Schedule Risk Assessments Using a Precedence Network: An Object-Oriented Bayesian Approach
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RESEARCH PAPER
Schedule Risk Assessments Using a Precedence Network: An Object‑Oriented Bayesian Approach Kiazad Abbasnezhad1 · Ramin Ansari1 · Mahdi Mahdikhani1 Received: 30 June 2020 / Accepted: 11 November 2020 © Shiraz University 2020
Abstract Uncertainties affect the scheduling of construction projects. They are among the main causes of delays in construction projects, which increase project costs and reduce project quality. Uncertainties in scheduling affect the duration of activities. Under such conditions, the duration of each activity is influenced by several risk factors; however, previous Bayesian scheduling models considered the effects of one or no factor on the duration of tasks. Also, all parameters of the scheduling network were not considered in those models. In this study, given the causal relationships between uncertainties and their multiple effects on the task duration, a duration model is presented. Next, the effects of uncertainties on all scheduling parameters are applied to Bayesian object-oriented networks through mapping precedence networks. Object-oriented Bayesian networks are a new project management approach to risk assessment and uncertainties in decision-making. This approach is quite effective in considering the causal structure of risk variables and assessing the repetitive structure of precedence networks in large-scale scheduling networks. The project completion time, total slack, delays, as well as other scheduling parameters are estimated using the model proposed, which is titled the Bayesian Precedence Network. Keywords Risk assessment · Uncertainties · Project scheduling · Bayesian networks · Object-oriented
1 Introduction The uniqueness and timeliness of projects have made it difficult for project managers to decide (Khodakarami et al. 2007). From this perspective, limited data on all aspects of projects, especially in the early stages of planning, are available to the project team (Perry and Hayes 1985). Projects involve many uncertainties in scheduling (Eshtehardian and Khodaverdi 2016), quality (Fineman et al. 2009), costs (Khodakarami and Abdi 2014), and scope (Gardoni et al. 2007). The purpose of this study is to model scheduling uncertainties in projects. Out of the three major components of a project, scheduling is important because costs and * Ramin Ansari [email protected] Kiazad Abbasnezhad [email protected] Mahdi Mahdikhani [email protected] 1
Department of Civil Engineering, Faculty of Technical and Engineering, Imam Khomeini International University, Qazvin, Iran
resources are allocated to the project. One of the first steps in tendering is to prepare and define a schedule (Shafieezadeh et al. 2020). The lack of scheduling commensurate with adequate project conditions causes delays and even leads to construction projects (Chapman and Ward 2004). The average delay in construction projects in developing countries is 20–30% of the initial contract time (Eshtehardian and Khodaverdi 2016; Kim et al. 2009). According to researc
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