Nonlinear modeling and robust LMI fuzzy control of overhead crane systems

Overhead cranes are widely used structures for lifting and conveying heavy loads. The development of feedback control systems for such equipment is important due to the large number of potential applications and advantages over manual operation concerning stability and robustness. This paper aims to represent the key nonlinear dynamics of crane systems by means of a state-space fuzzy model with compact rule-base structure. The fuzzy model is useful to assist the design of a fuzzy controller based on the concept of parallel compensation. A well-posed conservative linear-matrix-inequality (LMI) feasibility problem is formulated so that a solution guarantees closed-loop Lyapunov stability, bounded control inputs, quick positioning of the supporting cart, and suppression of load oscillations and collisions. The fuzzy controller is composed by rules with linear control laws derived from local state-space models. The controller warrants asymptotic convergence of the states. Due to the nonlinear nature of the fuzzy model and controller, Jacobian linearization is avoided. The proposed fuzzy control approach for cranes has shown to be more effective and robust than an optimal quadratic controller, and able to move cargo smoothly and safely to a destination. Particularly, constrained and smoother control inputs avoid actuator saturation, and tend to increase its lifetime. Laboratory experiments using the LMI fuzzy controller and actual data validates the approach for cranes in actual scenario.     

Musculoskeletal anatomy knowledge in Australian chiropractors

Anatomy is a key knowledge area in chiropractic and is formally offered in the undergraduate component of chiropractic education. There is the potential for loss of anatomy knowledge before the opportunity to apply it in a clinical setting. This study aimed to determine whether chiropractic clinicians retain a level of anatomy knowledge comparable to that of chiropractic students and to compare chiropractors' self-rating of their anatomical knowledge against an objective knowledge assessment tool. A previously validated multiple-choice test was utilized to measure retention of limb musculoskeletal (MSK) knowledge in Australian chiropractors. One hundred and one registered chiropractors completed the questionnaire and responses were scored, analyzed, and compared to scores attained by undergraduate and postgraduate chiropractic students who had previously completed the same questionnaire. The results indicated that practitioners retained their anatomy knowledge, with a significantly higher total mean score than the undergraduate group [total mean score = 36.5% (±SD 13.6%); P < 0.01] but not significantly different to the postgraduate group [total mean score = 52.2% (±SD 14.1%); P = 0.74]. There was a weak positive correlation between chiropractors' self-rated knowledge and test performance scores indicating the effectiveness of this Australian chiropractic group in self-assessing their anatomy knowledge. This study found that Australian chiropractors' knowledge of MSK anatomy was retained during the transition from university to clinical practice and they accurately evaluated their own test performance.     

Teacher and parental views on inclusive education policy lending in the Czech Republic

In international education policy articulations by organisations such as the UNESCO, inclusive education is defined rather vaguely, usually in terms of human rights. Yet, national reception it is more or less taken for granted. Analyses of policy lending show that when national education traditions are not respected, the lack of clarity about the concrete form of inclusion is further augmented by resistance to a foreign import. Taking the example of the implementation of inclusive education in the Czech Republic, a secondary analysis of survey results on responses from teachers and parents is presented. This analysis contributes to a better understanding of the reactions of two groups of actors who have had only a marginal involvement in preparing the implementation of inclusion; specifically, teachers at ordinary schools and parents of pupils with special education needs. Teachers are critical of inclusion, which they regard as special care for individual pupils with special education needs. It is only in schools which have lengthy experience with integration that a transformation of the school culture and the teaching profession in the direction of greater teamwork has taken place. The imperative of inclusion coming from above is regarded more as interference with what is a spontaneous development. The view of parents to pupils with special education needs was that systemic support to inclusion was lacking. Parents are forced to be intermediaries between other actors, but often do not have enough information and are not respected by teachers as experts on their children.     

Convexity in scientific collaboration networks

Convexity in a network (graph) has been recently defined as a property of each of its subgraphs to include all shortest paths between the nodes of that subgraph. It can be measured on the scale [0, 1] with 1 being assigned to fully convex networks. The largest convex component of a graph that emerges after the removal of the least number of edges is called a convex skeleton. It is basically a tree of cliques, which has been shown to have many interesting features. In this article the notions of convexity and convex skeletons in the context of scientific collaboration networks are discussed. More specifically, we analyze the co-authorship networks of Slovenian researchers in computer science, physics, sociology, mathematics, and economics and extract convex skeletons from them. We then compare these convex skeletons with the residual graphs (remainders) in terms of collaboration frequency distributions by various parameters such as the publication year and type, co-authors’ birth year, status, gender, discipline, etc. We also show the top-ranked scientists by four basic centrality measures as calculated on the original networks and their skeletons and conclude that convex skeletons may help detect influential scholars that are hardly identifiable in the original collaboration network. As their inherent feature, convex skeletons retain the properties of collaboration networks. These include high-level structural properties but also the fact that the same authors are highlighted by centrality measures. Moreover, the most important ties and thus the most important collaborations are retained in the skeletons.     

