Space-Time Transfinite Interpolation of Volumetric Material Properties

The paper presents a novel technique based on extension of a general mathematical method of transfinite interpolation to solve an actual problem in the context of a heterogeneous volume modelling area. It deals with time-dependent changes to the volumetric material properties (material density, colour and others) as a transformation of the volumetric material distributions in space-time accompanying geometric shape transformations such as metamorphosis. The main idea is to represent the geometry of both objects by scalar fields with distance properties, to establish in a higher-dimensional space a time gap during which the geometric transformation takes place, and to use these scalar fields to apply the new space-time transfinite interpolation to volumetric material attributes within this time gap. The proposed solution is analytical in its nature, does not require heavy numerical computations and can be used in real-time applications. Applications of this technique also include texturing and displacement mapping of time-variant surfaces, and parametric design of volumetric microstructures

Finite volume modelling of an icefield with subglacial lake

Momentum, mass and energy balance laws provide the tools for the study of the evolution of an icefield covering a subglacial lake. The ice is described as a non-Newtonian fluid with a power-law constitutive relationship with temperature- and stress-dependent viscosity (Glen?s law) [1]. The phase transition mechanisms at the air/ice and ice/water interfaces yield moving boundary formulations, and lake hydrodynamics requires equation reduction for treating the turbulence

Probabilistic partial volume modelling of biomedical tomographic image data

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Finite volume modelling of low speed structural impact problems

Two investigations are described in this thesis on the common theme of applying finite volume methods to simulate structural impact problems. The first investigation is the application of the Eulerian Finite Volume Method (EFVM) to simulate the low-speed impact of ductile materials. Simulation results are validated against experiment showing that it is possible to accurately predict crater deformation profiles over the low speed speed impact regime for different projectile and substrate materials. We demonstrate how the rate dependent Johnson-Cook plasticity model is crucial to ensure correspondence to experiment. The second investigation is concerned with the application of EFVM to simulate impact damage to thin polymeric coatings applied to the surface of metals. The aim of this work is to demonstrate how new simulation methods can help understand coating damage due stone impact. We simulate the debonding phenomenon of single layer coatings under impact by setting boundary conditions at the plate and paint interface. We show how EFVM can capture two limits of interface behaviour, sliding and separation 'slip' at one extreme and zero sliding 'welded' at the other. Results compare well to previously published experimental and simulation work, and our own finite element simulations in Abaqus. We also demonstrate how EFVM brings greater robustness and stability compared to FEM when modelling adhesive failure and higher energy impact penetration

The system dynamic method using for crediting volume modelling

This paper describes a system dynamic model of credit burden, and it provides an estimation of credit volume. The elaborated model calculates and estimates household budget balance and budget forming flows: income and expenditures, loan and interest payments, increase in budget balance depending on the amount of the granted loan and the costs associated with the purchase of the loan object. The elaborated model can also be applied in analysis of the national economy and in entrepreneurship. The paper presents a method for determining the amount of the loan for purchasing a flat for a household. It also provides modeling results of Latvia’s credit system and conclusions regarding its further development.system dynamic, model, credit burden

Predicting growing stock volume of Eucalyptus plantations using 3-D point clouds derived from UAV imagery and ALS data

Estimating forest inventory variables is important in monitoring forest resources and mitigating climate change. In this respect, forest managers require flexible, non-destructive methods for estimating volume and biomass. High-resolution and low-cost remote sensing data are increasingly available to measure three-dimensional (3D) canopy structure and to model forest structural attributes. The main objective of this study was to evaluate and compare the individual tree volume estimates derived from high-density point clouds obtained from airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) in Eucalyptus spp. plantations. Object-based image analysis (OBIA) techniques were applied for individual tree crown (ITC) delineation. The ITC algorithm applied correctly detected and delineated 199 trees from ALS-derived data, while 192 trees were correctly identified using DAP-based point clouds acquired fromUnmannedAerialVehicles(UAV), representing accuracy levels of respectively 62% and 60%. Addressing volume modelling, non-linear regression fit based on individual tree height and individual crown area derived from the ITC provided the following results: Model E ciency (Mef) = 0.43 and 0.46, Root Mean Square Error (RMSE) = 0.030 m3 and 0.026 m3, rRMSE = 20.31% and 19.97%, and an approximately unbiased results (0.025 m3 and 0.0004 m3) using DAP and ALS-based estimations, respectively. No significant di erence was found between the observed value (field data) and volume estimation from ALS and DAP (p-value from t-test statistic = 0.99 and 0.98, respectively). The proposed approaches could also be used to estimate basal area or biomass stocks in Eucalyptus spp. plantationsinfo:eu-repo/semantics/publishedVersio

Constructive Volumetric Modeling

Abstract—In this article we intend to present a method of obtaining high complexity sinthetic scenes by using simple volumes as the building blocks. The below described method can be used to obtain both homogenous and heterogenous volumes. This is done by combining volumes of different voxel densities. Index Terms—volumetric data, voxel, constructive solid geometry, volume modelling, constructive volume geometry. I

Distance based heterogeneous volume modelling.

