A Petri net based method for the early verification & validation of a simulation study in construction management

A simulation study in construction management is business information that supports decision-making activities in construction planning and scheduling. To be confident in the various results of a simulation study, it is intuitive to be confident first in the collected simulation model inputs. This paper proposes properties to verify and validate simulation model inputs. The proposed V&V (Verification and Validation) properties are registered in a method that navigates an automatically generated project network. The project network is modeled as a marked graph Petri net. The method inspects the Petri net’s transitions and collects the needed information according to the properties. The validity of the method is confirmed by an in-house building construction project where errors and semantic mistakes in the building project’s model inputs were detected. PROBLEM DESCRIPTION AND SOLUTION Building construction projects are complex because of the unique characteristics of each new building facility in addition to the corresponding unique surrounding construction conditions. The use of simulation in construction management allows decision-makers to analyze the project unique and dynamic processes rather than to guess the project schedule based on experience. This results in examining different resource allocation strategies and in highlighting the risks of various project schedule alternatives before starting the real execution of the building project. After gathering the required simulation model inputs, these inputs will be executed by a simulation environment. Based on the project’s objectives, a large number of possible project schedule alternatives will be generated (Samkari et al. 2012). The project’s objective is to increase the utilization of the production resources with respect to the contract’s absolute and relative deadlines, while decreasing both the project’s makespan and costs. However, to what extent can decision-makers be confident in those simulation results and thus remain in control of the decision-making process? It is intuitive that the completeness and correctness of the simulation results are realized only if the completeness and correctness of the simulation model inputs are confirmed regardless of how rich the model is (Bengtsson et al. 2009). Generally, the simulation results are represented as Gantt diagrams that are time schedules, and as computer animations after linking the 3D-CAD (computer-aided design) objects with construction activities of a time schedule. Those representations assist in principle the decision support process in finding the best time schedule (simulation result). In contrast, these representations and diagrams do not aim and are not designed to detect errors in the time schedule caused by errors in the simulation model inputs. In order to enable building construction practitioners to use simulation effectively in their business, simulation model inputs must be verified and validated first. The authors defined several V&V properties 978-1-4673-4781-5/12/$31.00 ©2012 IEEE