• A Bi-Population Based Genetic Algorithm for the Resource-Constrained Project Scheduling Problem

      Debels, Dieter; Vanhoucke, Mario (2005)
      The resource-constrained project scheduling problem (RCPSP) is one of the most challenging problems in project scheduling. During the last couple of years many heuristic procedures have been developed for this problem, but still these procedures often fail in finding near-optimal solutions for more challenging problem instances. In this paper, we present a new genetic algorithm (GA) that, in contrast of a conventional GA, makes use of two separate populations. This bi-population genetic algorithm (BPGA) operates on both a population of left-justified schedules and a population of right-justified schedules in order to fully exploit the features of the iterative forward/backward local search scheduling technique. Comparative computational results reveal that this procedure can be considered as today's best performing RCPSP heuristic.
    • A Bi-Population Based Genetic Algorithm for the Resource-Constrained Project Scheduling Problem

      Debels, Dieter; Vanhoucke, Mario (Lecture notes in Computer Science, 2005)
    • A buffer control method for top-down project control

      Martens, Annelies; Vanhoucke, Mario (European Journal of Operational Research, 2017)
      Timely completion of projects is an important factor for project success. However, projects often exceed their predefined deadline, which results in a late project delivery and an increase in the total project cost. In order to increase the probability of timely completion, a project buffer can be planned at the end of a project. During project execution, an assessment of the total buffer consumption at the project completion date can be made in order to periodically monitor the project progress. When the expected buffer consumption is higher than 100%, the project deadline is expected to be exceeded and the project manager should take corrective actions to get the project back on track. In this paper, a new buffer monitoring approach is introduced, which sets tolerance limits for Earned Value Management/Earned Schedule (EVM/ES) schedule performance metrics by allocating the project buffer over the different project phases. The purpose of these tolerance limits is to provide the project manager with accurate and reliable information on the expected project outcome during the project execution. A computational study is carried out to assess the performance of the proposed approach and to compare its performance with traditional buffer consumption monitoring procedures. Additionally, existing performance metrics for tolerance limits have been put into a hypothesis testing framework, and new metrics have been developed in order to fill the detected gaps in performance measurement. Results have shown that the proposed tolerance limits improve the performance of the monitoring phase, especially for parallel projects. Consequently, the underperformance of EVM/ES for parallel projects is mitigated by these limits.
    • A classification of development programmes and its consequences for programme management

      Vereecke, Ann; Pandelaere, Els; Deschoolmeester, Dirk; Stevens, Marleen (International Journal of Operations and Production Management, 2003)
    • A classification of programmes and its managerial impact

      Vereecke, Ann; Stevens, Marleen; Pandelaere, Els; Deschoolmeester, Dirk (2003)
      The paper describes the results of an exploratory research study on the application of programme management in six companies. A classification of programmes is developed that may help in understanding the differences between programmes and the managerial impact of these differences. The research shows that the formalised and rigorous approach as described in most programme management handbooks is not widely adopted. The cases show less centralisation, less formalisation and less management of the interdependencies between the projects in the programme than one would expect on the basis of the programme management literature. This is especially the case in programmes that originate as a grouping of a set of existing projects. Yet, formalisation is mentioned as the main success factor in managing programmes. Keywords: Programme management, project management, management of change
    • A classification scheme for operating room planning and scheduling problems

      Cardoen, Brecht; Demeulemeester, Erik; Beliën, Jeroen (2009)
    • A closer view at the patient surgery planning and scheduling problem: A literature review

      Samudra, Michael; Demeulemeester, Erik; Cardoen, Brecht (Review of Business and Economic Literature, 2013)
    • A comparative study of Artificial Intelligence methods for project duration forecasting

      Wauters, Mathieu; Vanhoucke, Mario (Expert Systems with Applications, 2016)
      This paper presents five Artificial Intelligence (AI) methods to predict the final duration of a project. A methodology that involves Monte Carlo simulation, Principal Component Analysis and cross-validation is proposed and can be applied by academics and practitioners. The performance of the AI methods is assessed by means of a large and topologically diverse dataset and is benchmarked against the best performing Earned Value Management/Earned Schedule (EVM/ES) methods. The results show that the AI methods outperform the EVM/ES methods if the training and test sets are at least similar to one another. Additionally, the AI methods report excellent early and mid-stage forecasting results. A robustness experiment gradually increases the discrepancy between the training and test sets and demonstrates the limitations of the newly proposed AI methods.
    • A comparison and hybridization of crossover operators for the nurse scheduling problem

      Maenhout, Broos; Vanhoucke, Mario (Annals of Operations Research, 2007)
    • A comparison of different project duration forecasting methods using earned value metrics

      Vandevoorde, Stephan; Vanhoucke, Mario (2005)
      Earned value project management is a well-known management system that integrates cost, schedule and technical performance. It allows the calculation of cost and schedule variances and performance indices and forecasts of project cost and schedule duration. The earned value method provides early indications of project performance to highlight the need for eventual corrective action. Earned value management was originally developed for cost management and has not widely been used for forecasting project duration. However, recent research trends show an increase of interest to use performance indicators for predicting total project duration. In this paper, we give an overview of the state-of-the-art knowledge for this new research trend to bring clarity in the often confusing terminology. The purpose of this paper is three-fold. First, we compare the classic earned value performance indicators SV & SPI with the newly developed earned schedule performance indicators SV(t) & SPI(t). Next, we present a generic schedule forecasting formula applicable in different project situations and compare the three methods from literature to forecast total project duration. Finally, we illustrate the use of each method on a simple one activity example project and on real-life project data. Keywords: Earned value, earned duration, earned schedule, project duration forecasting
    • A comparison of different project duration forecasting methods using earned value metrics

      Vandevoorde, Stephan; Vanhoucke, Mario (International Journal of Project Management, 2006)
    • A comparison of priority rules for the job shop scheduling problem under different flow time- and tardiness-related objective functions

      Sels, Veronique; Gheysen, Nele; Vanhoucke, Mario (International Journal of Production Research, 2012)
    • A comparison of the performance of various project control methods using earned value management systems

      Colin, Jeroen; Vanhoucke, Mario (Expert Systems with Applications, 2015)
      Recent literature on project management has emphasised the effort which is spent by the management team during the project control process. Based on this effort, a functional distinction can be made between a top down and a bottom up project control approach. A top down control approach refers to the use of a project control system that generates project based performance metrics to give a general overview of the project performance. Actions are triggered based on these general performance metrics, which need further investigation to detect problems at the activity level. A bottom up project control system refers to a system in which detailed activity information needs to be available constantly during the project control process, which requires more effort. In this research, we propose two new project control approaches, which combines elements of both top down and bottom up control. To this end, we integrate the earned value management/earned schedule (EVM/ES) method with multiple control points inspired by critical chain/buffer management (CC/BM). We show how the EVM/ES control approach is complementary with the concept of buffers and how they can improve the project control process when cleverly combined. These combined top down approaches overcome some of the drawbacks of traditional EVM/ES mentioned in the literature, while minimally increasing the effort spent by the project manager. A large computational experiment is set up to test the approach against other control procedures within a broad range of simulated dynamic project progress situations.
    • A concept discovery approach for fighting human trafficking and forced prostitution.

      Poelmans, Jonas; Elzinga, Paul; Viaene, Stijn; Dedene, Guido (+); Kuznetsov, Sergei O. (Lecture notes in Computer Science, 2011)
    • A decision support system for cyclic master surgery scheduling with multiple objectives

      Beliën, Jeroen; Demeulemeester, Erik; Cardoen, Brecht (Journal of Scheduling, 2009)