Large 3D Models Research Articles

Saliency-Guided Lighting

The comprehensibility of large and complex 3D models can be greatly enhanced by guiding viewer's attention to important regions. Lighting is crucial to our perception of shape. Careful use of lighting has been widely used in art, scientific illustration, and computer graphics to guide visual attention. In this paper, we explore how the saliency of 3D objects can be used to guide lighting to emphasize important regions and suppress less important ones.

Reservoir Imaging Using Induced Microseismicity

Activities within a hydrocarbon reservoir, such as producing oil or injecting fluid, change in-situ stresses which consequently cause micro-earthquakes. The induced microseismic events are small earthquakes producing high frequency waves which can be used to give a better understanding of the hydrocarbon reservoir. However, induced microseismic events are too small in magnitude to be detected on the surface due to seismic wave attenuation through the overburden. Therefore, in order to make use of such induced microseismic waves for monitoring, characterizing and/or imaging of the hydrocarbon reservoir, one should use buried sensors within monitoring wells. The microseismic events generated within a hydrocarbon reservoir as a result of the production activities are recorded. Then, the recorded first arrival times are used in inversion process to arrive at a detailed velocity model in the vicinity of the reservoir. The inversion process is based on a fast 3D finite-difference code using the eikonal equation to model the travel times of first arriving seismic events and; therefore, making the inversion of large 3D model practical. The methodology could lead to enhanced understanding and hence efficient management of the hydrocarbon reservoir. This in turn would enhance the understanding of fluid movements resulting in improved petroleum recovery from the reservoir.

Scalable, Adaptive Streaming for Nonlinear Media

Streaming linear media objects has become ubiquitous on today's Internet. Interactive, nonlinear media objects, such as large 3D models and visualization databases, have proven difficult to stream. The channel set adaptation (CSA) framework lets clients request custom data flows for interactive applications using standard broadcast or multicast join and leave operations. CSA scales to support large user groups while providing interactive data access to clients.

3D ray tracing using a modified shortest-path method

We present an accurate 3D ray-tracing algorithm based on a modified (more flexible and economical) shortest-path method (SPM). Unlike the regular SPM in the 3D case, which uses only primary nodes at the corners of each cell and whose accuracy depends on actual cell size, the new method can work with much larger cell sizes by introducing secondary nodes along all bounding surfaces of the cell. This increases the ray angular coverage and permits detailed specification of the velocity field. The modified SPM simultaneously calculates first-arrival times and gradually locates the related raypaths on all grid nodes as the wave field evolves. Its advantages over the regular SPM are its ability to handle high-contrast velocity models more easily, lower memory requirements and less CPU time, and the capability to calculate a relatively large 3D model without losing accuracy. The maximum relative error bound in the computed traveltimes of the modified SPM is established for a uniform velocity field, which may be considered an upper error bound for the whole model in real problems. The modified method in this study is compared with the regular SPM theoretically and on two specific velocity models. The Marmousi model is used to further test the performance of the new approach for both accuracy and flexibility in a complex velocity field. The study shows that the modified SPM is preferable to regular SPM for real 3D problems.

Structural characterization of heterodimeric laccases from Pleurotus ostreatus

The subfamily of POXA3 laccase isoenzymes produced by the fungus Pleurotus ostreatus has been characterized as an example of the complexity and heterogeneity of fungal isoenzyme patterns. Two isoenzymes, POXA3a and POXA3b, were previously purified, exhibiting an unusual heterodimeric structure composed of a large (67 kDa) and a small (18 or 16 kDa) subunit. A unique gene encodes the large subunit of both POXA3a and POXA3b, but alternative splicing produces two variants--differing for an insertion of four amino acids--for each isoenzyme. Two genes encoding POXA3a and POXA3b small subunits have been identified, and the corresponding amino acid sequences show only two amino acid substitutions. The 18- and 16-kDa subunits of both POXA3a and POXA3b differ for N-glycosylation at Asn150 of the 16-kDa subunit. The POXA3 large subunit 3D model allows us to highlight peculiarities of this molecule with respect to the laccases whose 3D structures are known.

