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The movements of smoldering cotton wick smoke and flaming diesel oil smoke plumes in thermally stratified environments in a small scale enclosure were investigated by experiments and CFD simulations. The reasonably good agreements...
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The movements of smoldering cotton wick smoke and flaming diesel oil smoke plumes in thermally stratified environments in a small scale enclosure were investigated by experiments and CFD simulations. The reasonably good agreements of the experimental and simulated results indicated that the thermally stratified environments intensified the decreases of the axial temperatures and velocities of a fire smoke plume. The previous integral equation was shown to underestimate the maximum smoke rises, and also unable to explain the differences of the maximum heights of low and high density smoke with the same stratification and outlet conditions. An improved integral equation and an effective detection method were introduced and discussed.
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摘要 :
The movements of smoldering cotton wick smoke and flaming diesel oil smoke plumes in thermally stratified environments in a small scale enclosure were investigated by experiments and CFD simulations. The reasonably good agreements...
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The movements of smoldering cotton wick smoke and flaming diesel oil smoke plumes in thermally stratified environments in a small scale enclosure were investigated by experiments and CFD simulations. The reasonably good agreements of the experimental and simulated results indicated that the thermally stratified environments intensified the decreases of the axial temperatures and velocities of a fire smoke plume. The previous integral equation was shown to underestimate the maximum smoke rises, and also unable to explain the differences of the maximum heights of low and high density smoke with the same stratification and outlet conditions. An improved integral equation and an effective detection method were introduced and discussed.
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This paper devotes to addressing the issue of precise formation control with local collision avoidance based on the artificial potential fields. Firstly, an improved artificial potential field, named tilted potential field, is des...
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This paper devotes to addressing the issue of precise formation control with local collision avoidance based on the artificial potential fields. Firstly, an improved artificial potential field, named tilted potential field, is designed in this paper, which has a minimum and a saddle that help to form the formation. Then, based on the tilted potential field, a precise formation control law for the multi-agent systems is designed to make them form the desired formation in most situations and avoid collisions between communicating agents without using the minimum rigid graph. Besides, this paper gives the complete stability analysis and corresponding stability conditions of the control law based on the Lyapunov function. Finally, in order to better illustrate the advantages and disadvantages of the proposed controller, the numerical simulations under some special conditions are carried out and the results are analyzed carefully.
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Rough sets are widely used in feature evaluation and attribute reduction and a number of rough set based evaluation functions and search algorithms were reported.However,little attention has been paid to compute and compare stabil...
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Rough sets are widely used in feature evaluation and attribute reduction and a number of rough set based evaluation functions and search algorithms were reported.However,little attention has been paid to compute and compare stability of feature evaluation functions.In this work,we introduce three coefficients to calculate the stabilities of feature significance via perturbing samples.Experimental results show that entropy and fuzzy entropy based evaluation functions are more stable than the others and fuzzy rough set based functions are stable compared with the crisp functions.These results give a guideline to select feature evaluation for different applications.
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With the emergence of big data of TB and PB geological and mineral resources, the storage of large geological data has become a worldwide problem puzzling geologists. The traditional storage and service model of geological data is...
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With the emergence of big data of TB and PB geological and mineral resources, the storage of large geological data has become a worldwide problem puzzling geologists. The traditional storage and service model of geological data is facing a great challenge. In this paper, a new data storage method of geology and mineral resources based on cloud computing environment is put forward combined with Hadoop. This method is compared with traditional Oracle database storage method. The experimental results show that the storage method proposed in this paper is more efficient than the traditional method. At the same time, it effectively solves the problem of small file storage in Hadoop storage. The research results provide a new technical support for the storage and management of geological and mineral data.
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摘要 :
With the emergence of big data of TB and PB geological and mineral resources, the storage of large geological data has become a worldwide problem puzzling geologists. The traditional storage and service model of geological data is...
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With the emergence of big data of TB and PB geological and mineral resources, the storage of large geological data has become a worldwide problem puzzling geologists. The traditional storage and service model of geological data is facing a great challenge. In this paper, a new data storage method of geology and mineral resources based on cloud computing environment is put forward combined with Hadoop. This method is compared with traditional Oracle database storage method. The experimental results show that the storage method proposed in this paper is more efficient than the traditional method. At the same time, it effectively solves the problem of small file storage in Hadoop storage. The research results provide a new technical support for the storage and management of geological and mineral data.
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The active return of the steering wheel is playing a significant role in Electric Power Steering(EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity activ...
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The active return of the steering wheel is playing a significant role in Electric Power Steering(EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity active return-to-center(RTC) control strategy based on single neuron adaptive PID control is proposed in the paper. In the newly-designed RTC controller, the return angular velocity is designed to change as the steering wheel angle changes, making the steering wheel return to the center position accurately and smoothly. In addition, the proposed control strategy based on single neuron adaptive PID control can cope with the control parameter uncertainty in the process of RTC control. The experimental results demonstrate that the corrected active RTC control method compared with uncorrected one effectively reduces the residual angle of the steering wheel at low vehicle speed as well as improves the RTC performance of the vehicle which does not affect the basic assist characteristics.
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摘要 :
The active return of the steering wheel is playing a significant role in Electric Power Steering(EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity activ...
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The active return of the steering wheel is playing a significant role in Electric Power Steering(EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity active return-to-center(RTC) control strategy based on single neuron adaptive PID control is proposed in the paper. In the newly-designed RTC controller, the return angular velocity is designed to change as the steering wheel angle changes, making the steering wheel return to the center position accurately and smoothly. In addition, the proposed control strategy based on single neuron adaptive PID control can cope with the control parameter uncertainty in the process of RTC control. The experimental results demonstrate that the corrected active RTC control method compared with uncorrected one effectively reduces the residual angle of the steering wheel at low vehicle speed as well as improves the RTC performance of the vehicle which does not affect the basic assist characteristics.
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摘要 :
The active return of the steering wheel is playing a significant role in Electric Power Steering (EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity acti...
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The active return of the steering wheel is playing a significant role in Electric Power Steering (EPS) system. In order to have a safe driving experience and comfortable maneuverability when cornering, a smooth angle velocity active return-to-center (RTC) control strategy based on single neuron adaptive PID control is proposed in the paper. In the newly-designed RTC controller, the return angular velocity is designed to change as the steering wheel angle changes, making the steering wheel return to the center position accurately and smoothly. In addition, the proposed control strategy based on single neuron adaptive PID control can cope with the control parameter uncertainty in the process of RTC control. The experimental results demonstrate that the corrected active RTC control method compared with uncorrected one effectively reduces the residual angle of the steering wheel at low vehicle speed as well as improves the RTC performance of the vehicle which does not affect the basic assist characteristics.
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The model of speed sensor-less vector control system of induction motors has been built on the AMEsim and Matlab/Simulink platform, AMEsim and Simulink can be connected by creating an S-function interface. The results of Co-simula...
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The model of speed sensor-less vector control system of induction motors has been built on the AMEsim and Matlab/Simulink platform, AMEsim and Simulink can be connected by creating an S-function interface. The results of Co-simulation indicate that the algorithms of model reference adaptive system (MRAS) based on counter electromotive force (EMF) can estimate the speed with some accuracy in static and dynamic conditions and make the electro-hydraulic power steering (EHPS) system offer the assist force as quickly as the sensor-based system. So the proposed model and control algorithms are correct and have reached the expectation.
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