Real time implementation of indirect rotor flux oriented control of a five-phase induction motor with novel rotor resistance adaption using sliding mode observer

High performance multiphase motor drive requires precise knowledge of the state quantities and the machine parameters. Access to these state quantities is through measurement using sensors whose accuracy is paramount to achieve the performance level required by industrial applications. However, the problems of the parameters variations, inaccessibility to the measurement of some states, no-observability of the machine in some regions, the cost of the sensors and their lack of precision, make this very difficult task. To address these problems, it is necessary to resort to soft sensors through the design of observers and estimators. In multiphase induction motor drive, the observation problem arises especially for rotor flux that is not accessible for measurement. About the parameters variations, the rotor resistance and the stator resistance are the most critical parameters of the machine because their influence is crucial for the control and observation. The change in the resistances can be as large as 40–50% of the rated value, which may affect the control adversely. This paper develops a new structure of an adaptive sliding mode observer based on an online estimation of the rotor resistance value in order to avoid the effect of its variation in the rotor flux oriented control. The results show convergent (the errors in the transient and steady states are 5% and 1%, respectively) behavior of the drive using the proposed control scheme for large rotor resistance variation under loaded condition. The stability of the drive is proved using Lyapunov criteria. The simulation results are validated using real time implementation.     

The impact of Nordic walking training on the gait of the elderly

The purpose of the current study was to define the impact of regular practice of Nordic walking on the gait of the elderly. Thereby, we aimed to determine whether the gait characteristics of active elderly persons practicing Nordic walking are more similar to healthy adults than that of the sedentary elderly. Comparison was made based on parameters computed from three inertial sensors during walking at a freely chosen velocity. Results showed differences in gait pattern in terms of the amplitude computed from acceleration and angular velocity at the lumbar region (root mean square), the distribution (Skewness) quantified from the vertical and Euclidean norm of the lumbar acceleration, the complexity (Sample Entropy) of the mediolateral component of lumbar angular velocity and the Euclidean norm of the shank acceleration and angular velocity, the regularity of the lower limbs, the spatiotemporal parameters and the variability (standard deviation) of stance and stride durations. These findings reveal that the pattern of active elderly differs significantly from sedentary elderly of the same age while similarity was observed between the active elderly and healthy adults. These results advance that regular physical activity such as Nordic walking may counteract the deterioration of gait quality that occurs with aging.     

Examining the influence of intermediaries in facilitating e-government adoption: An empirical investigation

The adoption and diffusion of electronic government is often impeded by many social and individual factors relating to citizens. In this respect, intermediaries have emerged as a new model for delivering e-government services to overcome such obstacles. This study aims to examine the role of intermediaries in facilitating e-government adoption and diffusion using a survey based empirical study of 502 participants in Madinah City in Saudi Arabia. An extended UTAUT model is used as the theoretical basis utilizing trust in the Internet and Intermediaries. The results of this study show that there are significant relationships among the factors that influence intention to use e-government, namely, performance expectancy, effort expectancy, and trust of intermediary. In addition, the findings show that there is a significant relationship between facilitating conditions and usage behavior proving that intermediaries can influence adoption of e-government services.     

Predicting student ratings: the relationship between actual student ratings and instructors’ predictions

This study examined the relationship between student ratings and instructors’ predictions of these ratings, taking into account other instructor, student, and course characteristics. Participants in the study were 198 instructors in the School of Education at a major teacher training college in Israel. Data corresponding to one randomly selected course per instructor were collected using student and instructor questionnaires and college records. Results indicate a systematic positive relationship between instructors’ predictions and actual student ratings with respect to overall ratings and the ratings of three dimensions of teaching. Results also demonstrate a systematic trend whereby low‐rated instructors tend to overestimate their student ratings, high‐rated instructors underestimated ratings, and moderately rated instructors gave accurate predictions. Results have implications for using predictions to motivate teaching improvement.     

