PHAST软件对液化天然气泄漏扩散的研究

天然气在现代生活中应用越来越广泛,为了在紧急情况下能够正常供应液化天然气,我国的部分城市已建造了大型液化天然气储罐。由于液化天然气易燃易爆性,模拟其发生火灾爆炸的可能性具有重大的借鉴作用。本文运用挪威DNV公司研制的PHAST软件输入发生事故时的真实场景,包括设备类型,物质种类,存储参数,泄漏方式,周围环境(大气温度、湿度、稳定度、风速)等设置,模拟液化天然气储罐发生不同的泄漏事故,绘出能够真实描述事故危害的计算机图表、报告等评价结果。运用PHAST软件模拟得出不同的孔径,不同的风速,不同大气稳定度的条件下,泄漏扩散浓度定量分析的结果,通过下风向距离,云团宽度来描写火灾爆炸区域,为提高我国液化天然气的安全管理水平,降低事故风险提供依据。     

An intuitionistic fuzzy system for time series analysis in plant monitoring and diagnosis

We describe in this paper a proposed new approach for fuzzy inference in intuitionistic fuzzy systems. The new approach combines the outputs of two traditional fuzzy systems to obtain the final conclusion of the intuitionistic fuzzy system. The new method provides an efficient way of calculating the output of an intuitionistic fuzzy system, and as consequence can be applied to real-world problems in many areas of application. We illustrate the new approach with a simple example to motivate the ideas behind this work. We also illustrate the new approach for fuzzy inference with a more complicated example of monitoring a non-linear dynamic plant.     

煤矿瓦斯预测专家系统中基于粗集的知识获取方法

针对现有煤矿瓦斯预测专家系统因没有新知识获取措施及知识自更新功能而预测效果不佳的问题,提出了基于粗集的知识获取方法。该方法首先建立瓦斯数据与瓦斯突出强度之间关系的预测样本集;然后运用粗糙集的连续属性离散化、属性约简以及规则提取算法,从大量的预测样本集中自动获取预测知识,并将预测知识存储于专家系统知识库中;最后基于推理机实现煤矿瓦斯突出的实时预测。实例分析验证了该方法在煤矿瓦斯突出预测专家系统知识获取中的有效性和实用性。     

家用天然气泄漏监控系统设计

利用基于AT89S52单片机控制模块和PT2272、PT2262编码解码的DF无线通信模块开发了一种新的天然气泄漏监控系统,利用MQ-4气敏传感器作为气体浓度检测器件。系统能在可燃气体泄漏时,发出控制指令,实现声、光报警,同时通过自动装置关闭气阀,并打开排风扇,以处置危险。该系统在无人环境下实现自动报警和危险处置的功能,最大程度确保了天然气使用过程中人身和财产的安全。     

天然气与煤联合气化的热力学模拟研究

天然气与煤联合气化工艺通过改变进料条件,能够直接得到H2／CO比可调合成气。为探索进料条件对合成气H2／CO比和温度的影响规律,本文建立了描述天然气与煤联合气化制合成气热力学模型,根据该模型计算了不同进料条件对合成气H2／CO和出口温度的影响。计算结果表明,进料中CH2／O2比例的增加可同时显著提高合成气的H2／CO比和降低反应温度;进料中H2O／O2比例的增加只是显著降低反应温度,而对合成气H2／CO比的影响较小;提高进料温度和操作压力对合成气生产有利。     

非线性末制导系统参数灵敏度分析

末制导系统参数随着飞行环境及飞行条件的改变而存在摄动,针对这一问题本文提出根据动态灵敏度来分析参数摄动对脱靶量的影响.基于伴随法推导出与系统动态方程相同规模的伴随方程,并通过一次伴随求解计算得到脱靶量对所有可调参数及摄动参数的动态灵敏度,有效的提高了计算效率.传统的直接分析法是将系统状态变量直接对参数变量进行微分,需要对每个参数变量求解一组代数或微分方程,对于状态变量及参数变量较多的情况效率较低.本文基于两种方法对末制导系统的参数灵敏度进行分析,分析结果揭示了参数摄动对脱靶量的影响程度,较小的参数灵敏度为提高系统的鲁棒性提供了依据.     

A comparative analysis of score functions for multiple criteria decision making in intuitionistic fuzzy settings

The purpose of this paper was to conduct a comparative study of score functions in multiple criteria decision analysis based on intuitionistic fuzzy sets. The concept of score functions has been conceptualized and widely applied to multi-criteria decision-making problems. There are several types of score functions that can identify the mixed results of positive and negative parts in a bi-dimensional framework of intuitionistic fuzzy sets. Considering various perspectives on score functions, the present study adopts an order of preference based on similarity to the ideal solution as the main structure to estimate the importance of different criteria and compute optimal multi-criteria decisions in intuitionistic fuzzy evaluation settings. An experimental analysis is conducted to examine the relationship between the results yielded by different score functions, considering the average Spearman correlation coefficients and contradiction rates. Furthermore, additional discussions clarify the relative differences in the ranking orders obtained from different combinations of numbers of alternatives and criteria as well as different importance conditions.     

