Advanced Materials Research Vols. 383-390

Abstract: In order to evaluate pilot performance objectively, back propagation (BP) neural network model of 621423 form in topology with eye movement data was established. Data source of BP neural networks that came from former experiment and random interpolation was divided into training set and test set and normalized. Based on neural networks toolbox in Matlab, hidden layer nodes of BP networks were determined with empirical formula and experimental comparison ; BP algorithms in the toolbox were optimized; The training set data and test data were input into model for training and simulation; Pilot performance of the three skill levels was predicated and evaluated. The research shows that pilot performance can be accurately evaluated by setting up BP neural networks model with eye movement data and the evaluation method can provide a reference for flight training.

Abstract: This paper describes the self-cleaning filter structure, working principal and the main parameters, and it describes the hardware, control theory and software design process. Pressure transmission control method, time control, automatically open and close cleaning and sewage systems are used in automatic self-cleaning filter, which fully realizes unmanned operation, stable and reliable. There are some reference values in this article for the depth understanding of design and development the automatic cleaning filters.

Abstract: Objective To study expert and novice eye movement pattern during simulated landing flight for providing references to evaluate flight performance and training of pilots. Methods The subjects were divided in to two group s of expert and novice according to their flight simulation experience. Eye movement data were recorded when they were performing landing task. Comparison of expert and novice flight performance data and eye movement data was made. Results It was found that the differences between expert and novice lay not only in flight performance but also in eye movement pattern. Performance of expert was better than novice. Expert had shorter fixation time, more fixation points, faster scan velocity, greater scan frequency and wider scan area than novice. It was also found that eye movement pattern of expert bring lower mental workload than novice. Conclusion Flight performance is related to eye movement pattern. Effective eye movement pattern is related to good flight performance. The analysis of eye movement indices can evaluate pilots’ flight performance and provide reference for flight training.

Abstract: Taking advantage of improving voltage stability L indicator, voltage level, active power loss to assess device reactive capability in overload situations. Considering the intermediate buses which connect the generator bus and load bus, the compound buses which involve the two types of buses, improving voltage stability L indicator is proposed. So device reactive capability could be calculated. The example shows the best reactive device is generator, and the second one is capacitor bank and the last one is transformer tap. Assessment of reactive device capability is beneficial and practical for operation stuff to take appropriate measures in order to transfer overload situations into normal state.

Abstract: The Non-uniform rational B-spline (NURBS) is widely used in CAD/CAM/CNC. The NURBS interpolation is crucial for an advanced CNC system compatible with NURBS. Classic NURBS interpolation algorithms always do not well consider both the contour precision and feedrate smoothness. This paper proposes a NURBS interpolation algorithm based on the feedrate sensitive points identification. The feedrate sensitive points is found out according to the chord error which is relative to the feedrate passing this point. Furthermore, the feedrate profile is adaptively planned between two adjacent sensitive points according to the distance between them. The feedrate profile of the whole NURBS can be connected with these feedrate sections. A cubic NURBS curve is adopted to evaluate the interpolation algorithm. Simulation results show that the proposed interpolation algorithm is available with reference value for industrial application.

Abstract: ARL (Average Run Length) is used as a tool to measure the performance of control chart. But it isn’t very accurate. In this paper, a Markov chain method is proposed to calculate the APL (Average Product Length) of EWMA chart, and APL is used as a criterion of performance assessment to decide optimal design of this chart. By comparing with traditional EWMA design method, we can find that this method can detect little shifts in processes more quickly.

Abstract: Based on finite element simulation, the temperature field model for the frictional pair of third rail and collector shoe under the coupling of contact resistor thermal and friction thermal was established. The method of coupling the two kinds of thermal was given in detail, the temperature field was calculated, and the maximum coupled temperature changing under different electric current, velocity, and displacement of the model was studied. The results show that the temperature raising effect of friction thermal and contact resistor thermal is different. In the process of mechanical friction without electric current, the highest temperature is in the contact center line, the temperature distribution expands around the contact zone in descending tendency. But in couple condition, the temperature distribution with electric current expands around the contact point in descending tendency. In the two conditions, the temperature gradients are all becoming smaller. The maximum coupled temperature increases with the increasing of the electric current, and decreases with the increasing of the velocity under the constant displacement and normal force. The maximum coupled temperature increases linearly with the increasing of displacement under constant electric current, velocity and normal force.

Abstract: An efficient domain decomposition method (DDM) is employed to improve upon the efficiency and capability of the finite element-boundary integral (FE-BI) method for calculation of electromagnetic (EM) scattering from deep cavities. This method first subdivides the original cavity into many sub-domains along its depth and classifies these sub-domains into a few building blocks. It then employs the substructuring method to deal with the different types of sub-domains. The resulting Schur complement system is solved by a special method which has low memory requirements because the formation of the global Schur complement matrix is not necessary. Numerical results indicate that the presented method is an effective approach for scattering by deep cavities.

Abstract: A MPPT (Maximum Power Point Tracking) control method of PV (Photovoltaic) generation system is proposed based on the shortcoming of the existing MPPT algorithms. The method applies CVT (Constant Voltage Tracking) algorithm to adjust the working point of PV array near the MPP (Maximum Power Point) for fast tracking when working point is far from MPP, and uses adapting duty cycle perturb method to optimize the steady state characteristic of MPP for effectively eliminate the output power oscillation under the setting precision. Its model is established and simulated with Matlab/Simulink.The CVT, duty cycle method and proposed methods are simulated respectively and simulation results show that, the proposed method tracks the MPP exactly and quickly and improves the energy conversion efficiency of PV generation system by eliminate the output power oscillation around MPP. Its fast response speed improves the static and dynamic performance of photovoltaic power system.

Abstract: Islanding detection is a absolutely necessary function for Photovoltaic Grid-Connected Inverters and it is very important to detect the islanding accurately and quickly with less adverse impact on power quality. This paper proposes a positive feedback intermittent active frequency drift method which can decrease the adverse impact of frequency disturbance effectively within the time restrict of islanding detection according to that of traditional islanding detection methods. The theoretical analysis and simulation results show that this algorithm which is simple, effective, fast and have less adverse impact on power quality and has certain application value.