Applied Mechanics and Materials Vols. 229-231

Abstract: For problem of feature modeling on halftone image, three statistics methods, named gray-level co-occurrence matrix, autocorrelation function and spectrum statistics, are used to extract feature vector of various halftone images. Then, their classification performance is assessed by radial basis function neural network. A mass of experiments show the autocorrelation function is better than other two methods for classification on halftone image.

Abstract: The distributing flow system with slide valves is generally used for nitrogen-inflating hydraulic beaker, but it has some main bad problems. To solve these problems, a new distributing flow system was designed by applying the technology of screw-in cartridge. Then, the system mathematical model for the hydraulic breaker was proposed, and the performance of hydraulic breaker was analyzed by simulation. The simulation results show the principle of the distributing flow system designed is correct and feasible, moreover established mathematical model is accurate and reliable. It provides a viable technical approach and theoretical reference for the development of high-performance hydraulic breaker.

Abstract: The elastic stress field theory is used to research the quantitative relation model between ultrasonic pulse-echo and layer structure when ultrasonic wave is vertical-incidence transmission, and numerical simulation has demonstrated the models are available.

Abstract: By using a computer vision detection system to obtain high resolution images of a machine part, a kind of reverse design method of solid modeling of irregular planar part with aided implementation of computer vision was proposed in this paper, which integrates image processing function of Matlab software with solid modeling function of computer aided design (CAD) software. The method used a calibrated digital camera to get the image of the tested part, a three-dimensional entity vector model may be built up after image inversion, edge detection, vectorization process of binary image and size matching were operated sequentially. The results of image reverse design showed that it is an easy and convenient way to reverse irregular planar parts based on image processing. One of its remarkable advantages is the saving of design period and the reduction of design cost. Its measurement error can be controlled within 0.1 mm, and can meet general precision requirement of application occasions. Reversed parts may provide a model basis for further analysis on mechanism assembling and motion simulation.

Abstract: Road traffic safety is a major security problem faced by our society. It has great significance for the society to give the driver a safety education in the totally immersed virtual reality environment. With the single channel stereo display projection system, we established the road traffic safety education system, and solved some key issues, such as the physical modeling of immersive driving experience, the vehicle dynamics simulation and so on. Practical application shows that the system has achieved the purpose of road traffic safety education.

Abstract: A number of image filtering algorithms based on nonlocal means have been proposed in recent years which take advantage of the high degree of redundancy of any natural image. The block-matching with 3D transform domain collaborative filtering (BM3D) proposed in [1] achieves excellent performance in image denoising. But the choice of shrinkage operator in block-matching step is not discussed, only given the threshold by experience in its related papers. In this work, we introduce an improved version of BM3D with adaptive block-match thresholds. The proposed method firstly seeks the relationship between the Structural Similarity index (SSIM) [2] and match distance in blocks and obtains the data with fine SSIM values. Then, compute the Noise level and Gradient values in blocks of the same block size. Finally, surface fitting is adopted to get a formula which applies weak thresholds for flat blocks and strong thresholds for detail blocks. Experiment results are given to demonstrate the same class of denoising performance with less time-consuming to slightly noisy image and good improvement in denoising performance to seriously noisy image.

Abstract: For better study of the airflow movement in the untwisting chamber of a pneumatic splicer, this paper uses a commercial computational fluid dynamics software FLUENT to realize the three dimensional numerical simulation for the characteristic of the airflows in the untwisting chamber. A three-dimensional grid and the realizable k- ε tur¬bulence model are used in this simulation. The characteristics of the air flows in different parts of the chamber are analysed according to the computed result. The airflow in the untwisting chamber can be divided into three regions in longitudinal section and two regions in cross section.

Abstract: The model of the airbag deployment test has been established based on U.S. FMVSS 208 regulations, and the effect of the protection of PAB’s two folding patterns on out-of-position child occupants has been tested. The Experiments show that the "Z" shaped folding is better than the winding folding according to the experiment model. In addition, optimize the airbag by the method of expanding the size of pores and the horizontal size of the airbag to achieve better protection for out-of-position child occupants.

Abstract: In water production-reinjection system, a spiral solid-liquid separator is installed at the inlet of the electric submersible pump (ESP) to prevent solid materials in the re-injected water from plugging formation pore and keep the efficiency of water injection. In order to determine optimum structural parameters and operating parameters of the separator, numerical simulation was conducted to analysis the effect of spiral laps, spiral pitch, inlet velocity, etc. on separation properties. By analysis and comparison, spiral laps of 5, pitch of 18 mm are the most suitable structure parameters. In operating parameters, the pressure drop and separation efficiency increase with the inlet velocity increasing. The results provide reference for further research of the spiral solid-liquid separators.

Abstract: This paper analyzes structural features of the prolog compiler on the basis of its executive mechanism. The main focus of the research targets the functional characteristics and the working mechanism of the compiler through the analysis of prolog language organizing and translating procedure in conjunction with the logic-reasoning attribute of the language. The paper illustrates structure of three important modules and demonstrates their corresponding realization method. The research of lexical compiler will lay a foundation for future works of upgrading and developing Prolog compiler.