90 results on '"Bijaoui, A."'
Search Results
2. From a 'Society of Scholars' to a Credential Society? The Perceptions of Ultra-Orthodox Students in Israel, regarding HigherEducation and its Influence on Work and Family - a Gender Perspective Evaluation Culture in Organizational Change of Schooling
- Author
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Yael Yossel Eisenbach and Sylvie Fogiel Bijaoui
- Subjects
Work (electrical) ,business.industry ,Perception ,media_common.quotation_subject ,Organizational change ,Perspective (graphical) ,Sociology ,Ultra orthodox ,Public relations ,business ,Credential ,media_common - Published
- 2019
3. International Trade and FDI
- Author
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Ilan Bijaoui
- Subjects
business.industry ,Value (economics) ,Economics ,media_common.cataloged_instance ,Foreign direct investment ,International trade ,European union ,business ,Trade barrier ,media_common - Abstract
The evolution of international trade and foreign investment in Sub-Saharan African (SSA) countries expresses the ability to generate value and create the conditions for attracting new partners with the relevant knowledge required to globalize the economy.
- Published
- 2017
4. SMEs in an Era of Globalization
- Author
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Ilan Bijaoui
- Subjects
Globalization ,business.industry ,Business ,International trade - Published
- 2017
5. Economic Involvement of International Organizations, MNCs and Local Business Leaders and Groups
- Author
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Ilan Bijaoui
- Subjects
education.field_of_study ,Economic growth ,business.industry ,Population ,Private equity firm ,Private equity ,Multinational corporation ,General partnership ,Agency (sociology) ,media_common.cataloged_instance ,Economic system ,European union ,business ,education ,International development ,media_common - Abstract
The international funding organizations try to have a positive impact on the population of Sub-Saharan Africa (SSA) by improving the economic situation in their countries. Each organization has a different approach. Herewith I analyse the approaches of the African Development Bank (AfDB) , the World Bank, the United States Agency for International Development ( USAID) , the European Union (EU) , New Partnership for Africa's Development (NEPAD) and Japan International Cooperation Agency ( JICA) .
- Published
- 2017
6. All-sky imaging at high angular resolution: An overview using lossy compression
- Author
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C. Dollet, Albert Bijaoui, and Francois Mignard
- Subjects
Point spread function ,Physics ,business.industry ,media_common.quotation_subject ,Resolution (electron density) ,Astronomy and Astrophysics ,Astrometry ,Lossy compression ,Wavelet ,Optics ,Space and Planetary Science ,Sky ,Angular resolution ,business ,Image compression ,media_common ,Remote sensing - Abstract
We examine a possible extension of the Gaia mission in the form of a high-spatial resolution all-sky survey in the visible based on a scanning satellite and show that the main limitation is the amount of collected data to be transmitted. We then investigate the kind of image compression that would make it possible to carry out a complete cartography at a resolution of 0. 1, which would constitute a major advance in sky mapping. The most significant information is projected into wavelet space after the subtraction of the brighter objects that are mapped independently with the instrument point spread function and transmitted separately. The study is based on a Gaia-like instrument using a rectangular pupil and one-dimensional high resolution along scan. The difference of resolution across- and along-scan is compensated by the combination of all the observations at the end of the mission in Fourier space. A gain of 2-3 mag compared with the magnitude limit of the on-board detection could be achieved with the features of the Astro Sky Mapper of the Gaia mission.
- Published
- 2004
7. DeQuant: a flexible multiresolution restoration framework
- Author
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Albert Bijaoui and Ghada Jammal
- Subjects
business.industry ,Computer science ,Noise reduction ,Multiresolution analysis ,Process (computing) ,Pattern recognition ,Image processing ,Measure (mathematics) ,Wavelet ,Control and Systems Engineering ,Signal Processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Software ,Image restoration - Abstract
The contribution of this paper is to develop and analyze a new wavelet-based regularized restoration method for noise removal in photon limited imagery. This new framework presents the two main following advantages: (1) it assigns a new value to the non-significant wavelet coefficients which reduces artifacts and enables the incorporation of realistic prior information into the estimation process and (2) it is based on a local detection process with a measure of the significance of the detected structures. Its potential to improve nuclear medicine imaging is examined.
- Published
- 2004
8. Cardioventilatory changes induced by mentally imaged rowing
- Author
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Pascale Calabrese, Laurent Messonnier, André Eberhard, Eve Bijaoui, and Gila Benchetrit
- Subjects
Adult ,Male ,Aging ,medicine.medical_specialty ,Respiratory rate ,Sports medicine ,Physiology ,Physical Exertion ,Rowing ,Physical exercise ,Cognition ,Heart Rate ,Physiology (medical) ,Adaptation, Psychological ,Heart rate ,medicine ,Humans ,Orthopedics and Sports Medicine ,Ships ,biology ,Pulmonary Gas Exchange ,Athletes ,business.industry ,Respiration ,Age Factors ,Public Health, Environmental and Occupational Health ,Cardiorespiratory fitness ,General Medicine ,Middle Aged ,biology.organism_classification ,Adaptation, Physiological ,Imagination ,Breathing ,Physical therapy ,Female ,business ,Psychomotor Performance ,Sports - Abstract
Mentally imaged but unexecuted physical activity has been reported to induce a cardiorespiratory change. In order to test whether the previous experience of the performed exercise was a prerequisite to observe these changes, ventilation and heart rate were recorded during mental imagination of a rowing race in four groups of volunteers: 12 competitive rowers, 10 non-rower athletes, 12 students (22-30 years old) and 12 senior subjects (50-60 years old). Recordings were performed at rest, during the viewing of a rowing race and during mental imagination of this race. Analysis of variance revealed significant condition effect for all cardiorespiratory variables. All subjects increased their breathing rate (mean increase: 16 breaths.min(-1) in rowers, 8 breaths.min(-1) in athletes, 8 breaths.min(-1) in students, and 6 breaths.min(-1) in seniors), 29 decreased their tidal volume (mean decrease: 100 ml in rowers, 102 ml in athletes, 120 ml in students and 26 ml in seniors), with an increase in the resulting ventilation in 38 subjects (mean increase: 14 l.min(-1) in rowers, 3.6 l.min(-1) in athletes, 2.8 l.min(-1) in students, 2.6 l.min(-1) in seniors). Heart rate was increased in 34 subjects (mean increase: 12 beats.min(-1) in rowers, 5 beats.min(-1) in athletes, 6 beats.min(-1) in students and 5 beats.min(-1) in seniors). The number of subjects who exhibited changes was evenly distributed among the four groups. However, mean values of the changes were higher in rowers than in the three other groups, mainly due to three rowers who exhibited extremely large increases in cardioventilatory variables. Analysis of variance showed no significant group effect for heart rate and breathing rate. These results suggest that rowing experience may not be necessary for changes in heart rate and ventilation to be elicited by mentally imagining a rowing race.
- Published
- 2004
9. Mechanical Properties of the Lung and Upper Airways in Patients with Sleep-disordered Breathing
- Author
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Victoria Champagne, R. John Kimoff, Pierre Baconnier, Jason H. T. Bates, and Eve Bijaoui
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Adult ,Male ,Pulmonary and Respiratory Medicine ,Polysomnography ,Critical Care and Intensive Care Medicine ,Airway resistance ,Sleep and breathing ,Respiratory disturbance index ,Humans ,Medicine ,Lung ,Lung Compliance ,Sleep Apnea, Obstructive ,medicine.diagnostic_test ,business.industry ,Airway Resistance ,Middle Aged ,respiratory system ,medicine.disease ,Elasticity ,respiratory tract diseases ,Obstructive sleep apnea ,medicine.anatomical_structure ,Anesthesia ,Breathing ,Pharynx ,Pulmonary Ventilation ,business ,Hypopnea - Abstract
We studied the changes in lung and upper airway mechanics in adult human subjects with obstructive sleep apnea/hypopnea syndrome (OSAHS) during wakefulness, sleep, and at arousal from sleep. We used two numerical methods that we have previously developed specifically for dealing with inspiratory flow limitation during sleep: the modified Mead-Whittenberger method, and information-weighted histograms obtained using recursive least squares. Full polysomnography including esophageal pressure and airflow measurements was performed in seven men with OSAHS (respiratory disturbance index: 55.8 +/- 23.2 events/h). Pharyngeal pressure was recorded in four of the subjects to partition lung mechanics into its upper airway and lower lung components. Both techniques showed that total lung resistance and elastance increased significantly (p0.05) during obstructed breathing and that this increase was reversed at the end of the obstruction. The partitioning of mechanics showed that upper airway collapse was primarily responsible for the increase in lung resistance. Our results suggest that OSAHS may lead to transient abnormalities in the recruitment of lung units and the gas exchanging capacity of the lungs.
