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Beijing, China

Lv C.,Beijing Institute of Technology | Song R.-C.,Beijing Institute of Technology | Wang J.-B.,Unit 63961 of PLA | Liu J.-J.,Unit 61741 of PLA | He G.-L.,Beijing Institute of Technology
Binggong Xuebao/Acta Armamentarii | Year: 2012

Using simulation test method to evaluate the performance of fuze is very helpful to reduce the cost of fuze and also speeds up the fuze research and development. Equivalence of simulation test method and real artillery launch test is a criterion to decide whether the test results are reliable. Fuze inertia arming device is taken as an example. Firstly, an equivalence criterion was proposed according to its working principle. Secondly, a mathematical model of fuze inertia arming device was established. Thirdly, a software simulation of the dynamic response of fuze inertia arming device in a series of simulated artillery launch environments and the real artillery launch environment were accomplished. At last, the simulation data analysis proved the feasibility of equivalence.

Zhai Y.,Beijing Institute of Applied Meteorology | Zhao R.,Unit 61741 of PLA
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2016

Linear moment is one of the important methods to estimate the extreme value distribution function in engineering practice. In order to improve the estimation performance for Gumbel distribution, the estimating results of twelve empirical distribution functions were simulated by using Monte Carlo method. The optimal linear moment estimation method was constructed based on the empirical distribution function with the minimum estimation error, and compared with ordinary moment, traditional linear moment and maximum likelihood method. The study shows that choosing an appropriate empirical distribution function can enhance the estimation accuracy. The optimal empirical distribution function varies depending on the sample size, and its result is quite satisfactory in most cases and offers the best among the other methods especially in the sample size of 1 000~10 000. © 2016, The Editorial Board of Journal of System Simulation. All right reserved.

Zhao R.,Unit 61741 of PLA | Zhai Y.,Beijing Institute of Applied Meteorology
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2015

The generalized Pareto distribution (GPD) is a good probability distribution model to describe peak-over-threshold (POT) series, but the determination of its threshold is a great challenge in practical application. To solve this problem, we herein describe a Pickands bootstrap moment method for estimation of the GPD parameters. The method is used to estimate the shape parameter of GPD and the optimum number of POT and calculate the threshold, then the scale parameter is obtained with the moment estimation method. This new method is applied to the daily precipitation series of the Beijing meteorological station and its results are compared with those estimated by the linear moment estimation method using the same threshold. The comparison shows that it has a good ability of parameter estimation for GDP and generalized extreme value (GEV). From the fitting of the GDP quantiles and POT series, their correlation coefficients are up to 0.997 or more while their standard deviation and maximum deviation are the lowest. These results indicate that the Pickands bootstrap moment estimation method is obviously superior to the linear moment estimation. © All right reserved.

Zhao Y.-M.,Unit 61741 of PLA | Li J.,Unit 61741 of PLA | Meng L.,Unit 61741 of PLA | Zhao Y.-C.,Unit 61741 of PLA
Binggong Xuebao/Acta Armamentarii | Year: 2013

Sea clutter is the main factor affecting the radar target detection, but the marine atmospheric environment changes the sea clutter characteristics by influencing the electromagnetic wave propagation path. The cause of sea clutter characteristic difference is analyzed in the different atmospheric environments, and the empirical model is used to establish an algorithm of sea clutter characteristic quantity based on the "opposite distance" method. The real sea clutter characteristics are simulated with the experiment data in Ref.[9]. It is found from the comparison of the datum observed in four directions that the simulation value is agreement with the measured average value. Finally, the sea clutter characteristics in standard atmosphere, evaporation duct and surface duct environment are investigated by using the simulative environment conditions and radar parameters. And the results show that, compared with the standard atmosphere environment, the sea clutter characteristics show a trend of increase in the duct environment, and the first skip zone in the surface duct environment also presents weak clutter or no clutter.

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