1,370 research outputs found

    Introducing New Methodologies for Identifying Design Patterns for Internationalization and Localization

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    This paper describes a new methodology for deriving interaction design patterns from an analysis of ethnographic data. It suggests using inductive and deductive analysis processes to identify and articulate patterns that address the needs of culturally diverse users of interactive, collaborative systems. This might inform the internationalization and localization process of computer supported collaboration systems

    How far does the analogy between causal horizon-induced thermalization with the standard heat bath situation go?

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    After a short presentation of KMS states and modular theory as the unifying description of thermalizing systems we propose the absence of transverse vacuum fluctuations in the holographic projections as the mechanism for an area behavior (the transverse area) of localization entropy as opposed to the volume dependence of ordinary heat bath entropy. Thermalization through causal localization is not a property of QM, but results from the omnipresent vacuum polarization in QFT and does not require a Gibbs type ensemble avaraging (coupling to a heat bath).Comment: 10 pages, based on talk given at the 2002 Londrina Winter Schoo

    Wedge Local Deformations of Charged Fields leading to Anyonic Commutation Relations

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    The method of deforming free fields by using multiplication operators on Fock space, introduced by G. Lechner in [11], is generalized to a charged free field on two- and three-dimensional Minkowski space. In this case the deformation function can be chosen in such a way that the deformed fields satisfy generalized commutation relations, i.e. they behave like Anyons instead of Bosons. The fields are "polarization free" in the sense that they create only one-particle states from the vacuum and they are localized in wedges (or "paths of wedges"), which makes it possible to circumvent a No-Go theorem by J. Mund [12], stating that there are no free Anyons localized in spacelike cones. The two-particle scattering matrix, however, can be defined and is different from unity

    Deformations of quantum field theories on de Sitter spacetime

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    Quantum field theories on de Sitter spacetime with global U(1) gauge symmetry are deformed using the joint action of the internal symmetry group and a one-parameter group of boosts. The resulting theory turns out to be wedge-local and non-isomorphic to the initial one for a class of theories, including the free charged Dirac field. The properties of deformed models coming from inclusions of CAR-algebras are studied in detail.Comment: 26 pages, no figure

    Local Nature of Coset Models

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    The local algebras of the maximal Coset model C_max associated with a chiral conformal subtheory A\subset B are shown to coincide with the local relative commutants of A in B, provided A contains a stress energy tensor. Making the same assumption, the adjoint action of the unique inner-implementing representation U^A associated with A\subset B on the local observables in B is found to define net-endomorphisms of B. This property is exploited for constructing from B a conformally covariant holographic image in 1+1 dimensions which proves useful as a geometric picture for the joint inclusion A\vee C_max \subset B. Immediate applications to the analysis of current subalgebras are given and the relation to normal canonical tensor product subfactors is clarified. A natural converse of Borchers' theorem on half-sided translations is made accessible.Comment: 33 pages, no figures; typos, minor improvement

    Abundance and distribution of narwhals (Monodon monoceros) on the summering grounds in Greenland between 2007-2019

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    Narwhal abundance in West Greenland (WG) and East Greenland (EG) was estimated from aerial surveys conducted between 2007 and 2019 at their summer grounds. Analyses were completed using Mark Recapture Distance Sampling and Hidden Markov Line Transect Models taking account of the stochastic availability of diving whales. No statistically significant difference in abundance of narwhals could be detected for the two summer grounds (Melville Bay and Inglefield Bredning) in WG between 2007 and 2019. The distribution of narwhals in Inglefield Bredning was similar between years but in Melville Bay, area usage has decreased >80% since the first survey in 2007. Few detections of narwhals were obtained during the surveys in EG and a common detection function was fitted from combining sightings from seven surveys. Narwhals were found in small aggregations distributed between Nordostrundingen and south to and including Tasiilaq. Abundance of narwhals was estimated for the first time in the relatively unexplored Northeast Greenland (Dove Bay and a restricted coastal area of the Greenland Sea). The abundance in these two areas was 2908 narwhals (CV=0.30; 95% CI:1639-5168) estimated in 2017 for the Greenland Sea and 2297 (0.38; 1123-4745) and 1395 (0.33; 744-2641) narwhals were estimated for Dove Bay in 2017 and 2018, respectively. Both abundance and distribution range of narwhals in Southeast Greenland, where narwhals are subject to subsistence harvest, has decreased significantly between 2008-2017 and narwhals have even disappeared at the southernmost area since the first surveys in 2008.Peer reviewe

    Policies and scenarios for Cape Town's energy future: options for sustainable city energy development

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    This study examines a set of energy policy interventions, which can make a major contribution to sustainable development for the City of Cape Town – economically, environmentally and socially. Major energy savings can be made from modal shifts in the transport sector, and with efficient lighting. The savings make a contribution to economic development, by freeing up resources. The savings from energy efficiency also have important social benefits in energy savings, reducing energy bills for poor households. From an environmental point of view, implementing the city’s renewable energy target will have significant costs, but these can be partly off-set by selling carbon credits through the Clean Development Mechanism, and will result in indirect health benefits. Targeted interventions can reduce local air pollution, and help Cape Town become a leader in addressing greenhouse gas emissions. Apart from examining the social, economic and environmental dimensions of each policy, this paper compares policies to one another. Of particular interest for sustainable energy development are those policies which are viable in terms of costs, social benefits and the environment. Compact Fluorescent Lamps (CFLs) in residential, commercial and government sectors and heating ventilation and air conditioning (HVAC) in commerce and government sectors stand out as policies that have benefits from every angle. The paper builds on previous work done on the ‘state of energy’ for Cape Town and develops a tool that can paint a picture of what might happen to energy in the future. Using the Long-Range Energy Alternatives Planning (LEAP) modelling tool, a set of energy policies have been simulated

    Warped Convolutions, Rieffel Deformations and the Construction of Quantum Field Theories

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    Warped convolutions of operators were recently introduced in the algebraic framework of quantum physics as a new constructive tool. It is shown here that these convolutions provide isometric representations of Rieffel's strict deformations of C*-dynamical systems with automorphic actions of R^n, whenever the latter are presented in a covariant representation. Moreover, the device can be used for the deformation of relativistic quantum field theories by adjusting the convolutions to the geometry of Minkowski space. The resulting deformed theories still comply with pertinent physical principles and their Tomita-Takesaki modular data coincide with those of the undeformed theory; but they are in general inequivalent to the undeformed theory and exhibit different physical interpretations.Comment: 34 page
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