查询词典 summation formula

This passage analyzes the advantage and disadvantage of the Boolean Model and the Vector Space Model in information retrieval model: the Boolean Model is simple to realize, but its classification ability is limited and the logic expression formula is strict.

本文分析了信息检索中传统文档特征表示的布尔逻辑模型和向量空间模型的优缺点：布尔逻辑模型虽机制简单、容易实现，但是它的分类能力有限且逻辑表达式过于严格；向量空间模型将文档映射到连续域向量空间，为进一步的权重计算等多元处理提供了基础，但容易忽略文档集合中各个文档的一些共有特征。

In the fourth chapter, firstly it introduces the Boolean functions algebraic expressions of the 2-value clock-controlled stop-and-go generator and Gunther generator. It reveals the balanced property of the two kinds of Boolean functions, and studies the Walsh cycle spectrum and the autocorrelation function. It also obtains the coincidence rate of their output sequences with affine sum of some bits of input sequences, and analyzes their ability of resisting the best affine approximation cryptanalysis and differential cryptanalysis. Secondly, we properly present a new definition of the Best Affine Approximation, namely BAA on the Boolean vector functions, followed by the spectral characteristic of such defined BAA attacks through using the decomposition formula of the union distribution for random variables. A lower bound of such BAA attacks is proposed. Finally, we also study the spectral characteristic of the second kind of nonlinearity of Boolean vector functions, followed by a higher bound of such nonlinearity. Furthermore, the limited relationship between the second kind of nonlinearity of Boolean vector functions and the linear structure of the linear combination of every component is analyzed.

在第四章中，首先给出了2值密钥流"停走生成器"和"衮特生成器"中实际存在的布尔函数的代数表示，揭示了这两类布尔函数的平衡性，随后研究了它们的Walsh循环谱和自相关函数等，得到了它们的输出序列与输入序列中的某些bit的仿射项的符合率，分析了它们抵抗最佳仿射逼近攻击和差分攻击的能力；其次，我们合理地给出了布尔向量函数最佳仿射逼近的新定义，利用布尔随机变量联合分布的分解式考察了相应的谱特征，并给出了布尔向量函数与其最佳仿射逼近的符合率的一个下界；最后，我们还考察了布尔向量函数第二类非线性度的谱特征，给出了布尔向量函数第二类非线性度的一个上界，并揭示了布尔向量函数第二类非线性度与其各个分量的线性和的线性结构之间存在的制约关系。

Using the theories of probability, algebra and spectral theory comprehensively, we investigate some related characteristics of logic functions in cryptography: Firstly, we introduce m order generalized s - correlation immunity of Boolean vector functions and prove that the higher order generalized ε- correlation immunity can guarantee the lower order generalized ε- correlation immunity. Then by applying decomposition formula of joint distribution of Boolean random vectors, we give a spectrum criterion of m order generalized e - correlation immunity of Boolean vector functions. Furthermore, we show that the algebraic degree of m order generalized e - correlation immune Boolean vector functions is not restricted by the correlation immune orders.

本文主要运用概率论的思想和方法，并结合代数学和频谱理论的相关知识，对密码学中逻辑函数的有关性质进行了研究，主要包括以下三个方面的内容：首先，对布尔向量函数的相关免疫性进行了拓展，给出了k维布尔向量函数m阶广义ε-相关免疫的概念，证明了布尔向量函数的高阶广义ε-相关免疫性蕴含低阶广义ε-相关免疫性，并根据布尔随机向量联合分布分解式得到了布尔向量函数m阶广义ε-相关免疫的一个谱判别条件，还说明了m阶广义ε-相关免疫布尔向量函数的代数次数不受相关免疫阶数的制约。

Recent measurements on CO2-laser-assisted electron-atom collisions have shown large inconsistencies with the Kroll-Watson formula.We use Born approximation theory to carry out a detailed study of the problem.

最近的CO2激光辅助电子-原子碰撞的测量结果与K-W公式存在着非常大的差异，用玻恩近似理论对此进行了详细的研究。

The calculations have shown that the second Born approximation can give better results,as compared with experiments.The prediction of K-W formula is only equivalent to the first Born approximation.

结果表明第二玻恩近似结果与实验结果符合得比较好，K-W公式的预言只相当于第一玻恩近似。

Three kinds of mass attenuation coefficient have been used, which are the monoenergetic MAC at the mean energy of the MC simulated spectrum, the effective MAC of the Born approximation formula spectrum and the effective MAC of the MC simulated spectrum.

在密度提取中使用了3种不同的吸收系数－MC谱光子平均能量对应的单能质量吸收系数、波恩近似公式谱有效质量吸收系数和MC谱有效质量吸收系数。

But the effect of boron in the formula for calculation of the electron va...

而在以往的计算电子空位数的公式中，硼的影响一直没有被考虑进去。

My sincere thanks to Bort from EU-Ravencrest who figured out this formula for me!

在此我真诚的感谢来自欧服Ravencrest服务器的Bort帮我计算出这个公式！

Consequently, we get an estimate formula of the number n_1, bounded above by a polynomial of degree 24 in the parameters of F.

从而给出n_1的一个以F的参数的24次方为上界的估计式。

Then we get an estimate formula of the number i\;bounded above by a polynomial of degree 9 in the parameters of F. As pointed by D.

从而给出n_1的一个以F的参数的9次方为上界的估计式。D。

Researches reveal that students who suffer from corporal punishment tend to resort to violence in their future life.

研究表明遭受过肉体惩罚的孩子倾向于在他们今后的人生中使用暴力。

Total sugar of sarcocarp and chlorophyll of pericarp increased firstly, and then decreased afterward along with altitude; Titratable acidity, ascorbicacid and anthocyanin of pericarp were increased along with altitude; The content of protein increased firstly and decreased afterward along with altitude; Carotenoid of pericarp were decreased along with altitude.

果肉总糖和果皮叶绿素含量随海拔高度升高先升高后降低；可滴定酸、维生素C和果皮花青苷含量均随海拔升高而升高；蛋白质在1720m处最大，1420m处最小；果皮类胡萝卜素随海拔升高而降低。