97 research outputs found
Thermal behavior of elastic columns with second-mode imperfections
Pin-ended columns having an initial imperfection in a second buckling mode and subjected to thermal loading have been studied in this paper. Based on a nonlinear relationship between strains and displacements, the buckling equilibrium equations are given with the energy method. Then the formulae for the axial compression and transversal displacement are presented. The relationship between the anti-symmetric imperfection and the axial compression has been studied along with the effect of elevated temperature on the initial imperfection. The response of the column in fire to the modified slenderness ratio is investigated. The proposed method has the potential to provide more detailed information for column designs and thus be deployed in future research to minimize the need for expensive laboratory testing
DeepSketch2Face: A Deep Learning Based Sketching System for 3D Face and Caricature Modeling
Face modeling has been paid much attention in the field of visual computing.
There exist many scenarios, including cartoon characters, avatars for social
media, 3D face caricatures as well as face-related art and design, where
low-cost interactive face modeling is a popular approach especially among
amateur users. In this paper, we propose a deep learning based sketching system
for 3D face and caricature modeling. This system has a labor-efficient
sketching interface, that allows the user to draw freehand imprecise yet
expressive 2D lines representing the contours of facial features. A novel CNN
based deep regression network is designed for inferring 3D face models from 2D
sketches. Our network fuses both CNN and shape based features of the input
sketch, and has two independent branches of fully connected layers generating
independent subsets of coefficients for a bilinear face representation. Our
system also supports gesture based interactions for users to further manipulate
initial face models. Both user studies and numerical results indicate that our
sketching system can help users create face models quickly and effectively. A
significantly expanded face database with diverse identities, expressions and
levels of exaggeration is constructed to promote further research and
evaluation of face modeling techniques.Comment: 12 pages, 16 figures, to appear in SIGGRAPH 201
Application of a Microstructure-Based ISV Plasticity Damage Model to Study Penetration Mechanics of Metals and Validation through Penetration Study of Aluminum
A developed microstructure-based internal state variable (ISV) plasticity damage model is for the first time used for simulating penetration mechanics of aluminum to find out its penetration properties. The ISV damage model tries to explain the interplay between physics at different length scales that governs the failure and damage mechanisms of materials by linking the macroscopic failure and damage behavior of the materials with their micromechanical performance, such as void nucleation, growth, and coalescence. Within the continuum modeling framework, microstructural features of materials are represented using a set of ISVs, and rate equations are employed to depict damage history and evolution of the materials. For experimental calibration of this damage model, compression, tension, and torsion straining conditions are considered to distinguish damage evolutions under different stress states. To demonstrate the reliability of the presented ISV model, that model is applied for studying penetration mechanics of aluminum and the numerical results are validated by comparing with simulation results yielded from the Johnson-Cook model as well as analytical results calculated from an existing theoretical model
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Oxysterol binding to the extracellular domain of Smoothened in Hedgehog signaling
Oxysterols bind the seven-spanner transmembrane protein Smoothened and potently activate vertebrate Hedgehog signaling, a pathway essential in embryonic development, adult stem cell maintenance and cancer. It is unknown, however, if oxysterols are important for normal vertebrate Hedgehog signaling, and whether antagonizing oxysterols can inhibit the Hedgehog pathway. We developed azasterols that block Hedgehog signaling by binding the oxysterol-binding site of Smoothened. We show that the binding site for oxysterols and azasterols maps to the extracellular, cysteine-rich domain of Smoothened, and is completely separable from the site bound by other small molecule modulators, located within the heptahelical bundle of Smoothened. Smoothened mutants in which oxysterol binding is abolished no longer respond to oxysterols, and cannot be maximally activated by the Hedgehog ligand. Our results show that oxysterol binding to vertebrate Smoothened is required for normal Hedgehog signaling, and that targeting the oxysterol binding site is an effective strategy to inhibit Smoothened
Going Deeper with Convolutions
We propose a deep convolutional neural network architecture codenamed
"Inception", which was responsible for setting the new state of the art for
classification and detection in the ImageNet Large-Scale Visual Recognition
Challenge 2014 (ILSVRC 2014). The main hallmark of this architecture is the
improved utilization of the computing resources inside the network. This was
achieved by a carefully crafted design that allows for increasing the depth and
width of the network while keeping the computational budget constant. To
optimize quality, the architectural decisions were based on the Hebbian
principle and the intuition of multi-scale processing. One particular
incarnation used in our submission for ILSVRC 2014 is called GoogLeNet, a 22
layers deep network, the quality of which is assessed in the context of
classification and detection
Optimized Broadcast for Deep Learning Workloads on Dense-GPU InfiniBand Clusters: MPI or NCCL?
