Project cash flow analysis in the presence of uncertainty in activity duration and cost

The inherent uncertainty and imprecision in project scheduling have motivated the proposal of several fuzzy set theory based extensions of activity network scheduling techniques. Building upon these, a cash flow calculation methodology for projects including activities with fuzzy durations and/or costs is proposed in this paper. According to the proposed approach, the project cash flow is represented by an S-surface (as opposed to the traditional S-curve) ensuing by connecting S-curves at different risk possibility levels. The methodology is exemplified by estimating the working capital requirements in a real world road construction project. Furthermore, the benefits of the methodology and its subsequent computerization are discussed. It is believed that the proposed approach may also be useful for both evaluating project proposals during feasibility studies and for performing earned value analysis for project monitoring and control.     

Queue performance measures in construction simulation models containing subjective uncertainty

In recent decades, discrete event simulation (DES) has been widely used for analyzing construction projects. Recently, fuzzy discrete event simulation (FDES), which is an integration of fuzzy set theory with DES, has been proposed for simulating construction projects. FDES provides a framework to consider subjective uncertainty (uncertainty due to vagueness, subjectivity, and linguistic expression of knowledge) in construction simulation models. Current FDES frameworks only calculate simulation time (e.g., project completion time) as the simulation output. However, queue performance measures (e.g., average queue length and waiting time)—though important simulation model outputs for decision making, finding bottlenecks, and optimizing construction resources—are not analyzed in current FDES methodologies. Using fuzzy logic to consider the subjective uncertainty of service time and the inter-arrival time of systems' queues may improve such simulation models by more realistically representing their results. This paper provides a novel methodology to consider subjective uncertainty in analyzing the fuzzy queues in construction FDES models. Incorporating fuzzy queuing theory with FDES methodology as proposed in this paper enhances the applicability of FDES in construction projects. The proposed methodology is validated through mathematically solved queueing examples, and its practical aspects are illustrated using an example of an asphalt paving operation.     

CONTROL OF CONSTRUCTION ACTIVITIES: III. FUZZY-BASED CONTROLLER

In this paper, a real-time fuzzy-based controller of construction activities is proposed. Because of the numerous uncertainties associated with construction activities, their control requires a different approach than the traditional feedback methods. These methods are essentially based on the knowledge of a transfer function that models the input/output relationships for the controlled system. For a highly complex and uncertain system such as a construction activity, a fuzzy-based control strategy was found to be a suitable and effective approach. The proposed control system is built in two main levels, the process and the activity levels. Each level comprises two main units, namely, the fuzzy controller and the self learning algorithm. The implementation of the control actions can be performed by either manipulating the states of the variables for the purpose of improving the process output, or changing the process behavior function for the same purpose. Practical examples are presented wherever possible to illustrate the proposed control strategy.     

The STEPS approach: A realistic method to design and construct underground facilities

The underground industry remains an important part of the construction industry, but suffers from numerous real and perceived problems. One of the most serious problems-the level of risk and uncertainty in scope, schedule, and budget-is a dramatic example of how real and perceived issues can become blurred, and thereby inhibit the implementation of good solutions. This paper defines some important ramifications of the risk and uncertainty issues, further documenting how they can adversely affect specific projects and the industry ingeneral. The causes of this partiular problem are listed in sufficient detail to suggest possible avenues for constructive changes in our management of risk. One of the causes that gets disicussed only reluctantly is the unwillingness (for a variety of reaons) to FULLY discuss ALL sources of uncertainty early in the project planning process. The paper also presents a general discussion of an approach to mitigate the adverse effects of uncertainty and risk using different assumed levels of client involvement, and flexble. The STEPS Approach is very flexible, but requires a major shift in emphasis regarding the appropriate level and detail of coordination and communication for project participants. Key aspects of the approach are provided, along with a set of recommendations that will aid its implementation.     