- Published
- 2002
10. Wavelets, Gaussian mixtures and Wiener filtering
- Author
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Albert Bijaoui
- Subjects
business.industry ,Noise reduction ,Gaussian ,Wiener filter ,Wiener deconvolution ,Wavelet transform ,Probability density function ,Pattern recognition ,Gaussian random field ,symbols.namesake ,Wavelet ,Control and Systems Engineering ,Signal Processing ,symbols ,Applied mathematics ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Software ,Mathematics - Abstract
In this short communication a non-linear Wiener filtering is obtained from a Bayesian approach of the probability density function modelled as a Gaussian mixture. Its application on the wavelet denoising leads to excellent results.
- Published
- 2002
11. Mechanical output impedance of the lung determined from cardiogenic oscillations
- Author
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Jason H. T. Bates, Eve Bijaoui, and Pierre Baconnier
- Subjects
Adult ,Male ,Glottis ,Physiology ,Physical Exertion ,Respiratory physiology ,Models, Biological ,Forced Oscillation Technique ,Functional residual capacity ,Airway resistance ,Heart Rate ,Reference Values ,Oscillometry ,Physiology (medical) ,Heart rate ,medicine ,Humans ,Output impedance ,Exercise ,Lung ,Fourier Analysis ,business.industry ,Airway Resistance ,Mechanical impedance ,Heart ,Mechanics ,Anatomy ,medicine.anatomical_structure ,Respiratory Mechanics ,Female ,business - Abstract
The beating heart naturally oscillates the lung because of the close juxtaposition between these organs producing cardiogenic oscillations in flow that can be measured at the mouth when the glottis is open. Correspondingly, if the mouth is occluded, the same phenomenon produces cardiogenic pressure oscillations that can be measured just distal to the site of occlusion. The Fourier-domain ratio of these oscillations in pressure and flow constitutes what we call cardiogenic respiratory impedance (Zc). We calculated Zc between about 1.5 and 10 Hz in relaxed normal subjects at functional residual capacity with open glottis. Zc was insensitive to heart rate changes induced by exercise and had an imaginary part close to zero at all frequencies investigated. Its real part was similar to or smaller than resistance determined by the forced oscillation technique. We speculate that Zc measures the flow resistance of the central and upper airways of the lung. Zc may be useful as a means of obtaining information about lung mechanics without the need for an external source of flow perturbations.
- Published
- 2001
12. [Untitled]
- Author
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A. Maucherat, B. Vandame, A. Bijaoui, F. Portier-Fozzani, and Eit Team
- Subjects
Physics ,business.industry ,Astronomy and Astrophysics ,Galaxy ,Wavelet ,Space and Planetary Science ,Histogram ,Physics::Space Physics ,Wide dynamic range ,Coronal mass ejection ,Calibration ,Astrophysics::Solar and Stellar Astrophysics ,Computer vision ,Artificial intelligence ,Noise (video) ,Zoom ,business ,Remote sensing - Abstract
The large dynamic range provided by the SOHO/EIT CCD (1 : 5000) is needed to observe the large EUV zoom of coronal structures from coronal homes up to flares. Histograms show that often a wide dynamic range is present in each image. Extracting hidden structures in the background level requires specific techniques such as the use of the Multiscale Vision Model (MVM, Bijaoui et al., 1998). This method, based on wavelet transformations optimizes detection of various size objects, however complex they may be. Bijaoui et al. built the Multiscale Vision Model to extract small dynamical structures from noise, mainly for studying galaxies. In this paper, we describe requirements for the use of this method with SOHO/EIT images (calibration, size of the image, dynamics of the subimage, etc.). Two different areas were studied revealing hidden structures: (1) classical coronal mass ejection (CME) formation and (2) a complex group of active regions with its evolution. The aim of this paper is to define carefully the constraints for this new method of imaging the solar corona with SOHO/EIT. Physical analysis derived from multi-wavelength observations will later complete these first results.
- Published
- 2001
13. Smoking habits of 411 women with histologically proven endometriosis and 567 unaffected women
- Author
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Carlos Souza, Bruno Borghese, Gérard Bijaoui, François Goffinet, Charlotte Ngo, Marie-Christine Lafay-Pillet, Dominique de Ziegler, and Charles Chapron
- Subjects
Adult ,medicine.medical_specialty ,Time Factors ,Adolescent ,Smoking habit ,media_common.quotation_subject ,Endometriosis ,Fertility ,Habits ,Young Adult ,Risk Factors ,medicine ,Humans ,Child ,media_common ,Uterine Diseases ,Gynecology ,Obstetrics ,business.industry ,Deep endometriosis ,Smoking ,Obstetrics and Gynecology ,medicine.disease ,Deep infiltrating endometriosis ,Reproductive Medicine ,Case-Control Studies ,Female ,business - Abstract
Smoking habits did not influence either the risk of any form of endometriosis (superficial peritoneal endometriosis, ovarian endometriomas, and deep infiltrating endometriosis) and did not correlate with the revised American Fertility Society stages or scores.
- Published
- 2010
14. A combined approach for object detection and deconvolution
- Author
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Albert Bijaoui, I. Valtchanov, Fionn Murtagh, and Jean-Luc Starck
- Subjects
Physics ,Point spread function ,Blind deconvolution ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,General Physics and Astronomy ,Wavelet transform ,Pattern recognition ,Astrophysics ,Object (computer science) ,Object detection ,Image (mathematics) ,Range (mathematics) ,Deconvolution ,Artificial intelligence ,business - Abstract
The Multiscale Vision Model is a recent object detection method, based on the wavelet transform. It al- lows us to extract all objects contained in an image, what- ever their size or their shape. From each extracted object, information concerning flux or shape can easily be deter- mined. We show that such an approach can be combined with deconvolution, leading to the reconstruction of de- convolved objects. We discuss the advantages of this ap- proach, such as how we can perform deconvolution with a space-variant point spread function. We present a range of examples and applications, in the framework of the ISO, XMM and other projects, to illustrate the eectiveness of this approach.
