Showing papers by "Orange S.A. published in 2003"

Electron beam lithography in nanoscale fabrication: recent development

Abstract: Miniaturization is the central theme in modern fabrication technology. Many of the components used in modern products are getting smaller and smaller. In this paper, the recent development of the electron beam lithography technique is reviewed with an emphasis on fabricating devices at the nanometer scale. Because of its very short wavelength and reasonable energy density characteristics, e-beam lithography has the ability to fabricate patterns having nanometer feature sizes. As a result, many nanoscale devices have been successfully fabricated by this technique. Following an introduction of this technique, recent developments in processing, tooling, resist, and pattern controlling are separately examined and discussed. Examples of nanodevices made by several different e-beam lithographic schemes are given, to illustrate the versatility and advancement of the e-beam lithography technique. Finally, future trends in this technique are discussed.

Wireless downlink data channels: user performance and cell dimensioning

Abstract: We consider wireless downlink data channels where the transmission power of each base station is time-shared between a dynamic number of active users as in CDMA/HDR systems. We derive analytical results relating user performance, in terms of blocking probability and data throughput, to cell size and traffic density. These results are used to address a number of practically interesting issues, including the trade-off between cell coverage and cell capacity and the choice of efficient scheduling and admission control schemes.

Insensitive Bandwidth Sharing in Data Networks

Abstract: We represent a data network as a set of links shared by a dynamic number of competing flows. These flows are generated within sessions and correspond to the transfer of a random volume of data on a pre-defined network route. The evolution of the stochastic process describing the number of flows on all routes, which determines the performance of the data transfers, depends on how link capacity is allocated between competing flows. We use some key properties of Whittle queueing networks to characterize the class of allocations which are insensitive in the sense that the stationary distribution of this stochastic process does not depend on any traffic characteristics (session structure, data volume distribution) except the traffic intensity on each route. We show in particular that this insensitivity property does not hold in general for well-known allocations such as max-min fairness or proportional fairness. These results are ilustrated by several examples on a number of network topologies.

Security Analysis of SHA-256 and Sisters

Abstract: This paper studies the security of SHA-256, SHA-384 and SHA-512 against collision attacks and provides some insight into the security properties of the basic building blocks of the structure. It is concluded that neither Chabaud and Joux’s attack, nor Dobbertin-style attacks apply. Differential and linear attacks also don’t apply on the underlying structure. However we show that slightly simplified versions of the hash functions are surprisingly weak : whenever symmetric constants and initialization values are used throughout the computations, and modular additions are replaced by exclusive or operations, symmetric messages hash to symmetric digests. Therefore the complexity of collision search on these modified hash functions potentially becomes as low as one wishes.

Pilot-aided channel estimation for OFDM/OQAM

Abstract: OFDM/offsetQAM is an interesting alternative to classical OFDM modulation, as it does not require the use of guard interval. This characteristic makes its spectral efficiency optimal. On the other hand, this modulation is less robust to Rayleigh fading channel. Indeed, when classical channel estimation used for OFDM modulation is applied straightforwardly to OFDM/OQAM modulation, an intrinsic inter-symbol-interference is observed. This deeply degrades its performances. In this paper, we theoretically explain this phenomenon and propose a reliable method to significantly reduce it. Results of different methods of pilot-aided channel estimation over delay-Doppler channels are shown in this paper.

Text language identification

Abstract: After prestoring first character strings that occur frequently in words of languages and second character strings that are a typical therein, a device for automatically identifying the language of a text from a plurality of languages extracts words from the text and constructs all of the character strings contained in each extracted word. Each string in an extracted word is compared to the first and second strings of a particular language. If the word contains a first string, a score of the language is increased by a coefficient depending in particular on the position of the first string in the word. If the word contains a second string, the score is decreased by a coefficient associated with the second string. The highest of the scores corresponding to the predetermined languages identifies the language of the text.

Correlation of Intrusion Symptoms: An Application of Chronicles

Abstract: In this paper, we propose a multi-alarm misuse correlation component based on the chronicles formalism. Chronicles provide a high level declarative language and a recognition system that is used in other areas where dynamic systems are monitored. This formalism allows us to reduce the number of alarms shipped to the operator and enhances the quality of the diagnosis provided.

