2,064 research outputs found
Synchronization transitions in ensembles of noisy oscillators with bi-harmonic coupling
We describe synchronization transitions in an ensemble of globally coupled
phase oscillators with a bi-harmonic coupling function, and two sources of
disorder - diversity of intrinsic oscillatory frequencies and external
independent noise. Based on the self-consistent formulation, we derive analytic
solutions for different synchronous states. We report on various non-trivial
transitions from incoherence to synchrony where possible scenarios include:
simple supercritical transition (similar to classical Kuramoto model),
subcritical transition with large area of bistability of incoherent and
synchronous solutions, and also appearance of symmetric two-cluster solution
which can coexist with regular synchronous state. Remarkably, we show that the
interplay between relatively small white noise and finite-size fluctuations can
lead to metastable asynchronous solution
Explosive Synchronization is Discontinuous
Spontaneous explosive is an abrupt transition to collective behavior taking
place in heterogeneous networks when the frequencies of the nodes are
positively correlated to the node degree. This explosive transition was
conjectured to be discontinuous. Indeed, numerical investigations reveal a
hysteresis behavior associated with the transition. Here, we analyze explosive
synchronization in star graphs. We show that in the thermodynamic limit the
transition to (and out) collective behavior is indeed discontinuous. The
discontinuous nature of the transition is related to the nonlinear behavior of
the order parameter, which in the thermodynamic limit exhibits multiple fixed
points. Moreover, we unravel the hysteresis behavior in terms of the graph
parameters. Our numerical results show that finite size graphs are well
described by our predictions
Efficient slot labelling
Slot labelling is an essential component of any dialogue system, aiming to
find important arguments in every user turn. Common approaches involve large
pre-trained language models (PLMs) like BERT or RoBERTa, but they face
challenges such as high computational requirements and dependence on
pre-training data. In this work, we propose a lightweight method which performs
on par or better than the state-of-the-art PLM-based methods, while having
almost 10x less trainable parameters. This makes it especially applicable for
real-life industry scenarios
Use of low orbital satellite communications systems for humanitarian programs
Communication and information exchange play a decisive role in progress and social development. However, in many parts of the world the communication infrastructure is inadequate and the capacity for on-line exchange of information may not exist. This is true of underdeveloped countries, remote and relatively inaccessible regions, sites of natural disasters, and of all cases where the resources needed to create complex communication systems are limited. The creation of an inexpensive space communications system to service such areas is therefore a high priority task. In addition to a relatively low-cost space segment, an inexpensive space communications systems requires a large number of ground terminals, which must be relatively inexpensive, energy efficient (using power generated by storage batteries, or solar arrays, etc.), small in size, and must not require highly expert maintenance. The ground terminals must be portable, and readily deployable. Communications satellites in geostationary orbit at altitudes of about 36,000 km are very expensive and require complex and expensive ground stations and launch vehicles. Given current technology, it is categorically impossible to develop inexpensive satellite systems with portable ground terminals using such satellites. To solve the problem of developing an inexpensive satellite communications system that can operate with relatively small ground stations, including portable terminals, we propose to use a system with satellites in low Earth orbit, at an altitude of 900-1500 km. Because low orbital satellites are much closer to the Earth than geostationary ones and require vastly less energy expenditure by the satellite and ground terminals for transmission of messages, a system using them is relatively inexpensive. Such a system could use portable ground terminals no more complex than ordinary mobile police radios
Thermodynamics of network model fitting with spectral entropies
An information theoretic approach inspired by quantum statistical mechanics
was recently proposed as a means to optimize network models and to assess their
likelihood against synthetic and real-world networks. Importantly, this method
does not rely on specific topological features or network descriptors, but
leverages entropy-based measures of network distance. Entertaining the analogy
with thermodynamics, we provide a physical interpretation of model
hyperparameters and propose analytical procedures for their estimate. These
results enable the practical application of this novel and powerful framework
to network model inference. We demonstrate this method in synthetic networks
endowed with a modular structure, and in real-world brain connectivity
networks.Comment: 11 pages, 3 figure
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