含参数一元二次不等式模型分类解法

含参数不等式的求解问题一直是高中数学的一个难点,求解这类问题,需要学生具有一定的分析能力和掌握相应的解题技巧.本文先介绍含有一个参数不等式求解的几个基本模型,然后介绍含有多个参数一元二次不等式的求解模型.     

Origin 6.O软件在求解化学模型参数中的应用

介绍了数学工具软件Origin6.0在化学模型参数求解中的线性拟合和非线性拟合的典型应用。Origin6.0改变了传统的求解模型参数的方法,提供了对数列直接进行函数拟合的方法,可以方便、迅速地求解出相当复杂的模型参数,并能同时得到建立模型的相关性检验数据。     

FDM表面粗糙度偏最小二乘回归建模研究

产品的表面质量差严重制约了熔融沉积成型(fused deposition modeling,FDM)工艺的发展,通过粗糙度成型机理构建参数模型是提升FDM 成型件表面质量的重要途径。文章以某FDM 打印设备成型件的水平表面粗糙度为例,通过探讨参数三次曲线与多段直线拟合的丝宽模型,利用粗糙度的几何机理提出了基于3 个主要工艺参数的回归模型,采用样条变换的非线性偏最小二乘回归(partial least squares,PLSR)建立对所选参数的有效预测模型,并对建模中未覆盖的不同打印参数下的实验数据样本进行校验,分析工艺参数对水平表面粗糙度的影响。通过以上研究方法,提高了水平表面粗糙度预测效率,获取了相关的经验知识。     

模型数据的拟合

本文介绍了如何应用Matlab软件来拟合模型中的参数，以及把非线性模型转化成线性模型的技术。     

Origin6．0软件在求解化学模型参数中的应用

介绍了数学工具软件Origin6．0在化学模型参数求解中的线性拟合和非线性拟合的典型应用。Origin6.0改变了传统的求解模型参数的方法，提供了对数列直接进行函数拟合的方法，可以方便、迅速地求解出相当复杂的模型参数，并能同时得到建立模型的相关性检验数据。     

三次参数曲线拟合算法的优化研究

计算机图形学的许多著都曾对三次参数曲线的参数拟合算法了一些讨论，但在曲线方程确字下来后，如何进行快速的似合，尚未有一个统一的优化算法，本文通过分析研究，给出了一种可适用于任意三次曲线段拟合的优化算法，较大地提高了计算效率。     

基于倒数累加的非等距灰色模型及其应用

在对原始数据序列的一次累加生成中,考虑到序列的间距和原始数据序列的单调性因素,给出了对非等间距递减序列建立GM(1,1)模型的又一种新的方法——倒数累加生成.实例表明文中提出的方法概念明确、计算方便、有较高的拟合和预测精度.     

电力二次设备继电保护系统失效模型研究

继电保护设备是一种重要的电力二次设备,继电保护装置分为继电保护装置本体和二次回路．文章通过对继电保护装置本体应用软／硬件失效模型进行风险评估,对二次回路应用故障树模型进行分析,建立了继电保护系统失效模型,该模型能够帮助电力自动化系统较准确地判断出系统的故障率和运行可靠性．     

最小二乘配置的几何算法

将H空间理论应用于广义最小二乘原理的几何解释，对最小二乘配置模型等价转换，利用几何解释分别推导该模型中的倾向参数、滤波参数以及推估参数。结果表明几何算法同时兼顾形象性与简洁性，同参数的代数算法保持一致。     

发电机参数聚合及其动态仿真

同调发电机聚合参数的优化对等值后系统的动态特性有重要影响.目前频域拟合法是发电机参数聚合常用的方法,该方法是通过目标函数确定出等值发电机的多个参数,这些参数的准确性直接关系到等值的效果.对于目标函数中多个变量的寻优,为了避免局部寻优的结果,可以考虑将改进蚁群算法的模型应用于基于频域拟合的发电机动态参数聚合中.通过新英格兰39节点系统实际算例优化结果和动态仿真结果比较分析,验证了该方法在发电机参数聚合中的有效性.     

几种大气折射性湍流结构参数C~2_n模型比较

本文通过比较几种大气折射性湍流结构参数C_n~2模型,提出一种较为切合实际模型。     

工程测量软件包设计——线路曲线测设工具

本文利用VB面向对象化的程序设计方法特点,结合工程测量中曲线测设中的具体要求及放样方法,编写了几个求解曲线放样参数的小程序.简化了繁锁的计算,并实现了放样参数的文本保存、编辑和打印等管理.     

