Assessment of global sensitivity analysis methods for project scheduling

Product development requires scheduling that considers the interdependence between activities. The definition of the interdependencies and duration of activities, communication times and the level of overlap between activities is needed for project scheduling. However, these parameters have epistemic uncertainties that can affect project scheduling. In this work, different global sensitivity analysis techniques were applied to identify the parameters that had the greatest effect on project scheduling. It was concluded that standardized regression coefficients as well as the Morris and Sobol Jansen methods were the most appropriate. It was also found that global sensitivity analysis can help to focus resources based on the definitions and control the uncertainty of key activities. Furthermore, it was concluded that control of the uncertainty of key activities reduces the uncertainty and duration of projects.Galvez, ED.; Capuz-Rizo, SF. (2016). Assessment of global sensitivity analysis methods for project scheduling. Computers and Industrial Engineering. 93:110-120. doi:10.1016/j.cie.2015.12.010S1101209

Evaluation of Project Duration Uncertainty using the Dependency Structure Matrix and Monte Carlo Simulations

The sequence of tasks is vital to the development of any project. The order of tasks is influenced by the information flow among them. The dependency structure matrix (DSM) can be used to model information flow. However, the information used by the DSM, including task duration, time required for communication, and task overlap, can have uncertain values. The aim of this paper is to analyze the effect of uncertainty on the scheduling of tasks using the DSM. Monte Carlo Simulation is applied to represent uncertainty in time estimates for projects using DSM. Conventional project duration, normal project duration with communication times, and normal project duration containing natural overlapping were considered for project time estimations. Several distribution functions were used to represent the uncertainty. It is concluded that project duration has normal distribution behavior that is independent of the type of input parameter distribution functions; that mean values of the input parameters give a good estimation of mean project duration; that interval and inner interval arithmetic give overestimation and underestimation of project duration times respectively.La secuencia de actividades es vital para el desarrollo de cualquier proyecto. El orden de las actividades está influenciado por el flujo de información entre ellas. La matriz de la estructura de dependencias (DSM) se puede utilizar para modelar el flujo de información. Sin embargo, la información utilizada por la DSM puede tener valores inciertos. El objetivo de este trabajo es analizar el efecto de la incertidumbre sobre la programación de actividades utilizando la DSM. La simulación de Monte Carlo se aplica para representar la incertidumbre en las estimaciones de tiempo para proyectos que utilizan DSM. Para las estimaciones de duración de proyecto se consideraron la duración convencional del proyecto, la duración normal de proyecto con tiempos de comunicación, y la duración normal de proyecto con superposición natural. Las incertidumbres se representaron con varias funciones de distribución. Se concluye que la duración de proyecto presenta distribución normal que es independiente del tipo de funciones de distribución de los parámetros de entrada; valores medios de los parámetros de entrada dan una buena estimación de la duración media del proyecto; las aritméticas de intervalo e intervalos interior dan una sobreestimación y subestimación de los tiempos de duración de proyecto respectivamente.Galvez, ED.; Ordieres, JB.; Capuz-Rizo, SF. (2015). Evaluation of Project Duration Uncertainty using the Dependency Structure Matrix and Monte Carlo Simulations. Revista de la Construcción (Online). 14(2):72-79. doi:10.4067/S0718-915X2015000200010S727914