A condition assessment model for oil and gas pipelines using integrated simulation and analytic network process

Even though they are safe and economical transportation means of gas and oil products around the world, pipelines can be subject to failure and degradation generating hazardous consequences and irreparable environmental damages. Therefore, gas and oil pipelines need to be effectively monitored and assessed for optimal and safe operation. Many models have been developed in the last decade to predict pipeline failures and conditions. However, most of these models used corrosion features as the sole factor to assess the condition of pipelines. Therefore, the objective of this paper was to develop a condition assessment model of oil and gas pipelines that considers several factors besides corrosion. The proposed model, which uses both analytic network process and Monte Carlo simulation, considers the uncertainty of the factors affecting pipeline condition and the interdependency relationships between them. The performance of the model was tested on an existing offshore gas pipeline in Qatar and was found to be satisfactory. The model will help pipeline operators to assess the condition of oil and gas pipelines and hence prioritise their inspections and rehabilitation requirements.     

基于 FAHP-BN 的军队工程代建模式风险评估方法

为解决军队工程代建模式风险评估过程中的主观性与不确定性,提出一种模糊层次分析法与贝叶斯网络相结合的风险评估方法。以军队代建工程质量安全事故数据为基础,建立模糊层次分析模型对代建工程风险损失权重进行评估。构建贝叶斯网络,利用 Netica 软件推理风险事件发生概率。结合风险等级隶属函数,得出代建工程整体风险等级。该方法可以有效降低风险评估的主观因素,及时发现高风险节点,更准确地把握风险态势。实例评估结果与工程实际相符,验证了评估方法的合理性和适用性,对工程代建模式风险评估具有一定的参考价值。     

基于风险视角的国际PPP 项目投标决策模型研究

构建一个规范化的投标决策模型,将有利于国际PPP 项目投资者投标决策的科学性和有效性。根据国际PPP 项目的特点,以风险管理为视角,在系统分析投标决策影响因素的基础上,构建出国际PPP 项目投标决策模型。该模型主要包括投标决策流程和辅助投标决策的计算工具两个部分,投资者采用该模型能够得到各个风险因素的重要性排序、项目的整体风险水平和企业对风险的控制与承受能力评价结果,并以此作为科学决策的依据。并通过算例演示了该模型在国际PPP 项目投标决策中应用的可行性和适用性。     

Deterioration modelling of small-diameter water pipes under limited data availability

Low value and high volume buried infrastructure assets in the water distribution network are typically less well understood and often sub-optimally managed in comparison to more critical or higher value assets. This is despite attracting an estimated yearly expenditure from water utilities operating in the developed world in excess of £4.42 billion per annum. To address this problem the authors have developed a novel deterioration modelling framework founded on latest geospatial technologies and statistical analysis. The modelling framework is specifically applied to truly small diameter water distribution assets of 25–50 mm diameter. Reliability curves are developed from failure data provided by two UK Water Companies that have captured communication pipe failure records since 2001. Failure projections based on deterioration modelling curves are compared and contrasted to demonstrate the robustness of this modelling approach. A high degree of accuracy is observed for all pipe materials achieving an R² values greater than 0.96.     

多级模糊层次分析法在农村公路养护管理工作中的应用研究

为提高农村公路养护管理水平,分析了农村公路养护管理工作效果的影响因素,建立了多层的农村公路养护管理工作考核评价指标体系。应用多级模糊综合评价方法对不同乡镇的农村公路养护管理工作进行评估考核,并进行了等级排名。结果表明,该方法很好地体现出农村公路养护管理工作评估的模糊性和主观性。     

基于AHP模糊评价在隧道稳定性分析中的应用

对掌子面稳定性分析,有助于采取相应的技术措施,提高隧道施工的安全管理水平。文中通过对模糊评价和层次分析法分析过程的介绍,采用模糊评价法对影响掌子面稳定性因素进行综合分析,结合层次分析法计算各影响因素的权重,提高了分析结果的可靠性。分析结果表明,基于层次分析法的模糊评价可以定量的分析出隧道掌子面稳定性情况以及影响稳定性的主要因素。     

AHP模糊综合评价法在高校教师工作满意度研究中的应用

文章从对高校的认可、对工作本身满意度、对工作群体满意度、对工作回报满意度、对工作环境满意度五方面构建了高校教师工作满意度评价指标体系,通过AHP方法找到该检测的指标和权重,建立了多级模糊综合评价模型,最后通过实例说明了该方法的使用。     

基于改进层次分析法的小城镇供水消毒工艺的选择

小城镇消毒工艺的选择是一个多因素、多目标的决策过程。根据小城镇及其供水特点,选取游离氯、氯胺、二氧化氯、紫外线和臭氧五种消毒工艺为研究对象,将评价过程中的定性和定量指标分别处理,并运用模糊理论,对传统层次分析法做出改进,为小城镇选择实际、经济、有效的消毒工艺提供科学的评价方法。     

项目融资风险的模糊综合评价方法研究

针对项目融资的风险评价问题,首先运用动态分析方法对项目融资的投资风险和融资风险做出了定量的分析,然后通过层次分析法建立了项目融资风险的评价指标体系,最后运用模糊综合评价法得出评价结果,为准确全面评价项目融资的风险提供了理论依据。     

基于多种方法综合的援外工程风险定量分析

针对援外工程的特点,利用工程风险分析的多种方法结合,以巴基斯坦喀喇昆仑公路桥梁修复工程为例进行风险的定量分析,以提高风险分析的可靠性,从而提高经济效益。     

Value of information-based decision analysis of the optimal next inspection type for deteriorating structural systems

