| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Olsson, Samuel L I, 1984, et al.
(författare)
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Phase-Sensitive Amplified Transmission Links for Improved Sensitivity and Nonlinearity Tolerance
- 2015
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Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 33:3, s. 710-721
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we investigate the properties of transmission links amplified by phase-sensitive amplifiers (PSAs). Using an analytic description we explain the principles enabling improved sensitivity compared to conventional links amplified by phase-insensitive amplifiers (PIAs) and mitigation of nonlinear transmission distortions. We demonstrate these features using numerical simulations and in particular we show the possibility of efficiently mitigating both self-phase modulation (SPM) induced distortions and nonlinear phase noise (NLPN) if the link dispersion map is optimized. The properties of the noise on signal and idler are important and to enable NLPN mitigation the noise must be correlated at the link input. We investigate the role of the dispersion map in detail and show that in a link with standard single mode fiber (SSMF) the optimum dispersion map for efficient nonlinearity mitigation corresponds to pre-compensation of an amount equal to the effective loss length. Furthermore, we experimentally demonstrate both improved sensitivity and mitigation of nonlinearities in a 105 km PSA-amplified link transmitting 10 GBd 16-ary quadrature amplitude modulation (16QAM) data. We measure a combined effect allowing for more than 12 dB larger span loss in a PSA-amplified link compared to a conventional PIA-amplified link to reach the same bit error ratio (BER) of 1×10-3.
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| 3. |
- Axin, Mikael, 1984-, et al.
(författare)
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Next Generation Simulation Software using Transmission Line Elements
- 2010
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Ingår i: Fluid Power and Motion Control. - : Centre for Power Transmission and Motion Control. - 9781861971814 ; , s. 265-276
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Konferensbidrag (refereegranskat)abstract
- A suitable method for simulating large complex dynamic systems is represented by distributed modelling using transmission line elements. The method is applicable to all physical systems, such as mechanical, electrical and pneumatics, but is particularly well suited to simulate systems where wave propagation is an important issue, for instance hydraulic systems. By using this method, components can be numerically isolated from each other, which provide highly robust numerical properties. It also enables the use of multi-core architecture since a system model can be composed by distributed simulations of subsystems on different processor cores.Technologies based on transmission lines has successfully been implemented in the HOPSAN simulation package, develop at Linköping University. Currently, the next generation of HOPSAN is developed using an object-oriented approach. The work is focused on compatibility, execution speed and real-time simulation in order to facilitate hardware-in-the-loop applications. This paper presents the work progress and some possible features in the new version of the HOPSAN simulation package.
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| 4. |
- Bachmann, Bernhard, et al.
(författare)
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Parallel Multiple-Shooting and Collocation Optimization with OpenModelica
- 2012
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Ingår i: Proceedings of the 9th International MODELICA Conference; September 3-5; 2012; Munich; Germany. - : Linköping University Electronic Press. - 9789175198262 ; , s. 659-668
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Konferensbidrag (refereegranskat)abstract
- Nonlinear model predictive control (NMPC) has become increasingly important for today’s control engineers during the last decade. In order to apply NMPC a nonlinear optimal control problem (NOCP) must be solved which needs a high computational effort.State-of-the-art solution algorithms are based on multiple shooting or collocation algorithms; which are required to solve the underlying dynamic model formulation. This paper describes a general discretization scheme applied to the dynamic model description which can be further concretized to reproduce the mul-tiple shooting or collocation approach. Furthermore; this approach can be refined to represent a total collocation method in order to solve the underlying NOCP much more efficiently. Further speedup of optimization has been achieved by parallelizing the calculation of model specific parts (e.g. constraints; Jacobians; etc.) and is presented in the coming sections.The corresponding discretized optimization problem has been solved by the interior optimizer Ipopt. The proposed parallelized algorithms have been tested on different applications. As industrial relevant application an optimal control of a Diesel-Electric power train has been investigated. The modeling and problem description has been done in Optimica and Modelica. The simulation has been performed using OpenModelica. Speedup curves for parallel execution are presented.
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| 5. |
- Ellis, Hanna, et al.
(författare)
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Linker Unit Modification of Triphenylamine-Based Organic Dyes for Efficient Cobalt Mediated Dye-Sensitized Solar Cells
- 2013
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:41, s. 21029-21036
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Tidskriftsartikel (refereegranskat)abstract
- Linker unit modification of donor-linker-acceptor-based organic dyes was investigated with respect to the spectral and physicochemical properties of the dyes. The spectral response for a series of triphenylamine (TPA)-based organic dyes, called LEG1-4, was shifted into the red wavelength region, and the extinction coefficient of the dyes was increased by introducing different substituted dithiophene units on the pi-conjugated linker. The photovoltaic performance of dye-sensitized solar cells (DSCs) incorporating the different dyes in combination with cobalt-based electrolytes was found to be dependent on dye binding. The binding morphology of the dyes on the TiO2 was studied using photoelectron spectroscopy, which demonstrated that the introduction of alkyl chains and different substituents on the dithiophene linker unit resulted in a larger tilt angle of the dyes with respect to the normal of the TiO2-surface, and thereby a lower surface coverage. The good photovoltaic performance for cobalt electrolyte-based DSCs found here and by other groups using TPA-based organic dyes with a cyclopentadithiophene linker unit substituted with alkyl chains was mainly attributed to the extended spectral response of the dye, whereas the larger tilt angle of the dye with respect to the TiO2-surface resulted in less efficient packing of the dye molecules and enhanced recombination between electrons in TiO2 and Co(III) species in the electrolyte.
