Applied Mechanics and Materials Vols. 475-476

Abstract: In this paper, we present a new mathematical model of three-axis force sensor for underwater robot fingers. We designed a kind of sensor based on this model which has a simple structure and can be miniaturized easily. By this model, they can be calculated that the magnitude, direction of finger force. Moreover, we present a new compensating method to decrease the error caused with the variation of temperature and pressure of water and caused with bending of the beams by symmetrical electronic circuits. We proposed compensation block method to solve the problem of heavy lead wire which affecting finger moving in underwater. Finally, an experiment is performed to verify the proposed model.

Abstract: The aim of this paper is to investigate how to use the contextual knowledge in order to improve the fusion process. The concept of multisensor information fusion model based on the Dempster-Shafer Theory is introduced. The resulting information of the architecture is combined using similar sensor subset and dissimilar sensor subset. We demonstrate the effectiveness of this approach using the uncertain and disparate information compared to primary mass assignment techniques.

Abstract: To improving the efficiency of data aggregation in wireless sensor networks (WSNs), , authors proposed an efficient data aggregation scheme for WSNs with tolerable measurement bias. Due to sensors located in the same relative small area have similar readings, it is unnecessary for all nodes in this area transmit their values to the aggregator. Comparison with all nodes send their data to the base station, part of sensors keep silent to the servers request will has little impact on the final aggregation result and reducing the energy consumption effectively. Experiment shows the proposed scheme lowers the energy consumption effectively with tolerable bias.

Abstract: Aiming at some uncertainty problems such as quality inspection of adhesive structure and risk assessment in the practical engineering application, a possibility estimation model is established. Firstly, according to the fuzziness, randomness and uncertainty of the measurement data, a transformation method of possibility distribution with non-single peak values and nonlinearity is proposed from probability density function. Secondly, for possibility distributions of measurement data of each sensor, a kind of possibility fusion rules is put forward, then the fusion distribution is estimated by the possibility mean. Finally the model is applied to the mechanical property estimation of adhesive structure, and the result forecasts the quality. The proposed model with strong applicability, not only provides convenience for the operations among possibility distributions, but also offers new ideas and new methods to deal with uncertain problems.

Abstract: Aiming at solving the incompatibility and interoperability among multiplexed sensor elements in complicated system, the paper designed a XML-based TEDS for networked sensors, The paper introduced XML technology, analyzed the TEDS defined in IEEE1451.2. In virtue of XML, integrated IEEE 1451.2 with XML technology, the designed TEDS parsed a wide variety of transducer’s information; the XML-based TEDS applied in heterogeneous system proved to a viable means of achieving interoperability.

Abstract: A node positioning model of UWB wireless sensor networks is proposed, and positioning error of the model is investigated through simulation. High accuracy of positioning is achieved if all four reference nodes have LOS(Line of Sight) information path, however, even if one reference node does not have a LOS information path, the positioning error will no less than 5 m when the SNR(Signal to Noise Rate) lower than 30 dB, so the SNR or reference node should be increased to assure the positioning accuracy.

Abstract: For multisensor network systems with unknown cross-covariances, a novel multi-level parallel covariance intersection (PCI) fusion Kalman filter is presented in this paper, which is realized by the multi-level parallel two-sensor covariance intersection (CI) fusers, so it only requires to solve the optimization problems of several one-dimensional nonlinear cost functions in parallel with loss computation burden. It can significantly reduce the computation time and increase data processing rate when the number of sensors is very large. It is proved that the PCI fuser is consistent, and its accuracy is higher than that of each local filter and is lower than that of the optimal Kalman fuser weighted by matrices. The geometric interpretation of accuracy relations based on the covariance ellipses is given. A simulation example for tracking systems verifies the accuracy relations.

Abstract: Chinese herbal medicine with no side effects can help people resist disease and keep healthy, due to predatory excavation, and heavy deforestation, the destruction ecological environment, lots of the precious Chinese herbal medicines are on the edge of exhaustion. In order to protect Chinese herbal medicines and do artificial cultivation, the paper presents a real-time monitoring system based wireless sensor network. The system gives the hardware design of wireless sensor node and software implementations. The nodes are mainly responsible for collecting and transporting the environment parameters of the Chinese herbal medicine including temperature, humidity and light intensity and so on, and send the data through the GPRS module to the remote monitoring center. The system can make the artificial cultivation of the medicines more modern, scientific and objective.

Abstract: Nanocrystalline ZnO thin films were grown by pulsed laser deposition technique on polycor substrates. The operation laser fluence of 2.0 J·cm^-2 and film thickness of 60 nm were fixed while varying target-to-substrate distance (20-135 mm), substrate temperature (100-500 °C) and annealing temperature (300-700 °C). Structural and morphological investigations carried out by reflection high-energy electron diffraction, scanning electron and atomic force microcopies, have shown a strong influence of deposition technique parameters on grain size of the zinc oxide films. Atomic force microscopy showed the surface roughness decreasing and grain size increasing with the annealing treatment of the as-deposited films. The resistivity and Hall mobility of ZnO films were increased with substrate temperature and/or annealing temperature rise. The gas sensing characteristics of the films were investigated towards nitrogen dioxide and ammonia at a selected operating temperature (22 and 50 °C).

Abstract: Insulator fault may lead to the accident of power network,thus the on-line monitoring of insulator is very significant. Low rates wireless network is used for data transmission of leakage current. Making data compression and reconstruction of leakage current with the compressed sensing theory can achieve pretty good results. Determination of measurement matrix is the significant step for realizing the compressed sensing theory. This paper compares multiple measurement matrix of their effect via experiments, putting forward to make data compression and reconstruction of leakage current using Toeplitz matrix, circulant matrix and sparse matrix as measurement matrix, of which the reconstitution effect is almost the same as classical measurement matrix and depletes computational complexity and workload.