Papers by Keyword: Statistical Characteristic

Abstract: Loss of gray level is a usual phenomenon in tone transformation of digital image. In order to improve the effect of tone transformation, original image is segmented into blocks, which consist of some pixels. In tone transformation, average value of gray levels, which belong to the pixels of every image block, is computed. According to the different average values of image blocks, different curve for the tone transformation is selected and the pixels of the block are processed correspondingly. If the transformation curves for the processing are enough, the loss of gray level is relative fewer. Although some of the gray levels of different image block are lost, but the lost gray levels of different image block are disperse and are not always coincident. Therefore, compared with the tone transform with one single curve for whole image, the loss of the gray level in image, which is transformed with block-segmentation and with different curves, is much fewer and the quality of processed image is relative better. The principle, as well as the algorithm is described, and the results of processed images are analyzed.

Abstract: Aiming at the image process demands, a kind of image matching recognition algorithm based on statistical characteristics of the image after wavelet transform was proposed. This algorithm adopts wavelet to perform multiple scale two-dimensional wavelet transform for image. The corresponding progeny images energy distribution in different direction and different scale will be taken as statistical characteristics. The targets to be recognized can be identified through the angle's cosine value between the extracted statistical features from the targets and the statistical characteristics of the standard library image. Finally, the bar codes of books are adopted to verify this method and the results show that the algorithm has good recognition effect for the different characters in bar codes.

Abstract: Based on the experimental result of the flexure capability of reinforced concrete beams strengthened by carbon fiber sheets, the stress distribution changes only after steel yielding and carbon fiber sheets function better. However serious the extent of the damage is before strengthened, the tensile strain of main steel reaches about 1.6 times of the yield strain for the secondary grade of steel as failure happens. To satisfy the object reliability indicator, reliability is analyzed using the ratio of the steel strain at the balanced failure to the yield strain as variable to obtain its optimum value, which is coincide with the experimental result, and makes better consistency between calculated reliability indicator and object reliability indicator.

Abstract: Based on the experimental data of mechanical performance of carbon fiber sheets, the statistical characteristics are obtained by symbolic statistical method. The characteristics of flexure capability of strengthened beams are established with a certain ratio of the strain of CFS to its ultimate strain for the failure due to the rupture of CFS by Monte-Carlo method. Reliability taking the aboved ratio as variable is analyzed to obtain its optimum value, on the basis of which the lower limit of CFS is decided that makes better consistency between calculated reliability indicator and object reliability indicator.

Abstract: Road transportation accidents of dangerous goods occur frequently. These accidents destroy and pollute the environment seriously, cause huge economic loses and endanger the safety of people's lives and property. 233 cases of road transportation accidents of dangerous goods which occurred during January 2008 to December 2010 were collected in this paper, accompanied by classified statistics and detailed analysis, three countermeasures have been proposed: strengthening the transport of dangerous goods management under severe weather, focusing on the daily inspection and control, implementing accident prevention measures in important region and roads. The study of this paper has important practical significance on researching how to prevent the occurrence of such accidents.

Abstract: As the poor generability of special sensor support frame and the inconvenience of signal acquisition in the process of common fault diagnosis for cracked rotor, a new fault diagnosis method is presented in this paper. this method takes the basement of rotor test rig as the monitoring objects and makes feature fusion for time-domain statistics of multiple sensors using SVM (support vector machine). The result of experiment showed that the method using the multi-sensor signal fusion technology collected from the basement of machinery has the advantages of better diagnostic precision for rotor crack diagnosis, furthermore, it supplies a new way for rotor fault diagnosis.

Abstract: The surface micro-topography characteristics of micro-WEDM, which can have a directly significant impact on the parts usability properties, have been attached more and more importance by people. In this study, the method of statistical analysis is applied to work out the two-dimensional autocorrelation function figure and the power spectrum density function figure of the surface micro-topography of micro-WEDM. It can be seen that there are more sharp and narrow peaks and high frequency components, meanwhile, there are some low frequency wave components on the surface. A conclusion is arrived at that the three-dimensional (3D) surface micro-topography of micro-WEDM shows isotropy through analyzing its texture characteristics. The results can provide the theoretical basis for further establishing the appropriate evaluation parameters for the surface roughness of micro-WEDM.