Applied Mechanics and Materials Vols. 556-562

Abstract: In order to get better trade-off between detection performance and calculating complexity, an improved detection algorithm was presented here. QRD-M algorithm is performed for several layers firstly, and successive interference cancellation detection algorithm was used to detect the bottom several layers parallel, and the candidate sequence with smaller PAM was selected out as the answer. Simulation results show the validity of proposed algorithm.

Abstract: Making the video invigilation more easy is a hot topic in the research of intelligent monitoring system. This paper proposes the examinee identification algorithm based on the video surveillance. Firstly, transform the video frame to the orthograph by using perspective transformation, extract the desks template, and get the place of desk according to template matching, then get the place of examinee. Comparing the image about no people included and people included will detect whether examinee in his place by using the comprehensive method which is background subtraction and the normalized matching algorithm, so can statistical number of examinees. Experimental results show that this method is simple, has a good real-time performance and robustness.

Abstract: Machine vision system has been widely used for a variety of applications in industrial testing and measurements. However, image distortion caused by optical system and system re-positioning will bring errors to the machine vision detection system. This paper addresses on three types of image distortions including optical distortion and perspective deformation, image translation and rotation, and image scale change. To rectify optical distortion and perspective deformation, a black and white grid pattern is used as a standard template for finding the multiple matching points between distorted image points and ideal image points, and then a polynomial mathematical model simulating the geometric distortion is established. The distortion coefficients are calculated from the least square method. Image translation and rotation are compensated by using a floating fixture origin as the reference point. Image scale change is remedied by using a standard scale factor to shrink or enlarge an actual image to its standard size. The experimental results have demonstrated the effectiveness of the approach proposed.

Abstract: Because aluminum profile’s structure is complex and diverse, we need to match the different parameters for different profiles before automated detection of surface defects of aluminum profile. This process often requires manual input, affecting the detection efficiency. To solve this problem, we analyze the characteristics of aluminum profile, through GLCM algorithm and Gabor wavelet transform methods, which are image texture feature extraction methods to get aluminum profile’s texture feature, then we use the Support Vector Machine (SVM) classification algorithm based on radial basis function (RBF) core classify the feature, for the aim of matching parameters automatically. By feature extraction time and the recognition accuracy rate and other indicators to compare the experimental results of each method, derived using Gabor wavelet transform is the best both on recognition accuracy or identify time effects, and can satisfy the actual needs.

Abstract: Based on the deficiencies in evaluation of AHP, this paper adopts IAHP to evaluate 3 schemes for the aerospace testing process evaluation. Firstly, aerospace testing process evaluation model is established by using AHP in this paper. Secondly, we choose comprehensive integrity, reasonable effectiveness, safety and reliability, periodicity, expansibility, and environmental friendliness as the evaluation criterion. Thirdly, we choose 3 schemes including before and after the optimization. At last, 3 schemes are evaluated by IAHP and we get the evaluation result.

Abstract: As a strength parameter less dependent on loading conditions, crack initiation stress is suggested to be used as a lower limit for spalling strength. So far, no suggested methods are given by the ISRM to determine crack initiation stress. In order to understand the physical meaning of the various methods and determine this characteristic stress threshold accurately, we compared the similarities and differences between these methods and then analyzed their applicable scope. It is suggested that a comprehensive consideration be taken to select an appropriate method to identify the crack initiation of rocks in compression.

Abstract: In order to avoid the over discharge and less discharge situations, improve the coal recovery rate and promote the working environment of workers at the fully mechanized top-coal caving face, experiments for the research of the coal and rock character recognition were carried on underground. Vibration signal at the hydraulic support tail beam and the rear scraper conveyor under different conditions were acquired at the fully mechanized top-coal caving face using the self-developed mine portable data recorder. The time-domain indexes of the vibration signal were analyzed. Results show that the variance, skewness index and kurtosis index changes most obviously under various stage of top coal caving and can be used as the time-domain characteristic indicator for the coal and rock character recognition in the fully mechanized working face.

Abstract: Integrity is the capability of sending the alarm to users timely when the navigation system cannot be used, which is a significant parameter of reliability to the system. First, the paper analyses integrity concept and future evolutions in PPP application. And then, in this paper, the effectiveness of carrier phase Receiver Autonomous Integrity Monitoring (RAIM) for cycle slip detection is explored, and evaluates the aviliablity of detection.

Abstract: This article proposes a new algorithm applicable to H.264 based on motion vector coding length and high-pixel accuracy filter operator instead of linear interpolation. After half-pixel accuracy motion estimation, a high accuracy motion estimation can be calculated with the intermediate results. This algorithm can achieve high accuracy estimation and compensation while decreasing algorithm complexity. The computer simulation results show that when the new proposed algorithm for 1/8-pixel accuracy is used in QCIF, CIF, CCIR format pictures, total computing time reduces more than 20% and computing time used for fractional-pixel motion estimation reduces more than 50% while coding length only increases less than 10% and PSNR-Y is approximately equal.

Abstract: The mistake rate of in-orbit satellite diagnosis reasoning is a problem which is difficult to solve because of the complex technique frame of satellite and the bit errors of telemetry data. This paper proposed a diagnosis reasoning method based on credibility and degree of membership. And the credibility passing algorithm and the membership function prototype were given to support the diagnosis reasoning process. The argumentation indicates that the diagnosis reasoning mistake rate can be reduced with this method.