Key Engineering Materials Vols. 474-476

Abstract: With the development of Internet technology, online education colleges and companies have developed a WWW-based distance education system. The traditional examinations are moving towards online exams based on Internet. With the development of computer technology and the increasing popularity of computers, online examinations are gradually becoming matured. Traditional test methods have been unable to meet current test demands. All aspects of traditional test can be reduced to one or two links by Online Examination, greatly reducing the workload of teachers. This paper discusses the framework of the system, jsp technology and its working principle. Due to the shortcomings of traditional test methods, the objective, impartial, scientific and rational Online Examination system has a large reference value.

Abstract: In this paper, We apply option game theory methods to compensate for the inherent limitations of traditional NPV, study Timing Decision of recycle economy investment in monopoly situation, in best time to invest the recycle project, not only brought a lot of cash flow, better profitability, and implemented the project cycle of production, reduce production costs. Finally ,analyze the parameters of affecting investment , which can reduce the impact on investment；And analysis the difference in critical belief value between the project investment of recycle economic and non-recycle economy. CLC：F424.7 Document code：A

Abstract: Non-uniformity of infrared focal plane arrays (IRFPA) decreases the quality of the infrared imaging system greatly, so it is necessary to correct non-uniformity. Now the scene-based correction is being the focus of the study at home and abroad. Firstly, researching on normalized BP artificial neural network correction method in this paper, and then building a SOPC system on Altera's Stratix II EP2S60 DSP Development Board to realize the normalized BP real-time correction non-uniformity. The simulation results show that the SOPC system would meet the requirements of real-time correction. At the same time, the other method could be better to upgrade.

Abstract: Wireless sensor networks(WSNs) which develop steadily and fast became the most popular technology at the beginning of the 21st century and would have a good influence on the world for a long time, but at present most of the study are mostly focus on the theory of algorithm for network topology, routing, location etc., however the real world needs real devices, and at the same time the device must meet the needs of practical applications, so, according to the various structural features of the wireless sensor networks, a new design with ZigBee protocol based on the System-on-Chip (SoC) chip of CC2430 for wireless sensor nodes is proposed. We emphasize the circuit design and the process of system initialization, we use the humidity and temperature sensor SHT10 to meet the low-power cost of the system. Finally, we tests the compact design of the node with SHT10, which has an excellent performance and stable operation with good extendibility.

Abstract: The article focuses on analyzing plastic deformation and microstructure evolution mechanism of foam aluminum material when foam aluminum is compressed and stretched uniaxially at room temperature, and studying plastic deformation of foam aluminum at room temperature and high temperature. Results show that cold forming of foam material is restricted by many factors. So, it only carries out some simple integral forming and local plastic forming; High temperature reduces the yield stress and deformation limits of foam material, that the forming can be easily carried out. If parts of TiH2 foam aluminum are processed, the temperature must be below solidus temperature in order to avoiding destructing pore structure.

Abstract: In order to improve the utility of infrastructure of high speed railway, it is very important to manage the capacity. This paper analyzed the characteristics of high speed railway capacity from a few points of view. Then, it proposed a method of capacity calculation and capacity consumption assessment respectively. Decision support system called CRH-CMS is developed. The use of field data proves that the model is effective and the system is practical to use.

Abstract: In the analysis of social network, the attribute values of an entity change constantly as time goes by and the corresponding attribute graph changes accordingly. However, the essence of the entity is invariable. The problem is how to discover essence from the change of mining frequent rough matching attribute sub-graph in an attribute graph in this paper. The problem of the attribute sub-graph rough matching is defined and described, then the random walk rough matching algorithm of attribute sub-graph is designed so that the problem of incomplete coincide attribute sub-graph rough matching would be solved. Attribute sub-graph is the expansion of the traditional sub-graph; rough matching problem is the extension of traditional sub-graph matching problem. With the help of the random walk rough matching algorithm of attribute sub-graph, more potential frequent attribute sub-graphs can be discovered, and more valuable information mined.

Abstract: According to the multi-contact solving problems of the mechanical system dynamics simulation software ADAMS, solving contact and influence of parameters setting on the results were studied based on the viscous damping theory. Researches focused on how the maximum damping coefficient affects the results of the system contact simulation in contact-solving process by connecting theory and practice. It provides some theoretical basis and practical experience for the study of multi-contact problems and had a certain amount of guidance on the multi-contact solving problems.

Abstract: A series of time lag taches result in miss-distance lag in the coarse tracking system of APT system, which will greatly influence the tracking precision of the whole FSO communication system. In order to provide theory basis for determining the sampling frequency and components with time lag character, the influence on systems stability resulted from phase margin loss caused by miss-distance lag is analyzed in detail. To eliminate the influence caused by miss-distance lag, finite memory based τ Compensatory Technology is put forward, which has characteristics of simple program realization, low CPU overhead and high precision, experiment result shows that miss-distance lag based on τ Compensatory Technology is feasible and effective to practical APT system.

Abstract: In this paper, apply option game theory methods compensate for the inherent limitations of traditional NPV, derived the optimal preempt invest cycle economic projects critical value and the expression of the value function in under incomplete information oligopoly competition, give investors the preempt investment strategy rules, and analyze the relationship between critical value of investment and risks rate. Research shows that the larger face risk of being the first to competitors, the more investors will invest earlier. CLC：F424.7 Document code：A