29,179 research outputs found
Emotive computing may have a role in telecare
This brief paper sets out arguments for the introduction of new technologies into telecare and lifestyle monitoring that can detect and monitor the emotive state of patients. The significantly increased use of computers by older people will enable the elements of emotive computing to be integrated with features such as keyboards and webcams, to provide additional information on emotional state. When this is combined with other data, there will be significant opportunities for system enhancement and the identification of changes in user status, and hence of need. The ubiquity of home computing makes the keyboard a very attractive, economic and non-intrusive means of data collection and analysis
Renormalizability of Effective Scalar Field Theory
We present a comprehensive discussion of the consistency of the effective
quantum field theory of a single symmetric scalar field. The theory is
constructed from a bare Euclidean action which at a scale much greater than the
particle's mass is constrained only by the most basic requirements; stability,
finiteness, analyticity, naturalness, and global symmetry. We prove to all
orders in perturbation theory the boundedness, convergence, and universality of
the theory at low energy scales, and thus that the theory is perturbatively
renormalizable in the sense that to a certain precision over a range of such
scales it depends only on a finite number of parameters. We then demonstrate
that the effective theory has a well defined unitary and causal analytic
S--matrix at all energy scales. We also show that redundant terms in the
Lagrangian may be systematically eliminated by field redefinitions without
changing the S--matrix, and discuss the extent to which effective field theory
and analytic S--matrix theory are actually equivalent. All this is achieved by
a systematic exploitation of Wilson's exact renormalization group flow
equation, as used by Polchinski in his original proof of the renormalizability
of conventional -theory.Comment: 80 pages, TeX, OUTP-93-23P, CERN-TH.7067/93. Many minor revisions,
and several new paragraph
Incompatible sets of gradients and metastability
We give a mathematical analysis of a concept of metastability induced by
incompatibility. The physical setting is a single parent phase, just about to
undergo transformation to a product phase of lower energy density. Under
certain conditions of incompatibility of the energy wells of this energy
density, we show that the parent phase is metastable in a strong sense, namely
it is a local minimizer of the free energy in an neighbourhood of its
deformation. The reason behind this result is that, due to the incompatibility
of the energy wells, a small nucleus of the product phase is necessarily
accompanied by a stressed transition layer whose energetic cost exceeds the
energy lowering capacity of the nucleus. We define and characterize
incompatible sets of matrices, in terms of which the transition layer estimate
at the heart of the proof of metastability is expressed. Finally we discuss
connections with experiment and place this concept of metastability in the
wider context of recent theoretical and experimental research on metastability
and hysteresis.Comment: Archive for Rational Mechanics and Analysis, to appea
Hybrid noiseless subsystems for quantum communication over optical fibers
We derive the general structure of noiseless subsystems for optical radiation
contained in a sequence of pulses undergoing collective depolarization in an
optical fiber. This result is used to identify optimal ways to implement
quantum communication over a collectively depolarizing channel, which in
general combine various degrees of freedom, such as polarization and phase,
into joint hybrid schemes for protecting quantum coherence.Comment: 5 pages, 1 figur
Linking recorded data with emotive and adaptive computing in an eHealth environment
Telecare, and particularly lifestyle monitoring, currently relies on the ability to detect and respond to changes in individual behaviour using data derived from sensors around the home. This means that a significant aspect of behaviour, that of an individuals emotional state, is not accounted for in reaching a conclusion as to the form of response required. The linked concepts of emotive and adaptive computing offer an opportunity to include information about emotional state and the paper considers how current developments in this area have the potential to be integrated within telecare and other areas of eHealth. In doing so, it looks at the development of and current state of the art of both emotive and adaptive computing, including its conceptual background, and places them into an overall eHealth context for application and development
Operator Relations for SU(3) Breaking Contributions to K and K* Distribution Amplitudes
We derive constraints on the asymmetry a1 of the momentum fractions carried
by quark and antiquark in K and K* mesons in leading twist. These constraints
follow from exact operator identities and relate a1 to SU(3) breaking
quark-antiquark-gluon matrix elements which we determine from QCD sum rules.
Comparing our results to determinations of a1 from QCD sum rules based on
correlation functions of quark currents, we find that, for a1^\parallel(K*) the
central values agree well and come with moderate errors, whereas for a1(K) and
a1^\perp(K*) the results from operator relations are consistent with those from
quark current sum rules, but come with larger uncertainties. The consistency of
results confirms that the QCD sum rule method is indeed suitable for the
calculation of a1. We conclude that the presently most accurate predictions for
a1 come from the direct determination from QCD sum rules based on correlation
functions of quark currents and are given by: a1(K) = 0.06\pm 0.03,
a1^\parallel(K*) = 0.03\pm 0.02, a1^\perp(K*) = 0.04\pm 0.03.Comment: 21 page
Expected Inflation and The Sacrifice Ratio
Using inflation forecasts from the OECD Economic Outlook as proxy measures of inflation expectations, we examine the impact of inflation expectations on the sacrifice ratio for 20 OECD countries. The regression analysis considers four different empirical models of the determinants of the sacrifice ratio typically found in the existing literature. The impact of the level of inflation expectations is negative and significant, implying that a higher level of expected inflation is associated with lower sacrifice ratios. This result is consistent with the theoretical role of nominal wage and price rigidities in that reductions in wage and price stickiness diminish the tradeoffs between disinflations and output losses. Interaction effects indicate that higher levels of expected inflation allow policymakers to pursue ‘cold turkey’ inflation reductions even more aggressively. The effect of the change in inflation expectations is negative and significant, implying that faster adjusting inflation expectations are associated with lower sacrifice ratios
Poisson transition rates from time-domain measurements with finite bandwidth
In time-domain measurements of a Poisson two-level system, the observed
transition rates are always smaller than those of the actual system, a general
consequence of finite measurement bandwidth in an experiment. This
underestimation of the rates is significant even when the measurement and
detection apparatus is ten times faster than the process under study. We derive
here a quantitative form for this correction using a straightforward
state-transition model that includes the detection apparatus, and provide a
method for determining a system's actual transition rates from
bandwidth-limited measurements. We support our results with computer
simulations and experimental data from time-domain measurements of
quasiparticle tunneling in a single-Cooper-pair transistor.Comment: 4 pages, 5 figure
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