- Published
- 2000
15. Developmental factors of urethral human papillomavirus lesions: correlation with circumcision
- Author
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J. M. Casanova, D Piron, Bijaoui G, and Aynaud O
- Subjects
Gynecology ,Sexually transmitted disease ,medicine.medical_specialty ,biology ,business.industry ,Urology ,HPV infection ,virus diseases ,medicine.disease ,biology.organism_classification ,medicine.disease_cause ,female genital diseases and pregnancy complications ,Squamous metaplasia ,Urethra ,medicine.anatomical_structure ,medicine ,Urethritis ,Sex organ ,Papillomaviridae ,Chlamydia trachomatis ,business - Abstract
Objective To assess the relationship between circumcision and urethral human papillomavirus (HPV) lesions, and the influence of urethritis on the development of urethral HPV infections on inducing squamous metaplasia of the urethral epithelium. Patients and methods The study included 210 heterosexual, HIV-negative men (median age 29 years) who all had female partners with genital HPV infection. The patients were divided into three groups according to clinical findings, i.e. 97 patients with no clinical HPV lesions on peniscopy and urethroscopy, 70 patients with balanopreputial lesions but no urethral lesions, and 43 patients with urethral HPV lesions, including 17 who had associated penile lesions. They all underwent meatopeniscopy for HPV screening, urethral biopsy for histological analysis, and bacterial cultures were taken. The results in each subgroup were compared between circumcised and uncircumcised men. Results There was no significant difference in the incidence of HPV infection (58% vs 42%, odds ratio, OR, 1.8; 95% confidence interval, CI, 0.98–3.62) between uncircumcised and circumcised men, but this relationship differed with the developmental site of HPV lesions (shaft-foreskin, P
- Published
- 1999
16. Estimating respiratory mechanics in the presence of flow limitation
- Author
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John E. Remmers, Stephanie A. Tuck, Eve Bijaoui, and Jason H. T. Bates
- Subjects
Male ,medicine.medical_specialty ,Swine ,Physiology ,Respiratory physiology ,Models, Biological ,Physiology (medical) ,Internal medicine ,medicine ,Animals ,Obesity ,Respiratory system ,Intensive care medicine ,Air Pressure ,business.industry ,Respiratory disease ,Linear model ,Apnea ,Sleep apnea ,medicine.disease ,Elasticity ,Obstructive sleep apnea ,Respiratory Mechanics ,Cardiology ,Pleura ,medicine.symptom ,business ,Airway ,Algorithms - Abstract
Dynamic collapse of the pulmonary airways, leading to flow limitation, is a significant event in a number of respiratory pathologies, including obstructive sleep apnea syndrome and chronic obstructive pulmonary disease. Quantitative evaluation of the mechanical status of the respiratory system in these conditions provides useful insights into airway caliber and tissue stiffness, which are hallmarks of such abnormalities. However, assessing respiratory mechanics in the presence of flow limitation is problematic because the single-compartment linear model on which most assessment methods are based is not valid over the entire breath. Indeed, even deciding which parts of a breath are flow limited from measurement of mouth flow and pleural pressure often proves to be difficult. In this study, we investigated the use of two approaches to assessing the overall mechanical properties of the respiratory system in the presence of inspiratory flow limitation. The first method is an adaptation of the classic Mead-Whittenberger method, and the second method is based on information-weighted histograms obtained from recursively estimated signals of respiratory resistance and elastance. We tested the methods on data simulated by using a computer model of the respiratory system and on data collected from obese sleeping pigs. We found that the information-weighted histograms provided the more robust overall estimates of respiratory mechanics.
- Published
- 1999
17. Detection of objects near the geostationary ring using a CCD camera
- Author
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P. Oberti, B. Vandame, F. Alby, A. Bijaoui, J.C. Venturino, and A. Maury
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Atmospheric Science ,Computer science ,business.industry ,Frame (networking) ,Aerospace Engineering ,Astronomy and Astrophysics ,Schmidt camera ,law.invention ,Telescope ,Geophysics ,Software ,Space and Planetary Science ,law ,Limiting magnitude ,Geostationary orbit ,General Earth and Planetary Sciences ,Noise (video) ,business ,Focus (optics) ,Remote sensing - Abstract
A collaboration between the Observatoire de la Cote d'Azur (OCA) and the Centre National d'Etudes Spatiales (CNES) started in 1996 for detecting optically faint sources close to the geostationary ring using the OCA Schmidt camera. After a first approach based on photographic films we have installed a 2048 × 2048 CCD camera at the focus of the telescope. An automated analysis method was developed. After identifying all stellar trails on the CCD frames we substract them after a suitable modelization. The detection of the remaining objects takes into account the noise variations due to the model defects. For each CCD frame about two hundred point-like objects are identified. The detection of possible space objects is achieved by matching the lists of candidates obtained on three or more successive images. Few objects are observed at a limiting magnitude around 20. We determine their approximate orbits in order to allow follow up observations for each object. A software allowing the user to process the images just after the acquisition has been developed. A one year observational campaign is foreseen in the near future.
- Published
- 1999
18. La correction du débit en présence d’une fuite entre trachée et sonde endotrachéale
- Author
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Pierre Baconnier, P Andrini, A Eberhard, E Bijaoui, Carry Py, and J. P. Perdrix
- Subjects
medicine.medical_specialty ,Adult patients ,business.industry ,General Medicine ,Infant newborn ,Surgery ,Anesthesiology and Pain Medicine ,Simulated data ,Recien nacido ,Anesthesia ,medicine ,Respiratory cycle ,Positive-Pressure Respiration ,Nuclear medicine ,business ,Positive end-expiratory pressure ,Endotracheal tube - Abstract
Presenter une methode d’estimation de la fuite entre trachee et sonde endotracheale chez le nouveau-ne afin de compenser l’erreur sur la mesure du debit et de surveiller les caracteristiques mecaniques respiratoires par l’analyse des signaux de debit et de pression mesures a l’origine de la sonde. On suppose la resistance de fuite (Rf) constante sur un cycle et on mesure les caractenstiques resistives du tube endotracheal. La methode a ete validee avec un modele mecanique de poumon et appliquee aux enregistrements de trois nouveau-nes prematures admis en reanimation neonatale pour des detresses respiratoires. Une methode des moindres carres a permis d’estimer, avant et apres correction du debit, la pression positive de fin d’expiration (PEEP). Pour les simulations, l’estimation deRf concorde avec la mesure directe. En clinique, l’efficacite de la correction est demontree: le debit corrige revient a zero pendant la pause de fin d’inspiration. En simulation, avant correction du debit, la PEEP est sous-estimee de 10 a 20 cm H2O, alors qu’apres correction l’erreur est inferieure a 2 cm H2O. En clinique, la PEEP estimee passe de valeurs negatives (−0,3 ± 1,3 cm H2O avant correction) a des valeurs positives (3.6 ± 0,7 cm H2O apres correction) superieures a la PEEP imposee (2 cm H2O). L’efficacite de cette methode simple a ete demontree. Elle pourrait etre utilisee avec profit sur des patients adultes, la correction sur le debit n’etant pas effectuee en l’absence de fuite. To estimate the leak between the endotracheal tube and the trachea in newborns in order to compensate for errors in airflow measurement and to monitor mechanical variables from pressure and flow signals. Assuming that the leak resistance (Rf) is constant during a respiratory cycle, the resistive properties of the endotracheal tube were evaluated. The method was validated in the intensive care unit with a mechanical test lung and assessed on recordings of three newboms during mechanical ventilation for RDS. We have used a least squares method for the estimation of positive end expiratory pressure (PEEP) on both newborns and simulated data. Direct measurements of simulated leak resistances on the mechanical lung are in agreement with our estimation of leak resistances. In newboms. the success of flow correction is evidenced on end inspiratory pauses: corrected flow drops to zero while raw data show a constant nonzero flow. On the simulated lung, the PEEP underestimation with uncorrected flow ranges from 10 to 20 cm H2O while the corresponding underestimation with corrected flow is less than 2 cm H2O. In newboms, the flow correction shifts the estimated PEEP from negative values (-0.3 ± 1.3 cm H2O before correction) to positive values (3.6 ± 0.7 cm H2O after correction) higher than the imposed PEEP (2 cm H2O). The efficiency of this simple method has been demonstrated. It could be used successfully on adult patients, as there will not be flow correction in the absence of leaks.
- Published
- 1997
19. A Multiscale Vision Model to Analyse Field Astronomical Images
- Author
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Albert Bijaoui and Frédéric Rué
- Subjects
Pixel ,Computer science ,business.industry ,Connectivity graph ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Wavelet transform ,Astronomy and Astrophysics ,Real image ,Space and Planetary Science ,Computer Science::Computer Vision and Pattern Recognition ,Conjugate gradient method ,Graph (abstract data type) ,Computer vision ,Discrete transform ,Artificial intelligence ,business ,Image restoration - Abstract
We have implemented a multiscale vision model based on the wavelet transform to analyse field astronomical images. The discrete transform is performed by the a trous algorithm. The vision model is based on the notion of significant structures. We identify the pixels of the associated wavelet transform space (WTS) with the objects. For each scale a region labelling is carried out. An interscale connectivity graph is then established. In accordance with some rules that permit false detections to be removed, the objects and their sub-objects are identified. They define respectively trees and sub-trees in the graph. In this way, the identification of the WTS pixels of the tree related to a given object leads to the reconstruction of its image by the conjugate gradient method. The model has been tested successfully on simulated images of stars and galaxies which allow us to show the capabilities of the detection and restoration procedures of the model. Finally, tests on real images show that one can analyse complex structures better than with classical astronomical vision models.
