3,492 research outputs found
On the domain wall partition functions of level-1 affine so(n) vertex models
We derive determinant expressions for domain wall partition functions of
level-1 affine so(n) vertex models, n >= 4, at discrete values of the crossing
parameter lambda = m pi / 2(n-3), m in Z, in the critical regime.Comment: 14 pages, 13 figures included in latex fil
Latent Space Model for Multi-Modal Social Data
With the emergence of social networking services, researchers enjoy the
increasing availability of large-scale heterogenous datasets capturing online
user interactions and behaviors. Traditional analysis of techno-social systems
data has focused mainly on describing either the dynamics of social
interactions, or the attributes and behaviors of the users. However,
overwhelming empirical evidence suggests that the two dimensions affect one
another, and therefore they should be jointly modeled and analyzed in a
multi-modal framework. The benefits of such an approach include the ability to
build better predictive models, leveraging social network information as well
as user behavioral signals. To this purpose, here we propose the Constrained
Latent Space Model (CLSM), a generalized framework that combines Mixed
Membership Stochastic Blockmodels (MMSB) and Latent Dirichlet Allocation (LDA)
incorporating a constraint that forces the latent space to concurrently
describe the multiple data modalities. We derive an efficient inference
algorithm based on Variational Expectation Maximization that has a
computational cost linear in the size of the network, thus making it feasible
to analyze massive social datasets. We validate the proposed framework on two
problems: prediction of social interactions from user attributes and behaviors,
and behavior prediction exploiting network information. We perform experiments
with a variety of multi-modal social systems, spanning location-based social
networks (Gowalla), social media services (Instagram, Orkut), e-commerce and
review sites (Amazon, Ciao), and finally citation networks (Cora). The results
indicate significant improvement in prediction accuracy over state of the art
methods, and demonstrate the flexibility of the proposed approach for
addressing a variety of different learning problems commonly occurring with
multi-modal social data.Comment: 12 pages, 7 figures, 2 table
Cascades: A view from Audience
Cascades on online networks have been a popular subject of study in the past
decade, and there is a considerable literature on phenomena such as diffusion
mechanisms, virality, cascade prediction, and peer network effects. However, a
basic question has received comparatively little attention: how desirable are
cascades on a social media platform from the point of view of users? While
versions of this question have been considered from the perspective of the
producers of cascades, any answer to this question must also take into account
the effect of cascades on their audience. In this work, we seek to fill this
gap by providing a consumer perspective of cascade.
Users on online networks play the dual role of producers and consumers.
First, we perform an empirical study of the interaction of Twitter users with
retweet cascades. We measure how often users observe retweets in their home
timeline, and observe a phenomenon that we term the "Impressions Paradox": the
share of impressions for cascades of size k decays much slower than frequency
of cascades of size k. Thus, the audience for cascades can be quite large even
for rare large cascades. We also measure audience engagement with retweet
cascades in comparison to non-retweeted content. Our results show that cascades
often rival or exceed organic content in engagement received per impression.
This result is perhaps surprising in that consumers didn't opt in to see tweets
from these authors. Furthermore, although cascading content is widely popular,
one would expect it to eventually reach parts of the audience that may not be
interested in the content. Motivated by our findings, we posit a theoretical
model that focuses on the effect of cascades on the audience. Our results on
this model highlight the balance between retweeting as a high-quality content
selection mechanism and the role of network users in filtering irrelevant
content
Game saturation of intersecting families
We consider the following combinatorial game: two players, Fast and Slow,
claim -element subsets of alternately, one at each turn,
such that both players are allowed to pick sets that intersect all previously
claimed subsets. The game ends when there does not exist any unclaimed
-subset that meets all already claimed sets. The score of the game is the
number of sets claimed by the two players, the aim of Fast is to keep the score
as low as possible, while the aim of Slow is to postpone the game's end as long
as possible. The game saturation number is the score of the game when both
players play according to an optimal strategy. To be precise we have to
distinguish two cases depending on which player takes the first move. Let
and denote the score of
the saturation game when both players play according to an optimal strategy and
the game starts with Fast's or Slow's move, respectively. We prove that
holds
Theory of High-Tc Superconductivity: Accurate Predictions of Tc
The superconducting transition temperatures of high-Tc compounds based on
copper, iron, ruthenium and certain organic molecules are discovered to be
dependent on bond lengths, ionic valences, and Coulomb coupling between
electronic bands in adjacent, spatially separated layers [1]. Optimal
transition temperature, denoted as T_c0, is given by the universal expression
; is the spacing between interacting
charges within the layers, \zeta is the distance between interacting layers and
\Lambda is a universal constant, equal to about twice the reduced electron
Compton wavelength (suggesting that Compton scattering plays a role in
pairing). Non-optimum compounds in which sample degradation is evident
typically exhibit Tc < T_c0. For the 31+ optimum compounds tested, the
theoretical and experimental T_c0 agree statistically to within +/- 1.4 K. The
elemental high Tc building block comprises two adjacent and spatially separated
charge layers; the factor e^2/\zeta arises from Coulomb forces between them.
