Applied Mechanics and Materials Vols. 541-542

Abstract: In this paper, we propose an efficient parts surface defect detection method using SVM algorithm, and particle swarm optimization is used to make parameters selection for SVM. The proposed parts surface defect detection systems is made up of six parts, and the main ideas of our method lie in that we exploit computer vision and machine learning in the research field of mechanical manufacturing and automation. We convert the parts surface defect detection problem to the classification problem, and the images of parts surface are used as testing samples. The SVM algorithm regards the classification problem as the constrained optimization problem. The classification accuracy is determined by the quality of parameters selection. Hence, particle swarm optimization is exploited to make parameters selection for SVM by defining two fitness functions. Afterwards, the best particle of the current population and the gbest is obtained. Utilizing the output from the particle swarm optimization then the parameters for SVM can be obtained. Finally, experiments are conducted based on a dataset with 563 samples, and experimental results illustrate that the proposed is quite effective for parts surface defect detection.

Abstract: In this paper, We propose a effective method which joint transmit antenna selection (TAS) and artificial noise to promote communication security in MIMO wiretap channels. Firstly, based on TAS protocol, the transmitter selects one antenna (the max-antenna) that maximizes the instantaneous signal-noise-ratio (SNR) at the receiver. Secondly, the transmitter uses the max-antenna to transmit valid data, and simultaneously, uses the remaining antennas to transmit artificial noise which only affects the eavesdropper. Thirdly, The receiver and the eavesdropper employ maximal-ratio combining (MRC) to combine the received signals. We focus on the practical scenario where the transmitter does not have any channel state information (CSI) of the eavesdroppers channel. Our joint TAS and artificial noise scheme (TAS-AN) have low complexity, and can enhance the systems security. The numerical simulation results verify our analysis.

Abstract: For company to extend their RFID applications ceaselessly, the fundamental challenge is how to satisfy enterprise applications more effectively, while avoids mainframe server purchased and existed servers leave unused. It needs to decentralize work by using several RFID middlewares. So load balancing method is required for preventing centralization work in certain RFID middleware. In this paper, as a solution of tackle the challenge, we proposed a new load balancing approach based on mobile agent for RFID middlewares, which includes: information gathering policy, transfer policy, selection policy and location policy, and three agents are developed: load-info monitoring agent (LIMA) compliant to monitoring local host workload status; load-info gathering agent (LIGA) compliant to gather local and global load information; load transfer mobile agent (LTMA) compliant to choose the independent set and the appropriate scheduling scheme and implement the relocation work.

Abstract: The Internet of Things (or IoT for short) [1] refers to uniquely identifiable objects and their virtual representations in an Internet-like structure. Nowadays, the IoT has become to the National Strategic. The basic technology of IoT is growing fast. A comprehensive real-time location system that used to tracking object in time is becoming more and more important. In this paper, a new RFID localization with passive UHF RFID-tags is presented. It is shown how persons of devices that are equipped with a RFID tag and can be tracked. The method is based on fingerprint and phase. We will find the position of the target object by two steps. First, we will calculate the first-order sub-region using SVM algorithm. Then using Dempster-Shafer theory with phase in different frequency will give us a more accurate position.

Abstract: In order to diagnosing new fault for hybrid system which is lack of experiential knowledge and historic knowledge, semi-quantitative fault diagnosis method based on graph theory and fuzzy theory combined with functional fault analysis (FFA) theories and Failure Mode and Effects Analysis (FMEA) is studied. And a multi-hierarchical functional directed graph modeling method is proposed for aircraft system fault diagnosis. Nacelle Anti-Ice subsystem of an aero engine is taken as a specific application to present the detailed MHFDG modeling method. The proposed modeling method is suitable for fault diagnosis of newly developed hybrid system.

Abstract: This paper describes a method for vehicles flying Trajectory Planning Problem in 3D environments. These requirements lead to non-convex constraints and difficult optimizations. It is shown that this problem can be rewritten as a linear program with mixed integer linear constraints that account for the collision avoidance used in model predictive control, running in real-time to incorporate feedback and compensate for uncertainty. An example is worked out in a real-time scheme, solved on-line to compensate for the effect of uncertainty as the maneuver progresses. In particular, we compare receding horizon control with arrival time approaches.

Abstract: The virtual flight simulation of the Basic Finner projectile has been investigated through coupling solving unsteady Navier-Stokes equations, rigid-body six degree-of-freedom motion equations, guidance, navigation and control law. The flow solver uses a finite-volume method based on structure grid with dual time stepping, the chimera method is used to simulate relative motions, the fourth-order Runger-Kutta method is used to solve the motion equations. A closed loop feedback control law with PID control is required for the elevator to attain the commanded deflection. The predictions show that the PID parameters for the controller must be correctly selected to obtain the proper response. Simulation results show that the virtual flight simulation platform that we developed is capable of solving the complicated unsteady flows with moving boundary, has a strong applicability to engineering application.

Abstract: Many research papers implemented fault diagnosis and prognosis when there are many history data. However, for some capital and high reliability equipment, it is very difficult to acquire some run-to-failure data. In this case, the fault diagnosis and prognosis become very hard. In order to address this issue, continuous hidden Markov model (CHMM) is used to track the degradation process in this paper. With the degradation, the log-likelihood which is the output of CHMM will decrease gradually. Therefore, this indicator can be used to evaluate the health condition of monitored equipment. Finally, bearing run-to-failure data sets are used to validate the model’s effectiveness

Abstract: A built-in position sensing circuit for a singly-fed electrostatic actuator, where only the stationary element has voltage feeding wires, is discussed. The sensing is realized by superposing a high-frequency sensing signal onto the actuating wires. The paper mathematically analyzes its operation and discusses potential problems from the experimental results. The problems are vulnerability of the sensor operation to the change of impedance of the actuating power sources and to the gap variation. Electrode segmentation is proposed as a possible solution.

Abstract: In order to get a quantitative and simple supporting scheme of deep foundation pit, this paper creatively develop a simplified method of supporting system selection based on the fuzzy optimization theory. The simplified method determines a preferred equation of the supporting system at first. Then the best solution is selected based on the preferred equation. Based on the simplified method, the analysis of the foundation excavation for Chuangye Dasha in Taiyuan has been performed. The result of the analysis shows that the method is reasonable and scientific.