The Implications of Krashen’s Second Language Acquisition Theory on College English Teaching

Krashen's second language acquisition theory consists of language input theory,emotion filtering theory and languageoutput theory.In order to apply Krashen's second language acquisition theory to college English teaching,it is suggested to commence from the acquisition and learning theories to optimize the teaching environment and methods.On the basis of language input theory,emotional filtering theory and language output theory,English input quality could be improved,students'learning interests could be stimulated and English practical teaching could be accelerated respectively.

INVESTIGATION OF TIGHTLY COUPLED SINS/GPS INTEGRATION MIDCOURSE GUIDANCE FOR AIR-TO-AIR MISSILES

The applied problems of SINS/GPS integration navigation system existing in midcourse guidance of air to air missiles have been investigated recently. In comparison with those investigations existing in current publications, a new tightly coupled SINS/GPS integration navigation system for air to air missiles, based on the decorrelated pseudo range approach, is presented in this paper. Because of high jamming and dynamic of air to air missiles, inertial velocity aiding GPS receiver is used to provide a more accurate, jam resistant measurement for midcourse guidance systems. A tracking error estimator is designed to distinguish the correlation that existed between pseudo range measurements and inertial information. It is found better to regard inertial velocity aiding errors as the noise of which statistical properties are unknown. So using mixed Kalman/minimax filtering theory, one can obtain the new tracking error estimator with simple and robust algorithm through constructing a composite filter consisting of two parts: Kalman filter for the noise of known statistics and minimax filter for the unknown. In order to ensure this simple estimator stability, a new method is proposed to choose its parameters, based on Khargonekars work. Moreover, it is demonstrated that the given method also ensures the proposed estimator optimality. All the work mentioned above is involved in the tightly coupled SINS/GPS integration midcourse system design in which a set of low accuracy inertial components is shared by SINS and autopilot. Simulation results of a certain type of air to air missile are presented. Due to decorrelation by the tracking error estimator, only small white noise of pseudo range measurements remains. So it is shown that application of the new midcourse guidance system results in better guidance accuracy, higher jam resistance.

Maneuvering Target Tracking Algorithm Based on Muti-paramter Sequential Extended Kalman Filter

Based on the information theory,the performance of maneuvering target tracking can be improved by increasing the input information( observation vector).In this paper,the estimations of radial acceleration and radial velocity obtained in the signal processing are introduced into the measurement vector by coordinate transformation.In order to solve the problem of high nonlinearity of the radial acceleration,radial velocity and the state vector,a new algorithm of multi-parameter sequential extended Kalman filter( MSEKF) is proposed.The tracking performance of this algorithm is tested and compared with the other tracking algorithms.It is shown that the proposed algorithm outperforms these algorithms in strong and weak maneuvering environments.

Existence of Linear Strategy Equilibrium in Insider Trading with Partial Observations

This paper investigates a linear strategy equilibrium in insider trading in continuous time allowing market makers to know some information on the value of a stock. By the use of filtering theory,the authors prove that in a monopoly market, there exists a unique equilibrium of linear strategy of intensity in a closed form, such that the insider can make positive profits and at which, all of the private information on the value of the stock is released; and the more accurate the information on the value of the stock observed by the market makers, the less the positive profits are made by the insider, and even go to zero. However, there is no Nash equilibrium in a Cournot competition market between two insiders if they both adopt a linear strategy of intensity.

A random finite set based joint probabilistic data association filter with non-homogeneous Markov chain

We demonstrate a heuristic approach for optimizing the posterior density of the data association tracking algorithm via the random finite set(RFS)theory.Specifically,we propose an adjusted version of the joint probabilistic data association(JPDA)filter,known as the nearest-neighbor set JPDA(NNSJPDA).The target labels in all possible data association events are switched using a novel nearest-neighbor method based on the Kullback-Leibler divergence,with the goal of improving the accuracy of the marginalization.Next,the distribution of the target-label vector is considered.The transition matrix of the target-label vector can be obtained after the switching of the posterior density.This transition matrix varies with time,causing the propagation of the distribution of the target-label vector to follow a non-homogeneous Markov chain.We show that the chain is inherently doubly stochastic and deduce corresponding theorems.Through examples and simulations,the effectiveness of NNSJPDA is verified.The results can be easily generalized to other data association approaches under the same RFS framework.

Insider Trading with a Random Deadline under Partial Observations:Maximal Principle Method

For a revised model of Caldentey and Stacchetti(Econometrica,2010)in continuous-time insider trading with a random deadline which allows market makers to observe some information on a risky asset,a closed form of its market equilibrium consisting of optimal insider trading intensity and market liquidity is obtained by maximum principle method.It shows that in the equilibrium,(i)as time goes by,the optimal insider trading intensity is exponentially increasing even up to infinity while both the market liquidity and the residual information are exponentially decreasing even down to zero;(ii)the more accurate information observed by market makers,the stronger optimal insider trading intensity is such that the total expect profit of the insider is decreasing even go to zero while both the market liquidity and the residual information are decreasing;(iii)the longer the mean of random time,the weaker the optimal insider trading intensity is while the more both the residual information and the expected profit are,but there is a threshold of trading time,half of the mean of the random time,such that if and only if after it the market liquidity is increasing with the mean of random time increasing.