With the expending scale of the power grid and the substantial development of renewable energy generation system, the demand for power quality is becoming more and more significant. The doubly fed pumped storage can b...
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The visual background extraction algorithm (ViBe) uses the first frame of the video as the initial frame to initialize the background model. If the initial frame of the background model has a moving object or the stat...
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The visual background extraction algorithm (ViBe) uses the first frame of the video as the initial frame to initialize the background model. If the initial frame of the background model has a moving object or the state of the moving object changes (from still to motion or from motion to still) or the update rate of the background model is not synchronized with the background variability, there will be false target which is known as ghost. Aiming at this problem, a discriminant method based on histogram similarity measure of foreground region and neighborhood background region is proposed. The algorithm can detect ghost regions from the moving area. The experimental results show that compared with the traditional algorithm, the improved algorithm can effectively remove the ghost of foreground detection, and the detection of the object is more accurate.
With the continuous development of the Internet and information technology, data has penetrated into every area of today's industry and business functions. Now, data has been already one of the most valuable asset...
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With the continuous development of the Internet and information technology, data has penetrated into every area of today's industry and business functions. Now, data has been already one of the most valuable assets in the Internet and a core element of a company's competitiveness. There seems to have endless data on the Internet, then most of it cannot create value. When we face data mining, wo need to complete a lot of data cleaning tasks. Nowadays, the rapid development of machine learning, especially the deep of learning, has made excellent achievements in natural language processing and image recognition. The paper combines multiple strong learning machine to complete the data learning tasks and image recognition based on ensemble learning, thereby reduce the pressure on the server storage and investment of resource.
Aiming at the instability of traditional color feature tracking algorithm in some complex scenes, an object tracking algorithm with integrating color and contour features is proposed. The algorithm still uses the trad...
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Aiming at the instability of traditional color feature tracking algorithm in some complex scenes, an object tracking algorithm with integrating color and contour features is proposed. The algorithm still uses the traditional particle filter to predict the target, but in iteration every time, when searching the best position of the target, the color and contour information of the target can be adaptively combined. Experiments show that it shows good effectiveness and robustness compared with the traditional algorithms when the target is interfered between similar colors or the target is partially obscured.
Power electronics based load equipment has now more and more used in power grid these years. Their frequency characteristic is worthy of study in detail for it is very different from that of traditional load equipment...
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ISBN:
(纸本)9781538604915
Power electronics based load equipment has now more and more used in power grid these years. Their frequency characteristic is worthy of study in detail for it is very different from that of traditional load equipment, and the regular load model may not be suitable such as in the security and stability analysis of modern power system. Firstly, so much these new-type load equipment are classified in several typical categories. Then, response curves are obtained from physical experiment. Thereafter, the static frequency characteristic of new-type loads is discussed and the trend of parameters is predicted. Finally, compared with the recording curves of a real bulk power grid during large frequency disturbs, the change of parameter is verified and the potential impact on power grid is analyzed.
Distribution network with a large number of distributed generators(DG)puts forward higher requirements for coordinated control of voltage and reactive *** coordinated voltage control is an effective method to improve ...
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Distribution network with a large number of distributed generators(DG)puts forward higher requirements for coordinated control of voltage and reactive *** coordinated voltage control is an effective method to improve distribution network voltage level under the condition of high permeable *** on the basic principle of the secondary coordinated voltage control,multi-objective linear programming method is used to solve the contradiction between the safety and the economy of the distribution network,and the optimization goal construction,control strategy selection and control process realization are introduced *** simulation results show that the secondary coordinated voltage control based on multi-objective programming can be used to solve distributed network voltage stability,but also can improve the efficiency of ADN.
In order to overcome the Excessive time complexity of bad quality when the disposing the picture whose foreground is similar to background of grabcut method, a grabcut method based on superpixel is proposed in this pa...
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In order to overcome the Excessive time complexity of bad quality when the disposing the picture whose foreground is similar to background of grabcut method, a grabcut method based on superpixel is proposed in this paper. This method, firstly, extracting the superpixel block of the picture. And then, split the picture which is extracted. The experimental results show that this method is effective to improve the speed of segmentation. What's more, this method can solve the problem of bad quality when the disposing the image whose foreground is similar to background in a certain extent. This paper has certain advantage in disposing those image whose size are too big and foreground is similar to background.
With the rapid development of renewable energy power generations,AC/DC transmissions and static compensations etc,power electronic technology has been widely applied in power *** traditional power equipment is replace...
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With the rapid development of renewable energy power generations,AC/DC transmissions and static compensations etc,power electronic technology has been widely applied in power *** traditional power equipment is replaced by a large number of power electronic devices,the disturbances such as harmonic interference and sub-synchronous oscillation are more *** order to detect the sub synchronous oscillation in power system in time,and take measures to ensure the safety and stability of power system,this article analyses the algorithm principle of the PMU and the communication architecture of WAMS/PMU *** to the IEEE Std C37.118-2011 standard,it elaborates the problems and the limitations existing in the monitoring of sub-synchronous and super-synchronous harmonic parameters on *** the basis of the above,a method of on-line identification and alarm for the sub-synchronous and super-synchronous harmonic parameters on PMU device is *** with FFT spectrum correction theory,the high accuracy identification method of distributed sub synchronous and super synchronous harmonic parameter is *** feasibility and accuracy of the method is verified by simulation experiments.
An ultra-short-term wind speed forecasting method based on spatial and temporal correlation models is proposed. Firstly, the temporal correlation model was studied. The generalised distance of wind speed time series i...
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An ultra-short-term wind speed forecasting method based on spatial and temporal correlation models is proposed. Firstly, the temporal correlation model was studied. The generalised distance of wind speed time series is defined based on the dynamic time warping distance and correlation coefficient. Samples with similar wind dynamic patterns are classed into the same group. Time series in one group are depicted with a representative time series which is modelled by an autoregressive moving average (ARMA) model. For time series which cannot be classed to any of these groups, a special group was defined. It was modelled by artificial neural network (ANN). Secondly, the spatial correlation between the target wind farm and the reference wind farm was investigated with the meteorological data taking into consideration. The grey prediction method is utilised to predict the wind speed. Finally, the combined ultra-short-term wind speed forecasting method is proposed. It takes into account the inherent time correlation of the target wind speed and its spatial correlation with reference wind farm. The wind speed prediction of wind farms in northwest USA verifies the effectiveness and feasibility of the proposed method.
Power system security and stability control is heavily dependent on the reliability of communication network. The communication interruption and latency may cause security and stability issues in power system. Thus, s...
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ISBN:
(纸本)9781538622131;9781538622124
Power system security and stability control is heavily dependent on the reliability of communication network. The communication interruption and latency may cause security and stability issues in power system. Thus, studying the dynamic procedure of the interaction between power system and communication network in fault situation becomes more and more important. In this paper, by analyzing the weakness of the existing co-simulation frameworks, a new co-simulation framework, Global Status Event-Based Iterative Co-simulation Framework, is proposed, in which a global event scheduler manages the communication simulator and power simulator, and power simulator will run iterative simulation as a new event is identified and added to the global event scheduler. Then, a co-simulation platform based on the proposed framework is introduced which integrates the power system simulator and communication network simulator. Finally, a case is studied and reveals the procedure of the cascading failures in both power system and communication network, which cannot be captured by the simulation of a single system.
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