720 research outputs found
From LTL and Limit-Deterministic B\"uchi Automata to Deterministic Parity Automata
Controller synthesis for general linear temporal logic (LTL) objectives is a
challenging task. The standard approach involves translating the LTL objective
into a deterministic parity automaton (DPA) by means of the Safra-Piterman
construction. One of the challenges is the size of the DPA, which often grows
very fast in practice, and can reach double exponential size in the length of
the LTL formula. In this paper we describe a single exponential translation
from limit-deterministic B\"uchi automata (LDBA) to DPA, and show that it can
be concatenated with a recent efficient translation from LTL to LDBA to yield a
double exponential, \enquote{Safraless} LTL-to-DPA construction. We also report
on an implementation, a comparison with the SPOT library, and performance on
several sets of formulas, including instances from the 2016 SyntComp
competition
Genetic and Neuroanatomical Support for Functional Brain Network Dynamics in Epilepsy
Focal epilepsy is a devastating neurological disorder that affects an
overwhelming number of patients worldwide, many of whom prove resistant to
medication. The efficacy of current innovative technologies for the treatment
of these patients has been stalled by the lack of accurate and effective
methods to fuse multimodal neuroimaging data to map anatomical targets driving
seizure dynamics. Here we propose a parsimonious model that explains how
large-scale anatomical networks and shared genetic constraints shape
inter-regional communication in focal epilepsy. In extensive ECoG recordings
acquired from a group of patients with medically refractory focal-onset
epilepsy, we find that ictal and preictal functional brain network dynamics can
be accurately predicted from features of brain anatomy and geometry, patterns
of white matter connectivity, and constraints complicit in patterns of gene
coexpression, all of which are conserved across healthy adult populations.
Moreover, we uncover evidence that markers of non-conserved architecture,
potentially driven by idiosyncratic pathology of single subjects, are most
prevalent in high frequency ictal dynamics and low frequency preictal dynamics.
Finally, we find that ictal dynamics are better predicted by white matter
features and more poorly predicted by geometry and genetic constraints than
preictal dynamics, suggesting that the functional brain network dynamics
manifest in seizures rely on - and may directly propagate along - underlying
white matter structure that is largely conserved across humans. Broadly, our
work offers insights into the generic architectural principles of the human
brain that impact seizure dynamics, and could be extended to further our
understanding, models, and predictions of subject-level pathology and response
to intervention
Hearing What You Cannot See: Acoustic Vehicle Detection Around Corners
This work proposes to use passive acoustic perception as an additional
sensing modality for intelligent vehicles. We demonstrate that approaching
vehicles behind blind corners can be detected by sound before such vehicles
enter in line-of-sight. We have equipped a research vehicle with a roof-mounted
microphone array, and show on data collected with this sensor setup that wall
reflections provide information on the presence and direction of occluded
approaching vehicles. A novel method is presented to classify if and from what
direction a vehicle is approaching before it is visible, using as input
Direction-of-Arrival features that can be efficiently computed from the
streaming microphone array data. Since the local geometry around the
ego-vehicle affects the perceived patterns, we systematically study several
environment types, and investigate generalization across these environments.
With a static ego-vehicle, an accuracy of 0.92 is achieved on the hidden
vehicle classification task. Compared to a state-of-the-art visual detector,
Faster R-CNN, our pipeline achieves the same accuracy more than one second
ahead, providing crucial reaction time for the situations we study. While the
ego-vehicle is driving, we demonstrate positive results on acoustic detection,
still achieving an accuracy of 0.84 within one environment type. We further
study failure cases across environments to identify future research directions.Comment: Accepted to IEEE Robotics & Automation Letters (2021), DOI:
10.1109/LRA.2021.3062254. Code, Data & Video:
https://github.com/tudelft-iv/occluded_vehicle_acoustic_detectio
Pericardial Tamponade in Acute Myeloid Leukemia
We are reporting a case of acute myeloid leukemia in a child with pericardial effusion and cardiac tamponade, with a review of the literature. Morphologic and cytochemical evidence was used to diagnose acute myeloid leukemia, and radiologic, electrocardiographic, echocardiographic, cytologic, and histologic evidence confirmed the diagnosis of tamponade and pericardial leukemic involvement. Pericardiotomy and pericardial window drainage successfully relieved the tamponade, and conventional chemotherapy was used to induce a remission
Test for interlayer coherence in a quasi-two-dimensional superconductor
Peaks in the magnetoresistivity of the layered superconductor
-(BEDT-TTF)Cu(NCS), measured in fields T applied
within the layers, show that the Fermi surface is extended in the interlayer
direction and enable the interlayer transfer integral (
meV) to be deduced. However, the quasiparticle scattering rate is
such that , implying that
-(BEDT-TTF)Cu(NCS) meets the criterion used to identify
interlayer incoherence. The applicability of this criterion to anisotropic
materials is thus shown to be questionable.Comment: 5 pages, 4 figure
Coexistence of s-wave Superconductivity and Antiferromagnetism
We study the phase diagram of a new model that exhibits a first order
transition between s-wave superconducting and antiferromagnetic phases. The
model, a generalized Hubbard model augmented with competing spin-spin and
pair-pair interactions, was investigated using the projector Quantum Monte
Carlo method. Upon varying the Hubbard from attractive to repulsive we find
a first order phase transition between superconducting and antiferromagnetic
states.Comment: 4 page
Efficient Online Timed Pattern Matching by Automata-Based Skipping
The timed pattern matching problem is an actively studied topic because of
its relevance in monitoring of real-time systems. There one is given a log
and a specification (given by a timed word and a timed automaton
in this paper), and one wishes to return the set of intervals for which the log
, when restricted to the interval, satisfies the specification
. In our previous work we presented an efficient timed pattern
matching algorithm: it adopts a skipping mechanism inspired by the classic
Boyer--Moore (BM) string matching algorithm. In this work we tackle the problem
of online timed pattern matching, towards embedded applications where it is
vital to process a vast amount of incoming data in a timely manner.
