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Article

Farnad Nasirzadeh, H.M. Dipu Kabir, Mahmood Akbari, Abbas Khosravi, Saeid Nahavandi and David G. Carmichael

This study aims to propose the adoption of artificial neural network (ANN)-based prediction intervals (PIs) to give more reliable prediction of labour productivity using…

Abstract

Purpose

This study aims to propose the adoption of artificial neural network (ANN)-based prediction intervals (PIs) to give more reliable prediction of labour productivity using historical data.

Design/methodology/approach

Using the proposed PI method, various sources of uncertainty affecting predictions can be accounted for, and a PI is proposed instead of a less reliable single-point estimate. The proposed PI consists of a lower and upper bound in which the realization of the predicted variable, namely, labour productivity, is anticipated to fall with a defined probability and represented in terms of a confidence level (CL).

Findings

The proposed PI method is implemented on a case study project to predict labour productivity. The quality of the generated PIs for the labour productivity is investigated at three confidence levels. The results show that the proposed method can predict the value of labour productivity efficiently.

Practical implications

This study is the first attempt in construction management to undertake a shift from deterministic point predictions to interval forecasts to improve the reliability of predictions. The proposed PI method will help project managers obtain accurate and credible predictions of labour productivity using historical data. With a better understanding of future outcomes, project managers can adopt appropriate improvement strategies to enhance labour productivity before commencing a project.

Originality/value

Point predictions provided by traditional deterministic ANN-based forecasting methodologies may be unreliable due to the different sources of uncertainty affecting predictions. The current study proposes ANN-based PIs as an alternative and robust tool to give a more reliable prediction of labour productivity using historical data. Using the proposed method, various sources of uncertainty affecting the predictions are accounted for, and a PI is proposed instead of a less reliable single point estimate.

Details

Engineering, Construction and Architectural Management, vol. 27 no. 9
Type: Research Article
ISSN: 0969-9988

Keywords

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Article

Morteza Bayat, Mostafa Khanzadi, Farnad Nasirzadeh and Ali Chavoshian

This study aims to determine the optimal value of concession period length in combination with capital structure in build–operate–transfer (BOT) contracts, based on direct…

Abstract

Purpose

This study aims to determine the optimal value of concession period length in combination with capital structure in build–operate–transfer (BOT) contracts, based on direct negotiation procurement and considering the conflicting financial interests of different parties involved in the project.

Design/methodology/approach

The financial model of a BOT project is developed considering all the influencing factors. Then, fuzzy set theory is used to take into account the existing risks and uncertainties. Bilateral bargaining game based on alternating-offers protocol is applied between the government and the sponsor to divide project financial benefit considering the lender’s requirements. Finally, concession period and equity level will be determined simultaneously according to the sponsor’s and government’s share of project financial benefit and the lender’s requirements.

Findings

The proposed model is implemented on a real case study, and a fair and efficient agreement on concession period length and capital structure is achieved between the government and the sponsor considering the lender’s requirements. It is revealed that being the first proposer in the bargaining process will affect the concession period length; however, it will not affect the equity level. Moreover, it is shown that considering income tax as a part of government’s financial benefit increases the length of concession period.

Research limitations/implications

The presented model concentrates on direct negotiation procurement in BOT projects where the sponsor and government bargain on dividing financial benefits of project. It is assumed that the product/service price is determined before according to market analysis or users’ affordability. All the revenue of project during concession period is assumed to belong to the sponsor.

Practical implications

The proposed model provides a practical tool to aid BOT participants to reach a fair and efficient agreement on concession period and capital structure. This could prevent failing or prolonging the negotiation and costly renegotiation.

Originality/value

By investigation of previous studies, it is revealed that none of them can determine the optimal value of concession period length and capital structure simultaneously considering the BOT negotiation process and different financial interests of parties involved in the project. The proposed model presents a new approach to determine the financial variables considering the conflicting interests of involved parties. The other novelty aspects of the presented model are as follows: introducing a new approach for calculating the sponsor and the government’s share of project financial benefit that will affect the determination of the concession period length and considering the effect of existing risks and uncertainties on final agreement between the involved parties using fuzzy set theory.

