Feedback factorizing control of 3-D transfer functions via a canonical state-space model

The problem factorizing (separating) the transfer function of a given SISO 3-D discrete system, ie of a system depending on three independent variables, is considered. The 3-D system is assumed to be available in its transfer function representation, which is converted to a canonical state-space model by a simple inspection procedure. Then applying state-feedback to this canonical model we choose the feedback matrix gain (under certain conditions) such that the transfer function of the closed-loop system has the desireed factorized form, ie a product of three 1-D transfer functions each one being dependent on a single variable. The method is illustrated by a nontrivial numerical example.     

‘Children at our school are integrated. No one sticks out’: Greek‐Cypriot teachers’ perceptions of integration of immigrant children in Cyprus

Increasingly social scientists, including education theorists, find themselves having to fight an almost invisible racism that is masked by the racist undertones of the dominant discourse and practice of colorblindness. A continuous emphasis on colorblindness gives precedence to the role of race, diverting attention away from other forms of discrimination which can become the basis for exclusion. I would argue that for such acts of marginalization, difference‐blindness may have more explanatory power. This paper discusses Greek‐Cypriot teachers’ perceptions of the integration of immigrant children in a Greek‐Cypriot public primary school through the framework of difference‐blindness. The discussion shows that despite their good intentions, teachers utilized a difference‐blind ideology to rationalize practices of social exclusion of non‐Cypriot students in what was considered an ‘integrated’ school environment.     

Has family involvement migrated into higher education? An investigation of how administrative staff document the phenomenon in students’ university experiences in Cyprus

Families have been getting more and more involved in their children’s education. This paper presents findings of a study investigating family involvement in their members’ undergraduate studies attending a state (non-fee-paying) and a private (fee-paying) university in Cyprus. The data presented in the paper were collected via online logs completed by administrative personnel in the two universities documenting incidents of family involvement. The data analysis demonstrates how similarly the phenomenon manifests in both universities and suggests that where the two universities differ is more in the intensity of the various modes of family involvement. It also projects students’ desires and encouragement of their family’s involvement and their families’ intervention to protect or guide them. The findings of the study are discussed in view of cultural and societal norms and changes about parenthood and the relationship between families and their university age members in a marketized higher education context.     

Understanding Nutrition: A Study of Greek Primary School Children Dietary Habits,Before and After Classroom Nutrition Intervention

The purpose of this study was first to assess and then to improve the diet of Greek primary school children teaching them healthy dietary habits and instructing them to face critically advertisements and media projected dietary models using a program which included intervention on cognitive, emotional, and social level. The results show that our intervention was more effective on the cognitive level and in particular on children's ability to estimate the dietary value of different kinds of food. However, their food preferences were not affected significantly, suggesting that these are more resistant to change since they are already consolidated and, therefore, need longer intervention.     

Sprint mechanical differences at maximal running speed: Effects of performance level

ABSTRACT

As the effect of performance level on sprinting mechanics has not been fully studied, we examined mechanical differences at maximal running speed (MRS) over a straight-line 35 m sprint amongst sprinters of different performance levels. Fifty male track and field sprinters, divided in Slow, Medium and Fast groups (MRS: 7.67 ± 0.27 m?s^?1, 8.44 ± 0.22 m?s^?1, and 9.37 ± 0.41 m?s^?1, respectively) were tested. A high-speed camera (250 Hz) recorded a full stride in the sagittal plane at 30–35 m. MRS was higher (p < 0.05) in Fast vs. Medium (+11.0%) and Slow (+22.1%) as well as in Medium vs. Slow (+10.0%). Twelve, eight and seven out of 21 variables significantly distinguished Fast from Slow, Fast from Medium and Medium from Slow sprinters, respectively. Propulsive phase was signi?cantly shorter in Fast vs. Medium (?17.5%) and Slow (?29.4%) as well as in Medium vs. Slow (?14.4%). Fast sprinters had significantly higher vertical and leg stiffness values than Medium (+44.1% and +18.1%, respectively) and Slow (+25.4% and +22.0%, respectively). MRS at 30–35 m increased with performance level during a 35-m sprint and was achieved through shorter contact time, longer step length, faster step rate, and higher vertical and leg stiffness.     

