共查询到20条相似文献，搜索用时 203 毫秒
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目前对三维激光扫描的分析主要停留在误差模型的建立上,没有对三维激光扫描仪的特点及其所受的误差进行分析,而三维激光扫描仪的系统误差和偶然误差都将会对整个误差模型的建立产生影响,点位误差源的准确分析是点位准确建立点位误差模型的基础。基于此,本文对三维激光扫描仪的点位误差源进行了分析,得到了不同误差源的误差模型,并给出了不同条件可能对激光扫描仪误差影响的大小。 相似文献
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针对单频GPS接收机受空间环境误差影响较大的特点,系统地分析了空间环境误差特性在GPS导航中造成的定位误差。详细介绍了空间环境误差的两个典型的误差模型,即Klobuchar模型和Hopfield模型。并通过卫星信号模拟器进行实验,在不考虑空间环境误差模型和考虑空间环境误差模型后得到的数据进行分析,结果表明了考虑空间环境误差模型后,导航定位精度在有很大的提高,从而也验证了空间环境模型在实际应用上是可行的。 相似文献
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目前,在对三维激光点位误差模型进行推导的过程中,都是假设三维激光点位误差是服从正态分布的,而由于三维激光点位误差源与传统测量仪器中的误差源不同,同时外界环境对激光点位误差的影响也不相同,因此,不能直接断定点位误差服从正态分布,需要对其理论分析及数据统计分析验证。针对三维激光点位误差分布状况,本文对激光点位误差模型进行了推导,并通过大量数据统计分析验证了激光点位误差服从的分布状况。 相似文献
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原油动态计量是原油贸易交接的主要方式，使用的计量器主要是容积式流量计。本文着重从误差的来源分析了用容积式流量计进行原油计量产生误差的原因，解释了体积管保温、安装自动取样器和自动含水分析仪的必要性。最后从人员误差、装置误差、环境误差和方法误差这四个方面来降低原油交接中计量误差的方法。 相似文献
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本文首先光电测距仪周期误差的概念、来源以及相位式光电测距仪周期误差的理论计算公式进行了分析,之后利用平台法对光电测距仪周期误差进行了计算分析,把周期误差曲线分解为各次谐波的叠加,求出各次谐波的振幅、初相,进而求出观测值中误差,初步揭示周期误差的实质。 相似文献
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分析了测量学误差传播定律研究的意义,总结了测量学误差传播定律研究的成果,指出测量学误差传播定律的研究方向,并为测量学误差传播定律的进一步研究起到基础作用。 相似文献
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管输油料计量交接误差的可控性对监控管线安全和经营安全有着重要意义。本文以调查实例分析了管输油料的计量交接误差。结果表明误差的产生是多种因素造成的,其中计量方法所产生的误差是主要因素,测量器具所产生的误差是次要因素。根据对误差产生原因的分析,提出了降低管输油料交接计量误差的措施。 相似文献
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Shigen Gao Hairong Dong Bin Ning Hongwei Wang 《Journal of The Franklin Institute》2018,355(13):5452-5474
In this paper, a novel error-driven nonlinear feedback technique is designed for partially constrained errors fuzzy adaptive observer-based dynamic surface control of a class of multiple-input-multiple-output nonlinear systems in the presence of uncertainties and interconnections. There is no requirements that the states are available for the controller design by constructing fuzzy adaptive observer, which can online identify the unmeasurable states using available output information only. By transforming partial tracking errors into new error variables, partially constrained tracking errors can be guaranteed to be confined in pre-specified performance regions. The feature of the error-driven nonlinear feedback technique is that the feedback gain self-adjusts with varying tracking errors, which prevents high-gain chattering with large errors and guarantees disturbance attenuation with small errors. Based on a new non-quadratic Lyapunov function, it is proved that the signals in the resulted closed-loop system are kept bounded. Simulation and comparative results are given to demonstrate the effectiveness of the proposed method. 相似文献
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This paper demonstrates that the vast majority of spelling errors follow specific rules which are based on phonological and sequential considerations. It introduces and describes three categories of spelling errors (consonantal, vowel and sequential) and presents the results of the analysis of 1377 spelling error forms. 相似文献
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Yang Chi-Ching 《Journal of The Franklin Institute》2012,349(1):349-365
By taking account of uncertain slave system parameters, the main goal of this paper is to investigate exponential master–slave synchronization between two nearly identical generalized Lorenz systems via one control input, which including a single state proportional feedback, associated with system parameter estimated laws, which not including states of the master system. Sufficient conditions are provided for the guaranteed exponential stability of both synchronized errors and system parameter errors. Meanwhile, numerical studies are also performed to verify the effectiveness of presented schemes. 相似文献
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泰国留学生在书面语里出现的偏误现象分为以下几个类型：复句的逻辑性偏误、程度副词偏误、遗漏偏误、增补偏误、语法规则偏误等。外国学习者所产生的偏误大体上都是基于“五个中心过程”理论而形成的。偏误的产生是正常的,偏误分析的作用就在于针对汉语自身的特点分析、归纳、总结习得者的习得规律,从而提高对外汉语的教学效果。 相似文献
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本文对采用一般的工业套管式热电偶温度计测量过热器前的烟气温度时,存在着的测量误差,就35T/h循环流化床锅炉的一个实例对测温感受件进行了热平衡计算。并计算与讨论了各种有关因素对测量误差的影响。同时对可能采取用来降低测量误差的技术措施,作了现场测量与分析。 相似文献
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Annalise E. Zemlin 《Indian journal of clinical biochemistry : IJCB》2018,33(2):154-162
