Design area for assistance to maintenance based on augmented reality.

International audienceOne of the main weaknesses with traditional computing is the fact that the numerical world of the computer is decoupled from the user's real world. The application of Augmented Reality (AR) can provide interactive systems in which real objects and computer data are combined in a cohesive way. This new paradigm has many potential applications in various fields, in particular in the maintenance domain. It allows the user to see computer generated virtual objects superimposed to the real world through the see-through Head Mounted Display (HMD). The technician of maintenance, when using this system, can interact with the virtual world and have additional information, such as instruction for performing maintenance tasks in form of text messages, images, 3-D models of pieces or audio such as speech instruction. In this paper, we propose a design process of the maintenance system focused on the analysis of the interaction between the user, the system and the real world. This area is based on the UML notation. The use of UML represents our ergonomic and software design process basis for AR systems. This process also is based on ergonomic characteristics study within a UML system description and on the hybrid PAC-Amodeus model architecture adaptation for the AR systems

Réalité augmentée à partir d'une séquence vidéo en utilisant la stéréoscopie dense.

International audienceCet article s'intéresse à la réalité augmentée, c'est à dire à l'intégration d'objets virtuels générés par ordinateur dans une séquence d'images en gérant les occultations. L'occultation est l'un des problèmes cruciaux en réalité augmentée. Il consiste à tenir compte des interactions entre les éléments virtuels insérés et la scène réelle: les parties occultées de ces éléments doivent être déterminées. La méthode proposée repose sur le calcul des cartes de disparité en utilisant les techniques de mise en correspondance denses. Afin de retrouver des cartes de disparité denses, nous présentons dans cet article deux techniques d'appariement. La première est basée sur la programmation dynamique. Bien que cette méthode donne des résultats satisfaisants, elle reste néanmoins très gourmande en temps de calcul. Afin améliorer le temps de calcul ainsi que la qualité des résultats, nous proposons une autre méthode dite hybride basée sur l'approche multi résolution et la programmation dynamique. Les cartes de disparité ainsi obtenues sont appliqués en réalité augmentée afin d'intégrer de manière réaliste des objets virtuels générées par ordinateur dans une séquence d'images. La méthode d'augmentation proposée réduit considérablement l'intervention de l'utilisateur. L'applicabilité de la méthode est démontrée sur de nombreuses séquences d'images

Espace de Conception d'un système d'aide à la maintenance basé sur la réalité augmentée.

International audienceL'un des principaux reproches que l'on fait à l'informatique traditionnelle est que le monde numérique de l'ordinateur est trop déconnecté du monde réel dans lequel les utilisateurs évoluent. Parvenir à rompre la frontière entre l'ordinateur et le monde réel dans le but d'accroître les capacités de l'utilisateur à percevoir les informations, à exécuter des tâches, ou encore à communiquer, le tout sans coupure avec son environnement habituel est l'un des enjeux de tout système utilisant le concept de la réalité augmentée (RA). Ce nouveau paradigme a p r i s une place importante dans divers domaines notamment dans le domaine de la maintenance. En effet, il permet tout en optimisant les coûts de maintenance, de fournir aux techniciens travaillant sur des équipements complexes des informations supplémentaires dont ils ont besoin sur leur lieu de travail. Dans cet article, nous proposons notre démarche de conception d'un système d'aide à la maintenance, centré sur l'analyse de l'interaction entre l'utilisateur, le système et le monde réel. Cet espace repose sur la notation UML. C'est un langage de modélisation visuel d'usage général utilisé pour spécifier, visualiser, construire et documenter les constituants d'un système logiciel. Son objectif est de faciliter la compréhension, l'analyse, la conception et la maintenance des systèmes. L'utilisation d'UML constitue la base de notre démarche de conception ergonomique et logicielle de systèmes de RA. Cette démarche se fonde en outre sur l'étude de propriétés ergonomiques au sein de la description UML d'un système et sur l'adaptation du modèle d'architecture PAC-Amodeus aux systèmes de RA

Measuring the quality of hotel services using the Servqual model Field study on some four-star hotels

