Experimental validation of a continuous-time MCSI algorithm with bounded adaptive gains

Model reference adaptive control algorithms with minimal controller synthesis have proven to be an effective solution to tame the behaviour of linear systems subject to unknown or time-varying parameters, unmodelled dynamics and disturbances. However, a major drawback of the technique is that the adaptive control gains might exhibit an unbounded behaviour when facing bounded disturbances. Recently, a minimal controller synthesis algorithm with an integral part and either parameter projection or σ-modification strategies was proposed to guarantee boundedness of the adaptive gains. In this article, these controllers are experimentally validated for the first time by using an electro-mechanical system subject to significant rapidly varying disturbances and parametric uncertainty. Experimental results confirm the effectiveness of the modified minimal controller synthesis methods to keep the adaptive control gains bounded while providing, at the same time, tracking performances similar to that of the original algorithm.     

Returning after taking a break in online distance higher education: from intention to effective re-enrollment

One of online distance learning’s positive attributes is its flexibility. However, the possibility of engaging in periods of non-enrollment (breaks) usually ends in students dropping out. In this paper, the intention to continue of those students who have not enrolled in the second semester is analyzed, adopting a long-term program perspective. This continuance intention is compared with the subsequent restart (or dropping out) in the third semester. This analysis has confirmed that the models of continuance intention and effective re-enrollment are essentially different. Continuance intention is more rational, even logical, and is mainly based on the level of satisfaction or dissatisfaction with the educational experience (difficulty of the learning materials or perception of the learning system). Effective re-enrollment is more practical or pragmatic, with more importance given to the effects of student dimension variables, for example, motivations for studying, previous university experience, or environmental variables, such as having a job.     

On the role of impact evaluation of quality assurance from the strategic perspective of quality assurance agencies in the European higher education area

In this paper the current national legislations, the quality assurance approaches and the activities of impact analysis of three quality assurance agencies from Romania, Spain and Germany are described from a strategic perspective. The analysis shows that the general methodologies (comprising, for example, self-evaluation reports, peer reviews, on-site visits, assessment reports, follow-up measures) and main subjects of quality assurance in higher education (such as study programmes and institutional structures and processes) are very similar in the sample cases. However, up to now, impact evaluation of quality assurance has not been implemented systematically in the sample agencies (as in many others). This is the more relevant since the European standards of quality assurance in higher education oblige quality assurance agencies to analyse their general findings and observe the effects of their activities. Against that background, it is argued that methodologically sound impact analyses of quality assurance interventions in higher education institutions should be seen as an integral part of the agencies’ own quality assurance because it would make their work more transparent and easier to improve systematically. The paper identifies some professionalisation needs required for impact evaluation competences: staff and peers who are qualified by methodological knowledge but also by ‘soft’ skills such as project and conflict management.     

Was the Umayyad Caliphate of Cordoba as Strong as Arab Chroniclers Claimed?1

Arabic sources recall the tenth and early eleventh centuries as the time when Andalusian armies achieved their greatest military triumphs over the Christian kingdoms and counties of northern Iberia. Some of those victories were truly spectacular and their like would never happen again. However, this view is also the result of the concealment, justification, and minimisation of defeats, as well as of the exaggeration of the successes achieved. This follows from a critical reading of Muslim chronicles and from the study of the data provided by Latin sources. The present article discusses some of the aforementioned practices of chroniclers and analyses whether the image offered by Arab compilers overstated the true military potential of the Umayyad Andalusian Caliphate. It concludes that caliphal armies were already showing some alarming signs of weakness during this period.     

The virtual laboratory concept applied to strain measurements

In recent years the methodology of engineering education has been changing and many projects deal with improving the educational software. This paper reports on the virtual laboratory, a virtual environment applied to experimental analysis. The goals of the virtual laboratory are to introduce the laboratory environment to the student entering this world, so different from the typical theoretical lectures, for the first time, and to overcome the above-mentioned drawbacks. It should be mentioned that the virtual laboratory is not meant to replace highly enriching, practical experience, but rather is meant to train the individual, in order to improve his/her performance in later actual practice. The virtual laboratory experience starts with the study of strain measurements, an engineering technique widely used to measure deformations, strains, mechanical properties of materials and other variables which are used to analyse many problems.The strain measurement virtual laboratory is meant to offer the possibility of simulating experiences, undergone in a real laboratory, through the Internet. The student is expected to familiarize him/herself with the techniques, procedures, devices and theories in the laboratory environment.     