基于LabVIEW的航空发动机气路故障分析系统设计

针对在航空发动机气路中带电粒子的电荷信号微弱,传感器工作环境恶劣的条件下,监测航空发动机气路故障的问题,设计了一种能适应高温、高噪声等恶劣工作环境并对电荷信号灵敏监测模型,使用LabVIEW软件建立了航空发动机气路不同工况中静电信号的子V1,对信号进行采集和分析.通过对航空发动机多种工况的模拟和试验,建立了航空发动机气路故障分析系统.结果表明:该监测模型分辨率高、信噪比高、稳定性好,可稳定地监测航空发动机的多种工况,为航空发动机气路故障诊断提供可靠的依据.     

基于灰色系统理论的瓦斯含量多变量可视化预测方法实现

针对煤矿瓦斯含量预测采用单因素梯度法存在可靠性不高的问题,提出了一种基于灰色系统理论的瓦斯含量多变量可视化预测方法,建立了预测模型的总体框架,给出了动态链接库实现灰建模数值算法的流程;并结合某矿实际,详细介绍了该预测方法的具体实现过程:首先通过数字化瓦斯地质图获取瓦斯含量原始数据,设置建模所需的相关参数,建立瓦斯含量多变量预测模型,选择瓦斯含量点击预测或批量预测,对预测结果的误差进行分析并与图形信息结合起来显示。该预测方法提高了预测的效率及决策的科学性,为煤矿日常瓦斯含量预测、管理及决策提供了一个直观、方便、高效的可视化预测手段。     

一种压差式车用气体流量传感系统的设计

介绍了一种车用压差式气体流量传感系统的结构设计和测量电路,指出了传感器的使用范围。通过实验测出了其特性曲线,并对影响测量误差的因素进行了分析,可满足车用发动机曲轴箱窜气量参数的检测,为发动机不解体故障诊断提供了一种新的测试方法。     

超大型天线馈源舱柔索支撑结构动力学分析与跟踪控制

根据悬链线解析表达式推导出柔索两端固定时索端拉力与索长之间的关系,用于求解特定长度的驱动柔索对处于某一位姿的馈源舱作用力,在此基础上应用Newton-Euler法建立了超大型射电望远镜馈源舱柔索支撑系统的简化动力学模型.采用具有二次收敛性的Newton-Raphson迭代法进行求解,得到较快的求解速度以满足实时控制要求.针对该系统的非线性、慢时变、多变量耦合等特点,提出了一种自适应双模糊控制器来实现馈源舱轨迹跟踪.该控制器采用模糊推理完成两组控制器的平稳过渡.最后,通过仿真计算结果验证了该控制策略的有效性.     

Development of an expert system for optimizing natural gas pipeline operations

This paper presents an expert system as a decision support tool to optimize natural gas pipeline operations. A natural gas pipeline control system is a controlling system that involves many complicated operating processes. Since a dispatcher (who operates the system) might not be able to handle all of his or her tasks consistently, an expert system has been developed for optimizing the operations by providing consistent, fast and reliable decision support to the dispatcher. Consequently, inconsistency in the dispatcher's performance can be minimized. To build an expert system, the knowledge from an experienced dispatcher, who is familiar with the process in this controlling system is acquired and that knowledge has been implemented as rules in the knowledge base of the expert system. When this expert system has been validated by gas pipeline experts, it can help inexperienced dispatchers to operate the processes more effectively. The expert system is implemented on the real-time expert system shell G2 (trademark of Gensym Corp. of USA). The system also consists of a user interface that helps dispatchers visualize system conditions.     

基于模糊分析的信息系统风险灰色评估模型

为了准确地评价信息系统风险,提出了一种融合模糊层次分析法和灰色评估方法的新模型.从“灰度”概念出发,建立信息系统风险灰色评估模型,消减评价者的主观性.在此基础上引入模糊层次分析法,该方法通过引入模糊数学的有关概念对权重的确定方法进行改进,确保了权重选择的客观性.对信息系统风险的实证进行了研究,实验结果表明了该方法的有效性,为进一步提高信息系统风险评估的准确性提供了可参考的模型和方法支持.     

