A fuzzy logic approach to model delays in construction projects using rotational fuzzy fault tree models

Delays in construction projects are inevitable and, as a result, claims and disputes arise. Different causes of delay can come into play and therefore the need to identify and classify different causes of project delay arises. Different factors that contribute to project delay affect the likelihood of project delay in different degree of effectiveness. Fuzzy fault tree analysis (FTA) is suggested by this research to estimate the likelihood of project delay. Likelihood of delay membership function is further quantified using the weighted average defuzzification method. Two fuzzy logic models are implemented into the fuzzy FTA, using Visual Basic software: the models discussed in this research are Baldwin's rotational model and the Angular model. Comparison between the two fuzzy logic models has been carried out. Validation of the fuzzy FTA computer model is performed. Validation of the model was performed for adequacy and applicability of the model. On average, the validation performed by independent construction engineers and fuzzy logic experts produced satisfactory results. The computer software suggested by this study is an attempt to assess the likelihood of the project delay, which helps reduce delays in construction projects that can cause time loss.     

工程进度拖延原因分析及解决

描述工程进度拖延原因分析及解决措施,进度拖延原因分析可采取的方法和进度拖延主要由哪几方面构成及解决进度拖延的措施主要应考虑的几个方面:1)基本策略;2)工期压缩问题;3)可以采取的赶工措施;4)压缩对象的合理选择。     

基于三角模糊数的输变电工程模糊综合评价

针对输变电工程风险评价中专家主观因素所占比例较高的现状,研究了主观和客观相结合的评价方法,利用网络分析法与模糊评判法构建模糊网络风险评价模型,从而对风险实施有效控制。根据输变电工程特征,分析了影响施工安全的综合因素,建立了输变电工程风险评价指标体系,并使用两两比较判断矩阵法计算风险指标权重,再利用模糊综合评判将二级指标整合,得到项目的综合风险水平。为解决模型主观偏好的弊端,构建过程加入风险维度,用三角模糊数处理决策过程中的模糊性,对模型做进一步改善。并以某输变电工程为例,验证该方法具有可行性。     

工程质量风险的模糊层次分析

将模糊数学与层次分析方法相结合 ,建立了模糊层次分析模型并应用于工程项目质量风险分析 .为质量风险辩识、估计和评价提供了一种主客观相结合的分析方法     

模糊理论与AHP相结合的BOT风险研究

BOT是国际上出现的一种新的融资与项目管理模式。分析了BOT项目的风险来源及构成 ,将模糊数学方法与AHP(层次分析法 )相结合 ,建立了模糊层次综合评判模型并用于对BOT项目风险评估的研究 ,为BOT项目风险辨识、估计和评价提供了一种主客观相结合的分析方法。     

工程项目时间/成本模糊集优化

从分析工程项目的时间／成本影响因素入手，综合考虑定性和定量因素，包括管理水平、管理复杂程度、资源分配情况等，提出了模糊集理论的时间／成本决策模型，从而促进工程项目时间／成本模糊集优化的研究。     

Analysis of cost and schedule performance of international development projects

This study focuses on cost and schedule issues of international development (ID) projects. Through empirical analysis we examine ID project cost and schedule performance and the main reasons for poor project outcome. We look at 100 projects that are sponsored by the Asian Development Bank and hosted by several Asian countries. The study identifies that most late projects experience cost underrun – an unusual cost and schedule variation relation in projects. Further we identify the root causes of project delay and cost underrun. Research findings will benefit ID project professionals, organizations and the ID project body of knowledge. The study can be extended to analyse other developing country projects sponsored by different donors.     

