A Forecast Error Correction Method in Numerical Weather Prediction by Using Recent Multiple-time Evolution Data

The initial value error and the imperfect numerical model are usually considered as error sources of numerical weather prediction （NWP）. By using past multi-time observations and model output, this study proposes a method to estimate imperfect numerical model error. This method can be inversely estimated through expressing the model error as a Lagrange interpolation polynomial, while the coefficients of polyno- mial are determined by past model performance. However, for practical application in the full NWP model, it is necessary to determine the following criteria： （1） the length of past data sufficient for estimation of the model errors, （2） a proper method of estimating the term ＂model integration with the exact solution＂ when solving the inverse problem, and （3） the extent to which this scheme is sensitive to the observational errors. In this study, such issues are resolved using a simple linear model, and an advection diffusion model is applied to discuss the sensitivity of the method to an artificial error source. The results indicate that the forecast errors can be largely reduced using the proposed method if the proper length of past data is chosen. To address the three problems, it is determined that （1） a few data limited by the order of the corrector can be used, （2） trapezoidal approximation can be employed to estimate the ＂term＂ in this study; however, a more accurate method should be explored for an operational NWP model, and （3） the correction is sensitive to observational error.

Detecting Data-flow Errors Based on Petri Nets With Data Operations

In order to guarantee the correctness of business processes, not only control-flow errors but also data-flow errors should be considered. The control-flow errors mainly focus on deadlock, livelock, soundness, and so on. However, there are not too many methods for detecting data-flow errors. This paper defines Petri nets with data operations(PN-DO) that can model the operations on data such as read, write and delete. Based on PN-DO, we define some data-flow errors in this paper. We construct a reachability graph with data operations for each PN-DO, and then propose a method to reduce the reachability graph. Based on the reduced reachability graph, data-flow errors can be detected rapidly. A case study is given to illustrate the effectiveness of our methods.

Ocean Data Assimilation with Background Error Covariance Derived from OGCM Outputs

The background error covariance plays an important role in modern data assimilation and analysis systems by determining the spatial spreading of information in the data. A novel method based on model output is proposed to estimate background error covariance for use in Optimum Interpolation. At every model level, anisotropic correlation scales are obtained that give a more detailed description of the spatial correlation structure. Furthermore, the impact of the background field itself is included in the background error covariance. The methodology of the estimation is presented and the structure of the covariance is examined. The results of 20-year assimilation experiments are compared with observations from TOGA-TAO (The Tropical Ocean-Global Atmosphere-Tropical Atmosphere Ocean) array and other analysis data.

Handling Error Propagation in Sequential Data Assimilation Using an Evolutionary Strategy

An evolutionary strategy-based error parameterization method that searches for the most ideal error adjustment factors was developed to obtain better assimilation results. Numerical experiments were designed using some classical nonlinear models （i.e., the Lorenz-63 model and the Lorenz-96 model）. Crossover and mutation error adjustment factors of evolutionary strategy were investigated in four aspects： the initial conditions of the Lorenz model, ensemble sizes, observation covarianee, and the observation intervals. The search for error adjustment factors is usually performed using trial-and-error methods. To solve this difficult problem, a new data assimilation system coupled with genetic algorithms was developed. The method was tested in some simplified model frameworks, and the results are encouraging. The evolutionary strategy- based error handling methods performed robustly under both perfect and imperfect model scenarios in the Lorenz-96 model. However, the application of the methodology to more complex atmospheric or land surface models remains to be tested.

Data processing and error analysis for the CE-1 Lunar microwave radiometer

The microwave radiometer （MRM） onboard the Chang＇ E-1 （CE-I） lu- nar orbiter is a 4-frequency microwave radiometer, and it is mainly used to obtain the brightness temperature （TB） of the lunar surface, from which the thickness, temperature, dielectric constant and other related properties of the lunar regolith can be derived. The working mode of the CE-1 MRM, the ground calibration （including the official calibration coefficients）, as well as the acquisition and processing of the raw data are introduced. Our data analysis shows that TB increases with increasing frequency, decreases towards the lunar poles and is significantly affected by solar illumination. Our analysis also reveals that the main uncertainty in TB comes from ground calibration.

The Application of the GM(1,1) Metabolism Model to Error Data Processing of NC Machine Tools

This paper applied the gray system theory to error data processing of NCmachine tools according to the characteristic. It presented the gray metabolism model of error dataprocessing. The test method for the model needs less capacity. Practice proved that the method issimple, calculation is easy, and results are exact.

