bluuebunny/crossref_metadata_2025_split huggingface dataset:
Escherichia coli virulence patterns may help to predict vesicoureteral reflux in paediatric urinary tract infections
Authors: Hogan Julien , Mahjoub Farah , Larakeb Anis Skander , Vu Thien Hoang , Hosany Ahmad , Bensman Albert , Grimprel Emmanuel , Bingen Edouard , Bonacorsi Stéphane , Ulinski Tim 
Published: June 2015

AbstractAimUltrasound and biological tools are used to predict high‐grade vesicoureteral reflux, but other markers are needed to better select patients who need voiding cystography. Our aim was to determine whether studying Escherichia coli virulence factors would help to predict vesicoureteral reflux in patients with their first acute pyelonephritis.MethodsWe included children presenting with E. coli‐related acute pyelonephritis or cystitis. Vesicoureteral reflux was assessed by voiding cystography. Virulence factors were identified by multiplex polymerase chain reaction. Statistical analysis was performed using logistic regression and the mean c‐statistic test.ResultsWe included 198 patients: 30 with cystitis and 168 with acute pyelonephritis, including 46 with vesicoureteral reflux. High‐grade reflux was associated with acute pyelonephritis caused by the E. coli lacking virulence factors papGII (82% versus 47%, p < 0.001) or papC (85% versus 53%, p < 0.001) or belonging to phylogenetic group A or B1. When we added genetic data (lack of papGII, fyuA and phylogenetic groups) to classical predictors of vesicoureteral reflux (ultrasound examination, gender, age), the ability to predict high‐grade reflux increased, with the c‐statistic rising from 0.88 to 0.93.ConclusionBacterial virulence factors and clinical factors helped to predict high‐grade reflux and may help to avoid unnecessary voiding cystographies.
Inference for Blocked Randomization under a Selection Bias Model
Authors: Kennes Lieven N. , Rosenberger William F. , Hilgers Ralf-Dieter 
Published: June 2015

Summary
We provide an asymptotic test to analyze randomized clinical trials that may be subject to selection bias. For normally distributed responses, and under permuted block randomization, we derive a likelihood ratio test of the treatment effect under a selection bias model. A likelihood ratio test of the presence of selection bias arises from the same formulation. We prove that the test is asymptotically chi-square on one degree of freedom. These results correlate well with the likelihood ratio test of Ivanova et al. (2005, Statistics in Medicine 24, 1537–1546) for binary responses, for which they established by simulation that the asymptotic distribution is chi-square. Simulations also show that the test is robust to departures from normality and under another randomization procedure. We illustrate the test by reanalyzing a clinical trial on retinal detachment.
Breastfeeding‐Friendly Environmental Factors and Continuing Breastfeeding Until 6 Months Postpartum: 2008–2011 National Surveys in Taiwan
Authors: Lee Chia‐Chian , Chiou Shu‐Ti , Chen Li‐Chuan , Chien Li‐Yin 
Published: June 2015

AbstractBackgroundAlthough policies have been implemented to improve a breastfeeding‐friendly environment, few studies have examined the effectiveness of these policies in Taiwan. We examined progress in breastfeeding environmental factors from 2008 through 2011 in Taiwan and their association with continuing exclusive and any breastfeeding until 6 months postpartum.MethodsThis study was a secondary data analysis, using four cross‐sectional and national surveys of 1,453–12,410 postpartum women in the years 2008 through 2011. Data were collected by telephone interviews, using structured questionnaires with randomly selected postpartum women who gave birth in the indicated years. Results were weighted to enhance representativeness. Logistic regression was used to compute adjusted odds ratios for the use of breastfeeding‐friendly services on breastfeeding continuation.ResultsThe rates of breastfeeding at 6 months postpartum generally increased from 2008 to 2011, despite a drop in 2010. The use of breastfeeding‐friendly environmental factors, including breastfeeding rooms in public places or workplaces, breastfeeding consultation phone lines/websites, breastfeeding volunteers, and delivery in baby‐friendly hospitals, increased from 2008 to 2011. However, the percentage of women participating in breastfeeding support groups decreased during that period. After controlling for maternal characteristics, use of each of the breastfeeding‐friendly environmental factors was significantly and positively associated with continuing breastfeeding until 6 months postpartum. The adjusted odds ratios for breastfeeding‐friendly environmental factors ranged from 1.15 to 5.04.ConclusionsThe breastfeeding‐friendly environment and long‐term breastfeeding rates in Taiwan improved from 2008 to 2011, supporting the effectiveness of policy and public health efforts.
Designing Camera Networks by Convex Quadratic Programming
Authors: Ghanem Bernard , Cao Yuanhao , Wonka Peter 
Published: June 2015

