1,720,989 research outputs found
Using Advanced Geometric Models in Image Matching with High Resolution Space Images
No full textHigh resolution Digital Terrain Models (DTMs), suita-ble for geomorphological studies of planets and aster-oids, are today among the main scientific goals of space missions. In the last decades, the great progress in high-resolution imaging of planetary surfaces (with ground-sample-distance that can reach 25 cm/pixel) finds two significant examples in the High Resolution Imaging Science Experiment (HiRISE) on Mars Re-connaissance Orbiter, and in the NAC of the Lunar Reconnaissance Orbiter Camera (LROC) on LRO. These images have provided the widest data-volume ever obtained before from any space mission and are characterized by strong potentialities associated with their astonishing capability of acquire details and fea-tures on the planetary surfaces.
The process for deriving DTMs starting from these raw data is very complex because it has to answer to two main requirements: operate very accurately and work with extremely large data volumes.
Nowadays the most important institutes involved in the planetary mapping are working on developing strategies to fulfil these requests. Despite the introduc-tion of a series of new algorithms for image matching (e.g. the Semi Global Matching: [1]) that yield superior results especially in qualitative terms (smooth and con-tinuous surfaces) and in terms of processing time, the common trend in the planetary-photogrammetry field stays in opting for the established area-based tech-niques and the efforts are more to improving each sin-gle phase of the photogrammetric process (from the image pre-processing stage to the final interpolation of the DTMs).
In this context, the Dense Matcher software (DM) developed at University of Parma has been recently optimized to cope with very high resolution images provided by the most recent missions (LROC NAC and HiRISE) putting the efforts mainly at the correlation phase and at the improvement of the process automa-tion.
In order to improve the performance of the software, a new image correlation code based on advanced Least Squares Matching (LSM) algorithms has been devel-oped.
Perspective changes due to terrain morphology are difficult to accommodate by an area-based stereo cor-relator. The solution has been the use of an iterative algorithm to adapt the correlation window with differ-ent shape functions. Many authors [2] found that the use of a simplified shape function leads to lower com-putational efforts but provides lower accuracy when significant changing in the terrain curvature occurs. Also Bethmann [3] showed that using different shape functions to model the geometric transformation in LSM can bring higher accuracy and solve, in some cases, numerical problems like pixel-locking. In this context, the new DM software uses, rather than the common affine transformation, alternative functional models in the geometrical transformation involved dur-ing LSM to handle perspective differences.
At the same time, working with orbital-space images, usually means to be able to manage large amount of data. Due to that, in order to guarantee good computa-tional performances, efforts have been put in the opti-mization of the processes developing new strategies (grid-matching and tile approach).
Since the stereo-recontruction is strongly correlated to the quality of the image-correlation process (that in many cases can produce outliers and mis-matches) leading to uncorrected interpretations of the topogra-phy, a comparison between uncorrelated data (that don’t participate in the generation of the DTM ) as the laser height points can be used to assess the effective height resolution and the exterior quality (accuracy) of the photogrammetric product.
The paper first describes the main features of the optimized version of Dense Matcher, with particular regard to the mathematical model implemented in the Least Squares Matching. Then, the performance of the image correlation kernel of the program is evaluated through comparisons with DTMs generated by other well established software like Socet Set by Bae System and Ames Stereo Pipeline (NASA) on HiRISE stereo pairs. Finally a comparison is also made with the DTMs produced on NAC stereo-pairs by the Vicar software by DLR (German Aerospace Center), as well as against the LOLA altimeter tracks.
The results look very promising and represent a concrete proof of the capability of Dense Matcher in dealing with two of the most significant examples of high resolution orbital imaging: HiRISE images and the ones acquired by NAC
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
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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