利用宽带测向数据实现多用户共享监测

本文创新地提出利用宽带测向数据的清洗、处理、共享和分析的方法,实现B/S架构无线电监测系统中多用户共享测向资源,提升测向设备使用效率和用户工作效率,解决系统中多用户抢占测向资源的业内难题。

基于航空ZC测向数据聚类检测

针对航空ZC测向线分布密集,数量较多,不易区分辐射源的问题,文章首先基于高斯核的局部密度聚类中心估计算法进行决策判断,得到初始聚类中心,再基于K-means聚类检测对测向线进行分选。仿真结果表明,在辐射源距离较近和测向线众多的情况下,该方法仍可基于测向数据准确地对目标进行聚类,具有一定的可行性。

构建干涉仪测向系统的数据评估体系

基于中短波干涉仪测向系统和我台自主开发的测向软件,通过深入分析和挖掘测向数据、监测信号指标数据,实现了监测和测向系统的实时互动,解决了测试数据不足的问题。通过对测向数据示向度中值、离散度、变化率和置信度等参数的研究,初步形成了完整的测向结果科学评估体系,实现了测试数据事后综合分析,可对获取的数据进行多方位的深入分析,提高测向数据的可信度。

无线电测向系统开场测试测向精度的测试数据异常值判别方法

通过分析四种常用异常值判别准则,找到适合用于剔除无线电测向系统开场测试测向精度的测试数据异常值的判别方法,从而保证测试数据的有效性。通过计算结果可知,样本数小于100时,建议采用肖维勒准则;样本数大于100时,建议采用莱依达准则;但当剔除异常值比例超过10%时,建议采用格拉布斯准则(置信概率为95%)。

基于Gauss坐标系的测向误差统计模型分析

由GPS测量的经纬度计算目标方位,是统计测向误差的重要内容,采用的坐标系不同,带来的统计误差不同。介绍了基于Gauss平面投影坐标系的计算方法,模型清晰,方位角度计算方便,适用于测向误差的统计。给出了计算模型,对由中央经线取值产生的误差进行了仿真分析,并介绍了消除统计误差的简单方法.

短波定位数据描述方法的研究

本文从现有的测向定位工作方式和上报数据格式入手,在对ITU及现有监测规范进行调研的基础上,提炼测向数据的描述及评价方法,内容涵盖信号的发射状态、监测设备设置和监测结果,重点设计了短波定位效果评级方法。

海上编队无源定位技术及工程实现

探讨基于测向交叉定位的海上编队无源定位技术及工程实现 .主要从系统组成及定位流程、定位相关、测向数据校准处理。

APPLICATION OF GREY SYSTEM THEORY TO PROCESSING OF MEASURING DATA IN REVERSE ENGINEERING

The processing of measuri ng data plays an important role in reverse engineering. Based on grey system the ory, we first propose some methods to the processing of measuring data in revers e engineering. The measured data usually have some abnormalities. When the abnor mal data are eliminated by filtering, blanks are created. The grey generation an d GM(1,1) are used to create new data for these blanks. For the uneven data sequ en ce created by measuring error, the mean generation is used to smooth it and then the stepwise and smooth generations are used to improve the data sequence.

短波非平稳色散信道中的方位角估计精度改善算法

针对短波宽带测向数据检测、分段后信号的方位角估计问题，提出了一种基于测向结果信息加权的方位角估计精度改善算法，利用测向结果中的能量和信号质量信息，对相应时频点的方位角值进行加权估计，提高方位角估计精度，实际数据验证表明算法的方位角估计精度达到0．5度。

Life prediction of ZPW-2000A track circuit equipment based on SVDD and gray prediction

Evaluation of the health state and prediction of the remaining life of the track circuit are important for the safe operation of the equipment of railway signal system.Based on support vector data description(SVDD)and gray prediction,this paper illustrates a method of life prediction for ZPW-2000A track circuit,which combines entropy weight method,SVDD,Mahalanobis distance and negative conversion function to set up a health state assessment model.The model transforms multiple factors affecting the health state into a health index named H to reflect the health state of the equipment.According to H,the life prediction model of ZPW-2000A track circuit equipment is established by means of gray prediction so as to predict the trend of health state of the equipment.The certification of the example shows that the method can visually reflect the health state and effectively predict the remaining life of the equipment.It also provides a theoretical basis to further improve the maintenance and management for ZPW-2000A track circuit.

