Applied Mechanics and Materials Vols. 29-32

Abstract: Genes are classified in order to understanding the categories of animals and plants, and to getting the knowledge about their connatural structures in the research of the biology. It is important to use clustering methods to recognize and classify modes of gene expression data effectively for studying the relationship between different species of genes. In this paper, an improved algorithm for clustering gene expression data based on Minimum Spanning Tree (MST) is proposed. The improved algorithm mainly uses direct clustering and recursive calculation method to shorten the running time. According to the results of the experiments, Through the use of multiple data sets, the results show that the improved algorithm than the original algorithm is greatly increased in the running time.

Abstract: The propagation of elastic waves through a micro gap considering frictional contact is investigated in the present paper. Using the Fourier analysis technique and corrective solution superposition method, the problem is solved analytically. Special examples for identical materials are discussed in detail. The results show that the initial gap width has significant influences on the harmonics and energy partition and their relations may be effective on non-destructive evaluation of a pre-existing gap.

Abstract: A combined numerical model is proposed in order to solve ablation and denudation under high temperature and high pressure. Vortex method is used for simulating vorticity field and pressure distribution; a three-equation model is used for resolving the ablation mass loss; and a trajectory model is adopted for solving the motion of denudated particles. Compared with the flow past an ablating cylinder with the same Re number and ablation condition, the ablation effect on the sphere-conic is more significant and the vorticity contour turned to an asymmetric structure earlier; the particle traces are no longer symmetric, and the particles distribution become unorganized; the linear momentum of the ablating sphere-conic become larger than the non-ablating one; This simulation may offer numerical references to ablation experiments on thermal protection materials.

Abstract: Aiming at the layout problem of underprop equipments in constructing 3-D abnormal space, a Creating method of underprop project is presented in this paper. By analyzing the underprop equipment and the 3-D abnormal space, the optimization model is built for underprop equipments layout. An optimization approach of the model is advanced, then the underprop project is presented. At last, an underprop project is made based on the method in this paper. According to the project, a 3-D space can be built quickly.

Abstract: Adopted by IEEE802.11b standard as the high speed expanding scheme, CCK modulation technology performs well in error probability with high signal noise ratio. However, the CCK system’s error probability soars when SNR is comparably low or the number of users in the same channel increases suddenly. Based on CCK algorithm and convolution code’s structure, this paper analyzed code parameters’ influence on error probability and proposed a channel coding scheme suitable for CCK modulation: convolution code （2,1,7）with 3bit soft decision decoding. Simulation Results demonstrated that system performance is greatly improved when SNR is upon 1.3dB and 2dB’s additional coding gain is attained compared with hard decision decoding.

Abstract: The electrical method is effective on detecting and locating leaks in geomembrane liners for landfills. If a leak exists in the liner, an anomaly in the measured potential is generated in the immediate vicinity of the leak through which electrical current is flowing. But the power supply current above the liner can affect the potential distribution. A current point source model for power supply current was set up in this paper. The potential equation induced by the point source was derived. The analysis of potential expression shows that: 1) the potential generated by the power supply current is proportional to the current size and the medium resistivity; 2) as the medium thickness increases, the potential reduces; 3) to reduce the influence of power supply current, the power supply electrode should be away from the detection area as far as possible.

Abstract: Camera calibration establishes the relationship between 2D coordinates in the image and 3D coordinates in the 3D world. BP neural network can model non-linear relationship, and therefore was used for calibrating camera by avoiding the non-linear factors of the camera in this paper. The calibration results are compared with the results of Tsai’s two stage method. The comparison show that calibration method based BP neural network improved the calibration accuracy.

Abstract: It is necessary to take into account synthetically attribute of every index because of independence and incompatibility resulted from single index evaluating outcomes. Through the information entropy theory and attribute recognition model being combined together, attribute recognition model based on entropy weight is constructed and applied to evaluating groundwater quality by a new method, weight coefficient by the law of entropy value is exercised so that it is more objective. The outcome from concrete application indicates that it is suitable to evaluate water quality with reasonable conclusion and simple calculation.

Abstract: This paper reveals the concentration status of the construction industry in the 8 provinces of southeast China, its impact on the local communities, and proposes a tentative plan to stimulate local economy through industrial concentration based on the measurement and calculation of Gini coefficient in the 8 provinces and regression analysis of their population and output of steel and concrete.

Abstract: It is necessary for researchers to design lightweight authentication protocols to protect information security between tag and reader in RFID system. It is a great challenge to design an efficient and secure protocol because the tag has limited computation resource. In the paper, we firstly analyze some protocols. Secondly, we introduce a serverless authentication protocol for RFID system and analyze its security. We find it does not provide two-way authentication. Thirdly, we propose a modified two-way authentication protocol without server for RFID. The result indicates it provides privacy protection, resists tracking, and resists cloning attack. Moreover, it provides two-way authentication. For the efficiency, we think the computational complexity of our protocol is at the same level with the original protocol.