Applied Mechanics and Materials Vols. 239-240

Abstract: The human body model scanned by a structured light scanner is based on the scan coordinate system. Since the structured light scanner is not fixed, when the scanner scanning human body in different position, we can get several models, the coordinates of the same point on these models are not the same. In order to solve this problem, we propose a method. We extract facial feature points with the use of mean curvature analysis. The feature points are used to determine the digital human head model coordinate system. We can convert the human head models from the scan coordinate system to the digital human head model coordinate system. After the conversion, the coordinates of a same point on different models are approximately the same, which can make the use of scanner more efficiency and user-friendliness.

Abstract: In order to evaluate geometrical characteristics of proppant scientifically and accurately, both of the theoretical analysis and the experimental method were adopted. By binaryzation processing of the particles digital image, using chain code technology to realize regional boundary calibration to obtain vertex chain code and coordinates of boundary point, an algorithm has been inferred for particle size, sphericity and roundness, and problem-solving process for geometrical characteristics has been confirmed by experiments. The results indicate that measurement of geometrical characteristics, algorithm and analysis for the sizing and averaging have become rationale for the particle pattern recognition and analysis system. The conclusion breaks through traditional sieving methods in measuring and contrast plate method, laying foundation for the application of computer image analysis technology.

Abstract: This paper presents a novel sub-pixel corner detection algorithm for camera calibration. In order to achieve high accuracy and robust performance, the pixel level candidate regions are firstly identified by Harris detector. Within these regions, the center of gravity (COG) method is used to gain sub-pixel corner detection. Instead of using the intensity value of the regions, we propose to use corner response function (CRF) as the distribution of the weights of COG. The results of camera calibration experiments show that the proposed algorithm is more accurate and robust than traditional COG sub-pixel corner detection methods.

Abstract: For the existed river channel terrain measurement method defects such as complex measurement process and high performance equipments requirement, in the paper a terrain measurement method based on binocular vision is proposed. Firstly, in proposed system binocular vision measurement parameters are calculated on the basis of monocular calibration; secondly, artificial signs are located in river channel and detected based on improved Harris corners detection algorithm; thirdly, the feature corners in binocular images are matched based on epipolar constraint and SIFT algorithm; finally, for corrected images feature corners location method is proposed, and the river channel terrain is measured. Experiments show that in the proposed method the river channel terrain can be measured accurately, and the method has good reference value to measure other irregular scenes.

Abstract: Intermittent fault is the main factor for the raise of false alarm during the process of the detection in built-in test (BIT). Two-state Markov model and three-state Markov model for test is built for system fault diagnosis with BIT. According to the application of BIT in some complex system, a comparison of the false alarm rate between two-state Markov model and three-state Markov model is present, which shows we can reduce the false alarm rate (FAR) and improve fault detection rate by using three-state Markov model in BIT.

Abstract: In semiconductor industry, carrier concentration of a semiconductor material needs to be measured. Theoretical computation is complex and has its limitation. Experiment measurement always needs complicated and expensive instruments. Here, a new method for measuring the carrier concentration of silicon wafer was put forward. The dependen curve of thermoelectromotive force on temperature was graphed. The results showed that when temperature is below 460K, thermoelectromotive force is proportional to temperature of the hot probe. With the help of Origin software, slope of curve was obtained.Accoeding to related formula,the doping concentartion and it’s uniformity were figured out finally .Compared with other similar methods, this method is more simplified and thet equipment is cheaper.

Abstract: Test points choosing are the beginning of optimization of design for testability. With the consideration of uncertain influences on the tests of electronic equipment, the model for design for testability was proposed based on hybrid diagnosis modified by Bayesian network. Based on the new model, the algorithm of MBQPSO was proposed, which could take use of multi-dimension searching mechanism to choose test points according to uncertain correlation matrix between failure modes and tests. With the experiment, the result of this proposed method is closer to the reality and can provide better guidance for future design for testability.

Abstract: In order to establish a larger sensing area (10m×10m) and perform higher precision of the measurement system during barrel weapon test of vertical target dispersion, an optical detector is provided additionally in acoustic array to form a new measurement model, which does not only have the advantage of large sensing area, but also of higher precision. The paper presents and gives the measuring formula of the measuring model, and provides analysis on the measurement error. The simulation result showes that the errors of x and y Coordinates are 5mm and 15mm respectively.

Abstract: Based on laser triangulation measuring principle, a non-contact precise measurement method is proposed to get the spatial axis position of the large hole parts. According to the method, the measurement system is designed and the measuring mathematical model is founded. The fitting curve of the scanning profile and the space equation of the central line are obtained by least squares method. Besides, the errors of the measurement system are analyzed and corrected. The spatial position of the central axis could be quickly obtained by the method.

Abstract: Choose data Mining to study the anomaly detection in coal preparation, using ash of raw coal , rapid ash and yields of raw coal which density below 1.45, and ash and actual yields of fine coal in the database as sample attribute of coal production anomaly detection model, based on Box-plot analysis, the evaluating values range of five attribute above are determined. On this condition, by using SVM and KNN, the identification model of anomaly detection in coal preparation is established. The Receiver Operating Characteristic curves analysis result shows judging production target Abnormal Conditions using SVM will be more accurate in coal preparation.