信号的直接采样理论

经典的采样定理建立了带限信号与其均匀采样值之间的联系。本对采样定理作了三点补充：（1）给出在定理条件不满足时，由均匀采样值恢复的信号与原信号的误差表达式；（2）用简洁的方法分析了带通信号的均匀采样问题，得到了采样率应满足的条件；（3）研究了一种特殊的非均匀采样情况，给出了采样率的可取范围以及由非均匀采样重构原信号的公式。进一步丰富和深化了经典的采样定理。     

具有最少采样点的圆度误差测量研究

建立了采样点均匀分布情况下，圆度误差测量采样点数量与测量极限误差之间的定量关系数学模型。根据所得数学模型，对测量坐标值原则下给定圆度误差检测对象的采样点进行规划，求得具有最少采样点的测量方法，并给出了测量实例，对数学模型进行了验证。     

采样信号频率偏离设计值情况下离散傅立叶变换的误差分析

通过理论推导和数字仿真，从本质上揭示了被采样信号频率发生波动时离散傅立叶变换（DFT）计算结果的误差根源，给出了相对误差表达式，对误差曲线进行了定性分析；本文结论对减小DFT误差的研究具有一定的指导意义。     

采样定理研究

采样定理是数字信号处理的基础,在信号的理论研究和工程实践中都有重要而广泛的应用.给出了采样定理的一个新的推导方法,研究了重构信号与原信号之间的关系,建立了相应的误差公式.同时,进一步研究了不同采样频率下采样信号之间的关系,得到了采样信号之间的转换公式.     

数字信号处理中的DFT与CFT的关系

本文从时域采样定理、频域采样定理的角度出发分析了离散傅里叶变换(DFT)和连续傅里叶变换(CFT)之间的关系，推导出DFT的数学表达式。并以实例讨论了DFT近似连续傅里叶变换的误差情况，对如何合理选择抽样点数也给出了详细论述。     

基于MATLAB的信号采样与重构的实现

该文基于MATLAB再现了连续信号的采样频谱和重构的时域信号,给出了信号重构的误差,并分析了采样周期对采样频谱叠加和信号重构精度的影响。     

虚拟仪器在评定直线度误差实验教学中的应用

针对互换性与技术测量课程中实验教学存在效率低、功能单一的问题,在评定直线度误差实验中引入虚拟仪器技术,通过虚拟仪器设计的测量仪具有采集、存储、分析处理功能,采用LabVIEW作为软件开发平台,对直线度误差中两端点法、最小二乘法和最小区域法3种评定方法给出了相应的评定结果,可显示采样点的偏差值、轮廓曲线及直线度误差,实现了直线度误差可视化测量评定,使学生能直观地理解检测评定原理。     

对集装箱外运商品煤采样方法的研究及应用

针对集装箱采样没有统一标准，采样结果误差较大的情况；参照国家标准中汽车外运商品煤的三点循环采样法，在一点法的基础上，通过逐次增加采样子样数，作对比试验，选取与准确值最为接近的五点循环法作为集装箱的采样方法；运用五点循环法进行采样精密度实验，并对实验数据进行数理统计分析，统计结果表明，五点循环法能够达到采样精密度核对规定要求；集装箱五点循环法已在全集团公司进行了推广，取得了较大的经济和社会效益。     

微机数据采集在实验中的应用

介绍微机数据采集系统的组成和应用。利用汇编语言和BASIC语言的混合编程，结合8253可编程定时器精确控制采样时间可实现高速精密数据采集，通过高级语言与低级语言的数据交换，使整个数据采集系统从采样频率到数据量均可实现程序控制及高质量的数据处理。针对正弦信号的频率测量及电容量测量，给出测量方法和数据处理方法，并对测量结果进行误差分析。     

具有单集值点的分段严格递增集值映射的迭代根

在进行数据分析时用集值映射代替传统的单值映射可以有效减少误差，因此关于集值映射的研究是十分重要的.前人已讨论了全局单调上半连续且有有限个集值点的集值映射的迭代根问题，现在进一步研究分段严格递增的单集值映射的迭代根问题并给出了迭代根的构造.     

Generalizability of Performance Assessments

How can the contributions of raters and tasks to error variance be estimated? Which source of error variance is usually greater? Are interrater coefficients adequate estimates of reliability? What other facets contribute to unreliability in performance assessments?     

The nature of error in adolescent student writing

This study examined the nature and frequency of error in high school native English speaker (L1) and English learner (L2) writing. Four main research questions were addressed: Are there significant differences in students’ error rates in English language arts (ELA) and social studies? Do the most common errors made by students differ in ELA and social studies? Are there significant differences in the error rates between L1 and L2 students in ELA? Do L1 and L2 students differ in how frequently they make the most common errors in ELA? Written work of 10th and 12th grade students in five states was collected. The sample included 178 essays (120 in ELA and 58 in social studies) from 67 students (33 10th graders and 34 12th graders; 49 native English speaking students and 18 English learners). Results indicate that there were significant differences in the frequencies of errors between ELA and social studies, with higher error rates in social studies. In addition, L2 writers had significantly higher error rates than L1 writers in ELA. Aside from a few types of errors (spelling, capitalization, and some punctuation errors), most types of errors appear relatively infrequently in school-sponsored writing. Moreover, the eight most common errors accounted for a little more than half of all errors, and these did not differ significantly between ELA and social studies writing or between L1 and L2 writers.     

