Stability of switching linear systems with switching signals driven by stochastic processes

This paper presents conditions to assure the exponential stability in probability for autonomous switching linear systems. The switching signal acting on the autonomous system produces intervals that follow independent, identically distributed stochastic processes—the stability then follows by verifying simple-to-check linear matrix inequalities.     

Complementing subjective with objective data in analysing expertise: A machine-learning approach applied to badminton

ABSTRACT

This study aimed to assess which combination of subjective and empirical data might help to identify the expertise level. A group of 10 expert coaches classified 40 participants in 5 different expertise groups based on the video footage of the rallies. The expertise levels were determined using a typology based on a continuum of 5 conative stages: (1) structural, (2) functional, (3) technical, (4) contextual, and (5) expertise. The video allowed empirical measurement of the duration of the rallies, and tri-axial accelerometers measured the intensity of the player’s involvement. A principal component analysis showed that two dimensions explained 54.9% of the total variance in the data and that conative stage and empirical parameters during rallies (duration, intensity of the game) were correlated with axis 1, whereas duration and acceleration data between rallies were correlated with axis 2. A random forest algorithm showed that among the parameters considered, acceleration, duration of the rallies, and time between rallies could predict conative stages with a prediction accuracy above possibility.

This study suggests that performance analysis benefits from the confrontation of subjective and objective data in order to design training plans according to the expertise level of the participants.     

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.     

Religiosity,the headscarf,and education in Turkey: an analysis of 1988 data and current implications

Previous research highlights the continuing relevance of family culture in explaining educational inequalities in Turkey, especially patriarchal beliefs and practices that discourage investment in the education of girls. We extend that research by introducing two much‐debated, but empirically untested, aspects of family culture – parental religiosity and headscarf preferences. An analysis of a nationally representative sample of 15–19 year olds in 1988 shows that while religiosity had no significant effect on educational attainment, children who lived in families whose fathers expected them to wear a headscarf in public had lower educational attainment, especially girls. The large negative headscarf effect suggests that the government ban on headscarves in schools may be an obstacle to eliminating gender inequality in education. The results are discussed in light of recent trends in Turkish society.     

Chebyshev polynomial solutions of systems of higher-order linear Fredholm-Volterra integro-differential equations

A Chebyshev collocation method, an expansion method, has been proposed in order to solve the systems of higher-order linear integro-differential equations. This method transforms the IDE system and the given conditions into the matrix equations via Chebyshev collocation points. By merging these results, a new system which corresponds to a system of linear algebraic equations is obtained. The solution of this system yields the Chebyshev coefficients of the solution function. Some numerical results are also given to illustrate the efficiency of the method. Moreover, this method is valid for the systems of differential and integral equations.     

The Relative Efficiency of Departments at a Turkish Engineering College: A Data Envelopment Analysis

In this study, Data Envelopment Analysis is used to measure relative efficiencies of academic departments of an engineering college. Input and output criteria are determined and measured utilizing the academic personnel performance measurement scheme of the College. New measures are developed to compare departments of different disciplines. The discriminating power of the measurement models is improved by restricting criteria weights directly and by using a multiple criteria decision making approach. Sensitivity of the results to exclusion of a criterion and changes in relative importance of the criteria is analyzed. Evaluation of the results jointly by the college administration and the departments is explained for a successful efficiency improvement mechanism.     

Going to action? A literature review on educational proposals in formal Environmental Education

The current state of the planet’s environmental deterioration calls for formal educational contexts to implement effective environmental proposals which nurture action competence. The aim of this paper is to examine the educational proposals in formal contexts that have been published in the two research journals of greatest impact on Environmental Education during the period 2008–2013, and to analyse how they contribute to the development of action competence. Special attention is paid to research (i) based on real participation by students; (ii) promotes reflection on the complexity of environmental issues; (iii) facilitates critical thinking; (iv) encourages autonomous and responsible decision-making and (v) involves communities. Our results show that these approaches can help improve the development of action-focused environmental education and bring to light a series of challenges for future research.     

The role of perceived classroom goal structures,self-efficacy,and engagement in student science achievement

Background: Numerous studies have been conducted to investigate the factors related to science achievement. In these studies, the classroom goal structure perceptions, engagement, and self-efficacy of the students have emerged as important factors to be examined in relation to students’ science achievement.

Purpose: This study examines the relationships between classroom goal structure perception variables (motivating tasks, autonomy support, and mastery evaluation), engagement (behavioral, emotional, cognitive, and agentic engagement), self-efficacy, and science achievement.

Sample: The study participants included 744 seventh-grade students from 9 public schools in two districts of Gaziantep in Turkey.

Design and methods: Data were collected through the administration of four instruments: Survey of Classroom Goals Structures, Engagement Questionnaire, Motivated Strategies for Learning Questionnaire, and Science Achievement Test. The obtained data were subjected to path analysis to test the proposed model.

Results: Students’ perceptions of classroom goal structures (i.e. motivating tasks, autonomy support, and mastery evaluation) were found to be significant predictors of their self-efficacy. Autonomy support was observed to be positively linked to all aspects of engagement, while motivating tasks were found to be related only to cognitive engagement. In addition, mastery evaluation was shown to be positively linked to engagement variables, except for cognitive engagement, and self-efficacy and engagement (i.e. behavioral, emotional, and cognitive engagement) were observed to be significant predictors of science achievement. Finally, results revealed reciprocal relations among engagement variables, except for agentic engagement.

Conclusions: Students who perceive mastery goal structures tend to show higher levels of engagement and self-efficacy in science classes. The study found that students who have high self-efficacy and who are behaviorally, emotionally, and cognitively engaged are more successful in science classes. Accordingly, it is recommended that science teachers utilize inquiry-based and hands-on science activities in science classes and focus on the personal improvement of the students. Furthermore, it is also recommended that they provide students with opportunities to make their own choices and decisions and to control their own actions in science classes.