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71.
Serge Zaugg Mike van der Schaar Ludwig Houégnigan Michel André 《Applied Acoustics》2012,73(3):281-290
Acquisition of acoustic data from ocean observatories is expected to play a key role for the long-term monitoring of marine mammals and anthropogenic noise. It typically requires processing of a large volume of acoustic data and it must rely on automated identification of signals. We present an algorithmic framework for the detection of short tonal sounds (e.g. cetacean calls, anthropogenic pings) intended to act as a first stage in a system for the automated real-time detection, classification, and localisation of acoustic sources. The algorithm was validated under a diversity of scenarios expected at ocean observatories. Using simulated signals that emulate a variety of cetacean call-types, perfect identification of signal position was obtained for signal to noise ratios of ?15 to ?5 dB, depending on the signal-type. Separation of real-world data segments with short tonal sounds (mainly cetacean calls) from segments with other sounds or noise resulted in Area Under the ROC Curve values between 0.96 and 0.98. The algorithm can be used to automatically identify cetacean calls and anthropogenic short tonal sounds much faster than in real-time, thereby reducing the burden put on data transmission, storage, or processing by classification and localisation algorithms. 相似文献
72.
We propose a general study of the convergence of a Hermite subdivision scheme ℋ of degree d>0 in dimension 1. This is done by linking Hermite subdivision schemes and Taylor polynomials and by associating a so-called
Taylor subdivision (vector) scheme
. The main point of investigation is a spectral condition. If the subdivision scheme of the finite differences of
is contractive, then
is C
0 and ℋ is C
d
. We apply this result to two families of Hermite subdivision schemes. The first one is interpolatory; the second one is a
kind of corner cutting. Both of them use the Tchakalov-Obreshkov interpolation polynomial.
相似文献
73.
Given two graphs and , a graph is -free if it contains no induced subgraph isomorphic to or . Let and be the path on vertices and the cycle on vertices, respectively. In this paper we show that for any -free graph it holds that , where and are the chromatic number and clique number of , respectively. Our bound is attained by several graphs, for instance, the 5-cycle, the Petersen graph, the Petersen graph with an additional universal vertex, and all -critical -free graphs other than (see Hell and Huang [Discrete Appl. Math. 216 (2017), pp. 211–232]). The new result unifies previously known results on the existence of linear -binding functions for several graph classes. Our proof is based on a novel structure theorem on -free graphs that do not contain clique cutsets. Using this structure theorem we also design a polynomial time -approximation algorithm for coloring -free graphs. Our algorithm computes a coloring with colors for any -free graph in time. 相似文献
74.
The solution of a stationary boundary value problem on a domain with conical points has singularities near these points. Here we first consider existence results in appropriate weighted Sobolev spaces in order to incorporate the singularities. We secondly use these results to prove existence, uniqueness and regularity of solutions of non-autonomous second order evolution equations on such domains. 相似文献
75.
B. Sitamtze Youmbi Serge Zékeng Samuel Domngang Florent Calvayrac Alain Bulou 《Ionics》2012,18(4):371-377
To date, the fastest lithium ion-conducting solid electrolytes known are the perovskite-type ABO3 oxide, with A = Li, La and B = Ti, lithium lanthanum titanate (LLTO)
Li3x La( 2 \mathord