bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clean color: Improving multi‐filament 3D prints
Authors: Hergel Jean , Lefebvre Sylvain 
Published: June 2014

AbstractFused Filament Fabrication is an additive manufacturing process by which a 3D object is created from plastic filament. The filament is pushed through a hot nozzle where it melts. The nozzle deposits plastic layer after layer to create the final object. This process has been popularized by the RepRap community.Several printers feature multiple extruders, allowing objects to be formed from multiple materials or colors. The extruders are mounted side by side on the printer carriage. However, the print quality suffers when objects with color patterns are printed – a disappointment for designers interested in 3D printing their colored digital models. The most severe issue is the oozing of plastic from the idle extruders: Plastics of different colors bleed onto each other giving the surface a smudged aspect, excess strings oozing from the extruder deposit on the surface, and holes appear due to this missing plastic. Fixing this issue is difficult: increasing the printing speed reduces oozing but also degrades surface quality – on large prints the required speed level become impractical. Adding a physical mechanism increases cost and print time as extruders travel to a cleaning station.Instead, we rely on software and exploit degrees of freedom of the printing process. We introduce three techniques that complement each other in improving the print quality significantly. We first reduce the impact of oozing plastic by choosing a better azimuth angle for the printed part. We build a disposable rampart in close proximity of the part, giving the extruders the opportunity to wipe oozing strings and refill with hot plastic. We finally introduce a toolpath planner avoiding and hiding most of the defects due to oozing, and seamlessly integrating the rampart. We demonstrate our technique on several challenging multiple color prints, and show that our tool path planner improves the surface finish of single color prints as well.
Efficient enforcement of hard articulation constraints in the presence of closed loops and contacts
Authors: Tomcin Robin , Sibbing Dominik , Kobbelt Leif 
Published: June 2014

AbstractIn rigid body simulation, one must distinguish between contacts (so‐called unilateral constraints) and articulations (bilateral constraints). For contacts and friction, iterative solution methods have proven most useful for interactive applications, often in combination with Shock‐Propagation in cases with strong interactions between contacts (such as stacks), prioritizing performance and plausibility over accuracy. For articulation constraints, direct solution methods are preferred, because one can rely on a factorization with linear time complexity for tree‐like systems, even in ill‐conditioned cases caused by large mass‐ratios or high complexity. Despite recent advances, combining the advantages of direct and iterative solution methods wrt. performance has proven difficult and the intricacy of articulations in interactive applications is often limited by the convergence speed of the iterative solution method in the presence of closed kinematic loops (i.e. auxiliary constraints) and contacts. We identify common performance bottlenecks in the dynamic simulation of unilateral and bilateral constraints and are able to present a simulation method, that scales well in the number of constraints even in ill‐conditioned cases with frictional contacts, collisions and closed loops in the kinematic graph. For cases where many joints are connected to a single body, we propose a technique to increase the sparsity of the positive definite linear system. A solution to these bottlenecks is presented in this paper to make the simulation of a wider range of mechanisms possible in real‐time without extensive parameter tuning.
On‐line real‐time physics‐based predictive motion control with balance recovery
Authors: Han Daseong , Noh Junyong , Jin Xiaogang , S. Shin Joseph , Y. Shin Sung 
Published: June 2014

AbstractIn this paper, we present an on‐line real‐time physics‐based approach to motion control with contact repositioning based on a low‐dimensional dynamics model using example motion data. Our approach first generates a reference motion in run time according to an on‐line user request by transforming an example motion extracted from a motion library. Guided by the reference motion, it repeatedly generates an optimal control policy for a small time window one at a time for a sequence of partially overlapping windows, each covering a couple of footsteps of the reference motion, which supports an on‐line performance. On top of this, our system dynamics and problem formulation allow to derive closed‐form derivative functions by exploiting the low‐dimensional dynamics model together with example motion data. These derivative functions and their sparse structures facilitate a real‐time performance. Our approach also allows contact foot repositioning so as to robustly respond to an external perturbation or an environmental change as well as to perform locomotion tasks such as stepping on stones effectively.
IISPH‐FLIP for incompressible fluids
Authors: Cornelis Jens , Ihmsen Markus , Peer Andreas , Teschner Matthias 
Published: June 2014

