• Offshore grids for renewables: do we need particular regulatory framework

      Meeus, Leonardo (2015)
      Onshore, generators are connected to the transmission grid by TSOs. This regulatory model could simply be extended to offshore (i.e. Germany), but the connection of offshore wind farms to shore is also an opportunity to test alternatives, i.e. the third party model (i.e. the UK) or the generator model (i.e. Sweden). In this paper, we argue that the third party and generator models are indeed better suited to support the evolution towards larger scale offshore wind farms that are increasingly developed farther out to sea, while the TSO model is better suited to support the evolution towards cross-border offshore grid projects. In other words, an important trade-off needs to be made because none of the existing regulatory models can fulfill all the expectations in the current context in Europe. And, the trade-off has to be made at the regional or EU level because the different national regulatory frameworks are incompatible when applied to a cross-border offshore grid project.
    • On becoming a beyonder

      Van den Broeck, Herman; Venter, David (2012)
      This study analyzes the effect of different external technology sourcing modes on the creation of radical innovation in companies. Moreover, since prior research has indicated that exploration consists of looking beyond both organizational and technological boundaries, the role of technological distance between the partnering firms and the role of technological newness are also included. In particular, this paper examines how they affect the relationship between external technology sourcing and the creation of pioneering technologies (technologies that do not build on any existing technologies), which are used as a proxy for radical innovations. Using a sample of companies that were from the pharmaceutical industry, the results indicate that strategic alliances and corporate venture capital investments have a positive effect on the creation of pioneering technologies, whereas the effect of M&As is found to be negative. Additionally, the results show that the impact of these governance modes on the creation of pioneering technology is indeed affected by the newness of the technology and relatedness of the technological portfolios of the partnering firms. A larger technological distance between the two partnering firms increases the effect of strategic alliances on the creation of pioneering technologies. In addition, the results indicate that technological newness weakens the positive effect of CVC investments and non-equity alliances on the creation of pioneering technologies.
    • On maximizing the net present value of a project under renewable resource constraints

      Vanhoucke, Mario; Demeulemeester, Erik; Herroelen, Willy (2001)
      The resource-constrained project-scheduling problem with discounted cash flows is studied. Each activity of this resource-constrained project-scheduling problem has certain resource requirements and a known deterministic cash flow that can be either positive or negative. Deterministic cash flows are assumed to occur over the duration of the activities. Progress payments and cash outflows occur at the completion of activities. The objective is to schedule the activities subject to a fixed deadline to maximize the net present value subject to the precedence and resource constraints. With these features the financial aspects of project management are taken into account. A depth-first branch-and-bound algorithm that makes use of extra precedence relations is introduced to resolve a number of resource conflicts and a fast recursive search algorithm for the max-npv problem to compute upper bounds. The recursive search algorithm exploits the idea that positive cash flows should be scheduled as early as possible while negative cash flows should be scheduled as late as possible within the precedence constraints. The procedure has been coded in Visual C++, Version 4.0 under Windows NT, and has been validated on two problem sets.
    • On sample marginal quantiles for stationary processes

      Dominicy, Yves; Hörmann, Siegfried; Ogata, Hiroaki; Veredas, David (2013)
    • On the Design of Custom Packs: Grouping of Medical Disposable Items for Surgeries

      Cardoen, Brecht; Beliën, Jeroen; Vanhoucke, Mario (2015)
      A custom pack combines medical disposable items into a single sterile package that is used for surgical procedures. Although custom packs are gaining importance in hospitals due to their potential benefits in reducing surgery setup times, little is known on methodologies to configure them, especially if the number of medical items, procedure types and surgeons is large. In this paper, we propose a mathematical programming approach to guide hospitals in developing or reconfiguring their custom packs. In particular, we are interested in minimising points of touch, which we define as a measure for physical contact between staff and medical materials. Starting from an integer non-linear programming model, we develop both an exact linear programming (LP) solution approach and an LP-based heuristic. Next, we also describe a simulated annealing approach to benchmark the mathematical programming methods. A computational experiment, based on real data of a medium-sized Belgian hospital, compares the optimised results with the performance of the hospital's current configuration settings and indicates how to improve future usage. Next to this base case, we introduce scenarios in which we examine to what extent the results are sensitive for waste, i.e. adding more items to the custom pack than is technically required for some of the custom pack's procedures, since this can increase its applicability towards other procedures. We point at some interesting insights that can be taken up by the hospital management to guide the configuration and accompanying negotiation processes.
    • On the differential effects of European patents

      Vanhaverbeke, Wim; Van Cayseele, Patrick (1993)
    • On the performance of priority rules for the stochastic resource constrained multi-project scheduling problem