A new robot architecture for tele-echography

Abstract: This paper presents a slave robot carrying an ultrasound probe for remote echographic examination. This robot is integrated in a master-slave system called robotic tele-echography (TER). The system allows an expert operator to perform a remote diagnosis from echographic data he acquires on a patient located in a distant place. The originality of this robot lies in its architecture: the cable-driven robot is lightweight and semirigid, and it is positioned on the patient body. In this paper, we describe the clinical application, the system architecture, the second implementation of the robot, and experiments performed with this prototype.

Wireless system having a dynamically configured multimodal user interface based on user preferences

Abstract: A wireless system is provided for dynamically configuring a multimodal user interface based on user preferences to communicate with a local appliance. An appliance node is operably linked to the local appliance and configured to transmit interface format data of the local appliance for reception by the portable terminal when in the transmit vicinity of the appliance node. The portable terminal transmits an interface request therefrom in response to the reception of the interface format data. A server node is configured to receive the interface request from the portable terminal for identifying a user interface for use in interacting with the appliance. The server node transmits the identified user interface or the information for generating user interface to the portable terminal and the portable terminal presents the user interface or generates the user interface based on provided information to a user via a display of the portable terminal wherein the user may interact with the appliance in accordance with the identified user interface.

System, method, device, and computer program product for a sender to send a personalized notification to a recipient of a communication

Abstract: In a communication network, a caller selects a personalized notification to be sent together with his call. The personalized notification, for example a personalized ringtone, is sent as a message together with the call. The switching center sends the message to the recipient of the call when the call is routed. The recipient's device determines that the incoming caller matches the sender of the message, and the message is opened, causing the caller's personalized notification to be played on the recipient's device.

System for consulting and/or updating dns servers and/or ldap directories

Abstract: A database in a system for consulting and/or updating one or more resource records, is stored by a domain name server, (DNS server), or a directory server, (the LDAP server), indirectly accessed from a DNS server. A communication arrangement enables the system to receive from a telecommunication terminal a request for consultation and/or modification of the record or a programming of such a request. A controller determines, from the consultation and/or modification request transmitted to the system or previously programmed in the system, a domain name and an operation to be performed on the record. A protocol manager searches, from the domain name, the IP address of the server storing the database and, according to the operation, transmits to the server a request to read or update the record.

On fair e-cash systems based on group signature schemes

Abstract: A fair electronic cash system is a system that allows customers to make payments anonymously Moreover, under certain circumstances, a trusted authority can revoke the anonymity of suspicious transactions Various fair e-cash systems using group signature schemes have been proposed [4,15,16,18] Unfortunately, they do not realize coin tracing [4,15,18] (the possibility to trace the coins withdrawn by a customer) In this paper, we describe several failures in the solution of [16] and we present a secure and efficient fair e-cash system based on a group signature scheme Our system ensures traceability of double-spenders, supports coin tracing and provides coins that are unforgeable and anonymous under standard assumptions

Method for processing audio data and sound acquisition device implementing this method

Abstract: The invention concerns the processing of audio data. The invention is characterized in that it consists in: (a) encoding signals representing a sound propagated in three-dimensional space and derived from a source located at a first distance (P) from a reference point, to obtain a representation of the sound through components expressed in a spherical harmonic base, of origin corresponding to said reference point, (b) and applying to said components compensation of a near-field effect through filtering based on a second distance (R) defining, for sound reproduction, a distance between a reproduction point (HP i ), and a point (P) of auditory perception where a listener is usually located.

Signal transmission multiple antenna method and device

Abstract: The invention lies within the field of wireless communications systems with several transmitting antennas, corresponding to MIMO (Multiple Input Multiple Output) systems or to MISO (Multiple Input Single Output) systems. According to the invention, the symbols to be transmitted are pre-encoded with a particular linear pre-encoding matrix then coded according to space-time block coding so as to benefit to the full from temporal and spatial diversities allowing at reception for particularly easy and efficient linear decoding.

Method and system for real-time allocation of a resource among several entities

Abstract: A technique for the allocation and pricing of a resource among n buying agents during an auction bid. A bid sent by each buying agent in the form of a resource demand function si(p) is received, and a datum corresponding to the equilibrium price p* is calculated from the sum S of the n demand functions si(p), by means of the relation: S(p*)=Q. All of the bids received during a predetermined period corresponding to a round of bidding are processed in order to determine the quantity of a resource to be allocated to each buying agent. This is followed by the calculation of the data corresponding to the quantity ai to be allocated for this equilibrium price p* to each buying agent i based on its demand function si such that ai=si(p*). The management system utilizes the calculated data to allocate the corresponding quantities of the resource, and this data is stored in order to calculate the price to be billed to each buying agent.

