1,720,969 research outputs found
Evaluating the use of uncertainty visualization for exploratory analysis of land cover change: a qualitative expert user study
No full textExtensive research on geodata uncertainty has been conducted in the past decades, mostly related to modeling, quantifying, and communicating uncertainty. But findings on if and how users can incorporate this information into spatial analyses are still rare. In this paper we address these questions with a focus on land cover change analysis. We conducted semi-structured interviews with three expert groups dealing with change analysis in the fields of climate research, urban development, and vegetation monitoring. During the interviews we used a software prototype to show change scenarios that the experts had analyzed before, extended by visual depiction of uncertainty related to land cover change.This paper describes the study, summarizes results, and discusses findings as well as the study method. Participants came up with several ideas for applications that could be supported by uncertainty, for example, identification of erroneous change, description of change detection algorithm characteristics, or optimization of change detection parameters. Regarding the aspect of reasoning with uncertainty in land cover change data the interviewees saw potential in better-informed hypotheses and insights about change. Communication of uncertainty information to users was seen as critical, depending on the users’ role and expertize. We judge semi-structured interviews to be suitable for the purpose of this study and emphasize the potential of qualitative methods (workshops, focus groups etc.) for future uncertainty visualization studies
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
Changes of Boreal Vegetation in Permafrost Areas of Central Yakutia
No full textMankind influences the vegetation in the northern permafrost areas of Eurasia by its activities,
such as mining, forest clearing and pollution. However man is not the only factor inducing
changes in Siberian boreal conifer forests, forest fires and other natural processes,
e.g. climate change, also have impacts on the vegetation.
In an area besides the Russian river Viluy in Central Yakutia those changes are eminently
evident. The combination the local vegetation and the expansion of the cropped area are
the mainly influencing factors. For this area, which is mainly covered by larch forests and
geomorphological and hydrological very dynamic thermokarst depressions (alases) that
are often filled with water, some approaches to quantify these processes are sampled in
this work to extract tendencies for the whole circumpolar boreal forest belt. Therefore it
has been worked with Landsat-remote-sensing-data and with climate data that were recorded
at a weather station in the study area, which have been analysed thoroughly. The
presented results show the exploration of the extent and possible reasons for the change
of the forest cover
Phenological and spectral optimisation of multi-temporal land use classification
Full text linkFernerkundungsdaten sind eine wichtige Quelle für die Ableitung von Landnutzungsinformationen. Diese Arbeit untersucht die Potentiale zunehmender zeitlicher Verfügbarkeit von optischen Satellitenbildaufnahmen sowie der Integration von phänologischen Beobachtungsdaten für die Optimierung von Landnutzungsklassifkationen. Es wurde eine Methode zur automatisierten Optimierung von spektralen Maßen und Indizes entwickelt, aus welchen anschließend mehrjährige Trennbarkeitsprofile von Feldfrüchten ermittelt werden konnten. Weiterhin wurde ein geostatistisches Modell zur flächenhaften Modellierung von Eintrittsdaten pflanzenphänologischer Phasen entwickelt. Aus der Kombination dieser Ansätze konnten phänologische Zeitfenster für die gezielte Auswahl von Aufnahmezeitpunkten für Klassifikationen aus Satellitenbildzeitreihen abgeleitet werden. Das optimierte multi-temporale Verfahren wird in einem Untersuchungsgebiet in Mitteldeutschland demonstriert und mit einem etablierten Verfahren verglichen.Remote sensing data are an important source for the derivation of land use information. In this work, an optimised classification approach is presented that employs the potentials of increasing temporal availability of optical satellite data and the integration of phenological ground observations. A method for the automated optimisation of spectral indices was developed, which could be used to derive temporal profiles of field crop spectral separability. Further, a geostatistical model for spatial modelling of observations of plant phenological phases was developed. Finally, these approaches are combined to detect phenological time frames for the selection of the most valuable acquisition dates for classification purposes out of dense satellite image time series. The optimised classification framework is demonstrated in a study site in Central Germany and compared to an established multi-temporal classification approach.vorgelegt von Henning Gerstman
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