| 1. |
- Ozolins, Oskars, et al.
(författare)
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7×149 Gbit/s PAM4 transmission over 1 km multicore fiber for short-reach optical interconnects
- 2018
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Ingår i: Optics InfoBase Conference Papers. - : Optics Info Base, Optical Society of America. - 9781557528209
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Konferensbidrag (refereegranskat)abstract
- We transmit 80 Gbaud/λ/core PAM4 signal enabled by 1.55 μm EML over 1 km 7-core fiber. The solution achieves single-wavelength and single-fiber 1.04 Tbit/s post-FEC transmission enhancing bandwidth-density for short-reach optical interconnects.
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| 2. |
- van der Velde, Y., et al.
(författare)
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Improving catchment discharge predictions by inferring flow route contributions from a nested-scale monitoring and model setup
- 2011
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Ingår i: Hydrology and Earth System Sciences. - : Copernicus GmbH. - 1027-5606 .- 1607-7938. ; 15, s. 913-930
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Tidskriftsartikel (refereegranskat)abstract
- Identifying effective measures to reduce nutrient loads of headwaters in lowland catchments requires a thorough understanding of flow routes of water and nutrients. In this paper we assess the value of nested-scale discharge and groundwater level measurements for the estimation of flow route volumes and for predictions of catchment discharge. In order to relate field-site measurements to the catchment-scale an upscaling approach is introduced that assumes that scale differences in flow route fluxes originate from differences in the relationship between groundwater storage and the spatial structure of the groundwater table. This relationship is characterized by the Groundwater Depth Distribution (GDD) curve that relates spatial variation in groundwater depths to the average groundwater depth. The GDD-curve was measured for a single field site (0.009 km(2)) and simple process descriptions were applied to relate groundwater levels to flow route discharges. This parsimonious model could accurately describe observed storage, tube drain discharge, overland flow and groundwater flow simultaneously with Nash-Sutcliff coefficients exceeding 0.8. A probabilistic Monte Carlo approach was applied to upscale field-site measurements to catchment scales by inferring scale-specific GDD-curves from the hydrographs of two nested catchments (0.4 and 6.5 km(2)). The estimated contribution of tube drain effluent (a dominant source for nitrates) decreased with increasing scale from 76-79% at the field-site to 34-61% and 25-50% for both catchment scales. These results were validated by demonstrating that a model conditioned on nested-scale measurements improves simulations of nitrate loads and predictions of extreme discharges during validation periods compared to a model that was conditioned on catchment discharge only.
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| 3. |
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| 4. |
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| 5. |
- van der Velde, Y., et al.
(författare)
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Catchment-scale non-linear groundwater-surface water interactions in densely drained lowland catchments
- 2009
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Ingår i: Hydrology and Earth System Sciences. - 1027-5606 .- 1607-7938. ; 13, s. 1867-1885
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Tidskriftsartikel (refereegranskat)abstract
- Freely discharging lowland catchments are characterized by a strongly seasonal contracting and expanding system of discharging streams and ditches. Due to this rapidly changing active channel network, discharge and solute transport cannot be modeled by a single characteristic travel path, travel time distribution, unit hydrograph, or linear reservoir. We propose a systematic spatial averaging approach to derive catchment-scale storage and discharge from point-scale water balances. The effects of spatial heterogeneity in soil properties, vegetation, and drainage network are lumped and described by a relation between groundwater storage and the spatial probability distribution of groundwater depths with measurable parameters. The model describes how, in lowland catchments, the catchment-scale flux from groundwater to surface water via various flow routes is affected by a changing active channel network, the unsaturated zone and surface ponding. We used observations of groundwater levels and catchment discharge of a 6.6 km(2) Dutch watershed in combination with a high-resolution spatially distributed hydrological model to test the model approach. Good results were obtained when modeling hourly discharges for a period of eight years. The validity of the underlying assumptions still needs to be tested under different conditions and for catchments of various sizes. Nevertheless, at this stage the model can already improve monitoring efficiency of groundwater-surface water interactions.
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| 6. |
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| 7. |
- Yin, X., et al.
(författare)
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Towards efficient 100 Gb/s serial rate optical interconnects : A duobinary way
- 2017
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Ingår i: 6th IEEE Photonics Society Optical Interconnects Conference, OI 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509050154 ; , s. 33-34
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Konferensbidrag (refereegranskat)abstract
- Recent advances in integrated opto-electronic devices and front end circuits have made it possible to efficiently transmit very high data rates over optical links for HPC/datacenter applications. This paper reviews our current progress towards serial 100-Gb/s optical interconnects, with emphasis on electrical duobinary (EDB) modulation.
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