1,720,955 research outputs found
Characterization of Mediterranean forest formations using ground-based LiDAR systems
No full textAccurate forest structure monitoring is key to understanding ecosystem dynamics and informing
management. Advances in remote and proximal sensing, especially LiDAR (Light Detection and
Ranging), have transformed forest inventories. Terrestrial Laser Scanning (TLS) and Mobile Laser
Scanning (MLS) now enable precise, non-invasive 3D capture of canopy, stem, and understory
features.
A significant challenge in using LiDAR for forestry is distinguishing woody from non-woody
elements (leaves, shrubs, ground vegetation), which is essential for estimating structure and biomass.
Over the past two decades, various methods have aimed to address this.
This dissertation introduces a workflow for analyzing TLS and MLS point clouds, focusing on the
separation of woody and non-woody components. The method combines voxelization, ground
filtering, and clustering algorithms into a streamlined process. Trials were conducted in
Mediterranean forests in Sardinia, Italy, using both TLS and MLS devices. These tools were assessed
for their ability to capture vertical structure and understory detail.
Results showed high classification accuracy. TLS units performed better in dense forests due to
superior resolution, while MLS devices were effective in simpler contexts, offering faster data
collection.
A key contribution is the development of an R software package, Point cloud Interactive Computation
(PiC), which automates the workflow. PiC processes raw LiDAR data through each stage, producing
voxelized outputs, filtered ground layers, and classified components. It was tested on two forest plots,
showing reliable performance across different sensors and computing setups.
Despite promising results, challenges remain in complex forests with varied species, crown shapes,
or dense understory. Future work should enhance the workflow's adaptability and test it in nonMediterranean ecosystems to assess broader applicability.
This research highlights the value of integrating TLS and MLS with analytical tools for forest
monitoring, offering insights to support sustainable forest management and ecological modelingForests play important ecological, economic, and social roles, contributing to carbon sequestration, biodiversity conservation, and sustainable resource management. Accurate monitoring and modeling of forest structure is critical to improving our understanding of ecosystem dynamics and guiding forest management decisions. Recent advances in remote and proximal sensing technologies, particularly LiDAR (Light Detection and Ranging), have revolutionized forest inventory techniques. Among these, Terrestrial Laser Scanning (TLS) and Mobile Laser Scanning (MLS) have emerged as key tools for acquiring detailed three-dimensional data on forest canopy, stem, and understory vegetation. These technologies provide non-invasive, highly accurate measurements of forest parameters.
One major challenge in forestry applications of LiDAR is the accurate separation of woody material (trunks, branches) from non-woody components (leaves, shrubs, and ground vegetation). This distinction is essential for estimating key forest metrics, including structural attributes and biomass distribution. Over the past two decades, various methodologies have been developed to address this issue.
This dissertation presents a workflow for analyzing TLS and MLS point clouds, with a specific focus on accurately separating woody and non-woody components. The proposed methodology integrates voxelization, ground filtering, and clustering algorithms, providing a streamlined approach for processing LiDAR data. The methodology was tested in Mediterranean forest contexts in Sardinia, Italy. Data collection involved both fixed-station TLS devices and handheld MLS devices. These instruments were evaluated based on their ability to capture canopy structure and understory complexity.
Results demonstrated that the workflow achieved high classification accuracy. Fixed-station TLS instruments outperformed handheld devices in dense and complex forest environments due to their higher resolution and data quality. However, the MLS proved effective in simpler forest settings, offering the advantage of rapid data acquisition.
An important aspect of the study was the development of a software package for the "R" statistical analysis platform, called Point cloud Interactive Computation (PiC), designed to automate the proposed workflow. The PiC package processes raw LiDAR point clouds step-by-step, generating outputs at each stage, including voxelized data, ground-separated layers, and classified woody/non-woody components. The software was also tested on two forest plots. The results confirmed the versatility and ease of use of the package, which efficiently and consistently processed data from a TLS and MLS, regardless of the type of hardware used to run the software.
Despite the promising results, challenges remain in applying the methodology to highly heterogeneous forests, such as those with diverse tree species, complex crown geometries, and dense understory vegetation. Future research should aim to improve the robustness of the workflow by incorporating additional features. Furthermore, testing this methodology in non-Mediterranean ecosystems would provide insights into its broader applicability and limitations, adapting it to account for variations in canopy architecture, tree species composition, and understory density.
This work underscores the potential of integrating TLS and MLS technologies with advanced analytical workflows in forest monitoring. The insights gained from this research can contribute to more effective forest management practices and enhanced ecological modeling in a wide range of forest environment
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
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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