Payment for offsite goods and materials: the Scottish perspective*

Materials are a critical element within the construction industry yet- the conditions and legality surrounding their ownership remains an area of uncertainty. The difficulty in ascertaining ownership is often found in the instances of payment, delivery and complex contractual relationships. Additionally, the nature of the construction industry whereby raw materials are purchased within a supply chain and are incorporated into the fabric of buildings or goods often creates further confusion. The importance of ownership is most apparent in the instance of disputes or insolvencies, both of which are regular occurrences within the construction industry and in the management of a project regarding cash flow and programme. To inform the position and stance of Scots Law in relation to ownership of materials it is necessary to evaluate current law regarding ownership of materials in Scotland through the undertaking of a literature review which establishes the prevailing legal structure. Conclusions and recommendations propose that parties of a construction contract, for which Scots Law is applicable, are aware of current law surrounding the intricate matter regarding ownership of materials in Scots Law     

Towards quantification of uncertainty in predicting water quality failures in integrated catchment model studies

This paper describes the development and application of a method for estimating uncertainty in the prediction of sewer flow quantity and quality and how this may impact on the prediction of water quality failures in integrated catchment modelling (ICM) studies. The method is generic and readily adaptable for use with different flow quality prediction models that are used in ICM studies. Use is made of the elicitation concept, whereby expert knowledge combined with a limited amount of data are translated into probability distributions describing the level of uncertainty of various input and model variables. This type of approach can be used even if little or no site specific data is available. Integrated catchment modelling studies often use complex deterministic models. To apply the results of elicitation in a case study, a computational reduction method has been developed in order to determine levels of uncertainty in model outputs with a reasonably practical level of computational effort. This approach was applied to determine the level of uncertainty in the number of water quality failures predicted by an ICM study, due to uncertainty associated with input and model parameters of the urban drainage model component of the ICM. For a small case study catchment in the UK, it was shown that the predicted number of water quality failures in the receiving water could vary by around 45% of the number predicted without consideration of model uncertainty for dissolved oxygen and around 32% for unionised ammonia. It was concluded that the potential overall levels of uncertainty in the ICM outputs could be significant. Any solutions designed using modelling approaches that do not consider uncertainty associated with model input and model parameters may be significantly over-dimensioned or under-dimensioned. With changing external inputs, such as rainfall and river flows due to climate change, better accounting for uncertainty is required.     

基于VISAM模型的施工动态仿真建模方法研究

施工动态仿真的复杂建模过程限制了其在工程领域得到推广并作为辅助管理决策的有效手段.提出了一种新的仿真建模方法,采用真实施工场景下交互式仿真智能体模型来构建仿真系统,在真实施工场景下创建实体模型,设置仿真属性,建立智能体规则库,构建仿真模型拓扑关系,并在高度沉浸感的环境下进行交互式仿真控制,简化了仿真建模过程,提高了施工仿真的直观性和可接受性.     

Schedule risk analysis of infrastructure projects: A hybrid dynamic approach

Schedule risk is a major concern in infrastructure project management. Existing studies have proposed several models for schedule risk analysis, but few efforts have been made on the dynamics and uncertainty of risks and the generality and practicability of the model. To fill the research gaps, this study develops a hybrid dynamic approach for investigating the effect of risks on infrastructure project schedule performance. This approach combines system dynamics (SD) and discrete event simulation (DES) which have mainly been used to analyze the macroscopic and microcosmic construction issues in isolation, respectively. The model is then verified by data which is collected from a bridge construction project. As an application example, the effect of four selected risks on the schedule was explored. The results show that the proposed SD-DES model could be ease of modifying the model to reflect real situation, performing various sensitivity and uncertainty analysis, and showing simulation results more effectively.     

Strategic change towards cost-efficient public construction projects

The cost of public construction projects is a central topic in project management. However, studies have primarily focused on cost at the project level, not on cost management at the portfolio level. In this paper, we take the perspective of a government agency, conducting a strategic initiative to increase cost-efficiency in their portfolio of construction projects. We use an action research approach to investigate the dynamics of the initiative and the implementation of resulting actions to achieve lasting change towards cost-efficiency. Co-creating actions for cost-efficiency together with the project teams was important for the success of the strategic initiative. For successful implementation, alignment of the objectives of the initiative with organizational strategy, and knowledge transfer between projects is central. This study expands the project management literature regarding strategic cost management of portfolios of construction projects and provides practical guidance for organizations.     

