Showing papers by "Orange S.A. published in 2000"

Efficient proofs that a committed number lies in an interval

Abstract: Alice wants to prove that she is young enough to borrow money from her bank, without revealing her age. She therefore needs a tool for proving that a committed number lies in a specific interval. Up to now, such tools were either inefficient (too many bits to compute and to transmit) or inexact (i.e. proved membership to a much larger interval). This paper presents a new proof, which is both efficient and exact. Here, "efficient" means that there are less than 20 exponentiations to perform and less than 2 Kbytes to transmit. The potential areas of application of this proof are numerous (electronic cash, group signatures, publicly verifiable secret encryption, etc ...).

Analytic evaluation of RED performance

Abstract: End-to-end congestion control mechanisms such as those in TCP are not enough to prevent congestion collapse in the Internet, and they must be supplemented by control mechanisms inside the network. The IRTF has singled out random early detection (RED) as one queue management scheme recommended for rapid deployment throughout the Internet. However, RED is not a thoroughly understood scheme-witness for example how the recommended parameter setting, or even the various benefits RED is claimed to provide, have changed over the past few years. In this paper, we describe simple analytic models for RED, and use these models to quantify the benefits (or lack thereof) brought about by RED. In particular, we examine the impact of RED on the loss and delay suffered by bursty and less bursty traffic (such as TCP and UDP traffic, respectively). We find that: (i) RED does eliminate the higher loss bias against bursty traffic observed with tail drop, but not by decreasing the loss rate of bursty traffic, rather by increasing that of non bursty traffic; (ii) the number of consecutive packet drops is higher with RED than tail drop, suggesting RED might not help as anticipated with the global synchronization of TCP flows; (iii) RED can be used to control the average queueing delay in routers and hence the end to end delay, but increases the jitter of non bursty streams. Thus, applications that generate smooth traffic, such as interactive audio applications, will suffer higher loss rates and require large playout buffers, thereby negating at least in part the lower mean delay brought about by RED.

Bandwidth sharing and admission control for elastic traffic

Abstract: We consider the performance of a network like the Internet handling so?called elastic traffic where the rate of flows adjusts to fill available bandwidth. Realized throughput depends both on the way bandwidth is shared and on the random nature of traffic. We assume traffic consists of point to point transfers of individual documents of finite size arriving according to a Poisson process. Notable results are that weighted sharing has limited impact on perceived quality of service and that discrimination in favour of short documents leads to considerably better performance than fair sharing. In a linear network, max---min fairness is preferable to proportional fairness under random traffic while the converse is true under the assumption of a static configuration of persistent flows. Admission control is advocated as a necessary means to maintain goodput in case of traffic overload.

Silicon-on-Nothing (SON)-an innovative process for advanced CMOS

Abstract: A novel CMOS device architecture called silicon on nothing (SON) is proposed, which allows extremely thin (in the order of a few nanometers) buried dielectrics and silicon films to be fabricated with high resolution and uniformity guaranteed by epitaxial process. The SON process' allows the buried dielectric (which may be an oxide but also an-air gap) to be fabricated locally in dedicated parts of the chip, which may present advantages in terms of cost and facility of system-on-chip integration. The SON stack itself is physically confined to the under-gate-plus-spacer area of a device, thus enabling extremely shallow and highly doped extensions, while leaving the HDD (highly doped drain) junctions comfortably deep. Therefore, SON embodies the ideal device architecture taking the best elements from both bulk and SOI and getting rid of their drawbacks. According to simulation results, SON enable ables excellent Ion/Ioff trade-off, suppressed self-heating, low S/D series resistance, close to ideal subthreshold slope, and high immunity to SCE and DIBL down to ultimate device dimensions of 30 to 50 nm.

Directional macro-cell channel characterization from urban measurements

Abstract: We measured the angular power distribution at the mobile station in downtown Paris at 890 MHz. The transmit antenna was omnidirectional and placed high above rooftops. The receiver antenna, a 21/spl times/41 element rectangular synthetic array, was located on the roof of a van. The refined high-resolution evaluation method, particularly robust against nonstationary signal components, allows an angular resolution of better than 1/spl deg/ in both azimuth and elevation and a delay resolution of 33 ns. Combined angular/temporal domain measurements are crucial for the understanding of the propagation mechanisms. The evaluated sites showed strongly street-dominated propagation. We found a combined circular and rectangular distribution of scatterers around the mobile station in street-dominated environments. Propagation over the roofs was significant; typically 65% of energy was incident with elevation larger than 100. Our results corroborate the hypothesis on the importance of multiple reflections/diffractions in urban macro cells. We explain this behavior by two reasons: narrow streets favoring a canyon effect and strong scatterers without line-of-sight (LOS) to the mobile station.

