The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Jihong Wang - One of the best experts on this subject based on the ideXlab platform.

  • tu f campus j 02 mooney rivlin biomechanical modeling of lung with Inhomogeneous Material property
    Medical Physics, 2015
    Co-Authors: Nasehi J Tehrani, X Guo, Jihong Wang
    Abstract:

    Purpose: The Mooney-Rivlin Material with hyperelastic strain energy has been proposed for realistic biomechanical modeling of lung. In this study, the lung is modeled as an Inhomogeneous Mooney-Rivlin Material with the incompressibility factors being optimized to improve the tumor center of mass (TCM) motion simulation accuracy during respiration. Method: ITK-SNAP was used to segment lungs of eight lung cancer patients from the 4D-CT images and tetrahedral volume meshes of the lungs in phase 50% were created by using adaptive mesh generation toolkit. The interphase deformation vector fields (DVFs) are calculated by demons deformable registration algorithm and the barycentric coordinate system of tetrahedral elements is obtained from the resulted DVFs. Mooney-Rivlin hyperelastic Material is used to model the lung volume. Each element is considered unique where the incompressibility factor (k-factor) for each element is assumed to be proportional to the magnitude of normalized DVF. The incompressibility factor for each element was optimized by minimizing the tumor center of mass motion simulation error. Results: If lung is considered as a homogenous Material in Mooney-Rivlin modeling, the average TCM motion simulation error is 2.26 mm. By considering Inhomogeneous properties of lung in the proposed strategy, the average TCM motion simulation error is reduced to 2.04 mm. Conclusions: We proposed a method for assigning the Inhomogeneous biomechanical Material in the Mooney-Rivlin model of lung based on the lung regional deformation vector fields. Inhomogeneous Material property of lung improves the simulation accuracy.

  • Mooney-Rivlin biomechanical modeling of lung with Inhomogeneous Material
    2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
    Co-Authors: Nasehi J Tehrani, Jihong Wang
    Abstract:

    In this study, the Mooney-Rivlin Material with hyperelastic strain energy was proposed for biomechanical modeling of the lung. We modeled the lung as an Inhomogeneous Mooney-Rivlin Material with uncoupled deviatoric and volumetric behavior. The proposed method was evaluated on the lungs of eight lung cancer patients. For each patient, the lung was segmented from the 4D-CT images and tetrahedral volume mesh of the lung in phase 50% was created by using the adaptive mesh generation toolkit. The demons deformable registration algorithm was used to extract the displacement vector fields (DVFs). The Jacobian of the deformation gradient was calculated from DVFs, and the lung strain energy function was optimized to improve the tumor center of mass (TCM) motion simulation accuracy between respiratory phase 50% and 0%. The average TCM motion simulation error for the proposed strategy is 1.95 mm for eight patients. We observed 13% improvement in the TCM position prediction compared with the homogeneous Mooney-Rivlin modeling.

Nasehi J Tehrani - One of the best experts on this subject based on the ideXlab platform.

  • tu f campus j 02 mooney rivlin biomechanical modeling of lung with Inhomogeneous Material property
    Medical Physics, 2015
    Co-Authors: Nasehi J Tehrani, X Guo, Jihong Wang
    Abstract:

    Purpose: The Mooney-Rivlin Material with hyperelastic strain energy has been proposed for realistic biomechanical modeling of lung. In this study, the lung is modeled as an Inhomogeneous Mooney-Rivlin Material with the incompressibility factors being optimized to improve the tumor center of mass (TCM) motion simulation accuracy during respiration. Method: ITK-SNAP was used to segment lungs of eight lung cancer patients from the 4D-CT images and tetrahedral volume meshes of the lungs in phase 50% were created by using adaptive mesh generation toolkit. The interphase deformation vector fields (DVFs) are calculated by demons deformable registration algorithm and the barycentric coordinate system of tetrahedral elements is obtained from the resulted DVFs. Mooney-Rivlin hyperelastic Material is used to model the lung volume. Each element is considered unique where the incompressibility factor (k-factor) for each element is assumed to be proportional to the magnitude of normalized DVF. The incompressibility factor for each element was optimized by minimizing the tumor center of mass motion simulation error. Results: If lung is considered as a homogenous Material in Mooney-Rivlin modeling, the average TCM motion simulation error is 2.26 mm. By considering Inhomogeneous properties of lung in the proposed strategy, the average TCM motion simulation error is reduced to 2.04 mm. Conclusions: We proposed a method for assigning the Inhomogeneous biomechanical Material in the Mooney-Rivlin model of lung based on the lung regional deformation vector fields. Inhomogeneous Material property of lung improves the simulation accuracy.

