Showing papers by "Orange S.A. published in 2006"

The FRACTAL component model and its support in Java

Abstract: This paper presents FRACTAL, a hierarchical and reflective component model with sharing. Components in this model can be endowed with arbitrary reflective capabilities, from plain black-box objects to components that allow a fine-grained manipulation of their internal structure. The paper describes JULIA, a Java implementation of the model, a small but efficient runtime framework, which relies on a combination of interceptors and mixins for the programming of reflective features of components. The paper presents a qualitative and quantitative evaluation of this implementation, showing that component-based programming in FRACTAL can be made very efficient. Copyright © 2006 John Wiley & Sons, Ltd.

Advanced integration of WIFI and inertial navigation systems for indoor mobile positioning

Abstract: This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS) are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

The FRACTAL component model and its support in Java: Experiences with Auto-adaptive and Reconfigurable Systems

Abstract: This paper presents F RACTAL, a hierarchical and reflective component model with sharing. Components in this model can be endowed with arbitrary reflective capabilities, from plain black-box objects to components that allow a fine-grained manipulation of their internal structure. The paper describes J ULIA, a Java implementation of the model, a small but efficient runtime framework, which relies on a combination of interceptors and mixins for the programming of reflective features of components. The paper presents a qualitative and quantitative evaluation of this implementation, showing that component-based programming in F RACTAL can be made very efficient. Copyright © 2006 John Wiley & Sons, Ltd.

Improved Signal-to-Noise Ratio Estimation for Speech Enhancement

Abstract: This paper addresses the problem of single-microphone speech enhancement in noisy environments. State-of-the-art short-time noise reduction techniques are most often expressed as a spectral gain depending on the signal-to-noise ratio (SNR). The well-known decision-directed (DD) approach drastically limits the level of musical noise, but the estimated a priori SNR is biased since it depends on the speech spectrum estimation in the previous frame. Therefore, the gain function matches the previous frame rather than the current one which degrades the noise reduction performance. The consequence of this bias is an annoying reverberation effect. We propose a method called two-step noise reduction (TSNR) technique which solves this problem while maintaining the benefits of the decision-directed approach. The estimation of the a priori SNR is refined by a second step to remove the bias of the DD approach, thus removing the reverberation effect. However, classic short-time noise reduction techniques, including TSNR, introduce harmonic distortion in enhanced speech because of the unreliability of estimators for small signal-to-noise ratios. This is mainly due to the difficult task of noise power spectrum density (PSD) estimation in single-microphone schemes. To overcome this problem, we propose a method called harmonic regeneration noise reduction (HRNR). A nonlinearity is used to regenerate the degraded harmonics of the distorted signal in an efficient way. The resulting artificial signal is produced in order to refine the a priori SNR used to compute a spectral gain able to preserve the speech harmonics. These methods are analyzed and objective and formal subjective test results between HRNR and TSNR techniques are provided. A significant improvement is brought by HRNR compared to TSNR thanks to the preservation of harmonics

A queueing analysis of max-min fairness, proportional fairness and balanced fairness

Abstract: We compare the performance of three usual allocations, namely max-min fairness, proportional fairness and balanced fairness, in a communication network whose resources are shared by a random number of data flows. The model consists of a network of processor-sharing queues. The vector of service rates, which is constrained by some compact, convex capacity set representing the network resources, is a function of the number of customers in each queue. This function determines the way network resources are allocated. We show that this model is representative of a rich class of wired and wireless networks. We give in this general framework the stability condition of max-min fairness, proportional fairness and balanced fairness and compare their performance on a number of toy networks.

Improving test suites for efficient fault localization

Abstract: The need for testing-for-diagnosis strategies has been identified for a long time, but the explicit link from testing to diagnosis (fault localization) is rare. Analyzing the type of information needed for efficient fault localization, we identify the attribute (called Dynamic Basic Block) that restricts the accuracy of a diagnosis algorithm. Based on this attribute, a test-for-diagnosis criterion is proposed and validated through rigorous case studies: it shows that a test suite can be improved to reach a high level of diagnosis accuracy. So, the dilemma between a reduced testing effort (with as few test cases as possible) and the diagnosis accuracy (that needs as much test cases as possible to get more information) is partly solved by selecting test cases that are dedicated to diagnosis.