- Published
- 1997
20. Multiscale image fusion in astronomy
- Author
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Yves Bobichon, Benoit Vandame, and Albert Bijaoui
- Subjects
Image fusion ,Computer science ,business.industry ,Computer Science::Computer Vision and Pattern Recognition ,Compression (functional analysis) ,Astronomy and Astrophysics ,Computer vision ,Sensitivity (control systems) ,Artificial intelligence ,business ,Remote sensing - Abstract
Image fusion techniques are increasingly applied to astronomical images in order to improve sensitivity or to compare images. We discuss in this paper the ability of multiscale transforms for many applications: geometrical and photometrical registrations, co-addition and compression. A strategy for multiscale image fusion is derived.
- Published
- 1997
21. A multiscale vision model applied to astronomical images
- Author
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Frédéric Rué and Albert Bijaoui
- Subjects
Pixel ,Computer science ,business.industry ,Stationary wavelet transform ,Connectivity graph ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Wavelet transform ,Astronomy and Astrophysics ,Pattern recognition ,Computer Science::Computer Vision and Pattern Recognition ,Conjugate gradient method ,Graph (abstract data type) ,Discrete transform ,Artificial intelligence ,business ,Continuous wavelet transform - Abstract
We have implemented a multiscale vision model based on the wavelet transform to analyse field astronomical images. The discrete transform is performed by the a trous algorithm. The vision model is based on the notion of the significant structures. We identify the pixels of the wavelet transform space (WTS) associated with the objects. At each scale a region labelling is carried out. An interscale connectivity graph is then established. In accordance with some rules that permit false detections to be removed, the objects and their sub-objects are identified. They define respectively trees and sub-trees in the graph. So, the identification of the WTS pixels of the tree related to a given object leads to the reconstruction of its image by the conjugate gradient method. The model has been tested successfully on astronomical images which shows that complex structures are better analysed than using usual astronomical vision models.
- Published
- 1996
22. A multiscale vision model adapted to the astronomical images
- Author
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Frédéric Rué and Albert Bijaoui
- Subjects
business.industry ,Stationary wavelet transform ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Wavelet transform ,Cascade algorithm ,Image processing ,Wavelet packet decomposition ,Wavelet ,Control and Systems Engineering ,Signal Processing ,Graph (abstract data type) ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Software ,Image restoration ,Mathematics - Abstract
The analysis of the sky shows many kinds of hierarchically distributed objects. We have introduced a multiscale vision model based on the wavelet transform. The discrete transform is performed by the a trous algorithm which furnishes an isotropic vision, with a unique wavelet function. The vision model is based on the notion of the significant structures. We identify the pixels of the wavelet transform space (WTS) we can attribute to the objects. At each scale a region labelling is done. An interscale connectivity graph is then established. Connected trees are identified from the preceding graph. An object is generally associated to a subtree built from this graph. The identification of WTS pixels related to a given object leads to reconstructing an image by partial restoration algorithms. The object properties are extracted from the restored image. The main difficulty lies in the object reconstruction knowing the wavelet coefficients in the volume where the object is defined. It is a classical inverse problem. We choose to solve it using iterative algorithms. These algorithms give correct restored images, as we show on different examples, without or with adding a Gaussian noise. The influence of close objects can be partially removed.
- Published
- 1995
23. Multiresolution Support Applied to Image Filtering and Restoration
- Author
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Jean-Luc Starck, Fionn Murtagh, and Albert Bijaoui
- Subjects
Sequence ,Pixel ,Iterative method ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Context (language use) ,Resolution (logic) ,Computer Graphics and Computer-Aided Design ,Image (mathematics) ,Range (mathematics) ,Computer Science::Computer Vision and Pattern Recognition ,Modeling and Simulation ,Computer Science::Multimedia ,Computer vision ,Geometry and Topology ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Image restoration ,ComputingMethodologies_COMPUTERGRAPHICS ,Mathematics - Abstract
The notion of a multiresolution support is introduced. This is a sequence of Boolean images related to significant pixels at each of a number of resolution levels. The multiresolution support is then used for noise suppression, in the context of image filtering, or iterative image restoration. Algorithmic details, and a range of practical examples, illustrate this approach.
- Published
- 1995
24. Multiresolution in astronomical image processing: A general framework
- Author
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Jean-Luc Starck, Fionn Murtagh, and Albert Bijaoui
- Subjects
Astronomical Objects ,business.industry ,Computer science ,Astrophysics::Instrumentation and Methods for Astrophysics ,Wavelet transform ,Image processing ,Object detection ,Electronic, Optical and Magnetic Materials ,Computer Science::Computer Vision and Pattern Recognition ,Digital image processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Software ,Image restoration ,Image compression ,Feature detection (computer vision) - Abstract
Multiresolution transforms, including a wavelet transform, are applied simage visualization, image restoration, filtering and compression, × object detection. Variance stabilization is used, when appropriate, cater for common astronomical image noise models. We discuss idation of such methods in the case of astronomical image processing. A range of examples illustrate the effectiveness of this aproach in handling point source and extended astronomical objects.
- Published
- 1995
25. In women with endometriosis anti-Müllerian hormone levels are decreased only in those with previous endometrioma surgery
- Author
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Vanessa Gayet, Gérard Bijaoui, Dominique de Ziegler, Charles Chapron, Isabelle Streuli, Jacques de Mouzon, and Pietro Santulli
- Subjects
Infertility ,Adult ,Anti-Mullerian Hormone ,Reoperation ,medicine.medical_specialty ,Paris ,Cross-sectional study ,Statistics as Topic ,Endometriosis ,Down-Regulation ,Severity of Illness Index ,Hospitals, University ,Recurrence ,Surveys and Questionnaires ,Medicine ,Humans ,Prospective Studies ,Prospective cohort study ,Ovarian reserve ,Gynecology ,Univariate analysis ,biology ,business.industry ,Rehabilitation ,Age Factors ,Obstetrics and Gynecology ,Anti-Müllerian hormone ,Odds ratio ,medicine.disease ,Surgery ,Cross-Sectional Studies ,Reproductive Medicine ,biology.protein ,Female ,business ,Infertility, Female - Abstract
STUDY QUESTION Are anti-Mullerian hormone (AMH) levels lower in women with endometriosis, notably those with endometriomas (OMAs) and deep infiltrating lesions, compared with controls without endometriosis? SUMMARY ANSWER Endometriosis and OMAs per se do not result in lower AMH levels. AMH levels are decreased in women with previous OMA surgery independently of the presence of current OMAs. WHAT IS KNOWN ALREADY The impact of endometriosis and OMAs per se on the ovarian reserve is controversial. Most previous studies have been conducted in infertile women. The strength of our study lies in the following points: (i) the selection of women undergoing surgery and not only according to the presence of infertility, (ii) the classification of women with endometriosis and controls based on strict surgical and histological criteria. STUDY DESIGN, SIZE, DURATION Cross-sectional study using data prospectively collected in all non-pregnant
- Published
- 2012
26. From necessity to business entrepreneurship: The case of the Songhai center, Porto Novo, Benin
- Author
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Ilan Bijaoui
- Subjects
Typology ,Entrepreneurship ,Need for affiliation ,business.industry ,Need for achievement ,Order (business) ,Need for power ,General Earth and Planetary Sciences ,Center (algebra and category theory) ,Sociology ,Marketing ,Human resources ,business ,General Environmental Science - Abstract
The “push theory" maintains that individuals are pushed into entrepreneurship by negative external forces. The resulting activity is referred to as necessity entrepreneurship. The “pull theory” contends that individuals are attracted to entrepreneurial activities because they seek self-fulfillment resulting in business or opportunity entrepreneurship. In the present study we used the McClelland's typology of business/opportunity entrepreneurship: "need for achievement," "need for affiliation," and "need for power", in order to analyze the entrepreneurship capabilities of Songhai's students participating to the 18-month training program. We identify the entrepreneurial intentions and interests required to differentiate between entrepreneurs at the necessity level and those at McClelland's "need for achievement," "need for affiliation," or "need for power" levels of business entrepreneurship. According to the McClelland's typology, most Songhai students are potential business entrepreneurs in "need for achievement," and in "need for affiliation" level. Key words: Necessity entrepreneurship, business entrepreneurship, Africa, motivation, cooperation, leadership.