Pattern recognition and prediction study of rock burst based on neural network

Many monitoring measures were used in the production field for predicting rockburst.However, predicting rock burst according to complicated observation data is alwaysa pressing problem in this research field.Though the critical value method gets extensiveapplication in practice, it stresses only on the superficial change of data and overlooks alot of features of rock burst and useful information that is concealed and hidden in the observationtime series.Pattern recognition extracts the feature value of time domain, frequencydomain and wavelet domain in observation time series to form Multi-Feature vectors,using Euclidean distance measure as the separable criterion between the same typeand different type to compress and transform feature vectors.It applies neural network asa tool to recognize the danger of rock burst, and uses feature vectors being compressedto carry out training and studying.It is proved by test samples that predicting precisionshould be prior to such traditional predicting methods as pattern recognition and critical indicatormethod.

Hierarchical Detailed Description for Spatial Direction Relations

Direction relation is an important spatial relation. Descriptions and representations for direction relations have different levels of detail because of the varying dimensions of spatial objects and different scales of the embedding spaces. Based on a direction- relation matrix, the hierarchical frame of spatial direction relations which partitions direction relations orderly and thoroughly is built. Interior direction relations are used to perfect the representation of direction relations and the binary-encoding idea is creatively applied to construct an interior detailed matrix describing multiple interior direction relations by a uniform matrix. The model integrates topological information into the description model for direction relations, which will lay the foundations of spatial compositive reasoning.

A Non-geometrically Similar Model for Predicting the Wake Field of Full-scale Ships

The scale effect leads to large discrepancies between the wake fields of model-scale and actual ships, and causes differences in cavitation performance and exciting forces tests in predicting the performance of actual ships. Therefore, when test data from ship models are directly applied to predict the performance of actual ships, test results must be subjected to empirical corrections. This study proposes a method for the reverse design of the hull model. Compared to a geometrically similar hull model, the wake field generated by the modified model is closer to that of an actual ship. A non-geometrically similar model of a Korean Research Institute of Ship and Ocean Engineering （KRISO）’s container ship （KCS） was designed. Numerical simulations were performed using this model, and its results were compared with full-scale calculation results. The deformation method of getting the wake field of full-scale ships by the non-geometrically similar model is applied to the KCS successfully.

Choice of reference surfaces for machined surface roughness in milling of SiC_p/Al composites

In order to choose the appropriate reference surface on the machined surface roughness of Si Cp/Al composites, the cutting experiments of Si Cp/Al composites were carried out, and the machined surface topography was measured by OLS3000 Confocal laser scanning microscope. The 3D measured data of machined surface topography were analyzed by the area power spectrum density. The result shows that the texture of machined surface topography in milling of Si Cp/Al composites is almost isotropic. This is the reason that the values of Rq at different locations on the same machined surface are obviously different. Through the comparison of performance of different filtering methods, the robust least squares reference surface can be used to extract the surface roughness of SiC p/Al composites effectively.

