| 1. |
- Eriksson, T., et al.
(författare)
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Successive Encoding of Correlated Sources
- 1982
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The encoding of a discrete memoryless multiple source for reconstruction of a sequence with is considered. We require that the encoding should be such that is encoded first without any consideration of , while in a seeond part of the encoding this latter sequence is encoded based on knowledge of the outcome of the first encoding. The resulting scheme is called successive encoding. We find general outer and inner bounds for the corresponding set of achievable rates along with a complete single letter characterization for the special case . Comparisons with the Slepian-Wolf problem [3] and the Ahlswede-Körner-Wyner side information problem [2 ], [9) are carried out.
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| 2. |
- Boström, Anders E, 1951, et al.
(författare)
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Transmission and reflection of electromagnetic waves by an obstacle inside a waveguide
- 1981
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 52, s. 1187-1196
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Tidskriftsartikel (refereegranskat)abstract
- We consider the transmission and reflection of electromagnetic waves by an obstacle inside a waveguide. The method employed is an adaptation of the null‐field approach (T‐matrix method). The geometry is more or less arbitrary, but only for a waveguide with constant cross section can we obtain the scattered field in a not too formal way. For a circular cross section we derive comparatively explicit expressions for the transmission and reflection coefficients of the obstacle, and we give numerical results for spherical and spheroidal obstacles in rotationally symmetric geometries. As an important part of the theory, we have derived some apparently new transformations between the cylindrical and spherical vector waves and also expansions of the free‐space Green’s dyadic in cylindrical vector waves.
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| 3. |
- Karlsson, Anders, et al.
(författare)
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Constitutive relations, dissipation and reciprocity for the Maxwell equations in the time domain
- 1989
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main goal of this paper is to establish general constitutive relations for the electromagnetic fields E,D,B and H in a time domain setting. The four basic assumptions of the medium are linearity, invariance to time translations, causality and continuity. These four assumptions imply that the constitutive relations are convolutions of Riemann-Stieltjes type. A review of the classifi- cation of media in bianisotropic, biisotropic, anisotropic and isotropic media, respectively, is made. Dissipation and reciprocity are defined and the constraints these concepts make on the constitutive relations are analyzed in detail. Furthermore, an appropriate form of time reversal and functions of positive type are introduced and some consequences of these concepts are showed.
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| 4. |
- Karlsson, Anders, et al.
(författare)
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Wave splitting in the time domain for a radially symmetric geometry
- 1989
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A decomposition of the field of the wave equation in three dimensions is suggested. This wave splitting decomposes the field into two components such that in free space simple propagation properties are obtained. The inhomogeneous region is assumed to have a phase velocity variation that varies only in the radial coordinate r from the origin. The suggested wave splitting is a generalization of the wave splitting concept in one spatial dimension. Specifically, the propagation properties in free space in the three-dimensional wave splitting are very analogous to the corresponding propagation properties in free space in one dimension. The three-dimensional decomposition is illustrated in an example of scattering by a sound-soft sphere of radius a.
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| 5. |
- Lundin, Richard
(författare)
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A general power-series expansion method for scalar analysis of the guided modes in an optical fiber
- 1987
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A power-series expansion method for approximate analysis of the guided modes in a cylindrical, radially inhomogeneous dielectric waveguide is presented. The method is developed for a piece-wise polynominal permittivity profile. The solution of the scalar wave equation is constructed by a sequence of power-series expantions. Convergence is ensured and accuracy maintained by regulating the distance (= the steplength ) between successive expansion points. It is demonstrated, by analytical reasoning and numerical examples, that a short steplength is insufficient. The characteristic equation and the cutoff condition are expressed in a unified manner. The method presented is competetive in terms of accuracy achieved and computing time required.
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| 6. |
- Lundin, Richard
(författare)
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A handbook formula for the inductance of a single-layer circular coil
- 1985
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Ingår i: Proceedings of the IEEE. - 0018-9219. ; 73:9, s. 9-1428
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Tidskriftsartikel (refereegranskat)abstract
- A compact six-figure approximation formula for the inductance of a cylindrical current sheet is presented. The formula displays the correct asymptotic behavior in the respective cases of very long and very short coils. The efficiency of the approximation formula is due to a thorough analysis of the exact formula.
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| 7. |
- Lundin, Richard
(författare)
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Efficient approximation of the inductance of a cylindrical current sheet
- 1984
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report comprises the article "Efficient approximation of the inductance of a cylindrical current sheet" and two supplementary sections. The first section treats the question of how to calculate the inductance of a coil. The second section is aimed at providing a theoretical background to the computed approximations of the article. The second section is also intended to demonstrate that the efficiency of the approximated computations is the result of a systematic approach.
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