9,209 research outputs found
Parallel computing for the finite element method
A finite element method is presented to compute time harmonic microwave
fields in three dimensional configurations. Nodal-based finite elements have
been coupled with an absorbing boundary condition to solve open boundary
problems. This paper describes how the modeling of large devices has been made
possible using parallel computation, New algorithms are then proposed to
implement this formulation on a cluster of workstations (10 DEC ALPHA 300X) and
on a CRAY C98. Analysis of the computation efficiency is performed using simple
problems. The electromagnetic scattering of a plane wave by a perfect electric
conducting airplane is finally given as example
Cost objective PLM and CE
Concurrent engineering taking into account product life-cycle factors seems to be one of the industrial challenges of the next years. Cost estimation and management are two main strategic tasks that imply the possibility of managing costs at the earliest stages of product development. This is why it is indispensable to let people from economics and from industrial engineering collaborates in order to find the best solution for enterprise progress for economical factors mastering. The objective of this paper is to present who we try to adapt costing methods in a PLM and CE point of view to the new industrial context and configuration in order to give pertinent decision aid for product and process choices. A very important factor is related to cost management problems when developing new products. A case study is introduced that presents how product development actors have referenced elements to product life-cycle costs and impacts, how they have an idea bout economical indicators when taking decisions during the progression of the project of product development.
Generalized conditional gradient: analysis of convergence and applications
The objectives of this technical report is to provide additional results on
the generalized conditional gradient methods introduced by Bredies et al.
[BLM05]. Indeed , when the objective function is smooth, we provide a novel
certificate of optimality and we show that the algorithm has a linear
convergence rate. Applications of this algorithm are also discussed
Efficient genetic algorithms for solving hard constrained optimization problems
This paper studies many Genetic Algorithm strategies
to solve hard-constrained optimization problems. It investigates the role of various genetic operators to avoid premature convergence. In particular, an analysis of niching methods is carried out on a simple function to show advantages and drawbacks of each of them. Comparisons are also performed on an original benchmark based on an electrode shape optimization technique coupled with a charge simulation metho
Niching genetic algorithms for optimization in electromagnetics. I. Fundamentals
Niching methods extend genetic algorithms and permit the investigation of multiple optimal solutions in the search space. In this paper, we review and discuss various strategies of niching for optimization in electromagnetics. Traditional mathematical problems and an electromagnetic benchmark are solved using niching genetic algorithms to show their interest in real world optimization
A Construction of Quantum LDPC Codes from Cayley Graphs
We study a construction of Quantum LDPC codes proposed by MacKay, Mitchison
and Shokrollahi. It is based on the Cayley graph of Fn together with a set of
generators regarded as the columns of the parity-check matrix of a classical
code. We give a general lower bound on the minimum distance of the Quantum code
in where d is the minimum distance of the classical code.
When the classical code is the repetition code, we are able to
compute the exact parameters of the associated Quantum code which are .Comment: The material in this paper was presented in part at ISIT 2011. This
article is published in IEEE Transactions on Information Theory. We point out
that the second step of the proof of Proposition VI.2 in the published
version (Proposition 25 in the present version and Proposition 18 in the ISIT
extended abstract) is not strictly correct. This issue is addressed in the
present versio
Raman studies of suspensions and solutions of singlewall carbon nanotubes
Raman spectroscopy is used to probe the structure and electronic properties
of nanotubes dispersed in a liquid phase. We show that the radial breathing
modes are upshifted in suspensions due to the molecular pressure of the
solvent. On the other hand, we directly probe charge transfer in solutions of
nanotube polyelectrolytes and its reversibility after oxydation in air
Framework for Product Lifecycle Management integration in Small and Medium Enterprises networks
In order to improve the performance of extended enterprises, Small and Medium Enterprises (SMEs) must be integrated into the extended networks. This integration must be carried out on several levels which are mastered by the Product Lifecycle Management (PLM). But, PLM is underdeveloped in SMEs mainly because of the difficulties in implementing information systems. This paper aims to propose a modeling framework to facilitate the implementation of PLM systems in SMEs. Our approach proposes a generic model for the creation of processes and data models. These models are explained, based on the scope and framework of the modeling, in order to highlight the improvements provided
Graph Based Reduction of Program Verification Conditions
Increasing the automaticity of proofs in deductive verification of C programs
is a challenging task. When applied to industrial C programs known heuristics
to generate simpler verification conditions are not efficient enough. This is
mainly due to their size and a high number of irrelevant hypotheses. This work
presents a strategy to reduce program verification conditions by selecting
their relevant hypotheses. The relevance of a hypothesis is determined by the
combination of a syntactic analysis and two graph traversals. The first graph
is labeled by constants and the second one by the predicates in the axioms. The
approach is applied on a benchmark arising in industrial program verification
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