6 research outputs found

    Multiple 2D self organising map network for surface reconstruction of 3D unstructured data

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    Surface reconstruction is a challenging task in reverse engineering because it must represent the surface which is similar to the original object based on the data obtained. The data obtained are mostly in unstructured type whereby there is not enough information and incorrect surface will be obtained. Therefore, the data should be reorganised by finding the correct topology with minimum surface error. Previous studies showed that Self Organising Map (SOM) model, the conventional surface approximation approach with Non Uniform Rational B-Splines (NURBS) surfaces, and optimisation methods such as Genetic Algorithm (GA), Differential Evolution (DE) and Particle Swarm Optimisation (PSO) methods are widely implemented in solving the surface reconstruction. However, the model, approach and optimisation methods are still suffer from the unstructured data and accuracy problems. Therefore, the aims of this research are to propose Cube SOM (CSOM) model with multiple 2D SOM network in organising the unstructured surface data, and to propose optimised surface approximation approach in generating the NURBS surfaces. GA, DE and PSO methods are implemented to minimise the surface error by adjusting the NURBS control points. In order to test and validate the proposed model and approach, four primitive objects data and one medical image data are used. As to evaluate the performance of the proposed model and approach, three performance measurements have been used: Average Quantisation Error (AQE) and Number Of Vertices (NOV) for the CSOM model while surface error for the proposed optimised surface approximation approach. The accuracy of AQE for CSOM model has been improved to 64% and 66% when compared to 2D and 3D SOM respectively. The NOV for CSOM model has been reduced from 8000 to 2168 as compared to 3D SOM. The accuracy of surface error for the optimised surface approximation approach has been improved to 7% compared to the conventional approach. The proposed CSOM model and optimised surface approximation approach have successfully reconstructed surface of all five data with better performance based on three performance measurements used in the evaluation

    University entry selection framework using rule-based and back-propagation

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    Processing thousands of applications can be a challenging task, especially when the applicant does not consider the university requirements and their qualification. The selection officer will have to check the program requirements and calculate the merit score of the applicants. This process is based on rules determined by the Ministry of Education and the institution will have to select the qualified applicants among thousands of applications. In recent years, several student selection methods have been proposed using the fuzzy multiple decision making and decision trees. These approaches have produced high accuracy and good detection rates on closed domain university data. However, current selection procedure requires the admission officers to manually evaluate the applications and match the applicants’ qualifications with the program they applied. Because the selection process is tedious and very prone to mistakes, a comprehensive approach to detect and identify qualified applicants for university enrollment is highly desired. In this work, a student selection framework using rule-based and backpropagation neural network is presented. Two processes are involved in this work; the first phase known as pre-processing uses rule-based for checking the university requirements, merit calculation and data conversion to serve as input for the next phase. The second phase uses back-propagation neural network model to evaluate the qualified candidates for admission to particular programs. This means only selected data of the qualified applicants from the first phase will be sent to the next phase for further processing. The dataset consists of 3,790 datasets from Universiti Pendidikan Sultan Idris. The experiments have shown that the proposed method of ruled-based and back-propagation neural network produced better performance, where the framework has successfully been implemented and validated with the average performance of more than 95% accuracy for student selection across all sets of the test data

    Conceptual framework of a novel hybrid methodology between computational fluid dynamics and data mining techniques for medical dataset application

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    This thesis proposes a novel hybrid methodology that couples computational fluid dynamic (CFD) and data mining (DM) techniques that is applied to a multi-dimensional medical dataset in order to study potential disease development statistically. This approach allows an alternate solution for the present tedious and rigorous CFD methodology being currently adopted to study the influence of geometric parameters on hemodynamics in the human abdominal aortic aneurysm. This approach is seen as a “marriage” between medicine and computer domains

    Frameworks in medical image analysis with deep neural networks

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    In recent years, deep neural network based medical image analysis has become quite powerful and achieved similar results performance-wise as experts. Consequently, the integration of these tools into the clinical routine as clinical decision support systems is highly desired. The benefits of automatic image analysis for clinicians are massive, ranging from improved diagnostic as well as treatment quality to increased time-efficiency through automated structured reporting. However, implementations in the literature revealed a significant lack of standardization in pipeline building resulting in low reproducibility, high complexity through extensive knowledge requirements for building state-of-the-art pipelines, and difficulties for application in clinical research. The main objective of this work is the standardization of pipeline building in deep neural network based medical image segmentation and classification. This is why the Python frameworks MIScnn for medical image segmentation and AUCMEDI for medical image classification are proposed which simplify the implementation process through intuitive building blocks eliminating the need for time-consuming and error-prone implementation of common components from scratch. The proposed frameworks include state-of-the-art methodology, follow outstanding open-source principles like extensive documentation as well as stability, offer rapid as well as simple application capabilities for deep learning experts as well as clinical researchers, and provide cutting-edge high-performance competitive with the strongest implementations in the literature. As secondary objectives, this work presents more than a dozen in-house studies as well as discusses various external studies utilizing the proposed frameworks in order to prove the capabilities of standardized medical image analysis. The presented studies demonstrate excellent predictive capabilities in applications ranging from COVID-19 detection in computed tomography scans to the integration into a clinical study workflow for Gleason grading of prostate cancer microscopy sections and advance the state-of-the-art in medical image analysis by simplifying experimentation setups for research. Furthermore, studies for increasing reproducibility in performance assessment of medical image segmentation are presented including an open-source metric library for standardized evaluation and a community guideline on proper metric usage. The proposed contributions in this work improve the knowledge representation of the field, enable rapid as well as high-performing applications, facilitate further research, and strengthen the reproducibility of future studies

    Automatisierte Segmentierung und Volumetrie bispektraler Magnetresonanz-Bilddaten des Gehirns

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