AbstractIn this paper, we study the problem of automatic camera placement for computer graphics and computer vision applications. We extend the problem formulations of previous work by proposing a novel way to incorporate visibility constraints and camera‐to‐camera relationships. For example, the placement solution can be encouraged to have cameras that image the same important locations from different viewing directions, which can enable reconstruction and surveillance tasks to perform better. We show that the general camera placement problem can be formulated mathematically as a convex binary quadratic program (BQP) under linear constraints. Moreover, we propose an optimization strategy with a favorable trade‐off between speed and solution quality. Our solution is almost as fast as a greedy treatment of the problem, but the quality is significantly higher, so much so that it is comparable to exact solutions that take orders of magnitude more computation time. Because it is computationally attractive, our method also allows users to explore the space of solutions for variations in input parameters. To evaluate its effectiveness, we show a range of 3D results on real‐world floorplans (garage, hotel, mall, and airport).
Distilled Collections from Textual Image Queries
Authors: Averbuch‐Elor Hadar , Wang Yunhai , Qian Yiming , Gong Minglun , Kopf Johannes , Zhang Hao , Cohen‐Or Daniel 
Published: June 2015

AbstractWe present a distillation algorithm which operates on a large, unstructured, and noisy collection of internet images returned from an online object query. We introduce the notion of a distilled set, which is a clean, coherent, and structured subset of inlier images. In addition, the object of interest is properly segmented out throughout the distilled set. Our approach is unsupervised, built on a novel clustering scheme, and solves the distillation and object segmentation problems simultaneously. In essence, instead of distilling the collection of images, we distill a collection of loosely cutout foreground “shapes”, which may or may not contain the queried object. Our key observation, which motivated our clustering scheme, is that outlier shapes are expected to be random in nature, whereas, inlier shapes, which do tightly enclose the object of interest, tend to be well supported by similar shapes captured in similar views. We analyze the commonalities among candidate foreground segments, without aiming to analyze their semantics, but simply by clustering similar shapes and considering only the most significant clusters representing non‐trivial shapes. We show that when tuned conservatively, our distillation algorithm is able to extract a near perfect subset of true inliers. Furthermore, we show that our technique scales well in the sense that the precision rate remains high, as the collection grows. We demonstrate the utility of our distillation results with a number of interesting graphics applications.
Interactive Generation of Realistic Facial Wrinkles from Sketchy Drawings
Authors: Kim Hyeon‐Joong , Öztireli A. Cengiz , Shin Il‐Kyu , Gross Markus , Choi Soo‐Mi 
Published: June 2015

AbstractSynthesizing facial wrinkles has been tackled either by a long process of manual sculpting on 3D models, or using automatic methods that do not allow for user interaction or artistic expression. In this paper, we propose a method that accepts interactive sketchy drawings depicting wrinkle patterns, and synthesizes realistic looking wrinkles on faces. The method inherits the simplicity of sketching, making it possible for artists as well as novice users to generate realistic facial detail very efficiently, allowing fast preview for physical makeup, or aging simulations for fun and professional applications. All strokes are used to infer the wrinkles, retaining the expressiveness of the sketches and realism of the final result at the same time. This is achieved by designing novel multi‐scale statistics tailored to the wrinkle geometry and coupled to the sketch interpretation method. The statistics capture the cross‐sectional profiles of wrinkles at different scales and parts of a face. The strokes are augmented with the statistics extracted from given example face models, and applied to an input face model interactively. The interface gives the user control over the shapes and scales of wrinkles via sketching while adding extra details required for realism automatically.
3D Fabrication of 2D Mechanisms
Authors: Hergel Jean , Lefebvre Sylvain 
Published: June 2015

