87 research outputs found
Modeling competitive evolution of multiple languages
Increasing evidence demonstrates that in many places language coexistence has
become ubiquitous and essential for supporting language and cultural diversity
and associated with its financial and economic benefits. The competitive
evolution among multiple languages determines the evolution outcome, either
coexistence, decline, or extinction. Here, we extend the Abrams-Strogatz model
of language competition to multiple languages and then validate it by analyzing
the behavioral transitions of language usage over the recent several decades in
Singapore and Hong Kong. In each case, we estimate from data the model
parameters that measure each language utility for its speakers and the strength
of two biases, the majority preference for their language, and the minority
aversion to it. The values of these two biases decide which language is the
fastest growing in the competition and what would be the stable state of the
system. We also study the system convergence time to stable states and discover
the existence of tipping points with multiple attractors. Moreover, the
critical slowdown of convergence to the stable fractions of language users
appears near and peaks at the tipping points, signaling when the system
approaches them. Our analysis furthers our understanding of multiple language
evolution and the role of tipping points in behavioral transitions. These
insights may help to protect languages from extinction and retain the language
and cultural diversity.Comment: 13 pages, 6 figure
True Nonlinear Dynamics from Incomplete Networks
We study nonlinear dynamics on complex networks. Each vertex has a state
which evolves according to a networked dynamics to a steady-state
. We develop fundamental tools to learn the true steady-state of a small
part of the network, without knowing the full network. A naive approach and the
current state-of-the-art is to follow the dynamics of the observed partial
network to local equilibrium. This dramatically fails to extract the true
steady state. We use a mean-field approach to map the dynamics of the unseen
part of the network to a single node, which allows us to recover accurate
estimates of steady-state on as few as 5 observed vertices in domains ranging
from ecology to social networks to gene regulation. Incomplete networks are the
norm in practice, and we offer new ways to think about nonlinear dynamics when
only sparse information is available.Comment: AAAI 2020, 9 pages, 5 figure
FIELD TEST ON THE COOPERATION OF NSM STRENGTHENING AND EXTERNAL TENDON RETROFITTING TECHNIQUE
In this paper, post-tension and steel plate near-surface mounted (NSM) strengthening systems are proposed to strengthen deteriorated and cracked large box girder rigid frame bridge without altering appearance and dimension of the bridge. The reinforcement method mainly improves the bearing capacity through external prestressed tendons, and bonding steel plate can enhance the shear resistance of the bridge. The main purpose is to study the structural mechanical properties before and after the reinforcement of rigid frame bridges. Take a 540m rigid frame box girder bridge as an example. The static load test of the bridge before and after reinforcement is carried out. The deflection and strain of the middle cross section of the span are measured in the static test. A finite element analysis model was also developed and verified static loading test data. The results show that structural bearing capacity and performance of the bridge were enhanced with the post-tension and NSM strengthening systems cooperatively
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