Robust optimization in distribution-based demand planning: a model for negotiation support

In this paper a model for negotiation support in tactical procurement planning is designed, which is based on a real planning problem from the liquid gas trade sector. The problem is modeled as an assignment problem and transformed into a robust form. Computational experiments using data from a practice partner are presented to demonstrate the effective decision support of our approach.     

Nuclear Waste Management under Approaching Disaster: A Comparison of Decommissioning Strategies for the German Repository Asse II

This article compares different strategies for handling low‐ and medium‐level nuclear waste buried in a retired potassium mine in Germany (Asse II) that faces significant risk of uncontrollable brine intrusion and, hence, long‐term groundwater contamination. We survey the policy process that has resulted in the identification of three possible so‐called decommissioning options: complete backfilling, relocation of the waste to deeper levels in the mine, and retrieval. The selection of a decommissioning strategy must compare expected investment costs with expected social damage costs (economic, environmental, and health damage costs) caused by flooding and subsequent groundwater contamination. We apply a cost minimization approach that accounts for the uncertainty regarding the stability of the rock formation and the risk of an uncontrollable brine intrusion. Since economic and health impacts stretch out into the far future, we examine the impact of different discounting methods and rates. Due to parameter uncertainty, we conduct a sensitivity analysis concerning key assumptions. We find that retrieval, the currently preferred option by policymakers, has the lowest expected social damage costs for low discount rates. However, this advantage is overcompensated by higher expected investment costs. Considering all costs, backfilling is the best option for all discounting scenarios considered.     

The “wrong skewness” problem in stochastic frontier models: A new approach

Stochastic frontier models are widely used to measure, e.g., technical efficiencies of firms. The classical stochastic frontier model often suffers from the empirical artefact that the residuals of the production function may have a positive skewness, whereas a negative one is expected under the model, which leads to estimated full efficiencies of all firms. We propose a new approach to the problem by generalizing the distribution used for the inefficiency variable. This generalized stochastic frontier model allows the sample data to have the wrong skewness while estimating well-defined and nondegenerate efficiency measures. We discuss the statistical properties of the model, and we discuss a test for the symmetry of the error term (no inefficiency). We provide a simulation study to show that our model delivers estimators of efficiency with smaller bias than those of the classical model even if the population skewness has the correct sign. Finally, we apply the model to data of the U.S. textile industry for 1958–2005 and show that for a number of years our model suggests technical efficiencies well below the frontier while the classical one estimates no inefficiency in those years.     

Rota-Risk-Profile-Analysis

Abstract

In this article an update of the Rota-Risk-Profile-Analysis (RRPA) is presented. This RRPA is based on 9 rota-risk criteria that are central to a more encompassing rota theory. The RRPA allows coherent assessment of the physical and social risks of a working-time schedule (rota). comparison of schedules with one another in quantitative terms and interpretations of possible differential effects more adequately. First, a closer look at the instrument-a computer program-is taken. Afterwards the criteria and their way of implementation are discussed briefly. To get an impression of the way that RRPA functions an example will be given by applying the instrument to the working rotas from a study on shiftwork in the Netherlands.     

Modeling Selectivity in Count-Data Models

This article presents a method for modeling endogenous selectivity in count data. As in the case of the switching-regression model, two regimes are distinguished with potentially different data-generating processes. The regime choice is allowed to be correlated with the observed count in each of the regimes. An estimable model is obtained by transforming the underlying processes to the bivariate normal distribution. An empirical application on trip count is provided.     

以后期维特根斯坦为导向探讨宗教理解的语言哲学前提

哈贝马斯主张,为使宗教进入公共领域,必须对它们的文本进行分类和翻译,从而把它们的命题含义与它们的神圣外衣加以分离,以便使它们的意义成为公众可理解的.作者以后期维特根斯坦的哲学为基础进行论证,认为宗教语言不同于科学语言,因为它们涉及不同的生活形式、处理不同的主题,宗教所关心的是对作为整体的世界的生活态度,而科学则对作为物的总和的世界加以说明,因而把宗教的话语翻译成命题的表达方式的做法既无必要也无助益.     

Institutions and Policies for Pro‐poor Agricultural Growth

Global experience with pro‐poor growth and empirical work spanning India, Malawi and Zimbabwe demonstrates the importance of agricultural growth for poverty reduction in poor rural areas, while also pointing to the need for complementary non‐farm sector growth. Theoretical arguments, historical evidence and livelihoods modelling in poor medium‐potential rural economies suggest that, contrary to thinking dominating much of current development policy, subsidies to relieve critical seasonal credit and cash restraints and reduce market and input supply uncertainties need to help in ‘kick‐starting’ agricultural markets if increased smallholder productivity in food‐grains is to drive rural non‐farm growth. Establishing the base conditions for these to work, designing and implementing them to be effective, and then phasing them out are major challenges facing policymakers.     

Collective Labor Supply,Taxes, and Intrahousehold Allocation: An Empirical Approach

ABSTRACT

Most empirical studies of the impact of labor income taxation on the labor supply behavior of households use a unitary modeling approach. In this article, we empirically analyze income taxation and the choice of working hours by combining the collective approach for household behavior and the discrete hours choice framework with fixed costs of work. We identify the sharing rule parameters with data on working hours of both the husband and the wife within a couple. Parameter estimates are used to evaluate various model outcomes, like the wage elasticities of labor supply and the impacts of wage changes on the intrahousehold allocation of income. We also simulate the consequences of a policy change in the tax system. We find that the collective model has different empirical outcomes of income sharing than a restricted model that imposes income pooling. In particular, a specification with income pooling fails to capture asymmetries in the income sharing across spouses. These differences in outcomes have consequences for the evaluation of policy changes in the tax system and shed light on the effectiveness of certain policies.