AbstractWe propose to use Implicit Incompressible Smoothed Particle Hydrodynamics (IISPH) for pressure projection and boundary handling in Fluid‐Implicit‐Particle (FLIP) solvers for the simulation of incompressible fluids. This novel combination addresses two issues of existing SPH and FLIP solvers, namely mass preservation in FLIP and efficiency and memory consumption in SPH. First, the SPH component enables the simulation of incompressible fluids with perfect mass preservation. Second, the FLIP component efficiently enriches the SPH component with detail that is comparable to a standard SPH simulation with the same number of particles, while improving the performance by a factor of 7 and significantly reducing the memory consumption. We demonstrate that the proposed IISPH‐FLIP solver can simulate incompressible fluids with a quantifiable, imperceptible density deviation below 0.1%. We show large‐scale scenarios with up to 160 million particles that have been processed on a single desktop PC using only 15GB of memory. One‐ and two‐way coupled solids are illustrated.
Rate‐distortion optimized compression of motion capture data
Authors: Váša L. , Brunnett G. 
Published: June 2014

AbstractLossy compression of motion capture data can alleviate the problems of efficient storage and transmission by exploiting the redundancy and the superfluous precision of the data. When considering the acceptable amount of distortion, perceptual issues have to be taken into account. Current state of the art methods reduce the data rate required for high quality storage of motion capture data using various techniques. Most of them, however, do not use the common tools of general data compression, such as the method of Lagrange multipliers, and thus they obtain sub‐optimal results, making it difficult to do a fair comparison of their performance.In this paper, we present a general preprocessing step based on Lagrange multipliers, which allows to rigorously adjust the precision in each of the degrees of freedom of the input data according to the amount of influence the given degree of freedom has on the overall distortion. We then present a simple compression method based on Principal Component Analysis, which in combination with the proposed preprocessing achieves significantly better results than current state of the art methods. It allows optimization with respect to various distortion metrics, and we discuss the choice of the metric in two common but distinct scenarios, proposing a perceptually oriented comparison metric based on the relation of the problem at hand to the problem of compression of dynamic meshes.
Pose partitioning for multi‐resolution segmentation of arbitrary mesh animations
Authors: A. Vasilakis Andreas , Fudos Ioannis 
Published: June 2014

AbstractWe present a complete approach to efficiently deriving a varying level‐of‐detail segmentation of arbitrary animated objects. An over‐segmentation is built by combining sets of initial segments computed for each input pose, followed by a fast progressive simplification which aims at preserving rigid segments. The final segmentation result can be efficiently adjusted for cases where pose editing is performed or new poses are added at arbitrary positions in the mesh animation sequence. A smooth view of pose‐to‐pose segmentation transitions is offered by merging the partitioning of the current pose with that of the next pose. A perceptually friendly visualization scheme is also introduced for propagating segment colors between consecutive poses. We report on the efficiency and quality of our framework as compared to previous methods under a variety of skeletal and highly deformable mesh animations.
Parameter estimation and comparative evaluation of crowd simulations
Authors: Wolinski D. , J. Guy S. , Olivier A.‐H. , Lin M. , Manocha D. , Pettré J. 
Published: June 2014

AbstractWe present a novel framework to evaluate multi‐agent crowd simulation algorithms based on real‐world observations of crowd movements. A key aspect of our approach is to enable fair comparisons by automatically estimating the parameters that enable the simulation algorithms to best fit the given data. We formulate parameter estimation as an optimization problem, and propose a general framework to solve the combinatorial optimization problem for all parameterized crowd simulation algorithms. Our framework supports a variety of metrics to compare reference data and simulation outputs. The reference data may correspond to recorded trajectories, macroscopic parameters, or artist‐driven sketches. We demonstrate the benefits of our framework for example‐based simulation, modeling of cultural variations, artist‐driven crowd animation, and relative comparison of some widely‐used multi‐agent simulation algorithms.
Flower reconstruction from a single photo
Authors: Yan Feilong , Gong Minglun , Cohen‐Or Daniel , Deussen Oliver , Chen Baoquan 
Published: June 2014