岩土边坡稳定性分析的模糊有限元方法研究

针对边坡工程稳定性评价的岩土力学参数的模糊性,研究了边坡稳定性分析的模糊有限元方法,并提出了边坡工程分析的模糊有限元快速求解方法。利用模糊有限元方法对实例边坡工程进行了模糊有限元研究,研究结果表明:岩体力学参数的模糊性会导致边坡位移和应力分析结果的模糊性,而采用模糊有限元分析方法对边坡进行分析可以增加工程技术人员对边坡位移、应力和安全度的全面认识,降低由于计算参数模糊性的影响带来边坡稳定性评价风险。     

基于模糊物元-综合集成赋权的工程评标模型

为了有效促进建筑工程项目科学合理评标,本文首先设计了工程项目评标指标的构成体系,又进一步针对现有评标决策方法的不足,提出了综合评价的观点,将模糊物元分析方法和综合集成赋权理论引入工程项目评标决策过程中,建立了基于模糊物元与综合集成赋权的评标模型,模糊物元分析充分考虑了评标中存在的不确定和模糊性问题,有效地避免了由于模糊性所导致的评标信息的丢失,综合集成赋权汲取了AHP赋权法与熵值法的优点,科学地界定了评价指标的权重,减少了多因素权重确定的随意性,最后通过实例分析表明,该模型有效地提高了评标效率,具有可操作性与适用性,为建筑工程项目的评标决策提供了重要的支撑。     

基于模糊综合评价法的房地产投资风险评价

从经济风险、社会风险、管理风险、环境风险四个方面建立了项目投资风险多层次评价指标体系。用层次分析法计算了各级指标的权重,运用了模糊综合评价方法对房地产项目投资进行风险评价,建立了模糊综合评价数学模型,提出一种基于模糊综合评价模型的定量化研究方法,并指出本模型能够综合评价开发项目的风险程度,对于预测开发项目风险程度具有较高的实用价值。     

基于模糊理论的路基边坡优化设计

根据相关规范在边坡普通模型基础上建立了边坡实用模糊优化模型，给出了求解该模糊优化模型的计算方法。结合具体工程实例显示了该模型和方法的优化效果，结果显示，基于模糊理论的优化方案更为优秀、合理。     

深基坑施工环境影响的模糊风险分析

 Based on fuzzy mathematics theory,a risk analysis model was established for the influence of deep excavation construction on surrounding environment. By using this model,reasonable risk loss evaluation index,risk grade division and risk loss formula were proposed through analytical and quantitative analysis of a concrete project example. After studying the evaluation index and relative weight of building damage,pavement damage and underground pipeline damage around the deep excavation,risk analysis and assessment of the influence on surrounding environment caused by excavation of foundation pit were achieved. The analysis and assessment is conducted through the membership degree which is given from the membership function structured for each evaluation factor. Then through the comprehensive risk evaluation,risk level can be finally determined. This result based on project example can be used as a reference for engineering decision-making.     

复杂双孔隧道施工安全稳定模糊数学分析及初步应用

基于模糊数学分析方法,建立了双孔复杂公路隧道模糊综合评价模型,确定了基本关联因素,并针对某一实际的公路复杂隧道安全施工及稳定性工程条件进行了模糊综合评价分析,结果表明该分析方法是可行的,可供实际及类似工程作为参考。     

Critical path effect based delay analysis method for construction projects

Assessing schedule delay's impact on total project duration to distribute delay liability remains a controversy. None of existing delay analysis methods is perfect because including an element of assumptions, subjective assessment and theoretical projection. Windows-based delay analysis methods are excellent in identifying and measuring construction schedule delays. Based on a previous study identifying potential problems in available windows-based delay analysis methods, this study proposes an innovative windows-based delay analysis method, called the effect-based delay analysis method (the EDAM method). The EDAM method performs delay analysis using extracted windows and determines delay impacts by considering the effects of delays on the critical path(s). According to its application to hypothetical cases and comparisons with other methods, the EDAM method is efficient in delay analysis and effective in solving concurrent delays and determining schedule shortened. The proposed EDAM method is a good alternative for schedule delay analysis for construction projects.     

