Recent Submissions

  • Analysis of lead time correlation under a base-stock policy (Accepted)

    Hellemans, Tim; Boute, Robert; Van Houdt, Benny (Elsevier, 2019)
    We analyze the impact of lead time correlation on the inventory distribution, assuming a periodic review base-stock policy. We present an efficient method to compute the shortfall distribution for any Markovian lead time process, and we provide structural results when lead times are characterized by a 2-state Markov-modulated process. The latter reveals how lead time correlation increases the inventory variance and enables a closed form for the asymptotic behavior of the shortfall's variance in case the two possible lead time values are sufficiently different. We also establish upper and lower bounds on the inventory variance, which hold for any general time-homogeneous lead time process. Our results are complemented by a numerical experiment that indicates how commonly used approximations of the shortfall distribution mis-specify base-stock levels in the presence of lead time correlation. Not only does the inventory distribution increase in variance as the lead time correlation increases, it also becomes multi-modal.
  • The impact of solution representations on heuristic net present value optimization in discrete time/cost trade-off project scheduling with multiple cash flow and payment models

    Leyman, Pieter; Van Driessche, Niels; Vanhoucke, Mario; De Causmaecker, Patrick (Elsevier, 2019)
    The goal of this paper is to investigate the impact of different solution representations, as part of a metaheuristic approach, on net present value optimization in project scheduling. We specifically consider the discrete time/cost trade-off problem with net present value optimization and apply three payment models from literature. Each of these models determines the timing and size of cash flows from the contractor’s viewpoint. The contribution of this paper to literature is twofold. First, we include cash flow distribution variants in the payment models, to also distinguish between different manners in which value is created and costs are incurred, as part of a general model for the contractor’s cash flow management. This general model is developed in order to explicitly include the progress of activities in the determination of the timing and size of payments to the contractor, which is currently lacking in literature. Second, we employ an iterated local search framework to compare different solution representations and their corresponding local search and repair heuristics. The goal is to unambiguously show that the choice of a solution representation deserves a fair amount of attention, alongside the selection of appropriate diversification and intensification operators, even though this is not always the case in literature. Each part of the proposed algorithm is validated on a large dataset of test instances, generated to allow for a broad comparison of the solution representations. Our results clearly quantify the statistically significant differences between three types of representations for the project scheduling problem under study.
  • Computing project makespan distributions: Markovian PERT networks revisited

    Burgelman, Jeroen; Vanhoucke, Mario (Elsevier, 2019)
    This paper analyses the project completion time distribution in a Markovian PERT network. Several techniques to obtain exact or numerical expressions for the project completion time distribution are evaluated, with the underlying assumption that the activity durations are exponentially distributed random variables. We show that some of the methods advocated in the project scheduling literature are unable to solve standard datasets from the literature. We propose a framework to analyse the applicability, accuracy and sensitivity of different methods to compute project makespan distributions. An alternative data generation process is proposed to benchmark the different methods and the influence of project dataset parameters on the obtained results is extensively assessed.
  • Tolerance limits for project control: An overview of different approaches (Published Online)

    Vanhoucke, Mario (Elsevier, 2018)
    Monitoring the performance of projects in progress and controlling their expected outcome by taking corrective actions is a crucial task for any project manager. Project control systems are in use to quantify the project performance at a certain moment in time, and allow the project manager to predict the expected outcome if no action is taken. Consequently, these systems serve as mechanism that provide warning signals that tell the project manager when it is time to take corrective actions to bring the expected project outcome back on track. In order to trust these generated warning signals, the project manager has to set limits on the provide performance metrics that serve as thresholds for these actions. This paper gives an overview of different approaches discussed in the literature to control projects using such actions thresholds. First and foremost, the paper discusses three classes of actions thresholds,ranging from very easy-to-use rules-of-thumb to more advanced statistical project control methodologies. Each of these tools have been the subject to research studies, each of which aim at showing their power to predict project problems during its progress. In addition, the paper will emphasize the fundamental different between statistical project control using tolerance limits and statistical process control for projects. Finally, three different quality metrics to evaluate the performance of such control methods are presented and discussed.
  • The regulatory experience of Italy and the United States with dedicated incentives for strategic electricity transmission investment

