Applied Mechanics and Materials Vols. 543-547

Abstract: This paper discusses the calculation method of Gauss Curvature on space mesh points in simplified level-of-detail (LOD) model technique and how to program with C# language at the platform of .NET. Then, with this algorithm, get the curvature value of the mesh points, delete the center point of the small curvature and triangularize the cavity left so as to realize the simplification of the LOD model. In order to show the result of this algorithm, this paper visualizes the LOD model of the three-dimensional terrain model in full detail with Gauss Curvature Algorithm, puts forward the idea of carrying out error analysis on the algorithm with the geometric property of curvature, and compares the result with that with other algorithms. All the example and the error analysis show that this algorithm is not only of fast speed but also with good effect.

Abstract: In recent years the research on structure and efficiency mode of farmland shelterbelt are more, while the prediction models of the poplar are much less. The growth model is based on poplar growth and management, the development of information technology provides new methods for the research and evaluation of poplar growth model. All kinds of information technology are used to extract growth character parameters of poplar, and neural network and expert system is used to establish the relational models of the character parameters and production management of poplar, these models are used to provide the basis for the cultivation of poplar growth and management, which have important theory value and practical significance.

Abstract: Based on the uncertainty of covariant matrix and value of expected return in risk assets, constraint tracking error for investment portfolio optimization model of VaR in additional transaction costs is constructed in this paper. The validity is proved by using the method of linear matrix inequality. According to empirical analysis, the results of different investment models are analyzed and compared with the one gotten by the method in this paper. It is concluded that the distribution of weights of the model in this paper is more reasonable and its final return is better than other models. Moreover, it may be closer to the modern financial markets for its transaction cost.

Abstract: In the process of comprehensively evaluating multi-object and making decision, the evaluation method is an important factor that leads the evaluation results. In this paper, we discuss a subjective and objective comprehensive evaluation method based on AHP and rough set, by using which, the weight is determined and the comprehensive weight of the attribute is calculated. Then the data is analyzed by weighted method to obtain the overall ordering results. Finally, we analyze practical examples by the implemented program and verify the effectiveness of the proposed approach.

Abstract: The cuckoo search (CS) algorithm is a very efficient swarm optimization algorithm. Based on CS, a cuckoo search algorithm based on dynamic grouping to adjust flight scale (DGCS) is proposed: All cuckoos are divided into three groups according to the fitness of the individual and the average fitness of the population, then different flight scale is adopted dynamically for each group. Simulation experiments show that the DGCS can quickly converge to the global optimum solution, and has better optimization performance.

Abstract: in the field of artificial intelligence, Case Based Reasoning (CBR) is an arising reasoning technique, in which choosing reasoning index has been the hot topic and difficulty. In order to get optimal feature subset in the process of index selection, this paper combined gray correlation analysis with genetic algorithm (GA) to optimize the feature selection process, taking the gray correlation analysis result as the initial population for GA heuristic search, which can on one hand get better feature combination, on the other hand, effectively reduce the evolution of GA, finally improving GAs execution efficiency. Based on this, an optimized GA-CBR case reasoning model is put forward, which has been proved by empirical results to have an improved CBR forecasting accuracy.

Abstract: To enhance the ability of the standard Particle Swarm Optimization (PSO) on solving the complex nonlinear problems, an improved algorithm with independent inertia weight for each particle was proposed in this paper. Firstly, a single particle of the particle swarm was studied. The law of the instantaneous movement of single particle at each iteration was analyzed in a novel geometric view. Two importance conclusions were drawn: 1) The introduction of the two random numbers makes the particle search in a broad parallelogram area, while the product of the inertia weight and the particles present speed is the parallel shift of the aforementioned parallelogram area; 2) The search ability will be greatly reduced as soon as a particle becomes the Global Optimal Particle (GOP). Then, on the ground of the significant conclusions, the improvement plan of the standard PSO was put forward. Experiments show that the proposed algorithm has obvious superiority on the convergence ratio, the convergence speed and the convergence stability.

Abstract: This paper proposes a corrected shooting method for a general non-linear system with impacts. We define the global Poincaré mapping for period orbits by the discontinuous mapping. It is suitable to construct the strategy of shooting method. As an illustrated example, we investigate the stability of period orbits in a Duffing system with impacts. In Addition, coexistence of attractors and bifurcations for period orbits are considered.

Abstract: It is known that the level of the consistency-order of initial value problem is an important standard to determine whether the constructed methods for solving initial value problem of ODEs is suitable or not. There are two methods to solve the consistency-order of initial value problem in general. The one is using the remainder of integral formula as local truncated error, and the other one is using absolute error as local truncated error. In the paper, we propose a novel method based on Gauss-Legendre quadrature formula. It use the method of the remainder of integral formula as local truncated error exists in most of the literatures, and it will be solved once again for the consistency-order of the constructed methods that exist in currently literatures by using absolute error as local truncated error, and then draw a conclusion that is differ from what has been proved correspondingly.

Abstract: Discrete event system is driven by event, and system status is discrete on time and space, so it is difficult to solve by using equation model and theoretical analysis method. Computer simulation technique provides an effective mean in order to solve these problems. Contents of this study provide technical and methodological support for computer simulation of discrete event. Firstly, the paper illustrated the basic concept of discrete event system; then, time step method mechanism described by mathematical model and graphical method; finally, we can research on the control flow of event step method when it promotes simulation, and then describe the three scanning methods of event step method, the first is clock value of type event; the second is clock value of dominant entity; the third is event tables. The result showed that the simulation model constructed by event step method has the advantages of short running time, the implement of program easily and so on.