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Grimstad, Norway

University of Agder is a public university with campuses in Kristiansand and Grimstad, Norway. The institution was established as a university college in 1994 with the merger of six colleges and was granted its current status as a university in 2007, but its academic activity dates as far back as 1839. It is one of eight universities in Norway; the other seven are the University of Oslo, the University of Tromsø, the University of Stavanger, the University of Bergen, the Norwegian University of Life science in Ås, the Norwegian University of Science and Technology in Trondheim and the University of Nordland in Bodø. Wikipedia.

In this paper, a sliding-mode approach is proposed for exponential H ∞ synchronization problem of a class of masterslave time-delay systems with both discrete and distributed time-delays, norm-bounded nonlinear uncertainties and Markovian switching parameters. Using an appropriate LyapunovKrasovskii functional, some delay-dependent sufficient conditions and a synchronization law, which include the masterslave parameters are established for designing a delay-dependent mode-dependent sliding mode exponential H ∞ synchronization control law in terms of linear matrix inequalities. The controller guarantees the H ∞ synchronization of the two coupled master and slave systems regardless of their initial states. Two numerical examples are given to show the effectiveness of the method. © 2011 The Franklin Institute. Published by Elsevier Ltd. All rights reserved. Source

Li H.,Bohai University | Jing X.,Hong Kong Polytechnic University | Karimi H.R.,University of Agder
IEEE Transactions on Industrial Electronics

This paper deals with the problem of output-feedback H∞ control for a class of active quarter-car suspension systems with control delay. The dynamic system of the suspension systems is first formed in terms of the control objectives, i.e., ride comfort, road holding, suspension deflection, and maximum actuator control force. Then, the objective is to the design of the dynamic output-feedback H∞ controller in order to ensure asymptotic stability of the closed-loop system with H∞ disturbance attenuation level and the output constraints. Furthermore, using Lyapnov theory and linear matrix inequality (LMI) approach, the existence of admissible controllers is formulated in terms of LMIs. With these satisfied conditions, a desired dynamic output-feedback controller can be readily constructed. Finally, a quarter-vehicle model is exploited to demonstrate the effectiveness of the proposed method. © 1982-2012 IEEE. Source

Seiler S.,University of Agder
International Journal of Sports Physiology and Performance

Successful endurance training involves the manipulation of training intensity, duration, and frequency, with the implicit goals of maximizingperformance, minimizing risk of negative training outcomes, and timing peak fitness and performances to be achieved when they matter most. Numerous descriptive studies of the training characteristics of nationally or internationally competitive endurance athletes training 10 to 13 times per week seem to converge on a typical intensity distribution in which about 80% of training sessions are performed at low intensity (2 mM blood lactate), with about 20% dominated by periods of high-intensity work, such as interval training at approx. 90% VO2 max. Endurance athletes appear to self-organize toward a high-volume training approach with careful application of high-intensity training incorporated throughout the training cycle. Training intensification studies performed on already well-trained athletes do not provide any convincing evidence that a greater emphasis on high-intensity interval training in this highly trained athlete population gives long-term performance gains. The predominance of low-intensity, long-duration training, in combination with fewer, highly intensive bouts may be complementary in terms of optimizing adaptive signaling and technical mastery at an acceptable level of stress. © Human Kinetics, Inc. Source

Wiki technology provides new opportunities to foster collaborative writing in teacher education. To empirically evaluate the level of collaborative writing in a wiki-based environment, this article used three methods and their combination. The first method was the history function that records all students' actions, enabling to trace all changes made in the wikis. The actions were analyzed in terms of number and percentage of contribution using a taxonomy categorized by 10 editorial types. The second method examined comments posted on the wiki discussion page to evaluate the level of collaboration. The third method provided feedback on the level of collaboration by means of peer assessment. The results show important differences in the types of contributions across the categories investigated. The results also reveal that the level of collaborative writing was lower than expected. Possible factors that may influence wiki-based collaborative writing are discussed. Finally, suggestions for effective use of wikis as collaborative writing tools in teacher education conclude the article. © 2013 Elsevier Ltd. All rights reserved. Source

There has been an increase in screen-based communication, leading to concerns about the negative health effects of screen-based activities in children and adolescents. The present study aimed to (1) analyze changes in screen time activity in Norwegian children from 2001 to 2008, and (2) to analyze associations between the changes in screen time activity over time and sex, grade level and parental educational level. Within the project Fruits and Vegetables Make the Marks (FVMM), 1488 6th and 7th grade pupils from 27 Norwegian elementary schools completed a questionnaire including a question about time spent on television viewing and personal computer use in 2001 and 1339 pupils from the same schools completed the same questionnaire in 2008. Data were analyzed by multilevel linear mixed models. The proportions of 6th and 7th grade pupils at the 27 schools that reported screen time activity outside school of 2 hours/day or more decreased from 55% to 45% (p<0.001) from 2001 to 2008 when adjusting for sex, grade level and parental education. The decrease was most evident in 6th graders (51% to 37%) and in children with highly educated parents (54% to 39%). The present study shows that there has been a marked reduction in screen time activity outside school in this group of Norwegian 10-12 year olds from 2001 to 2008. Source

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