    Keyaerts, Nico; Meeus, Leonardo (Elsevier, 2017)
    There is a trend in regulatory practice towards providing dedicated incentives for strategic investments. Italy and the United States have the longest experience with authorizing returns and risk-mitigating incentives that deviate from standard regulatory treatment for policy purposes. In these countries, the regulatory incentives are based on a case-by-case assessment of capital projects. We find that the Italian scheme is simpler, which reduces administrative costs. The U.S. scheme is more advanced in the case-by-case assessment. Even though dedicated incentives may be controversial, our analysis of both experiences shows that, notwithstanding significant learning costs, both schemes have facilitated substantial financial investment in strategically important infrastructure.
  • A tabu search procedure for the resource-constrained project scheduling problem with alternative subgraphs

    Servranckx, T.; Vanhoucke, Mario (Elsevier, 2019)
    This paper investigates the resource-constrained project scheduling problem with alternative subgraphs (RCPSP-AS). In this scheduling problem, there exist alternative ways to execute subsets of activities that belong to work packages. One alternative execution mode must be selected for each work package and, subsequently, the selected activities in the project structure should be scheduled. Therefore, the RCPSP-AS consists of two subproblems: a selection and a scheduling subproblem. A key feature of this research is the categorisation of different types of alternative subgraphs in a comprehensive classification matrix based on the dependencies that exist between the alternatives in the project structure. As the existing problem-specific datasets do not support this framework, we propose a new dataset of problem instances using a well-known project network generator. Furthermore, we develop a tabu search that uses information from the proposed classification matrix to guide the search process towards high-quality solutions. We verify the overall performance of the metaheuristic and different improvement strategies using the developed dataset. Moreover, we show the impact of different problem parameters on the solution quality and we analyse the impact of distinct resource characteristics of alternatives on the selection process.
  • Judgmental forecast adjustments over different time horizons (Published Online)

    Van den Broeke, Maud; De Baets, Shari; Vereecke, Ann; Baecke, Philippe; Vanderheyden, Karlien (Elsevier, 2018)
    Accurate demand forecasting is the cornerstone of a firm’s operations. The statistical system forecasts are often judgmentally adjusted by forecasters who believe their knowledge can improve the final forecasts. While empirical research on judgmental forecast adjustments has been increasing, an important aspect is under-studied: the impact of these adjustments over different time horizons. Collecting data from 8 business cases, retrieving over 307,200 forecast adjustments, this work assesses how the characteristics (e.g., size and direction) and accuracy of consecutive adjustments change over different time horizons. We find that closer to the sales point, the number of adjustments increases and adjustments become larger and more positive; and that adjustments, both close and distant from the sales point, can deteriorate the final forecast accuracy. We discuss how these insights impact operational activities, such as production planning.
  • Short selling in extreme events

    Geraci, Marco Valerio; Garbaravicius, Tomas; Veredas, David (Elsevier, 2018)
    We study the association between daily changes in short selling activity and financial stock prices during extreme events using TailCoR, a measure of tail correlation. For the largest European and US banks, as well as European insurers, we uncover a strong relation during exceptional (extreme) days and a weak relation during normal (average) days. Examining days with large increases in short positions and large downfalls in stock prices, we find evidence of both momentum and contrarian short selling taking place. For North American bank stocks, contrarian short selling appears more practiced than for European bank and insurance stocks. We find that the uncovered relationship decreases with firm size and increases during ban periods, which is in line with short selling becoming more informative when constrained.
  • Governance implications of attracting external equity investors in private family firms

    Neckebrouck, Jeroen; Meuleman, Miguel; Manigart, Sophie (Academy of Management, 2018)
  • 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 (Pergamon Press, 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.
  • The view of angels from above: Angel governance across institutional environments (Published Online)

    Collewaert, Veroniek; Filatotchev, Igor; Khoury, Ted (Academy of Management, 2018)
    Compared to scholarship focused on venture capital, we know less about angel investing and, in particular, less about how angels operate across institutional environments. Given the importance of angels within early-stage entrepreneurial investment growing globally, the field of angel governance is poised for further investigation. Thus, in this paper, we begin the conversation on angels and institutions and provide a framework for studying the post-investment governance role taken by angels amid institutional variation. First, we provide a review of the research conducted on angel-centered corporate governance. We then explore how the regulative, normative, and cultural-cognitive institutional domains may influence angel governance arrangements. Within these domains, we isolate how the extent, frequency, and mode of angel engagement with the target venture can be shaped by the institutional environment.
  • A better way to share the gains of collaborative shipping

