1,720,957 research outputs found
Data-driven patient-specific models supporting decision making with application to atherosclerotic plaque analysis
Full text link(English) This thesis advances finite element-based tools to improve atherosclerosis analysis by addressing current computational limitations.
Atherosclerosis, the leading cause of ischaemic heart attacks, imposes a significant social and economic burden (estimated at around $1 trillion worldwide by 2030).
In this disease, patients develop plaques from lipid accumulation in the arteries and these plaques can be prone to rupture or stable.
Differentiating between these types is essential for effective clinical risk management.
Fast, accurate, and robust computational methods can streamline the clinical pipeline and ultimately may help to assess atherosclerotic analysis.
We use Finite Element Method (FEM) to simulate stress in atherosclerotic sections, as peak stress plays a key role in assessing
rupture risk. Our methods are based on unfitted FEM, which simplify mesh generation, save computational and pre-processing time.
Importantly, these methods can work directly on voxelized data such as medical images.
The proposed unfitted approaches achieve accuracy within 5 % of that attained by classical fitted approaches and commercial software, for both linear and non-linear cases.
Moreover, these methods incorporate a flexible and realistic boundary conditions that account for the influence of surrounding tissues.
We also developed an Adaptive Model Reduction (AMR) technique based on a linear hypothesis, serving as a preliminary step toward creating fast surrogate models for near-real-time simulations.
Validation experiments demonstrate that AMR decrease computational resource usage by over 70 % while maintaining an accuracy within a 9 % error margin compared to high-fidelity models.
Finally, preliminary results indicate that using Topological Data Analysis (TDA) to build interpretable Machine Learning (ML) models can effectively assesses plaque rupture risk.
Early experiments yield a classification accuracy of approximately 75 %, a performance comparable to established radiomics approaches.
Overall, this doctoral work demonstrates that combining advanced FEMs with interpretable ML may provides nuanced insights into atherosclerotic plaque assessment.
Future research should address potential limitations such as data variability and scalability to enable broader implementation of these computational techniques in clinical practice.(Català) Aquesta tesi avança en eines basades en elements finits per millorar l'anàlisi de l'aterosclerosi abordant les limitacions computacionals actuals.
L'aterosclerosi, la principal causa d'atacs cardíacs isquèmics, imposa una càrrega social i econòmica important (estimada al voltant d'1 bilió de dòlars a tot el món el 2030).
En aquesta malaltia, els pacients desenvolupen plaques per acumulació de lípids a les artèries i aquestes plaques poden ser propenses a trencar-se o estables.
Diferenciar entre aquests tipus és essencial per a una gestió eficaç del risc clínic.
Els mètodes computacionals ràpids, precisos i robustos poden agilitzar el pipeline clínic i, en última instància, poden ajudar a avaluar l'anàlisi ateroscleròtica.
Utilitzem el mètode dels elements finits (FEM) per simular l'estrès en seccions ateroscleròtiques, ja que l'estrès màxim juga un paper clau en l'avaluació risc de ruptura.
Els nostres mètodes es basen en FEM no ajustats, que simplifiquen la generació de malles, estalvien temps computacional i de preprocessament.
És important destacar que aquests mètodes poden funcionar directament en dades voxelitzades, com ara imatges mèdiques.
Els enfocaments no ajustats proposats aconsegueixen una precisió del 5% de la que aconsegueixen els enfocaments ajustats clàssics i el programari comercial, tant per a casos lineals com no lineals.
A més, aquests mètodes incorporen condicions de contorn flexibles i realistes que expliquen la influència dels teixits circumdants.
També hem desenvolupat una tècnica de reducció de models adaptatius (AMR) basada en una hipòtesi lineal, que serveix com a pas preliminar cap a la creació de models substituts ràpids per a simulacions gairebé en temps real.
Els experiments de validació demostren que l'AMR disminueix l'ús de recursos computacionals en més d'un 70% mentre manté una precisió dins d'un marge d'error del 9% en comparació amb els models d'alta fidelitat. Finalment, els resultats preliminars indiquen que l'ús de l'anàlisi de dades topològiques (TDA) per construir models interpretables d'aprenentatge automàtic (ML) pot avaluar eficaçment el risc de ruptura de la placa.
Els primers experiments produeixen una precisió de classificació d'aproximadament el 75%, un rendiment comparable als enfocaments radiòmics establerts.
En general, aquest treball doctoral demostra que la combinació de FEM avançats amb ML interpretable pot proporcionar informació matisada sobre l'avaluació de la placa ateroscleròtica.
La investigació futura hauria d'abordar les limitacions potencials com la variabilitat i l'escalabilitat de les dades per permetre una implementació més àmplia d'aquestes tècniques computacionals en la pràctica clínica.(Español) Esta tesis avanza en las herramientas basadas en elementos finitos para mejorar el análisis de la aterosclerosis abordando las limitaciones computacionales actuales.
La aterosclerosis, principal causa de infartos isquémicos, impone una importante carga social y económica (estimada en alrededor de 1 billón de dólares en todo el mundo para 2030).
En esta enfermedad, los pacientes desarrollan placas por acumulación de lípidos en las arterias y estas placas pueden ser propensas a la rotura o estables.
Diferenciar entre estos tipos es esencial para una gestión clínica eficaz del riesgo.
Unos métodos computacionales rápidos, precisos y robustos pueden agilizar el proceso clínico y, en última instancia, ayudar a evaluar el análisis aterosclerótico.
Utilizamos el método de los elementos finitos (FEM) para simular la tensión en secciones ateroscleróticas, ya que la tensión máxima desempeña un papel clave en la evaluación del riesgo de rotura.
Nuestros métodos se basan en el FEM no ajustado, que simplifica la generación de mallas y ahorra tiempo computacional y de preprocesado.
Además, estos métodos pueden trabajar directamente con datos voxelizados, como las imágenes médicas.
Los enfoques no ajustados propuestos alcanzan una precisión inferior en un 5% a la lograda por los enfoques ajustados clásicos y el software comercial, tanto para casos lineales como no lineales.
Además, estos métodos incorporan unas condiciones de contorno flexibles y realistas que tienen en cuenta la influencia de los tejidos circundantes.
También desarrollamos una técnica de reducción adaptativa de modelos (AMR) basada en una hipótesis lineal, que sirve como paso preliminar hacia la creación de modelos sustitutos rápidos para simulaciones en tiempo casi real.
Los experimentos de validación demuestran que la AMR disminuye el uso de recursos computacionales en más de un 70 %, al tiempo que mantiene una precisión dentro de un margen de error del 9 % en comparación con los modelos de alta fidelidad.
Por último, los resultados preliminares indican que el uso del análisis topológico de datos (TDA) para construir modelos interpretables de aprendizaje automático (ML) puede evaluar eficazmente el riesgo de rotura de la placa.
Los primeros experimentos arrojan una precisión de clasificación de aproximadamente el 75 %, un rendimiento comparable al de los enfoques radiómicos establecidos.
En general, este trabajo de doctorado demuestra que la combinación de FEM avanzados con ML interpretables puede proporcionar conocimientos matizados sobre la evaluación de la placa aterosclerótica.
La investigación futura debe abordar las posibles limitaciones, como la variabilidad de los datos y la escalabilidad, para permitir una aplicación más amplia de estas técnicas computacionales en la práctica clínica.DOCTORAT EN ENGINYERIA CIVIL (Pla 2012
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
- …
