探地雷达回波信号预处理方法浅析

探地雷达是近年来被广泛应用于各个工程领域的高精度无损探测技术.本文主要介绍了探地雷达回波信号预处理的方法,这些方法可有效地消除回波噪声并校正反射时差,使回波剖面清晰、直观地呈现出被测物体.     

智能化综放工作面顶煤厚度探测方法

提前探测综放工作面顶煤厚度可为精准控制放顶煤提供依据,有利于实现放煤采出率和煤质的平衡。通过分析探地雷达探测煤岩界面及煤层厚度的原理,设计了一种用于探测顶煤厚度的探地雷达装置,进一步提出了基于探地雷达的智能化综放工作面顶煤厚度探测方法:通过探地雷达装置发射和接收雷达脉冲波,接收信号经放大、采样、积分等处理形成雷达帧,通过WiFi方式实时传输至无人采煤机控制单元,最终传输至集控室控制台,由煤岩分界面提取软件处理、分析反射信号波形与灰度图,根据反射信号最大幅值与最小幅值确定煤岩分界面位置,通过最大或最小幅值位置与雷达脉冲发射起点的时间差计算出煤层厚度。在王家岭煤矿12309综放工作面对该方法进行测试,结果表明:某处雷达反射波灰度图解释的顶煤厚度探测结果为3.383m,与人工测量的实际值(3.16m)误差为7%;可探测最大顶煤厚度为5m,最大探测误差不超过10%,满足实际探测需求。     

探地雷达测定土壤含水率研究综述

准确快速测定土壤含水率,在理论研究与实际应用中都具有重要意义.在综合分析烘干法、中子法、时域反射法和遥感4种土壤含水率测定方法的优缺点基础上,指出探地雷达是一种适合于中尺度的土壤含水率测定的技术.对探地雷达以及探地雷达测定土壤含水率的技术原理与方法进行全面介绍,并以介电常数与土壤含水率的关系模型为主,对国内外这方面的研究工作以及存在的问题进行了总结.最后指出,探地雷达测定土壤含水率是一项非常有前景的技术,但目前国内在这方面的研究工作与国外相比远远不够,今后应加强这方面的研究工作.     

基于探地雷达的煤岩界面探测数据解释方法

针对现有煤岩界面识别方法缺乏对煤岩层特性的研究、无法对数据进行较好解释的问题,结合基于探地雷达的煤岩界面探测模型,提出了一种煤岩界面探测数据解释方法,即采用一种改进的最大类间方差法,在二维灰度直方图下对探地雷达探测的煤岩图像进行阈值化分割,从而实现煤岩界面识别。通过仿真实验研究了探地雷达天线频率对可探测煤层厚度的影响,结果表明随着天线频率增大,理论可探测最大煤层厚度减小;采用LTD-2100型探地雷达,设置400 MHz天线频率进行现场测试,结果表明基于探地雷达的煤岩界面探测数据解释方法可提高煤岩界面识别准确性。     

偏移技术在探地雷达数据处理中的应用

探地雷达是近年来快速发展的高精度无损探测技术,被广泛应用于各个工程领域.但往往由于地下介质分布复杂使得回波剖面包含有大量的绕射波及各种干扰波,严重影响被测物的识别甚至掩盖了被测物体.本文主要介绍了探地雷达回波信号处理中的几何偏移和绕射叠加偏移,可用来有效地消除噪声及绕射干扰,使回波剖面清晰、直观的呈现出被测物体.     

一种简化的雷达三维探测数据生成方法研究

雷达电子战三维实时视景仿真能够全面表现雷达电子战系统的作战态势、进程和对抗效果,为指挥员正确把握战场态势提供支持。在进行雷达电子战三维视景仿真时,传统的方法是直接构建雷达的三维探测数据,然后生成三维态势图。传统方法导致计算复杂,数据量大,不能够满足实时仿真的要求。现提出了一种在雷达探测范围二维包络线计算模型的基础上,结合垂直面上雷达天线方向图,空间数据生成的简化算法,同时考虑了雷达受到干扰情况下雷达天线垂直方向函数的修正方法。以上方法简化了计算过程,有效的减少了数据量。利用提出的方法,开发的视景仿真系统在实践中得到了应用,能够满足实时要求,文中给出了具体实例和仿真结果图。     

地基与机载气象雷达探测数据转换算法研究

利用地基多普勒气象雷达探测数据恢复出真实气象目标的位置、移动速度、范围大小,通过对地基气象雷达数据进行空间插值处理,设计仿真算法,在机载雷达扫描方向上进行空间分层投影和插值,在不考虑旁瓣回波和载机实际飞行状态等因素的影响时,得到理想的扫描模型,完成机载多普勒气象雷达对相应区域的扫描产品的仿真.实验表明仿真回波适用于分析机载雷达探测云雨的回波特性.     

复杂地形环境下雷达效能仿真并行算法设计

研究雷达效能优化问题,针对确定雷达的有效探测覆盖范围,确定目标的可测性,在复杂地形环境下雷达覆盖范围的计算是一个计算量较大的问题,必须考虑可能覆盖区域中每一点所处的地形地貌特征,以确定目标在位置的可探测性.为了提高仿真计算效率,分析了并行方式进行雷达覆盖范围基本原理,提出了一种雷达覆盖范围仿真方法,并利用MPI平台进行了仿真.仿真结果表明,方法可有效提高复杂地形环境下雷达效能仿真计算的效率,可以实现大场景和复杂地形条件下的雷达效能仿真,并提供了高效实现方法与途径.     

基于超宽带源的FDTD正演模拟及偏移处理

本文推导了以CPML作为吸收边界条件的FDTD迭代公式,并以超宽带雷克子波作为发射源,模拟得到了二维正演剖面;采用相位移偏移方法对正演剖面进行了处理,提高了正演剖面的分辨率.正演模拟与偏移处理的结合,为今后利用超宽带探地雷达进行地下目标探测及识别打下了良好的理论基础.     

基于经验模态分解的探地雷达信号去噪处理

探地雷达作为一种先进的地球物理探测方法,具有探测效率高、操作简单、采样迅速、无损伤探测、探测分辨率高等优点。探地雷达的信号的去噪问题已成为一个公认的技术难题。本文用经验模态分解的方法对探地雷达信号进行信号去噪处理,并取得了良好的效果。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate