Applied Mechanics and Materials Vols. 220-223

Abstract: With large scale application of the power electronic devices and frequency conversion devices, the harmonic pollution in the grid becomes more and more serious. It has brought serious harm to the electrical equipment and the safe and stable operation of the power system. In view of this, this paper built a harmonic detection system based on Ethernet. MCU C8051F040 is used as the field detection instrument, and ARM9 processor is used to build the Ethernet gateway. Field data can be sent to the gateway from MCU by RS485 bus. By writing the related web server code and CGI code, the remote monitoring data can be achieved through the IE browser.

Abstract: This paper describes a speech pre-processing and feature extraction methods and described the principle of generalized regression neural network (GRNN). In order to use neural networks for speech recognition, this article uses the variable frame-shift average frame method to average the characteristic parameters of the collected voice frame, and the feasibility of the variable frame-shift average frame method in neural network input parameters normalization is verified by experiments. In this paper, according to this method, the speech recognition based on the generalized regression neural network (GRNN) successfully ported to an embedded system, and realized the pipe climbing robot’s real-time speech control.

Abstract: The analysis of the ECM model expressed by an equivalent circuit is helpful to understand the ECM characteristics, such as the removal rate and machining accuracy. However, the parameters in the ECM equivalent circuit have not been determined yet, although several kinds of equivalent circuits were proposed. In this research, the parameters of the ECM equivalent circuit were determined experimentally, and the determination reliability was discussed.

Abstract: This paper researches on embedded system design based on MC9s12Dp256 microcontroller for vehicle semi-active suspension. The hardware design of suspension control unit (SCU) is introduced. The integrated control strategy which integrates Skyhook and MiniMax strategies is proposed. The hardware-in-the-loop simulation (HILS) test on a two-degree-of-freedom quarter car semi-active suspension system model is carried out. The functions of SUC are verified and the performance of passive suspension and semi-active suspension is compared. The simulation results indicate that the performance of SCU achieves design requirement. In comparison with passive system, the control effect of integrated control strategy can be improved in ride comfort and drive safety.

Abstract: In this paper, the gap-width in pulse ECM was detected by measuring the peak current responsive to the applied pulse voltage, and the influences of machining conditions on the detection sensitivity were investigated. It was found from experimental results that the sensitivity is increased by using the lower concentration electrolyte and electrolyte height. In addition, the machining experiment also showed that the sensitivity can be kept constant by removing by-products timely from the gap area.

Abstract: Due to the limited bandwidth resources, traditional networks can not completely guarantee the Quality of Service (QoS) among users with new class, thus how to allocate network resource effectively becomes a very important problem. In this paper, we propose an algorithm for an integrated cellular/WLAN network, namely Satisfaction-based Dynamic Bandwidth Allocation (SDBA) algorithm. The main objective is to guarantee users’ satisfaction through allocating network resource dynamically according to proportional fairness based degradation and one-by-one search based degradation. Numerical results show that our proposed algorithm not only reduces new call blocking probability (NCBP) and handoff call dropping probability (HCDP), but also maintain fairness among users.

Abstract: The hardware modules of electronic password lock were designed in the paper. The single chip microcomputer AT89S51 was chose as the main control chip to control the operation of the whole system. The 4×4 matrix keyboard was devised and the unlocking circuit was made up of the driving circuit and unlocking part. The alarm circuit was composed of a piezoelectric buzzer and its peripheral circuit. The serial electrically erasable memory chip AT24C02 of ATMEL firm was chose as the memory cell for losing electricity. The power supply circuit including of the commercial power supply circuit, power failure detecting and electronic switching circuit and the battery charging circuit was designed. The module functions of the whole system were combined and the hardware circuits of the electronic password lock were designed successfully.

Abstract: This paper represents the theories of mathematical model of DS-CDMA system, principle of Kalman filter and layered space-time coding. Then, for the purpose of overcoming the disadvantages of traditional multi-user detection algorithm, the paper proposes the layered space-time multi-user detection algorithm based on kalman filter. Simulation results show the effectiveness of the proposed algorithm, such as the convergence speed is quickened, bit error rate is reduced greatly and channel tracking capability is improved significantly.

Abstract: The two lowest single-particle hole states in two vertically coupled quntum dots (CQDs) are investigated by using the six-band k • p model. A bonding–antibonding ground-state transition is observed with an increasing interdot distance. This result is counterintuitive since the antibonding molecular ground state is never observed in natural diatomic molecules. By comparing the wavafunction component of hole, the results verify that the reordering of bonding and antibonding orbitals with an increasing interdot distance is caused by spin–orbit interaction of holes.

Abstract: The ZigBee wireless sensor network has been already widely used in many areas of industrial control, home network and medical equipment. A wireless mesh data transmission network based on the chip CC2530 of TI and the ZigBee Protocol stack was established with the practical application, in which any two nodes can communicate directly. The experimental results show that the designed network has special features of the high speed of data transmission, low delay, fault tolerance and flexibility. Finally, application in the wireless intelligent light pen CMM measurement system was analyzed.