ASN.1 Communication Between Heterogeneous Systems

Abstract: I Introduction and History of the Notation 1 Prologue 2 Utilitarian Introduction to ASN.1 3 ASN.1 and the OSI Reference Model 4 Your First Steps with ASN.1 5 Basics of ASN.1 6 History 7 Protocols Specified in ASN.1 II User's Guide and Reference Manual 8 Introduction to the Reference Manual 9 Modules and Assignments 10 Basic Types 11 Character String Types 12 Constructed Types, Tagging, Extensibility Rules 13 Subtype Constraints 14 Presentation Context Switching Types 15 Information Object Classes, Objects, and Object Sets 16 Enough To Read Macros 17 Parameterization III Encoding Rules and Transfer Syntaxes 18 Basic Encoding Rules (BER) 19 Canonical and Distinguished Encoding Rules (CER and DER) 20 Packed Encoding Rules (PER) 21 Other Encoding Rules IV ASN.1 Applications 22 Tools 23 ASN.1 and the Formal Languages SDL, TTCN, GDMO 24 Other Abstract Syntax Notations 25 Epilogue V Appendices A Encoding/Decoding Simulations B Combined Use of ASN.1 and SDL

Cosine-modulated filterbanks based on extended Gaussian functions

Abstract: A new family of cosine-modulated filterbanks based on functions called extended Gaussian functions (EGFs) is obtained. The design is particularly simple since it is mainly based on a closed-form expression. Nearly perfect reconstruction cosine-modulated filterbanks are obtained as well as guidelines to estimate the filterbank parameters. This analytical design method can be used to produce, with a controlled accuracy, filterbanks with practically no upper limitations in the number of coefficients and subbands. Furthermore, a slight modification of the prototype filter coefficients is sufficient to satisfy exactly the perfect reconstruction constraints. An analysis of the time-frequency localization of the discrete prototype filters also shows that under certain conditions, EGF prototypes are at less than 0.3% from the optimal upper bound.

Method for making a semiconductor device comprising a stack alternately consisting of silicon layers and dielectric material layers

Abstract: The invention concerns a method for making a semiconductor device consisting of a silicon substrate whereon is formed a stack of layers. The stack comprises at least first and second successive assemblies each consisting, relative to the substrate, a thin lower SiGe layer and a thin upper silicon layer. It consists in forming on the thin upper silicon layer of the second assembly a thin silicon dioxide layer (18) so that said layer maintains the layers of the stack in place, at least on the two opposite lateral sides of the stack; then successively etching laterally and selectively the SiGe layers to form tunnels which are filled with a dielectric substance.

Hand gesture recognition using input-output hidden Markov models

Abstract: A new hand gesture recognition method based on input-output hidden Markov models is presented. This method deals with the dynamic aspects of gestures. Gestures are extracted from a sequence of video images by tracking the skin-color blobs corresponding to the hand into a body-face space centered on the face of the user. Our goal is to recognize two classes of gestures: deictic and symbolic.

Rewriting for Cryptographic Protocol Verification

Abstract: On a case study, we present a new approach for verifying cryptographic protocols, based on rewriting and on tree automata techniques. Protocols are operationally described using Term Rewriting Systems and the initial set of communication requests is described by a tree automaton. Starting from these two representations, we automatically compute an over-approximation of the set of exchanged messages (also recognized by a tree automaton). Then, proving classical properties like confidentiality or authentication can be done by automatically showing that the intersection between the approximation and a set of prohibited behaviors is the empty set. Furthermore, this method enjoys a simple and powerful way to describe intruder work, the ability to consider an unbounded number of parties, an unbounded number of interleaved sessions, and a theoretical property ensuring safeness of the approximation.

Method for thematic classification of documents, thematic classification module and search engine incorporating such a module

Abstract: The invention concerns a method for thematic classification of documents, in particular for constituting or updating thematic databases (42) for a search engine, comprising steps which consist in: selecting documents representing each theme; identifying in the selected documents elements characteristic of each theme; assigning to each identified element a coefficient (R) representing the relevance of said element relative to the corresponding theme; and, for each document (50) to be classified, identifying said elements characteristic of each theme it contains, and for each theme which corresponds to them, computing from the coefficient assigned to said elements, the value of a characteristic representative the relevance to the theme for said document (50) to determine whether said document is related or not to said theme.

Symbol and character recognition: application to engineering drawings

Abstract: In this paper, we consider the general problem of technical document interpretation, as applied to the documents of the French Telephonic Operator, France Telecom. More precisely, we focus the content of this paper on the computation of a new set of features allowing the classification of multioriented and multiscaled patterns. This set of invariants is based on the Fourier–Mellin Transform. The interests of this computation rely on the excellent classification rate obtained with this method and also on using this Fourier–Mellin transform within a “filtering mode”, with which we can solve the well known difficult problem of connected character recognition.

