Experiences with unexploded ordnance discrimination using magnetometry at a live-site in Montana

Advanced discrimination methods and careful optimization of operational procedures are critical for efficient remediation of unexploded ordnance (UXO) contaminated sites. In this paper, we report on our experiences with a 200 acre magnetic survey that was collected and processed under production survey conditions at Chevallier Ranch, Montana. All anomalies with fitted moments above 0.05 Am² were excavated. During the survey the magnetic remanence metric was predicted but not used to guide the discrimination. The retrospective analysis presented here reveals that discrimination using remanence would have significantly reduced the total number of anomalies (with good dipolar fits) that needed to be excavated, from 524 to 290 while still recovering all 69 UXO. The false alarm rate (FAR = number of non-UXOs excavated divided / number of UXO found) was reduced from 6.3 to 2.9. At a cut-off of 75% remanence, 77% of anomalies due to shrapnel and metallic debris and 64% of geological anomalies were rejected.Geological anomalies due to variations in magnetite concentration introduced a significant human-element into the interpretation process. Three different interpreters added a total of 305 additional anomalies that were not fit with a dipole model and which were later found to be non-UXO. Between 40 and 50% of anomalies picked by the two relatively inexperienced interpreters who analyzed the data turned out to be geology, as compared to 14% for an experienced interpreter. Critical analysis of results, operator training and feedback from the UXO technicians validating the anomaly are essential components towards improving the quality and consistency of the anomaly interpretations. This is consistent with the tenants of Total Quality Management (TQM). We compare the actual FAR that resulted during the survey when there was little feedback between UXO technician validation results, to a hypothetical result that could have been achieved had there been a constant feedback system in place at the onset of operations. Feedback would have significantly reduced the number of geological anomalies and decreased the FAR from 10.7 to 4.0.The hypothetical results presented here demonstrate the value of using TQM principles to guide the UXO remediation process. They further show that improvements in the efficiency and costs of UXO remediation require both technological advances and operational optimization of the technology when implemented in a production setting. Furthermore, by treating geophysical modeling and UXO validation as separate entities, both with respect to contracting and operational reporting, there is little incentive for the geophysicist to leave an anomaly off the dig-sheet. Only potential negative consequences will result if that anomaly is later found to be a UXO. An incentive based mechanism that rewards the geophysicist for reductions in follow-on costs would have a strong potential to reduce the number of unnecessary excavations, and hence reduce the total cost of the UXO remediation effort.     

南方海相地震资料脊波非线性阈值去噪方法

小波分析方法在数据处理中已得到成功广泛的应用,这主要得益于它的局部时频分析能力,但是小波分析对方向的表征能力有限。脊波变换具备优越的方向选择性能,能更好地处理含有线状变化特征的信号。本文针对低信噪比地震记录,尝试研究利用脊波变换方法对其进行处理,提高剖面资料信噪比,突出同相轴信息。在对南方某油田的实际地震资料的处理中,可以发现处理后的地震剖面同相轴品质及连续性有了明显改善,信噪比增强,分辨率相应提高,体现出了该方法相对常规小波分析方法的优越性。     

PRINCIPLES OF RIVER TRAINING AND MANAGEMENT

River regulation and river training have been performed for various purposes and negative effects have been shown in numerous cases. In some cases the negative effects are so serious that humans have to consider to "renaturalize" the regulated rivers. Only by using the strategy of integrated river management the diverse river uses and natural fluvial processes and ecological systems may be harmonized. Based on analysis of case studies and data collected from literatures this paper presents the concept of integrated river management and four principles of river training. The integrated river management comprises: 1) taking the watershed, upper stream basin including the tributaries, middle and lower reaches and the estuary as an integrated entity in the planning, design and management; and 2) mitigating or controlling the negative impacts on hydrology, erosion and sedimentation, fluvial processes, land use and river use, environment and ecology while in achieving economic benefit from water resources development, flood safety management and hydropower exploitation. River training and management should be in accordance with the four principles: 1) extending the duration of river water flowing on the continent, which may be achieved by extending the river course or reducing the flow velocity; 2) controlling various patterns of erosions and reducing the sediment transportation in the rivers; 3) increasing the diversity of habitat and enhancing the connectivity between the river and riparian waters; and 4) restoring natural landscapes.     

EFFECTS OF RIVER NETWORK WORKS AND SOIL CONSERVATION MEASURES ON RESERVOIR SILTATION

Knowledge of the morphological dynamics of a water course is essential for management of reservoir siltation. With an example of sedimentation in a reservoir in Basilicata, Italy, this paper demonstrates the effect on reservoir siltation of the hydraulic works, which are aimed to reduce sediment transport along the fluvial network and to prevent part of the sediment discharge from reaching the lake. The effect depends on the river type and on the the geological features of river basin slopes. The paper also shows how mass erosion can significantly contribute to development of reservoir siltation. Finally, preliminary results are provided about the time needed for river training works to be effective.     

山东省飞机增雨天气系统云水资源转化特征分析

利用水汽辐合法和水汽凝结法，对山东省1997－1999年春秋季18个降水过程的水汽辐合率、凝结率及降水效率等表征云水资源及其转化的特征量进行计算。分析了南方气旋、西北冷锋等主要降水天气系统以上特征量的地域分布和差别。可为人工增雨作业区域选择和航线设计提供气候背景。     

房产测绘管理系统软件开发中的若干问题

介绍了房产测绘管理系统开发过程中的几个关键的问题。分别对房产测绘管理系统的开发、运行环境、系统功能以及功能实现中的技术问题等进行了分析和探讨。     

遥感和GIS技术在全球海面风速分析中的应用

将遥感技术和地理信息系统（GIS）技术相结合，建立了一个基于TOPEX卫星的全球海面风速分析的海洋地理信息系统（MGIS）。阐述了全球海面风速分析模型的建立方法，定义了描述风场特征的相关参数，介绍了全球海面风速海洋地理信息系统的结构、功能和工作流程，另外，对系统的3个应用实例进行了地学分析。     

Rank-Defect Adjustment Model for Survey-Line Systematic Errors in Marine Survey Net

In this paper,the structure of systematic and random errors in marine survey net are discussed in detail and the adjustment method for observations of marine survey net is studied,in which the rank-defect haracteristic is discovered first up to now.On the basis of the survey-line systematic error model,the formulae of the rank-defect adjustment model are deduced according to modern adjustment theory.An examle of calculations with really observed data is carried out to demonstrate the efficiency of this adjustment model.Moreover,it is proved that the semi-systematic error correction method used at present in marine gravimetry in China is a special case of the adjustment model presented in this paper.     

周代军事测绘管理

系统的军事测绘管理始于周代，其影响深远。本文叙述了周代军事测绘管理的体制、职能及测绘管理队伍的构成，以期为继承中华文明的优秀成果提供借鉴。