Applied Mechanics and Materials Vols. 513-517

Abstract: Hopf bifurcation occurs in most of dynamics systems when the influence from the past state varies. In modeling population dynamics, it is more reasonable taking into account the time delays. In this paper, a stage-structured predator-prey system with delay is considered. The existence of Hopf bifurcations at the positive equilibrium is established by analyzing the distribution of the characteristic values. An explicit algorithm for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form and the center manifold theory. Numerical simulations to support the analytical conclusions are carried out.

Abstract: In order to simulate growth and development process of tree, then provide services for production management and scientific research, all kinds of tree growth models are constructed. The paper firstly considers a variety of factors affecting the growth and development of tree, then studies artificial intelligence knowledge such as neural network and expert system, uses the neural expert system to solve the acquisition and management of tree growth parameters, and design and develop tree growth management and expert system based on growth models, the models combine morphogenesis model of tree and knowledge model to provide comprehensive environmental control and management decision-making. Practice has indicated that the growth models of tree can reflect the growth of trees under different physiological and ecological conditions, and visual effect is very good.

Abstract: The interests of project participants are the core of collaborative. These participants such as proprietor, construction unit, subcontractor, supplier, government carry out the new management model of large span integration for maximizing their own interests. It is not only the inherent law of contemporary management development, but also an actual requirement raised in realizing the project benefit maximization. So the research of synergy model in the application of project management has important theoretical significance and practical value. The article puts forward related theory of synergy management, uses the basic thoughts of public opinion model, analyses the trend of subject selection decisions which is the feasibility of the actual implementation of synergy management mechanism, and finally builds synergy management mechanism model.

Abstract: . Aiming at the disadvantage of the variable step size LMS adaptive filtering algorithms' convergence speed contradicting its steady-state error, a novel non-liner functional relationship between μ (n) and error signal e (n) was established. On the basis of the functional relationship, a new algorithm of variable step size LMS adaptive filtering was presented. The step size factor of the new algorithm is adjusted by the absolute value of the product of the current and former errors. It also uses the absolute estimation error compensation terms disturbance to speed up the convergence of adaptive filter tap weight vector. At the same time, the algorithm considers the relationship between step length of the last iteration and the former M error signal. As a result the algorithm has higher convergence characteristic and small steady state error. The theoretical analysis and simulation results show that the new algorithm has faster convergence speed, lower steady state error and better performance of noise suppression, also show the overall performance of this algorithm exceeds some others condition.

Abstract: The aim of this study was to investigate the use of the least squares regression and integer programming as a method of defining optimal sampling area for monitoring large-area crop rotation period. It was found that using this method significantly decreased the cost for monitoring large-area rice-cotton rotation by 84% and increased only the monitoring error by 4%. This new method demonstrated potential for general applicability to monitoring other large-area crops.

Abstract: According to the problem such as blurred border of images and lower efficiency caused by present interpolation methods, an interslice interpolation based on the relativity for medical image is presented in this paper. This algorithm makes good use of voxel relativity and structure relativity and then the different methods are adopted to interpolate the different points, In addition, error checkout is introduced to check the mismatching points.The experiments show that the proposed algorithm has less computational complexity and improves the quality of image, at the same time, the result can be used to 3D reconstruction effectively.

Abstract: The traditional segmentation method for medical image segmentation is difficult to achieve the accuracy requirement, and when the edges of the image are blurred, it will occurs incomplete segmentation problem, in order to solve this problem, we propose a medical image segmentation method which based on Chan-Vese model and mathematical morphology. The method integrates Chan-Vese model, mathematical morphology, composite multiphase level sets segmentation algorithm, first, through iterative etching operation to extract the outline of the medical image, and then the medical image is segmented by the Chan-Vese model based on the complex multiphase level sets, finally the medical image image is dilated iteratively by using morphological dilation to restore the image. The experimental results and analysis show that, this method improves the multi-region segmentation accuracy during the segmentation of medical image and solves the problem of incomplete segmentation.

Abstract: According to the process of the ECG signal extraction, the ECG signal is susceptible to interference which will affect the quality and effect of ECG test. In this essay, we designed an ECG signal filtering system based on ARM. It can filter the interference signal and reduce the interference of the common mode signal and power frequency, through the design circuit of the preamplifier, post amplification, filtering, notch filtering, and power amplification. Thus, ECG signal will be better collected and met the best demand.

Abstract: Image data set are usually very large, which might consist of millions of image objects, it is essential to use an efficient and effective indexing technique to facilitate speedy searching. The features can be expressed in terms of high-dimensional vector data which can be compared with a given query for similarity between them. It is more important that the image database should be preprocessed and establish indexing to improve retrieval efficiency. In this paper, the method of improved X-tree is proposed, design and implementation of a high dimensional index application to facilitate the speedy searching in feature based image information retrieval. Compared by retrieval efficiency and retrieval result, it is convincingly proved that hierarchical index structure based on clustering is efficient and applicable in image characteristics indexing.

Abstract: Tax treaty signed between countries can solve the problem of the crossing of tax right, adjust the international double taxation, prevent transnational tax evasion, resolve the international tax disputes, promote cooperation with other countries. This paper analyzes the influence of overseas direct investment based on signed the tax treaty.