Applied Mechanics and Materials Vols. 336-338

Abstract: In this paper, we present the design and testing of a simple yet accurate transducer for measuring strain in reinforced concrete bridges. Lessons learned from two earlier versions of the transducer, the first of which was incorporated into the design constraints and criteria. The following sections present the transducer design process, review the calibration and lab testing of the transducer prototype, and summarize the transducer performance in the field.

Abstract: To do Validation and Verification" of wireless vibration sensor nodes in NPPs (nuclear power plants), embedded system software test should be done. The test index is analyzed firstly; then the method of 'Temb' was introduced to analysis ADXL202 vibration nodes; the characteristic of system was used to establish LITO(life cycle, Infrastructure, Techniques, Organization) matrix, they are of emphasizing safety, application in harsh environment, using algorithms of technology and science and so on. The acceleration circulation method using fixed time cycle pretest by instrument and other weak was proved to be infeasible though FMEA (failure modes and effects analysis). Then FTA (fault tree analysis) is used to analyze system, so the software filter and real-time cycle test method were used to improve test precise and reliability of node vibration measurement. Experiments have proved its effective.

Abstract: A pair of concentrically placed gold electrodes is utilized in contact with human skin surface for moisture evaluation. The electrical impedance spectroscopy is measured within a frequency range of 100Hz to 5MHz. It is showed that, in case of relatively dried stratum corneum, reproducibility of measured impedances will decrease significantly in lower frequency range. The integrality of impedance frequency locus is correspondingly dependent on skin moist state. On the other hand, in case of relatively wetted stratum corneum, an integral locus can be obtained and Cole-Cole arc model can be applied for quantitative calculation. The integrality of the locus is introduced as a supplemental parameter. Experimental results with moistened filter paper as well as human skin indicate that, the skin moisture can be better represented both graphically and quantitatively.

Abstract: Smart home system is the inevitable trend of home network in the future. In this article, it built one interior network of smart home system based on ZigBee technology, designed one Home gateway, and configured one embedded Web server Boa on the gateway to realize one interactive network inside and outside the smart home, to provide one solution forwidely adaptation and energy saving smart home system.

Abstract: Inertial Navigation System (INS) and Global Positioning System (GPS) are commonly integrated to overcomes each systems inadequacies and provide an accurate navigation solution. The integration of INS and GPS is usually achieved using a Kalman filter. The accuracy of INS/GPS deteriorates in condition that a priori information used in Kalman filter does not accord with the actual environmental conditions. To address this problem, an improved Sage-Husa filter is presented. In this method, the measurement noise characteristic is adjusted if and only if filtering abnormality exists, avoiding filter instability and reducing computational burden caused by adjusting noise characteristic too frequently in Sage-Husa filter. Simulations in INS/GPS integrated navigation showed improvement in positioning accuracy.

Abstract: Rao-Blackwellized Particle Filter (RBPF) is suitable for solving the linear/nonlinear mixed Terrain-Aided Navigation (TAN) problem. But the Particle Filter (PF) part of RBPF is Standard Particle Filter (SPF), causing particle diversity reduction and even filters divergence under extreme conditions. To get a better estimation of the errors of INS, this paper proposes an improved approach called Regularized Rao-Blackwellized Particle Filter (RRBPF). After updating the nonlinear state and corresponding importance weights, RRBPF resamples from the Epanechnikov kernel and then get the resampled particles through a linear transition process. Theoretically, the resampling part of RRBPF is equivalent to resampling from the approximated continuous posterior probability density function. Shuttle Radar Topography Mission (SRTM) terrain data is used in simulations to investigate the performance of RRBPF. Results show that RRBPF can provide more accurate estimation of TAN and bear larger initial position error than Sandia Inertial Terrain Aided Navigation (SITAN).

Abstract: To obtain real-time navigation data, actual flight involves a lot of efforts as well as a heavy financial budget, and the collected data can hardly be reused. Visual simulation system for strapdown inertial navigation was developed. The system is based on object-oriented thought and modular design, outputs SINS simulation data in different flight conditions and precisions, and shows simulation data on virtual multi function display. The system has the feature of flexibility and extensibility and can be used to reduce effectively the experimental expense and shorten the developing period of strapdown inertial navigation system. The real-time SINS simulation data output is of enormous engineering significance to verify the inertial navigation system algorithm, and complete the integrated avionics systems cross-linking experiments in laboratory.

Abstract: This paper presents a robust state estimation and 3D environment modeling approach that enables Micro Aerial Vehicle (MAV) operating in challenging GPS-denied indoor environments. A fast, accurate and robust approach to visual odometry is developed based on Microsoft Kinect. Discriminative features are extracted from RGB images and matched across consecutive frames. A robust least-square estimator is applied to get relative motion estimation. All computation is performed in real-time, which provides high frequency of 6 degree-of-freedom state estimation. A detailed 3D map of an indoor environment is also constructed.

Abstract: Motivated by applications to sensor, peer to peer, and ad hoc networks, we study the problem of gossip-based averaging estimation. Unlike the previous researches, we propose a novel agent time model with non-uniform ticking probability. Based the novel model, we use a pair-wise-typed gossip algorithm to estimate the unknown statistical parameter from a set of noisy samples. The convergence of this algorithm is analyzed in probability sense. The agents states will converge to the spatial average of estimated parameters, and the convergence rate can be improved by adjusting the ticking probabilities of agents. Furthermore, we propose an optimization method for ticking probabilities by the projection subgradient. An illustrative numerical example is provided to demonstrate the usefulness and flexibility of the proposed approach.

Abstract: The sensor control is concerned in this paper to exploit the multi-object filtering capability of the sensor system. The proposed control algorithm is formulated in the framework of partially observed Markov decision processes as previous work, while it adopts a new reward function (RF). Multi-object miss-distance can jointly capture detection and estimation error in a mathematically consistent manner and is generally employed as the final performance measure for the multi-object filtering; therefore, the predicted multi-object miss-distance can be naturally selected as a RF. However, there is no analytical expression of the predicted multi-object miss-distance generally. The computation of this predicted miss-distance is discussed in detail. Future work will concentrate on providing a complete comparison of different sensor control schemes.