- Published
- 2012
27. Parameter estimation from a model grid application to the Gaia RVS spectra
- Author
-
C. Ordenovic, Albert Bijaoui, Alejandra Recio-Blanco, P. de Laverny, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Statistics and Probability ,Estimation theory ,business.industry ,Decision tree learning ,Decision tree ,Oblique case ,Grid ,computer.software_genre ,01 natural sciences ,Sample (graphics) ,010104 statistics & probability ,Software ,0103 physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Data mining ,0101 mathematics ,business ,010303 astronomy & astrophysics ,computer ,Selection (genetic algorithm) ,ComputingMilieux_MISCELLANEOUS ,Mathematics - Abstract
In the framework of the ESA Gaia mission, stellar atmospheric parameters will be extracted for millions of spectra that will be observed by Gaia RVS (Wilkinson et al. 2005) [21] . Due to this high number of observed spectra it is necessary that the analysis be carried out using fast and robust automated algorithms. In this paper, we analyze the efficiency of a selection of fitting algorithms in obtaining stellar parameters for a sample of spectra. Several of these algorithms are based on the use of a decision tree, either oblique, kd or decorated. The tests are carried out using the same model grid in the same software environment. Different performance indices associated with our scientific goal are examined. The application of the Gauss–Newton algorithm initialized using a decision tree algorithm appeared to best satisfy the performance criteria.
- Published
- 2012
28. Filtering and deconvolution by the wavelet transform
- Author
-
Jean-Luc Starck and Albert Bijaoui
- Subjects
Discrete wavelet transform ,Lifting scheme ,business.industry ,Second-generation wavelet transform ,Stationary wavelet transform ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Wavelet transform ,Wavelet packet decomposition ,Wavelet ,Control and Systems Engineering ,Signal Processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,Harmonic wavelet transform ,business ,Algorithm ,Software ,Mathematics - Abstract
The wavelet transform gives information in both spatial and frequency domains and is a very useful tool for describing the hierarchical structures. A new approach for filtering based on the wavelet transform is presented in this paper, and several algorithms are proposed. A criterion of quality, which takes into account the resolution, is used to compare these algorithms. We show that deconvolution can be done using filtered wavelet coefficients. By computing the wavelet from the point spread function, we find a new transform algorithm and a reconstruction method related to it.
- Published
- 1994
29. Common mistakes, negligence and legal offences in paediatric dentistry: a self-report
- Author
-
M. Gordon, S. Blumer, M. Ashkenazi, and E. Bijaoui
- Subjects
Anamnesis ,education.field_of_study ,Medical Errors ,business.industry ,Sedation ,Population ,Malpractice ,Dentistry ,Paediatric dentistry ,stomatognathic diseases ,stomatognathic system ,Swallowing ,Pediatric Dentistry ,Accidental ,Pediatrics, Perinatology and Child Health ,medicine ,Humans ,Dentistry (miscellaneous) ,Self Report ,Parental consent ,medicine.symptom ,Israel ,business ,education - Abstract
AIM: To identify the type and relative prevalence of mistakes, negligence and legal offences (MNLOs) performed or nearly performed by paediatric dentists during their entire career. METHODS: The population consisted of 25 (29.4%) certified and 48 (56.5%) non-certified paediatric dentists, and 12 (14.1%) residents in paediatric dentistry. A structured anonymous questionnaire accessed occupational characteristics and frequencies of MNLOs (0, 1–4, 5–10, >10). RESULTS: The most prevalent MNLOs related to the performance of radiographs: bite-wings with overlapping teeth (90%), overturned film (30%), film over-exposure (48%), faulty film development (84%) and exposure of the same side of film twice (32%). Other MNLOs were drilling an intact tooth (37%), misdiagnosing existing radiographic caries (63%), anaesthetising the wrong tooth (49%), accidental incision of the cheek/lips during treatment (73%), administering an incorrect dose of antibiotic (49%) or analgesics (24%), extracting the wrong tooth (15%), documenting the wrong tooth in the patient’s file (63%), and a child swallowing an instrument (33%) or clasp (15%). Prevalent MNLOs included administering sedation to a child who had not fasted (32%), sedating without monitoring (9%), treating children without receiving signed parental consent (15%) and losing a radiograph (64%). CONCLUSIONS: MNLOs occur commonly during various operative dental treatments. Means to raise awareness and to implement regulations should be addressed to limit these mistakes.
- Published
- 2011
30. Oral contraceptives and endometriosis: the past use of oral contraceptives for treating severe primary dysmenorrhea is associated with endometriosis, especially deep infiltrating endometriosis
- Author
-
Bruno Borghese, Dominique de Ziegler, Carlos Souza, Charles Chapron, Marie-Christine Lafay-Pillet, Pietro Santulli, Gérard Bijaoui, and François Goffinet
- Subjects
Adult ,medicine.medical_specialty ,Cross-sectional study ,media_common.quotation_subject ,Endometriosis ,Fertility ,Dysmenorrhea ,Risk Factors ,medicine ,Humans ,Stage (cooking) ,media_common ,Gynecology ,business.industry ,Incidence (epidemiology) ,Rehabilitation ,Obstetrics and Gynecology ,medicine.disease ,Deep infiltrating endometriosis ,Confidence interval ,Contraceptives, Oral, Combined ,Cross-Sectional Studies ,Reproductive Medicine ,Family planning ,Female ,business ,Contraceptives, Oral - Abstract
BACKGROUND: The relationship between the use of oral contraception (OC) and endometriosis remains controversial. We therefore compared various characteristics of OC use and the surgical diagnosis of endometriosis histologically graded as superficial peritoneal endometriosis (SUP) ovarian endometrioma (OMA) or deep infiltrating endometriosis (DIE). METHODS: This cross-sectional study included 566 patients without visible endometriosis at surgery as controls and 410 patients with histologically proven endometriosis categorized by their worst lesions as SUP n = 47 OMA n = 120 and DIE n = 243. Personal data including on OC use were prospectively collected during standardized interviews. Statistical analysis was performed using unconditional logistic regression. RESULTS: Past OC users had an increased incidence of endometriosis (adjusted odd ratios (OR) = 2.79 95% confidence interval (CI) 1.74-5.12 P = 0.002) of any revised American Fertility Society stage. Women who had previously used OC for severe primary dysmenorrhea were even more frequently diagnosed with endometriosis (adjusted OR = 5.6 95% CI 3.2-9.8) especially for DIE (adjusted OR = 16.2 95% CI 7.8-35.3). Women who had previously used OC for other reasons also had an increased risk of endometriosis but to a lesser extent (adjusted OR = 2.6 95% CI 1.8-4.1). The age at which OC was initiated duration of OC use and free interval from last OC use were not significantly different between control and endometriosis women irrespective of histological grading. Current OC users did not show an increased prevalence of endometriosis (OR = 1.22 95% CI 0.6-2.52). CONCLUSIONS: Our data indicate that a history of OC use for severe primary dysmenorrhea is associated with surgical diagnosis of endometriosis especially DIE later in life. However this does not necessarily mean that use of OC increases the risk of developing endometriosis. Past use of OC for primary dysmenorrhea may serve as a marker for women with endometriosis and DIE.
