2,386 research outputs found
Before the Morning After
This paper presents a wearable biopatch prototype for body surface potential measurement. It combines three key technologies, including mixed-signal system on chip (SoC) technology, inkjet printing technology, and anisotropic conductive adhesive (ACA) bonding technology. An integral part of the biopatch is a low-power low-noise SoC. The SoC contains a tunable analog front end, a successive approximation register analog-to-digital converter, and a reconfigurable digital controller. The electrodes, interconnections, and interposer are implemented by inkjet-printing the silver ink precisely on a flexible substrate. The reliability of printed traces is evaluated by static bending tests. ACA is used to attach the SoC to the printed structures and form the flexible hybrid system. The biopatch prototype is light and thin with a physical size of 16 cm x 16 cm. Measurement results show that low-noise concurrent electrocardiogram signals from eight chest points have been successfully recorded using the implemented biopatch.QC 20130805. Updated from accepted to published.</p
PSO-embedded adaptive Kriging surrogate model method for structural reliability analysis with small failure probability
In the present study, a novel adaptive surrogate model method is proposed for
the analysis of structural reliability with small failure probability. In order
to address the problems with conventional adaptive Kriging surrogate model
method based on candidate sample pool, the adaptive Kriging surrogate model
method which integrates Particle Swarm Optimization algorithm (PSO) is put
forward. In the course of implementation, the surrogate model is gradually
improved through an iterative process and the high-value samples are selected
to update the surrogate model through an optimization solution carried out by
using PSO. Numerical examples are used to evaluate the computational
performance of the proposed method, and a further discussion is conducted
around the revision to the learning function. The results show that the
introduction of PSO not only increases the possibility of obtaining high-value
samples, but also significantly improves the solution accuracy of the adaptive
Kriging surrogate model method for structural reliability analysis. Meanwhile,
the proposed method overcomes the problem caused by the conventional candidate
pool-based selection method through the optimization algorithm to determine
high-value samples, achieving an excellent performance in dealing with the
small failure probability. In addition, the proposed method is applicable to
achieve a reasonable balance between solution accuracy and efficiency through
the revised learning function which takes into account local neighborhood
effects
The extremal unicyclic graphs of the revised edge Szeged index with given diameter
Let be a connected graph. The revised edge Szeged index of is defined
as , where
(resp., ) is the number of edges whose distance to
vertex (resp., ) is smaller than the distance to vertex (resp.,
), and is the number of edges equidistant from both ends of
, respectively. In this paper, the graphs with minimum revised edge Szeged
index among all the unicyclic graphs with given diameter are characterized.Comment: arXiv admin note: text overlap with arXiv:1805.0657
Tree maps having chain movable fixed points
AbstractIn this paper we discuss some basic properties of chain reachable sets and chain equivalent sets of continuous maps. It is proved that if f:T→T is a tree map which has a chain movable fixed point v, and the chain equivalent set CE(v,f) is not contained in the set P(f) of periodic points of f, then there exists a positive integer p not greater than the number of points in the set End([CE(v,f)])−Pv(f) such that fp is turbulent, and the topological entropy h(f)⩾(log2)/p. This result generalizes the corresponding results given in Block and Coven (1986) [2], Guo et al. (2003) [6], Sun and Liu (2003) [10], Ye (2000) [11], Zhang and Zeng (2004) [12]. In addition, in this paper we also consider metric spaces which may not be trees but have open subsets U such that the closures U¯ are trees. Maps of such metric spaces which have chain movable fixed points are discussed
Quantum Discord for Investigating Quantum Correlations without Entanglement in Solids
Quantum systems unfold diversified correlations which have no classical
counterparts. These quantum correlations have various different facets. Quantum
entanglement, as the most well known measure of quantum correlations, plays
essential roles in quantum information processing. However, it has recently
been pointed out that quantum entanglement cannot describe all the
nonclassicality in the correlations. Thus the study of quantum correlations in
separable states attracts widely attentions. Herein, we experimentally
investigate the quantum correlations of separable thermal states in terms of
quantum discord. The sudden change of quantum discord is observed, which
captures ambiguously the critical point associated with the behavior of
Hamiltonian. Our results display the potential applications of quantum
correlations in studying the fundamental properties of quantum system, such as
quantum criticality of non-zero temperature.Comment: 4 pages, 4 figure
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