Gradient descent optimization of smoothed information retrieval metrics     

Olivier Chapelle  Mingrui Wu 《Information Retrieval》2010,13(3):216-235

Most ranking algorithms are based on the optimization of some loss functions, such as the pairwise loss. However, these loss functions are often different from the criteria that are adopted to measure the quality of the web page ranking results. To overcome this problem, we propose an algorithm which aims at directly optimizing popular measures such as the Normalized Discounted Cumulative Gain and the Average Precision. The basic idea is to minimize a smooth approximation of these measures with gradient descent. Crucial to this kind of approach is the choice of the smoothing factor. We provide various theoretical analysis on that choice and propose an annealing algorithm to iteratively minimize a less and less smoothed approximation of the measure of interest. Results on the Letor benchmark datasets show that the proposed algorithm achieves state-of-the-art performances.  相似文献   

A review of the penetration of Francophone research on intervention in physical education and sport in Anglophone journals since 2010     

Olivier Vors  Amélina Girard  Nathalie Gal-Petitfaux  Benoît Lenzen  Nicolas Mascret  Alain Mouchet 《Physical Education & Sport Pedagogy》2020,25(4):331-345

ABSTRACT

Introduction: Since the 1990s, the notion of intervention has expanded with growing interest in the analysis of practices in Francophone country. French-speaking research community considers intervention sciences as a specific field of research in sport and PE. The aim of this literature review was to characterize the penetration of Francophone research in the English-language literature in physical education and sport concerned with intervention since 2010 in the category ‘Education & Educational Research’ of the Journal Citation Reports (2017). This research was in line with the analysis of the papers presented during six Francophone congresses from 2000 to 2010 of the Association for Research on Intervention in Sport (Musard and Poggi 2015 Musard, Mathilde, and Marie-Paule Poggi. 2015. “Intervention in Physical Education and Sport: Trends and Developments in a Decade of Francophone Research.” Physical Education and Sport Pedagogy 20 (3): 250–267. doi:10.1080/17408989.2013.817008.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]).

Methods: The selection of articles was carried out in three stages: selection of journals, selection of articles manually, the second level of selection. The selection of journals is do in this category "Education & Educational Research" (JCR, 2017) focusing primarily on sport and physical education. Six journals met these criteria: Physical Education and Sport Pedagogy, European Physical Education Review, Journal of Teaching in Physical Education, Sport Education and society, Quest, Journal of Hospitality Leisure Sport & Tourism Education. Then, the selection of articles was manually analyzing all the publications of each journal since 2010 (almost 2000 articles) according to inclusion criteria "sport or physical education", "francophone authors", and "intervention". Each 46 articles selected was classified according to its theoretical framework. The last stage of selection corresponded to an analyze and an extension of the literature review by a French-speaking specialist in each theoretical framework.

Results: The results show that French-language research on/in/for intervention is in close connection with the international tradition. Some approaches such as didactique, a technological approach, and course of action, have a Francophone specificity based on various international theoretical anchors; others such as motor learning, social psychology, ecological approach come from non-French-speaking international theoretical frameworks.

Discussion and conclusion: These findings raise the question of the Francophone specificity of intervention sciences. Beyond particular French-speaking theoretical frameworks, concepts and concerns join Anglophone traditions. As in the international fields of ‘sport pedagogy’ or ‘praxis’, the Francophone intervention sciences are composed of a diversity of theoretical approaches and are focused towards an epistemology of action. These two communities can enrich each other and deserve more interaction and exchange.  相似文献   

Video production as a tool for raising educator awareness about collaborative teacher–parent partnerships     

Lesley Wood  Tilla Olivier 《Educational research; a review for teachers and all concerned with progress in education》2013,55(4):399-414

Background:?This article describes research undertaken with teachers working in a South African township school, where parental involvement is a persistent problematic issue.

Purpose:?The purpose of the study was to explore the use of video production as a tool for assisting teachers to explore their perceptions about parental involvement in education and how these perceptions impact on their relationships with parents.

Sample:?Nine teachers participated voluntarily in the study, seven from two different primary schools and two from the high school in the township. All the teachers were isiXhosa speaking and had grown up in communities similar to the one in which the school was situated.