AbstractWe present a semi‐automatic method for reconstructing flower models from a single photograph. Such reconstruction is challenging since the 3D structure of a flower can appear ambiguous in projection. However, the flower head typically consists of petals embedded in 3D space that share similar shapes and form certain level of regular structure. Our technique employs these assumptions by first fitting a cone and subsequently a surface of revolution to the flower structure and then computing individual petal shapes from their projection in the photo. Flowers with multiple layers of petals are handled through processing different layers separately. Occlusions are dealt with both within and between petal layers. We show that our method allows users to quickly generate a variety of realistic 3D flowers from photographs and to animate an image using the underlying models reconstructed from our method.
Human bone chips release of sclerostin and FGF‐23 into the culture medium: an in vitro pilot study
Authors: Brolese Eliane , Buser Daniel , Kuchler Ulrike , Schaller Benoit , Gruber Reinhard 
Published: June 2014

AbstractObjectiveSignaling molecules derived from osteocytes have been proposed as a mechanism by which autografts contribute to bone regeneration. However, there have been no studies that determined the role of osteocytes in bone grafts.Material and methodHerein, it was examined whether bone chips and demineralized bone matrix release sclerostin and FGF‐23, both of which are highly expressed by osteocytes.ResultsBone grafts from seven donors were placed in culture medium. Immunoassay showed that bone chips released sclerostin (median 1.0 ng/ml) and FGF‐23 (median 9.8 relative units/ml) within the first day, with declining levels overtime. Demineralized bone matrix also released detectable amounts of sclerostin into culture medium, while FGF‐23 remained close to the detection limit. In vitro expanded isolated bone cells failed to release detectable amounts of sclerostin and FGF‐23.ConclusionThese results suggest that autografts but also demineralized bone matrix can release signaling molecules that are characteristically produced by osteocytes.
Bone remodeling at implants with different configurations and placed immediately at different depth into extraction sockets. Experimental study in dogs
Authors: Calvo‐Guirado José Luis , Gomez Moreno Gerardo , Aguilar‐Salvatierra Antonio , Mate Sanchez de Val Jose Eduardo , Abboud Marcus , Nemcovsky Carlos E. 
Published: June 2014

AbstractObjectivesThis study evaluated the effect of implant macrodesign and position, related to the bone crest, on bone‐to‐implant contact (BIC) and crestal bone (CB) in immediate implants.Material and methodsThe study comprised of six foxhound dogs in which 48 immediate implants were placed. Three types of implants from the same manufacturer with similar surface characteristics but different macrodesigns were randomly placed: Group A (external hex with no collar microthreads), Group B (internal hex and collar microrings), and Group C (internal conical connection and collar microrings). Half of the implants were placed leveled with the bone crest (control) and the remaining, 2 mm subcrestally (test). Block sections were obtained after 12 weeks and processed for mineralized ground sectioning. Statistical analysis consisted of nonparametric Friedman and Wilcoxon test.ResultsAll implants were clinically stable and histologically osseointegrated. Mean BIC percentage within the control group was as follows: A: 42.52 ± 8.67, B: 35.19 ± 18.12, and C: 47.46 ± 11.50. Within the test group: A: 47.33 ± 5.23, B: 48.38 ± 11.63, and C: 54.88 ± 11.73. Differences between each subgroup in the test and the control groups were statistically significant. BIC was statistically significantly higher in the test (50.588 ± 8.663) than in the control (43.317 ± 9.851) group. Within both groups, differences between group C and the other 2 were statistically significant. Distance from the implant shoulder to the buccal CB was statistically significantly larger in the control than in the test group and between subgroups B and C in the control and test groups. Within the test groups, relative bone gain was noticed.ConclusionsSubcrestal immediate implant positioning may lead to a relatively reduced CB resorption and increased BIC. Implants macrodesign with crestal microrings may enhance BIC in post‐extraction implants.
Anal intraepithelial neoplasia: a single centre 19 year review
Authors: Cotter M. B. , Kelly M. E. , O'Connell P. R. , Hyland J. , Winter D. C. , Sheahan K. , Gibbons D. 
Published: June 2014

