1,721,004 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
The Evolution of the Mechanical Properties of Biodegradable Materials with Respect To Time and Aspect Ratio
No full textBiodegradable materials were widely utilized to reduce waste, particularly in the medical industry where they were preferred over biomaterials due to their biocompatibility with the body, resulting in faster recovery. These biodegradable polymers could either be derived from natural sources like collagen, cellulose, and starch or synthetic polymers made from petroleum. The degradation process of these materials had been extensively documented in literature with regards to molecular mass, weight, crosslinking density, copolymer composition, and crystallinity, but not their mechanical properties during degradation. The aim of the proposed study was to address this gap by characterizing the mechanical properties of three biodegradable materials (PGA, PGCL, and PDO) as they underwent degradation. The study was conducted by testing the mechanical properties of these polymers at various stages of degradation through tensile testing. After conducting the mechanical tests, it was observed that PGCL underwent full degradation within 14 days, PGA within 30 days, and PDO was still degrading after 40 days but did not lose all its properties. These findings provide insight into the relationship between mechanical properties and degradation behavior of biodegradable polymers, which is important for the development of new materials and applications in the medical industry
Modeling the Ligaments of the Female Pelvic Floor System Through Iteration of Finite Element Analysis and a Transverse Isotropic Constitutive Model
No full textA significant number of women suffer from Pelvic Organ Prolapse, often accompanied by pain, discomfort, and embarrassment. By using a method known as Finite Element Analysis (FEA,) a 3D computer model can be used to help find answers to the problem. The usual method of obtaining anatomically accurate 3D models of human tissue, Magnetic Resonance Imaging (MRI,) separates tissues by water content, but the ligaments and their surrounding fat tissue appear the same on common MRI machines. Thus, another method must be found to model the ligaments. In this study, a FEA model of the pelvic region was constructed in FEBio, without any ligaments. Since ligaments impose strain on connected tissues, high strain in the model was localized. These locations had the direction of strain and a small surrounding volume along that direction also identified. Then the volume's properties were changed to match that of ligament tissue, employing the Transverse Isotropic constitutive model. From here the simulation was repeated many times, looking at strain on the tip of the previously modified volume, using a Python script to automate. The resulting process built new models of the uterosacral and cardinal ligaments that support the vaginal column
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
Collaborative Reinforcement Learning Control of Paired Vertical Axis Wind Turbines
No full textCapable of operating in omni-wind directions, vertical axis wind turbines are great candidates for ocean and urban applications, where wind directions vary frequently and dramatically. However, there are still many challenges when it comes to the design of control methods for turbines in urban settings, mainly due to the complex flow through the turbine, which makes it challenging to obtain an accurate dynamics model. This thesis proposes the use of a reinforcement learning algorithm to optimize a pitching trajectory for the VAWT to maximize efficiency. A twin collaborative VAWT setup is simulated under an urban-like environment for enhanced performance and faster learning. The application of a Parameter Exploring Policy Gradient (PGPE) is implemented to learn the optimal pitch control of a VAWT under varying wind conditions. The control system uses power measurement only to adjust the control policy. A comprehensive discussion of the parameter selection for policy approximation will be discussed. Three wind conditions are simulated to validate the effectiveness of the proposed reinforcement learning control method along with two policies tested. A comparison of the new wind turbine control to the traditional controls, operation, and energy efficiency will be also provided
Evolution of the Mechanical Properties of Degradable Biomaterials
No full textWith the increase of plastic waste pollution and lack of information about their degradation, it is necessary to study and identify appropriate biodegradable biomaterials to decrease the accumulation of non-degradable packaging waste. This work aims to determine the mechanical characteristics of 3D-printed compound biomaterials made from polylactic acid (PLA) and polycaprolactone (PCL) during a degradation process. Filaments were manufactured by physical blending of PLA and PCL materials in pellet form using a filament extruder with a mixing screw. The filaments manufactured included 100% PLA, 100% PCL, and ratios of 90/10, 80/20, 60/40, and 40/60 of PLA and PCL, respectively. A 3D printer was used to print dog-bone-shaped geometries out of the previously extruded compound materials; the dimensions of the dog-bones were optimized using finite element analysis software. The printed samples were submerged in a saline solution and kept at a constant temperature of 38°C for ten weeks. The mechanical characterization was done with a uniaxial tensile machine. The data collected was analyzed to obtain the elastic modulus, Yield, and Ultimate tensile stress (UTS). It was observed that as PCL is increased, the compound presents a ductile behavior with lower modulus, Yield, and UTS. At the end of the hydrolytic degradation process, the evolution of the mechanical properties of most of the materials shows a statistically significant difference
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