Based on the optimized three-step search algorithm. Combining threshold judgment as well as local full search, a more efficient motion estimation algorithm is proposed. The algorithm not only inherited the traditional three-step algorithm’s quick speed but also kept the advantages of a relatively small amount of calculation, besides it can avoid the local optimum problem in the three-step search algorithm (TSS). In addition, the algorithm combined with the threshold judgment and local full search algorithm, so it also maintains satisfactory visual quality. Comparing the algorithm with TSS and local full search algorithm (LFS). The algorithm has great performance in search points and peak signal-to-noise ratio. Experimental results show that compared with LFS, search points drop by 34.61% ~ 54.47% .While compared with the TSS, the search points only rise by 6.15% ~ 12.21%. The average PSNR of proposed Algorithm is 0.24dB higher than LFS and 3.30dB higher than TSS.
Stochastic volatility is introduced into the default Heath-Jarrow-Morton framework.Then,using the no-arbitrage condition,the drift restriction condition for the credit spread is derived under the defaulta HJM framework with stochastic volatility introduced above,leading to a credit spread model,which is further transformed into Markovian system under a certain volatility specification.On that basis,empirical research is carried out on the dynamics of credit spread in the default bond market of China.The result shows that there is a significant characteristic of stochastic volatility in the dynamics of short-term credit spread,which is captured by the credit spread model established above.
This paper introduces an estimation approach for the Extended Nelson-Siegel model of termstructure of interest rates based on the genetic algorithm(hereafter GA).Then an empirical comparison ismade between the bootstrap method based on cubic spline interpolation,the Extended Nelson-Siegelmodel based on nonlinear regression and the model introduced in this paper,which shows that the last oneoffers the best performance of the three methods in yield curve fitting and estimation.So yield curves areestimated and analyzed based on the method proposed for the three sample dates and then it is found thatthere are significant differences between yield curves of the initial stage and mid-and late one of the ongo-ing financial crisis in three aspects:the level of the yield curve drops,with different magnitudes for differ-ent parts,while both the slope and curvature increase significantly,which is attributed to the shift of themonetary policy and the recovery of the market confidence in the context of the financial crisis.
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