1,720,990 research outputs found
An investigation into Abdominal Aortic Aneurysm (AAA) rupture prediction
No full textCardiovascular Disease (CVD) is one of the leading causes of death and disability in the world. The mortality rate between 1993 -1997 in New Zealand was about 46% and 32% worldwide. CVDs such as Abdominal Aortic Aneurysm (AAA) is life threatening and poses a very high risk for aneurysm patients with particular aneurysm diameter.
AAA rupture is a patient-specific problem with evolving structures and on-going growth. Current ultrasound methods are used to probe for and diagnose instantaneous AAA by analysing arterial tissue deformation. However, tracking the progression of potential aneurysms, and predicting their risk of rupturing based on the diameter of the aneurysm is still an insufficient method. AAA image segmentation and analysis using the Patient-Specific Aneurysm Rupture Predictor (P-SARP) protocol is proposed to identify dependent elements that lead to a three-dimensional (3-D) aneurysm reconstructive model. Models of the patient-specific aneurysm images were designed along with biomechanical characterization and specific material properties to be incorporated. Fluid Structure Interaction (FSI) is used to mathematically establish the oscillations of patient-specific cyclic pressure loading in order to visualize the impact of potential pressure distributions on the deformed arterial wall over time. The correlation between the geometric elements and the models’ potential for rupture are extensively investigated to produce a possible AAA rupture mechanism.
This research presents a new Computational Fluid Dynamics (CFD) of Patient-Specific Aneurysm Model (PSAM) which is based on the energy strain function combined with the dilated vessel wall stress-strain relationship to predict aneurysm rupture. This thesis focuses on investigating how computer simulation can be incorporated to predict AAA rupture. The personalized model is developed based on instantaneous arterial deformations obtained from ultrasound images using a 6-9 MHz doppler transducer. The PSAM relies on available vii
mechanical properties and parameters obtained from the personalised model. Using the strain energy function based on historical stress-strain relationship to extrapolate cyclic loading on the PSAM along with patient-specific pressure, multi variant factors are proposed and considered to predict the actual location of the weakening points to reach rupture. The material properties of the wall are calculated using biaxial tensile tests to observe the time dependency of the material response and formation of the aneurysm wall rupture.
The outcomes indicate that the proposed technique of the PSAM model has the ability correlate the wall deformation and tissue failure mode with predicting rupture. Thus, this method can positively be integrated with already established ultrasound techniques for improvements in the accuracy of future diagnoses of potential AAA ruptures
An Investigation into Abdominal Aortic Aneurysm (AAA) Rupture Prediction
No full textCardiovascular Disease (CVD) is one of the leading causes of death and disability in the world. The mortality rate between 1993 -1997 in New Zealand was about 46% and 32% worldwide. CVDs such as Abdominal Aortic Aneurysm (AAA) is life threatening and poses a very high risk for aneurysm patients with particular aneurysm diameter.
AAA rupture is a patient-specific problem with evolving structures and on-going growth. Current ultrasound methods are used to probe for and diagnose instantaneous AAA by analysing arterial tissue deformation. However, tracking the progression of potential aneurysms, and predicting their risk of rupturing based on the diameter of the aneurysm is still an insufficient method. AAA image segmentation and analysis using the Patient-Specific Aneurysm Rupture Predictor (P-SARP) protocol is proposed to identify dependent elements that lead to a three-dimensional (3-D) aneurysm reconstructive model. Models of the patient-specific aneurysm images were designed along with biomechanical characterization and specific material properties to be incorporated. Fluid Structure Interaction (FSI) is used to mathematically establish the oscillations of patient-specific cyclic pressure loading in order to visualize the impact of potential pressure distributions on the deformed arterial wall over time. The correlation between the geometric elements and the models’ potential for rupture are extensively investigated to produce a possible AAA rupture mechanism.
This research presents a new Computational Fluid Dynamics (CFD) of Patient-Specific Aneurysm Model (PSAM) which is based on the energy strain function combined with the dilated vessel wall stress-strain relationship to predict aneurysm rupture. This thesis focuses on investigating how computer simulation can be incorporated to predict AAA rupture. The personalized model is developed based on instantaneous arterial deformations obtained from ultrasound images using a 6-9 MHz doppler transducer. The PSAM relies on available vii
mechanical properties and parameters obtained from the personalised model. Using the strain energy function based on historical stress-strain relationship to extrapolate cyclic loading on the PSAM along with patient-specific pressure, multi variant factors are proposed and considered to predict the actual location of the weakening points to reach rupture. The material properties of the wall are calculated using biaxial tensile tests to observe the time dependency of the material response and formation of the aneurysm wall rupture.
The outcomes indicate that the proposed technique of the PSAM model has the ability correlate the wall deformation and tissue failure mode with predicting rupture. Thus, this method can positively be integrated with already established ultrasound techniques for improvements in the accuracy of future diagnoses of potential AAA ruptures
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
Overall equipment utilisation (OEU) monitoring and remote quality check in legacy machine with raspberry pi
No full textAbstract
Overall Equipment Utilisation (OEU) plays an important role as a benchmark for manufacturing companies to determine each machine's efficiency. Currently, there is no proper OEU measurement system in legacy machines and only relies on human observation. This project aims to develop a measurement of OEU system by using Optical Character Recognition (OCR). An efficient Optical Character Recognition (OCR) algorithm is needed to have a high percentage of recognition rate. The outcome of this project will be a Graphical User Interface (GUI) that display real-time OEU monitoring and remote quality check for legacy machines. Pytesseract-OCR Version 4 classifier using the Recurrent Neural Network (RNN) method has been proposed in this paper. Furthermore, an error detection feature is designed from OCR output
Modelling and simulation analysis of rolling motion of spherical robot
No full textThis paper presents the findings of modelling, control and analysis of the spherical
rolling robot based on pendulum driven within the simulation environment. The spherical robot
is modelled using Lagrange function based on the equation of rolling motion. PD-type Fuzzy
logic controller (FLC) was designed to control the position of the spherical robot where 25 rules
were constructed to control the rolling motion of spherical robot. It was then integrated with the
model developed in Simulink-Matlab environment. The output scaling factor (output gain) of
the FLC was heuristically tuned to improve the system performance. The simulation results show
that the FLC managed to eliminate the overshoot response and demonstrated better performance
with 29.67% increasing in settling time to reach 0.01% of steady state error
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
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
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