A Probabilistic Framework for Bayesian Adaptive Forecasting of Project Progress

Abstract:   A methodology to forecast project progress and final time-to-completion is developed. An adaptive Bayesian updating method is used to assess the unknown model parameters based on recorded data and pertinent prior information. Recorded data can include equality, upper bound, and lower bound data. The proposed approach properly accounts for all the prevailing uncertainties, including model errors arising from an inaccurate model form or missing variables, measurement errors, statistical uncertainty, and volitional uncertainty .
As an illustration of the proposed approach, the project progress and final time-to-completion of an example project are forecasted. For this illustration construction of civilian nuclear power plants in the United States is considered. This application considers two cases (1) no information is available prior to observing the actual progress data of a specified plant and (2) the construction progress of eight other nuclear power plants is available. The example shows that an informative prior is important to make accurate predictions when only a few records are available. This is also the time when forecasts are most valuable to the project manager. Having or not having prior information does not have any practical effect on the forecast when progress on a significant portion of the project has been recorded .     

Assessing reliability of design,construction, and safety related decisions

Currently there is no approach which would help to comprehensively ensure occupational safety. Many scientists perform researches and calculations, create new methods related to safety and health, but most of them analyze separate aspects of safety in the field of construction. The authors of this paper present a new complex view on ensuring occupational safety and health during construction. The selection of safety solutions is performed based on complex evaluation of structure, technology and safety. In their previous works, the authors offered a new method for multiple attribute decision synthesis, SyMAD-3, which helps to choose an effective construction project alternative from multiple alternatives by assessing various construction, technological and occupational safety solutions, based on a set of quantitative attributes. However, the integration of these solutions may cause doubts, since decision making in construction is always associated with uncertainty. The investment projects in construction are characterized by the large accuracy variation (from 15 to 50%) of some attribute values. Although the SyMAD-3 method is mathematically grounded, it does not answer the question if the error of attribute values impacts the final decision and if this decision can be reliably assessed.In the present paper, the authors supplement the SyMAD-3 method with decision sensitivity analysis (SyMAD-3 with SA) to improve the reliability of the SyMAD-3 method and assess the reliability of the obtained decision. The SyMAD-3 with SA method allows us to choose an effective alternative of a construction project by assessing three stages of construction, based on a set of attributes given the error of their values, and determine the reliability of the final decision. The proposed method is implemented in a software package created by the authors with the aim of analyzing decisions and performing experimental calculations in the field of construction.     

How do project management competencies change within the project management career model in large Chinese construction companies?

Due to the increasing complexity and flexibility of business activities, project-based organizations have become common. In such organizations, project management competencies, which refer to a collection of knowledge, personal attitudes, skills, and relevant experience, are core assets that must be taken seriously. Formalized project management career paths have been widely implemented in the construction industry. However, most recent studies treat project management competencies as static constructs and fail to consider their dynamic changes as a career path advances. To fill this gap in the literature, this study conducted an empirical examination of project management competencies integrated with a career model for the construction industry. First, key project management competencies are identified through a literature review. Then, a project management career model for large Chinese construction companies is developed based on an empirical investigation of six large Chinese construction companies from various sectors. Moreover, a quantitative analysis is performed to explore how these competencies dynamically change as position levels rise in the career model. The research findings indicate that significant differences in project management competencies exist at different levels of the career model. However, the distribution remains steady at different project management position levels for conceptual and organizational competencies, human competencies, and technical competencies.     

Dynamic modeling of the quantitative risk allocation in construction projects

Allocation of construction risks between owners and their contractors has a significant impact on the total construction costs. This research presents an integrated fuzzy-system dynamics approach for quantitative risk allocation. All the factors affecting the risk allocation process are modeled using system dynamics approach. Fuzzy logic is integrated into system dynamics modeling structure to account for the existing uncertainties. The values of different factors that have an uncertain nature are determined by fuzzy numbers. The application of Zadeh's extension principle and interval arithmetic is proposed for the system dynamics to enable the system outcomes to be presented considering uncertainties in the input variables. Using the proposed integrated fuzzy-SD model, the project cost is simulated at different percentages of risk allocation. The optimum percentage of risk allocation is determined as a point in which the project cost is minimized. The performance of the proposed method is assessed by employing the method in a tunneling project.     

Conceptual determinants of construction project management competence: A Chinese perspective

In recent years Western project management theories and practices have become increasingly recognized and dispersed in China, particularly in construction-related work. The assessment and development of project management competence in China are driven by attempts to follow the Western standards-based competence certification programmes. Yet little is known about whether and how the predefined set of knowledge embodied in the Western standards are used by Chinese project managers in their workplace. In this paper we report an empirical exploration of Chinese construction project managers’ ways of conceiving and accomplishing their work. We replicate in the Chinese context the previous UK-based phenomenographic study of construction project management competence, which revealed three different conceptions arranged in a hierarchy of performance. The results of this China-based study confirm the conceptual determinants of construction project management competence first revealed in the UK, and provide practical implications for effective training and professional certification of project management competence in China. Meanwhile, the replication of the phenomenographic approach to understanding project management competence in China enhances the cross-cultural validity of the approach and highlights its potential for explorative management research.     