An Experimental Design of a Study on Meta-Cognitive Strategy with the Perspective of Error Analysis in Listening Training

Though abundant work has been done in both metacognitive strategy and error analysis,less has been done in the exact execution model of applying meta-cognitive strategy with the perspective of error analysis. This study explored the construction of an integrative execution model of meta-cognitive strategy with the perspective view of error analysis. This thesis involves 2 research questions: 1) Will the training of applying meta-cognitive strategies with the help of error analysis improve students' listening performance signifi cantly? 2) If any,will this improvement signifi cantly correlated to students' conscious application of metacognitive strategies with the help of error analysis?     

基于Fisher的线性判别回归分类算法

为了提高线性回归分类（LRC）算法的鲁棒性,提出了一种基于Fisher准则的线性判别回归分类算法。利用Fisher准则将类间与类内重建误差的比值最大化,找到线性回归分类的最优投影矩阵;再将训练图像及测试图像投影到各类的特征子空间;求得各训练图像与测试图像间的欧氏距离,最后用K-近邻分类器完成人脸识别。在AR人脸数据库上的实验结果表明,相比其他回归分类算法,算法取得了更好的识别效果。     

Selection of Judges for Standard-Setting

Who should make judgments about test standards? Who is an expert? How many judges should be used in a standard-setting study? What is the relationship between the number of judges and the standard error of the test?     

Cooperative learning as a correction and grammar revision technique： Communicative exchanges, self-correction rates and scores

This paper focuses on cooperative learning （CL） used as a correction and grammar revision technique and considers the data collected in six Italian parallel classes, three of which （sample classes） corrected mistakes and revised grammar through cooperative learning, while the other three （control classes） in a traditional way. All the classes involved in this study were in their first year of secondary school, and although most students had a level of English which was A2, they made a certain number of mistakes also in grammar topics like the present tense, which is the grammar topic under examination in this study. This paper analyses the sample students＇ communicative exchanges while they performed the error correction activity through CL, compares the self-correction rates reported by the two groups of students after the two types of correction and revision activities （traditional and through CL） and the students＇ scores in tests given to students one, four and eight weeks after the correction lessons. The aim of the study is establishing if the use of CL as a correction and grammar revision technique had a beneficial effect on the students who experienced it and in particular on the low achievers.     

Quadratic radical function better than fisher z transformation

A new explicit quadratic radical function is found by numerical experiments, which is simpler and has only 70.778% of the maximal distance error compared with the Fisher z transformation. Furthermore, a piecewise function is constructed for the standard normal distribution： if the independent variable falls in the interval （-1.519, 1.519）, the proposed function is employed; otherwise, the Fisher z transformation is used. Compared with the Fisher z transformation, this piecewise function has only 38.206% of the total error. The new function is more exact to estimate the confidence intervals of Pearson product moment correlation coefficient and Dickinson best weights for the linear combination of forecasts.     

Reading and spelling error analysis of native

This study was an investigation of reading and spelling errors of dyslexic Arabic readers (n=20) compared with two groups of normal readers: a young readers group, matched with the dyslexics by reading level (n=20) and an age-matched group (n=20). They were tested on reading and spelling of texts, isolated words and pseudowords. Two research questions were the focus of this study: What are the reading and spelling profile errors of dyslexic native Arabic speakers? What is the effect of the Arabic orthography on these types of errors? The results of the reading error analysis revealed a clear contribution of the uniqueness of the Arabic orthography to the types of errors made by the three different groups. In addition, the error profiles of the dyslexic readers were similar to the error profiles made by the younger reading-level-matched group in percentages and in quality. The most prominent types of errors were morphological and semiphonetic, which highlighted the contribution of the Arabic orthography to these types of errors. Consistently, the profile of the spelling errors was similar in percentages and quality among the dyslexics and the reading-level-matched group but different from the age-matched group on the spelling measures. The analysis of the spelling errors revealed that the dominant type of error was mostly phonetic due to the limited orthographic lexicon. In addition, the Arabic orthography also contributed to these types of errors because many spelling mistakes were made due to poor knowledge of the spelling rules. The results of the reading and spelling errors are discussed from a reading development point of view. Further, two models are suggested, one for reading and one for spelling, to illustrate the cognitive processes that underlie the reading and spelling mistakes in this type of orthography.     

基于长短期记忆网络的工业空调启动时间预测

为了降低企业生产车间空调能耗,基于长短期记忆（LSTM）网络构建了一种工业空调启动时间预测模型。使用该模型对车间空调提前启动时间进行预测,并将预测结果应用于车间空调系统的启动控制,以达到节能目的;采用平均绝对百分误差（MAPE）对预测模型进行整体误差评估,实验结果表明：LSTM 较好地解决了生产车间空调系统启动时间预测问题,相较于传统预测方法有着更小的 MAPE。优化控制后的空调系统能够在保证车间生产环境达标的同时,降低空调系统约 27.9%的能耗。     

Optimal design on wideband directional coupler

Combining the modified Bethe small holes coupling theory with McDonald thickness theory and field averaging correction factor, it is accurate to design the weak coupling waveguide directional coupler. While the coupling is tight, the decrease of the field strength in the main waveguide caused by aperture should not be neglected. For a −6 dB directional coupler is described in this article, the theoretical value of coupling is good agree to the simulation value, by simulated and optimized with the professional software computer simulation technology (CST). In the designed waveband, the error of coupling between theoretical value and simulating one is less than 0.25 dB. The error of coupling between simulation value and designed value is less than 0.5 dB. To improve the isolation, some spaces between two adjacent holes are turned from the traditional ? centre guided wavelength. The performance of isolation has 5 dB improvement, and length of the coupling area is only 51.06 mm.