Details

Construction Innovation , vol. 20 no. 1
Type: Research Article
ISSN: 1471-4175

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Article

Shahab Shoar, Farnad Nasirzadeh and Hamid Reza Zarandi

The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both…

Abstract

Purpose

The purpose of this paper is to present a fault tree (FT)-based approach for quantitative risk analysis in the construction industry that can take into account both objective and subjective uncertainties.

Design/methodology/approach

In this research, the identified basic events (BEs) are first categorized based on the availability of historical data into probabilistic and possibilistic. The probabilistic and possibilistic events are represented by probability distributions and fuzzy numbers, respectively. Hybrid uncertainty analysis is then performed through a combination of Monte Carlo simulation and fuzzy set theory. The probability of occurrence of the top event is finally calculated using the proposed FT-based hybrid uncertainty analysis method.

Findings

The efficiency of the proposed method is demonstrated by implementing in a real steel structure project. A quantitative risk assessment is performed for weld cracks, taking into account of both types of uncertainties. An importance analysis is finally performed to evaluate the contribution of each BE to the probability of occurrence of weld cracks and adopt appropriate response strategies.

Research limitations/implications

In this research, the impact of objective (aleatory) dependence between the occurrences of different BEs and subjective (epistemic) dependence between estimates of the epistemically uncertain probabilities of some BEs are not considered. Moreover, there exist limitations to the application of fuzzy set rules, which were used for aggregating experts’ opinions and ranking purposes of the BEs in the FT model. These limitations can be investigated through further research.

Originality/value

It is believed that the proposed hybrid uncertainty analysis method presents a robust and powerful tool for quantitative risk analysis, as both types of uncertainties are taken into account appropriately.

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Article

Farnad Nasirzadeh, David G. Carmichael, Mohammad Jafar Jarban and Mozhdeh Rostamnezhad

The purpose of this paper is to present a novel hybrid fuzzy-system dynamics (SD) approach for the quantification of the impacts of construction claims.

Abstract

Purpose

The purpose of this paper is to present a novel hybrid fuzzy-system dynamics (SD) approach for the quantification of the impacts of construction claims.

Design/methodology/approach

The most significant claims affecting a project are identified. The various factors affecting the impacts of claims are identified. Then, the qualitative model of construction claims is constructed considering the complex inter-related structure of the influencing factors. The mathematical relationships among the variables are determined and the quantitative model of claims is built. Finally, fuzzy logic is integrated into the proposed model to take into account the existing uncertainties.

Findings

To show the capabilities of the proposed simulation model, it is implemented on a real project and the impacts of the identified claims on the project cost are quantified. It is shown that the external interactions among different claims can intensify their overall impact.

Research limitations/implications

Identification of interactions among various influencing factors is not an easy job when there are a large number of claims in a project. Well-qualified experts and the existence of historical data may limit the application of the proposed method in projects with limited data and/or qualified experts.

Practical implications

The proposed hybrid fuzzy-SD approach provides a practical and flexible tool that can be used in various construction projects to assess the cost impacts of construction claims taking into account their complex interactions. Using the proposed method, the accuracy of achieved results is increased compared to conventional methods that are used for the quantification of claims since the complex inter-related structure of influencing factors and the claims interactions are taken into account. One of the capabilities of the proposed hybrid fuzzy-SD method is its flexibility. Depending on the type of contract and the parties involved in the project, the proposed hybrid fuzzy-SD method can be used during different stages of the project life cycle to model and quantify claims.

Originality/value

The proposed approach may present a flexible and robust method for quantification of construction claims. The novelty aspects of this paper are as follows: the extensively complex structure of claims arising from both internal and external interactions is accounted for using SD. The existing uncertainties affecting the impacts of a claim are taken into account.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 7
Type: Research Article
ISSN: 0969-9988

Keywords

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Article

Hadi Mahami, Farnad Nasirzadeh, Ali Hosseininaveh Ahmadabadian, Farid Esmaeili and Saeid Nahavandi

This paper aims to propose an automatic imaging network design to improve the efficiency and accuracy of automated construction progress monitoring. The proposed method…

Abstract

Purpose

This paper aims to propose an automatic imaging network design to improve the efficiency and accuracy of automated construction progress monitoring. The proposed method will address two shortcomings of the previous studies, including the large number of captured images required and the incompleteness and inaccuracy of generated as-built models.

