bluuebunny/crossref_metadata_2025_split huggingface dataset:
What is the effect of climate change on marine fish biodiversity in an area of low connectivity, the Baltic Sea?
Authors: Hiddink Jan Geert , Coleby Chris 
Published: July 2011

ABSTRACTAim  Climate change could result in an increase in species richness because large‐scale biogeography suggests that more species could be gained from equatorial regions than may be lost pole‐ward. However, the colonization of newly available habitat may lag behind the rate dictated by climatic warming if there exists of a lack of connectivity between ‘donor’ and receiving areas. The objective of this study was to compare how regional warming affected the biodiversity of marine fish in areas that differed in their connectivity in the Baltic Sea.Location  North‐east Atlantic, Kattegat and Baltic Sea.Methods  The total species richness and the mean species richness from scientific surveys were related to changes in temperature and salinity. Changes in the extent of the distribution of individual fish species were related to the latitudinal distribution, salinity tolerance, maximum body size and exploitation status to assess to what extent climate change and fishing impacts could explain changes in species richness in the Baltic.Results  Rising temperatures in the well‐connected Kattegat correlated to an increase in the species richness of fish, due to an increase in low‐latitude species. Unexpectedly, species richness in the poorly connected Baltic Sea also increased. However, the increase seems to be related to higher salinity rather than temperature and there was no influx of low‐latitude species.Main conclusions  These results do not support the hypothesis that low‐connectivity areas are less likely to see increases in species richness in response to warming. This indicates that the effect of climate change on biodiversity may be more difficult to predict in areas of low connectivity than in well‐connected areas.
An Energy‐Conserving Hair Reflectance Model
Authors: d'Eon Eugene , Francois Guillaume , Hill Martin , Letteri Joe , Aubry Jean‐Marie 
Published: July 2011

AbstractWe present a reflectance model for dielectric cylinders with rough surfaces such as human hair fibers. Our model is energy conserving and can evaluate arbitrarily many orders of internal reflection. Accounting for compression and contraction of specular cones produces a new longitudinal scattering function which is non‐Gaussian and includes an off‐specular peak. Accounting for roughness in the azimuthal direction leads to an integral across the hair fiber which is efficiently evaluated using a Gaussian quadrature. Solving cubic equations is avoided, caustics are included in the model in a consistent fashion, and more accurate colors are predicted by considering many internal pathways.
Stratified Sampling for Stochastic Transparency
Authors: Laine Samuli , Karras Tero 
Published: July 2011

AbstractThe traditional method of rendering semi‐transparent surfaces using alpha blending requires sorting the surfaces in depth order. There are several techniques for order‐independent transparency, but most require either unbounded storage or can be fragile due to forced compaction of information during rendering. Stochastic transparency works in a fixed amount of storage and produces results with the correct expected value. However, carelessly chosen sampling strategies easily result in high variance of the final pixel colors, showing as noise in the image. In this paper, we describe a series of improvements to stochastic transparency that enable stratified sampling in both spatial and alpha domains. As a result, the amount of noise in the image is significantly reduced, while the result remains unbiased.
Efficient Computation of Blue Noise Point Sets through Importance Sampling
Authors: Kalantari Nima Khademi , Sen Pradeep 
Published: July 2011

AbstractDart‐throwing can generate ideal Poisson‐disk distributions with excellent blue noise properties, but is very computationally expensive if a maximal point set is desired. In this paper, we observe that the Poisson‐disk sampling problem can be posed in terms of importance sampling by representing the available space to be sampled as a probability density function (pdf). This allows us to develop an efficient algorithm for the generation of maximal Poisson‐disk distributions with quality similar to naïve dart‐throwing but without rejection of samples. In our algorithm, we first position samples in one dimension based on its marginal cumulative distribution function (cdf). We then throw samples in the other dimension only in the regions which are available for sampling. After each 2D sample is placed, we update the cdf and data structures to keep track of the available regions. In addition to uniform sampling, our method is able to perform variable‐density sampling with small modifications. Finally, we also propose a new min‐conflict metric for variable‐density sampling which results in better adaptation of samples to the underlying importance field.
Silhouette‐Aware Warping for Image‐Based Rendering
Authors: Chaurasia Gaurav , Sorkine Olga , Drettakis George 
Published: July 2011

