• 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 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 (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)
    • A decision support system for surgery sequencing at UZ Leuven's day-care department

      Cardoen, Brecht; Demeulemeester, Erik (International Journal of Information Technology & Decision Making, 2011)
    • A dual-population genetic algorithm for the single machine maximum lateness problem

      Sels, Veronique; Vanhoucke, Mario (Lecture notes in Computer Science, 2011)
    • A finite capacity production scheduling procedure for a belgian steel company

      Vanhoucke, Mario; Debels, Dieter (International Journal of Production Research, 2009)
    • A Framework for the Study of Positive Deviance in Organizations

      Mertens, Willem; Recker, Jan; Kohlborn, T.; Kummer, T.F. (Deviant Behavior, 2016)
      Positive deviance describes behavior that deviates from salient norms, yet is positive in its intention or effect. It has received considerable attention in the sociology literature, and is increasingly being studied in the context of the workplace. The development of a cumulative tradition in this domain, however, is hindered by the continued coexistence of multiple definitions of positive deviance in organizations and the use of various measurements and research designs. In this article, we synthesize existing definitions and approaches to the organizational study of positive deviance, integrate them into a coherent conceptual framework, and offer methodological advice and illustrations.
    • A genetic algorithm for the preemptive and non-preemptive multi-mode resource-constrained project scheduling problem

      Van Peteghem, Vincent; Vanhoucke, Mario (European Journal of Operational Research, 2010)
    • A global investigation of key turning points in business process maturity

      McCormack, K.; Willems, Jurgen; Van den Bergh, Joachim; Deschoolmeester, Dirk; Willaert, Peter; Stemberger, Mojca; Skrinjar, Rok; Trkman, Peter; Ladeira, Marcelo Bronzo; Valadares de Oliveira, Marcos Paulo; Vuksic, Vesna; Vlahovic, Nikola (Business Process Management Journal, 2009)
    • A heuristic procedure to solve the project staffing problem with discrete time/resource trade-offs and personnel scheduling constraints

      Van Den Eeckhout, Mick; Maenhout, Broos; Vanhoucke, Mario (Computers & Operations Research, 2019)
      Highlights • Project staffing with discrete time/resource trade-offs and calendar constraints. • An iterated local search procedure is proposed. • Different problem decomposition techniques are applied. Abstract When scheduling projects under resource constraints, assumptions are typically made with respect to the resource availability and activities are planned each with its own duration and resource requirements. In resource scheduling, important assumptions are made with respect to the staffing requirements. Both problems are typically solved in a sequential manner leading to a suboptimal outcome. We integrate these two interrelated scheduling problems to determine the optimal personnel budget that minimises the overall cost. Integrating these problems increases the scheduling flexibility, which improves the overall performance. In addition, we consider some resource demand flexibility in this research as an activity can be performed in multiple modes. In this paper, we present an iterated local search procedure for the integrated multi-mode project scheduling and personnel staffing problem. Detailed computational experiments are presented to evaluate different decomposition heuristics and comparison is made with alternative optimisation techniques.