1,729 research outputs found
Yang-Mills Connections on Nonorientable Surfaces
In "The Yang-Mills equations over Riemann surfaces", Atiyah and Bott studied
Yang-Mills functional over a Riemann surface from the point of view of Morse
theory. We generalize their study to all closed, compact, connected, possibly
nonorientable surfaces. We introduce the notion of "super central extension" of
the fundamental group of a surface. It is the central extension when the
surface is orientable. We establish a precise correspondence between Yang-Mills
connections and representations of super central extension. Knowing this exact
correspondence, we work mainly at the level of representation varieties which
are finite dimensional instead of the level of strata which are infinite
dimensional.Comment: 45 pages, 1 figur
Asynchronous Remote Medical Consultation for Ghana
Computer-mediated communication systems can be used to bridge the gap between
doctors in underserved regions with local shortages of medical expertise and
medical specialists worldwide. To this end, we describe the design of a
prototype remote consultation system intended to provide the social,
institutional and infrastructural context for sustained, self-organizing growth
of a globally-distributed Ghanaian medical community. The design is grounded in
an iterative design process that included two rounds of extended design
fieldwork throughout Ghana and draws on three key design principles (social
networks as a framework on which to build incentives within a self-organizing
network; optional and incremental integration with existing referral
mechanisms; and a weakly-connected, distributed architecture that allows for a
highly interactive, responsive system despite failures in connectivity). We
discuss initial experiences from an ongoing trial deployment in southern Ghana.Comment: 10 page
Human computer interaction for international development: past present and future
Recent years have seen a burgeoning interest in research into the use of information and communication technologies (ICTs) in the context of developing regions, particularly into how such ICTs might be appropriately designed to meet the unique user and infrastructural requirements that we encounter in these cross-cultural environments. This emerging field, known to some as HCI4D, is the product of a diverse set of origins. As such, it can often be difficult to navigate prior work, and/or to piece together a broad picture of what the field looks like as a whole. In this paper, we aim to contextualize HCI4D—to give it some historical background, to review its existing literature spanning a number of research traditions, to discuss some of its key issues arising from the work done so far, and to suggest some major research objectives for the future
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