This paper presents a MARG Sensors based walking motion analysis method that can be used for rehabilitation treatment evaluation under ambulatory conditions in daily lives. A commercial inertial measure unit MTx is fi...
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This paper presents a MARG Sensors based walking motion analysis method that can be used for rehabilitation treatment evaluation under ambulatory conditions in daily lives. A commercial inertial measure unit MTx is fixed on human shank segment. Then digital data box worn on the waist transmits the raw data to laptop with Blue-tooth for post processing. Subjects are required to perform level walking and upstairs walking respectively. After the initial alignment and quaternion convergence, the proposed method fuses the inertial data using Kalman filter based on quaternion. Walking trajectory and knee joint angle are estimated and validated by available ground truth. Experiment results demonstrate that the proposed method has a good performance at both motion patterns. It also shows that no significant drifts exist in the overall results presented in the paper. The method can also be adapted to measure other sites of articulation such as ankle and elbow.
In addition to simplicity, the DTC of the IM allows a good torque control in steady-state and transient operating conditions. However, high torque ripple is produced, which is reflected in speed estimation responses. ...
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ISBN:
(纸本)9781849198158
In addition to simplicity, the DTC of the IM allows a good torque control in steady-state and transient operating conditions. However, high torque ripple is produced, which is reflected in speed estimation responses. It also increases acoustical noise and makes the voltage source inverter operated in high and variable switching frequency, requiring a high sampling frequency. In this paper, a simple effective ANN-based DTC of the induction machine is proposed. Neural networks with a simple architecture are designed and implemented in influential points of the direct torque control block of the three phase induction machine in order to improve its dynamic performance while preserving the DTC structure simplicity as much as possible. In particular, this paper proposes to reduce, on the one hand, the torque ripple and commutation frequency. Neural comparators are used to select the appropriate bandwidth for the torque and flux hysteresis controllers. Their aim is to optimize the ripple level in the developed torque and flux. On the other hand, a neural speed controller is designed in order to improve the system ability to respond rapidly to changes in process variables and mitigate the effects of external perturbations. The performance of the proposed control are tested in simulation and highlighted by comparing to the conventional DTC control based on conventional hysteresis comparators and conventional PI speed controller. The obtained results show the feasibility and good performances of the proposed control.
Augmented finite transition systems generalize nondeterministic transition systems with additional liveness conditions. We propose efficient algorithms for synthesizing control protocols for augmented finite transitio...
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ISBN:
(纸本)9781479932757
Augmented finite transition systems generalize nondeterministic transition systems with additional liveness conditions. We propose efficient algorithms for synthesizing control protocols for augmented finite transition systems to satisfy high-level specifications expressed in a fragment of linear temporal logic (LTL). We then use these algorithms within a framework for switching protocol synthesis for discrete-time dynamical systems, where augmented finite transition systems are used for abstracting the underlying dynamics. We introduce a notion of minimality for abstractions of certain fidelity and show that such minimal abstractions can be exactly computed for switched affine systems. Additionally, based on this framework, we present a procedure for computing digitally implementable switching protocols for continuous-time systems. The effectiveness of the proposed framework is illustrated through two examples of temperature control for buildings.
This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal pe...
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This paper investigates the fault-tolerant shape control (FTSC) problem for stochastic distribution systems. The available information for the addressed problem is the input and the measurable output Probability Densi...
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ISBN:
(纸本)9781479932757
This paper investigates the fault-tolerant shape control (FTSC) problem for stochastic distribution systems. The available information for the addressed problem is the input and the measurable output Probability Density Function (PDF) of the system. The system is subject to actuator faults. In this case, the main objective is to achieve fault-tolerant shape control so that the output PDF can track a given target PDF shape even in the presence of faults. In this framework, an effective novel FTSC strategy is proposed based on the online estimation of the actuator faults, which includes a normal control law and an adaptive compensation control law simultaneously. The former can track the given output PDF with optimized performance index in the fault-free case, while the latter can automatically reduce (or even eliminate) the impact of faults for the given PDF shape. Finally, the effectiveness of the proposed design method is illustrated via a numerical example.
Recently, researchers have discovered unexpected bumps in the detection rate curve of yet another steganographic scheme (YASS). We refer to this abnormal phenomenon as non-monotonic security performance. This paper fi...
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Support vector machine is one of the most successful machine learning methods in image processing and computer vision in the past decades. However, its performance strongly depends on the training data, which are some...
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Support vector machine is one of the most successful machine learning methods in image processing and computer vision in the past decades. However, its performance strongly depends on the training data, which are sometimes expensive and of low quality. Specifically, in many real applications, such as face recognition, the images are rarely perfectly aligned, thus the misalignment between training and testing data impairs the performance. In this paper, we propose a strategy to compensate the misalignment between images while learning the classifier without looking at the testing samples. Specifically, some certain critical transformations are inferred and applied to training samples to alleviate the effect of the worst case of possible misalignment. The resulted large margin classifier generalizes better than traditional SVM, especially when there is misalignment. Experimental results on real image data sets show the efficacy of the proposed algorithm.
A direct fairing ship hull generation method is proposed in this research with three kinds of characteristic parameterized curves confined hull shape and using genetic algorithm optimized for design requirements. The ...
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A direct fairing ship hull generation method is proposed in this research with three kinds of characteristic parameterized curves confined hull shape and using genetic algorithm optimized for design requirements. The proposed method provides the basis of rapid prototype conceptual design and benefit designers creation and modification in a large range of parameters.
A Bayesian optimization algorithm (BOA) belongs to estimation of distribution algorithms (EDAs). It is characterized by combining a Bayesian network and evolutionary algorithms to solve nearly decomposable optimizatio...
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ISBN:
(纸本)9781479938414
A Bayesian optimization algorithm (BOA) belongs to estimation of distribution algorithms (EDAs). It is characterized by combining a Bayesian network and evolutionary algorithms to solve nearly decomposable optimization problems. BOA is less popularly applied to solve high dimensionality complex optimization problems. A key reason is that the cost of training all dimensions by BOA becomes expensive with the increase of problem dimensionality. Since data are relatively sparse in a high dimensional space, even though BOA can train all dimensions simultaneously, the interdependent relations between different dimensions are difficult to learn. Its search ability is thus significantly reduced. In this paper, we propose a team of Bayesian optimization algorithms (TBOA) to search and learn dimensionality. TBOA consists of multiple BOAs, in which each BOA corresponds to a dimension of the solution domain and it is responsible for the search of this dimension's value region. The proposed TBOA is used to solve the real problem of task assignment in heterogeneous computing systems. Extensive experiments demonstrate that the computational cost of the overall training in TBOA is decreased very significantly while keeping high solution accuracy.
As an unsupervised learning method, clustering methods plays an important role in quality data mining and various other applications. This work investigates them based on swarm intelligence, introduces a new intellige...
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As an unsupervised learning method, clustering methods plays an important role in quality data mining and various other applications. This work investigates them based on swarm intelligence, introduces a new intelligence algorithm called mussels wandering optimization (MWO) to the data clustering field, and proposes a new clustering algorithm by combining K-means clustering method and MWO. Tests on six standard data sets are performed. The results demonstrate the validity and superiority of the proposed method over some representative clustering ones.
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