      Wang, Yanting; He, Zhengwen; Kerkhove, Louis-Philippe; Vanhoucke, Mario (Elsevier, 2017)
      The majority of research studies the resource constrained multi-project scheduling problem in a deterministic environment, regardless of the uncertainty nature of the environment. In this paper, we assume that the activity duration is a stochastic variable, and propose two new robustness measures to analyse the performance of priority rules under a stochastic environment. A full factorial experiment is designed to solve the problem and investigate the relationship between project characteristics and the performance of priority rules. Furthermore, a trade-off relationship between the quality and robustness is investigated and the best priority rules are recommended from both a project and portfolio managers perspective.
    • On the performance of priority rules for the stochastic resource constrained multi-project scheduling problem

      Wang, Yanting; He, Zhengwen; Kerkhove, Louis-Phillipe; Vanhoucke, Mario (Elsevier, 2017)
      The majority of research studies the resource constrained multi-project scheduling problem in a deterministic environment, regardless of the uncertainty nature of the environment. In this paper, we assume that the activity duration is a stochastic variable, and propose two new robustness measures to analyse the performance of priority rules under a stochastic environment. A full factorial experiment is designed to solve the problem and investigate the relationship between project characteristics and the performance of priority rules. Furthermore, a trade-off relationship between the quality and robustness is investigated and the best priority rules are recommended from both a project and portfolio managers perspective.
    • On the resource renting problem with overtime

      Kerkhove, Louis-Philippe; Vanhoucke, Mario; Maenhout, Broos (Elsevier Business Information, 2017)
      In this paper the Resource Renting Problem with Overtime (RRP/overtime) is presented. The RRP/overtime is a new problem in which the assumptions of the basic RRP are combined with the possibility to schedule (parts of) activities during overtime. The addition of this extension increases the applicability of the RRP to real world problems. This paper also presents a solution technique for this extension of the resource renting problem. The solution procedure uses a scatter search heuristic to optimize a priority list, which is then in turn used by a schedule generation scheme (PatSGS). A variation on this schedule generation scheme is also used in dedicated local search procedures. The third contribution of this research is a new lower bound for the RRP/overtime problem, which is used to evaluate the results of the proposed heuristic solution method.
    • On the use of multivariate regression methods for longest path calculations from earned value management observations

      Vanhoucke, Mario; Colin, Jeroen (2016)
      This paper explores the use of multivariate regression methods for project schedule control within a statistical project control framework. These multivariate regression methods monitor the activity level performance of an ongoing project from the earned value management/earned schedule (EVM/ES) observations that are made at a high level of the work breakdown structure (WBS). These estimates can be used to calculate the longest path in the project and to produce warning signals for project schedule control. The effort that is spent by the project manager is thereby reduced, since a drill-down of the WBS is no longer required for every review period. An extensive computational experiment was set up to test and compare four distinct multivariate regression methods on a database of project networks. The kernel principal component regression method, when used with a radial base function kernel, was found to outperform the other presented regression methods.
    • On the use of planning models in the operating theatre: Results of a survey in Flanders

      Cardoen, Brecht; Demeulemeester, Erik; Van der Hoeven, J. (2010)
    • On the use of Schedule Risk Analysis for Project Management

      Vanhoucke, Mario (2015)
      The purpose of this paper is to give an overview on the existing literature and recent developments on the research on Schedule Risk Analysis (SRA) in Project Management (PM) to measure the sensitivity of activities and resources in the project network. SRA is a technique that relies on Monte-Carlo simulation runs to analyze the impact of changes in activity durations and costs on the overall project time and cost objectives. First, the paper gives an overview of the most commonly known sensitivity metrics from literature that are widely used by PM software tools to measure the time and cost sensitivity of activities as well as sensitivity for project resources. Second, the relevance of these metrics in an integrated project control setting is discussed based on some recent research studies. Finally, a short discussion on the challenges for future research is given. All sections in this paper are based on research studies done in the past for which references will be given throughout the manuscript.
    • On tomorrow's grounds', Flemish agriculture in 2030: a case of participatory translation of sustainability principles into a vision for the future

      Nevens, Frank; Dessein, J.; Meul, M.; Rogge, E.; Verbruggen, I.; Mulier, A.; Van Passel, Steven; Lepoutre, Jan; Hongenaert, M. (2008)
    • Onboarding alleen is niet voldoende

      Vandenbroucke, Astrid (Editions NMG SPRL, 2017)
      Organisaties menen al snel dat ze goed scoren wanneer het gaat over het onboardingproces van nieuwe leidinggevenden. In realiteit loop het echter niet altijd van een leien dak. Vooral grotere bedrijven doen het relatief goed op vlak van administratieve basisproducedes, maar onboarding doet weinig tot niets wanneer die werknemers met onbekende culturele normen en verwachtingen te maken krijgen. De inspanningen die organisaties leveren voor integratie verschillen sterk en dit laat tijd, prestatie en talent management niet ongeschonden.
    • Onderzoek naar carrièresystemen voor R&D-professionals

      Buyens, Dirk; Debackere, Koenraad; Vandenbossche, Tine (1995)