1,720,958 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
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Directed Shape Morphing of Soft Kirigami Deployables
Get PDFThis study explores deployable structures inspired by nature’s morphogenesis, where biological systems inherently develop complex forms autonomously. Applying these principles, this research proposes a new approach where materials self-organize and morph from two-dimensional to three-dimensional shapes without traditional manufacturing constraints.Deployable structures offer significant advantages in compactness, simplifying storage and transportation, making them particularly valuable in fields like aerospace and biomedicine where tailored, precise forms are crucial. However, the transformation from planar to three-dimensional structures presents substantial challenges due to complex design interdependencies. To address this, the research develops kirigami based structures capable of deploying from a planar to a 3D shapes. Furthermore, these possess the ability of switching between stable states without continuous energy input, enhancing their functionality for various applications. Additionally, the study tackles the inverse design challenge through a novel integration of machine learning, optimizing design parameters for specific functional needs efficiently. This approach not only bridges the gap between static planar manufacturing and dynamic structural functionality but also creates a platform for a more intuitive, equipment-frugal way to tackle deployable systems, setting the stage for future innovations in the field
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Computational Methods in Slender Structures and Soft Robots
Get PDFSlender structures, existing in both natural environments (tendrils) and man-made systems (soft robots), often undergo geometrically nonlinear deformations and dramatic topological changes when subjected to simple boundary conditions or moderate external actuations, which pose extensive challenges to the traditional numerical and analytical methods. This dissertation focuses on the Discrete Differential Geometry (DDG)-based numerical frameworks for simulating the mechanical response in slender structures and soft robots, and makes four major contributions:First, we use a planar rod theory and incorporate Coulomb frictional contact, elastic/inelastic collision with ground, and inertial effects in a physically accurate manner, to simulate the dynamics of shape memory alloy (SMA)-powered soft robots. Our simulations show quantitative agreement when compared against with experiments, suggesting that our numerical approach represents a promising step toward the ultimate goal of a computational framework for soft robotic engineering. We then combine the same planar rod framework with a naive fluid-structure interaction model to perform the swimming of a seastar-inspired soft robot in water.Secondly, we numerically explore the propulsion of bacteria flagella in a low Reynolds fluid. We study the locomotion of a bacteria-inspired soft robot. Our numerical framework uses (i) Discrete Elastic Rods (DER) method to account for the elasticity of soft filament, (ii) Lighthill's Slender Body Theory (LSBT) for the long term hydrodynamic flow by helical flagellum, and (iii) Higdon's model for the hydrodynamics from spherical head. A data-driven approach is later employed to develop a control algorithm such that our flagella-inspired robot can follow a prescribed trajectory only by changing its rotation frequency. Then, to investigate the bundling behavior between two soft helical rods rotating side by side in a viscous fluid, we implement a coupled DER and Regularized Stokeslet Segment (RSS) framework. The contact between two rods is also considered in our numerical tool. A novel bundling behavior between two nearby helical rods is uncovered, whereby the filaments come across each other above a critical angular velocity.Our third contribution is to present a numerical method for both forward physics-based simulations and inverse form-finding problems in elastic gridshells. Our numerical framework on elastic gridshell first decomposes this special structure into multiple one dimensional rods and linkers, which can be performed by the well-established Discrete Elastic Rods (DER) algorithm. A stiffed spring between rods and linkages is later introduced to ensure the bending and twisting coupling at joint area. The inverse form finding problem -- compute the initial planar pattern from a given 3D configuration -- is directly solved by a contact-based procedure, without using any the conventional optimization-based algorithms. Several examples are used to show the effectiveness of the inverse design process.Finally, we compare Kirchhoff rod model, Sadowsky ribbon model, and FvK plate equations, to systematically characterize a group of slender structures, from narrow strip to wide plate. We consider a pre-buckled band under lateral end translation and quantity its supercritical pitchfork bifurcation. The one dimensional anisotropic rod can give a reasonable prediction when the strip is narrow, while fails to capture its width effect. A two dimensional plate approach, on the other hand, accurately anticipates the nonlinear deformations and the critical supercritical pitchfork points for both narrow and wide plates. We finally discuss in detail the issues of traditional one dimensional ribbon models at the inflection points, and then use an extensible ribbon model to bridge the gap between the Kirchhoff rod model and the classical Sadowsky ribbon model
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
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Design, Modeling and Control of Flexible Structures in Robotics Applications
Get PDFFlexible structures play a pivotal role in enabling novel forms of robotic locomotion, manipulation, and medical intervention. This dissertation investigates the design, modeling, and control of flexible structures across increasing geometric complexity—from rods, to rings, to shells—with an emphasis on their integration into robotic systems. First, we examine rod-like geometries inspired by bacterial flagella, where single and bi-flagellated robots leverage helical rod rotation to achieve propulsion in low Reynolds number environments. Second, we present pneumatic ring actuators that generate peristaltic motions for grasping and transporting irregular or soft objects, demonstrating robust manipulation without the need for complex control strategies. Finally, we extend the framework to pneumatic membrane shells for hemostasis applications, coupling soft structures with robotic arms to achieve precise deployment and pressure regulation on bleeding sites. Across all three case studies, we develop physics-based and data-driven models, integrate proprioceptive and external sensing for feedback, and design control strategies that link structural mechanics with task-specific robotic performance. Together, these contributions establish a unified perspective on how flexible structures—ranging from slender rods to curved shells—can be harnessed to expand the functionality, adaptability, and safety of next-generation robotic systems
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
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
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