305,276 research outputs found
River Feshie, Scotland - Geomorphic Change Detection - Example Dataset
No full textA simple Example GCD Dataset illustrating topographic change detection from five years of repeat monitoring of the Feshie from 2003 to 2007. Used in Tutorials (e.g. FIS Error Modelling) and appears in: Wheaton JM, Brasington J, Darby SE, Sear DA, Vericat D‡., and Kasprak A*. 2013. Morphodynamic signatures of braiding mechanisms as expressed through change in sediment storage in a gravel-bed river. Journal of Geophysical Research - Earth Surface. DOI: 10.1002/jgrf.20060. Wheaton JM, Brasington J, Darby SE, Merz JE, Pasternack GB, Sear DA and Vericat D‡. 2010. Linking Geomorphic Changes to Salmonid Habitat at a Scale Relevant to Fish. River Research and Applications.26: 469-486. DOI: 10.1002/rra.1305. . Dataset is from: 700m braided gravel bed river in the Scottish Cairngorm mountains. 5 annual surveys Mix of RTKGPS and Total Station 1m cell resolution Dataset includes raw data to run exercises, as well as full *.gcd projects that can be opened.</span
Analysis of reach-scale elevation distribution in braided rivers: Definition of a new morphologic indicator and estimation of mean quantities
No full textThis work has been carried out within the SMART Joint Doctorate (Science forthe MAnagement of Rivers and theirTidal systems) funded with the support of the Erasmus Mundus programme of the European Union. Data of the Rees River were derived as part of UKNatural Environment Research Council grant (NE/G005427/1) awarded to PI Brasington, along with further support from the NERC Geophysical Equipmen tFacility (Loan 892) and Leverhulme Trust IAF2014-03
Sulphur Creek, California - Geomorphic Change Detection - Example Dataset
No full textA simple Example GCD Dataset illustrating topographic change detection from a single flood event. Used in Tutorials (e.g. DoD Thresholding). Dataset is from 300m of gravel bed river near St. Helena California that underwent a New Year's Eve flood in December 2005. Two surveys (Dec 2015 and Jan 2016) 0.5m cell resolution Surveyed with hybrid of RTKGPS and Total Station</span
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Accounting for uncertainty in DEMs from repeat topographic surveys: improved sediment budgets
No full textRepeat topographic surveys are increasingly becoming more affordable, and possible at higher spatial resolutions and over greater spatial extents. Digital elevation models (DEMs) built from such surveys can be used to produce DEM of Difference (DoD) maps and estimate the net change in storage terms for morphological sediment budgets. While these products are extremely useful for monitoring and geomorphic interpretation, data and model uncertainties render them prone to misinterpretation. Two new methods are presented, which allow for more robust and spatially variable estimation of DEM uncertainties and propagate these forward to evaluate the consequences for estimates of geomorphic change. The first relies on a fuzzy inference system to estimate the spatial variability of elevation uncertainty in individual DEMs while the second approach modifies this estimate on the basis of the spatial coherence of erosion and deposition units. Both techniques allow for probabilistic representation of uncertainty on a cell-by-cell basis and thresholding of the sediment budget at a user-specified confidence interval. The application of these new techniques is illustrated with 5 years of high resolution survey data from a 1 km long braided reach of the River Feshie in the Highlands of Scotland. The reach was found to be consistently degradational, with between 570 and 1970 m3 of net erosion per annum, despite the fact that spatially, deposition covered more surface area than erosion. In the two wetter periods with extensive braid-plain inundation, the uncertainty analysis thresholded at a 95% confidence interval resulted in a larger percentage (57% for 2004-2005 and 59% for 2006-2007) of volumetric change being excluded from the budget than the drier years (24% for 2003-2004 and 31% for 2005-2006). For these data, the new uncertainty analysis is generally more conservative volumetrically than a standard spatially-uniform minimum level of detection analysis, but also produces more plausible and physically meaningful results. The tools are packaged in a wizard-driven Matlab software application available for download with this paper, and can be calibrated and extended for application to any topographic point cloud (x,y,z)
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Educational Outcomes and House Values: A Test of the Value-Added Approach
No full textWe use house price hedonics to compare the extent that homeowners value traditional measures of school quality or the “value added” of schooling. Unlike other studies, we use spatial statistics as an identification strategy. Based on our study of 310 school districts and 77,000 house transactions, we find little support for the value added model. Instead, we find that households consistently value a district’s average proficiency test scores and expenditures. The elasticity of house prices with respect to school expenditures is 0.49 and an increase in test scores by one standard deviation, ceteris paribus, raises house prices by 7.1%.
Public and Private School Competition: The Spatial Education Production Function
No full textSchool vouchers may increase the competition public school districts face. Greater competition may spur public schools to improve student outcomes, which reliably predict labor market productivity and earnings. Previous school competition studies do not use spatial statistics; they fail to incorporate spillovers and the effect of omitted variables into their education production functions. Significant spatial effects are found in all regressions, and spatial statistics improves adjusted R-squared. There seems to be no consistent association between private school attendance rates and public school achievement, or between the number of public school districts in a county and public school performance. Competitive effects, which seem plausible in non-spatial regressions, dissipate when spatial statistics is used. When school inputs appeared statistically significant in non-spatial regressions, the spatial regressions generally made the significance disappear. Poverty appeared to depress reading and writing passage rates, but this effect disappeared in the spatial models.
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