Design/methodology/approach

Using the proposed method, the number of required images is minimized in two stages. In the first stage, the manual photogrammetric network design is used to decrease the number of camera stations considering proper constraints. Then the image acquisition is done and the captured images are used to generate 3D points cloud model. In the second stage, a new software for automatic imaging network design is developed and used to cluster and select the optimal images automatically, using the existing dense points cloud model generated before, and the final optimum camera stations are determined. Therefore, the automated progress monitoring can be done by imaging at the selected camera stations to produce periodic progress reports.

Findings

The achieved results show that using the proposed manual and automatic imaging network design methods, the number of required images is decreased by 65 and 75 per cent, respectively. Moreover, the accuracy and completeness of points cloud reconstruction is improved and the quantity of performed work is determined with the accuracy, which is close to 100 per cent.

Practical implications

It is believed that the proposed method may present a novel and robust tool for automated progress monitoring using unmanned aerial vehicles and based on photogrammetry and computer vision techniques. Using the proposed method, the number of required images is minimized, and the accuracy and completeness of points cloud reconstruction is improved.

Originality/value

To generate the points cloud reconstruction based on close-range photogrammetry principles, more than hundreds of images must be captured and processed, which is time-consuming and labor-intensive. There has been no previous study to reduce the large number of required captured images. Moreover, lack of images in some areas leads to an incomplete or inaccurate model. This research resolves the mentioned shortcomings.

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Article

Mostafa Khanzadi, Farnad Nasirzadeh, Mostafa Mir and Pouya Nojedehi

The purpose of this paper is to present a hybrid simulation approach for predicting the value of labor productivity taking account of various continuous influencing…

Abstract

Purpose

The purpose of this paper is to present a hybrid simulation approach for predicting the value of labor productivity taking account of various continuous influencing factors and the interactions between different agents involved in the project.

Design/methodology/approach

The various continuous factors affecting labor productivity are simulated using system dynamics (SD). The heterogeneity of different agents involved in the project and their interactions is accounted using agent-based modelling (ABM). The developed ABM and SD models are finally integrated to simulate the value of labor productivity taking account of all the influencing factors.

Findings

The proposed hybrid simulation tool is implemented in a real project to evaluate its perfomance. The value of labor productivity is simulated by taking account of all the influencing factors. The most appropriate execution strategy is then selected using the developed hybrid SD-ABM approach to improve productivity. It is shown that the number of working groups and their movement patterns affect the severity of the groups’ interferences which will in turn affect the value of labor productivity.

Practical implications

This research helps project managers to predict and improve the value of labor productivity taking account of all the influencing factors.

Originality/value

It is believed that the proposed hybrid SD-ABM simulation approach offers a novel and robust tool for modeling labor productivity because the effects of various continuous influencing factors and the interactions between different agents are taken into account through the combination of SD and ABM. Many complex problems faced in construction projects involve interacting elements of a different nature, and the integration of SD with ideas from ABM offers potential to combine the strengths of the two methodologies to solve the problem.

Details

Construction Innovation, vol. 18 no. 1
Type: Research Article
ISSN: 1471-4175

Keywords

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Article

Mozhdeh Rostamnezhad, Farnad Nasirzadeh, Mostafa Khanzadi, Mohammad Jafar Jarban and Masoud Ghayoumian

This research aims to model the social dimension of sustainability in construction projects. A new hybrid system dynamic (SD)–fuzzy Decision-Making Trial and Evaluation…

Abstract

Purpose

This research aims to model the social dimension of sustainability in construction projects. A new hybrid system dynamic (SD)–fuzzy Decision-Making Trial and Evaluation Laboratory (DEMATEL) method is proposed to analyze the various factors affecting social aspect of sustainability taking into account their complex interactions.

Design/methodology/approach

The various factors affecting the social dimension of sustainable development are identified based on the opinions of 12 experts with an extensive experience in highway construction projects and a thorough knowledge and/or professional experience in the sustainability area. The qualitative model of social sustainability is constructed using SD approach and the complex inter-related structure of the various influencing factors are modeled using cause and effect feedback loops. Fuzzy set theory is applied to model the uncertainty of human judgments. The importance of various influencing factors is then determined quantitatively taking account of their complex interactions using the proposed SD-fuzzy DEMATEL method. The most significant influencing factors are finally determined.

