| 1. |
- Acatauassu, Diogo, et al.
(författare)
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Simple and Causal Copper Cable Model Suitable for G.fast Frequencies
- 2014
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Ingår i: IEEE Transactions on Communications. - 0090-6778. ; 62:11, s. 4040-4051
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Tidskriftsartikel (refereegranskat)abstract
- G.fast is a new standard from the International Telecommunication Union, which targets 1 Gb/s over short copper loops using frequencies up to 212 MHz. This new technology requires accurate parametric cable models for simulation, design, and performance evaluation tests. Some existing copper cable models were designed for the very high speed digital subscriber line spectra, i.e., frequencies up to 30 MHz, and adopt assumptions that are violated when the frequency range is extended to G.fast frequencies. This paper introduces a simple and causal cable model that is able to accurately characterize copper loops composed by single or multiple segments, in both frequency and time domains. Results using G.fast topologies show that, apart from being accurate, the new model is attractive due to its low computational cost and closed-form expressions for fitting its parameters to measurement data.
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| 2. |
- Bentley, Michael J., et al.
(författare)
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A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 100, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets and recent decades have seen an upsurge in such data gathering around the continent and Sub-Antarctic islands. Here, we report a new synthesis of those datasets, based on an accompanying series of reviews of the geological data, organised by sector. We present a series of timeslice maps for 20 ka, 15 ka, 10 ka and 5 ka, including grounding line position and ice sheet thickness changes, along with a clear assessment of levels of confidence. The reconstruction shows that the Antarctic Ice sheet did not everywhere reach the continental shelf edge at its maximum, that initial retreat was asynchronous, and that the spatial pattern of deglaciation was highly variable, particularly on the inner shelf. The deglacial reconstruction is consistent with a moderate overall excess ice volume and with a relatively small Antarctic contribution to meltwater pulse la. We discuss key areas of uncertainty both around the continent and by time interval, and we highlight potential priorities for future work. The synthesis is intended to be a resource for the modelling and glacial geological community.
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| 3. |
- Höst, Stefan, et al.
(författare)
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Low complexity computation of the BT0 Hilbert twisted pair cable model
- 2010
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Ingår i: [Host publication title missing]. ; , s. 195-199
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Konferensbidrag (refereegranskat)abstract
- By use of the Hilbert transform the standardized BT0 twisted pair cable model can be rederived as a causal model with lower order, denoted BT0$_H$. In the present contribution the computational complexity of the BT0$_H$ model is decreased as the Hilbert transform is approximated with a look-up table implemented as a polynomial approximation. This results in a model of lower complexity than BT0$_H$ and lower order than the original BT0 model. Finally a comparison on causality of the considered models is presented.
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