2,110 research outputs found

    A Distributed Reconfigurable Control Law for Escorting and Patrolling Missions using Teams of Unicycles

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    A Distributed Reconfigurable Control Law for Escorting and Patrolling Missions using Teams of Unicycles

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    OmniZoomer: Learning to Move and Zoom in on Sphere at High-Resolution

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    Omnidirectional images (ODIs) have become increasingly popular, as their large field-of-view (FoV) can offer viewers the chance to freely choose the view directions in immersive environments such as virtual reality. The M\"obius transformation is typically employed to further provide the opportunity for movement and zoom on ODIs, but applying it to the image level often results in blurry effect and aliasing problem. In this paper, we propose a novel deep learning-based approach, called \textbf{OmniZoomer}, to incorporate the M\"obius transformation into the network for movement and zoom on ODIs. By learning various transformed feature maps under different conditions, the network is enhanced to handle the increasing edge curvatures, which alleviates the blurry effect. Moreover, to address the aliasing problem, we propose two key components. Firstly, to compensate for the lack of pixels for describing curves, we enhance the feature maps in the high-resolution (HR) space and calculate the transformed index map with a spatial index generation module. Secondly, considering that ODIs are inherently represented in the spherical space, we propose a spherical resampling module that combines the index map and HR feature maps to transform the feature maps for better spherical correlation. The transformed feature maps are decoded to output a zoomed ODI. Experiments show that our method can produce HR and high-quality ODIs with the flexibility to move and zoom in to the object of interest. Project page is available at http://vlislab22.github.io/OmniZoomer/.Comment: Accepted by ICCV 202

    Rho GTPase Signaling Activates Microtubule Severing to Promote Microtubule Ordering in Arabidopsis

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    SummaryBackgroundOrdered cortical microtubule (MT) arrays play a critical role in the spatial control of cell division and expansion and are essential for plant growth, morphogenesis, and development. Various developmental, hormonal, and mechanical signals and a large number of MT-associated proteins are known to impact cortical MT organization, but the underlying mechanisms remain poorly understood. Our previous studies show that auxin signaling, which is mediated by the ROP6 Rho GTPase and its effector RIC1, promotes the ordering of cortical MTs in pavement cells, but it is unknown how RIC1 controls the organization of cortical MTs into well-ordered arrays.ResultsOur genetic screens identified the conserved MT-severing protein katanin (KTN1) as a downstream component of the ROP6-RIC1 signaling pathway leading to well-ordered arrangement of cortical MTs. KTN1 and RIC1 proteins displayed overlapping localization. InĀ vivo and inĀ vitro studies showed that RIC1 physically interacts with and promotes the MT-severing activity of KTN1. Live-cell imaging reveals a role for RIC1 in promoting detachment of branched MTs that is known to rely on KTN1.ConclusionWe have demonstrated that a Rho GTPase signaling pathway regulates katanin-mediated MT severing in plant cells and uncovered an explicit regulatory mechanism underpinning the alignment and ordering of cortical MTs inĀ plants. Our findings provide new insights into regulatory mechanisms underlying growth stimuli such as auxin promote the organization of cortical MTs into parallel arrays in plants

    Topological Atomic Spinwave Lattices by Dissipative Couplings

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    Recent experimental advance in creating dissipative couplings provides a new route for engineering exotic lattice systems and exploring topological dissipation. Using the spatial lattice of atomic spinwaves in a vacuum vapor cell, where purely dissipative couplings arise from diffusion of atoms, we experimentally realize a dissipative version of the Su-Schrieffer-Heeger (SSH) model. We construct the dissipation spectra of the topological or trivial lattices via electromagnetically-induced-transparency (EIT) spectroscopy. The topological dissipation spectrum is found to exhibit edge modes at dissipation rates within a dissipative gap, decoupled from the bulk. We also validate chiral symmetry of the dissipative SSH couplings. This work paves the way for realizing topology-enabled quantum correlations and non-Hermitian topological quantum optics via dissipative couplings.Comment: 5 pages, 4 figure

    Effects of force load, muscle fatigue and magnetic stimulation on surface electromyography during side arm lateral raise task: a preliminary study with healthy subjects

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    The aim of this study was to quantitatively investigate the effects of force load, muscle fatigue and extremely low frequency (ELF) magnetic stimulation on surface electromyography (SEMG) signal features during side arm lateral raise task. SEMG signals were recorded from 18 healthy subjects on the anterior deltoid using a BIOSEMI Active Two system during side lateral raise task (with the right arm 90 degrees away from the body) with three different loads on the forearm (0kg, 1kg and 3 kg; their order was randomized between subjects). The arm maintained the loads until the subject felt exhausted. The first 10s recording for each load was regarded as non-fatigue status and the last 10s before the subject was exhausted as fatigue status. The subject was then given a five-minute resting between different loads. Two days later, the same experiment was repeated on every subject, while this time the ELF magnetic stimulation was applied to the subjectā€™s deltoid muscle during the five-minute rest period. Three commonly used SEMG features, including root mean square (RMS), median frequency (MDF) and sample entropy (SampEn) were analyzed and compared between different loads, non-fatigue/fatigue status, and with/without ELF magnetic stimulation. Variance analysis results showed that the effect of force load on RMS was significant (p0.05). In comparison with non-fatigue status, for all the different force loads with and without ELF stimulation, RMS was significantly larger at fatigue (all p0.05). Finally, the RMS, MDF, SampEn and their changes with force were not significantly different between with and without ELF stimulation (all p>0.05). Our study comprehensively quantified the effects of force, fatigue and the ELF magnetic stimulation on SEMG features, which may facilitate a better understanding of the underlying physiological mechanisms of muscle activities associated with force and fatigue, and of muscle physiological response to ELF magnetic stimulation

    A distributed reconfigurable control law for escorting and patrolling missions using teams of unicycles

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    Abstractā€”Recent years have seen rapidly growing interest in the development of networks of vehicles for which adaptive cooperation and autonomous execution become a necessity. In the paper, we develop a distributed reconfigurable control law to distribute unicycle-type vehicles evenly on a circle surrounding a moving target for the escorting and patrolling missions. The even distribution of the vehicles provides the best overall coverage of the target in its surroundings. It is shown that as the target moves, the group formation moves and rotates around the target to keep the target around the formation centroid. When some vehicles in the group are lost due to faults, the remaining vehicles recognize the loss and adaptively reconfigure themselves to a new evenly distributed formation

    A Distributed Reconfigurable Control Law for Escorting and Patrolling Missions using Teams of Unicycles

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    The scorpions of Hainan Island, China (Arachnida: Scorpiones)

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    The redescriptions and illustrations of three species, Isometrus (Isometrus) maculatus (DeGeer, 1778), Lychas mucronatus (Fabricius, 1798) (Buthidae), and Liocheles australasiae (Fabricius, 1775) (Hemiscorpiidae) from Hainan Island, China are presented. Distribution data and updated key of Hainan scorpions are provided
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