Volume-Surface Trees

Many algorithms in computer graphics improve their efficiency by using Hierarchical Space Subdivision Schemes (HS³), such as octrees, kD‐trees or BSP trees. Such HS³ usually provide an axis‐aligned subdivision of the 3D space embedding a scene or an object. However, the purely volume‐based behavior of these schemes often leads to strongly imbalanced surface clustering. In this article, we introduce the VS‐Tree, an alternative HS³ providing efficient and accurate surface‐based hierarchical clustering via a combination of a global 3D decomposition at coarse subdivision levels, and a local 2D decomposition at fine levels near the surface. First, we show how to efficiently construct VS‐Trees over meshes and point‐based surfaces, and analyze the improvement it offers for cluster‐based surface simplification methods. Then we propose a new surface reconstruction algorithm based on the volume‐surface classification of the VS‐Tree. This new algorithm is faster than state‐of‐the‐art reconstruction methods and provides a final semi‐regular mesh comparable to the output of remeshing algorithms.     

Removal of cyanide in aqueous solution by oxidation with hydrogen peroxide in presence of copper-impregnated activated carbon

This work is devoted to the removal of free cyanide from aqueous solution by oxidation with hydrogen peroxide H₂O₂ catalyzed by copper-impregnated activated carbon. Effects of initial molar ratio [H₂O₂]₀/[CN⁻]₀, copper-impregnated activated carbon amount, pH and the temperature on cyanide removal have been investigated.The presence of copper-impregnated activated carbon has increased the reaction rate showing thus a catalytic activity. The rate of cyanides removal increases with the raise of the initial molar ratio [H₂O₂]₀/[CN⁻]0 and decreases with the increase in the pH from 8 to 12. The increase in the copper-impregnated activated carbon amount from 1.5 to 10 g/L in reaction solution has a beneficial effect. Beyond this value, the impact of activated carbon amount is not anymore significant. The temperature does not have a significant effect between 20 and 35 °C. The four successive times re-use of catalyst shows a good stability. The kinetics of cyanide removal has been found to be of pseudo-second-order with respect to cyanide and the rate constants have been determined. This process seems very interesting because the rate of cyanides removal is very fast, the reaction does not use soluble metal catalyst and it consumes only hydrogen peroxide as chemical product.     

A reconfigurable wafer-scale memory

Describes the design and experimental results of a wafer-scale reconfigurable static memory. To achieve this, elementary memory chips are implemented on a 4-in wafer with a regular layout allowing step-and-repeat manufacturing, and the final memory is constructed with the good chips. After an external test, a cartography of good chips is established. Two algorithms, one based on distance sorting and the other one on a linear scanning of the wafer, have been developed to define an optimized global architecture with the good chips. Hard configuration of these chips is done by laser techniques. The switching technology to discard faulty elements and replace them by spares and the copper tracks to drive a large amount of current on typical 10-cm lines are described     

Assessment of Algerian sorghum protein quality [Sorghum bicolor (L.) Moench] using amino acid analysis and in vitro pepsin digestibility

To assess the protein quality and the nutritive value of seven Algerian local sorghum cultivars, the in vitro pepsin digestibility was determined, which ranged from 25.0% to 65.0%, and the amino acid composition of each cultivar was compared with other sorghum cultivars. In addition, the amino acid scores (AAS) and the protein digestibility-corrected amino acid scores (PDCAAS) were calculated. Relative to the WHO protein standard, most of the sorghum cultivars tested, scored very high AAS, with values ranging between 0.9 and 2.6 except for lysine, methionine and cysteine. The PDCAAS were high for Ain Salah cultivars AS1 and AS3, however, all other cultivars showed low values except for leucine. This study confirmed that in terms of both quantity and quality, sorghum proteins could serve as a source of essential amino acids and as a potential source of proteins in the future.     

High Dynamic Range Point Clouds for Real‐Time Relighting

Acquired 3D point clouds make possible quick modeling of virtual scenes from the real world. With modern 3D capture pipelines, each point sample often comes with additional attributes such as normal vector and color response. Although rendering and processing such data has been extensively studied, little attention has been devoted using the light transport hidden in the recorded per‐sample color response to relight virtual objects in visual effects (VFX) look‐dev or augmented reality (AR) scenarios. Typically, standard relighting environment exploits global environment maps together with a collection of local light probes to reflect the light mood of the real scene on the virtual object. We propose instead a unified spatial approximation of the radiance and visibility relationships present in the scene, in the form of a colored point cloud. To do so, our method relies on two core components: High Dynamic Range (HDR) expansion and real‐time Point‐Based Global Illumination (PBGI). First, since an acquired color point cloud typically comes in Low Dynamic Range (LDR) format, we boost it using a single HDR photo exemplar of the captured scene that can cover part of it. We perform this expansion efficiently by first expanding the dynamic range of a set of renderings of the point cloud and then projecting these renderings on the original cloud. At this stage, we propagate the expansion to the regions not covered by the renderings or with low‐quality dynamic range by solving a Poisson system. Then, at rendering time, we use the resulting HDR point cloud to relight virtual objects, providing a diffuse model of the indirect illumination propagated by the environment. To do so, we design a PBGI algorithm that exploits the GPU's geometry shader stage as well as a new mipmapping operator, tailored for G‐buffers, to achieve real‐time performances. As a result, our method can effectively relight virtual objects exhibiting diffuse and glossy physically‐based materials in real time. Furthermore, it accounts for the spatial embedding of the object within the 3D environment. We evaluate our approach on manufactured scenes to assess the error introduced at every step from the perfect ground truth. We also report experiments with real captured data, covering a range of capture technologies, from active scanning to multiview stereo reconstruction.     

