【作者】 夏美威(Nchimunya Chaamwe)；

【导师】 刘文予； 蒋洪波；

【作者基本信息】 华中科技大学 ， 通信与信息系统， 2011， 博士

【摘要】 随着外商投资的扩大,赞比亚地下矿山的不断被开发及商业化。这直接导致了矿工工作环境的恶化。为了改善他们的工作环境,在采矿行业建立更加严格的监管及评估标准势在必行。学术界的专家们,政府官员们和私营企业主越来越关注这个问题,并把矿井环境的改善及其危害的减轻当作首要目标。经过通力合作后,矿井的通风设备及安全条件等已取得极大的进步,但是,矿难的步伐并没有因此停下,尤其是在赞比亚。因此,在监督方面的更高的计划要求及行动迫在眉睫。本文探索了无线传感网络(WSNs)在地下矿山环境监测中应用的可能性。本文的目标是利用新兴科技解决全球范围内的共同问题—矿工工作环境的恶化。本文所提供的所有观点已经经过可行性及特征验证,并针对矿井环境改善而研究了低功率无线网络科技。正如本段开头所述,无线传感器网络作为一个新兴现代地下环境监测工具,有着无可比拟的优越性。它流动性强,灵活性高,易测量,易安装,在紧急事件如矿山爆炸或塌陷的时候能被快速展开运作。而且,它的自我修复,自我组织,多路径传播和监测度高等特性使它成为解决地下或密闭空间的高度安全性及紧急事件的能手。本文深刻阐述了无线传感器网络在地下矿山环境监测方面的巧妙运用,希望通过这些研究能帮助解决世界的又一难题。本文的第一部分是关于之前进行的一次实地考察的分析及讨论。为了评估赞比亚目前地下矿山的环境监测方法,本文挑选出赞比亚铜带省6家矿产企业作为调查对象。研究结果表明赞比亚矿产企业都是利用人工监测或有线传感器去监测地下环境,而且由于这些方法的有效性极低,在过去五年内矿难经常发生。而且进一步的调查显示,其中4家企业的安全及环境部门非常乐意接受无线传感器网络的使用以便改善地下矿井环境。本文的第二部分是寻求如何在地下环境中建立电波的传播模型。由于地下环境特性的限制,很难将无线传感器网络充分应用及扩展。经过对地下环境的无线传播特性调查后(包括现有传播模型的检查及其限制的确定),本文设计了两种模型。第一种是将传感器埋在地下,这需充分考虑到土壤及岩石对电波传播的影响。第二种是将传感器放置在开放空间里,如矿井通道等,这需要考虑到波的衍射,如在地下通道的穿梭矿车有可能会影响正在传播的波。更多还原

【Abstract】 Zambian underground mines are becoming more mechanized and extensive with the coming in of foreign investors, this has in turn resulted in the deterioration of the working environment for the miners. In order to improve the underground mine working environment, more stringent monitoring and assessment standards need to be designed, formulated and applied to the mining industry. The main goal of some professionals in academic circles, the government and the private sector has been to bring improvement in the underground mine environment and mitigate its hazards. As a result of their efforts, there has been tremendous professional progress and improvement in the area of mine ventilation and safety. It is however unfortunate that mine disasters have continued to occur throughout the world and Zambia in particular. It is for this reason that, a need has been felt for further advances in plans and designs for monitoring underground mine environments.In this thesis we explore the potential of wireless sensor networks (WSNs) in the context of underground mine environmental monitoring. Our goal is to confront an emerging technology with a concrete problem of world-wide dimensions, the safety of miners working in hostile underground environments. The work presented in this thesis has investigated the feasibility, characteristics and potential applications of low power wireless networking technology, particularly aimed at improving underground mine safety. Following an initial review, wireless sensor networks (WSNs) were identified as having many desirable attributes as a modern underground environmental monitoring tool. WSNs are mobile, flexible, and easily scalable, installation time is reduced and there is scope for rapid deployment in case of an emergence such as a mine explosion or roof rock fall. The self-healing, self-organizing, multiple pathway redundancy, and highly scalable nature of WSNs are particularly advantageous for underground, or confined space, high-integrity safety and emergency applications. The study and potential use of WSNs in an underground mine is a novel aspect of this thesis.In the first part of the thesis we present and discuss the results of a field survey we carried out, whose aim was to assess the current underground mine environmental monitoring methods in Zambia. The research covered 6 mining companies on the Copperbelt province of Zambia. Our study revealed that the mines in Zambia, uses manual monitoring methods or wired sensors to monitor environmental conditions underground. The study also revealed that the current methods are not very effective and a number of accidents that could have been avoided were recorded in the past five years. The safety departments and the environmental departments which were our targeted respondents in all the 4 out of the 6 mines that participated unanimously welcomed the idea of introducing WSNs as monitoring tools for environmental conditions in underground mines. We then presented a WSN for underground mine environmental monitoring framework and discussed the challenges of implementing such a framework.The second part of the thesis is devoted to wave propagation modeling in underground environments. The nature of the underground environment makes it difficult for the Wireless underground Sensor networks applications to be fully implemented and appreciated. We investigated wireless propagation characteristics in underground environments and this involved examining existing propagation models and identifying their limitations. We then designed two models, the first one concerns sensors that are buried underground. Our proposed model takes into account most of the soil or rock properties that affects wave propagation. The second model concerns sensors that are underground but in open spaces such as mine tunnels. Our proposed model revealed that wave diffraction due to the obstacles such as shuttle cars in underground mines have an effect on the propagated wave.更多还原