514 research outputs found
Exact finite elements for conduction and convection
An approach for developing exact one dimensional conduction-convection finite elements is presented. Exact interpolation functions are derived based on solutions to the governing differential equations by employing a nodeless parameter. Exact interpolation functions are presented for combined heat transfer in several solids of different shapes, and for combined heat transfer in a flow passage. Numerical results demonstrate that exact one dimensional elements offer advantages over elements based on approximate interpolation functions
Integrated transient thermal-structural finite element analysis
An integrated thermal structural finite element approach for efficient coupling of transient thermal and structural analysis is presented. Integrated thermal structural rod and one dimensional axisymmetric elements considering conduction and convection are developed and used in transient thermal structural applications. The improved accuracy of the integrated approach is illustrated by comparisons with exact transient heat conduction elasticity solutions and conventional finite element thermal finite element structural analyses
Non-adaptive Heisenberg-limited metrology with multi-channel homodyne measurements
We show a protocol achieving the ultimate Heisenberg-scaling sensitivity in the estimation of a parameter encoded in a generic linear network, without employing any auxiliary networks, and without the need of any prior information on the parameter nor on the network structure. As a result, this protocol does not require a prior coarse estimation of the parameter, nor an adaptation of the network. The scheme we analyse consists of a single-mode squeezed state and homodyne detectors in each of the M output channels of the network encoding the parameter, making it feasible for experimental applications
The interface of gravity and quantum mechanics illuminated by Wigner phase space
We provide an introduction into the formulation of non-relativistic quantum
mechanics using the Wigner phase-space distribution function and apply this
concept to two physical situations at the interface of quantum theory and
general relativity: (i) the motion of an ensemble of cold atoms relevant to
tests of the weak equivalence principle, and (ii) the Kasevich-Chu
interferometer. In order to lay the foundations for this analysis we first
present a representation-free description of the Kasevich-Chu interferometer
based on unitary operators.Comment: 69 pages, 6 figures, minor changes to match the published version.
The original publication is available at
http://en.sif.it/books/series/proceedings_fermi or
http://ebooks.iospress.nl/volumearticle/3809
New factorization algorithm based on a continuous representation of truncated Gauss sums
In this paper, we will describe a new factorization algorithm based on the
continuous representation of Gauss sums, generalizable to orders j>2. Such an
algorithm allows one, for the first time, to find all the factors of a number N
in a single run without precalculating the ratio N/l, where l are all the
possible trial factors. Continuous truncated exponential sums turn out to be a
powerful tool for distinguishing factors from non-factors (we also suggest,
with regard to this topic, to read an interesting paper by S. Woelk et al. also
published in this issue [Woelk, Feiler, Schleich, J. Mod. Opt. in press]) and
factorizing different numbers at the same time. We will also describe two
possible M-path optical interferometers, which can be used to experimentally
realize this algorithm: a liquid crystal grating and a generalized symmetric
Michelson interferometer.Comment: 8 pages, 5 figure
Heisenberg scaling precision in multi-mode distributed quantum metrology
We consider the estimation of an arbitrary parameter φ, such as the temperature or a magnetic field, affecting in a distributed manner the components of an arbitrary linear optical passive network, such as an integrated chip. We demonstrate that Heisenberg scaling precision (i.e. of the order of 1/N, where N is the number of probe photons) can be achieved without any iterative adaptation of the interferometer hardware and by using only a simple, single, squeezed light source and well-established homodyne measurements techniques. Furthermore, no constraint on the possible values of the parameter is needed but only a preliminary shot-noise estimation (i.e. with a precision of) easily achievable without any quantum resources. Indeed, such a classical knowledge of the parameter is enough to prepare a single, suitable optical stage either at the input or the output of the network to monitor with Heisenberg-limited precision any variation of the parameter to the order of without the need to iteratively modify such a stage
Interference mitigation in wireless mesh networks through radio co-location aware conflict graphs
Wireless Mesh Networks (WMNs) have evolved into a wireless communication technology of immense interest. But technological advancements in WMNs have inadvertently spawned a plethora of network performance bottlenecks, caused primarily by the rise in prevalent interference. Conflict Graphs are indispensable tools used to theoretically represent and estimate the interference in wireless networks. We propose a generic algorithm to generate conflict graphs which is independent of the underlying interference model. Further, we propose the notion of radio co-location interference, which is caused and experienced by spatially co-located radios in multi-radio multi-channel WMNs. We experimentally validate the concept, and propose a new all-encompassing algorithm to create a radio co-location aware conflict graph. Our novel conflict graph generation algorithm is demonstrated to be significantly superior and more efficient than the conventional approach, through theoretical interference estimates and comprehensive experiments. The results of an extensive set of ns-3 simulations run on the IEEE 802.11g platform strongly indicate that the radio co-location aware conflict graphs are a marked improvement over their conventional counterparts. We also question the use of total interference degree as a reliable metric to predict the performance of a Channel Assignment scheme in a given WMN deployment
A Cloud Native Solution for Dynamic Auto Scaling of MME in LTE
Due to rapid growth in the use of mobile
devices and as a vital carrier of IoT traffic, mobile networks
need to undergo infrastructure wide revisions to meet explosive
traffic demand. In addition to data traffic, there has
been a significant rise in the control signaling overhead due
to dense deployment of small cells and IoT devices. Adoption
of technologies like cloud computing, Software Defined
Networking (SDN) and Network Functions Virtualization
(NFV) is impressively successful in mitigating the existing
challenges and driving the path towards 5G evolution.
However, issues pertaining to scalability, ease of use, service
resiliency, and high availability need considerable study
for successful roll out of production grade 5G solutions in
cloud. In this work, we propose a scalable Cloud Native
Solution for Mobility Management Entity (CNS-MME) of
mobile core in a production data center based on micro service
architecture. The micro services are lightweight MME
functionalities, in contrast to monolithic MME in Long
Term Evolution (LTE). The proposed architecture is highly
available and supports auto-scaling to dynamically scale-up
and scale-down required micro services for load balancing.
The performance of proposed CNS-MME architecture is
evaluated against monolithic MME in terms of scalability,
auto scaling of the service, resource utilization of MME,
and efficient load balancing features. We observed that,
compared to monolithic MME architecture, CNS-MME
provides 7% higher MME throughput and also reduces
the processing resource consumption by 26%
DYNAMO-MAS: a multi-agent system for ontology evolution from text
International audienceManual ontology development and evolution are complex and time-consuming tasks, even when textual documents are used as knowledge sources in addition to human expertise or existing ontologies. Processing natural language in text produces huge amounts of linguistic data that need to be filtered out and structured. To support both of these tasks, we have developed DYNAMO-MAS, an interactive tool based on an adaptive multi-agent system (adaptive MAS or AMAS) that builds and evolves ontologies from text. DYNA-MO-MAS is a partner system to build ontologies; the ontologist interacts with the system to validate or modify its outputs. This paper presents the architecture of DYNAMO-MAS, its operating principles and its evaluation on three case studies
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