Orange S.A.

About: Orange S.A. is a company organization based out in Paris, France. It is known for research contribution in the topics: Terminal (electronics) & Signal. The organization has 6735 authors who have published 9190 publications receiving 156440 citations. The organization is also known as: Orange SA & France Télécom.

An accurate and repeatable technique for noise parameter measurements

Abstract: In spite of the improvements in RF instrumentation, network analyzer calibration methods, and measurement techniques, the measurement of noise parameters in highly mismatched systems is particularly prone to error. A homemade automated noise parameter measurement system is described, and a new algorithm for the estimation of the two-port noise parameters is presented. Analytical calculation of the parameter accuracy is developed, by taking into account the measurement uncertainties. The accuracy and the repeatability of the measurements performed with a low-noise HEMT are presented. >

ALIF: A dataset for Arabic embedded text recognition in TV broadcast

Abstract: This paper proposes a dataset, called ALIF, for Arabic embedded text recognition in TV broadcast. The dataset is publicly available for a non-commercial use. It is composed of a large number of manually annotated text images that were extracted from Arabic TV broadcast. It is the first public dataset dedicated to the development and the evaluation of video Arabic OCR techniques. Text images in the dataset are highly variable in terms of text characteristics (fonts, sizes, colors…) and acquisition conditions (background complexity, low resolution, non-uniform luminosity and contrast…). Moreover, an important part of the dataset is finely annotated, i.e. the text in an image is segmented into characters, paws and words, and each segment is labeled. The dataset can hence be used for both segmentation-based and segmentation-free text recognition techniques. In order to illustrate how the ALIF dataset can be used, the results of an evaluation study that we have conducted on different techniques for Arabic text recognition are also presented.

Quality of experience model for 3DTV

Abstract: Modern stereoscopic 3DTV brings new QoE (quality of experience) to viewers, which not only enhances the 3D sensation due to the added binocular depth, but may also induce new problems such as visual discomfort. Subjective quality assessment is the conventional method to assess the QoE. However, the conventional perceived image quality concept is not enough to reveal the advantages and the drawbacks of stereoscopic images in 3DTV. Higher-level concepts such as visual experience were proposed to represent the overall visual QoE for stereoscopic images. In this paper, both the higher-level concept quality indicator, i.e. visual experience and the basic level concepts quality indicators including image quality, depth quantity, and visual comfort are defined. We aim to explore 3D QoE by constructing the visual experience as a weight sum of image quality, depth quantity and visual comfort. Two experiments in which depth quantity and image quality are varied respectively are designed to validate this model. In the first experiment, the stimuli consist of three natural scenes and for each scene, there are four levels of perceived depth variation in terms of depth of focus: 0, 0.1, 0.2 and 0.3 diopters. In the second experiment, five levels of JPEG 2000 compression ratio, 0, 50, 100, 175 and 250 are used to represent the image quality variation. Subjective quality assessments based on the SAMVIQ method are used in both experiments to evaluate the subject's opinion in basic level quality indicators as well as the higher-level indicator. Statistical analysis of result reveals how the perceived depth and image quality variation affect different perceptual scales as well as the relationship between different quality aspects.

On Using Matching Theory to Understand P2P Network Design

Abstract: This paper aims at giving insight on the stability of collaboration choices in P2P networks. We study networks where exchanges between nodes are driven by the will of getting the best service available. This is the case for most existing P2P networks. We explore an evolution model derived from stable roommates theory that accounts for heterogeneity between nodes. We show that most P2P applications can be modeled using stable matching theory. This is the case whenever preference lists can be deduced from the exchange policy. In many cases, the preferences lists are characterized by an interesting acyclic property. This leads us to the notion of acyclic preferences. We show that P2P networks with acyclic preferences possess a unique stable state with good convergence properties.

High isolation, optical add-drop multiplexer

Abstract: According to the invention, a first band-pass multidielectric filter (F1) receives optical signals, transmits at least one of them and reflects the untransmitted signals. An adding means (F2) inserts among them at least one other optical signal. A photoinduced Bragg grating filter (R) receives the signals reflected by the first filter and transmits them to the adding means and reflects any optical signal of the same wavelength as the signal transmitted by the first filter and which is liable to exist among the signals reflected by it. Application to optical telecommunications.