Natural objects, such as bones and watermelons, often have a heterogeneous composition and complex internal structures. Material properties inside the object can change abruptly or gradually, and representing such changes digitally can be problematic. Attribute functions represent physical properties distribution in the volumetric object. Modelling complex attributes within a volume is a complex task. There are several approaches to modelling attributes, but distance functions have gained popularity for heterogeneous object modelling because, in addition to their usefulness, they lead to predictability and intuitiveness. In this thesis, we consider a unified framework for heterogeneous volume modelling, specifically using distance fields. In particular, we tackle various issues associated with them such as the interpolation of volumetric attributes through time for shape transformation and intuitive and predictable interpolation of attributes inside a shape. To achieve these results, we rely on smooth approximate distance fields and interior distances. This thesis deals with outstanding issues in heterogeneous object modelling, and more specifically in modelling functionally graded materials and structures using different types of distances and approximation thereof. We demonstrate the benefits of heterogeneous volume modelling using smooth approximate distance fields with various applications, such as adaptive microstructures, morphological shape generation, shape driven interpolation of material properties through time and shape conforming interpolation of properties. Distance based modelling of attributes allows us to have a better parametrization of the object volume and design gradient properties across an object. This becomes more important nowadays with the growing interest in rapid prototyping and digital fabrication of heterogeneous objects and can find practical applications in different industries

Volume modelling for emerging manufacturing technologies

The next generation manufacturing technologies will draw on new developments in geometric modelling. Based on a comprehensive analysis of the desiderata of next generation geometric modellers, we present a critical review of the major modelling paradigms, namely, CSG, B-Rep, non-manifold, and voxel models. We present arguments to support the view that voxel-based modellers have attributes that make it the representation scheme of choice in meeting the emerging requirements of geometric modelling

Anatomical studies of claw conformation in New Zealand dairy cattle : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science, Massey University, Palmerston North, New Zealand

The aim of the studies reported in this thesis was to extend our current knowledge on estimating and monitoring claw conformation under New Zealand conditions. Initially post mortem material was used to: (1) evaluate the utility of claw volume estimation with data from cull dairy cows; (2) validate the use of a portable ultrasound machine in the estimation of internal claw dimensions; and (3) apply morphometry to quantify vascular change in histological sections from the collected claw material. Analysis of the relationship between claw volume and hoof conformation revealed differences between the claws of dairy cattle used for this study and those of beef cattle which had been used previously. This necessitated the development of a different predictive model for dairy cattle which was subsequently used in the live animal studies. Validation of ultrasound estimates for sole and soft tissue thickness against calliper measurements in the sectioned claw, found that the portable machine used accurately estimated mean distance to distal phalanx (DP) and was thus suitable for categorising claws as having thin, marginal or adequate sole thickness. Morphometrical techniques were successfully applied to sections from frozen claw material; the ratio of vessel lumen area to overall vessel area was found to vary depending on site, claw and overall vessel size. No relationship was found between the ratio and claw horn haemorrhages, but the level of such lesions was low in the animals available for analysis. Subsequently, selected conformation traits were assessed on-farm in two consecutive cohorts of first lactation heifers. Some variables were identified as being useful to evaluate conformational change within a pasture-based system. These demonstrated dynamic change over the course of lactation. However, fluctuation in these variables at pasture means that any intervention study would need to have a greater impact on the claw than the variations produced by the background environment. Other variables showed stability over lactation and between years of study, and are therefore potentially suited to the investigation of claw size in relation to the development of lesions and lameness. In Year 1, ultrasound estimates of DP were recorded as a proxy for sole thickness. Values decreased significantly after calving to a nadir at approximately Day 110. The change in DP between Days 10 and 110 was associated with the initial value of DP on Day 10. The study concluded that thin soles increased in depth while thick soles wore to become thinner, indicating that heifers with thinner soles were able to accommodate to the changes occurring around and after calving and that the response of the claw to encountering tracks, collecting yards and milking parlours is not simply an increase in net wear. In Year 2, a novel method to capture changes in heel conformation was successfully trialled. Non-weight bearing heel length was found to alter rapidly after calving while other measures responded slowly in comparison and suggested extended monitoring was advisable. The on-farm studies established that, for most conformational variables, there is value in recording information from all four claws of the hind feet in a pasture based system