تهدف هذه الدراسة إلى قياس جودة خدمات الفنادق الجزائرية من صنف أربع نجوم باستخدام نموذج Servqual، وهذا من وجهة نظر الزبائن، ولتحقيق هدف الدراسة واختبار فرضيتها تم تصميم استبيان وتوزيعه على عينة مكونة من 200 من زبائن أربع فنادق مختارة بمنطقة الشرق الجزائري، تم استرجاع منها 102 استبيان. إعتمد الباحثان أسلوب التحليل الإحصائي الوصفي والاستدلالي، لوصف وتحليل بيانات الدراسة، واختبار فرضيتها. توصلت الدراسة إلى نتيجة أساسية مفادها أن مستوى جودة الخدمة المدركة أكبر من المستوى المتوقع أي أن جودة الخدمة مرضية، كما أشارت الدراسة إلى وجود بعض النقائص المتعلقة بنوعية موظفي الفنادق محل الدراسة وكذا قصور في تأدية بعض الخدمات الأساسية مثل الخدمات الإلكترونية.This study aims tomeasure the quality ofservicesofthe AlgerianHotelsFour Starclassusing Servqual model,andthisfrom the viewpoint ofcustomers,To achieve theobjective of the studyand test thepremisequestionnairewasdesignedand distributed toa sample of200customersof thefour selectedhotelsthe eastAlgerianregion, of which 102wereretrievingquestionnaire. The study concludedthe conclusion thatthe perceivedservice quality is better-than-expected level service quality in the hotels under study,This means thatservicequality is satisfactory ; the study, alsoindicatedsome shortcomingsrelated tothe quality ofthe hotel staffunder studyand as well asdeficiencies inthe performance ofsomeessential services such ase-services

Pressurized Liquid Extraction for the Recovery of Carotenoids and Functional Compounds from Green and Orange Dunaliella salina Biomasses

In recent years, intensive research has been conducted on natural carotenoids extraction using several processes. Conventional extraction methods require high amounts of solvents and a long extraction time. However, pressurized liquid extraction demonstrated to be an interesting method. The extraction efficiencies of pressurized liquid for the recovery of carotenoids, from the green and the orange biomasses of the microalga Dunaliella salina DunaDZ1, are described. Organic solvents were tested including ethanol, n-hexane, ethyl acetate and a mixture of n-hexane:ethanol (3:4). Moreover, three extraction temperatures were used (90, 120 and 150 °C) at constant pressure. Extraction efficiency and extracts characterization were conducted. Results have shown that temperature has a positive effect on extraction yield. HPLC characterization showed that β-carotene is the main carotenoid in the orange biomass, and lutein in the green biomass, with the presence of other minor carotenoids in both biomasses. The highest carotenoid amounts were found in the n-hexane orange biomass extract, with β-carotene isomers as the main carotenoid (138.54 and 357.10 mg/g of dry extract, for cis and trans isomers, respectively). Otherwise, extracts obtained at the lowest tested temperature provided the best carotenoid yields. The best results for the antioxidant activity were obtained at 120 °C for orange biomass ethyl acetate extract

Nutrition transition among adolescents of a south-Mediterranean country: dietary patterns, association with socio-economic factors, overweight and blood pressure. A cross-sectional study in Tunisia