基于HCPN的复杂BPMN协作模型数据流建模与验证

为了保证复杂BPMN协作模型的正确性,不仅要涵盖多实例和子进程等复杂元素,还要在检测控制流错误的同时检测数据流错误。但业务流程建模标注(BPMN 2.0)缺乏形式化语义的描述,这对模型正确性的验证造成了阻碍。因此,给出了一种具有弧权重的层次化着色Petri网(HCPN)的定义,它既可以对数据流进行形式化表示,又可以对多实例和子进程结构进行建模。进一步提出了从BPMN协作模型到HCPN模型的形式化映射方法。然后基于HCPN模型的弧权重给出了缺失、丢失和冗余3种数据流错误的定义,并提出了对应的检测算法。最后,设计了一个自动化建模与验证的框架,通过一个案例研究说明了该方法的有效性。

Improvement in Background Error Covariances Using Ensemble Forecasts for Assimilation of High-Resolution Satellite Data

Satellite data obtained over synoptic data-sparse regions such as an ocean contribute toward improving the quality of the initial state of limited-area models. Background error covariances are crucial to the proper distribution of satellite-observed information in variational data assimilation. In the NMC （National Meteorological Center） method, background error covariances are underestimated over data-sparse regions such as an ocean because of small differences between different forecast times. Thus, it is necessary to reconstruct and tune the background error covariances so as to maximize the usefulness of the satellite data for the initial state of limited-area models, especially over an ocean where there is a lack of conventional data. In this study, we attempted to estimate background error covariances so as to provide adequate error statistics for data-sparse regions by using ensemble forecasts of optimal perturbations using bred vectors. The background error covariances estimated by the ensemble method reduced the overestimation of error amplitude obtained by the NMC method. By employing an appropriate horizontal length scale to exclude spurious correlations, the ensemble method produced better results than the NMC method in the assimilation of retrieved satellite data. Because the ensemble method distributes observed information over a limited local area, it would be more useful in the analysis of high-resolution satellite data. Accordingly, the performance of forecast models can be improved over the area where the satellite data are assimilated.

“数形结合”——测量及不确定度教学模式的改革与研究

理解测量的不确定度是大学物理实验课程一项重要的教学目标。在大学物理实验绪论课中,准备了两个版本的不确定性教学方式:即有无测量数据的图形化展示。课程结束后,对学生进行测试,研究数据的图形化展示是否能够提高学生对不确定度的理解。结果表明,有图形展示的班级学生比没有图形展示的班级学生得分更高。图形表示有助于数据的可视化,在进行测量数据分析时减少了学生的认知负荷,因此应该在教学中积极推广使用。

Accuracy Assessment and Guidelines for Manual Traffic Counts from Pre-Recorded Video Data

Traffic count is the fundamental data source for transportation planning, management, design, and effectiveness evaluation. Recording traffic flow and counting from the recorded videos are increasingly used due to convenience, high accuracy, and cost-effectiveness. Manual counting from pre-recorded video footage can be prone to inconsistencies and errors, leading to inaccurate counts. Besides, there are no standard guidelines for collecting video data and conducting manual counts from the recorded videos. This paper aims to comprehensively assess the accuracy of manual counts from pre-recorded videos and introduces guidelines for efficiently collecting video data and conducting manual counts by trained individuals. The accuracy assessment of the manual counts was conducted based on repeated counts, and the guidelines were provided from the experience of conducting a traffic survey on forty strip mall access points in Baton Rouge, Louisiana, USA. The percentage of total error, classification error, and interval error were found to be 1.05 percent, 1.08 percent, and 1.29 percent, respectively. Besides, the percent root mean square errors (RMSE) were found to be 1.13 percent, 1.21 percent, and 1.48 percent, respectively. Guidelines were provided for selecting survey sites, instruments and timeframe, fieldwork, and manual counts for an efficient traffic data collection survey.

高速铁路动静态轨检数据里程对齐与误差修正

轨道几何动、静检测数据间的精确匹配对探明高速铁路线路服役状态和制定准确可靠的养护维修策略具有关键作用。针对动静里程匹配算法研究较少的现状,提出利用动、静态实测数据波形匹配,建立基于互相关函数与动态时间规划相结合的两阶段修正算法,并以距离误差作为评价指标。结合某高铁线路轨道几何检测数据的案例分析,以静态检测数据作为参考基准,对动态检测数据进行里程误差评估与修正。结果表明,两阶段算法修正效果显著,累积距离误差降幅超过93%,修正后的动、静态检测数据严格对齐保证了动态检测数据的可靠性与有效性。

Estimation of Nonparametric Multiple Regression Measurement Error Models with Validation Data

In this article, we develop estimation approaches for nonparametric multiple regression measurement error models when both independent validation data on covariables and primary data on the response variable and surrogate covariables are available. An estimator which integrates Fourier series estimation and truncated series approximation methods is derived without any error model structure assumption between the true covariables and surrogate variables. Most importantly, our proposed methodology can be readily extended to the case that only some of covariates are measured with errors with the assistance of validation data. Under mild conditions, we derive the convergence rates of the proposed estimators. The finite-sample properties of the estimators are investigated through simulation studies.