Compact printed “patch” antenna

Abstract: A half-wave printed “patch” antenna includes, symmetrically with respect to a plane of symmetry of the antenna perpendicular to faces of the antenna, a dielectric substrate and two conductive layers on respective faces of the substrate. One face of the substrate includes a raised portion extending lengthwise of the plane of symmetry and one of the conductive layers extends over and along said raised portion. Consequently, the antenna has a small size, combined with a more open radiation diagram. The antenna includes only one raised portion for linear polarization, or two raised portions or a raised portion with axial symmetry for crossed polarizations.

Dynamic distributed method for local protection of a label-switching path

Abstract: The invention relates to a method for protection of a label-switching path in an MPLS network, comprising a plurality of nodes connected by means of IP connections, said path beginning at an entry node and terminating at a network exit node, passing through a determined series of nodes and connections in the network called pathway elements. When said entry node requires the protection of a pathway element, in a first phase, a node of said pathway called PLR point, upstream of said element to be protected, determines a rescue path, called a bypass tunnel, rejoining the pathway downstream of said element for protection, at a node called PM point and, in a second phase, network resources are reserved from each connection of the bypass tunnel to ensure said pathway in case of failure of said element.

Method for real-time broadcasting of multimedia files during a videoconference, without interrupting communication, and man-machine interface therefor

Abstract: The invention concerns a method of broadcasting data files, in particular multimedia files, during a video conference using a sending terminal and a man/machine interface located in the said terminal. According to the method proposed, the broadcasting of the files is effected in real time with a current video conference communication, without breaking this communication, using the audio and video channels open for this communication, a participant being able, using the said terminal, by means of a simple selection of the file appearing on his screen and movement of this, to activate the launch of the broadcasting of the file to be broadcast.

Charger and recharger device

Abstract: The invention concerns a portable charger (10) comprising a connection to an electric source, a plurality of connecting points (14 a , 14 b,) of rechargeable portable appliances for different usage, and an adapter (16), tapping power supply at the electric source and adapting it to the recharging supply of the rechargeable portable appliances, the adapter (16) including a microprocessor (22) and a multiple output converter delivering voltages and currents adapted to the appliances to be recharged, the adapter adapting the charge power to the portable appliance based on the charge programme delivered by the charger. The invention also concerns a recharge device comprising the portable charger. The invention enables simultaneous recharge of different rechargeable appliances in a manner adapted to each appliance. Thus the user of several rechargeable appliances needs only one charger.

Networks new economical virtual private

Abstract: The idea is to reduce costs without undermining quality of service.

Iterative decoding and channel estimation for space-time BICM over MIMO block fading multipath AWGN channel

Abstract: In this paper, we consider a generic model of space-time bit-interleaved coded modulation (ST-BICM) on a multiple-input multiple-output (MIMO) Rayleigh fading multipath channel. A practical low-complexity receiver structure performing iteratively MIMO data detection, channel decoding and channel estimation, is presented. The MIMO data detection, employing a reduced-state list-type soft output Viterbi algorithm enables to cope with severe channel intersymbol interference (ISI) without MIMO prefiltering. Among other results, simulations show that our approach can dramatically improve the downlink performance of time-division multiple access (TDMA) systems with high order modulation, keeping a reasonable complexity at the receiver side.

Analysis of ADSL traffic on an IP backbone link

Abstract: Measurements from an Internet backbone link carrying TCP traffic towards different ADSL areas are analyzed. For traffic analysis, we adopt a flow based approach and the popular mice/elephants dichotomy, where mice refer to short traffic transfers and elephants to long transfers. The originality of the reported experimental data, when compared with previous measurements from very high speed backbone links, is that the commercial traffic includes a significant part generated by peer-to-peer applications. This kind of traffic exhibits some remarkable properties in terms of mice and elephants, as we describe. It turns out that by adopting a suitable level of aggregation, the bit rate of mice can be described by means of a Gaussian process. The bit rate of elephants is smoother than that of mice and can also be well approximated by a Gaussian process.