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| 6. |
- Eriksson, Klas, 1983, et al.
(författare)
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InP DHBT Amplifier Modules Operating Between 150 and 300 GHz Using Membrane Technology
- 2015
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 63:2, s. 433-440
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present WR05 (140-220 GHz) and WR03 (220-325 GHz) five-stage amplifier modules with novel membrane microstrip-to-waveguide transitions. The modules use a 250-nm InP double heterojunction bipolar transistor (DHBT) technology and multilayer thin-film microstrip transmission lines. The waveguide transitions use E-plane probes on 3- μm-thin GaAs membrane substrate. Beam lead connectors integrated on the transition eliminate the need of highly reactive bond wires. In addition, process steps such as backside metallization, backside vias, and nonrectangular dicing of the integrated circuits (ICs) are not required. The WR05 amplifier module demonstrates a peak gain of 24 dB at 245 GHz and more than 10-dB gain from 155 to 270 GHz. The WR-03 module has 19-dB gain from 230 to 254 GHz with input and output return loss better than 10 dB from 225 to 330 GHz. The two modules were also characterized in terms of noise. The minimum noise figures were measured to 9.7 dB at 195 GHz and 10.8 dB at 240 GHz for the WR05 and WR03 modules, respectively. To the authors' best knowledge, these are the first published results on an InP DHBT amplifier modules operating at these high frequencies. It is also the first time that membrane technology is used for IC packaging, regardless of IC technology.
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| 7. |
- Eriksson, Tobias, 1986, et al.
(författare)
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625 Gbit/s Superchannel Consisting of Interleaved DP-16QAM and DP-QPSK with 4.17 bit/s/Hz Spectral Efficiency
- 2012
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Ingår i: European Conference on Optical Communications (ECOC), Amsterdam, The Netherlands, paper P4.11.
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Konferensbidrag (refereegranskat)abstract
- Abstract (40-Word Limit): We experimentally investigated a superchannel consisting of 25 GHz spaced interleaved 3x18.67 GBaud DP-QPSK and 3x18.67 GBaud DP-16QAM. We showed a 0.3 dB improvement in the Q-value averaged over the center two channels compared to an all DP-16QAM superchannel with the same SE after transmission over 480 km and 560 km of SSMF.
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| 8. |
- Eriksson, Tobias, 1986, et al.
(författare)
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Comparison of 128-SP-QAM and PM-16QAM in long-haul WDM transmission
- 2013
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Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 21:16, s. 19269-19279
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Tidskriftsartikel (refereegranskat)abstract
- We investigate 128-level set-partitioning quadrature amplitude modulation (128-SP-QAM) experimentally and compare the performance to polarization-multiplexed 16QAM both at the same bit rate and at the same symbol rate. Using a recirculating loop we study both single channel and wavelength-division multiplexing (WDM) transmission and demonstrate a reach of up to 2680 km at a bit-error rate of 10−3 for 128-SP-QAM. We confirm that 128-SP-QAM has an increased sensitivity compared to PM-16QAM and show that the maximum transmission distance can be increased by more than 50 % at the same bit rate for both single channel and WDM transmission. We also investigate the performance at the same symbol rate as a possible fall back solution in a degrading link.
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| 9. |
- Eriksson, Tobias, 1986, et al.
(författare)
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Experimental Demonstration of 128-SP-QAM in Uncompensated Long-Haul Transmission
- 2013
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Ingår i: 2012 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013, Anaheim, 17-21 March 2013. - 9781479904570 ; , s. OTu3B.2-
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Konferensbidrag (refereegranskat)abstract
- We demonstrate 128-SP-QAM experimentally for the first time and compare the performance to PM-16QAM at the same symbol rate (10.5 Gbaud). We find a 1.7 dB increased sensitivity and 50% increased transmission reach over PM-16QAM.
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| 10. |
- Eriksson, Tobias, 1986, et al.
(författare)
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Frequency and polarization switched QPSK
- 2013
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Ingår i: 39th European Conference and Exhibition on Optical Communication, ECOC 2013; London; United Kingdom; 22 September 2013 through 26 September 2013. - : Institution of Engineering and Technology. - 9781849197595 ; 2013:622 CP, s. 816-818
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Konferensbidrag (refereegranskat)abstract
- We propose 8-dimensional biorthogonal modulation as a format with 3 dB increased asymptotic power efficiency over PM-QPSK. We demonstrate one possible experimental implementation of this format based on frequency and polarization switching and compare with dual-carrier PM-QPSK and PS-QPSK.
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