AbstractImage‐based rendering (IBR) techniques allow capture and display of 3D environments using photographs. Modern IBR pipelines reconstruct proxy geometry using multi‐view stereo, reproject the photographs onto the proxy and blend them to create novel views. The success of these methods depends on accurate 3D proxies, which are difficult to obtain for complex objects such as trees and cars. Large number of input images do not improve reconstruction proportionally; surface extraction is challenging even from dense range scans for scenes containing such objects. Our approach does not depend on dense accurate geometric reconstruction; instead we compensate for sparse 3D information by variational image warping. In particular, we formulate silhouette‐aware warps that preserve salient depth discontinuities. This improves the rendering of difficult foreground objects, even when deviating from view interpolation. We use a semi‐automatic step to identify depth discontinuities and extract a sparse set of depth constraints used to guide the warp. Our framework is lightweight and results in good quality IBR for previously challenging environments.
ManyLoDs: Parallel Many‐View Level‐of‐Detail Selection for Real‐Time Global Illumination
Authors: Hollander Matthias , Ritschel Tobias , Eisemann Elmar , Boubekeur Tamy 
Published: July 2011

AbstractLevel‐of‐Detail structures are a key component for scalable rendering. Built from raw 3D data, these structures are often defined as Bounding Volume Hierarchies, providing coarse‐to‐fine adaptive approximations that are well‐adapted for many‐view rasterization. Here, the total number of pixels in each view is usually low, while the cost of choosing the appropriate LoD for each view is high. This task represents a challenge for existing GPU algorithms. We propose ManyLoDs, a new GPU algorithm to efficiently compute many LoDs from a Bounding Volume Hierarchy in parallel by balancing the workload within and among LoDs. Our approach is not specific to a particular rendering technique, can be used on lazy representations such as polygon soups, and can handle dynamic scenes. We apply our method to various many‐view rasterization applications, including Instant Radiosity, Point‐Based Global Illumination, and reflection/refraction mapping. For each of these, we achieve real‐time performance in complex scenes at high resolutions.
Anaglyph Stereo Without Ghosting
Authors: Sanftmann H. , Weiskopf D. 
Published: July 2011

AbstractAnaglyph stereo provides a low‐budget solution to viewing stereoscopic images. However, it may suffer from ghosting and bad color reproduction. Here we address the first issue. We present a novel technique to perceptually calibrate an anaglyph stereoscopic system and to use the calibration to eliminate ghosting from the anaglyph image. We build a model based on luminance perception by the left and right eyes through the anaglyph glasses. We do not rely on power spectra of a monitor or on transmission spectra of anaglyph glasses, but show how the five parameters of our model can be captured with just a few measurements within a minute. We present how full color, half color, and gray anaglyphs can be rendered with our technique and compare them to the traditional method.
A Physically Plausible Model for Light Emission from Glowing Solid Objects
Authors: Wilkie A. , Weidlich A. 
Published: July 2011

AbstractThe emissive properties of glowing solid objects appear to be something that the graphics community has not considered in depth before. While the volumetric emission of plasma, i.e. flames, has been discussed numerous times, and while the emission characteristics of entire luminaires can be handled via IESNA profiles, the exact appearance of glowing solid objects appears to have eluded detailed scrutiny so far. In this paper, we discuss the theoretical background to thermally induced light emission of objects, describe how one can handle this behaviour with very little effort in a physically based rendering system, and provide examples for the visual importance of handling this in a plausible fashion.
Variable Bit Rate GPU Texture Decompression
Authors: Olano M. , Baker D. , Griffin W. , Barczak J. 
Published: July 2011