    Boute, Robert; Van Steendam, Tom (Peerless Media, 2018)
    Collaborative shipping typically leads to cost savings. However, it's not always easy to determine each partner's contribution to the gains and to share them accordingly. An industry-oriented method has been tested in a set of pilots and promises to be fair, transparent and not overly complex.
  • Digital probes as opening possibilities of generativity

    Jarvenpaa, Sirkka; Standaert, Willem (Association for Information Systems, 2018)
    The information systems research on generativity promises unprompted, innovative inputs from uncoordinated audiences, whose participation with heterogeneous technological resources generates diverse outputs and opens new possibilities. The question is how to perpetuate the openness on which the outputs of generativity rely. We advance, as a potential mechanism of generativity, the concept of digital probes, which leverage human and technological resources in hybrid digital and physical environments. The aesthetically rich probes challenge values, identities, and practices, cultivating emotional tensions that can reveal previously unexplored and unimagined possibilities, resulting in novel ideas, thoughts, and expressions. The new possibilities reveal what is hidden; reconfigure practices; cross-appropriate technological and social resources; and thereby further expand what can be experienced, viewed, and imagined. Further, the new possibilities draw new actors that again view things differently and seek different experiences, thus fueling emotional tensions that in turn open new possibilities, without settling them. We illustrate digital probes and their effects at Formula E. Formula E is a new motorsports venture that leveraged eSports, social media, crowdsourcing, and driverless cars in digital probes to reveal and examine previously unimagined possibilities of what the world of motorsport could be in the digital era. We end by exploring future research directions.
  • Relocation to get venture capital: a Resource dependence perspective (Published Online)

    De Prijcker, Sofie; Manigart, Sophie; Collewaert, Veroniek; Vanacker, Tom (Sage, 2017)
    Using a resource dependence perspective, we theorize and show that non-venture-capital-backed ventures founded in U.S. states with a lower availability of venture capital (VC) are more likely to relocate to California (CA) or Massachusetts (MA)—the two VC-richest states—compared to ventures founded in states with a greater availability of VC. Moreover, controlling for self-selection, ventures that relocate to CA or MA subsequently have a greater probability of attracting initial VC compared to ventures that stay in their home state. We discuss the implications for theory, future research, and practice.
  • Combining EDM and EVM a proposal simplification for project time and cost management

    De Andrade, Paulo André; Vanhoucke, Mario (Mundo Press, 2017)
    Earned value management (EVM), a technique mainly used to manage project cost, was developed during the second half of the twentieth century by an agency of the USA government. It was enriched, at the beginning of the current century, with an extension named earned schedule (ES) (Lipke, 2003), which added to EVM the capability to manage the project schedule. In 2014, earned duration management (EDM), a novel, and monetary value free technique for project schedule management, was proposed by Khamooshi and Golafshani (2014). Earned duration (ED), the project schedule indicator from EDM uses only activity dates and durations from EVM, and aims at replacing ES. By not using cost as a proxy for time, ED overcomes one of the most criticized aspect of ES. This paper intends to (i) compare ED with ES to learn some fundamental lessons, (ii) propose the combination of ED and planned value (PV) from EVM to produce an EDM-based project-level earned value (EVd), and (iii) assess the adequacy of EVd as an alternative to earned value (EV) from EVM in project time and cost management. The comparison between the project real cost and both EVM and EDM-based independent estimates at completion, on a set of real projects, was the vehicle for assessing the adequacy of EVd as a viable alternative to EV. Workload avoidance by replacing activities earned value calculations with the simpler and more consistent determination of the activities earned durations, and the enhanced visibility of potential schedule problems caused by lower cost/duration ratio activities, are benefits that EVd offers to project managers.
  • Shifting focus: Antecedents and outcomes of proactive feedback seeking from peers

    De Stobbeleir, Katleen; Ashford, Susan; Zhang, C. (Sage, 2018)
  • When social comparison is not always motivating for goal achievement (Accepted)

    Chan, Elaine; Briers, Barbara (Journal of Consumer Research Inc., 2018)
  • Een eenvoudig raamwerk voor IT-strategievorming in een lokaal bestuur

