1,205 research outputs found
On a nonstandard two-parametric quantum algebra and its connections with and
A quantum algebra associated with a nonstandard
-matrix with two deformation parameters is studied and, in
particular, its universal -matrix is derived using Reshetikhin's
method. Explicit construction of the -dependent nonstandard -matrix
is obtained through a coloured generalized boson realization of the universal
-matrix of the standard corresponding to a
nongeneric case. General finite dimensional coloured representation of the
universal -matrix of is also derived. This
representation, in nongeneric cases, becomes a source for various
-dependent nonstandard -matrices. Superization of leads to the super-Hopf algebra . A contraction
procedure then yields a -deformed super-Heisenberg algebra
and its universal -matrix.Comment: 17pages, LaTeX, Preprint No. imsc-94/43 Revised version: A note added
at the end of the paper correcting and clarifying the bibliograph
Familiarization: A theory of repetition suppression predicts interference between overlapping cortical representations
Repetition suppression refers to a reduction in the cortical response to a novel stimulus that
results from repeated presentation of the stimulus. We demonstrate repetition suppression
in a well established computational model of cortical plasticity, according to which the relative
strengths of lateral inhibitory interactions are modified by Hebbian learning. We present
the model as an extension to the traditional account of repetition suppression offered by
sharpening theory, which emphasises the contribution of afferent plasticity, by instead
attributing the effect primarily to plasticity of intra-cortical circuitry. In support, repetition suppression
is shown to emerge in simulations with plasticity enabled only in intra-cortical connections.
We show in simulation how an extended ‘inhibitory sharpening theory’ can explain
the disruption of repetition suppression reported in studies that include an intermediate
phase of exposure to additional novel stimuli composed of features similar to those of the
original stimulus. The model suggests a re-interpretation of repetition suppression as a manifestation
of the process by which an initially distributed representation of a novel object
becomes a more localist representation. Thus, inhibitory sharpening may constitute a more
general process by which representation emerges from cortical re-organisation
Loitering with intent: dealing with human-intensive systems
This paper discusses the professional roles of information systems analysts and users, focusing on a perspective of human intensive, rather than software intensive information systems. The concept of ‘meaningful use’ is discussed in re-lation to measures of success/failure in IS development. The authors consider how a number of different aspects of reductionism may distort analyses, so that processes of inquiry cannot support organizational actors to explore and shape their requirements in relation to meaningful use. Approaches which attempt to simplify complex problem spaces, to render them more susceptible to ‘solution’ are problematized. Alternative perspectives which attempt a systematic, holistic complexification, by supporting contextual dependencies to emerge, are advocated as a way forward
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