Dense Multi-GPU systems have recently gained a lot of attention in the HPC
arena. Traditionally, MPI runtimes have been primarily designed for clusters
with a large number of nodes. However, with the advent of MPI+CUDA applications
and CUDA-Aware MPI runtimes like MVAPICH2 and OpenMPI, it has become important
to address efficient communication schemes for such dense Multi-GPU nodes. This
coupled with new application workloads brought forward by Deep Learning
frameworks like Caffe and Microsoft CNTK pose additional design constraints due
to very large message communication of GPU buffers during the training phase.
In this context, special-purpose libraries like NVIDIA NCCL have been proposed
for GPU-based collective communication on dense GPU systems. In this paper, we
propose a pipelined chain (ring) design for the MPI_Bcast collective operation
along with an enhanced collective tuning framework in MVAPICH2-GDR that enables
efficient intra-/inter-node multi-GPU communication. We present an in-depth
performance landscape for the proposed MPI_Bcast schemes along with a
comparative analysis of NVIDIA NCCL Broadcast and NCCL-based MPI_Bcast. The
proposed designs for MVAPICH2-GDR enable up to 14X and 16.6X improvement,
compared to NCCL-based solutions, for intra- and inter-node broadcast latency,
respectively. In addition, the proposed designs provide up to 7% improvement
over NCCL-based solutions for data parallel training of the VGG network on 128
GPUs using Microsoft CNTK.Comment: 8 pages, 3 figure
Cervical HPV infection in Yueyang, China: a cross-sectional study of 125,604 women from 2019 to 2022
ObjectiveHuman papillomavirus (HPV) infection is currently the main cause of cervical cancer and precancerous lesions in women. The aim of this study was to investigate the epidemiological characteristics of HPV genotypes among women in Yueyang city and to provide a basis for the prevention and treatment of cervical cancer in this city.MethodsA cross-sectional study was conducted on 125,604 women who had received treatment from eight hospitals in Yueyang city from September 2019 to September 2022. Analysis of the prevalence of HPV in patients.ResultsThe prevalence of HPV was 20.5% (95%CI: 20.2–20.7%), of which the high-risk type (HR-HPV) accounted for 17.5% (95%CI: 17.3–17.7%) and the low-risk type (LR-HPV) accounted for 5.0% (95%CI: 4.9–5.1%). Among the HR-HPV subtypes, the top five in prevalence, from the highest to the lowest, were HPV52 (5.1%), HPV16(2.7%), HPV58 (2.6%), HPV53 (2.4%), and HPV51 (1.7%). The main LR-HPV infection types were HPV81 (2,676 cases, OR = 2.1%; 95%CI, 2.0–2.1%). Among the infected patients, 19,203 cases (OR = 74.3%; 95%CI, 73.8–74.9%) had a single subtype, 4,673 cases (OR = 18.1%; 95%CI, 17.6–18.6%) had two subtypes, and 1957 cases (OR = 7.6%; 95%CI, 7.3–7.9%) had three or more subtypes. HPV prevalence is highest among women <25 years, 55–64 years and ≥ 65 years of age.ConclusionThe prevalence of HPV in women in Yueyang city was 20.5%, with HR-HPV being dominant. As women aged <25 years, 55–64 years, and ≥ 65 years are at a relatively higher risk, more attention should be paid to them for prevention and control of HPV infections
The gut microbiome in atherosclerotic cardiovascular disease
The gut microbiota may play a role in cardiovascular diseases. Here, the authors perform a metagenome-wide association study on stools from individuals with atherosclerotic cardiovascular disease and healthy controls, identifying microbial strains and functions associated with the disease
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