Petroleum well drilling monitoring through cutting image analysis and artificial intelligence techniques

Petroleum well drilling monitoring has become an important tool for detecting and preventing problems during the well drilling process. In this paper, we propose to assist the drilling process by analyzing the cutting images at the vibrating shake shaker, in which different concentrations of cuttings can indicate possible problems, such as the collapse of the well borehole walls. In such a way, we present here an innovative computer vision system composed by a real time cutting volume estimator addressed by support vector regression. As far we know, we are the first to propose the petroleum well drilling monitoring by cutting image analysis. We also applied a collection of supervised classifiers for cutting volume classification.     

基于自相似理论802．11业务量特性的数学模型分析

探讨了种用自相似理论建立802.11业务量特性的数学模型，给出并验证了丢包率PLR与分配给该无线链路的带宽间的函数关系。     

基于图论的多定压节点管网水力计算方法的研究

多定压节点管网具有复杂的拓扑关系,可充分发挥图论的优势对其进行水力计算.通过引入虚节最和虚环的概念将多定压节点问题转化为单定压节点问题,对相关矩阵按照定压和非定压节点、虚管段和实际管段、树支和链支管段进行分块表示.推导出了采用链支流量矩阵进行管网水力计算的解析表达式,在此基础上得到了适于计算机求解的离散模型,同时将此方法应用于实际算例并与Hardy Cross法的计算结果进行了对比.     

Serviceability of earthquake-damaged water systems: Effects of electrical power availability and power backup systems on system vulnerability

Civil infrastructure systems, such as water, electrical power, natural gas, and transportation systems, are essential to the smooth functioning of modern society. Because of their inter-connected nature, once one infrastructure system is damaged by an earthquake or other natural hazard, other infrastructure systems may malfunction as well. A number of previous studies have assessed vulnerability of infrastructure systems to earthquakes, but seldom have failures due to infrastructure system interactions been considered. In its assessment of the earthquake-induced damage of a municipal water system, this paper includes the impact of damage to the supporting electrical power system using a fault tree analysis and a shortest-path algorithm. The effect of uncertainty of seismic intensity and component fragility on network integrity is evaluated. A case study involving a simple model of the electrical power system and water system in Shelby County, TN, which includes the city of Memphis, demonstrates the importance of taking infrastructure interactions into account when evaluating the seismic vulnerability and risk to a networked system, as well as the utility of back-up power systems in electric power facilities.     

Prediction of tunneling-induced ground movement with the multi-layer perceptron

This paper presents a method to predict ground movement around tunnels with artificial neural networks. Surface settlement above a tunnel and horizontal ground movement due to a tunnel construction are predicted with the help of input variables that have direct physical significance. A MATLAB based multi-layer backpropagation neural network model is developed, trained and tested with parameters obtained from the detailed investigation of different tunnel projects published in literature. The settlement is taken as a function of tunnel diameter, depth to the tunnel axis, normalized volume loss, soil strength, groundwater characteristics and construction methods. The output variables are settlement and trough width. Parameters for the prediction of horizontal ground movement include diameter to depth ratio (D/Z), unit weight of soil and cohesion. The neural network demonstrated a promising result and predicted the desired goal fairly successfully.     

CALCULATING MAXIMUM ENTROPY FLOWS IN MULTI-SOURCE,MULTI-DEMAND NETWORKS

Previous work has shown how maximum entropy flows in a water distribution network can be calculated by maximizing a nodal entropy function. This requires the use of numerical nonlinear optimization. In the case of single-source networks a much simpler path entropy formulation exists which permits solutions to be obtained quickly by manual calculations not requiring numerical optimization. This paper extends the path entropy formulation to general multi-source, multi-demand networks and develops a simple manual calculation method for maximum entropy flows in these general networks. The method is quick, non-iterative and does not directly involve the use of numerical optimization. Examples are presented and discussed.     

Some observations on energy loss and network entropy in water distribution networks

The design of water distribution networks has been extensively studied with the aid of computers, and the focus has shifted from merely satisfying the hydraulic requirements to fulfilling the need for reliability. One of the interesting research areas recently is the use of informational entropy as a surrogate measure for reliability. The actual meaning of the informational entropy for water distribution network has not been fully elucidated, and it was hypothesed that reliability is in some way proportional to the numerical value of network entropy. The purpose of this paper is to explore the relationship between energy loss and network entropy. The investigation approach used is to take a simple looped network and individually vary the pipe diameters from zero to infinity, and calculate the corresponding network entropy and energy loss for the water distribution network. The results revealed many interesting observations in the variation of network entropy with pipe resistance coefficient K _i , and the revelation of local maximum and minimum points.     

基于贝叶斯神经网络的冲击地压预测与影响因素权重分析

针对华丰煤矿4#煤层冲击事故频发的问题,采用理论分析及现场实验相结合的方法,对于复杂开采技术类因素和多种典型性地质条件耦合作用下的冲击地压启动机理、能量来源及防治措施展开研究。首先分析4#煤层1411工作面冲击启动能量来源,通过建立工作面前方煤体及围岩结构承受动、静载荷的力学模型,得到冲击启动区煤体内部任意一点的应力解析解,其次基于弹塑性理论,通过主应力平面偏转变换得出的最大、中间和最小主应力求得冲击启动区任意处单元煤体储存的弹性应变能的解析解,并根据现场实际工程参数,分析各种因素对煤体内部应力和能量分布规律的影响。结合力学模型解析解、数值模拟实验和现场记录参数的结果对工作面前方冲击地压的启动、传递和显现进行预测和分析。通过对冲击地压影响因素权重的分析发现了通过水力压裂降低顶板强度或水射流切割顶板降低老顶悬臂梁长度等对工作面防冲治理的优先级应高于保护层开采卸压等手段。     

基于用户消费习惯多选权重的垂直切换算法

针对现有异构网络垂直切换算法未能充分考虑不同用户以及同一用户不同次通信对网络资源需求有所不同的问题,提出了一种基于用户消费习惯的多选权重垂直切换算法(MWVH)。算法通过计算用户近期实时业务和非实时业务消费的期望、方差以及消费频率动态改变候选网络切换利润函数中的指标权重,得到符合用户近期消费习惯的网络选择。     

基于ZigBee协议的无线传感器网络服务质量的研究

针对于无线传感器网络的发展,以及新型的协议规范ZigBee协议在无线传感器网络中广泛应用,以分析研究基于ZigBee协议的无线传感器网络的服务质量的评价机制为目的。通过对无线传感器网络及ZigBee协议的组成、通信特点的研究,以及结合传统网络的QoS评价机制,最终总结得到可以从5个方面来评价ZigBee协议的无线传感器网络的服务质量。