Specifically, we start with the Franek-Jennings-Smyth (FJS) string matching
algorithm---a recent variant of the BM algorithm---and extend it to timed
pattern matching. Our experiments indicate the efficiency of our FJS-type
algorithm in online and offline timed pattern matching
Evidence for structural and electronic instabilities at intermediate temperatures in -(BEDT-TTF)X for X=Cu[N(CN)]Cl, Cu[N(CN)]Br and Cu(NCS): Implications for the phase diagram of these quasi-2D organic superconductors
We present high-resolution measurements of the coefficient of thermal
expansion of the quasi-twodimensional
(quasi-2D) salts -(BEDT-TTF)X with X = Cu(NCS), Cu[N(CN)]Br
and Cu[N(CN)]Cl. At intermediate temperatures (B), distinct anomalies
reminiscent of second-order phase transitions have been found at
K and 45 K for the superconducting X = Cu(NCS) and Cu[N(CN)]Br salts,
respectively. Most interestingly, we find that the signs of the uniaxial
pressure coefficients of are strictly anticorrelated with those of
. We propose that marks the transition to a spin-density-wave
(SDW) state forming on minor, quasi-1D parts of the Fermi surface. Our results
are compatible with two competing order parameters that form on disjunct
portions of the Fermi surface. At elevated temperatures (C), all compounds show
anomalies that can be identified with a kinetic, glass-like
transition where, below a characteristic temperature , disorder in the
orientational degrees of freedom of the terminal ethylene groups becomes frozen
in. We argue that the degree of disorder increases on going from the X =
Cu(NCS) to Cu[N(CN)]Br and the Cu[N(CN)]Cl salt. Our results
provide a natural explanation for the unusual time- and cooling-rate
dependencies of the ground-state properties in the hydrogenated and deuterated
Cu[N(CN)]Br salts reported in the literature.Comment: 22 pages, 7 figure
A statistical model for the intrinsically broad superconducting to normal transition in quasi-two-dimensional crystalline organic metals
Although quasi-two-dimensional organic superconductors such as
-(BEDT-TTF)Cu(NCS) seem to be very clean systems, with apparent
quasiparticle mean-free paths of several thousand \AA, the superconducting
transition is intrinsically broad (e.g K wide for K).
We propose that this is due to the extreme anisotropy of these materials, which
greatly exacerbates the statistical effects of spatial variations in the
potential experienced by the quasiparticles. Using a statistical model, we are
able to account for the experimental observations. A parameter , which
characterises the spatial potential variations, may be derived from
Shubnikov-de Haas oscillation experiments. Using this value, we are able to
predict a transition width which is in good agreement with that observed in MHz
penetration-depth measurements on the same sample.Comment: 8 pages, 2 figures, submitted to J. Phys. Condens. Matte
Phytochemical screening of Saye, a traditional herbal remedy for malaria
phytochemical assay was conducted to establish the chemical profile of âSayeâ, a mixture of leaf of Cassia alata, root of Cochlospermum planchonii and whole plant of Phyllantus amarus, used as antimarial remedy. Water and organic extracts were prepared. Characterization of phytoconstituents using specific chemical reagents was performed in tubes, by thin layer chromatography and by high performance liquid chromatography. Steroids and/or triterpenes, cathechic tannins were identified in the decocted and the macerated water extracts of âSayeâ. An anthraquinone with a retention time Rt corresponding to 3.34 min was identified by the HPLC analysis.© 2015 International Formulae Group. All rights reserved.Keywords: Chemical profile, anthraquinones, steroids, triterpenes, tannins
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