Analysis of the influence of the power control and discontinuous transmission on RF exposure with GSM mobile phones

Abstract: Biological studies and, in particular, epidemiological ones require the estimation of the RF exposure induced by a mobile phone. Due to the different techniques used by global system mobile (GSM) and digital communication system (DCS) such as power control and discontinuous transmission, the power emitted by a handset is largely variable. As these parameters depend on the environment and the network strategy, individual exposure level is difficult to evaluate a priori. An analysis of the relative influence of the main parameters is performed and a method of statistical analysis based on measurement is proposed to estimate and characterize the exposure level in an operating network. Using a test mobile system, the data stream between the mobile and the base station, and, in particular the power control level, has been recorded along routes in Paris and its vicinity. Statistical parameters such as mean value, standard deviation, level crossing rate, and average duration fading have been extracted from these data. These parameters, which characterize the RF exposure induced by a GSM handset in an operating network, have been applied to a generic handset to evaluate the characteristics of the power absorbed by specific biological tissues using the finite-difference time-domain (FDTD) method.

Confiance interpersonnelle et engagement : Une réorientation béhavioriste:

Abstract: La relation entre confiance interpersonnelle et engagement est devenue depuis les travaux de Morgan et Hunt (1994) le modele cognitif de reference du marketing relationnel. Cet article developpe et...

Electronic payment process and system for implementing this process

Abstract: Electronic payment process and system for implementing such a process. Customer equipment is mobile equipment, for example of the GSM type. In addition to the customer (C) and the merchant (M), a gateway (P) participates in the transaction, authenticates the customer and the merchant and ensures that the goods item ordered will be duly paid for. Customer equipment may work with a bank payment card.

Study on the Implementation of Optical Transparent Transport Networks in the European Environment—Results of the Research Project COST 239

Abstract: This paper reports the main results obtained in the framework of the COST239 project on the implementation of transparent optical network schemes to connect main European cities. The investigation on transmission limitations has shown that transmission systems, for which 1662:5 Gbit/s WDM systems are used due to traf®c reasons, have a maximum range shorter than 1000 km. This condition does not allow a completely transparent network. Two solutions, the partitioned and the gridconnected network architecture, are proposed, described, and compared in the paper.

MPEG-4's binary format for scene description

Abstract: The new MPEG-4 standard provides a suite of functionalities under one standard: streaming multimedia content, good compression, and user interactivity. This paper provides an introduction to the use and internal mechanisms of these functions.

Quality of Service by flow–aware networking

Abstract: The paper addresses the issue of providing Quality of Service (QoS) guarantees in the Internet. After a brief discussion of Internet traffic characteristics, we consider the possibility of performing multiplexing with predictable performance for stream and elastic traffic using open–loop and closed–loop control, respectively. QoS depends essentially on providing sufficient capacity to handle expected demand. We argue that flow awareness is additionally necessary to ensure that traffic is directed over routes with available capacity and to avoid congestion collapse in case of overload. Proposed flow–aware controls allow simple volume–based charging and the development of an economic model similar to that of the telephone network.

Infrared second-order optical susceptibility in InAs/GaAs self-assembled quantum dots

Abstract: We have investigated the second-order nonlinear susceptibility in self-assembled quantum dots. The nonlinear susceptibility associated with intraband transitions in the conduction band and in the valence band is theoretically estimated for lens-shaped InAs/GaAs self-assembled quantum dots. The confined energy levels in the dots are calculated in the effective-mass approximation by solving the three-dimensional Schr\"odinger equation. Giant values of nonlinear susceptibility, about six orders of magnitude larger than the bull GaAs susceptibility, are predicted. We show that this enhancement results from three key features: (i) the achievement of the double resonance condition, (ii) the specific polarization selection rules of intraband transitions that allow both in-plane and z-polarized transitions with large dipole matrix elements to be optically active, and (iii) the small homogeneous linewidth of the intraband transitions. The conclusions of the calculations are supported by the measurement of the midinfrared nonlinear susceptibility in the valence band. The measurements have been performed using a picosecond free-electron laser. Both ${\ensuremath{\chi}}_{\mathrm{zzz}}^{(2)}$ and ${\ensuremath{\chi}}_{\mathrm{zxx}}^{(2)}$ components of the susceptibility tensor are observed. A satisfying agreement is found between theoretical and experimental values.

A fast and accurate face detector for indexation of face images

Abstract: Detecting faces in images with complex backgrounds is a difficult task. Our approach, which obtains state-of-the-art results, is based on a generative neural network model: the constrained generative model (CGM). To detect side-view faces and to decrease the number of false alarms, a conditional mixture of networks is used. To decrease the computational time cost, a fast search algorithm is proposed. The level of performance reached, in terms of detection accuracy and processing time, allows us to apply this detector to a real-world application: the indexation of face images on the WWW.

