Representing and rendering sweep objects using volume models

When performing deep brain stimulation (DBS) of the subthalamic nucleus, practitioners should interpret the magnetic resonance images (MRI) correctly so they can place the DBS electrode accurately at the target without damaging the other structures. The aim of this study is to provide a real color volume model of a cadaver head that would help medical students and practitioners to better understand the sectional anatomy of DBS surgery. Sectioned images of a cadaver head were reconstructed into a real color volume model with a voxel size of 0.5 mm × 0.5 mm × 0.5 mm. According to preoperative MRIs and postoperative computed tomographys (CT) of 31 patients, a virtual DBS electrode was rendered on the volume model of a cadaver. The volume model was sectioned at the classical and oblique planes to produce real color images. In addition, segmented images of a cadaver head were formed into volume models. On the classical and oblique planes, the anatomical structures around the course of the DBS electrode were identified. The entry point, waypoint, target point, and nearby structures where the DBS electrode could be misplaced were also elucidated. The oblique planes could be understood concretely by comparing the volume model of the sectioned images with that of the segmented images. The real color and high resolution of the volume model enabled observations of minute structures even on the oblique planes. The volume models can be downloaded by users to be correlated with other patients’ data for grasping the anatomical orientation.

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Second-order discontinuous Galerkin flood model: Comparison with industry-standard finite volume models

Journal of Hydrology ◽

10.1016/j.jhydrol.2020.125924 ◽

2021 ◽

Vol 594 ◽

pp. 125924

Author(s):

Janice Lynn Ayog ◽

Georges Kesserwani ◽

James Shaw ◽

Mohammad Kazem Sharifian ◽

Domenico Bau

Keyword(s):

Discontinuous Galerkin ◽

Finite Volume ◽

Model Comparison ◽

Second Order ◽

Industry Standard ◽

Flood Model ◽

Volume Models

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Comparative analysis of hydrodynamics of treatment wetlands using finite volume models with empirical data

Desalination and Water Treatment ◽

10.1080/19443994.2014.957957 ◽

2014 ◽

Vol 55 (13) ◽

pp. 3587-3612 ◽

Cited By ~ 1

Author(s):

Rattandeep Singh ◽

Sandeep Gupta ◽

S. Raman ◽

Prodyut Chakraborty ◽

Puneet Sharma ◽

...

Keyword(s):

Comparative Analysis ◽

Finite Volume ◽

Empirical Data ◽

Treatment Wetlands ◽

Volume Models

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Optimization and parallelization of the discrete ordinate method for radiation transport simulation in OpenFOAM: Hierarchical combination of shared and distributed memory approaches

Open Research Europe ◽

10.12688/openreseurope.13017.1 ◽

2021 ◽

Vol 1 ◽

pp. 2

Author(s):

Jose Moreno-SanSegundo ◽

Cintia Casado ◽

David Concha ◽

Antonio S. Montemayor ◽

Javier Marugán

Keyword(s):

Distributed Memory ◽

Radiation Transport ◽

Computational Time ◽

Limiting Factor ◽

Discrete Ordinate Method ◽

Discrete Ordinate ◽

Radiation Sources ◽

Transport Problems ◽

Volume Models ◽

Spatial Cell

This paper describes the reduction in memory and computational time for the simulation of complex radiation transport problems with the discrete ordinate method (DOM) model in the open-source computational fluid dynamics platform OpenFOAM. Finite volume models require storage of vector variables in each spatial cell; DOM introduces two additional discretizations, in direction and wavelength, making memory a limiting factor. Using specific classes for radiation sources data, changing the store of fluxes and other minor changes allowed a reduction of 75% in memory requirements. Besides, a hierarchical parallelization was developed, where each node of the standard parallelization uses several computing threads, allowing higher speed and scalability of the problem. This architecture, combined with optimization of some parts of the code, allowed a global speedup of x15. This relevant reduction in time and memory of radiation transport opens a new horizon of applications previously unaffordable.

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Comprehensive yield model for plantation teak in Panama

Silva Fennica ◽

10.14214/sf.10309 ◽

2020 ◽

Vol 54 (5) ◽

Author(s):

Petteri Seppänen ◽

Antti Mäkinen

Keyword(s):

Input Parameter ◽

Large Diameter ◽

Measurement Data ◽

Growth And Yield ◽

Tree Level ◽

Stem Volume ◽

Yield Model ◽

Individual Tree ◽

Support Tool ◽

Volume Models

The purpose of this study was to prepare a comprehensive, computerized teak ( L.f) plantation yield model system that can be used to describe the forest dynamics, predict growth and yield and support forest planning and decision-making. Extensive individual tree and permanent sample plot data were used to develop tree-level volume models, taper curve models and stand-level yield models for teak plantations in Panama. Tree volume models were satisfactorily validated against independent measurement data and other published models. Tree height as input parameter improved the stem volume model marginally. Stand level yield models produced comparable harvest volumes with models published in the literature. Stand level volume product outputs were found like actual harvests with an exception that the models marginally underestimate the share of logs in very large diameter classes. The kind of comprehensive model developed in this study and implemented in an easy to use software package provides a very powerful decision support tool. Optimal forest management regimes can be found by simulating different planting densities, thinning regimes and final harvest ages. Forest practitioners can apply growth and yield models in the appropriate stand level inventory data and perform long term harvest scheduling at property level or even at an entire timberland portfolio level. Harvest schedules can be optimized using the applicable financial parameters (silviculture costs, harvesting costs, wood prices and discount rates) and constraints (market size and operational capacity).Tectona grandis

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Direct Measurement of Trunk Volume in Forest Trees: Focus on White Pine and Comparison to a Statistical Method

10.1101/2020.03.18.995985 ◽

2020 ◽

Author(s):

Robert T. Leverett ◽

David N. Ruskin ◽

Susan A. Masino

Keyword(s):

Carbon Storage ◽

Direct Measurement ◽

State Of The Art ◽

Forest Trees ◽

White Pine ◽

Individual Tree ◽

Average Value ◽

Direct Measurement Method ◽

Volume Models ◽

Taper Models

AbstractAccurate measurement of tree volume and associated carbon storage are necessary to determine ongoing sequestration as well as site productivity and changes in growth of individual tree species. Standard statistical methods vary their estimations of tree volume, and thus carbon storage and sequestration, particularly in larger, older trees in a forest setting. Here, we describe a detailed direct measurement method that combines traditional trunk taper models with state-of-the-art instrumentation and the best mathematical models for producing more accurate measurements of trunk volume. A stand-grown Eastern White Pine (Pinus strobus) is used as an example; the method is compared with a commonly used statistics-based Forest Service method. This latter method is shown to over- or underestimate volume if the trunk form factor deviates sufficiently from the average value for this species. Direct measurement modeling can be used to validate or choose among existing simple statistical volume models, especially for local applications. It can also assist in widespread recalibration of other standards and models used to estimate volume and carbon storage over time.

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