8,903 research outputs found
Using Stacked Sparse Auto-Encoder and Superpixel CRF for Long-Term Visual Scene Understanding of UGVs
Multiple images have been widely used for scene understanding and navigation of unmanned ground vehicles in long term operations. However, as the amount of visual data in multiple images is huge, the cumulative error in many cases becomes untenable. This paper proposes a novel method that can extract features from a large dataset of multiple images efficiently. Then the membership K-means clustering is used for high dimensional features, and the large dataset is divided into N subdatasets to train N conditional random field (CRF) models based on superpixel. A Softmax subdataset selector is used to decide which one of the N CRF models is chosen as the prediction model for labeling images. Furthermore, some experiments are conducted to evaluate the feasibility and performance of the proposed approach
Reaction mechanism analysis of the Al2O3 in blast furnace (BF) slag
Al2O3 is one of the main component in blast furnace (BF) slag, which the reaction mechanism influence on the metallurgical performance directly in the process of the slag forming. In the paper, ΔGfθ was used to analyzed the slag formation reaction process of the Al2O3, at the same time, the phase diagram and activity were calculated by Fact-Sage with CaO - MgO – SiO2 - Al2O3 slag system, it can be found that the complete liquid phase region temperature is about 1 500°C and the content of the Al2O3 is 11%. Activity of CaO is stronger than the others, from which the liquid phase can be formed easily in the high temperature, meantime the reaction energy barrier between CaO and SiO2 is lower and stabilization of the product is better. By the high temperature experiment, a lot of Ca2Al2SiO7 was separated out with the high content of Al2O3 and slag basicity, as a result, the transformation of the solid phase to the liquid phase was effected by the constantly increasing the content of Al2O3
Ultrathin MgB2 films fabricated on Al2O3 substrate by hybrid physical-chemical vapor deposition with high Tc and Jc
Ultrathin MgB2 superconducting films with a thickness down to 7.5 nm are
epitaxially grown on (0001) Al2O3 substrate by hybrid physical-chemical vapor
deposition method. The films are phase-pure, oxidation-free and continuous. The
7.5 nm thin film shows a Tc(0) of 34 K, which is so far the highest Tc(0)
reported in MgB2 with the same thickness. The critical current density of
ultrathin MgB2 films below 10 nm is demonstrated for the first time as Jc ~
10^6 A cm^{-2} for the above 7.5 nm sample at 16 K. Our results reveal the
excellent superconducting properties of ultrathin MgB2 films with thicknesses
between 7.5 and 40 nm on Al2O3 substrate.Comment: 7 pages, 4 figures, 2 table
Acute infection of chinese macaques by a CCR5-tropic SHIV carrying a primary HIV-1 subtype B' envelope
The increasing prevalence of HIV-1 subtype B' in China and Southeast Asia calls for efforts to develop a relevant animal model to study viral transmission and pathogenesis. Because there are significant differences between subtype B' HIV-1 and other chimeric simian/human immunodeficiency viru (SHIVs) in the env gene, a novel SHIV, designated SHIV B'WHU, was generated by replacing counterparts of SHIVSF33 with tat/rev/vpu/env genes derived from a primary, CCR5-tropic, subtype B' HIV-1 strain of a Chinese patient. SHIV B'WHU was able to replicate in rhesus peripheral blood mononuclear cells and used CCR5 as its major coreceptor. Moreover, after serial passages in Chinese macaques, the in vivo infectivity of SHIV B' WHU was enhanced, yet no significant sequence changes were found in viral envelopes, and the virus did not change its CCR5-tropism. CD4 T-cell loss, however, was found in the intraepithelial lymphocytes of small intestines of infected macaques. Our findings have implications in understanding the early pathogenesis of SHIV B' WHU in Chinese macaques. Copyright © 2010 by Lippincott Williams & Wilkins.postprin
Pericytes promote skin regeneration by inducing epidermal cell polarity and planar cell divisions.
The cellular and molecular microenvironment of epithelial stem/progenitor cells is critical for their long-term self-renewal. We demonstrate that mesenchymal stem cell-like dermal microvascular pericytes are a critical element of the skin's microenvironment influencing human skin regeneration using organotypic models. Specifically, pericytes were capable of promoting homeostatic skin tissue renewal by conferring more planar cell divisions generating two basal cells within the proliferative compartment of the human epidermis, while ensuring complete maturation of the tissue both spatially and temporally. Moreover, we provide evidence supporting the notion that BMP-2, a secreted protein preferentially expressed by pericytes in human skin, confers cell polarity and planar divisions on epidermal cells in organotypic cultures. Our data suggest that human skin regeneration is regulated by highly conserved mechanisms at play in other rapidly renewing tissues such as the bone marrow and in lower organisms such as Drosophila. Our work also provides the means to significantly improve ex vivo skin tissue regeneration for autologous transplantation
Entanglement-Assisted Communication Surpassing the Ultimate Classical Capacity
Entanglement underpins a variety of quantum-enhanced communication, sensing,
and computing capabilities. Entanglement-assisted communication (EACOMM)
leverages entanglement pre-shared by communication parties to boost the rate of
classical information transmission. Pioneering theory works showed that EACOMM
can enable a communication rate well beyond the ultimate classical capacity of
optical communications, but an experimental demonstration of any EACOMM
advantage remains elusive. Here, we report the implementation of EACOMM
surpassing the classical capacity over lossy and noisy bosonic channels. We
construct a high-efficiency entanglement source and a phase-conjugate quantum
receiver to reap the benefit of pre-shared entanglement, despite entanglement
being broken by channel loss and noise. We show that EACOMM beats the
Holevo-Schumacher-Westmoreland capacity of classical communication by up to
14.6%, when both protocols are subject to the same power constraint at the
transmitter. As a practical performance benchmark, a classical communication
protocol without entanglement assistance is implemented, showing that EACOMM
can reduce the bit-error rate by up to 69% over the same bosonic channel. Our
work opens a route to provable quantum advantages in a wide range of quantum
information processing tasks.Comment: 12 pages, 5 figures. Comments are welcom
A Bayesian graph embedding model for link-based classification problems
In recent years, the analysis of human interaction data has led to the rapid development of graph embedding methods. For link-based classification problems, topological information typically appears in various machine learning tasks in the form of embedded vectors or convolution kernels. This paper introduces a Bayesian graph embedding model for such problems, integrating network reconstruction, link prediction, and behavior prediction into a unified framework. Unlike the existing graph embedding methods, this model does not embed the topology of nodes or links into a low-dimensional space but sorts the probabilities of upcoming links and fuses the information of node topology and data domain via sorting. The new model integrates supervised transaction predictors with unsupervised link prediction models, summarizing local and global topological information. The experimental results on a financial trading dataset and a retweet network dataset demonstrate that the proposed feature fusion model outperforms the tested benchmarked machine learning algorithms in precision, recall, and F1-measure. The proposed learning structure has a fundamental methodological contribution and can be extended and applied to various link-based classification problems in different fields
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