MIXED ASSEMBLY AND DISASSEMBLY OPERATIONS FOR REMANUFACTURING

In this paper we consider the problem of designing a mixed assembly‐disassembly line for remanufacturing. That is, parts from the disassembly and repair of used products can be used to build “new” products. This is a problem common to many OEM remanufacturers, such as Xerox or Kodak. We study two main configurations, under the assumption that the disassembly sequence is exactly the reverse of the assembly sequence. Under a parallel configuration, there exist two separate dedicated lines, one for assembly and one for disassembly, which are decoupled by buffers—from both disassembly operations, which have preference, as well as parts from an outside, perfectly reliable supplier. Under a mixed configuration, the same station is used for both disassembly and assembly of a specific part. The problem is studied using GI/G/c networks, as well as simulation. Due to a loss of pooling, we conclude that the parallel configuration outperforms the mixed line only when the variability of both arrivals and processing time are significantly higher for disassembly and remanufacturing than for assembly. Via a simulation, we explore the impact of having advanced yield information for the remanufacturing parts. We find that advanced yield information generally improves flow times; however, there are some instances where it lengthens flow times.     

Migrants as strategic actors in the European Union's Global Approach to Migration and Mobility

The European Union's discourse of ‘partnership’ in the Global Approach to Migration and Mobility and the widely expressed critique of this discourse as a process of ‘externalization’ of EU policy both depend on unitary accounts of the main policy actors involved. Two separate literatures contest such unitary accounts. Within political science and international relations, institutional approaches identify a range of strategic actors involved in policy development; in anthropology, there is a well‐established interest in the strategic behaviour of disempowered actors. In this article, I set out to link these two approaches with an examination of undocumented migrants as strategic actors. I use a case study of events at the borders between Morocco and the Spanish enclaves of Ceuta and Melilla in late 2005, which have proved extremely influential in the continued development of the EU's global approach, to identify the ways in which even highly marginalized migrants were able to develop transnational social organizations.     

CAPACITY AND PRODUCTION DECISIONS IN STOCHASTIC MANUFACTURING SYSTEMS: AN ASYMPTOTIC OPTIMAL HIERARCHICAL APPROACH

We present a new paradigm of hierarchical decision making in production planning and capacity expansion problems under uncertainty. We show that under reasonable assumptions, the strategic level management can base the capacity decision on aggregated information from the shopfloor, and the operational level management, given this decision, can derive a production plan for the system, without too large a loss in optimality when compared to simultaneous determination of optimal capacity and production decisions. The results are obtained via an asymptotic analysis of a manufacturing system with convex costs, constant demand, and with machines subject to random breakdown and repair. The decision variables are purchase time of a new machine at a given fixed cost and production plans before and after the purchase. The objective is to minimize the discounted costs of investment, production, inventories, and backlogs. If the rate of change in machine states such as up and down is assumed to be much larger than the rate of discounting costs, one obtains a simpler limiting problem in which the random capacity is replaced by its mean. We develop methods for constructing asymptotically optimal decisions for the original problem from the optimal decisions for the limiting problem. We obtain error estimates for these constructed decisions.     

LEAN AND GREEN? AN EMPIRICAL EXAMINATION OF THE RELATIONSHIP BETWEEN LEAN PRODUCTION AND ENVIRONMENTAL PERFORMANCE

Lean production may have a significant public good spillover—improved environmental performance. However, empirical evidence of the link between lean production practices and environmental performance has not resolved the nature of the relationship. To explore this issue, we conduct an empirical analysis of the environmental performance of 17,499 U.S. manufacturing establishments during the time period 1991–1996. We find that those establishments that adopt the quality management standard ISO 9000 are more likely to adopt the environmental management standard ISO 14000. We also find strong evidence that lean production, as measured by ISO 9000 adoption and low chemical inventories, is complementary to waste reduction and pollution reduction.     

On the Contingent Valuation of Safety and the Safety of Contingent Valuation: Part 1-Caveat Investigator

This article reports the results of two studies aimed at testing and refining a procedure for estimating willingness-to-pay based monetary values of safety using the contingent valuation method. In spite of the fact that respondents were given the opportunity to discuss various safety issues and key concepts in focus group meetings held in advance of individual interviews, and were also given ample opportunity to revise their responses in the light of the overall pattern of these responses, the results show clear evidence of extensive and persistent insensitivity to the scale and scope of the safety improvements that were specified in the contingent valuation questions, as well as vulnerability to framing effects. This clearly casts serious doubt on the reliability and validity of willingness-to-pay based monetary values of safety estimated using conventional contingent valuation procedures.     

Community Work: Social Realities and Ethical Dilemmas

Summary This article reviews the contributions of sociology and politicalsciences to the understanding of communities and relates theseto some of the key problems facing community workers. It suggeststhat an effective assessment of some of the ethical dilemmasfacing community workers must be based upon a cool appraisalof those urban social structures which are commonly and largelymisleadingly regarded as communities     

EXPERTS AND THEIR RECORDS

A market where short‐lived customers interact with long‐lived experts is considered. Experts privately observe which treatment best serves a customer, but are free to choose more or less profitable treatments. Customers only observe records of experts' past actions. If experts are homogeneous there exists an equilibrium where experts always choose the customer's preferred treatment (play truthfully). Experts are incentivized with the promise of future business: new customers tend to choose experts who performed less profitable treatments in the past. If expert payoffs are private information, experts can never always be truthful. But sufficiently patient experts may be truthful almost always. (JEL C73, D82)     

LABOR SUPPLY DIFFERENCES BETWEEN MARRIED HETEROSEXUAL WOMEN AND PARTNERED LESBIANS: A SEMI‐PARAMETRIC DECOMPOSITION APPROACH

Using 2000 U.S. Census data we illustrate the importance of accounting for household specialization in lesbian couples when examining labor supply differences between heterosexual married and partnered lesbian women. Specifically, we find the labor supply gap is substantially larger between married women and partnered lesbian women who specialize in market production (primary earners) than between married women and partnered lesbian women who specialize in household production (secondary earners). Applying a semi‐parametric decomposition approach we show that controlling for children significantly reduces the gap between married women and secondary lesbian earners both in terms of the decision to remain attached to the labor market (the extensive margin) and annual hours of work conditional on working (the intensive margin). Further, the effect of controlling for children primarily reduces the percentage of secondary lesbian earners working extremely high annual hours. (JEL J15, J16, J22)