73,497 research outputs found

    Studying and Modeling the Connection between People's Preferences and Content Sharing

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    People regularly share items using online social media. However, people's decisions around sharing---who shares what to whom and why---are not well understood. We present a user study involving 87 pairs of Facebook users to understand how people make their sharing decisions. We find that even when sharing to a specific individual, people's own preference for an item (individuation) dominates over the recipient's preferences (altruism). People's open-ended responses about how they share, however, indicate that they do try to personalize shares based on the recipient. To explain these contrasting results, we propose a novel process model of sharing that takes into account people's preferences and the salience of an item. We also present encouraging results for a sharing prediction model that incorporates both the senders' and the recipients' preferences. These results suggest improvements to both algorithms that support sharing in social media and to information diffusion models.Comment: CSCW 201

    Reply on `comment on our paper `Single two-level ion in an anharmonic-oscillator trap: Time evolution of the Q function and population inversion ''

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    We show here that the model Hamiltonian used in our paper for ion vibrating in a q-analog harmonic oscillator trap and interacting with a classical single-mode light field is indeed obtained by replacing the usual bosonic creation and annihilation operators of the harmonic trap model by their q-deformed counterparts. The approximations made in our paper amount to using for the ion-laser interaction in a q-analog harmonic oscillator trap, the operator F_{q}=exp{-(|\epsilon|^2}/2)}exp{i\epsilon A^{\dagger}}exp{i\epsilon A}, which is analogous to the corresponding operator for ion in a harmonic oscillator trap that is F=exp−(∣ϵ∣2/2)expiϵa†expiϵaF=exp{-(|\epsilon|^2 /2)}exp{i\epsilon a^{\dagger }}exp{i\epsilon a}. In our article we do not claim to have diagonalized the operator, Fq=expiϵ(A†+A)F_q = exp{i \epsilon (A^{\dagger}+A)}, for which the basis states |g,m> and |e,m> are not analytic vectors.Comment: Revtex, 4pages. To be Published in Physical Review A59, NO.4(April 99

    Methods for the Study of Transverse Momentum Differential Correlations

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    We introduce and compare three differential correlation functions for the study of transverse momentum correlation in p+pp+p and A+AA+A collisions. These consist of {\it inclusive}, {\it event-wise} and a differential version of the correlation measure C~\tilde C introduced by Gavin \cite{Gavin} for experimental study of the viscosity per unit entropy of the matter produced in A+AA+A collisions. We study the quantitative difference between the three observables on the basis of PYTHIA simulations of p+pp+p collisions and A+AA+A collisions consisting of an arbitrary superposition of p+pp+p collision events at s=\sqrt{s} = 200 GeV. We observe that {\it inclusive} and {\it event-wise} correlation functions are remarkably identical to each other where as the observable C~\tilde C differs from the two. We study the robustness and efficiency dependencies of these observables based on truncated Taylor expansions in efficiency in p+pp+p collisions and on the basis of Monte Carlo simulation using an adhoc detector efficiency parameterization. We find that all the three observables are essentially independent of detector efficiency. We additionally study the scaling of the correlation measures and find all the observables exhibit an approximate 1/N1/N dependence of the number of participants ({\it N}) in A+AA+A collisions. Finally, we study the impact of flow-like anisotropy on the {\it inclusive} correlation function and find flow imparts azimuthal modulations similar to those observed with two-particle densities.Comment: 19 pages, 8 figure
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