    Van den Bergh, Joachim; Viaene, Stijn (Vlaamse Vereniging voor Bestuur en Beleid vzw in samenwerking met uitgeverij die Keure, 2018)
    Vele lokale besturen in Vlaanderen kampen met een lage IT-maturiteit, gebrekkige of onbestaande IT-strategieën en beperkte affiniteit van de beleidsvoerders met digitale technologieën met een hoge ontwikkelingssnelheid. Plaats deze vaststelling in de context van schaarse middelen en een verregaande digitaliseringsnood en ambitie van de overheid en de uitdaging voor (in het bijzonder kleine en middelgrote) besturen wordt tastbaar. Een aantal lokale besturen dreigt vast te lopen in het reactief en ad hoc aanpakken van hoogdringende problemen. Het Provinciaal Intern Verzelfstandigd Agentschap (piva) eGOV ontwikkelde een nieuwe dienstverlening voor de steden en gemeenten in de provincie Oost-Vlaanderen om de achterstand om te buigen door middel van een eenvoudige aanpak om een lokale IT-strategie te formuleren. Concreet biedt de nieuwe dienstverlening een antwoord op de basisuitdaging voor elk lokaal bestuur om keuzes te maken voor IT, met digitale transformatie van de overheid als context. De aanleiding was het nieuwe aanbod van piva eGov (deels gefinancierd door VVSG) als opvolgingstraject voor die besturen die zwak tot matig scoorden in de I-monitorbevraging (Vlaamse IT audit). Piva eGov heeft dit aangegrepen om een nieuwe dienstverlening uit te bouwen, met een nieuwe manier van werken voor zichzelf en haar klanten. De doelstelling was om via een gefaciliteerd proces strategische en operationele keuzes voor IT in een lokaal bestuur te faciliteren, met IT en business op gelijke voet. Het proces werd uitgebouwd in een vorm van Action-Design Research (ADR) (SEIN et al. 2011), dit wil zeggen parallel met de uitvoering door piva eGov, en is met succes toegepast bij vier pilootbesturen. In dit artikel presenteren we de manier van werken, de resultaten en de voornaamste leerpunten voor overheden op het regionale, provinciale en lokale niveau, met het oog op het haalbaar maken van IT-strategievorming in lokale besturen.
  • Systemic risk in the US: Interconnectedness as a circuit breaker

    Dungey, Mardi; Luciani, Matteo; Veredas, David (Elsevier, 2018)
    We measure systemic risk via the interconnections between the risks facing both financial and real economy firms. SIFIs are ranked by building on the Google PageRank algorithm for finding closest connections. For a panel of over 500 US firms over 2003–2011 we find evidence that intervention programs (such as TARP) act as circuit breakers in crisis propagation. The curve formed by the plot of firm average systemic risk against its variability clearly separates financial firms into three groups: (i) the consistently systemically risky (ii) those displaying the potential to become risky and (iii) those of little concern for macro-prudential regulators.
  • Equity crowdfunding, shareholder structures, and firm performance

    Walthoff-Borm, Xavier; Vanacker, Tom; Collewaert, Veroniek (Wiley, 2018)
    Research question/issue: This paper provides a first‐time glimpse into the postcampaign financial and innovative performance of equity‐crowdfunded (ECF) and matched nonequity‐crowdfunded (NECF) firms. We further investigate how direct and nominee shareholder structures in ECF firms are associated with firm performance. Research findings/insights: We find that ECF firms have 8.5 times higher failure rates than matched NECF firms. However, 3.4 times more ECF firms have patent applications than matched NECF firms. Within the group of ECF firms, we find that ECF firms financed through a nominee structure make smaller losses, whereas ECF firms financed through a direct shareholder structure have more new patent applications, including foreign patent applications. Theoretical/academic implications: Our findings suggest that there are important adverse selection issues on equity crowdfunding platforms, although these platforms also serve as a catalyst for innovative activities. Moreover, our findings suggest that there is a more complex relationship between dispersed versus concentrated crowd shareholders and firm performance than currently assumed in the literature. Practitioner/policy implications: For policy makers and crowdfunding platforms, investor protection against adverse selection will be important to ensure the sustainability of equity crowdfunding markets. For entrepreneurs and crowd investors, our study highlights how equity crowdfunding and the adopted shareholder structure relate to short‐term firm performance.

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