| 1. |
- Beckman, Claes, 1962-
(författare)
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Antenna-to-Antenna Isolation Measurements
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this document we show results from measurements of the antenna-to-antenna isolation between different types of base station antenna configurations. The measurements are conducted on antennas for the GSM1800 band. However, since this band is relatively close to the IMT-2000 band it is reasonable to assume similar results for antennas to be used in this band.In this report we present measurement results from antennas with both vertical and slanted dual polarisation, and different horizontal beamwidths. The different antennas are shown in Table 1. The isolation is measured with the antennas positioned for some different configurations.
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| 2. |
- Beckman, Claes, 1962-, et al.
(författare)
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Radio Propagation in Curved Road Tunnels
- 1998
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Ingår i: Nordic Radio Symposium on Broadband Radio Access, NRS98 (Saltsjöbaden), 1998.. ; , s. 41-46
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This report investigates radio propagation in curved road tunnels at a mobile communications frequency of 925 MHz. This is done by comparing simulations with measurements taken in Norwegian road tunnels. The simulations are based on a simple model derived from geometrical optics and hybrid waveguide modes. The simulations agree well with measurements, indicating that the proposed model is reasonably good.
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| 3. |
- Goliath, Martin, et al.
(författare)
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Spatially self-similar spherically symmetric perfect-fluid models
- 1998
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Ingår i: Classical and quantum gravity. - : IOP Publishing. - 0264-9381 .- 1361-6382. ; 15:1, s. 167-186
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Tidskriftsartikel (refereegranskat)abstract
- Einstein's field equations for spatially self-similar spherically symmetric perfect-fluid models are investigated. The field equations are rewritten as a first-order system of autonomous differential equations. Dimensionless variables are chosen in such a way that the number of equations in the coupled system is reduced as far as possible and so that the reduced phase space becomes compact and regular. The system is subsequently analysed qualitatively with the theory of dynamical systems
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| 4. |
- Goliath, Martin, et al.
(författare)
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Timelike self-similar spherically symmetric perfect-fluid models
- 1998
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Ingår i: Classical and quantum gravity. - : IOP Publishing. - 0264-9381 .- 1361-6382. ; 15:9, s. 2841-2863
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Tidskriftsartikel (refereegranskat)abstract
- Einstein's field equations for timelike self-similar spherically symmetric perfect-fluid models are investigated. The field equations are rewritten as a first-order system of autonomous differential equations. Dimensionless variables are chosen in such a way that the number of equations in the coupled system is reduced as far as possible and so that the reduced phase space becomes compact and regular. The system is subsequently analysed qualitatively using the theory of dynamical systems
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| 5. |
- Grabowski, Martin, et al.
(författare)
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Sensorimotor performance and rotation correlate to lesion size in right but not left hemisphere brain infarcts in the spontaneously hypertensive rat
- 1991
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Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 547:2, s. 249-257
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Tidskriftsartikel (refereegranskat)abstract
- In order to correlate behavioural deficits to lesion size and to reveal possible functional asymmetries in the rat brain, locomotor activity, rotation and sensorimotor integration to touch were studied in spontaneously hypertensive rats (SHR) subjected to right or left middle cerebral artery occlusion. Control and infarcted rats showed no difference in locomotor activity. Infarcted rats tended to rotate towards the side of the lesion. A large sensorimotor deficit was found contralateral to the infarcted hemisphere. The absolute values of the side-biases for the rotation and sensorimotor tests were of the same degree irrespective of lesion side. Whereas the left hemisphere lesion size did not correlate to the behavioural outcome, the size of the right hemisphere lesion was highly correlated to the total sensorimotor deficit. Furthermore, the sensorimotor deficit of specific body parts was found to correlate to the damage of certain brain regions in a rostrocaudal fashion, reminiscent of a somatotopical organization. The extent of ipsilateral rotation correlated to brain tissue loss at the level of the posterior caudate-putamen. The present results indicate an asymmetrical organization for brain functions involved in the performance of the rotation and sensorimotor tests.
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| 6. |
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| 7. |
- Höst, Martin, et al.
(författare)
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A Subjective Effort Estimation Experiment
- 1997
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Ingår i: Information and Software Technology. - 0950-5849. ; 39:11, s. 755-762
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Effort estimation is difficult in general, and in software development it becomes even more complicated if the software process is changed. In this paper a number of alternative interview-based effort estimation methods is presented. The main focus of the paper is to present an experiment in which software engineers were asked to use different methods to estimate the actual effort it would take to perform a number of tasks. The result from the subjective data is compared with the actual outcome from performing the tasks.
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| 8. |
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| 9. |
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| 10. |
- Nilsson, Martin, et al.
(författare)
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Measurements of the Spatio-Temporal Polarization Characteristics of a Radio Channel at 1800 MHz
- 1999
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Ingår i: Proceedings IEEE Vehicular Technology Conference. - : IEEE. ; , s. 386-391
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Konferensbidrag (refereegranskat)abstract
- We present a combined measurement and analysis of the spatial, temporal, and polarisation characteristics of a 1800 MHz radio channel. The measurements were performed using a correlative channel sounder. A complex chirp signal with a bandwidth of 150 MHz was transmitted by a vertically polarized omnidirectional antenna and received by a 8+8 dual polarized planar antenna array. Measurements were taken at two different base station locations, one being suburban and the other urban. Using this data we characterize the radio channel in terms of azimuth and delay spread of the vertical and horizontal polarization.
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