Advanced Materials Research Vols. 926-930

Abstract: Air defense process of large surface warship formation is a very important part in the combat. In current research, however, less attention has been paid to the whole process of air defense of surface warship formation in macro perspective. This paper applies the PEPA method to model the air defense process of surface warship formation. The cooperation among elements has been taken into account in the established model and the basic process of the air defense has been described as well. By analysis it shows the performance of air defense of warship formation increases with the increase of elements’ quantity, and finally reaches a stable value. Then the composition of the basic formation elements that the interception capacity of air defense operation attains the maximum can be obtained from the test results. Therefore, it provides a new quantitative method to deal with the air defense problem of warship formation.

Abstract: This paper analyzes the restricted three-body problems in the ground test systems. First, under the ideal condition, after analyzing the forces on the spacecraft in the rotating coordinates, a mathematical model of elliptic restricted three-body motion is founded. Second, for the restricted three-body problem in the ground test system, the forces on the test ball are analyzed and the corresponding elliptic mathematical model apart from the perturbation is founded. Then, based on the two models founded above, the similarity between the ideal spatial model and the ground simulation model is analyzed.

Abstract: We discuss performance of queuing systems, particularly QuickPass system, as well as design optimal operation strategy to minimize the time cost of amusement park tourists. The paper consider that the time interval of the visitors' arrival is submitted to Nonhomogeneous Possion Process and the time of receiving service is submitted to exponential distribution. We gradually take account of different factors, and construct three models. We construct the basic model and design optimal operation strategy to minimize time cost function of amusement park tourists, and the second model with the fact that there are two queues in reality. Basing on the models, we simulate them and get expected results. At last, we analyze our models objectively and extend its use in other areas. The paper comes up with a standard to evaluate different models. Likely, we write a non-technical summary for amuse- ment park executives who must choose between alternatives from competing consultants.

Abstract: For multi-attribute decision making problems whose attribute values are ternary interval numbers and their weights and attribute values are not fully, this paper proposes a decision-making method based on the similarity degree of ternary interval numbers. Firstly, utilizing the closeness theory of fuzzy sets, we give the corresponding axiomatic definition of ternary interval numbers and obtain the corresponding calculation formula of similarity degree. Then, according to the basic idea of traditional TOPSIS method, we establish the multi-attribute decision making and give the general steps of solving multi-attribute decision making problems. Finally, the paper demonstrates the effectiveness and practicality of the method by the example analysis.

Abstract: Quench protection system is a necessary part in superconducting magnets design. Rational design of quench protection system requires understanding of heat transfer and electromagnetic process in the magnet during quench process. A multi-field coupling model was developed to study quench process. This model sequentially solves two different physics environments, one is thermal physics environment, and the other one is electromagnetic physics environment. This model was applied to simulate one solenoid magnet in practical engineering. The main parameters results during quench process were presented. This research enriches the theory of numerical simulation on quench process of superconducting magnet, and provides theoretical guidance for the design of quench protection system.

Abstract: This article analyzed the defects of SVM-RFE feature selection algorithm, put forward new feature selection method combined SVM-RFE and PCA. Firstly, get the best feature subset through the method of cross validation of k based on SVM-RFE. Then, the PCA decreased the dimension of the feature subset and got the independent feature subset. The independent feature subset was the training and testing subset of SVM. Make experiments on five subsets of UCI, the results indicated that the training and testing time was shortened and the recognition accuracy rate of the SVM was higher.

Abstract: Fractional diffusion equations have recently been applied in various area of engineering. In this paper, a new numerical algorithm for solving the fractional diffusion equations with a variable coefficient is proposed. Based on the collocation technique where the shifted Chebyshev polynomials in time and the sinc functions in space are utilized respectively, the problem is reduced to the solution of a system of linear algebraic equations. The procedure is tested and the efficiency of the proposed algorithm is confirmed through the numerical example.

Abstract: Booms have been widely used in protecting the coastal area in oil spills, but the ocean wave often causes the boom’s overtopping failure. The Smoothed Particle Hydrodynamics numerical method which has advantages in simulating the free-surface-flows and the fluid-structure interaction was used to study the boom failure in the wave. A 2D wave flume model was constructed to simulate the wave acting on the boom which causes the boom’s overtopping failure. The effect of deflection angle of boom was systematically studied. Through comparing the critical height range of wave that causes the overtopping failure of boom at different angles, the optimal angle range for the efficiency of boom against wave which is-40° to-60° is proposed. SPH as a utility method for simulating the fluid-structure interaction problem has exerted its effectiveness in learning the overtopping behavior of wave acting on the boom.

Abstract: Implied volatility is an important variable affecting the option price. In the B-S model, other factors can be obtained directly, but implied volatility is not directly. According to B-S model, build on the volatility equation, using Newton iteration to obtain its approximate solution and compare with the classical formula of demand volatility. The example shows that good results can be obtained.

Abstract: Based on engineering tests of rubble bed, numerical simulation of loading tests adopted discrete element software PFC2D was designed. The numerical model of rubble bed considering characteristics of shape, particle size, compactness and aggregate gradation was established, and then the engineering tests were reappeared by the means of applying continuous loading. The mechanical mechanism of rubble bed under continuous loading was analyzed based on comparison on stress-strain curve of engineering test with numerical simulation and the settlement and failure law of rubble bed under continuous loading were obtained. The work also discussed the effect of different compactness on bearing capacity of rubble bed and fitted the curve between compactness and bearing capacity, so it can be taken as a reference for analysis on loading compaction and bearing capacity of rubble bed.