AbstractThe success of physics sandbox applications and physics‐based puzzle games is a strong indication that casual users and hobbyists enjoy designing mechanisms, for educational or entertainment purposes. In these applications, a variety of mechanisms are designed by assembling two‐dimensional shapes, creating gears, cranks, cams, and racks. The experience is made enjoyable by the fact that the user does not need to worry about the intricate geometric details that would be necessary to produce a real mechanism.In this paper, we propose to start from such casual designs of mechanisms and turn them into a 3D model that can be printed onto widely available, inexpensive filament based 3D printers. Our intent is to empower the users of such tools with the ability to physically realize their mechanisms and see them operate in the real world. To achieve this goal we tackle several challenges. The input 2D mechanism allows for some parts to overlap during simulation. These overlapping parts have to be resolved into non‐intersecting 3D parts in the real mechanism. We introduce a novel scheme based on the idea of including moving parts into one another whenever possible. This reduces bending stresses on axles compared to previous methods. Our approach supports sliding parts and arbitrarily shaped mechanical parts in the 2D input. The exact 3D shape of the parts is inferred from the 2D input and the simulation of the mechanism, using boolean operations between shapes. The input mechanism is often simply attached to the background. We automatically synthesize a chassis by formulating a topology optimization problem, taking into account the stresses exerted by the mechanism on the chassis through time.
Shape‐from‐Operator: Recovering Shapes from Intrinsic Operators
Authors: Boscaini Davide , Eynard Davide , Kourounis Drosos , Bronstein Michael M. 
Published: June 2015

AbstractWe formulate the problem of shape‐from‐operator (SfO), recovering an embedding of a mesh from intrinsic operators defined through the discrete metric (edge lengths). Particularly interesting instances of our SfO problem include: shape‐from‐Laplacian, allowing to transfer style between shapes; shape‐from‐difference operator, used to synthesize shape analogies; and shape‐from‐eigenvectors, allowing to generate ‘intrinsic averages’ of shape collections. Numerically, we approach the SfO problem by splitting it into two optimization sub‐problems: metric‐from‐operator (reconstruction of the discrete metric from the intrinsic operator) and embedding‐from‐metric (finding a shape embedding that would realize a given metric, a setting of the multidimensional scaling problem). We study numerical properties of our problem, exemplify it on several applications, and discuss its imitations.
Self Tuning Texture Optimization
Authors: Kaspar Alexandre , Neubert Boris , Lischinski Dani , Pauly Mark , Kopf Johannes 
Published: June 2015

AbstractThe goal of example‐based texture synthesis methods is to generate arbitrarily large textures from limited exemplars in order to fit the exact dimensions and resolution required for a specific modeling task. The challenge is to faithfully capture all of the visual characteristics of the exemplar texture, without introducing obvious repetitions or unnatural looking visual elements. While existing non‐parametric synthesis methods have made remarkable progress towards this goal, most such methods have been demonstrated only on relatively low‐resolution exemplars. Real‐world high resolution textures often contain texture details at multiple scales, which these methods have difficulty reproducing faithfully. In this work, we present a new general‐purpose and fully automatic self‐tuning non‐parametric texture synthesis method that extends Texture Optimization by introducing several key improvements that result in superior synthesis ability. Our method is able to self‐tune its various parameters and weights and focuses on addressing three challenging aspects of texture synthesis: (i) irregular large scale structures are faithfully reproduced through the use of automatically generated and weighted guidance channels; (ii) repetition and smoothing of texture patches is avoided by new spatial uniformity constraints; (iii) a smart initialization strategy is used in order to improve the synthesis of regular and near‐regular textures, without affecting textures that do not exhibit regularities. We demonstrate the versatility and robustness of our completely automatic approach on a variety of challenging high‐resolution texture exemplars.
Scalable Partitioning for Parallel Position Based Dynamics
Authors: Fratarcangeli M. , Pellacini F. 
Published: June 2015

