1,720,961 research outputs found
Effects of Channel Characteristics on Time Parameters for Small Watershed Runoff Hydrographs
No full textWater Resources Research CenterGolany, Larson, Curtis L. Pinhas. (1971). Effects of Channel Characteristics on Time Parameters for Small Watershed Runoff Hydrographs. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/91747
Predicting Infiltration and Micro-Relief Surface Storage for Cultivated Soils
No full textWater Resources Research CenterMoore, Ian D.; Larson, Curtis L.; Slack, Donald C.. (1980). Predicting Infiltration and Micro-Relief Surface Storage for Cultivated Soils. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/91374
Modeling Direct Recharge of Surficial Aquifers
No full textA one-dimensional, physically-based computer model was developed for predicting direct groundwater recharge. The model was verified using three years of data from an instrumented site in east central Minnesota. Although the processes of infiltration and redistribution during frozen soil periods were not modeled, the model is capable of operating during both frozen and non-frozen soil periods. The model includes submodels for evapotranspiration, soil water extraction, snowmelt, surface depressional storage, infiltration and redistribution. The model predicts water table level and soil moisture. Water extraction may also be modeled. The model predicted both water table levels and soil moisture with reasonable accuracy over the the three year period modeled.Water Resources Research CenterKnoch, Brian C.; Larson, Curtis L.; Slack, Donald C.. (1983). Modeling Direct Recharge of Surficial Aquifers. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/92892
Effects of Drainage Projects on Surface Runoff from Small Depressional Watersheds in the North Central Region
No full textSurface runoff from small watersheds characterized by numerous depressions was studied statistically and by use of a special purpose watershed model. The statistical analyses illustrated the possible magnitude of the storage effect exhibited by lakes, marshes and other depressions. Because of data limitations statistical techniques could not be used to examine the effects on flood runoff of draining these same areas. The model, described in the Bulletin, represents the process of snowmelt, infiltration, soil moisture storage, evapotranspiration, subsurface and surface runoff for four different land drainage conditions, with or without channel development. Application of the model to two small watersheds in Jackson County, Minnesota indicated that drainage development increases annual runoff, storm runoff and peak discharge. The physical characteristics of the main water course in the watershed was the major factor influencing peak discharge at the watershed outlet. Examination of annual flood flows on the Minnesota River at Mankato suggests that downstream effects of drainage development on large watersheds are much less than indicated by this study on small watersheds. Downstream effects and flooding within a watershed are discussed in general terms in the Bulletin.Water Resources Research CenterMoore, Ian D.; Larson, Curtis L.. (1979). Effects of Drainage Projects on Surface Runoff from Small Depressional Watersheds in the North Central Region. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/91412
Numerical Routing of Flood Hydrographs through Open Channel Junctions
No full textThe study was concerned with numerical routing of flood hydrographs through open channel junctions. An open channel junction with a main channel above and below plus a branch channel were constructed in the laboratory.
All channels were rectangular in shape, but varied in size. Facilities and procedures for supplying hvdrographs to the two channels above the junction were developed. Provision was made for measuring both inflow and outflow hydrographs and also flow depths at selected points in the three channels. A total of 14 experiments were conducted with various combinations of input hydrographs in terms of magnitude and relative timing. Unsteady flow conditions (depth, velocity and discharge) in the three channels were calculated at calculated at 5-ft. length increments and 1-sec. time increments, using the method of explicit finite differences applied to the characteristic equations. A procedure for calculating unsteady flow backwater effects in either or both of the upstream channels was developed and utilized as an integral part
of the routing method. The junction routing procedure appears to be fairly general, having been applied in a situation where the channels above and below the junction are at different size, slope and elevation. In particular, it was shown that unsteady flow backwater effects can be represented in the method of explicit finite differences applied to the characteristic equations. Some error can be expected in any numerical method, as well as in all measurements. Due to the measurement error cited above, the amount of error attributable to the routing method cannot be determined. It appears to be on the order of 6 percent, but could be less than this amount.Water Resources Research CenterBowers, C. Edward; Larson, Curtis L.; Wei, Tsong C.. (1971). Numerical Routing of Flood Hydrographs through Open Channel Junctions. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/91893
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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