信息系统中属性约简的矩阵算法

属性约简是知识发现的重要课题,也是粗糙集理论的核心问题之一。主要通过定义关系矩阵、上（下）分布矩阵、模糊上（下）分布矩阵和决策矩阵,用矩阵算法计算信息系统中变精度粗糙集模型的上（下）分布约简和模糊目标信息系统中的上（下）分布约简以及决策约简。     

室内温湿度及燃气泄露监测系统

家庭安全—直是人们关注和担心的话题。随着社会的进步,人民生活质量不断提高,家庭安全问题却愈发严重。基于物联网技术的室内温湿度和燃气泄露监测系统能够实时掌握室内的温湿度状况,并在温度过高或可燃气体（一氧化碳）浓度过高时自动报警,能够尽早发现问题并及时处理,为人们的家庭安全保驾护航。     

A rolling horizon approach for stochastic mixed complementarity problems with endogenous learning: Application to natural gas markets

In this paper we present a new approach for solving energy market equilibria that is an extension of the classical Nash-Cournot approach. Specifically, besides allowing the market participants to decide on their own decision variables such as production, flows or the like, we allow them to compete in terms of adjusting the data in the problem such as scenario probabilities and costs, consistent with a dynamic, more realistic approach to these markets. Such a problem in its original form is very hard to solve given the product of terms involving decision-dependent data and the variables themselves. Moreover, in its more general form, the players can affect not only each others׳ objective functions but also the constraint sets of opponents making such a formulation a more complicated instance of generalized Nash problems. This new approach involves solving a sequence of stochastic mixed complementarity (MCP) problems where only partial foresight is used, i.e., a rolling horizon. Each stochastic MCP or roll, involves a look-ahead for a fixed number of time periods with learning on the part of the players to approximate the extended Nash paradigm. Such partial foresight stochastic MCPs also offer a realism advantage over more traditional perfect foresight formulations. Additionally, the rolling-horizon approach offers a computational advantage over scenario-reduction methods as is demonstrated with numerical tests on a natural gas market stochastic MCP. Lastly, we introduce a new concept, the Value of the Rolling Horizon (VoRH) to measure the closeness of different rolling horizon schemes to a perfect foresight benchmark and provide some numerical tests on it using a stylized natural gas market.     

电–气互联系统的气电解耦分布式多目标优化调度

本文基于能源互联网背景建立了一种计及供能成本、碳排放量和净负荷曲线平滑度的电–气互联系统多目标优化模型,并采用线性化方法将非线性优化模型转化为混合整数线性规划模型.同时,为了求解该模型,实现各能源的协同互补利用,提高能源的利用率,本文在保障各能源网络分散自治权的基础上提出一种基于气电解耦的分布式多目标优化算法,以气电解耦优化的方式实现电、气系统的分散自治.所提算法将原系统的多目标优化问题分解为电网和气网的子优化问题,并采用独立的优化器完成子问题的求解.电网和气网仅需交换少量边界变量以及虚拟目标因子分别进行全局调整即可获得多目标解.最后,本文根据修改的IEEE 39节点电力网络和比利时20节点天然气网络搭建模型并进行仿真分析,结果验证:所提算法能够完成电–气互联系统的气电解耦并实现多目标并行求解,从而提高系统信息私密性、实现各能源网络的分散自治.     

可燃气云爆炸事故后果的概率分析

对事故后果进行分析．是安全评价的重要内容。可燃气体泄漏后发生蒸气云爆炸是一种重要的事故类型,由于人们对事故后果认识的局限、环境的影响、以及事故发展过程的复杂性,VCE后果分析中许多参数未能准确定义,部份输入参数取值具有随机性,不同取值使最终的分析结果相差很大。本文提出了一种事故后果的概率分析方法。通过事故的后果(死亡半径)及其发生的概率来反映后果严重程度,并基于蒙特卡罗模拟方法来计算事故后果的发生概率。本文对给定发生概率时如何确定死亡半径也进行了分析,采用基于支持向量机(SVM)的非线性回归估计方法对死亡半径进行估计。分析了VCE后果分析模型中的随机性参数及其取值,结合具体的应用实例,说明了该方法在LPG储罐蒸气云爆炸后果分析中的应用。     

A real-time system for pattern recognition of human sleep stages by fuzzy system analysis

A pattern recognition system for the analysis of human sleep stages using the EEG data is presented. The system is designed by using concepts of the fuzzy system analysis and it is implemented in hardware for real-time applications.     

基于数据仓库的房地产数据分析系统

针对房地产信息系统积累的大量房产数据,研究并实现基于数据仓库及OLAP技术的房地产智能数据分析系统.首先建立了分离的数据仓库,并对数据仓库进行多维建模和多维分析;然后对多维数据模型进行了切片、切块,旋转、上钻和下钻等多维分析,从多角度进行房产数据分析,并计算房产指数;最后利用前端开发工具开发了可视化的多维分析和数据展示平台.实践表明,基于数据仓库的房产数据分析系统可以为房地产管理层和决策层提供高效的决策支持.