Contextual and pedagogical considerations in teaching for forgiveness in the Arab world

This study was conducted among Arab teachers in four countries in the Middle East (Jordan, Lebanon, Egypt and Palestine) to examine their views and methods on teaching for forgiveness in their classrooms. A total of 87 teachers in K-12 classrooms participated in semi-structured interviews as part of a larger study on teaching for forgiveness in the region. Thematic analyses of interviews suggested that teachers created opportunities to model and teach forgiveness as part of their civics education curriculum. They also expressed eagerness for instructional guidance and curriculum materials to systematically teach forgiveness in schools. The strength of religion and historical religious figures as positive sources for teaching forgiveness was also evident. Findings highlight the need to integrate education for peace and forgiveness in the education system, especially as a result of recent political developments in the Middle East, and to provide methods to assist teachers to do so in their classrooms.     

Science Teachers’ Views and Stereotypes of Religion,Scientists and Scientific Research: A call for scientist–science teacher partnerships to promote inquiry-based learning

Despite a growing consensus regarding the value of inquiry-based learning (IBL) for students’ learning and engagement in the science classroom, the implementation of such practices continues to be a challenge. If science teachers are to use IBL to develop students’ inquiry practices and encourage them to think and act as scientists, a better understanding of factors that influence their attitudes towards scientific research and scientists’ practices is very much needed. Within this context there is a need to re-examine the science teachers’ views of scientists and the cultural factors that might have an impact on teachers’ views and pedagogical practices. A diverse group of Egyptian science teachers took part in a quantitative–qualitative study using a questionnaire and in-depth interviews to explore their views of scientists and scientific research, and to understand how they negotiated their views of scientists and scientific research in the classroom, and how these views informed their practices of using inquiry in the classroom. The findings highlighted how the teachers’ cultural beliefs and views of scientists and scientific research had constructed idiosyncratic pedagogical views and practices. The study suggested implications for further research and argued for teacher professional development based on partnerships with scientists.     

DistanceRank: An intelligent ranking algorithm for web pages

A fast and efficient page ranking mechanism for web crawling and retrieval remains as a challenging issue. Recently, several link based ranking algorithms like PageRank, HITS and OPIC have been proposed. In this paper, we propose a novel recursive method based on reinforcement learning which considers distance between pages as punishment, called “DistanceRank” to compute ranks of web pages. The distance is defined as the number of “average clicks” between two pages. The objective is to minimize punishment or distance so that a page with less distance to have a higher rank. Experimental results indicate that DistanceRank outperforms other ranking algorithms in page ranking and crawling scheduling. Furthermore, the complexity of DistanceRank is low. We have used University of California at Berkeley’s web for our experiments.     

Performance contagion and human resource layout: New concepts in performance management

Job performance can be defined as the extent to which one exhibits behaviors that further the goals of the organization, and leaders try to manage the factors influencing the performance in an organization to guide it toward organizational goals. A main factor that influences the performance is emotions and behavior of other people. The influence of people on each other can be divided into physical and metaphysical contagions in the scientific literature. In this article, we introduce a new kind of metaphysical contagion that has a close relationship with individual and organizational performance. We name it performance contagion and introduce two kinds of factors (content and process) and subfactors. We conceptualize a new concept in performance management defined as human resource layout. Tools are suggested for applying the steps of this model to improve both individual and organizational performance.     

Sequence-dependent rotation axis changes in tennis

The purpose of this study was to evaluate the role of rotation axes during a tennis serve. A motion capture system was used to evaluate the contribution of the potential axes of rotation (minimum inertia axis, shoulder-centre of mass axis and the shoulder-elbow axis) during the four discrete tennis serve phases (loading, cocking, acceleration and follow through). Ten ranked athletes (International Tennis Number 1–3) repeatedly performed a flat service aiming at a target on the other side of the net. The four serve phases are distinct and thus, each movement phase seems to be organised around specific rotation axes. The results showed that the limbs’ rotational axis does not necessarily coincide with the minimum inertia axis across the cocking phase of the tennis serve. Even though individual serving strategies were exposed, all participants showed an effect due to the cocking phase and changed the rotation axis during the task. Taken together, the results showed that despite inter-individual differences, nine out of 10 participants changed the rotation axis towards the minimum inertia and/or the mass axis in an endeavour to maximise external rotation of the shoulder to optimally prepare for the acceleration phase.