一类积分不等式的机器判定

将一类积分不等式转化为Tarski模型外的齐次对称多项式不等式,该类齐次对称多项式的次数是给定的,变元个数可以是任意多个,并且多项式的系数是与变元个数相关的变系数.这些特点与杨路等人最近提出的几个公开问题密切相关,是比较有代表性的一类齐次对称多项式.然后利用Timofte关于对称多项式不等式判定的降维方法,结合不等式证明软件BOTTEMA及差分代换方法,给出对应的一类Tarski模型外的齐次对称多项式不等式的机器判定算法,从而实现原积分不等式的机器判定.当给定的积分不等式及齐次对称多项式不等式不成立时,可给出具体不成立的数值反例.应用例子表明问题的广泛性及算法的有效性.     

Numerical solution of Riccati equation using the cubic B-spline scaling functions and Chebyshev cardinal functions

Two numerical techniques are presented for solving the solution of Riccati differential equation. These methods use the cubic B-spline scaling functions and Chebyshev cardinal functions. The methods consist of expanding the required approximate solution as the elements of cubic B-spline scaling function or Chebyshev cardinal functions. Using the operational matrix of derivative, we reduce the problem to a set of algebraic equations. Some numerical examples are included to demonstrate the validity and applicability of the new techniques. The methods are easy to implement and produce very accurate results.     

半导体照明中结温的电学法测试与优化

基于电学法测试半导体照明的结温,实现了结温测试的电路,采用脉冲调制对LED的瞬态结温值进行测试.实脸发现,结温与正向电压的标定系数K值是影响结温测试精度的主要因素,分析了产生误差的主要原因,并对该系数进行修正.测试结果表明:结温的实测值与参考值有良好的一致性,存在误差的原因是采样的延时时间较长,可提高数据采样率和剔除不...     

Adaptive predistortion using threshold decomposition‐based piecewise linear modeling

A new adaptive predistortion approach for nonlinear power amplifiers based on the piecewise linear (PWL) approximation of nonlinear functions is presented. The PWL model is obtained using threshold decomposition (TD) of the input‐output characteristics. The TD based PWL model is used to develop a baseband predistorter using both the direct and the indirect learning architectures. The proposed predistorter is proved to provide a better performance in suppressing nonlinear distortion than conventional polynomial predistorters and a reduced hardware complexity as compared to lookup table (LUT) approach. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Efficient bit-parallel multipliers over finite fields GF(2)

Hardware implementation of multiplication in finite field GF(2^m) based on sparse polynomials is found to be advantageous in terms of space-complexity as well as the time-complexity. In this paper, we present a new permutation method to construct the irreducible like-trinomials of the form (x + 1)^m + (x + 1)ⁿ + 1 for the implementation of efficient bit-parallel multipliers. For implementing the multiplications based on such polynomials, we have defined a like-polynomial basis (LPB) as an alternative to the original polynomial basis of GF(2^m). We have shown further that the modular arithmetic for the binary field based on like-trinomials is equivalent to the arithmetic for the field based on trinomials. In order to design multipliers for composite fields, we have found another permutation polynomial to convert irreducible polynomials into like-trinomials of the forms (x² + x + 1)^m + (x² + x + 1)ⁿ + 1, (x² + x)^m + (x² + x)ⁿ + 1 and (x⁴ + x + 1)^m + (x⁴ + x + 1)ⁿ + 1. The proposed bit-parallel multiplier over GF(2^4m) is found to offer a saving of about 33% multiplications and 42.8% additions over the corresponding existing architectures.     

基于混沌扩频和能量系数差的音频盲水印算法

提出一种基于混沌扩频和能量系数差的小波域数字音频盲水印算法。采用混沌扩频序列对原始水印进行加密,小波算法对原始音频信号进行分解,引入心理声学模型选取适当的阈值,根据高频系数分量和低频系数分量的能量差值与阈值的大小关系,实现对水印信息的嵌入、提取和盲检测。在提取过程中结合线性伸缩恢复的方法消除时间轴上线性伸缩带来的影响。实验结果表明,该算法对多种音频文件的操作和攻击均具有良好的鲁棒性。     

无线传感器网络动态密钥管理方法

设计安全、合理的密钥管理方法,是解决无线传感器网络安全性问题的核心内容.提出了EEHS(a novel energy efficient and highly survivable dynamic key management scheme),是一种基于EBS(exclusion basis system)的、适合于大规模分簇式无线传感器网络的动态密钥管理方法,它具有安全性强、能量效率高、动态性能好、可扩展性强等特点.一种新型多项式密钥(同化多项式密钥)被运用在了EEHS的EBS管理密钥中,显著地提高了网络的抗捕获能力.当节点被捕获时,EEHS还可以动态取消并更新被捕获节点所拥有的全部密钥,最终驱逐被捕获的节点.为提高网络的能量效率和鲁棒性,EEHS将密钥分配和密钥生成等功能分配给簇内不同的功能节点,且传感器节点轮流作为功能节点使用.仿真与分析结果表明,与相关工作相比,EEHS可以显著提高网络的能量效率、延长网络寿命、加强网络安全性.     

基于改进齐次多项式技术的离散时间2-D T-S模糊系统的收敛镇定条件

通过利用改进的齐次多项式技术来研究了Roesser型二维T-S模糊系统的镇定设计问题. 首先, 提出了一种用来镇定该二维T-S模糊系统的一种新型非二次控制率, 并且通过应用两种改进的齐次多项式技术得到了保守性更小的镇定条件. 随着所选用的齐次多项式参数依赖矩阵度数的增加, 所得结果的保守性会越来越小. 其次, 为了继续减少保守性, 提出了一种新的右侧松弛变量引入方法, 该方法适合于齐次多项式情形. 最后, 仿真实验验证了所提方法的有效性.     

Polynomial based scheme (PBS) for establishing Authentic Associations in Wireless Mesh Networks

The varying degree of mobility of Mesh Clients has provided much more flexibility in Wireless Mesh Networks, and establishing an Authentic Association among entities is a non-trivial problem. In this paper, we introduce a Polynomial Based scheme which provides pair-wise connectivity, low communication, marginal storage overhead and high scalability while making on the fly Authentic Association feasible. The proposed scheme is also observed to be resilient against both traffic analysis and node capture attacks.