局域网络故障检测技术方法     

韩燕义 《气象科技》2006,34(4):498-500

局域网络故障可分为常规故障和非常规故障。对常规故障应采用检查操作对象、分段检测、逐一排除、最终定位故障源的技术方法;非常规故障是一种既复杂又无规则的常见问题,对此种故障应采取屏幕提示、理论分析、经验判断等相结合的技术手段最终定位故障源。  相似文献   

Identifying environmental impacts of underground construction   总被引：2，自引：0，他引：2  

Premadasa M. Attanayake  Matthew K. Waterman 《Hydrogeology Journal》2006,14(7):1160-1170

Dewatering of the groundwater resource and associated reduced flow of surface water features are potential negative impacts when constructing underground facilities. Little work has been done to develop methods for the early detection of environmental impacts on water resources where major underground construction is being undertaken. Recognizing this, prior to construction of two rock tunnels in the southwestern USA, a 3-year preconstruction program was implemented to monitor over 100 wells, springs, and streams in the project area that might be affected. This preconstruction monitoring phase has established data for a hydrologic reference which indicates a high degree of spatial and temporal variability. This variability must be accounted for when trying to identify construction-related impacts. The project area was subdivided into areas of similar characteristics based on geologic and hydrologic features. Measurements from features within each unit were then normalized and aggregated to derive a single representative flow parameter. This representative flow was then correlated to precipitation and major stream flow records to allow for a method of estimating unimpacted flow and groundwater levels during and after construction. Application of this method proved useful in determining and enabling a quick response to construction-related impacts.  相似文献   

基于灰度形态学的高分辨率遥感图像边缘检测研究   总被引：2，自引：0，他引：2  

王芳  夏丽华 《测绘与空间地理信息》2006,29(2):23-25

提出一种用于高分辨率遥感图像边缘检测的灰度形态学方法,该算法在数学形态学的基础上,针对图像中噪声和边缘形态的不同建立了多结构元素,利用灰度形态变换原理的膨胀、腐蚀、开启和闭合等算法进行边缘提取。实验表明,与经典的边缘检测算子相比,该算法保持图像的细节特征,较好地解决边缘检测精度与抗噪声性能的协调问题,具有很好的边缘提取能力。本文给出了用Matlab6.5实现的具体代码。  相似文献   

关于变电站雷电防护应注意的问题     

胡泉  覃春霞 《广西气象》2006,27(2):43-45

根据变电站受雷害的特点，提出了变电站在防直击雷保护和防沿线路过电压保护应该注意的一些问题。并着重对变电站中的重要设备的防雷保护进行了介绍。  相似文献   

Spatial distribution of rainfall trends in Sicily (1921-2000)   总被引：7，自引：0，他引：7  

M. Cannarozzo  L.V. Noto 《Physics and Chemistry of the Earth》2006,31(18):1201-1211

The feared global climate change could have important effects on various environmental variables including rainfall in many countries around the world. Changes in precipitation regime directly affect water resources management, agriculture, hydrology and ecosystems. For this reason it is important to investigate the changes in the spatial and temporal rainfall pattern in order to improve water management strategies.In this study a non-parametric statistical method (Mann-Kendall rank correlation method) is employed in order to verify the existence of trend in annual, seasonal and monthly rainfall and the distribution of the rainfall during the year. This test is applied to about 250 rain gauge stations in Sicily (Italy) after a series of procedures finalized to the estimation of missing records and to the verification of data consistency.In order to understand the regional pattern of precipitation in Sicily, the detected trends are spatially interpolated using spatial analysis techniques in a GIS environment.The results show the existence of a generalized negative trend for the entire region.  相似文献   

利用施工断面进行地下管线普查     

于雷 《测绘与空间地理信息》2006,29(5):115-116

提出利用市政工程施工开挖的断面,对暴露陈旧的地下管线进行GPS测量,取得管线的3维坐标,建设地下管线动态管理地理信息系统的探讨。  相似文献   

基于整体变分模型的影像阴影检测算法研究     

王树根  王军利  王爱萍 《武汉大学学报(信息科学版)》2006,31(8):663-666

将影像上普遍存在的阴影视为图像退化的一种特殊形式，以整体变分模型为基础，以影像上阴影区域亮度普遍较暗且较均匀、阴影区域和非阴影区域之间的反差普遍较大的特点为约束，导出了整体变分模型用于影像上阴影检测的基本算法。通过对若干幅实际影像的阴影检测实验表明，本文算法对灰度影像和彩色影像上阴影区域的检测是有效的。  相似文献   

地下全空间瞬变电磁技术在煤矿巷道掘进头的连续跟踪超前探测   总被引：15，自引：1，他引：15       下载免费PDF全文

郭纯  刘白宙  白登海 《地震地质》2006,28(3):456-462

文中介绍了利用地下全空间瞬变电磁(UWTEM)技术在某煤矿-250排水巷道掘进过程中进行的连续跟踪超前探测试验。根据初探结果,采用不共面同轴偶极观测方式时,UWTEM在巷道掘进头前方的有效探测范围约为70m,巷道每掘进50m进行一次跟踪探测。试验表明,利用该技术可以有效地超前预测煤矿巷道掘进头前方30~50m范围的富水异常,为及时采取水害治理措施提供依据  相似文献   

用于检测同相轴的Duffing型系统恢复力项的讨论          下载免费PDF全文

赵雪平  李月  杨宝俊 《地球物理学进展》2006,21(1):61-69

在用于检测同相轴的Duffing型系统中,非线性恢复力项的选取至关重要.针对具有不同非线性恢复力项的混沌系统,本文首先就非线性恢复力项的来源进行了说明,通过对哈密顿系统和耗散系统的仿真实验分析,以及理论推导,确定了势能—哈密顿多项式方程中可用于混沌振子检测系统的各项幂次和各项系数组合关系,即非线性恢复力项的选取规则:幂次最高项为奇次,其系数大于零.  相似文献   

基于摄动有限元方法对梁结构损伤的识别   总被引：1，自引：0，他引：1  

杜思义  殷学纲  张卫民  陈淮 《世界地震工程》2006,22(2):114-118

结构损伤的定量识别是工程技术中急待解决的问题。利用矩阵摄动和结构有限元动力学理论推出梁结构损伤程度定量识别的公式和方法,该方法仅需要在役结构的固有频率测量值就可识别结构的损伤位置和损伤程度,而且可以识别结构的老化程度,避免了由模态振型识别损伤,因测量自由度不足带来的误差,通过对一钢悬臂梁损伤识别的数值仿真,证明了该方法的有效性。该方法具有较大的工程应用价值。  相似文献