Non-centralized control for flow-based distribution networks: A game-theoretical insight     

Julian Barreiro-Gomez  Carlos Ocampo-Martinez  Nicanor Quijano  José M. Maestre 《Journal of The Franklin Institute》2017,354(14):5771-5796

This paper solves a data-driven control problem for a flow-based distribution network with two objectives: a resource allocation and a fair distribution of costs. These objectives represent both cooperation and competition directions. It is proposed a solution that combines either a centralized or distributed cooperative game approach using the Shapley value to determine a proper partitioning of the system and a fair communication cost distribution. On the other hand, a decentralized non-cooperative game approach computing the Nash equilibrium is used to achieve the control objective of the resource allocation under a non-complete information topology. Furthermore, an invariant-set property is presented and the closed-loop system stability is analyzed for the non-cooperative game approach. Another contribution regarding the cooperative game approach is an alternative way to compute the Shapley value for the proposed specific characteristic function. Unlike the classical cooperative-games approach, which has a limited application due to the combinatorial explosion issues, the alternative method allows calculating the Shapley value in polynomial time and hence can be applied to large-scale problems.  相似文献   

Synthetic hybrid indicators based on scientific collaboration to quantify and evaluate individual research results     

Antonio Perianes-Rodríguez  Zaida Chinchilla-Rodríguez  Benjamín Vargas-Quesada  Carlos Olmeda Gómez  Félix Moya-Anegón 《Journal of Informetrics》2009,3(2):91-101

Governmental initiatives around scientific policy have progressively raised collaboration to priority status. In this context, a need has arisen to broaden the traditional approach to the analysis and study of research results by descending to the group or even the individual scale and supplementing the output-, productivity-, visibility- and impact-based focus with new measures that emphasize collaboration from the vantage of structural analysis. To this end, the present paper proposes new hybrid indicators for the analysis and evaluation of individual research results, popularity and prestige, that combine bibliometric and structural aspects. A case study was conducted of the nine most productive departments in Carlos III University of Madrid. The findings showed hybridization to be a tool sensitive to traditional indicators, but also to the new demands of modern science as a self-organized system of interaction among individuals, furnishing information on researchers’ environments and the behaviour and attitudes adopted within those environments.  相似文献   

Cleaning the slate? School choice and educational outcomes in Spain     

Cecilia Albert  Carlos García-Serrano 《Higher Education》2010,60(6):559-582

Using data from a nation-wide survey on Spanish workers, this paper examines two issues: the determinants of school choice (distinguishing between public and private schools) and the influence of school type on the individual’s educational attainment. For that, bivariate probit models are estimated. The analysis is carried out separately by gender and birth cohort. We find that individuals who have attended a private school come from households with higher socio-cultural level and that having attended a private school does not raise the probability of reaching a higher degree, once potential endogeneity of school choice and educational outcomes are taken into account. However, the latter result depends on the instrumental variable used for observed school type in models of demand for higher education.  相似文献   

Alternative assessment of knee joint muscle balance of soccer players through total work-based hamstring: quadriceps ratios     

Felipe Minozzo  Carlos Leonardo Figueiredo Machado  Eurico Nestor Wilhelm  Rafael Grazioli  Ronei Silveira Pinto 《European Journal of Sport Science》2018,18(10):1398-1404

Isokinetic hamstring-to-quadriceps (H:Q) ratios are frequently used to assess knee muscle strength imbalances and risk of injuries/re-injuries. The use of peak torque (PT) or total work (TW) to estimate joint stability may lead to different results because of the differences between these two neuromuscular variables. Thus, the current study aimed to compare the conventional and functional H:Q ratios calculated by PT and TW. Ninety-three male professional soccer players from Brazilian first division teams performed isokinetic concentric and eccentric contractions of the quadriceps and the hamstrings at 60°/s. Muscle strength balance was calculated using the conventional torque ratio (CTR) and conventional work ratio (CWR), functional torque ratio (FTR) and functional work ratio (FWR) were highly and moderately correlated between them (r?=?0.83 and r?=?0.73, respectively). The Wilcoxon statistical test revealed significant differences between CTR and CWR, as well as FTR and FWR (p?T-test demonstrated significant differences in mean CTR–CWR and FTR–FWR, whereas Bland–Altman plots showed non-consistent bias. In addition, the chi-square test demonstrated significant differences between players below the conventional reference values and functional reference values (p?相似文献   