Method and system with authentication, revocable anonymity and non-repudiation

Abstract: The present invention relates to a method of access to a service consisting in i) identifying and registering a client (C), ii) authenticating the client to an anonymous certification authority, iii) authenticating the client by producing an anonymous signature and opening and maintaining an anonymous authentication session with a server (Se), and iv) selectively allowing contact between the server (Se) and the anonymous certification authority (ACA) to revoke the anonymity of the client (C) using the signature provided in step iii). The invention also relates to a system for opening and maintaining an authentication session guaranteeing non-repudiation.

A traceable block cipher

Abstract: In this paper we propose a new symmetric block cipher with the following paradoxical traceability properties: it is computationally easy to derive many equivalent secret keys providing distinct descriptions of the same instance of the block cipher. But it is computationally difficult, given one or even up to k equivalent keys, to recover the so called meta-key from which they were derived, or to find any additional equivalent key, or more generally to forge any new untraceable description of the same instance of the block cipher. Therefore, if each legitimate user of a digital content distribution system based on encrypted information broadcast (e.g. scrambled pay TV, distribution over the Internet of multimedia content, etc.) is provided with one of the equivalent keys, he can use this personal key to decrypt the content. But it is conjectured infeasible for coalitions of up to k traitors to mix their legitimate personal keys into untraceable keys they might redistribute anonymously to pirate decoders. Thus, the proposed block cipher inherently provides an efficient traitor tracing scheme [4]. The new algorithm can be described as an iterative block cipher belonging to the class of multivariate schemes. It has advantages in terms of performance over existing traitor tracing schemes and furthermore, it allows to restrict overheads to one single block (i.e. typically 80 to 160 bits) per encrypted content payload. Its strength relies upon the difficulty of the “Isomorphism of Polynomials” problem [17], which has been extensively investigated over the past years. An initial security analysis is supplied.

Frame-based Gaussian beam summation method: Theory and applications

Abstract: [1] A discrete phase-space Gaussian beam summation representation for electromagnetic radiation from a planar source is presented. The formulation is based on the theory of frames and removes the inherent difficulties of the Gabor representation for both monochromatic and ultra wideband (UWB) fields. For monochromatic fields the frame-based representation leads to an efficient and flexible discrete Gaussian beam representation with local and stable expansion coefficients. For UWB fields a novel scaling of the frame overcompleteness parameter is introduced, leading to a new expansion that utilizes a discrete frequency-independent set of beams over the entire relevant spectrum. It is demonstrated that the isodiffracting Gaussian beams provide the snuggest frame representation over the entire spectrum. The rules for choosing the “optimal” frame and beam parameters for a given problem are discussed and demonstrated on application examples.

Computational aspects of balanced fairness

Abstract: Flow level behaviour of data networks depends on the allocation of link capacities between competing flows. It has been recently shown that there exist allocations with the property that the stationary distribution of the number of flows in progress on different routes depends only on the traffic loads on these routes and is insensitive to any detailed traffic characteristics. Balanced fairness refers to the most efficient of such allocations. In this paper we develop a general recursive algorithm for efficiently calculating the corresponding performance metrics like flow throughput. Several examples are worked out using this algorithm including the practically interesting case of concentration tree networks.

Simultaneous edge flipping in triangulations

Abstract: We generalize the operation of flipping an edge in a triangulation to that of flipping several edges simultaneously. Our main result is an optimal upper bound on the number of simultaneous flips that are needed to transform a triangulation into another. Our results hold for triangulations of point sets and for polygons.

Method and system for alerting call participant of a change in a call hold status

Abstract: A method and system for controlling a connection between a calling party and a called party. When a call is placed on hold, detection services are utilized to determine when the call changes from being “on hold” to being active. The call control system can then contact the caller to inform the caller of the change in the status of the call. Such contacts can be either in-band or out-of-band. If the caller is unable to respond to the change in call status, the called party can leave a message for the caller.

Adaptive patrol for a group of robots

Abstract: Patrolling is a basic task for a group of robots. All regions of an area are checked at regular interval and robots may look for intruders or garbage to collect. This work proposes a reactive and adaptive approach of this problem. In a virtual environment shared by robots, task data are propagated from place to place with modifications in order to represent locally distant-tasks value. A robot bas access to task data situated in the region where it stands and follows a gradient that guides it to valuable regions. First experiments on a simulator are presented. In addition of being efficient in achieving the work, the proposed architecture shows interesting properties of adaptability concerning the group size, the environment size and type.