Applied Mechanics and Materials Vols. 44-47

Abstract: Model help to understand the system there may be a signal reflection and impedance matching problem. Most fiber integrated circuits from Maxim use Current Mode Logic (CML), Positive Emitter Coupled Logic (PECL), and Low Voltage Differential Signal (LVDS) I/O formats. Language can be set up through the PSpice circuit model of the IC, with an ideal voltage controlled current source of alternative sources and active circuit elements. And the use of spice macro-model simulation to test the circuit performance of the chip interface design. In this paper, it takes the model of amplifier IC in GPON receiver front-end for example to shows the steps and importance of interface simulation in GPON system by PSpice macro-model.

Abstract: A nonlinear PID control method based on Smith predictor is presented in this paper to control the time delay systems. This method combines the Smith predictor with nonlinear controller. And the simulation study had been done for a first-order time-delay system. The results show that this method offer good static and dynamic characteristics, at the same time its disturbance-rejection and robustness are better.

Abstract: In this study, the Web-based Multi-Survey System was adopted, one or two choices available among five options, to set up questionnaire to get a nine-point scale with network programs. As an empirical research, which was conformed to the policy of Ministry of Education to promote technology abilities for teachers in Taichung County in 2009, the important and satisfied survey from Teachers’ Free Software Application workshops was analyzed by four approaches which were Importance-Performance Analysis, Simple Logistic regression model, Choquet integral regression model with respect to λ-measure, and Choquet integral regression model with respect to L-measure. By comparing MSE, Choquet integral regression model with L-measure obtained the best performance. Two crosshairs which were Hollenhorst’s overall mean and Choquet integral regression model with L-measure were positioned for I-P matrix. From results, the L-measure model had shown better sensitivity about quadrant distribution, and reflected participants’ real responses. At the same time, it was definitely known what to keep up the good work, concentrate here, or possible overkill through assessing Importance and Performance of teacher’s workshops.

Abstract: Oracle is a database management system supporting the object-oriented data model that is usually adopted by the storage technology of persistent object. This paper describes the main features and characteristics that an object-oriented database system must have to qualify as an object-oriented data model. The paper introduces how to describe and implement the main modeling elements of the object-oriented data model in Oracle database which are the main components of class diagram, including the class, attribute, method, inheritance and polymerization. The examples of SQL that the paper offers can successfully run in Oracle 10g.

Abstract: Wheel set is the major running components of a train. Online measurement of wheel set wear parameters is important for the safety of train. The acquisition and processing of wheel set profile image is the key problem in an online measuring method based on machine vision. Factors influencing the effect of image acquisition were analyzed. The main factors included environmental illumination, light reflection, CCD exposure time and light source change. An optimal threshold method based on entropy criterion and genetic algorithm for image threshold segmentation was proposed. The optimal threshold was found by iterative analysis. The image segmentation algorithm eliminated effectively the interferences in the image acquisition and extracted wheel set profile curve from varying background. Better segmentation effect ensured the measurement accuracy of wheel set wear parameters.

Abstract: Measurement of wheel set wear was an important step for the safety of train running. High-speed acquisition and processing method for high resolution image of wheel set based on the hardware platform of DSP (digital signal processor) and PC was proposed. High-speed acquisition and processing was completed by PC and DSP unit separately. PC and DSP unit worked in parallel operational mode. Ethernet transport program based on TCP was designed for data exchange. Asynchronous reset pulse generation circuits were designed. High resolution images of wheel set were captured in 500fps and asynchronous reset mode. Resolution of images was 1280*1024. The experimental results showed that this method improved image processing speed effectively.

Abstract: To implement indoor GPS signal tracking in standalone mode when the tracking loop is unlocked and data bit edge is unknown, the paper develops a modified Viterbi Algorithm (MVA) based on dynamic programming, and it was applied for GPS bit synchronization. Besides, two combination carrier tracking schemes based on Central Difference Kalman Filter (CDKF) and MVA module were designed for indoor GPS signal. The testing results indicate that the methods can successful detect bit edge position with high detection probability whether or not the tracking loop is locked. The co-operational tracking scheme is still able to perform when the signal quality deteriorate.

Abstract: The revolved concave surfaces are widely applied to both optical equipments and aerodynamic domain. The revolved surface is measured by digitized measurement with the coordinate measuring machine (CMM) in this paper. A CMM inspecting path planning which is different from traditional measuring method for revolved surface is given. An automatic algorithm of digitization on a CNC coordinate measuring machine for an unknown revolved surface is present. At the same time, this method is proved effectiveness through a practical measuring example of an optical part. The Measuring process and the measuring results are illustrated in detail.

Abstract: A new method approach is presented to solve isomorphism identification of kinematic chain topology graphs. Kinematic chain topology graphs are depicted with loop-code based on the characteristic of kinematic chain topology graphs. The number of binary links in the limbs of topology graphs is arranged in group according to links with multi points of connection．Although the order of limbs in the groups and the order of links with multi points of connection outside the groups can change, the planar message of topology graphs can not change. Thereby forming loop-code.This representation is straightforward and not affected when drawing modes and labeling ways change in topology graphs．

Abstract: Both the PSO (particle swarm optimization) for global search algorithm and the CMAC (cerebella model articulation controller) algorithm are used in the speed loop of direct torque control system in the permanent magnet synchronous motor. Firstly, the PSO algorithm is applied to search the optimal PID parameters in the domain space, and then the CMAC neural network is adopted to learn and train of the results which derive from the output of the PSO algorithm to furthermore optimize the PID parameters which can improve stability of the system. The DTC control system based on PSO with CMAC algorithmic and the traditional DTC (direct torque control) control system are established and simulated in the MATLAB circumstance whose results were all compared. It revels that the DTC control system based on PSO with CMAC algorithmic is fast response, ideal flux, and good anti-jamming.