A driver model of a two-man bobsleigh     

Francesco Braghin  Mauro Donzelli  Stefano Melzi  Edoardo Sabbioni 《Sports Engineering》2011,13(4):181-193

Up to now, the optimization of structural parameters affecting the performance of a bobsleigh has been carried out mainly on the basis of athletes’ feedback, thus leading to a series of small modifications without univocal guidelines. Even though on-track tests represent a basic step for the final tuning of the sled, experimentation does not seem to represent an appropriate tool to objectively determine the influence of such structural parameters on the overall performance. In fact, their effect can easily be masked by driving errors, changes in the ice surface conditions and temperature thus requiring repeated tests for achieving statistical evidence. For this reason, numerical analysis, carried out with a 3D model of the bobsled, turns out to be a privileged instrument to optimize bob design although limitations in the sled model (e.g. ice friction properties that still have to be fully understood) may affect the obtained results. However, such tool is able to provide useful indications only if a correct driver model is implemented. This work focuses on the development of a numerical model of a bobsleigh driver that aims at reproducing the driving behaviour of real-world cup drivers and is basically made up of two steps: the identification of the trajectory that allows minimizing run time and the determination of the driver’s inputs to exactly follow that trajectory. For comparison purposes, the simulated driver’s inputs are compared with recorded ones on Cesana Pariol Olympic track.  相似文献   

Anxiety and self-esteem as mediators of the relation between family communication and indecisiveness in adolescence     

Valentina Lo Cascio  Giovanni Guzzo  Francesco Pace  Ugo Pace 《International Journal for Educational and Vocational Guidance》2013,13(2):135-149

In this study, we explored the unique and common contributions of anxiety, self-esteem, and family communication on indecisiveness among adolescents. Three hundred and fifty pupils from 13 to 16 years of age completed self-report measures on indecisiveness, quality of family communication, trait anxiety, and self-esteem. The findings in this study showed that students’ indecisiveness is predicted by family communication mediated by anxiety and self-esteem. These results have important implications for practice as it stresses the importance of anxiety and self-esteem. Nevertheless, the counselors could also focus on enhancing relationship-building skills by introducing the adolescents’ career formation as an adolescent–parent joint project.  相似文献   

“Is there an equal (amount of) juice?” Exploring the repeated question effect in conservation through conversation     

Aleksandar Baucal  Francesco Arcidiacono  Nevena Budjevac 《European Journal of Psychology of Education - EJPE》2013,28(2):475-495

The aim of this paper is to highlight and discuss advantages and constraints of different methods applied within the field of children's thinking studies, through the test of the repeated question hypothesis validity, using the conservation of liquid task. In our perspective, the Piagetian interview is an ecologically valid context for externalization and modification of children's thinking. We used an experimental procedure organized in standard and modified tasks, involving primary school children in Serbia. The results of quantitative and qualitative analyses show that the repeated question is not the unique cause of children's misleading in demonstrating to understand conservation. Other dimensions explain why children change their answers when they are tested by the two tasks we used, which offers an insight into the influence of research procedures on children's answers.  相似文献   

Crowdfunding as Donations to Entrepreneurial Firms     

Kevin J. Boudreau  Lars Bo Jeppesen  Toke Reichstein  Francesco Rullani 《Research Policy》2021,50(7):104264

The bulk of today's (“preorder-,” “reward-,” “gift-,” and “donation-based”) crowdfunding raises funds for small, private entrepreneurial ventures without granting funders private claims to the projects’ income or the ability to guarantee the realization and delivery of project outcomes. We theorize and show empirically – via a mixed-method approach applied to a representative and remarkably informative case – that the payoff structure for crowdfunders, akin to a public good contribution problem, leads to the tangible value of main project outputs exerting little influence on contributions to crowdfunding. This then raises the question of which funder motivations fund seekers may have to address to crowdfund their projects. We demonstrate the especially large role of non-pecuniary motivations and pinpoint three particular motivations that profit-seeking entrepreneurs may stimulate to be financed through crowdfunding. The findings hold important implications for entrepreneurs’ crowdfunding strategies, platform design, and our understanding of how this funding institution works in general. The study also adds to emerging research on the implications of the public good nature of crowdfunding.  相似文献   

Data-driven estimates of global nitrous oxide emissions from croplands     

Qihui Wang  Feng Zhou  Ziyin Shang  Philippe Ciais  Wilfried Winiwarter  Robert B Jackson  Francesco N Tubiello  Greet Janssens-Maenhout  Hanqin Tian  Xiaoqing Cui  Josep G Canadell  Shilong Piao  Shu Tao 《国家科学评论(英文版)》2020,7(2):441