Effects of inspiratory muscle training in professional women football players: a randomized sham-controlled trial     

Bruno Archiza  Daniela Kuguimoto Andaku  Flávia Cristina Rossi Caruso  José Carlos Bonjorno Jr.  Cláudio Ricardo de Oliveira  Paula Angélica Ricci 《Journal of sports sciences》2018,36(7):771-780

This study was conducted to determine the effects of inspiratory muscle training (IMT) on respiratory and peripheral muscles oxygenation during a maximal exercise tolerance test and on repeated-sprint ability (RSA) performance in professional women football players. Eighteen athletes were randomly assigned to one of the following groups: SHAM (n = 8) or IMT (n = 10). After a maximal incremental exercise test, all participants performed (on a different day) a time-to-exhaustion (Tlim) test. Peripheral and respiratory muscles oxygenation by near-infrared spectroscopy, breath-by-breath ventilatory and metabolic variables, and blood lactate concentration were measured. The RSA test was performed on a grass field. After a 6 week intervention, all athletes were reevaluated. Both groups showed increases in inspiratory muscles strength, exercise tolerance and RSA performance, however only the IMT group presented lower deoxyhemoglobin and total hemoglobin blood concentrations on intercostal muscles concomitantly to an increased oxyhemoglobin and total hemoglobin blood concentrations on vastus lateralis muscle during Tlim. In conclusion, these results may indicate the potential role of IMT to attenuate inspiratory muscles metaboreflex and consequently improve oxygen and blood supply to limb muscles during high-intensity exercise, with a potential impact on inspiratory muscle strength, exercise tolerance and sprints performance in professional women football players.  相似文献   

Energy,macronutrient and water intake during a mountain ultramarathon event: The influence of distance     

Sonia Martinez  Antoni Aguilo  Lluis Rodas  Leticia Lozano  Carlos Moreno 《Journal of sports sciences》2018,36(3):333-339

Adequate dietary strategies are essential for the successful participation in ultra-endurance races. The aim of this study was to evaluate and compare the energy and water intakes of participants during three different mountain ultra-endurance runs. The study took place at the “Ultra Mallorca Serra de Tramuntana” (Mallorca, Spain), an ultra-endurance mountain event with runners participating either in a 44-km (Marathon, n = 51), a 67-km (Trail, n = 109) or a 112-km (Ultra, n = 53) run competition. Participants in the study answered a questionnaire focused on the nutritional intake within an hour after finishing the competition. Mean energy intake during the competitions was 183 kcal · h^¯1, with an average carbohydrate intake of 31 g · h^¯1 (52.1% of participants consumed less than 30 g · h^¯1). No significant differences between competitions were found in these parameters. However, a higher percentage of energy from lipids in participants in the Trail and the Ultra was found (P = 0.034). Furthermore, significant differences were observed in water intake per hour of competition (P = 0.039), with the lowest value for the intake during the Ultra competition. In conclusion, the majority of the participants in the study present low carbohydrate intakes. However, fluid intake seems to be adequate. Different distances did not significantly influence the participants’ nutritional strategies.  相似文献   

The use of hypermedia in collaborative learning. An approach to the problem of complex systems in the teaching of urban planning / El uso de hipermedia en el aprendizaje colaborativo. Una aproximación al problema de los sistemas complejos en la docencia del urbanismo     

Carlos Rosa-Jimenez  Maria-José Marquez-Ballesteros  Nuria Nebot 《Cultura y Educación》2018,30(2):414-432

The counterpart to the open access to information facilitated by the Internet is the problem of the over-saturation of data and sources. A collaborative model of hypermedia is proposed as a pedagogical approach to the teaching of urban planning in which students organize and construct information from the possibilities provided by hypertext language. The methodology is structured in three phases: organization when searching for information; presentation of information using hypermedia; and assessment of the work. The results show that organization of information in the form of websites obtained the highest scores, although collaborative assessment should be restricted to subjective aspects of communication, while objective aspects should be assessed by the teacher and by groups of experts.  相似文献   

