Localisation pédestre : Synthèse bibliographique et illustration d'une approche par vision monoculaire embarquée

National audienceLocate our position is one of the tasks we naturally do with our view and our memory. However, ensuring this task in an artificial way is still a challenge for the whole community of computer vision. This paper presents a detailed literature review of pedestrian localization systems and their technologies. In the context of the visually impaired pedestrian navigation assistance, we also present an innovative solution based on the vision localization for both outdoor and indoor navigation. This new solution is established based on the independence of any collective equipment.Se localiser est une des tâches que nous faisons naturellement grâce à notre vue et notre mémoire. Cependant, l'assurer artificiellement demeure un défi pour toute la communauté de la vision par ordinateur. Cette communication présente une revue de la littérature détaillée des systèmes de localisation pédestre et de ses technologies. Dans le contexte de l'assistance à la navigation pédestre des déficients visuels, nous proposons aussi une solution innovante, pour un fonctionnement efficace aussi bien en extérieur qu'en intérieur, fondée sur l'indépendance vis-à-vis de l'équipement collectif

Fonctionnement familial et compétence sociale des élèves en difficulté de comportement à l’école secondaire

Cet article porte sur l'évaluation d'un programme d'intervention destiné à des adolescents qui ont des difficultés de comportement à l'école et à la maison. L'intervention a compris trois entrevues avec tous les membres d'une famille, une série de rencontres de groupe avec les parents et, pour les adolescents, un programme d'entraînement aux habiletés sociales. Les résultats à l'autoévaluation indiquent une meilleure perception des habiletés d'autocontrôle et des habiletés sociales globales pour les élèves qui ont bénéficié des volets « adolescents » et « parents », ce que ne corrobore pas l'évaluation faite par les enseignants et les parents. L'évaluation de l'organisation familiale montre une amélioration pour les familles qui ont pris part aux deux volets du programme et une diminution du nombre de conflits dans celles dont les adolescents ont participé seulement à l'entraînement aux habiletés sociales.This article describes the evaluation of a program for adolescents with behavior difficulties at school and at home. The program was composed of three interviews with all the family members, a series of group meetings with parents, and a social skill training program for students. The results of self-evaluation show that students who participated in the "adolescent" and "parent" programs had a more favourable perception of both selfcontrol skills and global social skills. However, this was not found in teachers' and parents' evaluation. An evaluation of the family organization shows improvements for those families who participated in both parts of the program and a decrease in the number of conflicts in those families in which the adolescents participated only in the social skills training program.Este articulo trata sobre la evaluaciôn de un programa de intervencion destinado a adolescentes que tienen problemas de comportamiento en la escuela y en el hogar. La intervencion comprendio très entrevistas con todos los miembros de una familia, una série de reuniones de grupo con los padres y, para los adolecentes, un programa de entrenamiento a las habilidades sociales. Los resultados de la autoevaluacion indican una mejor percepciôn de las habilidades de autocontrol y de las habilidades sociales globales en los alumnos que realizaron las actividades "adolescentes" y "padres", Io que no corrobora la evaluaciôn hecha por los docentes y por los padres. La evaluaciôn de la organization familiar muestra una mejora en las familias que han tornado parte a las dos actividades del programa y una disminucion de la cantidad de conflictos en aquellas en las que los adolecentes participaron solamente al entrenamiento a las habilidades sociales.In diesem Artikel geht es um die kritische Bewertung eines Interventionsprogramms fur Jugendliche, die im schulischen und familiaren Bereich Verhaltensschwierigkeiten haben. Die Intervention sah drei Interviews mit alien Mitgliedern einer Familie, eine Série von Gruppenbegegnungen mit den Eltern sowie ein Programm zum Einûben sozialer Fàhigkeiten fiir die Schiller vor. Eine Selbstbewertung ergab, dass diejenigen Schiller, die die Programmkompo-nenten "Jugendliche" und "Eltern" absolviert hatten, ein besseres Verstândnis der Fàhigkeiten zur Selbstkontrolle sowie der allgemeinen sozialen Fàhigkeiten besafien, was nicht mit der Bewertung von Seiten der Eltern und der Lehrer ùbereinstimmte. Die Bewertung der familiaren Seite zeigt eine Verbesserung bei den Familien, die an beiden Programmkomponenten teilgenommen hatten sowie eine Abnahme der Konfliktsituationen bei denjenigen Familien, wo die Jugendlichen nur am Einûben sozialer Fàhigkeiten teilgenommen hatten

