Workload Control and Order Release: A Lean Solution for Make‐to‐Order Companies

Protecting throughput from variance is the key to achieving lean. Workload control (WLC) accomplishes this in complex make‐to‐order job shops by controlling lead times, capacity, and work‐in‐process (WIP). However, the concept has been dismissed by many authors who believe its order release mechanism reduces the effectiveness of shop floor dispatching and increases work center idleness, thereby also increasing job tardiness results. We show that these problems have been overcome. A WLC order release method known as “LUMS OR” (Lancaster University Management School order release) combines continuous with periodic release, allowing the release of work to be triggered between periodic releases if a work center is starving. This paper refines the method based on the literature (creating “LUMS COR” [Lancaster University Management School corrected order release]) before comparing its performance against the best‐performing purely periodic and continuous release rules across a range of flow directions, from the pure job shop to the general flow shop. Results demonstrate that LUMS COR and the continuous WLC release methods consistently outperform purely periodic release and Constant WIP. LUMS COR is considered the best solution in practice due to its excellent performance and ease of implementation. Findings have significant implications for research and practice: throughput times and job tardiness results can be improved simultaneously and order release and dispatching rules can complement each other. Thus, WLC represents an effective means of implementing lean principles in a make‐to‐order context.     

Shrinking into the big city: influence of genetic and environmental factors on urban dragon lizard morphology and performance capacity

Urban Ecosystems - Urban wildlife faces a novel set of challenges resulting in selective pressure that can lead to population-level changes. We studied Australian water dragons (Intellagama...     

Freezing time? The sociology of egg freezing

In the past decade, social scientists and bioethicists have produced a significant body of work tracking the technical, legal, ethical, and sociocultural development and implications of human egg freezing. What began as a treatment to “preserve” the fertility of cancer patients has transformed into a technology enabling delayed childbearing. We provide an overview of four research areas that have received the most attention in the sociological and anthropological literature of egg freezing: medicalization, gender, temporality and risk, and markets. What emerges from much of the research is the sense that egg freezing has become entangled with cultural imperatives to take future-oriented responsibility for one's own health, financial, social, and reproductive needs through self-management, risk reduction, calculation, and optimization. Throughout, we consider the implications of this novel reproductive technology within national and transnational “reproflows” that stratify reproduction along raced and classed lines.     

Marital status and generalized trust in other people: A population-based study

The association between marital status and generalized trust in other people was investigated. The public health survey in Skåne 2008 is a cross-sectional study including 28,198 persons (55% participation rate) aged 18–80 in southern Sweden. Logistic regression models investigated associations between marital status and trust, adjusting for age, country of birth, education, emotional support, instrumental support and economic stress. 33.9% of the men and 35.7% of the women had low trust. The significantly higher odds ratios of low trust for unmarried men and women and divorced men remained throughout the analyses, while the significant association disappeared for divorced women in the final model. In contrast, the odds ratios of low trust for widows/widowers remained not significant compared to the married/cohabitating category throughout the analyses.     

Why does myopia decrease the willingness to invest? Is it myopic loss aversion or myopic loss probability aversion?

For loss averse investors, a sequence of risky investments looks less attractive if it is evaluated myopically—an effect called myopic loss aversion (MLA). The consequences of this effect have been confirmed in several experiments and its robustness is largely undisputed. The effect’s causes, however, have not been thoroughly examined with regard to one important aspect. Due to the construction of the lotteries that were used in the experiments, none of the studies is able to distinguish between MLA and an explanation based on (myopic) loss probability aversion (MLPA). This distinction is important, however, in discussion of the practical relevance and the generalizability of the phenomenon. We designed an experiment that is able to disentangle lottery attractiveness and loss probabilities. Our analysis reveals that mere loss probabilities are not as important in this dynamic context as previous findings in other domains suggest. The results favor the MLA over the MLPA explanation.     

Common Learning

Consider two agents who learn the value of an unknown parameter by observing a sequence of private signals. The signals are independent and identically distributed across time but not necessarily across agents. We show that when each agent's signal space is finite, the agents will commonly learn the value of the parameter, that is, that the true value of the parameter will become approximate common knowledge. The essential step in this argument is to express the expectation of one agent's signals, conditional on those of the other agent, in terms of a Markov chain. This allows us to invoke a contraction mapping principle ensuring that if one agent's signals are close to those expected under a particular value of the parameter, then that agent expects the other agent's signals to be even closer to those expected under the parameter value. In contrast, if the agents' observations come from a countably infinite signal space, then this contraction mapping property fails. We show by example that common learning can fail in this case.     

Global operations strategy: Coordinating manufacturing networks

This paper presents a concept that describes how companies can manage their international operations so as to facilitate the coordination of their manufacturing networks. The research presented originates from a model that was developed at the Swedish telecommunications company Ericsson in the mid-1990s, but has since then been further elaborated. More specifically, the purpose of this paper is to show how Ericsson Radio Systems incorporated the recent research on manufacturing networks found in literature in their global operations strategy, and to present the conceptual model that was the result of these efforts. The conceptual model described in this paper focuses on the blending of cost competitiveness, flexibility, and innovativeness; a combination termed the “transnational solution” in the literature. In addition to a literature review on manufacturing networks and global operations and the proposed conceptual model, the paper also contains a case illustration showing how Ericsson has implemented a version of the conceptual model so that their global operations strategy realizes the transnational solution.     

PARTY FORMATION IN SINGLE‐ISSUE POLITICS

We study the implications of economies of party size in a model of party formation. We show that when the policy space is one‐dimensional, candidates form at most two parties. This result does not depend on the magnitude of the economies of party size or sensitively on the nature of the individuals' preferences. It does depend on our assumptions that the policy space is one‐dimensional and that uncertainty is absent; we study how modifications of these assumptions affect our conclusions. (JEL: D70, D72)