522 research outputs found

    UK Fashion Designers Working in Micro-sized Enterprises; Attitudes to Locational Resources, Their Peers and the Market

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    This paper contributes to an understanding of the importance of locally based resources and interactions in a globalised industry, fashion design. It examines the product design stage of the fashion production chain, rather than the manufacture and commercialisation of apparel products. We studied the use of their geographies by UK-based fashion designers working in micro-sized enterprises ( < 10 employees) especially because of their likely sensitivity to various aspects of proximity, including their dependence on external resources to supplement their own. Factor and cluster analysis identified four different types of designers, which differed in the manner in which they interacted with peers and markets, and accessed location-based resources. The paper advances explanations for the patterns of behaviour observed in the various clusters, and in making recommendations for further research predicts the types of design position each is likely to prefer

    Effects of 9-hour time zone changes on fatigue and circadian rhythms of sleep/wake and core temperature

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    Physiological and psychological disruptions caused by transmeridian flights may affect the ability of flight crews to meet operational demands. To study these effects, 9 Royal Norwegian Airforces P3-Orion crewmembers flew from Norway to California (-9 hr), and back (+9 hr). Rectal temperature, heart rate and wrist activity were recorded every 2 min, fatigue and mood were rated every 2 hr during the waking day, and logs were kept of sleep times and ratings. Subjects also completed 4 personality inventories. The time-zone shifts produced negative changes in mood which persisted longer after westward flights. Sleep quality (subjective and objective) and duration were slightly disrupted (more after eastward flights). The circadian rhythms of sleep/wake and temperature both completed the 9-hr delay by day 5 in California, although temperature adjusted more slowly. The size of the delay shift was significantly correlated with scores on extraversion and achievement need personality scales. Response to the 9-hr advance were more variable. One subject exhibited a 15-hr delay in his temperature rhythm, and an atypical sleep/nap pattern. On average, the sleep/wake cycle (but not the temperature rhythm), completed the 9-hr advance by the end of the study. Both rhythms adapted more slowly after the eastward flight

    Linear and nonlinear substructured Restricted Additive Schwarz iterations and preconditioning

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    Iterative substructuring Domain Decomposition (DD) methods have been extensively studied, and they are usually associated with nonoverlapping decompositions. It is less known that classical overlapping DD methods can also be formulated in substructured form, i.e., as iterative methods acting on variables defined exclusively on the interfaces of the overlapping domain decomposition. We call such formulations substructured domain decomposition methods. We introduce here a substructured version of Restricted Additive Schwarz (RAS) which we call SRAS. We show that RAS and SRAS are equivalent when used as iterative solvers, as they produce the same iterates, while they are substantially different when used as preconditioners for GMRES. We link the volume and substructured Krylov spaces and show that the iterates are different by deriving the least squares problems solved at each GMRES iteration. When used as iterative solvers, SRAS presents computational advantages over RAS, as it avoids computations with matrices and vectors at the volume level. When used as preconditioners, SRAS has the further advantage of allowing GMRES to store smaller vectors and perform orthogonalization in a lower dimensional space. We then consider nonlinear problems, and we introduce SRASPEN (Substructured Restricted Additive Schwarz Preconditioned Exact Newton), where SRAS is used as a preconditioner for Newton’s method. In contrast to the linear case, we prove that Newton’s method applied to the preconditioned volume and substructured formulation produces the same iterates in the nonlinear case. Next, we introduce two-level versions of nonlinear SRAS and SRASPEN. Finally, we validate our theoretical results with numerical experiments

    Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

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    A rotatable-jaw collimator design was conceived as a solution to recover from catastrophic beam impacts which would damage a collimator at the Large Hadron Collider (LHC) or its High-Luminosity upgrade (HL-LHC). One such rotatable collimator prototype was designed and built at SLAC and delivered to CERN for tests with LHC-type circulating beams in the Super Proton Synchrotron (SPS). This was followed by destructive tests at the dedicated High Radiation to Materials (HiRadMat) facility to validate the design and rotation functionality. An overview of the collimator design, together with results from tests without and with beam are presented

    "You have to get wet to learn how to swim" applied to bridging the gap between research into personnel scheduling and its implementation in practice

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    Personnel scheduling problems have attracted research interests for several decades. They have been considerably changed over time, accommodating a variety of constraints related to legal and organisation requirements, part-time staff, flexible hours of staff, staff preferences, etc. This led to a myriad of approaches developed for solving personnel scheduling problems including optimisation, meta-heuristics, artificial intelligence, decision-support, and also hybrids of these approaches. However, this still does not imply that this research has a large impact on practice and that state-of-the art models and algorithms are widely in use in organisations. One can find a reasonably large number of software packages that aim to assist in personnel scheduling. A classification of this software based on its purpose will be proposed, accompanied with a discussion about the level of support that this software offers to schedulers. A general conclusion is that the available software, with some exceptions, does not benefit from the wealth of developed models and methods. The remaining of the paper will provide insights into some characteristics of real-world scheduling problems that, in the author’s opinion, have not been given a due attention in the personnel scheduling research community yet and which could contribute to the enhancement of the implementation of research results in practice. Concluding remarks are that in order to bridge the gap that still exists between research into personnel scheduling and practice, we need to engage more with schedulers in practice and also with software developers; one may say we need to get wet if we want to learn how to swim

    'Let's make lots of money': the determinants of performance in the recorded music sector

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    This research analyzes the performance of 467 record labels in eight European countries over a period of 13 years (2003-2015). The main goal is to explain a relative measure of profitability in terms of observed variables, although the nature of the dataset also allows us to include non-observed firm and country effects. To this end alternative models are estimated and three main research questions are tested, namely: (1) the effect of the dual structure of the recorded music market, in which a competitive segment and an oligopoly coexist; (2) the extent and source of the volatility of profits in record labels; and (3) the nonlinear impact of size on performance

    Modeling and discretization of flow in porous media with thin, full-tensor permeability inclusions

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    When modeling fluid flow in fractured reservoirs, it is common to represent the fractures as lower-dimensional inclusions embedded in the host medium. Existing discretizations of flow in porous media with thin inclusions assume that the principal directions of the inclusion permeability tensor are aligned with the inclusion orientation. While this modeling assumption works well with tensile fractures, it may fail in the context of faults, where the damage zone surrounding the main slip surface may introduce anisotropy that is not aligned with the main fault orientation. In this article, we introduce a generalized dimensional reduced model which preserves full-tensor permeability effects also in the out-of-plane direction of the inclusion. The governing equations of flow for the lower-dimensional objects are obtained through vertical averaging. We present a framework for discretization of the resulting mixed-dimensional problem, aimed at easy adaptation of existing simulation tools. We give numerical examples that show the failure of existing formulations when applied to anisotropic faulted porous media, and go on to show the convergence of our method in both two-dimensional and three-dimensional.publishedVersio
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