Widely linear estimation for multisensor quaternion systems with mixed uncertainties in the observations

The optimal widely linear state estimation problem for quaternion systems with multiple sensors and mixed uncertainties in the observations is solved in a unified framework. For that, we devise a unified model to describe the mixed uncertainties of sensor delays, packet dropouts and uncertain observations by using three Bernoulli distributed quaternion random processes. The proposed model is valid for linear discrete-time quaternion stochastic systems measured by multiple sensors and it allows us to provide filtering, prediction and smoothing algorithms for estimating the quaternion state through a widely linear processing. Simulation results are employed to show the superior performance of such algorithms in comparison to standard widely linear methods when mixed uncertainties are present in the observations.     

Accessibility and Product Ecosystems

Products, including assistive and accessible technologies, do not exist in isolation. They are all part of rich product ecosystems; they inhabit specific niches of economics, functionality, and technology, and they interact with other products. The concept of product ecosystem goes beyond technological interoperability. For accessibility to advance, we must understand more about the interactions among products. This article sketches an explanatory approach that may be useful in understanding how accessible technologies thrive, survive, or fail within their ecosystems.     

Pre-exercise antioxidant enzyme activities determine the antioxidant enzyme erythrocyte response to exercise

Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H₂O₂ (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.     

A Descriptive Analysis of Elite-Level Racquetball

In this study, we used social cognitive career theory (Lent, Brown, &; Hackett, 1994) to examine the development of female athletes' career interest in coaching and, specifically, the impact of contextual factors (female coaching role models, working hours, and perceived discrimination) on coaching self-efficacy and outcome expectations. Participants were 205 predominantly White, heterosexual female student athletes. A path analysis indicated that role models and working hours predicted coaching self-efficacy, which predicted coaching outcome expectations. Additionally, coaching self-efficacy, coaching outcome expectations, and contextual factors predicted coaching interest. Practical implications are discussed as well as suggestions for further research in this relatively unexplored area.     

Personalizing and Contextualizing Multimedia Case Methods in University-based Teacher Education: An Important Modification for Promoting Technological Design in School Science

Results of various studies suggest that multimedia ‘case methods’ (activities associated with case documentaries) have many benefits in university-based teacher education contexts. They can, for example, help to ‘bridge the gap’ between perspectives and practices held by academic teacher educators and those held by student-teachers – who may adhere to perspectives and practices commonly supported in schools. On the other hand, some studies, along with theoretical arguments, suggest that there are limits to the effectiveness of multimedia case methods – because, for example, they can never fully represent realities of teaching and learning in schools. Furthermore, often missing from multimedia case methods is the student-teacher in the role of teacher. To address these concerns, we modified an existing multimedia case method by associating it with a special practice teaching situation in a school context. Qualitative data analyzed using constant comparative methods suggest that student-teachers engaged in this modified multimedia case method developed relatively deep commitments to encouraging students to conduct technology design projects – a non-traditional practice in school science. Factors that appeared to influence development of this motivation included student-teachers’ pre-instructional perspectives about science and the personalization and contextualization inherent to the modified multimedia case method.

Higher expertise,pedagogic rights and the post-truth society

ABSTRACT

This paper discusses the nature of higher expertise in society and the role of higher education in constituting that expertise. It is argued that higher expertise relies on disciplined norms against which expert activity can be evaluated, and such norms are the basis not only for knowledge communities in higher education but also for other societal institutions. However, expertise in these communities and institutions is challenged by ‘post-truth’ developments that are fuelled by the marketisation and commodification of expertise, and by a collapse in deference and trust throughout society to which expert institutions and communities have not yet adequately responded. The consequences for higher education can be usefully explored via Durkheim’s discussion of the social organisation of religion and magic. Bernstein’s pedagogic rights of enhancement, inclusion and participation are subsequently examined to offer insight into how higher expertise may be sustained in such a context.     

University physics students' use of models in explanations of phenomena involving interaction between metals and electromagnetic radiation

We examine third year university physics students' use of models when explaining familiar phenomena involving interaction between metals and electromagnetic radiation. A range of scientific models are available to explain these phenomena. However, explanations of these phenomena tend not to be used as exemplars of scientific models within undergraduate physics education. The student sample is drawn from six universities in UK and Sweden. These students have difficulties in providing appropriate explanations for the phenomena. Many students draw upon the Bohr model of isolated atoms when explaining light emission of metals. The students tend not to recognize that atoms in metals interact to give an electronic structure very different from that of the isolated atom. Few students use a single model consistently in their explanations of these related phenomena. Rather, students' use of models is sensitive to the context in which each phenomenon is presented to them.     

Enhancement of Online and Offline Student Learning

An attempt is made in this paper to outline the commonly reported features of constructivism and collaborative learning as they might underpin a proposed model of ICT support for learning. This model is then evaluated for its use in examining three projects involving ICT in student learning environments. The focus of the proposed model is on the pedagogic issues relating to the design of ICT learning environments, effectiveness of student learning and the wider promotion of ICT inlearning.

Encouragement de l'apprentissage de l'enseigné en ligne et hors ligne

Dans cet article on cherche à mettre en valeur les aspects du constructivisme et l'acquisition des apprentissages collectifs qui peuvent s'entendre en modèle proposé de support ICT d'apprentissage. On évalue ensuite ce modèle utilisé en examinant 3 projets impliquant les ICT dans l'environnement de l'apprentissage des étudiants. L'accent du modèle proposé est mis sur les aspects pédagogiques relatifs à la conception des enrichissements des ICT, à l'efficacité de l'apprentissage de l'enseigné et la promotion a plus large de ICT dans l'apprentissage.

Die Verbesserung von Online und Offline Lernleistung

In diesem Papier wird versucht, die allgemein berichteten Eigenschaften von Konstruktivismus und gemeinschaftlichem Lernen in Bezug auf ein vorgeschlagenes IKT-Lernunterstützungsmodell zu umreißen. Der Einsatz dieses Modells wird sodann bei drei Projekten, in denen IKT in die Lernumgebung der Studenten einbezogen ist, evaluiert. Der Schwerpunkt des vorgeschlagenen Modells liegt auf den pädagogischen Aspekten von IKT-Lernumgebungen in Bezug auf ihre Gestaltung, der Lerneffektivität und der weiteren Förderung der Nutzung von IKT für das Lernen.     

Educational Broadcasting and the New Technologies

Those of us who work in education and in broadcasting have been dominated, for many years now, with thought, discussion and innumerable papers — almost to the point of tedium — with what we call ‘new technology’. What we mean by new technology are those aspects of the enormous space race-induced changes in the last quarter of the twentieth century which directly affect the making and using of audio-visual materials.