基桩桩端岩溶顶板稳定性模糊能度 可靠性分析方法

 基于岩溶区基桩桩端岩溶顶板稳定性影响因素取值的随机性、模糊性以及区间性特征,首先,采用三角模糊数表示计算参数取值可能性分布,以此为基础建立出同时考虑抗冲切、抗剪与抗弯作用的桩端岩溶顶板稳定性模糊极限平衡分析模型;其次,综合运用模糊数学理论、岩体质量分类指标RMR以及Hoek-Brown经验强度准则建立计算参数三角模糊数确定方法,并运用截集技术与区间数运算规则计算相应的安全系数模糊集;再次,在探讨功能函数之合理确定方法基础上,采用模糊能度可靠性理论,提出基桩桩端岩溶顶板稳定性模糊能度可靠性分析方法;最后,通过工程实例分析表明该方法的合理性与可行性,其为基桩桩端岩溶顶板稳定性分析与评价提供了一种新的不确定性分析方法。     

基于模糊集理论的边坡稳定性分析

岩土工程中的各种信息都存在模糊性,通过对边坡稳定性分析中模糊因素的研究,提出了一种工程边坡模糊稳定性分析的新方法,建立了边坡稳定性分析的模糊数学模型,并给出了相应的求解方法。该模型可以考虑分析中所涉及到的计算力学参数的模糊性。在分析岩土力学参数试验资料的基础上,结合专家经验提出了岩土力学参数的隶属函数构造方法,利用统计资料构造了边坡稳定性评价的隶属函数,并提出了边坡稳定性评价的具体分类指标和模糊安全系数隶属度的计算方法。实例研究表明边坡稳定性模糊分析方法是一种更为合理的研究边坡稳定性的新方法。     

基于区间截断法的地下结构模糊能度可靠性模型研究

根据地下结构稳定性影响因素的随机性和模糊性特点,首先,引进三角模糊数理论,建立地下结构物理力学参数的可能性分布函数,然后,在地下结构稳定性评价之模糊可靠性功能函数确定方法研究基础上,引进区间截断法和区间数运算规则,建立了功能函数值域区间的确定方法,并避免了功能函数值域的扩展问题,最后,通过研究地下结构模糊能度可靠性度量方法,建立了地下结构模糊可靠性指标的可能性分布曲线及其失效可能度的确定方法,从而建立了地下结构模糊能度可靠性分析模型与方法。工程实例分析与计算结果表明了本文模型和方法的合理性与可行性。     

基于Z-number 改进挣值法的工程项目成本进度集成控制分析

挣值技术是项目实施中对项目进度费用进行评价与控制的重要工具。为提高挣值技术在不确定性环境中的适用性,引入Z-number 模糊数,运用α 截集法量化模糊数,提出一种新的模糊挣值模型。该模型不仅综合考虑了环境的模糊性、度量数据产生过程的不确定性及度量数据的可靠性,且能依据项目不同施工阶段特点,通过调节α 的取值控制环境的模糊性,从而更贴近工程项目不同施工阶段的实际情况。并从数据角度与传统模糊挣值模型进行对比,验明了模型在工程管理实践中具有更强的适应性和更精准的预测评价。     

基于模糊多属性群决策的工程交易模式选择研究

工程项目是国家进行实体投资的主要方式,而工程交易模式对工程项目能否成功实施起着决定性作用。为了使业主方能够选择出更加恰当的工程交易模式,文章对影响工程交易模式的影响因素进行了归纳总结,构建了工程交易模式决策指标体系。由于业主在进行工程交易模式选择时涉及的因素非常多且十分复杂,因此工程交易模式的选择是一个多属性的决策问题。文章通过运用熵权法及模糊多属性决策理论,建立了模糊多属性群决策模型,并用实例对该模型进行了验证,确保其有效性,最终为业主方提供了更加科学、合理、实用的工程交易模式的决策方法。     

AGGREGATING EXPERT OPINIONS BY FUZZY ENTROPY METHOD

This paper is a sequel to an earlier paper by the authors in which a model was developed for determining weights of criteria using a single expert's opinion. This paper further addresses the issue of aggregating individual expert opinions. A new technique, called fuzzy entropy method, is presented for aggregating expert opinions. In this study, the relative importance of expert opinions is scaled by fuzzy entropy, an entropy measure of the fuzzy information. The fuzzy entropy method is a combination of the conventional entropy method and the JHE method, a fuzzy information processing technique. One emphasis of the paper is placed on computational aspect of this new method. Examples are presented to demonstrate this method. Results of this study indicate that the fuzzy entropy method is a promising tool for aggregating expert opinions.