微分算子及梯度算子的逆算子在Hilbert空间的一种展开

微分算子及梯度算子的逆算子作为闭线性算子可以在 Hilbert 空间进行展开,这样就推出了级数的逐项积分公式,而级数收敛是指按 L~2空间的范数收敛。     

一种新的基于统计的词典扩展方法

在建立统计语言模型时,往往会遇到词典的词汇量不够的问题。对于医学等专业领域的语料,这一问题尤为严重。针对这一问题,本文提出了一种新的基于统计的识别新词方法——右边缘扩展法。该方法对分词后的语料中产生的连续单字词进行关联范数估计,利用右边缘扩展的方法判断词的边界。在实验中,我们将右边缘扩展法与基于Witten-Bell back off方法的两两合并法相结合,循环地调整词典,优化语言模型。实验结果表明,该算法具有很高的识别正确率与检出率,可以有效地识别出语料中出现的新词汇,尤其是专业术语。     

大型空间柔性结构基于H2范数的模型降阶

本文给出一种简单易算的大型空间柔性结构的模态缩减法。分析了小阻尼条件下全系统及各阶模态子系统传递函数H2范数的特点，进而定义了系统模态重要度序列，据此序列给出了在H2范数度量下的最优降价系统。仿真算例表明，基于H2范数的模态缩减法明显优于普通的模态截断方法。     

基于边信息的高光谱图像恢复模型

在高光谱图像(HSI)恢复中,如何在模型中有效嵌入先验信息和正确建模噪声一直是研究的两个重点.边信息作为一种基于域的先验知识已经在许多方向取得了成功,然而在高光谱去噪领域仍未受到关注.为了将这种领域知识与高光谱恢复模型自然耦合,提出的方法采用双线性映射的方式将边信息链接到表示观测数据潜在低秩结构的底层矩阵,并使用E-3DTV(enhanced 3-D total variation)正则编码了HSI局部平滑先验.此外该方法使用Lp范数进行噪声建模,进一步增强对腐败的鲁棒性.该方法在两个数据集、七种加噪方式下与五种竞争方法在三个数值指标上进行了比较,结果充分反映了提出方法对复杂噪声场景的有效性和鲁棒性.     

基于压缩感知的高效视频解码算法

无线多媒体传感器网络系统存在无线信道随机衰落以及高误码率等问题,对视频应用的影响尤为突出。压缩感知理论应用于视频信号编码提供了一种抗无线信道随机衰落以及降低误码率的思路,但由于压缩感知重构算法的高复杂度,使得在解码端很难高效实时地恢复出视频序列。本文通过改进SL0算法的迭代搜索方向、迭代搜索方法 以及循环终止条件等提出了一种快速高效的基于平滑范数的压缩感知视频解码算法（Accurate direction smooth l0 algorithm,ADSL0）。算法采用严格的下降方向以及修正的迭代步长,保证了迭代路径的最优。实验结果表明,本文所提算法在重构精度和重构耗时上都明显优于其他同类算法。     

非线性不确定系统的鲁棒镇定与HJI微分不等式

研究一类带模有界条件的非线性不确定系统的鲁棒镇定,定义了Ｌｙａｐｕｎｏｖ意义下的鲁棒镇定概念,得到了系统鲁棒镇定的充分必要条件。结果说明,在带模有界条件下,非线性不确定系统的鲁棒可镇定性与一个扩展的Ｈａｍｉｌｔｏｎ Ｊａｃｏｂｉ－Ｉｓａａｃｓ（ＨＪＩ）微分不等式是否存在正解完全等价。     

Reliable control for a class of uncertain singular systems with interval time‐varying delay

This paper is concerned with the reliable controller design problem for a class of singular systems with interval time‐varying delay and norm‐bounded uncertainties. A more practical model of actuator failures than outages is considered. First, by constructing a novel Lyapunov–Krasovskii functional combined with Finsler's Lemma, an improved delay‐range‐dependent stability criterion for the nominal unforced singular time‐delay system is established in terms of linear matrix inequality (LMI). Then, based on this criterion, an LMI condition for the design of a reliable state feedback controller is presented such that, for all parameter uncertainties and actuator failures, the resultant closed‐loop system is regular, impulse‐free and stable. Numerical examples are proposed to illustrate the effectiveness of the proposed method. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Sugeno测度空间基于复样本的统计学习理论

引入复g_λ随机变量、准范数的定义,给出了复g_λ随机变量的期望和方差的概念及若干性质;证明了基于复g_λ随机变量的马尔可夫不等式、契比雪夫不等式和辛钦大数定律;提出了Sugeno测度空间中复经验风险泛函、复期望风险泛函以及复经验风险最小化原则严格一致性等定义;证明并构建了基于复g_λ随机样本的统计学习理论的关键定理和学习过程一致收敛速度的界,为系统建立基于复g_λ随机样本的统计学习理论奠定了理论基础。     

Concurrent Blind Channel Equalization in Impulsive Noise Environments

In some communication systems the trans- mitted signal is contaminated by impulsive noise with a non-Gaussian distribution. Non-Gaussian noise caused significant performance degradation to communication re- ceivers. The new constant modulus blind equalizer based on Fractional lower-order statistics of the equalizer input, which is defined as FLOS_CMA, is able to mitigate impul- sive channel noise while restoring the constant modulus character of the transmitted communication signal. How- ever, like the Constant modulus algorithm （CMA）, the steady-state Mean square error （]VISE） of the FLOS_CMA algorithm may not be sufficient low for the system to ob- tain adequate performance. This paper proposes a con- current equalizer, in which a Decision-directed least mean p norm （DD_LMP） equalizer operates cooperatively with a FLOS_CMA equalizer, controlled through a non-linear link. Simulation results using M-QAM and 8-PSK signal- ing have shown that besides the capability of compensating the phase offset, the proposed concurrent FLOS_CMA and DD_LMP blind equalizer has faster convergence rate and lower steady-state MSE than the FLOS_CMA approach.     

Automobile-Speed Estimation Using Movie-film Simulation

A silent movie film made by shooting through the windscreen of a car driven at different constant speeds was shown in an auditorium, and subjects asked to estimate the speed of the car. Of the 70 subjects who participated, 35 sat at the front and the remainder at the back.

The speed estimates of those seated at the back were, on average, some 11 per cent higher than those at the front. An explanation for this effect is given. It is shown that those at the correct perspective distance from the screen ( in the present case, those at the front) will receive an impression of speed which most closely resembles the actual speed of the car.

The speed estimates from the front of the auditorium most closely resembled those observed in an earlier field experiment when the subjects' hearing was diminished. It is concluded that the movie technique provides a good simulation of the task in the field experiment if the following two qualifications are made. First, the movie must be viewed from close to the correct perspective distance. Second, a silent movie corresponds to the real situation in which the observer is prevented from hearing.