Load-Oriented Order Release (LOOR) revisited: bringing it back to the state of the art

In the workload control literature, the Load-Oriented Order Release (LOOR) approach has been neglected since its robustness was questioned at the end of the 1990s. This paper revisits LOOR and evaluates whether its performance can be improved in two ways. First, an intermediate pull release mechanism is added to avoid starvation between periodic release events. This mechanism was recently shown to be effective at improving the performance of a state-of-the-art release method known as LUMS COR. Second, an integer linear programming model is used to manage the trade-off between the timing and load balancing functions of order release. The two refinements are assessed using simulations of different shop configurations, which allow us to evaluate robustness. Results demonstrate that the refinements contribute to improving the performance of LOOR such that it can even outperform LUMS COR. Perhaps counter-intuitively, putting more emphasis on load balancing than on the urgency of individual orders is shown to lead to a lower percentage of tardy orders. Overall, the improvements mean that concerns about LOOR’s robustness are no longer valid – it now appears suitable for a wide range of shops found in practice.     

Learning discrete decomposable graphical models via constraint optimization

Statistical model learning problems are traditionally solved using either heuristic greedy optimization or stochastic simulation, such as Markov chain Monte Carlo or simulated annealing. Recently, there has been an increasing interest in the use of combinatorial search methods, including those based on computational logic. Some of these methods are particularly attractive since they can also be successful in proving the global optimality of solutions, in contrast to stochastic algorithms that only guarantee optimality at the limit. Here we improve and generalize a recently introduced constraint-based method for learning undirected graphical models. The new method combines perfect elimination orderings with various strategies for solution pruning and offers a dramatic improvement both in terms of time and memory complexity. We also show that the method is capable of efficiently handling a more general class of models, called stratified/labeled graphical models, which have an astronomically larger model space.     

Introvision in der Arbeitsvermittlung für Fallmanager und Arbeitslose

In the context of a pilot study the effects of the educational-psychological intervention Introvision were tested with older long-term unemployed people. The project was accomplished in the time by 1.4.2010 to 31.12.2010 in co-operation between ARGE Paderborn and the research group Introvision. In the context of the project 16 employees of ARGE Paderborn participated in an advanced training to Introvision, 31 customers of ARGE Paderborn began a coaching to get introduction in Introvision and 20 have also finished. Nine customers decided to participate five individual coachings. The results show, that the offers have a high individual use for the participants. To the central changes belong improved handling of stress, decrease of social isolation, improved (self-) perception as well as a higher self-confidence and a more open co-operation between customers and employees of ARGE Paderborn. Besides four participation began a job on the first labour market and two could be connected to a honorary activity.     

Emotional Transactions in the Paris Subway: Combining Naturalistic Videotaping,Objective Facial Coding and Sequential Analysis in the Study of Nonverbal Emotional Behavior

We report on what, to our knowledge, represents the first study of nonverbal emotional behavior in crowded public places combining naturalistic videotaping of situated activity, objective coding of facial movement, and sequential analysis of behavior. In the first part of the study we argue that passengers do not lose emotional sensitivity to physical contact as density (passengers per square meter) increases, which indicates that physical contact is experienced as a territorial intrusion regardless of crowdedness. In the second part of the study, we suggest that passengers resolve the emotions due to intrusive physical contacts through two interactional strategies involving facial movements usually interpreted as “expressions of emotions.” Since proxemic violations seem to represent a pervasive emotion elicitor, the protocol can be extended to other means of transportation and replicated in other locations. We conclude that the methodology provides an effective tool for theory-building in the study of nonverbal emotional behavior.     

The effects of state-dependent human behavior on the design of a serial line

Most research on line design assumes that human operators perform independently from the status of the line. Recent empirical evidence is contradictory. Humans are likely to change their working speed if they might otherwise cause idle time (Schultz et al., Manage Sci 44(12):1595–1607, 1998). This peculiarity of worker behavior is observed in a variety of settings but little is still known about optimal line design that accounts for this more realistic modeling of worker behavior. Therefore, we analyze work allocation in a serial line with limited buffer capacity and adaptive human behavior. An extensive simulation study reveals that optimal work allocation in state-dependent models is different from classical state-independent models. A bowl-shaped work allocation might be suboptimal and design guidelines are more complicated. Depending on the extent of human reactions, a bowl-shaped, balanced, or reversed-bowl work allocation can be preferable.     

