The Project Scheduling Problem with Non-Deterministic Activities Duration: A Literature Review

Purpose: The goal of this article is to provide an extensive literature review of the models and solution procedures proposed by many researchers interested on the Project Scheduling Problem with nondeterministic activities duration. Design/methodology/approach: This paper presents an exhaustive literature review, identifying the existing models where the activities duration were taken as uncertain or random parameters. In order to get published articles since 1996, was employed the Scopus database. The articles were selected on the basis of reviews of abstracts, methodologies, and conclusions. The results were classified according to following characteristics: year of publication, mathematical representation of the activities duration, solution techniques applied, and type of problem solved. Findings: Genetic Algorithms (GA) was pointed out as the main solution technique employed by researchers, and the Resource-Constrained Project Scheduling Problem (RCPSP) as the most studied type of problem. On the other hand, the application of new solution techniques, and the possibility of incorporating traditional methods into new PSP variants was presented as research trends. Originality/value: This literature review contents not only a descriptive analysis of the published articles but also a statistical information section in order to examine the state of the research activity carried out in relation to the Project Scheduling Problem with non-deterministic activities duration.Peer Reviewe

A comparison of different redundancy based methods to solve the project scheduling problem with probabilistic activivies duration

Redundancy based methods are proactive scheduling methods for solving the Project Scheduling Problem (PSP) with non-deterministic activities duration. The fundamental strategy of these methods is to estimate the activities duration by adding extra time to the original duration. The extra time allows to consider the risks that may affect the activities durations and to reduce the number of adjustments to the baseline generated for the project. In this article, four methods based on redundancies were proposed and compared from two robustness indicators. These indicators were calculated after running a simulation process. On the other hand, linear programming was applied as the solution technique to generate the baselines of 480 projects analyzed. Finally, the results obtained allowed to identify the most adequate method to solve the PSP with probabilistic activity duration and generate robust baselines

Amortiguadores de tiempo en una planta de producción tipo a: metodología para su obtención y análisis

El desempeño de una planta de producción tipo A se encuentra condicionado por los RecursosRestrictivos de Capacidad, éstos son los recursos que determinan el ritmo de producción, por lotanto se convierten en un punto crítico al momento de resolver problemas relacionados con elexceso de inventario, la programación de la producción y el aumento en el costo del productoterminado. Por esta razón se planteó una metodología, la cual permite controlar y proteger larestricción del sistema de producción de situaciones como por ejemplo, las variaciones deltiempo de procesamiento en las estaciones de trabajo, la dependencia entre ellas y el efectoMurphy que se presenta durante la producción. Con esta metodología se conoce el tamañofactible del Amortiguador de Tiempo, garantizando un flujo continuo de material, disminuciónel nivel de Inventario y mejorando la eficiencia en el sistema productivo.The peiformance 01the production 01type A plant is conditioned by the restrictive resources ofcapacity. These resources determine the production rhythm, making them the critical factor insolvingproblems re/ated to the units' excess, schedule ofproduction and the increase in thefinalpraduct cas!. This is why a procedure was established to protect and control the restrictions inthe production system in situations like, time variations in the production process at workstafions, Ihe dependence among them and Ihe murphy effeet that is presented during theproduefion. Thanks lo this procedure, it is possible to know the size of the time buffer whichguaranties thepermanent materialjlow, decrease in production stocks and improve the efficiencyofthe producfion system