Applied Mechanics and Materials Vols. 241-244

Abstract: Hall current sensor is a new generation industrial sensors which was widely used in electrical measurement. After introducing the current measurement by hall sensor, the 3D model of current-carrying conductor was built by ANSYS, and the effect caused by current-carrying conductor’s shape and the position of hall sensor was analyzed. Along with the effect of electromagnetic field of adjacent phase current-carrying conductor, the ferromagnetic shield was proposed to reduce this effect and improve the measurement accuracy. The theoretical analysis is verified by the simulation results, which can do a lot in improving the product.

Abstract: In this paper, a novel GPS (Global Positioning System) and DR (Dead Reckoning) system which is based on the accelerometer and gyroscope integrated system is designed and implemented, a new accelerometer calibration algorithm is also proposed. In this system, the odometer used in traditional DR system is replaced by a MEMS tri-axis accelerometer in order to decrease the cost and the volume of the system. The system is integrated by the Kalman filter and a new mathematical model is introduced. In the purpose of reducing the effect of the accumulated error caused by drift and bias of accelerometer, the accelerometer is calibrated online when GPS performs well. In this way, the integrated system does not only could obtain the high-precision positioning in real time, but also performs stably in practice.

Abstract: A cataluminescence (CTL)-based gas sensor utilizing nano-sized Mn_1.5Zr₂O₇ as the sensing material for the determination of hydrogen sulfide in air was proposed. The gas sensor showed high selectivity for hydrogen sulfide at 450 nm and satisfying activity at 320°C. The linear range of the CTL intensity versus concentration of hydrogen sulfide was 2~95 mg/m³, and the detection limit (3σ) was 1.5 mg/m³. No interference was observed while the foreign substances, such as formaldehyde, ammonia, ethanol, benzene, carbon monoxide and sulfur dioxide, were passing through the sensor. The gas sensor displayed good stability for continuously introducing hydrogen sulfide over 60 h, and allowed real-time monitoring of hydrogen sulfide in air.

Abstract: Six-axis heavy force sensor will be used to measure the dynamic load of the heavy load equipment. Therefore, the dynamic character of the six-axis heavy force sensor is important. In this paper, a six-axis heavy force sensor based on the Stewart platform is developed. A dynamic measurement system is established to measure the dynamic character of the six-axis heavy force sensor. The hammer impact method is used to measure the natural frequency of the six-axis heavy force sensor. The power spectrum analysis of each channel is conducted. And the natural frequency of each channel is obtained.

Abstract: Some alterations of similar spectral reflectances cannot be distinguished accurately for their lower spectral resolution when the traditional methods, such as, band ratio and principal component analysis are used to extract alteration information from Landsat ETM multi-spectral data. In this paper, the band1~band7 of MODIS whose wave lengths are among 10~500nm, together with ETM’s multi-spectral bands, whose spatial resolutions are 30m, are chosen in the execution of data assimilation. After the third order wavelet transformation, the low-frequency component of ETM data are replaced by the MODIS data subsequently, then the inverse wavelet transform is in progress. The result of data assimilation consists of not only ETM’s spatial information but also MODIS’ spectral information. At last, four bands of assimilation results are selected to process PCA transform, as a result, two types of alteration in the study area are extracted accurately according to their components.

Abstract: According to the temperature, humidity, air quality and other environmental factors, the indoor environment monitoring system is designed, which collects the signals of a sensor using the NI company’s WSN module, uploads to the computer, and uses graphical programming software-LabVIEW, for PC software design. The function of real-time display and alarm of data, the alarm history records, and data storage in the different positions in the room environment are realized, and then the indoor environment monitoring system is built quickly.

Abstract: Wireless Body Area Network (WBAN) can implement the wireless communication between several micro-sensor units, so as to meet demand of medical remote monitoring, disease control, disease prevention and others. In this paper, we will analysis in-depth of some characteristics of three routing protocols commonly used in wireless sensor network, including energy consumption, transmission rate, network stability and unexpected resilience of communication. There are also some statements for both the strengths and weaknesses of each protocol and the improvement advices, finally according to the characteristics of each protocol to analyze the respective applicable WBAN types. By improving the routing protocols, WBAN can provide more practical and beneficial applications in the medical, entertainment and other fields, thereby the popularity of it will be improved.

Abstract: This paper issues the D-S evidence theory and modifies the fusion rule according to the relation of time and the NH3 content in water. A few concepts of D-S evidence theory and D-S evidence combination rule are presented. The modified D-S algorithm is simulated in time and space fusion of multi-sensor measurement system information. It could distinguish the main factor that changing the NH3 content in water. The measurement system cost could be decreased.

Abstract: According to the demand of coal mine safety monitoring, this paper proposes an improved clustered wireless sensor networking scheme. It analyzes the node sleep and wake-up mechanism, topology control, routing protocol, and designs the corresponding routing protocol LEACH-i. Finally, it carries out the system simulation.

Abstract: The internal link loss characteristic inference has become an increasingly important issue for operating and evaluating a wireless sensor network. In this paper we propose a new algorithm, based on MPLE algorithm and binary hamming distance and hop count, to infer the internal link loss characteristics. First, we use the MPLE model to part the problem of inference into the serial of sub-problem, a sub-problem is compose of subtree that contain two leaf nodes. Then, we select the subtree by using hamming distance of the sequences at each pair of nodes and incorporating the hop count available at each node in WSN. finally the Pseudo-Likelihood Function (PLF) is used to solve the problem. The simulation shows that the link loss performance parameters can be inferred accurately, and the proposed algorithm scales well according to the sensor network size.