1,720,959 research outputs found
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
양전자단층영상의 정량성 강화를 위한 영상 동질화 연구
Get PDF학위논문(박사) -- 서울대학교대학원 : 의과대학 의학과, 2023. 2. 김상은.Positron emission tomography (PET) imaging has the advantage of quantifying molecular processing during imaging. However, quantification of PET imaging could be affected at any step of the imaging process. Different PET scanners and image reconstruction methods significantly influence the quantification of PET imaging. In this study, PET scanners in South Korea were investigated to evaluate differences in performance using the NEMA/IEC PET phantom and recovery coefficients (RCs).
Quantification requires harmonization according to different PET scanners or reconstruction methods. Conventionally, harmonization is achieved using the NEMA/IEC PET phantom, comprising different sizes of spheres with the same internal radioactivity. RC curves were drawn from different sizes of spheres and these RC curves from different PET scanners were fitted via Gaussian-filtering (GF) of images. This process induced image smoothing, which could distort the true value and differences in values within PET imaging. Under certain conditions of a fixed size of the measurement target, a different approach of harmonization could be used. Unlike the NEMA/IEC PET phantom, a custom phantom configured with the same size for a target with different radioactivity could be used for harmonization. In this study, a custom-made phantom with 4 cylindrical inserts with a 20-mm internal diameter was used to harmonize 18F-fluorodeoxyglucose (FDG) PET images of stage Ib and Ic lung adenocarcinoma obtained at 3 hospitals with 5 different PET scanners. Data distribution and recurrence as outcomes were used to compare the observed effect before and after harmonization with the custom phantom or conventional method. Although there was no significant difference in other clinical factors, before harmonization, the maximum standardized uptake value (SUVmax) of lung cancer lesions showed a significant difference according to PET scanner type. After custom phantom harmonization, the SUVmax of lung cancer lesions showed no significant difference according to PET scanner type. Even after harmonization with the conventional method with GF, there were still differences in SUVmax among scanners. To discriminate recurrence by the SUVmax of lung cancer lesions, custom phantom harmonized data showed an increased area under the receiver-operating characteristic curve compared to data acquired before harmonization or GF-filtered data. Therefore, under specific conditions in which the measurement target size is fixed, custom phantom harmonization could be an alternative method.
