Now showing items 21-40 of 6050

    • Toon: Eneco's smart platform for selling less energy to the home

      Steve, Muylle; Niraj, Dawar (2018)
      Eneco Group, the second largest utility company in the Netherlands, launched a smart thermostat, Toon, that served as a platform for energy management services. Toon quickly became the gold standard for smart homes in the Netherlands. In January 2017, top management needed to discuss the strategic priorities to keep Toon’s lead and hold off the competition.
    • 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.
    • Fine-slicing global value chains: A protection for proprietary content

      Gooris, Julien; Peeters, Carine (2014)
      This study shows that firms adjust the scope of activities entrusted to foreign services production units to adapt their knowledge and content protection strategy to the availability of strong legal protection or internal control mechanisms. We hypothesize and empirically confirm that, when the above mechanisms are not available, firms use the substitute protection mechanism of “fine-slicing” foreign value chain activities to exploit the complementarities that exist between tasks and reduce misappropriation hazard. We also find a positive moderating effect of firm country-specific experience and content value on the propensity to use the fine-slicing mechanism.
    • Implications of switching from a to-day to a to-week patient scheduling strategy, an application at the UZ Leuven

      Samudra, Michael; Demeulemeester, Erik; Cardoen, Brecht (2013)
      In most hospitals there are some patients who receive surgery later than required. As their health condition can potentially quickly worsen, they are exposed to a health risk. In order to improve the current situation, the lateness of patients has to be, firstly, quantified and, secondly, the responsible mechanism has to be understood, namely the patient scheduling process. We analyzed the percentage of patients being served late in Belgium’s largest hospital, the UZ Leuven. At the hospital, an elective patient is associated with one of five due time intervals within which the patient has to be served. We analyzed the lateness of patients across disciplines using all data from 2012 and 22 ORs. We tried to understand many of the different aspects related to the scheduling process, which knowledge we then included into a simulation model. We investigated from the data: patient arrival patterns, the relation between estimated and realized surgery durations, rescheduling mechanisms and the allocation patterns of emergencies. We also used the model to investigate the effects of switching from the current scheduling practice of assigning surgeries directly to slots (OR and day) to a two-step procedure, where patients are scheduled to a surgery week first and only in a second step to slots. Our results suggest that in case of the two-step procedure it is very important to allow patients with shorter due times to break into the already fixed weekly schedule. Additionally, it is important that in the second step of the scheduling procedure, in the within week scheduling, the due time is considered. We conclude that improving patient scheduling can help to decrease the amount of patients served too late. As a next step, we try to develop a sound scheduling schema, which allows to further decrease the number of patients served to late.
    • Dynamics of persistent heterogeneity in the global configuration of business services value chains

      Peeters, Carine; Lewin, Arie (2014)
      The paper develops an integrative framework that identifies, describes and links the firm-specific and non-firmspecific factors that co-evolve and mutually influence the changes in configurations of global business services value chains over time. We focus on the heterogeneity of configurations resulting from idiosyncratic choices regarding what processes to unbundle, what activities to locate where, and what control mechanisms to use. Expanding current models and empirical studies in International Business, we argue in particular in favour of a behavioural approach that gives more room to decision makers and the decision making process to explain changing but persistent heterogeneity in ALC configuration (Activity-Location-Control mechanisms) of business Page 44 TUESDAY AIB 2014 Conference Proceedings services global value chains.
    • The value of neighborhood information in prospect selection models investigating the optimal level of granularity

      Van den Poel, Dirk; Baecke, Philippe (2013)
      Within analytical customer relationship management (CRM), customer acquisition models suffer the most from a lack of data quality because the information of potential customers is mostly limited to socio-demographic and lifestyle variables obtained from external data vendors. Particularly in this situation, taking advantage of the spatial correlation between customers can improve the predictive performance of these models. This study compares the predictive performance of an autoregressive and hierarchical technique in an application that identifies potential new customers for 25 products and brands. In addition, this study shows that the predictive improvement can vary significantly depending on the granularity level on which the neighborhoods are composed. Therefore, a model is introduced that simultaneously incorporates multiple levels of granularity resulting in even more accurate predictions.
    • Telepresence in Business Meetings