Epistemology As Ethics In Research And Policy: The Use of Case Studies

This article examines the ethnographic case study in education in the context of policy making with particular emphasis on the practice of research and policy making. The central claim of the article is that it is impossible to establish a transcendental epistemology of the case study on instrumental rationality. Instead it argues for the notion of situated judgement that needs to be made by practitioners in context, practitioners being both researchers and policy makers. In other words, questions about the level of confidence or warrant that can be placed in different sorts of research evidence and findings cannot be answered independently of forming a view about the appropriateness of the policy culture that shapes political decision‐making. The article draws a distinction between the general, which is internal to the data as construed by a particular discipline, and the universal, which is the result of embedded human deliberation. This applies to all research findings and not only to case study, although since case study has long had to defend itself against accusations of the lack of generality, it can be a useful starting point for the discussion. This article is not meant to be yet another defence of the case study research genre, although a summary of other defences is offered. Rather it focuses on how use of the case study points to the limits of epistemology as rationality and offers a view of epistemology as ethics.     

Training and Education for Conducting Physical Education Classes in Croatia since 1875

This research analyzed the activities and events that enabled the establishment of an education and training system for physical education (PE) teachers in Croatia. The beginning of professional PE education in Croatia is related to its introduction as an obligatory subject in the elementary school curriculum of the Kingdom of Croatia-Slavonia in 1874. Most elementary school teachers did not have the knowledge needed to conduct PE classes. We recognized two parallel systems of training introduced in 1875: the first consisted of short training courses, and the second was the introduction of gymnastics as an obligatory course at teacher-training colleges. Twenty years after these obligatory PE classes were introduced to Croatian schools, Franjo Bu?ar organized and managed a two-year course for secondary school gymnastics teachers (1894–1896) after his return from a two-year educational programme at the Royal Central Gymnastic College in Stockholm (Sweden). This high school was the first for PE training not only in Croatia but also this region of Europe. In 1959, the first Croatian institution for PE education was established: the High School for Physical Culture in Zagreb.     

Pupils’ humour directed at teachers: its types and functions

Based on an analysis of 137 texts written by pupils, this paper examines pupils’ humour directed at teachers, its types and social functions. The collected data are divided into three categories that describe different modes of teachers as targets of pupils’ humour. The first mode describes teachers as unintentionally comical, the second as duped by their pupils and the third as intentional users of humour. The analysis focuses on different functions that pupils’ humour directed at teachers fulfils in the social life of the classroom. The paper concludes by showing how key functions of social humour (such as creation of solidarity, negotiation of power and realisation of personal needs) are connected to the three modes of pupils’ humour directed at teachers.     

Gymnastics

Abstract

The aim of our research was to study the relationships between performance variables in a support backward swing (SBS), which was used as a progressive step in the learning procedure for a 1#fr1/4> straddle‐piked front somersault and the swing prior to a 1#fr1/4> straddle‐piked front somersault from support to bent arm support on the parallel bars (5/4S). Mitja Petkov?ek, parallel bars gold medallist at the 2000 EC in Bremen, performed these elements. Kinematic analysis involved CMAS software (Praha, 1993), and the Suskana body segment model that has 17 points and 15 segments. Kinetic variables were estimated using 2D IMGIM software, which has 8 points and 6 segments (Colja and ?uk, 1994). The results indicated that some kinematic aspects of the two types of swings were similar but there were important differences in kinetic aspects of the motion. During the swing for the 5/4S, force and torque were higher than in the SBS.     

The use of ICT devices by older people with a special focus on their type and respondents’ age: A Czech case study

The recent demographic trends show a rapid increase of aging population, especially in developed countries. Therefore, there is an urgent need to look for the opportunities of maintaining the quality of life of this aging population. One of the solutions seems to be the use of information and communication technology (ICT) devices, which can promote autonomy of older people by facilitating the execution of many routine activities such as shopping or communication. The purpose of this study is to explore the use of ICT devices among older people in the Czech Republic with respect to their type and respondents’ age. The methods include a questionnaire survey, as well as statistical processing of data collection. The results indicate that present seniors are becoming more digitally literate, especially in the use of mobile phones. However, the use of the technological devices then dramatically drops at the age of 75 years. In addition, the results indicate that future research should focus on the use of mobile phones, respectively smartphones, and its effectiveness on the improvement of quality of life of older generation groups.