A nonlinear PID controller based novel maximum power point tracker for PV systems

This paper proposes a novel application of Nonlinear Proportional-Integral-Derivative (NPID) controller to effectively attain Maximum Power Point Tracking (MPPT) in Photovoltaic (PV) systems. The proposed controller is based on the basic structure of the PID controller wherein, its integral term gain is varied at run time according to instantaneous error. The performance of the NPID controller is assessed in terms of undershoot, settling time and ripple which have been evaluated under varying realistic irradiation and temperature profiles. The Teaching Learning Based Optimization (TLBO) tuned NPID controller is found to be superior to TLBO tuned PID, Perturb and Observe and Incremental Conductance classical MPPT methods for all the considered environmental profiles. Therefore, based on the presented comprehensive investigations, it is concluded that the proposed NPID controller is a promising MPPT technique.     

The benefits of overseas study for international postgraduate students in Malaysia

This paper investigates the benefits of overseas tertiary education for international postgraduate students enrolled at a research-intensive university in Malaysia, an emerging yet under-researched Asian education hub. The study is based on 55 semi-structured qualitative interviews with international students and academic and professional support staff. Our analysis identified three sets of benefits linked to specific economic, educational, social and cultural pull factors: academic success, building knowledge and skills, and contributing to home country on return. Our analysis illustrates the interplay between macro and meso-level actors and policies in shaping the micro-level experiences of international students. The paper contributes new insights into vital nuances in the nature and lived experience of the key benefits of international education relating to academic success and time, language learning and friendship, and employability and ‘giving back’.     

Incidence of microalbuminuria in hypertensive patients

The prevalence of microalbuminuria was assessed in 174 albustix negative hypertensive patients by estimating albumin in the morning random urine samples by immunoturbidimetric method within four hours of voiding of urine. The urine samples were not stored and collected without any preservatives. The urinary albumin was calculated in terms of ratio with respect to urinary creatinine and expressed as albumin creatinine ratio (mg/g). Out of 174 albustix negative hypertensives, 58 (33.3%) patients were found to have microalbuminuria. The prevalence of microalbuminuria in males and females was found to be 34% and 30.7% respectively. No correlation was found between the Body Mass Index (BMI) and albumin excretion (r² = 0.0271) and between duration of hypertension and urinary albumin excretion (r² = 0.0042). Prevalence of microalbuminuria in nonsmokers and non-alcoholic hypertensives was 20%. The prevalence in alcoholics, smokers and both smokers and alcoholics was found to be 35%, 42% and 41% respectively. The high prevalence of microalbuminuria than the various reported studies on the subject demands establishment of a screening programme for microalbuminuria, implementation of specific intervention methods and education of hypertensive patients about the consequences of smoking and alcohol on possible involvement of renal system.     

Democracy at work in and through experimental schooling

Through an exploration of two experimental schools, Oruaiti (1950s) and Discovery 1 (2000s), we aim to understand the socio-political contexts that create spaces for experimentation and examine their impact on mainstream schooling. Caught between competing, often contradictory, discourses such experiments struggle between the ‘regeneration’ and ‘reproduction’ functions of schooling. However, we argue that while they have limited impact on mainstream school reform, they contribute ideas of a democratic society and its citizenry. Consequently, they provide ‘windows’ into real-life laboratories in which social debates regarding the function and power of schooling, and specific visions of democracy are played out.     

Use of Internet services and resources in the engineering colleges of Punjab and Haryana (India): A study

This article reports a survey on the use of Internet services and resources in the engineering colleges of Punjab and Haryana states of India. Data were collected by using a questionnaire and follow-up interviews with Internet users, i.e. teachers and students of engineering colleges. The response rate was 80.8%. Results showed that all the respondents make frequent use of the Internet because they have access either at college or at home. The survey revealed that the majority of the respondents, i.e. 65.6%, access the Internet from college or their workplace. More than 75% of the respondents use the Internet services mainly for educational and research purposes. Google and Yahoo search engines are found to be more widely used than other search engines. More than 70% of the respondents feel that the Internet is useful, informative, easy to use, inexpensive and time saving.     

Determining the Intelligibility of Einsteinian Concepts with Middle School Students

Research in Science Education - The modern Einsteinian conception of space, time, matter and radiation represents a radical paradigm shift compared with the traditional Newtonian physics that...     

Children and the Internet: experiments with minimally invasive education in India

Urban children all over the world seem to acquire computing skills without adult intervention. Indeed this form of self-instruction has produced hackersÑchildren who can penetrate high tech security systems. Is this kind of learning dependent only on the availability of technology? We provided slum children in New Delhi with Internet access in their settlement. The paper describes the results obtained in the first month of unsupervised and unguided access. It is observed that children seem to understand and use the technology fluently. Language and formal education do not seem to make any significant difference.     

Are contextual and designed student–student interaction treatments equally effective in distance education?

This systematic review draws from and builds upon the results of a meta-analysis of the achievement effects of three types of interaction treatments in distance education: student–student, student–teacher, and student–content (Bernard et al., Review of Educational Research, 79(3), 1243–1289, 2009). This follow-up study considers two forms of student–student interaction treatments, contextual interaction and designed interaction. Typical contextual interaction treatments contain the necessary conditions for student–student interaction to occur, but are not intentionally designed to create collaborative learning environments. By contrast, designed interaction treatments are intentionally implemented collaborative instructional conditions for increasing student learning. Our meta-analysis compared the effect of these two types of interaction treatments on student achievement outcomes. The results favored designed interaction treatments over contextual interaction treatments. Examples of designed interaction treatments and a discussion of study results and their potential implications for research and instruction in distance education and online learning are presented.