255 research outputs found

    Visual SLAM algorithms: a survey from 2010 to 2016

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    SLAM is an abbreviation for simultaneous localization and mapping, which is a technique for estimating sensor motion and reconstructing structure in an unknown environment. Especially, Simultaneous Localization and Mapping (SLAM) using cameras is referred to as visual SLAM (vSLAM) because it is based on visual information only. vSLAM can be used as a fundamental technology for various types of applications and has been discussed in the field of computer vision, augmented reality, and robotics in the literature. This paper aims to categorize and summarize recent vSLAM algorithms proposed in different research communities from both technical and historical points of views. Especially, we focus on vSLAM algorithms proposed mainly from 2010 to 2016 because major advance occurred in that period. The technical categories are summarized as follows: feature-based, direct, and RGB-D camera-based approaches

    Production of overdense plasmas by launching 2,45 GHz electron cyclotron waves in a helical device

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    For production of low temperature plasmas with low collisionality, 2.45GHz microwave power up to 20kW is injected perpendicularly to the toroidal field at very low toroidal field BtComment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

    Augmenting NER Datasets with LLMs: Towards Automated and Refined Annotation

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    In the field of Natural Language Processing (NLP), Named Entity Recognition (NER) is recognized as a critical technology, employed across a wide array of applications. Traditional methodologies for annotating datasets for NER models are challenged by high costs and variations in dataset quality. This research introduces a novel hybrid annotation approach that synergizes human effort with the capabilities of Large Language Models (LLMs). This approach not only aims to ameliorate the noise inherent in manual annotations, such as omissions, thereby enhancing the performance of NER models, but also achieves this in a cost-effective manner. Additionally, by employing a label mixing strategy, it addresses the issue of class imbalance encountered in LLM-based annotations. Through an analysis across multiple datasets, this method has been consistently shown to provide superior performance compared to traditional annotation methods, even under constrained budget conditions. This study illuminates the potential of leveraging LLMs to improve dataset quality, introduces a novel technique to mitigate class imbalances, and demonstrates the feasibility of achieving high-performance NER in a cost-effective way

    Impaired response of hypoxic sensor protein HIF-1 alpha and its downstream proteins in the spinal motor neurons of ALS model mice

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    We have recently reported spinal blood flow-metabolism uncoupling in an amyotrophic lateral sclerosis (ALS) animal model using Cu/Zn-superoxide dismutase 1 (SOD1)-transgenic (Tg) mice, suggesting a relative hypoxia in the spinal cord. However, the hypoxic stress sensor pathway has not been well studied in ALS. Here, we examined temporal and spatial changes of the hypoxic stress sensor proteins HIF-1 alpha and its downstream proteins (VEGF, HO-1, and EPO) during the normcodccourse of motor neuron (MN) degeneration in the spinal cord of these ALS model mice. We found that HIP-1 alpha protein expression progressively increased both in the anterior large MNs and the surrounding glial cells in Tg mice from early symptomatic 14 week (W) and end stage 18W. Double immunofluorescence analysis revealed that HIP-1 alpha, plus GFAP and Iba-1 double-positive surrounding glial cells, progressively increased from 14 W to 18 W, although the immunohistochemistiy in large MNs did not change. Expression levels of VEGF and HO-1 also showed a progressive increase but were significant only in the surrounding glial cells at 18W. In contrast, EPO protein expression was decreased in the surrounding glial cells of Tg mice at 18W. Because HIF1-alpha serves as an important mediator of the hypoxic response, these findings indicate that MNs lack the neuroprotective response to hypoxic stress through the HIF-1 alpha system, which could be an important mechanism of neurodegeneration in ALS

    Experimental Simulation of High Temperature Plasma Transport Using Almost Dimensionally Similar Cold Plasmas in the Compact Helical System

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    In the Compact Helical System (CHS), experimental simulation of high temperature plasma transport is attempted by using cold plasma having similar dimensionless parameters such as electron-ion collision frequency normalized by bounce frequency v*ei, averaged toroidal beta value βt and the normalized gyro radius ρs*. The cold plasma is produced by 2.45 GHz electron cyclotron waves at very low toroidal field less than 0.1 T, and has v*ei ~ 0.05?1, βt < 0.02 % and ρs* ~ 0.02?0.05. The radial profiles of fluctuation amplitude have similarity to those in a high temperature plasma. In the cold plasma with low v*ei < 0.1, internal transport barrier is clearly formed in electron density and temperature profiles when the radial electric field rapidly evolves to positive value
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