Advanced Materials Research Vols. 490-495

Abstract: Spectrum trading is an important approach for the secondary users (SU, the unlicensed user) to share the spectrum resource with the primary users (PU, the licensed user). Such economic method can improve not only the efficiency but also the quality of spectrum sharing. For getting the most profit from the spectrum trading, we considered a spectrum trading model based on queueing theory. We analyzed the relationship between the spectrum server and the spectrum demander and discussed the problem of server uncertainty. Simulation results demonstrated the analysis results in terms of the idle probability and average queue size.

Abstract: Contrary to the problem that automobile switches have various kinds and large differences in the structure and performance so that traditional testing methods have been unable to meet the testing requirements of high performance switches, the paper designs a new detection system used to detect the functions of general auto switches which applies the developing environment LabVIEW based on virtual instrument technology and adopts the technology of embedded observe and control system. Using PC as the host computer, the system adopts the LabVIEW8.5 to compile a real-time monitoring system with good human-computer interface; S3C2440-ARM9 processor is used as the main controller of observe and control system in the inferior computer which collects output current signal when the circuit is conducted after switch is pressed. After the coding process of LwIP software protocol and the drive of Ethernet controller DM9000, the signal is transmitted to PC through Ethernet interface. Compared with conventional testing measures, this system greatly improves the real-time performance as well as working efficiency of detecting switch functions and reduces the corresponding human and material resources.

Abstract: Combining SVM and fractal theory, a novel fault diagnosis method for analog circuits based on SVM using fractal dimension is developed in this paper. Simulation results of diagnosing the Sallen-Key band pass filter circuit have confirmed that the proposed approach increases the fault diagnosis accuracy, thereby it may be considered as an alternative for the analog fault diagnosis.

Abstract: Dual-clutch automatic transmission with two clutches alternate way to achieve work uninterrupted power shift, showing the precise control of the clutch in the dual clutch automatic transmission is extremely important, From that point the text, the design of a converter based on AD7731 dual clutch automatic transmission pressure measurement system, the analysis in detail the system design and the corresponding interface circuit, the test results show that the pressure measurement system design can be very good to meet the needs of the clutch pressure measurement system

Abstract: This paper proposes a new algorithm for the detection of moving objects based on picture blocks and HVS color space of image differences techniques. The experimental results show that this algorithm can overcome the weakness of image background differencing and coterminous frame differencing method and suppress shadows effectively with advantages of self-adaptation and high speed. It can be used to detect the high-speed moving objects in the complex.

Abstract: In this paper, a vector control model based on MRAS with speed sensorless is established and observed the influence of parameters on the output waveform of speed and torque by changing the parameters of and in PI regulator of speed calculating module. Experimental results show that the precision of speed recognition is affected by the parameters and . It is verified that the optimal value of and in the model is when is 4400 and is 1.98.

Abstract: The concept of dynamic directional manipulability is taken as an evaluating index of jumping performance to quest for improvement of the jumping performance of the jumping robot in view of the mechanism design. On the basis of the jumping robot mechanism model, the dynamics equation in takeoff phase is established, and the mapping relation from the joint driving torque to the acceleration of the center of mass movement is obtained. In order to optimize the jumping performance of the robot, optimal algorithm combining with the dynamic directional measure is used to optimize the mechanism parameters of the jumping robot. The optimal result demonstrates that the research on mechanism parameters optimization of jumping robot is feasible by using the theory of the dynamic directional manipulability measure

Abstract: In this paper, the microcapsule of PCM (phase change material) was prepared, and the temperature adjustment principle of PCM was introduced. From the SEM, the morphology of microcapsule was shown as circle and uniform, which accorded with the particle distribution. The DSC curve showed the PCM heat change process. In this paper, the thermal transfer of microcapsule on the fabric was also introduced which was very useful for smart fabric application.

Abstract: Due to alternating work mode of twin-cylinder of solid pump during high pressure pipeline transporting thick pastes, largde axial impact force is exerted on the pipeline, which makes pipe clamps, supports and bolts of flange damage to failure. By using twin dynamic force transducers and designing coresponding installation components for the transducers, impact forces at different flow rates, positions of the pipeline and transportation pressures were measured. Conclusions can be drawn as following: impact force increases with increasing flow rate, and decreases with increasing distance from the outlet of pump. The increased amount of impact force with increasing flow rate is larger under larger transportation pressure than that under samller transportation pressure. It is better to transport thick pastes at low system pressure, and to install more pipe clamps in the front part, and reverse in the back part of pipeline.

Abstract: Engine fuel flow is one of the most important parameters of aero-engine performance, which can accurately reflect the actual condition of aero-engine. It'is possible to monitor the aero-engine fuel flow (FF) by reading the data of QAR (Quick Access Recorder). However, it's difficult to monitor the actual condition of aero-engine through the traditional method because of the vast amount of QAR data and the complexity of the engine itself. Feed forward process neural network is adopted to monitor the QAR-based aero-engine fuel flow . The results of the simulation are acceptable and show that the Neural Net model is an effective method to monitor aero-engine conditions.