AbstractVariable bit rate compression can achieve better quality and compression rates than fixed bit rate methods. None the less, GPU texturing uses lossy fixed bit rate methods like DXT to allow random access and on‐the‐fly decompression during rendering. Changes in games and GPUs since DXT was developed make its compression artifacts less acceptable, and texture bandwidth less of an issue, but texture size is a serious and growing problem. Games use a large total volume of texture data, but have a much smaller active set. We present a new paradigm that separates GPU decompression from rendering. Rendering is from uncompressed data, avoiding the need for random access decompression. We demonstrate this paradigm with a new variable bit rate lossy texture compression algorithm that is well suited to the GPU, including a new GPU‐friendly formulation of range decoding, and a new texture compression scheme averaging 12.4:1 lossy compression ratio on 471 real game textures with a quality level similar to traditional DXT compression. The total game texture set are stored in the GPU in compressed form, and decompressed for use in a fraction of a second per scene.
Efficient Packing of Arbitrary Shaped Charts for Automatic Texture Atlas Generation
Authors: Nöll T. , Strieker D. 
Published: July 2011

AbstractTexture atlases are commonly used as representations for mesh parameterizations in numerous applications including texture and normal mapping. Therefore, packing is an important post‐processing step that tries to place and orient the single parameterizations in a way that the available space is used as efficiently as possible. However, since packing is NP hard, only heuristics can be used in practice to find near‐optimal solutions. In this publication we introduce the new search space of modulo valid packings. The key idea thereby is to allow the texture charts to wrap around in the atlas. By utilizing this search space we propose a new algorithm that can be used in order to automatically pack texture atlases. In the evaluation section we show that our algorithm achieves solutions with a significantly higher packing efficiency when compared to the state of the art, especially for complex packing problems.
Least Squares Vertex Baking
Authors: Kavan L. , Bargteil A.W. , Sloan P.‐P. 
Published: July 2011

AbstractWe investigate the representation of signals defined on triangle meshes using linearly interpolated vertex attributes. Compared to texture mapping, storing data only at vertices yields significantly lower memory overhead and less expensive runtime reconstruction. However, standard approaches to determine vertex values such as point sampling or averaging triangle samples lead to suboptimal approximations. We discuss how an optimal solution can be efficiently calculated using continuous least‐squares. In addition, we propose a regularization term that allows us to minimize gradient discontinuities and mach banding artifacts while staying close to the optimum. Our method has been integrated in a game production lighting tool and we present examples of representing signals such as ambient occlusion and precomputed radiance transfer in real game scenes, where vertex baking was used to free up resources for other game components.
Direct Ray Tracing of Phong Tessellation
Authors: Ogaki Shinji , Tokuyoshi Yusuke 
Published: July 2011

AbstractThere are two major ways of calculating ray and parametric surface intersections in rendering. The first is through the use of tessellated triangles, and the second is to use parametric surfaces together with numerical methods such as Newton's method. Both methods are computationally expensive and complicated to implement. In this paper, we focus on Phong Tessellation and introduce a simple direct ray tracing method for Phong Tessellation. Our method enables rendering smooth surfaces in a computationally inexpensive yet robust way.
A Ray Tracing Approach to Diffusion Curves
Authors: Bowers John C. , Leahey Jonathan , Wang Rui 
Published: July 2011

AbstractDiffusion curves [OBW*08] provide a flexible tool to create smooth‐shaded images from curves defined with colors. The resulting image is typically computed by solving a Poisson equation that diffuses the curve colors to the interior of the image. In this paper we present a new method for solving diffusion curves by using ray tracing. Our approach is analogous to final gathering in global illumination, where the curves define source radiance whose visible contribution will be integrated at a shading pixel to produce a color using stochastic ray tracing. Compared to previous work, the main benefit of our method is that it provides artists with extended flexibility in achieving desired image effects. Specifically, we introduce generalized curve colors called shaders that allow for the seamless integration of diffusion curves with classic 2D graphics including vector graphics (e.g. gradient fills) and raster graphics (e.g. patterns and textures). We also introduce several extended curve attributes to customize the contribution of each curve. In addition, our method allows any pixel in the image to be independently evaluated, without having to solve the entire image globally (as required by a Poisson‐based approach). Finally, we present a GPU‐based implementation that generates solution images at interactive rates, enabling dynamic curve editing. Results show that our method can easily produce a variety of desirable image effects.
Coherent Out‐of‐Core Point‐Based Global Illumination
Authors: Kontkanen Janne , Tabellion Eric , Overbeck Ryan S. 
Published: July 2011