- Published
- 2011
31. Clinical uses of anti-Müllerian hormone assays: pitfalls and promises
- Author
-
Timothée Fraisse, Dominique de Ziegler, Charles Chapron, Paul Bischof, Isabelle Streuli, and Gérard Bijaoui
- Subjects
Anti-Mullerian Hormone ,Ovulation ,Adult ,medicine.medical_specialty ,endocrine system ,media_common.quotation_subject ,Population ,Physiology ,Ovulation/physiology ,Reference Values ,Medicine ,Humans ,Longitudinal Studies ,Prospective Studies ,Prospective cohort study ,education ,Menstrual cycle ,Menstrual Cycle ,media_common ,Gynecology ,Immunoassay ,education.field_of_study ,ddc:618 ,biology ,business.industry ,urogenital system ,Anti-Mullerian Hormone/blood ,Obstetrics and Gynecology ,Reproducibility of Results ,Anti-Müllerian hormone ,University hospital ,Reproductive Medicine ,Prospective trial ,Menstrual Cycle/physiology ,biology.protein ,Regression Analysis ,Female ,Analysis of variance ,business - Abstract
Objective To investigate whether the controversy about fluctuations of anti-Mullerian hormone (AMH) levels during the menstrual cycle results from differences between the immunoassays currently available: the Beckman Coulter Immunotech kit (Fullerton, CA) and the Diagnostic Systems Laboratories kit (Webster, TX). Design Prospective trial. Setting Fertility clinics of two tertiary university hospitals. Patient(s) One hundred sixty-eight blood samples from three different populations. Serial samples at set intervals from the LH surge were taken in a fourth population of 10 volunteers. Intervention(s) We remeasured AMH levels by using the Diagnostic Systems Laboratories kit in 168 blood samples in which AMH initially had been measured by using the Beckman Coulter assay. We also conducted serial AMH measurements (n = 7) during the menstrual cycle of 10 women. Main Outcome Measure(s) Linear regression of AMH levels determined by using 2 different assays and analysis of variance of serial measurements in the menstrual cycle. Result(s) We found a linear relationship between the 2 methods, with a correlation coefficient of 0.88. When repeated individual AMH measures were longitudinally analyzed in relation to the LH surge, a slight but significant decrease was observed after ovulation. Conclusion(s) Differences in AMH fluctuations during the menstrual cycle reported in recent publications do not result from the use of different AMH assays. The changes in AMH levels after ovulation are slight, yet statistically significant. However, the fluctuations observed are smaller than intercycle variability and therefore are not clinically relevant as far as AMH measurements for clinical purposes are concerned. In daily practice, AMH therefore can be measured anytime during the menstrual cycle.
- Published
- 2009
32. An efficient image compression algorithm without distortion
- Author
-
A. Bijaoui and L. Huang
- Subjects
Lossless compression ,Texture compression ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,Data compression ratio ,Data_CODINGANDINFORMATIONTHEORY ,Artificial Intelligence ,Computer Science::Computer Vision and Pattern Recognition ,Distortion ,Signal Processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Software ,Image compression ,Data compression - Abstract
Huang, L. and A. Bijaoui. An efficient image compression algorithm without distortion, Pattern Recognition Letters 12 (1991) 69–72. We present in this paper an efficient image compression algorithm without distortion. It is based on a special iterative central prediction method with a hierarchic 4-bit code. By applying this method to some hydrodynamic simulation images, high compression ratios have been obtained.
- Published
- 1991
33. Wavelets and the analysis of astronomical objects
- Author
-
Albert Bijaoui and A. Fresnel
- Subjects
Astronomical Objects ,Wavelet ,Continuous wavelet ,Computer science ,business.industry ,Frequency domain ,Molecular cloud ,Computer vision ,Artificial intelligence ,business - Published
- 2008
34. Knowledge based classification of galaxies
- Author
-
Albert Bijaoui and Monique Thonnat
- Subjects
Structure (mathematical logic) ,Point (typography) ,business.industry ,Computer science ,Process (computing) ,Image processing ,Pattern recognition ,computer.software_genre ,Expert system ,Task (project management) ,Elliptical galaxy ,Multiplication ,Artificial intelligence ,business ,computer - Abstract
We have seen that the classification of galaxies is a very complex task but that it is not impossible to automate it. This can be useful both to objectively process large sets of data and to centralize and structure different kinds of expertise (in image processing, observation and classification); this last point becomes crucial with the multiplication of sensors used and the consequent difficulty of performing multisensor analysis.
- Published
- 2008
35. Storage Technologies
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
Engineering ,Network-attached storage ,business.industry ,Information repository ,Computer security ,computer.software_genre ,Object storage ,Storage area network ,Fibre Channel ,Windows Server ,Server ,Converged storage ,business ,computer ,Computer network - Abstract
Publisher Summary This chapter reviews the major storage technologies that can be used with Microsoft Exchange. When building any Exchange 2007 server, one should determine how much space must be planned for hosting the user mailboxes and optionally, shared information (public folders). In short, one will have to build storage solutions that implement to various degrees the attributes of capacity, availability, performance, manageability, and cost (affordability). The chapter discusses three key storage technologies and their relevance to Exchange 2007 including Direct-Attached Storage, Storage Area Networks (SANs), and Network Attached Storage (NAS). Direct-Attached Storage deals with local disks in servers. The networking and high-performance interfaces still do not allow building diskless servers for all solutions. Built using a standardized protocol, Fiber Channel, SANs are designed for high-performance block-mode access to raw devices. SAN-attached devices have no concept of file systems, a notion that remains at the operating system. After being placed in complex and high-end infrastructures, SAN are now making their way into the smaller small and medium business (SMB) market. Much of the upcoming challenge of the storage industry is to propose simple ways of managing relatively complex storage components. The NAS fundamental is the utilization of a data network protocol, IP (and more precisely, TCP/IP) to a file-share protocol. NAS made its way from file-sharing appliances, which rapidly evolved into mature storage components. Each of these storage approaches has pros and cons, all of which depend on the objectives one is pursuing, the revision of Microsoft Exchange and Windows Server that one intends to use, and his or her operating model.
- Published
- 2008
36. Performance Monitoring and Analysis
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
Engineering ,business.industry ,Troubleshooting ,computer.software_genre ,Toolbox ,System monitor ,Megabyte ,Windows Server ,Scripting language ,Performance engineering ,Operating system ,Iometer ,business ,computer - Abstract
Publisher Summary This chapter presents a methodology to process and turn out something meaningful from several hundred megabytes of information captured during performance analysis. The performance monitor in Windows comes with three basic features: the capture of performance counters capture into log files; trace information gathering; alert generation based on counter threshold, which can be utilized for triggering additional performance information. Performance monitoring in Windows Server has evolved from the performance monitor to include new tools such as a system monitor, which displays current or saved performance counters information; performance logs and alerts, which capture counter values and manage log files and alerts; and reliability and performance monitor in Vista and Windows Server 2008. The GUI for viewing performance counters is now provided as part of the System Monitor, another MMC snap-in, that can display either current system information or information captured by means of the performance log files. The System Monitor can be invoked by issuing the DOS command PERFMON. The performance analysis engineer typically has a toolbox that contains a series of tools and scripts, Excel sheets, and homegrown processes that facilitate making rapid performance analyses. To be efficient in finding needles in haystacks, or pinpointing a painful area in hours instead of weeks, the performance engineer for Exchange should be proficient in tools including Perfmon, Relog, Typeperf, Microsoft Excel, Charting and analysis tool, Sysinternals Process Monitor, Iometer, and Microsoft Exchange Performance Troubleshooting Analyzer. The basic performance counters that can be obtained using PERFMON in Windows 2003 are described.
- Published
- 2008
37. Basic Concepts of I/O Systems
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
business.industry ,Computer science ,Nearline storage ,RAID ,Storage virtualization ,computer.software_genre ,law.invention ,Object storage ,Storage area network ,Direct-attached storage ,law ,Converged storage ,Logical volume management ,Data_FILES ,Operating system ,business ,computer ,Computer hardware - Abstract
Publisher Summary This chapter provides information on key storage terminology and concepts related to Microsoft Exchange 2007. The goal of storage in any kind of computing environment is to have a place where data can be kept at rest. Data storing can be done randomly or sequentially. The mass media (disks and tapes) on which data is stored varies depending on the density, speed, and frequency of access. The chapter defines several terms related to data storage including capacity measurement unit Gigabyte (GB), data rate measurement unit Megabyte per second (MB/s), request rate measurement unit I/O per second (IOPS), and response time. For Exchange 2007, one needs to provide online storage that is reliable and fast. The storage speed for Microsoft Exchange depends on the activity one performs on the server. For regular online access to email, one needs to have a good I/O throughput (request rate). The size of the I/O is typically that of a database page, set to 8 KB with Exchange 2007 (with previous version of Microsoft Exchange, this was 4 KB). It is required to connect CPU (or CPUs) to disks by the means of storage controller, because a CPU accesses data directly from RAM, but certainly not directly to disk. RAID, used for redundant array of independent disks, is a technique that combines several independent disk drives into a single logical volume. RAID comes in many levels, with the base levels ranging from 0 to 5. Some storage controllers implement virtualization, which can be implemented at various levels including disk level, controller level, and network. Storage networks are inevitable in large enterprises to share the benefits of a strong storage environment among different servers (or storage consumers). Storage networks typically come in two modes: file-level access and block-level access.