AbstractAimThere is debate about whether the traditional three‐tiered grading of anal intraepithelial neoplasia (AIN) should be replaced by a more reproducible two‐tiered system. In this study, we review our experience with AIN to determine the most suitable classification system.MethodWe performed a retrospective review of all histological reports over a 19 year period. All specimens were graded on haemataloxin and eosin appearance and those with dysplasia had immunohistochemistry for p16 and Ki67 performed.ResultsCases included 25 condyloma acuminata, 11 dysplastic cases and 24 invasive squamous cell carcinomas. On review, 18 were classified as condyloma acuminata without dysplasia. Seven had AIN I, five had AIN II and six had AIN III when using a three‐tiered system. All cases classified as dysplastic (n = 18) showed an increased proliferation index as measured by Ki67. p16 positivity was seen in all AIN III, two AIN II and none of the AIN I cases. Recurrence was not observed in any of the AIN I cases. Five of eleven AIN II and AIN III cases recurred or persisted at a similar, higher or lower grade. Both of the AIN II cases which recurred or persisted were p16 positive. None of the AIN II cases that were p16 negative recurred. Three of the p16‐positive AIN III cases did not recur. None of the 18 AIN cases progressed to carcinoma.ConclusionThe findings support the slow progression of AIN as described in the literature. In our small series, a two‐tiered system with further subclassification of the traditional AIN II group using p16 appears to be clinically useful.
Action Attenuates the Effect of Visibility on Gesture Rates
Authors: Hostetter Autumn B. 
Published: June 2014

AbstractMuch evidence suggests that semantic characteristics of a message (e.g., the extent to which the message evokes thoughts of spatial or motor properties) and social characteristics of a speaking situation (e.g., whether there is a listener who can see the speaker) both influence how much speakers gesture. However, the Gesture as Simulated Action (GSA) framework (Hostetter & Alibali, ) predicts that these effects should not be independent but should interact such that the effect of visibility is lessened when a message evokes strong thoughts of action. This study tested this claim by comparing the gesture rates produced by speakers as they described 24 nouns that vary in how strongly they evoke thoughts of action. Further, half of the words were described with visibility between speaker and listener blocked. The results demonstrated a significant interaction as predicted by the GSA framework.
Network‐based identification of key proteins involved in apoptosis and cell cycle regulation
Authors: Wu L. , Zhou N. , Sun R. , Chen X. D. , Feng S. C. , Zhang B. , Bao J. K. 
Published: June 2014

AbstractObjectivesCancer cells differ from normal body cells in their ability to divide indefinitely and to evade programmed cell death. Crosstalk between apoptosis and cell cycle processes promotes balance between proliferation and death, and limits population growth and survival of cells. However, intricate relationships between them and how they are able to manipulate the fate of cancer cells still remain to be clarified. Identification of key factors involved in both apoptosis and cell cycle regulation may help to address this problem.Materials and methodsIdentification of such key proteins was carried out, using a series of bioinformatics methods, such as network construction and key protein identification.ResultsIn this study, we computationally constructed human apoptotic/cell cycle‐related protein‐protein interactions (PPIs) networks from five experimentally supported protein interaction databases, and further integrated these high‐throughput data sets into a Naïve Bayesian model to predict protein functional connections. On the basis of modified apoptotic/cell cycle related PPI networks, we calculated and ranked all protein members involved in apoptosis and cell cycle regulation. Our results not only identified some already known key proteins such as p53, Rb, Myc and Src but also found that the proteasome, Cullin family members, kinases and transcriptional repressors play important roles in regulating apoptosis and the cell cycle. Furthermore, we found that the top 100 proteins ranked by PeC were enriched in some pathways such as those of cancer, the proteasome, the cell cycle and Wnt signalling.ConclusionsWe constructed the global human apoptotic/cell cycle related PPI network based on five online databases, and a Naïve Bayesian model. In addition, we systematically identified apoptotic/cell cycle related key proteins in cancer cells. These findings may uncover intricate relationships between apoptosis and cell cycle processes and thus provide further new clues towards future anticancer drug discovery.
Beaver dams shift desert fish assemblages toward dominance by non‐native species (Verde River, Arizona, USA)
Authors: Gibson Polly P. , Olden Julian D. , O'Neill Matthew W. 
Published: June 2014