University students’ success: A psycho-sociological approach

The aim of this paper is to propose a basic model to analyse processes of change in educational institutions taking into account both individual and contextual variables. It aims to identify the basic factors of change in order to contribute to reduce the dispersion of research projects, both from close subjects and one subject alone within human sciences, in order to make scientific accumulation easier and to guide social practice better. This proposal is based on Cryer and Elton’s (Studies in Higher Education, 1: 75–86, 1990) contributions, in this case applied to the learning processes of university students. They may account for static and dynamic aspects. To prove its coherence, it has been statistically compared with the data of a survey carried out among university students in Catalonia (Spain).     

An interdisciplinary and application-oriented approach to teach microfluidics

Microfluidics is a relatively novel interdisciplinary research area with broad applications in chemistry, physics, material science, and biology. Despite the rapid growth of the field, students'' exposure to microfluidic technologies is still limited and often insufficient to appreciate the advantages over other commonly used technologies. To this end, we designed a five-day course, “Microfluidics for microbial ecology,” in which students with very different backgrounds learn the basics of microfluidic technologies and sample a range of applications in microbial ecology. The course was created for Master and Ph.D. students interested in applying microfluidics to their research and, therefore, followed an application-oriented approach. The presentation of critical aspects of fluid flow phenomena at the microscale and an outline of the advantages and constraints of the technology provide students with the background to design and perform microfluidics-based experiments. In order to improve the effectiveness of learning in a class with diverse interests and backgrounds, two active learning exercises were implemented. The first comprised the design of an individualized microfluidics experiment in parallel with the lectures: students were guided to apply each module to their personalized application and discuss it in groups. The second was a group experimental activity, in which students jointly set up, performed, analyzed, and presented a microfluidics-based experiment. Given the multidisciplinary teaching context, the course was able to foster common conceptual ground and promote discussion among students. This application-oriented approach built upon experimental activities and in-class discussion is well suited to promote learning in a technology-related subject such as microfluidics.     

Data-driven estimates of global nitrous oxide emissions from croplands

Croplands are the single largest anthropogenic source of nitrous oxide (N₂O) globally, yet their estimates remain difficult to verify when using Tier 1 and 3 methods of the Intergovernmental Panel on Climate Change (IPCC). Here, we re-evaluate global cropland-N₂O emissions in 1961–2014, using N-rate-dependent emission factors (EFs) upscaled from 1206 field observations in 180 global distributed sites and high-resolution N inputs disaggregated from sub-national surveys covering 15593 administrative units. Our results confirm IPCC Tier 1 default EFs for upland crops in 1990–2014, but give a ∼15% lower EF in 1961–1989 and a ∼67% larger EF for paddy rice over the full period. Associated emissions (0.82 ± 0.34 Tg N yr^–1) are probably one-quarter lower than IPCC Tier 1 global inventories but close to Tier 3 estimates. The use of survey-based gridded N-input data contributes 58% of this emission reduction, the rest being explained by the use of observation-based non-linear EFs. We conclude that upscaling N₂O emissions from site-level observations to global croplands provides a new benchmark for constraining IPCC Tier 1 and 3 methods. The detailed spatial distribution of emission data is expected to inform advancement towards more realistic and effective mitigation pathways.     

Do chimpanzees reason logically?

Psychologists disagree about the development of logical concepts such as or and not. While some theorists argue that infants reason logically, others maintain that logical inference is contingent on linguistic abilities and emerges around age 4. In this Registered Report, we conducted five experiments on logical reasoning in chimpanzees. Subjects (N = 16; 10 females; M = 24 years) participated in the same setup that has been administered to children: the two-, three-, and four-cup-task. Chimpanzees performed above chance in the two-cup-, but not in the three-cup-task. Furthermore, chimpanzees selected the logically correct option more often in the test than the control condition of the four-cup-task. We discuss possible interpretations of these findings and conclude that our results are most consistent with non-deductive accounts.