Discrete time sliding mode controllers with relative degree one and two switching variables

In this paper, a new reaching law based sliding mode control strategy for discrete time systems is introduced. Contrary to most existing approaches, the new strategy uses a sliding variable with relative degree two. It is demonstrated that the new reaching law drives the sliding variable to a narrower quasi-sliding mode band than its relative degree one equivalent, while simultaneously ensuring the desired dynamic properties of the system. Furthermore, it is shown that the smaller quasi-sliding mode band width is reflected in reduced magnitude of all state variables in the sliding mode.     

Multilevel information system— Towards more flexible information retrieval systems

The Multilevel Information System (MLIS), extension of typical Information Retrieval System towards more complete data processing, is discussed. MLIS integrates functions typical for data base management systems and retrieval-oriented systems. Several levels of data accessing are provided, each level developed for a different class of users. End-user level is based on simple query language, trained user level on a relational model, and application programmer level on a Data Manipulation Language nested in high level programming language. The last two levels are discussed in detail.     

Rattle Running,Dry Wrestling,and Boxing in … Opera,or Regional Sports and Games in the Historical and Cultural Tradition of Eastern Europe

Abstract

The article is a heartfelt plea to both Western and Eastern European sports historians to take full account of the rich sporting history of the eastern part of the continent of Europe. After describing how most of Eastern Europe fell under the domination of foreign empires, and how this lead to a disparaging attitude towards its peoples and cultures, the author specifically details how Western authors of both general cultural histories and sporting histories and encyclopaedias have ignored Eastern Europe to a quite astonishing extent. The author then goes on to argue that Eastern Europe has a sporting tradition which is at least as rich, if not richer than that of the West. To illustrate this, the phenomena of medieval Polish horse racing, Bulgarian dry wrestling, Russian folk pugilism, Polish religious games, and Asian-influenced archery are explained in some detail. It is hoped that these examples will inspire sports historians from all parts of Europe to tap the rich resources of the East, and to treat this part of Europe as central rather than peripheral to European cultural history.     

A study of technical innovation in Polish industry

This paper presents the results of research covering 86 innovations from seven Polish industries. The sample of innovations includes traditional and modern branches - clothing, leather and automotive industry; intermediate products - synthetic fibres and dyestuffs; capital goods - textile machinery; and final consumption goods - furniture and electrical equipment. The purpose of the research was to identify the stimuli and restraints on innovation, especially from the economics and financial system of enterprises in which the innovations were implemented.The research findings show that process innovations are more frequent than product innovations and that Polish enterprises innovate more often because of a need to overcome supply shortages than to meet demand needs. There is evidence of the dominance of in-house developments based on wide utilisation of foreign technological knowledge, both from socialist and from capitalist countries. The important pressure to innovate comes in current economic conditions from research establishments and the above enterprise level (associations and industrial ministries). This study also showas the important role of the non-financial motivations of individuals to engage in innovations,and the existence of some weak points in financial incentives to promote innovations. The Last fact partly explains, The former findings.     

Parental perspectives of home-schooling of children with special educational needs and disabilities during the COVID-19 pandemic: a review

The purpose of this paper is to review recent literature on parental perspectives of the impact of the COVID-19 pandemic on the home-schooling of children with special educational needs and disabilities, as well as to consider implications for their education and well-being. Eleven papers were reviewed, published between 2020 and 2021, selected according to a systematic protocol from three widely used online databases. Analysis of the reviewed papers found that transitioning to home-schooling during the pandemic had negative consequences for most of the children, as well as for their parents, though a small but significant number reported positive consequences. Three key areas of concern were identified in the analysis: balancing home-schooling with parent work activities; parent relationships with schools and support services and agencies and home-schooling effects on the well-being and mental health of parents and children.     

Oculomotor dynamics in skilled soccer players: The effects of sport expertise and strenuous physical effort

The ability to quickly locate objects within the visual field has a significant influence on athletic performance. Saccades are conjugate eye movements responsible for the rapid shift that brings a new part of the visual field into foveal vision. The aim of this study was to investigate the effects of sport expertise and intense physical effort on saccade dynamics during a free-viewing visual search task in skilled soccer players. Two groups of male subjects participated in this study: 18 soccer players and 18 non-athletes as the control group. Two sessions of visual search tasks without a sport-specific design were employed. Eye movements during the visual search tasks were recorded binocularly. Between pre- and post-test sessions, athletes performed a maximal incremental treadmill test. Cardiorespiratory parameters were measured continuously. Capillary lactate samples were collected. Pre-test findings indicated that athletes, in comparison to non-athletes, achieve higher values of the following characteristics of saccades (1) average acceleration, (2) acceleration peak, (3) deceleration peak, and (4) average velocity. An increase in post-test saccade duration and a decrease in post-test saccade velocity was observed in athletes due to the strenuous physical effort in relation to the pre-test state. Athletes may transfer high saccadic function efficiency to non-specific visual stimuli. The findings partially confirm that physical exertion can reduce oculomotor efficiency in athletes.