Research on 3D Geomechanics Model Test for a Large-Scale Offspur Tunnel Project

Geomechanics model test has some distinctive advantages in simulating changing laws of stress and strain of rockmass as well as failure mechanism of surrounding rockmass of tunnel. In order to systematically study mechanics deformation properties of a large-scale offspur tunnel under excavation state, we design and manufacture a large scale 3D model test rack installation with hydraulic equipment. The test rack is 3.7 meters long, 2.2 meters wide and 4 meters high, which is the largest 3D geomechanics model test rack in present Chinese communication trades. The new-type similar material of model is a kind of cementitious composite which is mixed with iron ore powder, blanc fix, quartz sand, rosin, industrial alcohol and gypsum powder. 3D geomechanics model test for a large-scale offspur tunnel is carried out by utilizing the test installation and the similar material. The original design and construction of the offspur tunnel has been effectively optimized by results from model test.

MR thermometry characterization of a hyperthermia ultrasound array designed using the k-space computational method

BackgroundUltrasound induced hyperthermia is a useful adjuvant to radiation therapy in the treatment of prostate cancer. A uniform thermal dose (43°C for 30 minutes) is required within the targeted cancerous volume for effective therapy. This requires specific ultrasound phased array design and appropriate thermometry method. Inhomogeneous, acoustical, three-dimensional (3D) prostate models and economical computational methods provide necessary tools to predict the appropriate shape of hyperthermia phased arrays for better focusing. This research utilizes the k-space computational method and a 3D human prostate model to design an intracavitary ultrasound probe for hyperthermia treatment of prostate cancer. Evaluation of the probe includes ex vivo and in vivo controlled hyperthermia experiments using the noninvasive magnetic resonance imaging (MRI) thermometry.MethodsA 3D acoustical prostate model was created using photographic data from the Visible Human Project®. The k-space computational method was used on this coarse grid and inhomogeneous tissue model to simulate the steady state pressure wavefield of the designed phased array using the linear acoustic wave equation. To ensure the uniformity and spread of the pressure in the length of the array, and the focusing capability in the width of the array, the equally-sized elements of the 4 × 20 elements phased array were 1 × 14 mm. A probe was constructed according to the design in simulation using lead zerconate titanate (PZT-8) ceramic and a Delrin® plastic housing. Noninvasive MRI thermometry and a switching feedback controller were used to accomplish ex vivo and in vivo hyperthermia evaluations of the probe.ResultsBoth exposimetry and k-space simulation results demonstrated acceptable agreement within 9%. With a desired temperature plateau of 43.0°C, ex vivo and in vivo controlled hyperthermia experiments showed that the MRI temperature at the steady state was 42.9 ± 0.38°C and 43.1 ± 0.80°C, respectively, for 20 minutes of heating.ConclusionUnlike conventional computational methods, the k-space method provides a powerful tool to predict pressure wavefield in large scale, 3D, inhomogeneous and coarse grid tissue models. Noninvasive MRI thermometry supports the efficacy of this probe and the feedback controller in an in vivo hyperthermia treatment of canine prostate.

A finite shell element for heart mitral valve leaflet mechanics, with large deformations and 3D constitutive material model

This paper presents a shell finite element formulation appropriate for simulating the heart valve leaflet mechanics, including three-dimensional (3D) stress and strain effects. A 4-node mixed-interpolation shell is formulated in convected coordinates. This shell model is made capable of handling arbitrary 3D material models by use of an algorithm that satisfies the shell stress assumption at every element integration point. A method for tracking the fiber direction is incorporated. The resulting shell element operates under the same conditions as a standard 4-node shell element with 5 degrees of freedom per node, but extends the modeling capabilities to handle large-deformation and anisotropic behavior.

Field programmable gate array based parallel matrix multiplier for 3D affine transformations

3D graphics performance is increasing faster than any other computing application. Almost all PC systems now include 3D graphics accelerators for games, computer aided design or visualisation applications. This article investigates the suitability of field programmable gate array devices as an accelerator for implementing 3D affine transformations. Proposed solution based on processing large matrix multiplication have been implemented, for large 3D models, on the RC1000 Celoxica board based development platform using Handel-C. Outstanding results have been obtained for the acceleration of 3D transformations using fixed and floating-point arithmetic.

