| 51. |
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| 52. |
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| 53. |
- Behrends, Sönke, 1976, et al.
(författare)
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The effect of fast transhipment technology on the potential for intermodal freight transport
- 2010
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Ingår i: Selected proceedings of the 12th World Conference on Transport Research Society. - 9789899698611
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Konferensbidrag (refereegranskat)abstract
- Traditionally, intermodal transport has a medium to high market share for large flows over long distances while the short and medium distances (less than 500km) mainly remain a domain of the road transport sector. In order to allow intermodal transport to compete in the medium distance and high quality market segment, alternative network operations that allow for an intensification of rail services and expansion of geographical coverage are needed. Intermodal liner trains that operate in corridor network designs with intermediate stops between start and end terminals are regularly advocated by intermodal transport researchers as a means to compete with all-road transport on small volumes and short distance markets. Innovative transhipment technologies facilitating fast and efficient transhipments are a necessity for intermodal liner trains since the conventional terminals are not appropriate for intermediate terminals where freight volumes are low and train dwelling times need to be short. The purpose of this paper is to analyse the transhipment unit cost’s effect on the modal shift potential of intermodal liner trains based on fast and efficient transhipments. In a theoretical case study the cost and potential modal share for an intermodal liner train on a corridor in Sweden is analysed. The method is based on modelling a competitive situation between traditional road transport and intermodal road-rail transport. The results confirm that in theory intermodal liner trains can provide competitive services on short and medium transport distances in case transhipment costs are kept low. Fast and efficient transhipment technologies can open business opportunities for operators and cost savings potential for shippers in a market segment which is dominated by road transport.
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| 54. |
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| 55. |
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| 56. |
- Beilina, Larisa, 1970
(författare)
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Adaptive Finite Element Method for an Electromagnetic Coefficient Inverse Problem
- 2010
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Ingår i: AIP Conference Proceedings; International Conference on Numerical Analysis and Applied Mathematics Rhodes, GREECE, SEP 19-25, 2010. - : AIP. - 0094-243X .- 1551-7616. - 9780735408340 ; 1281, s. 1052-1055
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Konferensbidrag (refereegranskat)abstract
- We present an adaptive finite element method for solution of an electromagnetic coefficient inverse problem to reconstruct the dielectric permittivity and magnetic permeability functions. The inverse problem is formulated as an optimal control problem, where we solve the equations of optimality expressing stationarity of an associated Lagrangian by a quasi-Newton method: in each step we compute the gradient by solving a forward and an adjoint equation. We formulate an adaptive algorithm which can be used to efficiently solve electromagnetic coefficient inverse problem.
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| 57. |
- Beilina, Larisa, 1970, et al.
(författare)
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Adaptive Hybrid Finite Element/Difference method for Maxwell's equations
- 2010
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Ingår i: TWMS Journal of Pure and Applied Mathematics. - 1683-3511. ; 1:2, s. 176-197
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Tidskriftsartikel (refereegranskat)abstract
- An explicit, adaptive, hybrid finite element/finite difference method is proposed for the numerical solution of Maxwell’s equations in the time domain. The method is hybrid in the sense that different numerical methods, finite elements and finite differences, are used in different parts of the computational domain. Thus, we combine the flexibility of finite elements with the efficiency of finite differences. Furthermore, an a posteriori error estimate is derived for local adaptivity and error control inside the subregion, where finite elements are used. Numerical experiments illustrate the usefulness of computational adaptive error control of proposed new method.
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| 58. |
- Beilina, Larisa, 1970
(författare)
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Adaptive Hybrid Finite Element/Difference method for Maxwell's equations: an a priory error estimate and efficiency
- 2010
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Ingår i: Applied and Computational Mathematics. - 1683-3511. ; 9:2, s. 176-197
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Tidskriftsartikel (refereegranskat)abstract
- In this work we extend our previous study where anexplicit adaptive hybrid finite element/finite difference method wasproposed for the numerical solution of Maxwell's equations in the timedomain. Here we derive a priori error estimate in finite elementmethod and present numerical examples where we indicate the rate ofconvergence of the hybrid method. We compare also hybrid finiteelement/finite difference method with pure finite element method andshow that we devise an optimized method. In our three dimensionalcomputations the hybrid approach is about 3 times faster than acorresponding highly optimized finite element method. We conclude thatthe hybrid approach may be an important tool to reduce the executiontime and memory requirements for large scale computations.
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| 59. |
- Beilina, Larisa, 1970, et al.
(författare)
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Adaptivity with relaxation for ill-posed problems and global convergence for a coefficient inverse problem
- 2010
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Ingår i: Journal of Mathematical Sciences, JMS, Springer. - : Springer Science and Business Media LLC. - 1072-3374 .- 1573-8795. ; 167:3, s. 279-325
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Tidskriftsartikel (refereegranskat)abstract
- A new framework of the functional analysis is developed for the finite element adaptive method (adaptivity) for the Tikhonov regularization functional for some ill-posed problems. As a result, the relaxation property for adaptive mesh refinements is established. An application to a multidimensional coefficient inverse problem for a hyperbolic equation is discussed. This problem arises in the inverse scattering of acoustic and electromagnetic waves. First, a globally convergent numerical method provides a good approximation for the correct solution of this problem. Next, this approximation is enhanced via the subsequent application of the adaptivity. Analytical results are verified computationally. Bibliography: 30 titles. Illustration: 2 figures.
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| 60. |
- Beilina, Larisa, 1970, et al.
(författare)
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Global convergence for Inverse Problems
- 2010
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Ingår i: AIP Conference Proceedings; International Conference on Numerical Analysis and Applied Mathematics Rhodes, GREECE, SEP 19-25, 2010. - : AIP. - 0094-243X .- 1551-7616. - 9780735408340 ; 1281, s. 1056-1058
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Konferensbidrag (refereegranskat)abstract
- A globally convergent numerical method for a multidimensional Coefficient Inverse Problem for a hyperbolic equation is presented. It is shown that this technique provides a good starting point for the finite element adaptive method (adaptivity). This leads to a natural two-stage numerical procedure, which synthesizes both these methods.
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