This paper deals with the leader-following consensus problem of multi-agent systems with the consideration that each agent can only transmit its position state to the neighbors at irregular discrete sampling times. In the proposed algorithm, a continuous-discrete time observer is designed for the continuous estimation of both position and velocity from the discrete position information of the neighbors. These estimated states are then used for designing a continuous control law which solves the leader-following consensus problem. Moreover, the dynamics of the leader is not fixed and can be controlled through an external input. The stability analysis has been carried out by employing the Lyapunov approach which provides sufficient conditions to tune the parameters according to the maximum allowable sampling period. The developed algorithm has been simulated and then tested on an actual multi-robot system consisting of three differential drive wheeled robots. Both simulation and hardware results validate the effectiveness of the control algorithm. 相似文献
Minerva - Project funding rarely demands much change on behalf of the recipient. In contrast, cross-sectoral mobility funding requires recipients to change their environment and often some aspects... 相似文献
Children with dyslexia are believed to have very poor phonological skills for which they compensate, to some extent, through relatively well-developed knowledge of letter patterns. We tested this view in Study 1 by comparing 25 dyslexic children and 25 younger normal children, chosen so that both groups performed, on average, at a second-grade spelling level. Phonological skill was assessed using phoneme counting and nonword spelling tasks. Knowledge of legal and illegal letter patterns was tested using a spelling choice task. The dyslexic children and the younger nondyslexic children performed similarly on all the tasks, and they had difficulty, for the most part, with the same linguistic structures. Supporting the idea that older dyslexics spellings are quite similar to those of typical beginners, we found in Study 2 that experienced teachers could not differentiate between the two groups based on their spellings. 相似文献
For years, a popular explanation for women choosing to abandon studies in science, technology, engineering, and mathematics (STEM) has been their lack of aptitude. This study challenged that notion by integrating theories of cognitive style, academic emotion, self-efficacy, and motivation to explain students’ academic achievement and perseverance in STEM when transitioning to college. A sample of 1597 high school and junior college students participated. Exploratory and confirmatory factor analyses were first conducted to validate a reduced version of the cognitive style questionnaire. Structural equation modeling revealed that the cognitive style known as systemizing indirectly predicted STEM achievement and persistence by way of intrinsic motivation, learning anxiety, and self-efficacy, providing a new perspective for re-examining the gender gap in STEM.
The aims of this study were to identify differences between the sexes in extra-curricular participation in sports and to determine its association with body fat and socio-demographic factors in Spanish adolescents. A total of 2165 adolescents (1124 males and 1041 females) aged 13.0-18.5 years from the AVENA Study participated. Participants filled in an ad hoc questionnaire for extra-curricular participation in sports, which was the dependent variable. Independent variables were: age, percent body fat, and father's and mother's educational level and occupation. Chi-square tests and logistic regression were applied. Bivariate analysis showed for male adolescents that age and father's occupation were related to extra-curricular participation in sports. In addition, body fat and mother's education and occupation (all P?0.05) were related to extra-curricular participation of in sports for female adolescents. Logistic regression analysis showed that the likelihood of involvement in extra-curricular participation in sports was 5.3-fold (3.86-7.38) higher for males than females. Age and father's education in both males and females were independently associated with extra-curricular participation in sports. In summary, Spanish male adolescents were shown to engage in more extra-curricular sports than females. In addition, age and father's education (in both sexes) were associated with the participation of their offspring in extra-curricular sports during adolescence. 相似文献
Two studies examined the relationships between measures of intelligence, personality and divergent thinking (DT) in student samples. Study one investigated the incremental validity of measures of IQ and fluid intelligence with the Big Five Personality Inventory with regards to DT. Significant relationships of DT to fluid intelligence, Extraversion and Disagreeableness were observed. Study two investigated the incremental validity of measures of fluid and crystallised intelligence (as assessed by a test of general knowledge) with the Big Five Personality Inventory with regards to DT. Hierarchical regression analyses revealed a significant relationship between crystallised intelligence and DT. The nature of the relationships of IQ, fluid and crystallised intelligence, in addition to personality traits to tests of DT were considered. 相似文献
The purpose of the present study was to explore the themes that counselor education doctoral students perceive as influencing their experience. The results of an exploratory qualitative study in which counselor education doctoral students provided their perceptions of what helped or hindered their progress are presented. Themes identified as both positively and negatively influencing their experiences were departmental culture, mentoring, academics, support systems, and personal issues. Recommendations are provided for counselor educators to consider in their work with doctoral students. 相似文献
ObjectiveTo examine the prevalence, characteristics and risk factors for child maltreatment among opioid-dependent persons compared to a community sample of similar social disadvantage.MethodThe study employed a case-control design. Cases had a history of opioid pharmacotherapy. Controls were frequency matched to cases with regard to age, sex and unemployment and were restricted to those with a lifetime opioid use of less than five times. The interview covered child maltreatment, family environment, drug use and psychiatric history.ResultsThis study found a high prevalence of child maltreatment among both cases and controls. Despite the elevated prevalence among controls, opioid-dependent males had a higher prevalence of physical and emotional abuse; female cases had a higher prevalence and greater severity of sexual abuse. The prevalence of neglect was similar for both groups. Early parental separation was more prevalent among female cases compared to female controls; otherwise the prevalence of the risk factors was comparable for both groups. The risk factors significantly associated with child maltreatment were also similar for both cases and controls.ConclusionsGiven the documented association between child maltreatment and adult mental disorder, child maltreatment may be an important antecedent of current psychological distress in persons presenting to treatment for opioid dependence. Apart from a possible association between early parental separation and sexual abuse among female cases, the increased prevalence of child maltreatment associated with opioid dependence did not appear to be related to differences in early childhood risk factors considered in this paper. Other risk factors may be more pertinent for those with opioid dependence.Practice implicationsThe high prevalence of child maltreatment among the opioid-dependent sample has implications for the assessment and treatment of clients presenting with opioid dependence. Assessment of child maltreatment history could help inform the development of individual treatment plans to better address those factors contributing to the development and maintenance of opioid dependence. Specifically, management of co-morbid mental disorder associated with child maltreatment could be the focus of relapse prevention programmes and also have a positive influence on treatment retention. 相似文献