Determination of an order-up-to policy in the stochastic economic lot scheduling model

We consider a production–inventory problem with compound renewal item demand. The model consists of stockpoints, one for each item, controlled according to (R,S)-policies and one machine which replenishes them. The replenishment orders are produced with a fixed rate on the machine with significant setup times and costs, which are stochastic and sequence dependent. The time between the release and the production of the replenishment order is called the waiting time. We develop analytical approximations for the first two moments of this waiting time, the order-up-to levels and the average physical inventory levels for all stockpoints, given the target fill rates. These analytical approximations allows for a quick evaluation of the waiting time which is important when optimization of the system is considered.     

Poverty or prosperity in northern India? New evidence on real wages, 1590s–1870s†

This article introduces a new dataset on wages in northern India (from Gujarat in the west to Bengal in the east) from the 1590s to the 1870s. It follows Allen's subsistence basket methodology to compute internationally comparable real wages to shed light on developments in Indian living standards over time. It adjusts the comparative cost-of-living indices to take into account differences in climate and caloric intake due to variances in heights. The article also discusses the male/female wage gap in northern India. It demonstrates that the ‘great divergence’ started in the late seventeenth century, and widened further after the 1720s and especially after the 1800s. It was subsequently primarily England's spurt and India's stagnation in the first half of the nineteenth century that brought about most serious differences in the standard of living. If the British colonial state is to blame—as often suggested by the literature on India's persistent poverty—the fault lies in its failure to improve the situation after the British became near-undisputed masters of India in 1820.     

On the accuracy of phase-type approximations of heavy-tailed risk models

Numerical evaluation of ruin probabilities in the classical risk model is an important problem. If claim sizes are heavy-tailed, then such evaluations are challenging. To overcome this, an attractive way is to approximate the claim sizes with a phase-type distribution. What is not clear though is how many phases are enough in order to achieve a specific accuracy in the approximation of the ruin probability. The goals of this paper are to investigate the number of phases required so that we can achieve a pre-specified accuracy for the ruin probability and to provide error bounds. Also, in the special case of a completely monotone claim size distribution we develop an algorithm to estimate the ruin probability by approximating the excess claim size distribution with a hyperexponential one. Finally, we compare our approximation with the heavy traffic and heavy tail approximations.     

Collection of recyclables from cubes – A case study

Collection of recyclable materials is a major part of reverse logistics and an important issue in sustainable logistics. In this paper we consider a case study where paper and glass are collected from recycling cubes and transported to a treatment facility and processed for reuse. We show how outsourcing the planning and transportation of this service may result in conflicts of interest and unsustainable solutions. Finally, we suggest an alternative payment structure which can lead to a common goal, overall financial sustainability, and an improved financial situation for both the public company and the logistics provider.     

Does immigrant employment matter for export sales? Evidence from Denmark

Immigration impacts on the economy in ample ways: it affects growth, wages and total factor productivity. This study deals with the effects of immigration on firm exports. Can firms benefit from hiring immigrants to expand their export sales? Or do immigrants who live in the firm’s region affect trade? In contrast to the existing literature, we are able to distinguish these two distinct channels. Using matched employer-employee data from Denmark for the years 1995–2005, we provide novel insights in the nexus between exports and immigration. We further contribute to the literature by providing first evidence on the adjustment of firms’ product portfolio in response to immigration. Our empirical results are consistent with the claim that immigration lowers barriers to trade. Both, regional immigration and foreign employment matter for the composition of firm-level exports. As a novel insight, our findings suggest that firms benefit from immigration in terms of expanded export sales, when they hire foreign employees. We only find weak evidence for the local presence of foreigners to increase export sales, which we ascribe to the conjecture that at least some trade-cost reducing forces of immigration like for example intercultural knowledge or personal and business networks abroad, can only be accessed or exploited via foreign employment.     

Enhancing the Credibility of Reporting on Corporate Social Responsibility in Europe

This paper studies variables that have an effect on the choice of whether or not reports on corporate social responsibility are assured and who is selected to provide assurance. Such assurance reports increase the credibility of environmental and social reporting. In a European sample we observe some differences from previous research. Overall, industry effects seem small, but size and media visibility have a significant impact on assuring CSR reports. It seems that companies differentiate less between auditors and consultants. Copyright © 2013 John Wiley & Sons, Ltd and ERP Environment     

How much work?

The future of work is a constant topic of discussion. This article approaches it with the deceptively simple notion of demand and supply: how much work is required to yield a reasonable standard of living? And how much work would people prefer to put in? Answers are given from two studies of a mature Welfare State, Sweden. The answers also point to the following underlying questions: What are the driving forces behind the present pattern of work? Is there a lagging self-understanding about needs, risks and possibilities in our type of society?     

Optimal regulation of lumpy investments

We study optimal timing of regulated investment in a real options setting, in which the regulated monopolist has private information on investment costs. In solving the ensuing agency problem, the regulator trades off investment timing inefficiency against the dead-weight loss arising from high price caps. We show that optimal regulation is implemented by a price cap that decreases as a function of the monopolist’s chosen investment time.     

PRODUCT CHARACTERISTICS AND ARBITRAGE IN THE AUSTRALIAN AND NEW ZEALAND WOOL MARKETS*

The physical characteristics of wool are important determinants of its spinning properties, yarn quality and end use. The degree to which wools from different countries of origin may be substituted has important implications for the domestic marketing policies of Australia and New Zealand. The hypothesis examined in this paper is that the differences in wool prices can be explained by differences in the physical characteristics of the wool and that objective measures of these characteristics allow for effective arbitrage between these markets. The alternative hypothesis is that premiums or discounts exist owing to country of origin. A hedonic price analysis was conducted on wool prices in Australia and New Zealand using a balanced sample of sale lot data from the 1986-87 selling season. In the year examined, there was no evidence of any price premiums associated with country of origin.     

The Export Promoting Effect of Emigration: Evidence from Denmark

Ethnic networks exhibit the potential to lower barriers to trade. The paper identifies the export‐promoting effect of emigration on the firm‐level using Danish data for the year 2001. Accounting for taste similarity, self‐selection and unobserved heterogeneity, three main findings are established. First, the elasticity of manufacturing exports to emigration is robust and of similar size as the effect of immigration. Secondly, only immigration encourages market entry but not emigration, suggesting that variable cost reductions and demand for home‐country products are the driving force of emigrant network effects. Thirdly, benefits from emigration accrue exclusively to low‐productivity firms.