Interfacial delamination and fatigue life estimation of 3D solder bumps in flip-chip packages

Detailed three-dimensional finite element analysis was carried out for area-array solder-bumped flip-chip packages. The analysis enabled determinations of accurate three-dimensional effects on stress distributions as well as local fracture behaviors under thermal load. The 3D analysis also estimated thermal fatigue life of solder bumps. Since dimensions of various components span more than three orders of magnitude, the multi-scale finite element models were utilized to elucidate detailed deformation state near solder bumps. The global–local approach identified of critical solder bumps due to the overall deformation and investigated of interfacial delamination at microstructural level. The local model contained a single solder bump and sub-micron UBM layers. The two-step modeling approach enabled accurate fracture analysis otherwise difficult in large 3D models. Our analysis found the crack driving force and preferred delamination direction based on the 3D J-integral calculations. Shear deformations within and surrounding solder bump connectors were also investigated. The results revealed higher deformation in the 3D model than those predicted from 2D models. Additionally, the strain components were different. This has an important implication on the plastic flow characteristics during cyclic loading. Our model estimated about 25% greater steady-state shear strains in the 3D model than those in the 2D models. This result suggests a much shorter fatigue life than that based on the 2D analysis.

Modelling and processing of 3D seismic data collected over the overlapping spreading centre on the East Pacific Rise at 9° 03′ N

Abstract Oceanic ridges are important as the locus for the generation of new crust associated with the movement of plates on the Earth’s surface. The geometry of the axial magma chamber (AMC) under these ridges is poorly constrained. This is especially true for the AMC under an overlapping spreading centre (OSC) where the ridge undergoes a small lateral offset, typically less than 8 km. One such OSC exists on the East Pacific Rise at 9° 03′ N. Both 2D and more recently 3D seismic reflection surveys have been conducted over the area in an attempt to establish the relationship of the AMC with the two overlapping limbs of the axial rise. A major problem for imaging the AMC is caused by the seafloor, which has a large velocity contrast and has rapid changes in topography. This presents a major challenge for the processing of data. This paper aims to show that the understanding the effects of acquisition and processing can be facilitated by accurate 3D modelling of the seismic wavefield. In this paper we use a modelling method based on complex-screens, which is both robust and fast for large 3D models with deep water and diffractive interfaces. We compare synthetics with real data and explore the sensitivity of processing 3D data from shot gather to final 3D depth-migrated image. We show that the combination of severe seabed topography and 3D velocity variation within the oceanic crust causes distortion and complex focusing of the reflected energy. Also, for data with only sparse reflectivity it is not possible to construct an adequate velocity model for depth imaging from the reflection data alone. This problem may be overcome if there is an alternative method to determine velocity, e.g. refraction data, but care must be exercised during interpretation given the different resolutions of the two datasets. Lessons from the modelling exercise can be used to aid the interpretation of the real data and examples are shown for comparison; however, the geological implications of the results are outside the scope of this paper.

The development of the floor response spectra using large 3D model

This paper presents the development of the synthetic ground motion, the set up of a large 3D model for the reactor building and the development of the in-structure response spectra without any reduction of the model size by either condensation methods or component mode synthesis methods.

Nested gridding and streamline-based simulation for fast reservoir performance prediction

Detailed reservoir models routinely contain 106–108 grid blocks. These models often cannot be used directly in a reservoir simulation because of the time and memory required for solving the pressure grid on the fine grid. We propose a nested gridding technique that efficiently obtains an approximate solution for the pressure field. The domain is divided into a series of coarse blocks, each containing several fine cells. Effective mobilities are computed for each coarse grid block and the pressure is then found on the coarse scale. The pressure field within each coarse block is computed using flux boundary conditions obtained from the coarse pressure solution. Streamline-based simulation is used to move saturations forward in time. We test the method for a series of example waterflood problems and demonstrate that the method can give accurate estimates of oil production for large 3D models significantly faster than direct simulation using streamlines on the fine grid, making the method overall approximately up to 1,000 times faster than direct conventional simulation.