Design and methods:?Following a participatory research approach, we guided the participating teachers to design and produce short videos about issues that they perceived to impact negatively on their teaching and learning. We then facilitated critical reflection on these videos, specifically exploring how they had portrayed the teacher–parent relationship in each case.

Results:?Through a content analysis of a structured focus group and their written responses to questions, we identified emergent themes that made it apparent that the participating teachers viewed parents in a negative light, indicating a lack of the respect that would be required for the formation and sustainment of co-operative relationships. These themes were then used to facilitate discussion to raise teacher awareness of how the teachers' perceptions of parents could hinder meaningful parental involvement.

Conclusion:?The article offers an example of how visual methodologies can be useful tools for beginning to raise teacher awareness around issues, as a precursor to helping teachers to take action to improve a given situation.  相似文献   

Increasing Participation in Study Abroad Programs: Organizational Strategies in Quebec CEGEPs     

Olivier Bégin-Caouette  Véronique Angers  Kimon Niflis 《Community College Journal of Research & Practice》2013,37(6):568-583

International experience is said to promote students’ intercultural sensitivity, employability and academic achievement; yet few community college students go abroad during their studies. This study aims to identify which organizational strategies are related to the participation rate in study abroad programs (SAPs). Taking the case of Quebec general and vocational colleges (CEGEPs [collèges d’enseignement general et professionnel]), a group-frequency analysis was performed on data obtained through a survey to which 39 CEGEPs responded (81% of the population). Using Knight’s (1999, 2004) terminology of organizational strategies, findings reveal that institutions with higher participation rates use four strategies to a greater extent: institutional commitment towards internationalization; educative mission statement referring to SAPs; international offices; and funding offered to students who participate in SAPs. A standard regression confirms that commitment and funding are positively correlated with student participation rates.  相似文献   

Effect of physiological harvest stages on the composition of bioactive compounds in Cavendish bananas   总被引：1，自引：0，他引：1  

Christelle Bruno Bonnet  Olivier Hubert  Didier Mbeguie-A-Mbeguie  Dominique Pallet  Abel Hiol  Max Reynes  Patrick Poucheret 《Journal of Zhejiang University. Science. B》2013,14(4):270-278

The combined influence of maturation, ripening, and climate on the profile of bioactive compounds was studied in banana (Musa acuminata, AAA, Cavendish, cv. Grande Naine). Their bioactive compounds were determined by the Folin-Ciocalteu assay and high-performance thin layer chromatographic (HPTLC) method. The polyphenol content of bananas harvested after 400 degree days remained unchanged during ripening, while bananas harvested after 600 and 900 degree days exhibited a significant polyphenol increase. Although dopamine was the polyphenol with the highest concentration in banana peels during the green developmental stage and ripening, its kinetics differed from the total polyphenol profile. Our results showed that this matrix of choice (maturation, ripening, and climate) may allow selection of the banana (M. acuminata, AAA, Cavendish, cv. Grande Naine) status that will produce optimal concentrations of identified compounds with human health relevance.  相似文献   

Intensity,recovery kinetics and well-being indices are not altered during an official FIFA futsal tournament in Oceanian players     

Keyne Charlot  Paul Zongo  Anthony Scott Leicht  Olivier Hue  Olivier Galy 《Journal of sports sciences》2016,34(4):379-388

Physiological responses (intensity and recovery kinetics) and well-being indices were examined during a 4-day FIFA international tournament. Ten outfield New Caledonian players (age: 25.5 ± 3.8 years; height: 170 ± 7 cm; weight: 70.7 ± 8.6 kg) were assessed during the four matches. Players’ aerobic and anaerobic capacities were measured before the tournament while heart rate (HR), intra-matches recovery and well-being indices (Hooper index) were measured throughout the tournament. HR (168 ± 8 bpm), exercise intensity (83.4 ± 2.3% of HR reserve) and recovery indices were similar throughout the tournament. Well-being indices were largely alike during the tournament while rating of perceived exertion increased throughout the tournament that was not associated with HR or well-being indices. High aerobic and anaerobic capacities were associated with high match intensities and slow recovery indices. In summary, match intensity assessed by HR, recovery kinetics and well-being of Oceanian futsal players were not modified during a 4-day FIFA futsal tournament. Assessment of aerobic and anaerobic capacities may be useful to select players for optimal performance during this type of international tournament.  相似文献   

Running mechanical alterations during repeated treadmill sprints in hot versus hypoxic environments. A pilot study     

