系统函数

Properties of efficient portfolios and the efficient frontier to the model are systematically analyzed. Our main results concerning the properties are: every efficient portfolio can be solved by minimizing portfolio risk under a given level of portfolio return or by maximizing portfolio return under a given level of portfolio risk; on the efficient frontier, the risk is a convex and strictly increasing function of the return and the return is a concave and strictly increasing function of the risk; the utility function on the efficient frontier can be expressed as a quasi-concave function of the risk or the return if the investor's utility function is quasi-concave.

从理论上系统地对该模型下的有效投资组合和有效前沿的性质进行了分析，结果表明：每一个有效投资组合可通过在给定期望收益水平的条件下最小化投资组合风险来获得，或者在给定风险水平的条件下最大化期望投资组合收益来获得；在有效前沿上，风险是收益的严格单调递增凸函数，收益是风险的严格单调递增凹函数；当投资者的效用函数是拟凹函数时，则有效前沿上的效用可表达成风险或收益的拟凹函数。

In the first session the fans vibration on-line monitoring system is realized with VC language, also compile auto power spectrum density function, cross power spectrum density function, autocorrelation function and cross correlation function etc spectral analysis function to carry through simple offline fault diagnosis.

首先用稳定性强、扩展性好的VC++语言开发了通风机振动在线监测系统，并编写了自功率谱密度函数、互功率谱密度函数、自相关函数和互相关函数等频谱分析函数来进行简单的离线故障诊断。

Because we mainly involve visual fields of medical science , have placed more contents on the development in the field of medical image of visual technology and argumentation used. Second part It is the visual technology knowledge, the generalization in such respects as the basic principle , basic functions, function store and three-dimensional animation technology to OpenGL ,etc. The realization of the system using OpenGL functions finish that three-dimension demonstration. The third part It is number value that calculate knowledge, three-dimension rebuild technology is it is it is it punish to fit to go on to need, the research of interpolator technology that cant leave, So this part has quoted the Hermite function principle , define cubic Hermite function to begin, calculate the differential coefficient among them draws cubic spline again.

由于我们主要是涉及医学可视化领域，所以将更多的内容放在了可视化技术在医学影像领域的发展与应用的论述；第二部分是可视化技术方面的知识，主要对 OpenGL 的基本原理、基本功能、函数库及三维动画技术等方面的概括，在系统实现时就是通过调用 OpenGL 函数库实现三维显示的；第三部分是数值计算方面的知识，三维重建技术需要进行拟合处理，离不开插值技术的研究，所以这一部分从埃尔米特函数原理开始讨论，引入三次埃尔米特函数，进一步计算时又引用三次样条函数。

In this paper, hyperbolic tangent function method and its some extensions suchas sine-cosine method, extended tanh method, F-expansion method and Jacobi ellip-tic function method are summarized, the idea and technique of hyperbolic functionmethod are explored.

本文对双曲正切函数法及sine - cosine方法，扩展tanh函数法，Jacobi椭圆函数展开法， F-展开法等一些主要的双曲函数方法及其扩展进行了系统的归纳与总结，揭示了双曲函数法的构造思想与技巧。

In this paper the transfer function of noulinear control system is defined over a noncommutative polynomial ring, which can be extended into its quotient ring by Ore Theorem.

本文定义了非线控制系统的传递函数，这种传递函数定义在由一个非交换多项式环扩张而成的商环上用传递函数描述了非线性控制系统的三种基本联接：串联、并联与反馈。

The NEF method is potential in developing new efficient tools for on-line security analysis and control. In study of the method of damping system low-frequency oscillations, this project has proposed the control strategy of oscillation energy function descent.

项目研究中还应用归一化暂态能量函数对电力系统振荡机理进行分析，设计了增加阻尼平抑电力系统振荡的方法，提出了振荡能量函数的概念，得出"振荡能量函数下降法"的控制策略。

Finally the whole system is obtained using a proper nonlinear function based on signum functions.

首先选取合适的不稳定线性系统，利用一系列相互平行的分界面对相空间进行划分，然后通过对该线性系统进行平移变换，使新系统作用于相应的空间区域，最后利用基于符号函数的非线性函数来统一表示整个系统。

Based on the propagation and transformation law of Wigner distribution function through a general axially nonsymmetrical optical system,investigated is the transform relationship of WDF between the input and the output planes of a pair of cylindrical lenses system which is used widely in optical signal processing .

基于维格纳分布函数在一般非轴对称系统的传播和变换规律，讨论了在光学信息处理系统中常用的双柱透镜系统输入和输出面WDF之间的变换关系，在直角坐标中给出了联系该系统相空间坐标的维格纳分布函数的坐标变换关系式和等价的矩阵表示。

After proposing a data model of unordered node labeled tree for XML databases,this paper defines a functional dependency among XML subtrees.In addition,an axiom system to infer functional dependency is given.Moreover,the soundness is proven.

在无序的结点标记树数据模型上定义了XML子树间的函数依赖，并且给出了一套公理系统用来推导函数依赖，以解决函数依赖的蕴涵问题，最后证明了该公理系统是合理的。

The grid multi-scroll chaotic system is constructed by triangular wave series and step function sequence, and the value of the turning point and the balance point in above function are found.

提出了产生 n×m 涡卷混沌吸引子的一种新方法，用三角波函数序列和阶跃函数序列构造网格多涡卷混沌系统，找出函数中平衡点和转折点的值，并对系统的基本动力学特性进行了研究，包括理论分析和计算机模拟仿真。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