AbstractWe introduce a practical partitioning technique designed for parallelizing Position Based Dynamics, and exploiting the ubiquitous multi‐core processors present in current commodity GPUs. The input is a set of particles whose dynamics is influenced by spatial constraints. In the initialization phase, we build a graph in which each node corresponds to a constraint and two constraints are connected by an edge if they influence at least one common particle. We introduce a novel greedy algorithm for inserting additional constraints (phantoms) in the graph such that the resulting topology is ‐colourable, where is an arbitrary number. We color the graph, and the constraints with the same color are assigned to the same partition. Then, the set of constraints belonging to each partition is solved in parallel during the animation phase. We demonstrate this by using our partitioning technique; the performance hit caused by the GPU kernel calls is significantly decreased, leaving unaffected the visual quality, robustness and speed of serial position based dynamics.
A Cut‐Cell Geometric Multigrid Poisson Solver for Fluid Simulation
Authors: Weber Daniel , Mueller‐Roemer Johannes , Stork André , Fellner Dieter 
Published: June 2015

AbstractWe present a novel multigrid scheme based on a cut‐cell formulation on regular staggered grids which generates compatible systems of linear equations on all levels of the multigrid hierarchy. This geometrically motivated formulation is derived from a finite volume approach and exhibits an improved rate of convergence compared to previous methods. Existing fluid solvers with voxelized domains can directly benefit from this approach by only modifying the representation of the non‐fluid domain. The necessary building blocks are fully parallelizable and can therefore benefit from multi‐ and many‐core architectures.
T‐SAH: Animation Optimized Bounding Volume Hierarchies
Authors: Bittner J. , Meister D. 
Published: June 2015

AbstractWe propose a method for creating a bounding volume hierarchy (BVH) that is optimized for all frames of a given animated scene. The method is based on a novel extension of surface area heuristic to temporal domain (T‐SAH). We perform iterative BVH optimization using T‐SAH and create a single BVH accounting for scene geometry distribution at different frames of the animation. Having a single optimized BVH for the whole animation makes our method extremely easy to integrate to any application using BVHs, limiting the per‐frame overhead only to refitting the bounding volumes. We evaluated the T‐SAH optimized BVHs in the scope of real‐time GPU ray tracing. We demonstrate, that our method can handle even highly complex inputs with large deformations and significant topology changes. The results show, that in a vast majority of tested scenes our method provides significantly better run‐time performance than traditional SAH and also better performance than GPU based per‐frame BVH rebuild.
Partitioned Shadow Volumes
Authors: Gerhards J. , Mora F. , Aveneau L. , Ghazanfarpour D. 
Published: June 2015

AbstractReal‐time shadows remain a challenging problem in computer graphics. In this context, shadow algorithms generally rely either on shadow mapping or shadow volumes. This paper rediscovers an old class of algorithms that build a binary space partition over the shadow volumes. For almost 20 years, such methods have received little attention as they have been considered lacking of both robustness and efficiency. We show that these issues can be overcome, leading to a simple and robust shadow algorithm. Hence we demonstrate that this kind of approach can reach a high level of performance. Our algorithm uses a new partitioning strategy which avoids any polygon clipping. It relies on a Ternary Object Partitioning tree, a new data structure used to find if an image point is shadowed. Our method works on a triangle soup and its memory footprint is fixed. Our experiments show that it is efficient and robust, including for finely tessellated models.
General and Robust Error Estimation and Reconstruction for Monte Carlo Rendering
Authors: Bauszat Pablo , Eisemann Martin , Eisemann Elmar , Magnor Marcus 
Published: June 2015