      Standaert, Willem; Muylle, Steve; Basu, Amit (2014)
    • Delay in filing the financial statements: An empirical analysis among small firms

      Van Caneghem, Tom; Luypaert, Mathieu; Van Uytbergen, Steve (2014)
      We examine delay in filing the financial statements among a large sample of Belgian small firms and find that reporting delay is affected by demand for information (e.g., larger firms tend to report more quickly); specific reporting incentives (e.g., firms tend to delay the disclosure of unfavorable information); and the financial reporting “production process” (e.g., older firms tend to report quickly, which is consistent with a learning curve effect). We note that there is a subsample of early filers, for which the drivers of financial reporting timeliness are found to be different from those identified based on the full sample. Our results further indicate that extremely late filings are associated with lower financial statement quality. Importantly, about 31 percent of the financial statements in our sample are being filed late (i.e., after the legal deadline), but our results suggest that monetary sanctions could be an effective tool in order to ensure compliance with the imposed legal deadline.
    • Improving profitability of vehicle routing problems through advanced analytics

      Vercamer, Dauwe; Van den Poel, Dirk; Gendreau, Michel; Baecke, Philippe (2014)
      Based on a real case in door-to-door sales, the study assesses whether revenue predictions coming from transactional data can effectively be used to improve fleet schedules. To do this, two different customer selection models are compared. In the static model, customers are first chosen based on the revenue predictions and then routed through a VNS. The dynamic model uses the predictions in an orienteering problem. Initial results show that the dynamic approach is the most profitable.
    • How external and internal organizational image impact absenteeism

      De Stobbeleir, Katleen; Caniels, Marjolein; De Clippeleer, Inge; Deprez, Jana; Buyens, Dirk (2014)
      In this study, we investigate how an organization’s employer brand may impact important organizational outcomes. Specifically, using a sample of 59 Belgian companies, we assess the relative importance of employee evaluations and external evaluations in predicting one of the most important HRM concerns in organizations, i.e., absenteeism. Results show that absenteeism decreases both as a function of employees’ views and of outsiders’ views of the organization. Results further show that external perceptions of an employer may be a more important driver of absenteeism than the internal image. Such results highlight the importance of studying organizations’ external image in impacting important employee outcomes.
    • Towards the validity emotional intelligence: Testing the positive manifold with emotion recognition

      Boros, Smaranda; Eisenhaft, N.; Laukka, P.; Thingujam, N.; Elfenbein, H. (2015)
    • Quantile-based inference for tempered stable distributions

      Veredas, David; Fallahgoul, Hassan; Fabozzi, Frank (2015)
      A simple, fast, and accurate method for the estimation of numerous distributions that belong to the tempered stable class is introduced. The method is based on the Method of Simulated Quantiles and it consists of matching empirical and theoretical functions of quantiles that are informative about the parameters of interest. In the Monte Carlo study we show that MSQ is significantly faster than Maximum Likelihood and the estimates are almost as precise as under MLE. A Value-at-Risk and Expected Shortfall study for 13 years of daily data and for an array of market indexes world-wide shows that the tempered stable estimation with MSQ estimates provides reasonable risk assessments
    • How to create trust in multinational corporations? Cross-cultural contingencies in fair strategy process

      Peeters, Carine; Tackx, Koen (2016)
      This paper proposes a conceptual framework and empirical validation to explain how a culturally differentiated application of the procedural justice theory may enhance the functioning of a multinational corporation (MNC). Using original survey data on 103 managers of international corporations who are strongly involved in headquarter-subsidiary relationships, we study how power distance and individualism-collectivism dimensions of culture moderate the relation between the constituents of procedural justice and the trust subsidiaries have in their headquarters. The analysis suggests that for managers originating from a ‘low power distance’ culture, the perception of changeability in the strategy process has much more impact than for managers stemming from a ‘high power distance’ culture. Also, towards managers with a more ‘collectivist’ background, ensuring that expectations and decisions are clear enhances trust more than for managers with a more ‘individualist’ background.