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The wind speed forecasting is one of the key technologies in the operation of wind power plants and micro grids. However, the wind speed prediction is extremely complex and difficult due to the wind speed fluctuation and coupled weather conditions. This paper presents a multiperiod wind speed forecast approach based on data mining technique, which is the multi-objective optimal extreme learning machine with the association rules (AR-MOELM). On one hand, in order to improve the performance and efficiency of the extreme learning machine (ELM), the number of the hidden layer nodes and the penalty factor are optimized through multi-objective particle swarm algorithm (MOPSO)and membership function. On the other hand, the association rules(AR)are adopted to extract the preferable combination of the meteorological factors into the input matrix of the ELM for each season. The evaluation of the AR-MOELM is depicted in the Python environment by ultra-short-term, short-term and medium-term prediction experiments based on real wind speed datasets. The research results reveal that the proposed method improves the multiperiod wind speed prediction accuracy and outperforms existing methods.

This paper presents a Lexicon-Corpus-based Unsupervised (LCU) Chinese word segmentation approach to improve the Chinese word segmentation result. Specifically, it combines advantages of lexicon-based approach and Corpus-based approach to identify out-of-vocabulary (OOV) words and guarantee segmentation consistency of the actual words in texts as well. In addition, a Forward Maximum Fixed-count Segmentation (FMFS) algorithm is developed to identify phrases in texts at first. Detailed rules and experiment results of LCU are presented, too. Compared with lexicon-based approach or corpus-based approach, LCU approach makes a great improvement in Chinese word segmentation, especially for identifying n-char words. And also, two evaluation indexes are proposed to describe the effectiveness in extracting phrases, one is segmentation rate (S), and the other is segmentation consistency degree (D).

The objective of this study was to evaluate the electrophysiologic characteristics of Crista terminalis (CT) and their implication in the pathogenesis of atrial tachycardia in rabbits. For this purpose, 27 New Zealand rabbits were used. Using standard glass microelectrode technique, cellular action potentials (APs) of CT and pectinate muscle (PM) were recorded in normal Tyrode’s perfusion and Tyrode’s perfusion with 4 μM isoproterenol. Longitudinal conduction velocity (V L) and transverse conduction velocity (V T) of CT were measured. As our data show, CT tissue had a trend of spontaneous phase IV depolarization. Conduction anisotropy (V L/V T) of CT was 4.53 ± 0.91. The duration of the AP of CT was longer than that of PM cells. APD20 and APD90 for CT were 28.1 ± 3.5 and 145.3 ± 7.1 ms; and for PM cells were 21.8 ± 4.1 and 125.3 ± 6.3 ms, respectively (all P values

This study was designed to investigate whether administration of digitalis could improve mechanical function of left atrial appendage (LAA) and left atrium prospectively in patients with atrial stunning. Fifty-four consecutive patients in whom atrial stunning was observed immediately after cardioversion of chronic atrial fibrillation (AF) were randomized into digitalis or control group for 1 week following cardioversion. Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were performed prior to, immediately following, 1 day after and 1 week after cardioversion to measure transmitral flow velocity and LAA flow velocity. Electrical cardioversion of AF elicited significantly slower left atrial appendage peak emptying velocity (LAA-PEV) and peak filling velocity (LAA-PFV) immediately following cardioversion in both groups. 1 day post cardioversion, there were no significant differences in transmitral E wave, A wave, E/A ratio, LAA-PEV, LAA-PFV or left atrial appendage ejection fraction (LAA-EF) between digitalis and control groups. 1 week post cardioversion, no significant differences were found in transmitral E wave, A wave, E/A ratio, LAA-PEV, LAA-PFV or LAA-EF between the two groups. The occurrence rates of spontaneous echo contrast were not significantly different between digitalis and control groups one day and one week post cardioversion. In conclusion, digitalis did not improve left atrial and appendage mechanical dysfunction following cardioversion of chronic AF. Digitalis did not prevent the development of spontaneous echo contrast in left atrial chamber and appendage. This may be due to the fact that digitalis aggravates intracellular calcium overload induced by chronic AF and has a negative effect on ventricular rate.