Gender differences in the long-term effects of a nutritional intervention program promoting the Mediterranean diet : changes in dietary intakes, eating behaviors, anthropometric and metabolic variables

Long-term adherence to principles of the Mediterranean diet (MedDiet) following a nutritional intervention promoting the Mediterranean food pattern in Canadian men and women is not known. Moreover, gender differences in dietary and metabolic profile in such an intervention context has never been addressed. Objective was to determine gender differences in long-term effects of a 12-week nutritional intervention program promoting the adoption of the MedDiet and based on the Self-Determination Theory (SDT) on dietary intakes, eating behaviors, anthropometric and metabolic variables, in men and women presenting cardiovascular risk factors. Methods Sixty-four men and 59 premenopausal women were recruited. The 12-week nutritional program used a motivational interviewing approach and included individual and group sessions. A food frequency questionnaire was administered to evaluate dietary intakes from which a Mediterranean score (Medscore) was derived and the Three-Factor Eating Questionnaire allowed assessment of eating behaviors. Measurements were performed at baseline and after the 12-week nutritional intervention, and then at 3 and 6-month post intervention. Results No gender difference was observed in changes in the Medscore during the nutritional intervention and follow-up. However, the Medscore returned towards baseline values during follow-up in men and women (P <0.0001). Men reported larger decreases in red and processed meat and larger increases in whole fruit intakes than women (P = 0.03 and P = 0.04, respectively). Men showed a greater decrease in habitual susceptibility to disinhibition than women (P = 0.03). A gender by time interaction was found for waist circumference, i.e. men had lower waist circumference at the end of the intervention as well as at follow-up than at baseline while women’s waist circumference decreased in response to the intervention only (P = 0.05). As for metabolic variables, changes observed in total-cholesterol (C) to HDL-C ratio, triglyceride levels and triglycerides to HDL-C ratio were more pronounced in men than in women after the intervention as well as at follow-up (P =0.03). Conclusions Our results indicate that the 12-week nutritional intervention based on the SDT leads to more pronounced beneficial changes in long-term dietary intakes in men than in women and to greater improvements in metabolic profile in men

Effects of a nutritional intervention program based on the self-determination theory and promoting the Mediterranean diet

Our objective was to determine gender differences in the impact of a nutritional intervention based on the selfdetermination theory and promoting the Mediterranean diet on changes in eating-related self-determined motivation and adherence to the Mediterranean diet. Changes in eating-related self-determined motivation were larger in men than in women in response to the intervention and at follow-up, but the magnitude of change decreased with time in both genders. Changes in eating-related self-determined motivation were positively associated with changes in the Mediterranean diet adherence in response to the intervention and at follow-up in men only, suggesting that the nutritional program seems to fit better men than women

Differences between men and women in dietary intakes and metabolic profile in response to a 12-week nutritional intervention promoting the Mediterranean diet

Few studies have compared men and women in response to nutritional interventions but none has assessed differences between men and women in the response to a nutritional intervention programme based on the self-determination theory (SDT) and using the Mediterranean diet (MedDiet) as a model of healthy eating, in a context of CVD prevention and within a non-Mediterranean population. The present study aimed to document differences between men and women in changes in dietary, anthropometric and metabolic variables, in response to a nutritional intervention programme promoting the adoption of the MedDiet and based on the SDT. A total of sixty-four men and fifty-nine premenopausal women presenting risk factors for CVD were recruited through different media advertisements in the Québec City Metropolitan area (Canada). The 12-week nutritional programme used a motivational interviewing approach and included individual and group sessions. A validated FFQ was administered to evaluate dietary intakes from which a Mediterranean score (Medscore) was derived. Both men and women significantly increased their Medscore in response to the intervention (P < 0·0001). Men showed a significantly greater decrease in red and processed meat (-0·4 (95 % CI -0·7, -0·1) portions per d) and a greater increase in fruit (0·9 (95 % CI 0·2, 1·6) portions per d) intakes than women. Significant decreases were observed for BMI and waist circumference in both men and women (P = 0·04). Significant greater decreases were found for total cholesterol (total-C):HDL-cholesterol (HDL-C) (-0·2; 95 % CI -0·4, -0·03) and TAG:HDL-C (-0·2; 95 % CI -0·4, -0·04) ratios in men than in women. When adjusting for the baseline value of the response variable, differences between men and women became non-significant for red and processed meat and fruit intakes whereas significant differences between men and women (i.e. larger increases in men than women) were observed for legumes, nuts and seeds (0·6 (95 % CI 0·2, 1·0) portions per d) and whole-grain products (0·5 (95 % CI 0·01, 1·0) portions per d) intakes. For metabolic variables, differences between men and women became non-significant for total-C:HDL-C and TAG:HDL-C ratios when adjusted for the baseline value of the response variable. The present results suggest that the nutritional intervention promoting the adoption of the Mediterranean diet and based on the SDT led to greater improvements in dietary intakes in men than in women, which appear to have contributed to beneficial anthropometric and metabolic changes, more particularly in men. However, the more deteriorated metabolic profile found in men at baseline seems to contribute to a large extent to the more beneficial changes in CVD risk factors observed in men as compared with wome

