724,002 research outputs found

    Representing older people: towards meaningful images of the user in design scenarios

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    Designing for older people requires the consideration of a range of difficult and sometimes highly personal design problems. Issues such as fear, loneliness, dependency, and physical decline may be difficult to observe or discuss in interviews. Pastiche scenarios and pastiche personae are techniques that employ characters to create a space for the discussion of new technological developments and as a means to explore user experience. This paper argues that the use of such characters can help to overcome restrictive notions of older people by disrupting designers' prior assumptions. In this paper, we reflect on our experiences using pastiche techniques in two separate technology design projects that sought to address the needs of older people. In the first case pastiche scenarios were developed by the designers of the system and used as discussion documents with users. In the second case, pastiche personae were used by groups of users themselves to generate scenarios which were scribed for later use by the design team. We explore how the use of fictional characters and settings can generate new ideas and undermine rhetorical devices within scenarios that attempt to fit characters to the technology, rather than vice versa. To assist in future development of pastiche techniques in designing for older people, we provide an array of fictional older characters drawn from literary and popular culture.</p

    Signature Characters for A_2 and B_2

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    The signatures of the inner product matrices on a Lie algebra's highest weight representation are encoded in the representation's signature character. We show that the signature characters of a finite-dimensional Lie algebra's highest weight representations obey simple difference equations that have a unique solution once appropriate boundary conditions are imposed. We use these results to derive the signature characters of all A2A_2 and B2B_2 highest weight representations. Our results extend, and explain, signature patterns analogous to those observed by Friedan, Qiu and Shenker in the Virasoro algebra's representation theory.Comment: 22 p

    Unique Perfect Phylogeny Characterizations via Uniquely Representable Chordal Graphs

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    The perfect phylogeny problem is a classic problem in computational biology, where we seek an unrooted phylogeny that is compatible with a set of qualitative characters. Such a tree exists precisely when an intersection graph associated with the character set, called the partition intersection graph, can be triangulated using a restricted set of fill edges. Semple and Steel used the partition intersection graph to characterize when a character set has a unique perfect phylogeny. Bordewich, Huber, and Semple showed how to use the partition intersection graph to find a maximum compatible set of characters. In this paper, we build on these results, characterizing when a unique perfect phylogeny exists for a subset of partial characters. Our characterization is stated in terms of minimal triangulations of the partition intersection graph that are uniquely representable, also known as ur-chordal graphs. Our characterization is motivated by the structure of ur-chordal graphs, and the fact that the block structure of minimal triangulations is mirrored in the graph that has been triangulated

    Restriction of odd degree characters and natural correspondences

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    Let qq be an odd prime power, n>1n > 1, and let PP denote a maximal parabolic subgroup of GLn(q)GL_n(q) with Levi subgroup GLn1(q)×GL1(q)GL_{n-1}(q) \times GL_1(q). We restrict the odd-degree irreducible characters of GLn(q)GL_n(q) to PP to discover a natural correspondence of characters, both for GLn(q)GL_n(q) and SLn(q)SL_n(q). A similar result is established for certain finite groups with self-normalizing Sylow pp-subgroups. We also construct a canonical bijection between the odd-degree irreducible characters of SnS_n and those of MM, where MM is any maximal subgroup of SnS_n of odd index; as well as between the odd-degree irreducible characters of G=GLn(q)G = GL_n(q) or GUn(q)GU_n(q) with qq odd and those of NG(P)N_{G}(P), where PP is a Sylow 22-subgroup of GG. Since our bijections commute with the action of the absolute Galois group over the rationals, we conclude that the fields of values of character correspondents are the same. We use this to answer some questions of R. Gow
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