1,720,955 research outputs found
Evaluierung von Algorithmen zur Segmentierung von Lymphknoten in CT Datensätzen
No full textDie Untersuchung der Größe und Form von Lymphknoten spielt in der Diagnostik und Verlaufskontrolle von Krebspatienten eine wichtige Rolle. Für diese Untersuchung müssen die Lymphknoten in Computertomographie (CT) Datensätzen segmentiert werden. Die manuelle Segmentierung ist zeitaufwändig und fehleranfällig. Für eine präzise Segmentierung von Lymphknoten sind automatische Segmentierungsverfahren erwünscht. In der Literatur werden einige vielversprechende Segmentierungsalgorithmen beschrieben. Alle diese Algorithmen haben ihre Vor- und Nachteile. Eine Gegenüberstellung der Algorithmen wird vermisst. In dieser Arbeit werden vier neue automatische Segmentierungsalgorithmen entwickelt. Die Parameter der Verfahren werden optimiert. Anhand Goldstandards von Experten werden im Anschluss diese vier Methoden und Regionen-, modell- und strahlenbasierte Segmentierungsalgorithmen aus der Literatur in Bezug auf die Genauigkeit, Laufzeit und Robustheit evaluiert und gegenübergestellt. Für die Evaluierung steht ein CT-Datensatz zur Verfügung, für den manuelle Segmentierungen von Experten vorliegen. Der Datensatz besteht aus 49 Lymphknoten der Kopf- und Halsregion von Patienten mit Mundhöhlenkarzinomen. Bei der Gegenüberstellung der Algorithmen wurde festgestellt, dass der strahlenbasierte Ansatz, bei dem die Segmentierung unter Berücksichtigung lokaler Gradienteneigenschaften und Intensitätseigenschaften von Lymphknoten mit anschließender globaler Optimierung erfolgt, am besten für die Segmentierung von Lymphknoten geeignet ist. Die Laufzeit der Segmentierung ist mit 8 Sekunden pro Lymphknoten 3-5 fache der anderen Segmentierungsverfahren. Die Segmentierung ist aber sehr präzise. Der durchschnittliche DSC beträgt 0.80. Bei der Initialisierung mit unterschiedlichen Saatpunkten ist die Methode sehr robust. Bei der Segmentierung von vergrößerten Lymphknoten beträgt der durchschnittliche DSC 0.86, bei der Segmentierung von nekrotischen Lymphknoten 0.81. Anhand von automatischen Segmentierungsalgorithmen können Lymphknoten erfolgreich segmentiert werden. Die Ergebnisse der Segmentierung können z.B. für die dreidimensionale Visualisierung, Verlaufskontrolle von Krebspatienten oder Operationsplanung weiterverarbeitet werden.The assessment of the size and shape of lymph nodes plays a crucial role to diagnose and monitor cancer patients. The assessment is conducted by the segmentation of lymph nodes using computed tomography (CT) data sets. Yet the manual segmentation methods are perceived as time-consuming and errorprone. Therefore there is a need for an automatic segmentation method for an efficient and accurate assessment. In the literature there are several promising segmentation algorithms. Even though the algorithms' advantages and disadvantages have been pointed out by various studies, there is a lack of comprehensive evaluation on these algorithms to optimize overall assessment process. To conduct such a study, initially, four new automatic segmentation algorithms have been developed. Later the parameters of the processes are optimized. Finally, these four methods, along with various region-, model-, and ray-based segmentation algorithms from the available literature, have been evaluated and compared with gold standards of the experts in terms of accuracy, runtime and robustness. For the benchmark, a CT data set with manual segmentations of experts is utilized. The data set consists of 49 lymph nodes from head and neck region of patients with oral cancer. By the comparison of the algorithms, it has been found out that the ray-based approach, which takes the local gradient properties and intensity characteristics of lymph nodes in account, followed by a global optimization, is best suited for the segmentation of lymph nodes. Even though, the run-time of this algorithm is 3-5 times slower than the other segmentation methods by 8 seconds per lymph node, the results of the segmentation are quite accurate. The average DSC is 0.80. The method is very robust during initialization with different seed points, as well. Enlarged lymph nodes can be segmented with an average DSC of 0.86, whereas during the segmentation necrotic lymph nodes, the average DSC is 0.81. On the basis of automatic segmentation algorithms, lymph nodes can be segmented effectively. The results of the segmentation can be further processed, e.g. for the three-dimensional visualization, following up on cancer patients or surgical planning
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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