离散问题

The rational points of an elliptic curve forms an additive group. The discrete logarithm problem of this group is called elliptic curve discrete logarithm problem.

椭圆曲线上的有理点会形成一个加法群，此加法群上的离散对数问题称为椭圆曲线离散对数问题(elliptic curve discrete logarithm problem)。

The admissible input of 2-D linear discrete singular general model is discussed more deeply, some very effective new criteria for the 2-D singular general model to accept all the input sequence have been developed, and a new algorithm that determines the admissible input sequence of the 2-D singular systems has been proposed.

在线性广义2-D系统可解性方面，首先研究了线性广义2-D连续—离散系统的可解性问题，给出了可解的条件，并给出了等价的判别条件；其次深入研究了线性广义2-D离散系统的允许输入序列问题，给出了系统接受所在区域上的所有输入的新的非常有效的判别方法以及确定系统允许输入序列的新的方法。

It is divided into 3 parts: the 1st part is the description of boundary value which is discreted by using 5 point differential format, the algebraic system is get.

分成3个部分：第1部分是对边值问题的描述，并对边值问题利用5点差分格式进行了离散，得到了其离散代数系统。

The book is divided into 14 chapters, including Introduction, continuous control system theory, process and discrete sampling, Z transform, sampled-data systems, discrete approximation of continuous system the equivalent, based on mathematical transform the classical design method, based on state space pole placement design methodology, multi-variable system of quadratic optimal control, quantitative effects, the choice of sampling period, the digital control system modeling, digital control system for a variety of design methods, variables quadratic optimal control systems, sampling cycle of selection, non-linear control of the problem, as well as digital control system, a typical application - Disk drive servo control design.

全书共分14章，内容包括概论、连续控制系统理论、采样过程和离散化、Z变换、采样数据系统、连续系统的近似离散等效、基于数学变换的经典设计方法、基于状态空间的极点配置设计方法、多变量系统的二次型最优控制、量化效应、采样周期的选择、数字控制系统的建模问题、数字控制系统的各种设计方法、变量系统的二次型最优控制、采样周期的选择、非线性控制的有关问题，以及数字控制系统的一个典型应用——磁盘驱动器的伺服控制设计等。

The application of the lattice Boltzmann method in unsteady open channel flows was studied in detail in the paper. An existing lattice BGK model was mended; For the problem of negative local equilibrium and evolutionary distribution, we proposed a lattice Boltzmann model based on cell-population equilibrium, which is a direct non-negative approximation to the continuous Maxwell distribution. The model reduces the transport and collision, two basic evolution steps in the LB model, to transport of the non-equilibrium distribution.

本文系统的研究了格子Boltzmann 方法在明渠非恒定流中的应用问题，改进了一个现有的LB 模型，数值实验表明此改进是有效的；在平衡态分布函数及分布函数的非负性问题上，作者提出了一个基于单元均衡的格子Boltzmann 模型，通过直接对Maxwell 分布函数的离散化实现对速度分布函数的非负离散，这种方法将传统模型演化过程中的碰撞和输运两个步骤直接表现为粒子的输运。

In this paper, no-wait flow shops scheduling problems for a mixed discrete particle swarm optimization, through the establishment of the location of the vector encoding and scheduling program of mapping relations between the continuous particle swarm optimization algorithm is applied to discrete no-wait flow shops scheduling problem.

针对无等待流水线调度问题提出了一种混合离散化粒子群优化算法。通过建立位置矢量编码与调度方案之间的映射关系将连续的粒子群优化算法应用于离散的无等待流水线工件调度问题。

Due to the discreteness of transformer taps and the switching of shunt capacitance/reactance banks, the rigorous reactive power optimization is the problem of Mixed-Integer Nonlinear Programming involving both discrete and continuous variables.

在电力系统无功优化过程中，由于有载调压变压器分接头的存在和补偿电容／电抗器分组投切的离散特性，使得严格意义上的无功优化问题成为一个离散变量和连续变量共存的混合整数非线性规划(Mixed-Integer Nonlinear Programming，MINLP)问题。

First, the problem of choosing sample time in the discretized variable structure control of continuous-time systems is analyzed, then direct design methods of variable structure for discrete-time systems are discussed.

首先研究了将连续系统的变结构控制理论离散化后应用在离散系统时采样时间选取的问题，接下来讨论了直接针对离散系统的变结构控制的设计。

Most composite schemes switch the compressive scheme and high resolution scheme with a switching function about the slope of the interface in order to overcome the above problem.

为了处里上述的问题，大部分混合离散法都是采用一个与介面斜率相关的转换函数，在高解析离散法和压缩式离散法之间做切换。

This article based on net disperse method has first established the description arbitrary shape non-uniform face target mathematical model.

但是在计算其毁伤效果的时候，难以解决判断网格离散点是否属于目标离散点的问题，没有比较有效的算法对面目标进行离散化。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。