Real-Time Deformation with Coupled Cages and Skeletons

Skeleton-based and cage-based deformation techniques represent the two most popular approaches to control real-time deformations of digital shapes and are, to a vast extent, complementary to one another. Despite their complementary roles, high-end modelling packages do not allow for seamless integration of such control structures, thus inducing a considerable burden on the user to maintain them synchronized. In this paper, we propose a framework that seamlessly combines rigging skeletons and deformation cages, granting artists with a real-time deformation system that operates using any smooth combination of the two approaches. By coupling the deformation spaces of cages and skeletons, we access a much larger space, containing poses that are impossible to obtain by acting solely on a skeleton or a cage. Our method is oblivious to the specific techniques used to perform skinning and cage-based deformation, securing it compatible with pre-existing tools. We demonstrate the usefulness of our hybrid approach on a variety of examples.     

Impact of platinum contamination on ferroelectric memories

Abstract

The impact of platinum contamination on the breakdown properties of gate oxide is reported. Wafers were intentionally contaminated with 1×10¹³ to 4×10¹⁴ at/cm² Pt after a 7.5 nm gate oxide growth, 300 nm poly-silicon deposition and subsequent phosphorus doping. Breakdown characteristics were evaluated using a voltage ramp method. The current-voltage curves of MOS capacitors show very few low field breakdown events, and the main field breakdown occurs at 12 MV/cm. If compared to clean wafers, platinum does not increase the defect density seriously. It is found from the E-Ramp results that platinum contamination up to 4×10¹⁴ at/cm² does not have a pronounced effect on the gate oxide integrity if the contamination occurs after front-end-of-line processing of device fabrication.     

A Survey of Simple Geometric Primitives Detection Methods for Captured 3D Data

The amount of captured 3D data is continuously increasing, with the democratization of consumer depth cameras, the development of modern multi‐view stereo capture setups and the rise of single‐view 3D capture based on machine learning. The analysis and representation of this ever growing volume of 3D data, often corrupted with acquisition noise and reconstruction artefacts, is a serious challenge at the frontier between computer graphics and computer vision. To that end, segmentation and optimization are crucial analysis components of the shape abstraction process, which can themselves be greatly simplified when performed on lightened geometric formats. In this survey, we review the algorithms which extract simple geometric primitives from raw dense 3D data. After giving an introduction to these techniques, from the acquisition modality to the underlying theoretical concepts, we propose an application‐oriented characterization, designed to help select an appropriate method based on one's application needs and compare recent approaches. We conclude by giving hints for how to evaluate these methods and a set of research challenges to be explored.     

A Survey on Data‐driven Dictionary‐based Methods for 3D Modeling

Dictionaries are very useful objects for data analysis, as they enable a compact representation of large sets of objects through the combination of atoms. Dictionary‐based techniques have also particularly benefited from the recent advances in machine learning, which has allowed for data‐driven algorithms to take advantage of the redundancy in the input dataset and discover relations between objects without human supervision or hard‐coded rules. Despite the success of dictionary‐based techniques on a wide range of tasks in geometric modeling and geometry processing, the literature is missing a principled state‐of‐the‐art of the current knowledge in this field. To fill this gap, we provide in this survey an overview of data‐driven dictionary‐based methods in geometric modeling. We structure our discussion by application domain: surface reconstruction, compression, and synthesis. Contrary to previous surveys, we place special emphasis on dictionary‐based methods suitable for 3D data synthesis, with applications in geometric modeling and design. Our ultimate goal is to enlight the fact that these techniques can be used to combine the data‐driven paradigm with design intent to synthesize new plausible objects with minimal human intervention. This is the main motivation to restrict the scope of the present survey to techniques handling point clouds and meshes, making use of dictionaries whose definition depends on the input data, and enabling shape reconstruction or synthesis through the combination of atoms.     

Forward Light Cuts: A Scalable Approach to Real‐Time Global Illumination

We present Forward Light Cuts, a novel approach to real‐time global illumination using forward rendering techniques. We focus on unshadowed diffuse interactions for the first indirect light bounce in the context of large models such as the complex scenes usually encountered in CAD application scenarios. Our approach efficiently generates and uses a multiscale radiance cache by exploiting the geometry‐specific stages of the graphics pipeline, namely the tessellator unit and the geometry shader To do so, we assimilate virtual point lights to the scene's triangles and design a stochastic decimation process chained with a partitioning strategy that accounts for both close‐by strong light reflections, and distant regions from which numerous virtual point lights collectively contribute strongly to the end pixel. Our probabilistic solution is supported by a mathematical analysis and a number of experiments covering a wide range of application scenarios. As a result, our algorithm requires no precomputation of any kind, is compatible with dynamic view points, lighting condition, geometry and materials, and scales to tens of millions of polygons on current graphics hardware.