AbstractThe reintroduction of beaver (Castor canadensis) into arid and semi‐arid rivers is receiving increasing management and conservation attention in recent years, yet very little is known about native versus non‐native fish occupancy in beaver pond habitats. Streams of the American Southwest support a highly endemic, highly endangered native fish fauna and abundant non‐native fishes, and here we investigated the hypothesis that beaver ponds in this region may lead to fish assemblages dominated by non‐native species that favour slower‐water habitat. We sampled fish assemblages within beaver ponds and within unimpounded lotic stream reaches in the mainstem and in tributaries of the free‐flowing upper Verde River, Arizona, USA. Non‐native fishes consistently outnumbered native species, and this dominance was greater in pond than in lotic assemblages. Few native species were recorded within ponds. Multivariate analysis indicated that fish assemblages in beaver ponds were distinct from those in lotic reaches, in both mainstem and tributary locations. Individual species driving this distinction included abundant non‐native green sunfish (Lepomis cyanellus) and western mosquitofish (Gambusia affinis) in pond sites, and native desert sucker (Catostomus clarkii) in lotic sites. Overall, this study provides the first evidence that, relative to unimpounded lotic habitat, beaver ponds in arid and semi‐arid rivers support abundant non‐native fishes; these ponds could thus serve as important non‐native source areas and negatively impact co‐occurring native fish populations.
Regional analysis of striatal and cortical amyloid deposition in patients with Alzheimer's disease
Authors: Ishibashi Kenji , Ishiwata Kiichi , Toyohara Jun , Murayama Shigeo , Ishii Kenji 
Published: June 2014

AbstractWe aimed to analyse the detailed distribution pattern of amyloid‐β (Aβ) in the striatum, and to examine whether there is any correlation between Aβ deposition levels in the striatum and cortical regions. Twenty patients with Alzheimer's disease underwent positron emission tomography using 11C‐Pittsburgh Compound B (11C‐PiB) to quantify the Aβ deposition. Volumes‐of‐interest analyses were performed on the ventral striatum (VST), pre‐commissural dorsal caudate (pre‐DCA), post‐commissural caudate (post‐CA), pre‐commissural dorsal putamen (pre‐DPU), and post‐commissural putamen (post‐PU), followed by exploratory voxel‐wise analyses. Volumes‐of‐interest analyses of 11C‐PiB binding showed: VST > pre‐DPU (P = 0.004), VST > pre‐DCA (P < 0.0001), pre‐DPU > post‐PU (P < 0.0001), and pre‐DCA > post‐CA (P < 0.0001), consistent with visual inspection of the 11C‐PiB images. Exploratory voxel‐wise analyses of 11C‐PiB binding showed a positive correlation between the VST and the medial part of the orbitofrontal area (P < 0.01 family‐wise error corrected). This study confirmed that there were ventral > dorsal, and anterior > posterior gradients of Aβ deposition in patients with Alzheimer's disease, and provided the first evidence of a robust correlation between Aβ deposition levels in the VST and the medial part of the orbitofrontal area. There are well‐known anatomical and functional links between these areas. These findings indicated that brain Aβ deposition was not randomly distributed, but had characteristic patterns related to anatomical connectivity and/or functional networks.