The visualization of the coronary vasculature is of utmost importance in interventional cardiology. Intravascular surgical robots assist the practitioners to perform the complex procedure while protecting them from th...
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ISBN:
(纸本)9781479927456
The visualization of the coronary vasculature is of utmost importance in interventional cardiology. Intravascular surgical robots assist the practitioners to perform the complex procedure while protecting them from the tremendous occupational hazards. Robotic surgical simulation aims to provide support for the learners in both efficiency and convenience. The blood vessels especially the coronary arteries with rich details are the key part of the anatomic scenario of the virtual training system. The variations in diameters and directions make the segmentation of the coronary arteries a difficult work. In this paper, a robust and semi-automatic approach for the segmentation of the coronary arteries is developed. The approach is based on the multi-scale tubular enhancement and an improved geodesic active contours model. The demonstrated approach firstly enhances the tubular objects by computing their “vesselness”. Next the edge potential maps are calculated based on the enhanced information. Meanwhile, the initial contours are generated by a modified fast marching method. Then the actual wave fronts evolution extracts the details of the coronary arteries. Finally the visualization model is organized based on the segmentation results by the marching cubes method. This approach has been proved successful for the visualization of the coronary arteries based on the CTA information.
In this paper,an artificial neural network is proposed to estimate knee joint angle in hybrid activation of knee extension motion,including voluntary muscle contraction and functional electrical stimulation(FES) induc...
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ISBN:
(纸本)9781479900305
In this paper,an artificial neural network is proposed to estimate knee joint angle in hybrid activation of knee extension motion,including voluntary muscle contraction and functional electrical stimulation(FES) induced *** electromyography(EMG) signals of three muscles responsible for knee extension and FES parameter which describe the FES intensity are used as input vector of the neural network,while the estimated knee angle is the *** the experiment, FES with different combinations of parameters(pulse amplitude and pulse width) was delivered to the rectus femoris muscle of a healthy male subject when the knee was in a periodic extension motion by voluntary muscle *** EMG signals of three muscles,parameters of FES as well as the actual knee angle were ***,there were 52,233 and 17,420 sampling points corresponding to 261 and 87 seconds used to train and validate the neural *** result shows the trained network has a satisfactory performance on knee joint angle estimation whose output well follows the curve of actual knee angle. Root mean square error between estimated angle and actual angle is employed to represent the estimation accuracy which is 5.07 degree according to the experimental data.
Social networking sites provide a convenient way for users to participate in discussion groups and communicate with others. While users situate in and enjoy such a social environment, it is important for various secur...
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ISBN:
(纸本)9781467362146
Social networking sites provide a convenient way for users to participate in discussion groups and communicate with others. While users situate in and enjoy such a social environment, it is important for various security related applications to understand, model and analyze participating users' behavior. In this paper, we make an attempt to model and predict user participation behavior in discussion groups of social networking sites. Our work employs a feature-based approach, which considers four types of features: thread features, content similarity, user behavior and social features. We conduct an empirical study on a popular social networking site in China, ***. The experimental results show the effectiveness of our approach.
A horizontal exoskeleton for lower limb rehabilitation called iLeg has been developed by our laboratory which consists of two 3-DOF (degrees of freedom) robotic leg orthoses. This paper proposes a position-based imped...
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ISBN:
(纸本)9781479927456
A horizontal exoskeleton for lower limb rehabilitation called iLeg has been developed by our laboratory which consists of two 3-DOF (degrees of freedom) robotic leg orthoses. This paper proposes a position-based impedance control with the compensation of BP NNs (back propagation neural networks) for the exoskeleton. Based on the control scheme, the task-oriented active training is investigated where impedance parameters are self-adjusted to movement deviation and patient activities with fuzzy logic. An adaptive haptic interface of active compliance is ensured to provide positive feedback to patients when their effort is desired or negative otherwise, which encourages patients to practice the desired movement following the predefined directed path. Besides, the timing freedom is separated from spatial trajectory and determined by patients. Voluntary effort hence becomes a requirement during the exercises, no effort no movement, so that active contribution of patients is highly motivated. Simulation results have verified the feasibility of the control scheme and the training strategy. An active compliant environment is created with adaptive haptic interface for task-oriented patient-driven training of multi-joint coordination.