AbstractAdaptive filtering techniques have proven successful in handling non‐uniform noise in Monte‐Carlo rendering approaches. A recent trend is to choose an optimal filter per pixel from a selection of non spatially‐varying filters. Nonetheless, the best filter choice is difficult to predict in the absence of a reference rendering. Our approach relies on the observation that the reconstruction error is locally smooth for a given filter. Hence, we propose to construct a dense error prediction from a small set of sparse but robust estimates. The filter selection is then formulated as a non‐local optimization problem, which we solve via graph cuts, to avoid visual artifacts due to inconsistent filter choices. Our approach does not impose any restrictions on the used filters, outperforms previous state‐of‐the‐art techniques and provides an extensible framework for future reconstruction techniques.
Selective Degree Elevation for Multi‐Sided Bézier Patches
Authors: Smith J. , Schaefer S. 
Published: June 2015

AbstractThis paper presents a method to selectively elevate the degree of an S‐Patch of arbitrary dimension. We consider not only S‐Patches with 2D domains but 3D and higher‐dimensional domains as well, of which volumetric cage deformations are a subset. We show how to selectively insert control points of a higher degree patch into a lower degree patch while maintaining the polynomial reproduction order of the original patch. This process allows the user to elevate the degree of only one portion of the patch to add new degrees of freedom or maintain continuity with adjacent patches without elevating the degree of the entire patch, which could create far more degrees of freedom than necessary. Finally we show an application to cage‐based deformations where we increase the number of control points by elevating the degree of a subset of cage faces. The result is a cage deformation with higher degree triangular Bézier functions on a subset of cage faces but no interior control points.
Statics Aware Grid Shells
Authors: Pietroni Nico , Tonelli Davide , Puppo Enrico , Froli Maurizio , Scopigno Roberto , Cignoni Paolo 
Published: June 2015

AbstractWe introduce a framework for the generation of polygonal gridshell architectural structures, whose topology is designed in order to excel in static performances. We start from the analysis of stress on the input surface and we use the resulting tensor field to induce an anisotropic nonEuclidean metric over it. This metric is derived by studying the relation between the stress tensor over a continuous shell and the optimal shape of polygons in a corresponding gridshell. Polygonal meshes with uniform density and isotropic cells under this metric exhibit variable density and anisotropy in Euclidean space, thus achieving a better distribution of the strain energy over their elements. Meshes are further optimized taking into account symmetry and regularity of cells to improve aesthetics. We experiment with quad meshes and hexdominant meshes, demonstrating that our gridshells achieve better static performances than stateoftheart gridshells.
Recent Advances in Adaptive Sampling and Reconstruction for Monte Carlo Rendering
Authors: Zwicker M. , Jarosz W. , Lehtinen J. , Moon B. , Ramamoorthi R. , Rousselle F. , Sen P. , Soler C. , Yoon S.‐E. 
Published: June 2015

AbstractMonte Carlo integration is firmly established as the basis for most practical realistic image synthesis algorithms because of its flexibility and generality. However, the visual quality of rendered images often suffers from estimator variance, which appears as visually distracting noise. Adaptive sampling and reconstruction algorithms reduce variance by controlling the sampling density and aggregating samples in a reconstruction step, possibly over large image regions. In this paper we survey recent advances in this area. We distinguish between “a priori” methods that analyze the light transport equations and derive sampling rates and reconstruction filters from this analysis, and “a posteriori” methods that apply statistical techniques to sets of samples to drive the adaptive sampling and reconstruction process. They typically estimate the errors of several reconstruction filters, and select the best filter locally to minimize error. We discuss advantages and disadvantages of recent state‐of‐the‐art techniques, and provide visual and quantitative comparisons. Some of these techniques are proving useful in real‐world applications, and we aim to provide an overview for practitioners and researchers to assess these approaches. In addition, we discuss directions for potential further improvements.