465,502 research outputs found
The (a,b,s,t)-diameter of graphs: a particular case of conditional diameter
The conditional diameter of a connected graph is defined as
follows: given a property of a pair of
subgraphs of , the so-called \emph{conditional diameter} or -{\em diameter} measures the maximum distance among subgraphs satisfying
. That is, In this paper we consider the conditional diameter in
which requires that for all , for all , and for some integers and
, where denotes the degree of
a vertex of , denotes the minimum degree and the
maximum degree of . The conditional diameter obtained is called
-\emph{diameter}. We obtain upper bounds on the -diameter by using the -alternating polynomials on the mesh of
eigenvalues of an associated weighted graph. The method provides also bounds
for other parameters such as vertex separators
The fluid mechanics of bubbly drinks
Bubbly drinks are surprisingly attractive. There is something about the
nature of the these beverages that make them preferable among other choices. In
this article we explore the physics involved in this particular kind of
two-phase, mass-transfer-driven flows.Comment: Extended version of Zenit R and Rodr\'iguez-Rodr\'iguez J. The fluid
mechanics of bubbly drinks. Physics Today, Vol. 71(11) pp. 44-50, November
201
A 64-channel inductively-powered neural recording sensor array
This paper reports a 64-channel inductively powered neural recording sensor array. Neural signals are acquired, filtered, digitized and compressed in the channels. Additionally, each channel implements a local auto-calibration mechanism which configures the transfer characteristics of the recording site. The system has two operation modes; in one case the information captured by the channels is sent as uncompressed raw data; in the other, feature vectors extracted from the detected neural spikes are transmitted. Data streams coming from the channels are serialized by an embedded digital processor and transferred to the outside by means of the same inductive link used for powering the system. Simulation results show that the power consumption of the complete system is 377μW.Ministerio de Ciencia e Innovación TEC2009-0844
A power efficient neural spike recording channel with data bandwidth reduction
This paper presents a mixed-signal neural spike recording channel which features, as an added value, a simple and low-power data compression mechanism. The channel uses a band-limited differential low noise amplifier and a binary search data converter, together with other digital and analog blocks for control, programming and spike characterization. The channel offers a self-calibration operation mode and it can be configured both for signal tracking (to raw digitize the acquired neural waveform) and feature extraction (to build a first-order PWL approximation of the spikes). The prototype has been fabricated in a standard CMOS 0.13μm and occupies 400μm×400μm. The overall power consumption of the channel during signal tracking is 2.8μW and increases to 3.0μW average when the feature extraction operation mode is programmed.Ministerio de Ciencia e Innovación TEC2009-08447Junta de Andalucía TIC-0281
Estimation of the modulation index of cpm signals using hos
Three simple methods are proposed for the estimation of the modulation index of continuous phase modulated signals in noise. These methods employ the estimated autocorrelation and fourth-order cumulant sequences of the received signal after sampling at the symbol rate. Analytic expressions are derived for the asymptotic mean and variance of the estimated parameters which are corroborated by means of Monte Carlo simulations. The performance of the methods is illustrated graphically and numerically. It is concluded that, under significant noise degradation, only the scheme based on the fourth-order cumulant sequence can be used to estimate consistently the modulation index h in the range 0(h(1.Peer ReviewedPostprint (published version
Frequency support characteristics of grid-interactive power converters based on the synchronous power controller
Grid-interactive converters with primary frequency control and inertia emulation have emerged and are promising for future renewable generation plants because of the contribution in power system stabilization. This paper gives a synchronous active power control solution for gridinteractive converters , as a way to emulate synchronous generators for inerita characteristics and load sharing. As design considerations, the virtual angle stability and transient response are both analyzed, and the detailed implementation structure is also given without entailing any difficulty in practice. The analytical and experimental validation of frequency support characteristics differentiates the work from other publications on generator emulation control. The 10 kW simulation and experimental frequency sweep tests on a regenerative source test bed present good performance of the proposed control in showing inertia and droop characteristics, as well as the controllable transient response.Peer ReviewedPostprint (author's final draft
Globalización y Estado del bienestar: debates actuales en Europa y Asia. Una presentación
Presentación del III Scientific Congress on the Law of The Philippines and Spain, Málaga, Facultad de Derecho de la Universidad de Málaga, 10-11 de mayo de 2017
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