The total testing process consists of various phases from the pre-preanalytical to the post-postanalytical phase, the so-called brain-to-brain loop. With improvements in analytical techniques and efficient quality control programmes, most laboratory errors now occur in the extra-analytical phases. There has been recent interest in these errors with numerous publications highlighting their effect on service delivery, patient care and cost. This interest has led to the formation of various working groups whose mission is to develop standardized quality indicators which can be used to measure the performance of service of these phases. This will eventually lead to the development of external quality assessment schemes to monitor these phases in agreement with ISO15189:2012 recommendations. This review focuses on potential errors in the extra-analytical phases of clinical chemistry laboratory testing, some of the studies performed to assess the severity and impact of these errors and processes that are in place to address these errors. The aim of this review is to highlight the importance of these errors for the requesting clinician. 相似文献
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《Journal of The Franklin Institute》2023,360(13):10297-10336
Owing to the effect of measurement noise and sudden changes in the power system, the robustness of state estimation for power system becomes very important. The Unscented Kalman Filter (UKF) is widely used for state estimation. However, it does not consider the influence of different kinds of gross errors. To better deal with gross errors, a robust adaptive UKF with gross error detection and identification (RAUKF-GEDI) is proposed, which uses the robust generalized correntropy loss in the UKF framework. The RAUKF-GEDI detects gross errors by hypothesis testing, and then uses the moving window to identify and classify three kinds of gross errors. Subsequently, the RAUKF-GEDI estimates the magnitudes of the gross errors to further compensate the measurements, and finally uses the compensated measurements to re-estimate the state to obtain precise estimated states. In addition, RAUKF-GEDI also introduces adaptive covariance matching method for state estimation. The RAUKF-GEDI is applied to the state estimation for power systems where the measurements are contaminated by three kinds of gross errors. Finally, the RAUKF-GEDI is also applied to the practical power system of Zhejiang Juchuang Smart Technology Company Park. The results show that the RAUKF-GEDI can detect and identify gross errors and enhance the robustness of UKF. 相似文献
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Sweta Kulkarni R. Ramesh A. R. Srinivasan C. R. Wilma Delphine Silvia 《Indian journal of clinical biochemistry : IJCB》2018,33(1):102-107
Preanalytical steps are the major sources of error in clinical laboratory. The analytical errors can be corrected by quality control procedures but there is a need for stringent quality checks in preanalytical area as these processes are done outside the laboratory. Sigma value depicts the performance of laboratory and its quality measures. Hence in the present study six sigma and Pareto principle was applied to preanalytical quality indicators to evaluate the clinical biochemistry laboratory performance. This observational study was carried out for a period of 1 year from November 2015–2016. A total of 1,44,208 samples and 54,265 test requisition forms were screened for preanalytical errors like missing patient information, sample collection details in forms and hemolysed, lipemic, inappropriate, insufficient samples and total number of errors were calculated and converted into defects per million and sigma scale. Pareto`s chart was drawn using total number of errors and cumulative percentage. In 75% test requisition forms diagnosis was not mentioned and sigma value of 0.9 was obtained and for other errors like sample receiving time, stat and type of sample sigma values were 2.9, 2.6, and 2.8 respectively. For insufficient sample and improper ratio of blood to anticoagulant sigma value was 4.3. Pareto`s chart depicts out of 80% of errors in requisition forms, 20% is contributed by missing information like diagnosis. The development of quality indicators, application of six sigma and Pareto`s principle are quality measures by which not only preanalytical, the total testing process can be improved. 相似文献
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双频雷达高度计电离层色散效应误差分析 总被引：1，自引：0，他引：1
由于现代星载雷达高度计采用了脉冲压缩技术，引入了电离层色散误差，在双频高度计的低频段该误差更明显。本文基于全去斜技术的理论模型，推导了这项误差的机理，提出可以把该误差等效为二次相位误差，并结合具体参数给出了分析的结果。本文还讨论了Chirp信号的多普勒误差对测高的影响。最后，作者通过计算机仿真得到了电离层色散效应对系统点目标响应的影响,对前面的结论进行了验证。 相似文献