- Published
- 2008
38. Storage Design Validation
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
Computer science ,business.industry ,Firmware ,Solution architecture ,Disk array ,Workload ,computer.software_genre ,Embedded system ,Server ,Latency (engineering) ,Iometer ,business ,computer ,Design Validation - Abstract
Publisher Summary A proof-of-concept phase should be included in a Microsoft Exchange project schedule. This testing phase allows verifying whether the theoretical assumptions were valid and the proposed solution architecture will meet own or customer's requirements. Several tools are available to test the configuration, starting from low level disk exercisers like IOmeter, to an Exchange Store process simulator, and at the upper end a tool that simulates the actions users perform when they read and send emails or meeting requests. Start the design validation by testing the storage environment before running a test that simulates users accessing the Exchange environment using Outlook Anywhere via ISA arrays and hardware load balancers. One should check to see whether the firmware and device drivers of the components used by Exchange servers are reliably working together. It is recommended to run tests in a test environment and not in a production environment. Separating the test environment from the production environment removes the risks that tests impact production systems. Low-level tools such as disk exercisers do not require a lot of prerequisites; full installation of the Exchange environment is not necessary—it is sufficient that the storage subsystem is connected to a Windows host. Therefore, they can be easily used to get results in a short timeframe. The IOmeter tool measures performance of network I/O and I/O to a disk subsystem. The tool allows one to characterize disk subsystem performance without the need to set up the complete infrastructure that the application requires. Regarding an Exchange mailbox server, one needs the server and the storage array, but does not need the Active Directory (AD) and the other Exchange server roles to verify disk array performance. Microsoft Exchange Server JetStress simulates disk I/O that the Exchange Store process performs. With JetStress one can check whether the system configuration will likely be able to handle the transactional workload generated by user activity with acceptable latency figures.
- Published
- 2008
39. Windows Storage
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
Windows Vista ,Computer science ,business.industry ,Windows CE ,computer.software_genre ,Commit charge ,Internet Authentication Service ,Windows Server ,Converged storage ,Embedded system ,Data_FILES ,Microsoft Windows ,Operating system ,Group Policy ,business ,computer - Abstract
Publisher Summary Regardless of whether one chooses a Fiber Channel attached storage array or with Direct Attached Storage (DAS), he or her has to make the disks available to the Windows operating system. This chapter describes technologies to manage disk storage using Windows management applications and various components of the Windows Storage Stack. Two key components of the storage stack are the Virtual Disk Service (VDS) and VSS. VDS and VSS provide an abstraction layer that hides the hardware specifics of the underlying storage subsystems from storage management applications and applications like Exchange that want to take advantage of VSS. VDS provides a single interface to manage multivendor storage environments. It eliminates the necessity that a Windows administrator understands several different vendor-specific storage application interfaces, for example, HP StorageWorks Command View EVA or an application of the EMC ControlCenter family. Before Windows Server 2003 was released, the SCSIport driver was used as a device driver for storage devices. With Windows Server 2003, Microsoft released a new driver architecture called Storport. Storport allows one to have different configuration parameters per Host Bus Adapter (HBA). It an operating system has two paths to access storage device or disk; the single point of failure no longer exists, but the operating system now has to prevent that this single disk appears as two separate disks to the upper layers of the operating system. Solving this issue is the responsibility of a Multi Path I/O (MPIO) solution. In Windows Server 2003, Microsoft provided a MPIO framework that allows vendors to develop device-specific module (DSM) and implements the storage-specific functions. With Windows Server 2008, Storage Explorer can be used to gain an overview of storage infrastructure. Storage Explorer is an MMC snap-in that uses WMI to gather information about all components in the storage infrastructure.
- Published
- 2008
40. Introduction to Exchange 2007 Storage
- Author
-
Juergen Hasslauer and Pierre Bijaoui
- Subjects
Database ,business.industry ,Computer science ,Byte ,Unstructured data ,computer.software_genre ,User experience design ,Virtual address space ,Transaction log ,Converged storage ,business ,Message queue ,computer ,Database model - Abstract
Publisher Summary This chapter reviews the aspects of storage design for Microsoft Exchange 2007. Microsoft Exchange is a dominant mail and messaging platform, often used also as a corporate address book and time management application. Email is about sending and receiving data; for users, it's having a repository of relatively unstructured data and querying that repository similar to a database. Storage is therefore a critical component in Exchange 2007 deployment. Following the adoption of 64-bit computing by Exchange 2007, storage has become the most critical component in the design. The performance of the storage designed for Microsoft Exchange is critical to the overall user experience. Slow storage solutions for Exchange 2007 will lead to message queuing, sluggish response time, and delays in performing certain actions. When dealing with Exchange storage it is necessary to first work the requirements for the storage and then figure out the best solution to handle the requirements in a logical flow. Like Microsoft Exchange 2000, the Exchange 2007 extends the adoption of a multiple database model, where mailboxes could be held in several smaller databases, instead of just one big database in a single file. However with Exchange 2007 up to 50 databases can be defined for a single server, now that the barriers of the Virtual Address space (3 GB and a few bytes) of the Information Store process are broken, due to 64-bit computing. A single Exchange 2007 server can handle many more databases, allowing for a better granularity when dealing with individual databases and transaction log files.
- Published
- 2008
41. Astronomical image data compression by morphological skeleton transformation
- Author
-
L. Huang and Albert Bijaoui
- Subjects
Pixel ,business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Astronomy and Astrophysics ,Image processing ,Grayscale ,Photographic plate ,Transformation (function) ,Optics ,Space and Planetary Science ,Morphological skeleton ,Computer vision ,Artificial intelligence ,business ,Image compression ,Data compression - Abstract
Astronomical instruments currently provide a large amount of data. Nowadays, a large part of these data are image frames obtained with receivers of increasing size. The scan of large astronomical plates using fast microdensitometers gives image frames of over 30000×30000 pixels. More and more often, images are transmitted over a network in order to control the observations, to process the data, and to examine or to fill a data bank. The time taken for archiving, the cost of communication, the available memory given by magnetic tapes, and the limited bandwidth of transmission lines are reasons which lead us to examine the data compression of astronomical images. The astronomical image has the characteristic of being a set of astronomical sources in the sky background whose values are not zero. We are, in fact, only interested in the astronomical sources. Once a suitable detection is made, we generally want a compression without any distorsion. In this paper, we present a method which can be adapted for this purpose. It is based on morphological skeleton transformations. The experimental results show that it can give us an efficient compression. Moreover, the flexibility of choosing a structure element adapted to different images and the simplicity of implementation are other advantages of this method. Because of these characteristics, different compression applications may be treated.
- Published
- 1990
42. Exchange 2003 Architecture
- Author
-
Pierre Bijaoui
- Subjects
World Wide Web ,Workflow ,business.industry ,Computer science ,Scalability ,Distributed Component Object Model ,CAPICOM ,Meta Data Services ,The Internet ,Architecture ,Total cost of ownership ,business - Abstract
Publisher Summary This chapter reviews the Exchange 2003 architecture. The chapter identifies the main components and discusses the most critical components used in high-end environments as well as scale-up and scale-out models. Microsoft Exchange 2003 represents many features of both Microsoft Exchange 5.5 and Microsoft Commercial Internet Services (MCIS). The Microsoft Exchange product family has evolved by proposing a client/server-based model to a fully scalable high-end platform for enterprise and Internet messaging and collaboration. Microsoft Exchange is becoming an increasingly important source of information in an enterprise, and it can very well feed rich applications with information and processes, such as workflow processes. Some of the benefits of Microsoft Exchange 5.5 include improved scalability, lower total cost of ownership, and greater availability by enabling more mailboxes per server while enabling a high level of consolidation. Standards are upheld by supporting and enhancing the Internet-based protocols controlled by the Internet Engineering Task Force (IETF), which issues requests for comments (RFCs)—the basis for standards in the Internet world.