Observed Score Linear Equating with Covariates

This paper examined observed score linear equating in two different data collection designs, the equivalent groups design and the nonequivalent groups design, when information from covariates (i.e., background variables correlated with the test scores) was included. The main purpose of the study was to examine the effect (i.e., bias, variance, and mean squared error) on the estimators of including this additional information. A model for observed score linear equating with covariates first was suggested. As a second step, the model was used in a simulation study to show that the use of covariates such as gender and education can increase the accuracy of an equating by reducing the mean squared error of the estimators. Finally, data from two administrations of the Swedish Scholastic Assessment Test were used to illustrate the use of the model.     

Error analysis of stereo SAR geolocation model for spaceborne SAR

Stereo synthetic aperture radar (SAR) geolocation model is an important geolocation model for spaceborne SAR. However, the error of stereo SAR geolocation model has not been analyzed in detail. This paper deduced the geolocation error formulas of the stereo SAR geolocation model and then compared the geolocation error with range Doppler (RD) geolocation model. Through computer simulation, we could get the advantages and disadvantages of the stereo SAR geolocation model.     

3-D Fracture Network Modelling in Hydropower Engineering Based on Optimal Monte Carlo Simulation

Effectively and accurately modelling the spatial relation of fracture surfaces is crucial in the design and construction of large hydropower dams having a complex underlying geology. However, fracture surfaces are randomly formed and vary greatly with respect to their spatial distribution, which makes the construction of accurate 3-D models challenging. In this study, we use an optimal Monte Carlo simulation and dynamic conditioning to construct a fracture network model. We found the optimal Monte Carlo simulation to effectively reduce the error associated with the Monte Carlo method and use dynamic conditioning to ensure the consistency of the model with the actual distribution of fractures on the excavation faces and outcrops. We applied this novel approach to a hydropower station on the Jinshajiang River, China. The simulation results matched the real sampled values well, confirming that the model is capable of effectively and accurately simulating the spatial relations in a fracture network.     

一种改进的FFT离散频谱相位差加权校正算法

为解决用传统相位差法进行频谱校正精度不高的问题,提出了一种改进的FFT离散频谱相位差加权校正算法。该算法是通过将相位差中最大值校正误差与次大值校正误差按一定比例进行加权来获得频谱校正结果。对此的仿真结果表明,该算法与传统相位差法相比,在频谱最大值相同的情况下,频率校正误差的频率分辨率提高了近90%,提高了频率校正精度。     

An error resilient scheme for H.264 video coding based on distortion estimated mode decision and nearest neighbor error concealment

Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resilient coding scheme for H.264 and uses techniques of mode decision, data hiding, and error concealment to reduce the damage from error propagation. This paper proposes a system with two error resilience techniques that can improve the robustness of H.264 in noisy channels. The first technique is Nearest Neighbor motion compensated Error Concealment (NNEC) that chooses the nearest neighbors in the reference frames for error concealment. The second technique is Distortion Estimated Mode Decision (DEMD) that selects an optimal mode based on stochastically distorted frames. Observed simulation results showed that the rate-distortion performances of the proposed algorithms are better than those of the compared algorithms.     

Finite time-horizon Markov model for IEEE 802.11e

We model wireless local area network channel utilization over a finite interval through a finite time-horizon Markov （FTHM） model. By accurately capturing time-varying utilization, the FTHM model allows for generally distributed transmission-opportunity （TXOP） duration, which most existing models do not account for. An absorbing state is introduced to limit the lifetime of the counting process, resulting in a non-ergodic Markov chain that is solved via transient analysis. The model predictions for time-varying utilization are validated by simulation with errors of no more than 0.1% after eight beacon intervals. Moreover, we show that the FTHM model prediction error is below 4% for Poisson distributed and uniformly distributed TXOP durations.     

基于模糊控制的DC-DC开关电源的研究

与经典的PID控制器不同,模糊控制不需要获取系统精确的数学模型．根据系统的要求,设计模糊控制器,以给定参考电压与实际电压之间的偏差及其微分作为输入,通过合理的推理规则,得到占空比输出,去控制开关管的开关时间．论述了模糊控制器的详细设计过程,以及在MATLAB中建立仿真模型的过程．仿真结果表明系统具有较好的稳态和动态性能．     

Saturation throughput analysis of RTS/CTS scheme in an error-prone WLAN channel

In this paper, a new three-dimensional Markov model is proposed for the estimation of saturation throughput of RTS/CTS （request to send/clear to send） scheme in an error-prone wireless local area network （WLAN） channel. The model takes account of the effect of bit error on all the frames, and station short and long retry limits. Saturation throughput was re-analyzed using the new Markov model and numerical results closely matched those from simulation, confirming the accuracy of the new model. Evaluation of the influence of different parameters on throughput showed that the saturation throughput is sensitive to channel bit error rates and packet length, especially in high bit error conditions.