Deteriorating infrastructure systems require inspections and maintenance to ensure safe operation. System operators are often required to decide the optimal type of inspection to perform, where some inspections are of higher accuracy, and correspondingly higher cost. Life cycle analysis is typically used to determine the optimal inspection type. While life cycle analysis is effective at determining the optimal inspection type, it is also inefficient, requiring analysis of the entire decision sequence throughout the system life cycle. This paper presents an efficient methodology to approximate the decision of the optimal next inspection type without performing a life cycle analysis. This methodology determines the range of the value of information provided by only the next inspection. When the inspection cost is outside the range of the value of information then this method yields the decision of which inspection type to choose, negating the need for life cycle analysis. When the inspection cost for some inspection types lies within the bounds then a subsequent life cycle analysis is required, but perhaps some inspection types can be eliminated, simplifying the life cycle analysis. Thus, this method is complimentary to life cycle analysis, functioning as a quick preliminary assessment. The methodology is demonstrated through a numerical example of a corroding pipeline.     

Condition-based maintenance decision support system for oil and gas pipelines

The 2013 report card of America's infrastructure has scored the condition of oil and gas pipelines as D+ which means that such pipelines are in a relatively poor condition. More than 10,000 failures have been recorded in the US. These failures have resulted in environmental, health and property damages. Therefore, there is a definite need to give more attention to the maintenance of oil and gas pipelines. This paper develops a comprehensive model for the maintenance planning of oil and gas pipelines. The model selects rehabilitation/repair alternatives for oil and gas pipelines based on their condition during their service life. These alternatives are then used to calculate the cash flow throughout the service life of these infrastructures. The model, which uses Monte Carlo simulation and fuzzy approach to address the uncertainties in the estimation of the maintenance operation costs and the economic parameters, calculates the Equivalent Uniform Annual Worth of the identified alternatives. The optimum maintenance programmes consist of the alternatives that have the lowest life cycle cost of oil and gas pipelines. The model is expected to support pipeline operators in the maintenance decision-making process of oil and gas pipelines.     

基于区间数模糊层次分析法的公路工程地质评价研究

目前,公路工程地质评价尚不成熟,无法定量地对工程地质条件的适宜性做出评价。本文应用区间数模糊层次分析法构建了工程地质评价模型,形成了一套完整的工程地质评价方法,将区间数理论和数模糊层次分析法结合,极大提高了数据的利用率,使评价结果更精确。以孔隙度为例,示范了指标层隶属度区间的确定方法,并求得5个岩石样品模糊集合为A=（0.1,0.05,0.25,0.2,0.2）,隶属度区间为[0.05,0.2]。     

基于模糊综合评价法的施工方案优选

施工方案评价的特点是既要考虑定量指标也要考虑难以量化的定性指标,即为多指标半结构性评价问题。本文将层次分析法、群组决策方法、非结构性决策理论和模糊综合评价法等理论应用于施工方案的评价中,将定性指标和定量指标相结合,很好地解决了这一问题。最后通过一算例验证了该方法的可行性和实用性。     

模糊评价法在公路隧道洞门效果评价中的应用

鉴于影响公路隧道洞门选择的因素很多,从设计、施工、运营及景观效果三个方面选取了洞门的评价因素,利用模糊层次分析法和模糊综合评价法进行综合评价,最后利用最大隶属度原则得出评价结论,通过现场洞门设置实例说明此综合评价方法效果良好,操作简单有效。     

建设项目管理信息系统开发风险评价研究

建设项目管理信息系统（PMIS）的发展并不成熟,其开发可能遇到技术、管理等多方面的风险。系统开发的管理者由于缺乏经验,对风险因素的管理主观、零散且盲目,导致开发项目的失败。本文综合层次分析法和模糊评估法对风险因素发生的概率、发生后的影响程度和综合影响程度进行量化,为管理者控制风险提供依据。     

基于成熟度的建筑供应链信息共享评价

当前建筑行业存在盈利水平低、建设成本高、管理模式落后等问题,信息共享是解决这些问题的有效途径,但是还缺乏对建筑供应链信息共享进行科学合理评价的方法。因此,本文将成熟度概念引入建筑供应链信息共享领域,并将建筑供应链信息共享程度划分为5个等级,用于度量其信息共享程度。再构建建筑供应链信息共享成熟度的综合评价指标体系,运用模糊层次分析来确定相关指标权重,并利用模糊综合评价法进行评价。最后以某公司为实例,进行相关评价,验证本文的思路及方法。为实施科学合理的建筑供应链信息共享评价提供了借鉴和理论依据。     

基于RBF神经网络的边坡稳定可靠度分析

RBF神经网络具有网络训练速度快、可以避免局部极小等优点。文章基于RBF神经网络理论,采用蒙特卡罗模拟法来进行结构的可靠度分析,研究了样本点的生成方法及样本数对可靠度分析结果的影响,并将基于RBF神经网络的蒙特卡罗模拟法应用于边坡的可靠度分析。计算表明:基于RBF神经网络的蒙特卡罗模拟法具有较好的计算效率和计算精度;样本点的生成方法和样本数对计算结果影响较大。与随机取样法相比,均匀设计法生成的样本点分布更均匀,由此样本点集训练生成的神经网络能更好的代替原功能函数,在相同的样本数时具有更高的计算精度;当计算精度相同时,均匀设计法比随机取样法需要生成的样本点少,计算效率高。     

上海某宾馆冷热源改造方案的比较分析

引入模糊综合评价法,以上海某宾馆冷热源改造方案选择为例,对3种备选方案进行了优选,提出适用于本工程的冷热源方案.