We present a novel optimisation approach for incentive contract design within a project setting. the structure of the remuneration is one of the key challenges faced by the project owner when (s)he decides to hire a contractor. The proposed technique builds on the recently proposed contract design methodology by Kerkhove and Vanhoucke (Omega, 2015). Specifically, a novel multi-objective scatter search heuristic is proposed and implemented using parallelisation. Both single- and multi-population implementations of this heuristic are compared to the original full-factorial approach as well as commercial optimisation software. The results of the computational experiments indicate that the single-population parallel scatter search procedure significantly outperforms the other solution strategies in terms of both speed and solution quality.
Vanacker, Tom; Heughebaert, Andy; Manigart, Sophie (2014)
This paper provides an analysis of the long- and short-run determinants of domestic bank lending to the private sector in eleven Central, Eastern and Southeastern European (CESEE) countries. We identify regime shifts for the observation period of 1997 to 2009, and the resulting subperiods are characterized by a different impact of the credit growth determinants. Estimating a credit demand equation as the long-term relation, we find – for most countries – a cointegration relationship with economic activity. We then examine the shortrun dynamics by applying both a linear and a nonlinear (Markov-switching) error correction model. While there is a significant correlation between credit growth and supply factors, namely bank deposits and banks’ equity, its impact differs across the subperiods. Identified regime switches in the short-run relation are driven primarily by differences in the credit supply factors rather than by the adjustment toward the credit equilibrium as the error correction coefficients show only slight cross-regime differences. In terms of regime switching, we distinguish between two groups of countries: those with one dominant regime, which is only briefly interrupted by a second one, and those with two equally pronounced regimes. In the latter group, a marked switch occurred just before or when the global crisis hit the CESEE region in the latter part of 2008. This regime shift is associated with a decreased correlation between deposit and credit growth.
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.
In this paper, an overview is presented of the existing metaheuristic solution procedures to solve the multi-mode resource-constrained-project scheduling problem, in which multiple execution modes are available for each of the activities of the project. A fair comparison is made between the different metaheuristic algorithms on the existing benchmark datasets and on a newly generated dataset. Computational results are provided and recommendations for future research are formulated.
Although researchers have extensively stressed the critical role of line managers in the effective implementation of HR practices, little is known about what exactly causes managers to enact these practices. In this paper, we draw from signaling theory, theory of planned behavior and social exchange theory to investigate both the antecedents and the outcomes of front-line management's enactment of performance management (PM) activities. Results from two Belgian samples of 731 front-line managers and 425 employees show that line management's beliefs regarding the usefulness of PM activities mediate the relationship between HR support and line management's implicit person theory, on the one hand, and PM enactment, on the other. This relationship is moderated by the manager' span of control. Furthermore, line management enactment shows to be positively related to employee engagement and job satisfaction.
In this paper, the extended Resource Renting Problem (RRP/extended) is presented. The RRP/extended is a time-constrained project scheduling problem, in which the total project cost is minimised. In the RRP/extended, this total project cost is determined by a number of extra costs, which are defined in this paper. These costs are based on the costs that are used in the traditional Resource Renting Problem and the Total Adjustment Cost Problem. Therefore, the RRP/extended represents a union of these two problems. To solve the RRP/extended, a scatter search is developed. The building blocks of this scatter search are specifically designed for the RRP/extended. We introduce two crossovers and an improvement method. The efficiency of these building blocks will be shown in the paper. Furthermore, a sensitivity analysis is presented in which the five costs have diverse values.
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