Digital zenith telescope prototype of China

Classical optical astronomy measures the direction of the local plumb line on the stellar background, and is influenced by variations of the earth gravity field. Therefore, classical optical astrometry can be used to measure and study variations of plumb line. This endows classical optical astrometric technologies special signifi- cance for the interdisciplinary researches of astronomy and geoscience, and makes them irreplaceable by technologies like very long baseline interferometry, satellite laser ranging. However, classical astrometric instruments have a major drawback of low efficiency, such as the low auto- maticity, more operating observers, and even operative error which makes it very difficult to reduce the random observation error in some visual instruments. To overcome this drawback, we have successfully developed the digital zenith telescope prototype （DZT-1） with the aperture of 200 mm, using charge coupled device and other advanced technologies and new equipments. As proved by test observations, DZT-1 can observe thousands of stars over one night, which significantly reduces the random obser- vation error and increases the observation accuracy. In addition, DZT-1 has a high degree of automation, even allowing unattended observation by remote control. Besides, DZT-1 has a small-size and is easy to move, making it convenient for mobile measurement of thedeflection of the vertical. In summary, DZT can be widely used in the geoscience and astronomy fields.     

A Novel Multi-Points Laser Monitoring of Building Settlement and Its Risk Evaluation

Aiming at the defects of routine settlement measurement methods, such as complicated procedures, time-consuming and labor-intensive, high cost and low measurement accuracy, based on the analysis of existing engineering measurement technical requirements and specifications, a multi-point high precision and high efficiency based on laser reference is proposed. The automatic building settlement real-time monitoring system program gives the principle and system model of single-point settlement observation. The model of multi-point scanning settlement monitoring system and the model of multi-point network settlement monitoring system are designed, and their advantages and disadvantages are analyzed. We focus on the networked multi-point settlement monitoring system for network cumulative error analysis, and propose related evaluation and correction methods. The hardware schematic and software block diagram of the laser reference measurement and measurement system of the single point settlement acquisition system are given. Finally, the risk of subsidence state is quantitatively evaluated based on multi-point settlement monitoring data. The measurement error of this method is less than 300 μm, which can realize the monitoring and evaluation of the overall settlement.     

Numerical study of unsteady cavitation on 2D NACA0015 hydrofoil using free/open source software

The free/open source software as OpenFOAM, Salome meshing and python language under Debian Linux system are evaluated to model unsteady cavitating turbulent flow around a NACA0015 hydrofoil. Based on the cavitation model proposed by Kunz and large eddy simu- lation （LES） method, we denote the benefits of free software and open source tools as an alternative to proprietary software of computational fluid mechanics, and provided a modified cavitation model to improve numerical accuracy. The simulation results of typical break-off cycle for cavitation shedding are compared to available experimental data, and validated using image processing to find percentage of similarities. The sheet cavity frequency of 7.752 Hz was obtained based on cavitation evolution and pressure fluctuations. The study gives relevant information for CFD software development in the future.     

Progress of research on anomalies of astronomical time and latitude observations before earthquake

This paper introduces the discovery of the phenomenon that short-term anomalous fluctuations appeared in residuals of astronomical time and latitude observations before earthquakes and the progress of related researches carried out for many years.The relations between the anomalous variations of time and latitude residuals of astronomical time and latitude instruments in different regions and the earthquakes around these instruments as well as the characteristics of residuals’ anomalous variations are analyzed.The significance of the anomalous fluctuations in residuals of astronomical time and latitude caused by the anomalous variations of the local plumb line before earthquake and detecting the vertical variation with astronomical time and latitude observations as well as the importance of carrying out further researches are discoursed.The possibility that the phenomenon will become an effective short-term earthquakes precursor,the current situations and the problems to be solved,are discussed.Also we offer the proposals to develop new roboticized astrometric instruments with high-precision and set up test observation networks in earthquake-prone areas in order to do research in-depth,optimize methods of observing and extracting anomalous information for short-term earthquake prediction,and so on.     

Classification of vegetation in North Tibet Plateau based on MODIS time-series data

Based on the 16d-composite MODIS （moderate resolution imaging spectroradiometer）-NDVI（normalized difference vegetation index） time-series data in 2004, vegetation in North Tibet Plateau was classified and seasonal variations on the pixels selected from different vegetation type were analyzed. The Savitzky-Golay filtering algorithm was applied to perform a filtration processing for MODIS-NDVI time-series data. The processed time-series curves can reflect a real variation trend of vegetation growth. The NDVI time-series curves of coniferous forest, high-cold meadow, high-cold meadow steppe and high-cold steppe all appear a mono-peak model during vegetation growth with the maximum peak occurring in August. A decision-tree classification model was established according to either NDVI time-series data or land surface temperature data. And then, both classifying and processing for vegetations were carried out through the model based on NDVI time-series curves. An accuracy test illustrates that classification results are of high accuracy and credibility and the model is conducive for studying a climate variation and estimating a vegetation production at regional even global scale.     

