查询词典 error estimation

When the random error is not subject to normal distribution, the least absolute deviation estimation is superior to the least squares estimation. In addition, the robustness of the least absolute deviation estimation is also better than that of the least squares estimation.

在随机误差不服从正态分布的问题中，最小一乘估计的统计性能优于最小二乘枯计；另外，最小一乘估计的稳健性更强。

An improved derivative estimation algorithm with a low-pass filter that can suppress the influence of high-frequency noise is suggested to remove potential drawbacks of the backward difference that was applied in neural network inversion dynamic compensation method, such as large estimation error in the presence of noise and price increase of hardware realization when high estimation accuracy is required.

针对神经网络逆动态补偿策略中基于向后差分的微分估计算法在噪声环境下存在较大的微分估计误差，且提高估计精度会增加硬件成本等缺陷，提出了改进的微分估计算法，并以加速度传感器为例，设计了动态补偿实验装置，给出了基于改进的微分估计算法的动态补偿算法的实现步骤。

to reduce the impact of carrier frequency offset in ofdm system,this thesis designs a new carrier frequency offset estimation scheme for ofdm system.the carrier frequency offset estimation includes acquisition and tracking.we adopt variable step size adaptive algorithm.the acquisition range of the proposed algorithm is as large as one half of the overall signal bandwidth.through this method we can not only avoid the feedback by using forward error correction,but also reduce the times of complex multiplication in order to reduce the power consumption of the system.this algorithm not only has low complexity and fast convergence nut also can improve the demodulation performance of ofdm system.computer simulation illustrates the superior performance of the proposed algorithm with regard to estimation accuracy in both awgn channel and multi—path channel.

摘 要：为了减小正交频分复用系统受频率偏差的影响，在ofdm系统中设计了一种新的载波频偏估计算法。频偏估计包括跟踪和捕获两个阶段，文中采用变步长自适应算法来进行跟踪，这个跟踪算法的捕捉范围是整个信号带宽的一半。通过此方法，不但可以利用前向纠错的方式来避免反馈，而且可以缩减复数乘法的次数以降低计算复杂度和系统功耗。该方法运算复杂度低，并具有较好的收敛性，能改善odfm的解调性能。从计算机的仿真效果可以看出无论是在awgn信道上还是在多径信道上都表现出了卓越的性能。

As steady error coefficient is an important index in measuring system error, it is introduced into the performance index set. A solution of satisfactory biased estimation strategy is proposed by assuming that the maneuver of target is finite, which can ensure the accuracy and stability of the estimation output.

稳态误差系数是衡量系统误差的一个重要指标，于是本文将估计系统的动态误差系数纳入多指标约束，借助满意估计理论，在假定目标机动强度有限的前提下，给出了可兼顾滤波输出精度和平稳性要求的满意有偏滤波器的设计方法。

Normal vectors, Gaussian and mean curvatures estimation are obtained by different curvatures estimation methods, and the error is computed by comparing estimation results with real ones on the sphere of unit radius and toms.

在单位球面和环面上，利用不同的曲率估计方法得到法向量以及高斯曲率，平均曲率的估算值，再将估算值与实际值做比较求误差。

In addition, error resource existing in rotor position estimation algorithm is analyzed comprehensibly, therefore, some further work is made to eliminate the negative influence from errors. In this research, additional function is added to rotor position estimation algorithm to enhance precision of position estimation and its feasibility has been proved.

根据已有的无位置传感器转子位置检测原理，提出了两种改进的检测方法：一是改进电感法的检测方法，并设计了检测电路；二是根据SR电机的ψ-I-θ关系，研究了基于模糊推理规则的间接转子位置估算方法，分析了估算过程中存在的误差源，研究了提高估算精度的策略。

As a differential detection is used between the intercarrier, the proposed algorithm overcome the high sensitivity to timing error of conventional algorithm and is robust to multi-path. The effect of sample frequency offset can't be ignored in a continuous OFDM system of a large number of subcarriers. The estimation precision of the conventional algorithm is low and the realization is complex. A joint estimation of sample frequency offset and fine frequency offset based on difference operation is proposed. As averaging use a large number of samples in a maximum likelihood algorithm, the estimation precision is very high. The use of difference operation cancel the effect of carrier frequency offset, and the proposed sampling frequency estimation algorithm is robust to carrier frequency offset.

最后，本文对连续系统中的采样频率和载波频率精同步技术进行较为深入的研究，由于子载波数目大的连续OFDM传输系统中，采样频率偏差不可忽视，以往的采样频率估计方法精度低、实现复杂，因此本文提出了一种基于差分处理的采样频率偏差和精载波频率偏差联合估计算法，利用了最大似然算法进行采样频率偏差的估计，由于采用了差分处理方法，消除了载波频率偏差对采样频率偏差估计的影响，采用的最大似然算法对大量样点进行平均化处理，所以，相对以往算法，提出的联合算法估计精度高，而且采样频率偏差估计对载波频率偏差具有鲁棒性。

The estimation of forming part"s sideline The estimation of forming part"s sideline is significant in weld and assembly process, the paper puts forth two kinds of method to realize quantitative analysis for the deformed sideline, one is using line contour error to estimate deformed sideline combined with GA and taking the value of line contour error as target to check whether it is in the range of precision; The other is comparing curvature and torsion of design model with curvature and torsion of deformed model to check the sidelines precision.

冲压件边线变形的评价。冲压件的边线变形的评价在焊装工艺中有着重要意义，本文提出两种方法来实现冲压件边线的变形评价：一是借鉴线轮廓度评定的方法，结合遗传算法计算出边线的线轮廓度，并以线轮廓度值作为边线是否满足要求的评价指标：二是通过比较变形前后曲线的曲率和挠率来评价边线的变形情况。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

In this paper, a Minimum Mean Square Error based joint multi-cell channel estimation algorithm is proposed. By including the strong interfering users of adjacent cells into the channel estimation matrix, the noise power is significantly reduced which guarantees more precise channel estimation.

该文提出基于最小均方误差准则的联合多小区信道估计算法，由于改变了信道估计矩阵的结构，将邻小区强干扰用户也作为可以检测的用户信号来处理，降低了信道估计中噪声功率。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。