Comparisons of computed mobile phone induced SAR in the SAM phantom to that in anatomically correct models of the human head

Abstract: The specific absorption rates (SAR) determined computationally in the specific anthropomorphic mannequin (SAM) and anatomically correct models of the human head when exposed to a mobile phone model are compared as part of a study organized by IEEE Standards Coordinating Committee 34, Sub-Committee 2, and Working Group 2, and carried out by an international task force comprising 14 government, academic, and industrial research institutions. The detailed study protocol defined the computational head and mobile phone models. The participants used different finite-difference time-domain software and independently positioned the mobile phone and head models in accordance with the protocol. The results show that when the pinna SAR is calculated separately from the head SAR, SAM produced a higher SAR in the head than the anatomically correct head models. Also the larger (adult) head produced a statistically significant higher peak SAR for both the 1- and 10-g averages than did the smaller (child) head for all conditions of frequency and position.

A survey of algebraic properties used in cryptographic protocols

Abstract: Cryptographic protocols are successfully analyzed using formal methods. However, formal approaches usually consider the encryption schemes as black boxes and assume that an adversary cannot learn anything from an encrypted message except if he has the key. Such an assumption is too strong in general since some attacks exploit in a clever way the interaction between protocol rules and properties of cryptographic operators. Moreover, the executability of some protocols relies explicitly on some algebraic properties of cryptographic primitives such as commutative encryption. We give a list of some relevant algebraic properties of cryptographic operators, and for each of them, we provide examples of protocols or attacks using these properties. We also give an overview of the existing methods in formal approaches for analyzing cryptographic protocols.

MODL: A Bayes optimal discretization method for continuous attributes

Abstract: While real data often comes in mixed format, discrete and continuous, many supervised induction algorithms require discrete data. Efficient discretization of continuous attributes is an important problem that has effects on speed, accuracy and understandability of the induction models. In this paper, we propose a new discretization method MODL1, founded on a Bayesian approach. We introduce a space of discretization models and a prior distribution defined on this model space. This results in the definition of a Bayes optimal evaluation criterion of discretizations. We then propose a new super-linear optimization algorithm that manages to find near-optimal discretizations. Extensive comparative experiments both on real and synthetic data demonstrate the high inductive performances obtained by the new discretization method.

Dynamic fully anonymous short group signatures

Abstract: Group signatures allow members to sign on behalf of a group. Recently, several schemes have been proposed, in order to provide more efficient and shorter group signatures. However, this should be performed achieving a strong security level. To this aim, a formal security model has been proposed by Bellare, Shi and Zang, including both dynamic groups and concurrent join. Unfortunately, very few schemes satisfy all the requirements, and namely the shortest ones needed to weaken the anonymity notion. We present an extremely short dynamic group signature scheme, with concurrent join, provably secure in this model. It achieves stronger security notions than BBS, and namely the full anonymity, while still shorter. The proofs hold under the q-SDH and the XDH assumptions, in the random oracle model.

Secure advanced video coding based on selective encryption algorithms

Abstract: Advanced video coding is recently announced and widely used, although the according protection means have not been developed thoroughly. In this paper, a secure AVC coding scheme is presented based on some partial encryption algorithms. During AVC encoding, such sensitive data as intra-prediction mode, residue data and motion vector are encrypted partially. Among them, the infra-prediction mode is encrypted based on exp-Golomb entropy coding, the intra-macroblocks' DCs are encrypted based on context-based adaptive variable length coding (CAVLC), and infra-macroblocks' ACs and the inter-macroblocks' MVDs are sign-encrypted with a stream cipher followed with variable-length coding. This encryption scheme is secure in perception, keeps format compliance, and obtains high time efficiency though reducing the encrypted data volumes. These properties make it practical to incorporate encryption/decryption process into compression/decompression process, and thus suitable for secure video transmission or sharing.

