Advanced Materials Research Vols. 712-715

Abstract: In order to avoid some shortcomings such as poor accuracy and low signal-to-noise ration, an ultrasonic test system based on automatic and intelligent testing are introduced. After ultrasonic signal is transmitted and received; data processing, data saving and curve displaying are performed in this test system. To solve the problem of extracting the weak ultrasonic signals from the strong noise, an adaptive filter based on least-mean-square (LMS) algorithm is designed. The convergence factor of the algorithm is chose according adaptive fuzzy control rule. Experimental results show that the filter can inhibit the noise and extract the weak signals more effectively. It also can improve the robustness, convergence speed and detecting accuracy.

Abstract: The uncertainty in standard metal tank volume value verification is evaluated by using Monte Carlo Method. For second standard metal tank, verification is conducted with volume comparison method. A mathematical model of second standard metal tank volume measurement is established by using first standard metal tank to measure second standard metal tank. An analog simulation is conducted for verification value by using Monte Carlo simulation method, and hence the uncertainty in volume verification is obtained. Through comparison between evaluation result and traditional uncertainty propagation evaluation method, the result indicates that the difference cannot be ignored and the evaluation result by using Monte Carlo Simulation Method is more reliable.

Abstract: To resolve the problems of small module gear measurement with traditional methods, a new method for measuring the tooth profile deviations of small module gear using the optical image measuring instrument is put forward. According to the ISO 1328-1, the mathematical models of total profile deviation, profile form deviation and profile slope deviation are proposed. The involute profile measurement schemes are given. The results show that tooth profile coordinate values of small module gear can be measured automatically and effectively with the optical image measuring instrument, and the provided method has higher precision of getting measuring points and less fitting error of tooth profile.

Abstract: A set to the system is designed for detecting the drilling rig hydraulic system. In the system, the significant indicators of drilling parameters are collected, which include hydraulic oil temperature, pressure values of some important points and number of the bubble in the hydraulic oil. All data from sensors is real time displayed.So those faults are detected in time.

Abstract: In order to meet the developing requirements of the high-precision GNSS(Global Navigation Satellite System) receiver and spread-spectrum TT&C equipment, we researched high-precision simulating technology of DSSS (Direct Sequence Spread Spectrum) signal and proposed simulating technology of carrier phase and pseudo code phase based on correction technology online. This technology avoids sacrificing implement slice to improve phase precision and can simulate relative motion between receiver and object. In this paper, high-precision generating method of digital middle frequency signal is focused on. The effectiveness of this algorithm has been corroborated by theoretical analysis, simulation and applied to some spaceflight simulator successfully.

Abstract: This paper discusses the principle of design and performance of the air preheater thermocouple temperature monitor system, and the control system is realized with PLC and touch screen. Compared to the early device, the reliability is improved greatly, the device is free of maintenance, save so many resources, and the efficiency is improved greatly.

Abstract: In order to realize the real-time environmental monitoring for shipboard TT&C antenna-centrosome, this paper designs a monitoring system based on Modbus by analyzing current conditions, which contains sensor data acquisition terminal and video switcher. The designed system has many advantages, such as less project-related work, higher cost performance, convenient installation, easy debugging and etc. Actual application shows that temperature & humidity data and video information gathered meet the requirement need completely. Techniques in this paper can be referenced in other related fields.

Abstract: In the process of that based on the RSSI received signal strength indicator technique, resulting in the positioning accuracy is so low, since the simple RSSI, multipath, diffraction and non line of sight and other factors. In order to achieve higher accuracy node localization in wireless sensor, the paper is proposed based on the probability of recycling triangle centroid location algorithm in the RSSI technique,The probability of the cycle to handle triangle centroid localization algorithm. Through the Matlab simulation, compared with the traditional triangle centroid localization algorithm, the error is significantly reduced and positioning accuracy improved when the anchor point number exceeds a certain number.

Abstract: The 2D spectrum estimation based on uniform linear array is studied in this paper. MUSIC method is firstly introduced into array signal processing to realize the frequency and angle joint estimation. And the modified MUSIC method is then applied for two dim array signal processing to fulfill joint parameters estimation of coherent signal sources. Simulation results show the validity of the proposed method. Keywords: Super resolution;Array signal processing;Parameter estimation;MUSIC algorithm

Abstract: Meteorological data collection and monitoring is widely adopted in the traffic industry. Meteorological monitoring can ensure traffic safety and improve the traffic management level. According to the detection type the system is divided into several types: pavement visibility detector, road conditions detector, rainfall detector, wind speed and direction detector, etc. Subsequently the advantages and drawbacks or system working principle of various types are compared. Meanwhile the key issues and the future trend of development are presented.