数据错误的法律治理

大数据时代,数据错误普遍存在。数据错误贯穿数据的全生命周期,是数据质量低下的表现,主要包含缺乏时效、记录重复、难被理解、难以访问、可信度低、不成体系、不一致等特性,表现为数据损失、篡改、造假、偏差、混淆等形式。数据错误既包括客观实际层面的错误,也包括主观行为层面的错误,其成因在于数治制度、数治体系与数治能力存在缺陷。数据错误可能会损害公民的正当权利,破坏社会的运行秩序以及降低国家的治理效能。因此,要确定数据错误规制的基本原则,厘清规制数据错误的主要路径,构建规制数据错误的具体制度,包括设立必要的数据容错法律机制,建构维护数据质量的法律制度以及打造全链条协同共治的法律制度,从而更好地进行数据治理。

基于ARIMAX的区域飞行流量预测模型研究

随着航空业的迅速发展,航空公司、机场管理和空中交通管制对精确预测飞行流量的需求迅速增加,为此提出了基于自回归移动平均外生变量(ARIMAX)的区域飞行流量预测模型。通过分析广播式自动相关监视(ADS-B)数据,在自回归移动平均模型(ARIMA)的基础上引入航空器飞行距离间隔作为外生变量构建预测模型,将ARIMAX与LSTM、ARIMA的预测结果进行均方根误差(RMSE)及平均绝对百分比误差(MAPE)比较,由实验结果可知,该模型预测结果的RMSE及MAPE较LSTM分别降低了21.3架及1.2%,较ARIMA分别降低了29.9架及2.4%。

Bayesian estimator of human error probability based on human performance data

A Bayesian method for estimating human error probability（HEP） is presented.The main idea of the method is incorporating human performance data into the HEP estimation process.By integrating human performance data and prior information about human performance together,a more accurate and specific HEP estimation can be achieved.For the time-unrelated task without rigorous time restriction,the HEP estimated by the common-used human reliability analysis（HRA） methods or expert judgments is collected as the source of prior information.And for the time-related task with rigorous time restriction,the human error is expressed as non-response making.Therefore,HEP is the time curve of non-response probability（NRP）.The prior information is collected from system safety and reliability specifications or by expert judgments.The（joint） posterior distribution of HEP or NRP-related parameter（s） is constructed after prior information has been collected.Based on the posterior distribution,the point or interval estimation of HEP/NRP is obtained.Two illustrative examples are introduced to demonstrate the practicality of the aforementioned approach.

压差式流量计误差自动化修正算法研究

针对在多干扰源扰动下压差式流量计测量结果面临输出不稳、误差较大的问题,提出多源扰动下的压差式流量计误差自动化修正算法。考虑全补偿气体可膨胀性系数、压缩系数、密度系数和流出系数等因素,研究压差式流量计误差自动化修正算法。利用均值滤波滤除信号中的高斯噪声,结合一阶滞后滤波优化卡尔曼滤波算法,修正多源扰动误差。引入自组织算法和Volterra神经网络进一步改进卡尔曼滤波算法,并优化卡尔曼滤波算法的先验模型参数,以实现多源扰动误差的自动化修正。试验结果表明,经该算法控制后:当参考流量为900 m^(3)/h时,示值误差绝对值为0.203%;当参考流量为700 m^(3)/h时,流量计重复性为0.06%。该研究可以有效识别并修正由于多源扰动造成的流量异常值,且流量测量精度较高。

Orthogonal Series Estimation of Nonparametric Regression Measurement Error Models with Validation Data

In this article we study the estimation method of nonparametric regression measurement error model based on a validation data. The estimation procedures are based on orthogonal series estimation and truncated series approximation methods without specifying any structure equation and the distribution assumption. The convergence rates of the proposed estimator are derived. By example and through simulation, the method is robust against the misspecification of a measurement error model.

基于ECOC平衡随机森林的雷达降水粒子分类

针对数据不平衡情况下的降水粒子分类问题,提出了一种基于纠错输出码(error correcting output code,ECOC)平衡随机森林的双偏振气象雷达降水粒子分类方法。首先,将多类别降水粒子数据集编码为多个二分类数据集;然后,对二分类数据集进行有放回的平衡重采样,构建多棵分类回归树;最后,利用所有的分类回归树联合进行降水粒子分类。对实测数据的处理结果表明,所提方法能够在保证总体准确率较高的情况下,大幅提高少数类的分类效果。

用于数据采集器测试的时间脉冲插值分析方法

地震数据采集器时间服务精度是评价设备性能的重要指标,一般使用标准时间源输出的时间脉冲信号采样数据进行分析计算,但受仪器采样率限制,时间偏差测试分辨率不高。设计了基于一阶差分和直方图分析的脉冲信号上升沿识别、高低电位分析和时间偏差分析算法,研究使用非线性插值分析方法对地震数据采集器采集的标准时间脉冲信号进行波形升采样恢复,并基于所提算法进行实验分析和讨论,在提高地震数据采集器时间偏差测试分辨率的同时,规范了测试数据处理方法和流程。