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Institution

Alcatel-Lucent

Stuttgart, Germany
About: Alcatel-Lucent is a based out in Stuttgart, Germany. It is known for research contribution in the topics: Signal & Network packet. The organization has 37003 authors who have published 53332 publications receiving 1430547 citations. The organization is also known as: Alcatel-Lucent S.A. & Alcatel.


Papers
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Journal ArticleDOI
19 Feb 2004
TL;DR: In this paper, the role of OPM as an enabling technology for advances in high-speed and optically switched networks is examined, with the focus on fault management and QoS monitoring in the optical domain.
Abstract: Progress in optical networking has stimulated interest in optical performance monitoring (OPM), particularly regarding signal quality measures such as optical signal-to-noise ratio (SNR), Q-factor, and dispersion. These advanced monitoring methods have the potential to extend fault management and quality-of-service (QoS) monitoring into the optical domain. This paper reviews OPM applications and techniques, while examining the role of OPM as an enabling technology for advances in high-speed and optically switched networks.

480 citations

Patent
Mooi Choo Chuah1
22 May 1998
TL;DR: In this article, the authors proposed a method for admitting new connections based on measured quantities in a wireless communications network having a base station and remote hosts, the base station measures and computes performance metrics to determine whether admission of the new connection could cause a failure to meet the Quality of Service (QoS) promised to already admitted connections.
Abstract: In a method for admitting new connections based on measured quantities in a wireless communications network having a base station and remote hosts, the base station measures and computes performance metrics to determine whether admission of the new connection could cause a failure to meet the Quality of Service (QoS) promised to already admitted connections. Only if the QoS can be maintained is the new connection is admitted. In one embodiment, the base station may optionally disconnect one or more already admitted lower priority connections if doing so will allow a higher priority new connection to be admitted without loss of QoS to the remaining already admitted connections. In one embodiment, each connection request specifies the average bit rate required and a traffic burstiness factor, the base station measures the number of bytes sent by each connection for a certain period of time and a burstiness factor for the traffic in either direction. The base station computes an equivalent number of admitted connections and determines whether the new equivalent number of admitted connections, after admission of the new connection, would exceed a threshold. The measured quantities can be various metrics related to interference. In one embodiment, uplink Frame Error Rate (FER), an average uplink bit rate, a burstiness factor of the uplink trafc, and a packet loss rate are measured at the base station. Downlink FER is similarly measured at each already admitted remote host and is sent to the base station. Alternatively, the average downlink bit rate, burstiness factor of downlink traffic, and packet loss rate may also be sent from each remote host to the base station. Considering the effect of the average rate and packet loss rate requested by a new connection and the computed equivalent bandwidth, the base station decides whether to admit the new connection based on whether the QoS of all admitted connections can be maintained.

478 citations

Journal ArticleDOI
02 Apr 1998-Nature
TL;DR: In this article, a different pattern of charge localization in the charge-ordered phase of the manganese oxide La1−xCaxMnO3 (x ⩾ 0.5) was reported.
Abstract: The propensity of systems of charge and spin to form, under certain conditions, ‘stripe’ phases has recently attracted much attention, as it has been suggested that dynamically fluctuating stripe phases may be of central importance for an understanding of the physics of high-temperature superconductors1,2,3,4,5. A related phenomenon — static charge stripes — characterizes6 the insulating antiferromagnetic ground state of the manganese oxides, a class of materials which (like the copper oxide superconductors) have a perovskite structure, and are notable for their extraordinary electronic and magnetic properties, such as colossal magnetoresistance and charge ordering7,8. Here we report a different pattern of charge localization in the charge-ordered phase of the manganese oxide La1−xCaxMnO3 (x ⩾ 0.5). This pattern takes the form of extremely stable pairs of Mn3+O6 stripes, with associated large lattice contractions (due to the Jahn–Teller effect), separated periodically by stripes of non-distorted Mn4+O6 octahedra. These periodicities, which adopt integer values between 2 and 5 times the lattice parameter of the orthorhombic unit cell, correspond to the commensurate carrier concentrations (x = 1/2, 2/3, 3/4 and 4/5): for other values of x, the pattern of charge ordering is a mixture of the two adjacent commensurate configurations. These paired Jahn–Teller stripes appear therefore to be the fundamental building blocks of the charge-ordered state in the manganese oxides, and so may be expected to have profound implications for the magnetic and transport properties of these materials.

474 citations

Journal ArticleDOI
TL;DR: The thermal properties of carbon nanotubes are directly related to their unique structure and small size, and they may prove to be an ideal material for the study of low-dimensional phonon physics, and for thermal management, both on the macro and the micro-scale as mentioned in this paper.
Abstract: The thermal properties of carbon nanotubes are directly related to their unique structure and small size. Because of these properties, nanotubes may prove to be an ideal material for the study of low-dimensional phonon physics, and for thermal management, both on the macro- and the micro-scale. We have begun to explore the thermal properties of nanotubes by measuring the specific heat and thermal conductivity of bulk SWNT samples. In addition, we have synthesized nanotube-based composite materials and measured their thermal conductivity. The measured specific heat of single-walled nanotubes differs from that of both 2D graphene and 3D graphite, especially at low temperatures, where 1D quantization of the phonon bandstructure is observed. The measured specific heat shows only weak effects of intertube coupling in nanotube bundling, suggesting that this coupling is weaker than expected. The thermal conductivity of nanotubes is large, even in bulk samples: aligned bundles of SWNTs show a thermal conductivity of >200 W/m K at room temperature. A linear K(T) up to approximately 40 K may be due to 1D quantization; measurement of K(T) of samples with different average nanotube diameters supports this interpretation. Nanotube–epoxy blends show significantly enhanced thermal conductivity, showing that nanotube-based composites may be useful not only for their potentially high strength, but also for their potentially high thermal conductivity.

474 citations

Proceedings ArticleDOI
21 Mar 1999
TL;DR: It is argued that the placement of web proxy is critical to the performance and the optimal placement policy of web proxies for a target web server in the Internet is investigated and this can be modeled a dynamic programming problem.
Abstract: Web caching or web proxy has been considered as the prime vehicle of coping with the ever-increasing demand for information retrieval over the Internet, the WWW being a typical example. Existing work on web proxy has primarily focused on content based caching; relatively less attention has been given to the development of proper placement strategies for the potential web proxies in the Internet. In this paper, we argue that the placement of web proxies is critical to the performance and further investigates the optimal placement policy of web proxies for a target web server in the Internet. The objective is to optimize a given performance measure for the target web server subject to system resources and traffic pattern. Specifically, we are interested in finding the optimal placement of multiple web proxies (M) among potential sites (N) under a given traffic pattern. We show this can be modeled a dynamic programming problem. We further obtain the optimal solution for the tree topology using O(N/sup 3/M/sup 2/) time.

471 citations


Authors

Showing all 37011 results

NameH-indexPapersCitations
George M. Whitesides2401739269833
Yoshua Bengio2021033420313
John A. Rogers1771341127390
Zhenan Bao169865106571
Thomas S. Huang1461299101564
Federico Capasso134118976957
Robert S. Brown130124365822
Christos Faloutsos12778977746
Robert J. Cava125104271819
Ramamoorthy Ramesh12264967418
Yann LeCun121369171211
Kamil Ugurbil12053659053
Don Towsley11988356671
Steven P. DenBaars118136660343
Robert E. Tarjan11440067305
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202212
202130
202050
201983
2018215