Satellite orbit determination by transfer with differenced ranges

The original idea of orbit determination called "determination of satellite orbit by transfer" was proposed by the National Time Service Center,Chinese Academy of Sciences.It shows that the system is very stable and the orbit determination accuracy is improved greatly.A new observation mode called "differenced ranges between master station and slave stations by transfer" is introduced.It is the development of "determination of satellite orbit by transfer".In principle,the differenced ranges between master station and slave stations have a high angular resolution,and strongly constrains in the transverse direction of satellite orbit,perpendicular to the line-of-sight.The principle of "differenced ranges between master station and slave stations by transfer" is discussed in detail.And differenced ranges in combination with ranging data were used to determine satellite’s orbit and orbit prediction under different arc observations.It shows that orbit determination accuracy for orbit prediction can be improved with differenced ranges in combination with ranging data.     

Development of a Chinese land data assimilation system:its progress and prospects

The objective of land data assimilation is to merge multi-source observations into the dynamics of land surface model for improving the estimation of land surface states.We have developed a land data assimilation system for China's land territory.In this sys- tem,the Common Land Model and Simple Biosphere Model 2 are used to simulate land surface processes.The radiative transfer models of thawed and frozen soil,snow,lake,and vegetation are used as observation operators to transfer model predictions into estimated bright- ness temperatures.A Monte-Carlo based sequential filter,the ensemble Kalman filter,is implemented as data assimilation method to inte- grate modeling and observation.The system is capable of assimilating passive microwave remotely sensed data such as special sensor mi- crowave/imager (SSM/I),TRMM microwave imager (TMI),and advanced microwave scanning radiometer enhanced for EOS (AMSR- E) and the conventional in situ measurements of soil and snow.A spatiotemporally consistent assimilated dataset for soil moisture,soil temperature,snow and frozen soil,with a spatial resolution of 0.25 degree and temporal resolution of one hour,has been produced.This paper introduces the development of Chinese land data assimilation system and the progress made on data assimilation algorithms,land sur- face modeling,microwave remote sensing of land surface hydrological variables,and the preparation of atmospheric forcing data.The dis- tinct characteristics and challenges of developing land data assimilation system and the perspectives for future development are also dis- cussed.     

Interoperability for Global Observation Data by Ontological Information

The Ontology registry system is developed to collect, manage, and compare ontological information for integrating global observation data. Data sharing and data service such as support of metadata deign, structuring of data contents, support of text mining are applied for better use of data as data interoperability. Semantic network dictionary and gazetteers are constructed as a trans-disciplinary dictionary. Ontological information is added to the system by digitalizing text based dictionaries, developing "knowledge writing tool" for experts, and extracting semantic relations from authoritative documents with natural language processing technique. The system is developed to collect lexicographic ontology and geographic ontology.     

A DEVELOPMENT OF MICROCOMPUTER-BASED MULTICHANNEL DIGITAL THERMOMETER

In this paper, the construction and performance of the microprocessor-based multi-chan-nel digital thermometric instrument together with its deisgn and fabrication are systematicallydescribed. The principle, method and practical softwares for the entire reference-junction com-pensation processing by microcomputer and the linearization of the characteristic ofthermocouples are also exhaustively expounded with a detailed analysis of the error existing inthe thermometric instrument. The practiced result shows that the apparatus is featured with asimple construction, high accuracy and high ability of anti-disturbance. It is proved to be ofpractical value.     

Cooperative Sensor Anomaly Detection Using Global Information

Sensor networks are deployed in many application areas nowadays ranging from environment monitoring, industrial monitoring, and agriculture monitoring to military battlefield sensing. The accuracy of sensor readings is without a doubt one of the most important measures to evaluate the quality of a sensor and its network. Therefore, this work is motivated to propose approaches that can detect and repair erroneous (i.e., dirty) data caused by inevitable system problems involving various hardware and software components of sensor networks. As information about a single event of interest in a sensor network is usually reflected in multiple measurement points, the inconsistency among multiple sensor measurements serves as an indicator for data quality problem. The focus of this paper is thus to study methods that can effectively detect and identify erroneous data among inconsistent observations based on the inherent structure of various sensor measurement series from a group of sensors. Particularly, we present three models to characterize the inherent data structures among sensor measurement traces and then apply these models individually to guide the error detection of a sensor network. First, we propose a multivariate Gaussian model which explores the correlated data changes of a group of sensors. Second, we present a Principal Component Analysis (PCA) model which captures the sparse geometric relationship among sensors in a network. The PCA model is motivated by the fact that not all sensor networks have clustered sensor deployment and clear data correlation structure. Further, if the sensor data show non-linear characteristic, a traditional PCA model can not capture the data attributes properly. Therefore, we propose a third model which utilizes kernel functions to map the original data into a high dimensional feature space and then apply PCA model on the mapped linearized data. All these three models serve the purpose of capturing the underlying phenomenon of a sensor network from its global view, and then guide the error detection to discover any anomaly observations. We conducted simulations for each of the proposed models, and evaluated the performance by deriving the Receiver Operating Characteristic (ROC) curves.     

