The Experts below are selected from a list of 23754 Experts worldwide ranked by ideXlab platform
Gerry Weinmaster - One of the best experts on this subject based on the ideXlab platform.
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The divergent DSL ligand Dll3 does not activate Notch signaling but cell autonomously attenuates signaling induced by other DSL ligands.
Journal of Cell Biology, 2005Co-Authors: Ena Ladi, Chris Kintner, James T. Nichols, Alison Miyamoto, Christine Yao, Liang-tung Yang, Jim Boulter, Yi E. Sun, Gerry WeinmasterAbstract:Mutations in the DSL (Delta, Serrate, Lag2) Notch (N) ligand Delta-like (Dll) 3 cause skeletal abnormalities in spondylocostal dysostosis, which is consistent with a critical role for N signaling during somitogenesis. Understanding how Dll3 functions is complicated by reports that DSL ligands both activate and inhibit N signaling. In contrast to other DSL ligands, we show that Dll3 does not activate N signaling in multiple assays. Consistent with these findings, Dll3 does not bind to cells expressing any of the four N receptors, and N1 does not bind Dll3-expressing cells. However, in a cell-autonomous manner, Dll3 suppressed N signaling, as was found for other DSL ligands. Therefore, Dll3 functions not as an activator as previously reported but rather as a dedicated inhibitor of N signaling. As an N antagonist, Dll3 promoted Xenopus laevis neurogenesis and inhibited glial differentiation of mouse neural progenitors. Finally, together with the modulator lunatic fringe, Dll3 altered N signaling levels that were induced by other DSL ligands.
Mehdi Mohseni - One of the best experts on this subject based on the ideXlab platform.
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gigabit DSL
IEEE Transactions on Communications, 2007Co-Authors: Bin Lee, J M Cioffi, S Jagannathan, Mehdi MohseniAbstract:This paper applies multiple-input multiple-output (MIMO) transmission methods to multiwire communication systems. Using channel matrices generated from a binder MIMO channel model, a performance assessment of digital subscriber line (DSL) technology based on MIMO transmission methods finds that symmetric data rates of more than 1 Gbps are achievable over four twisted pairs (category 3) for a 300 m range. Similar results are also obtained for a ldquoquadrdquo cable. To achieve this data rate, this paper proposes that the source and load be excited using common mode.
John M. Cioffi - One of the best experts on this subject based on the ideXlab platform.
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Greening the copper access network with dynamic spectrum management
International Journal of Autonomous and Adaptive Communications Systems, 2010Co-Authors: John M. Cioffi, Aakanksha Chowdhery, Sarangapani JagannathanAbstract:This paper investigates the benefits of dynamic spectrum management (DSM) in terms of reducing the power consumption and improving the data rates and robustness in digital subscriber line (DSL) networks. Non-DSM solutions cause strong interference in a shared DSL binder and lead to instability in the network. However, DSM mitigates such interference, stabilises DSL service, and saves power consumed by the DSL networks. This paper compares the savings in power and the improvement in data rates and robustness of the DSL networks when the proposed DSM methods are used instead of other non-DSM techniques. The power savings, data rate increase and quality-of-service improvement by DSM make the operation of DSL networks greener and more efficient, which in turn reduces operational expenditure and brings higher customer satisfaction for DSL service providers.
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Dynamic spectrum management for next-generation DSL systems
IEEE Communications Magazine, 2002Co-Authors: Kee Bong Song, Seong Taek Chung, Georgios Ginis, John M. CioffiAbstract:The performance of DSL systems is severely constrained by crosstalk due to the electromagnetic coupling among the multiple twisted pairs making up a phone cable. In order to reduce performance loss arising from crosstalk, DSL systems are currently designed under the assumption of worst-case crosstalk scenarios leading to overly conservative DSL deployments. This article presents a new paradigm for DSL system design, which takes into account the multi-user aspects of the DSL transmission environment. Dynamic spectrum management (DSM) departs from the current design philosophy by enabling transceivers to autonomously and dynamically optimize their communication settings with respect to both the channel and the transmissions of neighboring systems. Along with this distributed optimization, when an additional degree of coordination becomes available for future DSL deployment, DSM will allow even greater improvement in DSL performance. Implementations are readily applicable without causing any performance degradation to the existing DSLs under static spectrum management. After providing an overview of the DSM concept, this article reviews two practical DSM methods: iterative water-filling, an autonomous distributed power control method enabling great improvement in performance, which can be implemented through software options in some existing ADSL and VDSL systems; and vectored-DMT, a coordinated transmission/reception technique achieving crosstalk-free communication for DSL systems, which brings within reach the dream of providing universal Internet access at speeds close to 100 Mb/s to 500 m on 1-2 lines and beyond 1 km on 2-4 lines. DSM-capable DSL thus enables the broadband age.
Marc Moonen - One of the best experts on this subject based on the ideXlab platform.
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distributed spectrum management algorithms for multiuser DSL networks
IEEE Transactions on Signal Processing, 2008Co-Authors: Paschalis Tsiaflakis, Moritz Diehl, Marc MoonenAbstract:Modern digital subscriber line (DSL) networks suffer from crosstalk among different lines in the same cable bundle. This crosstalk can lead to a major performance degradation. By balancing the transmit power spectra, the impact of crosstalk can be minimized leading to spectacular performance gains. This is referred to as spectrum management. In this paper, a unifying perspective is presented on distributed spectrum management algorithms based on the Karush-Kuhn-Tucker (KKT) conditions. Furthermore, novel distributed algorithms are presented within the same KKT framework. The proposed distributed algorithms consist of local water-filling-like algorithms running in the individual modems, controlled by the spectrum management center. Extensive simulation results show that the proposed algorithms perform very well for several multi-user ADSL and VDSL scenarios.
Ena Ladi - One of the best experts on this subject based on the ideXlab platform.
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The divergent DSL ligand Dll3 does not activate Notch signaling but cell autonomously attenuates signaling induced by other DSL ligands.
Journal of Cell Biology, 2005Co-Authors: Ena Ladi, Chris Kintner, James T. Nichols, Alison Miyamoto, Christine Yao, Liang-tung Yang, Jim Boulter, Yi E. Sun, Gerry WeinmasterAbstract:Mutations in the DSL (Delta, Serrate, Lag2) Notch (N) ligand Delta-like (Dll) 3 cause skeletal abnormalities in spondylocostal dysostosis, which is consistent with a critical role for N signaling during somitogenesis. Understanding how Dll3 functions is complicated by reports that DSL ligands both activate and inhibit N signaling. In contrast to other DSL ligands, we show that Dll3 does not activate N signaling in multiple assays. Consistent with these findings, Dll3 does not bind to cells expressing any of the four N receptors, and N1 does not bind Dll3-expressing cells. However, in a cell-autonomous manner, Dll3 suppressed N signaling, as was found for other DSL ligands. Therefore, Dll3 functions not as an activator as previously reported but rather as a dedicated inhibitor of N signaling. As an N antagonist, Dll3 promoted Xenopus laevis neurogenesis and inhibited glial differentiation of mouse neural progenitors. Finally, together with the modulator lunatic fringe, Dll3 altered N signaling levels that were induced by other DSL ligands.
