Value Distributions of Exponential Sums From Perfect Nonlinear Functions and Their Applications

In this paper we present a unified way to determine the values and their multiplicities of the exponential sums Sigma_xisinF(q)zeta_p ^Tr(af(x)+bx)(a,bisinF_q,q=p^m,pges3) for all perfect nonlinear functions f which is a Dembowski-Ostrom polynomial or p = 3,f=^x(3(k)+1)/2 where k is odd and (k,m)=1. As applications, we determine (1) the correlation distribution of the m-sequence {a_lambda=Tr(gamma^lambda)}(lambda=0,1,...) and the sequence {b_lambda=Tr(f(gamma^lambda))}(lambda=0,1,...) over F_p where gamma is a primitive element of F_q and (2) the weight distributions of the linear codes over F_p defined by f.     

关于完全非线性函数的非线性度的界

非线性函数在编码和密码领域中扮演着非常重要的角色,衡量函数的非线性性质很重要。非线性度和差分概率是衡量函数非线性性质的重要指标,差分概率均匀的函数称为具有完全非线性的函数。文中改进了Carlet和Ding所给出的完全非线性函数的非线性度的上界和下界,提出了更好的界的优化问题模型。     

Higher Order Nested Wigner Distributions: Properties and Applications

The concept of Wigner distribution (WD) is extended to higher-order nested Wigner distributions. The nested ambiguity function (NAF) is also derived naturally by employing the known interrelation between the WD and the ambiguity function (AF). These distributions are obtained by nesting a function within itself a number of times. The definitions of these new multidimensional distributions are given in analogy to the standard first-order 2-D distributions in both temporal/spatial and spectral forms and follow the definitions of quartic distributions presented in and . Some important properties are derived and discussed, including interrelationships between the various representations, marginals, correlations, and uncertainties, as well as their geometrical characteristics. The second-order nested Wigner distribution (NWD) is used to showcase the power of such distributions in potential application areas, such as signal estimation, signal separation, and radar signal analysis. For such signal processing tasks, it is demonstrated that the NWDs can be successful in situations where the standard 2-D distributions have proved to be inadequate     

On Almost Perfect Nonlinear Functions Over$mmb F_2^n$

We investigate some open problems on almost perfect nonlinear (APN) functions over a finite field of characteristic 2. We provide new characterizations of APN functions and of APN permutations by means of their component functions. We generalize some results of Nyberg (1994) and strengthen a conjecture on the upper bound of nonlinearity of APN functions. We also focus on the case of quadratic functions. We contribute to the current works on APN quadratic functions by proving that a large class of quadratic functions cannot be APN     

一类布尔函数的性质及其应用

讨论了不重复齐次k次布尔函数的密码性质,给出了这类函数所满足非线性准则;研究了这类函数在非线性组合函数的构造中的应用,得到了几个基于这类函的构造定理。     

几种新型非线性光学晶体的性能和应用

本文介绍LBO、BBO、KTP、LAP晶体的物理、化学、机械和抗潮等方面的性质,给出了它们折射率的Sellmeier方程、非线性光学系数、几种常见波长的位相匹配的计算及测量结果。并对它们的性能进行了比较和讨论。还介绍了用这些晶体制成的非线性光学器件的性能和指标,最后介绍了LBO、BBO、KTP晶体在光学参量振荡和在“飞秒’脉宽激光测量上的应用。     

Characterization of Linear and Nonlinear Properties of GaAs MESFET's for Broad-Band Control Applications

GaAs MESFET's designed for control applications have improved switching performance compared to FET's designed for low-noise or high-power amplifiers. A broad-band switching cutoff frequency figure of merit close to 500 GHz has been achieved with both epitaxial and ion-implanted devices having n/sup +/ surface layers and/or channel dopings above 2.0 X 10/sup 17/ cm/sup -3/. Power handling nnder CW conditions is limited in the nonconducting state (FET dc biased into pinchoff) by the difference between the gate breakdown voltage and the pinchoff voltage, while conducting-state power handling is limited by the open-channel current-handling capability. For optimum switching frequency figure of merit, individual gate finger widths greater than those used in amplifier devices for the same maximum frequency of operation are necessary. The large (~5 k Omega) resistor in series with the gate has important ramifications in optimizing the power-handling capability for broad-band applications.     

Life Distributions Derived from Stochastic Hazard Functions

Most of the familiar time-to-failure distributions used today are derived from hazard functions whose parameters are assumed constant. An unconditional time-to-failure distribution is derived here by assuming that a parameter of a classical failure distribution (viz., exponential and Weibull) is a random variable with a known distribution. With the use of the derived compound distributions and Bayesian techniques, it is possible to join the test data with prior information to arrive at a combined, and possibly superior, estimate of reliability. The prior distributions considered here are the two-point, the uniform, and the gamma. Conceptually, such a scheme may be a more realistic model for describing failure patterns under specific conditions.     

