1,720,973 research outputs found
Suivi, par imagerie NOAA-AVHRR, de l'état hydrique de peuplements de conifères du bassin du fleuve Mackenzie (Territoires du Nord-Ouest) dans une perspective de prévision du danger d'incendie de forêt
No full textIn Canada, forest fire hazard and fire behavior are evaluated on a daily basis by the Canadian Forest Fire Danger Rating System (CFFDRS). One of the inputs into this system is the foliar moisture content which is calculated indirectly from elevation, latitude, longitude and date. To investigate the potential applicability of satellite remote sensing to follow this variable, the foliar moisture content was measured in situ with samples of needles taken weekly during the 1994 forest fire season from white spruce, black spruce and jack pine stands located on seven sites along the Mackenzie River (Northwest Territories). The foliar moisture content measurements were then expressed in relation to the normalized difference vegetation index (NDVI) and the difference between surface and air temperature (Ts-Ta), derived respectively from optical and thermal NOAA-AVHRR images acquired on the same dates as the foliar moisture content measurements. In all cases, the estimated foliar moisture content values obtained from the satellite data were better than those derived from the CFFDRS."--Résumé abrégé par UMI
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
Estimating DBH with iPad Pro LiDAR in Boreal Forests: methodological considerations and a case study in natural boreal forests
Full text linkDiameter at Breast Height (DBH) is the measure of the diameter of a tree stem 1.3
meters above the ground. DBH is a key variable measured in Forest Resource
Inventories (FRIs) and is traditionally measured manually, which is labour-intensive.
The 2020 Apple iPad Pro 12th Generation is a lightweight, consumer-level tablet with an
integrated LiDAR scanner with a maximum range of 5 m and a positional accuracy of
±1 cm. The overall objective was to examine the feasibility of estimating DBH in boreal
forests with iPad Pro LiDAR. A scoping study was conducted in a plantation forest
(48.37°N, 89.39°W) near Thunder Bay, ON, Canada, with the specific objective of
determining an optimal method for DBH estimation with the iPad Pro. Different
combinations of scanning methods (i.e., circular, figure-8, transect), numbers of stem
cross-sections (i.e., one or five), sizes of stem cross-sections (i.e., 4 or 10 cm), and curvefitting formulas (i.e., Pratt’s circle fit, Taubin’s circle fit, Taubin’s ellipse fit, Szpak’s
ellipse fit) were tested to identify the combination producing the most accurate
estimates of DBH. The optimal method was the circular scanning pattern with a single 4
cm cross-section and a combination of circle- and ellipse-fitting formulas (RMSE = 1.1
cm; 6.2%). The second specific objective was to determine the accuracy of DBH values
estimated with the optimal method in natural boreal forests. DBH was estimated for 133
trees on 15 sites in northern Ontario, Canada, representing a range of natural boreal
forest site conditions. A secondary objective was to determine if the tested stand- (i.e.,
species composition, age, density, understory density) or tree-level attributes (i.e.,
species, actual DBH) significantly impacted the accuracy of estimated DBH values. An
RMSE of 1.5 cm (8.6%) was achieved. Estimated DBH was within 1 cm of actual DBH
for 78 of 133 (59%) measured trees. Stand age had a large effect (> 0.15) on the accuracy
of estimated DBH values, while density, understory density, and actual DBH had
moderate effects (0.05-0.15). In both studies, Inertial Measurement Unit (IMU) and
positional accuracy errors with the iPad Pro LiDAR scanner limited the accuracy of
DBH estimates. Future studies should incorporate a greater number of natural boreal
forest sites to better understand the impacts of different stand and tree attributes on the
accuracy of estimated DBH values. Future studies should also compare the accuracy of
DBH values estimated from the iPad Pro and those estimated from traditional MLS and
TLS for the same sites to identify the trade-off between device cost, device size, and
accuracy. However, the scanning range of the device limits the variables that can be
estimated from LiDAR data, rendering it unsuitable for use in FRIs until the scanning
range is improved
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
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