- Published
- 2007
43. Best Practices
- Author
-
Pierre Bijaoui
- Subjects
Engineering ,Bridging (networking) ,Windows Server ,business.industry ,Software deployment ,Best practice ,Server ,Real-time computing ,Disk array ,Audit ,Predictability ,business ,Computer network - Abstract
Publisher Summary This chapter discusses actual server configurations and provides a real-world context for the elements of theory. Microsoft continuously improves its product and technology offerings, thereby bridging a smaller gap between what the products can offer off the shelf and the solution that customers actually need. The chapter reviews the configuration guidelines for Windows Server 2003, which generally depend on the implementation guidelines and Windows server deployment policies. The Exchange Best Practice Analyzer (ExBPA) tool from Microsoft can effectively audit the Exchange environment. It can also make sure that the servers are configured according to evolving best practices and it can greatly diminish the uncertainties of a deployment. It is possible to scale up most servers in terms of processors and storage capacity. Back-end storage arrays or interconnects are generally employed for maximizing the predictability of the deployment to ensure that requirements for each of the components are properly formulated.
- Published
- 2007
44. Performance and Monitoring
- Author
-
Pierre Bijaoui
- Subjects
Engineering ,business.industry ,media_common.quotation_subject ,Real-time computing ,Environment controlled ,Workload ,Sizing ,Proactive maintenance ,Risk analysis (engineering) ,Software deployment ,business ,Function (engineering) ,Productivity ,Database transaction ,media_common - Abstract
Publisher Summary This chapter deals with mechanisms that ensure proactive maintenance of the environment, raise end-user satisfaction, and improve productivity by providing an adequately sized environment that can bear both the current and the anticipated transaction load. It is difficult to simulate or qualify an entire infrastructure in a controlled environment in that there are several areas of measurement and to determine the resource utilization as a function of the transaction workload. When aiming at an enterprise deployment, it is important to locate representative sites and attempt to model its workload for sizing the systems configuration. It is important to equip the messaging infrastructure with vertical and complete monitoring solutions. Vertical solutions aim at drilling down a particular application and providing an intelligent way to interpret the data and report events and activity. Complete monitoring solutions provide an overview of the computing infrastructure and associate many operating systems and application environments under a single viewpoint of reporting. It is often required in large-scale computing environments that require 24/7 monitoring.
- Published
- 2007
45. Variance stabilization
- Author
-
Albert Bijaoui, Jean-Luc Starck, and Fionn Murtagh
- Subjects
Noise ,Anscombe transform ,Computer science ,business.industry ,Image processing ,Computer vision ,Artificial intelligence ,Variance (accounting) ,business - Published
- 1998
46. Blind Source Separation of Multispectral Astronomical Images
- Author
-
Danielle Nuzillard and Albert Bijaoui
- Subjects
Physics ,business.industry ,Multispectral image ,Computer vision ,Artificial intelligence ,business ,Blind signal separation ,Remote sensing - Published
- 2006
47. Analysis of multiband astronomical images using multiscale tools
- Author
-
Christophe Benoist, Eric Slezak, Albert Bijaoui, and Anaïs Guennec
- Subjects
Image fusion ,Pixel ,business.industry ,Multispectral image ,Wavelet transform ,Computer vision ,Image processing ,Artificial intelligence ,Deconvolution ,Spectral bands ,business ,Object detection ,Mathematics - Abstract
Many regions of the sky are currently being observed with a high number of spectral bands with various instruments and this trend shall develop considerably in the coming years. Even with few wavelength-bands, it is not easy to match the objects identified in each individual image, or to get consistent measurements and classify them spectrally. A detection based on fusion images is proposed. Different algorithms are tested for building such an image. The best results in terms of object detection are obtained from those involving a deconvolution with a wavelet approach. Another way to sort the pixels of astronomical images into a coherent set of physical sources is to classify them following some basic assumptions. The main difficulty comes from the fact that astronomical sources fill a multidimensional continuum of spectral classes leading to a significant color classes increase with the number of bands. The pixels spectral behaviour is assumed here to be a superimposition of several pure elements. The resulting mixing categories define a set of intermediate classes, and the application of the matching pursuit algorithm allows then to get class percentages, providing very promising results for the analysis of multi-wavelength astronomical images.
- Published
- 2005
48. A Concept Of Evaluation Of Shape And Cell's Texture By Space Vectors Positions
- Author
-
L. Fongang, A. Houri, and A. Bijaoui
- Subjects
business.industry ,Image (category theory) ,Feature extraction ,Pattern recognition ,Mathematical morphology ,Texture (geology) ,Digital image ,Matrix (mathematics) ,Distribution (mathematics) ,Point (geometry) ,Computer vision ,Artificial intelligence ,business ,Mathematics - Abstract
Cells caracterization by mathematical morphology analy- sis of comsponding shape and biological texture images is describe. We suggest in this paper, a method based on cell's spatial reorientation by vectors stemming from his centre of gravity and rests on his contour. This method point out an simple way to get similar positions between two (or more) cells (or two domains of the same cell), during their comparizon. Analysis and comparizon parameters are derive from second-order statistics for stochastics textures analysis and, from chi-square distribution to capture struc- tures when co-occurrence matrix is used over structured (deter- niinistically or randomly) local subpattems. The method applicated to blood cells, gives an high iden- tification accuracy ; some examples are presented. MTRODUCTION. Textural and morphologycal cells caracterization of cor- responding digital images, by mathmatical analysis, requiered seve ral methods. For example : - cross-correlation - mathematical morphology Those algorithms are not sufficient to define an high rec- ognition accuracy, with comparizon to biologists visual analysis. In order to acheave morphologycal identification, the classification obtained using both methods must be improved. To fit mathemathi- cal identification to the biologists visual analysis, we added several evaluations tests. The laters consider textures, shapes and cells orientations scattering, relative to the intensity variations that oc- cured either in exposure time or during image digitalization, and then increase identification difficulties.
- Published
- 2005
49. A Texture Analysis By Mathematical Morphology. Application To Cells Discrimination
- Author
-
L. Fongang, A. Houri, and A. Bijaoui
- Subjects
Morphological gradient ,Texture compression ,Morphology (linguistics) ,Image texture ,business.industry ,Morphological skeleton ,Pattern recognition ,Image segmentation ,Artificial intelligence ,Mathematical morphology ,business ,Texture (geology) ,Mathematics - Published
- 2005
50. Wavelet applied to computer vision in astrophysics
- Author
-
Myriam Traina, E. Slezak, and Albert Bijaoui
- Subjects
Discrete wavelet transform ,business.industry ,Stationary wavelet transform ,Second-generation wavelet transform ,Wavelet transform ,Cascade algorithm ,Wavelet packet decomposition ,Wavelet ,Computer Science::Computer Vision and Pattern Recognition ,Computer vision ,Artificial intelligence ,Harmonic wavelet transform ,business ,Mathematics - Abstract
Multiscale analyses can be provided by application wavelet transforms. For image processing purposes, we applied algorithms which imply a quasi isotropic vision. For a uniform noisy image, a wavelet coefficient W has a probability density function (PDF) p(W) which depends on the noise statistic. The PDF was determined for many statistical noises: Gauss, Poission, Rayleigh, exponential. For CCD observations, the Anscombe transform was generalized to a mixed Gasus+Poisson noise. From the discrete wavelet transform a set of significant wavelet coefficients (SSWC)is obtained. Many applications have been derived like denoising and deconvolution. Our main application is the decomposition of the image into objects, i.e the vision. At each scale an image labelling is performed in the SSWC. An interscale graph linking the fields of significant pixels is then obtained. The objects are identified using this graph. The wavelet coefficients of the tree related to a given object allow one to reconstruct its image by a classical inverse method. This vision model has been applied to astronomical images, improving the analysis of complex structures.
- Published
- 2004
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