4,988 research outputs found

    Osteoporotic and Neoplastic Compression Fracture Classification on Longitudinal CT

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    Classification of vertebral compression fractures (VCF) having osteoporotic or neoplastic origin is fundamental to the planning of treatment. We developed a fracture classification system by acquiring quantitative morphologic and bone density determinants of fracture progression through the use of automated measurements from longitudinal studies. A total of 250 CT studies were acquired for the task, each having previously identified VCFs with osteoporosis or neoplasm. Thirty-six features or each identified VCF were computed and classified using a committee of support vector machines. Ten-fold cross validation on 695 identified fractured vertebrae showed classification accuracies of 0.812, 0.665, and 0.820 for the measured, longitudinal, and combined feature sets respectively.Comment: Contributed 4-Page Paper to be presented at the 2016 IEEE International Symposium on Biomedical Imaging (ISBI), April 13-16, 2016, Prague, Czech Republi

    Soul Connections

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    The work the author does touches his soul and the person he is caring for

    Towards a Geometric Approach to Strassen's Asymptotic Rank Conjecture

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    We make a first geometric study of three varieties in Cm⊗Cm⊗Cm\mathbb{C}^m \otimes \mathbb{C}^m \otimes \mathbb{C}^m (for each mm), including the Zariski closure of the set of tight tensors, the tensors with continuous regular symmetry. Our motivation is to develop a geometric framework for Strassen's Asymptotic Rank Conjecture that the asymptotic rank of any tight tensor is minimal. In particular, we determine the dimension of the set of tight tensors. We prove that this dimension equals the dimension of the set of oblique tensors, a less restrictive class introduced by Strassen.Comment: Final version. Revisions in Section 1 and Section

    The Analysis of the Major Determinants of Foreign Direct Investment: Case of Tanzania

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    This paper analyzes the determinants of foreign direct investment in Tanzania. In this paper the Ordinary least square (OLS) estimation technique has been used to analyze the relationship between foreign direct investment and its determinants with the help of the E-views 7.1 software. The result shows that the market size, infrastructure development and natural resources availability are the major determinants of foreign direct investment inflow to Tanzania. Therefore the main recommendations are: firstly Tanzania government need to make more effort in the expansion of the market that will attract more FDI ; secondly investing more on the infrastructure development hence encouraging more FDI to the country: Lastly the results found the natural resources availability to be significant but unexpectedly had negative sign contrary to our hypothesis which may imply that the inadequate of natural resources reduces FDI inflow to the country hence more exploration of natural resources is necessary to ensure its availability for example the new recent massive discovery of gas in the country might have a big impact on attracting FDI in the near future. Keywords: Foreign direct investment (FDI), Ordinary Least Square (OLS), unit root, Natural resources Availability (NRA)

    Deep convolutional networks for automated detection of posterior-element fractures on spine CT

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    Injuries of the spine, and its posterior elements in particular, are a common occurrence in trauma patients, with potentially devastating consequences. Computer-aided detection (CADe) could assist in the detection and classification of spine fractures. Furthermore, CAD could help assess the stability and chronicity of fractures, as well as facilitate research into optimization of treatment paradigms. In this work, we apply deep convolutional networks (ConvNets) for the automated detection of posterior element fractures of the spine. First, the vertebra bodies of the spine with its posterior elements are segmented in spine CT using multi-atlas label fusion. Then, edge maps of the posterior elements are computed. These edge maps serve as candidate regions for predicting a set of probabilities for fractures along the image edges using ConvNets in a 2.5D fashion (three orthogonal patches in axial, coronal and sagittal planes). We explore three different methods for training the ConvNet using 2.5D patches along the edge maps of 'positive', i.e. fractured posterior-elements and 'negative', i.e. non-fractured elements. An experienced radiologist retrospectively marked the location of 55 displaced posterior-element fractures in 18 trauma patients. We randomly split the data into training and testing cases. In testing, we achieve an area-under-the-curve of 0.857. This corresponds to 71% or 81% sensitivities at 5 or 10 false-positives per patient, respectively. Analysis of our set of trauma patients demonstrates the feasibility of detecting posterior-element fractures in spine CT images using computer vision techniques such as deep convolutional networks.Comment: To be presented at SPIE Medical Imaging, 2016, San Dieg

    Enhancement of thrust reverser cascade performance using aerodynamic and structural integration

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    This paper focuses on the design of a cascade within a cold stream thrust reverser during the early, conceptual stage of the product development process. A reliable procedure is developed for the exchange of geometric and load data between a two dimensional aerodynamic model and a three dimensional structural model. Aerodynamic and structural simulations are carried out using realistic operating conditions, for three different design configurations with a view to minimising weight for equivalent or improved aerodynamic and structural performance. For normal operational conditions the simulations show that total reverse thrust is unaffected when the performance of the deformed vanes is compared to the un-deformed case. This shows that for the conditions tested, the minimal deformation of the cascade vanes has no significant affect on aerodynamic efficiency and that there is scope for reducing the weight of the cascade. The pressure distribution through a two dimensional thrust reverser section is determined for two additional cascade vane configurations and it is shown that with a small decrease in total reverse thrust, it is possible to reduce weight and eliminate supersonic flow regimes through the nacelle section. By increasing vane sections in high pressure areas and decreasing sections in low pressure areas the structural performance of the cascade vanes in the weight reduced designs, is improved with significantly reduced levels of vane displacement and stress
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