IP telephony: packet-based multimedia communications systems

Abstract: I recommend this book to all VoIP engineers, analysts, and IT managers who really want to know what they are talking about on the net, enjoy!" -Jeff Pulver, founder of the VON (Voice On the Net) coalition, and the founder and president of pulver.comInternet Telephony is now one of the most important and fastest growing technologies on the Internet, providing a viable technical and economical alternative to current telecommunication networks. Network providers and major companies are thus investigating how this emerging technology can be implemented, and at what cost and savings, in their organizations. This book provides a comprehensive practical overview of the technology behind Internet Telephony, giving essential information to IT professionals who need to understand the background and explore the issues involved in migrating the existing telephony infrastructure to an IP based real time communication service. Assuming a working knowledge of IP and ISDN networking, it addresses the technical aspects of real-time applications over IP, with an in-depth coverage of voice and video applications and protocols. Drawing on their extensive research and practical development experience in VoIP from its earliest stages, the authors give you access to all the relevant standards and cutting-edge techniques in a single resource. IP Telephony is organized into three clearly structured sections, focusing on protocols, voice technology and networks with a step-by-step approach. The protocols section sets IP telephony in context and then covers H.323, SIP and MGCP in detail, examining in turn their pros and cons, and using examples of particular cases and scenarios. The voice technology section describes voice quality, including the ETSI TIPHON approach, and voice coding, with summary comments on the applicability to VoIP telephone gateways. The final section on networks addresses Quality of Service (QoS) issues, explores dimensioning a VoIP network, and introduces Multicast routing, including a perspective on security and MBONE applications.

Resource sharing of TCP connections with different round trip times

Abstract: The performance of TCP connections sharing a common link and the resulting link usage depends on the various round trip times along the connections. Expressions exist for these values only in the homogenous case and heuristics for the general case give uncertain results. In this paper we first derive an exact expression (in the setting of fluid models) for the window evolution of TCP connections with different round trip delays. We next apply this result in a particular context to derive expressions for the maximum window sizes and the throughput of TCP connections as well the idle periods and the utilization of the shared link. We show that a bias in favor of connections with short round trip delays persists even for large buffer sizes. First- and second-order approximations in buffer size are given respectively for small and large buffers. These expressions show that for small buffers small round trip times predominate in global performance while the opposite is true for large buffers.

System for fast development of interactive applications

Abstract: The invention concerns a system for developing interactive applications transmitted through a network. The system comprises, activated by the operation of a computer, an electronic editor (E) for simulating a display screen of a display monitor, and an interface controlling (MCS) a control module associated with said display monitor. A module generating virtual objects (GOV) specific to the application to be developed is provided, the virtual objects being selected at least among images in point mode, video files, textual files, capable of being edited, displayed, represented by the editor (E) for forming a scene of the pplication. A control module (COR) for correlating event/action pairs is provided, an event corresponding to the imbalance of the state of an operation system and an action corresponding to an initialization or a modification of the display or the representation of one or several scenes constituting the applications. The invention is useful for developing interactive applications, in particular on TV channel, Internet network or the like.

An Online Public Auction Protocol Protecting Bidder Privacy

Abstract: On-line auctioning is one of the fundamental services for the new Internet economy. Most current auction services are public auction where all bids are made available to any party. User privacy is a primary concern in electronic world because electronic environment facilitates the gathering of personal data. This paper proposes a public auction protocol that achieves bidder privacy using binding group signatures. A concrete solution for preventing defaults in auctions is also presented.

Method of and apparatus for processing at least one coded binary audio flux organized into frames

Abstract: At least one coded binary audio flux organized into frames is created from digital audio signals which were coded by transforming them from the time domain into the frequency domain. Transform coefficients of the signals in the frequency domain are quantized and coded according to a set of quantizers. The set is determined from a set of values extracted from the signals. The values make up selection parameters of the set of quantizers. The parameters are also present in the frames. A partial decoding state decodes then dequantizes transform coefficients produced by the coding based on a set of quantizers determined from the selection parameters contained in the frames of the coded binary audio flux or of each coded binary audio flux. The partially decoded frames are subjected to processing in the frequency domain. The thus-processed frames are then made available for use in a later utilization step.

Efficient compilation of ESTEREL for real-time embedded systems

Abstract: This paper presents a new method for compiling the concurrent synchronous language Esterel into sequential C code. The method is optimized for embedded systems with very tight memory and real-time constraints. Source code is sliced into small code sequences called halt points, statically scheduled so as to be compatible with Esterel semantic. Speed reaction is optimized without increasing code size, by executing at each reaction only active code sequences. Performances are compared to other compilation methods with industrial size examples and results show significant performance improvement.