Speech recognition method, device, and computer program

Abstract: A speech recognition method including for a spoken expression: a) providing a vocabulary of words including predetermined subsets of words, b) assigning to each word of at least one subset an individual score as a function of the value of a criterion of the acoustic resemblance of that word to a portion of the spoken expression, c) for a plurality of subsets, assigning to each subset of the plurality of subsets a composite score corresponding to a sum of the individual scores of the words of said subset, d) determining at least one preferred subset having the highest composite score.

Methods and apparatus for gathering and delivering contextual messages in a mobile communication system

Abstract: Methods and apparatus for delivering personalized (e.g., contextual) messages to a user that meets certain geographic, affiliation/metadata, timing, and/or or other criteria. These messages are geographically and logically persistent, and can be left by members of the user's social or “buddy” network, individuals, institutions, the user's service provider(s), or even advertisers or others seeking a commercial opportunity. These messages can be rendered in the form of voice, video, audio (e.g., MP3), text and graphics delivered to mobile phones, PDA's or other devices with network connectivity. Exemplary embodiments of the invention incorporate existing geo-localization technologies such as GPS embedded in these mobile platforms, or triangulation via signals from the cellular/PCS networks, IP addressing, presence in ad hoc networks, cell ID, E911/E112, Time of Arrival (TOA), Time Difference of Arrival (TDOA), Observed Time Difference (OTD) and Angle of Arrival (AOA).

Metamodel-based Test Generation for Model Transformations: an Algorithm and a Tool

Abstract: In a Model-Driven Development context (MDE), model transformations allow memorizing and reusing design know-how, and thus automate parts of the design and refinement steps of a software development process. A model transformation program is a specific program, in the sense it manipulates models as main parameters. Each model must be an instance of a "metamodel", a metamodel being the specification of a set of models. Programming a model transformation is a difficult and error-prone task, since the manipulated data are clearly complex. In this paper, we focus on generating input test data (called test models) for model transformations. We present an algorithm to automatically build test models from a metamodel.

A formal model for semantic web service composition

Abstract: Automated composition of Web services or the process of forming new value added Web services is one of the most promising challenges in the semantic Web service research area. Semantics is one of the key elements for the automated composition of Web services because such a process requires rich machine-understandable descriptions of services that can be shared. Semantics enables Web service to describe their capabilities and processes, nevertheless there is still some work to be done. Indeed Web services described at functional level need a formal context to perform the automated composition of Web services. The suggested model (i.e., Causal link matrix) is a necessary starting point to apply problem-solving techniques such as regression-based search for Web service composition. The model supports a semantic context in order to find a correct, complete, consistent and optimal plan as a solution. In this paper an innovative and formal model for an AI planning-oriented composition is presented.

On the Fly Authentication and Signature Schemes Based on Groups of Unknown Order

Abstract: In response to the current need for fast, secure and cheap public-key cryptography, we propose an interactive zero-knowledge identification scheme and a derived signature scheme that combine provable security based on the problem of computing discrete logarithms in any group, short keys, very short transmission and minimal on-line computation. This leads to both efficient and secure applications well suited to implementation on low cost smart cards. We introduce GPS, a Schnorr-like scheme that does not require knowledge of the order of the group nor of the group element. As a consequence, it can be used with most cryptographic group structures, including those of unknown order. Furthermore, the computation of the prover's response is done over the integers, hence can be done with very limited computational capabilities. This paper provides complete security proofs of the identification scheme. From a practical point of view, the possible range of parameters is discussed and a report on the performances of an actual implementation on a cheap smart card is included: a complete and secure authentication can be performed in less than 20 milliseconds with low cost equipment.

Feasibility of future epidemiological studies on possible health effects of mobile phone base stations

Abstract: The increasing deployment of mobile communication base stations led to an increasing demand for epidemiological studies on possible health effects of radio frequency emissions. The methodological challenges of such studies have been critically evaluated by a panel of scientists in the fields of radiofrequency engineering/dosimetry and epidemiology. Strengths and weaknesses of previous studies have been identified. Dosimetric concepts and crucial aspects in exposure assessment were evaluated in terms of epidemiological studies on different types of outcomes. We conclude that in principle base station epidemiological studies are feasible. However, the exposure contributions from all relevant radio frequency sources have to be taken into account. The applied exposure assessment method should be piloted and validated. Short to medium term effects on physiology or health related quality of life are best investigated by cohort studies. For long term effects, groups with a potential for high exposure need to first be identified; for immediate effect, human laboratory studies are the preferred approach.