Croplands are the single largest anthropogenic source of nitrous oxide (N₂O) globally, yet their estimates remain difficult to verify when using Tier 1 and 3 methods of the Intergovernmental Panel on Climate Change (IPCC). Here, we re-evaluate global cropland-N₂O emissions in 1961–2014, using N-rate-dependent emission factors (EFs) upscaled from 1206 field observations in 180 global distributed sites and high-resolution N inputs disaggregated from sub-national surveys covering 15593 administrative units. Our results confirm IPCC Tier 1 default EFs for upland crops in 1990–2014, but give a ∼15% lower EF in 1961–1989 and a ∼67% larger EF for paddy rice over the full period. Associated emissions (0.82 ± 0.34 Tg N yr^–1) are probably one-quarter lower than IPCC Tier 1 global inventories but close to Tier 3 estimates. The use of survey-based gridded N-input data contributes 58% of this emission reduction, the rest being explained by the use of observation-based non-linear EFs. We conclude that upscaling N₂O emissions from site-level observations to global croplands provides a new benchmark for constraining IPCC Tier 1 and 3 methods. The detailed spatial distribution of emission data is expected to inform advancement towards more realistic and effective mitigation pathways.  相似文献   

Recent advances in swollen-state NMR spectroscopy for the study of drying oils     

Giacomo Cipriani  Antonella Salvini  Luigi Dei  Azzurra Macherelli  Francesco Saverio Cecchi  Carlo Giannelli 《Journal of Cultural Heritage》2009,10(3):388-395

The cross-linking processes of three drying oils (poppy, linseed, walnut), a class of organic compounds very important in the field of artworks, were studied by means of ¹H-NMR spectroscopy, following the change of the protons signals when oils are heated at 60 °C in the presence of air or nitrogen gas. This preliminary information is particularly important to identify the presence of drying oils within a solid painting film. We demonstrated that it was possible to study these films by swollen-state NMR, an innovative spectroscopy method that can directly analyze very small semisolid samples instead of solutions. The main advantages of this method are the short time of analysis, the possibility to analyze samples without any preliminary treatment, and the small quantity of the sample required. Therefore, swollen-state NMR technique was used to characterize three real painting films: in this way, we succeeded in recognizing in real paintings specimens the presence of drying oils employed as binders, avoiding any interferences due to other organic compounds acting as binding agents, like waxes or egg-yolk media.  相似文献   

Control-based Connection Admission Control and Downlink Congestion Control procedures for satellite networks     

Francesco Delli Priscoli  Antonio Pietrabissa   《Journal of The Franklin Institute》2009,346(9):923-944

This paper focuses on the resource management procedures for a geostationary (GEO) satellite system. The objective of these procedures is the efficient exploitation of the link resources, while assuring the agreed Quality of Service to the traffic entering the satellite network. The main novelties are (i) the integration between Connection Admission Control and Downlink Congestion Control procedures, and (ii) the original adaptation of Kalman filtering theory to cope with these procedures. The proposed solution is validated by simulations.  相似文献   

Cultural practices in Italian family conversations: Verbal conflict between parents and preadolescents     

Francesco Arcidiacono  Clotilde Pontecorvo 《European Journal of Psychology of Education - EJPE》2009,24(1):97-117

This work studies verbal conflict between parents and preadolescents through analysis of family dinnertime conversations. We move from the assumption that verbal conflict is an educational instrument of interaction and a tool of socialization. The aim of the research is to analyze the participants' strategies in situations of conflict and to highlight the relations between parents and preadolescents in these specific situations. The data collection methodology is mainly ethnographical: videotape recordings of Italian middle class family dinners (the families were selected as being dual career ones with two children) were fully transcribed and codified following the approach of Conversation Analysis. The results of the quantitative (by the use of the log-linear models) and qualitative analyses confirm the importance of verbal conflict in family context as a particular cultural strategy of relationships between parents and preadolescents. The analytical data underline the relations between different aspects of conflict and the pragmatic implications for all family members at dinnertime conversations.  相似文献   

The effect of increasing written approval on Italian students’ academic performance in higher education     

Francesco Sulla  Dolores Rollo  Roberto Cattivelli  Alex Harrop 《Educational Psychology in Practice》2018,34(3):262-271

Increasing teacher verbal approval has been shown to produce both increased pupil “on-task” behaviour and academic achievement. The present study aimed to address gaps in current knowledge about the effect of different kinds of teacher approval, other than verbal approval, on students’ performance. An exploratory study, followed by an experimental study, was conducted with Italian undergraduate psychology students in order to investigate the effect of written approval on their academic performance. The results indicate that, whilst there is some suggestion that students appreciated receiving increased written approval comments on their work, the receipt of such comments was accompanied by poorer academic performance than that of a control group. Possible explanations are presented.  相似文献   

The educational psychology section of the Institute of psychology of the National Research Council (CNR,Roma)     

Francesco Tonucci 《European Journal of Psychology of Education - EJPE》1986,1(1):101-106

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