The autistic spectrum. Characteristics,causes and practical issues

Recent inclusive policy directives and advice offered to schools strongly recommend special/support teachers to expand their role and extend their duties. In light of this, we investigated how Greek secondary special/support teachers perceive and experience their role, work profile and the challenges they encounter. Qualitative analysis revealed that participants perceived their role as multidimensional, but focused on its reactive rather than proactive aspect. Role ambiguity, confusing expectations, lack of collaboration and the devalued position within the teaching staff of the school were some of the complexities reported. The findings are discussed in terms of their implications for advancing teachers’ professional development and promoting inclusive practices within secondary education schools.     

Nearest-biclusters collaborative filtering based on constant and coherent values

Collaborative Filtering (CF) Systems have been studied extensively for more than a decade to confront the “information overload” problem. Nearest-neighbor CF is based either on similarities between users or between items, to form a neighborhood of users or items, respectively. Recent research has tried to combine the two aforementioned approaches to improve effectiveness. Traditional clustering approaches (k-means or hierarchical clustering) has been also used to speed up the recommendation process. In this paper, we use biclustering to disclose this duality between users and items, by grouping them in both dimensions simultaneously. We propose a novel nearest-biclusters algorithm, which uses a new similarity measure that achieves partial matching of users’ preferences. We apply nearest-biclusters in combination with two different types of biclustering algorithms—Bimax and xMotif—for constant and coherent biclustering, respectively. Extensive performance evaluation results in three real-life data sets are provided, which show that the proposed method improves substantially the performance of the CF process.

Rating students’ problem behaviour: the role of teachers’ individual characteristics

This study examined the role of teachers’ personal characteristics and mental health status on their frequency ratings of student problem behaviour. A sample of 121 primary school teachers were asked to rate the frequency of a student’s behavioural problems, and to self-report their personality traits, psychopathology symptoms and burnout. Overall, the results revealed that teachers’ ratings were significantly predicted by their psychopathology symptoms and to a lesser extent by their personality traits and burnout levels. Student and teacher demographic characteristics were also predictive of teacher ratings. Since teachers are among the primary informants of students’ mental health, the results of this study pose the need to take into consideration teachers’ individual characteristics, when their ratings are critically evaluated during a student’s referral process.     

Effect of body composition on redox homeostasis at rest and in response to exercise: The case of underfat women

Underfat individuals have been neglected as a malnourished population in terms of redox homeostasis. The aim of the present study was to evaluate the effect of body composition on redox homeostasis at rest and in response to exercise. Underfat, lean and overfat women, classified according to their BMI and body fat percentage, participated in the study and were subjected to an acute session of eccentric exercise. With regard to muscle function and damage, a significant group × time interaction was found for range of motion (P < .01), isometric peak torque at 90° (P < .01), delayed onset muscle soreness (P < .01) and creatine kinase (P < .05), with the lean group generally exhibiting faster recovery compared to the underfat and overfat groups. With regard to redox homeostasis, a significant group × time interaction was found for F₂-isoprostanes, protein carbonyls and glutathione (P < .01 for all biomarkers), with the underfat and overfat groups exhibiting increased resting oxidative stress levels and lower exercise-induced reactive species production . In conclusively, our data underline the importance of normal body composition for redox homeostasis, since underfat and overfat women demonstrate a similar pattern of redox disturbances both at rest and in response to exercise.     

Seismic behavior of diaphragm-through connections of concrete-filled square steel tubular columns and H-shaped steel beams

Based on the introductions of a type of diaphragm-through connection between concrete-filled square steel tubular columns (CFSSTCs) and H-shaped steel beams,a finite element model of the connection is developed and used to investigate the seismic behavior of the connection.The results of the finite element model are validated by a set of cyclic loading tests.The cyclic loading tests and the finite element analyses indicate that the failure mode of the suggested connections is plastic hinge at the beam with inelastic rotation angle exceeding 0.04 rad.The suggested connections have sufficient strength,plastic deformation and energy dissipation capacity to be used in composite moment frames as beam-to-column rigid connections.