Cyclostatilonarilty-Based Test for Detection of Vacant Frequency Bands

Abstract: The problem addressed in this paper is the test for presence of any telecommunication signal within a given frequency band, which is of great importance for cognitive radios. Since a telecommunication signal is well modeled as cyclostationary, we transform this problem to the one of testing for presence of the cyclostationary property over a range of cyclic frequencies and we propose a constant false alarm rate (CFAR) multicycle detector based on a chi-squared (x2) statistical test of the time varying covariance estimate.

An aspect-oriented approach for developing self-adaptive fractal components

Abstract: Nowadays, application developers have to deal with increasingly variable execution contexts, requiring the creation of applications able to adapt themselves autonomously to the evolutions of this context. In this paper, we show how an aspect-oriented approach enables the development of self-adaptive applications where the adaptation code is well modularized, both spatially and temporally. Concretely, we propose SAFRAN, an extension of the Fractal component model for the development of the adaptation aspect as reactive adaptation policies. These policies detect the evolutions of the execution context and adapt the base program by reconfiguring it. This way, SAFRAN allows the modular development of adaptation policies and their dynamic weaving into running applications.

A product, service and activity based interactive trip mapping system, method and computer program product

Abstract: A system, method, and computer program product for generating a travel itinerary, including specifying a criteria for a query including a start point and an end point of the travel itinerary, and at least one route point, the route point being a service, a product, a place, an activity, or an event. An interactive mapping system is queries with the criteria to obtain information defining the travel itinerary including mapping information and route point descriptive information including consumer information related to the route point. The travel itinerary is displayed as a map, driving instructions, or the consumer information.

Classification of movement intention by spatially filtered electromagnetic inverse solutions

Abstract: We couple standardized low-resolution electromagnetic tomography, an inverse solution for electroencephalography (EEG) and the common spatial pattern, which is here conceived as a data-driven beamformer, to classify the benchmark BCI (brain-computer interface) competition 2003, data set IV. The data set is from an experiment where a subject performed a self-paced left and right finger tapping task. Available for analysis are 314 training trials whereas 100 unlabelled test trials have to be classified. The EEG data from 28 electrodes comprise the recording of the 500 ms before the actual finger movements, hence represent uniquely the left and right finger movement intention. Despite our use of an untrained classifier, and our extraction of only one attribute per class, our method yields accuracy similar to the winners of the competition for this data set. The distinct advantages of the approach presented here are the use of an untrained classifier and the processing speed, which make the method suitable for actual BCI applications. The proposed method is favourable over existing classification methods based on an EEG inverse solution, which rely either on iterative algorithms for single-trial independent component analysis or on trained classifiers.

QUAD: a practical stream cipher with provable security

Abstract: We introduce a practical stream cipher with provable security named QUAD. The cipher relies on the iteration of a multivariate quadratic system of m equations in n < m unknowns over a finite field. The security of the keystream generation of QUAD is provably reducible to the conjectured intractability of the MQ problem, namely solving a multivariate system of quadratic equations. Our recommended version of QUAD uses a 80-bit key, 80-bit IV and an internal state of n = 160 bits. It outputs 160 keystream bits (m = 320) at each iteration until 240 bits of keystream have been produced.

Methods and apparatus for providing privacy in a communication system

Abstract: Methods and apparatus for providing privacy during video or other communication across a network. In one embodiment, a system is disclosed wherein digital video camera is coupled to a network via a processing server. The digital video camera generates one or more digital images that are processed by the processing server, including identifying and obstructing any artifacts (e.g., faces, hands, etc.) in the images. The processing also optionally includes the tracking of the artifacts in the images as they move within the image, as well as search for new faces that may enter the field of view. In another embodiment of the invention, video conferencing is performed over a network between two or more users. Images are generated by digital video cameras and processed by video servers. During the videoconference, one or more users may select a video (and audio) muting mode during which any artifacts of interest in the images (or portions thereof) are identified and obscured. Business methods utilizing these capabilities are also disclosed.

