26,800 research outputs found
Recommended from our members
A discourse approach to Korean politeness:towards a culture-specific Confucian framework
This thesis examines the inter-relationship between face, face work, and cultural values, as they apply to strategic politeness in Korean institutional settings, specifically university contexts. This study also seeks to explore issues of methodology for culture-specific politeness research, given that previous researchers either neglected cultural values, which operate sometimes outside of linguistic presentations, or used methods that prevented them from noticing the role of cultural values, which can function as another means of face redress in the construction of culture-specific politeness. The interactional aspects of language use demonstrate that the socio-pragmatics of cultural values/norms are essential elements in the construction of strategic politeness. However, previous researchers on politeness have never really looked into how culture-specific frameworks can function as both methodological and theoretical tools in the investigation of culture-specific politeness. Most politeness researchers have been mainly concerned with linguistic systems, and have paid less attention to cultural values that directly influence polite linguistic behavior. In this study, a Confucian framework was employed to explore both the linguistic forms and cultural values that are the core elements of Korean linguistic politeness. Korean politeness shows that a Confucian frame is needed as an interactional supplement to politeness research, because the cultural frame that Korean speakers use plays a decisive role in their choice of politeness forms. A Confucian framework allows analysis of how socio-cultural values interact with culture-specific cognitive dimensions. The intent in using a Confucian framework is to analyze how Confucian values can be realized through culture-specific discursive modes
Adjoint Trapping: A New Phenomenon at Strong 't Hooft Coupling
Adding matter of mass m, in the fundamental representation of SU(N), to N=4
supersymmetric Yang-Mills theory, we study ``generalized quarkonium''
containing a (s)quark, an anti(s)quark, and J massless (or very light) adjoint
particles. At large 't Hooft coupling >> 1, the states of spin <= 1
are surprisingly light (Kruczenski et al., hep-th/0304032) and small
(hep-th/0312071) with a J-independent size of order . This
``trapping'' of adjoint matter in a region small compared with its Compton
wavelength and compared to any confinement scale in the theory is an unfamiliar
phenomenon, as it does not occur at small . We explore adjoint
trapping further by considering the limit of large J. In particular, for J >>
>> 1, we expect the trapping phenomenon to become unstable.
Using Wilson loop methods, we show that a sharp transition, in which the
generalized quarkonium states become unbound (for massless adjoints) occurs at
. If the adjoint scalars of N=4 are massive and
the theory is confining (as, for instance, in N=1* theories) then the
transition becomes a cross-over, across which the size of the states changes
rapidly from ~ to something of order the confinement scale ~
.Comment: Clarified transition with a better figure and improved presentation;
added careful discussion of the small regime of validity of the
Born-Oppenheimer computation and adjusted some remarks appropriately; also
added two reference
Identifying Retweetable Tweets with a Personalized Global Classifier
In this paper we present a method to identify tweets that a user may find
interesting enough to retweet. The method is based on a global, but
personalized classifier, which is trained on data from several users,
represented in terms of user-specific features. Thus, the method is trained on
a sufficient volume of data, while also being able to make personalized
decisions, i.e., the same post received by two different users may lead to
different classification decisions. Experimenting with a collection of approx.\
130K tweets received by 122 journalists, we train a logistic regression
classifier, using a wide variety of features: the content of each tweet, its
novelty, its text similarity to tweets previously posted or retweeted by the
recipient or sender of the tweet, the network influence of the author and
sender, and their past interactions. Our system obtains F1 approx. 0.9 using
only 10 features and 5K training instances.Comment: This is a long paper version of the extended abstract titled "A
Personalized Global Filter To Predict Retweets", of the same authors, which
was published in the 25th ACM UMAP conference in Bratislava, Slovakia, in
July 201
Interaction Effects in the Mesoscopic Regime: A Quantum Monte Carlo Study of Irregular Quantum Dots
We address the issue of accurately treating interaction effects in the
mesoscopic regime by investigating the ground state properties of isolated
irregular quantum dots. Quantum Monte Carlo techniques are used to calculate
the distributions of ground state spin and addition energy. We find a reduced
probability of high spin and a somewhat larger even/odd alternation in the
addition energy from quantum Monte Carlo than in local spin density functional
theory. In both approaches, the even/odd effect gets smaller with increasing
number of electrons, contrary to the theoretical understanding of large dots.
