气体检测系统中BP神经网络的设计与实现

在简要概述气体检测系统原理的基础上,分析了BP神经网络模式识别的特性和结构,阐述了一种基于人工神经网络的混合气体检测方法。分析并研究了气体检测系统中BP神经网络结构的设计方法,构建了基于Matlab的BP网络模型,并实现了对CO、H2S和CH4三种混合气体的定性定量检测。     

探析公路高瓦斯隧道瓦斯治理费用测算

水盘高速公路发耳隧道为高瓦斯隧道,地处煤与瓦斯突出矿区,设计穿越17层煤,穿越的煤层具有煤与瓦斯突出危险性,设计吨煤瓦斯含量为8.63m3,实测煤层吨煤瓦斯含量最高为12.96m3。发耳隧道严格按照井工开采模式进行施工管理,与普通隧道相比,施工费用大幅度提高,作者通过施工实践总结,探析高瓦斯隧道施工费用增加部分的测算方法。     

东营市天然气运营管理及对策研究

本文从东营市当前天然气运营管理现状、燃气行业的供求矛盾、燃气市场的经营秩序等方面入手分析了东营市燃气行业发展存在的问题,针对存在的问题提出了如下对策及建议,即采取政府主导并引进天然气气源、建设高压管网、实现特许经营、完善配套管理机制及实施价格联动机制等方式,为燃气行业发展创造一个良好的内外部环境。     

TORNADO燃机故障诊断的神经网络模型研究

为改善单神经网络收敛速度慢的问题,本文采用组合神经网络建模方法,建立了燃机性能仿真网络模型,并进行实验验证。建模过程中,将建模对象划分为三个相对独立的子网络,利用获取的实验数据组成训练域对网络进行训练,建立起一套可用于燃气轮机控制系统仿真及故障诊断的组合神经网络模型。实验结果表明:该模型平均输出误差约为3%-6%,计算时间小于100ms,可用于基于模型的燃气轮机诊断系统。     

城市燃气企业运行成本分析模型构建研究

本文将城市燃气企业配气运行成本划分为人工成本、总折旧费和运营成本三类,将通过分析企业职工总数和固定资产原值情况,间接研究企业所有人工成本和折旧费情况,而直接对企业运营成本进行研究。通过相关性分析与多元线性回归理论构建了城市燃气企业运行成本分析模型,并进行了实例应用研究。此外,具体阐述了城市燃气企业运行成本分析的重要意义。     

基于TOPSIS法的天然气集输管网规划方案决策

天然气集输管网系统庞大而复杂,而管网最优规划是在气田开发地面工程建设中必须首先解决的问题。本文采用TOPSIS多目标决策法对天然气集输管网工程的规划方案集进行评价,并首次在方案整体评价中把环境条件(如穿越河流、穿越公路、管线护坡工程)对投资、施工、管理的影响综合进行考虑。用该方法对实例中的8个预选方案进行综合评价,选出了技术上可行、经济上合理、符合工程要求的最佳规划设计方案。     

Distribution free estimation of heteroskedastic binary response models using Probit/Logit criterion functions

In this paper estimators for distribution free heteroskedastic binary response models are proposed. The estimation procedures are based on relationships between distribution free models with a conditional median restriction and parametric models (such as Probit/Logit) exhibiting (multiplicative) heteroskedasticity. The first proposed estimator is based on the observational equivalence between the two models, and is a semiparametric sieve estimator (see, e.g. Gallant and Nychka (1987), Ai and Chen (2003) and Chen et al. (2005)) for the regression coefficients, based on maximizing standard Logit/Probit criterion functions, such as NLLS and MLE. This procedure has the advantage that choice probabilities and regression coefficients are estimated simultaneously. The second proposed procedure is based on the equivalence between existing semiparametric estimators for the conditional median model (,  and ) and the standard parametric (Probit/Logit) NLLS estimator. This estimator has the advantage of being implementable with standard software packages such as Stata. Distribution theory is developed for both estimators and a Monte Carlo study indicates they both perform well in finite samples.     

Gas system failure rate

Gasunie buys and sells gas. This paper is about calculating the failure rate of the gas transport system of Gasunie in the Netherlands. The pipes in the network are connected at certain stations which may operate at degraded levels due to technical problems. The transport system, modelled as an optimization problem, needs to be checked for feasibility for every configuration of the degradation levels at all stations in order to see whether the system fails or not. The discrete probability distributions of the degradation levels at every station in the network are given. The number of possible combinations of degradation levels is huge and the computations for the feasibility of the gas network are computer-intensive. This paper presents a new algorithm for approximating this rate and it is parsimonious in actually checking for feasibility.     

城镇燃气施工中的管道接口质量控制探讨

随着城镇燃气管网的不断发展,因燃气泄漏等引起的安全事故时有发生,因此,人们对城镇燃气施工的质量越来越重视.在城镇燃气施工中,管道接口的质量关系着整个城镇燃气管网的运行质量及安全.城镇燃气管道施工中常用的管材包括PE管、镀锌管及钢管三种,基于此,文章以城镇燃气施工为背景,从管道接口质量控制入手,分别分析了PE管、镀锌管及...     

