1,902 research outputs found
FTT-Ethernet: A Flexible Real-Time Communication Protocol that Supports Dynamic QoS Management on Ethernet-based Systems
Ethernet was not originally developed to meet the
requirements of real-time industrial automation systems and
it was commonly considered unsuited for applications at the
field level. Hence, several techniques were developed to make
this protocol exhibit real-time behavior, some of them requiring
specialized hardware, others providing soft-real-time guarantees
only, or others achieving hard real-time guarantees with
different levels of bandwidth efficiency. More recently, there has
been an effort to support quality-of-service (QoS) negotiation
and enforcement but there is not yet an Ethernet-based data
link protocol capable of providing dynamic QoS management
to further exploit the variable requirements of dynamic applications.
This paper presents the FTT-Ethernet protocol, which
efficiently supports hard-real-time operation in a flexible way,
seamlessly over shared or switched Ethernet. The FTT-Ethernet
protocol employs an efficient master/multislave transmission
control technique and combines online scheduling with online
admission control, to guarantee continued real-time operation
under dynamic communication requirements, together with data
structures and mechanisms that are tailored to support dynamic
QoS management. The paper includes a sample application,
aiming at the management of video streams, which highlights
the protocolâs ability to support dynamic QoS management with
real-time guarantees
Lowering of surface melting temperature in atomic clusters with a nearly closed shell structure
We investigate the interplay of particle number, N, and structural properties
of selected clusters with N=12 up to N=562 by employing Gupta potentials
parameterized for Aluminum and extensive Monte-Carlo simulations. Our analysis
focuses on closed shell structures with extra atoms. The latter can put the
cluster under a significant stress and we argue that typically such a strained
system exhibits a reduced energy barrier for (surface) diffusion of cluster
atoms. Consequently, also its surface melting temperature, T_S, is reduced, so
that T_S separates from and actually falls well below the bulk value. The
proposed mechanism may be responsible for the suppression of the surface
melting temperature observed in a recent experiments.Comment: 9 pages, 7 figures, 1 table, REVTeX 4; submitted to Phys.Rev.
Arbuscular Mycorrhizal Fungi Diversity and Contribution to Crop Growth in Agricultural Fields
Symposium Pape
Nanodiamonds-induced effects on neuronal firing of mouse hippocampal microcircuits
Fluorescent nanodiamonds (FND) are carbon-based nanomaterials that can
efficiently incorporate optically active photoluminescent centers such as the
nitrogen-vacancy complex, thus making them promising candidates as optical
biolabels and drug-delivery agents. FNDs exhibit bright fluorescence without
photobleaching combined with high uptake rate and low cytotoxicity. Focusing on
FNDs interference with neuronal function, here we examined their effect on
cultured hippocampal neurons, monitoring the whole network development as well
as the electrophysiological properties of single neurons. We observed that FNDs
drastically decreased the frequency of inhibitory (from 1.81 Hz to 0.86 Hz) and
excitatory (from 1.61 Hz to 0.68 Hz) miniature postsynaptic currents, and
consistently reduced action potential (AP) firing frequency (by 36%), as
measured by microelectrode arrays. On the contrary, bursts synchronization was
preserved, as well as the amplitude of spontaneous inhibitory and excitatory
events. Current-clamp recordings revealed that the ratio of neurons responding
with AP trains of high-frequency (fast-spiking) versus neurons responding with
trains of low-frequency (slow-spiking) was unaltered, suggesting that FNDs
exerted a comparable action on neuronal subpopulations. At the single cell
level, rapid onset of the somatic AP ("kink") was drastically reduced in
FND-treated neurons, suggesting a reduced contribution of axonal and dendritic
components while preserving neuronal excitability.Comment: 34 pages, 9 figure
Experimental Observation of Energy Modulation in Electron Beams Passing Through Terahertz Dielectric Wakefield Structures
We report observation of a strong wakefield induced energy modulation in an
energy-chirped electron bunch passing through a dielectric-lined waveguide.
This modulation can be effectively converted into a spatial modulation forming
micro-bunches with a periodicity of 0.5 - 1 picosecond, hence capable of
driving coherent THz radiation. The experimental results agree well with
theoretical predictions.Comment: v3. Reviewers' suggestions incorporated. Accepted by PR
Calibrating accelerometer tags with oxygen consumption rate of rainbow trout (Oncorhynchus mykiss) and their use in aquaculture facility: A case study
SIMPLE SUMMARY: Measuring metabolic rates in free-swimming fish would provide valuable insights about the energetic costs of different life activities this is challenging to implement in the field due to the difficulty of performing such measurements. Thus, the calibration of acoustic transmitters with the oxygen consumption rate (MO(2)) could be promising to counter the limitations observed in the field. In this study, calibrations were performed in rainbow trout (Oncorhynchus mykiss), and a subsample of fish was implanted with such a transmitter and then followed under aquaculture conditions. The use of acoustic transmitters calibrated with MO(2) appeared to be a promising tool to estimate energetic costs in free-swimming rainbow trout, and for welfare assessment in the aquaculture industry. ABSTRACT: Metabolic rates are linked to the energetic costs of different activities of an animalâs life. However, measuring the metabolic rate in free-swimming fish remains challenging due to the lack of possibilities to perform these direct measurements in the field. Thus, the calibration of acoustic transmitters with the oxygen consumption rate (MO(2)) could be promising to counter these limitations. In this study, rainbow trout (Oncorhynchus mykiss Walbaum, 1792; n = 40) were challenged in a critical swimming test (U(crit)) to (1) obtain insights about the aerobic and anaerobic metabolism throughout electromyograms; and (2) calibrate acoustic transmittersâ signal with the MO(2) to be later used as a proxy of energetic costs. After this calibration, the fish (n = 12) were implanted with the transmitter and were followed during ~50 days in an aquaculture facility, as a case study, to evaluate the potential of such calibration. Accelerometer data gathered from tags over a long time period were converted to estimate the MO(2). The MO(2) values indicated that all fish were reared under conditions that did not impact their health and welfare. In addition, a diurnal pattern with higher MO(2) was observed for the majority of implanted trout. In conclusion, this study provides (1) biological information about the muscular activation pattern of both red and white muscle; and (2) useful tools to estimate the energetic costs in free-ranging rainbow trout. The use of acoustic transmitters calibrated with MO(2), as a proxy of energy expenditure, could be promising for welfare assessment in the aquaculture industry
Introduction
This chapter provides an overview of the book theme, motivating the need for high-performance and time-predictable embedded computing. It describes the challenges introduced by the need for time-predictability on the one hand, and high-performance on the other, discussing on a high level how these contradictory requirements can be simultaneously supported
Sovereign debt restructuring : the judge, the vultures and creditor rights
What role did the US courts play in the Argentine debt swap of 2005? What implications does this have for the future of creditor rights in sovereign bond markets?
The judge in the Argentine case has, it appears, deftly exploited creditor heterogeneity â between holdouts seeking capital gains and institutional investors wanting a settlement â to promote a swap with a supermajority of creditors. Our analysis of Argentine debt litigation reveals a âjudge-mediatedâ sovereign debt restructuring, which resolves the key issues of Transition and Aggregation - two of the tasks envisaged for the IMFâs still-born Sovereign Debt Restructuring Mechanism.
For the future, we discuss how judge-mediated sovereign debt restructuring (together with creditor committees) could complement the alternative promoted by the US Treasury, namely collective action clauses in sovereign bond contracts
- âŠ