For the harmonics measurement in the micro grid accurately a detection method based on continuous Morlet wavelet transform is proposed in this paper. Combined with the high resolution in the frequency domain of continuous wavelet transform, the Morlet wavelet function is used to extract the local maxima lines in each frequency band. The relevance of the local maxima lines and harmonic frequency is used to separate the harmonics orders clearly. In order to figure out the harmonics source in the micro grid, the modulation process of the voltage source converter, which is usually adopted in grid connected applications, is analyzed in detail. Because of the switching impact of the converter, even small harmonic magnitudes can excite harmonics of large magnitudes or cause additional harmonics. To overcome the disadvantage of the L-filter, the LCL-filter with virtual resistor is designed to eliminate the harmonics. Filter capacitor voltage feedforward with virtual resistor is inner fast loop, while outer loop with appropriate grid side current ensures fast command tracking. The use of the virtual resistor alleviates the impact of filter resonance on the specific frequency and improves the system stability. This paper with theoretical and simulation results, demonstrates effectiveness of the purposed methods to detect and eliminate the grid side harmonics in the micro grid.

Hybrid energy storage can take advantage of super capacitor's high power density and battery's high energy density. At the same time, hybrid energy storage cost less. So it's suitable for micro-grid power balance control. This paper presents a main circuit structure which is Buck/Boost converters connecting super capacitor and battery with PWM (pulse width modulation) inverter to achieve bi-directional power adjustment and improve utilization of super capacitor. DC bus voltage is sensitive to and fluctuates with switching of PWM inverter's working conditions. To solve this problem a combination of voltage-current close loop control and power feed-forward control is adopted in super capacitor control while achieving fast power tracking; peak current control is adopted in battery control, this control strategy has simple control circuit and high reliability. Meanwhile peak current control can limit maximum current of battery, so it can protect battery and prolong battery life. Simulation confirmed the effectiveness of the method with voltage fluctuations within the range of 10%.

Due to the nonlinear load and transient power grid failure (such as phase jumps, voltage sags and swells, frequency changes, harmonic pollutions), three-phase voltage is asymmetry and in distortion state. In this case, grid-side converter control system will lose control of the power signal, causing protection system tripping or damaged. Thus, we need to design a control strategy to ensure reliable and safe operation under abnormal power grid condition, which can help to low voltage ride through and grid voltage frequency support. This paper designed the current control system containing unbalanced algorithm. On the basis of the traditional dq control, this paper added the negative sequence current compensation part and solved the oscillation problem of injected active power and reactive power. This paper also presented a design method of PI regulator in current control loop. The new controller needs to deal with positive and negative sequence components respectively, so we designed the double second-order generalized integrator phase-locked loop (DSOGI-SPLL). The small signal model of phase-locked loop and the parameter setting method were given. In the end, we compared the old and new methods on the performance in balanced and imbalanced power grid. It was proved that the new control strategy can meet the target.

High voltage insulating bushing is an important component of GIS of the high potential and ground potential insulation. The even electric field distribution and reasonable structure of bushing will guarantee the safe operation of GIS. In order to solve the problem of structural design and electric field distribution of 126 (kV) GIS bushing, a mathematical model to calculate the electric field distribution of high voltage insulating bushing was established in this study, and numerical simulation and visualization processing for electric field distribution of bushing was made by ANSYS. Furthermore, the insulation size was determined and verified. Consequently, the numerical foundation of insulation structural design and the development of 126 (kV) GIS bushing are provided.

A novel automatic seeded region growing method (SRG) for high temperature region extraction of IR image is proposed in this paper. The proposed method efficiently utilizes the RGB values of IR image. The neighborhood average method is selected to reduce image noise. Red component and green component which are more efficient to extract high temperature region because their values are positive correlated with temperature, are extracted to make segmentation using seeded region growing method. Seed points are determined as the connected pixels which exceed a certain threshold, and the grow criteria is based on the gradient of the two component images. Intersection method is used for image fusion, and high temperature region is extracted. Experiment results indicate that the method can accurately recognize the high temperature area, and the outline is clear.

The insulation of apparatus in the power system is often broken by the very fast transient over voltage (VFTO), which cause from the operation of disconnector in gas insulate substation (GIS). In this paper, a new idea for the Suppressing VFTO by ferrite is put forward, and the characteristic of ferrite is analyzed. The effect of suppressing VFTO by the ferrite is tested. Methods to estimate the size of ferrite are advanced, and the characters of the two calculating methods between constant magnetic conductivity and constant frequency for the size of ferrite are discussed.

Power transmission voltage is higher than the rated voltage according to the standard, in order to avoid the voltage drop because of the power loss and the overload. However when the load in the power network is light, the excessively high electrical network voltage may cause the load equipment to give off heat, and reduce service life. At the same time the power consumption and electrical bill disbursement increase. So adjusting the voltage for steady power supply and saving power is an important content of improving electrical network performance, ensuring power supply quality, and reducing waste. The basic structure and principle of saturable controllable reactor is studied in this paper. To adjust and stabilize the voltage of power system by a new type saturable controllable reactor is advanced. According to the characteristic of loads, the voltage is adjusted to stabilize the power supply and saving power.

