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In the traditional direct torque control (DTC) of induction motor, the low order harmonic component of stator current is very large when the motor is running at low speed. It leads to high torque ripple of motor in low speed. To solve this problem, a new control method has been proposed in this paper. Base on the traditional DTC method, electromagnetic torque and flux models have been analyzed. To...
This paper presents the study on data organization and structure in spatial database designs. An object-oriented spatial database model is developed for coalfield geological hazards taking into account the unique characteristics of coalfield geological hazard data structure. The model is successfully applied to the construction of a spatial database of coalfield geological hazards with Unified Modeling...
The improper use of exception handling mechanism will affect the efficiency of the application development in programming, so this paper analyzed and summarized several exception fault types for the exception fault problem of AspectJ, and gave the corresponding examples to analyze the impact of exception fault on program control flow, so that the developers can better avoid or deal with these exception...
Traveling Salesman Problem (TSP) is a typical combination optimization problem; it is hard to find a precision result. So it is very important to search for the near result.
The GT-POWER software was used to build the working process model of the diesel engine; through the bench test of the diesel engine, the simulation results were contrasted with the test results to proof the accuracy. The advance angle of injection of diesel engine was optimized at different loads of 2200r/min 1500r/min, the major parameters regularity of the diesel engine was further studied and the...
The Pile Extractor of water jetting is one kind of the new developed products and the 3-D modeling and the assembly of its various spare parts were carried by 3DSMAX.The water jetting was simulated by using the granule system. The reasonable structure and the best effect of water jetting flow were attained through the 3-D virtual design and the flow simulation. The machine was made based on the virtual...
In this paper, high performance real-time detecting and tracking technology for news events are proposed. The difference to previous TDT articles in the detection and tracking is that this attempt to establish the historical hotspot events Corpus first, and analyze the characteristics of the corpus according to timeline. HMM-based named entity recognition model is also used to find out other event...
On the stochastic models of economic optimization of Prof. Chen M F, this paper chooses Prescott's paradigm to analyze how optimally to allocate the investment of Jiangsu Province to coordinate the comovements of Jiangsu's transportation and non-transportation, acquires a optimal stochastic controllable model for the coordinated developing, finds a worthy Euler equation of this model, does a numerical...
The feature extraction is one of the key steps for SAR ATR. It can greatly reduce the amount of information processing by SAR ATR, improve the identification efficiency, reduce the time of recognition and lower resources utilization by means of the feature extraction. In the beginning, the feature extraction methods are classified by target type and then various categories methods are summarized....
Energy is limited for the nodes in wireless ad hoc networks, which is a key factor to influence the lifetime of the networks. Employing energy conservation routing strategies, for instance, can be an effective way to prolong the lifetime of the networks. In this paper, an improved AODV routing strategy is proposed by creating backup node for next hop during the route discovery phase. Whenever the...
Local anodic oxidation with atomic force microscopy has became a major technique for nanofabrication. Finding a proper and efficient way to assemble the discrete dots or lines into one uniform layer with specific shape is critical for application. The aim of this paper is to find a more flexible way to analyze and guide LAO procedure. The threshold pitch for assembling a uniform line is further studied...
A 3D flow numerical investigation was performed to explore the effects of spraying angel, structure type and rotation on the combustion property of liquid propellant in combustor AUV. The combustion flow field was simulated using κ - ε turbulence model for gas turbulent, Eddy Dissipation model for gas combustion, six-flux radiation model and particle tracking model for liquid. By Fluent software,...
Data sets resulting from metabonomics or metabolic profiling experiments are becoming increasingly complex, which is hard to summarize and visualize without appropriate tools. The use of chemometric tools, such as orthogonal signal correction (OSC), principal component analysis (PCA), partial least squares to latent structure discriminant analysis (PLS-DA), make the data dimensionality reduction and...
Data sets resulting from metabonomics or metabolic profiling experiments are becoming increasingly complex, which is hard to summarize and virsualize without appropriate tools. The use of chemometric tools, such as OSC, PCA, PLS-DA, OPLS-DA make the data dimension and interpretation much easier. Here we showed a system method based on PCA, OSC-PLS-DA for metabonomic data analysis; Furthermore, S-plot,...
In this paper, a multi-sensor data fusion algorithm was put forward. First, based on the statistics, the standard deviation relating to the fusion value of sensors' measured data was used to estimate sensor's variance. Secondly, by using this estimate variance, a new adaptive weighted fusion algorithm for multi-sensor data fusion, as well as its iterative form, was put forward. Then, a “memory attenuation...
A modified LPV (Linear Parameter Varying) modeling method for nonlinear system was put forward and is applied in modeling a turbofan engine system. First, a quasi-LPV model of a turbofan engine is designed at various engine operating points using linearized models of the engine dynamics and the scheduling variable is the low-pressure compressor speed. Then, according to the feedback method, the quasi-LPV...
In this paper, on the basis of AHP and the comparative pricing in the current market value method, a software pricing evaluation model is introduced reference the existing software price evaluation method. Based on this model, we analyze the existing open-source software profit model and give the evaluation criteria for value evaluation and finally introduce the evaluation of open-source software...
This paper proposes a algorithm of maximum power point tracking based on fuzzy Neural Networks for photovoltaic generation systems. The system is composed of a boost converter and DC pump motor load. The maximum power point tracking control is based on fuzzy Neural Networks to control a IGBT switch duty ratio of a boost converter. The fuzzy Neural Networks provide attractive features such as fast...
Because of the complexity and randomness of the gas-solid two-phase flow, it is still hard to fully understand the dynamic behavior of the flow. The electrostatic signal contains rich information of the particulate flow. Multiscale entropy (MSE) analysis of electrostatic fluctuation signal was conducted in this paper. The electrostatic signals were obtained from the horizontal pipeline in dilute pneumatic...
Roll eccentricity is one of the most important factors that affect the quality of the steel plate and strip products. In this paper, Mill eccentric model is established and analyzed. New idea that is proposed that roll eccentricity disturbance on gauge is chaotic during rolling. Fuzzy controller is used to control the chaotic system. A new variable universe fuzzy controller based on improved ant colony...
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