A neural network approach for the real-time detection of faults   总被引：2，自引：2，他引：0  

Yahya Chetouani 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(3):339-349

Fault detection is an essential part of the operation of any chemical plant. Early detection of faults is important in chemical industry since a lot of damage and loss can result before a fault present in the system is detected. Even though fault detection algorithms are designed and implemented for quickly detecting incidents, most these algorithms do not have an optimal property in terms of detection delay with respect to false alarm rate. Based on the optimization property of cumulative sum (CUSUM), a real-time system for detecting changes in dynamic systems is designed in this paper. This work is motivated by combining two fault detection (FD) strategies; a simplified procedure of the incident detection problem is formulated by using both the artificial neural networks (ANN) and the CUSUM statistical test (Page–Hinkley test). The design of a model-based residual generator is intended to reveal any drift from the normal behavior of the process. In order to obtain a reliable model for the normal process dynamics, the neural black-box modeling by means of a nonlinear auto-regressive with eXogenous input (NARX) model has been chosen in this study. This paper also shows the choice and the performance of the neural network in the training and test phases. After describing the system architecture and the proposed methodology of the fault detection, we present a realistic application in order to show the technique’s potential. The purpose is to develop and test the fault detection method on a real incident data, to detect the change presence, and pinpoint the moment it occurred. The experimental results demonstrate the robustness of the FD method.  相似文献   

Analysis on the Seismic Response of Soil Slopes Based on the Multi-point Input Method   总被引：1，自引：1，他引：0  

Li Li  Jing Pengxu  Xu Qin 《中国地震研究》2017,31(4):574-588

In general, the seismic response analysis in earthquake engineering assumes that the vibration parameters of the target and the contact surface of the external media are identical, i. e., single point input. However, earthquake energy has an attenuation phenomenon in wave propagation, so a wide range of soil slopes and the external medium contact surface of different input points on motion are not identical. If we consider single point input only, it may not correspond with reality, so it is necessary to carry out research on multi-point input methods. Based on the 2-D slope model, single-point input and multi-point input are performed respectively to analyze and compare their similarities and differences in the perspectives of the characteristics of seismic response of soil layer and plastic zone distribution to provide a reference for the seismic design of slopes. The results show that in the perspective of soil seismic response analysis, the peak acceleration output and peak velocity output under multi-point input are greater than the peak values under single point input at the same monitoring point, the peak appearing time is also earlier than that of the single point input; in terms of the plastic zone distribution, the multi-point effect is manifested as the presence of more obvious tensile shear failures; in the perspective of safety coefficient, the safety coefficient under each multi-point input is smaller than that of single point input, a difference of about 7% or so. In summary, multi-point input is more reasonable and practical than single point input, so multi-point input should be considered in seismic design.  相似文献   

基于暗原色先验的遥感影像去雾方法研究     

郑新杰  肖一鸣  巩翼龙 《测绘与空间地理信息》2020,(1):57-60

目前,遥感影像应用的场景越来越多,但受到空气污染或气候等原因影响,局部地区雾霾现象严重,严重影响遥感影像质量。针对这一问题,本文结合遥感影像的特点提出了一种基于暗原色先验的遥感影像去雾方法。首先,结合遥感影像的特点,在求取暗通道过程中设置失效点,排除不符合暗原色先验的像素点;其次,根据获得的暗通道计算大气光值;然后,求取透射率图并用导向滤波精细化,根据大气传输模型求得去雾后的影像;最后,分别用无人机影像和Landsat卫星遥感影像进行去雾实验,验证了本文方法的有效性。  相似文献   

基于内容分析法的喀斯特洞穴导游解说词研究   总被引：2，自引：2，他引：0  

杨晓霞  石定芳  向旭 《中国岩溶》2013,32(2):239-246

导游解说词不仅有助于游客对喀斯特洞穴景观的观赏,而且能增长游客的科学知识,有利于洞穴景观和环境的保护.本文选取了具有代表性的22个国内喀斯特洞穴导游解说词作为研究样本,设计出23项分析指标,分别统计各指标在研究样本中的频次和频率,最后获得频率超过50％的共性指标14个.通过分析得出以下结论:(1)我国喀斯特洞穴导游解说词目前处于“百花齐放”阶段,共性大于个性;(2)我国喀斯特洞穴导游解说词的内容框架已基本形成,主要包括欢迎词、洞穴概况、景点讲解、欢送词4部分;(3)我国喀斯特洞穴导游解说词在内容上与国外开发成熟的洞穴相比还存在较大差距,国内喀斯特洞穴的导游词关注科学知识较少,神话传说的比重过大.  相似文献   

