37,836 research outputs found
A numerical technique for analysis of wave drag at lifting conditions
Numerical technique for analysis of wave drag at lifting conditions for supersonic aircraf
Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 3: Direct energy conversion cycles
For abstract, see N76-23680
Current fluctuations in stochastic systems with long-range memory
We propose a method to calculate the large deviations of current fluctuations
in a class of stochastic particle systems with history-dependent rates.
Long-range temporal correlations are seen to alter the speed of the large
deviation function in analogy with long-range spatial correlations in
equilibrium systems. We give some illuminating examples and discuss the
applicability of the Gallavotti-Cohen fluctuation theorem.Comment: 10 pages, 1 figure. v2: Minor alterations. v3: Very minor alterations
for consistency with published version appearing at
http://stacks.iop.org/1751-8121/42/34200
Rule Managed Reporting in Energy Controlled Wireless Sensor Networks
This paper proposes a technique to extend the network lifetime of a wireless sensor network, whereby each sensor node decides its network involvement, based on energy resources and the information in each message (ascertained through a system of rules). Results obtained from the simulation of an industrial monitoring scenario have shown that a considerable increase in the lifetime and connectivity can be obtained
Energy Harvesting and Management for Wireless Autonomous Sensors
Wireless autonomous sensors that harvest ambient energy are attractive solutions, due to their convenience and economic benefits. A number of wireless autonomous sensor platforms which consume less than 100?W under duty-cycled operation are available. Energy harvesting technology (including photovoltaics, vibration harvesters, and thermoelectrics) can be used to power autonomous sensors. A developed system is presented that uses a photovoltaic module to efficiently charge a supercapacitor, which in turn provides energy to a microcontroller-based autonomous sensing platform. The embedded software on the node is structured around a framework in which equal precedent is given to each aspect of the sensor node through the inclusion of distinct software stacks for energy management and sensor processing. This promotes structured and modular design, allowing for efficient code reuse and encourages the standardisation of interchangeable protocols
Resource Aware Sensor Nodes in Wireless Sensor Networks
Wireless sensor networks are continuing to receive considerable research interest due, in part, to the range of possible applications. One of the greatest challenges facing researchers is in overcoming the limited network lifetime inherent in the small locally powered sensor nodes. In this paper, we propose IDEALS, a system to manage a wireless sensor network using a combination of information management, energy harvesting and energy monitoring, which we label resource awareness. Through this, IDEALS is able to extend the network lifetime for important messages, by controlling the degradation of the network to maximise information throughput
A model for the accidental catalysis of protein unfolding in vivo
Activated processes such as protein unfolding are highly sensitive to
heterogeneity in the environment. We study a highly simplified model of a
protein in a random heterogeneous environment, a model of the in vivo
environment. It is found that if the heterogeneity is sufficiently large the
total rate of the process is essentially a random variable; this may be the
cause of the species-to-species variability in the rate of prion protein
conversion found by Deleault et al. [Nature, 425 (2003) 717].Comment: 5 pages, 2 figure
On a random walk with memory and its relation to Markovian processes
We study a one-dimensional random walk with memory in which the step lengths
to the left and to the right evolve at each step in order to reduce the
wandering of the walker. The feedback is quite efficient and lead to a
non-diffusive walk. The time evolution of the displacement is given by an
equivalent Markovian dynamical process. The probability density for the
position of the walker is the same at any time as for a random walk with
shrinking steps, although the two-time correlation functions are quite
different.Comment: 10 pages, 4 figure
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