Alcatel-Lucent

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.

High ε gate dielectrics Gd2O3 and Y2O3 for silicon

Abstract: We report on growth and characterization of both epitaxial and amorphous films Gd2O3 of (e=14) and Y2O3(e=18) as the gate dielectrics for Si prepared by ultrahigh vacuum vapor deposition. The use of vicinal Si (100) substrates is key to the growth of (110) oriented, single-domain films in the Mn2O3 structure. Typical electrical leakage results are 10−3 A/cm2 at 1 V for single domain epitaxial Gd2O3 and Y2O3 films with an equivalent SiO2 thickness, teq of 15 A, and 10−6 A/cm2 at 1 V for smooth amorphous Y2O3 films (e=18) with a teq of only 10 A. For all the Gd2O3 films, the absence of SiO2 segregation at the interface is established from infrared absorption measurements.

A Bose-Einstein condensate in an optical lattice

Abstract: We have performed a number of experiments with a Bose-Einstein condensate (BEC) in a one-dimensional optical lattice. Making use of the small momentum spread of a BEC and standard atom optics techniques, a high level of coherent control over an artificial solid-state system is demonstrated. We are able to load the BEC into the lattice ground state with a very high efficiency by adiabatically turning on the optical lattice. We coherently transfer population between lattice states and observe their evolution. Methods are developed and used to perform band spectroscopy. We use these techniques to build a BEC accelerator and a novel, coherent, large-momentum-transfer beam-splitter.

Optimal placement of training for frequency-selective block-fading channels

Abstract: The problem of placing training symbols optimally for orthogonal frequency-division multiplexing (OFDM) and single-carrier systems is considered. The channel is assumed to be quasi-static with a finite impulse response of length (L + 1) samples. Under the assumptions that neither the transmitter nor the receiver knows the channel, and that the receiver forms a minimum mean square error (MMSE) channel estimate based on training symbols only, training is optimized by maximizing a tight lower bound on the ergodic training-based independent and identically distributed (i.i.d.) capacity. For OFDM systems, it is shown that the lower bound is maximized by placing the known symbols periodically in frequency. For single-carrier systems, under the assumption that the training symbols are placed in clusters of length /spl alpha/ /spl ges/ (2L + 1), it is shown that the lower bound is maximized by a family of placement schemes called QPP-/spl alpha/, where QPP stands for quasi-periodic placement. These placement schemes are formed by grouping the known symbols into as many clusters as possible and then placing these clusters periodically in the packet. For both OFDM and single-carrier systems, the optimum energy tradeoff between training and data is also obtained.

Model Checking of Message Sequence Charts

Abstract: Scenario-based specifications such as message sequence charts (MSC) offer an intuitive and visual way of describing design requirements Such specifications focus on message exchanges among communicating entities in distributed software systems Structured specifications such as MSC-graphs and Hierarchical MSC-graphs (HMSC) allow convenient expression of multiple scenarios, and can be viewed as an early model of the system In this paper, we present a comprehensive study of the problem of verifying whether this model satisfies a temporal requirement given by an automaton, by developing algorithms for the different cases along with matching lower bounds When the model is given as an MSC, model checking can be done by constructing a suitable automaton for the linearizations of the partial order specified by the MSC, and the problem is coNP-complete When the model is given by an MSC-graph, we consider two possible semantics depending on the synchronous or asynchronous interpretation of concatenating two MSCs For synchronous model checking of MSC-graphs and HMSCs, we present algorithms whose time complexity is proportional to the product of the size of the description and the cost of processing MSCs at individual vertices Under the asynchronous interpretation, we prove undecidability of the model checking problem We, then, identify a natural requirement of boundedness, give algorithms to check boundedness, and establish asynchronous model checking to be Pspace-complete for bounded MSC-graphs and Expspace-complete for bounded HMSCs