具有均匀差分分布的一类置换

本文研究了置换的差分分布，证明了如果一个置换的坐标函数的每个线性组合都有非零线性结构，则该置换具有均匀差分分布的充要条件，是它的坐标函数的每个非零线性组合都是只有一个恒变线性结构的部分ｂｅｎｔ函数，并且它的坐标函数的不同非零线性组合所具有的非零线性结构互不相同。还证明了如果一个偶数维置换的坐标函数的每个线性组合都有非零线性结构，则该置换一定不具有均匀差分分布。本文还研究了Ｋ．Ｎｙｂｅｒｇ构造的能够达到最大非线性度的置换，证明了这些置换都具有均匀差分分布，从而解决了具有均匀差分分布的置换的存在性问题。     

Programmable Hash Functions and Their Applications

We introduce a new combinatorial primitive called programmable hash functions (PHFs). PHFs can be used to program the output of a hash function such that it contains solved or unsolved discrete logarithm instances with a certain probability. This is a technique originally used for security proofs in the random oracle model. We give a variety of standard model realizations of PHFs (with different parameters).     

A New Family of Ternary Almost Perfect Nonlinear Mappings

A mapping f(x) from GF(pⁿ) to GF(pⁿ) is differentially k-uniform if k is the maximum number of solutions x isin GF(pⁿ) of f(x+a) - f(x) = b, where a, b isin GF(pⁿ) and a ne 0. A 2-uniform mapping is called almost perfect nonlinear (APN). This correspondence describes new families of ternary APN mappings over GF(3ⁿ), n>3 odd, of the form f(x) = ux^d + x^{d 2} where d₁ = (3^n-1)/2 - 1 and d₂ = 3ⁿ - 2.     

Characterization and Properties of Bent-Negabent Functions

A further characterization of the bentnegabent functions is presented. Based on the concept of complete mapping polynomial, we provide a necessary and sufficient condition for a class of quadratic Boolean functions to be bent-negabent. A new characterization of negabent functions can be described by using the parity of Hamming weight. We further generalize the classical convolution theorem and give the nega-Hadamard transform of the composition of a Boolean function and a vectorial Boolean funct...     

The Structure of General Interference Functions and Applications

This paper provides a theoretical framework for the analysis of interference-coupled multiuser systems. The fundamental behavior of such a system is modeled by interference functions, defined by axioms “nonnegativity, ”scale-invariance,” and “monotonicity.” It is shown that every interference function has an interpretation as the optimum of a min-max problem, where the optimization is over a closed comprehensive positive coefficient set. This provides new insight into the structure of general interference functions and its elementary building blocks. Conversely, it is shown that every closed comprehensive positive set can be expressed as a level set of an interference function. This shows a close connection between the analysis of interference functions and multiuser performance regions, which are typically closed comprehensive. The generality of this framework allows for a wide range of potential applications. As an example, we analyze the problem of interference balancing.      

红外光纤及其应用

介绍了适宜于制备红外光纤的材料及红外光纤制备工艺，综述了红外光纤在军事、光谱学、热成像、测温、红外通讯、激光能量传输等领域的应用。如果能继续降低红外光纤的传输损耗，增大优质光纤维长度，制备出适用的低噪声探测器，那么，红外光纤在上述领域的应用价值将更大，也将会开拓出更广阔的应用领域。     

Piecewise Nonlinear Approach to the Implementation of Nonlinear Current Transfer Functions

A piecewise nonlinear approach to the nonlinear circuit design has been proposed in this paper. It is to approximate a target nonlinear transfer function by a particular combination of selected nonlinear pieces. The pieces can be produced by one or more analog blocks involving nonlinear devices. This approach can be applied to design nonlinear circuits to implement various current transfer functions. By controlling the operation modes of the transistor pair in a simple current mirror, one can modulate the current transfer function in a radical or fine-tuning manner. It is thus possible for the same current mirror to generate very different nonlinear pieces in different sections of its input range. In order that the control is done automatically by the input current, or in other words, the operation of the transistors is made to be input-current-dependent in a controlled manner, a series structure of two transistors has been proposed to be incorporated in the current mirror. The dependency can be made different by placing the structure in different places of the current mirror and/or by making the two transistors complementary or not, which makes the variations of the nonlinear function. Several current mirrors have been designed. Each of them consists of a very small number of transistors and performs a defined nonlinear current transfer function. The circuits have been simulated with HSPICE to validate the functions. The successful results have been obtained and are presented in the paper.     

CMOS与CCD性能及高清应用比较

互补金属氧化物半导体（CMOS）与电荷耦合器件（CCD）是目前主流的图像传感器件。CMOS与CCD图像传感器的研究几乎同时起步,但是CMOS的应用有相当一段时期落后于CCD。近些年,各个级别质量的图像采集领域,都有COMS图像传感器的应用。从CMOS和CCD图像传感器采用的技术手段和性能表现两大方面做了较为全面的比较和分析,给出了较为详细的对比参数表,并介绍了CMOS和CCD传感器在高清摄像方面的高端应用。     

Best Estimates of Functions of the Parameters of the Gaussian and Gamma Distributions

General formulae for minimum variance unbiased estimators of a broad class of functions of the parameters of the Gaussian and gamma distributions are given. The formulae are easy to employ and are applied here to several examples familiar to the reliability engineer.     

二阶锁相环非线性捕获和非线性跟踪性能研究

采用MATLAB软件,编制了求解描述二阶PLL非线性捕获的二阶非线性微分方程的程序,计算机自动绘制了相轨迹和时间响应图;求出了二阶PLL的捕获带随初始相差的变化关系曲线.