Advanced Materials Research Vols. 1061-1062

Abstract: In this paper, the mathematical model of unmanned gliding-hydrofoil craft’s maneuverability is established by parameter identification theory. The objective function is established based on the data obtained in the experiment in towing tank. Two kinds of identification programs that genetic algorithm(GA) and particle swarm optimization(PSO) are written based on MATLAB. Each parameter of the objective function is identified based on the two programs respectively. The feasibility of the mathematical model is manifested by comparing the results of identification with experimental data. A full analysis and comparison is performed at the optimize efficiencies of the two programs.

Abstract: In the process of using the genetic algorithm for grillage structural optimization, direct calculation was applied to grillage structural strength Check. The combination of genetic algorithm and direct calculation can save significant time in optimization design and strength check, at the same time, optimized grillage structure provides more security.And then this structure optimization scheme was programmed by VB with easy interface. The example indicates the program, being reasonable and feasible, proves the combination's superiority.

Abstract: The numerical study of the influence of the ambient pressure of the fuel tank on the inerting effect of an aircraft fuel tank inerting system was carried out. The mathematical model of ullage equilibrium oxygen concentration has been established using the differential time calculation method based on the mass conservation and ideal gas state equations. The variations of ullage oxygen concentration and dissolved oxygen concentration in the fuel with time under different working conditions have been obtained. The results have shown that the as the ambient pressure of the fuel tank became lower, the speed of the decreasing of oxygen concentration of the fuel tank ullge and the dissolved oxygen concentration of the fuel was slower.

Abstract: We present a quantitative model, called metric hybrid automata, for quantifying the behaviors of complex physical systems, such as chemical reaction control systems, manufacturing systems etc. Due to the introduction of a metric, the state space of hybrid automata forms a metric space, in which the difference of states can be quantified. Furthermore, in order to reveal the distance of system behaviors, we construct the simulation distance and the bisimulation distance, which quantify the similarity of system behaviors. Our model provides the basis for quantitative analysis for those complex physical systems.

Abstract: In five-axis tool path planning, interference between the cutting tool and parametric surface is very critical. One way of doing interference detection is first to discretize the surface. In this article we develop a new approach to discretize parametric surface adaptively by applying curvature sphere. Layer by layer the original surface is discretized into triangle meshes bases on the polyline between the triangulated and un-triangulated areas of the surface. Triangles generated with our method are adaptive, which means the density of the triangles changes with the local curvature value of the surface. We also develop a method to deal with triangle meshes overlapping problem. So triangle meshes generated with our algorithm is without gaps or any overlapping problem. Finally a criterion is suggested when the generation should stop. The algorithm has been tested for some parametric surfaces and the result turns out to be satisfactory.

Abstract: Nowadays, the event-related potential (ERP)-based spelling device, often referred to as P300-Speller, is the most popular Brain-computer interface (BCI) which can provide a new communication path between patients suffered amyotrophic lateral sclerosis (ALS) with the outside world. At present, there are various P300 paradigms for P300-Speller, but no matter the accuracy or the speed cannot be supplied in our daily life. In this paper, an experiment based the two paradigms was proposed and operated to figure out which paradigm is much better between single display (SD) paradigm and region-based (RB) paradigm. 5 naive subjects participated the experiment and concluded that SD-Speller is superior to RB-Speller when the ISI was set 150ms. This result provides relevant theoretical basis for designing better graphical interface based on BCI.

Abstract: To address the calculation of elliptic sphere form error, a differential geometry algorithm is proposed and the presented model is answered by fminsearch function in Matlab. An example shows the effectiveness of the proposed algorithm.

Abstract: According to the standard definition of cylindricality error, set up any space surface cylindricality errors of least squares mathematics model. The coordinate origin of the model can be freely selected, nor equal angle interval among discrete sampling points. Analysis by computer simulation, results show that the model developed is right and pratical. On the basis of mathematical models, using four direct algorithm for unconstrained optimization, cylindricality errors can be evaluated in accordance with the minimum conditions. Mathematical models can be used for three-coordinate measuring machine and also available for other intelligent instrument for measuring parts of the cylindricality errors.

Abstract: With the rapid development of petroleum industry in China, the electrical heat tracing becomes very important for viscous oil transportation, while the heat insulation acts as the key to the application of electrical heat tracing. Rigid polyurethane foam has been widely used in long-distance pipelines for its advantages as the heat insulation material. However, there is also a lack of systematic analysis on the impact factors of such material, thus it is urgent to find out a practical method to distinguish the major impact factors. This paper introduces the Grey Relational Analysis (GRA) with its C# program, and it is proposed to analyze the actual impact factors of rigid polyurethane foam. The application shows that this method is practical, simple, rapid and accurate, so it suitable for similar applications in other fields.

Abstract: It is a large challenge to enhance Super Peer (SP) capability in the unstructured distributed system. The current study of this issue is still focused on how to choose a single peer as a SP based on some standards. Though the selected peer has the certain ability of tolerating the higher load, it is short of Scalability and reliability when the load increases dramatically. In order to improve the SP in these two areas, a new method, which uses Virtual Super Peer (VSP), is proposed. Based on the load in a cluster, one or several peers are selected as a SP. During running the system, the number of peers is dynamically adjusted as the load change. The experimental results demonstrate the method is effective in enhancing SP’s scalable and reliable performance.