天然气下游价格风险传导模型研究

本文通过分析天然气下游价格风险的传导途径,提出了应用沙堆模型分析了天然气下游价格风险的传导机理,并模拟了其价格雪崩过程。结合前人的研究成果,判断该风险传导网络是无标度网络。得出结论,只有提高每一位利益相关者的风险忍受阀值和控制该系统的Hub点的行为,才能有效的控制整个下游价格风险传导网络。     

Analysis of failure time using threshold regression with semi‐parametric varying coefficients

Many new statistical models may enjoy better interpretability and numerical stability than traditional models in survival data analysis. Specifically, the threshold regression (TR) technique based on the inverse Gaussian distribution is a useful alternative to the Cox proportional hazards model to analyse lifetime data. In this article we consider a semi‐parametric modelling approach for TR and contribute implementational and theoretical details for model fitting and statistical inferences. Extensive simulations are carried out to examine the finite sample performance of the parametric and non‐parametric estimates. A real example is analysed to illustrate our methods, along with a careful diagnosis of model assumptions.     

气井新型柱塞排液采气工艺技术及应用

采气工艺技术是气田开采的关键。现阶段气井环境过于复杂,采气工艺需要不断适应更复杂的条件。本文从国内外排液采气技术现状出发,重点探讨了柱塞排液排液采气工艺技术的应用,并提出了发展建议,具有一定参考价值。     

煤气流量计量仪表选型的探讨

测量煤气的计量方式有三种,都是对流量的一种计量方式,这样不同的仪表计量方式都是通过流量的测量优点和原理上开始对其进行分析和整理。     

人工煤气置换天然气后居民燃气表更换的探讨

国家"西气东输"项目的实施,给沿途城市的天然气利用带来了良好机遇,原来使用人工煤气作为气源的城市燃气置换为天然气成为必然趋势,其中用于居民燃气计量的煤气表更换成为煤气置换工程中关键的环节之一。本文主要对人工煤气置换为天然气后煤气表更换的必要性、IC卡煤气表的特点及其使用上的优势和社会综合效益进行了探讨分析。     

Weighted least squares estimators in possibly misspecified nonlinear regression

The behavior of estimators for misspecified parametric models has been well studied. We consider estimators for misspecified nonlinear regression models, with error and covariates possibly dependent. These models are described by specifying a parametric model for the conditional expectation of the response given the covariates. This is a parametric family of conditional constraints, which makes the model itself close to nonparametric. We study the behavior of weighted least squares estimators both when the regression function is correctly specified, and when it is misspecified and also involves possible additional covariates.     

Testing for multivariate volatility functions using minimum volume sets and inverse regression

We propose two new types of nonparametric tests for investigating multivariate regression functions. The tests are based on cumulative sums coupled with either minimum volume sets or inverse regression ideas; involving no multivariate nonparametric regression estimation. The methods proposed facilitate the investigation for different features such as if a multivariate regression function is (i) constant, (ii) of a bathtub shape, and (iii) in a given parametric form. The inference based on those tests may be further enhanced through associated diagnostic plots. Although the potential use of those ideas is much wider, we focus on the inference for multivariate volatility functions in this paper, i.e. we test for (i) heteroscedasticity, (ii) the so-called ‘smiling effect’, and (iii) some parametric volatility models. The asymptotic behavior of the proposed tests is investigated, and practical feasibility is shown via simulation studies. We further illustrate our methods with real financial data.     

佳木斯市佳西区域燃气中压B管道提压运行初步分析

文章阐述了对佳木斯市区域燃气中压B管道提压运行的几点看法,随着城市居民生活水平的提高,对燃气管网提压运行是可行的。     

瓦斯监控预警信息实时发布平台研究与应用

GSM网络将瓦斯异常值以短信形式发送到各级管理人员手机上进行预警,管理人员结合公司的联网监控系统能及时了解井下瓦斯异常情况,分析瓦斯异常原因,制定防范措施。有效的避免了瓦斯超限事故,保证了矿井的安全生产。     

Parametric and semi-parametric modelling of vacation expenditures

We analyse several limited dependent variable models explaining the budget share that Dutch families spend on vacations. To take account of the substantial number of zero shares, two types of models are used. The first is the single-equation censored regression model. We estimate and test several parametric and semi-parametric extensions of the Tobit model. Second, we consider two-equation models, in which the participation decision and the decision on the amount to spend are treated separately. The first decision is modelled as a binary choice model; the second as a conditional regression. We estimate and test parametric and semi-parametric specifications.     

城镇燃气标志与燃气设施保护的重要性

近年来随着我国燃气用量快速增长和城镇燃气基础设施的大规模建设,不同压力级别、不同气质、不同用途的燃气厂站、燃气管道的投运量与日俱增。由此给燃气安全供应、安全使用及安全管理提出了更高的要求。城镇燃气标志渐渐在安全生产中起着越来越重要的作用,正确使用城镇燃气标志可提醒人们注意某种危险因素的存在,从而减少或避免事故的发生。燃气法规也要求燃气经营者在燃气设施及相关场所设置城镇燃气标志,使得对燃气设施的保护和管理更加规范。