Advanced Materials Research Vols. 403-408

Abstract: GM-GARCH model is a new hybrid volatility model which integrates grey forecasting model (GM (1,1)) into GARCH model. As for the limitation of the parameters estimation algorithm of GM (1,1) model, a SVRGM-GARCH model is established to enhance volatility forecasting performance further. Firstly, support vector machines for regression (SVR) is utilized to estimate the parameters of GM (1,1) model (SVRGM). Then, the SVRGM model is used to modify the random error term sequence of GARCH model. An empirical research is performed on SSE Fund Index and SZSE Fund Index. The result shows that the SVRGM-GARCH model outperforms the GM-GARCH models and GARCH model, which indicates the model proposed in this study is an effective method for volatility forecasting.

Abstract: This paper reports design, modeling and simulation of MEMS based sensor working in dynamic mode with fully differential piezoresistive sensing for monitoring the concentration of exhaled carbon dioxide (CO2) gas in human breath called capnometer. CO2 being a very important biomarker, it is desirable to extend the scope of its monitoring beyond clinical use to home and ambulatory services. Currently the scope of capnometers and its adaption is limited by high cost, large size and high power consumption of conventional capnometers . In recent years, MEMS based micro resonant sensors have received considerable attention due to their potential as a platform for the development of many novel physical, chemical, and biological sensors with small size, low cost and low power requirements. The sensor is designed using 0.35 micron CMOS technology. CoventorWare and MATLAB have been used as simulation software. According to the developed model and simulation results the resonator has resonant frequency 57393 Hz and mass sensitivity of 3.2 Hz/ng. The results show that the longitudinal relative change of resistance is 0.24%/µm while the transverse relative change of resistance is -0.03%/µm.

Abstract: According to main challenges to aircraft protection against high power microwave (HPM), the formula of electromagnetic transmission rate and reflectivity both for the perpendicularly and parallely polarized incident field are modified and simplified, a shielded cockpit glass construction is designed by a new optimized method on genetic algorithm, and protective efficiency analysis on military aircraft’s cockpit against HPM is carried out on a virtual 3D plane, airborne equipments and pilot model with a scale of 1:1. The verification simulation tests show the optimized construction has good protective efficiency in the range of carrier frequencies between 1-20 GHz, and protective intensity does not exceed limits of relevant international standard.

Abstract: A body finite difference time domain (FDTD) grid modeling engineering method and a simplified parallel FDTD algorithm are brought forward based on frequency-dependence electromagnetic equation by nonparametric curve fitting. By a shielded construction designed soft kill analysis against high power microwave (HPM) is carried out respectively on 3D simple and digital pilot in fighter model with a scale of 1:1, which is electrically huge and very complex in geometry and electromagnetic characteristics. The simulation tests show that the protective effectiveness to soft kill is good with shielded construction at 0.3-6GHz, HPM protective efficiency evaluation on digital pilot model is more optimistic and complex than that on simple pilot model, and speedup ratio of the presented approach can compare with that of the conventional method.

Abstract: Requirement of voltage up-converters due to high pull-in voltage is one of the main problems by merely electrostatic actuated Microelectromechanical system-based switches. Thermally actuated switches are another alternatives but with very high power dissipation. In this paper a low voltage switch is demonstrated, which uses a combined thermo-electrostatic actuator. The switch can be integrated with standard CMOS circuits without any up-converters. Thermally power dissipation for the switch is lower than just thermal actuators. The switching time is about 70µs and the maximal temperature of thermal actuator is lower than 150oC which cannot cause any longtime damage. Isolation and Insertion Loss quantities have been calculated to -25dB and -0.65dB at 20GHz from HFSS results respectively.

Abstract: Based on the most prosperous System on Chip (SOC) in the field of microelectronics, the open and real-time robot controller was analyzed, the application and development platform was built. By means of representative evaluation index, cohesion and coupling, the modularized design and the open architecture of robot controller were implemented. It is proved that the average distance between the same modules is short, and therefore the system is better cohesive. And the average distance between different modules is long, and therefore less coupled. Consequently, the whole system is excellent in openness. At the same time, the real-time schedule of controller tasks is analyzed from theory and experiment. It is proved that the controller based on SOC is excellent in real-time performance. The experiment showed that SOC-based robot controller is highly modularized, the parameters is clear, the architecture is easily implemented and revised, and therefore is adaptive to different controlling requirement and module building.

Abstract: Nonparametric models of hydraulic damper based on support vector regression (SVR) are developed. Then these models are compared with two kinds neural network models. One is backpropagation neural network (BPNN) model; another is radial basis function neural network (RBFNN) model. Comparisons are carried out both on virtual damper and actual damper. The force-velocity relation of a virtual damper is obtained based on a rheological model. Then these data are used to identify the characteristics of the virtual damper. The dynamometer measurements of an actual displacement-dependent damper are obtained by experiment. And these data are used to identify the characteristics of this actual damper. The comparisons show that BPNN model is best at identifying the characteristics of the virtual damper, but SVR model is best at identifying the characteristics of the actual damper. The reason is that all experimental data include noise more or less. When the amplitude of the noise is smaller than the parameter of SVR, the noise can not affect the construction of the resulting model. So when training a model based on the experimental data, SVR is superior to other neural networks methods.

Abstract: This paper is concerned with the problem of robust stability and stabilization of singular systems with uncertainties in both the derivative and state matrices. By using a parameter dependent Lyapunov function, we derive the LMI-based sufficient conditions for the stabilization of the singular systems. Secondly, by solving these LMIs, a proportional plus derivative (PD) state feedback controller is designed for the closed-loop systems to be quadratically normal and quadratically stable (QNQS). Finally, the numerical example is given to show the effectiveness of the proposed theorems.

Abstract: This paper presents an approach to modeling aircraft airline maintenance circuit through a particular Petri Nets structures, called Treble transitions Petri Nets. In order to meet the requirements of the simulation of aircraft airline maintenance circuit, several enhancements were proposed. The first of them consider the characteristic of circuit, the places, transitions and arcs of classical Petri Nets are extended. In the Second enhancement, the rules of transitions were modified. Finally, the relating matrix and the state transfer equation are redefined. One case is included illustrating the applicability and efficiency of the proposed modeling method.

Abstract: This paper presents the accident type of mining trucks, then gives the reasons of the problem by analyzing the structure characteristics and work environment of the trucks, and points out that the large blind area around the mining trucks is the main reason of frequent accidents. In order to monitor the blind area roundly and efficiently, the paper proposed a design scheme of safety monitoring alarm system using CAN bus technology, PLC technology and radar monitoring warning technology, which can assist driver to monitoring the blind area efficiently. The paper also gives a detailed description of the system designing and installation on mining trucks. It's concluded that the safety monitoring alarm system have a good performance to avoiding the blink area and a good application prospect, the system can be widely used on mining trucks.