The theoretical charge structure representing a room-temperature superconductor
is also presented.Comment: 7 pages 5 references, 6 figures 1 tabl
The Causal Structure of Emotions in Aristotle: Hylomorphism, Causal Interaction between Mind and Body, and Intentionality
Recently, a strong hylomorphic reading of Aristotelian emotions has been put forward, one that allegedly eliminates the problem of causal interaction between soul and body. Taking the presentation of emotions in de An. I 1 as a starting point and basic thread, but relying also on the discussion of Rh. II, I will argue that this reading only takes into account two of the four causes of emotions, and that, if all four of them
are included into the picture, then a causal interaction of mind and body remains within Aristotelian emotions, independent of how strongly their hylomorphism is understood. Beyond the discussion with this recent reading, the analysis proposed of the fourfold causal structure of emotions is also intended as a hermeneutical starting point for a comprehensive analysis of particular emotions in Aristotle. Through the different causes Aristotle seems to account for many aspects of the complex phenomenon of emotion, including its physiological causes, its mental causes, and its intentional object
Risky Driving by Recently Licensed Teens: Self-Reports and Simulated Performance
U.S. teens are overrepresented in motor vehicle crashes, with the majority due to driver error; however, causal pathways remain to be elucidated. This research aimed to identify driving performance factors that might underlie newly-licensed male teens’ risk. Surveys were conducted with 21 16-year-olds at the time of intermediate licensure. During the second month of licensure they completed drives in a high-fidelity simulator. Simulator scenarios allowed assessment of responses to yellow traffic lights changing to red and to a visual search task, for which previous data on older age groups of drivers were available. All teens had an A or B grade point average, previously found to be associated with lower crash and citation risk. Nonetheless, 71% reported risky driving in terms of prior unlicensed, unsupervised driving. In the simulator, 46% went through an intersection as the light turned red, compared to 33% of adults. In the visual search task, teens had shorter mean perception-reaction times and identified more targets than adults and older drivers, but similar to young drivers. Therefore, even teens with good grades, perceived to be less risky, were willing to take driving risks. Their driving performance suggests there may be subtle differences in the way recently-licensed teens drive that might predispose them to crashes. Further research of this nature can increase understanding of such differences and inform the development of more targeted intervention
Exact solutions and stability of rotating dipolar Bose-Einstein condensates in the Thomas-Fermi limit
We present a theoretical analysis of dilute gas Bose-Einstein condensates
with dipolar atomic interactions under rotation in elliptical traps. Working in
the Thomas-Fermi limit, we employ the classical hydrodynamic equations to first
derive the rotating condensate solutions and then consider their response to
perturbations. We thereby map out the regimes of stability and instability for
rotating dipolar Bose-Einstein condensates and in the latter case, discuss the
possibility of vortex lattice formation. We employ our results to propose
several novel routes to induce vortex lattice formation in a dipolar
condensate.Comment: 12 pages with 6 figure
Critical Velocity of Vortex Nucleation in Rotating Superfluid 3He-A
We have measured the critical velocity v_c at which 3He-A in a rotating
cylinder becomes unstable against the formation of quantized vortex lines with
continuous (singularity-free) core structure. We find that v_c is distributed
between a maximum and minimum limit, which we ascribe to a dependence on the
texture of the orbital angular momentum l(r) in the cylinder. Slow cool down
through T_c in rotation yields l(r) textures for which the measured v_c's are
in good agreement with the calculated instability of the expected l texture.Comment: 4 pages, 3 figure
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