Findings

To evaluate the performance of the proposed method, it is implemented on a real highway project and the importance of various factors affecting the social sustainability is determined. A set of complex interrelated factors affecting social sustainability are divided into cause and effect groups, and the root causes affecting the social sustainability performance of the project are determined. Therefore, the required managerial actions can be taken to improve the social sustainability.

Research limitations/implications

Well-qualified experts with a well-developed mental model of social sustainability are necessary to provide required input data for modeling social sustainability using the proposed approach. The absence of such experts could be a limitation for the implementation of the proposed model on a new project.

Practical implications

The proposed Hybrid SD-fuzzy DEMATEL method provides a practical and robust tool to analyze the various factors affecting social sustainability taking into account their complex interactions.

Originality/value

The proposed method offers a more precise and accurate analysis of various factors affecting social sustainability of construction projects since the complex inter-related structure of influencing factors as well as the vague and imprecise nature of experts' judgment is taken into account efficiently.

Details

Engineering, Construction and Architectural Management, vol. 27 no. 7
Type: Research Article
ISSN: 0969-9988

Keywords

Content available
Article

Behzad Mahjoubpour, Farnad Nasirzadeh, Mahmoud Mohammad Hosein Zadeh Golabchi, Maryam Ramezani Khajehghiasi and Mostafa Mir

Learning as the way in which labor acquire new knowledge and skills has important strategic implications for the competitive advantage of an organization. The purpose of…

Abstract

Purpose

Learning as the way in which labor acquire new knowledge and skills has important strategic implications for the competitive advantage of an organization. The purpose of this paper is to present an agent-based modeling (ABM) approach to investigate the learning behavior of workers. The effect of interactions among different workers as well as the factors affecting the workers’ learning behavior is assessed using the proposed ABM approach.

Design/methodology/approach

For this purpose, the processes through which the competency value of worker is changed are understood and the workers’ learning behavior is modeled, taking account of various influencing factors such as knowledge flow, social ability to teach and forgetting factor.

Findings

The proposed model is implemented on a real steel structure project to evaluate its applicability and performance. The variation in the competency value of different workers involved in the project is simulated over time taking account of all the influencing factors using the proposed ABM approach.

Practical implications

In order to assess the effect of interactions among welders as well as the welders’ characteristics on their learning behavior, the competence value of different welders is evaluated.

Originality/value

This research presents an ABM approach to investigate the workers’ learning behavior. To evaluate the performance of the proposed ABM approach, it was implemented on a real steel structure project. The learning behavior of different welders (agents) was simulated taking account of their interactions as well as the factors affecting the welders’ learning behavior. The project involved the welding of a 240-ton steel structure. The initial project duration was estimated as 100 days. In this project, it has been planned to execute the welding process using three different welders namely welder A, B and C.

Details

Engineering, Construction and Architectural Management, vol. 25 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

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Article

Saeed Moradi, Farnad Nasirzadeh and Farzaneh Golkhoo

The purpose of this research is to propose a hybrid simulation framework which can take into account both the continuous and operational variables affecting the…

Abstract

Purpose

The purpose of this research is to propose a hybrid simulation framework which can take into account both the continuous and operational variables affecting the performance of construction projects.

Design/methodology/approach

System dynamics (SD) simulation paradigm is implemented for the modelling of the complex inter-related structure of continuous variables and discrete event simulation (DES) is implemented for the modelling of operational influencing factors. A hybrid modelling framework is then proposed through combination of SD and DES to simulate the construction projects.

Findings

This paper discusses the deficiencies of two traditional simulation methods – SD and DES – for simulation of construction projects which can be compensated by implementing hybrid SD–DES model. Different types of basic hybrid structures and synchronisation methods of SD and DES models are introduced.

Practical implications

The proposed hybrid framework discussed in this research will be beneficial to modellers to simulate construction projects.

Originality/value

The paper introduces a theoretical framework for a hybrid continuous- discrete simulation approach which can take into account the dynamics of project environment arising from the complex inter-related structure of various continuous influencing factors as well as the construction operations. Different steps required to develop the hybrid SD–DES model and synchronisation of SD and DES simulation methods are illustrated.

Details

Construction Innovation, vol. 15 no. 1
Type: Research Article
ISSN: 1471-4175

Keywords

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