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.

Photochemical Stability of Pentacene and a Substituted Pentacene in Solution and in Thin Films

Abstract: The organic semiconductor pentacene (1) has shown the highest field effect mobilities in thin films of any organic semiconductor, yet suffers from instability toward oxidation. 6,13-Bis(triisopropylsilylethynyl)pentacene (2) has been reported as an interesting functionalized pentacene which is soluble in common organic solvents and exhibits high carrier mobility (>0.1 cm2/Vs) in thin film transistor devices. In our investigations of 2, we were surprised by its remarkable stability in solution. Using UV−vis spectroscopy we observe that under ambient light conditions, 2 is approximately 50× more stable toward degradation in air-saturated tetrahydrofuran solution as compared to unsubstituted pentacene. Previous investigators have implicated oxygen in the mechanism of photodegradation of pentacene. In this study, quantum chemical calculations have been performed which demonstrate that alkynyl functionalization at the 6 and 13 positions reduces the rate of photooxidation in two ways. First, alkynyl substitutio...

Polynomial splines and their tensor products in extended linear modeling: 1994 Wald memorial lecture

Abstract: Analysis of variance type models are considered for a regression function or for the logarithm of a probability function, conditional probability function, density function, conditional density function, hazard function, conditional hazard function or spectral density function. Polynomial splines are used to model the main effects, and their tensor products are used to model any interaction components that are included. In the special context of survival analysis, the baseline hazard function is modeled and nonproportionality is allowed. In general, the theory involves the $L_2$ rate of convergence for the fitted model and its components. The methodology involves least squares and maximum likelihood estimation, stepwise addition of basis functions using Rao statistics, stepwise deletion using Wald statistics and model selection using the Bayesian information criterion, cross-validation or an independent test set. Publicly available software, written in C and interfaced to S/S-PLUS, is used to apply this methodology to real data.

Wireless data communication system having power saving function

Abstract: A wireless data communication system is operable in a power saving mode wherein stations are synchronized to be in an awake state to receive synchronizing messages (TIM, PSYNC) and traffic indicator information and are changed to a doze state if they are not to receive data messages. In one embodiment all stations ( 20 ) communicate via a base station access point ( 16 ), which broadcasts synchronizing messages (TIM) at regular intervals identifying stations ( 20 ) that are to receive data messages. In another embodiment all stations ( 220 ) communicate directly with one another, one station assumes the role of a master station and broadcasts synchronizing messages (PSYNC), and stations ( 220 ) desiring to transmit data messages transmit traffic indicator messages (PTIM) to the appropriate destination stations ( 220 ), in a synchronized awake period just before the next synchronizing message (PSYNC) is expected to arrive.

Gigabit rate packet pattern-matching using TCAM

Abstract: In today's Internet, worms and viruses cause service disruptions with enormous economic impact. Current attack prevention mechanisms rely on end-user cooperation to install new system patches or upgrade security software, yielding slow reaction time. However, malicious attacks spread much faster than users can respond, making effective attack prevention difficult network-based mechanisms, by avoiding end-user coordination, can respond rapidly to new attacks. Such mechanisms require the network to inspect the packet payload at line rates to detect and filter those packets containing worm signatures. These signature sets are large (e.g., thousands) and complex. Software-only implementations are unlikely to meet the performance goals. Therefore, making a network-based scheme practical requires efficient algorithms suitable for hardware implementations. This work develops a ternary content addressable memory (TCAM) based multiple-pattern matching scheme. The scheme can handle complex patterns; such as arbitrarily long patterns, correlated patterns, and patterns with negation. For the ClamAv virus database with 1768 patterns whose sizes vary from 6 bytes to 2189 bytes, the proposed scheme can operate at a 2 Gbps rate with a 240 KB TCAM.

Distributed telecommunications switching system and method

Abstract: A distributed telecommunications switching subsystem (100) receives and distributes data packets passed between a plurality of switching subsystems or channel banks (102, 104, 106) and a data packet switch (110). Each channel bank (102) has a stored list of addresses. When a channel bank (102) receives a data packet, it compares the address of the data packet to its stored list of addresses, and transmits the data packet to another channel bank (104) if the address of the data packet does not correspond to any of the addresses in its stored list of addresses. The data packet is passed on until it reaches a channel bank (106) with a matching address or else it is appropriately handled by a last channel bank (106) in the chain. If the address of data packet matches an address in its stored list of addresses, the channel bank (102) passes the data packet through a subscriber interface card (120) to a customer premises equipment unit (108) corresponding to the address of the data packet.