A Stabilized Structured Dantzig-Wolfe Decomposition Method

We discuss an algorithmic scheme, which we call the stabilized structured Dantzig-Wolfe decomposition method, for solving large-scale structured linear programs. It can be applied when the subproblem of the standard Dantzig-Wolfe approach admits an alternative master model amenable to column generation, other than the standard one in which there is a variable for each of the extreme points and extreme rays of the corresponding polyhedron. Stabilization is achieved by the same techniques developed for the standard Dantzig-Wolfe approach and it is equally useful to improve the performance, as shown by computational results obtained on an application to the multicommodity capacitated network design problem

Avoiding unnecessary demerging and remerging of multi‐commodity integer flows

Resource flows may merge and demerge at a network node. Sometimes several demerged flows may be immediately merged again, but in different combinations compared to before they were demerged. However, the demerging is unnecessary in the first place if the total resources at each of the network nodes involved remains unchanged. We describe this situation as “unnecessary demerging and remerging (UDR)” of flows, which would incur unnecessary operations and costs in practice. Multi‐commodity integer flows in particular will be considered in this paper. This deficiency could be theoretically overcome by means of fixed‐charge variables, but the practicality of this approach is restricted by the difficulty in solving the corresponding integer linear program (ILP). Moreover, in a problem where the objective function has many cost elements, it would be helpful if such operational costs are optimized implicitly. This paper presents a heuristic branching method within an ILP solver for removing UDR without the use of fixed‐charge variables. We use the concept of “flow potentials” (different from “flow residues” for max‐flows) guided by which underutilized arcs are heuristically banned, thus reducing occurrences of UDR. Flow connection bigraphs and flow connection groups (FCGs) are introduced. We prove that if certain conditions are met, fully utilizing an arc will guarantee an improvement within an FCG. Moreover, a location sub‐model is given when the former cannot guarantee an improvement. More importantly, the heuristic approach can significantly enhance the full fixed‐charge model by warm‐starting. Computational experiments based on real‐world instances have shown the usefulness of the proposed methods

Austérité et gestion dans les universités québécoises: une analyse des perceptions de directeurs de département

This article discusses different aspects of the management of budgetary austerity in higher education. Its database consists of in-depth interviews with twenty-five department chairpersons from six Québec universities. In general, strategic choices imposed by university administration are reactive and aimed at meeting short-term government objectives. Among the strategies more dependent on departmental choice, some are proactive. Nevertheless, the range of choices is limited by overall constraints. Longer term solutions to cope with the crisis in higher education proposed by chairpersons are problematic since they stem from somewhat contradictory views on the major role of the university as an institution.Cet article présente différents aspects de la gestion de l'austérité budgétaire dans l'enseignement supérieur à partir d'entrevues en profondeur effectuées auprès de vingt-cinq directeurs de département de six universités québécoises. En général, il apparaît que les mesures imposées par la direction de l'Université pour faire face aux compressions budgétaires sont plutôt réactives et visent à rencontrer à court terme les objectifs gouvernementaux. Parmi les stratégies relevant plus directement des choix des départements, quelques unes sont proactives. Le poids des contraintes limite, cependant, les choix. Les solutions à plus long terme proposées par les directeurs pour surmonter la crise actuelle de l'enseignement supérieur sont problématiques car elles se basent sur des visions contradictoires de la mission institutionnelle de l'université

The role of language in the experience and perception of emotion: a neuroimaging meta-analysis

Recent behavioral and neuroimaging studies demonstrate that labeling one’s emotional experiences and perceptions alters those states. Here, we used a comprehensive meta-analysis of the neuroimaging literature to systematically explore whether the presence of emotion words in experimental tasks has an impact on the neural representation of emotional experiences and perceptions across studies. Using a database of 386 studies, we assessed brain activity when emotion words (e.g. ‘anger’, ‘disgust’) and more general affect words (e.g. ‘pleasant’, ‘unpleasant’) were present in experimental tasks vs not present. As predicted, when emotion words were present, we observed more frequent activations in regions related to semantic processing. When emotion words were not present, we observed more frequent activations in the amygdala and parahippocampal gyrus, bilaterally. The presence of affect words did not have the same effect on the neural representation of emotional experiences and perceptions, suggesting that our observed effects are specific to emotion words. These findings are consistent with the psychological constructionist prediction that in the absence of accessible emotion concepts, the meaning of affective experiences and perceptions are ambiguous. Findings are also consistent with the regulatory role of ‘affect labeling’. Implications of the role of language in emotion construction and regulation are discussed

Does Language Do More Than Communicate Emotion?

Language can certainly communicate emotions, but growing research suggests that language also helps constitute emotion by cohering sensations into specific perceptions of “anger,” “disgust,” “fear,” etc. The powerful role of language in emotion is predicted by a constructionist approach, which suggests that emotions occur when sensations are categorized using emotion category knowledge supported by language. We discuss the accumulating evidence from social cognitive, neuropsychological, cross-cultural, and neuroimaging studies that emotion words go beyond communication to help constitute emotional perceptions, and perhaps even emotional experiences. We look forward to current directions in research on emotional intelligence, emotion regulation, and psychotherapy

Adaptive Optics for Astronomy

Adaptive Optics is a prime example of how progress in observational astronomy can be driven by technological developments. At many observatories it is now considered to be part of a standard instrumentation suite, enabling ground-based telescopes to reach the diffraction limit and thus providing spatial resolution superior to that achievable from space with current or planned satellites. In this review we consider adaptive optics from the astrophysical perspective. We show that adaptive optics has led to important advances in our understanding of a multitude of astrophysical processes, and describe how the requirements from science applications are now driving the development of the next generation of novel adaptive optics techniques.Comment: to appear in ARA&A vol 50, 201