黑龙江呼玛旁开门金银矿矿带地质特征与找矿标志   总被引：2，自引：0，他引：2  

胡忠贤  崔永生  曲瑞增  解丽花 《世界地质》2013,32(4):763-772

旁开门金银矿床位于黑龙江省呼玛县境内,目前已发现 5 个矿带 11 个矿体。其中Ⅱ、Ⅲ、Ⅴ 矿带 5 个矿体已完成了详查工作,矿体呈不规则脉状,沿走向和倾向有膨胀和收缩现象,受一组北北西向张性断裂控制。矿体主要赋存于下白垩统龙江组安山岩破碎带中,空间分布与硅化角砾岩一致,载矿岩石主要为硅化角砾岩。金平均品位 2. 77 × 10 －6,银平均品位 60. 58 × 10 －6,探求 332 + 333 金、银资源量分别为 8. 70 t、138. 31 t,为一中型金银矿。通过对旁开门金银矿的地质特征分析,认为该矿体受下白垩统龙江组、光华组及北北西向断裂控制,属中低温火山热液型矿床。围岩蚀变 ( 硅化、绢云母化、破碎化、黄铁矿化) 及物化探异常等找矿标志对省内寻找同类矿床具重要意义。  相似文献   

基于北斗系统的LBS在景区智能导游系统中的应用     

崔煜  张京宁 《测绘与空间地理信息》2013,36(6):98-101

旅游业已经成为我国国民经济的重要支柱,但是各景区普遍存在服务能力有限、方法欠佳等问题,导致游客满意度不高,投诉事件屡见不鲜,景区管理难度较大。LBS是近年来国内外在导航应用领域中的一个热点,应用比较广泛。本文介绍了基于北斗的LBS的功能及应用前景,并在此基础上,研究了景区智能导游系统,分析了系统结构和工作模式,给出了系统建设方案,探讨了该系统在景区管理中的作用。  相似文献   

Effect of rock mass disturbance on the stability of rock slopes using the Hoek–Brown failure criterion     

A.J. Li  R.S. Merifield  A.V. Lyamin 《Computers and Geotechnics》2011

The process of creating man made or “cut” slopes in rock invariably leads to stress relief within the rock mass which in turn induces a certain degree of fracturing and disturbance. The level of disturbance can be particularly significant when the slope is formed using blasting techniques. However, the effects of this disturbance on the overall rock slope stability have not been investigated thoroughly in the current literature. In order to account for rock mass disturbance during construction, a disturbance factor has been included in the Hoek–Brown failure criterion [1]. This paper uses finite element upper and lower bound limit analyses to estimate rock slope stability based on the Hoek–Brown failure criterion whilst including the effect of rock mass disturbance. A rigorous set of analyses have been performed where the level of disturbance is considered as constant or linearly varying throughout the slope. The results are then compared to a number of reported case histories for verification purposes. From the results of this study, the disturbance factor was found to have significant influence on the rock slope stability assessment, especially for poorer quality rock masses. Hence, cautious engineering judgement must be exercised when estimating the level of disturbance. In addition, utilising stability charts to estimate the stability of cut rock slopes without considering the rock mass disturbance may lead to significant overestimations.  相似文献   

重力式导向防斜钻具在钻孔灌注桩施工中的应用及探讨          下载免费PDF全文

廖光华 《探矿工程》2011,38(1):63-65

介绍了一种高垂直度要求钻孔灌注桩施工的防斜钻具——重力式导向防斜钻具的设计、加工,及其在福州至银川高速公路九江长江公路大桥桥基工程中的使用效果,从理论上分析了该钻具的防斜原理。  相似文献   

不同地震烈度下边坡稳定性计算实例   总被引：3，自引：0，他引：3  

晓凡 《东北地震研究》1999,15(1):59-64

按照工程场地地震安全性评价的有关规定，在充分研究场地工程地质，地震地质背景等工作的基础上，采用ＢＩＳＨＯＰ法以某拟建工程场地在不同地震烈度下其边坡的稳定性进行了计算。  相似文献   

Changes to dam safety management in British Columbia triggered by failure of a small earth dam     

Dwayne D. Tannant 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(3):148-157

The Testalinden earth dam in southern British Columbia failed in June 2010 and created a huge debris flow. Homes were destroyed and property was damaged. The failure of this small dam resulted in a comprehensive review of over 1000 dams in the province, evaluation of dam safety management practices, changes to the Water Act and improvements in how data on dams are collected, archived and communicated. The provincial dam inventory was re-evaluated to ensure that appropriate consequence classification, and therefore attention, is assigned to dams. Increased scrutiny was placed on dam owners to ensure they complied with dam safety policies and to ensure they submitted annual inspection reports and formal dam safety reviews in a timely manner. Dam owners and professionals engaged in dam safety activities have received new guidelines and better education and training.  相似文献