Applied Mechanics and Materials Vols. 246-247

Abstract: How to transmit quickly and accurately the messages to all nodes, this is the basic problem which urgently needs be resolved in the network. In this paper, the problem on fault-tolerant broadcasting for the directed communication network is studied. First the directed communication network is mapped to the digraph based on graph theory. Then a scheme on fault-tolerant broadcasting is obtained for directed communication network, and its time bounds are given.

Abstract: In order to reveals the dynamic, nonlinear work process of three-phase SPWM inverter, simulation model of three-phase full bridge voltage source SPWM inverter was built. Typical figure of voltage, current and spectrum was given and analyzed. Figures include line voltage of load, phase voltage of load, neutral point voltage of load, source current wave, Fourier analysis, Total Harmonic Distortion of voltage and current, inverter input impedance, line to line impedance. This Simulation model and results can be used as auxiliary in teaching, scientific research and product development. This simulation model was intuitive, commutative, being able to display graphs dynamically. Using this simulation model in class, the difficult in teaching three-phase full bridge SPWM inverter will be solved, it can also advance students’ studying interests and strengthen their understanding and save class hours. This simulation model has important value.

Abstract: The characteristics of assembly of vehicle transmission have been analyzed in this paper. General structure of PC-cluster virtual assembly environment of vehicle transmission based on dual-channel projection was described in detail. According to the characteristics of virtual assembly, analysis on technology of spectra stereoscopic display was performed. A geometric correction method of mechanic correction combined with software correction was proposed on the basis of arrangement form of curtain wall and the type of projector. Dual-channel synchronization mechanism in combination with the principle of PC-cluster was put forward. The application of a practical example in the virtual environment was realized for verifying the aforesaid methods and technologies.

Abstract: In order to achieve wide range for target search and monitor in all-weather, a zoom optical system with long focus length is designed which is used for visual light and middle infrared observation in this paper. In this system, the visible and infrared optical paths share a fixed R-C mirror in the foreside, on whose image surface the parallel plates is used to separate the light beam. Then the dual wavelength band zoom is achieved by two optical transmitted systems whose aperture is 100mm, Zoom range is 300mm~900mm for visual light and 250mm~750mm for middle infrared.This system has stable image and good imaging quality, satisfies the requirements of the application.

Abstract: NoSQL database is the broad definition of non-relational database. MongoDB is one of the most popular NoSQL database nowadays, and it is a schema-free and document oriented database, which has great query performance with huge amount of data and great scalability. More and more companies have adopted MongoDB, as increasingly large scale data is being stored in MongoDB, design philosophy and query optimization issues become growing concerns. This paper attempts to give the data storage structures of MongoDB on vehicle management information system. Based on this system, this paper gives two design philosophy and five different query optimization methods for MongoDB and gives the key code and diagrams of MongoDB optimization methods.

Abstract: To reveal the variation of the inner flow field on a single function shower, numerical simulation was conducted for single-phase flow using water as the working medium. The standard k-ε turbulence model is employed to simulate inner flow characteristics. To improve the uniformity of outlet flow, according to the simulation results of the old shower, the mold structural have been modified. The results show that, the outlet shape and different size will affect the internal flow field. According to the old shower analysis of the flow, speed of the outlet fluctuations are more obvious, while the improved shower flow rate of the outlet distribution is more uniform and old shower exists of vortex in the two shares of water region, but improved shower vortex is smaller and the distribution of flow is also better than the former.

Abstract: This paper build general regression neural network building conservation technology project appraisal model, Written software programs with MATLAB7.0 neural network toolbox to appraise building conservation technology project, trained and tested network by 17 ventilation samples, shows that GRNN have a good feasibility for appraisal. The main advantage of the GRNN model reflects four aspects. First of all, GRNN is a very simple and fast learning procedure thus it has less training time. Second, it is unnecessary to define the number of hidden layers or the number of neurons per layer in advance. Third, GRNN can handle linear and nonlinear data. Fourth, adding new samples to the training set does not require re-calibrating the model. Finally, it has only one adjustable parameter thereby making overtraining less likely. Because of these advantages, GRNN can be applied to many fields with other forecasting approaches or appraisal. GRNN building conservation technology project model building and training, testing can use neural network toolbox of MATLAB software.

Abstract: Vulcanization is one of the important processes to manufacture water-lubricated metal rubber bearing. Since the vulcanizing quality of the bearing is mostly influenced by process prameters, how to determine the optimal process prameters becomes the key to improving the part quality. In this paper, a combining RBF artificial neural network with improved genetic algorithm method is developed to optimize the vulcanizing process. The result shows that the combining ANN/GA method is an effective tool for the process optimization, comparing with the Taguchi DOE technique, overall performance of the bearing has significantly improved under the optimal process parameters.

Abstract: A new approach was proposed to estimate the reliability of a machine component when the probability density functions of stress and strength can not be exactly determined or only finite experiment data of stress and strength are available. The conventional universal generating function was introduced and then it was extended to represent the discrete interval-valued random variable. The experimental data of stress and strength were formulated as two discrete interval-valued random variables. Based on the extended universal generating function, a discrete interval-valued stress-strength interference model was proposed. An approach was proposed to solve the proposed stress-strength interference model and it can be used to calculate the upper and lower bounds of the component reliability. An example was given to demonstrate the proposed approach. It is showed that the proposed approach is suitable to the reliability estimation of a machine component when only finite experimental data of stress and strength can be obtained.

Abstract: Generally, the shape index n is selected in a form when design the inlet-exhaust system using traditional super-ellipse method. Unfortunately, this selection process is time-consuming and not precise enough, so the cross-section designed by super-ellipse method may get distortions easily, which influences the inner flow and the total pressure of the inlet-exhaust system greatly. Associating the shape index n with the variation pattern of the inlet-exhaust cross-section, an improved super-ellipse method is developed to design the inlet-exhaust system. This method ensures the precision and uniqueness of shape index n for any cross-section in an adaptive way. The numerical simulation results show that the S-shape inlet designed using this method has high total pressure recovery coefficient and lower distortion coefficient, the S-shaped nozzle has high total pressure recovery coefficient and thrust coefficient.