986 research outputs found

    Early Turn-taking Prediction with Spiking Neural Networks for Human Robot Collaboration

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    Turn-taking is essential to the structure of human teamwork. Humans are typically aware of team members' intention to keep or relinquish their turn before a turn switch, where the responsibility of working on a shared task is shifted. Future co-robots are also expected to provide such competence. To that end, this paper proposes the Cognitive Turn-taking Model (CTTM), which leverages cognitive models (i.e., Spiking Neural Network) to achieve early turn-taking prediction. The CTTM framework can process multimodal human communication cues (both implicit and explicit) and predict human turn-taking intentions in an early stage. The proposed framework is tested on a simulated surgical procedure, where a robotic scrub nurse predicts the surgeon's turn-taking intention. It was found that the proposed CTTM framework outperforms the state-of-the-art turn-taking prediction algorithms by a large margin. It also outperforms humans when presented with partial observations of communication cues (i.e., less than 40% of full actions). This early prediction capability enables robots to initiate turn-taking actions at an early stage, which facilitates collaboration and increases overall efficiency.Comment: Submitted to IEEE International Conference on Robotics and Automation (ICRA) 201

    On a generalization of Lie(kk): a CataLAnKe theorem

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    We define a generalization of the free Lie algebra based on an nn-ary commutator and call it the free LAnKe. We show that the action of the symmetric group S2n−1S_{2n-1} on the multilinear component with 2n−12n-1 generators is given by the representation S2n−11S^{2^{n-1}1}, whose dimension is the nnth Catalan number. An application involving Specht modules of staircase shape is presented. We also introduce a conjecture that extends the relation between the Whitehouse representation and Lie(kk).Comment: 14 page

    Seeing Beyond: Real-time Ultrasound Image Integration in Augmented Reality Based Telementoring

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    Ultrasound imaging, when aptly integrated with augmented reality based medical telementoring, may be beneficial as an assistive tool in a range of trauma procedures including removal of foreign objects from blast injuries and central or peripheral venous access. Expected benefits include reduced procedure completion time, higher efficiency, and higher incision accuracy. This paper describes the implementation strategy selected for the integration of real time ultrasound imaging in the trainee view of a telementoring system. The proposed strategy augments the view of the trainee surgeon by displaying the ultrasound image directly below and parallel to the ultrasound transducer. The developed system features a fiducial marker based tracking approach employing a triplanar geometric fixture. An experiment was designed to demonstrate the system function and validate its performance

    Gaze, Posture and Gesture Recognition to Minimize Focus Shifts for Intelligent Operating Rooms in a Collaborative Support System

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    This paper describes the design of intelligent, collaborative operating rooms based on highly intuitive, natural and multimodal interaction. Intelligent operating rooms minimize surgeon’s focus shifts by minimizing both the focus spatial offset (distance moved by surgeon’s head or gaze to the new target) and the movement spatial offset (distance surgeon covers physically). These spatio-temporal measures have an impact on the surgeon’s performance in the operating room. I describe how machine vision techniques are used to extract spatio-temporal measures and to interact with the system, and how computer graphics techniques can be used to display visual medical information effectively and rapidly. Design considerations are discussed and examples showing the feasibility of the different approaches are presented

    Action of the Symmetric Group on the Free LAnKe: A CataLAnKe Theorem

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    We initiate a study of the representation of the symmetric group on the multilinear component of an n-ary generalization of the free Lie algebra, which we call a free LAnKe. Our central result is that the representation of the symmetric group S2n−1 on the multilinear component of the free LAnKe with S2n−1 generators is given by an irreducible representation whose dimension is the nth Catalan number. This leads to a more general result on eigenspaces of a certain linear operator. A decomposition, into irreducibles, of the representation of S3n−2 on the multilinear component the free LAnKe with 3n − 2 generators is also presented. We also obtain a new presentation of Specht modules of shape λ, where λ has strictly decreasing column lengths, as a consequence of our eigenspace result

    Real-Time Hand Shape Classification

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    The problem of hand shape classification is challenging since a hand is characterized by a large number of degrees of freedom. Numerous shape descriptors have been proposed and applied over the years to estimate and classify hand poses in reasonable time. In this paper we discuss our parallel framework for real-time hand shape classification applicable in real-time applications. We show how the number of gallery images influences the classification accuracy and execution time of the parallel algorithm. We present the speedup and efficiency analyses that prove the efficacy of the parallel implementation. Noteworthy, different methods can be used at each step of our parallel framework. Here, we combine the shape contexts with the appearance-based techniques to enhance the robustness of the algorithm and to increase the classification score. An extensive experimental study proves the superiority of the proposed approach over existing state-of-the-art methods.Comment: 11 page

    The Role of Surface Area in Catalytic Gasification of Biomass

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    Gasification of biomass has the potential to provide a carbon-negative source of liquid fuels. The current limited use of gasification is due in part to the high temperatures necessary to achieve high conversion levels. These temperatures can be lowered by the use of catalysts, but the mechanisms by which catalysts affect the reaction rate are not fully understood. Here, the structural component of potassium carbonate’s role in the gasification process was examined. Samples of pinewood sawdust were impregnated with potassium carbonate, then pyrolyzed with N2 in a fixed bed reactor at 750°C (heater thermocouple reading). Half of the char was washed with deionized water twice to remove potassium ions. The char was ground to a 150 micron diameter. Gasification of the samples was performed using CO2 at 750°C and 900°C. Reaction rates over time were compared to the reaction rate of pure pinewood sawdust char. The pure char was then impregnated with K2CO3 and gasified, allowing a comparison to be made between the efficacy of impregnating the sawdust versus the char. Results show that after washing, the impregnated char shows similar or decreased reactivity compared to the pure char. Preliminary results do suggest that impregnation of the sawdust leads to greater reactivity over time than impregnation of the char. The results do not suggest a strong influence of surface area change during impregnation on the reactivity of the char
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