124 research outputs found

    Efficient Graduated Non-Convexity for Pose Graph Optimization

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    We propose a novel approach to Graduated Non-Convexity (GNC) and demonstrate its efficacy through its application in robust pose graph optimization, a key component in SLAM backends. Traditional GNC methods often rely on heuristic methods for GNC schedule, updating control parameter {\mu} for escalating the non-convexity. In contrast, our approach leverages the properties of convex functions and convex optimization to identify the boundary points beyond which convexity is no longer guaranteed, thereby eliminating redundant optimization steps in existing methodologies and enhancing both speed and robustness. We show that our method outperforms the state-of-the-art method in terms of speed and accuracy when used for robust back-end pose graph optimization via GNC. Our work builds upon and enhances the open-source riSAM framework. Our implementation can be accessed from: https://github.com/SNU-DLLAB/EGNC-PGOComment: 6 pages, 6 figure

    Adaptive Graduated Non-Convexity for Pose Graph Optimization

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    We present a novel approach to robust pose graph optimization based on Graduated Non-Convexity (GNC). Unlike traditional GNC-based methods, the proposed approach employs an adaptive shape function using B-spline to optimize the shape of the robust kernel. This aims to reduce GNC iterations, boosting computational speed without compromising accuracy. When integrated with the open-source riSAM algorithm, the method demonstrates enhanced efficiency across diverse datasets. Accompanying open-source code aims to encourage further research in this area. https://github.com/SNU-DLLAB/AGNC-PGOComment: 4 pages, 3 figures. Accepted for the workshop on Robotic Perception and Mapping(ROPEM): Frontier Vision & Learning Techniques, organized at the 2023 International Conference on Intelligent Robots and Systems (IROS

    CLARA: Classifying and Disambiguating User Commands for Reliable Interactive Robotic Agents

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    In this paper, we focus on inferring whether the given user command is clear, ambiguous, or infeasible in the context of interactive robotic agents utilizing large language models (LLMs). To tackle this problem, we first present an uncertainty estimation method for LLMs to classify whether the command is certain (i.e., clear) or not (i.e., ambiguous or infeasible). Once the command is classified as uncertain, we further distinguish it between ambiguous or infeasible commands leveraging LLMs with situational aware context in a zero-shot manner. For ambiguous commands, we disambiguate the command by interacting with users via question generation with LLMs. We believe that proper recognition of the given commands could lead to a decrease in malfunction and undesired actions of the robot, enhancing the reliability of interactive robot agents. We present a dataset for robotic situational awareness, consisting pair of high-level commands, scene descriptions, and labels of command type (i.e., clear, ambiguous, or infeasible). We validate the proposed method on the collected dataset, pick-and-place tabletop simulation. Finally, we demonstrate the proposed approach in real-world human-robot interaction experiments, i.e., handover scenarios

    Targeting Myocardial Equilibrative Nucleoside Transporter ENT1 Provides Cardioprotection by Enhancing Myeloid Adora2b Signaling.

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    Previous studies implicate extracellular adenosine signaling in attenuating myocardial ischemia and reperfusion injury (IRI). This extracellular adenosine signaling is terminated by its uptake into cells by equilibrative nucleoside transporters (ENTs). Thus, we hypothesized that targeting ENTs would function to increase cardiac adenosine signaling and concomitant cardioprotection against IRI. Mice were exposed to myocardial ischemia and reperfusion injury. Myocardial injury was attenuated in mice treated with the nonspecific ENT inhibitor dipyridamole. A comparison of mice with global Ent1 or Ent2 deletion showed cardioprotection only in Ent1-/- mice. Moreover, studies with tissue-specific Ent deletion revealed that mice with myocyte-specific Ent1 deletion (Ent1loxP/loxP Myosin Cre+ mice) experienced smaller infarct sizes. Measurements of cardiac adenosine levels demonstrated that postischemic elevations of adenosine persisted during reperfusion after targeting ENTs. Finally, studies in mice with global or myeloid-specific deletion of the Adora2b adenosine receptor (Adora2bloxP/loxP LysM Cre+ mice) implied that Adora2b signaling on myeloid-inflammatory cells in cardioprotection provided by ENT inhibition. These studies reveal a previously unrecognized role for myocyte-specific ENT1 in cardioprotection by enhancing myeloid-dependent Adora2b signaling during reperfusion. Extension of these findings implicates adenosine transporter inhibitors in cardioprotection against ischemia and reperfusion injury

    The Sedimentary records of the Hapcheon impact crater basin in Korea over the past 1.3 Ma

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    The Hapcheon impact crater is the only meteorite impact crater identified on the Korean peninsula. However, the morphology of the impact crater and the nature of the meteorite collision are unknown. In this study, we analyzed the sedimentary facies using grain size data; computed tomography images, 14C, 10Be, and optically stimulated luminescence dating on a >66-m-long sediment core (20HCL04) recovered from the Hapcheon Basin. Four sedimentary units and 10 types of facies were documented in the Hapcheon Basin sediment core. The sedimentary units comprise 1) a lower part (unit 1) that is dominated by moderately to well-sorted coarse gravel, which contains some impact-related sediments; 2) a middle part (units 2 and 3) dominated by well-laminated mud; and 3) an upper part (Unit 4) that is dominated by poorly sorted coarse gravel supplied from the surrounding mountain slopes by alluvial and fluvial processes. After the meteorite impact, the Hapcheon impact crater was filled with deposits from the crater wall after ca. 1.3 Ma and the Hapcheon Basin became a deep lake environment. After ca. 0.5 Ma, sediments were supplied from the surrounding mountains until the lake was filled. Finally, sediments were deposited in an alluvial fan setting. In addition, the Hapcheon Basin sedimentary cores contain a tephra layer and deformed soft sediments that can be used to investigate volcanic and seismic events on the Korean Peninsula over the past 1.3 Ma

    Two-loop Barr-Zee type Contributions to (g2)μ(g-2)_\mu in the MSSM

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    We consider the contribution of a two-loop Barr-Zee type diagram to (g2)μ(g-2)_\mu in the minimal supersymmetric standard model (MSSM). At relatively large tanβ\tan\beta, we show that the contribution of light third generation scalar fermions and neutral CP-even Higgs, h0(H0)h^0(H^0), can easily explain the very recent BNL experimental data. In our analysis (g2)μ(g-2)_\mu prefers negative AfA_{f} and positive μ\mu. It is more sensitive to the chirality flipping h^0(H^0)\wt{f}_R^*\wt{f}_L rather than chirality conserving couplings.Comment: 10 pages, 5 figures, references adde
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