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.     

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.     

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.     

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)     

A decision support tool for planning bills-of-material

In this paper, the framework for a decision support tool for planning bills-of-material is presented. This tool generates a set of modular planning bills-of-material from the manufacturing bills-of-material for a company. The tool attempts to consolidate options in a product family which are specific. The force with which the tool attempts to consolidate two or more options is dependent on the financial control parameters. As well as having a minimum amount of common material, the financial value of such a match must also be of sufficiently high value to be worth planning together. The tool also examines the long-term inventory effect of planning two or more options as common.     

UNDERSTANDING ATTITUDES TOWARD PROGRESSIVE TAXATION

This article examines attitudes toward and understanding ofprogressive taxation by comparing subjects' choices of fairtax rate structures in response to questions framed in bothabstract and concrete terms. Consistent with surveys of thegeneral public, a majority of the subjects indicated a preferencefor progressive taxation in response to abstract questions.However, consistent with results from social psychology andpolitical science research, the subjects' preferences for progressivetaxation were significantly different (lower) in response toconcrete questions. The observed preference reversal betweenprogressive taxes in the abstract and flat taxes (i.e., proportionalto income) in concrete situations is hypothesized to be associatedwith subjects' ignorance (their lack of understanding of theabstract concept of progressive taxation). Thus, between-subjectstests are conducted to examine (1)differences in order effectsof the abstract and concrete frames that might cue the subjectsto a greater understanding of the abstract terms, (2) the effectsof definitions and illustrations on subjects' choices, and (3)the use of different scales and reference points to measureresponses. Consistent results (preference reversals from preferencesfor progressivity in the abstract to nonprogressive preferencesin concrete frames) were obtained across all of the between-subjectsexperimental manipulations. A within-subjects design also includesa posttest knowledge test that demonstrates the tendency ofa majority of subjects to misidentify concrete comparisons asprogressive when they actually are regressive. Subjects whowere able to correctly identify the concrete comparisons weremore likely to be consistent in their responses to abstractand concrete frames. However, 36 percent of these "knowledgeable"subjects still preferred progressive taxes in the abstract butflat or regressive taxes in the concrete situations. These resultsraise concerns about conclusions from public opinion polls usingabstract questions regarding preferences for progressive taxrates.     

Who Owns Democracy?: Explaining the Long‐running Debate over Canadian/American Value Differences*

Depuis un certain temps, Seymour Martin Lipset et bon nombre de théoriciens canadiens anglais débattent de la question des différences entre les valeurs canadiennes et américaines. Ce que personne n'a encore jamais demandé est pourquoi ce débat se poursuit‐il après toutes ces années. L'auteur propose ici que la longévité de ce débat découle principalement du fait qu'il est alimenté par des affirmations idéologiques rivales et insolubles implicites dans les arguments avancés de part et d'autre. Corame première étape de la démonstration de cette idée, il met en évidence les facons selon lesquelles le débat entre Lipset et ses critiques aurait pu se dérouler vraiment différemment si les préoccupations exprimées par les participants – la comparaison des cultures canadienne et américaine et l'évaluation des effets qui se continuent de la révolution américaine – avaient véritablement été celles suscitant le débat. Enfin, l'auteur cerne la nature précise de ces affirmations idéologiques implicites. Dans les deux cas, il soutient qu'elles reviennent à discuter de « qui détient la meilleure forme de démocratic ». For some time now, Seymour Martin Lipset and a variety of English‐Canadian academics have debated the issue of Canadian/American value differences. However, no one has yet asked why this debate is still ongoing. This article suggests that its longevity is mainly fuelled by competing and irresolvable ideological claims implicit in the arguments put forward by each side. It points to the ways in which the debate between Lipset and his critics might have proceeded quite differently if the participants' stated concerns–i.e., comparing the Canadian and American cultures; assessing the continuing cultural effects of the American Revolution–had truly been those fuelling the debate. The final section identifies the precise nature of the implicit ideological claims being advanced. In both cases, I argue, these claims are about “who owns the best sort of democracy.”