Lastly, texture analysis of PET is known to be affected by various conditions of PET scanners and reconstruction methods. Using the normal liver on lung cancer patients FDG PET images as the reference organ, batch effects of different PET scanners on texture parameters and the effect of GF on texture parameters were assessed. Data-driven harmonization with ComBat on texture parameters was performed to harmonize the texture parameters of PET images. Principal component analysis and calculation of variance showed the presence of batch effect related to the different PET scanners or GF effect on FDG PET images. ComBat harmonization significantly decreased the batch effects and variance on texture parameters of normal liver. FDG PET Texture parameters from ComBat harzmonization can predict EGFR mutation status of lung cancer unless the raw texture parameters could not be predicted. Data-driven harmonization via ComBat could be promising for multi-center PET radiomics.양전자방출단층촬영은 인체의 생리화학적 정보를 영상화여 이를 정량화 할 수 있는 최신 의료기기이다. 그러나 다양한 양전자방출단층촬영 스캐너의 종류 및 영상후처리 기법으로 인하여, 양전자방출단층촬영의 정량값의 측정오차가 발생할 수 있다. 이러한 양전자방출단층촬영의 정량값에 대한 기기별 및 영상후처리별 차이에 대한 보정으로서 최근 영상 동질화 방법에 대하여 관심이 증가하고 있다. 기존에 널리 쓰이는 영상 동질화 방법은 NEMA/IEC PET 팬텀을 사용하는 것으로, 이 팬텀 안에는 서로 다른 크기의 구형의 공간이 있으며, 이 안에 같은 양의 방사성물질을 채워 넣은 후 양전자방출단층촬영 스캐너에서 촬영한 뒤에, 이를 통해 각 크기별 구형으로부터 구한 RC 값을 구하게 된다. 영상에 가우시안 필터를 통하여, 서로 다른 스캐너에서 구한 이 RC값이 최적으로 동질화 되게 하는데, 이러한 가우시안 필터링은 필연적으로 영상을 평활화(smoothing)하게 되며, 영상의 질을 낮추게 된다. 이러한 과정 속에서 양전자방출단층촬영에서 측정된 참값 및 각 참값 간의 차이는 왜곡되게 된다. 만일, 양전자방출단층촬영에서 측정하고자 하는 표적의 크기가 일정하게 정해져 있으며, 표준섭취계수(Standard Uptake Value, SUV)를 측정하는 상황이라면, 다른 방법의 영상동질화 방법을 고려할 수 있다. NEMA/IEC PET 팬텀과는 다르게, 표적의 크기와 비슷한 크기의 구형의 팬텀에, 서로 다른 농도의 방사성물질을 채우는 팬텀을 맞춤 제작을 하였고, 이를 스캔하여 영상에서 측정된 측정값과 이미 알고있는 팬텀내의 방사능의 값을 이용하여 선형 피팅식을 구한 후, 각 스캐너별로 측정한 병변의 SUVmax 을 이 선형 피팅식을 변환시킨다면, 가우시안 필터링으로 인한 영상 및 측정값의 왜곡 없이 영상 동질화가 가능할 수 있다. 본 연구에서는 국내 다수의 양전자방출단층촬영 스캐너에 대하여, 국제 인증 NEMA/IEC PET 팬텀을 사용하여 recovery coefficient(RC)값을 구하는 방법으로 성능의 차이에 대하여 조사하였다. 또한, 3개의 병원 및 5개의 양전자방출단층촬영기에서 얻은 폐선암 Ib 및 Ic병기의 환자들의 영상에 대하여, 내부 직경이 2cm으로 동일한 4개의 실린더를 가진 맞춤 제작 팬텀을 이용하여 영상 동질화를 시행하였다. 폐암의 당대사 정도를 측정한 SUVmax 값의 분포와 폐암의 재발을 결과변수로 하여, 재발의 정도를 SUVmax 로 판별할 수 있는 지에 대하여 영상 동질화 전의 데이터, 맞춤팬텀으로 동질화한 데이터, 및 기존 NEMA/IEC PET팬텀으로 동질화한 데이터간의 결과 값을 비교하였다. 촬영 기기별 환자의 임상적 요인의 차이는 유의한 것이 없었으나, 영상동질화 전의 SUVmax 값은 기기별로 유의한 차이를 보였다. 맞춤팬텀으로 동질화 한 경우, 기기별 SUVmax 값의 유의한 차이는 없었으며, NEMA/IEC PET팬텀으로 가우시안 필터링한 경우 기기별 SUVmax 값의 유의한 차이는 지속되었다. 폐암 재발에 대한 SUVmax 의 설명력은 맞춤팬텀으로 동질한 경우 그 설명력이 가장 높았다. 따라서, 이 연구와 같이, 측정하고자 하는 병변의 크기가 일정한 경우에 있어서, 병변의 크기와 유사한 맞춤 팬텀을 이용한 영상동질화 방법을 도입할 수 있을 것으로 보인다.
양전자방출단층촬영 영상의 텍스쳐 분석 또한 다양한 스캐너의 종류 및 영상후처리 기법에 대하여 영향을 받을 수 있음이 알려져 있는데, 본 연구에서는 질환이 없는 정상 간을 레퍼런스로 이용하여, 서로 다른 스캐너별 batch effect가 있는지 확인을 하였고, SUVmax 를 보정하기 위한 NEMA/IEC PET 팬텀에서 얻은 가우시안 필터링이 텍스쳐 파라미터에 미치는 영향을 확인하였으며, 데이터기반 영상동질화 방법의 하나인 ComBat을 이용하여 텍스쳐 파라미터의 영상동질화 가능성에 대하여 살펴보았다.Chapter 1. Introduction １
1.1. Study Background １
1.2. Purpose of Research ４
Chapter 2. Materials and Methods ６
2.1 Survey of PET/CT quality in South Korea ６
2.2 PET Harmonization with Custom-made Phantom ７
2.3 PET Radiomics and Harmonization １４
2.4 Statistical analysis １９
2.5 Ethical Considerations １９
Chapter 3. Results ２０
3.1 Survey of PET/CT quality in South Korea ２０
3.2 PET Harmonization with Phantom ２５
Chapter 4. Discussion ６３
Chapter 5. Conclusion ６９
Bibliography ７０
국문 초록 ７４박
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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