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Waltman RE 《Medical economics》2000,77(2):159-60, 163-4, 166
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This paper discusses the issue of integrating various decision levels in hierarchical production planning systems. First the theory is briefly reviewed and then two case studies are presented. It is argued that it is not sufficient to have a good decision model at every level of the decision hierarchy. The different models should be carefully integrated. The potential problems resulting from a lack of integration are discussed. These problems are then illustrated in two case studies in order to be able to focus on actual managerial issues. It is shown how different decision levels supported by decision models were integrated in these two applications. Two important features are the crucial role of crossfunctional managerial committees in the integration process and the introduction of slack to avoid disaggregation problems.We do not claim to be exhaustive in presenting the problems related to integration nor do we claim that the solutions to the cases are the best possible ones. We do, however, hope that this paper motivates production managers to take a serious look at their hierarchical planning procedures. 相似文献
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Ludo Peeters Eloi Schreurs Steven Van Passel 《Environmental and Resource Economics》2017,66(1):135-168
We estimate a hedonic-pricing model using geo-coded farmland-transaction data from the Campine region, situated in the north-east of Belgium. Unlike previous hedonic studies, we use the method of unconditional quantile regression (Firpo et al., in Econometrica 77(3):953–973, 2009). An important advantage of this new method over the traditional conditional quantile regression (Koenker and Bassett, in Econometrica 46(1):33–50, 1978) is that it allows for the estimation of potentially heterogeneous effects of cadmium pollution along the entire (unconditional) distribution of farmland prices. Using a threshold specification of the hedonic-pricing model, we find evidence of a U-shaped valuation pattern, where cadmium pollution of the soil has a negative and significant impact on prices only in the middle range of the distribution, insofar as cadmium concentrations are above the regulatory standard of 2 parts per million for agricultural land. Results obtained from a probit model to classify land plots into different price segments further suggest that the heterogeneous impact of soil pollution on price can be directly related to the variety of amenities that farmland provides. 相似文献
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Waltman RE 《Medical economics》2002,79(1):67, 71-67, 72
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Ludo Waltman Nees Jan van Eck Rommert Dekker Uzay Kaymak 《Journal of Evolutionary Economics》2011,21(5):737-756
We are concerned with evolutionary algorithms that are employed for economic modeling purposes. We focus in particular on
evolutionary algorithms that use a binary encoding of strategies. These algorithms, commonly referred to as genetic algorithms,
are popular in agent-based computational economics research. In many studies, however, there is no clear reason for the use
of a binary encoding of strategies. We therefore examine to what extent the use of such an encoding may influence the results
produced by an evolutionary algorithm. It turns out that the use of a binary encoding can have quite significant effects.
Since these effects do not have a meaningful economic interpretation, they should be regarded as artifacts. Our findings indicate
that in general the use of a binary encoding is undesirable. They also highlight the importance of employing evolutionary
algorithms with a sensible economic interpretation. 相似文献