  • Mooney-Rivlin biomechanical modeling of lung with Inhomogeneous Material
    2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015
    Co-Authors: Nasehi J Tehrani, Jihong Wang
    Abstract:

    In this study, the Mooney-Rivlin Material with hyperelastic strain energy was proposed for biomechanical modeling of the lung. We modeled the lung as an Inhomogeneous Mooney-Rivlin Material with uncoupled deviatoric and volumetric behavior. The proposed method was evaluated on the lungs of eight lung cancer patients. For each patient, the lung was segmented from the 4D-CT images and tetrahedral volume mesh of the lung in phase 50% was created by using the adaptive mesh generation toolkit. The demons deformable registration algorithm was used to extract the displacement vector fields (DVFs). The Jacobian of the deformation gradient was calculated from DVFs, and the lung strain energy function was optimized to improve the tumor center of mass (TCM) motion simulation accuracy between respiratory phase 50% and 0%. The average TCM motion simulation error for the proposed strategy is 1.95 mm for eight patients. We observed 13% improvement in the TCM position prediction compared with the homogeneous Mooney-Rivlin modeling.

Heinz Ulbrich - One of the best experts on this subject based on the ideXlab platform.

  • force modeling of Inhomogeneous Material using unsupervised learning and model identification
    Robotics and Biomimetics, 2009
    Co-Authors: Chen Zhao, Heinz Ulbrich
    Abstract:

    In this paper a force modeling method for Inhomogeneous Materials is introduced. This modeling method is based on samples during haptic operations, for instance presses. Using biomimetic unsupervised learning, the model is primarily identified, including the distribution and Material parameters of the Inhomogeneous regions, and in this learning the parameter initial estimation, the principal component analysis, the cluster analysis and the quadratic discriminant analysis are applied. Then the Material parameters and boundaries of the different regions are accurately optimized using the Gauss-Newton algorithm. Further more the modeling method is tested and verified by a set of simulations. In addition, the suggestions and prospect of the modeling method are also given.

  • ROBIO - Force modeling of Inhomogeneous Material using unsupervised learning and model identification
    2008 IEEE International Conference on Robotics and Biomimetics, 2009
    Co-Authors: Chen Zhao, Heinz Ulbrich
    Abstract:

    In this paper a force modeling method for Inhomogeneous Materials is introduced. This modeling method is based on samples during haptic operations, for instance presses. Using biomimetic unsupervised learning, the model is primarily identified, including the distribution and Material parameters of the Inhomogeneous regions, and in this learning the parameter initial estimation, the principal component analysis, the cluster analysis and the quadratic discriminant analysis are applied. Then the Material parameters and boundaries of the different regions are accurately optimized using the Gauss-Newton algorithm. Further more the modeling method is tested and verified by a set of simulations. In addition, the suggestions and prospect of the modeling method are also given.

Yangjie Liu - One of the best experts on this subject based on the ideXlab platform.

  • direct manipulation of wave amplitude and phase through inverse design of isotropic media
    New Journal of Physics, 2017
    Co-Authors: Yangjie Liu, Benjamin Vial, S A R Horsley, T G Philbin, Yang Hao
    Abstract:

    In this article we propose a new design methodology allowing us to control both amplitude and phase of electromagnetic waves from a cylindrical incident wave. This results in isotropic Materials and does not resort to transformation optics or its quasi-conformal approximations. Our method leads to two-dimensional isotropic, Inhomogeneous Material profiles of permittivity and permeability, to which a general class of scattering-free wave solutions arise. Our design is based on the separation of the complex wave solution into amplitude and phase. We give two types of examples to validate our methodology.

X Guo - One of the best experts on this subject based on the ideXlab platform.

  • tu f campus j 02 mooney rivlin biomechanical modeling of lung with Inhomogeneous Material property
    Medical Physics, 2015
    Co-Authors: Nasehi J Tehrani, X Guo, Jihong Wang
    Abstract:

    Purpose: The Mooney-Rivlin Material with hyperelastic strain energy has been proposed for realistic biomechanical modeling of lung. In this study, the lung is modeled as an Inhomogeneous Mooney-Rivlin Material with the incompressibility factors being optimized to improve the tumor center of mass (TCM) motion simulation accuracy during respiration. Method: ITK-SNAP was used to segment lungs of eight lung cancer patients from the 4D-CT images and tetrahedral volume meshes of the lungs in phase 50% were created by using adaptive mesh generation toolkit. The interphase deformation vector fields (DVFs) are calculated by demons deformable registration algorithm and the barycentric coordinate system of tetrahedral elements is obtained from the resulted DVFs. Mooney-Rivlin hyperelastic Material is used to model the lung volume. Each element is considered unique where the incompressibility factor (k-factor) for each element is assumed to be proportional to the magnitude of normalized DVF. The incompressibility factor for each element was optimized by minimizing the tumor center of mass motion simulation error. Results: If lung is considered as a homogenous Material in Mooney-Rivlin modeling, the average TCM motion simulation error is 2.26 mm. By considering Inhomogeneous properties of lung in the proposed strategy, the average TCM motion simulation error is reduced to 2.04 mm. Conclusions: We proposed a method for assigning the Inhomogeneous biomechanical Material in the Mooney-Rivlin model of lung based on the lung regional deformation vector fields. Inhomogeneous Material property of lung improves the simulation accuracy.