1,721,332 research outputs found
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Modelling, Design Optimisation and Experimental Evaluation of Propulsion Concepts for in-body Robotic Systems
No full textApplications of miniaturised robots in medicine have created significant opportunities for minimally invasive medicine. As a pioneer in such a field, wireless capsule endoscope (WCE) has brought significant advantages to the diagnosis of the gastrointestinal (GI) diseases, especially the symptoms in the small bowel to which a conventional endoscope is hard to reach. However, current commercial capsules depend on the natural peristalsis to move, which makes site-specific diagnosis and intervention less effective, limiting WCE’s prospect to a large degree. Therefore, substantial research is being dedicated to the active locomotion of WCEs, which is crucial for further therapeutic functionalities such as drug delivery and biopsy. This thesis reports on designing, optimising, fabricating, and testing locomotion mechanisms for a spiral-type robotic WCE for operation within the GI tract, especially in the small intestine, in a safe and reliable manner. The whole locomotion system functions by coupling a capsule robot containing a magnetic element via an external electromagnetic system. A three-axes circular Helmholtz coils has been employed to generate a rotating magnetic field to wirelessly provide actuation to the robotic capsule. By altering the frequency and amplitude of the electric current, this electromagnetic system is able to control the rotation speed and direction (in three dimensions) of the capsule. Biomechanical and biotribological properties of a real intestine were experimentally investigated in order to obtain a sound understanding of the working environment of the robotic capsule. Our findings demonstrate that the intestine’s biomechanical and biotribological properties are coupled, suggesting that the sliding friction is strongly related to the internal friction of the intestinal tissue. Sliding friction experiments were also conducted with bar-shaped solid samples to determine the sliding friction between the samples and the small intestine. Finite element analysis (FEA) has been used to optimise the geometry of a capsule robot assembled with spirals, like a screw assembled on its cylindrical surface. The computational fluid dynamics (CFD) has been employed to investigate the interaction between the capsule and a mucus film rather than the intestinal wall. The CFD predictions agree well with the corresponding experiments in which the spiral-type capsules (i.e. the capsule robot with spiral traction elements) were actuated by the external electromagnetic system. The FEA is extended to take the deformation and viscoelasticity of the intestine into account in order to realistically predict the propulsion performance of the capsule robot, evaluated experimentally. The close correspondence between experimental and numerical results from the FEA has encouraged us to use the FEA as a tool to evaluate the performance of different helical structures and consequently, undertake the design and optimization of the traction topology of a spiral-type capsule robot. Most literature in this field shows qualitative results on the mechanical and dynamic behaviors of a spiral-type robotic WCE moving inside a model GI tract, rather than testing in a real small intestine. Very little was reported on the theoretical and experimental evaluation of various spiral-type capsule robots. In this thesis, significant efforts have been made to provide substantial experimental data for quantitatively analysing the performance of different traction topologies of the robotic capsule, including the resistive torque, tractive force, locomotion ability and locomotion efficiency, through in vitro experiments with real porcine small intestines. It is revealed that the optimisation of such a robotic capsule is a compromise among propulsion velocity, stability, efficiency, and safety as well. From this point of view, an optimised traction topology was identified and recommended from the performance evaluation based on the experimental data. By these findings, a significant step has been taken towards a functional robotic capsule with a swallowable size, and the development of a powerful therapeutical WCE eventually
Estimation of State Space Models using Particle Filters – applications to Economics and Finance
No full textIn recent years, general state space models have been proven to be extremely useful in modelling wide range of economic and financial time series. Subsequently, particle filters, a computational simulation based method along with its related techniques had burst into our spectrum and fill our expectation of estimating general state space models. However, particle methods can be computationally intensive, as well as possibly requiring stringent restrictions on the parameters space to achieve timely convergence. In this thesis, I propose several improvements to particle methods on different aspects. A list of the improvements are: general computational time reduction in particle filters, modified particle smoothing algorithm, more accurate parameter and state variable estimation through the utilizations of Modified Entropy particle filter, and apply novel general state space model estimation method to real economic and financial time series
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
sj-pdf-1-lan-10.1177_00236772231188172 - Supplemental material for Investigation of circulating infectious agents in experimental Beagle dogs of a production colony and three research facilities in China from June 2021 to May 2022
No full textSupplemental material, sj-pdf-1-lan-10.1177_00236772231188172 for Investigation of circulating infectious agents in experimental Beagle dogs of a production colony and three research facilities in China from June 2021 to May 2022 by Yue Zhao, Panlong Wang, Xueting Qu, Kunpeng Yuan, Suzhen Zhu, Sen Wang, Qingdong Luan, Hao Zhou, Yue Yin, Zijing Zhao, Yongjuan Gao, Shuzhen Chen, Yanjing Lu, Jianlin Wang and Yanbo Yin in Laboratory Animals</p
- …