Background: The increase in the burden of chronic diseases linked to the nutrition transition and associated dietary and lifestyle changes is of growing concern in south and east Mediterranean countries and adolescents are at the forefront of these changes. This study assessed dietary intake and association with socio-economic factors and health outcomes among adolescents in Tunisia. Methods: Cross-sectional survey (year 2005); 1019 subjects 15-19 y. from a clustered random sample. Dietary intake was assessed by a validated semi-quantitative frequency questionnaire (134 items) as was physical activity; the Diet Quality Index International measured diet quality; dietary patterns were derived by multiple correspondence analysis from intakes of 43 food groups. Body Mass Index (BMI) >= 85(th) and 95(th) percentile defined overweight and obesity. Waist Circumference (WC) assessed abdominal fat. High blood pressure was systolic (SBP) or diastolic blood pressure (DBP) >= 90(th) of the international reference for 15-17 y., and SBP/DBP >= 120/80 mm Hg for 18-19 y. Results: Energy intake levels were quite high, especially for females. The macro-nutrient structure was close to recommendations but only 38% had a satisfactory diet quality. A main traditional to modern dietary gradient, linked to urbanisation and increased economic level, featured an increasing consumption of white bread, dairy products, sugars, added fats and fruits and decreasing consumption of oils, grains, legumes and vegetables; regarding nutrients this modern diet score featured a decreasing relationship with total fat and an increase of calcium intake, but with an increase of energy, sugars and saturated fat, while vitamin C, potassium and fibre decreased. Adjusted for age, energy and physical activity, this modern pattern was associated with increased overweight in males (2(nd) vs. 1(st) tertile: Prevalence Odds-Ratio (POR) = 4.0[1.7-9.3], 3(rd) vs. 1st: POR = 3.3[1.3-8.7]) and a higher WC. Adjusting also for BMI and WC, among females, it was associated with decreased prevalence of high blood pressure (2(nd) vs. 1(st) tertile: POR = 0.5[0.3-0.8], 3(rd) vs. 1(st) tertile: POR = 0.4[0.2-0.8]). Conclusion: The dietary intake contrasts among Tunisian adolescents, linked to socio-economic differentials are characteristic of a nutrition transition situation. The observed gradient of modernisation of dietary intake features associations with several nutrients involving a higher risk of chronic diseases but might have not only negative characteristics regarding health outcomes

Blood pressure and associated factors in a North African adolescent population. a national cross-sectional study in Tunisia

<p>Abstract</p> <p>Background</p> <p>In southern and eastern Mediterranean countries, changes in lifestyle and the increasing prevalence of excess weight in childhood are risk factors for high blood pressure (BP) during adolescence and adulthood. The aim of this study was to evaluate the BP status of Tunisian adolescents and to identify associated factors.</p> <p>Methods</p> <p>A cross-sectional study in 2005, based on a national, stratified, random cluster sample of 1294 boys and 1576 girls aged 15-19 surveyed in home visits. The socio-economic and behavioral characteristics of the adolescents were recorded. Overweight/obesity were assessed by Body Mass Index (BMI) from measured height and weight (WHO, 2007), abdominal obesity by waist circumference (WC). BP was measured twice during the same visit. Elevated BP was systolic (SBP) or diastolic blood pressure (DBP) ≥ 90th of the international reference or ≥ 120/80 mm Hg for 15-17 y., and SBP/DBP ≥ 120/80 mm Hg for 18-19 y.; hypertension was SBP/DBP ≥ 95th for 15-17 y. and ≥ 140/90 mm Hg for 18-19 y. Adjusted associations were assessed by logistic regression.</p> <p>Results</p> <p>The prevalence of elevated BP was 35.1%[32.9-37.4]: higher among boys (46.1% vs. 33.3%; <it>P </it>< 0.0001); 4.7%[3.8-5.9] of adolescents had hypertension. Associations adjusted for all covariates showed independent relationships with BMI and WC: - obesity vs. no excess weight increased elevated BP (boys OR = 2.1[1.0-4.2], girls OR = 2.3[1.3-3.9]) and hypertension (boys OR = 3.5[1.4-8.9], girls OR = 5.4[2.2-13.4]), - abdominal obesity (WC) was also associated with elevated BP in both genders (for boys: 2nd vs. 1st tertile OR = 1.7[1.3-2.3], 3rd vs.1st tertile OR = 2.8[1.9-4.2]; for girls: 2nd vs. 1st tertile OR = 1.6[1.2-2.1], 3rd vs.1st tertile OR = 2.1[1.5-3.0]) but only among boys for hypertension. Associations with other covariates were weaker: for boys, hypertension increased somewhat with sedentary lifestyle, while elevated BP was slightly more prevalent among urban girls and those not attending school.</p> <p>Conclusion</p> <p>Within the limits of BP measurement on one visit only, these results suggest that Tunisian adolescents of both genders are likely not spared from early elevated BP. Though further assessment is likely needed, the strong association with overweight/obesity observed suggests that interventions aimed at changing lifestyles to reduce this main risk factor may also be appropriate for the prevention of elevated BP.</p