AbstractWe describe a new technique for coherent out‐of‐core point‐based global illumination and ambient occlusion. Point‐based global illumination (PBGI) is used in production to render tremendously complex scenes, so in‐core storage of point and octree data structures quickly becomes a problem. However, a simple out‐of‐core extension of a classical top‐down octree building algorithm would be extremely inefficient due to large amount of I/O required. Our method extends previous PBGI algorithms with an out‐of‐core technique that uses minimal I/O and stores data on disk compactly and in coherent chunks for later access during shading. Using properties of a space‐filling Z‐curve, we are able to preprocess the data in two passes: an external ID‐sort and an octree construction pass.
Guided Image Filtering for Interactive High‐quality Global Illumination
Authors: Bauszat Pablo , Eisemann Martin , Magnor Marcus 
Published: July 2011

AbstractInteractive computation of global illumination is a major challenge in current computer graphics research. Global illumination heavily affects the visual quality of generated images. It is therefore a key attribute for the perception of photo‐realistic images. Path tracing is able to simulate the physical behaviour of light using Monte Carlo techniques. However, the computational burden of this technique prohibits interactive rendering times on standard commodity hardware in high‐quality. Trying to solve the Monte Carlo integration with fewer samples results in characteristic noisy images. Global illumination filtering methods take advantage of the fact that the integral for neighbouring pixels may be very similar. Averaging samples of similar characteristics in screen‐space may approximate the correct integral, but may result in visible outliers. In this paper, we present a novel path tracing pipeline based on an edge‐aware filtering method for the indirect illumination which produces visually more pleasing results without noticeable outliers. The key idea is not to filter the noisy path traced images but to use it as a guidance to filter a second image composed from characteristic scene attributes that do not contain noise by default. We show that our approach better approximates the Monte Carlo integral compared to previous methods. Since the computation is carried out completely in screen‐space it is therefore applicable to fully dynamic scenes, arbitrary lighting and allows for high‐quality path tracing at interactive frame rates on commodity hardware.
Serum and CSF PDGF‐AA and FGF‐2 in relapsing‐remitting multiple sclerosis: a case–control study
Authors: Harirchian M. H. , Tekieh A. H. , Modabbernia A. , Aghamollaii V. , Tafakhori A. , Ghaffarpour M. , Sahraian M. A. , Naji M. , Yazdanbakhsh M. 
Published: July 2011

Background and purpose:  Fibroblast growth factor‐2 (FGF‐2) and platelet‐derived growth factor‐A (PDGF‐AA) are potent modulators of oligodendrocytes, the main responsible cells for myelin regeneration. We measured FGF‐2 and PDGF‐AA in the sera and cerebrospinal fluid (CSF) of patients with relapsing‐remitting multiple sclerosis (RR‐MS) and compared these values with control subjects.Methods:  Twenty‐three patients with RR‐MS and 23 subjects without inflammatory and demyelinating diseases were included. Serum samples of the patients were collected in both relapse and remission phases and were analyzed with ELISA method. CSF was drawn during the relapse period. Blood and CSF were drawn from control subjects for comparison. Wilcoxon and Mann–Whitney U‐test and Spearman’s rank correlation were used for analysis. P values of <0.05 were considered significant.Results:  Age and sex distribution were similar in both groups. Serum values of FGF‐2 were higher in relapse phase compared with remission phase, with a trend toward significance (P = 0.052). CSF PDGF‐AA showed significant negative correlation with disease duration (correlation coefficient = −0.58, P = 0.004). Serum levels of PDGF did not differ between two phases significantly. There was no difference in serum and CSF values of these factors between patients and controls. When we compared patients with prolonged disease with controls, a significant difference between the CSF levels of PDGF‐AA was observed (mean ± SEM 2.78 ± 0.8 in controls vs. 0.55 ± 0.29 in patients with MS ≥ 2 years, P < 0.05).Conclusion:  Our study was the first to show that CSF PDGF‐AA is related to disease duration. Supporting previous findings we showed that serum and CSF levels of these factors are weak indicators of disease severity.
A comprehensive investigation of memory impairment in attention deficit hyperactivity disorder and oppositional defiant disorder
Authors: Rhodes Sinéad M. , Park Joanne , Seth Sarah , Coghill David R. 
Published: July 2011

