A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset(BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial partic...
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A novel binary particle swarm optimization for frequent item sets mining from high-dimensional dataset(BPSO-HD) was proposed, where two improvements were joined. Firstly, the dimensionality reduction of initial particles was designed to ensure the reasonable initial fitness, and then, the dynamically dimensionality cutting of dataset was built to decrease the search space. Based on four high-dimensional datasets, BPSO-HD was compared with Apriori to test its reliability, and was compared with the ordinary BPSO and quantum swarm evolutionary(QSE) to prove its advantages. The experiments show that the results given by BPSO-HD is reliable and better than the results generated by BPSO and QSE.
As widely used in aircrafts, helicopters and UAVs, carbon-fiber-reinforced composites were chosen for the research in this paper. Finite element models of composite cantilever beams were established through ANSYS soft...
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We present here a new type of cold atom interferometry gravimeter based on Bragg diffraction, which is able to increase the gravity measurement sensitivity and stability of common Raman atom gravimeters significantly....
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Fault prognosis is one of the key techniques for prognosis and health management,and an effective fault feature can improve prediction accuracy and performance. A novel approach of feature extraction for fault prognos...
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Fault prognosis is one of the key techniques for prognosis and health management,and an effective fault feature can improve prediction accuracy and performance. A novel approach of feature extraction for fault prognosis based on fault trend analysis was proposed in this paper. In order to describe the ability of tracking fault growth process,definitions and calculations of fault trackability was developed, and the feature which had the maximum fault trackability was selected for fault prognosis. The vibration data in bearing life tests were used to verify the effectiveness of the method was proposed. The results showed that the trackability of energy entropy for bearing fault growth was the maximum,and it was the best fault feature among selected features root mean square( RMS),kurtosis,new moment and energy entropy. The proposed approach can provide a better strategy for fault feature extraction of bearings in order to improve prediction accuracy.
This paper presents a fault-tolerant control(FTC) with integration of neural network(NN) and multivariable sliding mode approaches for an air-breathing hypersonic vehicle(AHV),where both partial loss of effectiveness ...
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ISBN:
(纸本)9781538629185
This paper presents a fault-tolerant control(FTC) with integration of neural network(NN) and multivariable sliding mode approaches for an air-breathing hypersonic vehicle(AHV),where both partial loss of effectiveness faults and bias faults in actuators are considered.A radial bias function NN(RBFNN) is derived using on-line updating law to approximate the lumped uncertainties,which consists of actuator faults and system uncertainties.A finite-time convergent multivariable sliding mode control(SMC) is developed against system uncertainties and actuator *** results of a generic AHV are provided to demonstrate the effectiveness of the proposed FTC scheme.
More and more robots are applied to scientific expedition, but they encounter severe limitations on continuous working as most of them powered by batteries or fuel. Base on this, a multiple wing-sail land-yacht robot ...
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More and more robots are applied to scientific expedition, but they encounter severe limitations on continuous working as most of them powered by batteries or fuel. Base on this, a multiple wing-sail land-yacht robot is designed and manufactured. Land yacht robot is a new type of mobile robot powered by wind through the use of sail. It includes frame body, wing-sail driven system, turning system, wing-sail rotation system and control system. After assembly, land-yacht robot is test by start wind speed and linear motion experiment. It shows that robot can start up when wind speed in 3m/s. the velocity of robot can reach 3.11m/s when wind speed is 13.6m/s. The results indicate that the multiple wing-sail land-yacht robot could satisfy the requirements of scientific expedition.
Dynamic analysis of reciprocating compressor with two joint clearances is studied. In order to investigate the nonlinearity of the system, the dynamic equation of the system is established based on Lagrange method. By...
Dynamic analysis of reciprocating compressor with two joint clearances is studied. In order to investigate the nonlinearity of the system, the dynamic equation of the system is established based on Lagrange method. By changing the parameters of the system, the response of the system under different sizes of joint clearance and crankshaft speed is obtained. From the simulation results of the system, we can see the influence of crankshaft speed and joint clearance on the system dynamics. By calculating the phase diagrams and the maximum Lyapunov exponents, it can be concluded that the motion of the system is chaotic.
We propose a novel monocular visual odometry (VO) system called UnDeepVO in this paper. UnDeepVO is able to estimate the 6-DoF pose of a monocular camera and the depth of its view by using deep neural networks. There ...
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We propose a novel monocular visual odometry (VO) system called UnDeepVO in this paper. UnDeepVO is able to estimate the 6-DoF pose of a monocular camera and the depth of its view by using deep neural networks. There are two salient features of the proposed UnDeepVo:one is the unsupervised deep learning scheme, and the other is the absolute scale recovery. Specifically, we train UnDeepVoby using stereo image pairs to recover the scale but test it by using consecutive monocular images. Thus, UnDeepVO is a monocular system. The loss function defined for training the networks is based on spatial and temporal dense information. A system overview is shown in Fig. 1. The experiments on KITTI dataset show our UnDeepVO achieves good performance in terms of pose accuracy.
Aiming to diagnosis the mechanical fault precisely, the current research is proposing a method based on the local mean decomposition (LMD) Shannon entropy and improved fuzzy f-means flustering (IFCM). The features are...
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Aiming to diagnosis the mechanical fault precisely, the current research is proposing a method based on the local mean decomposition (LMD) Shannon entropy and improved fuzzy f-means flustering (IFCM). The features are first extracted by using the time-frequency domain method LMD and the Shannon entropy is used to process the original separated product functions (PF) so as to extract the original features. However, the extracted original features are still with high dimensional and include superfluous information. The nonlinear multi-features fusion technique LTSA is used to merge the features and reduce the dimension. Then, based on the extracted features, the IFCM model is used to achieve the mechanical fault diagnosis. In this model, a feature cluster determine function is established to achieve the weighted factor to achieve a better category effect. Case of a bearing test was analyzed and the results proved the effectiveness of the methodology.
Sliding process between asperities of machined metal surface is important to analyse wear mechanisms. Elastic-plastic sliding asperity model based on fractal geometry is proposed in this paper to extend the sliding pr...
Sliding process between asperities of machined metal surface is important to analyse wear mechanisms. Elastic-plastic sliding asperity model based on fractal geometry is proposed in this paper to extend the sliding process of single micro-asperity to a macro-asperity. The contact force, the critical interference and residual interference are calculated with fractal dimension D and fractal roughness G in the multiscale views. The influence of fractal parameters on normal and tangential contact force are studied. The results of the simulation show that the plastic deformation and residual interference are the main factors affecting the contacting force and asperity radius. For smaller G and bigger D surfaces, the sliding interaction of asperities is less remarkable and the plastic force accounts for less in the contact force.
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