近似度

The fluctuation of available wireless link bandwidth motivates the study of adaptive multimedia services in wireless/mobile networks This paper focusses on a bandwidth adaptation scheme, which takes the maximum revenue as the objective The optimal bandwidth adaptation algorithm which seeks to achieve maximum revenue is an NP hard problem, because it has to investigate every adaptation case A bandwidth adaptation scheme based on genetic algorithm is proposed, which achieves near optimal total revenue with much less complexity compared to an optimal bandwidth adaptation algorithm Simulation is carried out to compare the algorithm with an optimal bandwidth adaptation algorithm, the results reveal that the genetic algorithm approximates the optimal solution very well

无线链路带宽的快速波动推动了无线/移动网络中对适应的多媒体服务的研究以无线网络系统的利润最大化为目标，研究适应的多媒体应用的带宽适应方案达到利润最大化的最优带宽适应算法是一个NP hard问题提出一个基于遗传算法的带宽适应方案，在算法复杂度大大低于最优算法的同时，获得的利润值近似最优性能分析和实验结果证明了这一结论1 引言因特网和无线/移动通信技术的迅速发展，推动了两者服务的融合无线/移动环境下因特网服务的提供需要解决的一个关键问题是QoS保证提供QoS保证的一个重要技术手段是连接接纳控制 [1] CAC算法的目标是在保证切换连接请求丢弃率满足系

The Estimation Model works well in finding out significant criteria and predicating next year's ranks.

我们以2001到2003年的资料实验，并以该实验结果预测2004年的国家排名，结果与IMD 2004所公布之排名相当近似，证实此一模式具高可靠度。

To improve the magnetic field homogeneity, therefore, a cylinder magnet from several crescent-shaped magnets is presented.

为此，采用一种具有磁化方向近似线性分布的离散新月形磁块构成圆柱形磁体以改善二极磁场的均匀度。

The finite difference time-domain method is stable and easy to be used, but due to the fact that it approximates the space derivatives in Maxwells curlequations by central difference, FDTD usually requires more than 20 grids perwavelength to achieve acceptable accuracy. As a contrast, pseudospectraltime-domain method approximates the space derivatives by pseudospectralmethod, which guarantees the accuracy, theoretically requiting only 2 grids perwavelength.

传统的电磁场数值算法——时域有限差分法稳定而易于实现，但由于FDTD采用中心差分近似Maxwell旋度方程的微分，每个波长上需要取的网格数通常较多，而时域伪谱法采用伪谱法求微分，理论上每个波长只需要取两个网格便可以达到较高的精度。

Weak electrolyte ionization degrees can be approximately obtained by the conductivity ratio, namely:α= ma0, mam, and 0, m respectively, the molar electrolyte conductivity and limiting molar conductance (ie, fully ionized after a solution of the conductivity).

弱电解质的电离度可近似地由电导比求得，即：α＝ma0，mam和0，m分别为电解质的摩尔电导和极限摩尔电导（即完全 a电离后溶液的电导）。

From the kinetic differential equations of the photon in the equatorial plane of the spherical symmetrical gravity field, the post-post-Newtonian amendments for radar echo delay test in the Reissner-Nordstrm field are discussed using the post-Newtonian approximation method.

从球对称引力场中光子在赤道面上的运动微分方程出发，采用后牛顿近似方法，讨论了Reissner-Nordstrm度规场中雷达回波延迟实验的后后牛顿修正。

Characteristics and principles of time clustering and frequency with a seismic sequence of more 380 years (1615 —1998) are performed using fractal theory and rescaling range analysis theory. It is concluded that the fiactal dimensions of seismic subset are similar to each other, the mean value is about 0.405, and interval of scale invariance can change 1-2 magnitude order. It is also found that the Hurst index ranges from 0.5412 to 0.5580. The results show that there is of statistical self-similar among different magnitude earthquakes in the area of bridge site.

应用分形理论和R/S分析原理，编写了程序，分析和研究了桥址区的380多年（1615～1998）地震序列的地震时间从集和地震频度特征及规律，得出桥址区不同震级范围的子集合具有近似相等的分维值，约为0.405，子集合无标度区可跨1～2数量级；不同震级层次的地震频度Hurst指数为0.5412～0.5580，都表明了桥址区不同震级层次的地震之间具有统计自相似性。

The same viscosity, pressure, shaft power and speed linearly proportional to.

同一粘度、压力下，轴功率与转速近似成正比。

Same speed, viscosity, the shaft power and pressure approximation is proportional to.

相同转速、粘度下，轴功率与压力近似成正比。

The same viscosity, pressure, pump flow and speed linearly proportional to.

相同粘度、压力下，泵的流量与转速近似成正比。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。