98 research outputs found

    Evolving Optical Networks for Latency-Sensitive Smart-Grid Communications via Optical Time Slice Switching (OTSS) Technologies

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    In this paper, we proposed a novel OTSS-assisted optical network architecture for smart-grid communication networks, which has unique requirements for low-latency connections. Illustrative results show that, OTSS can provide extremely better performance in latency and blocking probability than conventional flexi-grid optical networks.Comment: IEEE Photonics Society 1st Place Best Poster Award, on CLEO-PR/OECC/PGC 201

    Stimulus Pulse-Based Distributed Control for the Locomotion of a UBot Modular Robot

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    A distributed control algorithm based on a stimulus pulse signal is proposed in this paper for the locomotion of a Modular Self-reconfigurable Robot (MSRR). This approach can adapt effectively to the dynamic changes in the MSRR's topological configuration: the functional role of the configuration can be recognized through local topology detection, dynamic ID address allocation and local topology matching, such that the features of the entire configuration can be identified and thereby the corresponding stimulus signals can be chosen to control the whole system for coordinated locomotion. This approach has advantages over centralized control in terms of flexibility and robustness, and communication efficiency is not limited by the module number, which can realize coordinated locomotion control conveniently (especially for configurations made up of massive modules and characterized by a chain style or a quadruped style)

    Research on deformation monitoring of surrounding rock based on weak fiber grating sensing technology

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    The prominent contradiction between high ground stress and low strength of surrounding rock in deep strata of coal mine leads to large deformation and instability disaster after roadway excavation. In order to grasp the internal deformation of surrounding rock before and after roadway excavation and support in time, this study developed a quasi-distributed large-range strain sensor cable based on weak fiber grating sensing technology, and realized the 1 m-level spacing arrangement of deformation measuring points in surrounding rock. The test performance of the sensor cable is mastered through the indoor calibration test. The test results show that the strain range of the developed strain sensing cable is not less than 0.04, the sensitivity is 1.23 pm/με, and the accuracy level is 0.5. It belongs to the high-precision sensor and has good repeatability and linearity. Field industrial test was carried out in deep rock roadway of No. 4 Coal Mine of Pingdingshan Tian’an Coal Shares The results show that: The strain value of surrounding rock decreases with the increase of hole depth. The strain value of surrounding rock within 4 m is larger, and the strain value outside 7 m is smaller and tends to be stable. The strain of roadway surrounding rock mainly occurs within 30 days after roadway repair, and then the strain increase of roadway surrounding rock gradually decreases and tends to be stable. Taking the rapid convergence position of strain rate to 0 as the boundary of surrounding rock loose zone, the boundary of roadway side and top loose zone is 5 m, and the boundary of shoulder loose zone is 4 m. Through the comprehensive application of weak fiber grating technology and time division multiplexing technology, the strain optical cable greatly improves the multiplexing capacity of optical fiber sensing network and meets the large range and fine online monitoring requirements of surrounding rock deformation monitoring in deep roadway of coal mine. Through technical application, the internal deformation characteristics of surrounding rock of deep roadway in coal mine and the spatio-temporal evolution law of loose circle can be mastered in time, which provides scientific basic data for the stability control decision of surrounding rock of deep roadway

    Bio-inspired locomotion control for UBot self-reconfigurable modular robot

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    This paper first presents a mathematic CPG (central pattern generator) model which has been developed based on the characteristics of a self-reconfigurable modular robot (UBot)'s modules with universal joints. Then, a bionic motion neural control network based on the CPG is proposed to solve the problem of multi-mode locomotion control problem in the complex environment. The bionic network is composed of perceptual neurons, CPG phase modulation network and motor neurons, so it can coordinate the walking and creeping gait of the modular robot before and after deformation, and adapt to autonomous movement in the complex environment with challenging features, such as steps, slopes and obstacles. Finally, the proposed motion control algorithm is verified by experiments

    Characterization of a multidrug-resistant porcine Klebsiella pneumoniae sequence type 11 strain coharboring blaKPC-2 and fosA3 on two novel hybrid plasmids

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    The occurrence of carbapenemase-producing Enterobacteriaceae (CPE) poses a considerable risk for public health. The gene for Klebsiella pneumoniae carbapenemase-2 (KPC-2) has been reported in many countries worldwide, and KPC-2-producing strains are mainly of human origin. In this study, we identified two novel hybrid plasmids that carry either blaKPC-2 or the fosfomycin resistance gene fosA3 in the multiresistant K. pneumoniae isolate K15 of swine origin in China. The blaKPC-2-bearing plasmid pK15-KPC was a fusion derivative of an IncF33:A−:B− incompatibility group (Inc) plasmid and chromosomal sequences of K. pneumoniae (CSKP). A 5-bp direct target sequence duplication (GACTA) was identified at the boundaries of the CSKP, suggesting that the integration might have been due to a transposition event. The blaKPC-2 gene on pK15-KPC was in a derivative of ΔTn6296-1. The multireplicon fosA3-carrying IncN-IncR plasmid pK15-FOS also showed a mosaic structure, possibly originating from a recombination between an epidemic fosA3-carrying pHN7A8-like plasmid and a pKPC-LK30-like IncR plasmid. Stability tests demonstrated that both novel hybrid plasmids were stably maintained in the original host without antibiotic selection but were lost from the transformants after approximately 200 generations. This is apparently the first description of a porcine sequence type 11 (ST11) K. pneumoniae isolate coproducing KPC-2 and FosA3 via pK15-KPC and pK15-FOS, respectively. The multidrug resistance (MDR) phenotype of this high-risk K. pneumoniae isolate may contribute to its spread and its persistence

    A Synthetic Algorithm for Tracking a Moving Object in a Multiple-Dynamic Obstacles Environment Based on Kinematically Planar Redundant Manipulators

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    This paper presents a synthetic algorithm for tracking a moving object in a multiple-dynamic obstacles environment based on kinematically planar manipulators. By observing the motions of the object and obstacles, Spline filter associated with polynomial fitting is utilized to predict their moving paths for a period of time in the future. Several feasible paths for the manipulator in Cartesian space can be planned according to the predicted moving paths and the defined feasibility criterion. The shortest one among these feasible paths is selected as the optimized path. Then the real-time path along the optimized path is planned for the manipulator to track the moving object in real-time. To improve the convergence rate of tracking, a virtual controller based on PD controller is designed to adaptively adjust the real-time path. In the process of tracking, the null space of inverse kinematic and the local rotation coordinate method (LRCM) are utilized for the arms and the end-effector to avoid obstacles, respectively. Finally, the moving object in a multiple-dynamic obstacles environment is thus tracked via real-time updating the joint angles of manipulator according to the iterative method. Simulation results show that the proposed algorithm is feasible to track a moving object in a multiple-dynamic obstacles environment

    Monocular Vision-Based Pose Determination in Close Proximity for Low Impact Docking

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    Pose determination in close proximity is critical for space missions in which monocular vision is one of the most promising solutions. Although numerous approaches such as using artificial beacons or specific shapes on spacecrafts have proved to be effective, the high individuation and the large time delay limit their use in low impact docking. This paper proposes a unified framework to determinate the relative pose between two docking mechanisms by treating their guide petals as measurement objects. Fusing the pose information of one docking mechanism to simplify image processing and creating an intermediate coordinate system to solve the perspective-n-point problem greatly improve the real-time performance and the robustness of the method. Experimental results show that the position measurement error is within 3.7 mm, while the rotation error around docking direction is less than 0.16°, corresponding to a measurement time reduction of 85%
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