An adaptive algorithm for real-time channel estimation is proposed, which is a blind estimation of signal-to-interference ratio and signal-to-noise ratio. It works well in the case of multiple interferences and noise by using an improved adaptive k-NN technique. The channel in wireless security communications, such as adaptive frequency hopping (AFH), would be taken as an example to show the validity of the proposed algorithm. The algorithm is particularly effective in the case of noise-free signal disturbed by interferences of the known type. In our discussion, the signal is /spl pi//4 DQPSK, and the interferences and noise are GFSK, CW, and AWGN. The reason why we assume the interferences and noise are GFSK, CW and AWGN is discussed in the full paper. When the signal or interferences are of the other types, the estimator given in the full paper also brings good results. The algorithm has been implemented on the platform based on ADSP21160, and it works well.

The insulation of apparatus in the power system is often broken by the very fast transient over voltage (VFTO), which cause from the operation of disconnector in gas insulate substation (GIS). In this paper, a new idea for the suppressing VFTO by ferrite is put forward, and the characteristic of ferrite is analyzed. The effect of suppressing VFTO by the ferrite is tested and simulated. The particular request of the ferrite parameters is discussed. A method for the estimating the size of ferrite is advanced.

Electronic combination sensor for current and voltage has advantage at frequency response width, performance steady, high reliability, small size, light weight, and easy connect for net of power system. It has application in the measure and protect of power system. The important technology development of the sensor is the design of electronic circuit. In this paper, a new plan of the electronic circuit sensor is put forward, and is integrated with the current and voltage detect, over current protect. The circuit include with over voltage protect, signal processing, isolation amplifier circuit, integral phase-shifting etc module.

The paper suggests a kind of packet protocol for frequency-hopping networks based on chaotic non-periodic frequency-hopping (FH) sequences. The packet error and throughput performance of a frequency-hopping multi-access (FHMA) network are derived theoretically. It is shown that the ratio of the packet length to the frequency-hopping points is the key parameter to determining the FHMA system performance under the condition of a large number of users. Computer simulation results of the logistic chaotic sequences are also included to support our development.

Two kinds of temperature transducers and several data process algorithms are researched in this paper in order to realize online temperature monitoring in insulation material for HV devices. And their sensibility is compared; assembler programming is also realized. The results of simulation test proved that the selected temperature transducer and data processing method has higher sensibility better stability and higher accuracy. So this device has the value of engineering application.

The measurement includes the UHF detection, conventional partial discharges (PD) measurement and the power phase analysis. The corona discharge characteristic of model GIS is researched. Then discharge level of UHF signal is estimated based on comparing of UHF detection and the conventional PD measurement.

Objectives To evaluate the effects of ACE inhibitor and angiotensin receptor blocker on serum sex hormones, gonado-somatic index (GSI) and erection function in spontaneously hypertensive rats (SHRs). Methods 24 SHRs were distributed initially in three groups: Valsartan group (n=8) received valsartan (30 mg/kg/day) and Benazapril group (n=8) received benazapril (10 mg/kg/day) dissolved in 0.5 ml distilled water, the Control group (n=8) received only distilled water (0.5 ml/day). Then 8 Wistar-Kyoto rats (WKYs) (WKY group) were treated with the same as Control group. Body weight, systolic blood pressure (SBP) and sex hormones were measured at baseline and after treatment in all rats. The intracavernous pressure (ICP) and mean arterial pressure (MAP) were measured at the end of treatment course. Then the rats were sacrificed by carotid artery bloodletting, serum was stored to measure sex hormones by electro chemiluminescence assay. The testicles were removed for measuring testicular weight quickly. Results Both valsartan and benazapril reduced the SBP after treatment with 2 months, but serum testosterone and oestradiol weren9t reduced. As compared with Valsartan and Benazapril group, the testosterone of Control group was reduced and the oestradiol was increased (p 0.05) at 0, 2, 5 V of electrostimulation, respectively. No significant difference of testicle weight and GSI were found in all the groups (p>0.05). Conclusions The serum testosterone was reduced and the oestradiol was increased in the control SHRs, which harm to the erectile function. Erectile dysfunction in SHRs may be due to oestradiol-testosterone imbalance.