COMPETITIVE OR WEAK COOPERATIVE STOCHASTIC LOTKA-VOLTERRA SYSTEMS CONDITIONED TO NON-EXTINCTION

International audienceWe are interested in the long time behavior of a two-type density-dependent biological population conditioned to non-extinction, in both cases of competition or weak cooperation between the two species. This population is described by a stochastic Lotka-Volterra system, obtained as limit of renormalized interacting birth and death processes. The weak cooperation assumption allows the system not to blow up. We study the existence and uniqueness of a quasi-stationary distribution, that is convergence to equilibrium conditioned to non extinction. To this aim we generalize in two-dimensions spectral tools developed for one-dimensional generalized Feller diffusion processes. The existence proof of a quasi-stationary distribution is reduced to the one for a $d$-dimensional Kolmogorov diffusion process under a symmetry assumption. The symmetry we need is satisfied under a local balance condition relying the ecological rates. A novelty is the outlined relation between the uniqueness of the quasi-stationary distribution and the ultracontractivity of the killed semi-group. By a comparison between the killing rates for the populations of each type and the one of the global population, we show that the quasi-stationary distribution can be either supported by individuals of one (the strongest one) type or supported by individuals of the two types. We thus highlight two different long time behaviors depending on the parameters of the model: either the model exhibits an intermediary time scale for which only one type (the dominant trait) is surviving, or there is a positive probability to have coexistence of the two species

Identification of a novel truncating PALB2 mutation and analysis of its contribution to early-onset breast cancer in French-Canadian women

Abstract Background PALB2 has recently been identified as a breast cancer susceptibility gene. PALB2 mutations are rare causes of hereditary breast cancer but may be important in countries such as Finland where a founder mutation is present. We sought to estimate the contribution of PALB2 mutations to the burden of breast cancer in French Canadians from Quebec. Methods We screened all coding exons of PALB2 in a sample of 50 French-Canadian women diagnosed with either early-onset breast cancer or familial breast cancer at a single Montreal hospital. The genetic variants identified in this sample were then studied in 356 additional women with breast cancer diagnosed before age 50 and in 6,448 newborn controls. Results We identified a single protein-truncating mutation in PALB2 (c.2323 C>T, resulting in Q775X) in 1 of the 50 high-risk women. This variant was present in 2 of 356 breast cancer cases and in none of 6,440 newborn French-Canadian controls (P = 0.003). We also identified two novel new non-synonymous single nucleotide polymorphisms in exon 4 of PALB2 (c.5038 A>G [I76V] and c.5156 G>T [G115V]). G115V was found in 1 of 356 cases and in 15 of 6,442 controls (P = 0.6). The I76V variant was not identified in either the extended case series or the controls. Conclusion We have identified a novel truncating mutation in PALB2. The mutation was found in approximately 0.5% of unselected French-Canadian women with early-onset breast cancer and appears to have a single origin. Although mutations are infrequent, PALB2 can be added to the list of breast cancer susceptibility genes for which founder mutations have been identified in the French-Canadian population

Outdoor/Indoor Vision Based Localization for Blind Pedestrian Navigation Assistance

International audienceThe most challenging issue of the navigation assistive systems for the visually impaired is the instantaneous and accurate spatial localization of the user. Most of the previous proposed systems are based on GPS sensors. But, low cost versions have clearly insufficient accuracy for pedestrian use. Furthermore, they are confined to outdoor navigation with severe failing in urban area. This paper presents a new approach for localizing a person by using a single body mounted camera and computer vision techniques. Instantaneous accurate localization and heading estimates of the person are computed from images as the trip progresses along a memorised path. A first portable prototype has been tested for outdoor as well as indoor pedestrian trips. Experimental results demonstrate the effectiveness of the vision based localization: the accuracy around twenty centimetres, allows guiding and keeping the blind in a navigation corridor along the intended path. In combination with a suitable guiding interface, such a localization system will propose a convenient assistive navigation for the visually impaired