We argue that the local spin density approximation over predicts the effects of
interactions in quantum dots.Comment: Final Version, to appear in PRB as a Rapid Com
Phase cascade lattice rectifier array: an exactly solvable nonlinear network circuit
An exact analysis of a 2-D lattice network consisting of N Ă N sites with rectifier and AC source elements with controllable phases reveals a method for generating ripple-free DC power without the use of any filtering circuit elements. A phase cascade configuration is described in which the current ripple in a load resistor goes to zero in the large N limit, enhancing the rectification efficiency without requiring any additional capacitor or inductor based filters. The integrated modular configuration is qualitatively different from conventional rectenna arrays in which the source, rectifier and filter systems are physically disjoint. Nonlinear networks in the large N limit of source-rectifier arrays are potentially of interest to a fast evolving field of distributed power networks.MNacknowledges support from a Graduate Fellowship in the ECE department at Boston University. We thank CMaedler, R Averitt, and members of the Photonics Center staff for assistance. JC acknowledges support from the Boston University RISE summer program. (Graduate Fellowship in the ECE department at Boston University; Boston University RISE summer program)Published versio
Effect of pressure on the quantum spin ladder material IPA-CuCl3
Inelastic neutron scattering and bulk magnetic susceptibility studies of the
quantum S=1/2 spin ladder system IPA-CuCl3 are performed under hydrostatic
pressure. The pressure dependence of the spin gap is determined. At
GPa it is reduced to meV from meV at
ambient pressure. The results allow us to predict a soft-mode quantum phase
transition in this system at P GPa. The measurements are
complicated by a proximity of a structural phase transition that leads to a
deterioration of the sample.Comment: 5 pages, 4 figure
Entanglement production and decoherence-free subspace of two single-mode cavities embedded in a common environment
A system consisting of two identical single-mode cavities coupled to a common
environment is investigated within the framework of algebraic dynamics. Based
on the left and right representations of the Heisenberg-Weyl algebra, the
algebraic structure of the master equation is explored and exact analytical
solutions of this system are obtained. It is shown that for such a system, the
environment can produce entanglement in contrast to its commonly believed role
of destroying entanglement. In addition, the collective zero-mode eigen
solutions of the system are found to be free of decoherence against the
dissipation of the environment. These decoherence-free states may be useful in
quantum information and quantum computation.Comment: 10 pages, 7 figures, Revtex
Testing Spatial Noncommutativity via Magnetic Hyperfine Structure Induced by Fractional Angular Momentum of Rydberg System
An approach to solve the critical problem of testing quantum effects of
spatial noncommutativity is proposed. Magnetic hyperfine structures in a
Rydberg system induced by fractional angular momentum originated from spatial
noncommutativity are discussed. The orders of the corresponding magnetic
hyperfine splitting of spectrum lie within the
limits of accuracy of current experimental measurements. Experimental tests of
physics beyond the standard model are the focus of broad interest. We note that
the present approach is reasonable achievable with current technology. The
proof is based on very general arguments involving only the deformed
Heisenberg-Weyl algebra and the fundamental property of angular momentum. Its
experimental verification would constitute an advance in understanding of
fundamental significance, and would be a key step towards a decisive test of
spatial noncommutativity.Comment: 11 pages, no figure
Multivariate Variance Ratio Statistics
We propose several multivariate variance ratio statistics. We derive the asymptotic distribution of the statistics and scalar functions thereof under the null hypothesis that returns are unpredictable after a constant mean adjustment (i.e., under the Efficient Market Hypothesis). We do not impose the no leverage assumption of Lo and MacKinlay (1988) but our asymptotic standard errors are relatively simple and in particular do not require the selection of a bandwidth parameter. We extend the framework to allow for a smoothly varying risk premium in calendar time, and show that the limiting distribution is the same as in the constant mean adjustment case. We show the limiting behaviour of the statistic under a multivariate fads model and under a moderately explosive bubble process: these alternative hypotheses give opposite predictions with regards to the long run value of the statistics. We apply the methodology to three weekly size-sorted CRSP portfolio returns from 1962 to 2013 in three subperiods. We find evidence of a reduction of linear predictability in the most recent period, for small and medium cap stocks. We find similar results for the main UK stock indexes. The main findings are not substantially affected by allowing for a slowly varying risk premium
An investigation into Multivariate Variance Ratio Statistics and their application to Stock Market Predictability
We propose several multivariate variance ratio statistics. We derive the asymptotic distribution of the statistics and scalar functions thereof under the null hypothesis that returns are unpredictable after a constant mean adjustment (i.e., under the weak form Efficient Market Hypothesis). We do not impose the no leverage assumption of Lo and MacKinlay (1988) but our asymptotic standard errors are relatively simple and in particular do not require the selection of a bandwidth parameter. We extend the framework to allow for a time varying risk premium through common systematic factors. We show the limiting behaviour of the statistic under a multivariate fads model and under a moderately explosive bubble process: these alternative hypotheses give opposite predictions with regards to the long run value of the statistics. We apply the methodology to five weekly size-sorted CRSP portfolio returns from 1962 to 2013 in three subperiods. period, for small and medium cap stocks. The main findings are not substantially affected by allowing for a common factor time varying risk premium
- âŠ