QUAD : A practical stream cipher with provable security

Abstract: We introduce a practical stream cipher with provable security named QUAD. The cipher relies on the iteration of a multivariate quadratic system of m equations in n < m unknowns over a finite field. The security of the keystream generation of QUAD is provably reducible to the conjectured intractability of the MQ problem, namely solving a multivariate system of quadratic equations. Our recommended version of QUAD uses a 80-bit key, 80-bit IV and an internal state of n = 160 bits. It outputs 160 keystream bits (m = 320) at each iteration until 2 40 bits of keystream have been produced.

Mutation analysis testing for model transformations

Abstract: In MDE, model transformations should be efficiently tested so that it may be used and reused safely. Mutation analysis is an efficient technique to evaluate the quality of test data, and has been extensively studied both for procedural and object-oriented languages. In this paper, we study how it can be adapted to model oriented programming. Since no model transformation language has been widely accepted today, we propose generic fault models that are related to the model transformation process. First, we identify abstract operations that constitute this process: model navigation, model's elements filtering, output model creation and input model modification. Then, we propose a set of specific mutation operators which are directly inspired from these operations. We believe that these operators are meaningful since a large part of the errors in a transformation are due to the manipulation of complex models regardless of the concrete implementation language.

Auto adaptive quality of service architecture & associated method of provisioning customer premises traffic

Abstract: A customer premises device is provided for monitoring quality of service (QOS) metrics between a network edge and a customer. The device includes a memory which stores at least one user profile, and, information regarding active sessions of traffic flow through the customer premises device. A hardware and/or software/firmware based controller monitors traffic flow between the customer and the network edge and receives requests for new active sessions. The processor accesses the at least one user profile stored in memory to identify a policy hierarchy with respect to active sessions of traffic flow upon receipt of a request to establish a new active session. The processor selects a candidate active session to be terminated based upon the policy hierarchy and terminates the selected session in accordance with information stored in memory regarding the selected session. In this manner, the processor enforces quality of service, for both upstream and downstream sessions, based upon the policy hierarchy of the user profile.

Overview of the optical broadband access evolution: a joint article by operators in the IST network of excellence e-Photon/One

Abstract: This article presents an operators' view of the evolution towards broadband optical access networks. First, we describe a possible evolution of the optical access solution for point-to-point and point-to-multipoint architectures. Subsequently, currently available optical access solutions are evaluated and compared. Finally, we consider regulatory issues inside and outside Europe, and conclude by offering a recommendation with respect to regulation

Blind adaptive channel estimation in ofdm systems

Abstract: We consider the problem of blind channel estimation in zero padding OFDM systems, and propose blind adaptive algorithms in order to identify the impulse response of the multipath channel. In particular, we develop RLS and LMS schemes that exhibit rapid convergence combined with low computational complexity and numerical stability. Both versions are obtained by properly modifying the orthogonal iteration method used in numerical analysis for the computation of singular vectors. With a number of simulation experiments we demonstrate the satisfactory performance of our adaptive schemes under diverse signaling conditions

Peer to peer size estimation in large and dynamic networks: A comparative study

Abstract: As the size of distributed systems keeps growing, the peer to peer communication paradigm has been identified as the key to scalability. Peer to peer overlay networks are characterized by their self-organizing capabilities, resilience to failure and fully decentralized control. In a peer to peer overlay, no entity has a global knowledge of the system. As much as this property is essential to ensure the scalability, monitoring the system under such circumstances is a complex task. Yet, estimating the size of the system is core functionality for many distributed applications to parameter setting or monitoring purposes. In this paper, we propose a comparative study between three algorithms that estimate in a fully decentralized way the size of a peer to peer overlay. Candidate approaches are generally applicable irrespective of the underlying structure of the peer to peer overlay. The paper reports the head to head comparison of estimation system size algorithms. The simulations have been conducted using the same simulation framework and inputs and highlight the differences in cost and accuracy of the estimation between the algorithms both in static and dynamic settings