超声探伤仪性能测试系统的研究与设计

为实现超声探伤仪性能测试自动化,提高测试效率和精度,研究并设计了一套超声探伤仪性能测试系统。系统以工控机作为中心处理单元,数据采集卡、超声波发射/接收卡实现了数据信号的采集和传输,通过GPIB总线来连接测试平台和待检仪器,简化了系统硬件组成。系统软件以Visual C++2008作为开发平台,采用模块化和结构化思想编写程序,具有良好的扩展性。采用小波分析方法对超声回波进行滤波,有效抑制了信号中噪声对测试精度的影响。试验结果表明,所开发的测试系统能够准确测试超声探伤仪器各项性能参数,实现了测试的智能化。     

木材入河设施钢滑道模型载荷测试系统

论述了钢滑道模型载荷测量原理，介绍了软件设计方法，其中包括传感器标定，风速风向监测，载荷测定，数据处理等程序。测试系统具有自动化程度高，测量精度高，软件优越，可靠性高等特点     

ARM电磁平衡传感器系统设计

采用高速精准的质量检测技术,是提高生产效率和自动化程度的有效途径之一。文中研究了基于ARM7单片机的电磁平衡传感器系统的工作原理和实现方法,包括系统的设计思想、设计原理、机械部分设计、电路硬件组成及软件流程。该系统实现了电磁平衡传感器的去初重、高精度及快速响应的功能。整个系统应用电磁力反馈平衡零位法原理,采用单片微处理器进行实时控制和数据处理,实现了质量检测的高速化、数字化、智能化,可以满足各种产品质量检测的需求。     

集成电路的计算机辅助测试

以9001测试系统为例，介绍计算机在集成电路测试技术中的应用及测试原理，以及现代测试中利用软件进行数据处理，提高测试精度的一些方法。     

加工中心在线检测系统的研究

针对离线测量的缺点，研究出加工中心在线检测系统。介绍硬件系统的组成、在线检测原理分析和软件系统的数据处理方法，设计平面度在线测量方法，并通过实测证明本测量系统可靠、经济、实用、准确度高，为工件测量提出了一种新的方法。     

基于Halcon的硒鼓缺陷检测与一维尺寸测量

为实现硒鼓表面缺陷检测和尺寸测量的自动化, 运用图像处理算法中的数学形态学算子对硒鼓表面点缺陷和线缺陷进行精确检测与分类, 并根据亚像素测量方法对硒鼓尺寸进行精确测量, 通过机器视觉专用软件Halcon和.NET开发了硒鼓缺陷自动检测与尺寸测量系统。测试结果表明, 该方法与应用像素级测量法相比, 其精度提高1~2个像素, 具有精度高、 稳定性强等优点。     

三坐标测量机测量误差的试验研究

操作不规范等诸多因素导致采用三坐标测量机测量的误差较大。为了探索操作方法、测球直径、测头进给方向与被测表面夹角和数据处理方法对测量精度的影响,设计了一种操作方法对测量精度影响的试验。该试验通过在两种测量模式下对高精度量块进行测量,研究了测头直径、测头进给方向与被测面之间的夹角对测量精度的影响。用MATLAB编程对测球中心点数据进行处理,与设备自带软件测量数据进行比较,研究了不同数据处理方法对测量误差的影响。分析了产生测量误差的原因,该研究对提高测量精度和研究数据处理方法有很好的参考价值。     

激光在易变形件尺寸测量中的应用

对于弹性件、薄壁件等易变形件尺寸的测量，常规的测量方法存在测量时间长、人为主观误差较大、自动化程度低等不足。本文以密封圈内、外径的测量为例，介绍用激光测量弹性件、薄壁件等易变形件尺寸的方法。根据夫朗和费单缝衍射测量原理，用数显容栅尺测量衍射条纹，用计算机进行数据处理，并用万能工具显微镜进行了对比测量。测量结果表明，激光法测量具有测量装置结构简单、测量结果精确度高、非接触和自动化测量等特点。     

线路参数自动检测系统数据的处理方法

给出一种非接触式铁路轨道线路参数检测系统的结构及功能,分析了各种线路参数的测量原理,并着重论述了用于检测线路方向和高低不平顺的弦测法和逆滤波原理及系统中采用的数据处理方法和逆滤波器实现技术.大量实验数据表明,该系统可靠性高,精度优于手工测量,完全满足铁路现场静态检测的要求.