1,720,972 research outputs found
Towards Autonomous Navigation in Endovascular Interventions
Get PDFCardiovascular Diseases (CVDs) remain the leading cause of global mortality, with minimally invasive treatment options offered through endovascular interventions. However, the precision and adaptability of current robotic systems for endovascular navigation are impeded by constraints such as heuristic control, limited autonomy, and the absence of haptic feedback. In this thesis, an integrated AI-driven framework is presented to enable autonomous guidewire navigation within complex vascular environments, addressing critical limitations in data availability, simulation fidelity, and navigational accuracy.
A high-fidelity, real-time simulation platform, CathSim, is introduced for Reinforcement Learning (RL)-based catheter navigation, featuring anatomically accurate vascular models and contact dynamics. To leverage the multimodal data generated by CathSim, the Expert Navigation Network is developed—an RL-based policy integrating visual, kinematic, and force feedback for autonomous tool control. To address data scarcity, an open-source, bi-planar fluoroscopic dataset, Guide3D, is proposed, comprising over 8,700 annotated images for 3D guidewire reconstruction. Finally, a transformer-based model, SplineFormer, is proposed, which directly predicts guidewire geometry as continuous B-spline parameters, enabling interpretable, real-time navigation.
The findings demonstrate that the integration of high-fidelity simulation, multimodal sensory fusion, and geometric modelling significantly enhances autonomous endovascular navigation. CathSim proves effective for training RL algorithms with realistic interactions, while the Expert Navigation Network shows superior performance in complex anatomical structures. Guide3D successfully addresses data scarcity challenges, and SplineFormer achieves high-precision guidewire prediction with improved interpretability. These contributions establish a comprehensive foundation for advancing autonomous endovascular interventions, offering a pathway toward safer and more precise minimally invasive procedures
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
The i²Snake robot for endoscopic surgery
Get PDFMinimally invasive surgery and more specifically endoscopic surgery is a surgical technique aiming to improve patient treatment and recovery by using natural orifices rather than incisions. However, this is at the cost of increased complexity for the surgeon and limits the number of procedures that can be performed. The recent introduction of robotic technology in the operating room has allowed to overcome most of the challenges faced during minimally invasive surgery, but further research needs to be done to develop robotic endoscopy. This thesis introduces a novel endoscopic robot called the i²Snake, an acronym for intuitive, imaging, sensing, navigated, and kinetically enhanced. The i²Snake is a snake-like robot with a fully actuated body and four instrument channels: 1x for a camera with light, 2x for a pair of robotic instruments and 1x for suction/irrigation. Several aspects of the design and control of the system are tackled in this thesis. Firstly, the state-of-the-art in medical robotics is studied in detail to determine the current trends and identify the existing gaps and needs for such robotic platforms. This is followed by a chapter on the mechanical design of the i²Snake. The design proposes an optimized rolling-joint to improve stability and joint range. The robot also uses a novel tendon routing to minimize cross-talk between joints and to allow formation of complex configurations such as S-shapes. The third chapter focuses on the design of the robotic instruments. This is accomplished by using recorded surgical trajectories combined with a genetic algorithm to automatically design an optimized pair of instruments. The fourth and fifth chapters focus on teleoperation and navigation to ensure intuitive full-body shape control and navigation. Finally, the last chapter discusses the operating room ergonomics and introduces novel features for safe and intuitive manipulation of the robotic platform.Open Acces
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
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