Suchergebnisse

The aim of my PhD projects is to investigate various problems in applied parametric and nonparametric estimation, and eventually in prediction. The main focus is on welfare analysis. For instance, in both nonparametric density estimation and regression, the so-called boundary effects, i.e. the bias and variance increase due to one-sided data information, can be quite serious. Therefore, a new, straightforward and very simple boundary correction is proposed in the first essay, applying local bandwidth variation at the boundaries. In a comprehensive simulation study this method is shown to perform very well. Furthermore, it is an excellent method for estimating the world income distribution, and Engel curves in economics. In the second and third essays, an integration-based procedure is introduced for estimating and predicting of population distributions. This is done by data matching with applications to the economics of wealth and health. In conclusion, both essays 2 and 3, it is evident that the proposed method can be applied to estimate both (unconditional) discrete and continuous distributions. It is applicable irrespective of the mean regression or model, and can be easily extended to other contexts, such as small area statistics, nonparametric ...

ABSTRACTThe variable‐route vehicle‐refueling problem (VRVRP) is a variant of the network‐flow problem which seeks, for a vehicle traveling from origin s to destination d, both the route and the refueling policy (sequence of fuel stations to use between s and d) that jointly minimize the fuel cost of operating the vehicle. Commercial‐grade decision support systems that solve the VRVRP are widely used by motor carriers, but they provide heuristic solutions only. Exact methods are available from the academic side, but because they focus on minimizing costs, they tend to cut fuel costs in exchange for increased vehicle miles (which can increase fuel consumptions and pollutants emission). We propose a new approach to the VRVRP that allows carriers to jointly seek the two possibly conflicting goals; minimizing fuel cost and vehicle miles. Computational testing shows that our approach (i) outperforms the commercial software products in both goals, and (ii) finds solutions that require significantly less vehicle miles than those given by the exact method proposed in the academic literature, without incurring unacceptable increases in fuel cost.

In many countries the demand for health care services is of increasing importance. Especially in the industrialized world with a changing demographic structure social insurances and politics face real challenges. Reliable predictors of those demand functions will therefore become invaluable tools. This article proposes a prediction method for the distribution of the number of visits to the medical doctor for a determined population, given a sample that is not necessarily taken from that population. It uses the estimated conditional sample distribution, and it can be applied for forecast scenarios. The methods are illustrated along data from Sidney. The introduced methodology can be applied as well to any other prediction problem of discrete distributions in real, future or any fictitious population. It is therefore also an excellent tool for future predictions, scenarios and policy evaluation.

PurposeThis paper aims to adopt the strategy-structure-performance (SSP) framework to explore how proactive social strategy could motivate firms to collaborate with suppliers on social sustainability initiatives, and how such collaborative efforts could unlock a win-win opportunity for both noneconomic (social performance) and economic (operational performance) performance. Additionally, drawing on the tenets of the social exchange theory, the different moderating effects of distributive justice and procedural justice on the social collaboration-performance relationship are also examined.Design/methodology/approachThis study uses survey data collected from 215 manufacturing companies in China. The proposed hypotheses are tested using multiple linear regression models as well as the PROCESS macro within SPSS.FindingsThe results suggest that (1) a proactive social strategy could motivate firms to collaborate with suppliers on joint social activities and (2) social collaboration with suppliers can have a significant positive effect on both social and operational performance. The moderation results suggest that distributive justice has a differential effect on the collaboration-performance link. Particularly, distributive justice strengthens the relationship between social collaboration and operational performance, while it weakens the relationship between social collaboration and social performance. Surprisingly, procedural justice did not have a significant moderating effect on the social collaboration-performance link.Originality/valueThis paper extends the SSP framework to the social sustainability context by not only stressing the importance of proactivity in managing sustainability, but also revealing collaboration as a structural aspect that could achieve superior performance benefits. This study also contributes to sustainable supply chain literature by exploring the moderating roles of justice elements.

PurposeThrough examining the two constructs of inter-organizational complementarity and inter-organizational compatibility in supply chains, the purpose of this paper is to develop a taxonomy of focal firms' inter-organizational fit (IOF) configurations with their suppliers and customers, and examine the relationship between these configurations and environmental innovation (EI) in order to answer the question of "with whom" to collaborate for EI development.Design/methodology/approachA survey instrument was elaborated and data from a sample of 171 US firms were collected. The authors adopted cluster analysis to identify the IOF taxonomy. Canonical discriminant analysis was employed to uncover underlying dimensions between clustering variables and cluster membership. Then, ANOVA tests were conducted to investigate relationships between IOF configurations in the context of EI in supply chains.FindingsThree configurations were identified based on the complementarity and compatibility between focal firms and their supply chain partners. It is observed that the overall IOF level is positively related to firms' EI outcomes. Moreover, inter-organizational complementarity facilitates incremental EI while inter-organizational compatibility plays a more crucial role in radical EI. Both are required to achieve the best innovation outcome.Originality/valueThis research develops the first taxonomy for depicting IOF in a supply chain innovation context and also clarifies different rationale behind the development of incremental and radical EI through examining distinctive effects of the complementarity and compatibility with supply chain partners.

PurposeAdopting the theory of planned behavior, this study attempts to investigate how subjective norms in the supply chain influence a firm's green innovation and how such influences are contingent upon the firm's internal and external factors (i.e. flexibility orientation and environmental dynamism). Two types of subjective norms are examined, i.e. injunctive norms (what supply chain partners say) and descriptive norms (what supply chain partners do).Design/methodology/approachUsing survey data of 178 Chinese small and medium-sized manufacturers, we employ hierarchical linear regression to test the proposed hypotheses.FindingsOur results indicate that both injunctive and descriptive norms are instrumental in stimulating firms to take actions on green innovation. Moreover, the flexibility orientation of a firm can strengthen the effect of descriptive norms. It is also observed that environmental dynamism weakens the efficacy of injunctive norms but strengthens that of descriptive norms on green innovation.Originality/valueThis study is among the first to apply the theory of planned behavior to explain the microfoundations of focal firm's green innovation and distinguish two types of subjective norms in the supply chain. In addition, it extends the theory of planned behavior by revealing internal and external contingent factors (i.e. flexibility orientation and environmental dynamism) of the relationship between subjective norms and firm behaviors.