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome     

Carlos González-Haro  Pedro A. Galilea  Jesús F. Escanero 《Journal of sports sciences》2013,31(6):591-601

Abstract

The primary objective of this study was to examine the relationship between heart rate intensity and pedometer step counts in adolescents. To determine cardiorespiratory fitness, 106 participants (47 boys, 59 girls, mean age 14.2 years, s = 0.8) completed the Queen's College Step Test and were classified as having low, moderate or high cardiorespiratory fitness. Adolescents also completed a 10-min treadmill trial while wearing a pedometer and heart rate monitor. The participants were instructed to maintain their heart rate between 65 and 75% of their maximum heart rate while running or walking on a treadmill. A heart rate of 65–75% maximum was associated with 146 steps per minute (s = 22) in boys and 137 steps per minute (s = 22) in girls. Results of analysis of variance indicated that there was a main effect for level of fitness (F _2,102 = 9.36, P < 0.001). The correlation between mean steps per minute and estimated maximum oxygen consumption was statistically significant (r = 0.44, P < 0.001). The results from this study suggest that a step rate of 130 steps per minute is equal to 65–75% maximum heart rate in low-fit adolescents and achieving 130 steps per minute could be used as an initial goal to improve fitness.  相似文献   

Determinants and patterns of physical activity practice among Spanish university students     

Dora Romaguera  Pedro Tauler  Miquel Bennasar  Jordi Pericas  Carlos Moreno  Sonia Martinez 《Journal of sports sciences》2013,31(9):989-997

Abstract

The purpose of the present study was to investigate the socio-demographic and lifestyle determinants of physical activity practice, as well as the motivations for being or not being physically active in Spanish university students. A representative sample of students from a Spanish university (n = 2,051; 42.1% males; mean age 21.9, s = 4.8 years) participated in the present cross-sectional study. A questionnaire including questions regarding lifestyle, dietary habits, parents' characteristics, and physical activity habits was administered to the students. The socio-demographic and lifestyle determinants of physical activity practice were assessed using multivariable logistic regression. 68.4% of men and 48.4% of women reported to practise physical activity in the present sample. Those who practised physical activity consumed more fruits and were less likely to be smokers compared to non-physically active students. Also, physically inactive men spent more time in front of the computer and physically inactive women spent more time in front of the TV and were more likely to be frequent alcohol consumers. Maternal educational level and maternal physical activity habits were also important determinants of physical activity practice among men and women respectively. In conclusion, physically active students tended to engage in other healthy habits in the present population, suggesting the clustering of healthy or unhealthy lifestyle factors among specific subgroups.  相似文献   

Tensiomyography parameters and jumping and sprinting performance in Brazilian elite soccer players     

Saulo Gil  Irineu Loturco  Valmor Tricoli  Carlos Ugrinowitsch  Ronaldo Kobal  Cesar Cavinato Cal Abad 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):340-350

Tensiomyography has been suggested as an indirect marker of muscle stiffness, which is associated with strength/power performance. Therefore, it is reasonable to suggest that tensiomyography parameters could be associated with power-related motor tasks. The purpose of this study was to investigate the association between tensiomyography parameters (from rectus and biceps femoris) and jumping and sprinting abilities in elite soccer players. In addition, we used tensiomyography parameters to compare the lateral symmetry between dominant and non-dominant legs. Twenty elite soccer players (age: 23.3 ± 4.8 years; height: 183.5 ± 6.6 cm; weight: 77.8 ± 7.5 kg) volunteered to participate in the study. Significant moderate negative correlations between biceps femoris displacement and contact time (r = –0.5, p = 0.03), rectus femoris displacement and contact time (r = –0.51, p = 0.02), and a significant moderate correlation between biceps femoris displacement and reactive strength index (r = 0.5, p = 0.03) were found. There were no correlations between tensiomyography parameters and power-related motor tasks. In addition, no differences in tensiomyography parameters between dominant and non-dominant legs were found. Our data suggest that tensiomyography parameters are not associated with power-related motor tasks performance in elite soccer players.  相似文献