Optimization of support vector machine power load forecasting model based on data mining and Lyapunov exponents

According to the chaotic and non-linear characters of power load data,the time series matrix is established with the theory of phase-space reconstruction,and then Lyapunov exponents with chaotic time series are computed to determine the time delay and the embedding dimension.Due to different features of the data,data mining algorithm is conducted to classify the data into different groups.Redundant information is eliminated by the advantage of data mining technology,and the historical loads that have highly similar features with the forecasting day are searched by the system.As a result,the training data can be decreased and the computing speed can also be improved when constructing support vector machine(SVM) model.Then,SVM algorithm is used to predict power load with parameters that get in pretreatment.In order to prove the effectiveness of the new model,the calculation with data mining SVM algorithm is compared with that of single SVM and back propagation network.It can be seen that the new DSVM algorithm effectively improves the forecast accuracy by 0.75%,1.10% and 1.73% compared with SVM for two random dimensions of 11-dimension,14-dimension and BP network,respectively.This indicates that the DSVM gains perfect improvement effect in the short-term power load forecasting.

Multi-beam Sonar and Side-scan Sonar Image Co-registering and Fusing

Multi-beam Sonar and Side-scan Sonar compensate each other. In order to fully utilize all information, it is necessary to fuse two kinds of image and data. And the image co-registration is an important and complicated job before fusion. This paper suggests combining bathymetric data with intensity image, obtaining the characteristic points through the minimal angles of lines, and then deciding the corresponding image points by the maximal correlate coefficient in searching space. Finally, the second order polynomial is applied to the deformation model. After the images have been co-registered, Wavelet is used to fuse the images. It is shown that this algorithm can be used in the flat seafloor or the isotropic seabed. Verification is made in the paper with the observed data.

An Appropriate Unidirectional Wave Spectrum Model for the Strait of Hormuz

The objective of this paper is to introduce an appropriate unidirectional wave spectrum model for the Strait of Hormuz. The research is focused on assessing performance of standard wave spectrum models in the region. By evaluating such models based on valuable measurement data recently published, the calibration procedure has been conducted on such standard models to reach a better concordance between a modified standard spectral model and observed field spectra. The calibration is performed initially with respect to four distinct directions related to four available measurement stations. So, it results in four sets of coefficients for a nominated model. Next, it is continued to reach just one model insensitive to directions. Results clearly showed that the International Towing Tank Conference （ITTC） model is more appropriate than Joint North Sea Wave Project （JONSWAP） and Pierson and Moskowitz （PM） models in this area, even without any calibration. However, modifications have been successful on improving the conformity of the model.

Influence of stress anisotropy on the cylindrical cavity expansion in undrained elastic-perfectly plastic soil

This work presents an analysis of the influence of stress anisotropy on cylindrical cavity expansions in an undrained elastic-perfectly plastic soil. This problem was formulated by assuming a large strain in both the elastic and plastic zones around the cavity and a plain strain condition during the cavity expansion process. The solutions for the limit pressure, stress, and excess pore pressure were obtained by introducing the anisotropic initial stress coefficient K_0 into the conventional cylindrical cavity expansion method.The proposed solutions were then used to interpret the piezocone penetration test, and the suitability of the solutions was verified by comparing the prediction with the piezocone penetration test data. Subsequently, parametric studies were carried out to investigate the influence of stress anisotropy on the stress, excess pores pressure distributions around an expanding cylindrical cavity, and limit pressure. The results show that the proposed cylindrical cavity expansion method under stress anisotropy is suitable and can be used to investigate the piezocone cone test. The present work improves upon the conventional theoretical framework of cavity expansion and can be applied to the determination of the stresses around axially loaded piles and around in-situ testing devices such as penetrometers.

Method study and uncertainty analysis of calibration coefficients validation based on the Inner Mongolia test site

Calibration coefficients validation is the foundation for ascertaining the sensor performance and carrying out the quantitative application.Based on the analysis of the differences between the calibration and validation,two calibration coefficients validation methods were introduced in this paper.Taking the HJ-1A satellite CCD1 camera as an example,the uncertainties of calibration coefficients validation were analyzed.The calibration coefficients validation errors were simulated based on the measured data at an Inner Mongolia test site.The result showed that in the large view angle,the ground directional reflectance variation and the atmospheric path variation were the main error sources in calibration coefficients validation.The ground directional reflectance correction and atmospheric observation angle normalization should be carried out to improve the validation accuracy of calibration coefficients.