This paper considers the distributed attitude tracking problem of multiple spacecraft with disturbances and unknown inertia matrices. Based on the relative attitudes and angular velocities of neighboring spacecraft, w...
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This paper considers the distributed attitude tracking problem of multiple spacecraft with disturbances and unknown inertia matrices. Based on the relative attitudes and angular velocities of neighboring spacecraft, we design a distributed robust controller to each follower to guarantee that the attitude errors between the followers and the leader converge to zero for any communication graph containing a directed spanning tree with the leader as the root. To deal with the problem of parameters uncertainties, we further propose a distributed adaptive sliding mode controller, under which the system is globally robust with respect to external disturbances and inertia matrices uncertainties.
The navigation precision drops rapidly when MIMU (Micro Inertial Measurement Unit) works alone. Odometer data are easy to get on land vehicle, but the performance of integration system of MIMU/odometer is not enhanced...
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ISBN:
(纸本)9781479925667
The navigation precision drops rapidly when MIMU (Micro Inertial Measurement Unit) works alone. Odometer data are easy to get on land vehicle, but the performance of integration system of MIMU/odometer is not enhanced obviously. In this work, a novel method is designed using nonholonomic constraints. When vehicle travels without slide and jump, the velocity in the plane perpendicular to forward direction is zero, as well as acceleration. Taking velocity constraint and acceleration constraint as measurement value, new measurement models are established. Integrated navigation algorithm is designed with the help of Kalman filter. With this method, the position error is 150m after 600s, and heading attitude error is 0.1°, comparing the result that the position error expands to 300m after 150s only aided by odometer.
In this paper,a wavelet packet based adaptive filter-bank construction method is proposed,with additive Fisher ratio used as wavelet packet tree pruning criterion.A novel acoustic feature named discriminative band wav...
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In this paper,a wavelet packet based adaptive filter-bank construction method is proposed,with additive Fisher ratio used as wavelet packet tree pruning criterion.A novel acoustic feature named discriminative band wavelet packet power coefficients(db-WPPC) is proposed and on this basis,a speech emotion recognition system is *** results show that the proposed feature improves emotion recognition performance over the conventional MFCC feature.
Subspace learning has long been a fundamental yet important problem of modeling data distributions. In this paper, we propose to learn multiple linear subspaces in a supervised way for multi-class classification. To t...
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ISBN:
(纸本)9781479925667
Subspace learning has long been a fundamental yet important problem of modeling data distributions. In this paper, we propose to learn multiple linear subspaces in a supervised way for multi-class classification. To this end, a discriminative term redefining decision margin in terms of reconstruction error is incorporated into the model. The term enjoys similar properties of hinge loss function to the benefit of classification and leads to a training process seeking the balance between unsupervised learning and supervised learning. In the experiments on written digits dataset, our algorithm outperforms other methods proposed recently in both accuracy and computation efficiency.
This paper is concerned with the problem of data-driven predictive control for networked controlsystems (NCSs), which is designed by applying the subspace matrices technique, obtained directly from the input/output d...
This paper is concerned with the problem of data-driven predictive control for networked controlsystems (NCSs), which is designed by applying the subspace matrices technique, obtained directly from the input/output data transferred from networks. The networked predictive control consists of the control prediction generator and network delay compensator. The control prediction generator provides a set of future control predictions to make the closed-loop system achieve the desired control performance and the network delay compensator eliminates the effects of the network transmission delay. The effectiveness and superiority of the proposed method is demonstrated in simulation as well as experiment study.
The problem of robust stabilization for a class of SISO uncertain nonlinear Differential-Algebraic Eqyatuion subsystems is considered in this paper. The robust stabilization controller is proposed based on backsteppin...
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