The research activities of our research group are situated in the design and development of algorithms for various kinds of scheduling problems. The OR&S group has been created in 2001 by Mario Vanhoucke. Since then, the group has grown in size and now contains several motivated researchers who all focus on combinatorial scheduling problems. Their work has resulted in two PhD’s (Dieter Debels and Broos Maenhout), 5 PhD projects in progress (Vincent Van Peteghem, Veronique Sels, Jeroen Coling, Thomas De Jonghe and Christophe Van Huele) and several publications in international journals (see publications).

The research activities can be subdivided into the following categories:

Project Scheduling

Data generation: The generation of project network data under a controlled design is an important research area for testing various project scheduling algorithms. Two network generation procedures have been developed, one in collaboration with the Technical University of Lisbon. More information can be found at our RanGen wegpage.

Time minimization: The resource-constrained project scheduling problem (RCPSP) is the basic problem type in project scheduling and aims at the minimization of the total project makespan. The project scheduling problem has been investigated under a single mode assumption (see the RCPSP webpage) or a multi-mode assumption (see the RCPDC-MM webpage).

Net present value maximization: The resource-constrained project scheduling problem with discounted cash flows (RCPSP-DC) aims at the the maximization of the net present value under various assumptions. This research topic has led to different research papers applied on different real-life projects. More information can be found at our RCPSP-DC webpage.

Time/cost optimization: The discrete time/cost trade-off problem (DTCTP) is an extension of the classical CPM method that assumes a linear trade-off between an activity’s duration and time. Exact and heuristic algorithms have been developed under various project assumptions. More information can be obtained at our DTCTP webpage.

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Personnel Scheduling

The nurse scheduling problem is a well-known scheduling problem which assigns nurses to shifts per day taking both hard and soft constraints into account. The objective is to maximize the preferences of the nurses and to minimize the total penalty cost from violations of the soft constraints. In this research track, we present various novel meta-heuristic techniques based on the principles of Genetic Algorithmic search, Scatter Search principles, Electromagnetism, etc... Moreover, we present an instance generator and a benchmark library of datafiles to facilitate future research. This generator and library can be downloaded from the Personnel Scheduling webpage.

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Earned Value Management

Since 2003, the OR&S group performs research to measure the forecast accuracy of earned value metrics in project management. It is well-known that well managed and controlled projects are more likely to be delivered on time and within budget. The construction of a (resource-feasible) baseline schedule and the follow-up during execution are primary contributors to the success or failure of a project. Earned value management systems have been set up to deal with the complex task of controlling and adjusting the baseline project during execution. Although earned value systems have been proven to provide reliable estimates for the follow-up of cost performance, it often fails to predict to total duration of the project.
The research is supported by the Project Management Institute (Belgian Chapter - www.pmi-belgium.be) and the International Project Management Association (www.ipma.ch). This research project is in close collaboration with Stephan Vandevoorde from Fabricom Airport Systems (www.fabricomairports.com). For information about this research topic, see our EVMS webpage.

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Production Scheduling

The single machine scheduling problem is one of the most basic machine scheduling problems that can be solved under various settings (job and activity characteristics, objective functions, etc...). Currently, a research project is in progress aiming at the development of various procedures for machine and patient scheduling problems. A practical procedure has been developed for a steel production company (www.sidmar.be) and decribed in an academic oriented paper. More information can be found at our Machine Scheduling website.

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Management Accounting

Together with the London School of Economics and the accountancy department of the faculty of Economics and Business Administration of Ghent university, simulation studies have been set up to investigate the role of the design of a costing system and the possible errors on the decision-making process.
Important research questions of this project are:

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