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.     

Managing personal human capital for professional excellence: an attempt to design a practical methodology

Within the context of the knowledge-based economy, individuals increasingly control their own development, careers and destinies, rather than the organisations that employ them. Work drawing on the new career orientations has been mostly conceptual rather than empirical. The existing literature focuses mainly on explaining the conditions under which new career orientations emerge and the changes these can bring to the lives of individuals. However, we found that there is no practical methodology to help individuals face the challenges of the future in a proactive manner. The aim of this paper is to develop a practical methodology (the PHCN – Personal Human Capital Navigator) that helps individuals to systematically manage their personal human capital so they can achieve their strategic objectives and outstanding results.     

Modellierung und Simulation hybrider Systeme mit Smile

Zusammenfassung. Es wird eine werkzeugunterstützte Entwicklungsmethodik vorgestellt, die der Erstellung von Berechnungsmodellen für die Simulation hybrider physikalisch-technischer Systeme dient. Dafür werden verschiedene Modellbeschreibungstechniken dargestellt und klassifiziert, die anschlie?end in einen falltypischen Entwicklungsproze? eingebettet werden, der auf hybriden Erweiterungen von UML und Z basiert. Die Simulationsumgebung Smile (http://buran.fb10.tu-berlin.de/Energietechnik/EVT\_KT/smile/) erm?glicht schlie?lich die generische Erzeugung eines ausführbaren Simulators. Architektur und Kernkomponenten dieses Systems, wie beispielsweise L?sungsverfahren und Experimentshell, werden eingehender diskutiert. Ein Anwendungsbeispiel illustriert den beschriebenen Entwicklungsproze?. Eingegangen am 15. Juli 1999 / Angenommen am 12. November 1999     

Physical activity and school recess time: differences between the sexes and the relationship between children's playground physical activity and habitual physical activity

The aims of this study were: (1) to observe participation in moderate-to-vigorous physical activity (MVPA) during school recess periods; (2) to determine the relative importance of physical activity during recesses to overall daily physical activity; and (3) to examine differences in physical activity between the sexes during unstructured recess periods. The participants were 22 school children (10 boys, 12 girls) aged 8 - 10 years (mean = 8.9, s = 0.7) in the third and fourth grades. Daily totals for the physical activity variables were calculated by summing the values for each hour of 14 h of physical activity measurements (08:00 to 22:00 h). Recess times (minutes) were as follows: morning 10:30 to 11:00 h and afternoon 15:30 to 16:00 h. We did not differences between boys and girls in daily total accelerometer counts or the overall time spent in MVPA. However, girls were significantly (P < 0.05) more involved (38%) in MVPA during recess time than boys (31%). Participation in MVPA during recess contributes significantly more (P < 0.05) for girls (19%) than boys (15%) to the total amount of physical activity suggested by international health-related physical activity guidelines, while the percentage of time engaged in MVPA during recess time at school accounts for a small amount of the daily MVPA (6% for boys and 8% for girls). The results of this study suggest that school recess time is an important setting to promote MVPA and contributes to daily physical activity in young children, especially in girls.     

On refusing the Balkanization of the African university

‘Neither the African governments nor anyone else can be satisfied with the present performance of the universities on the continent. If quantitatively speaking the results are not bad, as soon as one tackles the question of all the content of education, the quality of education and, above all, the problem of the distribution of students among various faculties, the picture looks completely different.’