Managing construction project change: a knowledge management perspective

In the information age, organization theories have addressed problem‐solving as an information‐processing activity. However, in this era, with the realization of knowledge‐based views of the organization, shared problem‐solving is increasingly recognized as a knowledge creation trigger. During shared problem‐solving, stakeholders bring different types of knowledge into the problem situation and it is captured, created and shared by the team members. In construction projects, shared problem‐solving often takes place through pragmatic problem‐solving on site, in particular, through managing project changes. However, this significant role of knowledge in managing project change is not well appreciated in the extant literature. Accordingly, to explore how knowledge is created during project changes in construction a case study approach was adopted using two change events in two collaborative settings within the UK construction industry. The case study findings revealed that different forms of knowledge are created during the project change process within construction projects. However, this knowledge remains largely tacit and does not disseminate to the wider organization due to imbalanced codification and personalization strategies existing in such settings. A knowledge management perspective is introduced to manage project change so that construction project teams can successfully resolve and learn from change events.     

基于FUZZY-AHP的建设项目风险评价研究

指出建设项目所面临的不确定性在增加,项目风险在不同程度地加大,使得参与各方必须具备项目风险识别及评价的能力,运用模糊数学和层次分析法的相关知识,建立了建设项目风险评价的指标体系和数学模型,以实现风险评价的定量化。     

Coping with uncertainty: Knowledge sharing in new product development projects

The automotive industry is a leader in the use of design agents to create components for new and redesigned vehicles. In the resulting interorganizational relationship, uncertainties at project inception add to the difficulty of delivering new component designs and force knowledge transference to comply with requirements as the project progresses. Organizational Information Processing Theory drives a research framework to examine the levels of knowledge exchange appropriate under prevailing uncertainty. A survey of over 300 design agencies validates the framework. Results show non-linear relationships with both positive and negative aspects of knowledge exchange that vary according to the levels of uncertainty, knowledge requirements, and exchange capacity. Theoretical implications include confirming mediated impacts of uncertainty and structured communication on project productivity plus the addition of precise alignment of knowledge requirements and knowledge exchanges. Design agencies must secure adequate, but not excessive, knowledge exchange. Researchers may consider the framework as a basis for extending the effect of uncertainty on consequential performance, as opposed to assuming uncertainty will impede effectiveness or testing uncertainty and managerial interventions as separate contingencies. Managers must work to carefully identify knowledge requirements at project commencement and establish appropriate communication structures and practices.     

Selection of slab formwork system using fuzzy logic

Formwork plays an important role in building construction. The selection of an appropriate formwork system can reduce project cost, improve quality and speed up the construction process. Although the selection of an appropriate formwork system requires years of experience in formwork design, few experienced personnel may be available, especially in small/medium size contracting companies. With the lack of such experts, the costly outsourcing option becomes essential otherwise the selection of a particular formwork system might not be appropriate. A structured approach is developed to help decision makers in small/medium Egyptian construction companies to select the appropriate horizontal formwork system(s) for their projects. This can be achieved by recognizing the project governing factors affecting the selection process. Based on these factors, a knowledge base is developed to facilitate the process. A fuzzy logic system is used to automate the process and overcome ambiguity and uncertainty in the selection process. The system is shown to be useful and accurate in its application to a real-life case. A survey of formwork experts reveals its ease of use. Further research will expand the system to consider vertical formwork selection to ensure full compatibility.     

基于生态建设的设计施工互动协作管理模式研究与应用

寻求传统模式下(设计与施工分离)现实可行的设计与施工的沟通合作方式,是当前工程项目管理中急需解决的一个课题.生态建设的考虑对建筑工程建设提出了更多、更高的要求,需要设计和施工单位更多的交流和互动.以某工程项目为依托,提出了基于生态建设的设计施工互动协作管理模式,阐述了模式内涵,并对项目管理中的应用结果进行了简要总结和探...     

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。