Notes and Communications REPLANNING FREQUENCIES FOR MASTER PRODUCTION SCHEDULES

Updating production plans typically is achieved by rolling the planning horizon forward one period at a time, each time including the latest information in order to determine the best course of action to pursue in the present period. Theoretical planning-horizon studies have identified the conditions by which the production decisions in the current and some specified number of future periods remain optimal given some set of future demands. Motivated by these findings, this study addresses the replanning frequency in a hierarchical production planning problem where no planning-horizon theorems are available. In this problem the aggregate production plan and the master production schedule are linked by a rolling-horizon practice. Empirical experimentation indicates that under certain cost and demand conditions the master production schedule need not be updated every period. If a schedule does not need to be updated for several periods, the schedule for these periods can be frozen to provide stability for planning components at lower levels in the bill of material of the products. The results of this study thus provide some reference for the determination of the frozen portion of the master production schedule.     

Gender inequality in the one percent: A look under the hood of high incomes in Germany

Gender differences in economic outcomes are important topics in social science research. However, the study of gender differences among economic elites—“the top one percent”—has received surprisingly little attention, likely also due to a lack of empirical data. This paper investigates gender differences in individual and household income among the top one percent of individual monthly net incomes and top two percent of net household incomes using data from the German Microcensus from 2006 to 2016 covering more than 3.3 million individuals. I find that women account for only around 14% of the one percent in individual incomes. Additionally, regarding the household level, women's incomes are sufficient to achieve two percent status in fewer than 10% of all households. Both numbers did hardly change over the decade from 2006 to 2016. Furthermore, women's pathways to belonging to a high-income household are far more dependent on their partner's education and employment status than men's. Overall, the findings thus show dramatic gender differences among the German economic elite that do not narrow over time.     

The Imperial Origins of Nation-States: Revisiting Hannah Arendt's Genealogy of Totalitarianism1

Against the backdrop of World War II, Hannah Arendt explores the origins of totalitarian rule, arguing that they date back to as early as the late nineteenth century. Alongside anti-Semitism, overseas colonialism and pan-nationalism paved the way for the totalitarian regimes that crystallized a few decades later by weakening the system of nation-states from within. Using the example of Germany, I will argue in this article that we need to revise Arendt's narrative. It focuses too narrowly on how nationalism turned into its categorical opposite, imperialism, neglecting the complementary dynamics of how empire facilitated the nation-state. Only then can we acknowledge the deep rupture that World War I brought about when it created in its wake a dynamic that culminated in the destruction of European nation-states.     

Child welfare policy and services in Korea

Over the past 20 years, the Korean government has developed child welfare laws to respond to an increasing number of child maltreatment cases and create a centralized child welfare delivery system. However, the system remains fragmented and under-developed due to a lack of understanding of child maltreatment and limited government support. Further, few studies have comprehensively reviewed the system. This study examines the Korean child welfare system, identifies challenges for child welfare policies and services, and discusses the implications for future policy; the results can be used to improve the safety, permanency, and well-being of children and families in Korea. The analysis shows that the government has prioritized family preservation over removal from families, even in substantiated cases of abuse. However, ensuring the safety of children in Korea will require not only working to preserve families but also developing and implementing better options for in-home services and out-of-home placement.     

Robustly assigning unstable items

Journal of Combinatorial Optimization - We study the robust assignment problem where the goal is to assign items of various types to containers without exceeding container capacity. We seek an...