Impacts of urban sprawl on species richness of plants,butterflies, gastropods and birds: not only built-up area matters

Urban growth is a major factor of global environmental change and has important impacts on biodiversity, such as changes in species composition and biotic homogenization. Most previous studies have focused on effects of urban area as a general measure of urbanization, and on few or single taxa. Here, we analyzed the impacts of the different components of urban sprawl (i.e., scattered and widespread urban growth) on species richness of a variety of taxonomic groups covering mosses, vascular plants, gastropods, butterflies, and birds at the habitat and landscape scales. Besides urban area, we considered the average age, imperviousness, and dispersion degree of urban area, along with human population density, to disentangle the effects of the different components of urban sprawl on biodiversity. The study was carried out in the Swiss Plateau that has undergone substantial urban sprawl in recent decades.Vascular plants and birds showed the strongest responses to urban sprawl, especially at the landscape scale, with non-native and ruderal plants proliferating and common generalist birds increasing at the expense of specialist birds as urban sprawl grew. Overall, urban area had the greatest contribution on such impacts, but additional effects of urban dispersion (i.e., increase of non-native plants) and human population density (i.e., increases of ruderal plants and common generalist birds) were found. Our findings support the hypothesis that negative impacts of urban sprawl on biodiversity can be reduced by compacting urban growth while still avoiding the formation of very densely populated areas.     

Exploring the nonverbal facet of ethnic discrimination: a field experiment on anti-Roma racism in the Paris métro

A field experiment on the discrimination of Roma migrants from Eastern Europe was conducted in two stations of the Paris metro to explore the behaviors that may communicate misrecognition in everyday encounters. An actress asked for help to randomly chosen passengers on a metro platform, wearing a glaringly Romani skirt in the treatment condition but an unconspicuous middle-class style in the control condition. In interaction with the actress wearing the Romani skirt, passengers were found to enact the so-called “visual dominance pattern”, and male passengers in particular were found to keep greater distances. Reverse discrimination also occurred as women kept shorter distances from the actress bearing the ethnic stigma. Last, passengers helped less the stigmatized actress, but only in one of the two metro stations where trials were conducted.     

Academic economists behaving badly? A survey on three areas of unethical behavior

This article measures the degree to which academic economists have engaged in unethical behavior and the degree to which academic economists believe the profession as a whole engages in unethical behavior. Three main types of unethical behavior are examined: (1) falsification of research; (2) expropriation of graduate student research or including an undeserving co-author on a research paper; and (3) exchange of grades for gifts, money, or sex. Using a unique data set gathered at the 1998 American Economic Association (AEA) meetings, we find that there is a significant amount of misconduct, particularly in the second category.     

Public Support for Sickle-Cell Disease Funding: Does Race Matter?

Despite the fact that sickle-cell disease (SCD) is perhaps the most “racialized” medical condition in the USA, very little is known about how “race” impacts public support for health policies related to the condition. We embedded an experiment within the 2011 Cooperative Congressional Election Study in order to assess perceptions about SCD among 1250 participants from diverse backgrounds and evaluate the extent to which these perceptions were associated with support for government spending on SCD-related benefits. We manipulated the racial phenotype of SCD advocates who requested additional government funding and asked participants to indicate how much the government should provide. Overall, participants expressed moderately positive attitudes about SCD, and there were no differences in funding support based on the race of the advocate. However, white participants supported less funding compared to nonwhite participants, even after adjusting for a number of demographic and attitudinal covariates. These findings suggest that a complex relationship between racial identification and implicit racism may shape public perceptions about SCD that negatively influences perceivers’ support for SCD-related policy.