produced satisfactory model performance (NSE = 0.49 at calibration and 0.67 at validation) and was eligible to assess runoff conditions as a function of LULC change. Other statistics indicated satisfactory model performance at calibration (PBIAS = 48.80, R2 = 0.51, RSR = 1.02) and validation stage (PBIAS = -38.1, R2 = 0.47, RSR = 1.08). The 90m DEM possessed the poorest model performance (NSE = 0.18 at calibration and 0.35 at validation) followed by the 20m DEM (NSE = 0.41 at calibration and 0.32 at validation). Runoff simulations using the 30m SWAT model showed that surface runoff was highest in areas where there were built-up areas. Built-up areas and bare areas yielded 36% of the total surface runoff individually, while vegetation produced only 28% in 1990. Similar readings were obtained for 2022, which included agricultural land that produced 29% of the surface runoff. Runoff volume measured at hillslope scale was highest in bare areas (6.6 L) and built-up areas (9.3 L). Therefore, this study shows that the resolution of DEMs must concur with the relevant scale of the study to produce optimal results. Additionally, this study showed that a change in LULC heavily affects the amount of surface runoff generated, which has several implications in terms of flooding. Therefore, this study is useful as it will inform sustainable catchment management decisions, and water resource management, and enhance our understanding of the relationships between DEM spatial resolution, LULC change, SWAT modelling, and water quantity calculations.Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 202
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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