Olivier Girard  Franck Brocherie  Jean-Benoit Morin  Grégoire P. Millet 《Journal of sports sciences》2016,34(12):1190-1198

We determined if performance and mechanical running alterations during repeated treadmill sprinting differ between severely hot and hypoxic environments. Six male recreational sportsmen (team- and racket-sport background) performed five 5-s sprints with 25-s recovery on an instrumented treadmill, allowing the continuous (step-by-step) measurement of running kinetics/kinematics and spring-mass characteristics. These were randomly conducted in control (CON; 25°C/45% RH, inspired fraction of oxygen = 20.9%), hot (HOT; 38°C/21% RH, inspired fraction of oxygen = 20.9%; end-exercise core temperature: ~38.6°C) and normobaric hypoxic (HYP, 25°C/45% RH, inspired fraction of oxygen = 13.3%/simulated altitude of ~3600 m; end-exercise pulse oxygen saturation: ~84%) environments. Running distance was lower (P < 0.05) in HOT compared to CON and HYP for the first sprint but larger (P < 0.05) sprint decrement score occurred in HYP versus HOT and CON. Compared to CON, the cumulated distance covered over the five sprints was lower (P < 0.01) in HYP but not in HOT. Irrespective of the environmental condition, significant changes occurred from the first to the fifth sprint repetitions (all three conditions compounded) in selected running kinetics (mean horizontal forces, P < 0.01) or kinematics (contact and swing times, both P < 0.001; step frequency, P < 0.001) and spring-mass characteristics (vertical stiffness, P < 0.001; leg stiffness, P < 0.01). No significant interaction between sprint number and condition was found for any mechanical data. Preliminary evidence indicates that repeated-sprint ability is more impaired in hypoxia than in a hot environment, when compared to a control condition. However, as sprints are repeated, mechanical alterations appear not to be exacerbated in severe (heat, hypoxia) environmental conditions.  相似文献   

‘Zip’: An adhesive plastic film in architectural drawings     

Marion Cinqualbre  Maroussia Duranton  Jéromine Baudin  Stéphane Bouvet  Olivier Cinqualbre  Emilie Le Bourg 《文物保护研究》2016,61(3):283-285

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Doctoral students’ experiences leading to completion or attrition: a matter of sense,progress and distress     

Christelle Devos  Gentiane Boudrenghien  Nicolas Van der Linden  Assaad Azzi  Mariane Frenay  Benoit Galand  Olivier Klein 《European Journal of Psychology of Education - EJPE》2017,32(1):61-77

A central trend in qualitative studies investigating doctoral students’ dropout is to stress the importance of students’ integration and socialisation in their working environment. Yet, few of these studies actually compared the experiences of doctoral students who completed or quit their PhD. In order to overcome this limitation and identify the factors that differentiate these two groups, the present study interviewed 21 former doctoral students: 8 completers and 13 non-completers. The results show that what best differentiates these two groups of participants is the extent to which they feel that they are moving forward, without experiencing too much distress, on a research project that makes sense to them. We assume that this set of factors is central in the dropout process. Support from doctoral peers was found to play a positive role overall but did not contribute to differentiating the two groups, presumably because peers have a limited impact on dissertation progress. Supervisors’ support was central to the participants’ stories; it is thus assumed to play a role in the process, but this role is complex and needs further investigation. These results call for a stronger consideration of the doctoral task itself when investigating the process of persistence and attrition and for a more integrated framework that considers jointly both task- and environment-related aspects.  相似文献   

The effect of redundant text in multimedia instruction     

Eric Jamet  Olivier Le Bohec 《Contemporary educational psychology》2007,32(4):588-598

The purpose of this study was to examine the redundancy effects obtained when spoken information was duplicated in writing during the learning of a multimedia document. Documents consisting of diagrams and spoken information on the development of memory models were presented to three groups of students. In the first group, no written text was presented. In the second, written sentences redundant with the spoken information were progressively presented on the screen while in the third group, these written sentences were presented together. The results show that whatever the type of text presentation (sequential or static), the duplication of information in the written mode led to a substantial impairment in subsequent retention and transfer tests as well as in a task in which the memorization of diagrams was evaluated. This last result supports the hypothesis that the visual channel is overloaded as the cognitive theory of multimedia learning suggests.  相似文献