计数问题

Battista and Clements(1996, 1998) indicate that students are difficult to perspect and imagine the hiding cubes, or coordinate orthogonal views of cubes correctly.

Battista与Clements(1996， 1998)指出学童在解决立方体计数的问题时，无法对隐藏的立方体进行透视与想像，或无法正确协调柱体直角的视点，即使到了国小高年级，仍有一定比例的学生计数错误。

We use different method to study the counting problem of primitive elements in the extension of finite field and obtain a new identity on Euler function.

用不同的方法研究了有限域扩张的本原元的计数问题，并得到一个关于Euler函数的新的恒等式。

We provide a substitution box, exponential permutation which has much measurable security, and give a enumerating result and a fast algorithm of calculating such permutation. An almost perfect nonlinear exponential permutation with high algebric degree is proposed. with some discussion on how to select the parameters of such permutation. The experimental result shows us a conjecture that there exists no such permutation over even dimensional space. As a way of generating substitution boxes, we briefly point out the cryptographic weakness of the exponential functions derived from such permutation. We also present two new cryptographic indexes, fixed point and cyclic structure, on which we investigate the performance of such permutation. Finally, we give a viewpoint about the application of correlation immune functions in designing substitution boxes.

提供了一种可度量安全强度的代换盒－幂置换；详细阐述了幂置换的实现和计数问题；给出了一种计算幂置换的快速算法；从几乎完善非线性幂置换角度讨论了幂置换参数的选取，并提出了一种高次几乎完善非线性置换；通过试验给出了关于偶数维空间上几乎完善非线性幂置换的一个猜想；简要给出了由幂置换派生出的幂函数的密码局限性；针对幂置换，提出了两个密码安全指标：不动点和循环结构；证明了幂置换在这两个指标下的密码性能；简要讨论了相关免疫函数与代换盒设计的关系。

Counting is the combination of mathematics in one of the main content, and generating function is an important tool for counting, therefore, the mother of mathematical functions in the portfolio has an important position is to solve the problem of combination of powerful tools.

计数是组合数学中主要的内容之一，而母函数是计数的重要工具，因此，母函数在组合数学中有着重要的地位，是解决组合问题的强有力的工具。

In this paper we consider the enumeration of subsets of the set, say D, of those Dyck paths of arbitrary length with maximum peak height equal to m and having a strictly increasing sequence of peak height.

本文考虑了由最高峰的高度为m，并且峰的高度沿着Dyck路严格递增的所有Dyck路组成的集合，即集D的子集的计数问题。

In this paper we consider the enumeration of subsets of the set, say Dm, of those Dyck paths of arbitrary length with maximum peak height equal to m and having a strictly increasing sequence of peak height.

孙怡东 ，贾藏芝本文考虑了由最高峰的高度为m，并且峰的高度沿着Dyck路严格递增的所有Dyck路组成的集合，即集合Dm的子集的计数问题。

What is the count to infinity problem?

什么是无限计数问题？

The problem of constructing and enumerating the duadic codes with arbitrary lengths remains open up to now.

Duadic码的构造方法和计数，以及不等价的Duadic码的计数一直是Duadic码研究中的公开问题。

An algorithm of paper counting based on texture analysis is proposed in the paper, in which machine vision method is employed, for the reason that paper counting machines used widely have some defects, such as taking up a lot of room, consuming much energy, being hulking, inconveniencing the maintenance work etc.

针对生产和生活中大量应用的机械纸张计数装置存在体积大、功耗高、笨重和不易保养维护等缺点，提出了一种基于纹理分析的纸张计数算法，试图从机器视觉的角度来解决这一问题。

Employing a general Monte Carlo code MCNP, the following Monte Carlo calculations which are important in the design of PAN shufflers were done:(1) optimization of moderators;(2) detection efficiency variation with the position of a neutron source;(3) multiplication effects and self-shielding effects;(4) isotopic effects;(5) shielding properties of the storage chamber and the assay chamber;(6) the relation between 〓Cf source strength and background neutron count rates.

文章详细讨论了无源方式下中子总计数分析和符合计数分析以及有源方式下缓发中子分析的基本原理，在此基础上，运用通用蒙特卡罗程序MCNP计算了桶装废物分类装置研制过程中所关心的一系列问题：慢化体的优化设计、探测效率随中子源位置的变化情况、增殖和自屏蔽效应、同位素效应、贮存室和测量室对〓Cf源的屏蔽能力、〓Cf源强度与本底计数率的关系，等。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。