Background:  We conducted a comprehensive and systematic assessment of memory functioning in drug‐naïve boys with attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD).Methods:  Boys performed verbal and spatial working memory (WM) component (storage and central executive) and verbal and spatial storage load tasks, and the spatial span, spatial executive WM, spatial recognition memory and verbal recognition memory tasks from the Cambridge Neuropsychological Test Automated Battery. Groups comprised: (a) ADHD only (N = 21); (b) ADHD+ODD (N = 27); (c) ODD only (N = 21); and (d) typically developing (TYP) boys (N = 26). Groups were matched for age (M = 9.7 years) and sex (all boys).Results:  Confirmatory factor analyses confirmed the presence of five factors: verbal functioning, spatial functioning, WM storage, WM central executive and long‐term memory (LTM). All three clinical groups demonstrated impaired memory performance. Boys with ODD and ODD+ADHD but not ADHD alone performed poorly on verbal memory tasks, whilst all three clinical groups showed impaired performance on spatial memory tasks. All three clinical groups performed poorly on the storage and central executive WM factors and the LTM factor.Conclusions:  ADHD and ODD are characterised by impaired performance storage and central executive WM tasks and LTM tasks. This is, we believe, the first report of impaired WM and LTM performance in ODD. This study suggests that verbal memory difficulties are more closely associated with ODD than ADHD symptoms and that combined ADHD+ODD represents a true comorbidity. The data also support a small but growing number of suggestions in the literature of impaired LTM in ADHD.
Staying cool, keeping strong: incubation temperature affects performance in a freshwater turtle
Authors: Micheli‐Campbell M. A. , Campbell H. A. , Cramp R. L. , Booth D. T. , Franklin C. E. 
Published: July 2011

AbstractIt is unclear how predicted rises in ambient temperature associated with climate change will impact upon the survivorship of oviparous reptiles. Given that the incubation temperature can influence hatchling phenotype, understanding how elevated temperatures during development can affect the ability of hatchlings to undertake routine behaviours is important, especially for threatened species. Here we tested if raising mean incubation temperature above natural levels altered the physiology of hatchlings to an extent that behavioural function was impaired. Firstly, incubation temperatures were recorded from nests of the freshwater turtle (Elusor macrurus) in the wild, and the observed thermal range (26–31 °C) used to define the experimental protocol. Then, freshly laid E. macrurus eggs were collected and incubated at three constant temperatures (26, 29 and 32 °C). Embryos incubated at 32 °C had the lowest hatching success. Those that did hatch were smaller than the other groups and had a reduced post‐hatch growth rate. On land, the ability of hatchling turtles to right themselves is critical, and the turtles incubated at 32 °C took 30‐times longer to do this than those incubated at 26 °C. Once in the water, hatchling turtles must be able to swim effectively to evade predation and obtain food items. During swimming trials the 32 °C group exhibited a lower mean stroke force (10.5±0.3 mN) and spent less time swimming (133.7±17.7 s) compared with hatchlings incubated at 29 °C (13.4±0.4 mN, 281.3±25.7 s) and 26 °C (15.7±0.5 mN, 270.8±28.5 s). The results of the present study illustrate that even slight rises in the mean incubation temperature, over that observed in the wild, can impact upon a hatchling's performance.